Sirindhorn International Institute of Technology

About: Sirindhorn International Institute of Technology is a based out in . It is known for research contribution in the topics: Supply chain & Combustion. The organization has 1048 authors who have published 1678 publications receiving 30067 citations.

Understanding roles of E × B flow and magnetic shear on the formation of internal and edge transport barriers using two-field bifurcation concept

Abstract: A set of heat and particle transport equations with the inclusion of E × B flow and magnetic shear is used to understand the formation and behaviors of edge transport barriers (ETBs) and internal transport barriers (ITBs) in tokamak plasmas based on two-field bifurcation concept. A simple model that can describe the E × B flow shear and magnetic shear effect in tokamak plasma is used for anomalous transport suppression with the effect of bootstrap current included. Consequently, conditions and formations of ETB and ITB can be visualized and studied. It can be seen that the ETB formation depends sensitively on the E × B flow shear suppression with small dependence on the magnetic shear suppression. However, the ITB formation depends sensitively on the magnetic shear suppression with a small dependence on the E × B flow shear suppression. Once the H-mode is achieved, the s-curve bifurcation diagram is modified due to an increase of bootstrap current at the plasma edge, resulting in reductions of both L-H and H-L transition thresholds with stronger hysteresis effects. It is also found that both ITB and ETB widths appear to be governed by heat or particle sources and the location of the current peaking. In addition, at a marginal flux just below the L-H threshold, a small perturbation in terms of heat or density fluctuation can result in a transition, which can remain after the perturbation is removed due to the hysteresis effect.

Polylactic acid glycolysate as a cross-linker for epoxidized natural rubber: Effect of cross-linker molecular weight

Abstract: Hydroxyl-capped polylactic acid (PLA) oligomers are prepared by glycolysis reaction of PLA with ethylene glycol (EG) and used as a macromolecular cross-linker for epoxidized natural rubber (ENR). T...

Finite element analysis of bone around a dental implant supporting a crown with a premature contact.

Abstract: Objective: To investigate the influence of a premature contact caused by an implant-retained crown (IRC) on stress and strain distributions in bone surrounding the implant using the finite element method. Material and Method: A 3D finite element (FE) model of a section of a mandible with a single tooth dental implant, an IRC, and two adjacent teeth was created. Three rigid plates were used to represent the antagonist teeth. Modeling the antagonist teeth using the rigid plates removed the necessity to create FE models for the antagonist teeth, their periodontal ligament, and the maxilla. Moreover, this new approach also allowed the premature contact height to be easily varied by changing the positions of the rigid plates. In the present study, premature contact heights of 0, 50, 100, 150, 200 and 250 μm were considered. The FE contact analysis was employed. All materials were assumed to be linear elastic and isotropic. Results: The magnitudes of von Mises stresses in the bone change drastically when there was a premature contact. For example, the von Mises stress increased from 9.68 MPa in the case with no premature contact to 49.92 MPa in the case with the premature contact height of 50 μm. In addition, the magnitude of the major principal strain in the marginal bone reached the pathologic overload of 4000 μe when the premature contact height was 100 μm or higher. Conclusion: The influence of premature contacts is very high and the premature contact height of an IRC over 100 μm should be avoided as much as possible to provide longevity of dental implants.

Encapsulation of plumbagin using cyclodextrins to enhance plumbagin stability: computational simulation, preparation, characterization, and application

Abstract: Encapsulation of plumbagin using cyclodextrins (CDs), including α-cyclodextrin (αCD), β-cyclodextrin (βCD), and γ-cyclodextrin (γCD) to form inclusion complexes was investigated to prevent the loss of plumbagin in pharmaceutical and nutraceutical products. Computational simulations and phase solubility studies suggest that the complex formations of plumbagin with CDs are possible. βCD is chosen, as it has the lowest price and can form the complex in a wide concentration range with 1:1 host–guest molar ratio. Two techniques of the complex formation, co-precipitation and freeze-drying, were evaluated for both pure plumbagin and extracted plumbagin from Plumbago indica root to represent lab-scale and industrial-scale productions, respectively. The complexes from these two techniques can prevent the loss of plumbagin up to three-folds better than plumbagin in free form. The preservation by encapsulation can increase the remaining plumbagin from 22.68 to 60.26% after exposure at 50 °C for 6 weeks.