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.

Durability of nano-enhanced textiles through the life cycle: releases from landfilling after washing

Abstract: By taking a life cycle approach to study the potential for silver nanoparticle (AgNP) release from functionalized textiles, we can estimate the relative importance of different phases to the release of Ag over time. Alongside the fastness of the AgNPs during the use phase (e.g. washing), we further explored the release potential of NPs from fabrics disposed of in a landfill (i.e. the end of life stage). Three different laboratory-prepared nano-enhanced fabrics (60 nm and 100 nm citrate-capped Ag as reactive particles; 60 nm citrate-capped Au as a non-reactive control) were subjected to 1 or 10 washing cycles under different laundering conditions (detergents with and without oxidants). The total metal released varied significantly depending on NP incorporation and the washing pattern variant. Au served to contrast the mechanical release of NPs with the (additional) chemical release the detergents induced to the Ag textiles, where the Ag : Au ratio released from the fabric was as high as 3, suggesting more predominant chemical mechanisms for silver release in those cases. Textile disposal was simulated by the Toxicity Characteristic Leaching Procedure (TCLP), where pre-laundered fabrics were subjected to this sequential exposure. The results show that the active landfill environment cannot readily mobilize the NPs from the fabric surface as easily after washing compared to unwashed textiles. Without washing, simulated landfilling released between 35–45% of the total Ag incorporated into the fabric (and only 20% of Au), but after laundering, most variants released less than 0.5%. Therefore, larger releases of NPs from textiles were observed during the use phase of the life cycle rather than the disposal phase, where an important portion of the released NP was in the dissolved phase. Large variations in releases at the end of life stage are determined under pre-washing conditions, which proves the necessity of life-cycle aging sequences to properly assess the likelihood and characteristics of materials released from nano-enhanced textiles.

Comparison and mechanism of photocatalytic activities of N-ZnO and N-ZrO2 for the degradation of rhodamine 6G

Abstract: N-doped ZnO (N-ZnO) and N-doped ZrO2 (N-ZrO2) are synthesized by novel, simple thermal decomposition methods. The catalysts are evaluated for the degradation of rhodamine 6G (R6G) under visible and UV light. N-ZnO exhibits higher dye degradation under both visible and UV light compared to N-ZrO2 due to possessing higher specific surface area, lower crystalline size, and lower band gap. However, it is less reusable than N-ZrO2 and its photocatalytic activity is also deteriorated at low pH. At the same intensity of 3.5 W/m(2), UVC light is shown to be a better UV source for N-ZnO, while UVA light is more suitable for N-ZrO2. At pH 7 with initial dye concentration of 10 mg/L, catalyst concentration of 1 g/L, and UVC light, 94.3 % of R6G is degraded by N-ZnO within 2 h. Using UVA light under identical experimental conditions, 93.5 % degradation of R6G is obtained by N-ZrO2. Moreover, the type of light source is found to determine the reactive species produced in the R6G degradation by N-ZnO and N-ZrO2. Less oxidative reactive species such as superoxide radical and singlet oxygen play a major role in the degradation of R6G under visible light. On the contrary, highly oxidative hydroxyl radicals are predominant under UVC light. Based on the kinetic study, the adsorption of R6G on the catalyst surface is found to be the controlling step.

Approach to measure the mix response flexibility of manufacturing systems

Abstract: The mix response flexibility of a manufacturing system is the ability to change between product types quickly and economically. This paper proposes a new approach to measure this flexibility in terms of both capability and capacity. While the processing capability is represented as the number of operations that the machines can perform, the manufacturing capacity is modelled as the efficiency of different machines. The proposed model is applied to measure the mix response flexibility for both single and multiple machine systems.