Environmental-friendly extraction of di(2-ethylhexyl) phthalate from poly(vinyl chloride) using liquefied dimethyl ether.

Poly(vinyl chloride) (PVC) is one of the most widely used plastics. However, a major challenge in recycling PVC is that there is no economical method to separate and remove its toxic phthalate plasticizers. This research made a breakthrough by extracting PVC with liquefied dimethyl ether (DME) and successfully separating the plasticizer components. Nearly all (97.1 %) of the di(2-ethylhexyl) phthalate plasticizer was extracted within 30 min by passing liquefied DME (285 g) through PVC at 25 °C. The compatibility of PVC with organic solvents, including liquefied DME, was derived theoretically from their Hansen solubility parameters (HSP), and actual dissolution experiments were conducted to determine the optimal PVC solvents. A liquefied DME mixture was used to dissolve PVC, and the extract was diluted with ethanol to precipitate the dissolved PVC. We demonstrated that liquefied DME is a promising method for producing high quality recycled products and that the process retains the fundamental properties of plasticizers and PVC without inducing degradation or depolymerization. Because of its low boiling point, DME can be easily separated from the solute after extraction, allowing for efficient reuse of the solvent, extracted plasticizer, and PVC. DME does not require heat and produces little harmful wastewater, which significantly reduces the energy consumption of the plasticizer additive separation process.

CFD simulation of CVD reactors in the CH3SiCl3(MTS)/H2 system using a two-step MTS decomposition and one-step SiC growth models.

In this study, we report on a computational fluid dynamics (CFD) simulation of the chemical vapor deposition reactor of silicon carbide (SiC) in the methyltrichlorosilane (MTS, CH3SiCl3)/H2 system. The formation of SiC thin film is controlled by various process parameters, such as temperature and pressure. In this study, we propose a reaction mechanism of MTS decomposition to SiC growth on a substrate surface for CVD reactors in the CH3SiCl3(MTS)/H2 system. The reaction mechanism has two gas-phase pyrolysis reactions and one SiC film formation reaction. However, we individually build and validate MTS decomposition and SiC growth models to reduce uncertainty. An in-house version of reactingFoam, a reactive flow solver within OpenFOAM v2006, was used as the simulation tool. Our model accurately reproduced MTS decomposition for T = 1100-1350 K and [H2]/[MTS] = 2.65-14 at p = 101,325 Pa. Then, the MTS decomposition model was coupled with the SiC growth model, and the coupled model was applied to the SiC deposition data. The model could reproduce multiple datasets through validation studies.

Aeromedical Transport Operations Using Helicopters during the 2016 Kumamoto Earthquake in Japan.

More than 6,000 people died in the Great Hanshin (Kobe) Earthquake in 1995, and it was later reported that there were around 500 preventable trauma deaths. In response, the Japanese government developed the helicopter emergency medical service in 2001, known in Japan as the "Doctor-Heli" (DH), which had 46 DHs and 2 private medical helicopters as of April 2016. DHs transport physicians and nurses to provide pre-hospital medical care at the scene of medical emergencies. Following lessons learned in the Great East Japan Earthquake in 2011, a research group in the Ministry of Health, Labour and Welfare developed a command and control system for the DH fleet as well as the Disaster Relief Aircraft Management System Network (D-NET), which uses a satellite communications network to monitor the location of the fleet and weather in real-time during disasters. During the Kumamoto Earthquake disaster in April 2016, 75 patients were transported by 13 DHs and 1 private medical helicopter in the first 5 days. When medical demand for the DHs exceeded supply, 5 patients, 8 patients, and 1 patient were transported by Self-Defense Force, Fire Department, and Coast Guard helicopters, respectively. Of the 89 patients who were transported, 30 (34%) had trauma, 3 (3%) had pulmonary embolisms caused by sleeping in vehicles, and 17 (19%) were pregnant women or newborns. This was the first time that the command and control system for aeromedical transport and D-NET, established after the Great East Japan Earthquake in 2011, were operated in an actual large-scale disaster. Aeromedical transport by DHs and helicopters belonging to several other organizations was accomplished smoothly because the commanders of the involved organizations could communicate directly with each other in person within the Aviation Coordination Section of the prefectural government office. However, ongoing challenges in the detailed operating methods for aeromedical transport were highlighted and include improving shared knowledge and training across the organizational framework. These are particularly important issues to address given the Nankai Trough and Tokyo inland earthquakes that are predicted for the near future in Japan.

Shear Viscosity and Heterogeneous Structure of Alkylaminoethanol-Based CO2 Absorbents.

Shear viscosity of concentrated aqueous solutions of alkylaminoethanols was determined with changing the length of the alkyl chain and the concentration of dissolved CO2. The viscosity increased with increasing the CO2 loading, reflecting the strengthening of the intermolecular electrostatic interaction. The dependence of the viscosity on both temperature and CO2 loading was described by a modified version of Vogel-Fulchar-Tammann equation. Compared at the same volume concentration of CO2, the viscosity increased with increasing the alkyl chain lengths, and the dependence on the alkyl chain length increased with the CO2 loading. At the same time, small-angle X-ray scattering profiles exhibited the presence of a prepeak when the alkyl chain was long, and the prepeak grew with the CO2 loading. It suggests that the presence of the heterogeneous structure increases the shear viscosity of the CO2 absorbents when the alkyl chain is long.

Production of 5-hydroxymethylfurfural from corn stalk catalyzed by corn stalk-derived carbonaceous solid acid catalyst.

A carbonaceous solid acid was prepared by hydrothermal carbonization of corn stalk followed by sulfonation and was characterized by FT-IR, XRD, SEM and elemental analysis techniques. The as-prepared corn stalk-derived carbonaceous solid acid catalyst contained SO3H, COOH, and phenolic OH groups, and was used for the one-step conversion of intact corn stalk to 5-hydroxymethylfurfural (5-HMF) in the ionic liquid 1-butyl-3-methyl imidazolium chloride ([BMIM][Cl]), where a 5-HMF yield of 44.1% was achieved at 150 °C in 30 min reaction time. The catalytic system was applicable to initial corn stalk concentration of up to ca. 10 wt.% for the production of 5-HMF. The synthesized catalyst and the developed process of using corn stalk-derived carbon catalyst for corn stalk conversion provide a green and efficient strategy for crude biomass utilization.

Efficient laser performance of Nd:GdVO4 crystals grown by the floating zone method.

Efficient laser performance is demonstrated with Nd:GdVO4 crystals grown by the floating zone method. With a 2-at. % Nd-doped crystal a slope efficiency of 67% is achieved with pumping at 808 nm. We also find that pumping at 879 nm with a bandwidth of 1.8 nm is practical for laser diode pumping. With this pumping level the slope efficiency reaches 78%. High-quality Nd:GdVO4 crystals are successfully grown with as much as 15-at.% Nd concentration by the floating zone method without inclusions or macroscopic defects. Homogeneity and high reproducibility of crystal growth are confirmed.