No abstract

Simulation methods have become an important tool to reveal radionuclide migration during accidental radionuclide releases and predict influences of accidents on the marine environment. The instantaneous point source model is a useful method to simulate the large-scale radionuclide diffusion in marine areas. However, the simulation accuracy of this method requires improvement as it didn't take radionuclide decay into account. In this study, an improved instantaneous point source model considering radionuclide decay was proposed on the basis of the original model. Furthermore, the instantaneous point source model and the improved version were used to simulate the concentrations of 131I and 137Cs following the Fukushima Dai-ichi nuclear power plant accident. The results showed that the relative error of 131I concentrations decreased from 200.07% to 34.12% when using the improved model; and improvements in relative errors for 137Cs concentrations were not apparent as the simualtion period was much shorter than its half-life period. Therefore, the improved model can accurately simulate the diffusion process for radionuclides following an accident and provides an efficient decision support tool for risk assessment managers and for use in safety guarantees of nuclear power plants during siting and operational phases.

The transportation system promotes the development of the metropolitan area, while the number of vehicles in the transportation system is increasing, and the speed of energy consumption is also increasing. The consequences are not only the destruction of human living environment, but also many urban problems such as traffic congestion and urban environmental pollution for people living in the metropolitan area. In order to solve these problems, the article proposes a design scheme for urban public transport from the perspective of energy conservation. Through the modular design method, combined with the existing electric vehicle drive technology, the public transport is divided into two modules: the ride module and the drive module; at the same time, the existing traffic information service system is integrated to construct service system of the information guide to support the public transport scheme. The public transport design provides a possible solution to environmental pollution and traffic congestion.

A new X-by-wire system named Electronic Hydraulic Brake (EHB) System is designed in this paper, which can establish for smooth control of wheel cylinder hydraulic pressure. In this new EHB system, the electronic unit can supply flexible control, and at the same time, the hydraulic unit provides high power needed by the brake system. This brake system has high potential to add functional enhancements with proper modifications of software, such as ABS, VSC, TRC and ESP. This brake system is expected to become the core technology for further improving the vehicle stability.

Plant essential oils have good antimicrobial properties, but their poor stability and compatibility in aqueous solutions greatly limit their practical application. To address this issue, a dynamically crosslinked nanoemulsion based on host–guest assembly was developed in this study. First, a β-cyclodextrin-functionalized quaternary ammonium surfactant (β-CD-QA) and adamantane-terminated polyethylene glycol (APA) crosslinker were first synthesized. Then, the oil-in-water host–guest crosslinked nanoemulsions (HGCTNs) were formed by incorporating tea tree essential oils (TTO) as a natural antimicrobial agent. The results showed that HGCTNs significantly improved the stability of the essential oil nanoemulsions and extended their shelf life. Furthermore, HGCTNs demonstrated effective antimicrobial properties against both Gram-negative/positive bacterioplankton and bacterial biofilms. The results of antibacterial experiments showed that the dynamically crosslinked HGCTNs exhibit superior antibacterial efficacy, with a minimum inhibitory concentration (MIC) of 12.5 v/v % (0.13 μL/mL TTO) and could eradicate the biofilms. The electrical conductivity of the bacterial solution gradually increased within 5 h of treatment with the nanoemulsions, indicating that the HGCTNs have a slow-release effect of TTO and sustainable antibacterial ability. The antimicrobial mechanism can be attributed to the synergistic antibacterial action of the β-CD-QA surfactant containing a quaternary ammonium moiety and TTO, which are stabilized by nanoemulsions.