Assessment of particulate matter inhalation during the trip process with the considerations of exercise load.

A Particulate Matter (PM) inhalation model considering exercise load is established to evaluate the impact of PM on residents' travel health. The study chooses PM detectors to collect PM concentrations at the various transportation space, including walking, bicycle, bus, taxi, and subway. A multiple linear regression model revised by road greening is utilized to study the influence factors that have a potential impact on the PM concentration. The air inhalation model with the consideration of exercise load can be acquired by connecting the heart rate (HR) and individual characteristics. The PM2.5 and PM10 inhalation for a complete trip of traveler can be estimated using the proposed model based on air inhalation per time unit, travel time, and PM concentration. The analysis results using the experimental data in Xi'an indicate that PM concentrations in taxi carriage, bus carriage, and subway carriage are significantly different from those obtained from environmental monitoring stations. However, the difference is not significant in the locations of sidewalk, non-motorized lane, taxi station, bus station, subway concourse, and subway platform. PM concentration and humidity in background environment have a positive influence on the increase of PM concentration in transportation environment, while temperature and wind speed are negative. The mean values of air inhalation per time unit for male and female using each mode are in the range of 9.6-26.8 L/min and 9.8-27.8 L/min, respectively. Exposure time in non-motorized transportation has a large effect on PM inhalation of travelers, walking connections and waiting in motorized transportation are the main contributing states to PM inhalation of travelers. The results of the study can be used to predict travelers' PM inhalation in completed trips, and provide recommendations for travelers to choose a healthier mode.

Differences in the catalytic properties of Fe isotopes.

The significant differences in the catalytic properties caused by different 'isotopic catalysts' were discovered for the first time. The commonly purchased Fe2O3 is a 'mixture' of different Fe isotopic oxides which means the catalytic effect of Fe2O3 is theoretically a synthetical result of all isotopic compounds. In this work, the differences in catalytic properties of α-Fe2O3 with natural abundance ratio and separated isotopic α-Fe2O3 (α-54Fe2O3, α-56Fe2O3, and α-58Fe2O3) catalyzing thermal decomposition of ammonium perchlorate (AP) were investigated, and are mainly attributed to the difference in the charge distribution of the nuclei of different iron isotopes. The result suggests that isotope effects in different isotopes when utilized as catalysts are caused by nuclear morphology and the nuclear charge distribution. This study will serve as a base as well as an initiation for future studies of the isotopic catalyst.

Formation of a PVP-protected C/UO2/Pt catalyst in a direct ethanol fuel cell.

In order to solve the problem that UO2 in direct ethanol fuel cell anode catalysts is easily lost in acidic solution, resulting in the degradation of catalytic performance, this paper prepared a C/UO2/PVP/Pt catalyst in three steps by adding polyvinylpyrrolidone (PVP). The test results by XRD, XPS, TEM and ICP-MS showed that PVP had a good encapsulation effect on UO2, and the actual loading rates of Pt and UO2 were similar to the theoretical values. When 10% PVP was added, the dispersion of Pt nanoparticles was significantly improved, which reduced the particle size of Pt nanoparticles and provided more ethanol electrocatalytic oxidation reaction sites. The test results by electrochemical workstation showed that the catalytic activity as well as the stability of the catalysts were optimized due to the addition of 10% PVP.

Research on UO2 modification of a direct ethanol fuel cell Pt/C catalyst.

Radioactive UO2 powder was prepared by hydrothermal method and a set of Pt-xUO2/C catalysts were synthesized by impregnation method for solving the problem of low activity and easy poisoning of anode Pt/C catalysts for a direct ethanol fuel cell. XRD, TEM, EDS, XPS and ICP-MS characterization showed the successful loading of Pt and UO2 onto the carbon carrier. Electrochemical workstation and single cell test results confirm that the catalytic performance of Pt-10% UO2/C is significantly better than Pt/C-eg. It is speculated that the synergistic effect of Pt and U enhances the catalytic activity and UO2 improves the resistance to CO poisoning by releasing O2 stored in the lattice space, while the α-particles released by 235U can also generate radiolysis product OH and promote the oxidative desorption of CO from the Pt surface.

Improved performance of self-reactivated Pt-ThO2/C catalysts in a direct ethanol fuel cell.

A novel self-reactivated catalyst Pt-ThO2/C was prepared for the first time by selecting radioactive material ThO2 as the catalytic additive to address the low activity and toxicity of the anode Pt/C catalyst in a direct ethanol fuel cell. The catalytic activity and resistance to CO poisoning of Pt-6.67 wt%ThO2/C were found to be superior to those of Pt/C-NaBH4 in electrochemical workstation and single-cell tests. It is speculated that the exist of ThO2 not only improves the catalytic activity via the synergistic effect of Pt and Th, but also produces a large amount of radiolysis products, OH radicals, due to 232Th which oxidatively desorbs CO from Pt-COads and solves the CO poisoning problem.