Ni@onion-like carbon and Co@amorphous carbon: Control of carbon structures by metal ion species in MOFs

We first report the facile synthesis of metal–carbon composites consisting of metal nanoparticles (NPs) and different types of carbon species: onion-like and amorphous carbon, Ni@onion-like carbon and Co@amorphous carbon. By...

Carbides and Carbon Control in MC – Reinforced Superalloys

Polycrystalline alloys based on cobalt and elaborated by classical foundry are known since the middle of the last century. They are currently still used, notably for geometrically complex components working at high temperature. Beyond the oldest ones reinforced by chromium carbides, new principles of carbides–strengthened cobalt–based alloys have recently appeared. MC–type refractory mono–carbides allow maintaining the melting start temperature at a high level when they are present as single carbide phase. Their high temperature stabilities and script–like morphologies also favor high mechanical properties at elevated temperatures. Optimized MC–carbides fractions can be obtained with carbon contents, close to 0.4 wt.%C, for achieving significant strengthening without threat for the low and high temperature toughness. Controlling the carbon content is thus of prior importance. Unfortunately the most common metallographic apparatus used for measuring the chemical composition of alloys – the Energy Dispersion Spectrometers (EDS) attached to Scanning Electrons Microscopes (SEM) – are not able to analyze, with sufficient accuracy, carbon with so low contents. A simple indirect method using both EDS and SEM is proposed here to get some information about the carbon content in several MC–reinforced Co–based superalloys.

A Prediction Method of GHG Emissions for Urban Road Transportation Planning and Its Applications

The increasing vehicle usage has brought about a sharp increase in greenhouse gas (GHG) emissions of vehicles, which brings severe challenges to the sustainable development of road transportation in Chinese counties. Low-carbon transportation planning is an essential strategy for carbon control from the source of carbon emissions and is crucial to the full transition to a low-carbon future. For transportation planning designers, a quick and accurate estimation of carbon emissions under different transportation planning schemes is a prerequisite to determine the optimal low-carbon transportation development plan. To address this issue, a novel prediction method of hourly GHG emissions over the urban roads network was constructed in this paper. A case study was conducted in Changxing county, and the results indicate the effectiveness of our proposed method. Furthermore, we applied the same approach to 30 other counties in China to analyze the influencing factors of emissions from urban road networks in Chinese counties. The analysis results indicate that the urban road mileage and arterial road ratio are the two most important factors affecting road network GHG emissions in road traffic planning process. Moreover, the method was employed to derive peak hour emission coefficients that can be used to quickly estimate daily or annual GHG emissions. The peak hour emission of CO2, CH4, and N2O accounts for approximately 9–10%, 8.5–10.5%, 5.5–7.5% of daily emissions, respectively. It is expected that the findings from this study would be helpful for establishing effective carbon control strategies in the transportation planning stage to reduce road traffic GHG emissions in counties.