Efficient C-N coupling in electrocatalytic urea generation on copper carbonate hydroxide electrocatalysts

Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.

Driver-Centric Velocity Prediction With Multidimensional Fuzzy Granulation

Dear Editor,This letter deals with a real-world problem regarding chaotic time series prediction, where a driver-centric velocity prediction model is presented for vehicle intelligent control and advanced driver assistance,i.e., multi-dimension fuzzy predictor. Inspired by fuzzy granulation technology, a finite-state Markov chain(MC) is reinforced to capture probabilities of the transitions between velocity and acceleration and present signals that vary in a continuous range.

2-甲基呋喃及其与异辛烷掺混燃料喷雾的微观特性研究

第二代生物燃料2-甲基呋喃(MF)由于其独特的物理化学性质受到学者们的广泛关注,研究MF以及它的掺混燃料在不同条件下的雾化效果也显得尤为重要。利用相位多普勒技术(PDPA),在不同喷射压力、环境温度、环境背压下,研究了MF、异辛烷以及两者等体积掺混燃料MF50喷雾的粒径与速度分布规律。结果表明:测试燃料的喷雾粒径整体分布呈现油束中心大,两端小的对称分布。微粒速度随环境背压的增加而降低,并且在低背压下速度为双峰分布,高背压下则是单峰分布。随着环境背压的增大,异辛烷粒径不断增加,MF粒径先减小再增加。

Development of a Series Hybrid Electric Aircraft Pushback Vehicle: A Case Study

The work presented in this paper is a progression to previous research which developed an overcurrent-tolerant prediction model. This paper presents some of the modelling and development techniques used for the previous research, but more emphasis is placed on the requirements of the case study;whereby an aeroplane pushback tug is converted into a series Hybrid Electric Vehicle (HEV). An iterative design process enabled the traction motor, transmission, generator and battery pack parameters to be tailored for this vehicle’s unique duty cycle. A MATLAB/Simulink model was developed to simulate the existing internal combustion engine powertrain as well as the series HEV equivalent for comparative analysis and validation purposes. The HEV design was validated by comparing the simulation results to recorded real-world data collected from the existing vehicle (torque, speeds etc.). The HEV simulations provided greater fuel savings and reduced emissions over the daily duty cycle in comparison to the existing vehicle.

Recent Progress in Automotive Gasoline Direct Injection Engine Technology

Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.

Spray,atomization and combustion characteristics of oxygenated fuels in a constant volume bomb:A review

Biofuels have extensive available resources and have an immense potential as promising alternative fuels for automobile.The application advantages of biofuels are mainly reflected as particulate matter(PM)reduction,carbon neutral,greenhouse gases reduction,waste utilization,energy and economic security,and fuel pluralism.Based on the understanding of molecular structure effects of biofuels on soot formation and particles morphology,the effects of alcohols,ethers,esters and biodiesel on spray and combustion process in constant volume bomb in recent years are retrospectively analyzed in this paper.For the mixture,macromolecular ester fuels and polyoxymethylene dimethyl ether(PODE)are conducive to the improvement of liquid spray,while biodiesel,small molecules,dimethyl ether(DME)and alcohols are reversed.Alcohols are advantageous to the extension of mixing time and the increasing of vapor-phase mixture.Through the influence integrated assessment,alcohols show the best performance on the spray,atomization and combustion,while biodiesels show the worst.But in terms of combustion,PODE is the best choice without considering spray and atomization.For binary alternative-diesel fuel blends,methanol or butanol is the best additive based on synthetically considerations on spray,atomization and combustion.To meet the requirements of the fuel application of diesel engine,ternary fuel or even quaternary fuel have been proposed and explored.This review can help to form a systematic understanding on fuel recombining and obtain the guide of clean and efficient fuel formulation for diesel engine.

Feedstocks,environmental effects and development suggestions for biodiesel in China

In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change(LUC).Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions.The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type,the precipitation and the oil contents and the cultivation conditions of plants.Then,the suggestions for biodiesel development in China were given.Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land.Jatropha curcas(J.curcas),Pistacia chinensis Bunge(P.chinensis),Comus wilsoniana(C.wilsoniana)and Xanthoceras sorbifolium Bunge(X.sorbifolium)were considered as the most promising feedstocks for biodiesel production.It is suggested to plant X.sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China.The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater.The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants.Lastly,only natural gas-based or biomass-based methanol can be used for biodiesel production.

Experimental Investigation of the Rail Pressure Fluctuations Correlated with Fuel Properties and Injection Settings

Injection-induced rail pressure fluctuations are proven to cause nonuniform spray development.These fluctuations are also responsible for generating lower injection pressures,to the detriment of jet penetration length and break-up timing.Despite the vast literature dealing with such issues,several aspects of rail pressure fluctuations remain unclear.Additionally,the need for compliance with the emission legislation has shed light on the potential of alternative fuels,which represent a pathway for sustainable mobility.This scenario has motivated the present study dealing with the assessment of the time history of rail pressure correlated with fuel properties.Tests have been performed using a last-generation common rail injection equipment under various injection settings,employing diesel and 2-methylfuran-diesel blend.This paper describes the research activity and aims to provide new insights into the correlation of rail pressure fluctuations with fuel properties.