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The purpose of the research is to concentrate on the most important smart metropolitan applications which are smart living, smart security and smart maintainable. In that, Power management and security is a most important problem in the current metropolitan situation.

A smart metropolitan area utilizes recent innovative technologies to improve its living, security and maintainable. The aim of this study is to recognize and resolve the difficulties in metropolitan area applications.

The main aim of this study is to reduce the metropolitan foremost energy consumption, to recharge the electric vehicles and to increase the lifetime of smart street lights.

The hybrid renewable energy street light applies smart resolutions to substructure and facilities in rural and metropolitan areas to create them well. This study will be applying smart metropolitan solar and wind turbine street light using renewable energy for existing areas. In future, the smart street light work will be implemented everywhere else.

The purpose of this paper is to conduct the synthesization of LiFePO₄-C (LFP-C) with fine particle size and enhanced electrochemical performance as the positive electrode material for Li-ion capacitors (LICs) with neutral aqueous electrolyte.

LFP-C was prepared by using polyethylene glycol (PEG) as a grain growth inhibitor, and the effects of the calcination temperature and PEG content on the structure and morphology of LFP-C were investigated. LICs using environment-friendly, safe and low-cost LiNO₃ aqueous electrolyte were assembled with LFP-C as the positive electrode and active carbon as the negative electrode. The electrochemical performances of LFP-C and LICs were studied.

The results show that the particle size of LFP-C decreases significantly through the introduction of PEG. Cyclic voltammetry results show that the LFP-C prepared at 550°C with 1.0 g PEG exhibits the highest C_pe of 725 F/g at the scanning rate of 5 mA/s. Compared to LFP prepared without PEG, the electrochemical performance of optimized LFP-C dramatically increases due to the decrease of the particle size. Moreover, the LIC assembled with the optimized LFP-C exhibits excellent electrochemical performances. The LIC maintains about 91.3 per cent of its initial C_ps after 200 cycles which shows a good cycling performance.

The LFP-C is the suitable positive electrode material for LICs with neutral aqueous electrolyte. LICs can be used in the field of automobiles and can solve the problems of energy shortage and environmental pollution.

Both the LFP-C with fine particle size and its optimal LIC using environment-friendly, safe and low-cost LiNO₃ aqueous electrolyte own good electrochemical performances.

The purpose of this paper is to synthesize a new kind of conductive grease which possesses a prominent conductive capacity and good tribological properties.

A two-step method was used to prepare complex lithium-based grease. Ketjen black (KB), acetylene black (AB) and carbon black (CB) were characterized by transmission electron microscope and used as lubricant additives to prepare conductive greases. Conductive capacity was evaluated by a conductivity meter, a surface volume resistivity meter and a circuit resistance meter. Tribological properties were investigated by a reciprocating friction and wear tester (MFT-R4000). The worn surfaces were analyzed by a scanning electron microscope, Raman spectroscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscope.

The conductive grease prepared with KB has a prominent conductive capacity at room temperature, 100°C and 150°C. Further, this conductive grease also possesses better tribological properties than AB and KB greases. When the concentration of KB is 1.8 Wt.%, the coefficient of friction and wear width reduced by 11 and 14 per cent, respectively.

This work is a new application of nanometer KB as a lubricant additive in grease, which provides a direction for preparing conductive grease. The conductivity and tribology experiments have been carried out though the variation of experiment conductions.

This paper addressed some critical issues in the development of hybrid electric powertrains for aircraft and propose a design methodology based on multi-objective optimization algorithms and mission-based simulations.

Scalable models were used for the main components of the powertrain, namely, the (two stroke diesel) engine, the (lithium) batteries and the (permanent magnet) motor. The optimization was performed with the NSGA-II genetic algorithm coupled with an in-house MATLAB tool. The input parameters were the size of engine, the hybridization degree and the specification of the battery (typology, nominal capacity, bus voltage, etc.). The outputs were electric endurance, additional volume, performance parameters and fuel consumption over a specified mission.

Electric endurance was below 30 min in the two test cases (unmanned aerial vehicles [UAVs]) but, thanks to the recharging of the batteries on-board, the total electric time was higher. Fuel consumption was very high for the largest UAV, while an improvement of 11 per cent with respect to a conventional configuration was obtained for the smallest one.

The research used a simplified approach for flight mechanics. Some components were not sized in the proposed test cases.

The results of the test cases stressed the importance of improving energy density and power density of the electric path.

The proposed methodology is aimed at minimizing the environmental impact of aircraft.

The proposed methodology was obtained from the automotive field with several original contributions to account for the aircraft application.

This study aims to probe the applicability of 2-mercaptobenzothiazole (MBT) functionalized ionic liquids (ILs) as additives in lithium complex grease (LCG) by researching the corrosion inhibiting, rheological and tribological performances.

Electrochemical tests such as electrochemical impedance spectroscopy and potentiodynamic polarization curves were used on Gamry electrochemical workstation to research the corrosion inhibition properties of ILs in 1.0 M HCl corrosive solution. The rheological properties of different grease samples were tested on a rheometer. The tribological properties were investigated on SRV-V oscillating reciprocating friction and wear tester. Scanning electron microscope, X-ray spectrometer and X-ray photoelectron spectrometer were used to characterize the lubricating mechanism.

The 2-MBT functionalized ILs have excellent corrosion inhibition properties. When used as additives in LCG, they both exhibited enhancing effects on thermostability, colloid stability and structural recoverability, and furthermore, outstanding friction-reducing and antiwear properties were also obtained. Surface analysis indicated that the superior lubricating performances of 2-MBT functionalized ILs were mainly ascribed to the formation of tribochemical products on wear tracks, including organic compounds with C–O bond, Fe₂O₃ and FeS₂.

The 2-MBT-based ILs synthesized in this study were multifunctional additives with excellent corrosion inhibiting and tribological properties, which would have a very broad application prospect in lubricating grease industry.

The purpose of this study is to design a new type of cold plate to improve the thermal performance of liquid-cooled thermal management system of lithium-ion batteries.

A cold plate with leaf type channels is proposed to enhance the cooling performance. Effects of the leaf type channel parameters (i.e. channel angle 20°, 40°, 60°, 80°; coolant mass flow rate 0.25 × 10^–3, 0.50 × 10^–3, 0.75 × 10^–3, 1.00 × 10^–3, 1.25 × 10^–3 kg·s⁻¹; channel number 1, 3, 5, 7) on the performance are numerically investigated by using a 3D mathematical model.

Compared to the traditional I type channels, the leaf type channels have better cooling performance. It is found that the battery temperature variation and channel pressure drop are decreased with decreasing channel angle and increasing channel number. In addition, the cooling performance can be improved by increasing the coolant mass flow rate.

This study can provide guidance for the development of novel effective cold plates.

The design of cold plates with leaf type channels can be used in liquid-cooled thermal management system to reduce the battery temperature difference.

Lithium-polymer batteries have common usage in aviation industry especially unmanned aerial vehicles (UAV). Overheating is a serious problem in lithium-polymer batteries. Various cooling methods are performed to keep lithium-polymer batteries in the desired temperature range. The purpose of this paper is to examine pouch type lithium-polymer battery with plate fins by using particle image velocimetry (PIV) and computational fluid dynamics (CFD) for UAV.

Battery models were produced with a 3D printer. The upper surfaces of fabricated battery models were covered with plate fins with different fin heights and fin thicknesses. Velocities were obtained with PIV and CFD. Temperature dissipations were acquired with numerical simulations.

At the end of the study, the second battery model gave the lowest temperature values among the battery models. Temperature values of the seventh battery model were the highest temperatures. Fin cooling reduced the maximum cell temperatures noticeably. Numerical simulations agreed with PIV measurements well.

This paper takes into account two essential tools such as PIV and CFD, for fluid mechanics, which are significant in the aviation industry and engineering life.

The originality of this paper depends on investigation of both PIV and CFD for UAV and developing a cooling method that can be feasible for landing and take-off phases for UAV.

This study aims to investigate the synergistic friction reduction and antiwear effects of lyophilized graphene loading nano-copper (RGO/Cu) as lubricating oil additives, compared with graphene.

The friction performance of freeze-drying graphene (RGO) and RGO/Cu particles was investigated at different addition concentrations and under different conditions.

Graphene plays a synergistic friction reduction and antiwear effect because of its large specific surface area, surface folds and loading capacity on the nanoparticles. The results showed that the average friction coefficients of RGO and RGO/Cu particles were 22.9% and 6.1% lower than that of base oil and RGO oil, respectively. In addition, the widths of wear scars were 62.3% and 55.3% lower than those of RGO/Cu particles, respectively.

The RGO single agent is suitable for medium-load and high-speed conditions, while the RGO/Cu particles can perform better in the conditions of heavy load and high speed.

This paper aims to present a requirements analysis for the processing of water-based electrode dispersions in inkjet printing.

A detailed examination of the components and the associated properties of the electrode dispersions has been carried out. The requirements of the printing process and the resulting performance characteristics of the electrode dispersions were analyzed in a top–down approach. The product and process side were compared, and the target specifications of the dispersion components were derived.

Target ranges have been identified for the main component properties, balancing the partly conflicting goals between the product and the process requirements.

The findings are expected to assist with the formulation of electrode dispersions as printing inks.

Little knowledge is available regarding the particular requirements arising from the systematic qualification of aqueous electrode dispersions for inkjet printing. This paper addresses these requirements, covering both product and process specifications.

The purpose of this paper is to combine the entropy weight method with the cloud model and establish a fire risk assessment method for airborne lithium battery.

In this paper, the fire risk assessment index system is established by fully considering the influence of the operation process of airborne lithium battery. Then, the cloud model based on entropy weight improvement is used to analyze the indexes in the system, and the cloud image is output to discuss the risk status of airborne lithium batteries. Finally, the weight, expectation, entropy and hyperentropy are analyzed to provide risk prevention measures.

In the risk system, bad contact of charging port, mechanical extrusion and mechanical shock have the greatest impact on the fire risk of airborne lithium battery. The fire risk of natural factors is at a low level, but its instability is 25% higher than that of human risk cases and 150% higher than that of battery risk cases.

The method of this paper can evaluate any type of airborne lithium battery and provide theoretical support for airborne lithium battery safety management.

After the fire risk assessment is completed, the risk cases are ranked by entropy weight. By summarizing the rule, the proposed measures for each prevention level are given.