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The purpose of this paper is to develop porous nitrogen-enriched carbon (NC-U) with high nitrogen concentration and high specific capacitance (Cpe) as the electrode material for supercapacitors.

NC-U was obtained by carbonization of polyvinylpyrrolidone/melamine formaldehyde resin (PVP/MF) with different contents of urea. In comparison, NC-K was also prepared by the KOH activation method. A series of asymmetric supercapacitors with NC as a negative electrode was assembled. The composition, microstructure and electrochemical properties of NC and their supercapacitors were studied.

The results show that NC-U shows irregular particles with a porous honeycomb structure. High Cpe was obtained for urea-treated NC-U because of the improvement of nitrogen, conductivity and specific surface area (S _BET ). NC-U50 with 13.15 per cent at nitrogen has the highest Cpe of 148.53 F/g because of the highest concentration of N-6 and N-5. NC-K with higher S _BET has lower Cpe than NC-U50 because of its lower nitrogen concentration. When the specific power of the supercapacitor with NC-U50 as a negative electrode is 1,565.56 W/kg, its specific energy is still 4.35 Wh/kg. There is only 5.9 per cent decay in Cpe over 1,000 cycles.

NC-U is a suitable electrode material for supercapacitors, which can be used in the field of electric vehicles to solve the problems of energy shortage and environmental pollutions.

Porous NC-U based on PVP/MF/urea composites with high nitrogen concentration and Cpe is novel, and it owns good electrochemical properties.

Diffusion treatments may comprise the diffusion of interstitial elements such as oxygen, nitrogen, carbon, or boron into the surface from a gaseous or molten salt bath environment, or less commonly it may consist of substitutional diffusion of a previously deposited metal coating or by packing in materials such as ferromanganese or chromium with suitable additives.

The purpose of this study is to select a proper surface treatment to enhance wear resistance of engine camshafts. The camshaft is a relevant part of a diesel engine which works under torsion, fatigue and wear efforts. They are usually manufactured by casting, forging or machining from forged bar of low alloy steels, and in most cases, the machined surfaces are quenched and tempered by induction heating. After that, in many cases, to withstand the efforts imposed on the active surfaces and improve tribology and fatigue properties, the industry used for decades, thermochemical technologies such as salt bath or gaseous nitriding and nitrocarburizing processes.

This paper studied the effects of plasma nitriding and plasma nitrocarburizing, on the tribological behaviour of the steel SAE 1045HM3 proposed to produce camshafts. After the plasma treatments, the change in surface roughness was measured; the modified layers were studied by X-ray techniques and its thickness by optical microscopy. The diffusion zone was evaluated by Vickers microhardness determinations. Tribology tests were performed by pin-on-disc configuration using WC ball as a counterpart.

Results show that plasma nitrided samples present the best tribological behaviour compared with the nitrocarburized ones; also, the influence of the roughness produced by the thermochemical processes appears to be important.

Although both the plasma treatments have been applied for many years, and also reported separately in the scientific literature, there was no information comparing these two treatments for carbon steels, and also, there is not much about tribology in lubricated conditions of nitrided and nitrocarburized carbon steels. In fact, it is not proved that the porosity of the nitrocarburized layer is beneficial for wear resistance in lubricated conditions. In this paper, it was proved that at least in the tested conditions, it is not.

Gas or plasma nitrocarburizing is usually recommended for this kind of applications, although the modified layer is porous. This paper attempts to prove that nitriding could be better than nitrocarburizing, even with a thinner white layer.

Polyurethane (PUR) foam parts are traditionally manufactured using metallic molds, an unsuitable approach for prototyping purposes. Thus, rapid tooling of disposable molds using fused filament fabrication (FFF) with polylactic acid (PLA) and glycol-modified polyethylene terephthalate (PETG) is proposed as an economical, simpler and faster solution compared to traditional metallic molds or three-dimensional (3D) printing with other difficult-to-print thermoplastics, which are prone to shrinkage and delamination (acrylonitrile butadiene styrene, polypropilene-PP) or high-cost due to both material and printing equipment expenses (PEEK, polyamides or polycarbonate-PC). The purpose of this study has been to evaluate the ease of release of PUR foam on these materials in combination with release agents to facilitate the mulding/demoulding process.

PETG, PLA and hardenable polylactic acid (PLA 3D870) have been evaluated as mold materials in combination with aqueous and solvent-based release agents within a full design of experiments by three consecutive molding/demolding cycles.

PLA 3D870 has shown the best demoldability. A mold expressly designed to manufacture a foam cushion has been printed and the prototyping has been successfully achieved. The demolding of the part has been easier using a solvent-based release agent, meanwhile the quality has been better when using a water-based one.

The combination of PLA 3D870 and FFF, along with solvent-free water-based release agents, presents a compelling low-cost and eco-friendly alternative to traditional metallic molds and other 3D printing thermoplastics. This innovative approach serves as a viable option for rapid tooling in PUR foam molding.

THE problem of the dissipation and transfer of heat is one that is becoming of increasing importance in aircraft with the introduction of gas‐turbines and jet propulsion as well as in view of the prospects of flight at high altitudes. We are therefore printing below summaries of all the papers read at the recent Anglo‐American conference on the subject, although some of them are not directly concerned with aeronautical applications.

Over 3,000 scientists, technologists and industrialists attended the 1955 World Petroleum Congress, held in Rome, Italy, from June 6 to 17. Delegates representing 45 countries read papers covering all aspects of the petroleum industry, including geology and geophysics, drilling and production, oil processing, the production of chemicals from petroleum, the composition of petroleum, utilisation of petroleum products, and other more general subjects. Abstracts of papers included in the corrosion section are given below, and these discuss problems of graphite formation, the occlusion of hydrogen, static electricity, and corrosion inhibition in refinery equipment.

The purpose of this article is to determine if the level of recyclability of atomized Ti-6Al-4V powder, used as raw material in electron beam melting (EBM), is in compliance with aeronautical standards.

The adopted strategy for this study was to manufacture a series of builds in the EBM system recycling the same powder from build to build. Optimized EBM process parameters were used, as well as the common procedure of powder recycling for each build, to emulate real production conditions. The aim of the study is to confirm that the powder properties are kept within the range of chemical contents which complies with the aeronautical standards despite numerous reuses.

The conclusion of this study is that the EBM-processed Ti-6Al-4V powder properties are conserved in consecutive builds with recycled powder. This study shows that significant raw material can be saved by powder recycling since the powder quality is kept in range throughout consecutive builds, despite the working conditions of EBM.

The main two advantages of application of EBM in the aerospace sector are design freedom and reduction of buy-to-fly ratio. The design freedom enables the creation of lightweight structures, which can significantly reduce the fuel consumption, while the reduction of buy-to-fly ratio enables much material saving in manufacturing of aircraft parts.

The present study represents the first complete study on atomized Ti-6Al-4V powder processed in EBM which was made for the sake of aeronautical sector.

DESPITE the quite extensive literature on foam, the mechanism of its formation and decay does not appear to be widely appreciated. Most fundamental research has been orientated towards maximum foam in aqueous solutions, whereas the desire in aircraft engines is for minimum foam in oil ‘solutions’. Further, the numerical results obtained experimentally depend on the details of experimental procedure, which makes correlation of existing data very uncertain.

The purpose of this paper is to introduce bio-inspired FeN₄-S-C black nano-electrocatalyst for the oxygen reduction reaction (ORR) in an alkaline medium. The FeN₄-S-C derived without pyrolysis of precursors in high temperature is recognized as a new electrocatalyst for the ORR in an alkaline electrolyte. For the proper design of bio-inspired nano-electrocatalyst for the ORR performance, chlorinated iron (II) phthalocyanine nanoparticles were used as templates for achieving the active sites in aqueous KOH by rotating disk electrode methods. The most active FeN₄-S-C catalyst exhibited a remarkable ORR activity in the alkaline medium. The objectives of this paper are to investigate the possibility of nanoscale particles size (Ëœ5nm) of electrocatalyst, to achieve four-electron transfer mechanism and to exhibit much superior catalytic stability in measurements. This paper will shed light on bio-inspired FeN₄-S-C materials for the ORR catalysis in alkaline fuel cells.

The paper presents a new bio-inspired nano-electrocatalyst for the ORR, which has activity nearby platinum/carbon electrocatalyst. Chlorinated iron phthalocyanine nanoparticles have been used as FeN₄ template, which is the key point for the ORR. Bio-inspired nano-electrocatalyst has been fabricated using chlorinated iron phthalocyanine, sodium sulphide and carbon black.

The particles’ size was 5 nm and electron transfer number was 4.

The catalyst that is used in this method should be weighed carefully. In addition, the solvent should be a saturated solution of NaCl in water.

The method provides a simple and practical solution to improving the synthesis of iron-based catalyst for ORR.

The method for the synthesis of bio-inspired electrocatalyst was novel and can find numerous applications in industries, especially as ORR non-precious metal catalyst.

The purpose of this paper is to develop a corrosion resistant zinc‐free coating for interstitial free steel.

The objective was achieved by developing a titania‐silica hybrid coating through a sol‐gel process by incorporating a dye molecule. The role of dye molecules was particularly important for enhancing the anti‐corrosion properties of the coating. The approach of current research was to develop a low‐temperature coating process that can bring similar performance to that obtained in case of zinc coating. Titania and silica precursors were mixed by stirring under a nitrogen atmosphere at 80°C to formulate a low‐temperature coating. The dye molecules were added before addition of water for subsequent hydrolysis. This complete formulation was applied over steel sheets using a roll coater as the application method.

The ranking order of improved corrosion resistance was found to be PATMS>EETMS>GPTMS and the addition of trace amount of tartrazine dye (60‐65 mg/l of liquid) in PATMS increased the corrosion service life in saline environments from 168 to 216 h, thus showing a promising improvement. Scanning Kelvin Probe results indicated that the corrosion reaction is controlled cathodically in presence of dye and, electrochemical impedance spectroscopy results exhibited a charge transfer resistance (Ct) of coating with dye of 419Ω cm², which was higher than that of a similar coating without dye (360Ω cm²), indicating increased corrosion protection.

This coating had improved barrier protection but lacked cut edge protection. Future work will focus on adding sacrificial protection by introducing compatible corrosion inhibitors, especially dye molecules, which are photosensitive.

This coating has huge potential for use in the automotive sector, especially for certain automotive parts (i.e. helm flanges), which suffer from poor durability in salty and high‐humidity atmospheres.

Since this coating formulation utilises a partially aqueous base, some environmental impact cannot be avoided, but it will have less impact than a complete solvent base formulation.

The novelty of the work was the introduction of dye molecules as the corrosion inhibitor and their compatibility in the hybrid coating system.