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To address modern tribological challenges—reducing friction and wear to conserve resources while minimising environmental impact—cobalt-doped DLC (Co-DLC) coatings were developed. These nanometric multilayer coatings, designed to retain key properties such as hardness, reduced modulus, and substrate adhesion, were fabricated using non-reactive DC magnetron sputtering (DCMS). The multilayer structure was achieved by controlling the planetary substrate holder's rotational speed. Characterisation of microscopic, chemical, structural, and mechanical properties was performed using techniques including FEI-SEM, EDS, XRD, TEM, Raman spectroscopy, scratch adhesion testing, and nanoindentation. Tribological performance was evaluated under boundary and fully flooded lubrication using PAO4 base oil and formulations with ashless, sulphur-free AW and EP additives. The coatings exhibited a granular surface morphology, columnar cross-sections, and amorphous structure. Increased dopant concentrations slightly enhanced graphitisation and significantly improved adhesion, though hardness and reduced modulus decreased. Tribological testing revealed superlubricity in several coating–oil combinations and significantly reduced wear rates with higher dopant levels and new additives. A phosphate ester additive without an amine group achieved the lowest COF values, while one with an amine group yielded minimal wear rates. These findings highlight the potential of Co-DLC coatings and tailored additives to minimise friction and wear effectively. [ABSTRACT FROM AUTHOR]

With low friction and high hardness, diamond-like carbon (DLC) coatings are a prominent surface engineering solution for tribosystems in various applications. Their versatility stems from their varying composition, facilitated by different deposition techniques, which affect their properties. However, environmental impact is often overlooked in coating design. The objective of this paper is to assess the resource efficiency of four different common deposition techniques, thus identifying critical factors for sustainable DLC deposition. The coatings were deposited in one single chamber, enabling a direct comparison of the resource consumption of each technology. Expenditure of electric energy and consumables per volumetric output accounted for the environmental impact of manufacturing the coatings, which was evaluated across the indicators of damage to human health, damage to ecosystems, and resource scarcity. Electric energy use, dictated by deposition rate, was demonstrated to be the most significant factor contributing to the environmental impact. The environmental impact of PECVD and μW-PECVD was comparable and remarkably lower than that of dcMS and HiPIMS, the latter being the least energy efficient process, with the lowest output rate but highest energy expenditure. Thus, μW-PECVD could be considered the 'greenest' production method. These findings are consequential for coaters to efficiently produce good-quality DLCs with low environmental impact. [ABSTRACT FROM AUTHOR]

Hybrid electric air-ground vehicles (HEAGVs), which can run on the land and fly in the air, are considered a promising future transportation. The operation of HEAGVs, accompanied by high energy consumption, could lead to increasing battery temperature, which may affect the lifespan of the battery. To make the battery last longer and improve energy efficiency, an effective energy management strategy (EMS) is necessary for the operation of HEAGVs. In this regard, this paper proposes a predictive EMS based on model predictive control (MPC). Firstly, speed information is obtained by intelligent network technology to achieve a prediction of power demand, and then the state of charge (SOC) reference trajectory is planned. Secondly, a Pontryagin's minimum principle-based model predictive control (PMP-MPC) framework is proposed, including battery thermal dynamics. Under the framework, fuel efficiency is improved by reducing the temperature of the battery. Finally, the proposed method is compared to PMP, dynamic programming (DP), and rule-based (RB) methods. The effect of different preview horizon sizes on fuel economy and battery temperature is analyzed. Verification results under two driving cycles indicate that compared with the rule-based method, the proposed method improves fuel economy by 5.14% and 5.2% and decreases the temperature by 5.9% and 4.9%, respectively. The results demonstrate that the proposed PMP-MPC method can effectively improve fuel economy and reduce temperature. [ABSTRACT FROM AUTHOR]

For series hybrid electric vehicles, due to the limitation of engine operating characteristics, speed regulation is usually performed using discrete operating points. This leads to the problem of mixed integer programming when solving energy management problem. In this paper, an analytical method with strong real-time performance and small computational load is proposed. First, an intelligent cycle recognition system is designed. It can cluster driving cycles offline based on the probability distribution of the required power and efficiently recognize unknown driving cycles online. Then the analytical expression of power distribution is derived, and the selection scheme of engine operating point is given. Finally, the required power information obtained from the clustering is substituted into the analytical expression. The specific values of the corresponding analytical solutions for each type are computed offline. When facing unknown conditions, this method can match the power distribution scheme quickly once the driving cycle is recognized. The results of the simulation and hardware-in-loop experiments demonstrate that this method can effectively control the SOC trajectory and allocate power more optimally. Compared to the benchmark method, the proposed strategy improves the fuel economy by 5.52 % and 7.49 % in two cases, and the computational efficiency is significantly enhanced. • An intelligent driving cycle recognition system using deep clustering is designed. • An improved fully analytical ECMS is proposed. • Coordinative optimization for engine operation and power flow of SHEV. • The control performance is validated both in simulation and hardware-in-loop test. [ABSTRACT FROM AUTHOR]

The establishment of an efficient and economic means of producing hydrogen via electrocatalytic water-splitting will facilitate the extensive commercialization of fuel cells, and the round-the-clock model of electrocatalytic hydrogen production will alleviate the intermittency issue associated with sustainable energy sources. To enable this feature of renewable hydrogen energy, the key point is to develop cheap, large-scale and high-performance hydrogen evolution electrocatalysts as an alternative to noble metals. Here, a simple and robust physically sputtering strategy is reported to massively prepare a porous and defect-enriched W2C@WC1−x film electrocatalyst on carbon cloth (CC) in a W, C and Ar ion plasma atmosphere. The preferential re-sputtering mechanism promotes the loss of activated W and C ions in plasma and extracts more C from plasma, resulting in the ultimate formation of a defective W2C@WC1−x film. The ratio of W2C to WC1−x increased and the particle size decreased when additional nano-scale thickness Mo sublayers were further incorporated. A monolithic and porous W2C@WC1−x/Mo multilayer film as a binder-free electrocatalyst on flexible CC is created. It exhibits excellent HER performance with a low overpotential of 58 mV vs. RHE to drive a current density of −10 mA cm−2, a low Tafel slope of 41 mV dec−1 and over 6 days of long-term running stability in 0.5 M H2SO4 solution. It outperforms most of the recently reported outstanding non-noble metal electrocatalysts. This work sheds light on a new route to regulate the tungsten-carbide catalyst morphology and composition with an aim to boost its HER activity. [ABSTRACT FROM AUTHOR]

Series hybrid electric vehicles (S-HEVs) have attracted extensive attention thanks to the simple structure and excellent efficiency, which power transfer rely on high-voltage microgrids consisting of engine-generator set, battery, motor, and other actuators. However, with possible communication time delays (CTDs), the interaction between the actuators and control unit in terms of state and control command is desynchronize, resulting in the unstable operation of S-HEVs, such as engine stalls and bus voltage jitter. This presents a great challenge to the power coordinated control approach (PCCA) design that controls different actuators. Motivated by the mentioned above, this paper presents a time-delay-aware PCCA to achieve the stable driving of S-HEVs. First, an integrated powertrain control-oriented model that incorporates communication is built. Second, an increment model predictive control method (MPC) is designed. And then by leveraging the Lyapunov-Razumikhin stability theorem, a stability condition is derived by defining a parameterization weight matrix and known upper bound of CTDs, reducing the complexity of parameter designing. Additionally, an adaptive mechanism is designed to extend application of the proposed approach in unknown CTDs condition. Finally, the hardware-in-the-loop experiment is performed, and the results demonstrate that the presented approach in the mean and root mean square of the engine speed error and DC-bus voltage error decrease 39.87%, 43.85%, 44.67%, and 79.94% than nominal MPC in one period CTDs condition, respectively. And for the larger CTDs condition, the proposed method also shows efficient robustness. These substantiate that the proposed control method effectively improves vehicle running stability when encountering CTDs. • A control-oriented integrated model with communication time delays of the S-HEVs is established. • Design of a time-delay-aware power coordinated control approach utilizes MPC, and deduce a stability condition. • Development of an adaptive mechanism to address the control problem of the powertrain system with unknown CTDs. • A hard-in-the-loop experiment platform is constructed to validate the proposed power coordinated control approach. [ABSTRACT FROM AUTHOR]

The mechanical and tribological properties of three types of diamond like carbon (DLC) coatings, i.e., non-doped, Si-doped, and W-doped DLC, are evaluated. Dry reciprocating sliding wear tests were performed to evaluate the effect of sliding frequency/velocity on friction, adhesion, and wear. The degree of graphitization of non-doped and W-doped DLC increases with sliding velocity, which results in a lower coefficient of friction (COF), and a decrease in wear rate. Si-doped DLC, however, exhibits distinct friction behaviour, with increasing COF and severe fluctuations in friction at higher sliding velocities. In Si-DLC frictional heating drives the formation of an oxide-rich tribofilm and large amounts of Si-rich oxide wear debris that are both adhesive and abrasive. The oxide-rich tribofilm, and lack of surface graphitization, result in the severe fluctuations of Si-DLC friction via stick-slip and surface fracture/wear mechanisms, and significantly increased COF and wear rates at higher sliding velocities. • Mechanical and tribological properties of three diamond like carbon (DLC) coatings. • Si-doped DLC exhibits distinct friction with severe fluctuations at higher velocities. • Si-DLC was dominated by oxidative mechanisms, which degrade wear and friction. • A protective tribofilm containing higher graphitic carbon reduces friction of W-DLC. [ABSTRACT FROM AUTHOR]

Inspired by the imbalance between extrinsic and intrinsic tendon healing, this study fabricated a new biofilter scaffold with a hierarchical structure based on a melt electrowriting technique. The outer multilayered fibrous structure with connected porous characteristics provides a novel passageway for vascularization and isolates the penetration of scar fibers, which can be referred to as a biofilter process. In vitro experiments found that the porous architecture in the outer layer can effectively prevent cell infiltration, whereas the aligned fibers in the inner layer can promote cell recruitment and growth, as well as the expression of tendon-associated proteins in a simulated friction condition. It was shown in vivo that the biofilter process could promote tendon healing and reduce scar invasion. Herein, this novel strategy indicates great potential to design new biomaterials for balancing extrinsic and intrinsic healing and realizing scarless tendon healing.

Purpose: Surgery-induced immunosuppression is associated with infectious complications and cancer recurrence. This study aimed to characterize the effects of perioperative multiple doses of glucocorticoids on the peripheral immune environment in patients with non-small cell lung cancer., Methods: In this retrospective study, surgical patients with lung cancer were included. Lymphocyte subsets, lymphocyte phenotypes, lymphocyte functions, and inflammatory cytokines were evaluated in the peripheral blood preoperatively, then at 1 day and 7 days postoperatively. Levels of immune cells and inflammatory factors were compared between those who did or did not receive glucocorticoids at all time points., Results: Multiple doses or high doses (15-20 mg dexamethasone equivalents) of glucocorticoids that were all given within 24 h were associated with decreased absolute numbers of T cells, CD4 + and CD8 + T cells, B cells, and impaired T cells function at 1 day postoperatively while a single intraoperative low dose (5 mg) of dexamethasone had little influence on the peripheral environment. IL-1β, IL-6, and TNF-α were also more affected by multiple doses of glucocorticoids., Conclusions: Among patients with lung cancer, perioperative multiple doses of glucocorticoids that are all given within a short time are associated with decreased immune cell counts and impaired T cells functions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yang, Cai and Fu.)

Solid-liquid lubricating systems have received significant attention as a promising way for energy saving and emission control. For deeply understanding their tribological behaviors, it is necessary to study interaction mechanisms between solid and liquid lubricants from the tribochemical viewpoint, as tribofilms formed by tribochemical products on contact surfaces critically affect the whole tribological process. Continually or periodically monitoring tribofilm formation and evolution can contribute significantly to clarifying its dominating role in tribological behavior under boundary lubrication. However, detecting tribofilms in situ remains a big challenge for conventional surface analytical approaches, mainly due to their limitations in accessing tribofilms or low signal intensities of thin tribofilms. In this study, highly sensitive Raman-based profilometry with in situ potential has been developed for detecting molybdenum dialkyldithiocarbamate (MoDTC)-derived tribofilms and exploring their effect on a-C:H wear over time. The optical properties of tribochemical products formed on the coating surface in different wear stages could result in extra attenuation of Raman signal intensities in the form of measurement deviations in wear depth. By monitoring the deviations, key information of tribofilm compositions was obtained and a two-stage wear progression mechanism was proposed for the first time to clarify the detrimental effect of MoDTC-derived tribofilms on a-C:H wear by combining detailed structure and composition analyses.