Search Results (503)

This study quantitatively evaluated the performance of a semi-active electronically controlled suspension (ECS) on low-friction (low-μ) road surfaces. A mid-size passenger vehicle equipped with a reverse-type continuously variable damper was tested through double lane change (DLC) maneuvers on the snow-covered Arjeplog test track in Sweden. The proposed semi-active control logic, based on Skyhook control, was designed to enhance handling stability by integrating roll rate control with yaw moment compensation control using roll moment distribution. Under semi-active only operation, the peak yaw-rate amplitude decreased by approximately 16% compared with the conventional fixed-damping mode, confirming a clear improvement in yaw stability. Furthermore, when the ECS operated in conjunction with the vehicle dynamic control (VDC) system through a lateral-acceleration signal linkage, the vehicle exhibited smoother roll and yaw responses, as well as highly repeatable steering behavior, across multiple tests. These results demonstrate that the proposed semi-active ECS not only improves transient yaw stability but also enhances response consistency when combined with VDC, providing a practical foundation for integrated chassis control development under real-world low-µ conditions, such as snow and wet roads. Full article

Improving the Prediction Performance (PP) of crack pipeline Failure Assessment Model (FAM) is of great significance for the safety of pipeline structure and engineering. However, conventional optimizations for PP always focus on either safety or accuracy, failing to balance the overall requirements of structural applications. Therefore, this paper proposes an optimization procedure for comprehensively improving FAM’s PP. The establishment of the procedure can be divided into three parts: 1. setting a rational and robust optimization target, where the Improved Guo-Ni Model (IGNM) is raised to provide an absolute score s for fully quantifying FAM’s PP in terms of the multi-dimensional performances, including stability and Distributional Location Characterizations (DLCs) of FAM’s prediction results; 2. determining the candidate solutions which are selected as the Critical Safety Factor (CSF) values related to FAM’s prediction confidence level (R₁) in this paper; 3. constructing the optimization framework based on the Particle Swarm Optimization algorithm to search for the optimal CSF (OCSF) that can maximize s. Finally, empirical verification results show that the procedure enhances the overall s values of BS 7910:2019 and CorLAS models by 3.32% and 6.09%, respectively, through balancing DLCs, which increases the applicability of FAM across different projects and provides a new approach for the optimization control of FAM’s overall performance. Full article

The chemical mechanical polishing (CMP) process in semiconductor fabrication faces challenges such as slurry agglomeration, scratches, and contamination, which degrade process reliability and device quality. To mitigate these challenges, this study investigated the application of hydrophobic surface coatings on CMP components. Polytetrafluorothylene (PTFE) was deposited onto stainless steel substrates, while diamond-like carbon (DLC) films were coated on PEEK-based retainer rings, with material selection guided by their surface energy characteristics and mechanical robustness. The hydrophobic performance of the coatings was systematically evaluated through contact angle measurements and surface roughness analysis (Ra, Rpk, Sa, Spk). Under oxide CMP conditions, 60 h reliability tests using non-patterned wafers demonstrated that PTFE-coated stainless-steel surfaces significantly reduced slurry-induced particle accumulation and suppressed scratches compared with uncoated substrates. In addition, PTFE provided stable hydrophobicity and effective scratch resistance, while DLC exhibited superhydrophobic behavior with contact angles exceeding 160°, offering potential for even greater protection against surface damage. The wettability of DLC coatings was further tunable via sp³/sp² carbon bonding ratios and surface roughness, consistent with the predictions of the Cassie–Baxter and Wenzel models. These findings establish a framework for surface modification of CMP hardware. The integration of PTFE and DLC coatings effectively enhances hydrophobicity, suppresses slurry contamination, and improves scratch reliability, thereby offering a practical route for designing hydrophobic CMP components that strengthen process stability and extend equipment lifetime in advanced semiconductor manufacturing. Full article

Background/Objectives: Patients with liver cirrhosis (LC) present hematological abnormalities with multiple etiologies. As liver function deteriorates, these abnormalities become more evident, conferring a higher risk of morbidity and mortality. The objective of this study was to determine the hematological alterations present in patients with compensated vs. decompensated liver cirrhosis. Methods: This study is a prospective study conducted in a tertiary hospital with patients diagnosed with compensated liver cirrhosis monitored by the Gastroenterology Department, in addition to patients hospitalized for decompensated liver cirrhosis. Serum samples were taken after an informed consent form was signed, and clinical and biochemical data were recorded. Results: Seventy-three percent of patients with decompensated liver cirrhosis (DLC) suffered from anemia and thrombocytopenia at the start of the study. Patients with LC are at greater risk of developing leukopenia/lymphopenia if they are in a more advanced stage of the disease, and the erythrocyte sedimentation rate (ESR) and C-reactive protein levels are higher in this group than in patients with compensated LC. Twenty-eight percent (4/14) of patients with DLC were admitted due to evidence of acute gastrointestinal bleeding; the remaining 18 patients suffering from CLC and DLC were recorded as having an average hemoglobin level of 11 g/dL with no evidence of bleeding. Conclusions: Hematological abnormalities are common in patients with LC, particularly in the advanced stages of the disease, and these abnormalities increase the risk of morbidity and mortality. The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised in accordance. Full article

This study presents a highly effective method for depositing diamond-like carbon (DLC) films onto pipe substrates using a scanning deposition by plasma enhanced chemical vapor deposition. A microwave–sheath voltage combination plasma was employed to generate local high-density plasma along a rotating pipe. While conventional contact-mode deposition using a metal contactor suffers from arcing and surface damage due to unstable sliding contact during rotation, a non-contact deposition using a metal antenna was developed to overcome these limitations. Electromagnetic field simulations were conducted to evaluate microwave power absorption in various antenna geometries, showing that the flat-plate antenna demonstrated the most effective power coupling. Subsequent scanning deposition experiments to a rotating pipe using flat-plate antennas of different lengths revealed that the 100 mm configuration achieved the highest deposition volume rate (exceeding that of the contact-mode) while avoiding arcing. Optical emission observations during deposition confirmed the formation of high-density plasma surrounding the flat-plate antenna and Raman spectroscopy of the deposited film showed typical spectra of DLC films. The deposition rates of DLC-coated pipe showed no significant variation with respect to rotational angle, suggesting that rotation during deposition contributes to achieving uniform film thickness along the circumferential direction of the pipe. Full article

We propose an integrated model predictive control (MPC) scheme for steering-robot path tracking that directly optimizes the robot voltage and embeds steering-angle limits as linear-inequality voltage constraints inside the optimizer. This avoids cascade-induced error accumulation and extra phase lag in MPC+PID while guaranteeing actuator-level feasibility. A Simulink–CarSim co-simulation evaluates two scenarios: (1) double-lane change (DLC) at 70/40 km·h⁻¹; and (2) straight-line tracking with/without sinusoidal crosswind modeled as an equivalent lateral force. Metrics include lateral-error RMS/Peak/P95 and real-time statistics (WCET, average per-update time, and utilization rate). The results show consistent gains: at 70 km·h⁻¹, RMS/Peak/P95 decrease by 22.3%/18.0%/17.7%; and, at 40 km·h⁻¹, by 17.0%/19.5%/18.9%. Real-time feasibility is met with $T$ = 10 ms, average ≈ 1.7 ms, WCET ≈ 2.1~2.3 ms, utilization ratio ≈ 0.17. Under crosswind, robustness improves over the cascaded baseline by 9.7%/35.6%/30.8% on RMS/Peak/P95. The method provides tighter tracking, stronger disturbance rejection, and strict timing for safety-critical testing. Full article

The inherent brittleness and poor fracture toughness of diamond-like carbon (DLC) films significantly limit their long-term reliability in mechanical and tribological applications. Among various strategies to enhance toughness, doping with non-carbide-forming metals (e.g., Ag, Cu) has emerged as a highly effective approach due to their ductile properties and compatibility with carbon matrices. This review comprehensively examines the underlying toughening mechanisms induced by non-carbide metal doping in DLC films. We systematically analyze how metal incorporation influences film microstructure, stress state, and crack behavior throughout the entire lifecycle—from deposition to mechanical testing. Five primary toughening mechanisms are identified and discussed: (I) bombardment-induced compressive stress relaxation during film growth; (II) refinement of carbon atomic clusters and enhancement of grain boundary sliding; (III) inhibition of dislocation accumulation through moderated carbon atom repulsion; (IV) plastic deformation, crack bridging, and strain field relaxation at crack tips; (V) shear-induced stress relief via soft metal particles. Among these, Mechanism IV (ductile phase toughening) is identified as the dominant contributor, and their synergistic action can lead to orders of magnitude improvement in wear resistance and a significant increase in crack propagation resistance. Furthermore, the critical role of doping content is emphasized, revealing an optimal concentration range (e.g., ~10–15 at.% for Ag and Cu) beyond which toughness may deteriorate due to excessive boundary formation or hardness loss. This work provides a mechanistic framework for designing toughened DLC films and guides future efforts in developing high-performance, durable carbon-based coatings. Full article

By alternately depositing hydrogen-free amorphous carbon (a-C) and hydrogenated amorphous carbon (a-C:H) nanolayers on HSLA-100 steel through arc-ion plating, multilayer diamond-like carbon (DLC) architectures were engineered, with the modulation period adjusted from 1 to 10 cycles. SEM and Raman spectroscopy served as the analytical tools for characterizing the microstructure. For assessing key functional behaviors, nanoindentation was used to test mechanical properties, dry-sliding tribometry and in-situ tribocorrosion tests targeted tribological and tribocorrosion performance, and polarization tests focused on corrosion resistance. Introducing C₂H₂ increased the sp³ fraction and hardness relative to pure a-C. The ten-period film (S5) yielded the highest H/E (0.0767) and H³/E² (0.171), reflecting the best hardness–toughness synergy. All coatings lowered the dry friction coefficient to 0.08–0.10 and cut wear by more than 1 order of magnitude versus the substrate; the ten-period film (S5) showed the minimum dry wear rate (1.39 × 10⁻⁷ mm³·N⁻¹·m⁻¹) and tribocorrosion wear rate (4.53 × 10⁻⁷ mm³·N⁻¹·m⁻¹) in 3.5 wt% NaCl. The superior performance is due to interlayer interfaces that dissipate stresses, arrest crack propagation, and block electrolyte ingress through defects. These findings indicate that the rational stacking of a-C/a-C:H significantly improves the tribological and tribocorrosion resistance of HSLA-100, providing a reliable protective approach for components used in marine services. Full article

Diamond-like carbon (DLC) films exhibit superior tribological properties; however, their widespread adoption in precision manufacturing is hampered by inherent brittleness and a lack of reliable toughness characterization methods at the micrometer scale. This review critically examines existing techniques for evaluating DLC film toughness, highlighting limitations due to film thickness constraints and subjective failure definitions. We focus on two prominent micro-scale methods: impact testing and scratch testing. Impact toughness is assessed through energy absorption analysis based on impact crater morphology, including crack patterns and delamination areas. Scratch toughness is evaluated using critical loads (Lc₁, Lc₂) and the derived Crack Propagation Resistance (CPRS) parameter, complemented by microscopic failure analysis. We argue that neither method alone suffices for comprehensive toughness assessment. Instead, we propose a synergistic strategy integrating both techniques to provide a practical and comprehensive evaluation encompassing energy- and stress-based failure mechanisms under varying loading conditions. This approach offers a practical framework for developing tougher DLC coatings. Full article

With the increasing demand for energy conservation and emission reduction in the automotive industry, optimizing the performance of cylinder liner and piston ring pairs in engines has become crucial. Aluminum–silicon alloy cylinder liners, known for their lightweight and excellent thermal conductivity, have emerged as a new trend in cylinder liner materials. Given the relatively moderate hardness of Al-Si alloys, judicious selection of piston rings is imperative to ensure optimal performance. This study investigates the tribological properties of aluminum–silicon alloy cylinder liners paired with CKS and DLC piston rings. The surface morphology and hardness of the test materials were characterized, and reciprocating friction and wear tests were conducted, using a tribometer to simulate operating conditions. The friction coefficient and wear volume were used as indicators to evaluate the tribological properties of the piston rings. The results show that, when the aluminum–silicon alloy cylinder liner was paired with a DLC piston ring, the friction coefficient was 27.82% lower, and the wear volume of the cylinder liner was 83.52% lower, compared to pairing with a CKS piston ring. When paired with a CKS piston ring, wear was exacerbated because silicon particles were easily dislodged to form abrasive particles. This particle detachment is mainly caused by the collision between the fine ceramic particles embedded in the CKS coating and the silicon particles (≤5 μm) uniformly distributed in the Al-Si alloy cylinder liner during the sliding process. The DLC piston ring, containing both sp² and sp³ hybridized carbon–carbon bonds, combined excellent lubrication properties with high hardness, resulting in minimal wear on both the cylinder liner and piston ring. Specifically, the DLC coating has a hardness of 2300 HV_0.3, which is 2.42 times that of the CKS piston ring (950 HV_0.3); the sp³-hybridized carbon in the DLC coating enhances its wear resistance to resist scratching from silicon particles in the cylinder liner, while the sp²-hybridized carbon forms a graphite-like transfer layer at the friction interface to reduce frictional resistance. In conclusion, the aluminum–silicon alloy cylinder liner paired with a DLC piston ring exhibits superior tribological properties. Selecting an appropriate piston ring can significantly enhance the tribological properties of the cylinder liner–piston ring pair, thereby extending the engine’s service life. Full article

Offshore wind turbines are rapidly scaling in size, which amplifies the need for credible integrated load analyses that consistently resolve the coupled dynamics among rotor–nacelle–tower systems and their support substructures. This study presents a comprehensive ultimate limit state (ULS) load assessment for a fixed jack-up-type substructure (hereafter referred to as K-wind) coupled with the IEA 15 MW reference wind turbine. Unlike conventional monopile or jacket configurations, the K-wind concept adopts a self-installable triangular jack-up foundation with spudcan anchorage, enabling efficient transport, rapid deployment, and structural reusability. Yet such a configuration has never been systematically analyzed through full aero-hydro-servo-elastic coupling before. Hence, this work represents the first integrated load analysis ever reported for a jack-up-type offshore wind substructure, addressing both its unique load-transfer behavior and its viability for multi-MW-class turbines. To ensure numerical robustness and cross-code reproducibility, steady-state verifications were performed under constant-wind benchmarks, followed by time-domain simulations of standard prescribed Design Load Case (DLC), encompassing power-producing extreme turbulence, coherent gusts with directional change, and parked/idling directional sweeps. The analyses were independently executed using two industry-validated solvers (Deeplines Wind v5.8.5 and OrcaFlex v11.5e), allowing direct solver-to-solver comparison and establishing confidence in the obtained dynamic responses. Loads were extracted at the transition-piece reference point in a global coordinate frame, and six key components (Fx, Fy, Fz, Mx, My, and Mz) were processed into seed-averaged signed envelopes for systematic ULS evaluation. Beyond its methodological completeness, the present study introduces a validated framework for analyzing next-generation jack-up-type foundations for offshore wind turbines, establishing a new reference point for integrated load assessments that can accelerate the industrial adoption of modular and re-deployable support structures such as K-wind. Full article

Floating offshore wind turbines (FOWTs) face significant challenges in maintaining reliable power generation while mitigating structural loads, which are critical for reducing maintenance costs and extending service life. To address these issues, this study evaluates the effectiveness of a Soft Power Limitation Control (SPLC) strategy through numerical simulations in DNV Bladed. Two representative design load cases were considered, with design load case (DLC) 1.1 representing normal turbulence and DLC 2.3 representing an extreme operating gust. Under DLC 1.1, SPLC substantially reduced tower fatigue loads, lowering the damage equivalent loads (DELs) of side-to-side and fore–aft bending moments by 21 percent and 15.2 percent, respectively, while blade and mooring loads remained nearly unchanged. Platform motions exhibited modest improvements, including a 6.5 percent reduction in surge peak-to-peak, 2.2 percent in surge RMS, and 2.6 percent in pitch peak-to-peak. Under DLC 2.3, SPLC effectively alleviated extreme responses, decreasing the maximum tower side-to-side bending moment by 30.7 percent and the blade flap-wise bending moment by 15.6 percent, without adverse effects on six-degrees-of-freedom (6-DOFs) platform motions. Overall, the results confirm that SPLC enhances both fatigue and extreme load performance while maintaining stability, highlighting its potential as a practical and cost-effective control strategy to improve the reliability, durability, and commercial viability of FOWTs. Full article

This study examines a duplex surface treatment combining case-hardening and Physical Vapor Deposition (PVD) techniques, widely used to enhance mechanical strength and surface durability of components under high wear conditions. Despite industrial relevance, understanding of the interaction between case-hardened substrates and Diamond-Like Carbon (DLC) coatings remains limited. Using the Daimler-Benz Rockwell-C adhesion test, this research evaluates duplex-treated system performance, focusing on adhesion characteristics and mutual behavior between the support layer and DLC topcoat. The experimental approach assesses coating adhesion and substrate influence on coating integrity. Through systematic analysis, the study aims to optimize surface engineering practices for enhanced reliability and wear resistance. Full article

Τhe self-assembly behavior of a series of amphiphilic diblock copolymers, each consisting of a hydrophilic poly(N-vinyl pyrrolidone) (PNVP) block and a hydrophobic block derived from n-alkyl vinyl esters, namely poly(vinyl butyrate) (PVBu), poly(vinyl decanoate) (PVDc), and poly(vinyl stearate) (PVSt), in aqueous solutions was investigated. Dynamic and static light scattering (DLS and SLS) techniques were employed to monitor the micellization behavior. In addition, the self-assembled structures were observed with Transmission Electron Microscopy (TEM). The effect of the nature of the hydrophobic block, the copolymer composition and the copolymer molecular weight on the self-assembly properties was thoroughly examined. The encapsulation of curcumin and indomethacin within the dry cores of the micellar structures was conducted in aqueous solutions for all block copolymers at various curcumin/indomethacin-to-polymer mass ratios. UV-Vis spectroscopy was used to evaluate the drug-loading capacity and efficiency (%DLC and %DLE). In several cases, the encapsulation of both hydrophobic drugs was found to be nearly quantitative. Combined with the observed stability of the micellar structures, these findings suggest that the block copolymers demonstrate significant potential as carriers for drug delivery applications. Full article

The primary objective of this research is to simplify and make the industrial manufacturing process of coated maraging steels more economical by combining the advantages of additive manufacturing with simultaneous bulk (aging) and surface (nitriding) treatment in an effective manner. With this aim, preliminary experiments were performed that demonstrated the hardness (and related microstructure) of an as-built MS1 maraging steel, produced by selective laser melting (SLM), is comparable to that of the bulk maraging steel products treated by conventional solution annealing. The direct aging of the solution-annealed and as-built 3D printed maraging steel resulted in similar hardness, indicating that the kinetics of the precipitation hardening process are identical for the steel in both conditions. This assumption was strengthened by a thermodynamic analysis of the kinetics and determination of the activation energy for precipitation hardening using Differential Scanning Calorimetry (DSC) measurements. Industrial target experiments were performed on duplex-coated SLM-printed MS1 steel specimens, which were simultaneously aged and salt-bath nitrided, followed by PVD coating with three different ceramic layers: DLC, CrN, and TiN. For reference, similar duplex-coated samples were used, featuring a bulk Böhler W720 maraging steel substrate that was solution annealed, precipitation hardened, and salt-bath nitrided in separate steps, following conventional procedures. The technological parameters (temperature and time) of the simultaneous nitriding and aging process were optimized by modeling the phase transformations of the entire heat treatment procedure using DSC measurements. A comparison was made based on the in-depth hardness profile estimated by the so-called expanding cavity model (ECM), demonstrating that the hardness of the surface layer of the coated composite material systems is determined solely by the type of the coatings and does not influenced by the type of the applied substrate materials (bulk or 3D printed) or its heat treatment (whether it is a conventional, multi-step treatment or a simultaneous nitriding + aging process). Based on the research work, a proposal is suggested for modernizing and improving the cost-effectiveness of producing aged, duplex-treated, wear-resistant ceramic-coated maraging steel. Full article