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The Correlation Between Wear and Lubricating Film Thickness in the Tribocorrosion of CoCrMo Alloy
Full text linkTribocorrosion modelling of passive metals considering the lubrication effect from solution is still not well studied. A lubricated tribocorrosion model for CoCrMo alloy metal-on-metal hip joints has been developed, while the generalization of this model is restricted by Dowson’s empirical correlation. This study explored the correlation between wear of CoCrMo alloy in tribocorrosion and lubricating film thickness. The results showed that the chemical, mechanical and total wear volumes of CoCrMo alloy in tribocorrosion were significantly influenced by the lubrication effect from the solution. Good correlations were obtained between the lubricating film thickness and chemical, mechanical and total wear, respectively. The new chemical and mechanical wear correlations could be used to generalize the current lubricated tribocorrosion model for CoCrMo alloy
Application of The “Smart Manufacturing” System to Detect a Fire in an Industrial Premises
Full text linkThe article considers the issue of identifying patterns between the readings of various sensors to reduce the number of false alarms of the fire safety system in an industrial premises. The identified rules will be used in the “Smart Manufacturing” system being developed
In-Situ Inspection for Robotic Polishing of Complex Optics
Full text linkAbstract: With rapid development of modern optical manufacturing technologies, industrial robot polishing has a wide range of application scenarios and broad development potential in the field of optical manufacturing. The integration of in-situ inspection is a key to improving the reliability and efficiency of precision manufacturing. Deflectometry is a promising in-situ measuring method due to its large dynamic range and structural flexibility. The measurement principles, calibration methods, phase retrieval, surface reconstruction, scope extension etc are presented systematically. The key problems of height-slope ambiguity and position-angle uncertainty are analyzed in details. High-precision measurement of complex optical elements is realized, which is of great significance to the intelligent manufacturing of key optical components
Retrospect on the Preparation and Application of Perovskite Materials
Full text linkIn recent years, the diversity of new organic-inorganic hybrid perovskite materials has received extensive attention, for tremendous outstanding properties including large optical absorption coefficients, high carrier transport mobilities, long-range charge-carrier diffusions, low exciton binding energies, adjustable bandgaps, narrow-band bright photoluminescence as well as the compatibility of simple processing techniques. Because of these excellent properties, perovskite materials are widely used in solar cells, light-emitting devices, photodetectors, photocatalysis, etc. Here we reviewed the fundamental structure and properties of perovskite materials, and summarize the diverse preparation methods of perovskites along with the key factors in nucleation and growth control to prepare high-quality bulk crystals or films with less defects and stabilized performances against the external corrosive environments. The applications of perovskite materials accompanied with the relative bulk or interface ameliorations are discussed, and finally the prospects of such materials are expected. Overall, this review demonstrates the prevailing preparation mechanisms, challenges for high-quality perovskite materials and their vital importance in corresponding applications
Mechanical Characterization of Natural and Synthetic Fibres using Sandwich Structures Under Bending
Full text linkFibre-reinforced sandwich panels are a well stablished design solution for applications that require high stiffness and low weight, but the high cost and enviromental impact of synthetic fibres have prompted the research for sustainable alternatives, such as natural fibres. While they offer potential for cost reduction and environmental sustaintalibity, their mechanical properties may compromise structural reliability. In this context, this work compares the equivalent stiffness of different composite sandwich panels under bending, using carbon, glass, linen, jute and cotton fibres as reinforcement. The specimens were produced using the Vacuum Assisted Resin Transfer Moulding (VARTM) and tested under four point bending conditions. Analytical methods were used for mechanical characterization, followed by Finite Element Method (FEM) validation. The results show that carbon fibre yields a greater stiffness-to-weight ratios followed by glass, jute, linen and cotton fibres. Sandwich panels with natural fibres reinforcement showed relative bending performances ranging from 19% to 35% of the carbon fibre ones
A Statistical Methodology of Cyclic Plasticity Inhomogeneity at Grain Scale
Full text linkThe inhomogeneous plastic deformation has important effects on the manufacturing process and the fatigue property of mechanical products. To directly and correctly evaluate the deformation inhomogeneity of grain scale under cyclic loading, a statistical method is proposed and named as the normalized standard deviation. The method is comprised of the following steps: (1) Construct a representative volume element (RVE) of polycrystalline by Voronoi tessellation and electron backscatter diffraction, and calculate the grain strain by a constitutive model of crystal cyclical plasticity. (2) Deal with grain strain data of RVE by Min-max normalization method. (3) Compute the standard deviation of the normalized data as the identification of mesoscopic inhomogeneity. In order to validate the proposed normalized standard deviation, the contrastive analyses with the strain contours, the weighted standard deviation and the coefficient of variation are conducted at the same conditions of cyclic loading. The results demonstrated that the normalized standard deviation was the best as the indication of cyclic plasticity inhomogeneity among the above methods
Single-Layer 79 GHz Microstrip Patch Array for All-Weather Automotive Radar
Full text linkAdvanced driver-assistance systems (ADAS) demand radar sensors that combine centimetre-level resolution, wide angular coverage, and all-weather reliability, yet must fit behind a plastic bumper at automotive cost. This study meets that challenge with a fully self-contained 79 GHz front-end fabricated on a single-layer RO3003 printed-circuit board.
Closed-form cavity models, applied from first principles, yield patch dimensions without iterative tuning. Sixteen patches arranged in a 4 × 4 half-wavelength array deliver 16 dBi broadside gain, 3.2 GHz (−10 dB) impedance bandwidth, and a 33° half-power beam-width, thereby covering the entire 76–81 GHz allocation.
Solving the radar-range equation shows that even under 8 dB km⁻¹ heavy-rain attenuation the sedan detection limit contracts by only 2 m (51 m → 49 m), while motorcycle and pedestrian ranges are virtually unaffected. To our knowledge, this is the first single-layer PCB radar front-end to achieve such performance without empirical tuning, and it offers a clear upgrade path toward imaging radar and highway ACC
Stability Enhancement in High-Penetration Wind Power Grid Integration During Fault Conditions Using a Combined MBPSS and FACTS Device Approach
Full text linkThis study investigates how a combination of Multi-Band Power System Stabilizers (MBPSS) and Flexible AC Transmission System (FACTS) devices might improve stability in power networks with significant wind energy penetration under fault conditions. Maintaining system stability becomes increasingly important as wind power integration rises, especially when there are disruptions that could cause electromechanical oscillations. The study uses MBPSS to model a wind turbine powered by a Doubly-Fed Induction Generator (DFIG) and assesses the performance of several FACTS devices, including Unified Power Flow Controllers (UPFC), Static Synchronous Series Compensators (SSSC), and Static Synchronous Compensators (STATCOM). According to simulation results, combining these technologies reduces oscillations significantly—for example, damping times decreased from 8 s (without controllers) to 3 s (with MBPSS and UPFC), and frequency deviations were maintained within ±0.5 Hz. These results demonstrate that the UPFC and MBPSS combination is the most effective in stabilizing the grid when wind energy levels are high
Formation Mechanism of Eutectic Microstructure for CaHfO3/HfO2
Full text linkThe mechanism of fine eutectic structure formation for CaHfO3/HfO2 was investigated. CaHfO3/HfO2 eutectic solidification film was prepared using a high-power laser with 1400W. The film preparation was conducted in a furnace at 1300oC. The scanning speed of laser was set to 500 to 2000 mm/s. The scanning speed of the laser was greatly varied to create a solidified film and the intermediate steps of micro-structure formation were observed. The micro-structure morphology immediately after solidification was a structure in which an intermediate phase was surrounded by an HfO2 phase. CaHfO3 phase deposited in dot-like form from the intermediate phase. It was confirmed that the dot-like deposit phase connected through atomic diffusion at high temperatures, ultimately forming a fine lamellar structure. It was confirmed that the fine eutectic microstructure of CaHfO₃/HfO₂ is not formed by competitive growth at the melting point during conventional eutectic solidification, but rather is ultimately formed through repeated phase separation after the solidification
The Dynamic Model, Based on the Quantity Theory of Money Plus the Velocity of Money Circulation: Factor Analysis of the Inflation in USA During 1960-2024
Full text linkThe model for factor analysis of inflation is presented and applied to the inflation in USA during 1960-2024. GDP deflator is decomposed into three growth rates: M2, velocity M2V and real GDP. The subject is impact of money supply and velocity to the CPI and GDP deflator. As a result – the dynamic model is proposed for the factor analysis. Some results of regressions are exposed to check relations between CPI, GDP deflator and those factors. The scientific novelty – the velocity of money circulation may play key role in inflation. Velocity depends on two basis trade-offs: expected risk and return on deposits and expected risk and return in financial markets. Velocity is generally stable and tends to decrease when inflation factors are anchored.
When a central bank control prime rate and ignore money supply, the market price for capital is distorted. Then three factors may come into play: an increase in inflation expectations due to increase of money supply; an increase of the money velocity due to inflation expectations; a decrease of real GDP growth due to a high prime rate. All three factors accelerate inflation and all are ignored by New Keynesian models, currently employed by central banks. Therefore, it is proposed to improve management of inflation by replacing the New Philip’s curve with the factor model based on money supply, money velocity and real GDP growth