The relaxation pseudocircuit method for analogue fault diagnosis

An efficient frequency domain relaxation frequency pseudocircuit (RPC) approach is proposed and the associated solvability conditions are derived for analogue fault diagnosis. In this approach all the elements in the circuit are described by the associated relaxation models and the solution of the RPC is obtained iteratively by the phaseor technique. Consequently the diagnostic process is unified in the frequency domain and both the development of the theory and the implementation for practical application are made easier via this unified approach. Besides, both the order of the RPC and the measurement cost are reduced. This is useful especially when a high-Q network is involved or the solution is hard to obtain in the time domain. Two examples are illustrated to show the efficacy of the proposed method.     

New Insight into the Effects of Metformin on Diabetic Retinopathy,Aging and Cancer: Nonapoptotic Cell Death,Immunosuppression, and Effects beyond the AMPK Pathway

Under metabolic stress conditions such as hypoxia and glucose deprivation, an increase in the AMP:ATP ratio activates the AMP-activated protein kinase (AMPK) pathway, resulting in the modulation of cellular metabolism. Metformin, which is widely prescribed for type 2 diabetes mellitus (T2DM) patients, regulates blood sugar by inhibiting hepatic gluconeogenesis and promoting insulin sensitivity to facilitate glucose uptake by cells. At the molecular level, the most well-known mechanism of metformin-mediated cytoprotection is AMPK pathway activation, which modulates metabolism and protects cells from degradation or pathogenic changes, such as those related to aging and diabetic retinopathy (DR). Recently, it has been revealed that metformin acts via AMPK- and non-AMPK-mediated pathways to exert effects beyond those related to diabetes treatment that might prevent aging and ameliorate DR. This review focuses on new insights into the anticancer effects of metformin and its potential modulation of several novel types of nonapoptotic cell death, including ferroptosis, pyroptosis, and necroptosis. In addition, the antimetastatic and immunosuppressive effects of metformin and its hypothesized mechanism are also discussed, highlighting promising cancer prevention strategies for the future.     

Analysis of operator-machine configuration for single and multi-processor machines

The research addresses the issue of determining optimal machine-operator configuration so that the ideal machine-operator ratio can be found and the operator efficiency can be calculated as a part of the overall input efficiency. Formula for optimal machine-operator ratio for single and multiple processor machines are derived. The formula allows us how to determine the best machine-operator ratio and calculate the operator usage efficiency. Simulations are used to verify the formula with matching product releasing times and machine utilisation rate. Data from a wafer reclaim factory is used to illustrate the calculation of equipment usage efficiency. Opportunity for doubling operator usage efficiency is identified using the derived formula. Contributions of this work include: (1) deriving a set of formula to calculate optimal operator-machine configuration and the operator usage efficiency for multi-processor machine sets; (2) identifying the inherent unusable time of operator due to the process time distribution of the machine tools; and (3) doubling the operator usage efficiency of the subject factory.     

A proposed process for systematic innovation

A systematic innovation process (SIP) derived from observations of business practices is proposed and exemplified. Time-wise, the SIP is a series of phases and stages which link the planned business processes from business opportunity identification to technology details to cross-industry application exploitation of newly developed technology/tools/products. Resource-wise, the SIP provides a platform to integrate heterogeneous resources and tools such as TRIZ (Theory of Inventive Problem Solving), non-TRIZ tools, and more opportunity identification and problem solving techniques for systematic innovation. Unlike brain-storming type innovation activities which are often ad-hoc and highly dependent on luck, systematic innovation regards the systematic development of innovative problem solving and/or opportunity identification. The proposed SIP is based on the authors’ observations of industry practices and has not been described elsewhere before. The framework integrates the full phases of systematic innovation processes providing a structured process to enable companies to systematically identify business opportunities and key problems, solve problems, and leverage developed tools/products/technologies for cross-industry exploitations. This SIP also allows for the integration of various tools and knowledge within the overall systematic and cyclic process to support systematic innovation.     

Effect of Aluminum Content on Microstructure and Mechanical Properties of Al x CoCrFeMo0.5Ni High-Entropy Alloys

High-entropy alloys Al _x CoCrFeMo_0.5Ni with varied Al contents (x = 0, 0.5, 1.0, 1.5, and 2.0) have been designed based on the Al _x CoCrCuFeNi system to improve mechanical properties for room and elevated temperatures. They have been investigated for microstructure and mechanical properties. As the aluminum content increases, the as-cast structure evolves from face-centered cubic dendrite + minor σ-phase interdendrite at x = 0 to B2 dendrite with body-centered cubic (bcc) precipitates + bcc interdendrite with B2 precipitates at x = 2.0. This confirms the strong bcc-forming tendency of Al. The room-temperature Vickers hardness starts from the lowest, HV 220, at x = 0, attains to the maximum, HV 720, at x = 1.0, and then decreases to HV 615 at x = 2.0. Compared with the base alloy system, the current alloy system has a superior combination of hardness and fracture toughness. In addition, Al _x CoCrFeMo_0.5Ni alloys except x = 0 display a higher hot hardness level than those of Ni-based superalloys, including In 718 and In 718 H, up to 1273 K and show great potential in high-temperature applications.     

Phase Diagrams of High-Entropy Alloy System Al-Co-Cr-Fe-Mo-Ni

The high-entropy alloy system Al-Co-Cr-Fe-Mo-Ni has been previously designed based on the Al _x CoCrCuFeNi system and was demonstrated to have great improvements in toughness at high hardness level and in softening resistance at elevated temperatures. For this promising system, it is important to have phase diagrams for further efficient alloy design and research. The current study combines the results from scanning electron microscopy, transmission electron microscopy, room-temperature and high-temperature x-ray diffractometry, and differential thermal analysis to construct approximate phase diagrams by varying the content of each composing element. Thermodynamic calculation in considering both mixing enthalpy and entropy was also used to justify the simple phase fields in these phase diagrams.     

A New Approach to Correlate the Frictional Performance of Fin-and-Tube Heat Exchangers in Wet Conditions

This study presents a new approach to correlate the frictional performance of fin-and-tube heat exchangers in "completely wet" and "partially wet" conditions by using "completely dry" data. A total of 22 samples of uncoated plain fin-and-tube heat exchangers are used to develop the associated frictional correlation. The developed correlation is capable of predicting the frictional performance of "completely wet" and "partially wet" conditions with a mean deviation of 7.2%.     

Effect of LiClO4 on the thermal and morphological properties of organic/inorganic polymer hybrids

This paper describes the thermal properties, morphologies, and interactions within the binary and ternary blends of poly(methyl methacrylate) (PMMA), octa(phenol)octasilsesquioxane (OP-POSS), and LiClO₄. In the binary PMMA/OP-POSS blends, the OP-POSS molecules tend to aggregate and result in a decrease (19 °C) in the glass transition temperature. In the ternary PMMA/LiClO₄/OP-POSS blends, however, the OP-POSS molecules form small sphere-like domains (20 nm) leading to the composite's glass transition temperature increasing by up to 30 °C. Based on these FT-IR spectra, the addition of LiClO₄ influenced the probability of hydrogen bonds formed between PMMA and OP-POSS and these SEM micrographs, DSC, and XRD data indicated that the addition of LiClO₄ is a convenient and simple approach toward dispersing the OP-POSS nanoparticles within PMMA, where the presence of LiClO₄ changes the physical effect of OP-POSS from that of a diluent role to a cross-linker role.     

Effects of microwave heating on dielectric and piezoelectric properties of PZT ceramic tapes

Commercial lead zirconate titanate (PZT) perovskite powders were used to fabricate ceramic tape and then sintered by microwave and conventional methods. Both dielectric and piezoelectric properties of PZT ceramic tapes were studied in terms of sintering process. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) show the PZT perovskite phase with smaller grain size and dense microstructure can be obtained at a lower sintering temperature by microwave process. It was also observed that shrinkage ratio and bulk density of the tapes sintered at 800 °C were obtained about 19% and 7.46 g/cm³ by the microwave heating method, respectively, that is corresponding to those values of sintered PZT tapes at 950 °C by conventional process. Moreover, the dielectric constant and maximum permittivity are increased about 30% as compared with conventional processing method. The experimental results demonstrated that the characteristics of the PZT tapes could be significantly improved by microwave heating method. These results demonstrate that such a simple approach can upswing the piezoelectric and dielectric properties of these tapes by using microwave process with a short heating time.