Search Results (153)

This study proposes a condition-based maintenance monitoring method based on Geometry-based Optical Focus Metrology (GOFM) to detect wafer table edge deterioration early and enable proactive interventions before actual Critical Dimension (CD) bridge defects occur. In advanced Deep Ultraviolet (DUV) immersion photolithography, prolonged equipment operation mechanically wears the wafer table, inducing Edge-Roll-Off (ERO). Because conventional optical metrology struggles to separate this localized defocus from process noise, this work utilizes the existing GOFM technique to isolate the pure focus residual within the 140–147 mm radius region. To quantify this hardware-specific degradation, a mathematical dual-indicator system was constructed. This framework integrates a statistical threshold, the Range Percentile 97%, to reject baseline measurement noise, and a geometric variable, Slope × 3, to capture the topographical drop in the outermost 3 mm. Analysis of long-term time-series data from multiple High-Volume Manufacturing (HVM) scanners confirmed a strong correlation ($R^2=0.93$) between these indicators. Furthermore, we proved that the drift trajectory of Slope × 3 deterministically predicts mechanical failure prior to defect occurrence on production wafers. Based on these findings, an automated condition-based maintenance architecture was designed using an OR-logic decision gate. By triggering a preemptive table replacement at a quality-based critical warning threshold, this system converts routine time-based scheduling into a data-driven paradigm, maximizing both edge yield and equipment uptime. Furthermore, this proposed framework establishes a solid foundation for future extensions toward machine learning-based predictive maintenance. Full article

This study presents an experimental investigation of 3D-printed poly(lactic acid) samples (PLA) subjected to high-voltage AC stress. Although additive manufacturing is gaining importance in electrical engineering, studies on FDM-printed materials have concentrated mainly on mechanical behaviour. Their dielectric strength under oil-immersed high-voltage stress—a critical aspect for insulation applications—has not been systematically investigated. Additive manufacturing is increasingly considered for auxiliary insulating components in oil-immersed high-voltage equipment; however, process-induced voids and interlayer interfaces can intensify the local electric field and reduce dielectric strength. This work evaluates the AC breakdown strength of 3D-printed PLA specimens under oil immersion using the standard AC electrical strength test method for solid insulating materials. Two parameter sets were investigated: extrusion temperature (190–240 °C ) at a constant nozzle diameter, and nozzle diameter ($0.3$–$0.6 \mathrm{mm}$) at a constant extrusion temperature of $T_{\mathrm{e}}=200°\mathrm{C}$. Breakdown data were analysed using the standard two-parameter Weibull approach typically used in the statistical evaluation of electrical insulation breakdown strength, with the results additionally expressed in terms of the $B_{10}$, $B_{50}$, and $B_{90}$ percentiles. The experimental observations were interpreted using simplified electric-field simulations representing inter-bead and interlayer voids. The results indicate that, for a given material, there exists an optimal extrusion temperature that yields the highest electrical breakdown performance. Full article

Several hydrogen explosions have been reported in ash treatment facilities at municipal solid waste incineration plants, highlighting the need for effective suppression measures. This study focuses on controlling temperature changes during the conveyor transportation process as a method to reduce hydrogen generation from incineration ash. Experiments were conducted in which heated simulated incineration ash was immersed in water inside a vessel and allowed to cool naturally. The results show that higher water temperatures during immersion significantly decreased the amount of hydrogen gas generated. Specifically, it was found that hydrogen generation ceased when the simulated incineration ash was immersed in water at 90 °C and subsequently allowed to cool naturally. These findings suggest that temperature control may contribute to preventing hydrogen explosion hazards in ash handling systems. Full article

This study investigates the long-term resistance of an environmentally friendly composite made from a blend of local Ordinary Portland Cement (OPC) and ground granite waste powder (G). The composite was subjected to complete static immersion for up to twenty-four weeks in three types of water: potable water, groundwater, and seawater. The experimental work evaluated the effects of exposure to these three water types on various characteristics of the granite–cement composite (GCC), including compressive strength, mass gain, portlandite [CH] content, bulk density (D), total porosity (p), compactness, water absorption (A), and pH of the immersing media. Additionally, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal analysis (TGA and DTA) were used to investigate how exposure to the three water environments altered the internal microstructure of the hydration phases of the composite over the twenty-four-week period. This systematic approach provides valuable insights into the variations that may occur in solid hydration outcomes and their sustainability in flooding scenarios. The data obtained from these analyses revealed that the granite–cement composite exhibits acceptable thermal resistance and endurance to deterioration in aquatic environments. The cement formulation contains 20% by mass of ground granite waste powder, with a water-to-cement ratio of 35%. After 24 weeks of complete static immersion, the composite achieved compressive strength values close to 24 MPa. Solidifying radioactive waste in cement–granite is a newly developed method that improves sustainability by formulating a more stable, durable, cost-effective, and less hazardous waste form. Therefore, the granite–ordinary cement composite being studied is recommended as an inert matrix for solidifying and stabilizing certain categories of radioactive waste. Full article

In response to the key issues of complex internal structure, significant attenuation of partial discharge (PD) ultrasound signal propagation, and low sensor sensitivity in large oil–immersed power transformers, this paper analyzes the multi–order resonant mode vibration characteristics of the shaft–type fiber optic ultrasound sensor core structure. The displacement distribution patterns of the core structure in both transverse and longitudinal resonant modes are clarified. A strategy using oblique fiber winding rings is proposed to eliminate the problems of strain cancellation and non–accumulation of displacement in transverse and longitudinal resonant modes, which are common in traditional fiber optic ultrasound sensors with parallel fiber windings. Furthermore, design principles are provided to enhance the coverage of the free end and the high–strain regions with semi–high symmetry, as well as the vector–integrated response suitable for multi–order modes. Experimental results show that, in typical PD model detection, the oblique winding sensor exhibits a more prominent response near the high–order resonances of the core, with a detection sensitivity approximately 2.5 times higher than that of the parallel winding structure, and an overall sensitivity at least 7.4 times greater than that of traditional Piezoelectric (PZT) sensors. This demonstrates that the fiber winding method is a key design parameter determining the acoustic–solid coupling efficiency and high sensitivity performance of shaft–type fiber optic interferometric PD sensors, providing a feasible path for high–reliability fiber optic sensing solutions for online monitoring of transformer partial discharges. Full article

The present study investigates the thermal conductivity (λ) and convective heat transfer coefficient (h) of AA 6082 aluminum cellular structures immersed in water and air using a thermal conductivity probe (TCP) manufactured by the authors. The probe is a cylindrical needle 0.6 mm in diameter (D) and 60 mm in length (L), obtaining an L/D ratio = 100 ratio, which satisfies the infinite line-source assumption and enables discrimination between pure-fluid and composite (fluid + solid) thermal behavior. Cellular samples are manufactured with the Lost-PLA process and tested at temperatures of 5, 20, and 40 °C, feeding the TCP with different currents, under controlled heating conditions. The results show that the presence of the aluminum cellular structure enhances heat transfer compared with that of pure fluids. In air, the effective thermal conductivity is higher by approximately 37–45% than that in pure air, reaching about 0.038 W m⁻¹ K⁻¹ at higher temperatures. In water, λ increases from approximately 0.8 to 1.2 W m⁻¹ K⁻¹ over the investigated temperature range, corresponding to an enhancement of about 45–80% compared with that of pure water. Similarly, the convective heat transfer coefficient is higher by about 22–32% in air (h ≈ 38–41 W m⁻² K⁻¹) and 19–54% in water (up to ~440 W m⁻² K⁻¹), depending on temperature. These results indicate that the high thermal conductivity of the aluminum skeleton mainly improves conduction (“thermal bridging”), while convection may be locally affected within the pores. This study confirms the capability of the TCP method to discriminate between fluid and composite heat transfer contributions and highlights the potential of additively manufactured aluminum cellular structures for lightweight thermal management applications. Full article

Micropropagation is particularly relevant to A. xanthorrhiza because this crop is traditionally propagated by crown buds, with very low field multiplication rates and a high incidence of systemic pathogens, whereas in vitro culture enables rapid clonal multiplication, sanitation, and long-term conservation of elite and regional genotypes. Micropropagation of A. xanthorrhiza remains hindered by physiological disorders such as hyperhydricity and low shoot proliferation, often associated with limited gas exchange and inadequate culture systems. This study evaluated the effects of different gas exchange regimes and liquid culture methods on in vitro morphogenetic and structural responses. Forced ventilation at 81.3 gas exchanges per day reduced hyperhydricity to 8.3%, while sealed vessels exhibited a hyperhydricity rate of 65.8%. RITA^® bioreactors resulted in the highest shoot multiplication rate (6.5/explant), which is a 48.2% increase over semi-solid medium (4.4 shoots/explant). Additionally, RITA^® systems enhanced leaf expansion, reduced oxidative symptoms, and improved shoot morphology. These findings demonstrate that combining ventilation and immersion control is a promising strategy to improve micropropagation efficiency in A. xanthorrhiza, providing quantitative evidence that complements and extends prior qualitative studies on in vitro ventilation and liquid culture systems. Full article

This study aimed at developing in vitro propagation methods for Crocus sativus L., focusing on the effectiveness of temporary immersion systems (TIS) or bioreactors as an alternative, cost-efficient technique for the large-scale production of saffron corms. The effects of the culture system and cross-cutting on saffron propagation were evaluated. Saffron shoots were cultured in TIS and compared with shoots produced using a conventional semi-solid tissue culture system (SS). The recipient material for automated temporary immersion used in this study was the SETIS™ bioreactor. The growth parameters measured for in vitro culture were the number of neo-formed shoots, shoot height, and the number and size of corms. Based on the present detailed study, the highest shoot multiplication rate (9.1 shoots/explant with 7.2 cm of shoot height) was achieved in the TIS system after shoot cross-cutting, while the lowest multiplication rates were obtained in the semi-solid system (1 shoot/explant with 14.8 cm long shoots). Furthermore, the highest corm formation was obtained in the TIS system, with an average of four corms per explant, with a larger corm weight (10.90 g) and diameter (21.78 mm). These findings highlighted for the first time the efficiency of the bioreactor system combined with cross-cutting of the shoot for efficient and scalable saffron corm propagation, thus making a valuable contribution to sustainable cultivation and conservation strategies while meeting the growing demand for this spice. Full article

Conventional propagation of the highly sought-after ornamental Philodendron erubescens ‘Pink Princess’ is constrained by slow multiplication rates, the risk of unstable variegation, and the limited availability of elite mother stock, making advanced in vitro techniques essential for large-scale production. This research aimed to establish an efficient micropropagation protocol by optimizing the shoot multiplication phase in a twin-flask Temporary Immersion Bioreactor (TIB) system (RITA-type) and subsequently assessing the genetic fidelity of the regenerated plants. Shoot induction was evaluated in a TIB system with an immersion frequency of 4 min every 8 h. Among the tested cytokinins, liquid Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BAP) provided the optimal conditions for shoot proliferation, accounting for approximately 21 shoots/explant. While the TIB system was highly effective for shoot multiplication, it proved suboptimal for root induction. Therefore, rooting was optimized on a semi-solid medium, where MS medium supplemented with 0.5 mg/L indole-3-acetic acid (IAA) was identified as the most effective treatment, yielding an average of 3.0 well-developed roots per explant (1.1 cm in length) within 30 days. For acclimatization, a substrate mix of peat moss, perlite, and vermiculite (2:1:1, v/v/v) ensured a 100% survival rate. Critically, genetic fidelity analysis using RAPD markers revealed monomorphic banding patterns between the micropropagated plantlets and the mother plant (100% similarity), confirming their genetic uniformity and true-to-type nature. The established protocol provides a robust and reliable method for the in vitro propagation of P. erubescens ‘Pink Princess’. This work offers a foundation for developing large-scale commercial production strategies and effectively overcomes many limitations of classical propagation techniques. Full article

This article discusses contemporary strategies to deal with immersed boundary (IB) frameworks useful for analyzing flow–structure interaction in complex settings. It focuses on immense advancements in various fields: biology, oscillation of structures due to fluid flow, deformable materials, thermal processes, settling particles, multiphase systems, and sound propagation. The discussion also involves a review of techniques addressing moving boundary conditions at complex interfaces. Evaluating practical examples and theoretical challenges that have been addressed by these frameworks are another focus of the article. Important results highlight the integration of IB methods with adaptive mesh refinement and high-order accuracy techniques, which enormously improve computational efficiency and precision in modeling complex solid–fluid interactions. The article also describes the evolution of IB methodologies in tackling problems of energy harvesting, bio-inspiration propulsion, and thermal-fluid coupling, which extends IB methodologies broadly in many scientific and industrial areas. More importantly, by bringing together different insights and paradigms from across disciplines, the study highlights the emerging trends in IB methodologies towards solving some of the most intricate challenges within the technical and scientific domains. Full article

Stereoscopic omnidirectional images (SOIs) have gained significant attention for their immersive viewing experience by providing binocular depth with panoramic scenes. However, evaluating their visual quality remains challenging due to its unique spherical geometry, binocular disparity, and viewing conditions. To address these challenges, this paper proposes a dual-branch deep learning framework that integrates spherical structural features and perceptual binocular cues to assess the quality of SOIs without reference. Specifically, the global branch leverages spherical convolutions to capture wide-range spatial distortions, while the local branch utilizes a binocular difference module based on discrete wavelet transform to extract depth-aware perceptual information. A feature complementarity module is introduced to fuse global and local representations for final quality prediction. Experimental evaluations on two public SOIQA datasets—NBU-SOID and SOLID—demonstrate that the proposed method achieves state-of-the-art performance, with PLCC/SROCC values of 0.926/0.918 and 0.918/0.891, respectively. These results validate the effectiveness and robustness of our approach in stereoscopic omnidirectional image quality assessment tasks. Full article

The solid electrolyte interphase (SEI) on the anode of lithium-ion batteries (LIBs) has been studied thoroughly due to its crucial importance to the battery’s long-term performance. At the same time, most studies of the SEI apply ex situ characterization methods, which may introduce artifacts or misinterpretations as they do not investigate the SEI in its unaltered state immersed in liquid battery electrolyte. Thus, in this work, we focus on using the non-destructive combination of electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) and impedance spectroscopy (EIS) in the same electrochemical cell. EQCM-D can not only probe the solidified products of the SEI but also allows for the monitoring of viscoelastic layers and viscosity changes of the electrolyte at the interphase during the SEI formation. EIS complements those results by providing electrochemical properties of the formed interphase. Our results highlight substantial differences in the physical and electrochemical properties between the SEI formed on copper and on amorphous carbon and show how formation parameters and the additive vinylene carbonate (VC) influence their growth. The EQCM-D results show consistently that much thicker SEIs are formed on carbon substrates in comparison to copper substrates. Full article

In this study, we prepared an innovative corrosion-resistant and low-melting-point Al49Sn21Zn16Pb14 alloy, and its microstructure was characterized. The corrosion resistance of the Al49Sn21Zn16Pb14 alloy in a NaCl solution with different concentrations was tested via electrochemical and immersion methods. In addition, the corrosion morphologies and products were analyzed via scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD), and the effects of the NaCl solution’s concentration on the corrosion resistance of the Al49Sn21Zn16Pb14 alloy were studied. The results showed that the melting point of the Al49Sn21Zn16Pb14 alloy was only 356.8 °C, and the melting temperature range was 356.8–377.6 °C. The microstructure of the Al49Sn21Zn16Pb14 alloy was dendritic, eutectic, and peritectic, and it had a face-centered cube (FCC) composition in the solid solution phase. The dendrite structure comprised an Al-rich solid solution primarily in the interdendrites and a Zn-rich solid solution mostly in the dendrites; the eutectic structure mainly consisted of Sn- and Pb-rich solid solutions; and the peritectic structure mainly comprised Zn- and Sn-rich solid solutions. In NaCl solutions of different concentrations, the Al49Sn21Zn16Pb14 alloy is generally corrosive; the corrosion rate of the Al49Sn21Zn16Pb14 alloy in 3.5% NaCl solution was 1.97 × 10⁻² mm/a; and the corrosion surface was loose or cracking. The corrosion products attached to the corrosion surface of the alloys mainly comprised Al and Zn oxides, while Sn and Pb corroded to form Sn and Pb oxides, which dissolved or fell off to form microholes or pores on the corrosion surface of the Al49Sn21Zn16Pb14 alloy. With an increase in the NaCl solution’s concentration, the degree of corrosion products that fell off or dissolved increased, and thus, the Al49Sn21Zn16Pb14 alloy’s corrosion rate increased. In 10.5% and 14% NaCl solutions, the amount of Al oxides in the corrosion products increased, and the locally dense corrosion product that formed on the corrosion surface of the Al49Sn21Zn16Pb14 alloy cracked and could not protect the matrix. The locally dense corrosion products on the surface of the Al49Sn21Zn16Pb14 alloy in NaCl solutions therefore could not improve the corrosion resistance. Full article

This paper generalizes the efficient matrix decomposition method for solving the finite-difference (FD) discretized three-dimensional (3D) Poisson’s equation using symmetric 27-point, 4th-order accurate stencils to adapt more boundary conditions (BCs), i.e., Dirichlet, Neumann, and Periodic BCs. It employs equivalent Dirichlet nodes to streamline source term computation due to BCs. A generalized eigenvalue formulation is presented to accommodate the flexible 4th-order stencil weights. The proposed method significantly enhances computational speed by reducing the 3D problem to a set of independent 1D problems. As compared to the typical matrix inversion technique, it results in a speed-up ratio proportional to $n^4$, where $n$ is the number of nodes along one side of the cubic domain. Accuracy is validated using Gaussian and sinusoidal source fields, showing 4th-order convergence for Dirichlet and Periodic boundaries, and 2nd-order convergence for Neumann boundaries due to extrapolation limitations—though with lower errors than traditional 2nd-order schemes. The method is also applied to vortex-in-cell flow simulations, demonstrating its capability to handle outer boundaries efficiently and its compatibility with immersed boundary techniques for internal solid obstacles. Full article

The thermoplastic composite pipe (TCP) manufacturing process introduces defects that impact performance, such as voids, misalignment, and delamination. Consequently, there is an increasing demand for effective non-destructive testing (NDT) techniques to assess the influence of these manufacturing defects on TCP. The objective is to identify and quantify internal defects at a microscale, thereby improving quality control. A combination of methods, including NDT, has been employed to achieve this goal. The density method is used to determine the void volume fraction. Microscopy and void analysis are performed on pristine samples using optical micrography and scanning electron microscopy (SEM), while advanced techniques like X-ray computer tomography (XCT) and ultrasonic inspections are also applied. The interlayer between the reinforced and inner layers showed good consolidation, though a discontinuity was noted. Microscopy results confirmed solid wall construction, with SEM aligning with the XY axis slice, showing predominant fibre orientation around ±45° and ±90°, and deducing the placement orientation to be ±60°. Comparing immersion, 2D microscopy, and XCT methods provided a comparative approach, even though they could not yield precise void content values. The analysis revealed a void content range of 0–2.2%, with good agreement between microscopy and Archimedes’ methods. Based on XCT and microscopy results, an increase in void diameter at constant volume increases elongation and reduces sphericity. Both methods also indicated that most voids constitute a minority of the total void fraction. To mitigate manufacturing defects, understanding the material’s processing window is essential, which can be achieved through comprehensive material characterization of TCP materials. Full article