Search Results (277)

To address the critical issue of low cold storage rate of phase-change materials in commercial phase-change modules, this study designed and constructed four heat-conducting-fin-enhanced cold storage blocks featuring different heat-conducting fin configurations: semi-equilateral triangles, semi-squares, semi-regular pentagons, and semi-circles. It systematically investigates the influence of the fin shape and thickness parameters of heat-conducting fins on the cooling charging process of cold storage blocks and clarifies the correlation between heat transfer enhancement and the cooling storage and release performance of refrigerators. The results show that laying copper high-thermal-conductivity fins on the surface of cold storage blocks can significantly accelerate the phase change cold storage rate. Among these structures, the semi-square fin configuration exhibits the optimal enhancement effect: compared with the baseline model without fins, its solidification time is shortened by 35 min. The results indicate that with the increase in fin thickness, the cooling charging time decreases continuously, and there exists a nonlinear positive correlation between cooling charging efficiency and fin thickness. Specifically, the cooling charging time reaches the minimum value when the fin thickness increases to 2.5 mm, while the rate of reduction in cooling charging time slows down significantly after the thickness exceeds 1.5 mm. In addition, the phase-change cold storage block can notably prolong the cooling release duration of the refrigerator. However, although the introduction of heat-conducting fins can improve the cooling charging rate, it will shorten the continuous cooling release time, thus presenting a trade-off between cooling charging efficiency and cooling release duration. The conclusions of this study provide theoretical support and practical guidance for the structural design and performance optimization of efficient commercial phase-change thermal storage and release systems. Full article

The thermal dissipation performance of the radiator is crucial for the stable operation of power electronic devices. Due to excellent thermal performance, copper pin-type heat sink substrates are widely adopted. However, the cold extrusion process for heat sink substrates suffers from low material utilization and high forming loads. To improve material utilization and reduce cold extrusion forming load, four blank shapes (rectangular, trapezoidal, trapezoidal cap, and stepped) were designed using finite-element simulation to investigate the effects of blank shape and placement method with orientation relative to the die cavity on forming quality. Further dimensional optimization was conducted to determine the optimal configuration. The results show that the stepped blank with front orientation exhibits the optimal forming performance, featuring the lowest forming load and the most sufficient pin-fin filling. Compared with back orientation, front orientation achieves higher and more uniform material flow velocity, and significantly reduces forming load. Through dimension optimization, the 7 mm-thick stepped blank is determined as the optimal solution, with the forming load reduced to 15,000 kN (a 35.3% decrease compared to the initial 7.5 mm stepped blank), and both the substrate thickness and pin-fin height meet the design requirements (4.5 mm and 6.5 mm). Experiments verify the feasibility of the optimized scheme, providing technical support for the low-cost, high-quality mass production of copper pin-type heat sink substrates. Full article

The bionic pectoral fin serves as the primary propulsion component of ray-inspired robots. In our previous research, a motion equation was proposed for the real pectoral fin, which can be modeled as a series of NACA airfoil-shaped cross-sections distributed along the spanwise direction. Each cross-section undergoes two coupled rotational motions about its chord line and spanwise rotational axis. To achieve this type of motion, this article introduces a novel bionic pectoral fin mechanism driven by a series of differential gear units. The differential unit generates two coupled rotational motions corresponding to the cross-section of the pectoral fin in motion. A series of interconnected differential units provides a unique topology for the bionic mechanism and can generate a diverse range of motions. Through kinematic analysis, the motion equation was mapped onto the rotational angles of motors in the differential units. The proposed bionic mechanism was then fabricated and subjected to experimental test, demonstrating its effectiveness with a maximum thrust of 0.71 N. The distinctive structure of this bionic mechanism differentiates it from conventional designs and is expected to provide some inspiration for bionic pectoral fins and ray-inspired robots. Full article

This study investigates how financial literacy, FinTech adoption, and financial attitudes shape economic decision-making among millennials in Lebanon, a crisis-affected emerging economy. The study examines whether enhancing financial literacy can strengthen economic resilience through improved financial behavior, with financial attitudes acting as a mediator. Guided by Behavioral Finance Theory, the study employs a quantitative approach using data from 390 Lebanese millennials collected via a structured questionnaire. Structural equation modeling was applied to test direct and mediating effects. Both financial literacy and FinTech adoption were found to significantly influence millennials’ financial behavior, with financial literacy emerging as the stronger predictor. The findings also revealed that financial attitude significantly mediates the link between literacy and behavior, suggesting that financial knowledge alone is insufficient without attitudinal reinforcement. This study fills a critical empirical gap in the MENA region by offering evidence from a highly under-researched, crisis-affected emerging market. It introduces an integrated model combining technological, cognitive, and attitudinal dimensions of financial behavior. The study offers practical implications for policymakers, financial institutions, and international development actors seeking to strengthen financial inclusion and household stability in similar turbulent contexts. Full article

Proton exchange membrane fuel cells (PEMFC) are recognized as promising next-generation energy technology. Yet, their performance is critically limited by inefficient gas transport and water management in conventional flow channels. Current rectangular gas channels (GC) restrict reactive gas penetration into the gas diffusion layer (GDL) due to insufficient longitudinal convection. At the same time, the complex multiphase interactions at the mesoscale pose challenges for numerical modeling. To address these limitations, this study proposes a novel cathode channel design featuring laterally contracted fin-shaped barrier blocks and develops a mesoscopic multiphase coupled transport model using the lattice Boltzmann method combined with the volume-of-fluid approach (LBM-VOF). Through systematic investigation of multiphase flow interactions across channel geometries and GDL surface wettability effects, we demonstrate that the optimized barrier structure induces bidirectional forced convection, enhancing oxygen transport compared to linear channels. Compared with the traditional straight channel, the optimized composite channel achieves a 60.9% increase in average droplet transport velocity and a 56.9% longer droplet displacement distance, while reducing the GDL surface water saturation by 24.8% under the same inlet conditions. These findings provide critical insights into channel structure optimization for high-efficiency PEMFC, offering a validated numerical framework for multiphysics-coupled fuel cell simulations. Full article

Hydrogen-based energy systems require large amounts of high-purity water, motivating thermally driven desalination that can recover low-grade heat. This study evaluates a silica gel–water adsorption chiller–desalination unit as a coupled source of cooling and pre-treated water for electrolysers. A laboratory two-bed system was tested on saline feed using 300 s valve-switching periods at an 80 °C driving temperature and 20–30 °C cooling water. Dynamic vapour sorption measurements provided Dubinin–Astakhov equilibrium and linear driving force kinetic parameters, implemented in a CFD porous bed model via user-defined source terms. Experiments yielded COP values of 0.29–0.41, an SCP of 165 W·kg⁻¹ of adsorbent, and an average distillate production of 1.68–1.82 kg·h⁻¹, while distillate conductivity remained ≈2.3 μS·cm⁻¹. The model reproduced the mean condensate production with a ≈6% underprediction. It was then used to compare six alternative fin geometries with a constant heat-transfer area. Fin-shape modifications changed inter-fin heating by <2 K and cumulative desorbed mass by <0.05%, indicating limited sensitivity to subtle local refinements. Performance gains are more likely to arise from operating conditions and exchanger-scale architecture than from minor fin-shape changes. Full article

This study analyzes the socio-cultural and behavioral determinants of FinTech adoption and access to credit among Ecuadorian SMEs. A probabilistic sample of 600 firms, operating in the services, commerce, information and communication technologies (ICT), and industry sectors, was surveyed to ensure representation of the country’s productive structure. The model integrates financial literacy, institutional trust, and perceived accessibility as key independent variables, with FinTech adoption as a digital behavioral factor and access to credit and credit conditions as the primary dependent outcomes. Using Partial Least Squares Structural Equation Modeling (PLS-SEM), complemented by multi-group invariance tests and cluster analysis, the study evaluates seven hypotheses linking cognitive, perceptual, and digital mechanisms to financing behavior and firm performance. Results show that financial literacy and institutional trust significantly improve access to formal credit, with perceived accessibility acting as a partial mediator. FinTech adoption enhances credit conditions but remains limited among micro and small firms. Based on these findings, the study recommends strengthening financial education programs, simplifying credit procedures to reduce perceived barriers, and developing trust-building regulatory frameworks for digital finance. The results highlight the importance of socio-cultural and behavioral factors in shaping SME financing decisions and contribute to the understanding of financial inclusion dynamics in emerging economies. Full article

Soft robotic grippers provide compliant and adaptive manipulation, but most existing designs address actuation speed, adaptability, modularity, or sensing individually rather than in combination. This paper presents an electro-actuated customizable stacked Fin Ray gripper that integrates these capabilities within a single design. The gripper employs a compact solenoid for fast grasping, multiple vertically stacked Fin Ray segments for improved 3D conformity, and interchangeable silicone or TPU fins that can be tuned for task-specific stiffness and geometry. In addition, a light-guided, vision-based sensing approach is introduced to capture deformation without embedded sensors. Experimental studies—including free-fall object capture and optical shape sensing—demonstrate rapid solenoid-driven actuation, adaptive grasping behavior, and clear visual detectability of fin deformation. Complementary simulations using Cosserat-rod modeling and bond-graph analysis characterize the deformation mechanics and force response. Overall, the proposed gripper provides a practical soft-robotic solution that combines speed, adaptability, modular construction, and straightforward sensing for diverse object-handling scenarios. Full article

Lithium-ion batteries (LIBs) are currently widely used in the electric vehicle sector and have become one of the core components of new energy vehicles. To ensure that the maximum temperature (T_max) and maximum temperature difference (∆T_max) remain within acceptable limits after high-rate discharge, this study proposes a novel air-cooled battery thermal management system (BTMS). This BTMS features innovative design elements in its novel battery case walls and contour-following fin structure. Through physical testing of 21,700 LIB discharges and comparative numerical simulations, the accuracy of the simulation model is ensured. Orthogonal experimental analysis is conducted at four distinct levels for each of the four structural factors involved. The final results demonstrate that the novel battery pack wall and contour-shaped fin structure proposed in this paper significantly enhance the heat dissipation capability of air-cooled BTMS. The proposed Model 9 configuration exhibits optimal thermal performance metrics. The T_max after 3C rate discharge reaches 39.4 °C, with a ∆T_max of 7.4 °C. This study demonstrates significant application potential in the structural implementation of air-cooled BTMSs. Full article

This study presents a unified parametric optimization framework for the thermal design of microchannel spreaders used in high-power processor cooling. The fin geometry is expressed in a shape-agnostic parametric form defined by fin thickness, top and bottom gap widths, and channel height, without prescribing a fixed cross-section. This approach accommodates practical fin profiles ranging from rectangular to tapered and V-shaped, allowing continuous geometric optimization within manufacturability and hydraulic limits. A coupled analytical–numerical model integrates conduction through the spreader base, interfacial resistance across the thermal interface material (TIM), and convection within the coolant channels while enforcing a pressure-drop constraint. The optimization uses a deterministic continuation method with smooth sigmoid mappings and penalty functions to maintain constraint satisfaction and stable convergence across the design space. The total thermal resistance ($R_{\mathrm{tot}}$) is minimized over spreader conductivities $k_s=400–2200$ W m⁻¹ K⁻¹ (copper to CVD diamond), inlet fluid velocities $U_{\mathrm{in}}=0.5–5.5$ m s⁻¹, maximum pressure drops of 10–50 kPa, and fluid pass counts $N_p\in \{1,2,3\}$. The resulting maps of optimized fin dimensions as functions of $k_s$ provide continuous design charts that clarify how material conductivity, flow rate, and pass configuration collectively determine the geometry, minimizing total thermal resistance, thereby reducing chip temperature rise for a given heat load. Full article

In recent years, the design priorities of modern marine propellers have shifted from maximizing efficiency to minimizing vibration-induced noise emissions and improving structural durability. However, an optimized design does not necessarily ensure optimal performance across the full operational range of a vessel. Due to operational constraints such as reduced docking times and regional speed regulations, propellers frequently operate off-design. This deviation from the design point leads to periodic turbulent boundary layer separation on the propeller blades, resulting in increased unsteady pressure fluctuations and, consequently, elevated hydroacoustic noise emissions. To mitigate these effects, bio-inspired modifications have been investigated as a means of improving flow characteristics and reducing pressure fluctuations. Tubercles, characteristic protrusions along the leading edge of humpback whale fins, have been shown to enhance lift characteristics beyond the stall angle by modifying the flow separation pattern. However, their influence on transient pressure fluctuations and the associated hydroacoustic behavior of marine propellers remains insufficiently explored. In this study, we apply the concept of tubercles to the blades of a hubless propeller, also referred to as a rim-drive propeller. We analyze the pressure fluctuations on the blades and in the wake by comparing conventional propeller blades with those featuring tubercles. The flow fields of both reference and tubercle-modified blades were simulated using the Stress Blended Eddy Simulation (SBES) turbulence model to highlight differences in the flow field. In both configurations, multiple helix-shaped vortex systems form in the propeller wake, but their decay characteristics vary, with the vortex structures collapsing at different distances from the propeller center. Additionally, Proper Orthogonal Decomposition (POD) analysis was employed to isolate and analyze the periodic, coherent flow structures in each case. Previous studies on the flow field of hubless propellers have demonstrated a direct correlation between transient pressure fluctuations in the flow field and the resulting noise emissions. It was demonstrated that the tubercle modification significantly reduces pressure fluctuations both on the propeller blades and in the wake flow. In the analyzed case, a reduction in pressure fluctuations by a factor of three to ten for the different BPF orders was observed within the wake flow. Full article

The digitalization of finance has accelerated the diffusion of FinTech and raised new questions about how AI, data security and blockchain shape consumer behaviour. This article examines current FinTech users, focusing on mobile banking, security perceptions, AI-enabled personalisation and trust in blockchain. A structured online survey of 191 adult users was analysed with descriptive statistics, chi-square tests and three multiple linear regression models. Results show that adoption is overwhelmingly mobile centric: 84.8% primarily use mobile banking applications, accessed almost exclusively via smartphones (96.9%). Data security is the dominant decision criterion, rated “very important” by 83.3% of respondents. While 70.1% believe AI can substantially improve the FinTech experience, trust depends on transparent explanations of how algorithms operate and on guarantees of personal data protection. Regression models indicate that usage intensity is higher among younger, higher-income users and those who perceive simplified interfaces as encouraging, whereas positive views of AI are broadly shared and not segment-specific. Trust in blockchain is linked to a pro-technology mindset rather than to socio-demographic or urban–rural differences. The findings highlight “secure convenience” and explainable AI as central conditions for sustainable FinTech engagement. Full article

The low thermal conductivity of phase-change materials (PCMs) remains a key limitation in latent heat thermal energy storage systems, leading to slow melting and incomplete energy recovery. To address this challenge, this study explores extended Y-Fin geometries as a novel heat transfer enhancement strategy within a concentric-tube latent heat thermal energy storage configuration. Six fin designs, derived from a baseline Y-shaped structure, were numerically compared to assess their influence on the melting and solidification behavior of stearic acid. A two-dimensional transient enthalpy–porosity model was developed and rigorously verified through grid, temporal, and residual convergence analyses. The results indicate that fin geometry plays a critical role in enhancing heat transfer within the PCM domain. The extended Y-Fin configuration achieved the fastest melting time, 28% shorter than the baseline Y-Fin case, due to improved thermal penetration and bottom-region accessibility. Additionally, the thermal performance was evaluated using nano-enhanced PCMs (10% Al₂O₃ and CuO in stearic acid) and paraffin wax. The addition of Al₂O₃ nanoparticles significantly improved thermal conductivity, while paraffin wax exhibited the shortest melting duration due to its lower melting point and latent heat. This study introduces an innovative fin architecture combining extended conduction paths and improved convective reach for efficient latent heat storage systems. Full article

The parasitic Sub-Fin, beneath the stacked nanosheet FETs, limits both leakage and heat dissipation, acting as the bottleneck for improving the performance of NS-FETs. A Sub-Fin edit technology based on remote plasma etching is proposed to modulate the formation of the Sub-Fin. By controlling the process parameters, the Sub-Fin profile can be continuously modulated from “arrow-shaped” to “bell-shaped,” which provides the flexibility to improve the thermal resistance and reduce the parasitic Sub-Fin-induced degradation, making it suitable for low-power and high-performance applications, respectively. The Sub-Fin edit technology is fully compatible with mature Gate-All-Around (GAA) fabrication processes and offers a feasible approach to balancing the trade-off between Sub-Fin degradation and heat dissipation through the Sub-Fin. Full article

The rapid growth of financial technology (FinTech) has created new opportunities to promote environmentally responsible consumption. Yet, little is known about the factors that shape consumer trust in green FinTech platforms, which is crucial for their adoption and long-term impact. This study develops and tests a partial least squares structural equation model (PLS-SEM) integrating sustainability and technology determinants of trust. Survey data from 240 consumers were analyzed. Results show that green transparency, platform security and privacy, and ease of use significantly enhance perceived credibility, while social influence and perceived environmental responsibility increase green perceived value. In turn, perceived credibility reduces perceived risk and promotes trust. Trust is also strengthened by environmental responsibility, green perceived value, and platform innovativeness, but weakened by perceived risk. All hypothesized relationships were statistically significant. The findings highlight the importance of credible sustainability communication, high level security, and social endorsement in building trust for green FinTech services. Full article