Search Results (538)

Thermoplastic polyurethane (TPU) electrospun fiber membranes possess unique micro-nano structures and excellent properties. Adjusting their wettability enables the directional transportation of lubricants. A conventional method for adjusting porosity and wettability involves inducing membrane shrinkage using absolute ethanol and heat treatment. However, the shrinkage response and the corresponding changes in the tensile properties of TPU fiber membranes after induction remain unclear, limiting their applications. Thus, in this study, after being peeled off, the samples were first left to stand at room temperature (RT) for 24 h to release residual stress and stabilize their dimensions, and then treated with dehydrated ethanol at RT and high temperature, respectively, with their shrinkage behaviors observed and recorded. The results showed that TPU nanofiber membranes shrank significantly in absolute ethanol, and the degree of shrinkage was temperature-dependent. The shrinkage rates were 2% and 4% in dehydrated ethanol at room temperature and high temperature, respectively, and heating increased the shrinkage effect by 200%. These findings prove that absolute ethanol causes TPU fibers to shrink, and high temperatures further promote shrinkage. However, although the strong synergistic effect of heat and solvent accelerates shrinkage, it may induce internal structural defects, resulting in the deterioration of mechanical properties. The contraction response induced by anhydrous ethanol stimulation can be used to directionally adjust the local density and modulus of TPU nanofiber membranes, thereby changing the wettability. This approach provides new opportunities for applications in areas such as medium transportation and interface friction reduction in lubrication systems. Full article

The aim of this study was to compare the forces and moments exerted by thermoformed aligners (TFMs) and direct printed aligners (DPAs) on the maxillary left central incisor (21) and adjacent teeth (11, 22) during lingual bodily movement of tooth 21. Methods: An in vitro setup was used to quantify forces and moments on three incisors, which were segmented and fixed onto multi-axis force/moment transducers. TFM were fabricated using 0.76 mm-thick single-layer PET-G foils (ATMOS; American Orthodontics, Sheboygan, WI, USA) and multi-layer TPU foils (Zendura FLX; Bay Materials LLC, Fremont, CA, USA). DPAs were fabricated using TC-85 photopolymer resin (Graphy Inc., Seoul, Republic of Korea). Tooth 21 was planned for bodily displacement by 0.25 mm and 0.50 mm, and six force and moment components were measured on it and the adjacent teeth. Results: TC-85 generated lower forces and moments with fewer unintended forces and moments on the three teeth. TC-85 exerted 0.99 N and 1.53 N of mean lingual force on tooth 21 for 0.25 mm and 0.50 mm activations, respectively; ATMOS produced 3.82 N and 7.70 N, and Zendura FLX produced 3.00 N and 8.23 N of mean lingual force for the same activations, respectively. Bodily movement could not be achieved. Conclusions: The force systems generated by clear aligners are complex and unpredictable. DPA using TC-85 produced lower, more physiological force levels with fewer side effects, which may increase the predictability of tooth movement and enhance treatment outcome. The force levels generated by TFM were considered excessive and not physiologically compatible. Full article

Cranial cruciate ligament (CrCL) rupture is a common orthopedic disorder in dogs, leading to stifle joint instability and progressive osteoarthritis. This study aimed to develop and biomechanically evaluate a novel intra-articular reconstruction system designed to mimic the natural ligament and restore joint stability following CrCL excision. The system consisted of a 3D-printed thermoplastic polyurethane (TPU) graft, cerclage wire, and H-button fixation. Fourteen pelvic limbs from mature mixed-breed cadaveric dogs were used. The inclination angle, dimensions, volume, tensile strength, and elongation of the native CrCL were measured. Seven CrCL-deficient stifles were reconstructed using the proposed system and tested biomechanically. The native CrCL showed a significantly higher tensile strength than the TPU graft; however, the TPU demonstrated a greater flexibility. The reconstruction system successfully stabilized the joint and provided repeatable fixation. Significant correlations were found between CrCL volume and both age and body weight. These findings support the mechanical suitability of the proposed system for ex vivo stifle stabilization and highlight the potential of 3D-printed TPU in ligament reconstruction. Further in vivo studies are recommended to assess long-term performance, including implant integration, tissue remodeling, and clinical outcomes. Full article

A primary objective of this research entails the development of an innovative algorithm capable of tracking a drone in real-time. This objective serves as a fundamental requirement across various applications, including collision avoidance, formation flying, and the interception of moving targets. Nonetheless, regardless of the efficacy of any detection algorithm, achieving 100% performance remains unattainable. Deep neural networks (DNNs) were employed to enhance this performance. To facilitate real-time operation, the DNN must be executed within a Deep Learning Processing Unit (DPU), Neural Processing Unit (NPU), Tensor Processing Unit (TPU), or Graphics Processing Unit (GPU) system on board the UAV. Given the constraints of these processing units, it may be necessary to quantify the DNN or utilize a less complex variant, resulting in an additional reduction in performance. However, precise target detection at each control step is imperative for effective flight path control. By integrating multiple algorithms, the developed system can effectively track UAVs with improved detection performance. Furthermore, this paper aims to establish a versatile Unmanned Aerial System (UAS) development platform constructed using open-source components and possessing the capability to adapt and evolve seamlessly throughout the development and post-production phases. Full article

The rapid expansion of IoT devices poses new challenges for AI-driven services, particularly in terms of energy consumption. Although cloud-based AI processing has been the dominant approach, its high energy consumption calls for more energy-efficient alternatives. Edge computing offers an approach for reducing both latency and energy consumption. In this paper, we propose a methodology for estimating the power consumption of AI accelerators on an embedded edge device. Through experimental evaluations involving GPU- and Edge TPU-based platforms, the proposed method demonstrated estimation errors below 8%. The estimation errors were partly due to unaccounted power consumption from main memory and storage access. The proposed approach provides a foundation for more reliable energy management in AI-powered edge computing systems. Full article

Structural health monitoring in resource-constrained environments demands crack segmentation models that match the accuracy of heavyweight convolutional networks while conforming to the power, memory, and latency limits of watt-level edge devices. This study presents a lightweight dual-attention network, which is a four-stage U-Net compressed to one-quarter of the channel depth and augmented—exclusively at the deepest layer—with a compact dual-attention block that couples channel excitation with spatial self-attention. The added mechanism increases computation by only 19%, limits the weight budget to 7.4 MB, and remains fully compatible with post-training INT8 quantization. On a pixel-labelled concrete crack benchmark, the proposed network achieves an intersection over union of 0.827 and an F1 score of 0.905, thus outperforming CrackTree, Hybrid 2020, MobileNetV3, and ESPNetv2. While refined weight initialization and Dice-augmented loss provide slight improvements, ablation experiments show that the dual-attention module is the main factor influencing accuracy. With 110 frames per second on a 10 W Jetson Nano and 220 frames per second on a 5 W Coral TPU achieved without observable accuracy loss, hardware-in-the-loop tests validate real-time viability. Thus, the proposed network offers cutting-edge crack segmentation at the kiloflop scale, thus facilitating ongoing, on-device civil infrastructure inspection. Full article

Against the backdrop of the increasing penetration rate of new energy year by year, power systems face a continuously growing demand for flexibility. Under the structure of such a new power system, it is essential not only to introduce diverse flexible power sources but also to explore the flexible regulation capabilities of existing conventional power sources. To fully utilize the flexibility of thermal power units (TPUs), this study proposes a real-time optimal scheduling strategy for a wind–thermal energy-storage integrated system with an adaptive time division and variable objectives. Based on the evaluation results of the real-time flexible supply–demand relationship within a regional power grid, the operation modes of TPUs are categorized into three types: economic mode, peak shaving mode, and coordination mode. For each operation mode, corresponding optimization objectives are defined, and an energy storage control strategy is developed to assist in the peak shaving of TPUs. While effectively harnessing the flexibility of TPUs, the proposed method reduces both the frequency and capacity of TPUs entering deep peak shaving. Using data from a province in Northwest China as a case study, simulation calculations and analyses demonstrate that the proposed method increases renewable energy consumption by 314.37 MWh while decreasing system economic benefits by CNY 129,000. Compared with traditional scheduling methods for TPUs to accommodate renewable energy, the system benefit increases by CNY 297,000, and an additional 13.53 MWh of peak wind power is accommodated. These results confirm that the proposed scheduling strategy can significantly enhance the system’s ability to integrate new energy while maintaining its economic efficiency. Full article

Extraterrestrial exploration presents unique challenges for robotic systems, as traditional rigid rovers face limitations in stowage volume, traction on unpredictable terrain, and susceptibility to damage. Soft robotics offers promising solutions through bio-inspired designs that can mimic natural locomotion mechanisms. Here, we present an optimised, spider-inspired soft jumping robot for extraterrestrial exploration that addresses key challenges in soft robotics: actuation efficiency, controllability, and deployment. Drawing inspiration from spider physiology—particularly their hydraulic extension mechanism—we develop a lightweight limb capable of multi-modal behaviour with significantly reduced energy requirements. Our 3D-printed soft actuator leverages pressure-driven collapse for efficient retraction and pressure-enhanced rapid extension, achieving a power-to-weight ratio of 249 W/kg. The integration of a non-backdriveable clutch mechanism enables the system to hold positions with zero energy expenditure—a critical feature for space applications. Experimental characterisation and a subsequent optimisation methodology across various materials, dimensions, and pressures reveal that the robot can achieve jumping heights of up to 1.86 times its body length. The collapsible nature of the soft limb enables efficient stowage during spacecraft transit, while the integrated pumping system facilitates self-deployment upon arrival. This work demonstrates how biologically inspired design principles can be effectively applied to develop versatile robotic systems optimised for the unique constraints of extraterrestrial exploration. Full article

Thermoplastic polyurethane (TPU) combines elastomeric and thermoplastic properties but suffers from insufficient rigidity and strength for structural applications. Herein, we developed novel carbon fiber-reinforced TPU (CF/TPU) composites filaments and utilize melt extrusion for 3D printing to maintain elasticity, while achieving enhanced stiffness and strength through multi scale-the control of fiber content and optimization of printing parameters, reaching a rigid–elastic balance. A systematic evaluation of CF content (0–25%) and printing parameters revealed optimal performance to be at 220–230 °C and 40 mm/s for ensuring proper flow to wet fibers without polymer degradation. Compared with TPU, 20% CF/TPU exhibited 63.65%, 105.51%, and 93.69% improvements in tensile, compressive, and impact strength, respectively, alongside 70.88% and 72.92% enhancements in compression and impact energy absorption. This work establishes a fundamental framework for developing rigid–elastic hybrid materials with tailored energy absorption capabilities through rational material design and optimized additive manufacturing processes. Full article

Thermoplastic polyurethanes (TPUs) have found diverse applications across different industries, which expose the material to various environmental conditions. Among these, UV radiation stands out as one of the most aggressive, leading to significant degradation in polymers. Considering this, this study explores the use of commercial additives, such as polyethylene masterbatches (MB), and their effectiveness as inhibitors of UV radiation-induced degradation. In addition, it investigates the possibility of blending high-performance polymers, such as TPU, with commodity polymers, such as polypropylenes. The prepared blends were evaluated via thermogravimetric analysis, infrared and electron microscopy, hardness and tensile strength assessments, and scanning electron microscopy before and after 320 h of exposure to accelerated aging. The findings suggest that the adequate incorporation of additives in blends can help to reduce the harmful effects caused by UV radiation on the polymeric materials. Full article

Electrospinning with sequential layer deposition has been reported for various applications such as tissue scaffolds, shape memory materials, and separations. However, the effect of layering on the mechanical properties is not fully understood. In this work, layered structures of thermoplastic polyurethane (TPU) and nylon were selected as a model system to investigate the effect of sequential layer deposition on mechanical properties. Evidence of the layered structure was indicated by scanning electron microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR) experiments. Layering TPU with nylon resulted in a 60-fold increase in the Young’s modulus. The Young’s modulus of the layered structure was reasonably predicted by the Voigt rule of mixtures. Furthermore, the Young’s modulus changes without any statistically significant change in elongation at break compared to a single layer of nylon. Thus, the elongation at break was dictated by the stiffer material, despite being present at a lower volume fraction. Overall, electrospinning with sequential layer deposition electrospinning is an effective approach for tuning the mechanical properties and surface chemistry of electrospun materials independently, which may be of interest for applications in tissue engineering and separations. Full article

Placing printed conductive patterns onto nonplanar substrates is a challenging task. In this work, we tested a simple method for depositing inkjet-printed conductive patterns onto 3D-printed pieces with cavities and sharp edges. First, a silver nanoparticle ink was used to print conductive patterns onto a flexible and porous substrate made of electrospun polycaprolactone (PCL). Then, the printed patterns were transferred to 3D-printed pieces made of polylactic acid (PLA) by temperature-promoted adhesion. Finally, the printed patterns were cured to render them conductive. The influence of the number of printed layers on their electrical and mechanical properties was evaluated. The printed patterns were also transferred to flexible substrates, such as thermoplastic polyurethane (TPU) and polyethylene terephthalate (PET) sheets, achieving conductivity after curing. Moreover, the printed patterns were effective for modular interconnection among successive transferred patterns, since it was possible to achieve electrical contact between them during the transfer process. Full article

A series of PPCDL-PEG₁₀₀₀-TPU were prepared by melting method using CO₂ based biodegradable polycarbonate diol (PPCDL) and polyethylene glycol (PEG1000) as soft segments, and hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO) as hard segments. Their structure and properties were characterized to show that the products have nanoscale microphase separation, excellent wear-resistance and high resilience. PPCDL-PEG₁₀₀₀-TPUs have high tensile strength, high elongation at break, controllable hardness and excellent wear resistance when the content of hard segment is about 20%. Compared to PPCDL-TPU with only PPCDL as soft segment, the mechanical properties of TPU increase rather than decrease after the addition of PEG due to the crystallization behavior of PEG units in block copolymers. When the ratios of n_PPCDL:n_PEG are 10:1 and 4:1, the tensile strength of PPCDL-PEG₁₀₀₀-TPU reaches 27.5 MPa and 16.5 MPa (an increase of nearly 200% and 20% than PPCDL-TPU). The elongation at break reaches 1995% and 2485% (an increase of nearly 40% and 75% than PPCDL-TPU). Hardness of the prepared PPCDL-PEG₁₀₀₀-TPUs’ Shore A can be controlled in range of 70~85 by regulating the addition of PEG and their glass transition temperature (Tg) decreases with the increase of the amount of PEG incorporated. All PPCDL-PEG₁₀₀₀-TPUs exhibit good wear resistance with the average Akron wear volume of 12 mm³ after 4000 cycles of experiments according to national standards. PPCDL-PEG₁₀₀₀-TPUs show a high resilience performance with a negligible change in the hysteresis loop area after six cycles of tensile stretching. Furthermore, all PPCDL-PEG₁₀₀₀-TPUs possess high thermal stability, strong hydrophobicity, and low water absorption. This material has excellent application prospects and competitiveness in footwear and shock-absorbing materials. Full article

Analyzing the population’s access to ecosystem services offered by urban greening constitutes a measure of environmental justice, as it directly affects the quality of life and health of the population living in cities. This article is committed to proposing a geoenvironmental model in a geographic information system (GIS), envisaged to estimate the share of urban forests and green spaces in territorial planning units (TPUs), corresponding to neighborhoods of a pilot city, using high-spatial-resolution images of the China–Brazil Earth Resources Satellite (CBERS-4A) and the normalized difference vegetation index (NDVI). These data were combined by means of a Boolean analysis with social vulnerability indicators assessed from census data related to income, education, housing, and sanitation. This model ultimately aims to identify priority areas for urban afforestation in the context of environmental justice and is thus targeted to improve the inhabitants’ quality of life. The municipality of Goiânia, the capital of Goiás state, located in the Brazilian Central–West Region, was chosen as the study area for this experiment. Goiânia presents 19.5% of its urban territory (82.36 km²) covered by vegetation. The analyses indicate an inequity in the distribution of urban forest patches and green areas in this town, where 7.8% of the total TPUs have low priority, 28.2% have moderate to low priority, 42.2% have moderate to high priority, and 21.8% have high priority for urban afforestation. This urban greening imbalance is particularly observed in its most urbanized central nuclei, associated with a peripheralization of social vulnerability. These findings are meant to support initiatives towards sound territorial planning processes designed to promote more sustainable and equal development to ensure environmental justice and combat climate change. Full article

Printed electronics employ established printing methods to create low-cost, mechanically flexible devices including batteries, supercapacitors, sensors, antennas and RFID tags on plastic, paper and textile substrates. This review focuses on the specific contribution of screen printing to that landscape, examining how ink viscosity, mesh selection and squeegee dynamics govern film uniformity, pattern resolution and ultimately device performance. Recent progress in advanced ink systems is surveyed, highlighting carbon allotropes (graphene, carbon nano-onions, carbon nanotubes, graphite), silver and copper nanostructures, MXene and functional oxides that collectively enhance mechanical robustness, electrical conductivity and radio-frequency behavior. Parallel improvements in substrate engineering such as polyimide, PET, TPU, cellulose and elastomers demonstrate the technique’s capacity to accommodate complex geometries for wearable, medical and industrial applications while supporting environmentally responsible material choices such as water-borne binders and bio-based solvents. By mapping two decades of developments across energy-storage layers and functional electronics, the article identifies the key process elements, recurring challenges and emerging sustainable practices that will guide future optimization of screen-printing materials and protocols for high-performance, customizable and eco-friendly flexible devices. Full article