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Search Results (134)

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18 pages, 273 KiB  
Review
Incorporation of E-Waste Plastics into Asphalt: A Review of the Materials, Methods, and Impacts
by Sepehr Mohammadi, Dongzhao Jin, Zhongda Liu and Zhanping You
Encyclopedia 2025, 5(3), 112; https://doi.org/10.3390/encyclopedia5030112 - 1 Aug 2025
Viewed by 153
Abstract
This paper presents a comprehensive review of the environmentally friendly management and reutilization of electronic waste (e-waste) plastics in flexible pavement construction. The discussion begins with an overview of e-waste management challenges and outlines key recycling approaches for converting plastic waste into asphalt-compatible [...] Read more.
This paper presents a comprehensive review of the environmentally friendly management and reutilization of electronic waste (e-waste) plastics in flexible pavement construction. The discussion begins with an overview of e-waste management challenges and outlines key recycling approaches for converting plastic waste into asphalt-compatible materials. This review then discusses the types of e-waste plastics used for asphalt modification, their incorporation methods, and compatibility challenges. Physical and chemical treatment techniques, including the use of free radical initiators, are then explored for improving dispersion and performance. Additionally, in situations where advanced pretreatment methods are not applicable due to cost, safety, or technical constraints, the application of alternative approaches, such as the use of low-cost complementary additives, is discussed as a practical solution to enhance compatibility and performance. Finally, the influence of e-waste plastics on the conventional and rheological properties of asphalt binders, as well as the performance of asphalt mixtures, is also evaluated. Findings indicate that e-waste plastics, when combined with appropriate pretreatment methods and complementary additives, can enhance workability, cold-weather cracking resistance, high-temperature anti-rutting performance, and resistance against moisture-induced damage while also offering environmental and economic benefits. This review highlights the potential of e-waste plastics as sustainable asphalt modifiers and provides insights across the full utilization pathway, from recovery to in-field performance. Full article
(This article belongs to the Collection Sustainable Ground and Air Transportation)
19 pages, 1165 KiB  
Article
Expansion of Mechanical Biological Residual Treatment Plant with Fermentation Stage for Press Water from Organic Fractions Involving a Screw Press
by Rzgar Bewani, Abdallah Nassour, Thomas Böning, Jan Sprafke and Michael Nelles
Recycling 2025, 10(4), 141; https://doi.org/10.3390/recycling10040141 - 16 Jul 2025
Viewed by 279
Abstract
A three-year optimization study was conducted at a mechanical biological treatment plant with the aim of enhancing organic fractions recovery from mechanically separated fine fractions (MSFF) of residual waste using a screw press. The study aimed to optimize key operating parameters for the [...] Read more.
A three-year optimization study was conducted at a mechanical biological treatment plant with the aim of enhancing organic fractions recovery from mechanically separated fine fractions (MSFF) of residual waste using a screw press. The study aimed to optimize key operating parameters for the employed screw press, such as pressure, liquid-to-MSFF, feeding quantity per hour, and press basket mesh size, to enhance volatile solids and biogas recovery in the generated press water for anaerobic digestion. Experiments were performed at the full-scale facility to evaluate the efficiency of screw press extraction with other pretreatment methods, like press extrusion, wet pulping, and hydrothermal treatment. The results indicated that hydrolysis of the organic fractions in MSFF was the most important factor for improving organic extraction from the MSFF to press water for fermentation. Optimal hydrolysis efficiency was achieved with a digestate and process water-to-MSFF of approximately 1000 L/ton, with a feeding rate between 8.8 and 14 tons per hour. Increasing pressure from 2.5 to 4.0 bar had minimal impact on press water properties or biogas production, regardless of the press basket size. The highest volatile solids (29%) and biogas (50%) recovery occurred at 4.0 bar pressure with a 1000 L/ton liquid-to-MSFF. Further improvements could be achieved with longer mixing times before pressing. These findings demonstrate the technical feasibility of the pressing system for preparing an appropriate substrate for the fermentation process, underscoring the potential for optimizing the system. However, further research is required to assess the cost–benefit balance. Full article
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24 pages, 2692 KiB  
Article
Fine-Grained Dismantling Decision-Making for Distribution Transformers Based on Knowledge Graph Subgraph Contrast and Multimodal Fusion Perception
by Li Wang, Yujia Hu, Zhiyao Zheng, Guangqiang Wu, Jianqin Lin, Jialing Li and Kexin Zhang
Electronics 2025, 14(14), 2754; https://doi.org/10.3390/electronics14142754 - 8 Jul 2025
Viewed by 363
Abstract
Distribution transformers serve as critical nodes in smart grids, and management of their recycling plays a vital role in the full life-cycle management for electrical equipment. However, the traditional manual dismantling methods often exhibit a low metal recovery efficiency and high levels of [...] Read more.
Distribution transformers serve as critical nodes in smart grids, and management of their recycling plays a vital role in the full life-cycle management for electrical equipment. However, the traditional manual dismantling methods often exhibit a low metal recovery efficiency and high levels of hazardous substance residue. To facilitate green, cost-effective, and fine-grained recycling of distribution transformers, this study proposes a fine-grained dismantling decision-making system based on a knowledge graph subgraph comparison and multimodal fusion perception. First, a standardized dismantling process is designed to achieve refined transformer decomposition. Second, a comprehensive set of multi-dimensional evaluation metrics is established to assess the effectiveness of various recycling strategies for different transformers. Finally, through the integration of multimodal perception with knowledge graph technology, the system achieves automated sequencing of the dismantling operations. The experimental results demonstrate that the proposed method attains 99% accuracy in identifying recyclable transformers and 97% accuracy in auction-based pricing. The residual oil rate in dismantled transformers is reduced to below 1%, while the metal recovery efficiency increases by 40%. Furthermore, the environmental sustainability and economic value are improved by 23% and 40%, respectively. This approach significantly enhances the recycling value and environmental safety of distribution transformers, providing effective technical support for smart grid development and environmental protection. Full article
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32 pages, 1967 KiB  
Review
Energy Valorization and Resource Recovery from Municipal Sewage Sludge: Evolution, Recent Advances, and Future Prospects
by Pietro Romano, Adriana Zuffranieri and Gabriele Di Giacomo
Energies 2025, 18(13), 3442; https://doi.org/10.3390/en18133442 - 30 Jun 2025
Viewed by 516
Abstract
Municipal sewage sludge, a by-product of urban wastewater treatment, is increasingly recognized to be a strategic resource rather than a disposal burden. Traditional management practices, such as landfilling, incineration, and land application, are facing growing limitations due to environmental risks, regulatory pressures, and [...] Read more.
Municipal sewage sludge, a by-product of urban wastewater treatment, is increasingly recognized to be a strategic resource rather than a disposal burden. Traditional management practices, such as landfilling, incineration, and land application, are facing growing limitations due to environmental risks, regulatory pressures, and the underuse of the sludge’s energy and nutrient potential. This review examines the evolution of sludge management, focusing on technologies that enable energy recovery and resource valorization. The transition from linear treatment systems toward integrated biorefineries is underway, combining biological, thermal, and chemical processes. Anaerobic digestion remains the most widely used energy-positive method, but it is significantly improved by processes such as thermal hydrolysis, hydrothermal carbonization, and wet oxidation. Among these, hydrothermal carbonization stands out for its scalability, energy efficiency, and phosphorus-rich hydrochar production, although implementation barriers remain. Economic feasibility is highly context-dependent, being shaped by capital costs, energy prices, product markets, and policy incentives. This review identifies key gaps, including the need for standardized treatment models, decentralized processing hubs, and safe residual management. Supportive regulation and economic instruments will be essential to facilitate widespread adoption. In conclusion, sustainable sludge management depends on modular, integrated systems that recover energy and nutrients while meeting environmental standards. A coordinated approach across technology, policy, and economics is vital to unlock the full value of this critical waste stream. Full article
(This article belongs to the Section B: Energy and Environment)
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20 pages, 690 KiB  
Article
Using Graph-Enhanced Deep Reinforcement Learning for Distribution Network Fault Recovery
by Yueran Liu, Peng Liao and Yang Wang
Machines 2025, 13(7), 543; https://doi.org/10.3390/machines13070543 - 23 Jun 2025
Viewed by 452
Abstract
Fault recovery in distribution networks is a complex, high-dimensional decision-making task characterized by partial observability, dynamic topology, and strong interdependencies among components. To address these challenges, this paper proposes a graph-based multi-agent deep reinforcement learning (DRL) framework for intelligent fault restoration in power [...] Read more.
Fault recovery in distribution networks is a complex, high-dimensional decision-making task characterized by partial observability, dynamic topology, and strong interdependencies among components. To address these challenges, this paper proposes a graph-based multi-agent deep reinforcement learning (DRL) framework for intelligent fault restoration in power distribution networks. The restoration problem is modeled as a partially observable Markov decision process (POMDP), where each agent employs graph neural networks to extract topological features and enhance environmental perception. To address the high-dimensionality of the action space, an action decomposition strategy is introduced, treating each switch operation as an independent binary classification task, which improves convergence and decision efficiency. Furthermore, a collaborative reward mechanism is designed to promote coordination among agents and optimize global restoration performance. Experiments on the PG&E 69-bus system demonstrate that the proposed method significantly outperforms existing DRL baselines. Specifically, it achieves up to 2.6% higher load recovery, up to 0.0 p.u. lower recovery cost, and full restoration in the midday scenario, with statistically significant improvements (p<0.05 or p<0.01). These results highlight the effectiveness of graph-based learning and cooperative rewards in improving the resilience, efficiency, and adaptability of distribution network operations under varying conditions. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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18 pages, 1628 KiB  
Article
A More Environmentally Friendly Method for Pulp Processing Using DES-like Mixtures: Comparison of Physical Properties with Oxygen Bleached Pulp
by Lota Chrvalová, Veronika Jančíková, Ida Skotnicová, Michal Jablonský and Štefan Šutý
Processes 2025, 13(6), 1930; https://doi.org/10.3390/pr13061930 - 18 Jun 2025
Viewed by 1959
Abstract
The traditional papermaking process uses petroleum-based additives, which raise environmental concerns. As a result, these concerns have attracted the scientific community to explore green additives by introducing environmentally friendly cellulose modifications as additives to the papermaking process. A promising way to process pulp [...] Read more.
The traditional papermaking process uses petroleum-based additives, which raise environmental concerns. As a result, these concerns have attracted the scientific community to explore green additives by introducing environmentally friendly cellulose modifications as additives to the papermaking process. A promising way to process pulp is the application of deep eutectic solvent-like mixtures, which expand new possibilities for delignification processes. This article aims to characterize the physical properties of pulps modified with deep eutectic solvent-like mixtures and to compare these properties to untreated softwood kraft pulp and pulp obtained after oxygen delignification (commercially available pulp; obtained from Mondi Štětí a.s.). The physical properties (mechanical and optical) of the original pulp and delignified pulps were evaluated based on the degree of beating (Schopper–Riegler degree), zeta potential, water retention value, tensile strength, modulus of elasticity, and whiteness. Technology employing deep eutectic solvent-like mixtures shows great promise for sustainable pulp production; however, its full-scale adoption will require further research focused on process optimization, solvent recovery, and economic cost reduction. Full article
(This article belongs to the Special Issue Circular Economy on Production Processes and Systems Engineering)
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12 pages, 821 KiB  
Review
The Potential Use of Fibrin Sealants in Burn Wound Management: A Comprehensive Review of Experimental and Clinical Studies
by Christina Nikolaou, Maximos Frountzas, Emmanouil I. Kapetanakis, Dimitrios Stefanoudakis, Nikolaos A. Papadopulos, Stylianos Kykalos, Dimitrios Schizas and Dimitrios Iliopoulos
Eur. Burn J. 2025, 6(2), 32; https://doi.org/10.3390/ebj6020032 - 5 Jun 2025
Viewed by 453
Abstract
Fibrin sealants have been implemented in the management of burn wounds. They can be used either in combination with skin grafts for full-thickness burns or alone for treating superficial and deep dermal burns. The aim of this review was to provide critical insights [...] Read more.
Fibrin sealants have been implemented in the management of burn wounds. They can be used either in combination with skin grafts for full-thickness burns or alone for treating superficial and deep dermal burns. The aim of this review was to provide critical insights regarding the efficacy of fibrin sealants in enhancing wound healing, improving graft adherence, and reducing complications. Therefore, evidence from experimental models and clinical trials was synthesized, underscoring the transformative role of fibrin sealants in modern burn care. This comprehensive review includes recent evidence on the potential benefits of fibrin sealants in the management of superficial and deep dermal or full-thickness burn injuries. Clinical and experimental evidence underscores some benefits in utilizing fibrin sealants in the management of superficial and deep dermal burn injuries, or in combination with skin grafts in full-thickness burns. Furthermore, fibrin sealants diminish postoperative pain and facilitate quick recovery for daily activities; however, controversy regarding their cost still remains. This review concludes that fibrin sealants could serve as a safe and effective therapeutic option for burn wound management. The safety and efficacy of their utilization, along with their wide availability and easiness to use, could make them an alternative treatment choice when a specialized plastic surgery service is not available, or in the emergency setting across different healthcare systems. Full article
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11 pages, 567 KiB  
Review
Are There Unique Barriers and Opportunities for Access to Endoscopic Spine Surgery in Low-Income Countries? A Narrative Review
by Adham M. Khalafallah, Sara Diez, Long Di, Saqib Hasan, Sanjay Konakondla, Osama N. Kashlan, Peter Derman, Mark Mahan, Raymond J. Gardocki, Albert Telfeian, Christoph P. Hofstetter and Gregory Basil
J. Clin. Med. 2025, 14(11), 3876; https://doi.org/10.3390/jcm14113876 - 30 May 2025
Viewed by 619
Abstract
Full endoscopic spine surgery (FESS) offers an ultra-minimally invasive solution for addressing many different degenerative spine pathologies. While FESS has demonstrated strong evidence for faster recovery, reduced hospital stays, fewer complications, and potentially lower overall costs, FESS remains underutilized in low-income countries (LICs). [...] Read more.
Full endoscopic spine surgery (FESS) offers an ultra-minimally invasive solution for addressing many different degenerative spine pathologies. While FESS has demonstrated strong evidence for faster recovery, reduced hospital stays, fewer complications, and potentially lower overall costs, FESS remains underutilized in low-income countries (LICs). This narrative review synthesizes the existing literature to evaluate access to FESS in LICs, highlighting challenges such as a lack of trained neurosurgeons and orthopedic surgeons, insufficient access to specialized equipment, capital costs, and limited representation in research. A systematic literature search identified only a handful of relevant studies, underscoring the scarcity of data on FESS in LICs. Findings reveal stark disparities in training opportunities and equipment availability, with less than 25% of LIC facilities equipped with the essential tools. This review advocates for international collaboration, increased funding, cost reduction, and targeted research to bridge these gaps. Innovative solutions such as virtual training platforms may help overcome current limitations. Addressing these challenges is essential to leveraging FESS’s potential to mitigate the burden of spinal disorders in LICs and advance global health equity. Full article
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21 pages, 4354 KiB  
Article
Design and Validation of a SiC-Based Single-to-Three-Phase Converter for Low-Voltage Distribution Systems
by Boohyun Shin, Changhwan Kim, Hyeseon Lee and Sungyun Choi
Appl. Sci. 2025, 15(10), 5590; https://doi.org/10.3390/app15105590 - 16 May 2025
Cited by 1 | Viewed by 357
Abstract
In areas such as remote, rural, and mountainous regions, supplying low-voltage three-phase power has traditionally required distribution line extension and transformer installation. However, these areas often yield low electricity revenues, making cost recovery difficult for utilities. To address this challenge, this paper proposes [...] Read more.
In areas such as remote, rural, and mountainous regions, supplying low-voltage three-phase power has traditionally required distribution line extension and transformer installation. However, these areas often yield low electricity revenues, making cost recovery difficult for utilities. To address this challenge, this paper proposes a Single-to-Three-Phase Converter (STPC) capable of converting single-phase low-voltage input into three-phase output for use in low-voltage distribution systems. The STPC topology employs a single-phase half-bridge AC–DC stage and a three-phase full-bridge inverter stage using SiC-MOSFETs. To validate the system, simulations and experiments were conducted under various load conditions, including unbalanced, nonlinear, and motor loads. The results show that STPC maintains output stability while minimizing impact on the existing grid. The findings demonstrate STPC’s feasibility as an alternative to conventional line extension and transformer installation, with potential for application in grid-forming and low-voltage distribution current (LVDC) systems. Full article
(This article belongs to the Special Issue Current Research and Future Trends in Power Electronics Applications)
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25 pages, 5491 KiB  
Article
Exploring the Economic Hypothetical for Downhill Belt Conveyors Equipped with Three-Phase Active Front-End Load Converters
by Daniel Chelopo and Kapil Gupta
Technologies 2025, 13(5), 185; https://doi.org/10.3390/technologies13050185 - 5 May 2025
Viewed by 680
Abstract
This paper integrates empirical assessments of energy recovery in downhill belt conveyor systems with rigorous theoretical modeling and economic analysis. An alternative approach for capturing and transforming the potential energy of a descending conveyor into electrical energy is proposed using an active front-end [...] Read more.
This paper integrates empirical assessments of energy recovery in downhill belt conveyor systems with rigorous theoretical modeling and economic analysis. An alternative approach for capturing and transforming the potential energy of a descending conveyor into electrical energy is proposed using an active front-end (AFE) load energy recovery system. Adjusting the drive configuration from a standard direct-on-line (DOL) system to a regenerative AFE converter, the conveyor’s excess kinetic energy can be fed back into the grid. The investigation shows that operating a 300 kW downhill conveyor at full capacity would consume about 142,800 kWh per month in a conventional setup. However, at 90% of the maximum capacity over 17 h per day (~476 h per month), the conveyor with an AFE system produces a regenerative power of 188 kW (negative demand), yielding a net generation of 89,488 kWh per month. The results indicate that integrating a regenerative AFE control system can achieve energy savings of approximately 37% compared to a non-regenerative system. The key economic indicators, including lifecycle cost, payback period, and net present value, confirm the financial viability of the proposed system over a 20-year span. Full article
(This article belongs to the Section Manufacturing Technology)
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11 pages, 629 KiB  
Review
Comparison of Outcomes Among Neurovascular Patients Managed in Dedicated Neurological Intensive Care Units vs. General Intensive Care Units
by Joanna M. Roy, Basel Musmar, Nassos Tziviskos, Saarang Patel, Roberto DeLeon, Ashley Thommana, Shady Mina, Stavropoula I. Tjoumakaris, Michael. Reid Gooch, Robert H. Rosenwasser and Pascal M. Jabbour
J. Clin. Med. 2025, 14(9), 3090; https://doi.org/10.3390/jcm14093090 - 29 Apr 2025
Viewed by 611
Abstract
Background/Objectives: Patients with neurovascular conditions often require multidisciplinary management to optimize recovery. Our systematic review identifies literature comparing outcomes among neurovascular patients managed at dedicated neurological intensive care units (ICUs) compared to general ICUs. Methods: PubMed was searched to identify articles [...] Read more.
Background/Objectives: Patients with neurovascular conditions often require multidisciplinary management to optimize recovery. Our systematic review identifies literature comparing outcomes among neurovascular patients managed at dedicated neurological intensive care units (ICUs) compared to general ICUs. Methods: PubMed was searched to identify articles that reported outcomes among patients managed at dedicated neurological ICUs versus general ICUs. Articles that reported outcomes among patients with neurovascular conditions were included. Articles that reported outcomes among patients managed at stroke units were excluded. The Newcastle Ottawa Scale (NOS) was used to assess for risk of bias across individual studies. Results: After a title and abstract screen followed by a full-text review, seven studies met criteria for inclusion. These studies reported outcomes among patients managed for intracerebral hemorrhage (ICH), acute ischemic stroke (AIS) and aneurysmal subarachnoid hemorrhage (aSAH). Two studies reported lower mortality, improved functional outcome and reduced costs among patients with ICH who were managed at dedicated neurological ICUs. Among patients with aSAH, only less-severe cases experienced better functional outcome after management at dedicated neurological ICUs. Six out of seven studies were considered high quality. Conclusions: Our review highlights the potential benefits of receiving care at dedicated neurological ICUs, as evidenced by lower mortality, improved functional outcome and reduced costs in patients with ICH and low-grade aSAH. However, future research is necessary to clarify whether dedicated neurological ICU care confers significant advantage over general ICUs among patients with AIS and other neurovascular conditions. Full article
(This article belongs to the Special Issue Neurocritical Care: Clinical Advances and Practice Updates)
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13 pages, 2299 KiB  
Article
Machine Learning Introduces Electrophysiology Assessment as the Best Predictor for the Recovery Prognosis of Spinal Cord Injury Patients for Personalized Rehabilitation Approaches
by Dionysia Chrysanthakopoulou, Charalampos Matzaroglou, Eftychia Trachani and Constantinos Koutsojannis
Appl. Sci. 2025, 15(8), 4578; https://doi.org/10.3390/app15084578 - 21 Apr 2025
Cited by 1 | Viewed by 1047
Abstract
The strong correlation between evoked potentials (EPs) and American Spinal Injury Association (ASIA) scores in individuals with spinal cord injury (SCI) suggests that EPs may serve as reliable predictive markers for rehabilitation progress. Numerous studies have confirmed a relationship between variations in somatosensory [...] Read more.
The strong correlation between evoked potentials (EPs) and American Spinal Injury Association (ASIA) scores in individuals with spinal cord injury (SCI) suggests that EPs may serve as reliable predictive markers for rehabilitation progress. Numerous studies have confirmed a relationship between variations in somatosensory evoked potentials (SSEPs) and ASIA scores, especially in the early stages of SCI. Machine learning’s (ML’s) increasing importance in medicine is driven by the growing availability of health data and improved algorithms. It enables the creation of predictive models for disease diagnosis, progression prediction, personalized treatment, and improved healthcare efficiency. Data-driven approaches can significantly improve patient care, reduce costs, and facilitate personalized medicine. The meticulous analysis of medical data is crucial for timely disease identification, leading to effective symptom management and appropriate treatment. This study applies artificial intelligence to identify predictors of SCI progression, as measured by the disability index, ASIA impairment scale (AIS), and final motor recovery. We aim to clarify the prognostic role of electrophysiological testing (SSEPs, MEPs, and nerve conduction studies (NCSs)) in SCI. We analyzed data from a medical database of 123 records. We developed an ML-based intelligent system, utilizing ensemble algorithms combining decision trees and neural network approaches, to predict SCI recovery. Our evaluation showed SEP accuracies of 90% for motor recovery prediction and 80% for AIS scale determination, comparable to full electrophysiology evaluation accuracies of 93% and 89%, respectively, and generally superior results compared to MEP and NCS results. EPs emerged as the best predictors, comparable to a comprehensive electrophysiology assessment, significantly improving accuracy compared to clinical findings alone. An electrophysiological assessment, when available, increased overall accuracy for final motor recovery prediction to 93% (from a maximum of 75%) and, for ASIA score determination, to 89% (from a maximum of 66%). Further validation is needed with a larger dataset. Future research should validate that sensory electrophysiology assessment is a less expensive, portable, and simpler alternative to other prognostic tests and more effective than clinical assessments, like the AIS, biomarker for SCI, and personalized rehabilitation planning. Full article
(This article belongs to the Special Issue Advanced Physical Therapy for Rehabilitation)
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21 pages, 11384 KiB  
Article
Optimization of the Recycling Process for Aligned Short Carbon Fiber TuFF Composites
by Uday Kiran Balaga, Aydin Gunes, Tekin Ozdemir, Chris Blackwell, Mark Davis, Steven Sauerbrunn, Lukas Fuessel, Joseph M. Deitzel and Dirk Heider
Recycling 2025, 10(2), 55; https://doi.org/10.3390/recycling10020055 - 1 Apr 2025
Cited by 1 | Viewed by 931
Abstract
Recycling of carbon fibers enables a sustainable feedstock for industrial applications of high-performance composite materials. This allows light weighting with recycled carbon fibers due to their superior mechanical properties while reducing the high embodied energy and cost of virgin carbon fiber composites. This [...] Read more.
Recycling of carbon fibers enables a sustainable feedstock for industrial applications of high-performance composite materials. This allows light weighting with recycled carbon fibers due to their superior mechanical properties while reducing the high embodied energy and cost of virgin carbon fiber composites. This study optimizes a pyrolysis cycle for fiber recovery of an aerospace-grade thermoset prepreg and a cleaning (oxidation) step to minimize fiber degradation and left-over resin residue, enabling dispersion and alignment of the recycled, discontinuous fibers in the Tailorable Universal Feedstock for Forming alignment process. The study balances the influence of the optimized thermal cycle (pyrolysis + oxidation step) on recycled carbon fiber strength retention with the ability to disperse at the filament level to create aligned, recycled carbon fiber composite samples with high fiber volume fraction. The optimized thermal cycle for efficient fiber recovery applied a pyrolysis step at 500 °C for 4 h in an inert gas environment and an additional oxidation step at the same temperature for 100 min. This resulted in ~20% strength degradation of the fiber compared to the virgin fiber. The processed recycled composite achieved 44% fiber volume fraction with full modulus translation (~128 GPa) compared to the virgin continuous composite with strength translation (~870 MPa), reaching ~50%. Full article
(This article belongs to the Special Issue Challenges and Opportunities in Plastic Waste Management)
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24 pages, 6826 KiB  
Article
Preparation of NiO NWs by Thermal Oxidation for Highly Selective Gas-Sensing Applications
by Marwa Ben Arbia, Sung-Ho Kim, Jun-Bo Yoon and Elisabetta Comini
Sensors 2025, 25(7), 2075; https://doi.org/10.3390/s25072075 - 26 Mar 2025
Cited by 2 | Viewed by 837
Abstract
This paper presents a novel approach for fabricating porous NiO films decorated with nanowires, achieved through sputtering followed by thermal oxidation of a metallic layer. Notably, we successfully fabricate NiO nanowires using this simple and cost-effective method, demonstrating its potential applicability in the [...] Read more.
This paper presents a novel approach for fabricating porous NiO films decorated with nanowires, achieved through sputtering followed by thermal oxidation of a metallic layer. Notably, we successfully fabricate NiO nanowires using this simple and cost-effective method, demonstrating its potential applicability in the gas-sensing field. Furthermore, by using the film of our nanowires, we are able to easily prepare NiO sensors and deposit the required Pt electrodes directly on the film. This is a key advantage, as it simplifies the fabrication process and makes it easier to integrate the sensors into practical gas-sensing devices without the need for nanostructure transfer or intricate setups. Scanning electron microscopy (SEM) reveals the porous structure and nanowire formation, while X-ray diffraction (XRD) confirms the presence of the NiO phase. As a preliminary investigation, the gas-sensing properties of NiO films with varying thicknesses were evaluated at different operating temperatures. The results indicate that thinner layers exhibit superior performances. Gas measurements confirm the p-type nature of the NiO samples, with sensors showing high responsiveness and selectivity toward NO2 at an optimal temperature of 200 °C. However, incomplete recovery is observed due to the high binding energy of NO2 molecules. At higher temperatures, sufficient activation energy enables a full sensor recovery but with reduced response. The paper discusses the adsorption–desorption reaction mechanisms on the NiO surface, examines how moisture impacts the enhanced responsiveness of Pt-NiO (2700%) and Au-NiO (400%) sensors, and highlights the successful fabrication of NiO nanowires through a simple and cost-effective method, presenting a promising alternative to more complex approaches. Full article
(This article belongs to the Special Issue Nanomaterials for Chemical Sensors 2023)
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17 pages, 2790 KiB  
Article
Cumulative Energy Demand Analysis of Commercial and Hybrid Metal-Composite Gears at Different End-of-Life Strategies
by Francesco Borda, Rocco Adduci, Domenico Mundo and Francesco Gagliardi
J. Manuf. Mater. Process. 2025, 9(1), 14; https://doi.org/10.3390/jmmp9010014 - 6 Jan 2025
Cited by 1 | Viewed by 1341
Abstract
Gears remain a fundamental component in mechanical power transmission, with ongoing research focused on enhancing performance and sustainability. This study addresses the process of gear lightweighting, a key factor for efficiency improvements in automotive and aerospace sectors. Traditionally, material removal from gear bodies [...] Read more.
Gears remain a fundamental component in mechanical power transmission, with ongoing research focused on enhancing performance and sustainability. This study addresses the process of gear lightweighting, a key factor for efficiency improvements in automotive and aerospace sectors. Traditionally, material removal from gear bodies results in weight reduction, but at the cost of increased noise and vibration. A novel approach using hybrid gears, which combine a metal rim and hub with a composite material web, offers a promising solution. This research proposes a comparative environmental analysis among a conventional full steel, a lightweight and a hybrid gear using a life cycle energy quantification. The study considers two End-of-Life (EoL) scenarios: a conventional open loop scenario with partial recycling and a closed loop scenario with comprehensive recycling, including a thermal recycling for carbon fiber-reinforced plastics. The Cumulative Energy Demand (CED) has been conducted by applying a cradle-to-grave approach. The CED has been evaluated for each gear configuration quantifying the impact of each unit process involved in the production of the gear, from raw material extraction to product manufacturing and from use phase to different EoL scenarios. The cumulative results, performed preserving the same mechanical performance, indicate that the CED of the hybrid gear in the conventional open loop scenario is comparable to the one of the full gears, with an increase of 12.58%. In contrast, in the closed loop scenario, the hybrid gear exhibits substantial energy recovery benefits, with an overall CED difference of 7.50% compared to the lightweight gear and of 28.82% compared to the full gear. These results underline the potential of hybrid gears to improve efficiency, being able to achieve a 20% weight reduction with respect to the full gears, and to reduce environmental impact if effective recycling strategies were implemented. Full article
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