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Articoli di riviste sul tema "Solvant durable"

Autore: Grafiati

Pubblicato: 5 ottobre 2024

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1

Wu, Yunxuan, Jie Li, Yangfu Jin e Mi Zhou. "Binary solvent systems for durable self-adhesive conductive hydrogels". Journal of Polymer Engineering 40, n. 3 (25 febbraio 2020): 221–30. http://dx.doi.org/10.1515/polyeng-2019-0304.

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AbstractConductive hydrogels without adhesiveness and durability characteristics face great challenges in practical applications, such as inconvenient use, unstable contact voltage, and difficult to store. Herein, we present sodium polyacrylate (PAANa) hydrogels with binary solvent systems composed of water and an alcohol [ethylene glycol (EG), glycerol (GLY), or poly(ethylene glycol) (PEG)] as solvent instead of traditional water to research their self-adhesiveness, durability, conductivity, and mechanical properties. PAANa hydrogels exhibited higher self-adhesive properties and durability after alcohol content increased, and GLY/water hydrogels showed the best self-adhesive and stable properties. With more alcohols added, the weaker conductivity became, and EG/water hydrogels showed the highest conductivity. It was observed the long carbon chain length of alcohol could help improve the rheological properties of hydrogels. Thus, PEG/water hydrogels had the highest storage modulus, loss modulus, and consistency. The results demonstrated that the GLY/water binary solvent could provide good self-adhesiveness and durability, but EG/water and PEG/water showed better conductivity and mechanical properties, respectively. Therefore, our work may provide novel physical insights into the long-term usage of self-adhesive conductive hydrogels to practical requirements.

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Sreekantan, Srimala, Ang Xue Yong, Norfatehah Basiron, Fauziah Ahmad e Fatimah De’nan. "Effect of Solvent on Superhydrophobicity Behavior of Tiles Coated with Epoxy/PDMS/SS". Polymers 14, n. 12 (14 giugno 2022): 2406. http://dx.doi.org/10.3390/polym14122406.

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Superhydrophobic coatings are widely applied in various applications due to their water-repelling characteristics. However, producing a durable superhydrophobic coating with less harmful low surface materials and solvents remains a challenge. Therefore, the aim of this work is to study the effects of three different solvents in preparing a durable and less toxic superhydrophobic coating containing polydimethylsiloxane (PDMS), silica solution (SS), and epoxy resin (DGEBA). A simple sol-gel method was used to prepare a superhydrophobic coating, and a spray-coating technique was employed to apply the superhydrophobic coating on tile substrates. The coated tile substrates were characterized for water contact angle (WCA) and tilting angle (TA) measurements, Field-Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). Among 3 types of solvent (acetone, hexane, and isopropanol), a tile sample coated with isopropanol-added solution acquires the highest water contact angle of 152 ± 2° with a tilting angle of 7 ± 2° and a surface roughness of 21.80 nm after UV curing for 24 h. The peel off test showed very good adherence of the isopropanol-added solution coating on tiles. A mechanism for reactions that occur in the best optimized solvent is proposed.

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Brown, Philip S., e Bharat Bhushan. "Durable superoleophobic polypropylene surfaces". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, n. 2073 (6 agosto 2016): 20160193. http://dx.doi.org/10.1098/rsta.2016.0193.

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Polypropylene (PP) is a popular plastic material used in consumer packaging. It would be desirable if such plastic containers were liquid repellent and not so easily fouled by their contents. Existing examples of superoleophobic surfaces typically rely on poorly adhered coatings or delicate surface structures, resulting in poor mechanical durability. Here, we report a facile method for creating superoleophobic PP surfaces via incorporation of nanoparticles (NPs) into the polymer surface. A solvent–NP–PP mixture was spin coated at high temperature to achieve the necessary roughness. Such surfaces were further functionalized with fluorosilane to result in a durable, super-repellent surface. They were also found to exhibit some repellency towards shampoos. This method of incorporating NPs into polymer surfaces could also prove useful in improving the anti-bacterial, mechanical and liquid-repellent properties of plastic devices. This article is part of the themed issue ‘Bioinspired hierarchically structured surfaces for green science’.

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4

Poggiali, Lisa. "Solving Refugees' Problems or Solving the Problem of Refugees?" Politikon: The IAPSS Journal of Political Science 10 (1 novembre 2005): 51–61. http://dx.doi.org/10.22151/politikon.10.4.

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In the following paper I argue that in our contemporary global political climate - which is characterized by gross power differentials between the global North and South - the "international humanitarian regime" conceptualizes refugees as a "problem" to be "solved". It is through this conceptualization that repatriation has become the preferred "durable solution" to refugees' plight. Rather than solving refugees' problems, however, I contend that repatriation today serves to solve the problem of refugees. As such, I argue that repatriation is not only far from a durable solution, but far from a solution at all. I suggest that if we wish to truly help refugees find durable solutions to their problems we must first interrogate the unequal global power dynamics that produce refugee situations.

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5

Pan, Shuaijun, Rui Guo e Weijian Xu. "Durable superoleophobic fabric surfaces with counterintuitive superwettability for polar solvents". AIChE Journal 60, n. 8 (18 giugno 2014): 2752–56. http://dx.doi.org/10.1002/aic.14517.

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6

Lu, Tian-Dan, Liu-Lin Zhao, Wai Fen Yong, Qian Wang, Lei Duan e Shi-Peng Sun. "Highly solvent-durable thin-film molecular sieve membranes with insoluble polyimide nanofibrous substrate". Chemical Engineering Journal 409 (aprile 2021): 128206. http://dx.doi.org/10.1016/j.cej.2020.128206.

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7

De Sloovere, Dries, Danny E. P. Vanpoucke, Andreas Paulus, Bjorn Joos, Lavinia Calvi, Thomas Vranken, Gunter Reekmans et al. "Deep Eutectic Solvents as Nonflammable Electrolytes for Durable Sodium‐Ion Batteries". Advanced Energy and Sustainability Research 3, n. 3 (12 gennaio 2022): 2100159. http://dx.doi.org/10.1002/aesr.202100159.

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8

De Sloovere, Dries, Danny E. P. Vanpoucke, Andreas Paulus, Bjorn Joos, Lavinia Calvi, Thomas Vranken, Gunter Reekmans et al. "Deep Eutectic Solvents as Nonflammable Electrolytes for Durable Sodium‐Ion Batteries". Advanced Energy and Sustainability Research 3, n. 3 (marzo 2022): 2270007. http://dx.doi.org/10.1002/aesr.202270007.

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9

Šutka, Andris, Linda Mežule, Viktorija Denisova, Jochen Meier-Haack, Akshay Kulkarni, Sanda Bitina, Krisjanis Smits e Svetlana Vihodceva. "Straightforward Approach for Preparing Durable Antibacterial ZnO Nanoparticle Coatings on Flexible Substrates". Molecules 27, n. 22 (8 novembre 2022): 7672. http://dx.doi.org/10.3390/molecules27227672.

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Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer substrates at room temperature. Substrates used are polystyrene, poly(ethylene-co-vinyl acetate) copolymer, poly(methyl methacrylate), polypropylene, high density polyethylene and a commercial acrylate type adhesive tape. The deposition was achieved by a spin-coating process using a slurry of ZnO nanoparticles in toluene. A stable modification layer was obtained when toluene was a solvent for the polymer substrates, namely polystyrene and poly(ethylene-co-vinyl acetate). These coatings show high antibacterial efficiency causing >5 log decrease in the viable counts of Gram-negative bacteria Escherichia. coli and Gram-positive bacteria Staphylococcus aureus in 120 min. Even after tapping these coated surfaces 500 times, the antibacterial properties remained unchanged, showing that the coating obtained by the presented method is very robust. In contrast to the above findings, the coatings are unstable when toluene is not a solvent for the substrate.

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10

Yang, Guang, Michelle Lehmann, Ethan Self e Tomonori Saito. "(Invited) Innovating Sustainable, Cost-Effective, and Durable Redox Flow Battery Membranes". ECS Meeting Abstracts MA2024-01, n. 3 (9 agosto 2024): 527. http://dx.doi.org/10.1149/ma2024-013527mtgabs.

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In the quest to integrate renewable energy sources like solar and wind into the electric grid efficiently, the development of long-duration energy storage (LDES) systems is paramount. The U.S. Department of Energy's Long Duration Storage Shot initiative is at the forefront of this endeavor, aiming to reduce the costs of grid-scale energy storage by 90% for systems with over 10 hours of operation. A key player in this mission is the non-aqueous redox flow battery (RFB), known for its use of earth-abundant materials and potential to meet these cost-reduction goals. However, the commercial viability of RFBs hinges on the development of high-performance, cost-effective membranes, which are crucial for their functionality and affordability. These membranes' ionic conductivity is vital for the power density of RFBs, while their ion selectivity and solvent uptake greatly influence the batteries' cycle life. Our team has made groundbreaking advancements in membrane technology for non-aqueous flow batteries. We've addressed the challenge of balancing ionic conductivity with mechanical strength in polymer electrolytes. Our findings reveal that enhanced solvent uptake while boosting membrane ionic conductivity, can compromise mechanical integrity. To counter this, we've employed two strategies: selective plasticization of the ion-conductive block in block copolymers and reinforcing the membrane's mechanical strength through hydrogen and ionic bonds with an inorganic scaffold. Significantly, we've also reduced the crossover of redox-active species in our membrane designs, notably decreasing polysulfide species crossover in a Na metal – polysulfide hybrid flow battery. This has led to improved capacity retention, Coulombic efficiency, and extended cycle life compared to traditional porous membranes. Our latest innovations include the development of hydrocarbon single-ion conductors, demonstrating enhanced conductivity and stability. We've also introduced crosslinking chemistry to control solvent uptake more effectively, thus improving ionic conductivity while preserving mechanical strength. Lastly, our pioneering tape casting method for producing ceramic-polymer composite membranes represents a major leap in scalable membrane production, paving the way for the practical application of non-aqueous redox flow batteries in long-duration energy storage. Acknowledgment This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is sponsored by the U.S. Department of Energy through the Energy Storage Program in the Office of Electricity. We acknowledge Dr. Jagjit Nanda SLAC National Accelerator Laboratory for the fruitful discussions.

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Zhang, Xiaojuan, Xiaomeng Chu, Min Zhang, Meng Zhu, Yingda Huang, Yiguang Wang, Lei Liu e Nanwen Li. "Molecularly designed, solvent processable tetraalkylammonium-functionalized fluoropolyolefin for durable anion exchange membrane fuel cells". Journal of Membrane Science 574 (marzo 2019): 212–21. http://dx.doi.org/10.1016/j.memsci.2018.12.082.

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Gao, Yun Jing, Lin Lin Zhou e Hui Huang Pi. "Research on Durable Consumer Goods Manufacturer's Pricing Decision". Applied Mechanics and Materials 687-691 (novembre 2014): 4823–27. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.4823.

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The pricing decision of consumer goods manufacturing enterprise is a very important part in its business strategies. Price of the product is directly related to the ability to obtain the expected earnings. In this paper, based on the analysis of the characteristics of durable consumer goods and the factors that affect the price, considering the continuous product innovation and diversification of consumer demand, psychological factors of consumers, as well as the price timeliness, starting from the quantitative point of view, a dynamic pricing model of durable consumer goods aimed at the maximum value of products was set up. Finally, a numerical example solving by the genetic algorithm was given to verify the feasibility of the model.

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De Smet, David, Madeleine Wéry, Willem Uyttendaele e Myriam Vanneste. "Bio-Based Waterborne PU for Durable Textile Coatings". Polymers 13, n. 23 (2 dicembre 2021): 4229. http://dx.doi.org/10.3390/polym13234229.

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Polyurethane (PU) coatings are often applied on high added value technical textiles. Key factor to success of PU coatings is its versatility and durability. Up to today most PU textile coatings are solvent-based or water-based. Recent advances are made in applying bio-based PU on textiles. Currently, polymers made from renewable raw materials are experiencing a renaissance, owing to the trend to reduce CO2 emissions, the switch to CO2-neutral renewable products and the depletion of fossil resources. However, the application of bio-based coatings on textiles is limited. The present paper discusses the potential of a bio-based anionic PU dispersion as an environment friendly alternative for petroleum-based PU in textile coating. Coatings were applied on textile via knife over roll. The chemical, thermal and mechanical properties of the bio-based PU coating were characterised via FT-IR, thermogravimetric analysis, differential scanning calorimetry and tensile test. The performance of the coating was studied by evaluating antimicrobial properties, fire retardancy, the resistance to hydrostatic pressure initially and after washing, QUV ageing and hydrolysis test. The developed bio-based PUD coating complied to the fire retardancy test ISO 15025 and exhibited excellent hydrostatic pressure, QUV ageing resistance, hydrolysis resistance, wash fastness at 40 °C.

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Si, Hanmo, Qingwang Liu, Zhenzhong Fan, Biao Wang, Qilei Tong e Mengqi Lin. "A Durable Magnetic Superhydrophobic Melamine Sponge: For Solving Complex Marine Oil Spills". Nanomaterials 12, n. 14 (20 luglio 2022): 2488. http://dx.doi.org/10.3390/nano12142488.

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The problem of offshore oil leakage has wreaked havoc on the environment and people’s health. A simple and environmentally friendly impregnation method combined with marine mussel bionics was used to address this issue. Using the viscosity of polydopamine (PDA), nano- Fe3O4 and WS2 adhered to the framework of the melamine sponge (MS), and then the magnetic sponge was modified with n-octadecanethiol (OTD), and finally the superhydrophobic magnetic melamine sponge (mMS) was prepared. The modified sponge has superhydrophobicity (WCA, 156.8° ± 1.18°), high adsorbability (40~100 g°g−1), recyclability (oil adsorbability remains essentially unchanged after 25 cycles), efficient oil–water separation performance (>98%), and can quickly separate oil on the water’s surface and underwater. Furthermore, the modified sponge exhibits excellent stability and durability under harsh operating conditions such as strong sunlight, strong acid, strong alkali, and high salt, and can control the direction of the sponge’s movement by loading a magnetic field. To summarize, mMS has many potential applications as a new magnetic adsorption material for dealing with complex offshore oil spill events.

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Sidhik, Siraj, Yafei Wang, Michael De Siena, Reza Asadpour, Andrew J. Torma, Tanguy Terlier, Kevin Ho et al. "Deterministic fabrication of 3D/2D perovskite bilayer stacks for durable and efficient solar cells". Science 377, n. 6613 (23 settembre 2022): 1425–30. http://dx.doi.org/10.1126/science.abq7652.

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Realizing solution-processed heterostructures is a long-enduring challenge in halide perovskites because of solvent incompatibilities that disrupt the underlying layer. By leveraging the solvent dielectric constant and Gutmann donor number, we could grow phase-pure two-dimensional (2D) halide perovskite stacks of the desired composition, thickness, and bandgap onto 3D perovskites without dissolving the underlying substrate. Characterization reveals a 3D–2D transition region of 20 nanometers mainly determined by the roughness of the bottom 3D layer. Thickness dependence of the 2D perovskite layer reveals the anticipated trends for n-i-p and p-i-n architectures, which is consistent with band alignment and carrier transport limits for 2D perovskites. We measured a photovoltaic efficiency of 24.5%, with exceptional stability of T 99 (time required to preserve 99% of initial photovoltaic efficiency) of >2000 hours, implying that the 3D/2D bilayer inherits the intrinsic durability of 2D perovskite without compromising efficiency.

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Kang, Young Hun, Eun Jin Bae, Min‐Hye Lee, Mijeong Han, Bumjoon J. Kim e Song Yun Cho. "Highly Flexible and Durable Thermoelectric Power Generator Using CNT/PDMS Foam by Rapid Solvent Evaporation". Small 18, n. 5 (4 gennaio 2022): 2106108. http://dx.doi.org/10.1002/smll.202106108.

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Uzun, Kubra, Ming Wang, Xiaosong Huang, Bradley Frieberg, Jiazhi Hu e Yang-Tse Cheng. "Understanding the Effects of the Mixing Processes on the Performance of NMC-LMO Blend Electrodes Made By a Dry Electrostatic Spray Deposition Process". ECS Meeting Abstracts MA2022-02, n. 7 (9 ottobre 2022): 2551. http://dx.doi.org/10.1149/ma2022-0272551mtgabs.

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Improving the manufacturing process of making lithium-ion batteries (LIBs) is a key to further decreasing the cost and expanding the market of LIBs for many applications, especially for electric vehicles. Since electric vehicles require durable, sustainable, and cost-effective battery systems for their continued enlargement, advanced manufacturing processes of LIBs need to be investigated. The conventional wet slurry operation for LIB electrode manufacturing imposes several limitations on cost and performance mostly due to solvent usage. The drying process for the evaporation and recovery of organic solvent requires the use of unwanted solvents that do not contribute to the final product, thus consuming energy. If solvent evaporation is not controlled well, issues such as binder migration, segregation, and cracking of the electrode can occur, affecting the performance of the battery. Therefore, using a solventless dry process for electrode manufacturing has the potential to reduce the cost and environmental impact by eliminating solvent usage. In this work, electrostatic spray deposition (ESD) without the use of a solvent is investigated for manufacturing thick NMC811/LMO electrodes. Comparing two different dry powder mixing methods, we showed that dry powder mixing prior to ESD has a significant effect on the electrode microstructure and, consequently, its performance. Electrodes made by ball mill mixing retained better discharge capacity, which was attributed to the low charge transfer resistance and improved ionic conductivity due to porous conductive pathways formed between and on the active material particles. High speed mixing, on the other hand, caused dense layers of binder and conductive agent agglomerates, limiting the contact area of the electrolyte with active materials and increasing the resistance.

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Li, Yongsheng, Meng Ren, Pengfei Lv, Yinzhi Liu, Hong Shao, Cong Wang, Changyu Tang, Yuanlin Zhou e Maobing Shuai. "A robust and flexible bulk superhydrophobic material from silicone rubber/silica gel prepared by thiol–ene photopolymerization". Journal of Materials Chemistry A 7, n. 12 (2019): 7242–55. http://dx.doi.org/10.1039/c8ta11111a.

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Giribabu, L., C. Vijay Kumar, M. Raghavender, K. Somaiah, P. Yella Reddy e P. Venkateswara Rao. "Durable Unsymmetrical Zinc Phthalocyanine for Near IR Sensitization of Nanocrystalline TiO₂ Films with Non-Volatile Redox Electrolytes". Journal of Nano Research 2 (agosto 2008): 39–48. http://dx.doi.org/10.4028/www.scientific.net/jnanor.2.39.

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We are presenting our results based on unsymmetrical zinc phthalocyanine by adopting ‘push-pull’ concept for the nanocrystalline dye-sensitized solar cells. Using this sensitizer in combination with nonvolatile organic-solvent-based electrolytes, we obtained a photovoltaic efficiency of 1.52% under standard global AM 1.5 sunlight and compared the results with volatile organic-solvent based electrolyte. These devices exhibit admirable stability when subjected to continuous thermal stress at 60 oC for 1000 h. The sensitizer is thermally stable up to 150 oC and can be useful for roof top applications.

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Joshi, Shubham, Vinay Midha e Subbiyan Rajendran. "Investigation of Durable Bio-polymeric Antimicrobial Finishes to Chemically Modified Textile Fabrics Using Solvent Induction System". TEKSTILEC 64, n. 1 (14 gennaio 2021): 55–69. http://dx.doi.org/10.14502/tekstilec2021.64.55-69.

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New technologies and materials required for developing antibacterial textiles have become a subject of inter¬est to the researchers in recent years. This study focuses on the investigation of the biopolymeric antibacterial agents, such as neem, aloe vera, tulsi and grapeseed oil, in the trichloroacetic acid-methylene chloride (TCAMC) solvent used for the pretreatment of polyethylene terephthalate (PET) polyester fabrics. Different PET structures, such as 100% polyester, polyester/viscose, polyester/cotton and 100% texturised, are treated with four different concentrations (5%, 10%, 15% and 20%) of biopolymeric antibacterial finishes. The antibacterial activity of the treated samples is tested against both the Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. Taguchi mixed orthogonal array Design L16 (4^3 2^2) is chosen for an experimental plan to determine the optimum conditions. Among all the fabric samples, the 100% polyester fabric treated with 20% grapeseed oil registers the highest antibacterial activity of 86%, and 73% against S. aureus and E. coli respec¬tively. However, the antibacterial effect is reduced to 37%, and 34% respectively after 10 machine launderings.

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Hu, Guangwu, Kunzhe Zhong, Ruohan Yu, Zhenhui Liu, Yuanyuan Zhang, Jinsong Wu, Liang Zhou e Liqiang Mai. "Enveloping SiOx in N-doped carbon for durable lithium storage via an eco-friendly solvent-free approach". Journal of Materials Chemistry A 8, n. 26 (2020): 13285–91. http://dx.doi.org/10.1039/d0ta00540a.

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A solvent-free, flammable gas-free method is developed for the scalable synthesis of SiO_x@N-doped carbon (SiO_x@NC). The obtained SiO_x@NC manifests high specific capacity (774 mA h g⁻¹) with excellent durability in lithium storage.

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Madkour, Metwally, Khaled D. Khalil e Fakhreia A. Al-Sagheer. "Heterogeneous Hybrid Nanocomposite Based on Chitosan/Magnesia Hybrid Films: Ecofriendly and Recyclable Solid Catalysts for Organic Reactions". Polymers 13, n. 20 (17 ottobre 2021): 3583. http://dx.doi.org/10.3390/polym13203583.

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Chitosan/magnesia hybrid films (CS-Mg) have been prepared via sol-gel process and employed as heterogeneous catalysts. An in situ generation of a magnesia network in the chitosan matrix was performed through hydrolysis/condensation reactions of magnesium ethoxide. The synthesized hybrid films were characterized using various analytical techniques, such as X-ray photo-electron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The hybrid films display excellent catalytic activities in Michael and Knoevenagel reactions via one pot or solvent-free approaches under microwave irradiation conditions. Chitosan/magnesia hybrid films, catalysed pyrimidine, benzochromene, coumarin and arylidene-malononitriles derivatives formation reactions occurred with highly efficient yields of 97%, 92%, 86% and 95% respectively. Due to the fact that the films are durable and insoluble in common organic solvents, they were easily separated and can be recycled up to five times without a considerable loss of their catalytic activity.

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De Smet, David, Willem Uyttendaele e Myriam Vanneste. "Bio-Based 2K PU Coating for Durable Textile Applications". Coatings 12, n. 2 (28 gennaio 2022): 169. http://dx.doi.org/10.3390/coatings12020169.

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Polyurethane (PU) coatings are often applied on high added value technical textiles. To date, most PU textile coatings are solvent based or water based. Recent advances are made in applying high solid and two-component (2K) PU on textiles. Currently, polymers made from renewable raw materials are experiencing a renaissance, owing to the trend to reduce CO2 emissions and switch to CO2-neutral renewable products. There is also the tendency towards the “bio, eco, natural” consciousness-awakening of the end consumer and the market-driven question to implement renewable materials. However, the application of bio-based coatings on textiles is limited. In this regard, the present study is conducted to develop bio-based 2K PU coating specifically designed for waterproof textiles. A 2K PU coating formulation, composed of bio-based polyol and bio-based isocyanate Desmodur Eco N7300, was made and directly applied on a polyester fabric prior to thermal curing in an oven. The coating was characterized via Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The coatings were not thermoplastic and had a glass transition temperature of approximately 50 °C. Since a bio-based pentamethylene diisocyanate trimer (PDI-trimer), Desmodur Eco N7300 was used as an isocyanate source and not a diisocyanate derivative, and the resulting bio-based 2K coating was a thermoset instead of a thermoplastic. The effect of the additives and content of isocyanate on the elongation and stress at break was studied by performing tensile tests (ISO 13934-1) on 50 µm 2K PU films and comparing the obtained values. The performance of the coating was studied by evaluating the resistance to hydrostatic pressure initially and after washing, the Q-panel Laboratory UltraViolet (QUV) aging and the hydrolysis test. The developed bio-based 2K PU coating had excellent hydrostatic pressure, QUV aging resistance, hydrolysis resistance and wash fastness at 60 °C.

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Zhang, Jiayao, Shixiang Liu, Yajiang Huang, Yadong Lv, Miqiu Kong e Guangxian Li. "Durable fluorinated-SiO2/epoxy superhydrophobic coatings on polycarbonate with strong interfacial adhesion enhanced by solvent-induced crystallization". Progress in Organic Coatings 150 (gennaio 2021): 106002. http://dx.doi.org/10.1016/j.porgcoat.2020.106002.

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Baidya, Avijit, Mohd Azhardin Ganayee, Swathy Jakka Ravindran, Kam Chiu Tam, Sarit Kumar Das, Robin H. A. Ras e Thalappil Pradeep. "Organic Solvent-Free Fabrication of Durable and Multifunctional Superhydrophobic Paper from Waterborne Fluorinated Cellulose Nanofiber Building Blocks". ACS Nano 11, n. 11 (27 ottobre 2017): 11091–99. http://dx.doi.org/10.1021/acsnano.7b05170.

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Yu, Lejian, Chuangchuang Yang, Wendu Zhang, Weiqi Liu, Huifen Wang, Jiawei Qi e Lang Xu. "Solvent-free synthesis of N-doped nanoporous carbon materials as durable high-performance pH-universal ORR catalysts". Journal of Colloid and Interface Science 575 (settembre 2020): 406–15. http://dx.doi.org/10.1016/j.jcis.2020.05.012.

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Shen, Jialong, Yue Yuan e Sonja Salmon. "Durable and Versatile Immobilized Carbonic Anhydrase on Textile Structured Packing for CO2 Capture". Catalysts 12, n. 10 (25 settembre 2022): 1108. http://dx.doi.org/10.3390/catal12101108.

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High-performance carbon dioxide (CO2)-capture technologies with low environmental impact are necessary to combat the current climate change crisis. Durable and versatile “drop-in-ready” textile structured packings with covalently immobilized carbonic anhydrase (CA) were created as efficient, easy to handle catalysts for CO2 absorption in benign solvents. The hydrophilic textile structure itself contributed high surface area and superior liquid transport properties to promote gas-liquid reactions that were further enhanced by the presence of CA, leading to excellent CO2 absorption efficiencies in lab-scale tests. Mechanistic investigations revealed that CO2 capture efficiency depended primarily on immobilized enzymes at or near the surface, whereas polymer entrapped enzymes were more protected from external stressors than those exposed at the surface, providing strategies to optimize performance and durability. Textile packing with covalently attached enzyme aggregates retained 100% of the initial 66.7% CO2 capture efficiency over 71-day longevity testing and retained 85% of the initial capture efficiency after 1-year of ambient dry storage. Subsequent stable performance in a 500 h continuous liquid flow scrubber test emphasized the material robustness. Biocatalytic textile packings performed well with different desirable solvents and across wide CO2 concentration ranges that are critical for CO2 capture from coal and natural gas-fired power plants, from natural gas and biogas for fuel upgrading, and directly from air.

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Zheng, Xunwen, Ling Miao, Ziyang Song, Wenyan Du, Dazhang Zhu, Yaokang Lv, Liangchun Li, Lihua Gan e Mingxian Liu. "In situ nanoarchitecturing of conjugated polyamide network-derived carbon cathodes toward high energy-power Zn-ion capacitors". Journal of Materials Chemistry A 10, n. 2 (2022): 611–21. http://dx.doi.org/10.1039/d1ta07350h.

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Abstract (sommario):

The solvent-guided shaping of conjugated polymides activates O/N Zn-storage sites on the robust carbon architecture, which facilitates reversible Zn electrosorption and durable charge tansfer toward high energy-power Zn-ion capacitors.

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29

Vo, Truong-Giang, Sebastian Dario Suarez Hidalgo e Chia-Ying Chiang. "Controllable electrodeposition of binary metal films from deep eutectic solvent as an efficient and durable catalyst for the oxygen evolution reaction". Dalton Transactions 48, n. 39 (2019): 14748–57. http://dx.doi.org/10.1039/c9dt03028j.

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30

Zhang, Na, Lei Du, Chunyu Du e Geping Yin. "Tin dioxide facilitated truncated octahedral Pt3Ni alloy catalyst: synthesis and ultra highly active and durable electrocatalysts for oxygen reduction reaction". RSC Advances 6, n. 31 (2016): 26323–28. http://dx.doi.org/10.1039/c6ra02452a.

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Abstract (sommario):

This work firstly synthesized SnO₂ modified truncated octahedral Pt₃Ni alloy nanoparticle electrocatalyst using neat FPD as the solvent, ORR activity and durability of which is 2.4 times and 2.5 times that of Pt₃Ni catalysts.

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31

Matthews, Guillaume, Benjamin Meyer e Patrick Grant. "Understanding the Role of the Binder on the Microstructure and Properties of PTFE-Based Solvent-Free Electrodes". ECS Meeting Abstracts MA2023-02, n. 6 (22 dicembre 2023): 928. http://dx.doi.org/10.1149/ma2023-026928mtgabs.

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Abstract (sommario):

Solvent-free processing, also known as dry-processing refers to a group of manufacturing methods which avoid the use of solvents in the production of electrodes for energy storage applications. This concept has been around for more than a decade, although its popularity has increased dramatically over the last couple of years after the purchase of Maxwell technologies by Tesla. Maxwell patented a novel processing route which involves dry mixing the active material powder with a PTFE binder to form an electrode without the use of any solvent. Solvent-free processes have significant advantages in terms of sustainability, safety and cost over conventional slurry casting. A detailed analysis of the slurry casting process showed that around a quarter of the total manufacturing cost of the battery pack originated from solvent associated steps. Avoiding the use of toxic and flammable solvents such as N-methyl Pyrrolidone (NMP) also naturally leads to an improvement in the safety of the manufacturing environment. More importantly, it was reported that the manufacturing steps associated with solvent removal accounted for half of the embodied energy of a typical Li-ion battery. The embodied energy of a Li-ion battery is a crucial figure of merit in terms of sustainability which is too often neglected. To put things into perspective, Volvo has recently published a carbon footprint report for their fully electric Volvo C40 Recharge and compared it to their internal combustion engine (ICE) equivalent, the XC40. They reported that the production of the electric version generated 26 tonnes of CO2-equivalents compared to 16 tonnes for the ICE model, representing a large increase of almost 70% in the embodied energy of the car. Novel and more sustainable manufacturing processes are urgently needed to reduce as much as possible the embodied energy of Li-ion batteries and make them more sustainable to enable a durable green energy transition. Although the concept of solvent-free processing seems attractive, most of its current development is happening behind closed doors in industry. However, an in-depth characterisation of this new type of electrodes and a comparison with conventional slurry cast electrodes would be beneficial to understand the challenges and opportunities brought by these new systems and help accelerate their development on a larger scale. Within the family of solvent-free processes, three main techniques have emerged: dry painting, powder injection molding and PTFE-fibrillation. Studies dedicated to electrodes based on PTFE-fibrillation are rare and often focused on solid-state systems. In order to dispel some of the mystery surrounding the novel microstructures obtained through the PTFE-fibrillation process and their performance, this work focuses on the characterisation of these new electrodes and investigate the role of the PTFE binder on the microstructure and electrochemical performance of solvent-free electrodes. Our results highlight the crucial importance of the PTFE binder on the mechanical properties of the solvent-free electrodes and reveal how the peculiar mechanical behavior of these composite electrodes during the manufacturing process influences the final microstructure of the electrodes and their electrochemical performance. This work presents a deep insight into PTFE-based solvent-free electrodes by investigating their microstructure, mechanical and electrochemical properties using advanced characterization techniques including High Resolution Analytical Scanning Electron Microscopy, X-Ray Computed Tomography, Electrochemical Impedance Spectroscopy and mechanical testing.

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32

SINGH, NAGENDER, SAMINATHAN RATNAPANDIAN e JAVED SHEIKH. "DURABLE MULTIFUNCTIONAL FINISHING OF COTTON USING -CYCLODEXTRIN-GRAFTED CHITOSAN AND LEMONGRASS(CYMBOPOGON CITRATUS) OIL". Cellulose Chemistry and Technology 55, n. 1-2 (12 febbraio 2021): 177–84. http://dx.doi.org/10.35812/10.35812/cellulosechemtechnol.2021.55.19.

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Abstract (sommario):

Multifunctional finishing of textiles enhances the value of products by adding desired biological and functional properties. The purpose of this study was to extract essential oil from lemongrass and apply the extracted oil to traditional cotton fabric as finishing. Lemongrass oleoresin was obtained by extracting fresh blades of lemongrass for 16 h using a Soxhlet extractor, employing n-hexane as solvent, by the AATCC Method 30-25. The pad-dry technique was applied to impart fragrance to cotton fabric by using a finishing formulation containing lemongrass oil and β-cyclodextrin-grafted chitosan. The ester bond formation between β-cyclodextrin-grafted chitosan and cellulose was confirmed by FTIR spectroscopy (FTIR). After finishing, the fragrance release rate was evaluated by UV-visible spectroscopy. The fragrance release rate of the finished fabric was found to be durable up to 18 washing cycles and the fabric presented excellent antibacterial property and antioxidant activity. Standard test methods were used to evaluate the physical properties of the treated fabric.

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33

Hu, Guangwu, Aoyuan Chen, Ruohan Yu, Kunzhe Zhong, Yuanyuan Zhang, Jinsong Wu, Liang Zhou e Liqiang Mai. "Solvent-Free Encapsulation of Ultrafine SnO2 Nanoparticles in N-Doped Carbon for High-Capacity and Durable Lithium Storage". ACS Applied Energy Materials 4, n. 6 (27 maggio 2021): 6277–83. http://dx.doi.org/10.1021/acsaem.1c01056.

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34

Kang, Young Hun, Eun Jin Bae, Min‐Hye Lee, Mijeong Han, Bumjoon J. Kim e Song Yun Cho. "Highly Flexible and Durable Thermoelectric Power Generator Using CNT/PDMS Foam by Rapid Solvent Evaporation (Small 5/2022)". Small 18, n. 5 (febbraio 2022): 2270020. http://dx.doi.org/10.1002/smll.202270020.

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35

Zhang, Fengxiu, Weiwei Gao, Yaling Jia, Yi Lu e Guangxian Zhang. "A concise water-solvent synthesis of highly effective, durable, and eco-friendly flame-retardant coating on cotton fabrics". Carbohydrate Polymers 199 (novembre 2018): 256–65. http://dx.doi.org/10.1016/j.carbpol.2018.05.085.

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36

Zhang, Jiahui, Xiaowei Guo, Xiaomeng Zhang, Huimin Wang, Jiufu Zhu, Zuosen Shi, Song Zhu e Zhanchen Cui. "Hydrolysis-resistant and stress-buffering bifunctional polyurethane adhesive for durable dental composite restoration". Royal Society Open Science 7, n. 7 (luglio 2020): 200457. http://dx.doi.org/10.1098/rsos.200457.

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Abstract (sommario):

A new elastic polyurethane (PU) adhesive was reported in this study to improve the stability and durability of the dental adhesion interface. A polyurethane oligomer was synthesized by the solution polymerization method, and a diluent and solvent were added to prepare PU adhesives. The water sorption, water solubility, contact angle, thermal stability, degree of conversion and mechanical properties of the PU adhesives were evaluated. Experimental applications for tooth restoration (microtensile bond strength and microleakage) were also performed, and cytotoxicity test was carried out. The water sorption and solubility of the PU adhesives were significantly lower than those of three commercial adhesives. The microtensile bond strength of the PU adhesives was improved after thermocycling test, and the extent of microleakage was diminished when compared with that of commercial adhesives. Biocompatibility testing demonstrated that the PU adhesive was non-toxic to L929 fibroblasts. This study shows the ability of PU adhesive to improve the stability and durability of the dental adhesion interface and may refocus the attention of scientists from rigid bonding to flexible bonding for dental adhesion, and it sheds light on a new strategy for the stable and durable bonding interface of dentine adhesives.

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37

Baucal, Aleksandar. "Construction and co-construction in the zone of proximal development: Could both Piaget and Vygotsky be right?" Psihologija 36, n. 4 (2003): 517–42. http://dx.doi.org/10.2298/psi0304517b.

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Abstract (sommario):

The main goal of the research is to get evidence to address the following issues: (1) What is the relationship between the Zone of Actual Development (ZAD) and the Zone of Proximal Development (ZPD)?, (2) Is the effect of the tasks joint solving relatively durable?, (3) Does the ZPD have predictive values for the future achievement over and above of ZAD?, and (4) What is more important for the prediction of future achievements - affective-motivational or cognitive help in joint solving? The experiment with parallel groups with 126 subjects is realised. Experimental treatment is consisted of solving of Raven matrices items with a gradual help given by experimenter according to previously defined plan. The results suggest: (1) there is positive and low correlation between ZAD and ZPD, (2) the effect of joint solving is relatively durable, (3) ZPD is significant predictor of future achievements over and above of ZAD, and (4) affective-motivational aspect of joint activity has stronger influence on future achievements than cognitive one.

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38

He, Jian, Monia Runge Nielsen, Thomas Willum Hansen, Song Yang e Anders Riisager. "Hierarchically constructed NiO with improved performance for catalytic transfer hydrogenation of biomass-derived aldehydes". Catalysis Science & Technology 9, n. 5 (2019): 1289–300. http://dx.doi.org/10.1039/c8cy02536c.

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Abstract (sommario):

A 3D nanometer-scaled NiO material with urchin-like structure was prepared via a facile route, and served as a highly efficient and durable catalyst for catalytic transfer hydrogenation of bio-based furfural to furfuryl alcohol using 2-propanol as H-donor and solvent.

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39

Abraham, Jiji, Mohammed Arif P., Lekshmi Kailas, Nandakumar Kalarikkal, Soney C. George e Sabu Thomas. "Developing highly conducting and mechanically durable styrene butadiene rubber composites with tailored microstructural properties by a green approach using ionic liquid modified MWCNTs". RSC Advances 6, n. 39 (2016): 32493–504. http://dx.doi.org/10.1039/c6ra01886f.

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Abstract (sommario):

Present paper is focussed on the fabrication of styrene-butadiene rubber–ionic liquid modified CNT nano composites by using a more sustainable chemistry and a clean process with the use of a green solvent ionic liquid.

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40

Li, Fuyun, Le Yu, Qiaomei Hu, Songtao Guo, Yueni Mei, Qing Liu, Yapeng He e Xianluo Hu. "Fabricating low-temperature-tolerant and durable Zn-ion capacitors via modulation of co-solvent molecular interaction and cation solvation". Science China Materials 64, n. 7 (28 gennaio 2021): 1609–20. http://dx.doi.org/10.1007/s40843-020-1570-5.

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41

Liu, Shanqiu, Xiaotian Zhang e Stefan Seeger. "Solvent-Free Fabrication of Flexible and Robust Superhydrophobic Composite Films with Hierarchical Micro/Nanostructures and Durable Self-Cleaning Functionality". ACS Applied Materials & Interfaces 11, n. 47 (21 ottobre 2019): 44691–99. http://dx.doi.org/10.1021/acsami.9b15318.

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42

Li, Yanjie, e Clemens Altaner. "Calibration of near infrared spectroscopy (NIRS) data of three Eucalyptus species with extractive contents determined by ASE extraction for rapid identification of species and high extractive contents". Holzforschung 73, n. 6 (26 giugno 2019): 537–45. http://dx.doi.org/10.1515/hf-2018-0166.

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Abstract (sommario):

Abstract Plantations of naturally durable timber species could substitute unsustainably harvested wood from tropical forests or wood treated with toxic preservatives. The New Zealand Dryland Forests Initiative (NZDFI) has established a tree-breeding program to develop genetically improved planting stock for durable eucalyptus plantations. In this study the durable heartwood of Eucalyptus bosistoana, Eucalyptus globoidea and Eucalyptus argophloia was characterized by near infrared (NIR) spectroscopy and NIR data was calibrated with the extractives content (EC), determined by accelerated solvent extraction (ASE) extraction, by means of a partial least squares regression (PLSR) model. It was possible to predict the EC content in the range of 0.34–18.9% with a residual mean square error (RMSE) of 0.9%. Moreover, the three species could also be differentiated by NIR spectroscopy with 100% accuracy, i.e. NIR spectroscopy is able to segregate timbers from mixed species forest plantations.

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43

Caratenuto, Andrew, Sunny Leung, Nathaniel LeCompte e Yi Zheng. "Size-Dispersed Calcium Phosphate-Based Paints for Sustainable, Durable Cool Roof Applications". Energies 17, n. 16 (22 agosto 2024): 4178. http://dx.doi.org/10.3390/en17164178.

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Abstract (sommario):

Passive radiative cooling materials are widely recognized as attractive innovations for reducing emissions and expanding life-saving cooling access. Despite immense research attention, the adoption of such technologies is limited largely due to a lack of scalability and cost compatibility with market needs. While paint and coating-based approaches offer a more sensible solution, many demonstrations suffer from issues such as a low solar reflectance performance or a lack of material sustainability due to the use of harmful solvents. In this work, we demonstrate a passive radiative cooling paint which achieves an extremely high solar reflectance value of 98% using a completely water-based formulation. Material sustainability is promoted by incorporating size-dispersed calcium phosphate biomaterials, which offer broadband solar reflectance, as well as a self-crosslinking water-based binder, providing water resistance and durability without introducing harmful materials. Common industry pigments are integrated within the binder for comparison, illustrating the benefit of finely-tuned particle size distributions for broadband solar reflectance, even in low-refractive-index materials such as calcium phosphates. With scalability, outdoor durability, and eco-friendly materials, this demonstrated paint offers a practical passive radiative cooling approach without exacerbating other environmental issues.

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44

Kim, Dongsu, Yeonghwan Jang, Eunho Choi, Ji Eon Chae e Segeun Jang. "Reinforced Nafion Membrane with Ultrathin MWCNTs/Ceria Layers for Durable Proton-Exchange Membrane Fuel Cells". Membranes 12, n. 11 (29 ottobre 2022): 1073. http://dx.doi.org/10.3390/membranes12111073.

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Abstract (sommario):

For further commercializing proton-exchange membrane fuel cells, it is crucial to attain long-term durability while achieving high performance. In this study, a strategy for modifying commercial Nafion membranes by introducing ultrathin multiwalled carbon nanotubes (MWCNTs)/CeO2 layers on both sides of the membrane was developed to construct a mechanically and chemically reinforced membrane electrode assembly. The dispersion properties of the MWCNTs were greatly improved through chemical modification with acid treatment, and the mixed solution of MWCNTs/CeO2 was uniformly prepared through a high-energy ball-milling process. By employing a spray-coating technique, the ultrathin MWCNTs/CeO2 layers were introduced onto the membrane surfaces without any agglomeration problem because the solvent rapidly evaporated during the layer-by-layer stacking process. These ultrathin and highly dispersed MWCNTs/CeO2 layers effectively reinforced the mechanical properties and chemical durability of the membrane while minimizing the performance drop despite their non-ion-conducting properties. The characteristics of the MWCNTs/CeO2 layers and the reinforced Nafion membrane were investigated using various in situ and ex situ measurement techniques; in addition, electrochemical measurements for fuel cells were conducted.

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45

Wang, Chih-Feng, Wen-Ning Wang, Ching-Hsuan Lin, Kuo-Jung Lee, Chien-Chieh Hu e Juin-Yih Lai. "Facile Fabrication of Durable Superhydrophobic Films from Carbon Nanotube/Main-Chain Type Polybenzoxazine Composites". Polymers 11, n. 7 (14 luglio 2019): 1183. http://dx.doi.org/10.3390/polym11071183.

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Abstract (sommario):

Superhydrophobic materials have immense applications in the fields of industry and research. However, their durability is still a cause for concern. A facile method for preparing durable superhydrophobic films from carbon nanotubes (CNTs) and the main-chain type polybenzoxazine precursors is reported herein. We used probe ultrasonicator to prepare CNT/polybenzoxazine coatings. Compared with the general sonicating dispersion process, the dispersion time was greatly reduced from a few hours to 5 minutes and the prepared suspension exhibited film-forming characteristics well. The CNT/polybenzoxazine films, which do not contain any fluorinated compounds, exhibit remarkable durability against thermal treatment, organic solvents, corrosive liquids, and sandpaper abrasion, while retaining their superhydrophobicity. Furthermore, these CNT/polybenzoxazine films also showed durable superhydrophobicity after ultraviolet (UV) irradiation for 100 h. This CNT/polybenzoxazine film can be readily used for practical applications to make durable superhydrophobic coatings.

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46

Zheng, Min, Xiangzhou Li, Youyi Xun, Jianhua Wang e Dulin Yin. "Selective Catalytic Epoxidation–Hydration of α-Pinene with Hydrogen Peroxide to Sobrerol by Durable Ammonium Phosphotungstate Immobilized on Imidazolized Activated Carbon". Nanomaterials 13, n. 9 (5 maggio 2023): 1554. http://dx.doi.org/10.3390/nano13091554.

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Abstract (sommario):

It is presented that the activated carbon was carboxylated with hydrogen peroxide and then acylated with 2-methylimidazole to prepare the porous carbon support with a surface imidazolated modification. Through the adsorption of phosphotungstic acid on the fundamental site of an imidazolyl group and then adjusting the acid strength with the ammonia molecule, a catalytic carbon material immobilized with ammonium phosphotungstate (AC-COIMO-NH4PW) was obtained, which was used to catalyze a one-pot reaction of convenient α-pinene and hydrogen peroxide to sobrerol. The bifunctional active site originated from the dual property of ammonium phosphotungstate, as the oxidant and acid presenting a cooperatively catalytic performance, which effectively catalyzes the tandem epoxidation–isomerization–hydration of α-pinene to sobrerol, in which the solvent effect of catalysis simultaneously exists. The sobrerol selectivity was significantly improved after the acid strength weakening by ammonia. Monomolecular chemical bonding and anchoring of ammonium phosphotungstate at the basic site prevented the loss of the active catalytic species, and the recovered catalyst showed excellent catalytic stability in reuse. Using acetonitrile as the solvent at 40℃ for 4 h, the conversion of α-pinene could reach 90.6%, and the selectivity of sobrerol was 40.5%. The results of five cycles show that the catalyst presents excellent stability due to the tight immobilization of ammonium phosphotungstate bonding on the imidazolized activated carbon, based on which a catalytic-cycle mechanism is proposed for the tandem reaction.

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47

Tang, Chongyang, Nan Zhang, Qi Shao, Xiaoqing Huang e Xiangheng Xiao. "Rational design of ordered Pd–Pb nanocubes as highly active, selective and durable catalysts for solvent-free benzyl alcohol oxidation". Nanoscale 11, n. 12 (2019): 5145–50. http://dx.doi.org/10.1039/c8nr07789d.

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Abstract (sommario):

Ordered Pd–Pb nanocubes (NCs) were adopted as efficient heterocatalysts for the selective benzyl alcohol oxidation. Due to the ordered phase and well-defined surface, the Pd–Pb NCs can achieve superior activity and selectivity, better than those of other catalysts as we prepared.

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48

Karki, Peshal, Morteza Sabet, Apparao M. Rao e Srikanth Pilla. "Carbon Encapsulated Silicon for High-Capacity Durable Anodes". ECS Meeting Abstracts MA2022-02, n. 4 (9 ottobre 2022): 499. http://dx.doi.org/10.1149/ma2022-024499mtgabs.

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Abstract (sommario):

One of the biggest challenges of the near future is how to meet the increasing energy demand without any adverse environmental impact. Lithium-Ion batteries (LIBs) are one of the promising alternative energy storage systems to replace conventional non-rechargeable batteries. LIBs are becoming one of the most widely used energy storage devices because of their relatively high specific energy density (~300 Wh/kg), excellent stability over a wide temperature range, and lower cost than other battery systems. Intense research is in progress to increase the capacity of anode electrodes for realizing high-energy LIBs. In this context, silicon (Si) has a great potential to replace commercial graphitic anode active materials mainly due to its high theoretical specific capacity (4200 mAh/g) and low working potential (0.37 to 0.45 V vs. Li/Li+). To harness and maintain a high capacity from Si-based anodes, we must deal with two main challenges: (i) volume changes of Si (>300%) during charging and discharging, which cause pulverization of the material and loss of electrical contact, and (ii) unstable growth of solid-electrolyte interphase (SEI) layer, which can cause early degradation of performance in Si-anode batteries. To overcome these challenges, different approaches have been taken. This includes developing graphite/Si anodes with limited amounts of Si (<30 wt.%), conformal coating of Si active materials (e.g., CVD carbon coating), etc. However, these challenges still could not be fully overcome. To advance the use of Si materials in LIB anodes, we developed a viable technology to create a hybrid silicon-carbon material, called Si@C, in which a soybean-derived carbon cloud protects Si nanoparticles during the battery operation. We employed soybean oil in a scalable oil-in-water emulsion polymerization technique to produce Si-containing polymeric particles. In this method, we emulsified two immiscible solutions. One contains a homogeneous Si mixture in epoxidized soybean oil (ESO), and another contains a uniform dispersion of ball-milled lignin or soyhull powders in water. Citric acid, a crosslinking agent, was used to help polymerize the ESO and integrate carbon-rich lignin/soyhull with polymerized particles. The final Si@C product was achieved by carbonizing the polymerized solid product at 500 °C (under argon) and ball milling to get a fine powder. Several Si@C hybrid materials containing 20 wt.% to 50 wt.% Si were successfully prepared and utilized for anode preparation. Electrodes were made by coating a slurry of Si@C active material, carbon black, and binder with a mass ratio of 60:20:20 onto an ion-permeable Bucky Paper (BP, a flexible and conductive paper made of carbon nanotubes). Anodes with different binding systems were prepared to determine an appropriate binder for Si@C based batteries. The 2032-type coin cells were assembled for battery testing using 1M LiPF6 in EC:DMC in a volume ratio of 1:1 as the electrolyte, Li chips as the counter electrode, and Celgard 2325 as the separator. The coin cells were cycled at a current rate of 0.1C (420 mA/gSi) over the potential range of 0.01 – 1.0 V at room temperature. Battery results showed that Si@C hybrid materials increased the capacity of Si anodes by a factor of >2. At Si mass loading of 1.0 mg/cm2, implementing our carbon cloud approach led to an increase in the discharge capacity of anodes from 0.5 mAh (corresponding to anode with bare Si) to >1.0 mAh (corresponding to anode with Si@C hybrids). Results from battery cycling at 0.1C demonstrated excellent capacity retention of >95% after 130 cycles for anodes prepared using our Si@C active materials. The Si content of Si@C hybrid particles was also found to be an influential factor in the cycling performance of anodes. Finally, we observed that the use of water-based polyacrylic acid (PAA) and carboxymethyl cellulose (CMC) binders improve the electrochemical performance of Si@C based anodes. These water-based binders are ideal for preparing Si-based slurries, and the need for using toxic solvents (e.g., NMP) to prepare slurries can be averted. In conclusion, we innovated a viable technology that uses biomass (soybean oil and soyhulls) to enhance Si-based batteries' performance. We demonstrated that our Si@C materials with a carbon cloud protecting the Si nanoparticles are promising active materials to improve the capacity and cycling stability of LIB anodes.

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49

Mustafa, Ahmed. "THE NEW RANK ONE CLASS FOR UNCONSTRAINED PROBLEMS SOLVING". Science Journal of University of Zakho 11, n. 2 (25 aprile 2023): 185–89. http://dx.doi.org/10.25271/sjuoz.2023.11.2.1049.

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Abstract (sommario):

One of the most well-known methods for unconstrained problems is the quasi-Newton approach, iterative solutions. The great precision and quick convergence of the quasi-Newton methods are well recognized. In this work, the new algorithm for the symmetric rank one SR1 method is driven. The strong Wolfe line search criteria deﬁne the step length selection. We also proved the new quasi-Newton equation and positive definite matrix theorem. Preliminary computer testing on the set of fourteen unrestricted optimization test functions leads to the conclusion that this new method is more effective and durable than the implementation of classical SR1 method in terms of iterations count and functions.

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50

Macauley, Natalia, Sichen Zhong, Yachao Zeng, Bingzhang Zhang, Gang Wu e Hui Xu. "Fabrication and Scale-up of Highly Durable Heavy Duty Fuel Cell MEAs". ECS Meeting Abstracts MA2022-01, n. 35 (7 luglio 2022): 1426. http://dx.doi.org/10.1149/ma2022-01351426mtgabs.

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Abstract (sommario):

Medium and heavy-duty PEM fuel cells operate under much harsher conditions than light duty fuel cells and are expected to last 25,000 hours in the field. These systems must therefore operate successfully in the presence of impurities, starting and stopping, freezing and thawing, humidity and load cycling. Therefore, materials, components, and interfaces used in such systems need to be highly resistant to severe mechanical and chemical stress. Novel, highly active stable Pt and ordered PtCo intermetallic nanoparticles with well-controlled particle size and composition have been synthesized on a highly efficient PGM-free single metal active site rich carbon, to maximize their synergistic effects for enhanced performance and durability. These catalysts were integrated with a variety of ionomers (Aquivion, Nafion, HOPI and high O2 permeability ionomer (HOPI)) to further improve fuel cell performance and to achieve >600 mA/mgPt at 0.9 VIR-free with a mass activity loss less than 30% after 150k square wave accelerated durability cycles; and > 600 mA/cm2 (~65% efficiency) at 0.8 V, with a performance loss < 40 mV after 150K cycles (0.6 to 0.95 V). In a PEM fuel cell, the catalyst ink formulation and mixing processes control catalyst layer coating quality, electrode morphology, and the resulting fuel cell performance and durability. Catalyst ink properties are a result of complex solvent-catalyst-ionomer interactions that depend on the mixing method employed. Here, we will compare the performance and durability of electrodes made from bath sonicated inks for ultrasonic spray coating vs. ball milled inks for Meyer rod coating. Ink rheology and catalyst particle size will be used to correlate ink properties to electrode morphology and structure and ensure consistency from batch to batch, and from small lab scale to subsequent scale-up. We will evaluate and discuss the challenges that arise when transitioning from spray coating catalyst ink on a small scale, directly on a membrane, to coating more viscous inks on gas diffusion layers (GDLs), and finally developing a roll-to-roll (R2R) fabrication process. The MEA performance and durability of the novel catalyst will be evaluated under heavy duty operating conditions. Finally, the electrode performance and durability of R2R fabricated GDEs will be tested, and compared to small scale GDEs made at Giner. This work provides a comprehensive understanding of interactions between Pt, PtCo, carbon, ionomer, membrane, and GDLs and their impact on electrode structure, fuel cell performance and durability, as well as considerations for scale up to a R2R fabrication process. The attained information will be used to improve fuel cell electrode design, fabrication and scale-up. Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-FOA-0002360.

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