The Experts below are selected from a list of 4632 Experts worldwide ranked by ideXlab platform
Bharath Bhushan - One of the best experts on this subject based on the ideXlab platform.
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Multifunctional Plant Surfaces and Smart Materials
Springer Handbook of Nanotechnology, 2020Co-Authors: Kerstin Koch, Bharath Bhushan, Wilhelm BarthlottAbstract:The surfaces of plants represent multifunctional interfaces between the organisms and their biotic (living) and the nonbiotic solid, liquid, and gaseous environment. The diversity of plant surface structures has evolved over several hundred million years of evolution. Evolutionary processes have led to a large variety of functional plant surfaces which exhibit, for example, superhydrophobicity, self-cleaning, superhydrophilicity, and reduction of adhesion and light reflection. The primary surface of nearly all parts of land plants is the epidermis. The outer part of epidermal cells is an extracellular membrane called the cuticle. The cuticle, with its associated waxes, is a stabilization element, has a barrier function, and is responsible for various kinds of surface structuring by cuticular folding or deposition of three-dimensional wax crystals on the cuticle. Surface properties, such as superhydrophobicity, self-cleaning, reduction of adhesion and light reflection, and absorption of harmful ultraviolet (UV) radiation, are based on the existence of three-dimensional waxes. Waxes form different morphologies, such as tubules, platelets or rodlets, by self-assembly. The ability of plant waxes to self-assemble into three-dimensional nanostructures can be used to create hierarchical roughness of various kinds of surfaces. The structures and principles which nature uses to develop functional surfaces are of special interest in Biomimetics. Hierarchical structures play a key role in surface wetting and are discussed in the context of superhydrophobic and self-cleaning plants and for the development of biomimetic surfaces. Superhydrophobic biomimetic surfaces are introduced and their use for self-cleaning or development of air-retaining surfaces, for, e.g., drag reduction at surfaces moving in water, are discussed. This chapter presents an overview of plant structures, combines the structural basis of plant surfaces with their functions, and introduces existing biomimetic superhydrophobic surfaces and their fabrication.
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Green Tribology: Biomimetics, Energy Conservation and Sustainability
Green Energy and Technology, 2012Co-Authors: Michael Nosonovsky, Bharath BhushanAbstract:Tribology is the study of friction, wear and lubrication. Recently, the concept of green tribology as the science and technology of the tribological aspects of ecological balance and of environmental and biological impacts was introduced. The field of green tribology includes tribological technology that mimics living nature (biomimetic surfaces) and thus is expected to be environmentally friendly, the control of friction and wear that is of importance for energy conservation and conversion, environmental aspects of lubrication and surface modification techniques, and tribological aspects of green applications such as wind-power turbines or solar panels. This book is the first comprehensive volume on green tribology. The chapters are prepared by leading experts in their fields and cover such topics as Biomimetics, environmentally friendly lubrication, tribology of wind turbines and renewable sources of energy, and ecological impact of new technologies of surface treatment.
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Biomimetics inspired surfaces for drag reduction and oleophobicity philicity
Beilstein Journal of Nanotechnology, 2011Co-Authors: Bharath BhushanAbstract:The emerging field of Biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices, and processes which provide desirable properties. Hierarchical structures with dimensions of features ranging from the macroscale to the nanoscale are extremely common in nature and possess properties of interest. There are a large number of objects including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. Certain plant leaves, such as lotus (Nelumbo nucifera) leaves, are known to be superhydrophobic and self-cleaning due to the hierarchical surface roughness and presence of a wax layer. In addition to a self-cleaning effect, these surfaces with a high contact angle and low contact angle hysteresis also exhibit low adhesion and drag reduction for fluid flow. An aquatic animal, such as a shark, is another model from nature for the reduction of drag in fluid flow. The artificial surfaces inspired from the shark skin and lotus leaf have been created, and in this article the influence of structure on drag reduction efficiency is reviewed. Biomimetic-inspired oleophobic surfaces can be used to prevent contamination of the underwater parts of ships by biological and organic contaminants, including oil. The article also reviews the wetting behavior of oil droplets on various superoleophobic surfaces created in the lab.
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Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity
Beilstein Journal of Nanotechnology, 2011Co-Authors: Bharath BhushanAbstract:The emerging field of Biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices, and processes which provide desirable properties. Hierarchical structures with dimensions of features ranging from the macroscale to the nanoscale are extremely common in nature and possess properties of interest. There are a large number of objects including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. Certain plant leaves, such as lotus (Nelumbo nucifera) leaves, are known to be superhydrophobic and self-cleaning due to the hierarchical surface roughness and presence of a wax layer. In addition to a self-cleaning effect, these surfaces with a high contact angle and low contact angle hysteresis also exhibit low adhesion and drag reduction for fluid flow. An aquatic animal, such as a shark, is another model from nature for the reduction of drag in fluid flow. The artificial surfaces inspired from the shark skin and lotus leaf have been created, and in this article the influence of structure on drag reduction efficiency is reviewed. Biomimetic-inspired oleophobic surfaces can be used to prevent contamination of the underwater parts of ships by biological and organic contaminants, including oil. The article also reviews the wetting behavior of oil droplets on various superoleophobic surfaces created in the lab.
Friedrich Roth - One of the best experts on this subject based on the ideXlab platform.
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Extreme Biomimetics: A carbonized 3D spongin scaffold as a novel support for nanostructured manganese oxide(IV) and its electrochemical applications
Nano Research, 2018Co-Authors: Tomasz Szatkowski, Beata Mania, Vasilii V Bazhenov, Kacper Kopczynski, Horst Borrmann, Grzegorz Lota, David Rafaja, Mykhailo Motylenko, Małgorzata Graś, Friedrich RothAbstract:Composites containing biological materials with nanostructured architecture have become of great interest in modern materials science, yielding both interesting chemical properties and inspiration for biomimetic research. Herein, we describe the preparation of a novel 3D nanostructured MnO_2-based composite developed using a carbonized proteinaceous spongin template by an extreme Biomimetics approach. The thermal stability of the spongin-based scaffold facilitated the formation of both carbonized material (at 650 °C with exclusion of oxygen) and manganese oxide with a defined nanoscale structure under 150 °C. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydrothermal processing, yielding a novel porous support. The MnO_2-spongin composite shows a bimodal pore distribution, with macropores originating from the spongin network and mesopores from the nanostructured oxidic coating. Interestingly, the composites also showed improved electrochemical properties compared to those of MnO_2. Voltammetry cycling demonstrated the good stability of the material over more than 3,000 charging/discharging cycles. Additionally, electrochemical impedance spectroscopy revealed lower charge transfer resistance in the prepared materials. We demonstrate the potential of extreme Biomimetics for developing a new generation of nanostructured materials with 3D centimeter-scale architecture for the storage and conversion of energy generated from renewable natural sources.
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extreme Biomimetics a carbonized 3d spongin scaffold as a novel support for nanostructured manganese oxide iv and its electrochemical applications
Nano Research, 2018Co-Authors: Tomasz Szatkowski, Beata Mania, Vasilii V Bazhenov, Kacper Kopczynski, Malgorzata Cieśla, Horst Borrmann, Grzegorz Lota, David Rafaja, Mykhailo Motylenko, Friedrich RothAbstract:Composites containing biological materials with nanostructured architecturehave become of great interest in modern materials science, yielding both interestingchemical properties and inspiration for biomimetic research. Herein, we describe thepreparation of a novel 3D nanostructured MnO2-based composite developed usinga carbonized proteinaceous spongin template by an extreme Biomimetics approach. The thermal stability of the spongin-based scaffold facilitated the formation of both carbonized material (at 650 °C with exclusion of oxygen) and manganese oxide with a defined nanoscale structure under 150 °C. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydrothermalprocessing, yielding a novel porous support. The MnO2-spongin composite shows a bimodal pore distribution, with macropores originating from the sponginnetwork and mesopores from the nanostructured oxidic coating. Interestingly,the composites also showed improved electrochemical properties compared tothose of MnO2. Voltammetry cycling demonstrated the good stability of the materialover more than 3,000 charging/discharging cycles. Additionally, electrochemicalimpedance spectroscopy revealed lower charge transfer resistance in the preparedmaterials. We demonstrate the potential of extreme Biomimetics for developing a new generation of nanostructured materials with 3D centimeter-scale architecturefor the storage and conversion of energy generated from renewable natural sources. Open image in new window
Volker Sieber - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Biomimetic Cofactors According to Stability, Redox Potentials, and Enzymatic Conversion by NADH Oxidase from Lactobacillus pentosus.
Chembiochem : a European journal of chemical biology, 2017Co-Authors: Claudia Nowak, André Pick, Lénárd-istván Csepei, Volker SieberAbstract:Oxidoreductases are attractive biocatalysts that convert achiral substrates into products of higher value, but they are also for the most part dependent on nicotinamide cofactors. Recently, biomimetic nicotinamide derivatives have received attention as less costly alternatives to natural cofactors. However, recycling of Biomimetics is still challenging because there are only limited opportunities. Here, we have characterized various biomimetic cofactors with regard to stability and redox potentials to find the best alternative to natural cofactors. Further, the cofactor spectrum of NADH oxidase from Lactobacillus pentosus (LpNox) could be expanded, and the enzymatic activity was also compared to activities with different small-molecule catalysts. As a result, we succeeded in identifying several strategies for regeneration of oxidized Biomimetics.
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Enzymatic Reduction of Nicotinamide Biomimetic Cofactors Using an Engineered Glucose Dehydrogenase: Providing a Regeneration System for Artificial Cofactors
2017Co-Authors: Claudia Nowak, André Pick, Petra Lommes, Volker SieberAbstract:The increasing demand for chiral compounds supports the development of enzymatic processes. Dehydrogenases are often the enzymes of choice due to their high enantioselectivity combined with broad substrate acceptance. However, their requirement on costly NAD(P)/H as cofactor has sparked interest in the development of biomimetic derivatives that are easy to synthesize and, therefore, less expensive. Until now, few reactions with Biomimetics have been described and regeneration is limited to nonenzymatic means, which are not suitable for incorporation and in situ approaches. Herein, we describe a regeneration enzyme, glucose dehydrogenase from Sulfolobus solfataricus (SsGDH), and demonstrate its activity with different Biomimetics with the structure nicotinamide ring-alkyl chain-phenyl ring. Subsequent enzyme engineering resulted in the double mutant SsGDH Ile192Thr/Val306Ile, which had a 10-fold higher activity with one of the Biomimetics compared with the wild-type enzyme. Using this engineered variant in combination with an enoate reductase from Thermus scotoductus resulted in the first enzyme-coupled regeneration process for biomimetic cofactor without ribonucleotide or ribonucleotide analogue and full conversion of 10 mM 2-methylbut-2-enal with 1-phenethyl-1,4-dihydropyridine-3-carboxamide as cofactor
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a water forming nadh oxidase from lactobacillus pentosus suitable for the regeneration of synthetic biomimetic cofactors
Frontiers in Microbiology, 2015Co-Authors: Claudia Nowak, André Pick, Petra Lommes, Barbara Beer, Teresa Roth, Volker SieberAbstract:The cell-free biocatalytic production of fine chemicals by oxidoreductases has continuously grown over the past years. Since especially dehydrogenases depend on the stoichiometric use of nicotinamide pyridine cofactors, an integrated efficient recycling system is crucial to allow process operation under economic conditions. Lately, the variety of cofactors for biocatalysis was broadened by the utilization of totally synthetic and cheap Biomimetics. Though, to date the regeneration has been limited to chemical or electrochemical methods. Here, we report an enzymatic recycling by the flavoprotein NADH-oxidase from Lactobacillus pentosus (LpNox). Since this enzyme has not been described before, we first characterized it in regard to its optimal reaction parameters. We found that the heterologously overexpressed enzyme only contained 13 % FAD. In vitro loading of the enzyme with FAD, resulted in a higher specific activity towards its natural cofactor NADH as well as different nicotinamide derived Biomimetics. Apart from the enzymatic recycling, which gives water as a by-product by transferring four electrons onto oxygen, unbound FAD can also catalyse the oxidation of biomimetic cofactors. Here a two electron process takes place yielding H2O2 instead. The enzymatic and chemical recycling was compared in regard to reaction kinetics for the natural and biomimetic cofactors. With LpNox and FAD, two recycling strategies for biomimetic cofactors are described with either water or hydrogen peroxide as a by-product.
Tomasz Szatkowski - One of the best experts on this subject based on the ideXlab platform.
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Extreme Biomimetics: A carbonized 3D spongin scaffold as a novel support for nanostructured manganese oxide(IV) and its electrochemical applications
Nano Research, 2018Co-Authors: Tomasz Szatkowski, Beata Mania, Vasilii V Bazhenov, Kacper Kopczynski, Horst Borrmann, Grzegorz Lota, David Rafaja, Mykhailo Motylenko, Małgorzata Graś, Friedrich RothAbstract:Composites containing biological materials with nanostructured architecture have become of great interest in modern materials science, yielding both interesting chemical properties and inspiration for biomimetic research. Herein, we describe the preparation of a novel 3D nanostructured MnO_2-based composite developed using a carbonized proteinaceous spongin template by an extreme Biomimetics approach. The thermal stability of the spongin-based scaffold facilitated the formation of both carbonized material (at 650 °C with exclusion of oxygen) and manganese oxide with a defined nanoscale structure under 150 °C. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydrothermal processing, yielding a novel porous support. The MnO_2-spongin composite shows a bimodal pore distribution, with macropores originating from the spongin network and mesopores from the nanostructured oxidic coating. Interestingly, the composites also showed improved electrochemical properties compared to those of MnO_2. Voltammetry cycling demonstrated the good stability of the material over more than 3,000 charging/discharging cycles. Additionally, electrochemical impedance spectroscopy revealed lower charge transfer resistance in the prepared materials. We demonstrate the potential of extreme Biomimetics for developing a new generation of nanostructured materials with 3D centimeter-scale architecture for the storage and conversion of energy generated from renewable natural sources.
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extreme Biomimetics a carbonized 3d spongin scaffold as a novel support for nanostructured manganese oxide iv and its electrochemical applications
Nano Research, 2018Co-Authors: Tomasz Szatkowski, Beata Mania, Vasilii V Bazhenov, Kacper Kopczynski, Malgorzata Cieśla, Horst Borrmann, Grzegorz Lota, David Rafaja, Mykhailo Motylenko, Friedrich RothAbstract:Composites containing biological materials with nanostructured architecturehave become of great interest in modern materials science, yielding both interestingchemical properties and inspiration for biomimetic research. Herein, we describe thepreparation of a novel 3D nanostructured MnO2-based composite developed usinga carbonized proteinaceous spongin template by an extreme Biomimetics approach. The thermal stability of the spongin-based scaffold facilitated the formation of both carbonized material (at 650 °C with exclusion of oxygen) and manganese oxide with a defined nanoscale structure under 150 °C. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydrothermalprocessing, yielding a novel porous support. The MnO2-spongin composite shows a bimodal pore distribution, with macropores originating from the sponginnetwork and mesopores from the nanostructured oxidic coating. Interestingly,the composites also showed improved electrochemical properties compared tothose of MnO2. Voltammetry cycling demonstrated the good stability of the materialover more than 3,000 charging/discharging cycles. Additionally, electrochemicalimpedance spectroscopy revealed lower charge transfer resistance in the preparedmaterials. We demonstrate the potential of extreme Biomimetics for developing a new generation of nanostructured materials with 3D centimeter-scale architecturefor the storage and conversion of energy generated from renewable natural sources. Open image in new window
Lu Quan Ren - One of the best experts on this subject based on the ideXlab platform.
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comparison of thermal fatigue behaviour and microstructure of different hot work tool steels processed by biomimetic couple laser remelting process
Materials Science and Technology, 2013Co-Authors: Chao Meng, Dalong Cong, Chuanwei Wang, Hong Zhou, Xin Tong, Lu Quan RenAbstract:AbstractFor comparing the enhancement degree of the thermal fatigue behaviour of different hot work tool steels processed by laser remelting, three kinds of hot work tool steels (HHD, H13 and HD steels) were selected to investigate the effect of biomimetic coupled laser remelting process on the thermal fatigue behaviour. The results showed that biomimetic non-smooth samples had better thermal fatigue behaviour compared to untreated samples, the biomimetic non-smooth sample of HHD had the optimum thermal fatigue behaviour. Moreover, before and after thermal fatigue testing, the microhardness and microstructure of biomimetic non-smooth units and parent materials have been investigated. The results showed that biomimetic non-smooth sample of HHD had the highest resistance of thermal cycles softening among the biomimetic non-smooth samples. The microstructures observation indicated that the microstructures of parent materials were a substantial amount of the carbides coarsening while the microstructures of bi...
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Researches and developments of Biomimetics in tribology
Chinese Science Bulletin, 2006Co-Authors: Zhendong Dai, Jin Tong, Lu Quan RenAbstract:Animals and plants have developed optimal geometric structures, smart topological ma- terials and multi-functional surface textures with ex- cellent tribological characteristics through the evolu- tion of thousand millions of years and become mod- els for tribological design. This paper puts forward the definition and fundament of biomimetic tribology, in- vestigates the status of self-cleaning of liquid-solid interface, adhesion between animals’ feet and solid surface, wear characteristics of biological surfaces and biomimetic design, as well as the friction and bionic design on liquid-solid interface. The further developments of the tribological Biomimetics are discussed.
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Soil Adhesion and Biomimetics of Soil-engaging Components: a Review
Journal of Agricultural Engineering Research, 2001Co-Authors: Lu Quan Ren, Jian-qiao Li, Jin Tong, Bing-cong ChenAbstract:Adhesive forces exist between soil and the surfaces of soil-engaging components on a variety of terrain machines including tillage and sowing machines. This phenomenon of soil adhesion not only increases the working resistance and energy consumption of these machines, but also decreases the quality of work. Characteristics of soil adhesion to solid surfaces, behaviour and principles of soil-burrowing animals for improved soil scouring and Biomimetics of soil-engaging components are reviewed in this paper. The characteristics of soil adhesion to solid surfaces were concerned with: the morphological features of soil at the contact interfaces, contact models of soil adhesion, explanation of soil adhesion, factors affecting soil adhesion and conventional methods for reducing adhesion. Details on the behaviour of soil-burrowing animals include: claw shape; body surface geometry, chemical constitution, liquid secretion and bioelectricity; and body flexing behaviour. The principles of soil-burrowing animals in soil scouring mainly comprise the effects of geometrical morphologies and shapes, hydrophobicity, micro-electro-osmotic systems, lubrication and body surface flexibility. Based on these characteristics, biomimetic methods for reducing soil adhesion to soil-engaging components include: biomimetic non-smooth surfaces; modification of soil-engaging materials; biomimetic non-smooth electro-osmosis; and flexible components.