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71.
Veronika Tunakova Maros Tunak Jana Mullerova Marcela Kolinova Vaclav Bittner 《纺织学会志》2017,108(12):2132-2146
The main objective of this paper is to determine material composition, structure, and chosen mechanical and thermo-physiological comfort properties of selected kinesiology tape. The results of experiments show that kinesiology tape is a non-linear elastic and porous composite material. Warp yarns are core-spun elastic yarns, while weft yarns are 100% cotton yarns. Fabric has a plain weave and its back side is equipped with an adhesive. Tensile strength of kinesiology tape ranges from 80 to 180 N depending on the tape width. In a relaxed state, porosity together with air permeability and other heat and mass transfer characteristics are mainly affected by the compact layer of adhesive on the surface of woven fabric. During tensioning, pores are expanding and therefore transfer of air and water vapor is significantly increased and at the same time heat transfer is reduced which can positively affect wearer comfort. 相似文献
72.
The paper reports on a reactive deposition of transparent SiO2 films with a low amount (≤ 3 at.%) of Zr prepared from the molten target using the AC pulsed dual magnetron. It is shown that the deposition rate aD of the transparent oxide film strongly increases at the critical target power density (Wt)cr when the solid target starts to melt and the magnetron operates with a molten target. In this case, the evaporation of target material plays a dominant role in the reactive deposition of thin films. This process is called the ionized magnetron evaporation. Oxide films reactively deposited from the molten target are well transparent and highly elastic. The maximum deposition rate of the transparent oxide film achieved in our experiments is 814 nm/min. 相似文献
73.
Carmen Téllez-Pérez Vaclav Sobolik José Gerardo Montejano-Gaitán Galal Abdulla 《Drying Technology》2013,31(2):131-142
The impacts of total hot air drying (THD) and the swell-drying process (SD), which is hot air drying coupled with an instant controlled pressure drop DIC process, on the drying kinetics and adsorption isotherm behavior, were determined in the case of Moroccan peppers. Drying kinetics were studied through a model that takes into account the starting accessibility and the internal diffusion model with Fick's law. Adsorption experimental data were obtained by using the gravimetric method at 25, 40, and 50°C. Data were fitted to the GAB, Halsey, and Oswin models. Studied responses were: effective diffusivity (Deff), starting accessibility (δWs), monolayer moisture content (Xm), specific surface area (σ), internal porosity (?), and microstructure. Mean relative percentage deviation (E) and root mean square (RMS) were used to evaluate the fitting of models. Results showed that: pepper adsorption isotherms followed the type II isotherm curve;the equilibrium moisture content (Xeq) depended on the temperature and the drying method; the GAB and Halsey models fitted well the experimental data; at selected conditions of the DIC treatment (0.35 MPa and 5 s), the monolayer moisture content (Xm), the specific surface area (σ), and the internal porosity values were higher than those of THD samples; the DIC process intensified the drying operation, by increasing the effective diffusivity and the starting accessibility. Although the DIC process improves the drying kinetics, this behavior could be ignored related to a higher aw. This study shows that, thanks to the new expanded structure obtained by the DIC process (higher porosity), the adsorption capacities of products are improved (aw is reduced). Thus, the SD process improves both the drying operation and the stability of dried pepper products. 相似文献
74.
75.
Vaclav Dolezal 《Circuits, Systems, and Signal Processing》1995,14(2):135-143
We study the behavior of a Hilbert network (i.e., a finite or countably infinite network whose variables are in a Hilbert space and in which the associated total energy is finite) whose elements are affected by perturbations. More specifically, we will give estimates for a change of the current distribution caused by (a) perturbations of the elements of the nominal network when the voltage sources are fixed, and (b) a change of voltage sources in a network whose elements are perturbed. The conditions given in our theorems imply insensitivity and robust stability of the nominal network. The applications of the results are illustrated by an example of an infinite network.This research was supported by the NSF Grant #DMS-9102910. 相似文献
76.
Okpeafoh S. Agimelen Vaclav Svoboda Bilal Ahmed Javier Cardona Jerzy Dziewierz Cameron J. Brown Thomas McGlone Alison Cleary Christos Tachtatzis Craig Michie Alastair J. Florence Ivan Andonovic Anthony J. Mulholland Jan Sefcik 《Advanced Powder Technology》2018,29(12):2987-2995
Size and shape distributions are among critical quality attributes of particulate products and their inline measurement is crucial for monitoring and control of particle manufacturing processes. This requires advanced tools that can estimate particle size and shape distributions from multi-sensor data captured in situ across various processing steps.In this work, we study changes in size and shape distributions, as well as number of particles during high shear wet milling, which is increasingly being employed for size reduction in crystalline slurries in pharmaceutical processing. Saturated suspensions of benzoic acid, paracetamol and metformin hydrochloride were used in this study. We employ our recently developed tools for estimating particle aspect ratio and particle size distributions from chord length distribution (CLD) measurements and imaging. We also compare estimated particle size distributions from CLD and imaging with corresponding estimates from offline instruments.The results show that these tools are capable of quantitatively capturing changes in particle sizes and shape during wet milling inline. This is the first time that such a capability has been reported in the literature. The ability to quantitatively monitor particle size and shape distributions in real time will enable development of more realistic and accurate population balance models of wet milling and crystallisation, and aid more efficient control of crystallisation processes. 相似文献
77.
Ultrathin Hierarchical Porous Carbon Nanosheets for High‐Performance Supercapacitors and Redox Electrolyte Energy Storage 下载免费PDF全文
Kolleboyina Jayaramulu Deepak P. Dubal Bhawna Nagar Vaclav Ranc Ondrej Tomanec Martin Petr Kasibhatta Kumara Ramanatha Datta Radek Zboril Pedro Gómez‐Romero Roland A. Fischer 《Advanced materials (Deerfield Beach, Fla.)》2018,30(15)
The design of advanced high‐energy‐density supercapacitors requires the design of unique materials that combine hierarchical nanoporous structures with high surface area to facilitate ion transport and excellent electrolyte permeability. Here, shape‐controlled 2D nanoporous carbon sheets (NPSs) with graphitic wall structure through the pyrolysis of metal–organic frameworks (MOFs) are developed. As a proof‐of‐concept application, the obtained NPSs are used as the electrode material for a supercapacitor. The carbon‐sheet‐based symmetric cell shows an ultrahigh Brunauer–Emmett–Teller (BET)‐area‐normalized capacitance of 21.4 µF cm?2 (233 F g?1), exceeding other carbon‐based supercapacitors. The addition of potassium iodide as redox‐active species in a sulfuric acid (supporting electrolyte) leads to the ground‐breaking enhancement in the energy density up to 90 Wh kg?1, which is higher than commercial aqueous rechargeable batteries, maintaining its superior power density. Thus, the new material provides a double profits strategy such as battery‐level energy and capacitor‐level power density. 相似文献
78.
Nanoporous Nitrogen‐Doped Graphene Oxide/Nickel Sulfide Composite Sheets Derived from a Metal‐Organic Framework as an Efficient Electrocatalyst for Hydrogen and Oxygen Evolution 下载免费PDF全文
Kolleboyina Jayaramulu Justus Masa Ondrej Tomanec Daniel Peeters Vaclav Ranc Andreas Schneemann Radek Zboril Wolfgang Schuhmann Roland A. Fischer 《Advanced functional materials》2017,27(33)
Engineering of controlled hybrid nanocomposites creates one of the most exciting applications in the fields of energy materials and environmental science. The rational design and in situ synthesis of hierarchical porous nanocomposite sheets of nitrogen‐doped graphene oxide (NGO) and nickel sulfide (Ni7S6) derived from a hybrid of a well‐known nickel‐based metal‐organic framework (NiMOF‐74) using thiourea as a sulfur source are reported here. The nanoporous NGO/MOF composite is prepared through a solvothermal process in which Ni(II) metal centers of the MOF structure are chelated with nitrogen and oxygen functional groups of NGO. NGO/Ni7S6 exhibits bifunctional activity, capable of catalyzing both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) with excellent stability in alkaline electrolytes, due to its high surface area, high pore volume, and tailored reaction interface enabling the availability of active nickel sites, mass transport, and gas release. Depending on the nitrogen doping level, the properties of graphene oxide can be tuned toward, e.g., enhanced stability of the composite compared to commonly used RuO2 under OER conditions. Hence, this work opens the door for the development of effective OER/HER electrocatalysts based on hierarchical porous graphene oxide composites with metal chalcogenides, which may replace expensive commercial catalysts such as RuO2 and IrO2. 相似文献
79.
Vaclav Dolezal 《Circuits, Systems, and Signal Processing》1998,17(6):683-690
The objective of this paper is to present certain conditions guaranteeing invertibility of a nonlinear operator between normed linear spaces. The idea is to approximate the given operator by an invertible, possibly linear operator, and reduce the problem to the contraction mapping principle. Several theorems of this kind are given, which appear as generalizations of some early results by I.W. Sandberg, and estimates for an approximate inverse are established. Finally, introducing certain invertibility indices, further sufficient and necessary conditions for invertibility are given. 相似文献
80.
Zuzana Hejdankova Vaclav Vanek Frantisek Sedlak Jan Prochazka Audrey Diederichs Sami Kereïche Barbora Novotna Milos Budesinsky Gabriel Birkus Klara Grantz Saskova Petr Cigler 《Advanced functional materials》2021,31(47):2101391
Lipid nanoparticles (LNPs) are the most advanced nonviral modality for nucleic acid (NA) delivery, and have recently gained enormous attention in the fields of RNA therapeutics and vaccine development. Here, ionizable adamantane-based lipidoids named XMaNs, which circumvent the usual need for laborious optimization of LNP components for highly diverse types of NAs, are described. The non-toxic XMaN6 lipidoid is highly versatile in entrapment and delivery of siRNA, mRNA, plasmid DNA, and a cyclic dinucleotide. XMaN6-based LNPs efficiently deliver: 1) siRNA into human primary hepatocytes and cell lines that are hard-to-transfect; 2) mRNA into mouse liver; 3) plasmid DNA; 4) 2′,3′-cGAMP into cells and activated the cGAS-STING pathway three orders of magnitude more efficiently than 2′,3′-cGAMP alone. To our knowledge, such universality in delivering different NA types has not been previously described and can accelerate translation of LNPs into the clinic. 相似文献