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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: POLYMER DERIVED CERAMICS
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Compatibilization of polymeric composition filled with ground tire rubber – short review
PublikacjaWaste rubber is recognized as valuable materials resource and searching for new recycling methods is the main activity of many research institutions and companies. At the turn of the last years only few scientific papers about foamed polymer compositions filled with ground tire rubber were published. In paper review about progress in compatibilization and foaming of polymeric compositions filled with ground tire rubber.
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On geometrically non-linear FEA of laminated FRP composite panels
PublikacjaThe paper presents a state-of-art review on Finite Element Analysis (FEA) of geometrically non-linear problems for laminated composite plates and shells made as fibre reinforced polymer (FRP) laminates. Besides a subjective overview of the historical development of geometrically non-linear FEA of laminated FRP composite panels, some remarks on possible future issues in this research area are given
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Determination of the shape of the CFGFT cylindrical column based on laboratory tests
PublikacjaAnalyses were carried out on glass-fibre-reinforced polymer tube columns with reference to laboratory tests. The angles of the glass fibre beams were 20◦, 55◦ and 85◦. The study employed non-classical operational calculus. Various modulated harmonic signal shapes were considered for columns and tubes at buckling. The buckling loads were assessed and compared for different models.
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An Influence of Factors of Flow Condition, Particle and Material Properties on Slurry Erosion Resistance
PublikacjaThe degradation of materials due to slurry erosion is the serious problem which occurs in the power industries. The paper presents actual knowledge about an influence of individual factors connected with flow conditions, particles and material properties on the slurry erosion resistance. Among the factors connected with operating conditions, an influence of impact angle, and velocity of impact, particle concertation and liquid...
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Dissolution of Nb-doped hydroxyapatite prepared via low-temperature mechanochemical method: Spectroscopy studies
PublikacjaCalcium phosphate glass ceramics with nominal hydroxyapatite stoichiometry doped with niobium were synthesized using simple as well as low-temperature mechanochemical method and then in the form of compressed pellet were submitted to the static dissolution process in distilled water for one month. The results of structural analysis, performed mainly on the base of spectroscopic methods such as: infrared absorption spectroscopy,...
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Structure and transport properties of donor-doped barium strontium cobaltites
PublikacjaIn this work, Nb-substituted barium strontium cobaltites Ba0.5Sr0.5Co1-xNbxO3-δ (x = 0 – 0.4) have been fabricated and studied. The structural analysis showed that the Nb content influences the lattice constant as well as the distance between the (Co, Nb) and oxygen atoms. The study of morphology of samples showed that the Nb content does not change the porosity, grain size and morphology of the ceramics. The total electrical conductivity...
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QUASI-DISTRIBUTED NETWORK OF LOW-COHERENCE FIBER-OPTIC FABRY-PÉROT SENSORS WITH CAVITY LENGTH-BASED ADDRESSING
PublikacjaDistributed measurement often relies on sensor networks. In this paper, we present the construction of low coherent fiber-optic Fabry-Pérot sensors connected into a quasi-distributed network. We discuss the mechanism of spectrum modulation in this type of sensor and the constraints of assembly of such sensors in the network. Particular attention was paid to separate the signals from individual sensors, which can be achieved by...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
PublikacjaNew phosphate glasses and glass-ceramics P2O5–Bi2O3–K2O–Nb2O5-SrF2 doped with Eu were synthesized and studied in this work. The influence of the SrF2 content (0–15 mol%) and the parameters of the heat treatment on their structural and optical properties were investigated. For the above purpose, the structural characterization by FTIR spectroscopy and XRD measurements was carried out, which showed a significant effect of SrF2 on...
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Orthogonality relations for the associated Legendre functions of imaginary order
PublikacjaOrthogonality relations for the associated Legendre functions of imaginary order are derived. They are expressed in terms of the Dirac delta function. The method is based on some known properties of the associated Legendre functions and the Dirac delta distribution. A special case of one of the relations has appeared in some recent applications.
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Supporting compliance with safety standards by trust case templates
PublikacjaStandard Compliance (SC) Framework presented in this paper encompasses methods and tools which provide support for application of standards. The framework is based on trust case methodology. A trust case is a data structure which represents a justification that an object (a system, an infrastructure, an organization) exhibits certain properties. It contains an argument and related evidence which support claimed properties. A trust...
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Assessment of Therapeutic Progress After Acquired Brain Injury Employing Electroencephalography and Autoencoder Neural Networks
PublikacjaA method developed for parametrization of EEG signals gathered from participants with acquired brain injuries is shown. Signals were recorded during therapeutic session consisting of a series of computer assisted exercises. Data acquisition was performed in a neurorehabilitation center located in Poland. The presented method may be used for comparing the performance of subjects with acquired brain injuries (ABI) who are involved...
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Introduction of SAF-T in selected European countries together with applicable national names
Dane BadawczeAmong the methods used by individual countries in norder to seal the tax collection the introduction of the Standard Audit File for Tax is one of the most important ones.
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Analiza nieliniowa powłok z materiałów gradientowych w ośrodku mikropolarnym
PublikacjaW pracy zaprezentowano analizę powłok z materiałów gradientowych dla zakresu dużych przemieszczeń. Macierz konstytutywna została wyprowadzona dla elementu powłokowego o 6 stopniach swobody w węźle w teorii ośrodka mikropolarnego. Zaprezentowano wyniki numeryczne dla swobodnie podpartej kwadratowej płyty FGM i porównano je z wynikami z literatury oraz uzyskanymi w programie Abaqus.
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Variable Temperature Spectroscopic Ellipsometry as a Tool for Insight into the Optical Order in the P3HT:PC70BM and PC70BM Layers
PublikacjaTwo combined ellipsometric techniques—variable angle spectroscopic ellipsometry (VASE) and variable temperature spectroscopic ellipsometry (VTSE)—were used as tools to study the surface order and dielectric properties of thin films of a poly(3-hexylthiophene-2,5-diyl) (P3HT) mixture with a fullerene derivative (6,6-phenyl-C71-butyric acid methyl ester) (PC70BM). Under the influence of annealing, a layer of the ordered PC70BM...
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Preparation and characterisation of solution-cast Nafion membrane
PublikacjaNafion is a commercial name for a perfluorosulfonic polymer, which has been developed in 1962 by Dupont de Nemours. This polymer consists of a polytetrafluoroethylene backbone and regular spaced long perfluorovinyl ether pendant side chains terminated by a sulfonate ionic group. These sulfonate groups are responsible for cation-exchange properties of Nafion. Thanks to the ion-exchange properties, water permeability, good chemical,...
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The application of a photopolymer material for the manufacture of machine elements using rapid prototyping techniques
PublikacjaThe paper discusses the application of polymer resin for 3D printing. The first section focuses on rapid prototyping technique and properties of the photopolymer, used as input material in the manufacture of machine components. Second part of the article was devoted to exemplary 3-D-printed elements for incorporation in machines. The article also contains detailed description of problems encountered in implementation of the selected...
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Hip endhoprothesis development using rapid prototyping methods
PublikacjaIntegrated product development based on Rapid Prototyping methods, connected with computer aided 3D design and computer aided engineering enables fast and full new product verification and validation. A case study derived from clinical and technological practice using hip implant construction is also included.
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The POCOBIO Database for Computed Scattering Cross-Sections for Positron Collisions with Biomolecular Systems
PublikacjaThe design of a database for positron interactions with biomolecular systems is outlined. The database contains only scattering cross sections, which are derived from theory. The data model is defined in a very flexible way, which facilitates the usage of weakly bound clusters of molecules and molecular systems with many tautomeric forms.
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Bending of a Three-Layered Plate with Surface Stresses
PublikacjaWe discuss here the bending deformations of a three-layered plate taking into account surface and interfacial stresses. The first-order shear deformation plate theory and the Gurtin-Murdoch model of surface stresses will be considered and the formulae for stiffness parameters of the plate are derived. Their dependence on surface elastic moduli will be analyzed.
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Influence of bitumen type on cracking resistance of asphalt mixtures used in pavement overlays
PublikacjaCracking is one of the predominant distresses occurring in flexible pavements, especially in old pavements that were rehabilitated with an asphalt overlay. In such cases asphalt mixtures should be designed to ensure high resistance to reflective cracking because new asphalt layers are exposed to existing cracks of the old pavement. The nature of these cracks can be various (transverse, longitudinal as well as crazy cracking). One...
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Local impedance spectra of organic coatings
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Development of stabilized protonconducting membrane based on poly(ethylene-co-vinyl alcohol)
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Sulfonated poly(benzoyl paraphenylene) as a membrane for PEMFC: Ex situ and in situ experiments of thermal and chemical stability
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Comparison of the effect of montmorillonite, magnesium hydroxide and a mixture of both on the flammability properties and mechanism of char formation of HDPE composites
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Preparation and characterization of rigid polyurethane–polyglycerol nanocomposite foams
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Incorporation of magnetite particles in 3D matrices made from the blends of collagen, chitosan, and hyaluronic acid
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Influence of nitrogen plasma treatment on the wettability of polyetheretherketone and deposited chitosan layers
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The impact of lignin addition on the properties of hybrid microspheres based on trimethoxyvinylsilane and divinylbenzene
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Mechanical and thermal analysis of injection molded poly(methyl methacrylate) modified with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) fire retarder
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Identification and localization of organic coating degradation onset by impedance imaging
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Kinetics and Mechanism of Potassium Persulphate/L-Serine Initiated Polymerization of Methylmethacrylate
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Saturation ESR spectroscopy of PA12 polyamide
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Dispersing hydrophilic nanoparticles in hydrophobic polymers: HDPE/ZnO nanocomposites by a novel template-based approach
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Synergistic effect of activated carbon and Ni2O3 in promoting the thermal stability and flame retardancy of polypropylene
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Recent progress in controlled carbonization of (waste) polymers
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Synergistic effect of fumed silica with Ni2O3 on improving flame retardancy of poly(lactic acid)
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Influence of modified attapulgite on silicone pressure-sensitive adhesives properties
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Effect of bio-based components on the chemical structure, thermal stability and mechanical properties of green thermoplastic polyurethane elastomers
PublikacjaIt seems to be obvious that conditions changes during polyols synthesis have impact on the polyols properties. Even the chemical formula is the same or similar, physicochemical properties and also molecular weight of polyols might be different and are significant in term of future polyurethanes properties and processing. In this work, fully bio-based poly(propylene succinate)s synthesized at different temperature conditions were...
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A comprehensive evaluation of flexible FDM/FFF 3D printing filament as a potential material in medical application
PublikacjaThe use of FDM/FFF in 3D printing for medical sciences is becoming common. This is due to the high availability and decent price of both 3D printers and filaments useful for FDM/FFF. Currently, researchers' attention is focused mainly on the study of medical filaments based on PLA, PCL or their modifications. This contributes to insufficient diversity of medical-grade filaments on the market. Moreover, due to the lack of specified...
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Reactive extrusion of biodegradable aliphatic polyesters in the presence of free-radical-initiators: A review
PublikacjaNowadays, growing attention is being paid to the environment and sustainability, what fully justified research works focused on modification of biodegradable polymers and their composites. In this field of research reactive extrusion seems to be the most promising approach, which fits well to sustainable development strategy. In In the present work, the in-situ modification of biodegradable aliphatic polyesters and the compatibilization...
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Assessment of the devulcanization process of EPDM waste from roofing systems by combined thermomechanical/microwave procedures
PublikacjaEthylene-propylene-diene rubber (EPDM) is a elastomer widely used in common industrial applications. EPDM can be shaped into sheets and employed as isolating material for roofing systems. In this study, scraps of EPDM from commercial, industrial and residential roofing systems were treated by combined thermo-mechanical and microwave devulcanization processes including peroxide of benzoyl (BPO). The devulcanized EPDM (Dev-EPDM)...
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Fully bio-based poly(propylene succinate) synthesis and investigation of thermal degradation kinetics with released gases analysis
PublikacjaOne of the most important information about polyesters is their thermal stability and phase transition tem- peratures. These characteristics give information about the promising behavior of the polyester during proces- sing. In this work, linear bio-based polyester polyols were prepared with the use of succinic acid and 1.3- propanediol (both with natural origin). As a polycondensation catalyst was used tetraisopropyl orthotitanate...
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Preparation and characterization of rigid polyurethane-polyglycerolnanocomposite foams
PublikacjaThis work reports on the preparation of polyurethane-polyisocyanurate (PUR-PIR) foams containing different polyglycerols and layered silicate nanoclays. The rigid polyurethane foams were obtained in a laboratory scale, in a single step method, from a two-component system with a NCO to OH groups ratio equal to two. The reaction mixture consisted of the proper amounts of a commercial oligoetherpolyol, polyglycerol, catalysts, water,...
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Local impedance spectra of organic coatings
PublikacjaPublikacja przedstawia nowe podejście do lokalnych spektroskopowych pomiarów impedancyjnych powłok organicznych, oparte o mikroskop sił atomowych pracujący w trybie kontaktowym. Pomiędzy nieporuszającą się igłę mikroskopu i podłoże metalowe pokryte powłoką epoksydową przyłożono serię sinusoidalnych napięciowych sygnałów pobudzenia w zadanym zakresie częstotliwości. W ten sposób zarejestrowano lokalne widma w trybie "frequency by...
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Microwave radiation in the synthesis of urethane prepolymers
PublikacjaThis paper describes the use of microwave radiation in the synthesis of urethane prepolymers in bulk (without solvent). The prepolymers were synthesized using 1,6-hexamethylene diisocyanate (HDI) and poly (ε-caprolactone) diol (PCL) at a molar ratio of 4:1. The reaction was carried out without a catalyst in the reactor with a conventional heating system (oil bath) or in the microwave reactor (MW Reactor NOVA 09) at temperatures...
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Processing, physico-mechanical and thermal properties of reclaimed GTR and NBR/reclaimed GTR blends as function of various additives
PublikacjaIn this work, ground tire rubber (GTR) was mechano-chemically reclaimed in the presence of bitumen and various additives. During studies three types of processing and curing additives: (i) peptizer P300; (ii) vulcanization accelerator tetramethylthiuram disulfide (TMTD) and (iii) organic peroxide di(2-tert-butyl-peroxyisopropyl)benzene (BIB1) were applied to enhance reclaiming of GTR. Reclaiming process was evaluated by oscillating...
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Characterization of volatile compounds, structural, thermal and physico-mechanical properties of cross-linked polyethylene foams degraded thermo-mechanically at variable times
PublikacjaWaste cross-linked polyethylene foam (wXLPE) was thermo-mechanically degraded at variable time using internal batch mixer. The progress of wXLPE degradation has been investigated by using a simultaneous thermogravimetric/differential scanning calorimetry analyzer coupled with Fourier transform infrared spectroscopy, swelling measurements, tensile tests and scanning electron microscopy. Volatile organic compounds generated during...
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Rheological characteristics of oligomeric semiproducts gained via chemical degradation of polyurethane foam using crude glycerin in the presence of different catalysts
PublikacjaPolyurethane (PU) recycling is a topic of growing interest due to the increasing amount of polyurethane waste. The main purpose of polyurethane chemical recycling is to recover the starting polyol. In this study, a method of polyurethane thermochemical recycling, glycerolysis by means of crude glycerin, is proposed. This work presents a comparative study of commercial catalysts used in order to accelerate the decomposition process,...
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Synthesis and characterisation of polyurethane elastomers with semi-products obtained from polyurethane recycling
PublikacjaIn this work polyurethane elastomers were synthesised by using different mixtures of a petrochemical and glycerolysate polyols and 4,4-diphenylmethane diisocyanate (MDI). Glycerolysate polyol was produced from polyurethane foam decomposition using crude glycerine as a decomposition agent. The structure and thermal properties of obtained semi-product were similar to the polyol used in the synthesis of original foam. Glycerolysate...
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A comparative study on selective properties of Kraft lignin–natural rubber composites containing different plasticizers
PublikacjaEffect of plasticizer type on the kraft lignin–nat- ural rubber composite microstructure and selected proper- ties was determined. The composites were prepared with addition of a commonly used naphthenic oil plasticizer to study the decomposition product of polyurethane (glyc- erolysate) and its characteristics. Kraft lignin powder was incorporated into the natural rubber matrix in amounts of 10 and 40 parts per 100 parts of natural...