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Wyniki wyszukiwania dla: POLYMER DERIVED CERAMICS
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RESEARCH ON HYDRODYNAMIC PEEK JOURNAL BEARINGS LUBRICATED WITH WATER AND OIL
PublikacjaThe main purpose of the research was to determine the possibilities and experimentally test the benefits of replacing conventional oil lubrication with ecological water lubrication. Tests were carried out on a test rig for hydrodynamic radial bearings under conditions representative of the expected applications for the bearing in water turbines. Bearings made from the polymer material PEEK (polyether ether ketone) were tested under static...
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Assessment of Tensile Strength Reserve of Asphalt Mixtures at Low Temperatures
PublikacjaDuring winter conditions, low-temperature cracks develop at the surface of the asphalt pavement when tensile thermal stress induced in the asphalt layer during cooling equals and exceeds the tensile strength of the material. The paper presents the results of tensile strength reserve assessment of asphalt mixtures with neat and SBS-polymer modified bitumen application. The tensile strength reservewas calculated as difference between...
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Reviewing the recent developments of using graphene-based nanosized materials in membrane separations
PublikacjaAccording to the potentialities of graphene-based materials and their unique physicochemical properties. Such 2D nanomaterials are likely to be the most implemented within the improvement of the selective separations of polymer membranes, together with enhanced physicochemical properties (such as hydrophilicity/hydrophobicity, transport of molecules, mechanical and thermal features, among others). Hence, this review compiles and...
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Production of trehalose in a single step enzymatic reaction
PublikacjaThe aim of this study was isolation and cloning of trehalose synthase gene derived from extremophilic microorganisms Deinoccoci to the expressive E. coli vectors and its biosythesis in different hosts.
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Biodegradable polymers for food packaging - factors influencing their degradation and certification types - a comprehensive review
PublikacjaIn the paper an overview of novel biodegradable polymers for food packaging can be found. The aim was to present factors influencing polymer degradation and biodegradation in various environments. It was noted that biodegradable polymers are imperfect alternative for classical polymers and its decomposition strongly depends on degradation environment.
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Vertical vibration reduction and audible sound analysis in surface grinding with electroplated tools
PublikacjaOne of the first approaches to the development of a grinding process monitoring system based on audible sound sensors is presented in the paper. Electroplated diamond tools (abrasive D64 and D107) were used in a modified single-disc lapping machine configuration for flat grinding of ceramics (Al2O3). The main aim of the machine modification was to reduce the vertical vibration in order to decrease the tool wear and to increase...
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Stability of softly switched multiregional dynamic output controllers with a static antiwindup filter: A discrete-time case
PublikacjaThis paper addresses the problem of model-based global stability analysis of discrete-time Takagi–Sugeno multiregional dynamic output controllers with static antiwindup filters. The presented analyses are reduced to the problem of a feasibility study of the Linear Matrix Inequalities (LMIs), derived based on Lyapunov stability theory. Two sets of LMIs are considered candidate derived from the classical common quadratic Lyapunov...
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PREPARATION AND CHARACTERIZATION OF CoFe2O4/TiO2-PANI HYBRID NANOCOMPOSITE WITH MAGNETIC AND PHOYOCATALYTIC ACTIVITY
PublikacjaHybrid nanocomposites consisting of inorganic component and organic conducting polymer are promising materials, which can be applied in heterogeneous photocatalysis. Titanium(IV) oxide is widely used photocatalysts due to its non-toxicity, low cost and chemical stability. The main disadvantage of TiO2 is low photocatalytic activity under visible light. Conducting polymers, also known as conjugated polymers are polymer materials...
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iPP/HDPE blends compatibilized by a polyester: An unconventional concept to valuable products
PublikacjaPolyolefins are the most widely used plastics accounting for a large fraction of the polymer waste stream. Although reusing polyolefins seems to be a logical choice, their recycling level remains disappointingly low. This is mainly due to the lack of large-scale availability of efficient and inexpensive compatibilizers for mixed polyolefin waste, typically consisting of high-density polyethylene (HDPE) and isotactic polypropylene...
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Permeation and sorption properties of poly(ether-block-amide) membranesfilled by two types of zeolites
PublikacjaThe experimental study of transport properties of mixed matrix membranes (MMMs) based on PEBA-4033 with two types of zeolites is reported. Gas (CO2, O2, N2) and vapor (benzene, toluene, methanol, water) permeation measurements were performed using the differential flow permeameter at temperature of 298.15 K and at atmospheric pressure. Gas/vapor permeation was monitored by measuring the changes of the thermal conductivity of carrier...
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Local properties of organic coatings close to glass transition temperature
PublikacjaAcrylic coating applied on copper substrate has been investigated at different temperatures starting from the ambient one up to the level above the glass transition temperature. Its local topographic and electric properties have been examined with the atomic force microscopy (AFM) based approach including dc current mapping and local impedance spectroscopy. The local findings have been compared with the information from global...
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Dynamic tests of composite footbridge segment – experimental and numerical studies
PublikacjaExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
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Polyurethanes
PublikacjaHandbook of Thermoset Plastics, Fourth Edition provides complete coverage of the chemical processes, manufacturing techniques and design properties of each polymer, along with its applications. This new edition has been expanded to include the latest developments in the field, with new chapters on radiation curing, biological adhesives, vitrimers, and 3D printing. This detailed handbook considers the practical implications of using...
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Data regarding a new, vector-enzymatic DNA fragment amplification-expression technology for the construction of artificial, concatemeric DNA, RNA and proteins, as well as biological effects of selected polypeptides obtained using this method
PublikacjaApplications of bioactive peptides and polypeptides are emerging in areas such as drug development and drug delivery systems. These compounds are bioactive, biocompatible and represent a wide range of chemical properties, enabling further adjustments of obtained biomaterials. However, delivering large quantities of peptide derivatives is still challenging. Several methods have been developed for the production of concatemers –...
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Torsion of restrained thin-walled bars of open constant bisymmetric cross-section
PublikacjaElastic and geometric stiffness matrices were derived using Castigliano's first theorem, for the case of torsion of restrained thin-walled bars of open constant bisymmetric cross-section. Functions which describe the angles of torsion were adopted from the solutions of thedifferential equation for restrained torsion. The exact solutions were simplified by expanding them in a power series. Numerical examples were taken from Kujawa...
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Correlation between structural and electrical properties in highly porous (Y,Sr)(Ti,Nb)O3-delta SOFC anodes
PublikacjaIn order to find a relationship between structural and electrical properties, niobium and yttrium doped SrTiO3 ceramics were prepared via solid-state reaction. The samples were sintered in hydrogen and air conditions. The samples were also fabricated with a pore-former to obtain highly porous specimens. The electrical properties of Nb-doped SrTiO3 samples and yttrium and niobium co-doped SrTiO3 were compared. The comparable electrical...
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ALTERNATIVE, DIRECT SYNTHESIS METHOD OF THE CERAMIC SOLID SOLUTIONS BASED ON BaTiO3 THROUGH A HIGH ENERGY BALL MILLING
PublikacjaPolycrystalline samples BaTiO3 and the solid solutions Ba0.9Sr0.1TiO3, Ba0.9Sr0.1Ti0.9Sn0.1O3, Ba0.9Sr0.1Ti0.8Sn0.2O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure...
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Core-Shell Nanoparticles with Hyperbranched Poly(arylene-oxindole) Interiors
PublikacjaCore-shell type star polymers composed of poly(tert-butyl acrylate) (poly(t-BuA)) arms and 100% hyperbranched poly(arylene-oxindole) interiors were synthesized via the "core-first" method. Atom transfer radical polymerization of t-BuA initiated by 2-bromopropionyl terminal groups of the hyperbranched core was applied for the synthesis of the stars. The resultant star structures were characterized by gel permeation chromatography...
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Synthesis and characterization of novel renewable polyesters based on 2,5-furandicarboxylic acid and 2,3-butanediol
PublikacjaNovel polyesters from 2,5-furandicarboxylic acid or 2,5-dimethyl-furandicarboxylate and 2,3-butanediol have been synthesized via bulk polycondensation catalyzed by titanium (IV) n-butoxide, tin (IV) ethylhexanoate, or zirconium (IV) butoxide. The polymers were analyzed by size exclusion chromatography, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy (FTIR), matrix-assisted laser ionization-desorption...
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Functionalization of Parylene During Its Chemical Vapor Deposition
PublikacjaTwo possible mechanisms for the reaction of four halogenated (metha)acrylate-based molecules with Parylene [poly (paraxylylene)] during its chemical vapor deposition were proposed. The chemical reactivity of acrylate double bond with the paraxylylene biradical was calculated for all four (metha)acrylate-based molecules. These calculations allowed the evaluation of the energetically favorable mechanism and indeed a direct correlation...
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Comparison of disk and tube methods for estimation of biostatic properties of polyurethanes based on synthetic poly[(R,S)-3-hydroxybutyrate
PublikacjaThe influence of novel aliphatic polyurethanes on growth of Staphyloccocus aureus (SA)in the around of polymer samples has been estimated by disk method. It was staed that the growth of SA was inhibited.The influence of polyurethanes on planctonic Staphyloccocus aureus was also pefrormed by tube method. In this test the slight decrease of bacteria concentration was noticed.
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Determination of amikacin and ciprofloxacin by liquid chromatography with pre-column derivatization to evaluate sustained delivery of antibiotics from Drug-Eluting Biopsy Needle
PublikacjaDetermination of chosen antibacterial antibiotics: amikacin and ciprofloxacin was carried out by HPLC-UV after derivatization with 9-fluorenylmethyl chloroformate and in their native form by HPLC-MS/MS. Developed methods have been applied to control the kinetics of antibiotic release from polymer-based controlled drug delivery system.
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INVESTIGATION OF SOUR SUBSTANCES BY FIVE-CHANNEL POTENTIOMETRIC TASTE SENSOR CONTAINING ALL-SOLID-STATE- ELECTRODES (ASSEs)
PublikacjaAn elaboration of taste sensor for discrimination of different food products is of great importance for food industry. Potentiometric taste sensor containing ion selective electrodes with lipid/polymer membranes has already been applied commercially in food industry. However, time-consuming and demanding preconditioning method of ions selective electrodes as well as maintenance of electrodes’ bodies are disadvantages of this taste...
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Investigation of sour substances by five-channel potentiometric taste sensor containing all-solid-state-electrodes ( ASSEs)
PublikacjaAn elaboration of taste sensor for discrimination of different food products is of great importance for food industry. Potentiometric taste sensor containing ion selective electrodes with lipid/polymer membranes has already been applied commercially in food industry. However, time-consuming and demanding preconditioning method of ions selective electrodes as well as maintenance of electrodes’ bodies are disadvantages of this taste...
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A study on fibre-reinforced concrete elements properties based on the case of habitat modules in the underwater sills
PublikacjaHydrotechnical constructions are mostly objects functioning in extreme conditions and requiring a custom-made construction project. In the case of using prefabricated elements, it is required to develop production, transport, assembly, conservation and repair technology. Concerning the problem of concrete cracks, modern repair systems allow positive effects to be achieved in many cases of concrete elements repair. In this work...
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Low-Temperature Requirements for Bitumen in Central East European Road Construction
PublikacjaThe paper presents the proposition of special assessment of lowtemperature requirements for bitumens in the region of Central and Eastern Europe where there is a moderate transitional area from sea to the continental type of climate. The results of the research program conducted on the road neat bitumens, Styrene-Butadiene-Styrene polymer and polymer-rubber modified bitumen, and multigrade bitumen types were presented and discussed....
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Removal of nonsteroidal anti-inflammatory drugs and analgesics from wastewater by adsorption on cross-linked β-cyclodextrin
PublikacjaWe present a method using the material in the form of cross-linked β-cyclodextrin (CD) showing high efficiency in the simultaneous removal of hazardous pollutants from sewage, such as diclofenac (DIC), ibuprofen (IBU), ketoprofen (KETO), naproxen (NAPR), salicylic acid (SALI) and tramadol (TRAM). The material is stable and particularly easy to regenerate. The sorbent probably remembers the shape of the contaminants, which increases...
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Progress in used tyres management in the european union: a review
PublikacjaThe dynamic increase in the manufacture of rubber products, particularly those used in the automobile industry, is responsible for a vast amount of wastes, mostly in the form of used tyres, of which more than 17 million tonnes are produced globally each year. The widely differing chemical compositions and the cross-linked structures of rubber in tyres are the prime reason why they are highly resistant to biodegradation, photochemical...
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Chemical modifications of graphene and their influence on properties of polyurethane composites: a review
PublikacjaPolyurethane composites are materials of great interest nowadays due to their wide range of available forms and applications in industry. Controlling and achieving unique properties via matrix modifications and addition of various specific nanofillers seems be one of the key elements to success. The purpose of this work is to briefly present some examples of graphene nanoderivatives, their syntheses, properties and influence on...
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Study of the NO2 sensing mechanism of PEDOT-RGO film using in situ Raman Spectroscopy
PublikacjaIn this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4− (PEDOT/ClO4−) films were fabricated using an electrodeposition method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate...
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An influence of molecular weight, deacetylation degree of chitosan xerogels on their antimicrobial activity and cytotoxicity. Comparison of chitosan materials obtained using lactic acid and CO2 saturation.
PublikacjaThis paper presents a comparison of the antimicrobial activity and cytotoxicity against L929 cells of chitosan xerogels prepared by dissolving the polymer in a solution of lactic acid (LA) or carbonic acid (CO2) and then freeze-drying. There was no simple relationship between the antimicrobial activity and cytotoxicity of the samples obtained using both techniques (LA and CO2). Chitosan materials obtained by the LA method in a...
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Investigation of Wood Flour Size, Aspect Ratios, and Injection Molding Temperature on Mechanical Properties of Wood Flour/Polyethylene Composites
PublikacjaIn the present research, wood flour reinforced polyethylene polymer composites with a coupling agent were prepared by injection molding. The effects of wood flour size, aspect ratios, and mold injection temperature on the composites’ mechanical properties were investigated. For the preparation of the polymer composites, five different formulations were created. The mechanical properties including tensile strength and the modulus,...
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Coatings in arthroplasty [online]
PublikacjaThe modern coatings used in arthroplasty for long term implants are reviewed. The phosphate coatingsare the most popular technique to improve the bone-implant interfacial strength and promote theosseointegration. The plasma spraying, electrophoretic precipitation, powder metallurgy, ion beamsputtering, high velocity oxy-fuel (HVOF) combustion spraying, sol-gel technique, biomimeticdeposition are mostly used to obtain the phosphate,...
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Evaluation of adhesive forces and the specific surface energy of zirconia stabilized by yttria with alumina additions ceramic by AFM method
PublikacjaThe adhesive forces and the specific surface energy of ceramic material surfaces are very important for further tribological and biomedical applications of ceramics. Partially stabilized zirconia (zirconium oxide) is popular for manufacturing various medical products. ZrO2 stabilized by Y2O3 with additions of 5 wt% alumina was produced by slip casting method with a subsequent sintering. Structure and chemical composition of ceramic...
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KTaO3 a perovskite for water and air treatment
PublikacjaPerovskites are inorganic compounds that exhibit dielectric properties. These minerals belong to the crystal ceramics family. These compounds are described by the formula: ABX3 where, A and B are 2, 3 or 4 valuable metal ions, and X is an ion of oxygen or fluorine. An example of perovskite is the compound KTaO3. There are many methods for producing KTaO3, but the hydrothermal method is most commonly used. Perovskites can be characterized...
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Buckling of thin-walled columns accounting for initial geometrical imperfections
PublikacjaThe paper is devoted to the effect of some geometrical imperfections on the critical buckling load of axially compressed thin-walled I-columns. The analytical formulas for the critical torsional and flexural buckling loads accounting for the initial curvature of the column axis or the twist angle respectively are derived. The classical assumptions of theory of thin-walled beams with non-deformable cross-sections are adopted. The...
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Influence of the internal electrolyte composition on amperometric sulphur dioxide sensor properties
PublikacjaIn this work amperometric sulphur dioxide sensor with a liquid electrolyte, a mercury sulphate reference electrode and solid polymer electrolyte (Nafion) covered with gold as a working electrode will be presented. The main goal of this research is to determine the influence of internal electrolyte composition on the sensor properties. Sensor filled with 1M and 5M sulphuric acid has been investigated.
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A solution of non-linear differential problem with application to selected geotechnical problems
PublikacjaA certain non-linear differential equation containing a power of unknown function being the solution is considered with application to selected geotechnical problems. The equation can be derived to a linear differential equation by a proper substitution and properties of the operations G and S.
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Aluminium in glacial meltwater demonstrates an association with nutrient export (Werenskiöldbreen, Svalbard)
PublikacjaThe aluminium (Al) cycle in glacierised basins has not received a great deal of attention in studies of biogeochemical cycles. As Almay be toxic for biota, it is important to investigate the processes leading to its release into the environment. It has not yet been ascertained whether filterable Al (passing through a pore size of 0.45 m) is incorporated into biogeochemical cycles in glacierised basins. Our study aims to determine...
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Relatively high-Seebeck thermoelectric cells containing ionic liquids supplemented by cobalt redox couple
PublikacjaMeanwhile no general and reliable equation determining the Seebeck coefficient (S e ) and involving electro-chemical reaction effects was derived for solutions. We reported the database of 15,000 ionic liquids supplemented by three different redox couple systems: 0.01 mol/l Co 3+/2+ (bpy) 3 , 0.01 mol/l I 3-/3I- and 0.2 mol/l 3- /3I- , and the corresponding estimated Seebeck coefficients. We also reported methods for estimating...
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Badania eksperymentalne rezonansowego przetwornika piezoelektrycznego typu "unimorph"
PublikacjaW artykule opisano badania eksperymentalne piezoelektrycznego rezonansowego przetwornika zastosowanego do pomiaru właściwości mechanicznych tkanek miękkich. Po krótkim wstępie w kolejnych punktach przedstawiono opis stanowiska pomiarowego oraz metody pomiaru odkształceń prototypów, przesunięć częstotliwości rezonansowej, impedancji elektromechanicznej i parametrów schematów zastępczych. W dalszej...
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Influence of the internal electrolyte composition on amperometric sulphur dioxide sensor properties
PublikacjaIn this work investigation of an amperometric sulphur dioxide sensor with a liquid electrolyte, a mercury sulphate reference electrode and solid polymer electrolyte (Nafion) covered with gold as a working electrode properties is presented. The main goal of this research is to determine the influence of internal electrolyte composition on the sensor properties. Sensor filled with 1M and 5M sulphuric acid has been studied.
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Renewable natural resources as green alternative substrates to obtain bio-based non-isocyanate polyurethanes-review
PublikacjaCommercially available polyurethanes are synthesized by the polyaddition of diisocyanates with polyols and low molecular weight chain extenders. A new approach to polyurethanes synthesis is realized via non-isocyanate routes. Negative impacts of petroleum-based chemicals on the environment and human health as well as gradual reduction of fuel-based resources, which leads to an increase in their prices, are an incentive to looking...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublikacjaThe paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described...
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Analytical Expression for the Time-Domain Green's Function of a Discrete Plane Wave Propagating in the 3-D FDTD Grid
PublikacjaIn this paper, a closed-form expression for the time-domain dyadic Green’s function of a discrete plane wave (DPW) propagating in a 3-D finite-difference time-domain (FDTD) grid is derived. In order to verify our findings, the time-domain implementation of the DPW-injection technique is developed with the use of the derived expression for 3-D total-field/scattered-field (TFSF) FDTD simulations. This implementation requires computations...
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High-density Polyethylene - Expanded Perlite Composites: Structural Oriented Analysis of Mechanical and Thermomechanical Properties
PublikacjaAs part of this work, research was carried out on the effect of the addition of expanded perlite (PR) on the mechanical and thermomechanical properties of high-density polyethylene (PE) composites. Composites containing from 1 to 10 wt% of the inorganic filler were produced. Polyethylene-based composites manufactured by twin-screw extrusion and formed in the compression molding process were subjected to mechanical, thermomechanical,...
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Monitoring of crosslinking of a DGEBA-PAMAM adhesive in composite/aluminium bonded joint using mechanical and ultra-sound techniques
PublikacjaAdhesive cure is an important and determining aspect of strength and stability of bonded structures. Crosslinking of the polymer leads to the adhesive strength, stiffness and durability. Depending on the resin and curing agent used, cure time can vary from minutes to weeks, even then 100% crosslinking not being guaranteed. Standard methods based on dynamic mechanical analysis (DMA) or calorimetric techniques (DSC, DTA) are valuable...
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In-Situ Processing of Biocomposites via Reactive Extrusion
PublikacjaLaw regulations, economic and environmental factors are the main causes for the rapidly growing interests in biocomposites’ research, conducted currently in a number of academic and industrial scientific centers. However, weak polymer matrix/filler interactions, common in biocomposites, result in unsatisfactory mechanical properties, which limit their practical applications. From many attempts performed to solve this problem, in-situ...
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Waste tire rubber as low-cost and environmentally-friendly modifier in thermoset polymers – a review
PublikacjaNowadays, waste tire rubber (WTR) management is a growing and serious problem. Therefore, research works focused on the development of cost-effective and environmentally-friendly methods of WTR recycling are fully justified. Incorporation of WTR into polymer matrices and composite materials attracts much attention, because this approach allows sustainable development of industrially applicable waste tires recycling technologies....
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Experimental Studies of Concrete-Filled Composite Tubes under Axial Short- and Long-Term Loads
PublikacjaThe paper presents experimental studies on axially compressed columns made of concrete-filled glass fiber reinforced polymer (GFRP) tubes. The infill concrete was C30/37 according to Eurocode 2. The investigated composite pipes were characterized by different angles of fiber winding in relation to the longitudinal axis of the element: 20, 55 and 85 degrees. Columns of two lengths, 0.4 m and 2.0 m, were studied. The internal diameter...