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Search results for: BLADDER ACELLULAR MATRIX
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Fabrication of exfoliated graphite reinforced silicone rubber composites - Mechanical, tribological and dielectric properties
PublicationThe effect of exfoliated graphite (EG) on the mechanical, tribological and dielectric properties of the silicone rubber (QM) composites has been systematically investigated and analysed. Morphological analysis of the composites helps to understand the interfacial interaction between the filler and the rubber matrix as well as wear mechanism respectively. An enhancement in the mechanical, tribological and dielectric properties was...
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Fabrication of exfoliated graphite reinforced silicone rubber composites - Mechanical, tribological and dielectric properties
PublicationThe effect of exfoliated graphite (EG) on the mechanical, tribological and dielectric properties of the silicone rubber (QM) composites has been systematically investigated and analysed. Morphological analysis of the composites helps to understand the interfacial interaction between the filler and the rubber matrix as well as wear mechanism respectively. An enhancement in the mechanical, tribological and dielectric properties was...
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AN ORIGINAL APPROACH IN THE FIELD OF PREPARATION REFERENCE MATERIALS OF VOLATILE ANALYTES
PublicationStandard gas mixtures (SGM) are indispensable reference materials for ensuring the reliability of analytical work. Reference materials are an excellent tool for the quality control and assurance of analytical results. Standard gas mixtures are unique among reference materials. The rapid progress of SGM production is connected with the instability of gaseous analytes which make them difficult to obtain. The use of standards with...
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Dyskretno-ciągła metoda modelowania układów dynamicznych
PublicationW artykule przedstawiono oryginalną metodę modelowania układów dyskretno-ciągłych. Metoda polega na dyskretyzowaniu układu trójwymiarowego jedynie w dwóch wybranych kierunkach. W trzecim z kierunków układ pozostaje ciągły. Otrzymany w ten sposób model jest modelem dyskretno-ciągłym. Opisany jest za pomocą równań różniczkowych cząstkowych. Ogólne równania różnicowe układu dyskretnego otrzymano, wykorzystując metodę sztywnych elementów...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
Open Research DataThe attached data contains the results of measurements of phosphate glasses and glass-ceramics doped with Eu. On their basis, the new material was characterized and the influence of the SrF2 addition on the glass structure was determined. In addition, the influence of the SrF2 content and controlled crystallization on the luminescent properties of Eu3+...
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The modelling method of discrete-continuous systems
PublicationThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...
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Chitosan, Collagen and Gelatin in the design of novel materials with antimicrobial acticity
PublicationMedical devices containing and releasing antiinfective agents directly on the site of injury are a common group of materials available and widely used in treating difficult to heal wounds. Sustained contact of the active agent to the damaged tissue, needed to inhibit infection and preservation of microbiological purity of the wound, is provided by the immobilization antimicrobial agents on the surface of the matrix material or...
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Morphology of bio-based polyurethane composites filled by mer-cerized or silanized natural fibres
PublicationBio-composites are materials which possess unique properties and undergo biodegra-dation under specific conditions. Bio-composites belong to the group of materials produced with the use of renewable raw materials. They contain reinforcement, mainly in the form of natural fiber, which has high stiffness and resistance; filler powders are less frequently used. Significant features of natural fibers are elongation, density, thermal...
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An Analog Sub-Miliwatt CMOS Image Sensor With Pixel-Level Convolution Processing
PublicationA new approach to an analog ultra-low power medium-resolution vision chip design is presented. The prototype chip performs low-level image processing algorithms in real time. Only a photo-diode, MOS switches and two capacitors are used to create an analog processing element (APE) that is able to realize any convolution algorithm based on a full 3x3 kernel. The proof-of-concept circuit is implemented in 0.35 µm CMOS technology,...
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Extending touch-less interaction with smart glasses by implementing EMG module
PublicationIn this paper we propose to use temporal muscle contraction to perform certain actions. Method: The set of muscle contractions corresponding to one of three actions including “single-click”, “double-click” “click-n-hold” and “non-action” were recorded. After recording certain amount of signals, the set of five parameters was calculated. These parameters served as an input matrix for the neural network. Two-layer feedforward neural...
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APPLICATION OF QUANTITATIVE RISK ASSESSMENT TO SHIPS IN EMERGENCY CONDITIONS
PublicationThe paper is devoted to safety of ships in emergency conditions. The currently valid prescriptive method of safety assessment of ships in damage conditions is included in the SOLAS 2009 Part B-2 Ch.II-1 regulations. It is devoted to the design stage and difficult to apply in operation. A possible alternative described in this paper is a method based on assessment of performance of ships and risk assessment. Type of risk evaluation...
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Mesoscopic simulations of crack propagation in concrete using cohesive elements
PublicationThe paper presents results of two-and three-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 3-phase material composed of aggregate grains placed in the cement matrix with Interfacial Transitional Zones (ITZs) between then. In 2D simulations macro-voids were also taken into account. The particle distribution was taken from real concrete beams...
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Bio polyetherurethane composites with high content of natural ingredients: hydroxylated soybean oil based polyol, bio glycol and microcrystalline cellulose
PublicationIn our study, we focused on obtaining bio-polyurethane composites using bio-components such as bio glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The pre-polymer method was used to prepare the bio polyurethane matrix. Prepolymer was synthesized using 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 50 wt.% of commercial polyether and 50 wt.% of hydroxylated soybean oil (H3)....
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Influence of selected submicron inorganic particles on mechanical and thermo-mechanical properties of unsaturated polyester/glass composites
PublicationIn this paper, the influence of different submicron-scaled particles (zinc oxide, titanium dioxide, or silica) on mechanical and thermo-mechanical properties of unsaturated polyester matrix composites reinforced with glass fabric was investigated. Surface morphology of obtained composites was also examined. At first inorganic particles were mechanically dispersed into unsaturated polyester resin system as per the calculated weight...
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Application of the numerical-analytic method for systems of differential equations with parameter
PublicationThe numerical-analytic method is applied to systems of differential equations with parameter under the assumption that the corresponding functions satisfy the Lipschitz conditions in matrix notation. We also obtain several existence results for problems with deviations of an argument
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Próba uogólnionej oceny efektywności wybranych rynków pracy
PublicationCelem artykułu jest pilotażowa próba dokonania uzupełnienia oceny efektywności rynków pracy wynikami uprzednio przeprowadzonej analizy mobilności międzysektorowej płac oraz zatrudnienia. Ocena mobilności międzysektorowej przeprowadzona zostanie dwutorowo: z jednej strony za pomocą uzupełnienia jej o zobrazowanie reakcji rynków na międzysektorowe przesunięcia zatrudnienia, a z drugiej z użyciem ocen zagregowanej zmiany zróżnicowania...
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Structure, morphology and mechanical behaviour of novel bio-based polyurethane composites with microcrystalline cellulose
PublicationThe aim of this work was to obtain bio-based polyurethane composites using biocomponents such as, bio-glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The prepolymer method was used to prepare the bio-based polyurethane matrix. Prepolymer synthesised from 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% wt. commercial polyether and 25% wt. hydroxylated soybean oils (H3)...
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Nanosize effect of clay mineral nanoparticles on the drug diffusion processes in polyurethane nanocomposite hydrogels
PublicationStudies of swelling and release of naproxen sodium (NAP) solution by polyurethane nanocomposite hydrogels containing Cloisite® 30B (organically modified montmorillonite (OMMT)) have been performed. Polyurethane nanocomposite hydrogels are hybrid, nontoxic biomaterials with unique swelling and release properties in comparison with unmodified hydrogels. These features enable to use nanocomposite hydrogels as a modern wound dressing....
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Zero-range potentials for Dirac particles: Bound-state problems
PublicationA model in which a massive Dirac particle in $\mathbb{R}^{3}$ is bound by $N\geqslant1$ spatially distributed zero-range potentials is presented. Interactions between the particle and the potentials are modeled by subjecting a particle's bispinor wave function to certain limiting conditions at the potential centers. Each of these conditions is parametrized by a $2\times2$ Hermitian matrix (or, equivalently, a real scalar and a...
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Helium-assisted, solvent-free electro-activation of 3D printed conductive carbon-polylactide electrodes
PublicationFused filament fabrication is one of the most rapidly developing 3D printing techniques, with numerous applications, including in the field of applied electrochemistry. Here, the utilisation of conductive carbon black polylactic acid (CB-PLA) for 3D printouts is the most promising. To use CB-PLA as an electrode material, an activation process must be performed, removing the polymer matrix and uncovering the electrically conductive...
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Chemical structure, thermal and mechanical characterization of bio-based polyurethane composites filled with microcrystalline cellulose
PublicationOver the past several decades, the interest in replacing the synthetic components used in the production of polymers and composites with their natural counteparts has been growing. Biocomposites belong to the group of materials produced with the use of renewable raw materials. There has been a recent surge of interest in the industrial applications of composites containing natural fibres reinforced with biopolymers. Biopolymers...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublicationThe 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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Mixed ionic-electronic conductivity and structural properties of strontium-borate glass containing nanocrystallites of Bi2 VO5.5
PublicationSamples of strontium borate glass containing bismuth vanadate nanocrystallites were prepared. Nanocomposites containing up to 45mol% of the Bi2VO5.5 phase exhibit electrical properties closer to the strontium-borate glass than to the ferroelectric Bi2VO5.5 ceramic. The glass matrix still may contain some part of bismuth and vanadium ions even after crystallization process and there is too little of crystalline phase to observe...
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Recent advances in compatibilization strategies of wood-polymer composites by isocyanates
PublicationWood-polymer composites technologies are gaining more and more attention in the scientific community, positively affecting the increase in their industrial applications, for example, automotive, building, 3D printing, etc. Many research works are focused on the improvement in matrix–lignocellulosic filler interactions to produce highly filled composites with satisfying performance properties. In this field of research, using isocyanates...
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Low energy inelastic electron scattering from carbon monoxide: I. excitation of the a3Π, a’3Σ+ and AΠ1 electronic states.
PublicationDifferential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20◦ to 120◦. The normalization of the experimental cross sections...
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Zr‐Based Metal‐Organic Framework UiO‐66/Ultem® 1000 Membranes for Effective CO2/H2 Separation
PublicationMixed-matrix membranes (MMMs) using UiO-66 nanofillers as dispersing inorganic phase and polyetherimide (PEI) as continuous polymeric matrix were synthesized. Different UiO-66 loadings of 10, 20, and 30 wt % were applied. The morphology and UiO-66 dispersion over the prepared MMMs were examined. Gas separation measurements were performed for H2/CO2 gas mixture to evaluate the influence of UiO-66 on the separation yield of resulting...
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Differential Quadrature Method for Dynamic Buckling of Graphene Sheet Coupled by a Viscoelastic Medium Using Neperian Frequency Based on Nonlocal Elasticity Theory
PublicationIn the present study, the dynamic buckling of the graphene sheet coupled by a viscoelastic matrix was studied. In light of the simplicity of Eringen's non-local continuum theory to considering the nanoscale influences, this theory was employed. Equations of motion and boundary conditions were obtained using Mindlin plate theory by taking nonlinear strains of von Kármán and Hamilton's principle into account. On the other hand, a...
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Analiza nieliniowa powłok z materiałów gradientowych w ośrodku mikropolarnym
PublicationW 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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Effect of kenaf fibre modification on morphology and mechanical properties of thermoplastic polyurethane materials
PublicationThe presented study examined the morphology and mechanical properties of biocomposites obtained from kenaf natural fibre and thermoplastic polyurethane. Kenaf was modified using various methods, namely: acetylation, blocked isocyanate, maleic anhydride and permanganate treatment. Those methods and ways of carrying out of surface modifications were not studied before on kenaf/thermoplastic polyurethane composites. Different fibre...
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Internet photogrammetry for inspection of seaports
PublicationThis paper intends to point out the possibility of using Internet photogrammetry to construct 3D models from the images obtained by means of UAVs (Unmanned Aerial Vehicles). The solutions may be useful for the inspection of ports as to the content of cargo, transport safety or the assessment of the technical infrastructure of port and quays. The solution can be a complement to measurements made by using laser scanning and traditional...
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Preparation and characterization of natural rubber composites highly filled with brewers' spent grain/ground tire rubber hybrid reinforcement
PublicationBrewers' spent grain (BSG) and ground tire rubber (GTR) were applied as low-cost hybrid reinforcement natural rubber (NR). The impact of BSG/GTR ratio (in range: 100/0, 75/25, 50/50, 25/75 and 0/100 phr) on processing and performance properties of highly filled natural rubber composites was evaluated by oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy,...
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Curing characteristics, mechanical properties and morphology of butyl rubber filled with ground tire rubber (GTR)
PublicationThe results on testing application of ground tire rubber (GTR), as potential filler for butyl rubber, are pre- sented. The GTR content variation, within the range of 10–90 phr, was studied with respect to the vulcanization process, static mechanical properties (tensile strength, elongation-at-break, hardness and resilience), dynamic mechanical properties and the morphology of the obtained vulcanizates. Butyl rubber was characterized...
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A comparative study on selective properties of Kraft lignin–natural rubber composites containing different plasticizers
PublicationEffect 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...
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Double layer adhesive silicone dressing as a potential dermal drug delivery film in scar treatment
PublicationThe present studies focused on the evaluation of design of an adhesive silicone film intended for scar treatment. Developed silicone double layer film was examined in terms of its future relevance to therapy and applicability on the human skin considering properties which included in vitro permeability of water vapor and oxygen. In order to adapt the patches for medical use in the future there were tested such properties as...
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Evaluation and rationale of the performance of several elastomeric composites incorporating devulcanized EPDM
Publicationthylene Propylene Diene rubber (EPDM), is present in many applications. However, its crosslinked structure makes difficult its recycling. The use of devulcanized EPDM, (dEPDM) as a component of elastomeric composites, is a real possibility to reuse EPDM scraps. In this study, three matrices (natural rubber (NR), styrene butadiene rubber (SBR) and EPDM rubber) have been tested including devulcanized EPDM as a recycled component....
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URANIUM - Dyskretny świat matematyki 2022/2023
e-Learning CoursesW ramach programu URANIUM wspierania współpracy uczelni ze szkołami średnimi proponujemy takie działania jak wykłady, ćwiczenia, warsztaty komputerowe oraz konkurs matematyczny. Poniżej przedstawiam konkretny program: 1. „Wirtualny spacer po Politechnice Gdańskiej”, 2. „Matrix reaktywacja”, 3. „Układy równań – metoda Gaussa”, 4. „Równania rekurencyjne”, 5. „Matematyka dyskretna - magiczny świat podzielności liczb”, 6. „Równania...
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Numerical Issues and Approximated Models for the Diagnosis of Transmission Pipelines
PublicationThe chapter concerns numerical issues encountered when the pipeline flow process is modeled as a discrete-time state-space model. In particular, issues related to computational complexity and computability are discussed, i.e., simulation feasibility which is connected to the notions of singularity and stability of the model. These properties are critical if a diagnostic system is based on a discrete mathematical model of the flow...
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A novel method for drop in drop edible oils encapsulation with chitosan using a coaxial technique
Open Research DataThe dataset present a novel one step method for oil encapsulation. In this coaxial system the oil constitutes the core of the capsule, while the chitosan solution is the polymer shell surrounding the core to provide separation of the core from the external environment. In comparison to other encapsulation methods, the presented technique is much simpler...
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Permeation and sorption properties of poly(ether-block-amide) membranesfilled by two types of zeolites
PublicationThe 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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Grafting and reactive extrusion technologies for compatibilization of ground tyre rubber composites: Compounding, properties, and applications
PublicationChemical modification of ground tyre rubber (GTR) to compatibilize it with the matrix is a well-known approach. Based on our recent review of the surface etching methods used in GTR modification, the purpose of the current work is to take a deeper look into more advanced methods such as grafting and reactive extrusion. While grafting is more efficient in achieving compatibility, however, it usually involves multi-step synthesis...
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Graphene Reinforced Phenolic Foams
PublicationPhenolic foams (PF) belong to the polymeric materials, which are very attractive from the point of many possible applications such as insulation or fire protection materials. This chapter attempts to explain the influence of graphene and graphene derivatives on the phenolic foams. This work briefly presents different graphene nanoparticles introduced to the phenolic foams matrix, in terms of impact on the thermal, mechanical, and...
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Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings
PublicationThis article reports the design of coupled-resonatorbased microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
PublicationNew 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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Two-dimensional simulations of concrete fracture at aggregate level with cohesive elements based on X-ray lCT images
PublicationThe paper presents results of two-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 4-phase material composed of aggregate grains placed in the cement matrix, interfacial transitional zones (ITZs) and macro-voids. The particle distribution was taken from real concrete beams on the basis of X-ray lCT images. Comprehensive numerical analyses were carried...
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DEGRADATION OF GFRP MARINE LAMINATES WITH NANO PARTICLE MODIFIED COATINGS
PublicationWater absorption and surface blistering behaviour was studied for polyester-matrix laminates with SiO2 nanoparticle reinforced gel coats. Accelerated water immersion tests at 37°C showed that addition of 10% nanoparticles increases blisters incubation time by ca. 50% compared to 5% and 0% nanoparticles composites.
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Calibration images under different lighting conditions vol. 2
Open Research DataDataset description: Calibration images under different lighting conditions vol. 1
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The luminescence study of Sr2TiO4:Sm3+ coumpounds.
Open Research DataA luminescent material based on the strontium orthotitanate (Sr2TiO4) matrix doped with 1% of a mole of samarium was obtained using the typical solid-state synthesis method under a neutral atmosphere of nitrogen. The sample was investigated using powder X-ray diffraction (XRD) and several luminescence techniques to study the phase composition, luminescence...
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Calibration images under different lighting conditions - static for feature localisation
Open Research DataDataset description: Calibration images under different lighting conditions - static mode for feature detection
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Study on Dry Sliding Wear and Friction Behaviour of Al7068/Si3N4/BN Hybrid Composites
PublicationHybrid aluminium metal matrix composites have the potential to replace single reinforced aluminium metal matrix composites due to improved properties. Moreover, tribological performance is critical for these composites, as they have extensive application areas, such as the automotive, aerospace, marine and defence industries. The present work aims to establish the tribological characteristics of Al7068/Si3N4/BN hybrid metal matrix...
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Chemical modifications of graphene and their influence on properties of polyurethane composites: a review
PublicationPolyurethane 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...