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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublikacjaThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Semicrystalline Polyesters Based on a Novel Renewable Building Block
PublikacjaIsohexides, like e.g. isosorbide, are well-known carbohydrate-based rigid diols which are capable of dramatically increasing the glass transition temperature of polyesters. However, their relatively low reactivity has thus far hampered large-scale industrial applications in the polymer field. Recently, with the aim to increase reactivity while at the same time retain rigidity, we have developed a new isoidide dicarboxylic acid...
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The ILs-assisted electrochemical synthesis of TiO2 nanotubes: The effect of ionic liquids on morphology and photoactivity
PublikacjaFacile and environmentally benign one-step titanium anodization method for TiO2 nanotubes (NTs) formation in a presence of ionic liquids (ILs) was proposed. Influence of the IL structure and its content in ethylene glycol electrolyte on morphology, surface properties and photoactivity of the TiO2 NTs was investigated. Possible interactions between IL and TiO2 NTs as well as the mechanism of NTs formation during anodic oxidation...
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Determination of 3-MCPD and 2-MCPD esters in edible oils, fish oils and lipid fractions of margarines available on Polish market
Publikacja3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD) are intensively investigated food contaminants, which recently emerged as a serious problem within the discovery of high levels of their fatty acid esters in lipid samples. In order to monitor the concentrations of mentioned toxicants in edible oils and fats, several analytical methods have been developed so far. This paper presents the screening research...
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Testing the Diagnostic Utility of Recombinant Toxoplasma Gondii Chimeric Antigens – Generated Datasets
PublikacjaThe datasets titled Toxoplasma gondii recombinant chimeric antigens – IgM and IgG ELISAs – mouse serum samples and Toxoplasma gondii recombinant chimeric antigens – IgG and IgM ELISAs – human serum samples contain absorbance measurements obtained during serological tests using mouse and human sera in enzyme-linked immunosorbent assay (ELISA) tests based on recombinant chimeric antigens. The datasets allows a comparison of absorbance...
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Superconducting properties of vn-sio 2 sol-gel derived thin films
Publikacjain this work studies of structure and superconducting properties of vnsio2 films are reported. the films were obtained through thermal nitridation (ammonolysis) of solgel derived v2o3sio2 coatings (in a proper v2o3/sio2 ratio) at 1200 ◦c. this process leads to the formation of disordered structure with vn metallic grains dispersed in the insulating sio2 matrix. the structural transformations occurring in the lms as a result...
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Nano-structured Pt embedded in the acidic salts of heteropolymolybdate matrices: MS XAFS study
PublikacjaMultiple-scattering extended X-ray absorption fine structure (MS EXAFS) study combined with TEM and XRD analysis of a novel Pt-based catalyst operating at low temperature fuel cells (FCs) is presented. Innovation in the case of the considered catalyst resides in the use of a porous inorganic matrix of acidic heteropolymolybdate salts as a catalyst support. Obtained results show the relation between the matrix composition and the...
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Impedance Studies of Phosphate-iron Glasses Containing Niobium and Titanium
PublikacjaThe ac and dc conductivity in phosphate-iron-niobate glasses with addition of titanium oxide was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and confocal microscopy methods. The obtained results show that all samples are amorphous but they...
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Synthesis and biological activity of mycophenolic acid-amino acid derivatives
PublikacjaIn search of new immunosuppressants, mycophenolic acid (MPA) was coupled with amino acid methyl esters followed by hydrolysis to analogs bearing free carboxylic groups. The obtained compunds were tested in vitro as growth inhibitors of lymphoid cell line (Jurkat) and human peripheral blood mononuclear cells (PBMC) from healthy donors. According to obtained results recovering of free carboxylic group increased their activity. Additionally,...
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Analiza wydajności kolektora słonecznego przeznaczonego dla systemu ogrzewania budynku o niskim zapotrzebowaniu na ciepło
PublikacjaNiniejsza praca przedstawia wyniki badań numerycznych kolektora słonecznego, przeznaczonego dla budynków o niskim zapotrzebowaniu na ciepło. W pracy przedstawiono nowatorską koncepcję kolektora słonecznego o obniżonej wydajności, niskich kosztach wykonania oraz wykorzystującego istniejące elementy konstrukcji przekryć budynku. Istotną zaletą kolektora jest brak ingerencji w architekturę zewnętrzną budynku. Za pomocą symulacji numerycznej...
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Analiza właściwości rozszerzonego obserwatora prędkości maszyny indukcyjnej
PublikacjaRozszerzony obserwator prędkości został zaproponowany przez prof. Krzemińskiego i jest oparty na rozszerzonym modelu maszyny indukcyjnej, gdzie wprowadzona został nowa zmienna ζ. Jest to nowe podejście do estymacji zmiennych stanu maszyny indukcyjnej i nie wszystkie problemy zostały do tej pory rozwiązane. Zaproponowano wykorzystanie algorytmów ewolucyjnych do doboru wzmocnień obserwatora. W celu redukcji nakładów obliczeniowych...
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Material Identification of the Human Abdominal Wall Based On the Isogeometric Shell Model
PublikacjaThe human abdominal wall is an object of interest to the research community in the context of ventral hernia repair. Computer models require a priori knowledge of constitutive parameters in order to establish its mechanical response. In this work, the Finite Element Model Updating (FEMU) method is used to identify an heterogeneous shear modulus distribution for a human abdominal wall model, which is based on nonlinear isogeometric...
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Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
PublikacjaExperimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span...
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seafloor characterisation combined approach using multibeam sonar echo signal processing and image analysis
PublikacjaThe authors propose the approach to seafloor characterisation which relies on the combined, concurrent use of two different techniques: (i) multibeam sonar image analysis and (ii) multibeam seabed echoes processing. The first technique is based on constructing the grey-level sonar images of the seabed extracted from the echoes received in the consecutive soundings. Then, the set of parameters describing the local region of sonar...
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublikacjaThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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Study of Icosahedral Clusters in Close-packed Simple Liquids
PublikacjaThe local structure of liquid copper was determined using Steinhardt order parameters, with particular attention paid to icosahedral clusters. The positions of atoms were obtained from three sets of molecular dynamics simulations, with the forces obtained from: the Sutton-Chen (SC) potential, the Naval Research Laboratory total energy tight-binding (NRL-TB) method and the divide-and-conquer learn-on-the-fly (DCLOTF) method, respectively....
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Preparation and characterization of porous scaffolds from chitosan-collagen-gelatin composite
PublikacjaNovel porous scaffolds composed of chitosan, collagen and gelatin were prepared and characterized. For preparing scaffolds gelatin and collagen isolated from fish skins with various physicochemical properties were used. In order to reduce preparation solubility glutaraldehyde in the amount of 1%, w/w relative to the total biopolymers weight in solution was used. All obtained biomaterials showed a homogeneous porosity. Protein polymer...
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Investigation of the structural and thermal properties of aluminum-rich Ca–Al–Si–O–N glasses
PublikacjaIn this paper, we investigate the structure and thermal properties of aluminum-rich transparent Ca–Al–Si–O–N glasses. The obtained glasses were prepared by a traditional melt-quenching technique at 1650 °C using AlN as the nitrogen source. The obtained glasses have a nAl/nSi>1 and contain up to 17 eq.% of N. The structure of the glasses was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, infrared, and Raman...
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Macrocyclic derivatives of imidazole as chromoionophores for bismuth(III)/lead(II) pair
Publikacja18-membered diazomacrocycles with imidazole or 4-methylimidazole residue as a part of macrocycle were used as chromoionophores in bismuth(III) and lead(II) dual selective optodes for the first time. Cellulose triacetate membranes doped with macrocyclic chromoionophores are bismuth(III) and lead(II) selective with color change from orange/red to different shades of blue and violet, respectively. Results obtained for model and real...
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Modification of TiO2 nanotubes by graphene–strontium and cobalt molybdate perovskite for efficient hydrogen evolution reaction in acidic medium
PublikacjaHerein, we demonstrate that modification of TiO2 nanotubes with graphene–strontium and cobalt molybdate perovskite can turn them into active electrocatalysts for hydrogen evolution reaction (HER). For this purpose, a simple method of hydrothermal synthesis of perovskites was developed directly on the TiO2 nanotubes substrate. Moreover, the obtained hybrids were also decorated with graphene oxide (GO) during one-step hydrothermal...
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Comparison of Cu1.3Mn1.7O4 spinels doped with Ni or Fe and synthesized via wet chemistry and solid-state reaction methods, designed as potential coating materials for metallic interconnects
PublikacjaThe influence of the method applied to synthesize Cu-Mn-O spinel was evaluated. The methods selected for the investigation were EDTA gel processes and solid-state reaction synthesis. From the obtained powders, sinters were prepared and assessed in terms of their properties as potential coating materials. Additionally, the influence of Ni and Fe dopants was evaluated. The results show that the EDTA gel processes method seems to...
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Marek Tobiszewski dr hab. inż.
OsobyUrodzony 07.04.1984 roku w Gdańsku. W 2012 roku obronił z wyróżnieniem doktorat, w 2017 roku uzyskał habilitację na podstawie osiągnięcia naukowego „Opracowanie służących do oceny uciążliwości środowiskowej procedur analitycznych i rozpuszczalników”. Pracuje w Katedrze Chemii Analitycznej od 2012 roku. Jego zainteresowania naukowe łączą analitykę chemiczną, zwłaszcza analityka związków organicznych w próbkach środowiskowych, z...
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Study of the electrochemical stability of polypyrrole coating on iron in sodium salicylate aqueous solution
PublikacjaIn this work electrochemical stability of optimized PPy film on iron in aqueous solution of sodium salicylate is studied. The main drawback of conducting polymers is their possibility to undergo an irreversible degradation (overoxidation). The overoxidized polymers lose their properties, for example, conductivity and redox activity, what excludes them from some practical applications. This study demonstrates that lowering the concentration...
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Shaft friction from the DMT and direct shear interface tests
PublikacjaThe article presents preliminary attempt to create tri-linear transfer curves for describing pile behaviour under axial loading. Transfer curves would use the parameter measured in dilatometer test, particularly a constrained modulus MDMT. The proposed method is based on concrete rough and smooth interface tests performed in a direct shear apparatus. Based on the obtained mobilization curves, relationships were created between...
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approximation of photonic crystal fibres with large air holes by the step index fibre model
PublikacjaAn equivalent step index fibre with a silica core and air cladding is used to model photonic crystal fibres with large air holes. We model this fibre for linear polarisation (we focus on the lowest few transverse modes of the electromagnetic field). The equivalent step index radius is obtained by equating the lowest two eigenvalues of the model to those calculated numerically for the photonic crystal fibres. The step index parameters...
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Comparison of the tests for equivalence of the measurement methods for measurement of PM10 dust in ambient air
PublikacjaThe paper presents the motives for conducting the equivalence tests and the reasons of discrepancies between the results of PM10 dust concentration obtained via the reference method and the methods based on 'on-site' measurement. The reference and non-reference methods of measurement of PM10 dust concentration in air have been discussed. Field tests for equivalence, following the Polish standard and the European Union (EU) guidelines,...
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Electrohydrodynamic secondary flow and particle collection efficiency in spike-plate multi-electrode electrostatic precipitator
PublikacjaIn this work the results of electrohydrodynamic (EHD) secondary flow measurements in a spike-plate type electrostatic precipitator (ESP) are presented. In the investigated ESP two-sided and one-sided spike electrodes were used as a discharge electrodes. The results of 2D PIV measurements showed that flow pattern obtained for a different spike tips positions in respect to the primary flow direction significantly changing the flow...
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Effect of polymer fibres reinforcement on selected properties of asphalt mixtures
PublikacjaThe paper presents selected results of the research program concerning fibre reinforced asphalt concrete. Aramid-polyalphaolefin fibres was used in this study. Selected properties responsible for low temperature cracking and resistance to permanent deformation are presented in this paper. Low temperature cracking susceptibility was evaluated with the results obtained from bending test of rectangular beams with constant rate of...
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Silver complexes stabilized by large silanethiolate ligands – crystal structures and luminescence properties
PublikacjaBulky silanethiolate and disiladithiolate ligands were applied to synthesize one mononuclear and three trinuclear silver complexes including two cyclic “microclusters” and a linear tri-nuclear silanethiolate complex. All obtained compounds are characterized by X-ray diffraction and FT-IR. NMR and emission spectroscopies were used where possible. The first trinuclear anionic silver thiolate is structurally characterized. The influence...
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Fabrication, structural and electrical properties of Sr(V,Nb)O 3-δ perovskite materials
PublikacjaThe SrV1-xNbxO3-δ materials with different niobium content in perovskite B-sublattice were prepared by a solid-state reaction process. The microstructure and phase compositions of obtained samples were analyzed by the X-ray diffraction technique (XRD) and scanning electron microscopy (SEM). The electrical conductivity of samples was measured by a DC 4-wire method in range of 100–600 °C in different gas conditions. The oxidation...
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Positron binding to alkali-metal hydrides: The role of molecular vibrations
PublikacjaThe bound vibrational levels for J=0 have been computed for the series of alkali-metal hydride molecules from LiH to RbH, including NaH and KH. For all four molecules the corresponding potential-energy curves have been obtained for each isolated species and for its positron-bound complex (e+XH). It is found that the calculated positron affinity values strongly depend on the molecular vibrational state for which they are obtained...
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Emulsifi ers from renewable materials: an eco-friendly synthesis and properties
PublikacjaThe focus of this study was the preparation of novel bio based polyglycerol emulsifiers characterized by a one pot synthesis, thus by modified properties with respect to interfacial activity and effectiveness as emulsion stabilizers. The final products of the esterification process, carried out in the presence of carboxylates were used directly as emulsifiers (without purification or fractionation). Polyglycerol emulsifiers obtained...
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Simplified Map-based Selection of Optimal Spindle Speeds When Milling Complex Structures
PublikacjaIn the paper a method for selecting optimal spindle speeds for complex structures during milling operations is presented. It is based on the selection of the spindle speed in accordance with a simple equation resulting from the minimisation of vibration energy, which leads to the minimisation of the work of cut-ting forces presented in previous elaborations by the authors [1]. Optimal spindle speeds are obtained for many points...
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Efficient Finite Element Analysis of Axially Symmetrical Waveguides and Waveguide Discontinuities
PublikacjaA combination of the body-of-revolution and finite element methods is adopted for full-wave analysis of waveguides and waveguide discontinuities involving angular field variation. Such an approach is highly efficient and much more flexible than analytical techniques. The method is performed in two different cases: utilizing a generalized impedance matrix to determine the scattering parameters of a single waveguide section and utilizing...
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Graphene hydrogels with embedded metal nanopatricles as efficient catalysts in 4-nitrophenol reduction and methylene blue decolorization
PublikacjaSynthesis and characterization of the graphene hydrogels with three different metallic nanoparticles, that is Au, Ag and Cu, respectively is presented. Synthesized in a one-pot approach graphene hydrogels with embedded metallic nanoparticles were tested as heterogeneous catalysts in a model reaction of 4-nitrophenol reduction. The highest activity was obtained for graphene hydrogel with Cu NPs and additional reaction of methylene...
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A handwritten signature verification method employing a tablet
PublikacjaA signature verification system based on static features and time-domain functions of signals obtained using a tablet has been presented in the paper. The signature verification method, based mainly on dynamic time warping coupled with some signature image features, has been described. The FRR measures reflecting the method's efficiency have been evaluated for verification attempts performed directly after obtaining model signatures...
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A COMPARISON OF THE WIND SPECTRUM ACCORDING TO DIFFERENT METHODS - AN ORIGINAL PROJECT OF A BUILDING ON A CLIFF IN GDYNIA
PublikacjaThe article presents numerical simulations of the dynamic wind loads on the structure of a building designed on a cliff in Gdynia. The results obtained from the two methods: Davenport’s and Karman’s are compared. The results allowed a comparison of the two methods, and they provided an answer to the question how a construction, designed in such an unusual condition of a cliff behaves under the influence of the gusting wind. The...
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Validation of dynamic electrochemical impedance spectrograms using autocorrelation function
PublikacjaValidation of impedance data is essential for checking the reliability of experimental data. Kramers – Kronig transformation is used to verify data obtained from classical Electrochemical Impedance Spectroscopy (EIS) measurements. Data obtained from Dynamic Electrochemical Impedance Spectroscopy (DEIS) could be validated in the same way, but in this case, there is no information about internal consistency between every single spectrum...
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Metoda diagnostyki łożysk na podstawie analizy przebiegów prądu i napięcia zasilającego silnik indukcyjny.
PublikacjaW niniejszej monografii przedstawiono oryginalne podejście i realizację diagnostyki łożysk silników indukcyjnych przy użyciu metody opartej na pomiarach i analizie iloczynu wartości chwilowych prądu i napięcia zasilającego maszyny. Uzyskane wyniki badań eksperymentalnych na obiektach rzeczywistych okazały się zbieżne z wynikami badań symulacyjnych i potwierdziły, że powstanie uszkodzeń łożysk w silniku skutkuje pojawieniem się...
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Wulkanizaty kauczuku naturalnego otrzymane z użyciem plastyfikatorów pochodzenia roślinnego
PublikacjaCelem niniejszej pracy było zbadanie wpływu epoksydowanych olejów roślinnych na wybrane właściwości wul-kanizatów kauczuku naturalnego. Jako plastyfikatorów użyto epoksydowanego oleju sojowego oraz epoksydo-wanego oleju palmowego. Wpływ olejów naturalnych porównano także z wulkanizatami przygotowanymi bez użycia zmiękczaczy, jak i zawierającymi olej maszynowy, pochodzący z przerobu ropy naftowej. Zbadano wpływ rodzaju...
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Romanika Okraszewska dr inż. arch.
Osobydr inż. arch. Romanika Okraszewska jest adiunktem w Katedrze Inżynierii Drogowej i Transportowej Wydziału Inżynierii Lądowej i Środowiska Politechniki Gdańskiej. W 1996 ukończyła klasę matematyczno-informatyczną w VIII Liceum Ogólnokształcącym im. Komisji Edukacji Narodowej w Gdańsku. Absolwentka dwóch wydziałów Politechiki Gdańksiej, w roku 2002 ukończyła studia architektury i urbanistyki a w 2004 zarządzania i ekonomii. W latach...
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Modifications of total synthesis of mycophenolic acid
PublikacjaThe total synthesis of mycophenolic acid (MPA), a potent immunosuppressant, was modified. The obtained mycophenolic acid was suitable for further preparation of new prospective immunosuppressants with improved therapeutic properties.
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Polyurethane porous scaffolds (PPS) for soft tissue regenerative medicine applications
PublikacjaTissue engineering requires suitable polymeric scaffolds, which act as a physical support for regenerated tissue. A promising candidate might be polyurethane (PUR) scaffold, due to the ease of the PUR properties design, which can be adjusted directly to the intended purpose. In this study, we report a successful fabrication of porous polyurethane scaffolds (PPS) using solvent casting/particulate leaching technique combined with...
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Effect of high loading of titanium dioxide particles on the morphology and selected properties of natural rubber-based composites
PublikacjaThe aim of this work was to prepare and characterize the natural rubber vulcanizates contained different amounts of titanium dioxide particles. At first rubber mixture was prepared using a laboratory two-roll mill and then samples were vulcanized in a hydraulic press. The formulation of rubber mixture and rubber-processing technique is based on our earlier investigations. Materials were obtained at the different titanium dioxide...
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The experimental and numerical investigation of fracture behaviour in PMMA notched specimens under biaxial loading conditions – Tension with torsion
PublikacjaThis paper presents the results of experimental fracture test of flat PMMA specimens under biaxial loading condition tension with torsion (proportional). The specimens were made in two thicknesses: 5 and 15 mm and were weakened with V-type edge notches with different root radii: 0.5; 2 and 10 mm. Thanks to the ARAMIS 3D 4 M non-contact vision system, measurement of the elongation and twist angle were recorded. During experimental...
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Preparation and Properties of Thermoplastic Polyurethane Composites Filled with Powdered Buckwheat Husks
PublikacjaBio-based fillers for the polymer composites are still interesting from the scientific and industrial point of view, due to their low cost and renewable nature. In this work partially green composites were obtained by the mixing of thermoplastic poly(ester-urethane) with the unmodified and modified (by acetylation) grinded buckwheat husks. Obtained biocomposites were characterized in the terms of their chemical structure (FTIR),...
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Vibro piles performance prediction using result of CPT
PublikacjaVibro piles belong to the group of full displacement piles with an expanded base, characterised by a very high load capacity, especially in non-cohesive soils. The problem is to adopt a reliable method for the determination of full load–settlement (Q–s) curve. A frequent difficulty is the determination of the load capacity limit based on the static load test because the course of the load–settlement curve is of a linear nature....
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Rheological properties, oxidative and thermal stability, and potential application of biopolyols prepared via two-step process from crude glycerol
PublikacjaIn this work, previously synthesized biopolyols were analyzed in terms of their rheological and thermal properties, very important from the technological point of view. For better evaluation of performed synthesis, the influence of its time and temperature on the properties of biopolyols was determined. In the end, obtained materials were used to prepare rigid polyurethane-polyisocyanurate (PUR-PIR) foams, to evaluate their potential...
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Infiltration in a double-porosity medium: Experiments and comparison with a theoretical model
PublikacjaThis paper presents experimental verification of the mathematical model of unsaturated flow in double‐porosity soils developed by the asymptotic homogenization method. A series of one‐dimensional infiltration experiments was carried out in a column filled with a double‐porosity medium composed of a mixture of sand and sintered clayey spheres arranged in a periodic manner. The unsaturated hydraulic properties of each porous material...
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Study of the effect of thermally reduced graphene oxide on the physical and mechanical properties of flexible polyurethane foams
PublikacjaFlexible polyurethane foams were obtained from a two-component system via the one-step method. The foams were modified with thermally reduced graphene oxide added in the amount equal to 0.25, 0.5 and 0.75 wt%. The morphology, static and dynamic properties, and thermal stability of modified foams were determined. The application of carbon filler resulted in the visible increase in the cell size, apparent density and rigidity of...