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Search results for: adiabatical instability
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Hydrographic Multisensory Unmanned Watercraft
PublicationThis article describes the design of the unmanned surface vessel (USV) and the algorithms for planning the trajectories to be followed on measurement missions. The algorithms take account of the dynamically varying impacts of external forces (wind and surface current) on the vessel's motion. Feedback loops enable the counteraction of external factors that cause disturbance to the desired trajectory. The sensors installed on the...
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Copper and cobalt co-doped ceria as an anode catalyst for DIR-SOFCs fueled by biogas
PublicationThe nanocrystalline compounds of Co and Cu co-doped ceria (with up to 20 mol.% of dopants) were fabricated by the reverse microemulsion synthesis method. They were deposited in a form of layers on the surface of SOFC anode in an aim to act as electrochemically active materials for biogas reforming process. Fourier Transformed Infrared Spectroscopy was used to analyze a composition of outlet gases simultaneously with the tests of...
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Chromogenic azomacrocycles with imidazole residue: Structure vs. properties
PublicationNew diazo macrocycles linked by hydrocarbon chain bearing imidazole or 4-methylimidazole residue have been synthetized with satisfactory yield (24–55%). The structure of macrocycles was confirmed by X-ray analysis and spectroscopic methods (1H NMR, MS, FTIR). Metal cation complexation studies were carried out in acetonitrile and acetonitrile-water system. It was found that azomacrocyles form triple-decker complexes with lead(II)....
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Non-Adaptive Speed and Position Estimation of Doubly-Fed Induction Generator in Grid-Connected Operations
PublicationThe nonadaptive speed and position estimation scheme for a doubly-fed induction generator (DFIG) is presented in this article. The observer structure is based on the extension of the mathematical model of DFIG to the introduced H vector. Based on the defined H vector, the nonadaptive position and speed estimation is proposed. The Lyapunov method is extended to the practical stability theorem to stabilize the structure. The classic...
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Pervaporation Zeolite-Based Composite Membranes for Solvent Separations
PublicationThanks to their well-defined molecular sieving and stability, zeolites have been proposed in selective membrane separations, such as gas separation and pervaporation. For instance, the incorporation of zeolites into polymer phases to generate composite (or mixed matrix) membranes revealed important advances in pervaporation. Therefore, the goal of this review is to compile and elucidate the latest advances (over the last 2-3 years)...
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Flexomagnetic response of buckled piezomagnetic composite nanoplates
PublicationIn this paper, the equation governing the buckling of a magnetic composite plate under the influence of an in-plane one-dimensional magnetic field, assuming the concept of flexomagnetic and considering the resulting flexural force and moment, is investigated for the first time by different analytical boundary conditions. To determine the equation governing the stability of the plate, the nonlocal strain gradient theory has been...
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The effect of Sr and Mg substitutions on structure, mechanical properties and solubility of fluorapatite ceramics for biomedical applications
PublicationIonic substitutions play important role in the modifications of biological apatites. Recently, attention has been focused on the co-doping effects on the functional properties of apatite-based biomaterials. In this research work, the dense samples of fluorapatites, Ca10(PO4)6F2 and Ca8MgSr(PO4)6F2, were produced after sintering at 1250 °C for 6 h in air. Structural characterization carried out with XRD, IR, Raman and SEM, confirmed...
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MEMORY EFFECT ANALYSIS USING PIECEWISE CUBIC B-SPLINE OF TIME FRACTIONAL DIFFUSION EQUATION
PublicationThe purpose of this work is to study the memory effect analysis of Caputo–Fabrizio time fractional diffusion equation by means of cubic B-spline functions. The Caputo–Fabrizio interpretation of fractional derivative involves a non-singular kernel that permits to describe some class of material heterogeneities and the effect of memory more effectively. The proposed numerical technique relies on finite difference approach and cubic...
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MXene-based materials for removal of antibiotics and heavy metals from wastewater– a review
PublicationAs a novel family of 2D materials, MXenes provide an extensive variety of applications in water and effluent treatment due to their distinctive properties and attractive applicability, including superior electrical conductivity, higher thermal stability, hydrophilicity, and high sorption-reduction capacity. Their excellent sorption selectivity makes them perfect for removing hazardous contaminants. Currently, MXene-based materials...
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Buckling Analysis of a Micro Composite Plate with Nano Coating Based on the Modified Couple Stress Theory
PublicationThe present study investigates the buckling of a thick sandwich plate under the biaxial non-uniform compression using the modified couple stress theory with various boundary conditions. For this purpose, the top and bottom faces are orthotropic graphene sheets and for the central core the isotropic soft materials are investigated. The simplified first order shear deformation theory (S-FSDT) is employed and the governing differential...
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Exfoliated graphite with spinel oxide as an effective hybrid electrocatalyst for water splitting
PublicationThe aim of the conducted research was to develop hybrid nanostructures formed from MnCo2O4 and exfoliated graphite. Carbon added during the synthesis allowed for obtaining a well-distributed MnCo2O4 particle size with exposed active sites contributing to the increased electric conductivity. The influence of the weight ratios of carbon to a catalyst for hydrogen and oxygen evolution reactions was investigated. The new bifunctional...
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Hydrogen effects in duplex stainless steel welded joints - electrochemical studies
PublicationIn this work results on the influence of hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel (DSS) welded joints are described. The results were discussed by taking into account three different areas on the welded joint: weld metal (WM), heat-affected zone (HAZ) and parent metal. The corrosion resistance was qualified with the polarization curves registered in a synthetic sea water. The conclusion is that,...
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Physical and Thermophysical Properties of 1-Hexyl-1,4-diaza[2.2.2]bicyclooctanium Bis(trifluoromethylsulfonyl)imide Ionic Liquid
PublicationOwing to their unique properties, ionic liquids (ILs) have become a real alternative to organic compounds. Nowadays, ILs are commonly used in a number of areas such as chemical synthesis and separation techniques. However, ionic liquids continue to have a limited applicability in industry because the information on their physical and chemical properties is not readily available. This paper presents, for the first time, the results...
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Examining Quality of Hand Segmentation Based on Gaussian Mixture Models
PublicationResults of examination of various implementations of Gaussian mix-ture models are presented in the paper. Two of the implementations belonged to the Intel’s OpenCV 2.4.3 library and utilized Background Subtractor MOG and Background Subtractor MOG2 classes. The third implementation presented in the paper was created by the authors and extended Background Subtractor MOG2 with the possibility of operating on the scaled version of...
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Performance Evaluation of Asphalt Binder Modified with Shear Thickening Fluid
PublicationThis paper aims at using a dilatant or shear thickening fluid (STF) [a non-Newtonian fluid consisting of particles of nano-silica suspended in a liquid medium, i.e., ethylene glycol (EG), which acts as a carrier fluid; proportion 40:60] as additive or modifier of bitumen in order to enhance its viscoelastic properties. A commonly-used performance grading (PG) system, storage stability test, and different conventional and rheological...
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Analiza oddziaływań w kryształach związków zawierających w strukturze pierścień pirydynowy
PublicationMożliwość tworzenia się wiązań wodorowych jest kluczowym parametrem z punktu widzenia inżynierii kryształu, ponieważ wiązania wodorowe mają bezpośredni wpływ na strukturę oraz trwałość sieci krystalicznej. Głównym celem niniejszej rozprawy doktorskiej była analiza porównawcza wiązań wodorowych występujących w układach, zawierających w strukturze pierścień pirydynowy. Badane układy podzielono na: (1) układy ze związkami krzemosiarkowymi...
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Towards classification of patients based on surface EMG data of temporomandibular joint muscles using self-organising maps
PublicationThe study considers the need for an effective method of classification of patients with a temporomandibular joint disorder (TMD). The self-organising map method (SOM) was applied to group patients and used together with the cross-correlation approach to interpret the processed (rectified and smoothed by using root mean square (RMS) algorithm) surface electromyography signal (sEMG) obtained from testing the muscles (two temporal...
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PREPARATION AND CHARACTERIZATION OF CoFe2O4/TiO2-PANI HYBRID NANOCOMPOSITE WITH MAGNETIC AND PHOYOCATALYTIC ACTIVITY
PublicationHybrid 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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Influence of synthesis conditions on glass formation, structure and thermal properties in the Na 2 O-CaO-P 2 O 5 system doped with Si 3 N 4 and Mg
PublicationOxynitride phosphate glasses and glass-ceramics were prepared using new synthesis routes for phosphate glasses. Materials were melted from pre-prepared glass samples in the system Na-Ca-P-O with addition of Mg and/or Si3N4 powders under different preparation conditions. The melting process was conducted at 1000–1500 °C either under air or nitrogen atmosphere to obtain materials with different nitrogen content. Their topography...
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Conversion of waste biomass to designed and tailored activated chars with valuable properties for adsorption and electrochemical applications
PublicationWaste biomass, a renewable energy source, is inexpensive material that has great potential in sorp-tion and electrochemical application. The selected waste materials (corncobs, coconut shells, wal-nuts, and pistachio husks) allow to close the production cycle and enable material recycling, which are important aspects in the hierarchy of waste management. The proposed methodology for pro-duction and activation of biochars can be...
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A New Fuzzy Sliding Mode Controller with PID Sliding Surface for Underwater Manipulators
PublicationDesign of an accurate and robust controller is challenging topic in underwater manipulator control. This is due to hydrodynamic disturbances in underwater environment. In this paper a sliding mode control (SMC) included a PID sliding surface and fuzzy tunable gain is designed. In this proposed controller robustness property of SMC and fast response of PID are incorporated with fuzzy rules to reduce error tracking. In the control...
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Preparation and characterization of rigid polyurethane -polyglycerol nanocomposite foams
PublicationThis 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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Inhibition of amyloid fibril formation of hen egg white lysozyme by trimethylamine N-oxide at low pH
PublicationIn vitro inhibition of the formation of fibrous aggregates of proteins (amyloids) has gained increasing attention due to the number of diseases associated with protein misfolding and fibrillation. An interesting group of compounds for which pronounced activity against this phenomenon can be expected consists of low molecular weight substances (osmolytes) which have the ability to change protein stability. Here we investigate the...
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Isolation of the GFA1 gene encoding glucosamine-6-phosphate synthase of Sporothrix schenckii and its expression in Saccharomyces cerevisiae
PublicationGlucosamine-6-phosphate synthase (GlcN-6-P synthase) is an essential enzyme involved in cell wall biogenesis that has been proposed as a strategic target for antifungal chemotherapy. Here we describe the cloning and functional characterization of Sporothrix schenckii GFA1 gene which was isolated from a genomic library of the fungus. The gene encodes a predicted protein of 708 amino acids that is homologous to GlcN-6-P synthases...
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Hydrogen-enhanced degradation and oxide effects in zirconium alloys for nuclear applications
PublicationThe zirconium alloys used in nuclear industry include mainly ZreSn and ZreNb alloys ofdifferent chemical composition, microstructure and susceptibility to both hydrogendegradation and oxidation. The hypothetic nuclear accidents can create a real danger tothe Zr alloys and stability of parts made of these alloys, and especially such as loss ofcoolant accident (LOCA) and reactivity initiated accidents (RIA). The hydrogen degradationcan...
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Adsorption-assisted transport of water vapour in super-hydrophobic membranes filled with multilayer graphene platelets
PublicationThe effects of confinement of multilayer graphene platelets in hydrophobic microporous polymeric membranes are here examined. Intermolecular interactions between water vapour molecules and nanocomposite membranes are envisaged to originate assisted transport of water vapour in membrane distillation processes when a suitable filler-polymer ratio is reached. Mass transport coefficients are estimated under different working conditions,...
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Synthesis of a state feedback controller for an averaging tank with variable filling
PublicationIn paper, a nonlinear averaging tank with variable filling is considered. The main purpose of this research work was the modelling and control system synthesis of an averaging tank. The control objectives included ensuring stability and zero steady-state error of the system and achieving settling time as short as possible, while maintaining a minimal overshoot. In order to achieve the intended purpose, firstly a mathematical model...
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Electrical properties of organic and perovskite systems used in solar cells
PublicationNowadays, a great progress in the areas of molecular and hybrid photovoltaics is observed. The devices based on organic and perovskite materials are getting attention mostly due to their low cost production process. However, their efficiency and stability are still lower than for inorganic materials which make them less popular. Therefore, a detailed understanding of the device physics is fundamental for organic and perovskite...
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Robust Model Predictive Control for Autonomous Underwater Vehicle – Manipulator System with Fuzzy Compensator
PublicationThis paper proposes an improved Model Predictive Control (MPC) approach including a fuzzy compensator in order to track desired trajectories of autonomous Underwater Vehicle Manipulator Systems (UVMS). The tracking performance can be affected by robot dynamical model uncertainties and applied external disturbances. Nevertheless, the MPC as a known proficient nonlinear control approach should be improved by the uncertainty estimator...
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Influence of chemical structure on physicochemical properties and thermal decomposition of the fully bio-based poly(propylene succinate-co-butylene succinate)s
PublicationIn this work, two polyesters and four copolyesters were studied. All materials were synthesized to obtain the monomers dedicated for thermoplastic polyurethane elastomers. For this type of PUR, the monomers should characterize by appropriate selected physicochemical properties and macromolecular structure distribution, which depends on synthesis conditions. The study of chemical structure with extensive and knowledgeable analysis...
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Evaluation of the prediction ability of air pollutants based on the electronic nose responses
PublicationElectronic noses are able to perform on-line measurements of the toxic volatile compounds in air. Due to their low cost and compact size they can be placed in the areas exposed to pollution, outside the laboratory. Those advantages, on the other side, force the need for development of the reliable sensors data analysis procedures. One of the most important issues connected with electronic noses is the lack of stability of the gas...
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Novel cast polyetherurethanes based on dispersed polymeric polyols
PublicationOur study was focused on obtaining polyetherurethanes synthesized with using polymeric polyether based polyols differing in dispersed copolymer content (10, 20 and 40 wt%). The polyetherurethane materials were synthesized via two step method. The influence of different polymeric polyether based polyols on the chemical structure, morphology, mechanical and thermal properties of the obtained polyetherurethanes was investigated. The...
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Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes
PublicationRecent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O+ (uracil+ less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine...
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Measurements of flicker noise in supercapacitor cells
PublicationFlicker noise (1/f-like noise) is often used to assess the quality of various materials and devices. This phenomenon has been observed in different electrochemical devices or reactions (e.g., smart windows, pitting corrosion events). In our exploratory studies we consider how to measure and utilize 1/f noise for the quality assessment of supercapacitors. This task requires special attention because of enormous capacitance of the...
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Thermal degradation assessment of canola and olive oil using ultra-fast gas chromatography coupled with chemometrics
PublicationOil blending is often used to enhance the properties of vegetable oils. The admixture of a more thermally stable oil makes the resulting blend more suitable for use in frying. A new method of quality assessment of vegetable oils used in frying is presented in this paper. In this method, ultra-fast gas chromatography coupled with flame ionization detector and chemometrics is employed. Principal component analysis was used for data...
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New Tetragonal ReGa5(M) (M = Sn, Pb, Bi) Single Crystals Grown from Delicate Electrons Changing
PublicationSingle crystals of the new Ga-rich phases ReGa~5(Sn), ReGa~5(Pb) and ReGa~5(Bi) were successfully obtained from the flux method. The new tetragonal phases crystallize in the space group P4/mnc (No. 128) with vertex-sharing capped Re2@Ga14 oblong chains. Vacancies were discovered on the Ga4 and Ga5 sites, which can be understood as the direct inclusion of elemental Sn, Pb and Bi into the structure. Heat capacity measurements were...
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A negative effect of carbon phase on specific capacity of electrode material consisted of nanosized bismuth vanadate embedded in carbonaceous matrix
PublicationLithium-ion batteries (LIBs) are widely used all over the world. The LIBs belong to a renewable energy source and energy storage devices. The increase in energy demand causes that new materials of higher energy and higher power densities are still under investigation. Herein, we compare electrochemical properties of bismuth vanadate (BiVO4) embedded and not embedded into carbonaceous matrix as an anode material along with structural...
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Advances in mass spectrometry for iron speciation in plants
PublicationIron is an important nutrient essential for plants and critical for human health. The state-of-the art of methods for iron speciation in cereal grains and plant fluids is critically reviewed. Particular attention is given to the latest developments in the coupling of HPLC with the parallel ICP MS and electrospray ionization (ESI) MS/MS detection, usually QTOF MS or Q-Orbitrap MS, for the identification and quantification of iron...
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Thermal degradation kinetics of poly(propylene succinate) prepared with the use of natural origin monomers
PublicationLinear biobased polyester polyols were prepared with the use of succinic acid and 1,3-pro- panediol (both with natural origin). Tetraisopropyl orthotitanate (TPT) was used as a catalyst. In order to determine the effect of various synthesis temperature conditions on the thermal degradation kinet- ics, nine sequences of temperature conditions were used during two-step polycondensation reaction. Thermogravimetric analysis was conducted...
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Widening of the electroactivity potential range by composite formation – capacitive properties of TiO2/BiVO4/PEDOT:PSS electrodes in contact with an aqueous electrolyte
PublicationComposites based on the titania nanotubes were tested in aqueous electrolyte as a potential electrode material for energy storage devices. The nanotubular morphology of TiO2 was obtained by Ti anodization. TiO2 nanotubes were covered by a thin layer of bismuth vanadate using pulsed laser deposition. The formation of the TiO2/BiVO4 junction leads to enhancement of pseudocapacitance in the cathodic potential range. The third component,...
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Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
PublicationWe report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies....
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Properties of Barium Cerate Thin Films Formed Using E-Beam Deposition
PublicationThis article focuses on the properties of the BaCeO3 thin films formed by electron-beam vapor deposition and investigates the formation of barium cerates on supports with different thermal expansion coefficients (Stainless Steel, Invar, Glass Sealing, and Inconel substrates) and the influence of the technological parameters on the properties of the formed thin films with an emphasis on the stability of the films. Morphology and...
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High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles
PublicationAn optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency...
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New insights of nanomaterials usage toward superhydrophobic membranes for water desalination via membrane distillation: A review
PublicationMembrane distillation (MD) is a promising technology for seawater desalination due to the ability to process high-salinity waters and the ability to be driven by low-grade or waste heat. However, practical applications of MD membranes are limited by the low vapor flux and fouling problem. Recently, there is a growing interest in developing novel MD membrane materials with enhanced hydrophobicity to improve the efficiency of desalination...
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Fabrication of toughened plastic using styrene butadiene rubber-poly (methyl methacrylate) interpenetrating polymer networks
PublicationA standard set of interpenetrating polymeric networks (IPNs) has been contrived using an elastomerstyrene butadiene rubber and a thermoplastic poly (methyl methacrylate) through sequential polymerization protocol. This low-cost material can be hopefully engaged as a toughened plastic with cocontinuous morphology. Different morphological protocols including Raman imaging are effectively utilized to envisage the effect of blend ratio...
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Synthesis of Phosphonated Carbon Nanotubes: New Insight into Carbon Nanotubes Functionalization
PublicationCarbon nanotubes were successfully functionalized for the first time in a free radical phosphonylation reaction. Three synthetic protocols were proposed. Carbon nanotubes and diethylphosphite reacted in the presence of known radical initiator, such as azobisisobutyronitrile, single electron oxidant—Mn(OAc)3, or under UV radiation. The functionalized material was fully characterized by means of spectroscopic methods, together with...
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Analysis of the Hydrodynamic Properties of the 3-Column Spar Platform for Offshore Wind Turbines
PublicationThe article presents a design of a floating platform for offshore wind turbines. The concept is a modification of the Spar design and consists of three variable section columns connected to each other by a ballast tank in the lower part of the platform. This solution makes it possible to influence the position of the centre of buoyancy and the centre of mass of the structure. Compared to the classic Spar platform structure, the...
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Glass-ceramic joining of Fe22Cr porous alloy to Crofer22APU: interfacial issues and mechanical properties
PublicationThis work deals with the joining of porous Fe22Cr ferritic stainless steel to a dense Crofer22APU plate by using a silica-based, Ba-containing glass-ceramic. The chemical and interfacial stability and the mechanical properties of the joints were evaluated before and after thermal ageing at 700 ◦C for 500hrs. The sintering behaviour of the glass was assessed by using heating stage microscopy (HSM) to study the influence of a porous...
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Effect of crystallinity on structural, thermal, and in vitro dissolution properties of Na2O-CaO-Nb2O5/MgO-P2O5 glass-ceramics
PublicationThe impact of the crystallinity on structural, thermal, and in vitro dissolution properties were examined for Na2O- CaO-Nb2O5/MgO-P2O5 glasses/glass-ceramics. Glass-ceramics were synthesized via a spontaneous crystallization process. The Nb content in the materials increased with melting temperature, furthermore, the crystallinity is proportional to the Nb content. The presence of crystalline niobates and phosphates is confirmed...
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The saga of a fish: from a survival guide to closing lemmas
PublicationIn the paper by D. Burago, S. Ivanov and A. Novikov, “A survival guide for feeble fish”, it has been shown that a fish with limited velocity can reach any point in the (possibly unbounded) ocean provided that the fluid velocity field is incompressible, bounded and has vanishing mean drift. This result extends some known global controllability theorems though being substantially nonconstructive. We give a fish a different recipe...