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Search results for: ROC CURVE
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Local chirality measures in QSPR : IR and VCD spectroscopy
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Evaluation of adhesion strength, corrosion, and biological properties of the MWCNT/TiO2 coating intended for medical applications
PublicationMulti-wall carbon nanotube (MWCNT) coatings are gaining increasing interest because of their special properties used in many science fields. The titania coatings are known for their improvement of osteoblast adhesion, thus changing the surface architecture. Bi-layer coatings comprising 0.25 wt% of the MWCNTs and 0.30 wt% of titania (anatase structure) were synthesized in a two-stage procedure using the electrophoretic deposition...
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ZnO-decorated green-synthesized multi-doped carbon dots from Chlorella pyrenoidosa for sustainable photocatalytic carbamazepine degradation
PublicationThe promising green synthesis of carbon dots (CDs) from microalga Chlorella pyrenoidosa was achieved using simple hydrothermal and microwave-assisted methods. Doping of nanomaterials by nonmetals (N, S, and P) was confirmed by X-ray photoelectron spectroscopy (XPS), while the existence of metals in the CDs was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM),...
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Novel tetrahedral cobalt(II) silanethiolates: structures and magnetism
PublicationThree heteroleptic complexes of Co(II) tri-tert-butoxysilanethiolates have been synthesized with piperidine [Co{SSi(OtBu)3}2(ppd)2] 1, piperazine [Co{SSi(OtBu)3}2(NH3)]2(μ-ppz)·2CH3CN 2, and N-ethylimidazole [Co{SSi(OtBu)3}2(etim)2] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(II) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear,...
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Free-standing TiO2 nanotubes decorated with spherical nickel nanoparticles as a cost-efficient electrocatalyst for oxygen evolution reaction
PublicationHere, we report significant activity towards the oxygen evolution reaction (OER) of spherical nickel nanoparticles (NPs) electrodeposited onto free-standing TiO2 nanotubes (TNT) via cyclic voltammetry. It has been shown that simple manipulation of processing parameters, including scan rate and number of cycles, allows for formation of the NPs in various diameters and amounts. The polarization data with respect to transmission electron...
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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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Study on the flammability, thermal stability and diffusivity of polyethylene nanocomposites containing few layered tungsten disulfide (WS2) functionalized with metal oxides
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A facile synthesis method and electrochemical studies of a hierarchical structured MoS2/C-nanocomposite
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Correction: MOF-5 derived carbon as material for CO2 adsorption
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MOF-5 derived carbon as material for CO2 absorption
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Enhancement of photocatalytic hydrogen evolution with catalysts based on carbonized MOF-5 and g-C3N4
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Reactions of cobalt(ii) chloride and cobalt(ii) acetate with hemisalen-type ligands: ligand transformation, oxidation of cobalt and complex formation. Preliminary study on the cytotoxicity of Co(ii) and Co(iii) hemisalen complexes
PublicationSeveral molecular cobalt(II) complexes, one Co(II) coordination polymer, and one ionic cobalt(III) complex with imine hemisalen ligands were synthesized. The hemisalen ligands were synthesized from o-vanillin (oVP) and diverse aminopyridines (compounds HL1–HL4) or aminophenol (compound HL5). It was observed that cobalt(II) chloride in dry acetonitrile catalyzes a transformation of HL1 and HL3 instead of complex formation. The conversion...
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Convenient and efficient synthesis of functionalized unsymmetrical Z-alkenyl disulfanes
PublicationWe developed a simple and efficient method for the synthesis of functionalized unsymmetrical Z-alkenyl disulfanes under mild conditions in moderate to good yields. The designed method is based on the reaction of Z-alkenyl thiotosylates with thiols in the presence of base. The developed method allows the preparation of unsymmetrical Z-alkenyl disulfanes bearing additional hydroxy, carboxy, or amino functionalities.
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Up-conversion white emission and other luminescence properties of a YAG:Yb2O3·Tm2O3·Ho2O3@SiO2 glass-nanocomposite
PublicationWe report on a glass-nanocomposite material consisting of yttrium aluminum garnet (Y3Al5O12, YAG) nanocrystals co-doped with Yb3+, Tm3+ and Ho3+ ions as well as entrapped into a SiO2 xerogel. This 94YAG·5Yb2O3·0.8Tm2O3·0.2Ho2O3@SiO2 (abbr. YAG:YbTmHo@SiO2) nanocomposite material has been prepared by sol–gel procedure. Its structure and morphology has been characterized by means of X-ray diffraction (XRD) and scanning electron microscope...
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Effect of cobalt addition on the corrosion behaviorof near equiatomic NiTi shape memory alloy in normal saline solution: electrochemical and XPS studies
PublicationThe electrochemical and corrosion (uniform and localized) behavior of a binary Ni52Ti48 shape memory alloy (SMA) and two ternary Ni52Ti48-xCox (x = 1.5 and 4.0 wt.%) SMAs were studied. Measurements were conducted in 0.9% NaCl solution at 37 oC employing various electrochemical methods. These include: linear polarization resistance (LPR), linear sweep voltammetry (LSV), chronoamperometry and dynamic electrochemical impedance spectroscopy...
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Degradation kinetics and mechanism of pentoxifylline by ultraviolet activated peroxydisulfate
PublicationDegradation of pentoxifylline (PTX) by sodium peroxydisulfate (SPDS) assisted by UV irradiation has been investigated in deionized water. The treatment was more favorable over direct photolysis or peroxydisulfate oxidation alone. The effects of various parameters, including different dosage of oxidant agent, PTX concentration, initial solution pH levels, and the presence of inorganic ions like chloride, nitrate and carbonate have...
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5-Selenocyanato and 5-trifluoromethanesulfonyl derivatives of 2′-deoxyuridine: synthesis, radiation and computational chemistry as well as cytotoxicity
Publication5-Selenocyanato-2′-deoxyuridine (SeCNdU) and 5-trifluoromethanesulfonyl-2′-deoxyuridine (OTfdU) have been synthesized and their structures have been confirmed with NMR and MS methods. Both compounds undergo dissociative electron attachment (DEA) when irradiated with X-rays in an aqueous solution containing a hydroxyl radical scavenger. The DEA yield of SeCNdU significantly exceeds that of 5-bromo-2′-deoxyuridine (BrdU), remaining...
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Diaminophosphinoboranes: effective reagents for phosphinoboration of CO2
PublicationThe monomeric diaminophosphinoboranes readily react with CO2 under mild conditions to cleanly form products of the general formula R2P-C(=O)-O-B(NR2)2 in the absence of a catalyst. The isolated products from the CO2-phosphinoboration were fully characterized by NMR spectroscopy, IR spectroscopy, and X-ray diffraction. The mechanism of CO2 phosphinoboration with diaminophosphinoboranes was elucidated by DFT calculations.
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Anticancer and antimicrobial properties of novel η6-p-cymene ruthenium(ii) complexes containing a N,S-type ligand, their structural and theoretical characterization
PublicationRuthenium(II) complexes are lately of great scientific interest due to their chemotherapeutic potential asanticancer and antimicrobial agents. Here we present the synthesis of new pyrazole carbothioamidederivatives and their four arene–ruthenium complexes. The title compounds were characterized with theapplication of IR, NMR, mass spectrometry, elemental analysis and X-ray diffraction. Additionally, for newcomplexes DFT calculations...
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Activation of the C=P bond in phosphanylphosphaalkenes C=P–P bond system) in the reaction with nucleophilic reagents: MeLi, nBuLi and tBuLi
PublicationThree reactions of phosphanylphosphaalkene (1) with nucleophiles were performed to activate the diphosphorus monomer. We observed similar results in the reactions with MeLi and nBuLi, in which the P–P bond is cleavaged and triphosphorus systems [P(Me)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1a'') and [P(nBu)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1b''), respectively, are formed depending on the nucleophilic reagent (biph ¼ biphenyl). In the...
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Structure and transport properties of triple-conducting BaxSr1−xTi1−yFeyO3−δ oxides
PublicationIn this work, BaxSr1−xTi1−yFeyO3−δ perovskite-based mixed conducting ceramics (for x = 0, 0.2, 0.5 and y = 0.1, 0.8) were synthesized and studied. The structural analysis based on the X-ray diffraction results showed significant changes in the unit cell volume and Fe(Ti)–O distance as a function of Ba content. The morphology of the synthesized samples studied by means of scanning electron microscopy has shown different microstructures...
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Solvothermal synthesis and structural characterization of three polyoxotitanium-organic acid clusters
PublicationThree new titanium oxo-clusters Ti4O2(OiPr)10(OOCPhMe)2 (I), Ti6O4(OEt)8(OOCPhMe)8 (II) and Ti6O6(OEt)6(OOCCHPh2)6 (III) were obtained by easy one-step solvothermal reactions of titanium(IV) isopropoxide, alcohols and carboxylic acids. The three compounds were characterized by single-crystal and powder X-ray diffraction, TGA/DSC, optical and electron microscopy, and FTIR and NMR spectroscopy. X-ray powder diffraction and spectroscopy...
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Ho2Pd1.3Ge2.7 – a ternary AlB2-type cluster glass system
PublicationWe report a successful synthesis of a ternary AlB2-type intermetallic compound. The phase purity was obtained by fine-tuning the Pd-Ge ratio out of the idealized 1-3. Attempts to synthesize an Er analogue were not successful. We discuss the instability of the Er analogue based on the atomic size ratio and also suggest that the increased stability of Ho2Pd1+xGe3−x in the Pd-rich range likely stems from a combination of atomic size...
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Pseudo-superparamagnetic behaviour of bariumhexaferrite particles
PublicationThe effect of hexadecyltrimethylammonium bromide (CTAB) addition on the crystal structure, morphology,and magnetic properties of co-precipitated hexagonal barium ferrite was investigated. For afixed amount ofsurfactant, different Fe3+concentrations and Fe3+/Ba2+ratios were used to optimize the formation ofsingle-phase barium ferrite particles. The results indicated that the obtained ferrite particles exhibitedcoercivity changes...
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Highly stable organic–inorganic junction composed of hydrogenated titania nanotubes infiltrated by a conducting polymer
PublicationA poly(3,4-ethylenedioxythiophene) conducting polymer doped with poly(2-styrene sulfonate) (pEDOT:PSS) was efficiently electrodeposited on a layer composed of ordered titania nanotubes. TiO2 nanotubes were formed during an anodization process and, after calcinations, a layer was subjected to hydrogen plasma. Hydrogenation leads to Ti(III) formation, a decrease in resistance, and a huge increase of donor density when compared with...
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Convenient and efficient synthesis of functionalized unsymmetrical alkynyl sulfides
PublicationWe developed a simple and efficient method for the synthesis of functionalized unsymmetrical alkynyl sulfides under mild conditions in good yields. The designed method is based on the reaction of 5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-disulfanyl derivatives with lithium acetylides. The developed method allows the preparation of unsymmetrical alkynyl sulfides bearing additional hydroxyl, carboxyl, or amino functionalities.
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Synthetic lipopeptides as potential topical therapeutics in wound and skin care: in vitro studies of permeation and skin cells behaviour
PublicationSeveral Gly-His-Lys analogues were obtained to investigate their antimicrobial properties. Three lipophilic analogues with the structure numbering 1b, 2b, 4b, exhibit significant effect against bacteria and were selected for in vitro evaluation of skin cells behaviour. In the present studies, an in vitro model of wound repair, proliferative cell staining, and tracking of living cells were used. Cell proliferation and cell migration,...
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Catalytic impact of alloyed Al on the corrosion behavior of Co50Ni23Ga26Al1.0 magnetic shape memory alloy and catalysis applications for efficient electrochemical H2 generation
PublicationThe electrochemical and corrosion behaviour of Co50Ni23Ga27-xAlx (x = 0 and 1.0 wt%) magnetic shape memory alloys (MSMAs) was studied in 0.5 M NaCl solutions using various electrochemical techniques. Results showed remarkable activation of the tested MSMA toward pitting corrosion upon alloying it with Al. XPS examination confirmed the activation influence of alloyed Al. It proved that the presence of Al in the alloy's matrix weakens...
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Tradycje kształcenia praktycznego na Wydziale Mechanicznym Politechniki Gdańskiej
PublicationPrzedstawiono skrótowo historię kształcenia technicznego na Wydziale Mechanicznym Politechniki Gdańskiej od roku 1945. Omówiono wyższe szkolnictwo techniczne w Gdańsku od 1904 roku, ze szczególnym uwzględnieniem zajęć praktycznych. Rok akademicki 2004/2005 był na Politechnice Gdańskiej Rokiem Jubileuszowym, w związku ze 100. leciem Politechniki w Gdańsku i 60. rocznicą Politechniki Gdańskiej, w tym również Wydziału Mechanicznego.
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Podsumowanie uzyskanych informacji literaturowych o procesie orientowania i krystalizowania tworzywa PET w procesie SBM z preformy
PublicationW artykule zostaną omówione procesy orientowania i krystalizowania tworzywa PET (politeraftalanu etylenu) w procesie SBM (ang. stretch blow molding process) produkcji butelek PET przeznaczonych do magazynowania napojów spożywczych gazowanych (butelki CSD - carbonated soft drink). Artykuł opracowano na podstawie zebranych danych literaturowych. Bardziej szczegółowe opracowanie zostanie przedstawione w monografii planowanej do druku...
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Total restrained bondage in graphs
PublicationPodzbiór D zbioru wierzchołków grafu nazywamy zewnętrznie totalnym dominującym w grafie, jeśli każdy wierzchołek spoza D ma sąsiada zarówno w D jak i poza D. Moc najmniejszego zbioru o tej własności nazywamy liczbą dominowania zewnętrznie totalnego. W artykule badamy wpływ usuwania krawędzi na liczbę dominowania zewnętrznie totalnego, czyli liczbę zewnętrznego totalnego zniewolenie w grafach.
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Analiza charakterystyk parku wiatrowego.
PublicationPrognozowanie mocy parków wiatrowych nie należy do łatwych przedsięwzięć, nie tylko ze względu na stochastyczny charakter wymuszenia (wiatru), ale wiele innych czynników mających wpływ na wartość prognozy. W artykule przedstawiono główne czynniki wpływające na moc parku wiatrowego: prędkość wiatru, kierunek wiatru, pionowy profil wiatru, przesłonięcie oraz dynamika zmian wiatru. Rozważania poparto na wynikach pomiarów.
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Wykorzystanie biomasy w źródłach ciepła średniej i małej mocy na przykładzie Województwa Pomorskiego
PublicationZbilansowano zasoby biomasy województwa pomorskiego, możliwej do pozyskania z drewna, słomy i plantacji energetycznych. Podano przykłady dotychczasowego wykorzystania biomasy oraz prognozy dalszego jej wykorzystania w województwie pomorskim. Określono też aktualne zapotrzebowanie na moc cieplną wybranych gmin województwa (Czersk, Chojnice, Łęczyce, Nowa Wieś Lęborska, Puck, Skarszewy). Wytypowano też gminy o najwyższym potencjale...
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Requirements for Residual Current Devices Intended for Electric Vehicle Charging Systems
PublicationThe properties of residual current devices have been presented from the point of view of their ability to detect a specific shape of the residual current waveform. Moreover, the standard requirements relating to residual current protection used in electric vehicle charging installations have been pointed out. The operating characteristics of the IC-CPD and RDC-DD protections, which are intended for charging electric vehicles in...
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METODA POŚREDNIEGO WYZNACZANIA MOCY EFEKTYWNEJ WOLNOOBROTOWEGO SILNIKA OKRĘTOWEGO NA PODSTAWIE EKSPLOATACYJNYCH POMIARÓW CIŚNIENIA POWIETRZA DOŁADOWUJĄCEGO
PublicationW artykule przedstawionometodę, która pozwala w przybliżony sposób wyznaczyć względną moc okrętowego silnika głównego w warunkach eksploatacji na podstawie standardowego pomiaru ciśnienia powietrza doładowującego wkanaledolotowym. Metoda oparta jest na określaniuwspółczynnikówaproksymującej funkcji liniowej, przy znanym ciśnieniu doładowania oraz rodzaju i mocy nominalnejsilnika.Jest ona uzupełnieniem innych metodpośredniego...
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Obciążanie jednostek elektrowni szczytowo-pompowych w zależności od krzywej dobowego wytwarzania mocy w KSE
PublicationNa podstawie badań wysokości obciążeń jednostek w elektrowniach szczytowo-pompowych oraz dobowej zmienności zapotrzebowania na moc w krajowym systemie elektroenergetycznym (KSE), przedstawiono związki zachodzące pomiędzy obciążaniem liczby hydrozespołów w elektrowniach pompowych Żarnowiec i Porąbka - Żar a kształtem krzywej dobowego wytwarzania mocy w KSE dla dni roboczych, sobót, niedziel i dni świątecznych dla różnych pór roku.
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The Impact of Concentration on Secors' Output Level in the European Union (1997-2005)
PublicationThis paper examines the impact of concentration on growthof selected 43 sectors within ten European countries over the period of time 1997-2005. We apply system GMM estimator to the extendedversion of production function, including as explanatory variablesindustry specific measures of concentration. We found the relationbetween output and concentration measured by the Herfindahl-Hirschman Index (HHI) to be non-monotonic having...
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SUBSOIL CHARACTERISTICS OF THE VISTULA RIVER DIKES
PublicationThe results of CPTU tests are used to determine the strength parameters of a dike subsoil. Stress state and stress history of the subsoil under the flood embankment was evaluated with CPTU and DMT tests. Normally consolidated soil was found under the central part of the dike, while the subsoil near the dike toe is found to be overconsolidated. Due to consolidation the undrained shear strength of the subsoil under the central part...
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Frequency response spectra applied to assess efficiency of the training techniques
PublicationThe purpose of the research is to assess the increase of the muscle strength and power. Movement of the human body when the moving one impacts a stationary or moving body is taken under consideration. The waveform produced by an impact is transformed into frequency domain. The acceleration record is transformed as a complex spectrum, by the use of a Discrete Fourier Transformation. In this paper the applications of the discrete...
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Centrally Pivoted Tilting Pad Thrust Bearing with Carbon-Based Coated Collar—Experimental Results of Low- and Medium-Speed Operation
PublicationExperimental results of the research on a tilting pad thrust bearing with symmetrical pad support in the conditions of high loads and low speeds are presented in the paper. As described in the literature review, experimental results of tilting pad bearings at low speed/high load regime and transient conditions are rare. Unusual material selection - steel pad against a DLC-type coating on the collar was utilized. Such material combination...
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Edge-Computing based Secure E-learning Platforms
PublicationImplementation of Information and Communication Technologies (ICT) in E-Learning environments have brought up dramatic changes in the current educational sector. Distance learning, online learning, and networked learning are few examples that promote educational interaction between students, lecturers and learning communities. Although being an efficient form of real learning resource, online electronic resources are subject to...
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Surface Texture Analysis of Hardened Shafts after Ceramic Ball Burnishing
PublicationThis article represents the results of testing the surface condition of shafts manufactured by the burnishing process. The shafts with a hardness of approximately 62 HRC (Rockwell C). were burnished with a ceramic ball (Si3N4), where the force range was controlled by the means of a hydraulic system. The machining process consisted of hard turning shafts with cubic boron nitride (CBN) inserts, followed by burnishing with the use...
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Recent Achievements in Constitutive Equations of Laminates and Functionally Graded Structures Formulated in the Resultant Nonlinear Shell Theory
PublicationThe development of constitutive equations formulated in the resultant nonlinear shell theory is presented. The specific features of the present shell theory are drilling rotation naturally included in the formulation and asymmetric measures of strains and stress resultants. The special attention in the chapter is given to recent achievements: progressive failure analysis of laminated shells and elastoplastic constitutive relation...
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Two- and three-dimensional elastic networks with rigid junctions: modeling within the theory of micropolar shells and solids
PublicationFor two- and three-dimensional elastic structures made of families of flexible elastic fibers undergoing finite deformations, we propose homogenized models within the micropolar elasticity. Here we restrict ourselves to networks with rigid connections between fibers. In other words, we assume that the fibers keep their orthogonality during deformation. Starting from a fiber as the basic structured element modeled by the Cosserat...
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Multi-functional sensor based on photonic crystal fiber using plasmonic material and magnetic fluid
PublicationA unique highly sensitive photonic crystal fiber is investigated based on plasmonic material and magnetic fluid (MF) for the simultaneous measurement of temperature and magnetic field sensor. The designed sensor is explored by tracing the different parameters such as birefringence, coupling length, power spectrum, and the peak wavelength of the transmission intensity. The magnetic field and temperature computation are attained...
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Shear band evolution phenomena in direct shear test modelled with DEM.
PublicationA direct shear test is widely used in the geotechnical engineering field. It is an easy and quick test to measure the shear properties of soil. This test often replaces more expensive and difficult tri-axial shear test. Despite that the direct shear test is known and used for a long time, it is still not well investigated at the grain scale. This paper deals with the micro behaviour of the cohesionless sand inside the direct shear...
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Curing epoxy with ethylenediaminetetraacetic acid (EDTA) surface-functionalized Co Fe3-O4 magnetic nanoparticles
PublicationIn this work, the bulk and surface composition of Fe3O4 supermagnetic nanoparticles were modified for efficient epoxy curing. The bare, ethylenediaminetetraacetic acid (EDTA) capped, and cobalt (Co)-doped EDTA capped Fe3O4 nanoparticles were synthesized electrochemically. The crystalline structure and phase information, surface capping, morphology and magnetization behavior of nanoparticles were studied by X-Ray diffraction (XRD),...
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Open source solution LMS for supporting e-learning/blended learning engineers
PublicationW artykule zaprezentowano darmowe systemy zarządzania kształceniem na odległość wspomagające e-learningowe/mieszane nauczanie inżynierów. Pierwszy system TeleCAD został opracowany w ramach projektu Leonardo da Vinci (1998-2001). System TeleCAD był propozycją w projekcie V Ramowy CURE (2003-2006). W roku 2003 dzięki projektowi Leonardo da Vinci EMDEL (2001-2005) Centrum Edukacji Niestacjonarnej Politechniki Gdańskiej wybrało system...
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NEW TRENDS IN DEVELOPMENT OF ORC'S FOR MICROPOWER GENERATION
PublicationIn the paper, new trends in development of micropower generation of heat and electricity are presented. New type of CHP for domestic usage is developed in the Institute of Fluid-Flow Machinery PAS and methods of its design are presented. The most promising trends in equipment of ORC cycle for this purpose were discussed. Main attention was focused on micro-heat exchangers design based on micro-channels and micro-jets. In our opinion...
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Analiza funkcjonowania polskiego rynku energii elektrycznej w okresie wprowadzenia stopni zasilania w 2015 roku
PublicationPrzedstawiono opis sytuacji, która doprowadziła do wprowadzenia wysokich stopni zasilania w KSE w sierpniu 2015 r. Omówiono przyczyny i konsekwencje wprowadzenia stopni zasilania, na podstawie analizy zapotrzebowania na moc w KSE. Przedstawiono analizę cen i obrotów na Rynku Bilansującym w tym okresie. Opisano wpływ nietypowej sytuacji na Giełdę Energii oraz na ceny na rynku „spotowym” i rynkach terminowych.