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Search results for: KLASYFIKATOR SVM
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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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A Simple Replica Method as the Way to Obtain a Morphologically and Mechanically Bone-like Iron-Based Biodegradable Material
PublicationPorous iron-based scaffolds were prepared by the simple replica method using polyurethane foam as a template and applying the sintering process in a tube furnace. Their surface morphology was characterized using scanning electron microscopy (SEM) and phase homogeneity was confirmed using X-ray diffraction (XRD). Corrosion behavior was determined using immersion and potentiodynamic polarization methods in phosphate buffered saline...
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Resistant to correlated noise and outliers discrete identification of continuous non-linear non-stationary dynamic objects
PublicationIn this article, specific methods of parameter estimation were used to identify the coefficients of continuous models represented by linear and nonlinear differential equations. The necessary discrete-time approximation of the base model is achieved by appropriately tuned FIR linear integral filters. The resulting discrete descriptions, which retain the original continuous parameterization, can then be identified using the classical...
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Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage
PublicationIn this work, we present the preparation and characterization of biomass-derived activatedcarbon (AC) in view of its application as electrode material for electrochemical capacitors. Porouscarbons are prepared by pyrolysis of chestnut seeds and subsequent activation of the obtainedbiochar. We investigate here two activation methods, namely, physical by CO2and chemical usingKOH. Morphology, structure and specific surface area (SSA)...
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Chemia, a ludzki mózg
PublicationWiele substancji chemicznych ma udowodniony wpływ na funkcjonowanie mózgu. Część z nich, jak np. hormony, produkowane są przez sam mózg. Mogą one decydować o wielu naszych zachowaniach oraz, do pewnego stopnia, wpływać na podejmowanie decyzji. Istnieją również substancje wpływające na funkcjonowanie mózgu, które mogą być dostarczane z zewnątrz. Mogą mieć one zarówno pozytywny jak i negatywny wpływ na jego funkcjonowanie. Należy...
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THE APPLICATION OF THE MECHANOCHEMICAL SYNTHESIS FOR THE PREPARATION OF ADVANCED CERAMICS BASED ON BARIUM TITANATE
PublicationIn the present study, the lead-free BaTi1-xZrxO3 (for x = 0, 0.05 and 0.15) ceramics were prepared by High-Energy Ball Milling and heat treatments. The performed X-ray, SEM and EDS measurements confirmed high purity, good quality and the expected quantitative composition of the obtained samples. The study of dielectric properties was performed by means of broadband dielectric spectroscopy at the frequency ranging from 0.1 Hz to...
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On the necessity of experimental verification of numerical results in biomedical applications
PublicationPorous structures made of metal or biopolymers with a structure similar in shape and mechanical properties to human bone can be easily produced by stereolitography techniques, e.g. selective laser melting (SLM). Numerical techniques, like finite element method (FEM) have great potential in testing new, even the most sophisticated designs, according to their mechanical properties, i.e. strength or stiffness. However, due to different...
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Control strategy for the multilevel cascaded H-bridge converter
PublicationThe paper presents the control strategy for Cascaded H-bridge (CHB) converter . The converter output voltage using Space-Vector Pulse Width Modulation (SV-PWM) strategy is controlled. The DC-link voltages are controlled by appropriate choice of H-Bridges and appropriate choice of active and passive vectors.
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Natural radioactivity of solid and liquid phases from shale oil and gas prospection in Pomerania
PublicationIonizing radiation intensity data and estimation of equivalent absorbed dose from solid and liquid samples from prospection of shale gas and oil at selected sites in Pomerania are presented. Naturally occurring radioactive materials (NORM) are associated with geological formations or fluids and can be enhanced during oil and gas production. They appear in e.g. drilling cuttings, flow back water, produced water, scale and sludge....
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Rewitalizacja Warszawskiej Rotundy PKO BP - przeszłość i współczesność
PublicationCharakterystycznym miejscem centrum śródmieścia Warszawy, powszechnie znanym zarówno w kraju jak za granicami naszego kraju był dotychczas, i miejmy nadzieję nadal będzie, okrągły budynek z charakterystycznym pilaście ukształtowanym obrysem wieńczącego go skośnego dachu - obiekt Warszawskiej Rotundy. Rotunda usytuowana przy skrzyżowaniu ulicy Marszałkowskiej i Alei Jerozolimskich - w pobliżu Ronda Dmowskiego w Warszawie jest obiektem,...
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Sprawiedliwość agrarna
Publicationprawiedliwość agrarna została napisana z intencją zreformowania stosunków społeczno-politycznych. Tekst opiera się na założeniu wywodzącym się z tradycji prawnonaturalnej, które brzmi, iż pierwotnie każdy był współwłaścicielem powierzchni Ziemi. Powstanie prywatnej własności ziemskiej (czyli, eo ipso, wywłaszczenie większości ludzi) należy zakwalifikować jako akt bezprawia, kumulujący się w historycznie nawarstwionych nierównościach...
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Shub’s conjecture for smooth longitudinal maps of S^m
PublicationLet f be a smooth map of the m-dimensional sphere Sm to itself, preserving the longitudinal foliation. We estimate from below the number of fixed points of the iterates of f , reduce Shub’s conjecture for longitudinal maps to a lower dimensional classical version, and prove the conjecture in case m = 2 and in a weak form for m = 3.
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Challenges in coupling atmospheric electricity with biological systems
Publication -
Marcin Wekwejt dr inż.
PeopleMarcin Wekwejt, absolwent studiów inżynierskich w inż. biomedycznej (2016; Politechnika Bydgoska im. J. i J. Śniadeckich & Collegium Medicum im. L. Rydygiera), studiów magisterskich w inż. mechaniczno-medycznej (2018; Politechnika Gdańska & Gdański Uniwersytet Medyczny) oraz studiów doktoranckich w dyscyplinie inż. materiałowej (2021, Politechnika Gdańska). Uzyskał z wyróżnieniem stopień naukowy doktora nauk inżynieryjno-technicznych...
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Symptomy spadku konkurencyjności małych i średnich przedsiębiorstw
PublicationAutor w rozdziale tym przedstawił swoje badania, które wykazały, że spadek konkurencyjności przedsiębiorstw jest procesem ciągłym, który każdy właściciel MSP z łatwością może spostrzec nawet z trzyletnim wyprzedzeniem. Nie są potrzebne do tego żadne wyrafinowane narzędzia informatyczne, czy też analityczne. Sam sygnał spadku konkurencyjności, a w efekcie końcowym zagrożenie firmy upadłością można zaobserwować na prostych wskaźnikach...
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Ocena wpływu parametrów nadtapiania laserowego w warunkach kriogenicznych na strukturę warstwy wierzchniej na stopie Ti-6Al-4V
PublicationW pracy zostały przedstawione efekty przetapiania laserowego w warunkach kriogenicznych stopu tytanu Ti-6Al-4V. W celu określenia wpływu obróbki laserowej wykonano analizę mikrostruktury (SEM), składu fazowego (XRD), oraz pomiary mikrotwardości uzyskanych warstw. Stwierdzono, że zmiany podstawowych parametrów przetapiania laserowego - mocy wiązki lasera i prędkości skanowania istotnie wpływają na grubość i mikrostrukturę otrzymanych...
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Effects of manufacturing and face /core bonding on impact damage in glass/polyester - PVC foam core sandwich panels
PublicationZbadano podatność na inicjację uszkodzeń pod wpływem spadającego obciążenia w konstrukcjach przekładkowych poliestrowo szklanych z rdzeniem z pianki PVC przy dwóch sposobach łączenia okładek z rdzeniem: przy pomocy 2 klejów proponowanych do tego celu przez ich producentów oraz czystej żywicy. Zastosowano oprzyrządowany młot spadowy , określając rozmiar zniszczeń na powierzchni próbki metodą wizualna i ultradźwiękową. Inicjacja...
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Production of gaseous matrix-free reference materials. Application of thermoanalytical techniques
PublicationMateriały odniesienia są wykorzystywane w każdym laboratorium w celu zapewnienia jakości wyników pomiarów analitycznych. Produkcja materiałów odniesienia nie jest zadaniem łatwym, szczególnie w przypadku składników gazowych, toksycznych i o nieprzyjemnym zapachu. Termiczny rozkład związków powierzchniowych jest bardzo dogodnym sposobem sporządzania właśnie tego rodzaju mieszanin. Ważną rolę w procesie termicznego rozkładu związków...
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Pomiary temperatury w badaniach diagnostycznych.
PublicationTemperatura to wielkośc fizyczna, która w sposób szczególny odróżnia się od innych cech mierzalnych badanego obiektu. Do określenie jej jednostki niezbędne jest ustalenioe skali temperatur na podstawie stałych punktów termometrycznych . Pomiary< prowadzone w ramach diagnostyki weryfikacyjnej, służą do określenia zdolności danego urządzenia do wykonywania założonych zadań. Przedmiotem badań może być zarówno obiekt cieply, jak i...
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The effect of elevated temperature on LCF damage growth in 2024AA – Experiment and modeling
PublicationThis paper presents the results of experimental low-cycle fatigue (LCF) tests conducted on EN-AW 2024 alloy in T3511 temper at 100 ◦C, 200 ◦C and 300 ◦C. The material’s basic fatigue characteristics were determined, such as fatigue life curve and cyclic strain curve. Both the hysteresis loop and nature of fracture surfaces obtained in macro- and microscopic observations (scanning electron microscope, SEM) were accounted for. The...
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Iterative‐recursive estimation of parameters of regression models with resistance to outliers on practical examples
PublicationHere, identification of processes and systems in the sense of the least sum of absolute values is taken into consideration. The respective absolute value estimators are recognised as exceptionally insensitive to large measurement faults or other defects in the processed data, whereas the classical least squares procedure appears to be completely impractical for processing the data contaminated with such parasitic distortions. Since...
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UNRES-GPU for Physics-Based Coarse-Grained Simulations of Protein Systems at Biological Time- and Size-Scales
PublicationThe dynamics of the virus like particles (VLPs) corresponding to the GII.4 Houston, GII.2 SMV, and GI.1 Norwalk strains of human noroviruses (HuNoV) that cause gastroenteritis was investigated by means of long-time (about 30 μs in the laboratory timescale) molecular dynamics simulations with the coarse-grained UNRES force field. The main motion of VLP units turned out to be the bending at the junction between the P1 subdomain (that...
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Graphene oxide, reduced graphene oxide and composite thin films NO2 sensing properties
PublicationA graphene oxide (GO), reduced graphene oxide (RGO) and poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO composite) gas sensors were successfully fabricated using an electrodeposition method. The electrodeposition was carried out in aqueous GO dispersions. To obtain RGO and PEDOT-RGO, the electrochemical reduction of GO and PEDOT-GO was carried out in 0.1 M KCl at a constant potential of −0.85 V. The GO, RGO and PEDOT-RGO...
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Optimization of Graphene Oxide Synthesis and Its Reduction
PublicationIn this article, we present the review of the chemical methods of synthesis of graphene oxide and its reduction in order to obtain the so-called reduced graphene oxide (rGO) whose properties are similar to those of pure graphene. We also present our experiments and the results in this field and the comparison of the efficiency of different methods of synthesis as well as the reduction of graphene oxide. To characterize the obtained...
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Nanoparticles displacement analysis using optical coherence tomography
PublicationOptical coherence tomography (OCT) is a versatile optical method for cross-sectional and 3D imaging of biological and non-biological objects. Here we are going to present the application of polarization sensitive spectroscopic OCT system (PS-SOCT) for quantitative measurements of materials containing nanoparticles. The PS-SOCT combines the polarization sensitive analysis with time-frequency analysis. In this contribution the benefits...
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On minimum cost edge searching
PublicationWe consider the problem of finding edge search strategies of minimum cost. The cost of a search strategy is the sum of searchers used in the clearing steps of the search. One of the natural questions is whether it is possible to find a search strategy that minimizes both the cost and the number of searchers used to clear a given graph G. We call such a strategy ideal. We prove, by an example, that ideal search strategies do not...
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Partial dominated schedules and minimizing the total completion time of deteriorating jobs
PublicationA problem of scheduling deteriorating jobs on a single processor is considered. The processing time of a job is given by a function pi=ai+bisi, where si is the starting time of the job, ai>=0, bi>=0, for i=1,...,n. Jobs are non-preemptive and independent and there are neither ready times nor deadlines. The goal is to minimize the total weighted completion time. We show how to employ the concept of non-dominated schedules to construct...
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Proces wytwarzania e-kursu. Studium przypadku.
PublicationArtykuł definiuje proces wytwarzania e-kursu i e-lekcji oraz kolejne jego etapy, zaczynając od okre - ślania celu i odbiorcy, a kończąc na udostępnieniu treści. Na podstawie opisanego procesu przedstawiane jest stu - dium przypadku dla e-kursu prowadzonego na studiach zaocznych na Wydziale ETI Politechniki Gdańskiej na przedmiocie Strategie informatyzacji. Artykuł pokazuje też ewaluację studium przypadku, zarówno na poziomie oceny...
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The Influence of Stretch Rod Speed on the Relationship between Preblown Bottle Aesthetic Quality and Final Blown Bottle Thickness Profile in Stretch Blow Molding from Preform Process
PublicationFrom a mechanical point of view, the aesthetic quality of preblown PET bottles and thickness profile of final blown PET bottles manufactured in ISBM process are determined by mechanical and thermal response of blown preforms. From the microscopic point of view the biggest influence on the mechanical and thermal properties of PET bottles have orientation and crystallization processes. From a technological point of view, the aesthetic...
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Short and Long Term Measurements in Assessment of FRP Composite Footbridge Behavior
PublicationThe paper presents application of different sensors for the purpose of short and long term measurements, as well as a structural health monitoring (SHM) system to assess the behavior of a novel fiber reinforced plastics (FRP) composite footbridge. The aim is to present a thorough and concise description of these sensors networks and results gathered with their aid during in situ measurement of strains, displacements, and vibrations,...
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Structural and electrical properties of titanium-doped yttrium niobate
PublicationIn this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type...
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Manganese Phosphatizing Coatings: The Effects of Preparation Conditions on Surface Properties
PublicationManganese phosphate coating could be used to protect the surface of steel products. However, it is essential to determine the effects which process parameters, as well as the types of additives used, have on the efficiency of coating deposition. Thus, we present here a process of phosphatization of low-alloy steel (for 15 min at 95 ◦C) in manganese/nickel baths followed by a passivation process with the use of a silicon and zircon...
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Effects of V2O5 Additive on Structure and Dielectric Properties of BiNbO4 Ceramics
PublicationGoal of the present research was to investigate the influence of V2O5 additive on the structure and dielectric properties of BiNbO4 ceramics. To fabricate BiNbO4 ceramics with V2O5 added the solid state reaction route and pressureless sintering was utilized. Thus obtained ceramics was characterized in terms of its microstructure (SEM), chemical composition (EDS), phase composition and crystalline structure (X-ray phase and structural...
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Metody pomiaru sił hamowania w Stacjach Kontroli pojazdów
PublicationPomiar skuteczności hamowania dotyczy procedury przeprowadzania badań technicznych pojazdów w Stacjach Kontroli Pojazdów. Pomiar ten może być wykonany w jeden z opisanych poniżej trzech sposobów. Problem dotyczy pojazdów zabytkowych, które zwolnione są ustaw regulujących dopuszczalne wartości skuteczności hamowania. Dodatkowy fakt to różnice wynikające z przeprowa-dzania pomiarów trzema sposobami dla pojazdów współczesnych, a pojazdów...
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Badania modelowe dla analizy zasobów i obszaru ochronnego GZWP 208 Biskupiec
PublicationModel matematyczny zbiornika GZWP 208 - Biskupiec wykonano w celu oszacowania jego zasobów oraz weryfikacji granic i obszarów ochronnych. Powierzchnia modelowanego obszaru jest 2,5 razy większa niż sam zbiornik. Dzięki temu uwzględniono główne bazy drenażu, jakimi są głęboko wcięte jeziora: Dadaj, Tejstymy, Gieladzkie i Lampackie, a które znajdują się poza obszarem GZWP 208. Wyniki obliczeń potwierdziły, że zbiornik Biskupiec...
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Sterowanie czujnikami pracującymi w sieci zigbee przy pomocy komend glosowych
PublicationPrzedstawiono bezprzewodową sieć sensorową, pobierającą i przekazującą informacje z czujników temperatury i oświetlenia sterowanych głosem. Funkcjonalność systemu może zostać wykorzystana do sterowania urządzeniami automatyki domowej. System składa się z trzech zasadniczych elementów: koordynatora sieci ZigBee, urządzenia końcowego (pomiarowego) wyposażonego w czujniki światła i temperatury oraz komputera PC. Użytkownik może zarządzać...
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Hydrothermal Cobalt Doping of Titanium Dioxide Nanotubes towards Photoanode Activity Enhancement
PublicationDoping and modification of TiO2 nanotubes were carried out using the hydrothermal method. The introduction of small amounts of cobalt (0.1 at %) into the structure of anatase caused an increase in the absorption of light in the visible spectrum, changes in the position of the flat band potential, a decrease in the threshold potential of water oxidation in the dark, and a significant increase in the anode photocurrent. The material...
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
PublicationThe paper studies the effect of strain-loading sequence on fatigue lifetime and fracture surface topographies in 7075-T651 aluminum alloy specimens. Fatigue tests were performed in two ways: (i) constant-amplitude loading and (ii) two series of variable amplitude loading with non-zero mean strain values. The topography of the fatigue fractures was measured over their entire surfaces with the help of an optical confocal measurement...
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Fast Design Optimization of Waveguide Filters Applying Shape Deformation Techniques
PublicationThis paper presents an efficient design of microwave filters by means of geometry optimization using shape deformation techniques. This design procedure allows for modelling complex 3D geometries which can be fabricated by additive manufacturing (AM). Shape deforming operations are based on radial basis function (RBF) interpolation and are integrated into an electromagnetic field simulator based on the 3D finiteelement method (FEM)....
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Long‐time scale simulations of virus‐like particles from three human‐norovirus strains
PublicationThe dynamics of the virus like particles (VLPs) corresponding to the GII.4 Houston, GII.2 SMV, and GI.1 Norwalk strains of human noroviruses (HuNoV) that cause gastroenteritis was investigated by means of long-time (about 30 μs in the laboratory timescale) molecular dynamics simulations with the coarse-grained UNRES force field. The main motion of VLP units turned out to be the bending at the junction between the P1 subdomain (that...
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Plasmon-enhanced photoluminescence from TiO2 and TeO2 thin films doped by Eu3+ for optoelectronic applications
PublicationIn this work we study the luminescence properties of europium-doped titanium dioxide and tellurium oxide thin films enhanced by gold plasmonic nanostructures. We propose a new type of plasmon structure with an ultrathin dielectric film between plasmonic platform and luminescent material. Plasmonic platforms were manufactured through thermal annealing of the gold thin film. Thermal dewetting of gold film results in spherical gold...
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Assessment of the devulcanization process of EPDM waste from roofing systems by combined thermomechanical/microwave procedures
PublicationEthylene-propylene-diene rubber (EPDM) is a elastomer widely used in common industrial applications. EPDM can be shaped into sheets and employed as isolating material for roofing systems. In this study, scraps of EPDM from commercial, industrial and residential roofing systems were treated by combined thermo-mechanical and microwave devulcanization processes including peroxide of benzoyl (BPO). The devulcanized EPDM (Dev-EPDM)...
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3D point cloud as a representation of buildings: the Nanotechnology Center and the Auditorium Novum
Open Research DataThe product presents the point cloud in the collection of a three-dimensional database in spatial order as the representations of the Nanotechnology Center and the Auditorium Novum buildings (located on the campus of the Gdańsk University of Technology) acquired in the laser scanning technology. According to its high accuracy and precision of data acquisition...
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Surface-dependent biological potential of spherical silver nanoparticles
Open Research DataThe growing interest in silver nanoparticles (AgNPs) is largely driven by their significant antimicrobial potential. As carriers of reactive silver ions on a nanoscale, AgNPs are considered excellent candidates for specific antibacterial strategies. Numerous scientific studies have highlighted that AgNPs are broad-spectrum antimicrobials, with their...
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Cross-linking of sodium caseinate-structured emulsion with transglutaminase alters postprandial metabolic and appetite responses in healthy young individuals
PublicationThe physico-chemical and interfacial properties of fat emulsions influence lipid digestion and may affect postprandial responses. The aim of the present study was to determine the effects of the modification of the interfacial layer of a fat emulsion by cross-linking on postprandial metabolic and appetite responses. A total of fifteen healthy individuals (26·5 (sem 6·9) years and BMI 21·9 (sem 2·0) kg/m2) participated in a cross-over...
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High frequency oscillations are associated with cognitive processing in human recognition memory
PublicationHigh frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30-100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans demonstrate that physiological oscillations...
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Underground Water Level Prediction in Remote Sensing Images Using Improved Hydro Index Value with Ensemble Classifier
PublicationThe economic sustainability of aquifers across the world relies on accurate and rapid estimates of groundwater storage changes, but this becomes difficult due to the absence of insitu groundwater surveys in most areas. By closing the water balance, hydrologic remote sensing measures offer a possible method for quantifying changes in groundwater storage. However, it is uncertain to what extent remote sensing data can provide an...
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Acoustic streaming caused by some types of aperiodic sound. Buildup of acoustic streaming
PublicationThe analysis of streaming caused by aperiodic sound of different types (switched on at transducer sound or sound determined by initial conditions) is undertaken. The analysis bases on analytical governing equation for streaming Eulerian velocity, which is a result of decomposition of the hydrodynamic equations into acoustic and non-acoustic parts. Its driving force (of acoustic nature) represents a sum of two terms; one is the...
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Self-organizing maps classification of epidemiological data and toenail selenium content monitored on cancer and healthy patients from Poland
PublicationW pracy przedstawiono wyniki wielowymiarowej analizy danych pomiarowych (przy wykorzystaniu techniki samoorganizującej sie mapy (SOM))nad oszacowaniem zawartości selenu w próbkach paznokci pobranych od mieszkańców Województwa Pomorskiego ((w tym od grupy osób zdrowych i ze zdiagnozowaną chorobą nowotworową) i Lubuskiego. W wyniku przeprowadzonej analizy uzyskano podział uczestników ze zdiagnozowanym nowotworem na trzy różne grupy:1...
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Wpływ przeestryfikowania chemicznego na właściwości trójskładnikowych mieszanek tłuszczowych
PublicationUżywając trzech surowców tłuszczowych: oleju rzepakowego, oleju kokosowego i podwójnie frakcjonowanej stearyny palmowej oraz stosując kombinację dwóch metod modyfikacji: mieszania i przeestryfikowania chemicznego otrzymano pięć różnych tłuszczów. Przeestryfikowano mieszankę trójskładnikową, oraz trzy mieszanki dwuskładnikowe. Te ostatnie następnie zostały zmieszane z trzecim tłuszczem. We wszystkich otrzymanych tłuszczach stosunek...