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Search results for: FERROMAGNETIC GRANULES
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Transport Properties of Nitrided VN-SiO2 Sol-Gel derived films
PublicationPraca dotyczy transportu elektrycznego stałoprądowego cienkich warstw xVN-(100-x)SiO2 (gdzie x = 90, 80, 70, 60 mol%)otrzymanych w wyniku termicznego azotowania warstw tlenkowych otrzymanych metodą zol-żel. W warstwach obserwuje się granule VN rozdyspergowane w amorficznej matrycy SiO2. Warstwy wykazują przejście nadprzewodzące w temperaturze około 7,5K. W stanie normalnym ich przewodnictwo można opisać modelem charaktrystycznym...
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Application of the Barkhausen effect probe with adjustable m agnetic field direction for stress state determination in the P91 ste el pipe
PublicationThe paper presents the results of application of a novel Barkhausen effect (BE) probe with adjustable magnetizing field direction for the stress level evaluation in ferromagnetic materials. The investigated sample was in a form of a pipe, made of P91 steel that was anisotropic due to the production process. The measurements were performed before and after welding, revealing the influence of welding process on the residual stress...
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Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
PublicationInfluence of two factors: the variable cross-section and the localized plastic deformation, which affect the stray magnetic field profile of a ferromagnetic sample have been studied. Evaluation of an effect size is based on the analysis of the stray magnetic field component which is tangential to the longest dimension of a sample. However, in order to describe the nature of the stray magnetic field, the normal component (perpendicular...
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Lattice-commensurate skyrmion texture in a centrosymmetric breathing kagome magnet
PublicationSkyrmion lattices (SkL) in centrosymmetric materials typically have a magnetic period on the nanometer-scale, so that the coupling between magnetic superstructures and the underlying crystal lattice cannot be neglected. We reveal the commensurate locking of a SkL to the atomic lattice in Gd3Ru4Al12 via high-resolution resonant elastic x-ray scattering (REXS). Weak easy-plane magnetic anisotropy, demonstrated here by a combination...
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LuAlO/sub 3/:Ce and other aluminate scintillators
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Method of managing drill cuttings from shale gas formations
PublicationProposed management method of drill cuttings involves recycling for the expanded clay production. A theoretical presentation of the possibility, choosing planning path based on similarity between the materials used in the manufacture of expanded clay and oily cuttings. Application for the main stages of manufacture of expanded clay production of drill cuttings from shale gas extraction. Introduced into circulation solid waste partly...
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Molecular mobility of water protons under interaction with chemically modified starches. DSC and HMR-relaxation investigations
PublicationThe change of water protons mobility in the system chemically modified starches – water were investigated by DSC and NMR-relaxation methods. The amount of unfrozen water at subzero temperature as well as additional unfrozen water which appears after gelatinization have lower values for chemically modified starches in comparison with the native starch. The proton spin-spin relaxation time Т2 for chemically modified starch samples,...
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Meso‐scale analyses of size effect in brittle materials using DEM
PublicationThe paper describes numerical meso-scale results of a size effect on strength, brittleness and fracture in brittle materials like concrete. The discrete element method (DEM) was used to simulate the size effect during quasi-static splitting tension with the experimental-based meso-structure. The two-dimensional (2D) calculations were carried out on concrete cylindrical specimens with two diameters wherein two different failure...
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Modelling of fracture process in concrete using a novel lattice model.
PublicationArtykuł omawia wyniki modelowania procesu zarysowania w elementach betonowych przy zastosowaniu dyskretnego modelu kratownicowego. Beton był modelowany na poziomie mezoskali z uwzględnieniem 3 faz: kruszywa, zaczynu cementowego i stref kontaktu. Obliczenia wykonano dla rozciągania i ścinania połączonego z rozciąganiem.
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FE-calculations of stress distribution under prismatic and conical sandpiles within hypoplasticity
PublicationW artykule przedstawiono wyniki numerycznej rozkładu naprężeń pod pryzmatycznymi i stożkowymi stosami piasku w ramach mikropolarnej hipoplastyczności. Wyniki pokazują, że rozkład naprężeń zależy od sposobu napełnienia stożku piaskiem. W niektórych przypadkach, maksymalne naprężenie nie występuje w środku stosu piasku.
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FE-investigations of micro-polar boundary conditions along interface between soil and structure
PublicationW artykule zaproponowano mikropolarne warunki brzegowe w strefie kontaktu materiału granulowanego ze ścianą konstrukcji. Warunki te umożliwiają wyznaczenie grubości strefy kontaktu w zależności od szorstkości ściany. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i mikropolarnego modelu hipoplastycznego.
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Modelling of concrete behaviour in uniaxial compression and tension with DEM.
PublicationW artykule omowiono wyniki modelowania betonu podczas jednoosiowego sciskania i rozciagania stosujac metode elementów dyskretnych. Beton zostal opisany jako material 3-fazowy (kruszywo, zaprawa cementowa i strefy kontaktu). Szczegolna uwage zwrocono na zjawiska mikro-strukturalne na poziomie kruszywa (lancuchy sil, wiry, obroty ziaren). Wyniki numeryczne zostaly porownano z wynikami badan doswiadczalnych.
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Investigations of quasi-static vortex structures in 2D sand specimen under passive earth pressure conditions based on DEM and Helmholtz-Hodge vector field decomposition.
PublicationArtykuł przedstawia wyniki obliczeń quasi-statycznych struktur wirowych w 2-wymiarowej próbce piasku w warunkach pasywnego parcia gruntu. Zastosowano metodę elementów dyskretnych i dekompozycję Helmholtza-Hodge’a pola wektorowego. Stwierdzono bliską zależność między wirami a miejscem powstania strefy lokalizacji odkształceń stycznych.
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Effect of free water on the quasi‑static compression behavior of partially‑saturated concrete with a fully coupled DEM/CFD approach.
PublicationThe work aims to numerically investigate the quasi-static response of partially fluid-saturated concrete under two-dimensional uniaxial compression at the mesoscale. We investigated how the impact of free pore fluid content (water and gas) affected the quasi-static strength of concrete. The totally and partially fluid-saturated concrete behavior was simulated using an improved pore-scale hydro-mechanical model based on DEM/CFD....
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Effect of grain roughness on strength, volume changes, elastic and dissipated energies during quasi-static homogeneous triaxial compression using DEM
PublicationArtykuł omawia wpływ szorstkości ziaren na wytrzymałość, zmiany objętościowe, sprężyste i dysypywane energie podczas jednorodnego quasi-statycznego trójosiowego ściskania. Obliczenia wykonano stosując metodę elementów dyskretnych. W obliczeniach zastosowano różne szorstkości ziaren.
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Influence of permanent magnetic field on wear performance of dry sliding contacts
PublicationResults of experimental studies concerning the influence of permanent magnetic field on wear of dry sliding contact are presented.It was found that magnetic field of horizontal orientation is causing temporary reduction of material's hardness. It also facilitates and accelerates removal process of wear particles from the contact zone.Formation of bulges, consisting of accumulated and compacted anti-ferromagnetic material produced...
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Determination of magnetisation conditions in a Double-Core Barkhausen Noise measurement set-up
PublicationThe magnetic Barkhausen effect is useful forassessing 1D and 2D stress states of ferromagnetic steelobjects. However, its extension to technically importantmaterials, such as duplex anisotropic steels, remains challenging. The determination of magnetisation inside the studied object and the electromagnet for various geometries, materials and magnetisation angles is a key issue.Three-dimensional, dynamic finite element analysis...
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A first-principles study of electronic and magnetic properties of 4d transition metals doped in Wurtzite GaN for spintronics applications
PublicationWe studied the electronic and magnetic properties of wurtzite GaN (w-GaN) doped with different concentrations of the 4d transition metal ions Nb, Mo, and Ru. We incorporated spin-polarized plane-wave density functional theory within an ultrasoft pseudopotential formalism. The 4d transition metals were doped at different geometrical sites to determine the geometry with the lowest total energy and the one that induced the largest...
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Electric and magnetic properties of Lanthanum Barium Cobaltite
PublicationThe cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3)...
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Charge density wave, enhanced mobility, and large nonsaturating magnetoresistance across the magnetic states of HoNiC2 and ErNiC2
PublicationWe report on magnetotransport and thermoelectric properties of two ternary carbides HoNiC2 and ErNiC2 hosting both charge density wave and long-range magnetic order. In the charge density wave state, both compounds show relatively large magnetoresistance MR ≈ 150% in HoNiC2 and ≈ 70%in ErNiC2 at a magnetic field of 9 T and temperature as low as 2 K. This positive field-linear magnetoresistance shows no signatures of saturation....
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Permeability of sandy soils estimated from particle size distribution and field measurements
PublicationAccurate estimation of soil permeability is crucial in many geotechnical applications. Empirical and theoretical equations based on soil particle size distribution (PSD) offer a fast and cheap way for preliminary estimation of permeability in granular soils, however the results obtained from various formulas available in the literature often show significant discrepancies. While several comparative studies on this topic have been...
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Wpływ procesu redukcji na właściwości strukturalne i mechaniczne szkieł tlenkowych z grupy (Pb,Bi)-(Si,Ge)-O
PublicationW pracy zbadano wpływ procesu redukcji w wodorze prowadzonej w temperaturze 380°C na mikrostrukturę i skład pierwiastkowy próbki szkła Bi0.4Pb0.2Si0.4Ox. Wykazano, że na skutek redukcji w próbce tworzy się wyraźnie odseparowana wierzchnia warstwa o grubości ok. 50µm, która jest zubożona w tlen i charakteryzuje się lepszą przewodnością elektryczną. Stwierdzono również, że na powierzchni szkła tworzą się granule metalicznego bizmutu...
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Thermal, electrical, and magnetic properties of Fe2O3–PbO–SiO2 glass prepared by traditional melt-quenching and twin roller fast-cooling methods
PublicationIn this study, Fe–Pb–Si oxide glasses containing between 12.5 and 17.5 mol% Fe2O3 were prepared using two different methods comprising traditional melt-quenching and twin roller fast-cooling techniques. The topography and structure of the materials obtained were characterized by X-ray powder diffraction and scanning electron microscopy. All of the materials were found to be amorphous. The topography of most of the glasses comprised...
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Effect of surface on the flexomagnetic response of ferroic composite nanostructures; nonlinear bending analysis
PublicationOur analysis incorporates the geometrically nonlinear bending of the Euler-Bernoulli ferromagnetic nanobeam accounting for a size-dependent model through assuming surface effects. In the framework of the flexomagnetic phenomenon, the large deflections are investigated referring to von-Kármán nonlinearity. Employing the nonlocal effects of stress coupled to the gradient of strain generates a scale-dependent Hookean stress-strain...
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Structural studies of bismuth nanocrystals embedded in SiO2 or GeO2 matrices.
PublicationW wyniku wygrzewania w atmosferze wodoru szkieł bizmutowych i germanowych otrzymano warstwę nanogranul bizmutu w otoczeniu amorficznej matrycy oraz powierzchniową warstwę bizmutowych granul. Grubość i struktura tak otrzymanych warstw silnie zależy od czasu i temperatury redukcji.
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Materiały zmiennofazowe do stabilizowania temperatury nawierzchni asfaltowych
PublicationW artykule przedstawiono możliwość wykorzystania lekkiego kruszywa budowlanego modyfikowanego materiałem zmiennofazowym (PCM), jako dodatku do nawierzchni asfaltowej, w celu zwiększenia jej stabilności termicznej przy zachowaniu dotychczasowych właściwości mechanicznych. Cel ten może zostać osiągnięty przez nasączenie porowatych granulek lekkiego kruszywa odpowiednim materiałem zmiennofazowym, co umożliwi magazynowanie określonych...
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Mining Knowledge of Respiratory Rate Quantification and Abnormal Pattern Prediction
PublicationThe described application of granular computing is motivated because cardiovascular disease (CVD) remains a major killer globally. There is increasing evidence that abnormal respiratory patterns might contribute to the development and progression of CVD. Consequently, a method that would support a physician in respiratory pattern evaluation should be developed. Group decision-making, tri-way reasoning, and rough set–based analysis...
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Nanostruktury metalicznego bizmutu w redukowanych szkłach bizmutowo-germanianowych i bizmutowo-krzemianowych: wytwarzanie, struktura i transport nośników ładunku.
PublicationW pracy przedstawiono rezultaty badań struktury i własności transportowych szkieł bizmutowo-germanianowych i bizmutowo-krzemianowych. Potwierdzono, że przewodnictwo elektryczne jest typu jonowego. Tymi jonami są jony tlenu. Opisano związek między kolorem szkieł, a koncentracją jonów tlenu. Zbadano wpływ wygrzewania w atmosferze wodoru na własności szkieł. Opisano w sposób jakościowy i ilościowy procesy tworzenia się w wyniku redukcji...
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Low-Dimensional Magnetic Semimetal Cr0.65Al1.35Se3
PublicationWhile exploring novel magnetic semiconductors, the new phase Cr0.65Al1.35Se3 was discovered and characterized by both structural and physical properties. Cr0.65Al1.35Se3 was found to crystallize into orthorhombic CrGeTe3-type structure with space group Pnma (no. 62). Vacancies and mixed occupancies were tested, and the results show that one of the 4c sites accommodates a mixture of Cr and Al atoms, while the other 4c site is fully...
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XAFS investigations of nitrided NbN-SiO2 sol-gel derived films
PublicationPraca poświęcona jest wykorzystaniu analizy widm XAFS zmierzonych na krawędzi K atomów Nb do badania struktury cienkich warstw NbN-(100-x)SiO2 (x = 100, 80, 60 mol%) otrzymanych techniką zol-żel poprzez wysokotemperaturowe wygrzewanie warstw Nb2O5-SiO2 w atmosferze NH3. Otrzymana struktura filmu jest złożona z granul NbN ulokowanych w matrycy SiO2. Analiza XAFS pokazuje, że we wszystkich próbkach w lokalnym otoczeniu niobu znajduje...
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Impedance Studies of Phosphate-iron Glasses Containing Niobium and Titanium
PublicationThe 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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Cannabinoid CB1 antagonists and dopamine antagonists produce different effects on a task involving response allocation and effort-related choice in food-seeking behavior
PublicationW przeprowadzonych badaniach iniekcja antagonistów dopaminy (DA) szczurom powoduje znaczny spadek użycia siły przez zwierzęta w poszukiwaniu żywności i jednoczesny wzrost spożycia jedzenia laboratoryjnego. Przeciwnie, iniekcja antagonisty AM4113 lub odwrotnego agonisty AM251 receptora CB1 powoduje zmniejszenie ilości jedzenia granulek, ale nie wpływa na zwiększenie konsumpcji jedzenia laboratoryjnego. Efekty wywierane na zwierzęta...
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Manufacture and research of TPS/PE biocomposites properties
PublicationIn this paper the process of native starch preparing for modification by extrusion and manufacture of biocomposites is presented. The first aim of this study was to determine the mixing and granulating condition of native starch to obtain granulated native starch. For mixing and granulation of native starch Intensive Mixer manufactured by Maschinenfabrik Gustav Eirich was used. Mixing and granulation in a single process is a new...
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Assessment of the technological reliability of a hybrid constructed wetland for wastewater treatment in a mountain eco-tourist farm in Poland
PublicationThe aim of the present study was to assess the technological reliability of a domestic hybrid wastewater treatment installation consisting of a classic three-chambered (volume 6 m3) septic tank, a vertical flow trickling bed filled with granules of a calcinated clay material (KERAMZYT), a special wetland bed constructed on a slope, and a permeable pond used as a receiver. The test treatment plant was located at a mountain eco-tourist...
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Właściwości redukowanych szkieł Ge-Sb-O dla urządzeń termoelektrycznych
PublicationPraca zawiera wyniki badań strukturalnych oraz właściwości termoelektrycznych tlenkowego szkła antymonowo-germanianowego, poddanego redukcji w atmosferze wodoru, jako potencjalnego materiału do zastosowań w urządzeniach termoelektrycznych. Otrzymane rezultaty analizy dyfrakcyjnej oraz analizy mikroskopowej dały informacje o strukturze i składzie próbki. Potwierdziły one fakt powstawania warstwy powierzchniowej zredukowanych granul...
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Structure and electric conductivity of reduced lead-germanate, bismuth-germanate and bismuth-silicate glasses modified with potassium
PublicationZbadano szkła germanianowo-ołowiowe i krzemianowo+bizmutowe. Warstwy metalicznych granul wytwarzano w nich poprzez redukcję powierzchni w atmosferze wodoru. Praca dotyczy wpływu potasu na właściwości szkła. Przeprowadzono badania metodami mikroskopii sił atomowych, DSC oraz pomiary przewodności elektrycznej. Stwierdzono, że obecność potasu poprawia mechaniczne i technologiczne właściwości szkła.
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Improving the Quality of Magnetic Signature Reproduction by Increasing Flexibility of Multi-Dipole Model Structure and Enriching Measurement Information
PublicationThe paper presents the construction of a multi-dipole model that allows reproducing magneticsignatures of ferromagnetic objects. The virtual object used in the paper is an ellipsoid, which is the sourceof synthetic data. To make the situation more realistic, noise is added to the synthetic data. Two significantimprovements compared to previous work are presented. Three-axial magnetometers are introduced insteadof uniaxial magnetometers....
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Research of leakage magnetic field in deenergized transformer
PublicationThe article deals with the issue of the numerical analysis of the magnetic field occurring around the transformer after it has been powered down. The main goal of this analysis was to examine if it is possible to identify the residual fluxes in the transformer legs based on this fields’ measurements. It was also intended to determine the type and the location of magnetic sensors. Numerical analysis of the magnetic field was performed....
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Badania i ocena właściwości granulatu asfaltowego stosowanego w recyklingu na gorąco w otaczarkach
PublicationZaprojektowanie mieszanki mineralno-asfaltowej, zawierającej granulat asfaltowy, wymaga wiarygodnej informacji, dotyczącej jego właściwości. W artykule przedstawiono informacje dotyczące zalecanych zasad pobierania próbek granulatu oraz omówiono zakres niezbędnych badań. Przedstawiono wymagania normy EN 13108-8 oraz zasady stosowane w wybranych krajach w odniesieniu do oceny właściwości asfaltu i kruszywa zawartych w granulacie...
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Mechanical exfoliation and layer number identification of single crystal monoclinic CrCl3
PublicationAfter the recent finding that CrI3, displays ferromagnetic order down to its monolayer, extensive studies have followed to pursue new two-dimensional (2D) magnetic materials. In this article, we report on the growth of single crystal CrCl3 in the layered monoclinic phase. The system after mechanical exfoliation exhibits stability in ambient air (the degradation occurs on a time scale at least four orders of magnitude longer than...
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Synthesis and characterisation of starch cuprate
PublicationThe cupration of granular potato starch with ammonium tetrachlorocuprate(II) was performed by a 20 min lasting microwave-assisted process and by 40 min convectional heating. In both cases the degree of esterification (DE) did not exceed 0.0064. A higher dose of cuprate had a positive effect on DE, regardless of whether the microwave irradiation or the convectional heating was applied, and on the thermal stability of the starch...
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Influence of the Addition of Recycled Aggregates and Polymer Fibers on the Properties of Pervious Concrete
PublicationThe aim of the study was to check the possibility of reusing aggregate from recycled concrete waste and rubber granules from car tires as partial substitution of natural aggregate. The main objective was to investigate the effects of recycled waste aggregate modified with polymer fibers on the compressive and flexural strength, modulus of elasticity and permeability of pervious concrete. Fibers with a multifilament structure and...
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Effect of short time reduction on electrical properties of bismuth-silicate glasses
PublicationPodczas krótkiego wygrzewania szkieł bizmutowo-krzemianowych w wodorze (około 5 min w 375C) przewodnictwo powierzchniowe wzrasta o kilka rzędów wartości. Nośnikiem ładunku w tych próbkach jest hopping elektronowy między zlokalizowanymi stanami w badanej warstwie krzemu, zawierającej małe klastry Bi. Wpływ granul bizmutu na przewodnictwo jest widoczny w drugim stadium redukcji, które zachodzi po redukcji dłuższej niż 4h.
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublicationThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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Magnetic Signature Description of Ellipsoid-Shape Vessel Using 3D Multi-Dipole Model Fitted on Cardinal Directions
PublicationThe article presents a continuation of the research on the 3D multi-dipole model applied to the reproduction of magnetic signatures of ferromagnetic objects. The model structure has been modified to improve its flexibility - model parameters determined by optimization can now be located in the cuboid contour representing the object's hull. To stiffen the model, the training dataset was expanded to data collected from all four cardinal...
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublicationApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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Possibilities of Leachate Co-Treatment Originating from Biogas Production in the Deammonification Process
PublicationIn the methane fermentation process, sewage sludge is the single substrate or serves as a co-substrate with the addition of various waste products. After the treatment stable digestate is obtained, which consists of two phases solid and liquid. Liquid phase, called as a leachate, due to the high content of nutrients must be treated before they are discharged into the final receiver. Physical and chemical methods of leachate treatment...
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Electronic conductivity in the SiO2-PbO-Fe2O3 glass containing magnetic nanostructures
PublicationThe linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show...
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Electrical properties and structure of lead-borate glass containing iron ions.
PublicationThe ac and dc conductivity in iron–lead-borate glass samples was investigated in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by the means of atomic force microscopy (AFM) and the crystalline phases (if present) were identified by the means of X-ray diffractometry. Two types of ac electrical behaviour were observed. The first group of glass samples which...
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Evaluation of immune responses in sheep induced by DNA immunization with genes encoding GRA1, GRA4, GRA6 and GRA7 antigens of Toxoplasma gondii
PublicationW niniejszej pracy oszacowano odpowiedź immunologiczną owiec szczepionych domięśniowo szczepionkami DNA zawierającymi geny kodujące cztery antygeny granul o dużej gęstości (GAR1, GRA4, GRA6 oraz GRA7) Toxoplasma gondii. Wykazano, iż wykorzystanie DNA plazmidu pGRA7 indukuje znaczący poziom przeciwciał IgG-2 anty-GRA7 oraz IFN-gammma, podczas gdy iniekcja pGRA1, pGRA4 oraz pGRA6 stymuluje odpowiedź przeciwciał IgG1 z ograniczoną...