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Search results for: MATRIX ALGEBRA
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Dependence between Ionic Liquid Structure and Mechanism of Visible-Light-Induced Activity of TiO2 Obtained by Ionic-Liquid-Assisted Solvothermal Synthesis
PublicationBecause of the tremendous structural diversityof ionic liquids (ILs), simple transfer of observations performed for one IL used for IL-TiO2 preparation on different samples is not possible. Therefore, four ionic liquids, all containing distinct nitrogen-bearing organic cations (pyridinium, pyrrolidinium, ammonium, imidazolium), were used for the first time for the preparation of IL-TiO2 composites. The role of the individual IL...
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Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis
PublicationA novel method to obtain Al2O3–ZrO2 nanocomposites is presented. It consists of the co-precipitation step of boehmite (AlO(OH)) and ZrO2, followed by microwave hydrothermal treatment at 270 ◦ C and 60 MPa, and by calcination at 600 ◦ C. Using this method, we obtained two nanocomposites: Al2O3–20 wt % ZrO2 and Al2O3–40 wt % ZrO2. Nanocomposites were characterized by Fourier transformed infrared spectroscopy, Raman spectroscopy,...
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Determination of fuel combustion product in airport runoff water samples using liquid–liquid extraction with gas chromatography–spectrometry
PublicationDetermination of xenobiotics in samples of airport runoff water is both a complex and indispensable task due to an increasing threat resulting from the activities of numerous airports. The aim of this study was to develop, optimize, and validate a procedure based on liquid–liquid extraction (LLE) coupled with gas chromatography–mass spectrometry (GC–MS) for the determination of polycyclic aromatic hydrocarbons (PAHs). So far, no...
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Use of optical skin phantoms for calibration of dermatological lasers
PublicationA wide range of dermatological diseases can be efficiently treated using laser heating. Nevertheless, before the new laser is introduced into clinical practice, its parameters and ability to interact with human skin have to be carefully examined. In order to do that optical skin phantoms can be used. Such phantoms closely imitate the scattering and absorption properties of real human skin tissue along with its thermal properties,...
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Ionic liquids-based microextraction techniques
PublicationIn recent years, the development of highly efficient analytical techniques is of great importance, however, the direct analysis of complex sample matrix is still impossible in many cases. Therefore, the step of sample preparation is commonly involved in an analytical procedure. Over the years, it has been realized that the major source of inaccuracy and imprecision on general analysis results from the operations associated to sample...
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Effect of ground tire rubber on structural, mechanical and thermal properties of flexible polyurethane foams
PublicationFlexible polyurethane foams were modified with two kinds of ground tire rubber, untreated and thermo-mechanically reclaimed. A reclamation process was performed in auto-thermal conditions, which reduced the cost of the process and decreased the environmental impact of devulcanization (e.g., emission of gases). The reclamation process was carried out in a continuous manner using a co-rotating twin screw extruder. The foams were...
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Coffee Silverskin as a Multifunctional Waste Filler for High-Density Polyethylene Green Composites
PublicationThis work aims to describe the coffee silverskin effect as a lignocellulosic waste filler for high-density polyethylene (HDPE) composites development. The main task was to determine various modification effects resulting from the complex chemical composition of coffee silverskin containing compounds with potential antioxidative properties, including caffeine, polyphenols, tannins, or melanoidins. The processing, thermal, physicochemical,...
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Method of reconstructing two-dimensional velocity fields on the basis of temperature field values measured with a thermal imaging camera
PublicationThis paper describes a novel numerical reconstruction procedure (NRP) of the velocity field during natural convective heat transfer from a two-sided, isothermal, heated vertical plate based only on the known temperature field obtained, e.g. with a thermal imaging camera. It has been demonstrated that with a knowledge of temperature distributions, the NRP enables the reconstruction of velocity fields by solving the Navier-Stokes...
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Rotational molding of polylactide (PLA) composites filled with copper slag as a waste filler from metallurgical industry
PublicationThe research work carried out so far indicates the ever wider possibilities and demand for shaping composite products in the rotational molding technology. This trend was the main reason to use waste-based filler from the metallurgical process as a filler for manufacturing polylactide (PLA)-based remolded composites. Copper slag (CS) was introduced in the single-step processing method to PLA matrix at 5, 10, 20, and 35 wt%. The...
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SPECTRAL RESPONSE OF STATIONARY JACK-UP PLATFORMS LOADED BY SEA WAVES AND WIND USING PERTURBATION METHOD
PublicationThe paper addresses non-linear vibrations of offshore jack-up drilling platforms loaded by sea waves and wind in their stationary condition using the perturbation method. Non-linearity of dynamic equations of motion for fixed offshore platforms yields from two factors. The first is load excitation generating non-linear velocity coupling in a dynamic system. This coupling is inherent in the modified Morison equation, involving the...
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A facile approach to fabricate load-bearing porous polymer scaffolds for bone tissue engineering
PublicationBiodegradable porous scaffolds with oriented interconnected pores and high mechanical are load-bearing biomaterials for bone tissue engineering. Herein, we report a simple, non-toxic, and cost-effective method to fabricate high-strength porous biodegradable scaffolds, composed of a polymer matrix of polycaprolactone (PCL) and water-soluble poly (ethylene oxide) (PEO) as a sacrificial material by integrating annealing treatment,...
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Microwave Characterization of Dielectric Sheets in a Plano-Concave Fabry-Perot Open Resonator
PublicationDespite its long history, a double-concave (DC) Fabry-Perot open resonator (FPOR) has recently gained popularity in the characterization of dielectrics in the 20–110 GHz range, mainly due to such novel accomplishments as full automation of the measurement process and the development of even ore accurate and computationally efficient electromagnetic model. However, it has been discovered that such a DC resonator suffers from unwanted...
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Highly-Miniaturized Dual-Mode Bandpass Filter Based on Quarter-Mode Substrate Integrated Waveguide with Wide Stopband
PublicationThis paper presents a novel design of a highly-miniaturized dual-mode bandpass filter (BPF) employing a quarter-mode substrate integrated waveguide (QMSIW). The QMSIW resonator is based on a square cavity with metallic vias along two sides, and open-ended edges at the remaining sides that contain orthogonal feed lines. An open slot is introduced along the two sides of the square cavity with metallic vias to form a magnetic wall....
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Structural evaluation of percolating, self-healing polyurethane–polycaprolactone blends doped with metallic, ferromagnetic, and modified graphene fillers
PublicationComposites with differently shaped micro- and nanofillers show various, unique thermal, and physicochemical properties when mixed with carefully chosen polymer matrix. Selected composition holds strategic value in achieving desired properties that is biodegradability, thermoelectric conductivity, and shape memory for organic coating. The main aim of this work is to briefly examine structural changes after reaching percolation threshold...
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Electrochemical oxidation of PFOA and PFOS in landfill leachates at low and highly boron-doped diamond electrodes
PublicationPolyfluorinated alkyl substances (PFASs) may reach landfill leachates (LLs) due to improper waste management. In this study perfluorooctanoate (PFOA) and perfluorooctane sulphonate (PFOS) were used as representatives of PFASs in the decomposition on boron-doped diamond electrodes (BDDs) with high (10k ppm) and low (0.5k ppm) boron doping concentrations. The result shows that although better COD removal efficacies are obtained on...
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Development of novel optoelectronic sensory structures utilising colour centres in nanodiamonds and their interactions with analytes
PublicationThe goal of this dissertation was to develop and assess surface modifications of fluorescent nanodiamonds (NDs) for optical sensing. Three modification routes were tested, each aimed at a different application. Modification with poly-L-lysine (pLys) was verified for optical sensing of pH via an interrelationship between electrically negative (NV¯) and neutral (NV0) nitrogen-vacancy centres. Immobilisation of Ochratoxin A (OTA),...
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Increasing the conductivity of V2O5-TeO2 glass by crystallization: structure and charge transfer studies
PublicationIn the present paper, V 2 O 5 -TeO 2 glass was prepared by the melt-quenching technique. Crystallization of glass with a vanadium content higher than 35%mol results in an increase in electrical conductivity by a few orders of magnitude and a decrease in activation energy from ~0.40 to ~0.12 eV. In this work, a critical review of existing charge transfer models was presented on the example of V 2 O 5 -TeO 2 glass and glass–ceramics....
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Broad Stopband, Low-Loss, and Ultra-Compact Dual-Mode Bandpass Filter Based on HMSIRC
PublicationIn this investigation, an ultra-compact dual-mode bandpass filter (BPF) with a wide stopband re-sponse is realized by using a half-mode substrate-integrated rectangular cavity (HMSIRC). The HMSIRC resonator is designed with a cavity that is rectangular in shape and has metallic vias along three of the sides. The fourth side is open-ended and contains microstrip feed lines. For the purpose of constructing a magnetic wall, a rectangular...
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Unveiling the Pool of Metallophores in Native Environments and Correlation with Their Potential Producers
PublicationFor many organisms, metallophores are essential biogenic ligands that ensure metal scavenging and acquisition from their environment. Their identification is challenging in highly organic matter rich environments like peatlands due to low solubilization and metal scarcity and high matrix complexity. In contrast to common approaches based on sample modification by spiking of metal isotope tags, we have developed a two-dimensional...
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Fabrication of the cross-linked PVA/TiO2/C nanocomposite membrane for alkaline direct methanol fuel cells
PublicationA crosslinked Poly(vinyl alcohol) based composite membrane was developed through a phase inversion process for use in alkaline direct methanol fuel cells (ADMFCs). The titanium dioxide (TiO2) and carbon nanoparticles (NPs) have been incorporated into the PVA polymer matrix to improve the mechanical and thermal properties. The membrane samples were further modified with maleic acid, a carboxylic acid acting as the cross-linker,...
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CHEMOTHERAPY-MEDIATED COMPLICATIONS OF WOUND HEALING. AN UNDERSTUDIED SIDE EFFECT
PublicationSignificance: Chemotherapy is a primary method to treat cancer, but while cytotoxic drugs are designed to target rapidly dividing cancer cells, they can also affect other cell types, including dermal cells and macrophages involved in wound healing, which often leads to the development of chronic wounds. The situation becomes even more severe when chemotherapy is combined with surgical tumor excision. Recent advances: Despite its...
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Lanthanide ions (Eu3+, Er3+, Pr3+) as luminescence and charge carrier centers in Sr2TiO4
PublicationA series of strontium orthotitanate (Sr2TiO4) samples doped with 2% of a mole of europium, praseodymium, and erbium were obtained using the solid-state synthesis method. The X-ray diffraction (XRD) technique confirms the phase purity of all samples and the lack of the influence of dopants at a given concentration on the structure of materials. The optical properties indicate, in the case of Sr2TiO4:Eu3+, two independent emission...
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Naturally-derived hydrogels for 3D pancreatic tumor models: A short review
PublicationStatistics suggest a high proportion of mortality rate by pancreatic cancer, which is a solid tumor characterized by high heterogeneity and the presence of a complex extracellular matrix. The very low effectiveness of pancreatic cancer treatment roots in the high metastatic potential and drug resistance of this tumor. Therefore, the quest for efficient cellular models enabling precise mimicking in vivo conditions, and anticancer...
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Mater-Bi/Brewers’ Spent Grain Biocomposites—Novel Approach to Plant-Based Waste Filler Treatment by Highly Efficient Thermomechanical and Chemical Methods
PublicationThermoplastic starch (TPS) is a homogenous material prepared from native starch and water or other plasticizers subjected to mixing at a temperature exceeding starch gelatinization temperature. It shows major drawbacks like high moisture sensitivity, poor mechanical properties, and thermal stability. To overcome these drawbacks without significant cost increase, TPS could be blended with bio-based or biodegradable polymers and...
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The presence of polycyclic aromatic hydrocarbons in disposable baby diapers: A facile determination method via salting-out assisted liquid-liquid extraction coupled with gas chromatography-mass spectrometry
PublicationIn this paper we demonstrate the development of the extraction procedure of polycyclic aromatic hy- drocarbons from baby diapers along with their quantification by gas chromatography-mass spectrometry. Apart from covering plastic foil, disposable baby diapers contain sorbents intended to absorb urine and feces. A hygroscopic, adsorptive, and tough-to-homogenize fibrous sorbent, represents an analytical chal- lenge to analytical...
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Implementing SP4CE Learning Rooms concept and AUTODESK online certification in the preparation of a new generation of engineers.
PublicationIn academia, educators do not always cope with rapidly changing technologies. Yet keeping up with new trends is essential to graduates’ success in a competitive job market. In the article, the author will answer the question of how Autodesk University Open Educational Resources and Certiport exams including GMetrix can enhance students’ academic progress and prepare them for future career. The concept of co-operation between Authorized...
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Elementy kwantowego modelu obliczeń i algorytmiki kwantowej : łagodne wprowadzenie do informatyki kwantowej
PublicationJuż dziś wiadomo, że z chwilą udanej realizacji komputera kwantowego maszyna ta będzie pozwalała na znajdowanie rozwiązań problemów obliczeniowych leżących poza zasięgiem komputerów klasycznych. Opracowano szereg algorytmów kwantowych, z których największą sławą cieszy się procedura Shora, pozwalająca efektywnie dokonywać tzw. faktoryzacji, tj. rozkładu bardzo dużych liczb naturalnych na czynniki pierwsze. Na trudności obliczeniowej...
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MODELOWANIE WYBRANYCH MIAR BEZPIECZEŃSTWA RUCHU NA DŁUGICH ODCINKACH DRÓG
PublicationKażdego roku w wypadkach drogowych na świecie życie traci prawie 1,3 mln osób, co oznacza prawie niemal 3 tys. ofiar dziennie,. Tyle samo zabitych w ruchu drogowym odnotowujemy rocznie w Polsce. Ekonomiczne straty w wyniku tych wypadków wynoszą ok. 2% światowego PKB. W roku 2010 Organizacja Narodów Zjednoczonych (ONZ) przyjęła rezolucję pt. „Dekada działań na rzecz bezpieczeństwa ruchu drogowego na lata 2011 – 2020” rozpoczynającą...
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Analiza właściwości rozszerzonego obserwatora prędkości maszyny indukcyjnej
PublicationRozszerzony obserwator prędkości został zaproponowany przez prof. Krzemińskiego i jest oparty na rozszerzonym modelu maszyny indukcyjnej, gdzie wprowadzona został nowa zmienna ζ. Jest to nowe podejście do estymacji zmiennych stanu maszyny indukcyjnej i nie wszystkie problemy zostały do tej pory rozwiązane. Zaproponowano wykorzystanie algorytmów ewolucyjnych do doboru wzmocnień obserwatora. W celu redukcji nakładów obliczeniowych...
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Long-distance quantum communication over noisy networks without long-time quantum memory
PublicationThe problem of sharing entanglement over large distances is crucial for implementations of quantum cryptography. A possible scheme for long-distance entanglement sharing and quantum communication exploits networks whose nodes share Einstein-Podolsky-Rosen (EPR) pairs. In Perseguers et al. [Phys. Rev. A 78, 062324 (2008)] the authors put forward an important isomorphism between storing quantum information in a dimension D and transmission...
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Comparative Analysis of Text Representation Methods Using Classification
PublicationIn our work, we review and empirically evaluate five different raw methods of text representation that allow automatic processing of Wikipedia articles. The main contribution of the article—evaluation of approaches to text representation for machine learning tasks—indicates that the text representation is fundamental for achieving good categorization results. The analysis of the representation methods creates a baseline that cannot...
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Porty jachtowe - mariny. Projektowanie.
PublicationKsiążka poświęcona jest zasadom projektowania portów jachtowych oraz marin. Definiuje poszczególne zagadnienia projektowania i eksploatacji portów jachtowych oraz przedstawia matody obliczeń konstrukcji przewidzianych do postoju jachtów jak pomosty stałe i pływające. Ponadto przedstawia propozycję obliczania i wymiarowania falochronów pływających oraz zasady przyjmowania wyposażenia portów.
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Liquid membrane oscillators
PublicationZaprezentowano krótki przegląd różnych podejść do opisu mechanizmu oscylacji róznicy potencjału elektrycznego między fazami wodnymi. Więcej uwagi zwrócono na mechanizm zaproponowany w zespole Szpakowskiej. Dla układu z kationowym surfaktantem nagła adsorpcja i desorpcja cząsteczek surfaktantu na granicy faza akceptorowa/ membrana ciekła poprzedzona dyfuzją jest odpowiedzialna za obserwowane oscylacje. W przypadku układu z anionowym...
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Endangering of Groundwater on the Municipal Intakes in Gdańsk
PublicationGroundwater from the Quaternary aquifer on the marine terrace in Gdańsk has been exploited for almost a century, supplying the town with water of good quality. However intensive exploitation in the past and development of the urban area influenced the chemical composition of the water. Hydrogeochemical background for such ions as chlorine, sulphate and ammonia has changed and also some organic micro compounds appeared in single...
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Gdynia - a New City of the Twenties and Thirties
PublicationArtykuł jest pierwszym przedstawieniem w zagranicznym, anglojęzycznym czasopiśmiennictwie dziejów budowy nowego miasta lat dwudziestych i trzydziestych XX w, jakim był Gdynia. Przedstawiona została geneza decyzji o budowie portu i miasta, pierwsze plany urbanistyczne w kontekście projektów portu, a także rozwój architektoniczny Gdyni. W szczególności zaś przedstawiono przemiany stylowe gdyńskiej architektury modernistycznej tego...
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Modern Movement in Gdynia and in Europe: Inspirations and Analogies
PublicationModernism in Gdynia finds its roots in the European Architecture of 1920s and 1930s. The main centres of the style are such artistic capitals as Paris, Berlin, Wien, Amsterdam, Rotterdam, Brussels, Stuttgard and Hamburg. The article points out the connections between the famous European edifeces of those times and the architecture of Gdynia.
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Dzielnica reprezentacyjna Gdyni
PublicationKoncepcja Dzielnicy Reprezentacyjnej Gdyni ma historię tak długą jak samo miasto. Już pierwsze plany urnanistyczne z 1926 r. przewidywały jej budowę na południe od portu, jednakże później uległy one zmianie. Szeroko dyskutowany i bardzo interesujący projekt tej dzielnicy powstał w 1938 r., lecz zdołano zaledwie rozpocząć jego realizację przed 1939 r. Projekt ten po wojnie zarzucony odradza się w innym kształcie w czasach współczesnych.
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Style w gdyńskiej architekturze okresu międzywojennego
PublicationKrótki okres międzywojenny był jednak czasem narodzin nowej zupełnie formacji stylowej - modernizmu. Stąd też w architekturze gdyńskiej widzimy wielość konwencji związanych z odchodzącym w przeszłość historyzmem i narodzinami nowego języka artystycznego. Artykuł daje krótki przegląd tej problematyki.
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Modernizm gdyński - modernizm europejski. Inspiracje i analogie
PublicationModernizm gdyński znajduje swe wyraźne korzenie w nurtach architektury europejskiej okresu międzywojennego.Głównymi ośrodkami kształtowanie się tych nurtów były artystyczne stolice europejskie, takie jak Paryż, Berlin, Wiedeń, Amsterdam, Rotterdam,Bruksela, Stuttgard i Hamburg. Artykuł wskazuje na analogie między wybitnymi realizacjami europejskimi a architekturą gdyńskiego moderizmu.
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Kamienna Góra - od letniska-ogrodu do modernistycznej dzielnicy Gdyni
PublicationKamienna Góra jest dziś willową dzielnicą Gdyni. Jej układ urbanistyczny powstał na potrzeby podgdyńskiego letniska w 1920 r. Wówczas też nadano jej kształt architektoniczny, który przedefiniowano w sensie stylowym na początku lat trzydziestych w duchu modernistycznym. Dziś jednak w ten krajobrazowy układ wdziera się coraz agresywniej współczesna zabudowa, burząc przy tyn skalę i charakter zabytkowego założenia.
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Wpływ urbanizacji na wykorzystanie wód podziemnych na tarasie nadmorskim w Gdańsku.
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Inspiracje międzywojenne we współczesnej architekturze Gdyni
PublicationWspółczesna architektura Gdyni ma swą wyraźną specyfikę. Wynika to w dużym stopniu z faktu, że jest ona w sposób dość czytelny inspirowana architekturą dwudziestolecia międzywojennego. Od czasu gdy na początku lat 90-tych XX w. etos lat międzywojennych został "odzyskany" i ponownie odkryty w świadomości społecznej, realizacje architektoniczne tamtego okresu zaczęły funkcjonować jako swoiste wzory.W artykule pokazano współczesne...
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Zjawiska oscylacyjne w układach membranowych
PublicationOmówiono wybrane zjawiska oscylacyjne występujące w układach homogenicznych i heterogenicznych, ze szczególnym uwzględnieniem oscylatorów membranowych. Wśród nich szerzej omówiono oscylator Teorella składający się z membrany porowatej oraz oscylator z membraną ciekłą i kationowym surfaktantem, które mogą stanowić sztuczne modele złożonych procesów biologicznych. Przedstawiono założenia mechanizmu oscylacji opartego na kinetyce...
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Przestrzeń publiczna a przestrzeń prywatna w strukturze gdyńskiej kamienicy okresu międzywojennego
PublicationKamienica jest jednym z najbardziej charakterystycznych typów zabudowy miejskiej. Stanowi ona ten rodzaj domu mieszkalnego, który -będąc w sensie własnościowym elementem przestrzeni prywatnej - jest jednocześnie w sensie wizualnym i funkcjonalnym elementem przestrzeni publicznej. Dzieje się tak przede wszystkim z uwagi na jej rolę w strukturze miasta - rolę elementu pozostającego na styku obu tych stref. Przedstawienie interakcji...
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OTWARTE DANE BADAWCZE: SONDAŻOWA ANALIZA DOŚWIADCZEŃ I POTRZEB PRACOWNIKÓW UNIWERSYTETU IM. ADAMA MICKIEWICZA W POZNANIU
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The Conditions of Measuring Local Government Units Expenditure Efficiency
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Openess and Transparency of Fiscal Reporting in Poland – Assessment and Recommendation
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The Hidden Local Debt – Reasons, Effects, Countermeasure
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Działania służące i niesłużące efektywnemu zarządzaniu długiem jednostek samorządu terytorialnego
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Jawność i przejrzystość sprawozdawczości jednostek samorządu terytorialnego – ocena i rekomendacje
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