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wszystkich: 1138
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Wyniki wyszukiwania dla: continuous wavelet transform
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Intelligent monitoring the vertical dynamics of wheeled inspection vehicles
PublikacjaThe problem of intelligent monitoring of the vertical dynamics of wheeled inspection vehicles is addressed. With the independent MacPherson suspension system installed, the basic analysis focuses on the evaluation of the parameters of the so-called quarter car model. To identify a physically motivated continuous description, in practice, dedicated integral-horizontal filters are used. The obtained discrete model, which retains...
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Electrochemical Production of Sodium Hypochlorite from Salty Wastewater Using a Flow-by Porous Graphite Electrode
PublikacjaThe production of sodium hypochlorite (NaOCl) from salty wastewater using an electrochemical cell has several advantages over other methods that often require hazardous chemicals and generate toxic waste, being more sustainable and environmentally friendly. However, the process of producing sodium hypochlorite using an electrochemical cell requires careful control of the operating conditions, such as the current density, flow rate,...
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Wyznaczanie wytrzymałości betonu na podstawie funkcji dojrzałości wg amerykańskiej normy ASTM C1074-11
PublikacjaArtykuł poświęcono wyznaczaniu wytrzymałości betonu na podstawie funkcji dojrzałości wg normy ASTM C1074-11 (ang. Maturity Method). Metoda bazuje na rejestracji zmian tem - peratury w trakcie hydratacji dojrzewającego betonu. Wartykule zaprezentowano procedurę badawczą służącą wyznaczeniu funk - cji dojrzałości dla wybranej mieszanki betonowej oraz zależności wytrzymałość-dojrzałość. Celem badań jest wyznaczanie zmian w czasie...
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Odtwarzanie przebiegu trasy kolejowej o złożonym ukształtowaniu geometrycznym
PublikacjaKształt eksploatowanych torów kolejowych jest w niektórych sytuacjach bardzo złożony, a jednocześnie − jak wykazały przeprowadzone ciągłe pomiary satelitarne − niekiedy tak zdeformowany, że określenie kierunków głównych okazuje się niemożliwe.W pracy przedstawiono program komputerowy do odtwarzania przebiegu trasy kolejowej w takich właśnie przypadkach. Przygotowano zestaw funkcji realizujących połączenia prostych i łuków kołowych...
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Bypass kolejowy dla wiaduktu łukowego i kratownicowego w ciągu modernizowanej linii kolejowej E59 na odcinku Wronki – Dobiegniew
PublikacjaW artykule przedstawiono realizacje bypassu kolejowego, zlokalizowanego nieopodal miejscowości Krzyż Wielkopolski w ciągu linii kolejowej E59 na skrzyżowaniu z linią kolejową 203. Wariantowa analiza kilku zaproponowanych rozwiązań wykazała, ze wykonstruowanie bypassu na czas prowadzenia prac modernizacyjnych pozwoli na utrzymanie ciągłości ruchu kolejowego, nie stworzy nadmiernych problemów podróżnym, a jednocześnie pozwoli na...
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Positive solutions to second order four-point impulsive problems with deviating arguments
PublikacjaStosując tw. Leggetta-Williamsa, podano warunki dostateczne na istnienie dodatnich rozwiązań dla czteropunktowych problemów brzegowych dla równań różniczkowych rzędu drugiego z odchylonymi argumentami. Dyskutowane były problemy gdy argument odchylony był typu opóźnionego lub wyprzedzonego.
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Dynamic inequalities and equations of Volterra type on time scales
PublikacjaPraca dotyczy całkowo-różniczkowych równań dynamicznych typu Volterry z warunkami początkowymi. Stosując twierdzenie Banacha o punkcie stałym pokazano istnienie jedynego rozwiązania liniowego równania dynamicznego. Stosując metodę iteracji monotonicznych pokazano istnienie rozwiązań ekstremalnych dla problemów nieliniowych. Badano też nierówności dynamiczne. Praca zawiera również uwagi dotyczące zagadnień różniczkowych i różnicowych.
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Boundary value problems for dynamic equations of Volterra type on time scales
PublikacjaPraca dotyczy równań i nierówności dla problemów dynamicznych typu Volterry. Podano warunki dostateczne na istnienie ekstremalnych rozwiązań w obszarze ograniczonym przez dolne i górne rozwiązania. Praca zawiera również pewne uwagi dla konkretnych zagadnień różniczkowych i dyskretnych.
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Positive solutions to boundary value problems for impulsive second-order differential equations
PublikacjaIn this paper, we discuss four-point boundary value problems for impulsive second-order differential equations. We apply the Krasnoselskii's fixed point theorem to obtain sufficient conditions under which the impulsive second-order differential equations have positive solutions. An example is added to illustrate theoretical results.
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On integro-differential equations with delayed arguments
PublikacjaPraca dotyczy problemów różniczkowo-całkowych z warunkami początkowymi oraz brzegowymi typu okresowego. Podano warunki na istnienie i jednoznaczność rozwiązania. Badania dotyczyły również nierówności różniczkowo-całkowych z argumentami typu opóżnionego. Podano przykłady, które mogą mieć zastosowanie w problemach inżynierskich.
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Designing Intelligent Factory: Conceptual Framework and Empirical Validation
PublikacjaThis paper presents a framework for monitoring, analysing and decision making for a smart manufacturing environment. We maintain that this approach could play a vital role in developing an architecture and implementation of Industry 4.0. The proposed model has features like experience based knowledge representation and semantic analysis of engineering objects and manufacturing process. It is also capable of continuous real time...
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Hard carbon derived from rice husk as low cost negative electrodes in Na-ion batteries
PublikacjaHere, we report the synthesis of hard carbon materials (RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries. The studies show that the electrochemical properties of RHs are affected by the treatment temperatures, which determine the materials morphology, in particular, their degree of graphitization and extent of continuous channels (nanovoids). The latter...
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Estimation of a Stochastic Burgers' Equation Using an Ensemble Kalman Filter
PublikacjaIn this work, we consider a difficult problem of state estimation of nonlinear stochastic partial differential equations (SPDE) based on uncertain measurements. The presented solution uses the method of lines (MoL), which allows us to discretize a stochastic partial differential equation in a spatial dimension and represent it as a system of coupled continuous-time ordinary stochastic differential equations (SDE). For such a system...
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Online urban acoustic noise monitoring system
PublikacjaConcepts and implementation of the Online Urban Noise Monitoring System are presented. Principles of proposed solution used for dynamic acoustical maps creating are discussed. The architecture of the system and the data acquisition scheme are described. The concept of noise mapping, based on noise source model and propagation simulations, was developed and employed in the system. Dynamic estimation of noise source parameters utilized...
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A Hyperdense Semantic Domain for Discontinuous Behavior in Physical System Models
PublikacjaMultiple time models have been proposed for the formalization of hybrid dynamic system behavior. The superdense notion of time is a well-known time model for describing event-based systems where several events can occur simultaneously. Hyperreals provide a domain for defining the semantics of hybrid models that is elegantly aligned with first principles in physics. This paper discusses the value of both time models and shows how...
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Quality assessment of ZnO-based varistors by 1/f noise
PublikacjaNoise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented....
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Ceria Based Protective Coatings for Steel Interconnects Prepared by Spray Pyrolysis
PublikacjaStainless steels can be used in solid oxide fuel/electrolysis stacks as interconnects. For successful long term operation they require protective coatings, that lower the corrosion rate and block chemical reactions between the interconnect and adjacent layers of the oxygen or the hydrogen electrode. One of the promising coating materials for the hydrogen side is ceria. Using standard sintering techniques, ceria sinters at around...
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The Doppler effect in a bistatic system for determining the position of moving targets
PublikacjaThe article presents the theoretical analysis and the results of numerical calculations of the Doppler effect it occurs in a system designed to determine the position and speed of a moving target. The transmitter is the source of the signal and it emits a sinusoidal, acoustic and continuous wave. Signal reflected off a moving target is received by four hydrophones. Based on the signals, four Doppler shifts are determined and inserted...
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Quasi-discrete modelling of PMSM phase currents in drives with low switching-to-fundamental frequency ratio
PublikacjaThis study proposes a new quasi-discrete approach to modelling the permanent magnet synchronous motor (PMSM). The quasi-discrete modelling reflects the impact of continuous rotor movement, which takes place during a control cycle, on the shape of motor current waveforms. This provides much improvement in current modelling accuracy under inverter low switching-to-fundamental frequency operation. The proposed approach may be used...
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Can we rely on the pulse transit time - pressure relationship - models comparison
PublikacjaAn unobtrusive, noninvasive and continuous pressure measurement is invaluable however, still being under research and development. There are many attempts proposing an appropriate relationship between pulse pressure velocity and pressure. Fifteen different formulas, both theoretical and experimental, describing relation between blood pressure and crosssectional area of the vessel were examined. Using these formulas the relation...
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The Impact of Crushed Rock Spoil on Pitting Corrosion of Selected Stainless Steel
PublikacjaThe paper presents the results of the pitting resistance investigations of selected stainless steels in the chloride environment and the simultaneous impact of erosive factors using the cyclic polarization technique. Additionally, using electrochemical techniques, ie: electrochemical impedance spectroscopy (EIS) and measurement of corrosion potential, the behavior of the passive layer of selected stainless steels in the environment...
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Wykorzystanie fourierowskiej spektroskopii w podczerwieni do badania stężenia gazów wylotowych z tlenkowego ogniwa paliwowego zasilanego biogazem
PublikacjaW dzisiejszych czasach bardzo ważne jest pozyskiwanie energii ze źródeł odnawialnych i bezpiecznych dla środowiska. Jedną z obiecujących technologii są tlenkowe ogniwa paliwowe (ang. Solid Oxide Fuel Cell, SOFC). Stanowią one bezpieczną i ekologiczną alternatywę dla energii uzyskanej z paliw kopalnych. SOFC charakteryzuje się sprawnością energetyczną na poziomie 45-60 %, podczas gdy sprawność klasycznych elektrowni cieplnych nie...
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Analytical solution of non-stationary heat conduction problem for two sliding layers with time-dependent friction conditions
PublikacjaIn this article we conduct an overview of various types of thermal contact conditions at the sliding interface. We formulate a problem of non-stationary heat conduction in two sliding layers with generalized thermal contact conditions allowing for dependence of the heat-generation coefficient and contact heat transfer coefficient on time. We then derive an analytical solution of the problem by constructing a special coordinate...
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Intra-subject class-incremental deep learning approach for EEG-based imagined speech recognition
PublikacjaBrain–computer interfaces (BCIs) aim to decode brain signals and transform them into commands for device operation. The present study aimed to decode the brain activity during imagined speech. The BCI must identify imagined words within a given vocabulary and thus perform the requested action. A possible scenario when using this approach is the gradual addition of new words to the vocabulary using incremental learning methods....
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Novel cast polyetherurethanes based on dispersed polymeric polyols
PublikacjaOur study was focused on obtaining polyetherurethanes synthesized with using polymeric polyether based polyols differing in dispersed copolymer content (10, 20 and 40 wt%). The polyetherurethane materials were synthesized via two step method. The influence of different polymeric polyether based polyols on the chemical structure, morphology, mechanical and thermal properties of the obtained polyetherurethanes was investigated. The...
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RESOURCE ALLOCATION IN DAB+ BROADCASTING SYSTEM
PublikacjaWith over two billion receivers operating worldwide, radio transmission is by far the most accessible medium. It has been a part of our lives since the 1920’s and has become one of the most trusted and friendly mass media. Today, its popularity is still strong, despite the outcome of many electronic media. In order to transform the radio into a viable medium of the 21st century, it will have to migrate from analogue to digital...
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Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge
PublikacjaPlasma polymerized a-C:H thin films have been deposited on Si (100) and aluminum coated glass substrates by a dielectric barrier discharge (DBD) operated at medium pressure using C2Hm/Ar (m = 2, 4, 6) gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp3 and sp2 C–H stretching and...
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Mathematical modeling of hydrogen production performance in thermocatalytic reactor based on the intermetallic phase of Ni3Al
PublikacjaThe main goal of the following work is to adjust mathematical modelling for mass transfer, to specific conditions resulting from presence of chemical surface reactions in the flow of the mixture consisting of helium and methanol. The thermocatalytic devices used for decomposition of organic compounds incorporate microchannels coupled at the ends and heated to 500 oC at the walls regions. The results of the experiment were compared...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublikacjaContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Modeling, simulation, and validation of a TB41 crash test of the H2/W5/B concrete vehicle restraint system
PublikacjaThe paper addresses numerical simulations of a concrete vehicle restraint system. The model is described in detail. The advanced material law of the continuous surface cap model was used to analyze the damage locations in concrete barrier segments. The results were validated against the TB41 full-scale crash test. The test was conducted in compliance with European standard EN 1317, and the validation was performed in accordance...
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Chapter 2: Modelling and analysis of rotor with magnetic bearing system
PublikacjaThe paper is concerned with rotor magnetic bearing system modelling. Such system is a relatively complex electromechanical system and can be considered as typical mechatronic one. The port-based modelling of physical systems has been used to obtain discrete-continuous model of considered system. Proposed approach enables to obtain reduced low-order lumped parameter representation of the system including gyroscopic interactions....
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublikacjaContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Derivation of Executable Test Models From Embedded System Models using Model Driven Architecture Artefacts - Automotive Domain
PublikacjaThe approach towards system engineering compliant to Model-Driven Architecture (MDA) implies an increased need for research on the automation of the model-based test generation. This applies especially to embedded real-time system development where safety critical requirements must be met by a system. The following paper presents a methodology to derive basic Simulink test models from Simulink system models so as to execute them...
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Playing the Sprint Retrospective: A Replication Study
PublikacjaThe Sprint Retrospective is a vehicle for continuous process improvement. Even though it is a well established agile practice, running effective retrospective meetings is challenging. There have been a lot of identified problems that commonly occur during these meetings. To address them, Przybyłek & Kotecka [20] successfully revitalized retrospective meetings by adopting collaborative games, which represent a powerful tool in improving...
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Event-Triggered Communication in Cooperative, Adaptive Model Predictive Control of a Nuclear Power Plant’s Turbo–Generator Set
PublikacjaThis paper discusses the issue of optimizing the communication between the components of a cooperating control system formed by a pair of MPC controllers of a nuclear power plant turbine set using online recursive least squares identification. It is proposed to use event-triggered communication, i.e., sending information only at selected time instants, as opposed to the standard approach where communication is triggered by time...
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Weak forms of shadowing in topological dynamics
PublikacjaWe consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomor- phisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing)...
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Creating Acoustic Maps Employing Supercomputing Cluster
PublikacjaThe implemented online urban noise pollution monitoring system is presented with regard to its conceptual assumptions and technical realization. A concept of the noise source parameters dynamic assessment is introduced. The idea of noise modeling, based on noise emission characteristics and emission simulations, was developer and practically utilized in the system. Furthermore, the working system architecture and the data acquisition...
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Effects of Laser Remelting at Cryogenic Conditions on Microstructure and Wear Resistance of the Ti6Al4V Alloy Applied in Medicine
PublikacjaThe titanium and its alloys can be subjected to surface treatment, including laser treatment. In this work a new laser treatment at cryogenic conditions of Ti6Al4V alloy has been described. The work has been aimed at establishing whether such surface treatment could be suitable for implants working under wear in biological corrosive environment. The remelting has been made with the use of CO2 continuous work laser at laser power...
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Approximate Cramér–Rao bound on Doppler error in correlation-processing relatively narrowband noise radar
PublikacjaThe paper studies limitations on accuracy of Doppler estimation in continuous-wave noise radar with correlation processing. Second order properties of output of the correlation receiver are evaluated and an approximate Cram´er-Rao bound on errors of Doppler measurement is derived. The accuracy of Doppler measurements is found to be affected by the following factors: power spectral density of noise signal, frequency response of the...
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An analysis of observability and detectability for different sets of measured outputs - CSTR case study
PublikacjaA problem of proving the observability/detectability at a given measured output for non-linear biochemical systems has been addressed in this paper. A theory of indistinguishable state trajectories has been used to prove the properties of the observability or detectability of this system. It is related to taking system dynamics into consideration depending on initial conditions and the impact of inputs taking into account a given...
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The consideration to the dynamic systems parameter identification
PublikacjaIn this paper, a concept for continuous-time dynamic systems parameter identification using modulating function approach is presented. It refers to linear as well as selected non-linear systems. It shows the possibility of direct application without converting differential equation. In particular cases direct application can decrease the amount of computation in non-linear system identification, which generally requires Fourier...
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Targeting shelterin proteins for cancer therapy.
PublikacjaAs a global health challenge, cancer prompts continuous exploration for innovative therapies that are also based on new targets. One promising avenue is targeting the shelterin protein complex, a safeguard for telomeres crucial in preventing DNA damage. The role of shelterin in modulating ataxia- telangiectasia mutated (ATM) and ataxia-telangiectasia and Rad3-related (ATR) kinases, key players in the DNA damage response (DDR),...
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Receiver of Doppler multistatic system for moving target detection and tracking
PublikacjaThe article presents a method for solving major structural problems that occur in the receiver used in the multistatic Doppler system, aimed at determination of the trajectory and velocity of a moving target. In the system two transmitters emit acoustic continuous sinusoidal waves at different frequencies. The signals, scattered from a moving target are received by four hydrophones. Beside of the echoes, much larger signals coming...
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Inseparability criteria based on matrices of moments
PublikacjaInseparability criteria for continuous and discrete bipartite quantum states based on moments of annihilationand creation operators are studied by developing the idea of Shchukin-Vogel criterion Phys. Rev. Lett. 95,230502 2005. If a state is separable, then the corresponding matrix of moments is separable too. Thus, wederive generalized criteria based on the separability properties of the matrix of moments. In particular, acriterion...
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Semi complex navigation with an active optical gesture sensor
PublikacjaThis paper presents the methods of diversified touchless interactions between a user and a mobile platform utilizing the optical gesture sensor. The sensor uses 8 photodiodes to measure the reflected light in the active mode (using embedded LEDs) or it measures shadows caused by fingers in the passive mode. Several algorithms were implemented: automatic mode switching, adaptive illumination level compensation, resolution improvements...
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Thermoelectric properties of bismuth-antimony-telluride alloys obtained by reduction of oxide reagents
PublikacjaThe BieSbeTe alloys with different Bi/Sb/Te ratio were fabricated by an innovative method. For that purpose the oxide reagents were melted at high temperature, then quenched to form pellets, milled to a powder and finally reduced in hydrogen at various temperatures. Complex structures consisting of connected thin layers forming a continuous path between nano- and micrometer size grains have been obtained. The electrical conductivity,...
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Composites of tin oxide and different carbonaceous materials as negative electrodes in lithium-ion batteries
PublikacjaAbstract Tin and tin oxide have been considered as suitable materials with high theoretical capacity for lithium ion batteries. Their low cost, high safety and other technical benefits placed them as promising replacements for graphite negative electrodes. The problem to overcome with tin oxide, as well as with other metallic materials, is high volume changes during alloying/dealloying, subsequent pulverization, delamination from...
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Use of radiography images and gray level co-occurrence matrix to investigate gravitational granular flow
PublikacjaThe paper presents analysis of granular gravitational flow based on radiography images processing. The investigations were conducted for silo model geometry with concentric/eccentric discharging modes. The continuous X-ray radiography scans of granular material distribution, acquired during flow, were obtained by means of an especially designed model silo with rectangular bin and different settings of hopper angles. Image processing...
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Green analytical chemistry: Social dimension and teaching
PublikacjaGreen Analytical Chemistry (GAC) is the idea which every analytical chemist should be familiar of. Due to continuous improvement in the subject both from the aspects of theory and experimentation, the dynamic way analytical chemistry studies are evolving in the frame of chemistry degrees should not be surprising. Recently, many efforts have been made in order to include Green Chemistry principles to Education, also in the field...
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Measures of region failure survivability for wireless mesh networks
PublikacjaWireless mesh networks (WMNs) are considered as a promising alternative to wired local, or metropolitan area networks. However, owing to their exposure to various disruptive events, including natural disasters, or human threats, many WMN network elements located close to the failure epicentre are frequently in danger of a simultaneous failure, referred to as a region failure. Therefore, network survivability, being the ability...