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Finite Element Method Applied in Electromagnetic NDTE: - A Review
PublikacjaThe paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority...
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Probabilistic sensitivity of limit states of structures : The Monte Carlo simulation
PublikacjaThe main issue of the paper is the probabilistic sensitivity of the limit states of structures with respect to selected input design variables. Attempt to the problem is done by the dedicated Monte Carlo simulation procedure. Basic design variables are random variables of given probability distributions, presented in the form of random numbers. Uni-parametrical increment of the dominant basic variable (basic variables) is done,...
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Resistant to correlated noise and outliers discrete identification of continuous non-linear non-stationary dynamic objects
PublikacjaIn 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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Resistant to correlated noise and outliers discrete identification of continuous non-linear non-stationary dynamic objects
PublikacjaIn this study, dedicated 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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Delivery of Ancillary Services in Distribution Power Systems
PublikacjaOne of the technical and organizational challenges the power system faces in deregulated market conditions is to organize an ancillary services market. The growing share of distributed generation of variable (intermittent) energy sources and a change in the market position of consumers, causes the demand for distributed delivery of ancillary services. For this purpose, it is sought to use the ability of the regulatory measures:...
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Low-fidelity model considerations for simulation-based optimisation of miniaturised wideband antennas
PublikacjaHere, variable-fidelity electromagnetic (EM)-based design optimisation of miniaturised antennas is discussed. The authors focus on an appropriate selection of discretisation density of the low-fidelity EM model, which results in good performance of the optimisation algorithm in terms of its computational complexity and reliability. Trust-region gradient search with low-fidelity model corrected by means of non-linear frequency scaling...
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The analysis of firms’ involvement in internationalisation and determinants of its intensity – an analysis for developing and post-transition economies
PublikacjaThe study presents the empirical analysis of firms’ involvement in different forms of internationalisation: export, indirect export, import, indirect import and finally simultaneous exporting and importing. The analysis is based on firm-level data from the World Bank Enterprise Survey (March 2017 release). The empirical part is divided into two stages. Firstly account is taken of firms’ heterogeneity and then a Melitz type analysis...
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Homoclinics for singular strong force Lagrangian systems in R^N
PublikacjaWe will be concerned with the existence of homoclinics for second order Hamiltonian systems in R^N (N>2) given by Hamiltonians of the form H(t,q,p)=Φ(p)+V(t,q), where Φ is a G-function in the sense of Trudinger, V is C^2-smooth, periodic in the time variable, has a single well of infinite depth at a point ξ and a unique strict global maximum 0 at the origin. Under a strong force type condition aroud the singular point ξ, we prove...
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Structural Reliability Assessment Of Corroded Tanker Ship Based On Experimentally Estimated Ultimate Strength
PublikacjaThis work deals with the reliability assessment of a tanker ship hull structure subjected to a vertical bending moment and corrosion degradation. The progressive collapse and ultimate load carrying capacity are estimated based on experimentally tested scaled box-shaped-specimens. The translation of the strength estimate of the scaled specimen to the real tanker ship hull structure is performed based on the dimensional theory developing...
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Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
PublikacjaThe aim of the present paper is to show the results of the shaking table experimental study concerning the diagnosis of damage in a model of cylindrical steel tank with self-supported roof which is filled with liquid. During the tests, the base of the structure was excited under the harmonic loading with variable frequency. The tests were repeated for different stages of damage, which was introduced in the model by easing the bolts...
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Dynamic analysis of temporary steel grandstand equipped with different types of bracing system
PublikacjaIn the paper, behaviour of a temporary steel grandstand equipped with two different types of bracing system has been analysed through the numerical study. A typical solution concerning application of a diagonal tubular members has been compared with elements proposed by authors and called polymer dampers. A polymer element consists of two L-shape steel members bonded with polymer mass. The aim of the paper is to verify the effectiveness...
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Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide
PublikacjaThe paper presents results of theoretical and numerical investigation of guided wave propagation in two-layer bars with geometric imperfections in the form of eccentric location of steel core. Steel rod of diameter equal to 1 cm embedded in composite mortar-type cover with external diameter equal to 5 cm has been taken into consideration. Several different rods with variable size of eccentricity are analysed. Results for rods with...
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Diffusion equations with spatially dependent coefficients and fractal Cauer-type networks
PublikacjaIn this article, we formulate and solve the representation problem for diffusion equations: giving a discretization of the Laplace transform of a diffusion equation under a space discretization over a space scale determined by an increment h > 0, can we construct a continuous in h family of Cauer ladder networks whose constitutive equations match for all h > 0 the discretization. It is proved that for a finite differences discretization...
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The Belt and Road Initiative and export variety: 1996–2019
PublikacjaThis study examines the association between the Belt and Road Initiative (BRI) and export variety (EV). We propose three hypotheses on how BRI may foster export markets (destinations) or export product lines. The estimates are based on a dataset constructed specifically for this analysis, covering 183 countries and linked with trade data from 1996 to 2019. We apply the instrumental variable (IV) approach in regressions for covering the...
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Optymalizacja efektywności hamowania odzyskowego w transporcie szynowym przez sterowanie czasem przyjazdu na stację
PublikacjaArtykuł nawiązuje do poprzednich prac autorów, w których przedstawiono model organizacji ruchu kooperujących pociągów z uwzględnieniem optymalizacji wykorzystania energii zwracanej do sieci jezdnej. W przedstawionej pracy zmodyfikowano model zmieniając główną zmienną sterującą, mającą wpływ na efektywne wykorzystanie energii, z czasu odjazdu na czas przyjazdu pociągu na stację lub przystanek. Optymalizacja dokonywana jest przez...
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The role of ergonomics in architectonic and marketing operations
PublikacjaThe 20th century, along with the development of mass culture, brought a rapid increase of marketing communications significance. At first, this branch of art had an informational function associated with advertising operations. Nowadays, an increase of marketing specialists’ interest in influencing a human being by the space they stay in may be observed. Ergonomics plays an important role in such operations. The aim of this article...
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Modern Platform for Parallel Algorithms Testing: Java on Intel Xeon Phi
PublikacjaParallel algorithms are popular method of increasing system performance. Apart from showing their properties using asymptotic analysis, proof-of-concept implementation and practical experiments are often required. In order to speed up the development and provide simple and easily accessible testing environment that enables execution of reliable experiments, the paper proposes a platform with multi-core computational accelerator:...
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Sensorless induction motor drive with voltage inverter and sine-wave filter
PublikacjaThis paper presents a speed sensorless control system of an induction motor with an output LC filter. It is known that the parameters design of the filter gives sine wave motor supply voltage but complicates control and estimation process. The reason is that the voltage drop and phase shift between filter input and output signals are imposed, and hence the motor voltages and currents differ from the inverter output waveforms. To...
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Simulation of large thrust-bearing performance at transient states, warm and cold start-up
PublikacjaThe start-up of a large hydrodynamic thrust bearing of a vertical hydrogenerator is one of the most critical situations during the lifetime of a bearing. Hydrodynamic load capacity is low due to low speed and higher thermal deformations of the pad. A new approach to the simulation of a hydrodynamic bearing is shown in this article. A combination of finite elements method and computational fluid dynamics is used to perform the transient...
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Performance evaluation of the parallel object tracking algorithm employing the particle filter
PublikacjaAn algorithm based on particle filters is employed to track moving objects in video streams from fixed and non-fixed cameras. Particle weighting is based on color histograms computed in the iHLS color space. Particle computations are parallelized with CUDA framework. The algorithm was tested on various GPU devices: a desktop GPU card, a mobile chipset and two embedded GPU platforms. The processing speed depending on the number...
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Continuous wave sonar with hyperbolic frequency modulation keyed by pseudo-random sequence
PublikacjaA CW FM type sounding signal is used in the classical solution of silent sonar. While the signal provides a relatively simple implementation of digital signal processing, and ensures good detection conditions, unfortunately, in the presence of the Doppler effect, distance measurement results tend to be wrong. This is due to the fact that the received signal’s instantaneous frequency value is dependent both on the distance to the...
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Extended duration running and impulse loading characteristics of an acoustic bearing with enhanced geometry
PublikacjaThis paper presents performance during prolonged running of the acoustic bearing when PZTs are switched off and when they are switched on. The effect of active PZT on shaft’s displacements in X and Y directions is clearly demonstrated. Performance of the acoustic bearing was also assessed when an impulse force was applied to the running shaft at speed. Once again the benefits of having PZTs active are beyond doubt. The instability...
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A correlation between electron-hole pair radii and magnetomodulation of exciplex fluorescence in electron donor-electron acceptor organic systems
PublikacjaElectric field dependencies of electromodulated photoluminescence and magnitudes of the magnetic-field effect on photoluminescence havebeen measured in vacuum-evaporated films of m-MTDATA [4,4',4"-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine]:bathophe-nanthroline, m-MTDATA:BCP (bathocuproine), as well as 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine:BCP. The Sano-Tachiya-Noolandi-Hong extension of standard Onsager...
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Feedback Control of Multiphase Induction Machines with Backstepping Technique
PublikacjaThe paper presents the control possibility of five phase induction machines. In the proposed solution the machine model vector form is not transformed to the (dq)-coordinate system, that is connected to rotor flux vector, but utilizes the stationary system ( αβ ). Moreover, the nonlinear model linearization is based on demonstrated nonlinear variables transformation for i-orthogonal ( αβ )(n) planes. By introducing the backstepping...
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The role of water in deep eutectic solvent-base extraction
PublikacjaDeep eutectic solvents (DESs) are currently being used in different sectors, such as electrochemistry, electrodeposition, organic synthesis, nanoparticle preparation, bioactive compound separation, etc. Their use in analytical chemistry has only recently begun to expand. Despite the publication of a sufficient number of DES-based analytical extraction procedures, some details, such as interaction of DESwith the sample and target...
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Experimental study of the multi-disc negative brake for a hydraulic motor
PublikacjaThis paper describes the methodology for experimental testing of a multi-disc brake. The construction of this brake was also present. The brake is dedicated to hydraulic motors with a small working volume. Experimental tests were carried out on a brake with plates immersed in oil and, for comparison, tests were carried out on a dry brake. As a result of the tests, the permissible torque (load) that is able to transfer the brake...
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Flow Control Algorithm for UMTS HSDPA
PublikacjaHSDPA (High Speed Downlink Packet Access) jest istotnym etapem ewolucji systemu UMTS. Pozwala na transmisję do użytkownika z prędkością dochodzącą do 14.4 Mbit/s; aby to umożliwić, wprowadzono w wersji 5 UMTS szereg nowych mechanizmów w warstwie fizycznej oraz MAC. W tej pracy przedstawiono szczegółową analizę jednego z nowych mechanizmów - algorytmu kontroli natężenia ruchu między MAC-hs i MAC-d. Zaproponowano nowy, efektywny...
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China’s international trade and global value chains under One-Belt One-Road initiative
PublikacjaResearch background: After China acceded to the WTO in 2001, its foreign trade has expanded rapidly to be the largest share in the world. However, China's economic development changing from high-speed growth to medium high-speed growth in recent years. At the same time, the increase in labour cost and overcapacity also hinder China’s international trade. In order to solve these challenges and strengthening ties...
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Pedestrian Safety at Midblock Crossings on Dual Carriageway Roads in Polish Cities
PublikacjaRoad crossings across two or more lanes in one direction are particularly dangerous due to limited sight distance and high vehicle speeds. To improve their safety, road authorities should provide safety treatments. These may include additional measures to reduce speed and narrow the road cross-section and the introduction of active pedestrian crossings. Equipped with flashing lights activated automatically when a pedestrian is...
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Towards Designing an Innovative Industrial Fan: Developing Regression and Neural Models Based on Remote Mass Measurements
PublikacjaThis article presents the process of the construction and testing a remote, fully autonomous system for measuring the operational parameters of fans. The measurement results obtained made it possible to create and verify mathematical models using linear regression and neural networks. The process was implemented as part of the first stage of an innovative project. The article presents detailed steps of constructing a system to...
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Ecological bearing systems for water turbines – research and development at Gdansk University of Technology
PublikacjaIncreasing requirements for environmental protection make it necessary to introduce new materials and designs. Hydroelectric power plants operating in direct contact with water reservoirs and rivers are potentially endangering water cleanliness, hence they should also be modernized in the way minimizing the environmental hazards. A lot of progress in this field has been achieved in last decades, but still there is much work to...
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Application of the Fractional Fourier Transform for dispersion compensation in signals from a fiber-based Fabry-Perot interferometer
PublikacjaOptical methods of measurement do not require contact of a probe and the object under study, and thus have found use in a broad range of applications such as nondestructive testing (NDT), where noninvasive measurement is crucial. Measuring the refractive index of a material can give a valuable insight into its composition. Low‑coherence radiation sources enable measurement of the sample’s properties across a wide spectrum, while...
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Multistatyczny, Dopplerowski System określania położenia i prędkości ruchomych celów w wodzie
PublikacjaW omawianym w pracy multistatycznym, dopplerowskim systemie określania położenia i prędkości ruchomych celów w wodzie źródłem sygnału są dwa nadajniki emitujące sinusoidalne, akustyczne fale ciągłe o różnych częstotliwościach, które po odbiciu od ruchomego celu są obierane przez cztery hydrofony. W artykule przedstawiono analize teoretyczna efektu Dopplera, na którym oparte jest działanie systemu oraz metodę rozwiązania głównych...
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Problemy zagrażające bezpieczeństwu dzieci i ich rodziców w ruchu drogowym podczas podróży do szkoły na przykładzie Przymorza Małego w Gdańsku
PublikacjaArtykuł opisuje problemy wpływające negatywnie na bezpieczeństwo ruchu drogowego na obszarze Przymorza Małego, a także przedstawia pomysły, których realizacja powinna poprawić bezpieczeństwo pieszych, rowerzystów oraz kierowców pojazdów samochodowych poruszających się po tym obszarze. W pierwszej części przedstawiono informacje dotyczące stanu aktualnego analizowanego terenu, opisano zlokalizowane tutaj placówki oświatowe, a także...
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Fractional Order Dynamic Positioning Controller
PublikacjaImproving the performance of Dynamic Positioning System in such applications as station keeping, position mooring and slow speed references tracking requires improving the position and heading control precision. These goals can be achieved through the improvement of the ship control system. Fractional-order calculus is a very useful tool which extends classical, integer-order calculus and is used in contemporary modeling and control...
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An Analog Sub-Miliwatt CMOS Image Sensor With Pixel-Level Convolution Processing
PublikacjaA new approach to an analog ultra-low power medium-resolution vision chip design is presented. The prototype chip performs low-level image processing algorithms in real time. Only a photo-diode, MOS switches and two capacitors are used to create an analog processing element (APE) that is able to realize any convolution algorithm based on a full 3x3 kernel. The proof-of-concept circuit is implemented in 0.35 µm CMOS technology,...
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Diffusible hydrogen management in underwater wet self-shielded flux cored arc welding
PublikacjaThis article reports the effect of underwater wet welding parameters and conditions on the diffusible hydrogen content in deposited metal for welding with a self-shielded flux cored wire. The diffusible hydrogen content in deposited metal was determined using the glycerin method according to the Plackett-Burman design determining the significance of the effect of the stick out length, welding current, arc voltage, travel speed...
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Optimization of chip removing system operation in circular sawing machine
PublikacjaThe paper presents the optimization of the wood chips removing system in the sliding table saw. Chips are generated during the cutting of the material. The attention was focused on the upper casing of mentioned system. The methodical experimental studies of the pressure distribution inside the casing during the wood chip removing operation for the selected rotational speed of saw blade with a diameter of 300 mm and 450 mm were...
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Analysis of Denoising Autoencoder Properties Through Misspelling Correction Task
PublikacjaThe paper analyzes some properties of denoising autoencoders using the problem of misspellings correction as an exemplary task. We evaluate the capacity of the network in its classical feed-forward form. We also propose a modification to the output layer of the net, which we called multi-softmax. Experiments show that the model trained with this output layer outperforms traditional network both in learning time and accuracy. We...
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SELECTED COMBINED POWER SYSTEMS CONSISTED OF SELFIGNITION ENGINE AND STEAM TURBINE
PublikacjaThis paper presents optimization of selected combined diesel engine-steam turbine systems. Two systems: the system combined with waste heat one-pressure boiler only and its version containing additionally low-pressure boiler proper feeding degasifier and the system of two-pressure cycle, were taken into considerations. Their surplus values of power output and efficiency associated with utilization of waste heat contained in piston...
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Augmented Reality for Privacy-Sensitive Visual Monitoring
PublikacjaThe paper presents a method for video anonymization and replacing real human silhouettes with virtual 3D figures rendered on the screen. Video stream is processed to detect and to track objects, whereas anonymization stage employs fast blurring method. Substitute 3D figures are animated accordingly to behavior of detected persons. Their location, movement speed, direction, and person height are taken into account during the animation...
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An assessment of teeth quality of the mini gang saw blade
PublikacjaIn this work, the assessment of the effect of the operating time (90 min.) of the mini gang saw blades during sawing Scotch pine (Pinus sylvestris L.) samples upon changes of the saw blade teeth sharpness (bluntness), which was defined as an effective radius of the nose ρ , has been described. The research activities have been carried out on the Nikon Ti-S optical microscope equipped with the Nikon DS-30W camera allowing high-speed...
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On power stream in motor or drive system
PublikacjaIn a motor or in a drive system the quantity of power increases in the direction opposite to the direction of power flow. Energy losses and energy efficiency of a motor or a drive system must be presented as functions of physical quantities independent of losses. Such quantities are speed and load. But the picture of power stream in a motor or in a drive system is presented in the literature in the form of traditional Sankey...
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Disturbances of Earth magnetic field caused by eddy currents of airplane
PublikacjaThe uniform magnetic field of the Earth in the surrounding of a mobile, metallic object undergoes deformation by eddy currents. The influence of the moving, conducting object on the Earth's total magnetic field depends on the object's shape, position and speed of the changes relative to the magnetic field vector of the Earth, as well as the electric conductivity and the relative magnetic permeability of the material. Disturbances...
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Multi-objective Weather Routing with Customised Criteria and Constraints
PublikacjaThe paper presents a weather routing algorithm utilising a multi-objective optimisation with constraints, namely the Multi-objective Evolutionary Weather Routing Algorithm (MEWRA). In the proposed approach weather route recommendations can be made simultaneously e.g. for passage time, fuel consumption and safety of passage by means of Pareto optimisation. The sets of criteria and constraints in the optimisation process are fully...
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Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
PublikacjaInfluence 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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Water-mediated long-range interactions between the internal vibrations of remote proteins
PublikacjaIt is generally acknowledged that the mobility of protein atoms and the mobility of water molecules in the solvation layer are connected. In this article, we answer the question whether a similar interdependence exists between the motions of atoms of proteins separated by the hydration layers of variable thickness. The system consisted of a kinesin catalytic domain and a tubulin dimer. It was studied using molecular dynamics simulations....
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Understainding solid-phase microextraction: key factors influencing the extraction process and trends in improving the technique
PublikacjaAnalytical chemists are faced with the daunting challenges of accurately monitoring the state of the environment and the processes taking place in it and of determining an enormous range of analytes often present in trace and ultratrace amounts in sample matrixes with complex or variable compositions. Further challenges are presented by the need to introduce new methodologies into current analytical practice and equipment to comply...
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THE INTERACTION BETWEEN STEEL COLUMN CHORD AND CLOSELY SPACED REINFORCEMENT.
PublikacjaNowadays, more often than before, civil engineering designers are willing to use steel build-up members composed of single or doubled cold-formed chords interconnected using different mechanical connectors. This paper subject is an analysis of cooperation of a closely spaced built-up cold-formed chord interconnected with series of bolts that are located along the length of the member in a specific spacing. This distance along the...
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Problems of modelling toxic compounds emitted by a marine internal combustion engine in unsteady states
PublikacjaContemporary engine tests are performed based on the theory of experiment. The available versions of programmes used for analysing experimental data make frequent use of the multiple regression model, which enables examining effects and interactions between input model parameters and a single output variable. The use of multi-equation models provides more freedom in analysing the measured results, as those models enable simultaneous...