Filtry
wszystkich: 3378
wybranych: 2628
-
Katalog
- Publikacje 2628 wyników po odfiltrowaniu
- Czasopisma 43 wyników po odfiltrowaniu
- Wydawnictwa 1 wyników po odfiltrowaniu
- Osoby 50 wyników po odfiltrowaniu
- Wynalazki 2 wyników po odfiltrowaniu
- Projekty 5 wyników po odfiltrowaniu
- Laboratoria 1 wyników po odfiltrowaniu
- Aparatura Badawcza 3 wyników po odfiltrowaniu
- Kursy Online 53 wyników po odfiltrowaniu
- Wydarzenia 1 wyników po odfiltrowaniu
- Dane Badawcze 591 wyników po odfiltrowaniu
Filtry wybranego katalogu
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: THE LASER IMPULSE
-
A tool for designing water tanks for measuring hydroacoustic transducers
PublikacjaSpecial water tanks are commonly used to measure the parameters of underwater acoustic systems. They must meet specific requirements, the fulfilment of which ensures very small but acceptable measurement errors. These requirements define the size of the tank and its shape as well as the strong attenuation of reflected waves. At the design stage, it is necessary to determine the impact of the tank structure on the measurement errors...
-
Transformation of Small and Medium - Sized Enterprises in Pomerania due to staging the EURO 2012 with particular emphasis on the hotel industry
PublikacjaKluczowym motywem rozważań w opracowaniu jest kwestia transformacji biznesu. Przedmiotem analizy jest przekształcanie impulsów i procesów przebiegających w sferze publicznej na działalność przedsiębiorstw sektora MŚP. Bezpośrednim impulsem ilustrującym reaktywność małych przedsiębiorstw była decyzja o mistrzostwach Europy w piłce nożnej w Polsce w 2012 roku. Przedsiębiorczość wyraziła się znacznym rozwojem bazy hotelowej w wielu...
-
Światłowodowe sensory odkształceń i temperatury wykorzystujące pomiar czasu .
PublikacjaW pracy przedstawiono zasadę działania światłowodowych sensorów wykorzystujących pomiar czasu przelotu krótkich impulsów laserowych. Sensory te mogą pracować w trybie transmisyjnym lub odbiciowym. Dzięki swej małej tłumienności można je łatwo łączyć w sieci o różnych topologiach, mających wiele (dziesiątki lub setki punktów pomiarowych). Przykładem sensora z pomiarem czasu przelotu jest odcinek światłowodu jednomodowego poddany...
-
Diagnostyka analogowych filtrów wielosekcyjnych oparta na magistrali testującej IEEE1149.1
PublikacjaPrzedstawiono nową koncepcję testera JTAG BIST do samo-testowania torów analogowych opartych na wielosekcyjnych filtrach wyższego rzędu w mieszanych sygnałowo mikrosystemach elektronicznych sterowanych mikrokontrolerami i wyposażonych w magistralę testującą IEEE1149.1 (JTAG). Bazuje ona na metodzie diagnostycznej opartej na przekształce-niu transformującym próbki odpowiedzi czasowych kolejnych sekcji filtra pobudzonego impulsem...
-
Rotordynamic characteristics of a chamber seal
PublikacjaThe paper presents the results of numerical and experimental investigations into pressure forces generated in a turbine labyrinth seal of a modernized type. The experiments were performed on a single-stage air model turbine of the impulse type. The experiments were performed on a single-stage air model turbine of the impulse type. The experimental data were compared with theoretical results obtained by means of CFD Fluent Code....
-
User Orientation Detection in Relation to Antenna Geometry in Ultra-Wideband Wireless Body Area Networks Using Deep Learning
PublikacjaIn this paper, the issue of detecting a user’s position in relation to the antenna geometry in ultra-wideband (UWB) off-body wireless body area network (WBAN) communication using deep learning methods is presented. To measure the impulse response of the channel, a measurement stand consisting of EVB1000 devices and DW1000 radio modules was developed and indoor static measurement scenarios were performed. It was proven that for...
-
Adhesive compliance effect in mode I separation:Profilometry approach
PublikacjaThe effect of adhesive compliance on the deflection of a loaded, bonded beam was studied using laser profilometry. Experimental data obtained were compared with both Euler-Bernoulli (encastré) and Winkler (one parameter elastic foundation) models. A third, analytical, 2D model, based on shear within the adhesive layer (two parameter elastic foundation), was introduced. Finite element analysis (FEA) was also used to study the effect...
-
Properties of Barium Cerate-Zirconate Thin Films
PublikacjaIn this work, we review several experimental results showing the electrical properties of barium cerate-zirconate thin films and discuss them in view of the possible influence of various factors on their properties. Most of the presented Ba(Ce, Zr, Y)O3 thin films were formed by the pulsed laser deposition (PLD) technique, however thin films prepared using other methods, like RF magnetron sputtering, electron-beam deposition, powder...
-
A BRIEF REVIEW AND COMPARISON OF SELECTED EXPERIMENTAL METHODS FOR MEASURING NATURAL FREQUENCIES OF CIRCULAR SAW BLADES
PublikacjaDifferent methods for the empirical determination of the natural frequencies of circular saw blades are presented. Stationary methods, such as the harmonic and impulse tests, are discussed and the results of related comparison are given. The comparison of the methods revealed their degree of practical usefulness and their accuracy in determining natural frequencies. A combination of specific methods is proposed, which should allow...
-
The vortex flow caused by sound in a bubbly liquid
PublikacjaGeneration of vorticity in the field of intense sound in a bubbly liquid in the free half-space is considered. The reasons for generation of vorticity are nonlinearity, diffraction, and dispersion. Acoustic streaming differs from that in a Newtonian fluid. Under some conditions, the vortex flow changes its direction. Conclusions concern streaming induced by a harmonic or an impulse Gaussian beam.
-
Analog fault signature based on sigma-delta modulation and oscillation-test methodology.
PublikacjaW artykule dokonano przeglądu prac z zakresu testowania układów elektronicznych metodą oscylacyjną. Wskazując na niedostatki aktualnie stosowanej techniki testowania oscylacyjnego zaproponowano nową sygnaturę uszkodzeń dla układów analogowych. Proponowany parametr diagnostyczny jest wydobywany z odpowiedzi czasowej oscylatora testującego, w układzie złożonym z detektora szczytowego, modulatora sigma-delta oraz licznika rewersyjnego....
-
Selected problems of high-power sonar sources
PublikacjaSpecyfika pracy współczesnych sonarów aktywnych wymaga cyklicznego wypełnienia energią szerokiego sektora sondowania. W przypadku użycia płaskich anten nadawczych oznacza to zwykle konieczność skupienia energii akustycznego impulsu nadawczego na stosunkowo małej powierzchni czynnej przetwornika elektroakustycznego (kluczowe znaczenie odgrywa tu częstotliwość pracy systemu). Zjawiska towarzyszące dużym poziomom źródła mogą powodować...
-
Fire Protection and Materials Flammability Control by Artificial Intelligence
PublikacjaFire safety has become a major challenge of materials developers because of the massive production of organic materials, often combustibles, and their use for different purposes. In this sense, fire safety is critically considered in the development of engineering materials [1, 2]. The multiplicity of parameters contributing to the development of formulation of flame-retardant materials from one side and the sustainability concerns...
-
Self-adjusting sub-sample delay estimator based on fractional delaying Hilbert transform filter
PublikacjaZaprezentowano nowe rozwiązanie samo-nastrajalnego estymatora opóźnienia sygnału sinusoidalnego, działającego w czasie dyskretnym. Zastosowano filtr Hilberta o skończonej odpowiedzi ipulsowej (FIR od ang. finite impulse response) zagregowany z filtrem ułamkowo-opóźniającym. Zilustrowano performancję estymatora, również w obecności szumu. Przeanalizowano jego złożoność numeryczną.
-
Regularized Identification of Time-Varying FIR Systems Based on Generalized Cross-Validation
PublikacjaA new regularization method is proposed and applied to identification of time-varying finite impulse response systems. We show, that by a careful design of the regularization constraint, one can improve estimation results, especially in the presence of strong measurement noise. We also show that the the most appropriate regularization gain can be found by direct optimization of the generalized cross-validation criterion.
-
FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublikacjaThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
-
Pressure Pulsations in Turbine Blade Seal
PublikacjaThe paper presents the results of experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type. The performed experimental research proved that in a shroud clearance the pressure pulsates and the effects of the nozzle trailing edge thickness as well as the influence of the rotor blades are observed. The exemplary results...
-
Container Cargo Safety. New solutions and future trends
PublikacjaThe smoothness and flexibility of distribution of goods by containers are teh most important impulses for the development in these means of transport. But the second main reason for the growing containerization of freifht is cargo safety.
-
The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublikacjaLatest development in the field of welding technology and prefabrication enabled massive production of thin-walled sandwich structures. Multi-layered sandwich structures are fabricated with the use of high-power CO2 lasers, friction welding, arc welding, hybrid welding, or other technique designed for the special purpose. Steel or aluminium alloy plates with thickness between 1 and 5 mm are connected by internal stiffeners. Strength...
-
Widening of the electroactivity potential range by composite formation – capacitive properties of TiO2/BiVO4/PEDOT:PSS electrodes in contact with an aqueous electrolyte
PublikacjaComposites based on the titania nanotubes were tested in aqueous electrolyte as a potential electrode material for energy storage devices. The nanotubular morphology of TiO2 was obtained by Ti anodization. TiO2 nanotubes were covered by a thin layer of bismuth vanadate using pulsed laser deposition. The formation of the TiO2/BiVO4 junction leads to enhancement of pseudocapacitance in the cathodic potential range. The third component,...
-
Latent fingerprint imaging by spectroscopic optical coherence tomography
PublikacjaOptical coherence tomography (OCT) is a non-contact and non-invasive optical method for evaluating semitransparent and scattering objects. Its unique features, such as non-destructive 3D measurements of tested objects with a fast scanning rate, make this technique interesting for latent fingerprint reading, which is the subject of this paper. So far, OCT has not found widespread use for reading fingerprints directly from surfaces...
-
Formation of acoustic field in rooms
PublikacjaPaper describes known form literature method of sound diffusity index assesment, which utilizes impulse response of the room. Process of froming diffused sound field using this method was investigated.Increase of sound diffusity index in time was noted in rooms differing in shape,volume and reverberation time. Exponential growth of sound diffusion index was noted which correlates with other acoustical rooms measures.
-
Online Sound Restoration for Digital Library Applications
PublikacjaA system for sound restoration was conceived and engineered having the following features: no special sound restoration software is needed to perform audio restoration by the user, the process of restoration employs automatic reduction of noise, wow and impulse distortions performed in the online mode, no skills in digital signal processing from the user are needed. The principles of the created system and its features as well...
-
A New Method of Noncausal Identification of Time-varying Systems
PublikacjaThe paper shows that the problem of noncausal identification of a time-varying FIR (finite impulse response) sys- tem can be reformulated, and solved, as a problem of smoothing of the preestimated parameter trajectories. Characteristics of the smoothing filter should be chosen so as to provide the best trade- off between the bias and variance of the resulting estimates. It is shown that optimization of the smoothing operation can...
-
Teledetekcyjne badanie konstrukcyjnych elementów żelbetowych z użyciem naziemnego skaningu laserowego
PublikacjaWspółczesna technologia naziemnego skaningu laserowego (TLS) z użyciem skanerów geodezyjnych o zasięgu większym niż 50 metrów pozwala na pomiar geometrii elementów konstrukcyjnych z dokładnością bliską 1 mm. Autorzy, w oparciu o badania laboratoryjne i doświadczenia własne, prezentują rozwiązanie pozwalające na wstępną ocenę belek żelbetowych jako podstawowych elementów konstrukcyjnych budowli typu mosty, wiadukty, budynki wielkopowierzchniowe. Przedmiotem...
-
Jeffreys heat conduction in coupled semispaces subjected to interfacial heating
PublikacjaA Jeffreys heat conduction problem for coupled semispaces subjected to the action of an interfacial heat source was defined. An analytical solution of the problem was derived for a polynomial specific power of the heat source using the Laplace transform approach. The asymptotic and parametric analysis was performed for different ratios of thermal conductivities , thermal diffusivities , thermal relaxation times and coefficients...
-
Acoustic Streaming Induced by Periodic and Aperiodic Sound in a Bubbly Liquid
PublikacjaThe vortex ow which follows intense sound propagating in a bubbly liquid, is considered. The reasons for acoustic streaming are both nonlinearity and dispersion. That makes streaming especial as compared with that in a Newtonian uid. Conclusions concern the vortex ow induced in a half-space by initially harmonic or impulse Gaussian beam. The vortex ow recalls a turbulent ow with increasing in time number of small-scale vortices...
-
Inwentaryzacja miejsc zdarzeń kryminalnych przy wykorzystaniu naziemnego skaningu laserowego
PublikacjaInwentaryzacja miejsc zdarzeń kryminalnych przy wykorzystaniu naziemnego skaningu laserowego jest rozwiązaniem często spotykanym przy w rozwiniętych krajach Europy i Ameryki Północnej. W Polsce znajdujemy pierwsze zastosowania do rejestrowania zdarzeń kryminalnych o szczególnym stopni skomplikowania lub związanych z nieprzeciętną liczbą ofiar. Zasadniczo jednak skaning laserowy stosuje się w sprawach o zabójstwo, a rzadko w rozwiązaniach...
-
Assessment of Wide-Sense Stationarity of an Underwater Acoustic Channel Based on a Pseudo-Random Binary Sequence Probe Signal
PublikacjaThe performances of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Designing the physical layer of a reliable data transmission system requires a knowledge of channel characteristics in terms of the specific parameters of the stochastic model. The Wide-Sense Stationary Uncorrelated Scattering (WSSUS) assumption simplifies the stochastic description...
-
The application of non-destructive methods in the diagnostics of the approach pavement at the bridges
PublikacjaThe article presents the possibility of using non-destructive methods of road pavement diagnostics as an alternative to traditional means to assess the reasons for premature cracks adjacent to bridge objects. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, an effective tool...
-
Między XIX a XXI wiekiem. Obecny stan filozofii i jego nieco zapomniane źródła
PublikacjaW XiX wieku rozpoczął się kryzys filozofii. Przestała ona odgrywać wiodącą rolę na uniwersytecie i impulsy płynące z jej strony nie odgrywały już większej roli. Wskutek ogromnego rozwoju nauk przyrodniczych praktyka naukowa staje się afilozoficzna i do samej filozofii zaczęła odnosić się wrogo. Filozofia swój zasadniczy przedmiot zainteresowań – byt, obszar tradycyjnej metafizyki, musiała oddać szybko rozwijającym się naukom szczegółowym...
-
The Influence of Modelling Material Zones on Strains and Stresses at Weld Toe Notch
PublikacjaThe latest development in the field of welding technology enabled prefabrication of thin-walled sandwich structures in an industrial scale. Sandwich structures fabricated of steel, or aluminium alloy plates and stiffeners are welded with the use of hi-power CO2 lasers. Strength analysis of such structures with the use of finite element method needs proper material modelling.In this paper the material model of steel sandwich panel...
-
Damage imaging algorithm for non-destructive inspection of CFRP/steel adhesive joints based on ultrasonic guided wave propagation
PublikacjaThe paper concerns assessing the quality of the adhesive connection between a steel plate and the reinforcing CFRP laminate. A three-stage algorithm for non-destructive damage imaging was developed. As the first step, an initial study involving dispersion curves of joint components was executed to determine the material parameters and the appropriate excitation frequency. During the second step, damage identification in three-layer...
-
Hysteresis curves for some periodic and aperiodic perturbations in gases
PublikacjaEvolution of sound in a medium whose properties irreversibly vary in the course of wave propagation, is studied. For example, a gas that is a particular case of a Newtonian fluid is considered. Hysteresis curves, pictorial representations of irreversible attenuation of the sound energy, in the plane of thermodynamic states are plotted. The irreversible losses in internal energy are proportional to the total attenuation and depend...
-
Parametry uziemień przy przebiegach udarowych i wysokoczęstotliwościowych
PublikacjaW artykule skupiono się na porównaniu dwóch metod badania impedancji uziemienia odgromowego: udarowej z wysoką częstotliwościową. Zestawiono wyniki pomiarów istniejących uziemień z wynikami komputerowych obliczeń symulacyjnych przeprowadzonych w środowisku programu PSIM. Uzyskane wyniki wskazują na poprawność przyjętego toku modelowania, a uzyskane w ten sposób dane mogą być przydatne w fazie projektowania do szacowania...
-
Pressure pulsations in turbine blade seal clearance
PublikacjaThe paper presents the results of numerical and experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type, while the numerical results were obtained by means of CFD Fluent Code. The performed experimental research and numerical calculations prove that in a shroud clearance the pressure pulsates and the effects of...
-
Square root RC Nyquist filter of fractional delay
PublikacjaIn this paper we propose a discrete-time FIR (finite impulse response) filter which couples the role of square root Nyquist filter with fractional delay filter. This filter enables to substitute for a cascade of square root RC (SRRC) Nyquist filter and fractional delay filter in one device/algorithm. The aim is to compensate for transmission delay in communication system. Statistically defined performances, e.g. BER (bit error...
-
Generalized Savitzky–Golay filters for identification of nonstationary systems
PublikacjaThe problem of identification of nonstationary systems using noncausal estimation schemes is consid-ered and a new class of identification algorithms, combining the basis functions approach with localestimationtechnique,isdescribed.Unliketheclassicalbasisfunctionestimationschemes,theproposedlocal basis function estimators are not used to obtain interval approximations of the parametertrajectory, but provide a sequence of point...
-
Estymacja położenia węzłów ruchomych w sieci UWB synchronizowanej emisją z węzła nieruchomego
PublikacjaW referacie przedstawiono wyniki testów możliwości wykorzystania modemów IR UWB (Impulse Radio Ultra-Wide Band) typu DWM1000 do budowy sieci radiolokalizacyjnej, w której położenie węzłów ruchomych jest estymowane na podstawie pomiarów różnic odległości metodą TDOA (Time Difference of Arrival). Opisana została struktura sieci i sposób synchronizacji pomiarów czasów w nieruchomych węzłach referencyjnych przez cykliczny odbiór sygnałów...
-
On the preestimation technique and its application to identification of nonstationary systems
PublikacjaThe problem of noncausal identification of a nonstationary stochastic FIR (finite impulse response) sys- tem is reformulated, and solved, as a problem of smoothing of preestimated parameter trajectories. Three approaches to preestimation are critically analyzed and compared. It is shown that optimization of the smoothing operation can be performed adaptively using the parallel estimation technique. The new approach is computationally...
-
Nondestructive methods complemented by FEM calculations in diagnostics of cracks in bridge approach pavement
PublikacjaNondestructive methods of road pavement diagnostics are an alternative to traditional approach to pavement failure investigation. The article presents a detailed multidisciplinary inspection carried out using ground-penetrating radar (GPR), laser scanning technology and finite element method (FEM) calculations. It was done in order to assess the factors that contributed to occurrence of premature cracks of a bridge approach pavement....
-
Wire Arc Additive Manufactured Mild Steel and Austenitic Stainless Steel Components: Microstructure, Mechanical Properties and Residual Stresses
PublikacjaWire arc additive manufacturing (WAAM) is an additive manufacturing process based on the arc welding process in which wire is melted by an electric arc and deposited layer by layer. Due to the cost and rate benefits over powder-based additive manufacturing technologies and other alternative heat sources such as laser and electron beams, the process is currently receiving much attention in the industrial production sector. The gas...
-
Superimposed ice as nutrient storage
PublikacjaNutrient cycling in the glacial environment is known from the perspective of meltwater release and snowpack elution processes, but the superimposed ice temporary storage remains poorly understood. In this study, the enrichment of superimposed ice in nutrient ions: nitrite, nitrate and ammonium was studied in more detail. The release of these ions from superimposed ice into a supraglacial stream was considered also, additionally...
-
Berliński krajobraz pamięci
PublikacjaZjednoczenie Niemiec, w 1989 roku, stało się impulsem do dyskusji na temat form upamiętniania wydarzeń drugiej wojny światowej w Niemczech. Od tego czasu w Berlinie powstało kilka miejsc pamięci tworząc specyficzny krajobraz pamięci.
-
Wpływ azotowania jarzeniowego i laserowego nadtapiania na odporność kawitacyjną stali X5CrNi18-10
PublikacjaNierdzewne stale austenityczne charakteryzują się doskonałą odpornością korozyjną, aczkolwiek niskimi właściwościami mechanicznymi. W wielu przypadkach ogranicza to ich eksploatację w warunkach przemysłowych. Ponadto, nierdzewne stale austenityczne są wrażliwe na korozję lokalną w obecności jonów halogenkowych. Technologie materiałowe, które dają potencjalne możliwości otrzymywania korzystnego wpływu na właściwości mechaniczne...
-
Perfect thermal contact of hyperbolic conduction semispaces with an interfacial heat source
PublikacjaThe problem of thermal contact between two bodies with a heat source at their interface presents great scientific and practical interest. On the time scale of a nanosecond or shorter, heat propagation should be considered in the form of thermal waves of finite speeds. This study investigated the thermal behaviour of hyperbolic conduction semispaces in perfect thermal contact subjected to the action of an interfacial heat source....
-
Towards high quality ITO coatings: the impact of nitrogen admixture in HiPIMS discharges
PublikacjaThe paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56 MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore,...
-
Curves of thermodynamic states in some fluids with dispersion
Publikacjavariations in the thermodynamic state of a dispersive medium, caused by sound, are studied. A bubbly liquid and a Maxwell fluid are considered as examples. Curves in the plane of thermodynamic states are plotted. They are in fact pictorial images of linear relations of excess pressure and excess density in the acoustic wave which reflect irreversible attenuation of the sound energy. The curves account for the nonlinear generation...
-
A New Expression for the 3-D Dyadic FDTD-Compatible Green's Function Based on Multidimensional Z-Transform
PublikacjaIn this letter, a new analytic expression for the time-domain discrete Green's function (DGF) is derived for the 3-D finite-difference time-domain (FDTD) grid. The derivation employs the multidimensional Z-transform and the impulse response of the discretized scalar wave equation (i.e., scalar DGF). The derived DGF expression involves elementary functions only and requires the implementation of a single function in the multiple-precision...
-
Measurement Stand and Methodology for Research of the Off-Body and Body-to-Body Radio Channels in WBANs with Different Diversity Schemes
PublikacjaThe concept of an experimental test bed for system loss and channel impulse response measurements for off-body and body-to-body radio channels in wireless body area networks (WBANs) is fully described. The possible measurement scenarios that may occur in investigation of off-body and body-to-body channels are classified and described in detail. Additionally, an evaluation is provided of the standard and expanded uncertainties of...