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PL
W artykule przedstawiono wyniki badań symulacyjnych właściwości wybranych cyfrowych algorytmów do estymacji częstotliwości w warunkach pracy przyrządów do dokładnych pomiarów napięcia sinusoidalnego. Zastosowano opracowany algorytm do pomiaru częstotliwości, oparty o pomiar przesunięcia fazowego z zastosowaniem DFT (Dyskretnej Transformaty Fouriera) oraz znane z literatury trzy algorytmy z interpolacją widma i algorytm zupełnych kwadratów błędów TLS (Total Least Squares) . Wyniki badań wskazują, że opracowany algorytm cechuje się najlepszymi właściwościami.
EN
The article presents the results of the simulation properties of selected digital algorithms to estimate the frequency, in the operating conditions of instruments for accurate measurements of sinusoidal voltage. A developed algorithm based on a phase shift measurement with a use of DFT (Discrete Fourier Transform) and four algorithms known from literature, three with spectral interpolation and a total least squares (TLS), were applied. The research results indicate that the developed algorithm is characterized by the best properties.
PL
W artykule przedstawiono nowe czasowo-dyskretne algorytmy czteropunktowe umożliwiające śledzenie częstotliwości sygnału sinusoidalnego. Opracowane algorytmy porównano z czasowo-dyskretnym algorytmem trzypunktowym zaproponowanym przez Vizireanu. W celu porównania algorytmów wykonano symulacje polegające na śledzeniu częstotliwości sygnału sinusoidalnego zakłóconego szumem Gaussa. Pokazano, że opracowane algorytmy umożliwiają śledzenie częstotliwości z większą dokładnością.
EN
The article presents new discrete-time four-point algorithms that enable tracking the sinusoidal signal frequency. The developed algorithms have been compared with the discrete-time three-point algorithm proposed by Vizireanu. In order to compare the algorithms, simulations have been performed, consisting in tracking the sinusoidal signal frequency disturbed by Gaussian noise. It has been shown that the developed algorithms allow frequency tracking with greater accuracy.
PL
Rozwój technologii elektrochemicznych ogniw litowo-jonowych jest jednym z kluczowych problemów, wymagających intensywnych badań. Baterie litowo-jonowe przewyższają inne typy układów elektrochemicznych pod względem pojemności właściwej, dostępnej mocy, odporności na kolejne cykle ładowania-rozładowania i z tego względu są idealnymi systemami do zastosowania w urządzeniach mobilnych oraz pojazdach elektrycznych. Niestety, przy obecnej technologii wytwarzania komercyjnych baterii litowo-jonowych ciągle są to urządzenia drogie i przy nieprawidłowym użytkowaniu mogące spowodować zagrożenie dla zdrowia. W artykule przedstawiono spektrum chemicznych metod modyfikacji materiałów elektrodowych oraz ich wpływ na prace ogniw litowo-jonowych.
EN
The development of new technologies for lithium-ion cells is one of a key problems that require intensive research. Lithium-ion batteries outperform other types of electrochemical systems in terms of specific capacity, available power, cycle life and therefore they are ideal systems for mobile devices and electric vehicles. Unfortunately, with the current technology of producing commercial batteries lithium-ion cells are still expensive and may cause health risks when improperly used. The article presents the spectrum of chemical methods for the modification of electrode materials and their impact on the lithium-ion battery performance.
EN
In this paper, two new sinusoidal signal frequency estimators calculated on the basis of four equally spaced signal samples are presented. These estimators are called four-point estimators. Simulation and experimental research consisting in signal frequency estimation using the invented estimators have been carried out. Simulation has also been performed for frequency tracking. The simulation research was carried out applying the MathCAD computer program that determined samples of a sinusoidal signal disturbed by Gaussian noise. In the experimental research, sinusoidal signal samples were obtained by means of a National Instruments PCI-6024E data acquisition card and an Agilent 33220A function generator. On the basis of the collected samples, the values of four-point estimators invented by the authors and, for comparison, the values of three- and four-point estimators proposed by Vizireanu were determined. Next, estimation errors of the signal frequency were determined. It has been shown that the invented estimators can estimate a signal frequency with greater accuracy.
EN
The sedimentary succession of the largest example of an Upper Oxfordian reef located in the southern part of the Polish sector of the northern Tethys shelf is described. Detailed sampling of exposures enabled characterization of the full succession of facies and microfacies diversity, documenting the reef evolution. The succession studied represents the maximum development of Upper Jurassic reefs in Poland corresponding to the upper Transversarium and the Bifurcatus zones, and followed by drowning of the carbonate platform in the lower Bimmamatum Zone. The reef succession comprises three types of facies, in which eight important microfacies types were distingushed, reflecting several stages of reef development. Mid-ramp, microbial-sponge frame-reefs represent a transgressive depositional sequence, up to tens of metres thick. A microbial-Crescentiella-ooid and ooid-intraclast-bioclast facies form numerous, decimetre- to metre-scale, sequences corresponding to higher-order, transgressive/regressive sea level changes. These facies represent a mid-inner ramp setting when sedimentation was dominated by bioclasts and non-skeletal grains (mainly ooids, oncoids, aggregate grains and intraclasts). The grains were stabilized by microbialites and cemented in early diagenesis, which created grain-dominated, microbial-cement supported reefs. As a result, both the mid-ramp, microbial-sponge frame-reefs and the shallow-water, grain-dominated, microbial-cement supported reefs form extensive, strongly lithified Oxfordian reef complexes in the Kraków-Częstochowa Upland.
PL
Jednym z najistotniejszych składników kosztów wodociagów warszawskich są koszty energii elektrycznej niezbędnej do pompowania. W spółce zainstalowanych jest ponad półtora tysiąca pomp o mocy od ułamka kW aż do 900 kW. Aby zmniejszyć zużycie energii podjęto decyzję o opracowaniu "Programu poprawy efektywności energetycznej". W tym celu MPWiK przeprowadził i nadal przeprowadza modernizację wybranych obiektów.
7
Content available remote Stability of an innovative cold-formed GEB section
EN
This paper is focused on the numerical analysis and experimental test of stability of the cold-formed profile with an innovative GEB cross-section. For the shell model of the axially compressed member, the linear buckling analysis and the nonlinear static analysis were carried out. In the numerical research, the buckling load and the limit load for variable section heights were obtained. Some of the results were compared with the GEB member bearing capacity calculated on the basis of PN-EN 1993-1-1 Eurocode 3 requirements.
8
Content available remote Ocena niepewności estymacji funkcji autokorelacji metodą Monte Carlo
PL
Artykuł dotyczy problematyki wyznaczania niepewności estymacji funkcji autokorelacji sygnału sinusoidalnego w warunkach konwersji a-c z sygnałem ditherowym. W pracy przedstawiono porównanie wyników badań różnych metod, analitycznej oraz symulacyjnej Monte Carlo. Przeprowadzone badania wskazują na przydatność stosowania metody Monte Carlo do oceny niepewności funkcji autokorelacji. Dodatkowo wykazano, że sygnał ditherowy najlepiej stosować zarówno dla małej wartości liczby próbek sygnału, jak i małej liczby bitów przetwornika a-c.
EN
The article discuss the problem of determining the uncertainty of autocorrelation function estimation for sinusoidal signal a-d converted with dither. The paper presents a comparison of test results for two techniques: the analytical method and Monte Carlo simulation. The results show that Monte Carlo method can be successfully applied to determine the autocorrelation function uncertainty. In addition, there were shown that use dither signal provides better results when applied to signals with small number of samples and a-d converter resolution limited do small number of bits.
PL
Obecnie kierowcy dużych miast borykają się z wieloma problemami, takimi jak brak miejsca do parkowania, korki czy wzrost liczby opłat za paliwo. W zatłoczonych miastach istnieje zapotrzebowanie na znalezienie odpowiednich systemów i technologii ułatwiających poruszanie się. Artykuł przedstawia badanie efektywności wdrożenia rozwiązania, jakim jest inteligentna (akomodacyjna) sygnalizacja świetlna, która właściwie reaguje na czas nadawania określonych sygnałów świetlnych w zależności od warunków panujących na skrzyżowaniu. Sprawdzono, czy zastosowanie inteligentnych świateł drogowych przyczynia się do wzrostu efektywności na danym skrzyżowaniu (miarą efektywności jest przepustowość skrzyżowania). Wszystkie obliczenia zostały wykonane w programie GaSygnalizacja oraz GaPrzepustowość, które wykorzystują środowisko Autocad Civil 3D.
EN
Currently, drivers of large cities face a number of problems, such as lack of parking, traffic jams and an increasing number of charges for fuel. In crowded cities, there is a need to find appropriate systems and technologies that facilitate movement. The paper presents the study of the effectiveness of the implementation of the solution, which is smart (accommodative) traffic lights that actually respond to the time of transmission specified light signals depending on specific conditions at the intersection. Examined whether the use of intelligent traffic lights contributes to increased efficiency at the crossroads (a measure of efficiency is the bandwidth intersection). All calculations were made in the program GaSygnalizacja and GaPrzepustowość that use AutoCAD Civil 3D environment.
EN
The paper presents a method of correcting a frequency synchronization error in the sinusoidal voltage measurement. Correction is performed by changing a frequency of the measured signal on the basis of the respectively determined synchronization error by using DFT. Carried out simulation experiments indicate that the correction can theoretically improve the accuracy of measurement of the RMS voltage to the level below 1 ppm. The results of measurements taken by a highly accurate voltmeter Agilent 3458 confirm the conclusions of the simulation, that it is possible to repeatedly reduce the frequency synchronization error by applying the developed correction method in the voltage measurement.
EN
Biodiesel is widely perceived as a source of ecological energy used to power compression ignition engines as an alternative to fossil fuels. Depletion of fossil fuels and increasing environmental awareness of society has led to an increased demand for energy derived from renewable sources. This phenomenon requires acquisition of raw material used for biofuel production. In order avoid controversies related to misuse of edibles; sources of biofuel production should be viewed as inedible or waste materials. This paper presents an analysis of possible sources of animal material intended for biofuel production. An examination of the quality assessment for biofuels obtained in the laboratory setup, produced from swine lard and turkey fat is presented. The results have been compared to rapeseed biofuel and commercial diesel fuel as fuels commonly used to power compression ignition engines. The paper concerns an examination of pure biofuels and their mixtures with commercial diesel fuel in three different proportions. Parameters such as density, viscosity, acid value, cold filter plugging point, oxidation stability, sulphur content, total contamination, water content and flash point has been examined according to procedures outlined in the PN-EN 14214 Standard. Based on the results, biofuels and their mixtures have been analysed for use in compression ignition engines.
12
Content available remote Stability of an imperfect truss loaded by wind
EN
The present paper is devoted to the numerical research of stability of a truss loaded by wind and stiffened by elastic supports located at the top chord. The lateral braces or lateral and torsional braces were taken into account. In this paper, the linear buckling analysis results for the beam and shell model were presented. Two different shapes of initial geometric imperfections were considered in the non-linear static analysis performed for the shell model of the structure. As a result, the truss buckling and the limit load were found to be related to the truss bracing stiffness and the threshold bracing condition, necessary to provide maximum buckling resistance of the truss, was obtained.
PL
Przedstawiono wyniki badań nad opracowaniem koncentratów kosmetyków myjących. Jako potencjalne formy tego typu preparatów zaproponowano liotropowy ciekły kryształ, koacerwat i emulsję. Wykazano zalety i wady wytwarzania i stosowania tego typu produktów w odniesieniu do właściwości reologicznych, rozpuszczalności w wodzie i stabilności produktu. Stwierdzono, że spośród badanych form preparatów, jedynie koacerwat może predysponować do miana koncentratu. W przypadku produktów w formie emulsji i liotropowego ciekłego kryształu istniała możliwość uzyskania preparatu o względnie wysokim stężeniu substancji aktywnych, ale po rozcieńczeniu nie otrzymywano kosmetyków o wymaganych przez konsumentów właściwościach użytkowych.
EN
Lyotropic liq. Crystal, coacervate and emulsion concs. were prepd. by compounding com. surfactants (Na lauryl ether sulfate, ethylene oxide-lauryl alc. adduct, isopropyl palmitate, stawbery seed oil), preservatives and H₂O and studied for rheol. properties, soly. in water and stability. Only the coacervate meet all user requirements. The concn. relationship of the coacervate viscosity showed a pecurial max. as diln. of the coacerwate with water resulted in increasing its viscosity.
EN
Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic fi eld. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (Ta). At higher Ta, hematite was the dominant phase in the nanowires.
EN
The paper is devoted to the numerical and experimental research of stability of a truss with side elastic supports at the top chord. The structure is a model of a real roof truss scaled by factor ¼. The linear buckling analysis and non-linear static analysis were carried out. The buckling length factor for the compressed top chord was calculated and the limit load for the imperfect truss shell model with respect to brace stiffness was obtained. The relation between brace normal force and loading of the truss is presented. The threshold stiffness of braces necessary to obtain the maximum buckling load was found. The truss load bearing capacity obtained from numerical analysis was compared with Eurocode 3 requirements.
EN
The present paper is devoted to the numerical analysis and experimental tests of compressed bars with built–up cross section which are commonly used as a top chord of the roof trusses. The significant impact on carrying capacity for that kind of elements in case of out-of-plane buckling is appropriate choice of battens which are used to provide interaction between separate members. Linear buckling analysis results and nonlinear static analysis results, with material and geometrical nonlinearity, are presented for the bar with built-up cross section which was used as the top chord of the truss made in reality. Diagonals and verticals which are supports for the top chord between marginal joints were replaced by the elastic supports. The threshold stiffness (minimum stiffness) for the intermediate elastic supports which ensures maximum buckling load was appointed for the beam and shell model of the structure. The magnitude of limit load depended on length of the battens was calculated for models with initial geometric imperfections. The experimental tests results for the axially compressed bars with built-up cross section and elastic support are presented.
PL
Niniejsza praca poświecona jest analizom numerycznym i badaniom doświadczalnym ściskanych prętów złożonych, które są często stosowane, jako pasy górne kratownic dachowych. Istotny wpływ na nośność tego typu elementów, przy założeniu wyboczenia z płaszczyzny układu, ma odpowiedni dobór przewiązek zapewniający współpracę poszczególnych gałęzi. W pracy przedstawiono rezultaty liniowych analiz stateczności oraz fizycznie i geometrycznie nieliniowych analiz statycznych dla pręta złożonego, z którego zbudowany jest pas górny kratownicy wykonanej w rzeczywistości. Słupki i krzyżulce podpierające pas między węzłami skrajnymi zastąpiono podporami sprężystymi. Wyznaczono graniczną (minimalna) sztywność sprężystych podpór pośrednich zapewniającą maksymalną wartość obciążenia krytycznego dla modelu prętowego i powłokowego konstrukcji. Podano wartości obciążenia granicznego zależnego od długości zastosowanych przewiązek dla modeli konstrukcji ze wstępnymi imperfekcjami geometrycznymi. Zaprezentowane zostały rezultaty badań doświadczalnych osiowo ściskanych prętów złożonych z podporą sprężystą.
EN
A spectacular epigenetic silicification was encountered in the Oxfordian bedded limestones exposed in the Sokole Hills situated in the Kraków-Częstochowa Upland. The main epigenetic mineral is microcrystalline quartz accompanied by minor goethite, hematite, barite, galena and sphalerite. Locally, the mineralized limestones reveal Pb and Cu contents exceeding over 150 times the background values of these metals in unmineralized limestones. The epigenetic mineralization of the bedded limestones was probably a two-stage process. During the first, Early Cretaceous stage, silicified limestones formed at the erosional surface of a denuded carbonate complex. Such silicification greatly limited the progress of the first karstification phase of the Upper Jurassic carbonates initiated in the Hauterivian. The sources of silica accumulated in the limestones were descending solutions enriched in silica derived from the weathering zone. This silicification affected the topmost part of the Upper Jurassic massive limestones and the deeper portions of the bedded limestones along the fracture systems and stylolites. Early Cretaceous tectonic activity generated new dislocations and re-opened the existing faults, which were subsequently filled with permeable Albian quartz sands. These openings became the migration pathways for ascending, warm, relict, sulphide-carrying hydrothermal solutions at the second formation stage of the epigenetic mineralization. The newly supplied silica from the Albian sands precipitated on the silicified limestones and, as concentric rims, on brecciated, early diagenetic cherts. The second-stage mineralization proceeded under phreatic conditions, presumably close to a fluctuating mixing zone of ascending, warm hydrothermal solutions and descending cold groundwaters. The brecciated cherts acting as silica crystallization nuclei indicate that the last mineralization stage probably followed the final phase of Cenozoic faulting.
PL
W pracy przedstawiono wyniki badań właściwości metrologicznych algorytmu DFT i klasycznego do wyznaczania wartości skutecznej napięcia sinusoidalnego w pomiarach z zastosowaniem integracyjnego woltomierza próbkującego. Algorytmy badano dla wybranych, najważniejszych źródeł niepewności z zastosowaniem metody Monte Carlo. Na podstawie wyników badań stwierdzono, że właściwości obu algorytmów różnią się tylko w pomiarach mało dokładnych. Na poziomie niepewności pomiaru napięcia poniżej kilkudziesięciu ppm algorytmy zwracają jednakowe wyniki.
EN
The paper presents research results of metrological properties of algorithm DFT (4) and classical (5) for determining the RMS sinusoidal voltage measurements using an integrating sampling voltmeter. Tests were performed comparing measurement uncertainty calculated using a Monte Carlo method for both algorithms. Analyses were performed for selected, the most important sources of RMS voltage measurement uncertainty. Based on the results, it was found that the properties of both algorithms differ only in less accurate measurements. Below tens of ppm level voltage measurement uncertainty algorithms return the same results.
PL
W artykule przedstawiono wyniki badania własności wybranej charakterystyki sygnału sinusoidalnego wyznaczanej na podstawie możliwie najmniejszej liczby próbek sygnału. Do badań zastosowano funkcję autokorelacji sygnału. Pokazano, że do wyznaczania wartości funkcji autokorelacji wystarczy sześć próbek sygnału oraz, że podczas obliczania wartości funkcji autokorelacji odpowiedni dobór parametrów sygnału powoduje wyeliminowanie skutków operacji kwantowania.
EN
This paper presents the results of a research of the selected sinusoidal signal characteristic obtained from the smallest possible number of the signal samples. Research was carried out using the autocorrelation function. It was shown that the values of the autocorrelation function can be determined on the basis of six signal samples. It was also shown that the appropriate selection of the signal parameters eliminates the effects of quantization. Chapter 1 provides basic information on the reasons for study of the autocorrelation function properties. In Chapter 2 the results of the theoretical study were presented. Th. 1 deals with the determination of the sinusoidal signal autocorrelation function and her estimator, when M >> 1, where M is the number of samples. Eq. (1) describes the relation between the number of samples and the delay times of the autocorrelation function. Eq. (3) presents the autocorrelation function estimator. In the second Theorem, it has been shown that, to determine the autocorrelation function values can be used only six sinusoidal signal samples. In the next part of Chapter 2 the third Theorem has been presented. It has been shown that if the initial phase of the signal is equal to (...)/2, then the effects of quantization are eliminated. In Chapter 3 the results of the experimental research were presented. Eq. (22) and (23) describes the mean of the mean square estimator obtained on the basis the autocorrelation function. In Fig. 1 the eq. (22) and (23) have been shown.
EN
The paper presents a comparative analysis of a Lower Kimmeridgian layer with bored and encrusted hiatus concretions collected in three study areas, located in Central Poland. These studies demonstrate distinct similarities between the hiatus concretions in terms of their origin, development and stratigraphic position. The layer with its characteristic concretions seems to represent an important marker horizon for the Lower Kimmeridgian successions in Central Poland. The identification of this marker horizon in drill cores and exposures could be important for definition of the stratigraphic position of the sediments, which otherwise lack appropriate biostratigraphic information. The matrix of the concretions is composed of pelagic calciturbidites, which reflect flooding of the early Kimmeridgian platform. These sediments were lithified early and formed a hardground. The origin of the hiatus concretions probably is related to erosion of the hardground, followed by redeposition and several phases of exhumation and erosion, preceding final burial. The characteristic ecological successions, observed in the concretions, document an evolution from soft to firm and hard marine substrates, typical of hardgrounds and evidenced by various burrows, borings (Gastrochaenolites, Trypanites), and epizoans. Calciturbidite sedimentation, hardground erosion and redeposition of the hiatus concretions, known from deposits of the Platynota Zone in Central Poland, were associated with synsedimentary activity of the Holy Cross Fault, on the NE margin of the extensive, tectonic Małopolska Block.
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