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Search results for: MARS
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Analysis of distance measurement errors in CW FM sonar with MLS code modulation
PublicationAlthough used in the classic silent sonar, the CW FM sounding signal has a major flaw which is its inaccuracy in determining the distance to a target. The authors of the article have developed a concept of silent sonar using frequency modulation signals switched by pseudorandom codes, already discussed in their previous work. This article presents a detailed analysis of errors in CW FM sonar with pseudo-random sequence code modulation...
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Continuous wave sonar with hyperbolic frequency modulation keyed by pseudo-random sequence
PublicationA 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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Impact of Spatial Noise Correlation on Bearing Accuracy in DIFAR Systems
PublicationDIFAR type underwater passive systems are one of the more commonly used tools for detecting submarines. At the design stage, which usually uses computer simulations, it is necessary to generate acoustic noise of the sea. It has been shown that correlating noise significantly reduces these errors compared to the assumption that noise is uncorrelated. In addition, bearing errors have been shown to be the same in systems with a commonly...
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Direction-of-Arrival Estimation Methods in Interferometric Echo Sounding
PublicationNowadays, there are two leading sea sounding technologies: the multibeam echo sounder and the multiphase echo sounder (also known as phase-dierence side scan sonar or bathymetric side scan sonar). Both solutions have their advantages and disadvantages, and they can be perceived as complementary to each other. The article reviews the development of interferometric echo sounding array configurations and the various methods applied...
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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Shallow Water Experiment of OFDM Underwater Acoustic Communications
PublicationThe large variability of communication properties of underwater acoustic channels, and especially the strongly varying instantaneous conditions in shallow waters, is a challenge for the designers of underwater acoustic communication (UAC) systems. The use of phase modulated signals does not allow reliable data transmission through such a tough communication channel. However, orthogonal frequency-division multiplexing (OFDM), being...
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Underwater Navigation System Based on Doppler Shifts of a Continuous Wave
PublicationThe paper describes a concept of an underwater navigation system designed to determine the location and speed of its ROVs or divers. Conducted by the Department of Marine Electronic Systems at the Gdansk University of Technology for several years, research has focused on navigation systems which determine positions on the basis of Doppler shifts of echo signals reflected from a moving object. This article presents a different version...
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A tool for designing water tanks for measuring hydroacoustic transducers
PublicationSpecial 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...
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Experimental tests of selected damping and sound-absorbing materials to determine their suitability for sound attenuation of hydroacoustic measuring tank
PublicationThe article contains a description and results of the measurements necessary to select the optimal material for damping two hydroacoustic measuring tanks according to simple suitability criteria, i.e. obtaining minimal sound reflections from the water surface, walls and bottom in these pools by covering the surfaces with sound-dispersing materials or acoustic absorbers. One will be larger (15x10x10 m) for measurements in the range...
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Noise effect on parameters of quiet sonar with code modulation
PublicationEarlier publications of the paper authors have shown that the use of code keying mixed with the CW FM sound signal allows the significant reduction in the distance measurement error, compared to classic silent CW FM sonar. In addition to the code modulation parameters, the magnitude of this error is influenced by the received input acoustic noise. The article shows the dependence of the input signal-to-noise ratio and the sound...
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Suppression of deleterious effects of free silanols in liquid chromatography by imidazolium tetrafluoroborate ionic liquids
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Bacterial community succession in an Arctic lake–stream system (Brattegg Valley, SW Spitsbergen)
PublicationThe factors affecting prokaryotic and virus structure dynamics and bacterial commu-nity composition (BCC) in aquatic habitats along a ca. 1500 m of the Brattegg Valley lake–stream system (SW Spitsbergen) composed of three postglacial lakes created by Brattegg Glacier meltwater were examined. A high number of small-volume prokaryotic cells were found in the recently-formed, deep, upper,...
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Solid-State Dewetting as a Driving Force for Structural Transformation and Magnetization Reversal Mechniasm in FePd Thin Films
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Electrical Transport and Magnetic Properties of Metal/Metal Oxide/Metal Junctions Based on Anodized Metal Oxides
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From monetite plate to hydroxyapatite nanofibers by monoethanolamine assisted hydrothermal approach
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Badanie stanu naprężeń w elementach turbin za pomocą efektu Barkhausena
PublicationPrzedstawiono wyniki badań stanu naprężeń w elementach turbin z wykorzystaniem polowego efektu Barkhausena. Badane były naprężenia własne w łopatkach aktualnie eksploatowanych oraz po modernizacji. Wyniki tych badań wskazują jednoznacznie na korzyści wynikające z zastosowania efektu Barkhausena jako podstawy nieniszczącej metody oceny poziomu naprężeń
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Doświadczenia z wdrażania automatycznego nadzoru nad ruchem drogowym.
PublicationReferat dotyczy doświadczeń w wdrażaniu automatycznego nadzoru nad ruchem drogowym a w szczególności zastosowania automatycznych urządzeń (kamery) monitorujących prędkość oraz wjazd na skrzyzowanie na czerwonym świetle, wpływu zastosowania kamer na redukcję prędkości oraz wypadków. Omówiono zastosowanie podobnych rozwiązań na terenie województwa pomorskiego oraz ocenę efektywności podjętych działań.
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Vitamin D serum levels in multiorgan failure critically ill patients undergoing continuous renal replacement therapies
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Introduction in to tyre simulations
PublicationW artykule przedstawiono wyniki symulacji komputerowej zachowania się opony w czasie badania jej oporów toczenia w oparciu o program LMS Virtual Lab. Przedstawiono także wnioski wynikające z przeprowadzonej symulacji.
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The oil film parameters of the wankel engine apex seal in aspects of durability of mating elements
PublicationThe Wankel engine is one of only few alternatives to the reciprocating engines. The advantages such as good value of maximum engine power to its mass ratio are still present and can have great sense in selected fields of application, for example General Aviation. Nevertheless the disadvantages of the Wankel engine design have never lost its importance and still pose an obstacle to wider use of the Wankel engine. One of the main...
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INNOWACYJNA KONSTRUKCJA UTLENIAJĄCEGO REAKTORA KATALITYCZNEGO UWZGLĘDNIAJĄCA UDZIAŁ WĘGLOWODORÓW W SPALINACH
PublicationObserwowany wzrost świadomości ekologicznej leży u podstaw inicjatyw mających na celu prawne zagwarantowanie ograniczenia uciążliwości dla środowiska wszelkich pojazdów z silnikami spalinowymi. Zaostrzenie norm emisji spalin wymusza poszukiwanie nowych rozwiązań technicznych, szczególnie w zakresie układów oczyszczania spalin. W artykule przedstawiono koncepcję utleniającego reaktora katalitycznego z użyciem nanomateriałów. Naniesienie...
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Small Vessel with Inboard Engine Retrofitting Concepts; Real Boat Tests, Laboratory Hybrid Drive Tests and Theoretical Studies
PublicationThe development of modern technologies and their increasing availability, as well as the falling costs of highly ecient propulsion systems and power sources, have resulted in electric or hybrid propulsions systems’ growing popularity for use on watercraft. Presented in the paper are design and lab tests of a prototype parallel hybrid propulsion system. It describes a concept of retrofitting a conventionally powered nine meter-long...
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PROJEKTOWANIE STANOWISK LABORATORYJNYCH WSPIERAJĄCYCH PROCES SZKOLENIA PRAKTYCZNEGO KADR MORSKICH DZIAŁU MASZYNOWEGO W ŻEGLUDZE MIĘDZYNARODOWEJ, PRZYBRZEŻNEJ I KRAJOWEJ
PublicationWithin the article a design offer of the Department of Ship and Power Plants of the Faculty of Ocean Engineering And Ship Technology at the Gdansk University of Technology has been presented. The offer concerns designing laboratory stations which might stand for the equipment of a didactic base of maritime educational centers i.e. maritime (naval) academies and schools as well as maritime affairs' professional training centers,...
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50’ Sail Catamaran with Hybrid Propulsion, Design, Theoretical and Experimental Studies
PublicationThe development of modern lithium batteries and propulsion systems now allows the use of complex propulsion systems for vessels of various sizes. As part of the research and implementation project, a parallel hybrid drive system was designed, built and then tested in the laboratory. The experimental studies conducted allowed for the measurements of power, fuel consumption and electric power distribution in various operating modes...
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Magnetization Reversal Mechanism in Exchange-Biased Spring-like Thin-Film Composite
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Tracking of the Multimodal Ordering Process in FePd Alloy
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Evolution of Physical Properties of RE 3 Ni 5 Al 19 Family (RE = Y, Nd, Sm, Gd, Tb, Dy, Ho, and Er)
PublicationSingle crystals of RE3Ni5Al19 series (RE = Y, Nd, Sm, Gd, Tb, Dy, Ho, and Er) are grown using the Al self-flux method. The crystal structure is examined by both single crystal and powder X-ray diffraction. Physical properties are studied for the first time for RE3Ni5Al19 (RE = Y, Nd, Gd, Tb, Dy, Ho, and Er) by means of magnetic susceptibility, electrical resistivity, and heat capacity measurements. Complex magnetic behaviors, with...
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Big Data Analytics for ICT Monitoring and Development
PublicationThe expanded growth of information and communication technology has opened new era of digitization which is proving to be a great challenge for researchers and scientists around the globe. The utmost paradigm is to handle and process the explosion of data with minimal cost and discover relevant hidden information in the least amount of time. The buzz word “BIG DATA” is a widely anticipated term with the potential to handle heterogeneous,...
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The Tourism Sector’s Development and Popularization of Sharing Economy. The Impact on Cooperation
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Structural ordering of laser-processed FePdCu thin alloy films
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Magnetotransport Properties of Semi-Metallic Bismuth Thin Films for Flexible Sensor Applications
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Determination of grain shape of laser-irradiated FePdCu thin alloy films
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Mechanical Properties of Different Nanopatterned TiO2 Substrates and Their Effect on Hydrothermally Synthesized Bioactive Hydroxyapatite Coatings
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New Tetragonal ReGa5(M) (M = Sn, Pb, Bi) Single Crystals Grown from Delicate Electrons Changing
PublicationSingle crystals of the new Ga-rich phases ReGa~5(Sn), ReGa~5(Pb) and ReGa~5(Bi) were successfully obtained from the flux method. The new tetragonal phases crystallize in the space group P4/mnc (No. 128) with vertex-sharing capped Re2@Ga14 oblong chains. Vacancies were discovered on the Ga4 and Ga5 sites, which can be understood as the direct inclusion of elemental Sn, Pb and Bi into the structure. Heat capacity measurements were...
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Structure activity relationship for a series of peptidomimetic antimicrobial prodrugs containing glutamine analogues.
PublicationZbadano specyficzność transporterów Dpp i Opp w stosunku do peptydów zawierających FMDP. Przy pomocy modelowania cząsteczkowego zaproponowano najbardziej prawdopodobne struktury konformerów peptydów i skorelowano je z aktywnością przeciwbakteryjną oraz specyficznością transporterów peptydowych.
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Doppler effect in the CW FM sonar
PublicationWhen sonars are used for military purposes they have to ensure unobtrusive operation, a feature that can be potentially secured by 'silent sonar' or continuous wave frequency modulation sonars (CW FM sonars). The article presents how these sonars operate and identifies the relations between their parameters. The Doppler effect and its impact on the CW FM sonar are studied to identify how it affects the sonar's parameters. The results...
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Silent Sonar with matched filtration
PublicationRadars with continuous wave frequency (CW FM sonars) are used in radiolocation as 'silent sonars'. They determine the distance to target by measuring the difference between the frequency of the sounding signal and echo signal. The article presents the principle of operation and parameters of silent CW FM sonars. Target distance determined by these sonars is based on the signal at the output of the matched filter. The Doppler effect...
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Electronic stabilization of beams in sonar with cylindrical array
PublicationArtykuł prezentuje podstawy opisu beamformera dla sonaru z antena cylindryczną. Artykuł pokazuje, że zmodyfikowany beamformer może zostać użyty do stabilizacji osi wiązki w horyzontalnej płaszczyźnie, gdy znany jest przechył i zanurzenie statku. Artykuł przedstawia także problem elektronicznego odchylania wiązki.
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Autonomus hydroacoustics sound velocity profiler.
PublicationPraca zawiera opis bezpośredniej zasady pomiarowej i struktury wersji autonomicznego miernika pomiarów rozkładów prędkości dźwięku w akwenach przeznaczonych do stosowania na okrętach nawodnych, podwodnych i opuszczanych antenach sonarowych śmigłowców i okrętów nawodnych.
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Underwater Navigation Ssystem Based on Doppler Shift – Measurements and Error Estimations
PublicationA new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected...
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Wydawnictwo Adam Marszałek
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Ammonium Hydroxide Mediated Hydrothermal Crystallization of Hydroxyapatite Coatings on Titanium Substrate
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Fabrication of flexible highly ordered porous alumina templates by combined nanosphere lithography and anodization
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Ordered FePdCu nanoisland arrays made by templated solid-state dewetting
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Influence of surface topography on RBS measurements: case studies of (Cu/Fe/Pd) multilayers and FePdCu alloys nanopatterned by self-assembly
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Low-Dimensional Magnetic Semimetal Cr0.65Al1.35Se3
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Crystal structure, chemical bonding, and physical properties of layered AIrSn2 (A = Sr and Ba)
PublicationWe report the experimental and theoretical investigation of structure, chemical bonding interactions, and physical properties of new ternary stannides AIrSn2 (A = Sr and Ba). AIrSn2 (A = Sr and Ba) crystallizes in the orthorhombic Re3B-type structure with the space group Cmcm (No. 64). According to single-crystal X-ray diffraction results, the structure of AIrSn2 (A = Sr and Ba) can be considered as a Zintl-type compound with heterogeneous...
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Mangiferin Has an Additive Effect on the Apoptotic Properties of Hesperidin in Cyclopia sp. Tea Extracts
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Chemical order and crystallographic texture of FePd:Cu thin alloy films
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Influence of Superparamagnetism on Exchange Anisotropy at CoO/[Co/Pd] Interfaces
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