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A three-dimensional periodic beam for vibroacoustic isolation purposes
PublikacjaThis paper presents results of investigations on a three-dimensional (3-D) isotropic periodic beam. The beam can represent a vibroacoustic isolator of optimised dynamic characteristics in the case of its longitudinal, flexural and torsional behaviour. The optimisation process concerned both the widths as well as the positions of particular frequency band gaps that are present in the frequency spectrum of the beam. Since the dynamic...
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Oceny strategiczne elementem systemu łagodzenia w odniesieniu do krajobrazowych skutków komunikacji drogowej
PublikacjaArtykuł prezentuje możliwości wykorzystania strategicznych ocen oddziaływania na środowisko jako jednego z elementów systemu łagodzenia negatywnych skutków rozwoju. Za wiodący aspekt wzmocnienia systemu SOOŚ/OOŚ uznano problem łagodzenia skutków środowiskowych, a najważniejszą w tym rolę przypisano krajobrazowi, określonemu jako nośnik informacji o skutkach w poszczególnych, współzależnych od siebie elementach środowiska i za wyznacznik...
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Characterization of Defects Inside the Cable Dielectric With Partial Discharge Modeling
PublikacjaThe continuous monitoring of power system devices is an important step toward keeping such capital assets safe. Partial discharge (PD)-based measurement tools provide a reliable and accurate condition assessment of power system insulations. It is very common that voids or cavities exist in every solid dielectric insulation medium. In this article, different voids are modeled and analyzed using an advanced finite element (FE)-based...
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CERTIFICATION SYSTEM AS A TOOL FOR IMPROVING THE SAFETY AND SUSTAINABILITY OF SCHOOL-RELATED TRAVELS
PublikacjaDespite the well-established physical, social, emotional, cognitive, and spatial benefits of active and autonomous school commuting of children and adolescents', many are driven by car. Pilot surveys and field research held in 2019 in 10 Gdansk primary schools confirmed this trend. The article presents a certification system for schools, commissioned by the City of Gdańsk, which is an element of a systemic solution shaping patterns...
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Significant Production of Thermal Energy in Partially Ionized Hyperbolic Tangent Material Based on Ternary Hybrid Nanomaterials
PublikacjaNanoparticles are frequently used to enhance the thermal performance of numerous materials. This study has many practical applications for activities that have to minimize losses of energy due to several impacts. This study investigates the inclusion of ternary hybrid nanoparticles in a partially ionized hyperbolic tangent liquid passed over a stretched melting surface. The fluid motion equation is presented by considering the...
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Efficient and robust quadratures for isogeometric analysis: Reduced Gauss and Gauss–Greville rules
PublikacjaThis work proposes two efficient quadrature rules, reduced Gauss quadrature and Gauss–Greville quadrature, for isogeometric analysis. The rules are constructed to exactly integrate one-dimensional B-spline basis functions of degree p, and continuity class C^{p−k}, where k is the highest order of derivatives appearing in the Galerkin formulation of the problem under consideration. This is the same idea we utilized in Zou et al....
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Investigation on the Sources and Impact of Trace Elements in the Annual Snowpack and the Firn in the Hansbreen (Southwest Spitsbergen)
PublikacjaWe present a thorough evaluation of the water soluble fraction of the trace element composition (Ca, Sr, Mg, Na, K, Li, B, Rb, U, Ni, Co, As, Cs, Cd, Mo, Se, Eu, Ba, V, Ge, Ga, Cr, Cr, P, Ti, Mn, Zr, Ce, Zn, Fe, Gd, Y, Pb, Bi, Yb, Al, Nb, Er, Nd, Dy, Sm, Ho, Th, La, Lu, Tm, Pr, Tb, Fe, In, Tl) and their fluxes in the annual snowpack and the firn of the Hansbreen (a tidewater glacier terminating in the Hornsund fjord, southwest...
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Selective H2 production from plastic waste through pyrolysis and in-line oxidative steam reforming
PublikacjaThis study deals with the proposal of pyrolysis and in-line oxidative steam reforming (P-OSR) for plastic waste valorization and assesses the potential of this strategy for the selective production of H2. Overall, the study aims at progressing towards the fine-tuning of the pyrolysis-reforming technology by co-feeding O2. Thus, a multi-point O2 injection system has been developed to ensure a suitable O2 distribution in the reforming...
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Enhanced cellulose extraction from agave plant (Agave americana Species) for synthesis of magnetic/cellulose nanocomposite for defluoridation of water
PublikacjaResearch on fluoride removal from water is currently focusing on the development of innovative materials for defluoridation water. The current study extracted and used enhanced cellulose from Agave americana species to synthesize a magnetic/cellulose nanocomposite for water defluoridation. Strong and light binary acids (H2SO4 and CH3COOH) were utilized to pretreat raw material to enhance cellulose extraction. Central composite...
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Structural, thermal and physico-mechanical properties of polyurethane/brewers’ spent grain composite foams modified with ground tire rubber
PublikacjaIn this work, brewers’ spent grain (BSG) and ground tire rubber (GTR) waste fillers were applied as low-cost reinforcement phase in rigid polyurethane foam (PUR). PUR/BSG/GTR composites were prepared by a single step method, using polyglycerol as partial substitute of commercially available petrochemical polyols. Foaming parameters, chemical structure, dynamic mechanical properties, thermal stability, physico-mechanical properties...
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Assessing ecotoxicity and the endocrine potential of selected phthalates, BADGE and BFDGE derivatives in relation to environmentally detectable levels
PublikacjaThere is no doubt that the subject area of plasticmaterials (e.g., production of epoxy resins or polyesters) is inherently connected to issues concerning bisphenol A (BPA) and its analogues. Unfortunately, much less attention has been given to other compounds, which are also used for the production of these materials. Bisphenol A diglycidyl ether (BADGE) is a synthetic industrial compound obtained by a condensation reaction between...
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Structure versus hydrolytic and thermal stability of bio-based thermoplastic polyurethane elastomers composed of hard and soft building blocks with high content of green carbon
PublikacjaNowadays, sustainability plays a key role in the design and synthesis of new materials. One of the methods for the preparation of green materials is incorporation into their structure the monomers with a high content of green carbon. Therefore, the aim of this work was to investigate the influence of the type and molecular mass of two bio-based polyester polyols and bio-glycol on the properties of aliphatic partially bio-based...
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Can bottom sediments be a prospective fertilizing material? A chemical composition analysis for potential reuse in agriculture.
PublikacjaEvery year huge amounts of bottom sediments are extracted worldwide, which need to be dis-posed. The recycling of bottom sediments for soil fertilization is in line with the long-promoted circular economy policy and enables the use of micro and macronutrients accumulated in sedi-ments for soil fertilization. When considering potential agricultural reuse of the dredge sediments, the first necessary step should be to analyze whether...
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Desulfurization of raw naphtha cuts using hybrid systems based on acoustic cavitation and advanced oxidation processes (AOPs)
PublikacjaA combination of dual-frequency acoustic cavitation (acoustic cavitation) and UV assisted advanced oxidation processes (AOPs) reaction system was developed for desulfurization of raw naphtha used to produce aviation fuels. Various types of oxidants in hybrid systems including hydrogen peroxide, acetic acid, acetone, air and ozone were compared. At optimum oxidant to sulfur compounds molar ratio (rox) of 5.0, the hybrid process...
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Fluorescence Imaging Using Methylene Blue Sentinel Lymph Node Biopsy in Melanoma
PublikacjaIntroduction: Fluorescence imaging of sentinel node biopsy in melanoma is a novel method. Both indocyanine green (ICG) and methylene blue (MB) have fl uorescent properties. The aim of this study was to present, for the fi rst time in a clinical series of patients, the possible usage of MB as a fl uorescent dye for sentinel node biopsy during surgery for melanoma. Material and methods: Twenty patients with...
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Application of a catalytic combustion sensor (Pellistor) for the monitoring of the explosiveness of a hydrogen-air mixture in the upper explosive limit range
PublikacjaA new technique is presented for continuous measurements of hydrogen contamination by air in the upper explosive limit range. It is based on the application of a catalytic combustion sensor placed in a cell through which the tested sample passes. The air content is the function of the quantity of formed heat during catalytic combustion of hydrogen inside the sensor. There is the possibility of using the method in industrial installations...
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A role of an Enterprise Identification Card in a building process of water tourist investments
PublikacjaAn essential element of a building process for water tourist investments in Poland is a document called the Enterprise Identification Card. It is required for the investments, which are classified according to the Regulation [1] as the ones that could potentially impact the environment. It is assumed that KIP is there to protect the environment against the excessive human interference and it just provides the guidelines regarding...
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Gmach Europejskiego Centrum Solidarności - geneza przestrzeni, w poszukiwaniu tożsamości miejsca
PublikacjaBudynek Europejskiego Centrum Solidarności został wzniesiony jako istotny element przestrzeni pamięci – historycznych terenów Stoczni Gdańskiej. W procesie formułowania autorskiego programu architektury szczególną uwagę poświęcono więc odniesieniom do szeroko rozumianego kontekstu kulturowego. Dla dokonania analizy swoistości lokalizacji, jako koniecznego punktu odniesienia dla kreowanej architektury, jej twórca podjął próbę posłużenia...
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Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
PublikacjaThe paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...
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A procedure for elastoplastic hardening function identification.
PublikacjaThe inverse analysis method for identifying a nonlinear hardening function,which governs a plastic yielding of soil and rock materials in the framework of elastoplastic theory is presented. A concept of two stage finite element based on spatial discretization of computational space and hardening function space is introduced. The proposed inverse analysis can be classified as the output least squares method. The Levenberg Marquard...
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Development and performance analysis of a novel multiphase doubly-fed induction generator
PublikacjaThis paper presents the research into the design and performance analysis of a novel five-phase doubly-fed induction generator (DFIG). The designed DFIG is developed based on standard induction motor components and equipped with a five-phase rotor winding supplied from the five-phase inverter. This approach allows the machine to be both efficient and reliable due to the ability of the five-phase rotor winding to operate during...
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Search for the most useful geometry of an acoustic journal bearing
PublikacjaComputer simulations of a number of journal bearing’s geometries utilising acoustic levitation were carried out. The choice of the best geometry depended on the ability of a deformed shape, created by piezo-electric elements, to facilitate squeeze film ultrasonic levitation, and also to create three evenly distributed diverging aerodynamic gaps. Deformations of analysed variants of the bearing’s shape were generated by numerical...
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Modal properties identification of a novel sandwich footbridge – Comparison of measured dynamic response and FEA
PublikacjaA modern sandwich composite footbridge made of high-tech materials, being an example of practical application of laminated composites in civil engineering, is presented. The in situ non-destructive testing of the footbridge, aiming to identify modal properties and pedestrian comfort, is described. The measured eigenmodes and eigenfrequencies are compared with numerically estimated values. Finite element analyses of the footbridge...
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Inspekcje bezpieczeństwa ruchu drogowego
PublikacjaInspekcja drogowa prowadzona pod kątem bezpieczeństwa ruchu drogowego jest narzędziem pozwalającym na identyfikowanie mankamentów sieci drogowej. W artykule przedstawiono ogólne założenia wykonywania inspekcji i jej cele oraz wskazano inspekcję jako element oceny zagrożenia na drogach. Na podstawie inspekcji drogi wojewódzkiej przedstawiono przykłady problemów dotyczących jakości sieci drogowej oraz opisano procedurę wyboru najbardziej...
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Blended Learning in Teaching Safety of Electrical Installations
PublikacjaBlended learning becomes more commonly used in teaching information technology or other subjects, which involve practice in computer laboratories. In case of subjects with no access to computer rooms blended learning supports lecturing and teaching classes e.g. interactive lessons. The article presents the use of blended learning forms in Gdansk University of Technology in teaching the subject of Safety of Electrical Installations....
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Numerical estimation of the pile toe and shaft unit resistances during the installation process in sands
PublikacjaNumerical simulations of a pile jacking were carried out. A Coupled Eulerian–Lagrangian (CEL) formulation was used to treat with large deformation problems. An Abaqus, a commercial Finite Element Method software suit, was used as a computing environment. The Mohr–Coulomb constitutive model was applied and the Coulomb model of friction was used to describe pile-soil interaction. Calculations were made for three different pile diameters....
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Hydrodynamic Pressure Field of a Ship on Shallow Water
PublikacjaResults of calculations of the hydrodynamic pressure field around the ship were obtained by application of the boundary element method. Hydrodynamic field was calculated for a Polish Navy’s tugboat and transport ship using a program called SHiPP and compared with measurements of the field taken on river near Swinoujscie for two identical tugs H-4 and H-10. Next, a series of HPF calculations was carried out on planes situated at...
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SELECTION OF DIAGNOSTIC FUNCTIONS IN A WHEELED TRACTOR
PublikacjaIn a classical approach to damage diagnosis, the technical condition of an analyzed machine is identified based on the measured symptoms, such as performance, thermal state or vibration parameters. In wheeled tractor the fundamental importance has monitoring and diagnostics during exploitation concerning technical inspection and fault element localizations. The main functions of a diagnostic system are: monitoring tractor components...
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Miejsca handlu ulicznego w przestrzeni publicznej
PublikacjaHandel targowy w przestrzeni publicznej współczesnego miasta posiada różnorodne znaczenie, często stawiany jest w dwóch granicznych spojrzeniach, od formy szpecącej daną przestrzeń, po element pożądania w celu przyciągnięcia oka turysty oraz stworzenia atmosfery swojskości w przestrzeni publicznej miasta. W poniższym artykule spróbujemy się przyjrzeć tej drugiej możliwości wykorzystania handlu targowego, jako elementu mogącego...
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Nonlinear FEM 2D failure onset prediction of composite shells based on 6-parameter shell theory
PublikacjaWithin the framework of the nonlinear 6-parameter shell theory with the drilling rotation and asymmetric stress measures, the modifications of Tsai-Wu and Hashin laminate failure initiation criteria are proposed. These improvements enable to perform first ply failure estimations taking into account the non-symmetric stress measures. In order to check the validity of the proposed criteria, finite element analyses are performed with...
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Modification of the operating point of residual current transformers for high frequency earth fault currents detection
PublikacjaFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when earth fault current with high frequency components occurs. Serious hazard of electrocution exists then. One of the most important element of residual current devices is a residual current transformer with iron core. Tripping characteristic of residual current devices strictly...
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A novel sandwich footbridge - Practical application of laminated composites in bridge design and in situ measurements of static response
PublikacjaA novel sandwich composite footbridge is presented in the paper, as an example of practical application of laminated composites in civil engineering. The in situ static load tests of the footbridge before its acceptation for exploitation are shown and discussed. The results are compared with the corresponding ones from a numerical equivalent single layer model of the sandwich structure created within the framework of finite element...
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DOM KASZUBSKI NA ZIEMI ZABORSKIEJ. smaki dziedzictwa
PublikacjaOgólnopolska wystawa plastyczna miała miejsce w Wielu jako element projektu pt. „Smaki ziemi zaborskiej. Dziedzictwo przyrodnicze i kulturowe” zaplanowanego w ramach 19. Europejskich Dni Dziedzictwa. Współorganizatorami byli: Wydział Architektury Politechniki Gdańskiej - Agnieszka Kurkowska,kuratorka ) i Dom Kultury im. H. Derdowskiego w Wielu/ Muzeum Ziemi Zaborskiej. Wystawa tematycznie dotyczyła wysmakowanej architektury...
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Numerical investigations on early indicators of fracture in concrete at meso-scale.
PublikacjaFracture is a major reason of the global failure of concretes. The understanding of fracture is important to ensure the safety of structures and to optimize the material behaviour. In particular an early prediction possibility of fracture in concretes is of major importance. In this paper, concrete fracture under bending was numerically analysed using the Discrete Element Method (DEM). The real mesoscopic structure of a concrete...
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Stress analysis of a strip under tension with a circular hole
PublikacjaThe paper addresses stress analysis of a strip with a circular hole under uniform uniaxial tension based oncircumferential stress expressionρπ. Stresses are analyzed in the infinite-length strips under tension with holes, the ratioof the hole radiusa to the strip half-widthb is either equal to:κ =a/b = 0.1 orκ = 0.5. Circumferential stresses aredetermined in selected cross-sections of the strip. The stress diagrams display local...
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Benchmarking overlapping communication and computations with multiple streams for modern GPUs
PublikacjaThe paper presents benchmarking a multi-stream application processing a set of input data arrays. Tests have been performed and execution times measured for various numbers of streams and various compute intensities measured as the ratio of kernel compute time and data transfer time. As such, the application and benchmarking is representative of frequently used operations such as vector weighted sum, matrix multiplication etc....
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublikacjaApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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A 27/26-approximation algorithm for the chromatic sum coloring of bipartitegraphs
PublikacjaWe consider the CHROMATIC SUM PROBLEM on bipartite graphs which appears to be much harder than the classical CHROMATIC NUMBER PROBLEM. We prove that the CHROMATIC SUM PROBLEM is NP-complete on planar bipartite graphs with Delta less than or equal to 5, but polynomial on bipartite graphs with Delta less than or equal to 3, for which we construct an O(n(2))-time algorithm. Hence, we tighten the borderline of intractability for this...
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Evaluation of sound event detection, classification and localization in the presence of background noise for acoustic surveillance of hazardous situations
PublikacjaAn evaluation of the sound event detection, classification and localization of hazardous acoustic events in the presence of background noise of different types and changing intensities is presented. The methods for separating foreground events from the acoustic background are introduced. The classifier, based on a Support Vector Machine algorithm, is described. The set of features and samples used for the training of the classifier...
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Heat Transfer During Pool Boiling of Water, Methanol and R141b on Porous Coated Horizontal Tube Bundles
PublikacjaThis paper presents the results of experimental investigation of water, methanol and R141b refrigerant boiling on horizontal porous coated tube bundles supposed to represent a flooded-type evaporator. Experiments were carried out for a bundle of 19 tubes in triangular layout for two pitch-to-diameter ratio values – 1.7 and 2.0 – in atmospheric and sub-atmospheric pressure conditions. Average heat transfer coefficients – both local,...
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Thermodynamic analysis of the double Brayton cycle with the use of oxy combustion and capture of CO2
PublikacjaIn this paper, thermodynamic analysis of a proposed innovative double Brayton cycle with the use of oxy combustion and capture of CO2, is presented. For that purpose, the computation flow mechanics (CFM) approach has been developed. The double Brayton cycle (DBC) consists of primary Brayton and secondary inverse Brayton cycle. Inversion means that the role of the compressor and the gas turbine is changed and firstly we have expansion...
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Effect of Tube Bundle Arrangement on the Performance of PCM Heat Storage Units
PublikacjaThe results of comprehensive study on charging and discharging of latent heat storage systems (LHSS) are presented. The multi tube shell-and-tube unit with a variable layouts of the tube bundles are examined. Two tube arrangements – in-line and staggered are tested. A variable number of tubes and different tube positions in a bundle are investigated. Moreover, two pitch ratios are studied. Three commercially available substances...
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Excitation of Circularly Polarized Wave via Single-Feed Metasurface-Integrated Compact Antenna for Internet of Things
PublikacjaA compact circularly polarized (CP) quasi-omnidirectional antenna is introduced for internet of things (IoT). The structure consists of two components implemented on FR-4 substrates, and sep-arated by an air gap: one printed with a rectangular patch fed through a matching network, and another with a metasurface and a ground plane. Two different methods for impedance matching are employed. An equivalent circuit model of the antenna...
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Depolarisation Model for a BAN Indoor Scenario
PublikacjaIn this paper, an analysis of depolarisation in Body Area Networks for Body-to-Infrastructure communications based on a measurement campaign in the 5.8 GHz band in an indoor environment is performed. Measurements were made with an offbody antenna transmitting linearly polarised signals and dualpolarised receiving antennas carried by the user on the body. A Normal Distribution with a mean of 2.0 dB and a standard deviation of 4.3...
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Praktyczne zastosowania analizy wrażliwości na przykładzie projektowania tarczy
PublikacjaW pracy przedstawiono przykłady zastosowania analizy wrażliwości przy projektowaniu tar-czy. Badano wpływ zmian grubości obszarów tarczy – zmiennej projektowej – na przemiesz-czenie wybranego punktu tarczy – zmiennej stanu. Zaproponowano metodę projektowania polegającą na zwiększeniu grubości obszarów tarczy, których wpływ na wariację zmiennej stanu (wrażliwość) jest największa. Do obliczeń numerycznych korzystano z metody elemen-tów...
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Quasi-analytical Near-to-Far Field Transformation Based on Field Matching Method for Scattering Problems
PublikacjaA new quasi-analytical near-to-far field transformation based on field matching method (field expansion in a base of Hankel functions) is presented. This approach uses finite element method to obtain near field, then the field is expressed in a base of Hankel functions. The evaluated coefficients allow to calculate the field outside the numerical domain, also in a far distance. The main advantage of the proposed technique is avoiding of...
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FEM Calculations in Analysis of Steel Subsea Water Injection Flowlines Designing Process
PublikacjaPaper describes the result of theoretical research aimed at assessing the loads and operating conditions of a Coiled Tubing pipeline injecting water, suspended to the mining platform of Lotos Petrobaltic. For this purpose, appropriate calculation models have been developed using the Finite Element Method (FEM), taking into account the nature of the analyzed object and its loads. The analyzes were carried out for two pipes (previously...
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Metody testowania wibracyjnego elementów wynoszonych w przestrzeń kosmiczną
PublikacjaW trakcie wynoszenia ładunku w rakiecie, poddawany jest on wielu obciążeniom, których efektem są m.in. jego drgania. Zanim element zostanie dopuszczony do wylotu, przeprowadzona musi zostać analiza obliczeniowa oraz ładunek musi zostać poddany testom zgodnie z normami. W pracy przedstawiono wstępne obliczenia metodą elementów skończonych, które wykazują, że obciążenia podczas testów są większe niż podczas lotu, co może otwierać...
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Pogłosowości wnętrza sakralnego na przykładzie kościoła pw. Niepokalanego Serca Maryji w Gdyni
PublikacjaWalory słuchowe stanowią obok walorów wizualnych istotny element w postrzeganiu przestrzeni sakralnej. Dlatego dobrze zaprojektowana akustyka wnętrza (lub chociażby uniknięcie podstawowych błędów akustycznych) jest na równi ważna z projektem architektonicznym. Zasadniczym kryterium w ocenie własności akustycznych wnętrz jest jego pogłosowość. W niniejszym referacie przedstawiono analizę i ocenę pogłosowośći wnętrza kościoła przeprowadzoną...
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Experimental study of boiling heat transfer in the stagnation point of water microjet
PublikacjaIn the paper presented is a comparison of computational model with experimental data. Numerical model of liquid film with phase change in the stagnation zone due to impingement of the microjet is more widely presented in authors previous work. The radius on which theevaporation process is taking place can be determined from the energy balance on the element of the plate. That radius has also been confirmed experimentally in the...