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Search results for: CROSS-POLARISATION DISCRIMINATION
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Intercultural Challenges in Virtual Teams
Publication: Virtual teams are usually geographically dispersed and consist of members from different countries and cultures. They influences internal communication processes and can cause personal conflicts, misunderstandings or lack of trust. Intercultural diversity is also significant for goal setting and team effectiveness. The aim of this article is to check if virtual team members appreciate the cultural diversity or rather suffer from lack...
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Dissociative electron attachment to benzoic acid (C7H6O2)
PublicationThe dissociative electron attachment (DEA) to benzoic acid (C6H5COOH) has been studied using an experimental crossed beam setup of a quadrupole mass spectrometer and a trochoidal electron monochromator. Relative partial cross sections for the DEA to produce negative ion fragments show the main channels for dissociation. The comparison of the present results with the ultraviolet photoelectron spectrum of benzoic acid [J. Meeks,...
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A new look at the statistical identification of nonstationary systems
PublicationThe paper presents a new, two-stage approach to identification of linear time-varying stochastic systems, based on the concepts of preestimation and postfiltering. The proposed preestimated parameter trajectories are unbiased but have large variability. Hence, to obtain reliable estimates of system parameters, the preestimated trajectories must be further filtered (postfiltered). It is shown how one can design and optimize such...
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Shell model of multiple-row moment I-section end-plate joint
PublicationThe paper deals with a problem of application of shell elements in the models of multiple-row moment end-plate connections. The extended connection of I-section with a cross-section W760x265x220 made of steel S355 was analyzed. Comparison analysis of FEM, complex volume and shell models has been done. Three cases with different end-plate thickness: 14, 18 and 36 mm were analyzed and compared with the reference results. Comparison...
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Stress analysis of a strip under tension with a circular hole
PublicationThe 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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Genotyping Techniques for Determining the Diversity of Microorganisms
PublicationTyping of microbial pathogens, or identifying bacteria at the strain level, is particularly important for diagnosis, treatment, and epidemiological surveillance of bacterial infections. This is especially the case for bacteria exhibiting high levels of antibiotic resistance or virulence, and those involved in nosocomial or pandemic infections. Strain typing also has applications in studying bacterial population dynamics. The part...
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Optimally regularized local basis function approach to identification of time-varying systems
PublicationAccurate identification of stochastic systems with fast-varying parameters is a challenging task which cannot be accomplished using model-free estimation methods, such as weighted least squares, which assume only that system coefficients can be regarded as locally constant. The current state of the art solutions are based on the assumption that system parameters can be locally approximated by a linear combination of appropriately...
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Locally Adaptive Cooperative Kalman Smoothing and Its Application to Identification of Nonstationary Stochastic Systems
PublicationOne of the central problems of the stochastic approximation theory is the proper adjustment of the smoothing algorithm to the unknown, and possibly time-varying, rate and mode of variation of the estimated signals/parameters. In this paper we propose a novel locally adaptive parallel estimation scheme which can be used to solve the problem of fixed-interval Kalman smoothing in the presence of model uncertainty. The proposed solution...
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The Effectiveness of Polymer Damper in Damage Reduction of Temporary Steel Grandstand
PublicationA large number of accidents involving damage of temporary grandstands during different types of events were observed in the past. The aim of the paper is to analyse numerically the effectiveness of a polymer damper in damage reduction of a temporary steel scaffolding grandstand exposed to dynamic load due to jumping. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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Experimental and numerical study on polymer element used for reduction of temporary steel grandstand vibrations
PublicationThe purpose of the paper is to analyse the effectiveness of a polymer damper in reduction of a temporary steel grandstand vibrations through the experimental and numerical study. The damper considered in the investigation is constructed out of two L-shape steel members bonded with polymer mass of high damping properties. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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Wykorzystanie algorytmu kompresji sygnału mowy MP-LPC do modelowania przebiegu fonokardiograficznego
PublicationW artykule przedstawiono nową metodę modelowania dźwięków serca, która może znaleźć zastosowanie w systemach diagnostyki urządzeń medycznych oraz stanowić podstawę opracowania inteligentnego stetoskopu. Przedstawiona propozycja stanowi rozwinięcie algorytmu MP-LPC wykorzystywanego w kompresji sygnału mowy. Wykazano, że do dokładnego modelowania przebiegu fonokardiograficznego, który pozwala na odwzorowywanie różnorodnych stanów...
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Using concentrated spectrogram for analysis of audio acoustic signals
PublicationThe paper presents results of time-frequency analysis of audio acoustic signals using the method of Concentrated Spectrograph also known as ''Cross-spectral method'' or ''Reassignment method''. Presented algorithm involves signal's local group delay and channelized instantaneous frequency to relevantly redistribute all Short-time Fourier transform lines in time-frequency plain. The main intention of the paper is to compare various...
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Digitalization and digital skills development patterns. Evidence for European countries
PublicationThis chapter contextualizes the digitalization process and the digital skills concept. It discusses the very process of technology diffusion, emphasizing several unique features of digital technologies that make them globally available. Next, it turns to the digital skills concept, clarifying how and why they reshape the societal and economic landscape. It also briefly addresses the digital divide and skill-biased technological...
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Buckling of thin-walled columns accounting for initial geometrical imperfections
PublicationThe paper is devoted to the effect of some geometrical imperfections on the critical buckling load of axially compressed thin-walled I-columns. The analytical formulas for the critical torsional and flexural buckling loads accounting for the initial curvature of the column axis or the twist angle respectively are derived. The classical assumptions of theory of thin-walled beams with non-deformable cross-sections are adopted. The...
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Pedestrian safety in road traffic – studies, recommendations and proposed improvements
PublicationPedestrians are involved and most frequently the victims of every third road accident in Poland. Pedestrian accidents most frequently occur in complex circumstances, as a result of many factors related to the behaviour of drivers and pedestrians. The basic parameters that determine road safety include the perception of traffic and visibility on the road. The paper will present the results of research conducted within the project...
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RSS-Based DoA Estimation in 802.11p Frequency Band Using ESPAR Antenna and PPCC-MCP Method
PublicationIn this paper, the concept of direction of arrival (DoA) estimation using electronically steerable parasitic array radiator (ESPAR) antenna designed to operate in IEEE 802.11p vehicular communication standard has been investigated with respect to different possible elevation angles of a radio frequency (RF) signal impinging the antenna. To this end, two different possible sets of the 3D antenna radiation patterns have been used...
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Analysis of the Application of Horizontal Directional Drilling
PublicationConstruction works are often considered to be very intrusive for the environment. Project designers assume deep excavations, or a complete replacement of the ground within the investment, which sometimes changes the initial conditions drastically. The problem started to appear in places, where the terrain is complicated and the excavation is burdensome. Some of state authorities...
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Structural and mechanical properties of hydroxyapatite coatings formed by ion-beam assisted deposition
PublicationThe ion-beam assisted deposition (IBAD) is an advanced method capable of producing crystalline coatings at low temperatures. We determined the characteristics of hydroxyapatite Ca10(PO4)6(OH)2 target and coatings formed by IBAD using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX). The composition of the coatings'...
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Modelling of subarachnoid space width changes in apnoea resulting as a function of blood flow parameters
PublicationDuring apnoea, the pial artery is subjected to two opposite physiological processes: vasoconstriction due to elevated blood pressure and vasorelaxation driven by rising pH in the brain parenchyma. We hypothesized that the pial artery response to apnoea may vary, depending on which process dominate. Apnoea experiments were performed in a group of 19 healthy, non-smoking volunteers (9 men and 10 women). The following parameters...
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Assessing unsignalised pedestrian crossings
PublicationThe lack of pedestrian safety on crossings is a complex problem and one that is influenced by a number of factors such as the law, road traffic culture, the road and traffic. This paper will focus on the last two by presenting a method for assessing pedestrian crossings for their geometry and roadside using data from 930 pedestrian crossings in Warsaw. The authors of this paper have attempted to systematise the process of assessment...
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Flavones in cocoa defence against Phytophthora megakarya
PublicationCross-pollination of suitable genotypes and earlier selection of elite offspring using adequate plants-associated defence markers in plantlets leaves are decisive for development of T. cacao genotypes tolerant to black pods disease (BPD). T. cacao plantlets from manual cross-pollination of ♀SNK64 × ♂UPA143 were analyzed for their susceptibility to BPD using leaf disc test. Subsequently, leaves (healthy, wounded and wound+infected)...
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Agnieszka Pastula Dr
PeopleAgnieszka received her masters degree in biology at Jagiellonian University (Poland). Besides standard university classes, she did multiple extracurricular research internships in both basic science and medical life sciences e.g. at Warsaw University, Jagiellonian University College of Medicine, University of Medical Sciences in Poznań and University Medical Center Utrecht, that provided her with excellent interdisciplinary training...
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Identyfikacja trajektorii obiektów dynamicznych w przestrzeni kartezjańskiej na podstawie informacji z wielu estymatorów stanu
PublicationW rozprawie przedstawiono metodologię umożliwiającą implementację rozproszonego asynchronicznego systemu wyznaczania trajektorii. System tego typu jest złożony ze zbioru tzw. węzłów (estymatorów lokalnych), które komunikują się ze sobą. Każdy węzeł wyznacza trajektorię obserwowanego obiektu/procesu na podstawie dwóch zbiorów danych. Pierwszym zbiorem są pomiary dostarczane przez skojarzone z danym...
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Estimation of the Ultimate Strength of FRP Strips-to-Masonry Substrates Bond
PublicationFiber-Reinforced Polymers (FRP) were developed as a new method over the past decades due to their many beneficial mechanical properties, and they are commonly applied to strengthen masonry structures. In this paper, the Artificial Neural Network (ANN), K-fold Cross-Validation (KFCV) technique, Multivariate Adaptive Regression Spline (MARS) method, and M5 Model Tree (M5MT) method were utilized to predict the ultimate strength of...
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Electrolytic deposition of reactive element thin films on Crofer 22 APU and evaluation of the resulting high-temperature corrosion protection properties at 700 °C–900 °C
PublicationThis article presents electrolytic deposition of thin Rare Earth (RE) coatings on Crofer 22 APU stainless steel substrates for high temperature applications, such as interconnects in solid oxide cell stacks. The deposition of coatings based on yttrium-, gadolinium-, lanthanum-, and cerium nitrates is discussed. The high temperature corrosion properties of surface-modified steels were examined using thermogravimetry and electrical...
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A Bayesian regularization-backpropagation neural network model for peeling computations
PublicationA Bayesian regularization-backpropagation neural network (BRBPNN) model is employed to predict some aspects of the gecko spatula peeling, viz. the variation of the maximum normal and tangential pull-off forces and the resultant force angle at detachment with the peeling angle. K-fold cross validation is used to improve the effectiveness of the model. The input data is taken from finite element (FE) peeling results. The neural network...
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Recent Developments in Data-Assisted Modeling of Flexible Proteins
PublicationMany proteins can fold into well-defined conformations. However, intrinsically-disordered proteins (IDPs) do not possess a defined structure. Moreover, folded multi-domain proteins often digress into alternative conformations. Collectively, the conformational dynamics enables these proteins to fulfill specific functions. Thus, most experimental observables are averaged over the conformations that constitute an ensemble. In this...
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Quality Evaluation of Novel DTD Algorithm Based on Audio Watermarking
PublicationEcho cancellers typically employ a doubletalk detection (DTD) algorithm in order to keep the adaptive filter from diverging in the presence of near-end speech signal or other disruptive sounds in the microphone signal. A novel doubletalk detection algorithm based on techniques similar to those used for audio signal watermarking was introduced by the authors. The application of the described DTD algorithm within acoustic echo cancellation...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part I: Steady-state processes
PublicationThe article presents a possible method of detecting failures in the flow section and supply system of a naval gas turbine engine based on the exhaust gas temperature measured behind the gas generator. This temperature is a basic diagnostic parameter use for evaluating the technical state of the turbine engine in operation, and is monitored during engine start-ups, accelerations and decelerations of rotor units, and steady-load...
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High temperature corrosion of evaporator tubes with thermal sprayed coatings
PublicationDegradation examinations of outer surface of low-emission steam boiler evaporator tubes are presented in the paper. Metallographic evaluation of scale morphology, its micro sites chemical composition analysis and distribution of elements on cross sections have been performed. Water-wall tubes were exposed in steam boiler for up to two years period. Common tubes made of 16Mo3 steel suffered sulphide and molten salts corrosions....
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Corrosion of evaporator tubes in low emission steam boilers
PublicationPurpose of this paper is to reveal the mechanisms of corrosion processes of outer surfaces of low-emission steam boiler evaporator tubes. Examinations were performed to find the reasons of different corrosion susceptibility of tubes situated at combustion chamber on various levels. Examinations were conducted on several segments of 57 x 5.0 mm evaporator tubes made of 16M (16Mo3) steel grade. Segments were taken from level of...
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Ocena dokładności określania osi toru kolejowego na drodze pomiarów satelitarnych
PublicationW 2009 roku na Politechnice Gdańskiej rozpoczęto badania nad wykorzystaniem serwisu pomiarów fazowych NAVGEO aktywnej sieci geodezyjnej ASG-EUPOS dla przeprowadzania ciągłych pomiarów przebiegu trasu kolejowej. Celem kontynuowanych badań jest próba oceny możliwości zastosowania pomiarów fazowych GNSS, realizowanych przez kilka odbiorników, dla projektowania oraz inwentaryzacji toru kolejowego. Do oceny dokładności określenia osi...
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Linear and branched polyester resins based on dimethyl-2,5-furandicarboxylate for coating applications
PublicationIn this study, novel bio-based hydroxyl-functional (co)polyesters from dimethyl-2, 5-furandicarboxylate (DMF), 2,3-butanediol, and a variety of comonomers viz. glycerol, pentaerythritol or trimethylolpropane are prepared using a solvent-free, bulk polycondensation technique. Extensive molecular and thermal characterization was performed to elucidate the properties of these materials. The materials showed suitable properties for solvent-borne...
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Quality evaluation of agricultural distillates using different types of electronic noses
PublicationThe paper presents the results of investigation on quality evaluation of agricultural distillates using a prototype of electronic nose instrument and a commercial electronic nose of Fast/Flash GC type – HERACLES II. The prototype was equipped with TGS type semiconductor sensors. HERACLES II included two chromatographic columns with different polarity of stationary phase and two FID detectors. In case of the prototype volatile fraction...
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Electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations of ethyl acetate
PublicationThe high-resolution vacuum ultraviolet photoabsorption spectrum of ethyl acetate, C4H8O2, is presented over the energy range 4.5−10.7 eV (275.5−116.0 nm). Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Also, the photoabsorption cross sections...
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Induced sheath voltages in 110 kV power cables – case study
PublicationThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...
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Export diversification and economic development: a dynamic spatial data analysis
PublicationThis paper contributes to the empirical literature on the relationship between ‘export variety’ (export diversification) and economic development by relaxing the assumption of cross-country independence and allowing for spatial diffusion of shocks in observed and unobserved factors. Export variety is measured for a balanced panel of 114 countries (1992-2012) using very detailed information on their exports (HS 6-digit product...
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The Magnetic Fluid Seals Research Results vs. Kelvin-Helmholtz (K-H) instability and Preliminary Conclusions
PublicationIn the article a magnetic-fluid seals durability research and the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are: critical pressure, critical motion velocity and...
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Evolutionary approach to ship's trajectory planning within Traffic Separation Schemes
PublicationThe paper presents the continuation of the author's research on evolutionary approach to ship trajectory planning. While the general problem of the evolutionary trajectory planning has already been solved, no one has yet touched one of its specific aspects: evolutionary trajectory planning within Traffic Separation Schemes. Traffic Separation Scheme (TSS) is a traffic-management route-system complying with rules of the International...
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Considerations of Computational Efficiency in Volunteer and Cluster Computing
PublicationIn the paper we focus on analysis of performance and power consumption statistics for two modern environments used for computing – volunteer and cluster based systems. The former integrate computational power donated by volunteers from their own locations, often towards social oriented or targeted initiatives, be it of medical, mathematical or space nature. The latter is meant for high performance computing and is typically installed...
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Recent Advances in Graphene Oxide-Based Membranes for Heavy Metal Ions Separation
PublicationGraphene oxide (GO)-based membranes have been widely investigated for separation of dyes, salt ions, heavy metal ions, and biomolecules due to their high mechanical strength, single-layered structure, large surface area, and high affinity. However, due to irregular pore structure, nanochannels, interlayer distance, easy functionalization, swelling effect, and chemical stability under aqueous environment limited their separation...
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The accuracy assessment of determining the axis of railway track basing on the satellite surveying
PublicationW 2009 roku na Politechnice Gdańskiej rozpoczęto badania nad wykorzystaniem serwisu pomiarów fazowych NAVGEO aktywnej sieci geodezyjnej ASG-EUPOS dla przeprowadzania ciągłych pomiarów przebiegu trasu kolejowej. Celem kontynuowanych badań jest próba oceny możliwości zastosowania pomiarów fazowych GNSS, realizowanych przez kilka odbiorników, dla projektowania oraz inwentaryzacji toru kolejowego. Do oceny dokładności określenia osi...
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Application of multicriteria decision analysis to assess the greenness of molecularly imprinted polymers synthesis components
PublicationThe study applies multicriteria decision analysis (MCDA) to rank the components of molecularly imprinted polymers (MIPs) synthesis according to their greenness. The components are taken from papers that are describing synthesis of MIPs for persistent organic pollutants (POPs) sorbents. Functional monomers (n = 14), target/surrogate molecules (n = 10), porogens (n = 8), cross-linking agents (n = 8) and initiators (n = 4) are described...
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Role of methylation in electron scattering on X(CH3)4 (X= C, Si, Ge) molecules (2)
PublicationTo investigate how replacement of H atom with methyl group (CH3) – in tetrahedral compounds of carbon, silicon and germanium – affects electron scattering process, total cross sections (TCS) for electron scattering from C(CH3)4, Si(CH3)4 and Ge(CH3)4 molecules have been compared with data for CH4, SiH4 and GeH4 molecules. All examined data have been obtained with the same experimental setup. The shape of all discussed TCS energy...
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5-Bromo-2′-deoxycytidine—a potential DNA photosensitizer
PublicationA double-stranded oligonucleotide, 80 base pairs in length, was multiply labeled with 5-bromo-2′-deoxycytidine (BrdC) using polymerase chain reaction (PCR). The modified oligonucleotide was irradiated with 300 nm photons and its damage was assayed by employing DHPLC, LC-MS and denaturing polyacrylamide gel electrophoresis (PAGE). Two types of damage were demonstrated, namely, single strand breaks (SSBs) and intrastrand cross-links...
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Influence of ESPAR antenna radiation patterns shape on PPCC-based DoA estimation accuracy
PublicationIn the article, we show the influence of three different electronically steerable parasitic array radiator (ESPAR) antenna radiation patterns on the overall direction of arrival (DoA) estimation accuracy when power-pattern cross-correlation (PPCC) algorithm, relying on received signal strength (RSS) values, is used for the estimation. The ESPAR antenna designs were obtained for three optimization goals, which resulted in different...
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RSS-Based DoA Estimation for ESPAR Antennas Using Support Vector Machine
PublicationIn this letter, it is shown how direction-of-arrival (DoA) estimation for electronically steerable parasitic array radiator (ESPAR) antennas, which are designed to be integrated within wireless sensor network nodes, can be improved by applying support vector classification approach to received signal strength (RSS) values recorded at an antenna's output port. The proposed method relies on ESPAR antenna's radiation patterns measured...
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Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations
PublicationThe high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3–10.8 eV (290–115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured...
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INFLUENCE OF TACK WELDS DISTRIBUTION AND WELDING SEQUENCE ON THE ANGULAR DISTORTION OF TIG WELDED JOINT
PublicationIn this paper the influence of tack welds distribution and welding sequence on angular distortion of the Tungsten Inert Gas (TIG) welded joint was tested. Additionally, the effect of welding current on angular distortion was assessed. For research X2CrTiNb18 (AISI 441) stainless steel (2.5 mm thick) was chosen. During research specimens were prepared with different distributionsof tack...
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A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
PublicationThis letter presents a design of a linear phase microwave bandpass filter. The filter is composed of four resonators arranged in the quadruplet topology. Making the cross and one direct coupling dispersive gives additional design flexibility. The first advantage of using frequency-dependent couplings is the possibility to chose an arbitrary location of a pair of complex transmission zeros (TZs) in the s-domain. The second one is...
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Selected Stability Problems of Thin-Walled Columns and Beams
PublicationThe article reviews a number of papers in the light of buckling analy- sis of thin-walled columns and beams. Stability of thin-walled columns and beams are considered a vital engineering science issue in both historical and present-day approaches. The paper refers to the recent authors’ works of the 2012–2019 period, published in leading journals. Similar review of stability problems of thin-walled structures developed at Gdansk...
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Piotr Dominiak prof. dr hab.
PeopleHe was born in Radom on June 29, 1948. He graduated in Economy at the University of Warsaw (1971), where he also obtained his doctorate (1976) and his habilitation (1989). He received the title of Professor in 2005. He has been working at GUT since 1971. Between 1991 and1993 he was a director of the Institute of Economic Sciences and Humanities at GUT. He was the Dean of the Faculty of Management and Economics in the years 1993-1999...
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Chapter 11 – Application of Chemical Sensors and Sensor Matrixes to Air Quality Evaluation
PublicationIndoor and outdoor air quality is one of the key factors influencing human health. However, air quality evaluation is not easy task. Air is a complex system, which is subjected to changes even within short period of time. Progress in analytical methods and analytical tools provides increasingly more reliable information on the condition and quality of indoor and outdoor air. This progress, however, generates an increase in the...
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Polish Polar Research: Green-and-White Paper under the aegis of the Polish Polar Consortium (PPC)
PublicationPolar research is a colloquial term for cross-area, cross-domain and interdisciplinary research in the Arctic and Antarctic. Polar research is mainly the domain of natural sciences, but technical sciences and humanities also grow in importance. Being vulnerable to climate change, polar regions are commonly considered as a kind of litmus paper of changes in geosystems, hence the importance of research done there. It aims at a better...
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Mechanical strength of stems in aquatic macrophytes
PublicationSummary: In populations of submerged macrophytes, individuals are selected in terms of resistance to the effect of hydrodynamic forces. The aim of this study was to check whether individuals growing in river water are more tensile and bending resistant than plants occurring in places not exposed to flow stress. We determined the ultimate tensile strength of stems in four macrophyte species, Potamogeton natans, P. pectinatus, Batrachium...
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Safety issues referred to induced sheath voltages in high-voltage power cables – case study
PublicationLoad currents and short-circuit currents in high-voltage power cable lines are sources of the induced voltages in the power cables’ concentric metallic sheaths. When power cables operate with single-point bonding, which is the simplest bonding arrangement, these induced voltages may introduce an electric shock hazard or may lead to damage of the cables’ outer non-metallic sheaths at the unearthed end of the power cable line. To...
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Wojciech Sadowski prof. dr hab. inż.
PeopleWojciech Sadowski (born 2 February 1954 in Ostaszewo, Poland), scientist, engineer, professor at Gdansk University of Technology, specialist in solid state body physics, nanotechnology, optoelectronics. In 1973 he completed his high school education at High School Nicolaus Copernicus in Chelmno. In 1979 he graduate from Leningrad Electrotechnical Institute in Russia (former Soviet Union) with specialism in dielectrics and semiconductors....
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Precipitation of calcium carbonate in the presence of rhamnolipids in alginate hydrogels as a model of biomineralization
PublicationThis paper reports the effects of rhamnolipids presence in the alginate hydrogel and CO32- solution, on the precipitation of CaCO3 in the Ca2+ loaded alginate hydrogel. Characteristics of the formed particles are discussed. Model conditions containing alginate hydrogel and rhamnolipids were used in order to mimic the natural environment of biomineralization in biofilms. It has been shown that rhamnolipids affect the characteristics...
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Multi-domain and Context-Aware Recommendations Using Contextual Ontological User Profile
PublicationRecommender Systems (RS) became popular tools in many Web services like Netflix, Amazon, or YouTube, because they help a~user to avoid an information overload problem. One of the types of RS are Context-Aware RS (CARS) which exploit contextual information to provide more adequate recommendations. Cross-Domain RS (CDRS) were created as a response to the data sparsity problem which occurs when only few users can provide reviews or...
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Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings
PublicationThis article reports the design of coupled-resonatorbased microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an...
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Modelling of Longitudinal Elastic Wave Propagation in a Steel Rod Using the Discrete Element Method
PublicationThe paper deals with the issue of modelling elastic wave propagation using the discrete element method (DEM). The case of a longitudinal wave in a rod with a circular cross-section was considered. A novel, complex algorithm consisting of the preparation of models and simulation of elastic waves was developed. A series of DEM models were prepared for simulations, differing in discretisation and material parameters. Additional calculations...
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Fabrication of toughened plastic using styrene butadiene rubber-poly (methyl methacrylate) interpenetrating polymer networks
PublicationA standard set of interpenetrating polymeric networks (IPNs) has been contrived using an elastomerstyrene butadiene rubber and a thermoplastic poly (methyl methacrylate) through sequential polymerization protocol. This low-cost material can be hopefully engaged as a toughened plastic with cocontinuous morphology. Different morphological protocols including Raman imaging are effectively utilized to envisage the effect of blend ratio...
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A hyperelastic model for soils with stress-induced and inherent anisotropy
PublicationIn this paper, modelling of the superposition of stress-induced and inherent anisotropy of soil small strain stiffness is8presented in the framework of hyperelasticity. A simple hyperelastic model, capable of reproducing variable stress-induced9anisotropy of stiffness, is extended by replacement of the stress invariant with mixed stress–microstructure invariant to10introduce constant inherent cross-anisotropic component. A convenient...
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Validation study on a new semi-empirical method for the prediction of added resistance in waves of arbitrary heading in analyzing ship speed trial results
PublicationThis paper describes an open and extensive validation study carried out by the Specialist Committee on Ships in Operation at Sea (SOS) of the International Towing Tank Conference (ITTC) on the newly developed SHOPERA-NTUA-NTU-MARIC (SNNM) wave-added resistance prediction method. The SNNM method aims at a simple, fast and transparent determination of the added resistance in regular waves of arbitrary encounter directions, even when...
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Navigational decision support system during approach manoeuvre in emergency STS transfer operation
PublicationThe paper is concerned with the problem of safe trajectory planning for approaching during emergency STS (Ship to Ship) transfer operation with oil spill. The safe trajectory means that the way points does not cross in the area of the environment with the static and dynamic obstacles and at the same time satisfies ship's stopping and speed deceleration performance. The evolutionary path planning algorithm is used to determine trajectory...
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Structures for parameterization, meshing and data exchange of topologically related surfaces of a ship hull
PublicationThis paper presents proposal of data structures for storage and processing of a parametric three-dimensional model of a midship hull sections. The model consists of coarse surfaces like: decks, frames, girders, stiffeners, brackets, partitions etc. bounded by topological relations. All workshop details are omitted as the model is intended for numeric calculations. Proposed data structures are prepared to facilitate changes in the...
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Białowieża primeval forest as an example of transfrontier co-operation between Poland and Bielarus
PublicationThe Polish Ministry of Foreign Affairs is completing their work on the agreement on local border traffic (May 2009.) At the final stage of the works, the list of the towns and villages situated within the area covered by the so-called "local traffic" on both the Polish and the Belarusian sides of the border is being verified. The "border belt" area, whose residents will be able to move between the bordering countries under the...
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Sounding of Layered Marine Bottom - Model Investigations
PublicationThe necessary actions connected with interpretations of examining of physical properties of sea bottom structure is developing of proper procedure of modeling of the layered structure. The implementation of the acoustic waves for the determination of seabed stratification requires a precise diagnosis of the topic from both the theoretical and practical side. Little differences between the parameters of sediments, as well as irregular...
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Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations
PublicationThe highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies...
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Fast surrogate-assisted simulation-driven design of compact microwave hybrid couplers
PublicationThis work presents a robust methodology for expedited simulation-driven design optimization of compact microwave hybrid couplers. The technique relies on problem decomposition, and a bot-tom–up design strategy, starting from the level of basic building blocks of the coupler, and finishing with a tuning procedure that exploits a fast surrogate model of the entire structure. The latter is constructed by cascading local response surface...
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Nanoparticles displacement analysis using optical coherence tomography
PublicationOptical coherence tomography (OCT) is a versatile optical method for cross-sectional and 3D imaging of biological and non-biological objects. Here we are going to present the application of polarization sensitive spectroscopic OCT system (PS-SOCT) for quantitative measurements of materials containing nanoparticles. The PS-SOCT combines the polarization sensitive analysis with time-frequency analysis. In this contribution the benefits...
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Inverse surrogate models for fast geometry scaling of miniaturized dual-band couplers
PublicationRe-design of microwave structures for various sets of performance specifications is a challenging task, particularly for compact components where considerable electromagnetic (EM) cross-couplings make the relationships between geometry parameters and the structure responses complex. Here, we address geometry scaling of miniaturized dual-band couplers by means of inverse surrogate modeling. Our approach allows for fast estimation...
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Morphology and local chain structure of polyamide 6 modified in the solid state with a semi-aromatic nylon salt
PublicationStructural and conformational differences between the polyamide 6 (PA6) homopolymer and two copolymers of PA6 modified in the solid state with 20 and 30 wt% of the semi-aromatic nylon salt of 1,5-diamino-2-methylpentane (Dytek A) and isophthalic acid (IPA) in the feed were investigated. Room temperature wide-angle X-ray diffraction (WAXD) analysis together with 13C{1H} cross-polarization/magic-angle spinning solid-state (CP/MAS)...
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Nagranie formy muzycznej w systemie stereofonii dookólnej
PublicationCelem pracy była realizacja nagrania kwintetu jazzowego w wybranych systemach stereofonii wielokanałowej. Dodatkowym celem było przeprowadzenie testów subiektywnych zrealizowanych nagrań. W pracy zawarto w pierwszej kolejności zagadnienia związane z przestrzenną lokalizacją źródeł dźwięku przez człowieka. W dalszej części przywołane zostały wybrane techniki mikrofonowe stereofonii wielokanałowej, a także metody prowadzenia testów...
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Inline Waveguide Filter With Compact Frequency-Dependent Coupling Producing Two Additional Poles and Three Transmission Zeros
PublicationThis work reports a compact frequency-dependent coupling (FDC) structure introduced in a rectangular waveguide, which allows to generate two additional in-band transmission poles and three transmission zeros (TZs). This serves to increase the order/selectivity of the waveguide bandpass filter in a compact inline topology, thus without the need for any additional space/volume or cross coupling. The proposed FDC consists of a partial-height...
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An annotated timeline of sensitivity analysis
PublicationThe last half a century has seen spectacular progresses in computing and modelling in a variety of fields, applications, and methodologies. Over the same period, a cross-disciplinary field known as sensitivity analysis has been making its first steps, evolving from the design of experiments for laboratory or field studies, also called ‘in-vivo’, to the so-called experiments ‘in-silico’. Some disciplines were quick to realize the...
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Generalized Chebyshev Bandpass Filters With Frequency-Dependent Couplings Based on Stubs
PublicationThis paper presents an accurate synthesis method for inline and cross-coupled generalized Chebyshev bandpass filters with frequency-dependent couplings implemented via open and short stubs. The technique involves the synthesis of a lumped-element prototy pe in the form of a coupling matrix with a frequency-dependent term and the conversion of this prototype to a distributed-element mode l composed of sections of TEM lines. This...
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Estimation of the Maximum Permissible PV Power to be Connected to the MV Grid
PublicationIn recent decades, a significant increase in the share of renewable energy sources in power grids at various voltage levels has been observed. A number of articles have been published highlighting emerging problems in low-voltage grids with a large share of prosumers and in medium- and high-voltage grids to which photovoltaic (PV) plants are connected. The article analyzes the medium-voltage grid in terms of the possibility of...
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Global Digital Technology Convergence: Driving Diffusion via Network Effects
PublicationSince the 1970s, we have witnessed unprecedented diffusion of digital technologies in both speed and geographic coverage. These technologies are pervasive and disruptive, and lead to profound shifts and transformations in societies and economies. Many claim that emerging network externalities are the principal phenomenon driving the process of technology diffusion and determining its in-time dynamics. This book analyses the unique...
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Smart Blue Cities
PublicationThis paper presents the concept of Smart Cities from the perspective of those located by water, considering if there are more major differences in the way the concept is implemented in coastal cities, as opposed to those located anywhere else. It proves possible to point to such differences, in relation to the three key areas of mobility, the environment and living. Further consideration is given to specific legal and cross-cultural...
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Rotational state-changing collisions of C2H− and C2N− anions with He under interstellar and cold ion trap conditions: A computational comparison
PublicationWe present an extensive range of quantum calculations for the state-changing rotational dynamics involving two simple molecular anions that are expected to play some role in the evolutionary analysis of chemical networks in the interstellar environments, C2H− (X1Σ+) and C2N− (X3Σ−), but for which inelastic rates are only known for C2H−. The same systems are also of direct interest in modeling selective photo-detachment experiments...
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Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublicationThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
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Accurate PPCC-Based DoA Estimation Using Multiple Calibration Planes for WSN Nodes Equipped with ESPAR Antennas
PublicationIn this paper, we have introduced a new direction-of-arrival (DoA) estimation method, which relies on received signal strength (RSS) values measured at the output port of electronically steerable parasitic array radiator (ESPAR) antenna and uses the power pattern cross-correlation (PPCC) estimator. In the method, we have successfully incorporated measurements of ESPAR antenna's radiation patterns performed at multiple calibration...
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Synthesis and polymerisation techniques of molecularly imprinted polymers
PublicationMolecularly Imprinted Polymers (MIPs) are materials that has been processed using the molecular imprinting technique which permit to obtain well-defined three-dimensional cavities, with affinity to a template molecule, in the polymer matrix. Technology involves three strategies, i.e., covalent, non-covalent and semi-covalent approach, but the most popular is non-covalent approach. The most important components for the synthesis...
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Determination of dryout localization using a five-equation model of annular flow for boiling in minichannels
PublicationDetailed studies have suggested that the critical heat flux in the form of dryout in minichannels occurs when the combined effects of entrainment, deposition, and evaporation of the film make the film flow rate go gradually and smoothly to zero. Most approaches so far used the mass balance equation for the liquid film with appropriate formulations for the rate of deposition and entrainment respectively. It must be acknowledged...
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CFD-based evaluation of current-carrying capacity of power cables installed in free air
PublicationEvaluation of current-carrying capacity of power cables and selection of cross-sectional area of their conductors are mainly performed in accordance with requirements of EN, IEC or IEEE standards. However, these standards do not provide all methods of cables installation and location which occur in practice. Thus, in some cases, performance of advanced modeling of various thermal phenomena, affecting power cables current-carrying...
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Modelling of residential sales price with kriging using different distance metrics in different correlation functions
PublicationThe modelling and estimation of sales prices based on economical conditions are important for housing sector especially in developing countries. Analysts are focused on the subject to analyze price movements and estimate the future trend of the sales prices for housing sector. In this study, we tried to generate a robust and efficient model related to the subject. Firstly, we investigated economic variables affecting housing sales...
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Assessment of the devulcanization process of EPDM waste from roofing systems by combined thermomechanical/microwave procedures
PublicationEthylene-propylene-diene rubber (EPDM) is a elastomer widely used in common industrial applications. EPDM can be shaped into sheets and employed as isolating material for roofing systems. In this study, scraps of EPDM from commercial, industrial and residential roofing systems were treated by combined thermo-mechanical and microwave devulcanization processes including peroxide of benzoyl (BPO). The devulcanized EPDM (Dev-EPDM)...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results. Part II Results of life tests of multi-stage magnetic - fluid seal operating in water
PublicationThe edge criteria for magnetic-fluid seals durability research were described in previous article [24] and now the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are:...
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Dynamic tests of composite footbridge segment – experimental and numerical studies
PublicationExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
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POSITIVE PSYCHOLOGICAL CAPITAL ENHANCES THRIVING IN THE MULTICULTURAL WORK ENVIRONMENT OF MULTINATIONAL CORPORATIONS
PublicationThe aim of the paper is to examine positive psychological capital (PsyCap) as well as individual factors in the relationship with thriving in the multicultural work environment of multinational corporations (MNCs). We conducted a quantitative study on the sample of 127 individuals from subsidiaries of various MNCs located in Poland and involved in intercultural interactions. The results of cross-sectional study show that employees...
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Managing change through team building in the context of organizing Erasmus+ mobility projects at the Gdańsk Tech Library
PublicationThe article discusses managing change through team building in the context of organizing Erasmus+ mobility projects in the Gdańsk University of Technology Library as the main strategy which contributed to the projects’ success. The authors describe the projects realized in the years 2017-2019 within the scope of the Erasmus+ programme. The organizers decided to take a responsible and active approach towards managing change and...
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Dariusz Mikielewicz prof. dr hab. inż.
PeopleProfessor Dariusz Mikielewicz – born on February 6, 1967. in Gdansk. Here in 1974 he enrolled first to the Elementary School No. 17, and then in the Grammar School No. 5, named after Stefan Żeromski in Gdansk-Oliwa. After graduating from the Secondary School, with honors, in 1985 he successfully passed the entrance exams to the Faculty of Mechanical Engineering of Technical University of Gdansk, where he graduated with a very good...
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"Raport z wstępnych badań własności stali trudnościeralnej 460HB",. ang "Report on preliminary tests of the properties of wear-resistant steel 460HB"
PublicationMikrostrukturę badanej stali trudnościeralnej 460HB stanowi drobnoziarnisty martenzyt odpuszczony, który jest właściwy dla stali konstrukcyjnych niskowęglowych, niskostopowych ulepszonych cieplnie. W przypadku blach grubych, do których zalicza się badana stal, struktura może ulec zaburzeniu, jeżeli w hutniczym procesie wytwórczym wystąpiła niejednorodność odkształcenia plastycznego i w konsekwencji tworzenie się pasm segregacyjnych,...
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Design of High-Performance Scattering Metasurfaces through Optimization-Based Explicit RCS Reduction
PublicationThe recent advances in the development of coding metasurfaces created new opportunities in realization of radar cross section (RCS) reduction. Metasurfaces, composed of optimized geometries of meta-atoms arranged as periodic lattices, are devised to obtain desired electromagnetic (EM) scattering characteristics. Despite potential benefits, their rigorous design methodologies are still lacking, especially in the context of controlling...
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Youth Civic Participation in the South Baltic Region. Example of Lithuania, Poland and Sweden
PublicationThe aim of this study was to show youth civic participation as a social inclusion element in the Southern Baltic region in need of reinforcement, based on the examples of selected municipalities from Lithuania, Poland and Sweden. The authors focused on the diagnosis of key elements of youth civic engagement at local and cross-border level, taking into account the context of national youth policies and the European Union policy....
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Fungal Typin Methods
PublicationThe broad application of the molecular techniques in mycoses diagnosis is related to increase of infections caused by fungi in many countries. The oldest typing methods relaying on fenotypic observation, physiological and biochemical examination have had very limited importance from decades. Novadays, the molecular biology methods took their place. Most of the genotyping methods have been devoleped to be applied for typing of bacteria...
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Application of Rapid Prototyping technology in the manufacturing of turbine blade with small diameter holes
PublicationThe article presents the possibilities of using Rapid Prototyping (RP) technology in the manufacturing of turbine blades with small diameter holes. The object under investigation was gas turbine blade with small diameter cooling holes and holes for generating longitudinal vortices. A turbine blade model was produced by means of Direct Metal Laser Sintering (DMLS) technology and subsequently validated in terms of detection and accuracy...
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Resonances and Dissociative Electron Attachment in HNCO
PublicationIn a combined experimental and theoretical study, we probe the dissociative electron attachment in isocyanic acid HNCO. The experimental absolute cross section for the NCO− fragment shows a sharp onset and fine structures near the threshold. The autoionizing state responsible for the dissociative attachment is found in both the R-matrix calculation and using analytic continuation in the coupling constant. The involved A' resonance...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublicationIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...