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Paweł Możejko dr hab.
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Quantum key distribution based on private states: Unconditional security over untrusted channels with zero quantum capacity
PublikacjaIn this paper, we prove unconditional security for a quantum key distribution (QKD) protocol based on distilling pbits (twisted ebits) from an arbitrary untrusted state that is claimed to contain distillable key. Our main result is that we can verify security using only public communication-via parameter estimation of the given untrusted state. The technique applies even to bound-entangled states, thus extending QKD to the regime...
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Directed percolation effects emerging from superadditivity of quantum networks
PublikacjaEntanglement-induced nonadditivity of classical communication capacity in networks consisting of quantum channels is considered. Communication lattices consisting of butterfly-type entanglement-breaking channels augmented, with some probability, by identity channels are analyzed. The capacity superadditivity in the network is manifested in directed correlated bond percolation which we consider in two flavors: simply directed and...
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Attributes of Entrepreneurial Teams as Elements of a Mental Model
PublikacjaAn entrepreneurial team can be defined as a small group of individuals holding ownership or control positions who create or develop an entrepreneurial venture and have shared commitments towards each other. Entrepreneurial teams start numerous new ventures or affect the performance of firms due to their social capital based on some characteristic attributes. The mental models of teams refer to internal, organised representation...
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Analysis of mixing rules for the Stillinger-Weber potential: a case study of Ge-Si interactions in the liquid phase
PublikacjaCiekły stop Ge_{0.25}Si_{0.75} symulowano metodą dynamiki molekularnej, przy użyciu potencjału Stillingera-Webera. Badano wpływ parametryzacji członu potencjału odpowiedzialnego za oddziaływania trójciałowe w trójkach nieidentycznych atomów na strukturę symulowanego stopu. Wpływ ten okazał się być znaczący.Zmiany w parametrach rzędu kilku procent skutkowały istotnymi różnicami w parowych funkcjach rozkładu, kątowych funkcjach rozkładu...
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Właściwości kompozytów Al-Si-Fe-Cu otrzymanych in situ
PublikacjaPrzeprowadzono badania wybranych właściwości kompozytów o osnowie Al-Si z wydzieleniami fazy AlSi4Fe utworzonej in situ przez mieszanie proszków Fe i Cu z ciekłym stopem Al. Zbadano zachowanie materiału przy ściskaniu, twardość oraz zużycie ścierne w warunkach tarcia suchego o płytkę stalową poruszającą się ruchem posuwisto zwrotnym. Przeanalizowano obrazy SEM powierzchni tarcia oraz przekrojów, w celu określenia mechanizmu zużycia...
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Two-photon double ionization of atoms in attosecond x-ray radiation fields
PublikacjaWe consider two-photon double ionization of helium with 100, 200, and 400 eV excess energy for the two ejected electrons, corresponding to photon energies of 89.5, 139.5, and 239.5 eV, respectively. We focus on the case of ultrashort pulses (two oscillations of the field) and develop an approach to calculate the two-photon transition matrix elements within the lowest order of the time-dependent perturbation theory. One of the...
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Mercury intrusion porosimetry (MIP) results of cement pastes containing iron oxide (Fe3O4) nanoparticles (nanomagnetite)
Dane BadawczeMercury intrusion porosimetry (MIP) data - curves of cement pastes containing iron oxide (Fe3O4) nanoparticles (nanomagnetite) in *.opju (Origin) format.
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OPERATION OF TWO-SHAFT GAS TURBINE IN THE RANGE OF OPEN ANTI-SURGE VALVE
PublikacjaThis paper presents experimental tests of full-scale two-shaft gas turbine in the range of open anti-surge valve (ASV). The tests were carried out in a laboratory gas- turbine test stand belonging to Department of Automation and Power Engineering , Faculty of Ocean Engineering and Ship Technology , Gdańsk University of Technology. The tests covered the start-up and low load operation of the turbine set in the range of open...
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PORTAL Porowaty, kompozytowy stop tytanu o wysokiej odporności na korozję, biozgodności i bioaktywności
ProjektyProjekt realizowany w Wydział Mechaniczny zgodnie z porozumieniem NCBiR/ERA-NET-MATERA/5/2009 z dnia 2009-12-01
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Outlet Flow Velocity In Circular Culvert
PublikacjaThe outlet flow velocity in the end section of the culvert barrel depends in most cases on the culvert geometry, including the barrel slope, as well as on upstream and downstream channel parameters. Flowing water can create pressure flow or free surface flow in the culvert barrel. In the case of an unsubmerged barrel outlet, the free-surface flow is more frequent than the full flow. Increased velocities can cause channel bed scour...
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Quantum-state transfer in spin chains via isolated resonance of terminal spins
PublikacjaWe propose a quantum-state transfer protocol in a spin chain that requires only the control of the spins at the ends of the quantum wire. The protocol is to a large extent insensitive to inhomogeneity caused by local magnetic fields and perturbation of exchange couplings. Moreover, apart from the free evolution regime, it allows one to induce an adiabatic spin transfer, which provides the possibility of performing the transfer...
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Examining Feature Vector for Phoneme Recognition
PublikacjaThe aim of this paper is to analyze usability of descriptors coming from music information retrieval to the phoneme analysis. The case study presented consists in several steps. First, a short overview of parameters utilized in speech analysis is given. Then, a set of time and frequency domain-based parameters is selected and discussed in the context of stop consonant acoustical characteristics. A toolbox created for this purpose...
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WPŁYW CYKLU CIEPLNEGO NA WŁAŚCIWOŚCI ZGRZANYCH WYBUCHOWO ZŁĄCZY STAL-ALUMINIUM
PublikacjaW artykule omówiono budowę, własności oraz technologię wytwarzania trójwarstwowych łączników zgrzewanych wybuchowo typu stal–stop aluminium AlMg. W łącznikach tego typu występuje połączenie stali z aluminium, które decyduje o ich własnościach eksploatacyjnych. Szczególną uwagę zwrócono na proces spawania łączników, który może być przyczyną znaczącego spadku wytrzymałości złączy stal-aluminium. Przedstawiono wyniki badań właściwości...
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Novel topology of compact coplanar waveguide resonant cell low-pass filter
PublikacjaIn this study, a novel pseudoelliptic function low-pass filter (LPF) constituted by a compact coplanar waveguide resonant cell has been designed and manufactured. The lumped-element seven-pole prototype has been adequately realized by using complementary perturbations located both in signal line and ground plane metallization. The fabricated uniplanar LPF offers a compact size of 5.6 x 9.8 mm2, return loss better than 26 dB over...
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Research on the phenomena of warming up and free cooling down the car engine
PublikacjaThe average cold start temperature in Europe is 9 degrees C. However, not the average is the most important for the composition of exhaust gases and associated air pollution. The most onerous for the environment are the winter starts when automotive emissions of harmful gases add up in cities with those of home heating systems. The paper presents preliminary studies of warming up and cooling down processes in various environmental conditions....
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Influence of operation of national experimental nuclear reactor on the natural environment
PublikacjaThis paper presents the impact of experimental nuclear reactor operations on the national environment, based on assessment reports of the radiological protection of active nuclear technology sources. Using the analysis of measurements carried out in the last 15 years, the trends are presented in selected elements of the environment on the Świerk Nuclear Centre site and its surroundings. In addition, the impact of research results...
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Existence and uniqueness of monotone and bounded solutions for a finite-difference discretization a` la Mickens of the generalized Burgers–Huxley equation.
PublikacjaDeparting from a generalized Burgers–Huxley partial differential equation, we provide a Mickens-type, nonlinear, finite-difference discretization of this model. The continuous system is a nonlinear regime for which the existence of travelling-wave solutions has been established previously in the literature. We prove that the method proposed also preserves many of the relevant characteristics of these solutions, such as the positivity,...
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Signals Features Extraction in Radioisotope Liquid-Gas Flow Measurements using Autocorrelation Function
PublikacjaKnowledge of the two-phase flow structure is essential for the proper conduct of industrial processes. Description of liquid-gas flow regimes is possible by using of data analysis in time, frequency, or state-space domain. In this research studies, the autocorrelation function is applied for analysis of signals obtained for liquid-gas flow by use gamma-ray absorption. The experiments were carried out on the laboratory hydraulic...
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Cylindrical orifice testing in laminar flow with the orifice diameter ratio β = 0.5
PublikacjaThe paper presents the results of an experimental study of a cylindrical orifice with the orifice diameter ratio β = 0.5 and the flow opening length‑to‑diameter ratio L/d = 1, with hydraulic oil flowing in the DN50 measuring channel. The measurements of the values characterising the oil flow were made in the laminar flow regime, for the Reynolds numbers ranging between Re = 100 to 950. Based on the experimental tests, standard...
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Effect of temperature and gaseous medium on the structure and microhardness of the cobalt base clad layers
PublikacjaBadano wpływ temperatury utleniania na mikrostrukturę i mikrotwardość napawanych warstw ze stopu kobaltu. Warstwy wytwarzano za pomocą napawania plazmowego (pta) na przylgniach zaworów wylotowych wykonanych ze stali x40CrSiMo10-2. Stop kobaltu był poddany utlenianiu w powietrzu w temperaturach od 750 °C to 1100 °C i w gazach wylotowych w temperaturze 750 °C. W wyniku utleniania zaobserwowano zmanę w mikrotwardości warstw. W zewnętrznej...
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How Chain Transfer Leads to a Uniform Polymer Particle Morphology and Prevents Reactor Fouling
PublikacjaABSTRACT: The effect of adding diethyl zinc as a chain transfer agent during the polymerization of propylene in heptane performed at 80 °C was studied. Although it was expected that the chain transfer would stop after precipitation of the polymer, the polymer molecular weight continued to increase throughout the whole of the polymerization. The presence of diethyl zinc had an additional effect that the polymerizations were devoid...
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The effect of current signal filtering method on the value of cutting power while sawing wood
PublikacjaThe goal of this work was to investigate an effect of various signal pre-processings on the outline of the electrical power curve and its influence on the measured cutting force estimation. Two signal processing methods were selected for the needs of the experiment, including digital filter and wavelet transform. The filter used was Butterworth, 3rd order band-stop with the cut-out band from 45 Hz to 55 Hz. The second approach...
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Do kariery, gotowi, START! - Zawodowcy na mecie
ProjektyProjekt realizowany w Biuro Karier i Absolwentów zgodnie z porozumieniem POWR.03.01.00-00-B027/15 z dnia 2016-06-08
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Analiza właściwości rozszerzonego obserwatora prędkości maszyny indukcyjnej
PublikacjaRozszerzony obserwator prędkości został zaproponowany przez prof. Krzemińskiego i jest oparty na rozszerzonym modelu maszyny indukcyjnej, gdzie wprowadzona został nowa zmienna ζ. Jest to nowe podejście do estymacji zmiennych stanu maszyny indukcyjnej i nie wszystkie problemy zostały do tej pory rozwiązane. Zaproponowano wykorzystanie algorytmów ewolucyjnych do doboru wzmocnień obserwatora. W celu redukcji nakładów obliczeniowych...
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Environmental characteristics of a tundra river system in Svalbard. Part 1: Bacterial abundance, community structure and nutrient levels
PublikacjaThe Arctic hosts a set of unique ecosystems, characterised by extreme environmental conditions and undergoing a rapid change resulting from the average temperature rising. We present a study on an aquatic ecosystem of the Revelva catchment (Spitsbergen), based on samples collected from the lake, river and their tributaries, in the summer of 2016. The landscape variety of the study site and the seasonal change in the hydrological...
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Andrzej Okuniewski dr inż.
OsobyWykształcenie 2010-2014: Katedra Chemii Nieorganicznej, Wydział Chemiczny, Politechnika Gdańskadoktor nauk chemicznych (nauki chemiczne – chemia, chemia nieorganiczna) 2009-2010: Wydział Chemiczny, Politechnika Gdańskamagister chemii (chemia stosowana) 2005-2009: Wydział Chemiczny, Politechnika Gdańskainżynier chemik (chemia stosowana) 2002-2005: II Liceum Ogólnokształcące im. Władysława Pniewskiego w Gdańskuprofil biologiczno-chemiczno-fizyczny...
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A new method of wind farm active power curve estimation based on statistical approach
PublikacjaThe purpose of this paper is to solve the wind farm active power estimation problem, introducing the method which is based on a statistical approach and robust fitting. The proposed algorithm uses a statistical approach and compared to existing ones- includes a wind direction as well as the influence of turbine start-up procedure on the estimation. The results show that additional estimation inputs i.e. the wind direction and the...
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Systematic Literature Review on Click Through Rate Prediction
PublikacjaThe ability to anticipate whether a user will click on an item is one of the most crucial aspects of operating an e-commerce business, and clickthrough rate prediction is an attempt to provide an answer to this question. Beginning with the simplest multilayer perceptrons and progressing to the most sophisticated attention networks, researchers employ a variety of methods to solve this issue. In this paper, we present the findings...
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Interaction of Acoustic and Thermal Modes in the Gas with Nonequilibrium Chemical Reactions: Possibilities of Acoustic Cooling
PublikacjaNonlinear generation of thermal mode during propagation of dominative sound in a chemically reacting gas is considered. The dynamic equation of excess temperature associated with the thermal mode is derived. It is instantaneous and includes quadratic nonlinear acoustic source reflecting the nonlinear character of interaction between acoustic and non-acoustic types of gas motion. Both periodic and aperiodic sound may be considered...
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Interaction of Acoustic and Thermal Modes in the Vibrationally Relaxing Gases. Acoustic Cooling
PublikacjaThe dynamic equation which governs an excess temperature associated with the thermal mode in vibrationally relaxing gas is derived. The nonlinear transfer of acoustic energy to the energy of the thermal mode in a relaxing gas causes slow variation of temperature with time. The nal dynamic equation is instantaneous. All types of sound, including aperiodic, may be considered as an acoustic source of corresponding heating or cooling....
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Kagome Lattice Promotes Chiral Spin Fluctuations
PublikacjaDynamical spin fluctuations in magnets can be endowed with a slight bent toward left- or right-handed chirality by Dzyaloshinskii-Moriya interactions. However, little is known about the crucial role of lattice geometry on these chiral spin fluctuations and on fluctuation-related transport anomalies driven by the quantum-mechanical (Berry) phase of conduction electrons. Via thermoelectric Nernst effect and electric Hall effect experiments,...
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Context-aware User Modelling and Generation of Recommendations in Recommender Systems
PublikacjaRecommender systems are software tools and techniques which aim at suggesting new items that may be of interest to a user. This dissertation is focused on four problems in recommender systems domain. The first one is context-awareness, i.e. how to obtain relevant contextual information, how to model user preferences in a context and use them to make predictions. The second one is multi-domain recommendation, which aim at suggesting...
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Recent Advances in Loop Heat Pipes with Flat Evaporator
PublikacjaThe focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle)...
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Recovery of Anammox Biomass at Short Hydraulic Retention Time in a MBR Reactor
PublikacjaThe anammox system has been consider as an economical option for treating high concentration of nitrogen and poor in biodegradable orgaednic carbon wastewaters. This process is attractive option compared with conventional nitrogen removal because it provides a significant saving in aeration and organic addition for denitrification. The anammox technology has been applied mostly for concentrated nitrogenous wastewater containing...
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High temperature corrosion resistance of porous hastelloy alloy
PublikacjaTo further understand the suitability of Ni-Cr-base alloy for solid oxide fuel cell (SOFC), a commercial Ni-Cr-Fe-Mo alloy, Hastelloy X was selected and evaluated for oxidation behaviour under high temperature conditions. HastelloyX was chosen due to its unusual resistance to oxidizing, reducing and neutral atmospheres. For long term stability of metal supported fuel cell, the corrosion resistance plays a vital role and must be...
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Tagged images with bees 3
Dane BadawczeImages taken from bee hive with tagged bees. The images are random frames from movies recorded in may 2017 and 2018. All images are taken from full HD video stream.
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BEZCZUJNIKOWE STEROWANIE WOLNOOBROTOWYM SILNIKIEM PMSM Z KOMPENSACJĄ MOMENTU ZACZEPOWEGO
PublikacjaW pracy przedstawiono propozycję rozwiązania problemu bezczujnikowego sterowania wolnoobrotową maszyną synchroniczną z magnesami trwałymi PMSM. Przedstawiono silnik PMSM, który zastosowano w stanowisku badawczym. Omówiono problem występowania tętnień momentu napędowego wynikający głównie ze znacznego momentu zaczepowego. Pokazano rozwiązanie kompensujące tętnienia momentu napędowego w silniku PMSM. Przygotowano procedurę startową...
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Detection of vehicles stopping in restricted zones in video from surveillance cameras
PublikacjaAn algorithm for detection of vehicles that stop in restricted areas, e.g. excluded by traffic rules, is proposed. Classic approaches based on object tracking are inefficient in high traffic scenes because of tracking errors caused by frequent object merging and splitting. The proposed algorithm uses the background subtraction results for detection of moving objects, then pixels belonging to moving objects are tested for stability....
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Real-Time Basic Principles Nuclear Reactor Simulator Based on Client-Server Network Architecture with WebBrowser as User Interface
PublikacjaThe real-time simulator of nuclear reactor basic processes (neutron kinetics, heat generation and its exchange, poisoning and burn- ing up fuel) build in a network environment is presented in this paper. The client-server architecture was introduced, where the server is a pow- erful computing unit and the web browser application is a client for user interface purposes. The challenge was to develop an application running under the...
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Energy Loss Coefficients ki in a Displacement Pump and Hydraulic Motor used in Hydrostatic Drives
PublikacjaThe article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating...
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MONITORING OF PERMANENT GPS STATIONS AT THE SUDETY MOUNTAINS
PublikacjaThe aim of this paper is to show time-dependent baseline variation between GPS stations situated in South-East Poland. This study was based on daily data analysis of selected GPS stations: WROC, GOPE, MOPI, KRAW and KATO. The start date of the analysis is linked at every station with the beginning of its operation and the closing date of the operation is in 2006. The multiresolution signal decomposition method has been used to...
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START-UP HEROES Platforma startowa dla nowych pomysłów
ProjektyProjekt realizowany w Katedra Mechaniki i Mechatroniki zgodnie z porozumieniem 14/SH/2018
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Paweł Czarnul dr hab. inż.
OsobyPaweł Czarnul uzyskał stopień doktora habilitowanego w dziedzinie nauk technicznych w dyscyplinie informatyka w roku 2015 zaś stopień doktora nauk technicznych w zakresie informatyki(z wyróżnieniem) nadany przez Radę Wydziału Elektroniki, Telekomunikacji i Informatyki Politechniki Gdańskiej w roku 2003. Dziedziny jego zainteresowań obejmują: przetwarzanie równoległei rozproszone w tym programowanie równoległe na klastrach obliczeniowych,...
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Chemistry and Nanochemistry 2023
Kursy OnlineWe start from General Chemistry, including: calculus in chemistry, bonds, balancing the chemical reactions, redox reactions, electrochemistry, pH, acids, bases, salts, oxides, organic molecules, and many informations about synthesis, analysis and applications in nanochemistry.
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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HYDROGEN PRODUCTION PERFORMANCE IN THERMOCATALYTIC REACTOR BASED ON THE INTERMETALLIC PHASE OF NI3AL
PublikacjaThe main aim of the following paper is mathematical modelling for momentum, heat and mass transfer, which is accompanied by chemical surface reactions of the flow of the mixture helium and methanol. The thermocatalytic devices used for decomposition of hydrocarbons incorporate vertical microchannels coupling at the ends and heated to 500 oC at the walls. The results of the experiment were compared with CFD calculations to calibrate...
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Can unequal distributions of wealth influence vote choice? A comparative study of Germany, Sweden and the United States.
PublikacjaIt is widely accepted that income influences voting behavior. Does wealth? Is the effect similar across countries? Studies of wealth and voting behavior have not existed until recently, in part because of the absence of data on wealth holdings. The findings in this chapter indicate that wealth is related to voting behavior in some countries but not in others. The chapter models the effects of wealth on one form of voting behavior,...
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Ultrashort Opposite Directed Pulses Dynamics with Kerr Effect and Polarization Account
PublikacjaWe present the application of projection operator methods to solving the problem of the propagation and interaction of short optical pulses of different polarizations and directions in a nonlinear dispersive medium. We restrict ourselves by the caseof one-dimensional theory, taking into account material dispersion and Kerr nonlinearity. The construction of operators is delivered in two variants: for the Cauchy problem and for the...
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„Gdański eksperyment” studentów PG poleci rakietą z Europejską Agencją Kosmiczną
PublikacjaPięcioosobowy zespół studentów Politechniki Gdańskiej, który przyjął nazwę HEDGEHOG (High quality Experiment Dedicated to microGravity Exploration, Heat flow and Oscillation measurement from Gdansk), zakwalifikował się do programu REXUS/BEXUS Student Experiment Programme koordynowanego przez Europejską Agencję Kosmiczną (ESA). W lutym 2018 roku studenci polecą do kosmodromu Esrange nieopodal Kiruny w północnej Szwecji, by poszerzyć...