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Low-cost multi-objective optimization of antennas using Pareto front exploration and response features
PublikacjaIn the paper, a procedure for low-cost multi-objective optimization of antenna structures is presented. Our approach is based on exploration of the Pareto front representing the best possible trade-offs between conflicting objectives, here, the structure size and its electrical performance. Starting from the design representing the best in-band reflection level, subsequent Pareto-optimal designs are identified through local constrained...
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Acute Effects of Supra- and High-Loaded Front Squats on Mechanical Properties of Lower-Limb Muscles
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Rapid Multi-Criterial Antenna Optimization by Means of Pareto Front Triangulation and Interpolative Design Predictors
PublikacjaModern antenna systems are designed to meet stringent performance requirements pertinent to both their electrical and field properties. The objectives typically stay in conflict with each other. As the simultaneous improvement of all performance parameters is rarely possible, compromise solutions have to be sought. The most comprehensive information about available design trade-offs can be obtained through multi-objective optimization...
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On Fast Multi-objective Optimization of Antenna Structures Using Pareto Front Triangulation and Inverse Surrogates
PublikacjaDesign of contemporary antenna systems is a challenging endeavor, where conceptual developments and initial parametric studies, interleaved with topology evolution, are followed by a meticulous adjustment of the structure dimensions. The latter is necessary to boost the antenna performance as much as possible, and often requires handling several and often conflicting objectives, pertinent to both electrical and field properties...
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Constrained multi-objective optimization of compact microwave circuits by design triangulation and pareto front interpolation
PublikacjaDevelopment of microwave components is an inherently multi-objective task. This is especially pertinent to the design closure stage, i.e., final adjustment of geometry and/or material parameters carried out to improve the electrical performance of the system. The design goals are often conflicting so that the improvement of one normally leads to a degradation of others. Compact microwave passives constitute a representative case:...
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Rapid multi-objective design of integrated on-chip inductors by means of Pareto front exploration and design extrapolation
PublikacjaIdentification of the best trade-offs between conflicting design objectives allows for making educated design decisions as well as assessing suitability of a given component or circuit for a specific application. In case of inductors, the typical objectives include maximization of the quality factor and minimization of the layout area, as well as maintaining a required inductance at a given operating frequency. This work demonstrates...
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Multi-objective optimization of compact UWB impedance matching transformers using Pareto front exploration and adjoint sensitivities
PublikacjaIn this paper, a technique for fast multi-objective optimization of impedance matching transformers has been presented. In our approach, a set of alternative designs that represent the best possible trade-offs between conflicting objectives (here, the maximum reflection level within a frequency band of interest and the circuit size) is identified by directly exploring the Pareto front. More specifically, the subsequent Pareto-optimal...
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Changes in foot pressure on the ground during mae-geri kekomi (front kick) in karate athlete - case study
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The structure and influence of different flying high front kick techniques on the achieved height on the example of taekwon-do athletes
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Study on effective front region thickness of PCM in thermal energy storage using a novel semi-theoretical model
PublikacjaThermal energy storage in mobile applications, particularly battery of electric vehicles, is currently gaining a lot of importance. In this paper, a semi-theoretical time-dependent mathematical model of the phase change in a double shell thermal energy storage module has been developed where the inner tube is a heat exchange surface. An effective front region thickness for the melting and solidification process has been studied....
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Recent advances in rapid multiobjective optimization of expensive simulation models in microwave and antenna engineering by Pareto front exploration
PublikacjaPractical engineering design problems are inherently multiobjective, that is, require simultaneous control of several (and often conflicting) criteria. In many situations, genuine multiobjective optimization is required to acquire comprehensive information about the system of interest. The most popular solution techniques are populationbased metaheuristics, however, they are not practical for handling expensive electromagnetic...
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Experimental study of the impact of notches and holes made in the front edge of adherends on the properties of static and fatigue strength of adhesive joints
PublikacjaThe paper presents the results of experimental studies aimed at determining the effect of holes and notches at the front edge of adherends on the strength of adhesive joints. Single-lap joints made of S235JR steel sheets joined with Araldite 2014-2 epoxy adhesive were tested. Comparative tests of static strength in the shear test as well as high-cycle fatigue strength tests were carried out. Joints with three holes with a diameter...
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Balancing energy consumption in limited power grid with active front-end and three phase dual active bridge system
PublikacjaPaper deals with simulation analysis of bidirectional power converters system for charging station of electric vehicle in condition of limited power source in city infrastructure. In case of incapability to provide additional power supply through the grid by virtue of historical, architectural and economic reasons it is possible to solve this issue by implementation of mobile battery-powered supply source. The proposed bidirectional...
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EM-Driven Size Reduction and Multi-Criterial Optimization of Broadband Circularly-Polarized Antennas Using Pareto Front Traversing and Design Extrapolation
PublikacjaMaintaining small size has become an important consideration in the design of contemporary antenna structures. In the case of broadband circularly polarized (CP) antennas, miniaturization is a challenging process due to the necessity of simultaneous handling of electrical and field properties (reflection, axial ratio, gain), as well as ensuring sufficient frequency range of operation, especially at the lower edge of the antenna...
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Front Cover: Chiral Molecular Cages Based on Cyclotriveratrylene and Sucrose Units Connected with p ‐Phenylene Linkers (Eur. J. Org. Chem. 6/2021)
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Zarys przemian przestrzennych strefy reprezentacyjnej Gdańska na podstawie opracowań planistycznych od 1866 roku
PublikacjaStrefa Reprezentacyjna obejmuje obszar pokrywający się w dużej mierze z zachodnim frontem historycznego śródmieścia Gdańska. Wykształcona na przełomie XIX i XX wieku jako wielkomiejskie centrum miasta jest jedną z historycznie najbardziej kluczowych jego przestrzeni. Dziś to obszar zaniedbany i jakby zapomniany, zdominowany przez funkcje komunikacyjne, jakkolwiek nadal o dużym i niewykorzystanym potencjale. Przemiany przestrzenne...
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Expedite EM-driven generation of Pareto-optimal trade-off curves for variable-turn on-chip inductors
PublikacjaThis work presents a novel approach to computationally efficient Pareto front identification for variable-turn on-chip inductors. The final outcome is a set of solutions that correspond to the best trade-offs between conflicting design objectives. Here, we consider minimising inductor area and, simultaneously, maximising its quality factor, while maintaining a specified inductance value at a given operating frequency. As opposed...
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Mathematical Approach to Assess a Human Gait
PublikacjaA purpose of the paper was to create a mathematical approach to assess a human gait. The scope of the study was to model a normal gait in the sagittal plane and frontal plane of the body. Applying the Newton-Euler formulation, three multibody biomechanical models were derived to describe single support phase and double support phase of the gait. To model a gait in the sagittal plane the open-close sagittal 6DOF model and the open-close...
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Wywiezione w 1945 roku książki wracają do Biblioteki Politechniki Gdańskiej
PublikacjaBiblioteka PG otrzymała od Uniwersytetu w Bremie 15 woluminów książek, które powróciły na naszą uczelnię po tym, jak zostały z niej wywiezione w styczniu 1945 roku z obawy przed zbliżającym się frontem wojennym.
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The Provenance of Selected Sheet Music of Warsaw Publishers (1875-1918) in the Main Library of the Stanisław Moniuszko Academy of Music (Gdańsk)
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Provenance of selected sheet music published by Warsaw publishers between 1875 and 1918, stored in the Main Library of the Stanislaw Moniuszko Academy of Music in Gdańsk as a result of interwar and postwar artistic relations between the centres
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Organy/struktury sui generis w obszarze Przestrzeni Wolności, Bezpieczeństwa i Sprawiedliwości Unii Europejskiej
PublikacjaW przeszłości współpraca państw europejskich w zakresie bezpieczeństwa wewnętrznego ograniczona była rygorystyczne przestrzegana zasadą suwerenno0ści. Tytuł V TFUE reguluje zagadnienia dotyczące Przestrzeni Wolności, Bezpieczeństwa i Sprawiedliwości. W jej ramach funkcjonują organy i struktury sui generis m. in. COSI, SCIFA, FRONTEX, EASO, Eurojust, EJN, OLAF, Europol, CEPOL a także działają w ramach swoich kompetencji ogólne instytucje...
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Pomiary energii pękania złączy klejonych z elastyczną warstwą kleju
PublikacjaPraca dotyczy opracowywania nowych metod badań adhezji elastycznych klejów, na przykładzie akrylowego kleju "mastic" i porównawczo kleju epoksydowego, w oparciu o mechanikę pękania. Artykuł przedstawia wyniki badań przeprowadzonych dla złącza asymetrycznego, czyli np. składającego się z dwóch różnych materiałów lub tych samych materiałów o różnej grubości. Metody wyznaczania podstawowych parametrów w próbach mechaniki pękania przeprowadzanych...
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Port jachtowy jako specyficzny typ zagospodarowania miejskiej strefy nadwodnej
PublikacjaW wyniku przemian zachodzących w strukturach miejskich frontów wodnych oraz zaktualizowania poglądów na temat projektowania i funkcjonowania przestrzeni publicznej jakie nastąpiły w epoce poprzemysłowej, morskie porty jachtowe zaczęły pojawiać się w najbardziej atrakcyjnych rejonach miast nadmorskich. Ich potencjał centrotwórczy jest coraz częściej zauważany i wykorzystywany w procesach transformacji obszarów poportowych, w...
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Współczesne przekształcenia miast portowych w świetle wzmocnienia ich potencjału turystycznego
PublikacjaArtykuł odnosi się do kwestii transformacji frontów wodnych miast portowych w kontekście rozwoju funkcji turystycznej. Zawarto w nim omówienie szeregu studiów przypadku obszarów nadwodnych poddawanych procesom transformacji.
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Kształtowanie architektury terenów sąsiadujących ze śródlądowymi korytarzami wodnymi w aspekcie zrównoważonego rozwoju.
PublikacjaCel pracy przewiduje przedefiniowanie reguł kształtowania architektury śródlądowych frontów wodnych z uwzględnieniem charakteru miejsca lokalizacji inwestycji (kontekst miejsca, kontekst społeczny, kontekst gospodarczo-ekonomiczny); identyfikację zagrożeń i szans wynikających z nowego podejścia do kształtowania frontów wodnych. Rozpatrywane w niniejszej pracy tezy to:1. Zróżnicowanie charakteru zabudowy śródlądowych frontów wodnych...
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Formation and Growth of the Crack in Bonded Joints Under Mode I Fracture: Substrate Deflection at Crack Vicinity
PublikacjaAdhesive bonding is now commonly used in aircraft, cars, boats, etc. In these applications, thin panels are often bonded. In such thin structures, heterogeneous mechanical loading along the bondline edge (or potential crack front), is likely to arise due to 3D structural effects. The crack front and its vicinity is a special region, in that it is where structural properties of the adherend material meet those of the adhesive (discontinuity)....
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The impact of domestic and foreign competition on sectoral growth: a cross-country analysis
PublikacjaThis paper examines the impact of competition on the total factor productivity (TFP) of 21 manufacturing sectors in eighteen OECD countries over the period of time 1990–2006. We assume that the source of TFP growth can be either domestic or foreign innovation or technology transfer from the technological frontier. Trade openness, R&D, and human capital can have two effects: a direct effect on TFP (e.g., through innovation) and...
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An evaluation and explanation of (in)efficiency in higher education institutions in Europe and the U.S. with the application of two-stage semi-parametric DEA
PublikacjaIn this study the technical efficiency of number of public European and American HEIs is assessed over a decade. Efficiency scores are determined using nonparametric DEA with different input-output sets and considering different frontiers: global frontier (all HEIs pooled together), regional frontier (Europe and the U.S. having their own frontiers) and country-specific ones. The external factors affecting the degree of HEI inefficiency...
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A Generalized SDP Multi-Objective Optimization Method for EM-Based Microwave Device Design
PublikacjaIn this article, a generalized sequential domain patching (GSDP) method for efficient multi-objective optimization based on electromagnetics (EM) simulation is proposed. The GSDP method allowing fast searching for Pareto fronts for two and three objectives is elaborated in detail in this paper. The GSDP method is compared with the NSGA-II method using multi-objective problems in the DTLZ series, and the results show the GSDP method...
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Rapid multi-objective antenna design using point-by-point Pareto set identification and local surrogate models
PublikacjaAntenna design is inherently a multicriterial problem.Determination of the best possible tradeoffs between conflicting objectives (a so-called Pareto front), such as reflection response, gain, and antenna size, is indispensable from the designer’s point of view, yet challenging when high-fidelity electromagnetic (EM) simulations are utilized for performance evaluation. Here, a novel and computationally...
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Influence of H2S on degradation of 9Cr-1Mo steel in advanced stage of metal dusting process
PublikacjaPrzedstawiono wyniki badań stali 9Cr-1Mo w zaawansowanym stadium procesu pylenia metalu po 10 latach eksploatacji w piecu rafineryjnej instalacji platformingu CCR, przeprowadzonych w celu podjęcia decyzji o dozowaniu związków siarki do wsadu instalacji. Na podstawie długotrwałej ekspozycji próbek stali w 600C w mieszaninie wodoru i siarkowodoru wykazano, że siarka może być powodem procesów wpływających niekorzystnie na stan materiału...
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A New Approach of Solidification Analysis in Modular Latent Thermal Energy Storage Unit Based on Image Processing
PublikacjaThe solidification process of RT18HC in a cylindrical shell and tube storage unit has been studied using a new methodology based on image processing. The main idea of the algorithm is to label the region of solidification and use statistical functions to calculate the dimensions of the solidification front over time. Said analysis includes two methods. The first method is to measure the solid fraction changes during solidification....
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Fast Multi-Objective Aerodynamic Optimization Using Sequential Domain Patching and Multifidelity Models
PublikacjaExploration of design tradeoffs for aerodynamic surfaces requires solving of multi-objective optimization (MOO) problems. The major bottleneck here is the time-consuming evaluations of the computational fluid dynamics (CFD) model used to capture the nonlinear physics involved in designing aerodynamic surfaces. This, in conjunction with a large number of simulations necessary to yield a set of designs representing the best possible...
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Isostructural zinc and cadmium silanethiolates with bridging biimidazole co-ligands – Enhanced luminescence of zinc complex
PublikacjaTwo dinuclear complexes of zinc and cadmium with silanethiolate and bridging biimidazole ligands are characterized by X-ray diffraction, FT-IR, UV–Vis and emission spectroscopies. The complexes 1 (Zn) and 2 (Cd) are isostructural but exhibit different electronic structures and different character of frontier HOMO orbitals as indicated by DFT calculations. Lluminescence studies prove strong emission properties of zinc complex.
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Joint Analysis of National Eco-Efficiency, Eco-Innovation and SDGs in Europe: DEA Approach
PublikacjaThe growing complexity and intertwining of different socio-economic issues both in individual countries and internationally mean that single-theme analyses do not consider all the relationships and thus have cognitive limitations. Therefore, studies that combine several research areas are increasingly common in the literature to clarify the connections and relationships. In this study, considering the sequential nature of the...
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Cementite transformation in low carbon steel under the influence of sulphur.
PublikacjaBadano cementyt (węglik Fe3C) w przemysłowym gatunku stali niskowęglowej po długotrwałej eksploatacji w benzynie ciężkiej, zawierającej 0,3 ppm siarki, o temperaturze 200-220C. Wykazano, że cementyt na powierzchni i we wnętrzu stali ulega przemianie w niestabilną, quasi-krystaliczną fazę wzbogaconą w siarkę i pierwiastki domieszkowe a zubożoną w żelazo. Przemiana cementytu i rozpad zdegradowanej fazy związana jest z uwolnieniem...
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Zmiany zasolenia na ujęciu ''Czarny Dwór'' w świetle eksploatacji czwartorzędowego poziomu wodonośnego
PublikacjaW wyniku intensywnej eksploatacji ujęcia ''Czarny Dwór'' nastąpił wzrost stężenia chlorków w latach 80-tych i 90-tych, będący efektem intruzji wód morskich. Obecnie obserwuje się znaczny spadek ich koncentracji i cofanie się frontu zasolonych wód z warstwy wodonośnej.
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Process zone in the Single Cantilever Beam under transverse loading. - Part I: Theoretical analysis
PublikacjaSingle Cantilever Beam (SCB) specimen loaded with a transverse force parallel to the crack front is proposed for the analysis of crack propagation phenomena under mixed mode conditions. The stress redistribution in the adhesive layer in the vicinity of the crack front so as the beam deformation are estimated using a Timoshenko beam on elastic foundation model. This model emphasizes the Mode II contribution due to flexural beam...
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Próby mechaniki pękania asymetrycznych złączy klejonych
PublikacjaPraca dotyczy badań asymetrycznych złączy klejonych. Technika połączeń adhezyjnych jest obecnie szeroko stosowana w transporcie, szczególnie lotniczym ale również w budownictwie czy medycynie. W większość zastosowań praktycznych za pomocą klejenia łączy się różne materiał, jednak dla tego typu złączy nie ma żadnych norm czy wytycznych przeprowadzania prób. W pracy zaproponowano trzy metody badania złączy asymetrycznych. Dodatkowo...
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An evaluation and explanation of (in)efficiency in higher education institutions in Europe and the U.S. with the application of two-stage semi-parametric DEA
PublikacjaThis study uses data envelopment analysis (DEA) to evaluate the relative efficiency of 500 higher education institutions (HEIs) in ten European countries and the U.S. for the period between 2000 and 2010. Efficiency scores are determined using different input-output sets (inputs: total revenue, academic staff, administration staff, total number of students; outputs: total number of publications, number of scientific articles, graduates)...
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Expedited constrained multi-objective aerodynamic shape optimization by means of physics-based surrogates
PublikacjaIn the paper, computationally efficient constrained multi-objective design optimization of transonic airfoil profiles is considered. Our methodology focuses on fixed-lift design aimed at finding the best possible trade-offs between the two objectives: minimization of the drag coefficient and maximization of the pitching moment. The algorithm presented here exploits the surrogate-based optimization principle, variable-fidelity computational...
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Grid Implementation of a Parallel Multiobjective Genetic Algorithm for Optimized Allocation of Chlorination Stations in Drinking Water Distribution Systems: Chojnice Case Study
PublikacjaSolving multiobjective optimization problems requires suitable algorithms to find a satisfactory approximation of a globally optimal Pareto front. Furthermore, it is a computationally demanding task. In this paper, the grid implementation of a distributed multiobjective genetic algorithm is presented. The distributed version of the algorithm is based on the island algorithm with forgetting island elitism used instead of a genetic...
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On deterministic procedures for low-cost multi-objective design optimization of miniaturized impedance matching transformers
PublikacjaPurpose This paper aims to investigate deterministic strategies for low-cost multi-objective design optimization of compact microwave structures, specifically, impedance matching transformers. The considered methods involve surrogate modeling techniques and variable-fidelity electromagnetic (EM) simulations. In contrary to majority of conventional approaches, they do not rely on population-based metaheuristics, which permit lowering...
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SAMOCHÓD SPORTOWY DUOMOTO NAPĘDZANY DWOMA SILNIKAMI SPALINOWYMI
PublikacjaPrzedstawiono zaprojektowany i zbudowany przez zespół czterech dyplomantów Wydziału Mechanicznego Politechniki Gdańskiej samochód sportowy napędzany dwoma silnikami. Jeden z nich umieszczono z przodu pojazdu. Przekazuje on moment obrotowy na koła osi przedniej poprzez zespolony układ napędowy. Drugi silnik, usytuowany ztyłu pojazdu, w identyczny sposób przekazuje moment napędowy na koła osi tylnej....
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Thermal Self-Action Effects of Acoustic Beam in a Gas with Reversible or Irreversible Chemical Reaction
PublikacjaThermal self-action of acoustic beam in a gas where an exothermic chemical reaction takes place, is studied. This kind of thermal self-action differs from that in a newtonian fluid. In dependence on the type of a chemical reaction, reversible or not, heating or cooling of a medium occurs. A beam in the case of the irreversible reaction may be unusually self-focusing. The self-action effects relating to wave beams containing shock...
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Fracture in composite/aluminium joints of variable adhesive properties
PublikacjaA strain gauge technique recently developed with the wedge test, for estimating crack length and, thus, the fracture energy of structural adhesive bonding, has been employed on a system in which one adherend had two types of surface treatment. Simple polishing and polishing with subsequent sandblasting were the treatments used, with a distinct straight line, perpendicular to the sample edges, separating the two. Despite the clear-cut...
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Jumping Wave Characteristic during Low Plasticity Burnishing Process
PublikacjaDuring the low plasticity burnishing process of soft materials such as carbon steel with a hardness of up to 40 HRC (Rockwell grade) a raised structure of the material known as the Jumping Wave forms in front of the tool roll. This phenomenon significantly disturbs the burnishing process, but is very poorly described in the literature. This article presents studies of this phenomenon on the example of burnished 1.0562 steel. The...
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Multiobjective Aerodynamic Optimization by Variable-Fidelity Models and Response Surface Surrogates
PublikacjaA computationally efficient procedure for multiobjective design optimization with variable-fidelity models and response surface surrogates is presented. The proposed approach uses the multiobjective evolutionary algorithm that works with a fast surrogate model, obtained with kriging interpolation of the low-fidelity model data enhanced by space-mapping correction exploiting a few high-fidelity training points. The initial Pareto...
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Transformation of the Odesa Waterfront
PublikacjaOdesa is a unique city: it is the third-largest city in Ukraine and the second in the Black sea region. During its short but eventful history, it gathered a variety of cultural layers within its boundaries, what had reflected in its architecture, urban life, and unique accent of its inhabitants. The city`s waterfront is considered to be the Pearl of the Black Sea. Starting with the receiving of the Porto Franco status in 1819,...