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Search results for: RESIDUAL STRESS FATIGUE LIFE MULTI-PASS WELD BISALLOY 80 STRAIN GAUGE
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Scalability of surrogate-assisted multi-objective optimization of antenna structures exploiting variable-fidelity electromagnetic simulation models
PublicationMulti-objective optimization of antenna structures is a challenging task due to high-computational cost of evaluating the design objectives as well as large number of adjustable parameters. Design speedup can be achieved by means of surrogate-based optimization techniques. In particular, a combination of variable-fidelity electromagnetic (EM) simulations, design space reduction techniques, response surface approximation (RSA) models,...
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A multi-criteria decision model for the introduction of electric storage multiple units on the partially electrified Gdynia-Hel railway
Publication: In this article a multi-criteria study of the use of independently powered electric multiple units on the partially electrified Gdynia Główna - Hel line was carried out. The use of (currently used) diesel and, as an alternative, electric and electric multiple units with an electric energy storage was considered. The analysis was carried out on the basis of three criteria for assessing the route service options, i.e. environmental,...
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Multi-Criterial Design of Antennas with Tolerance Analysis Using Response-Feature Predictors
PublicationImperfect manufacturing is one of the factors affecting the performance of antenna systems. It is particularly important when design specifications are strict and leave a minimum leeway for a degradation caused by geometry or material parameter deviations from their nominal values. At the same time, conventional antenna design procedures routinely neglect to take the fabrication tolerances into account, which is mainly a result...
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Hybrid Multi-Criteria Method of Analyzing the Location of Distributed Renewable Energy Sources
PublicationThis paper presents the development and the application of a hybrid multi-criteria method, the combination of the Analytic Hierarchy Process (AHP), and numerical taxonomy (NT),to support the decision making on the location of distributed renewable energy sources meetingvarious types of assessment criteria. Finding criteria weights, using the AHP method, eliminates thedisadvantage of NT—which, in current form, is defined by its...
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Generalized Pareto ranking bisection for computationally feasible multi-objective antenna optimization
PublicationMulti-objective optimization (MO) allows for obtaining comprehensive information about possible design trade-offs of a given antenna structure. Yet, executing MO using the most popular class of techniques, population-based metaheuristics, may be computationally prohibitive when full-wave EM analysis is utilized for antenna evaluation. In this work, a low-cost and fully deterministic MO methodology is introduced. The proposed generalized...
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Experimental investigation of thermal energy storage in shell-and-multi-tube unit with nano-enhanced phase change material
PublicationThis paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled...
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Influence of burnishing on stress corrosion cracking susceptibility of duplex steel
PublicationNa próbkach ze stali duplex poddanych procesom nagniatania przeprowadzono badania podatności do naprężeniowego pękania korozyjnego. Przeprowadzono testy odkształcania z małą prędkością w środowisku wrzącego 35% MgCl2 i środowisku obojętnym- glicerynie. Stwierdzono zwiększoną odporność korozyjną stali po procesach nagniatania z niewielkim stopniem zgniotu. Stwierdzono, że zgniot powierzchniowy ma wpływ na przebieg procesu korozyjnego...
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Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities
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Obesity-related hypertension: relevance of vascular responses to mental stress
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Oxidatively Damaged DNA/Oxidative Stress in Children with Celiac Disease
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Does morphology of carotid plaque depend on patient's oxidative stress?
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The influence of air humidity on human heat stress in a hot environment
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SIMPLIFIED MODELING OF STRESS AND DEFLECTION LIMIT STATES OF UNDERGROUND TANKS
PublicationFuel tanks are designed with regard to standard actions and operating conditions. The work analyses the impact of corrosion and other means to variation of stresses and deformation of a horizontal underground tank shell. The computations are preliminary. Due to the long computational time of the entire tank the analysis is restricted to its part only. The full analysis is bound to assess structural reliability, further allowing...
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When technology use causes stress: Challenges for contemporary research
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How to Create Healthy, Stress-Resilient Post-Pandemic Cities
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Sex differences in oxidative stress after eccentric and concentric exercise
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Cyclic mechanical stress impact on protective properties of organic coatings
PublicationCelem pracy jest zaprezentowanie wyników badań wpływu cyklicznych naprężeń mechanicznych na układy powłoka/metal. Powtarzające się naprężenia mechaniczne zostały zidentyfikowane jako czynnik w znaczącym stopniu przyczyniający się do degradacji powłok. Próbki składające się z powłoki epoksydowej nałożonej na stal St3SAl poddano serii 21000 cykli naprężenie-odpuszczenie. Badania przeprowadzono w zakresie odkształceń elastycznych...
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Pitting corrosion and stress-corrosion cracking of buffer tanks in a brewery
PublicationW pracy przedstawiono wyniki ekspertyzy zbiornika magazynowego na ciepłą wodę do produkcji piwa w browarze. Zbiornik uległ przyśpieszonym procesom korozyjnym, które doprowadziły do jego perforacji. Podczas eksploatacji zbiornika wystąpił proces korozji wżerowej oraz pękania korozyjnego. Przyśpieszone procesy korozyjne zbiornika związane były z wysoką zawartością jonów chlorkowych w wodzie oraz statycznymi naprężeniami mechanicznymi....
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EFFECT OF SURFACE STATE AND STRESS ON AN OXIDATION OF THE ZIRCALOY-2 ALLOY
PublicationZr alloys are widely used as materials for nuclear fuel pellets in the nuclear industry. In the case of the LOCA or RIA happen, a temperature may locally reach high values. Even if the high temperature maintains shortly, the zirconium oxides may become permeable, absorb hydrogen appearing in cooling water from decomposition reaction and crack because of formation and brittle failure of hydrides. Such model cannot so far take into...
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Mechanical properties of the human stomach under uniaxial stress action
PublicationThe aim of this study was to estimate the range of mechanical properties of the human stomach in order to use the collected data in numerical modelling of surgical stapling during resections of the stomach. The biomedical tests were conducted in a self-developed tensile test machine. Twenty-two fresh human stomach specimens were used for the experimental study of its general strength. The specimens were obtained from morbidly obese...
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Degradation of organic coatings subjected to alternating mechanical stress impact.
PublicationW pracy przedstawiono wyniki badań nad wpływem cyklicznych naprężeń mechanicznych na dwa rodzaje systemów powłokowych stosowanych do ochrony konstrukcji mostowych. Powłoki epoksydowe i winylowe poddano cyklom zginanie/odpuszczenie w granicach odkształceń elastycznych materiału podłoża. Stan powłok oceniano przy użyciu techniki elektrochemicznej spektroskopii impedancyjnej. Otrzymane wyniki porównano z zachowaniem analogicznych...
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Applications of electrochemical noise technique in stress corrosion cracking diagnosis
PublicationW pracy przedstawione zostały rezultaty analizy prądowego szumu elektrochemicznego, generowanego podczas korozji naprężeniowej próbek stali stopowej. W przeciwieństwie do tradycyjnych metod analizy nie zakładano stacjonarności analizowanych sygnałów. Zamiast tego analizie poddana została zmodyfikowana widmowa odpowiedź szumowa o charakterze zależnym od czasu. Rezultaty badań skonfrontowano z wynikami otrzymanymi za pomocą techniki...
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Influence of stress on oxidation behaviour of carbon steel studded coil.
PublicationAnalizowano awarię wężownicy kołkowej ze stali węglowej pracującej przez 10 lat w środowisku przegrzanej pary w temperaturze 290ºC i ciśnieniu 0,67 MPa. Obserwacje mikroskopowe powierzchni i przekroju rury ukazały drobne pęknięcia w ściance wynikające z procesu selektywnego utleniania. Zastosowano metodę elementów skończonych w celu ustalenia zależności postępu korozji od ciśnienia i obciążenia cieplnego.
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Accelerated degradation of organic coatings due to cyclic mechanical stress
PublicationPotrzeba okresowej renowacji wymalowań na obiektach technicznych wynika z naturalnej degradacji powłok ochronnych wskutek oddziaływania czynników obecnych w miejscu eksploatacji. W niniejszej pracy opisano synergiczny wpływ dwóch z nich - promieniowana ultrafioletowego i cyklicznych naprężeń mechanicznych - na trwałość komercyjnie stosowanego zestawu powłokowego przeznaczonego do ochrony konstrukcji mostowych.
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Multi-objective Tabu-based Differential Evolution for Teleportation of Smart Virtual Machines in Private Computing Clouds
PublicationWe propose a multi-objective approach for using differential evolution algorithm with tabu search algorithm as an additional mutation for live migration (teleportation) of virtual machines. This issue is crucial in private computing clouds. Teleportation of virtual machines is supposed to be planned to determine Pareto-optimal solutions for several criteria such as workload of the bottleneck host, communication capacity of the...
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Machine Learning Assisted Interactive Multi-objectives Optimization Framework: A Proposed Formulation and Method for Overtime Planning in Software Development Projects
PublicationMachine Learning Assisted Interactive Multi-objectives Optimization Framework: A Proposed Formulation and Method for Overtime Planning in Software Development Projects Hammed A. Mojeed & Rafal Szlapczynski Conference paper First Online: 14 September 2023 161 Accesses Part of the Lecture Notes in Computer Science book series (LNAI,volume 14125) Abstract Software development project requires proper planning to mitigate risk and...
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Radosław Szmytkowski prof. dr hab.
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Fast Multi-Objective Antenna Optimization Using Sequential Patching and Variable-Fidelity EM Models
PublicationIn this work, a technique for fast multi-objective design optimization of antenna structures is presented. In our approach, the initial approximation of the Pareto set representing the best possible trade-offs between conflicting design objectives is obtained by means of sequential patching of the design space. The latter is a stencil-based search that aims at creating a path that connects the extreme Pareto-optimal designs (obtained...
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Study of the Effectiveness of Model Order Reduction Algorithms in the Finite Element Method Analysis of Multi-port Microwave Structures
PublicationThe purpose of this paper is to investigate the effectiveness of model order reduction algorithms in finite element method analysis of multi-port microwave structures. Consideration is given to state of the art algorithms, i.e. compact reduced-basis method (CRBM), second-order Arnoldi method for passive-order reduction (SAPOR), reduced-basis methods (RBM) and subspace-splitting moment-matching MOR (SSMM-MOR)
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A fast time-frequency multi-window analysis using a tuning directional kernel
PublicationIn this paper, a novel approach for time-frequency analysis and detection, based on the chirplet transform and dedicated to non-stationary as well as multi-component signals, is presented. Its main purpose is the estimation of spectral energy, instantaneous frequency (IF), spectral delay (SD), and chirp rate (CR) with a high time-frequency resolution (separation ability) achieved by adaptive fitting of the transform kernel. We...
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Modified Preisach model of hysteresis in multi air gap ferrite core medium frequency transformer
PublicationThis article presents the modified Preisach model of hysteresis for a 3-phase medium frequency transformer in a 100 kW dual active bridge converter. The transformer magnetic core is assembled out of ferrite I-cores, which results in multiple parasitic air gaps. For this transformer, the hysteresis loops were measured and parameters of the Preisach model were determined. The Preisach distribution function is approximated with a...
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Multi-sensor monitoring of the corrosion rate and the assessment of the efficiency of a corrosion inhibitor in utility water installations
PublicationThis paper presents an implementation of the monitoring of the corrosion rate and the assessment of the efficiency of a corrosion inhibitor in a utility water installation using an automated corrosion monitoring system. Due to the fact that the corrosion inhibitor was added to water intended for human consumption, it was necessary to build a multi-sensor monitoring system. In order to implement corrosion monitoring using a linear...
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Self-Organization in Multi-Agent Systems Based on Examples of Modeling Economic Relationships between Agents
PublicationThe goal of the research was to observe and analyze self-organization patterns in Multi-Agent Systems (MAS) by modeling basic economic relationships between agents forming a closed loop of relations necessary for their survival. The paper describes a worked-out MAS including an example of a production cycle and used economic rules. A special focus is put on behavior rules and decision systems of an individual agent such as: product...
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Overcoming “Big Data” Barriers in Machine Learning Techniques for the Real-Life Applications
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Self-Concept Clarity and Religious Orientations: Prediction of Purpose in Life and Self-Esteem
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Wind and Solar Power Plant End-of-Life Equipment: Prospects for Management in Ukraine
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Limiting futile therapy as part of end-of-life care in intensive care units
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Mental state and quality of life after 10 session whole-body cryotherapy
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Importance of Illness Acceptance Among Other Factors Affecting Quality of Life in Acromegaly
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LIFE-SAVING PROCEDURES AND CARDIOPULMONARY RESUSCITATION FROM THE ANCIENT HISTORY TO THE PRESENT DAY
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Life style and cardiovascular risk factors among students of Wroclaw postgraduate schools
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Life Cycle Cost Assessment and the Optimum Design of Timber Roofs for Sustainable Construction
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The Relationship of Purpose in Life and Hope in Shaping Happiness Among Patients with Cancer in Poland
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Selected aspects of palliative care and quality of life at the terminal stage of neoplastic disease
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Stiffness assessment of the laminate recovered from end-of-life wind turbine blade
PublicationIn the paper the stiffness parameters of the laminate recovered from an aerodynamic shell of a decommissioned wind turbine blade are evaluated. The aim of the work is to assess selected methods for identifying material data, as well as to estimate the level of stiffness degradation during turbine operation. Several practical identification methods are presented and compared. Two concepts of a single laminate layer are considered,...
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Comparison of Surface Quality and Tool-Life of Glulam Window Elements after Planing
PublicationThe quality of the surface of wooden elements, that have been planed, has a crucial importance in the whole production process, since the obtained effects affect the quality of wooden surface after fi nishing (painting). The occurrence of defects is usually the reason for qualifying a workpiece as scrap or for requiring additional work. This paper presents the selected results of research of the effect of the cutting tool wear...
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
PublicationThe paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization...
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Estimating of the rough green target size in lumber manufacturing on the twin shaft multi-rip saws
PublicationW pracy przedstawiono analizę i wyniki badań doświadczalnych dokładności przecinania pryzm ze zmrożonego drewna brzozowego na dwuwrzecionowej pilarce tarczowej w warunkach przemysłowych. W badaniach wykorzystywano piły typu "Multix" oraz piły nowego typu. Ponadto, wykazano, że obecność w przekroju poprzecznym, zmiennego na długości przecinanej deski, stopnia po obu jej stronach ma znaczny wpływ na szacowanie wymiaru początkowego...
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Improving evolutionary multi-objective optimisation by niching
PublicationW pracy rozważa się ogólny problem optymalizacji ewolucyjnej i przestrzeniach wielowymiarowych, ze szczególnym uwzględnieniem mechanizmu niszowania, biorącego pod uwagę oceniane charakterystyki (funkcje przystosowania) osobników w generowanych nowych pokoleniach. Mechanizm ten służy do zapobiegania przedwczesnej zbieżności procedur ewolucyjnych poszukiwań oraz zwiększenia efektywności poszukiwań rozwiązań optymalnych. Polega on...
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Multi-armed jets: A subset of the blooming jets
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