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Search results for: LOW-FIDELITY MODELS
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Reliability of imperfect structures (simple non-linear models)
PublicationPrzyjęto proste modele prętów umożliwiających analizę układów o niestatecznych i statecznych punktach bifurkacji. Wykorzystano symulacyjną metodę wyznaczania niezawodności. Zastosowano metodę Monte Carlo i równania 3 poziomu dokładności. Uzyskano rozkłady prawdopodobieństwa obciążenia granicznego nieliniowych modeli konstrukcji z losowymi imperfekcjami. Wykazano, że histogramy siły granicznej modelu statecznego i niestatecznego...
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Experimental measurements of the hydrodynamic characteristics of the pod propulsor models
PublicationPraca przedstawia wyniki pomiarów charakterystyk hydrodymicznych trzech wariantów modelu pędnika azymutalnego. Charakterystyki obejmują napór pędnika, siłę boczną i moment względem osi pionowej w zależności od współczynnika posuwu i kąta dryfu.
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Case Study NEB Atlas / part I - 3D Models / Brunnshög, Lund
Open Research DataThe data presents the results of work on the analysis of contemporary neighbourhoods. The aim of this part of the research was to create a digital model - a simplified digital twin - for selected parts of housing estates already realised in various cities in Europe. This group presents a model for a fragment of the Brunnshög district in Lund, Sweden....
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CONSTRUCTION TECHNOLOGY OF TIMBER-FRAME HOUSES RESISTANT TO DYNAMIC LOADS – STUDY ON MODELS OF EXTERIOR WALLS
PublicationThe aim of this paper is to show the numeric representation of experimental studies concerning the behaviour of exterior wall models of a timber-frame house under harmonic loading. A single wall model according to traditional technology of timberframe house walls (filling with mineral wool) was tested. The analysis was conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified...
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Recent advances in traffic optimisation: systematic literature review of modern models, methods and algorithms
PublicationOver the past few decades, the increasing number of vehicles and imperfect road traffic management have been sources of congestion in cities and reasons for deteriorating health of its inhabitants. With the help of computer simulations, transport engineers optimise and improve the capacity of city streets. However, with an enormous number of possible simulation types, it is difficult to grasp valuable, innovative solutions which...
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Low-Cost and Highly-Accurate Behavioral Modeling of Antenna Structures by Means of Knowledge-Based Domain-Constrained Deep Learning Surrogates
PublicationThe awareness and practical benefits of behavioral modeling methods have been steadily growing in the antenna engineering community over the last decade or so. Undoubtedly, the most important advantage thereof is a possibility of a dramatic reduction of computational expenses associated with computer-aided design procedures, especially those relying on full-wave electromagnetic (EM) simulations. In particular, the employment of...
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Tilting pad thrust bearing with novel material selection - experimental comparison of low and medium speed operation
PublicationThe advances in material engineering led to the development of hard carbon based coatings applied in numerous applications in order to prevent or minimize wear of the parts in contact. With Triondur® coatings, the bearing company Schaeffler has succeeded in halving the friction losses in the valve trains of passenger cars. The coatings are optimized for high abrasive wear protection and low sliding friction moments. Altogether...
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Novel topology of compact coplanar waveguide resonant cell low-pass filter
PublicationIn 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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The Dilemmas of Choosing a Suitable Technology for Low Energy and Passive Houses in the Context of their Overheating Issues
PublicationIn compliance with European Union directives, numerous countries are introducing increasingly stricter legal limits on the estimated energy consumption of newly designed residential buildings. However, the fact, that regulations and designers' efforts are focused on decreasing energy consumption (and consequently carbon dioxide emissions) only at the post-occupancy stage, may lead to a significant increase in the carbon footprint...
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Optimal Design of Transmitarray Antennas via Low-Cost Surrogate Modelling
PublicationOver the recent years, reflectarrays and transmitarrays have been drawing a considerable attention due to their attractive features, including a possibility of realizing high gain and pencil-like radiation patterns without the employment of complex feeding networks. Among the two, transmitarrays seem to be superior over reflectarrays in terms of achieving high radiation efficiency without the feed blockage. Notwithstanding, the...
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ENERGY AND EMISSION QUALITY RANKING OF NEWLY PRODUCED LOW-SULPHUR MARINE FUEL
PublicationThe article describes the methodology of engine tests on new types of low-sulphur marine fuels in laboratory conditions in order to conduct a comprehensive assessment of their suitability for powering full-size marine engines. The innovativeness of the proposed solution consists of adapting the laboratory Diesel Engine Test Bed to carry out experimental tests using residual and alternative fuels so that it is possible to imitate...
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Assessment of Fuel Cells’ State of Health by Low-Frequency Noise Measurements
PublicationWe proposed applying low-frequency (flicker) noise in proton-exchange membrane fuel cells under selected loads to assess their state of health. The measurement set-up comprised a precise data acquisition board and was able to record the DC voltage and its random component at the output. The set-up estimated the voltage noise power spectral density at frequencies up to a few hundred mHz. We observed the evolution of the electrical...
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Low noise poroelastic road pavements based on modified asphalt binder
PublicationTire/road noise is one of the most important environmental problems related to road traffic. As the most effective way to fight noise is reduction of sound emission from the source, a lot of work is being done to improve tire and road surfaces construction. This paper describes the first “road” results obtained within the SEPOR project, which is focused on developing a low noise poroelastic road surface based on bituminous binder....
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Impact of Low Switching-to-Fundamental Frequency Ratio on Predictive Current Control of PMSM: A simulation study
PublicationPredictive current control algorithms for permanent magnet synchronous (PMSM) drives rely on an assumption that within short intervals motor currents can be approximated with linear functions. This approximation may result either from discretizing the motor model or from simplifications applied to the continuous-time model. As the linear current approximation has been recognized as inaccurate in case when the drive operates with...
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublicationConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
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Inverse and forward surrogate models for expedited design optimization of unequal-power-split patch couplers
PublicationIn the paper, a procedure for precise and expedited design optimization of unequal power split patchcouplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to thecircuit operating at the requested frequency and featuring a required power split. At the same time, thedesign process is supposed to be computationally efficient. The proposed methodology involves two typesof auxiliary models (surrogates):...
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Field Calibration of Low-Cost Particulate Matter Sensors Using Artificial Neural Networks and Affine Response Correction
PublicationDue to detrimental effects of atmospheric particulate matter (PM), its accurate monitoring is of paramount importance, especially in densely populated urban areas. However, precise measurement of PM levels requires expensive and sophisticated equipment. Although low-cost alternatives are gaining popularity, their reliability is questionable, attributed to sensitivity to environmental conditions, inherent instability, and manufacturing...
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Synthetic strategies in construction of organic low molecular-weight carrier-drug conjugates
PublicationInefficient transportation of polar metabolic inhibitors through cell membranes of eukaryotic and prokaryotic cells precludes their direct use as drug candidates in chemotherapy. One of the possible solutions to this problem is application of the ‘Trojan horse’ strategy, i.e. conjugation of an active substance with a molecular carrier of organic or inorganic nature, facilitating membrane penetration. In this work, the synthetic...
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Low-Cost Data-Driven Surrogate Modeling of Antenna Structures by Constrained Sampling
PublicationFull-wave electromagnetic (EM) analysis has become one of the major design tools for contemporary antenna structures. Although reliable, it is computationally expensive which makes automated simulation-driven antenna design (e.g., parametric optimization) difficult. This difficulty can be alleviated by utilization of fast and accurate replacement models (surrogates). Unfortunately, conventional data-driven modeling of antennas...
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Accuracy of a low-cost autonomous hexacopter platforms navigation module for a photogrammetric and environmental measurements
PublicationA photogrammetry and environmental measurements from an unmanned aerial vehicle (UAV) are a low-cost alternative for a traditional aerial photogrammetry. A commercial off-the-shelf products (COTS) offers a variety of cheap components that a suitable to be used on board a UAV. In this paper a low-cost navigation module based on Ublox NEO-M8N GPS and Pixhawk flight controller have been described, as a main extrinsic parameters source...
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Investigations of the Working Process in a Dual-Fuel Low-Emission Combustion Chamber for an FPSO Gas Turbine Engine
PublicationThis investigation is devoted to an analysis of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. The low-emission gas turbine combustion chamber with partial pre-mixing of fuel and air inside the outer and inner radial-axial swirlers was chosen as the object of research. When modelling processes in a dual-flow low-emission gas turbine combustion chamber, a generalized method...
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Design and Analysis of Artificial Neural Network (ANN) Models for Achieving Self-Sustainability in Sanitation
PublicationThe present study investigates the potential of using fecal ash as an adsorbent and demonstrates a self-sustaining, optimized approach for urea recovery from wastewater streams. Fecal ash was prepared by heating synthetic feces to 500 °C and then processing it as an adsorbent for urea adsorption from synthetic urine. Since this adsorption approach based on fecal ash is a promising alternative for wastewater treatment, it increases...
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Werkwinkel: Journal of Low Countries and South African Studies
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The Low Countries: Arts and Society in Flanders and the Netherlands. A Yearbook
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Towards Designing an Innovative Industrial Fan: Developing Regression and Neural Models Based on Remote Mass Measurements
PublicationThis article presents the process of the construction and testing a remote, fully autonomous system for measuring the operational parameters of fans. The measurement results obtained made it possible to create and verify mathematical models using linear regression and neural networks. The process was implemented as part of the first stage of an innovative project. The article presents detailed steps of constructing a system to...
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A new method of fault loop resistance measurement in low voltage systems with residual current devices
PublicationThis paper presents a new method of fault loop resistance measurement in low voltage systems with residual current devices. The method enables measuring fault loop resistance without nuisance tripping of residual current devices, by application an unconventional waveform of measurement current. It is important for proper verification of the effectiveness of protection against electric shock.
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Total cross section for low-energy electron scattering from formic acid, (HCOOH), molecules
PublicationTotal cross section (TCS) for low-energy electron scattering from formic acid molecules has been measured using electrostatic electron spectrometer working in linear transmission mode. Two local maxima centered around 1.7 eV and 7.8 eV have been observed and associated with resonant scattering processes.
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GIS Technology, 3D Models and Mathematical Models as a Tool for Assessing Development Capabilities of Flood Risk Land to Make Arrangements of Municipal Planning Documents
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Miniaturization of ESPAR Antenna Using Low-Cost 3D Printing Process
PublicationIn this paper, the miniaturized electronically steerable parasitic array radiator (ESPAR) antenna is presented. The size reduction was obtained by embedding its active and passive elements in polylactic acid (PLA) plastic material commonly used in low-cost 3D printing. The influence of 3D printing process imperfections on the ESPAR antenna design is investigated and a simple yet effective method to...
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Low to intermediate energy elastic electron scattering from dichloromethane (CH2Cl2)
PublicationWe report a theoretical-experimental investigation of electron scattering by dichloromethane (CH2Cl2) in the low- and intermediate energy ranges. Experimental elastic differential cross sections (DCS), in the incident electron energy range of 0.5-800 eV and scattering angle range of 10°–130°, were measured using a crossed beam relative flow technique. Integral and momentum- transfer cross sections were determined from the experimental...
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USEFULNESS OF SEMI-MARKOV PROCESSES AS MODELS OF THE OPERATION PROCESSES FOR MARINE MAIN ENGINES AND OTHER MACHINES OF SHIP POWER PLANTS
PublicationThe paper describes the properties of semi-Markov processes and the opportunities and benefits from their use as models of the operation processes for marine combustion engines and other machines of ship power plants. The emphasis is put on the importance of the theory of semi-Markov processes for development of the theory of marine combustion engines and other machines of ship power plants, as well as for development of the operational...
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Methods of deep modification of low-bearing soil for the foundation of new and spare air runways
PublicationAfter analyzing the impact of aircraft on the airport pavement (parking spaces, runways, startways), it was considered advisable to consider the problem of deep improvement or strengthening of its subsoil. This is especially true for low-bearing soil. The paper presents a quick and effective method of strengthening the subsoil intended for the construction of engineering structures used for civil...
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Prototype of a low-cost luxmeter with wide measuring range designed for railway stations dynamic lighting systems
PublicationThe paper presents the development of a low-cost luxmeter designed for usage in automatic applications for continual (long-term) measurement of illuminance. The measured information is used to adjust the level of lighting systems of artificial lighting on railways (platforms, marshalling yard, tracks etc.). The reason of this measuring device is a requirement for massive deployment of dimmable lighting systems for railways, in...
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Flow Maps and Flow Patterns of R1233zd(E) in a Circular Minichannel at Low, Medium and High Values of Saturation Pressure
PublicationThere is a gap in knowledge regarding the flow pattern of low-boiling working fluids in the range of high saturation temperatures (above 120°C) and medium and high reduced pressures (0.5-0.9). Data are present in the literature for similar values of reduced pressures, but for lower values of saturation temperature. This is due to the existing refrigeration applications of these working fluids. At high values of reduced pressure,...
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PROBLEMS OF THE STARTING AND OPERATING OF HYDRAULIC COMPONENTS AND SYSTEMS IN LOW AMBIENT TEMPERATURE (PART V) METHODS ENSURING CORRECT START-UP OF HYDRAULIC COMPONENTS OF SHIP’S ONBOARD DEVICES IN LOW AMBIENT TEMPERATURES
PublicationA large number of hydraulic devices and systems are started in low ambient temperatures. A good example of such a device is the hoisting winch on the ship. Starting hydraulic drive units in thermal shock conditions (rapid supply of hot oil to the cold unit) may lead to incorrect operation of the actuating system, for instance, due to the loss of clearance between cooperating elements. The article presents methods to prevent the...
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STILL ‘FEW, SLOW AND LOW’? ON THE FEMALE DIMENSION OF TECHNOLOGY, LABOUR MARKETS AND ECONOMIC ACTIVITY: EVIDENCE FOR THE PERIOD OF 1990-2017
PublicationThe known in empirical economics question ‘Why so Few? Why so Slow? Why so Low?’ refers here to the persistently small number of women involved in innovative activities, the slowness of change in the inequalities between women and men in these fields, and women’s continuing lower rank in business and academic positions. In developing countries, women`s labour and entrepreneurial activity remains an ‘untapped resource’ for economic...
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Corrosion and Cavitation Resistances of Low Alloy Steel After Frictional-Mechanical Treatment
PublicationPaper presents the results of the studies of wear, corrosion and cavitation resistances of the S355J2 low alloy medium carbon steel subjected to surface modification by friction-mechanical treatment, as tested in sea water simulated solution. To evaluate the effect of the surface treatment, the comparative studies of the corrosive properties of the steel before and after treatment have been considered. The treatment due to a severe...
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
PublicationHot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point...
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Neural network based algorithm for hand gesture detection in a low-cost microprocessor applications
PublicationIn this paper the simple architecture of neural network for hand gesture classification was presented. The network classifies the previously calculated parameters of EMG signals. The main goal of this project was to develop simple solution that is not computationally complex and can be implemented on microprocessors in low-cost 3D printed prosthetic arms. As the part of conducted research the data set EMG signals corresponding...
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Measurement of selected characteristics of low-coherence optical signal sources for optical coherence tomography
PublicationOCT to nowa metoda badania wewnętrznych struktur materiałów. Wśród wielu technik detekcji sygnału optycznego wykorzystywanych w OCT najpopularniejszą i najbardziej obiecującą jest OLCR (Opticla-Low Coherence Reflectomerty - reflektometria niskokoherentna). OLCR wykorzystuje szerokopasmowe źródła, których parametry, jak np.: charakterystyka widmowa, charakterystyka szumowa, determinują właściwości metrologiczne systemu OCT. W artykule...
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Tailoring a low-energy ball milled MnCo2O4 spinel catalyst to boost oxygen evolution reaction performance
PublicationThe development of cost-efficient oxygen evolution reaction (OER) catalysts is one of the most important tasks facing modern techniques for hydrogen production. In this work, for the first time, a low-energy ball milling process of MnCo2O4 (MCO) spinel powders, with a mechanical modification time exceeding 1 day was used. After 6 days of ball-milling, the obtained overpotential of the electrocatalyst reached the value of 375 mV...
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Two-Rate Based Low-Complexity Variable Fractional-Delay FIR Filter Structures
PublicationThis paper considers two-rate based structures for variable fractional-delay (VFD) finite-length impulse response (FIR) filters. They are single-rate structures but derived through a two-rate approach. The basic structure considered hitherto utilizes a regular half-band (HB) linear-phase filter and the Farrow structure with linear-phase subfilters. Especially for wide-band specifications, this structure is computationally efficient...
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Case Study NEB Atlas / part I - 3D Models / King's Cross, London
Open Research DataThe data presents the results of work on the analysis of contemporary neighbourhoods. The aim of this part of the research was to create a digital model - a simplified digital twin - for selected parts of housing estates already realised in various cities in Europe. This group presents a model for a fragment of the King's Cross, London, UK. The students...
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Uniform sampling in constrained domains for low-cost surrogate modeling of antenna input characteristics
PublicationIn this letter, a design of experiments technique that permits uniform sampling in constrained domains is proposed. The discussed method is applied to generate training data for construction of fast replacement models (surrogates) of antenna input characteristics. The modeling process is design-oriented with the surrogate domain spanned by a set of reference designs optimized with respect to the performance figures and/or operating...
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Modulation of dielectric properties in low-loss polypropylene-based composites at GHz frequencies: theory and experiment
PublicationPolymer composites with high dielectric constant and low loss tangent are highly regarded as substrates for modern high-speed electronics. In this work, we analyze the high-frequency dielectric properties of two types of composites based on polypropylene infused with high-dielectric-constant microparticles. Two types of fillers are used: commercial ceramics or titanium oxide ( TiO2) with different concentrations. The key observation...
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The effect of sunscreen 4‐methylbenzylidene camphor in different and reproductive models, its bioaccumulation and molecular effects on ligand‐receptor interaction, and protein expression
Publication4-Methylbenzylidene camphor (4-MBC) is a photo-absorbing UV filter prevalently used in cosmetics, which can be absorbed into circulation and cause systemic effects. 4-MBC is continued to be released in the environment despite the growing knowledge about its bioaccumulation and endocrine disrupting effects. Previous reviews have mentioned UV-filter together but this review considers 4-MBC alone, due to its prevalence and concerning...
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A Set of Low-power Microcontroller-based Modules Used for Testing of Small Energy Measurement Methods
PublicationEstimation of energy consumption of low-power devices is not widely discussed in the scientific literature, but this topic is getting more and more popular. Evaluation process of newly developed methods and instrumentation requires carefull treatment. In order to fulfill this niche, the set of micro-power microcontroller based devices was proposed. The devices represent typical energy consuption profiles and allow experimental verification...
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Experimental verification of a new method of loop resistance testing in low voltage systems with residual current devices
PublicationA periodical verification of the effectiveness of protection against electric shock shall be performed in low voltage systems. The scope of this verification includes loop impedance/resistance testing. If a residual current device is installed in a tested circuit, this testing is problematic. A residual current device trips out during the test, because of the high value of measurement current. This precludes the execution of the...
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Influence of separation gap on the response of colliding models of steel structures under seismic and paraseismic excitations
PublicationAs a result of high urbanization, the need to erect closely-spaced buildings forces designers to consider collisions between structures taking place during ground motions. Experimental and numerical studies have confirmed that such collisions (often referred to as structural pounding) may cause serious damage to the structural elements and even lead to total collapse of colliding structures. The main reason of earthquake-induced...
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Innovative Urban Blue Space Design in a Changing Climate: Transition Models in the Baltic Sea Region
PublicationWaterfront areas in cities are subject to constant changes. The desire to integrate the transformed waterside areas with the urban fabric involves shaping high-quality public spaces related to water, which are often referred to as urban blue spaces (UBS). The aim of the research was to examine the transformation processes of urban waterfront areas in the Baltic Sea Region and identify emerging transition models and types of blue...