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Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering.
PublicationIron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5~Pa, 1.5~Pa, and 5.0~Pa). The HiPIMS system was operated at a repetition frequency $f = 100$~Hz with a duty cycle of 1~\%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma...
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Buried Object Characterization Using Ground Penetrating Radar Assisted by Data-Driven Surrogate-Models
PublicationThis work addresses artificial-intelligence-based buried object characterization using 3-D full-wave electromagnetic simulations of a ground penetrating radar (GPR). The task is to characterize cylindrical shape, perfectly electric conductor (PEC) object buried in various dispersive soil media, and in different positions. The main contributions of this work are (i) development of a fast and accurate data driven surrogate modeling...
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Novel Cold Crucible Ultrasonic Atomization Powder Production Method for 3D Printing
Publication: A new powder production method has been developed to speed up the search for novel alloys for additive manufacturing. The technique involves an ultrasonically agitated cold crucible installed at the top of a 20 kHz ultrasonic sonotrode. The material is melted with an electric arc and undergoes pulverization with standing wave vibrations. Several different alloys in various forms, including noble and metallic glass alloys, were...
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Signal Propagation in Electromagnetic Media Modelled by the Two-Sided Fractional Derivative
PublicationIn this paper, wave propagation is considered in a medium described by a fractional-order model, which is formulated with the use of the two-sided fractional derivative of Ortigueira and Machado. Although the relation of the derivative to causality is clearly specified in its definition, there is no obvious relation between causality of the derivative and causality of the transfer function induced by this derivative. Hence, causality...
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Simplified approach to assess the dynamic response of a container ship subjected to bow slamming load
PublicationSimplified approach to assess the dynamic response of a container ship subjected to the bow slamming load, resulting in a transient vibratory response, typically called a 'whip-ping', is presented. The accurate numerical modelling is very complex and involves cou-pling of the hydrodynamic and structural solution at every time step, leading to huge com-putational and workload cost. Thus, the one-way coupling methodology is adopted,...
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The electrochemical determination of isatin at nanocrystalline boron-doped diamond electrodes: stress monitoring of animals
PublicationUltra-thin nanocrystalline boron-doped diamond electrodes (B:NCD) were used for the electrochemical determination of isatin in dog urine samples using cyclic voltammetry and square wave voltammetry in a phosphate buffer saline, pH = 7.2. No additional modification or pretreatment of the electrode surface was required in this approach, being of high importance for the facile detection procedure. The increase of the peak current...
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Price convergence in the EU-an aggregate and disaggregate approach
PublicationThis article examines the price dispersion in the European Union (EU) over 15 years (1990-2005). An extensive overview of the literature offers inconclusive results with the half-lives of price shocks from 2.8 to 282 months. Until now, most of the empirical research has been either micro or macro based. In contrast, we conducted a complex analysis utilizing both aggregate and disaggregate price data. The macro approach is based...
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Discouraging Traffic Remapping Attacks in Local Ad Hoc Networks
PublicationQuality of Service (QoS) is usually provided in ad hoc networks using a class-based approach which, without dedicated security measures in place, paves the way to various abuses by selfish stations. Such actions include traffic remapping attacks (TRAs), which consist in claiming a higher traffic priority, i.e., false designation of the intrinsic traffic class so that it can be mapped onto a higher-priority class. In practice, TRAs...
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The convergence of gender wage differences - myth or fact - multi country multi sector analysis
PublicationThe Becker’s theory of discrimination predicts that in the long run the gender wage differences should disappear. In our empirical analysis we verify the testable implications of this mode considering the hypothesis of gender wage gap convergence. The study takes into account 31 sectors in 13 European countries for the period between 1970 and 2005. We distinguish between wages paid to different groups of workers classified according...
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Share of the wage factor in national income – selected aspects
PublicationThe aim of this study is to examine changes in the share of the wage factor in national income, in selected EU countries against labour productivity and investment rates reflecting changes in capital-labour relations, indicated by researchers as determinants of change of the share of the wage factor in national income. The scope of the study includes a review of literature devoted to the issue of wage factor share in national income...
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Abilities, Motivations, and Opportunities of Furloughed Employees in the Context of Covid-19: Preliminary Evidence From the UK
PublicationThe Covid-19 global pandemic is a crisis like no other, forcing governments to implement prolonged national lockdowns in an effort to limit the spread of the disease. As organizations aim to adapt and remain operational, employers can suspend or reduce work activity for events related to Covid-19 and claim government support to subsidize employee wages. In this way, some employees are placed on furlough (i.e., temporary unemployment)...
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DIGITAL HYDRAULICS CIRCUIT BASED ON PWM FUNCTION FOR CONTROLLING HYDRAULIC ACTUATOR POSITION
PublicationHydraulic systems are used in many different industries, such as multi-source hydrostatic drive systems. In traditional hydraulic systems, a proportional servo valve is used to control the position of hydraulic actuators. The low energy efficiency and high cost of these control valves are two major problems with these systems. Digital hydraulics is one of the most unique ideas on how to solve these problems. Researchers like digital...
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A new dilution-enrichment sample preparation strategy for expanded metabolome monitoring of human breast milk that overcomes the simultaneous presence of low- and high-abundance lipid species
PublicationThe complex nature of human breast milk (HBM) makes samples difficult to analyze, requiring several extraction techniques and analytical platforms to obtain high metabolome coverage. In this work, we combined liquid-liquid extraction (LLE) and solid-phase extraction (SPE) techniques to prepare HBM samples to overcome the challenge of low- and high-abundance lipid species, enabling the semiquantitative analysis of total HBM lipids...
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Techniki zwiększania efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur
PublicationWspółczesna elektronika ze względu na swój szybki rozwój wymaga od nas efektywnego modelowania zjawisk polowych. Celem rozprawy jest zwiększanie efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur oraz jej hybrydyzację z użyciem technik analitycznych. Rozprawa zawiera przegląd stanu wiedzy na temat dostępnych obecnie technik modelowania jak również opis...
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A structure and design optimization of novel compact microscrip dual-band rat-race coupler with enhanced bandwidth
PublicationIn the letter, a topology of a novel compact wideband dual-band rat-race coupler has been presented along with its computationally efficient design optimization procedure. Reduction of the circuit size has been achieved by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased so as to secure sufficient flexibility of the circuit, necessary in...
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FDTD Simulations on Disjoint Domains with the Use of Discrete Green's Function Diakoptics
PublicationA discrete Green's function (DGF) approach to couple disjoint domains in the finite-difference time-domain (FDTD) grid is developed. In this method, total-field/scattered-field (TFSF) FDTD domains are associated with simulated objects whereas the interaction between them is modeled with the use of the DGF propagator. Hence, source and scatterer are simulated in separate domains and updating of vacuum cells, being of little interest,...
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Sea bottom structure investigation by means of acoustic methods
PublicationThe main aim of the paper is the result of experimental investigations of the seabed in the Gulf of Gdańsk arried out using parametric echosounder as a main measuring tool. Examination of the surface's upper layer of the seabed, especially is acoustic properties, reflecting most often transsmision and reflection properties of the incident elastic wave, could be a valuable material for determination of the stratification, and the...
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Low current transformer utilizing Co-based amorphous alloys
PublicationMetal oxide surge arresters have been widely used for protection of power system networks against overvoltages due to atmospheric discharges or malfunction of devices connected to the network. During its operation a surge arrester structure is degradated, what can be observed as an increase of a surge arrester leakage current. Paper presents an implementation of a new, high-permeability, Co64Fe4Ni1Si15B14 amorphous alloy as a current...
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Design considerations for compact microstrip resonant cells dedicated to efficient branch-line miniaturization
PublicationA conventional compact microstrip resonant cell (CMRC)has been thoroughly investigated to enhance its slow-wave properties and subsequently ensure an efficient miniaturization of a microstrip circuit. The geometry of a classic CMRC has been improved in terms of slowwave effect in two progressive steps: (i) a single-element topology has been replaced with a double-element one and (ii) a high-impedance section has been refined by...
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Low Current Transformer Utilizing Co-Based Amorphous Alloys
PublicationMetal oxide surge arresters have been widely used for protection of power system networks against overvoltages due to atmospheric discharges or malfunction of devices connected to the network. During its operation a surge arrester structure is degradated, what can be observed as an increase of a surge arrester leakage current. Paper presents an implementation of a new, high-permeability, Co64Fe4Ni1Si15B14 amorphous alloy as a current...
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Diagnostics of the tram track shape with the use of the global positioning satellite systems (GPS/Glonass) measurements with a 20 Hz frequency sampling
PublicationSatellite geodetic measurements used in the diagnosis of railway tracks require professional receivers and a very high frequency rate of data processing. It stems from a significant speed (10 km/h) kinematic measurements carried out during the passage of a measuring platform. The survey results (positions) of deformed railroad track have waveforms nature requiring additional processing methods and approximations. Due to the announcement...
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Parametrized Local Reduced-Order Models With Compressed Projection Basis for Fast Parameter-Dependent Finite-Element Analysis
PublicationThis paper proposes an automated parametric local model-order reduction scheme for the expedited design of microwave devices using the full-wave finite-element method (FEM). The approach proposed here results in parameterized reduced-order models (ROMs) that account for the geometry and material variation in the selected subregion of the structure. In each subregion, a parameter-dependent projection basis is generated by concatenating...
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Coupled Urban Areas Inundation Model with Interaction Between Storm Water System and Surface Flow - Case Study of Sea Level Impact on Seaside Areas Flooding
PublicationInundations are becoming more frequent than ever. What is connected with increasing area of impervious surface in cities. This makes predicting urban flooding and its scale especially important. At the seaside we observe additional conditions such as sea level that makes accurate numerical modelling of issue even harder. With complex approach to the matter which is simultaneous calculation of storm water conduit flow and overland...
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Expedited Feature-Based Quasi-Global Optimization of Multi-Band Antenna Input Characteristics with Jacobian Variability Tracking
PublicationDesign of modern antennas relies—for reliability reasons—on full-wave electromagnetic simulation tools. In addition, increasingly stringent specifications pertaining to electrical and field performance, growing complexity of antenna topologies, along with the necessity for handling multiple objectives, make numerical optimization of antenna geometry parameters a highly recommended design procedure. Conventional algorithms, particularly...
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Reduced-cost surrogate modelling of compact microwave components by two-level kriging interpolation
PublicationFull-wave electromagnetic (EM) analysis is a versatile tool for evaluating the performance of high-frequency components. Its potential drawback is its high computational cost, inhibiting the execution of EM-driven tasks requiring massive simulations. The applicability of equivalent network models is limited owing to the topological complexity of compact microstrip components because of EM cross-coupling effects. Development of...
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Topological extraordinary optical transmission
PublicationΤhe incumbent technology for bringing light to the nanoscale, the near-field scanning optical microscope, has notoriously small throughput efficiencies of the order of 10^4-10^5 or less. We report on a broadband, topological, unidirectionally guiding structure, not requiring adiabatic tapering and, in principle, enabling near-perfect (∼100%) optical transmission through an unstructured single arbitrarily subdiffraction slit at...
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Do Leonardo da Vinci’s drawings, room acoustics and radio astronomy have anything in common?
PublicationAfter introducing Leonardo da Vinci’s (LdV) predecessors in the field of light propagation research, his drawings on the topic of reflecting light by a spherical mirror are analysed. The discovery of LdV is presented, according to which, at an infinitely distant source of rays, a small fragment of the canopy is enough to generate a focus, while the rest of the mirror forms a caustic for which LdV did not indicate an application....
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Adaptive identification of sparse underwater acoustic channels with a mix of static and time-varying parameters
PublicationWe consider identification of sparse linear systems with a mix of static and time-varying parameters. Such systems are typical in underwater acoustics (UWA), for instance, in applications requiring identi- fication of the acoustic channel, such as UWA communications, navigation and continuous-wave sonar. The recently proposed fast local basis function (fLBF) algorithm provides high performance when identi- fying time-varying systems....
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Fast surrogate-assisted frequency scaling of planar antennas with circular polarisation
PublicationIn this work, the problem of computationally efficient frequency scaling (re-design) of circular polarisation antennas is addressed using surrogate-assisted techniques. The task is challenging and requires the identification of the optimum geometry parameters to enable the operation of the re-designed structure at a selected (required) centre frequency. This involves handling several performance figures such as the antenna gain,...
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A Simple-Topology Compact Broadband Circularly Polarized Antenna With Unidirectional Radiation Pattern
PublicationIn this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide (CPW) feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground...
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Essays on China's international trade - focus on One-Belt One-Road initiative
PublicationThis thesis explores China's international trade from trade, global value chains (GVCs) and export diversity, focusing on the "One-Belt One-Road" (OBOR) initiative proposed at the end of 2013. Specifically, I verify the potential association of OBOR with bilateral imports and exports in the first chapter. Then the relationship between OBOR and GVCs has been explored in Chapter 2. And I have extended the research in GVCs to China's...
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Functionalization of Parylene During Its Chemical Vapor Deposition
PublicationTwo possible mechanisms for the reaction of four halogenated (metha)acrylate-based molecules with Parylene [poly (paraxylylene)] during its chemical vapor deposition were proposed. The chemical reactivity of acrylate double bond with the paraxylylene biradical was calculated for all four (metha)acrylate-based molecules. These calculations allowed the evaluation of the energetically favorable mechanism and indeed a direct correlation...
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Mind the Gender Wage Gap – the Impact of Trade and Competition on Sectoral Wage Difference
PublicationThis article examines differences between women’s and men’s wages in 18 selected OECD countries in the period 1970-2005. The study is based on 12 manufacturing sector- and skill-specific sets of panel data on the gender wage gap. We apply a system GMM estimator to the extended version of the conditional gender wage gap convergence equation, controlling for sector concentration and industry-specific measures of openness using a...
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To Survive in a CBRN Hostile Environment: Application of CAVE Automatic Virtual Environments in First Responder Training
PublicationThis paper is of a conceptual nature and focuses on the use of a specific virtual reality environment in civil-military training. We analyzed the didactic potential of so-called CAVE automatic virtual environments for First Responder training, a type of training that fills the gap between First Aid training and the training received by emergency medical technicians. Since real training involves live drills based on unexpected situations,...
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Distinctive facades of commercial buildings and the quality of public space,
PublicationMutual relations between the retail center and public spaces of the city are varied. They depend on the type and size of the commercial structure. Other ones are for multifunctional shopping centers and other for high streets. In megastores and shopping malls the essential for their functioning is their interior and entrance, which is sometimes the only place of interpenetration of the commercial structure with the surrounding...
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Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces
PublicationPopularity of metasurfaces has been continuously growing due to their attractive properties including the ability to effectively manipulate electromagnetic (EM) waves. Metasurfaces comprise optimized geometries of unit cells arranged as a periodic lattice to obtain a desired EM response. One of their emerging application areas is the stealth technology, in particular, realization of radar cross section (RCS) reduction. Despite...
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Integration Data Model of the Bathymetric Monitoring System for Shallow Waterbodies Using UAV and USV Platforms
PublicationChanges in the seafloor relief are particularly noticeable in shallow waterbodies (at depths up to several metres), where they are of significance for human safety and environmental protection, as well as for which the highest measurement accuracy is required. The aim of this publication is to present the integration data model of the bathymetric monitoring system for shallow waterbodies using Unmanned Aerial Vehicles (UAV) and...
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Geodesy measurement techniques as an enrichment of archaeological research workflow
PublicationUse of geodesy techniques is widespread in different fields of science. Especially in such an emerging and dynamic branch of science as archaeology. Warsaw Institute of Archaeology, conducts many archaeological expeditions, among the others Polish-Georgian archaeological expedition in Gonio, where ancient Roman Bath has been discovered and excavated. Gonio is located in Adjara, Georgia, placed on the Black Sea coast. Fortress...
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Female entrepreneurship in Kazakhstan
PublicationWomen constitute the majority of the Kazakh population and, even though they live almost 10 years longer than men on average, they are far less economically active. Less than half of the female population take up employment. Women’s wages are often as much as 30% lower than men’s. The subjective reasons for undertaking economic activity as mentioned by women included: independence from the husband, low earnings of the husband and...
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Adsorption onto zeolites: molecular perspective
Publication2D minerals are among key elements of advanced systems, but the need for understanding their interactions/reactions with materials and systems in which they are involved necessitates tracking their molecular and atomic monitoring. Zeolitic structures are microporous materials formed in the nature through volcanic activities or synthesis. Because of their outstanding physicochemical properties like cation exchange capacity and excellent...
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublicationIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulationand evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modelingand solution rely on finite element methods and cover the simulation of the structure’s properties along with the influenceof the marine environment – sea currents, wave...
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On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
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An Optimized Ka-Band Low Profile Dual-Polarized Transmitarray Antenna With 2D Beam Switching
PublicationThis article presents an optimized dual-polarized transmitarray antenna (TA) designed for MIMO applications at the Ka-band, capable of switching beams in two directions. The antenna aperture uses a small unit cell with three layers of Taconic RF-35 dielectric substrates, which can be easily fabricated using PCB technology. The unit cell achieved a 360-degree phase shift and a transmission magnitude exceeding –0.4 dB at 28 GHz....
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Comparison of Doppler Effect Estimation Methods for MFSK Transmission in Multipath Hydroacoustic Channel
PublicationUnderwater wireless communication remains a challenging topic, particularly for applications such as wreck penetration where multipath and Doppler effects are very intense. These effects are becoming even more difficult to mitigate for fast data transmission systems that utilize wideband signals. Due to the low propagation speed of acoustic wave in the water, there is a significant difference between the Doppler shift for lower...
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Damped forced vibration analysis of single-walled carbon nanotubes resting on viscoelastic foundation in thermal environment using nonlocal strain gradient theory
PublicationIn this paper, the damped forced vibration of single-walled carbon nanotubes (SWCNTs) is analyzed using a new shear deformation beam theory. The SWCNTs are modeled as a flexible beam on the viscoelastic foundation embedded in the thermal environment and subjected to a transverse dynamic load. The equilibrium equations are formulated by the new shear deformation beam theory which is accompanied with higher-order nonlocal strain...
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Electronic structure of TbBa2Cu3O7
PublicationW pracy wykonano obliczenia kwantowomechaniczne struktury elektronowej hipotetycznego materiału TbBa2Cu3O7 (Dy123) metodą FP-LAPW (full potential - linearized augmented plane wave) w ramach formalizmu DFT (density functional theory) stosując przybliżenie GGA (generalized gradient approximation). Ze względu na silne oddziaływania korelacyjne elektronów 4f w atomie Tb zastosowano dodatkowo poprawkę kulombowską U w ramach modelu...
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Structure and paramagnetism in weakly correlated Y8Co5
PublicationWe report the basic physical properties of monoclinic Y8Co5 determined by means of magnetic susceptibility, electrical resistivity, and specific heat measurements. The crystal structure of Y8Co5 is monoclinic (P21/c) with lattice parameters a = 7.0582(6) Å, b = 7.2894(6) Å, c = 24.2234(19) Å, and β = 102.112(6)° as refined by using synchrotron powder x-ray diffraction data. The compound shows temperature independent paramagnetism...
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Earthquake-Induced Structural Pounding
PublicationEarthquake-induced structural pounding between insufficiently separated build-ings, or bridge segments, has been repeatedly observed during ground motions. The reports after earthquakes indicate that it may lead to some local damage in the case of moderate seismic events or may result in considerable destruction or even collapse of colliding structures during severe ground motions. Pounding in build-ings is usually caused by the...
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Modeling two phase flow in large scale fractured porous media with an extended multiple interacting continua method
PublicationWe present a two phase flow conceptual model, the corresponding simulator (2pMINC) and a workflow for large-scale fractured reservoirs, based on a continuum fracture approach which uses the multiple interacting continua (MINC) method complemented with an improved upscaling technique. The complex transient behavior of the flow processes in fractured porous media is captured by subgridding the coarse blocks in nested volume elements...
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Cost-Efficient Design Methodology for Compact Rat-Race Couplers
PublicationIn this article, a reliable and low-cost design methodology for simulation-driven optimization of miniaturized rat-race couplers (RRCs) is presented. We exploit a two-stage design approach, where a composite structure (a basic building block of the RRC structure) is first optimized using a pattern search algorithm, and, subsequently, the entire coupler is tuned by means of surrogate-based optimization (SBO) procedure. SBO is executed...