Filters
total: 1138
filtered: 989
Search results for: RAILWAY TRACK GEOMETRY
-
Global EM-Driven Optimization of Multi-Band Antennas Using Knowledge-Based Inverse Response-Feature Surrogates
PublicationElectromagnetic simulation tools have been playing an increasing role in the design of contemporary antenna structures. The employment of electromagnetic analysis ensures reliability of evaluating antenna characteristics but also incurs considerable computational expenses whenever massive simulations are involved (e.g., parametric optimization, uncertainty quantification). This high cost is the most serious bottleneck of simulation-driven...
-
Self-standing Nanoarchitectures
PublicationDespite there are structures invisible for the human eye, they mastered the world of advanced electronic devices, sensors, novel cosmetics or drugs. When the dimensions of the materials go down to the nanometres scale, their properties change dramatically comparing to the observable objects. Because of their tiny size, they gained the name of nanomaterials but simultaneously their importance has significantly grown up. Nanomaterials...
-
Recent advances in high-frequency modeling by means of domain confinement and nested kriging
PublicationDevelopment of modern high-frequency components and circuits is heavily based on full-wave electromagnetic (EM) simulation tools. Some phenomena, although important from the point of view of the system performance, e.g., EM cross-coupling effects, feed radiation in antenna arrays, substrate anisotropy, cannot be adequately accounted for using simpler means such as equivalent network representations. Consequently, the involvement...
-
ANALYSIS OF THE RESULTS OF THE AUDIT OF LIGHTING PARAMETERS AT PEDESTRIAN CROSSINGS IN WARSAW
PublicationThe night time, based on many world studies, generates an increased risk of serious accidents (with fatalities and serious injuries). This is especially true for accidents with pedestrians. Pedestrian crossings are very sensitive to the influence of the time of day in terms of pedestrian safety, elements of road infrastructure. This is visible on the example of Poland, where numerous accidents at crosswalks are recorded, characterized...
-
Complex multidisciplinary optimization of turbine blading systems
PublicationThe paper describes the methods and results of direct optimization of turbine blading systems using a software package Opti_turb. The final shape of the blading is obtained from minimizing the objective function, which is the total energy loss of the stage, including the leaving energy. The current values of the objective function are found from 3D RANS computations (from a code FlowER) of geometries changed during the process...
-
Fracture in Asymmetric Bonded Joints
PublicationAdhesion was studied in asymmetric bonded joints using fracture mechanics tests. The asymmetric bonded joints consist of two different type and/or thickness materials bonded by an adhesive. Mentions of asymmetric bonded joint tests employed so far are rare in the literature. They are imperfect and therefore are not standardized. Accordingly three new tests were introduced in this work to study bonded joints. The new metrological...
-
The method of analysis of damage reinforced concrete beams using terrestial laser scanning
PublicationThe authors present an analysis of the possibility to assess deformations and mechanisms of destructing bent reinforced concrete beams using the terrestrial laser scanning. As part of the experiments carried out at the Regional Laboratory of Construction of the Concrete Structures Division of the Civil and Environmental Engineering Faculty at Gdansk University of Technology, the reinforced concrete beams were subjected to destruction...
-
Shoreline Extraction Based on LiDAR Data Obtained Using an USV
PublicationThis article explores the use of Light Detection And Ranging (LiDAR) derived point clouds to extract the shoreline of the Lake Kłodno (Poland), based on their geometry properties. The data collection was performed using the Velodyne VLP‐16 laser scanner, which was mounted on the HydroDron Unmanned Surface Vehicle (USV). A modified version of the shoreline extraction method proposed by Xu et al. was employed, comprising of the following...
-
Insight into (Electro)magnetic Interactions within Facet-Engineered BaFe12O19/TiO2 Magnetic Photocatalysts
PublicationA series of facet-engineered TiO2/BaFe12O19 composites were synthesized through hydrothermal growth of both phases and subsequent deposition of the different, faceted TiO2 nanoparticles onto BaFe12O19 microplates. The well-defined geometry of the composite and uniaxial magnetic anisotropy of the ferrite allowed alternate interfaces between both phases and fixed the orientation between the TiO2 crystal structure and the remanent...
-
Dimensionality-Reduced Antenna Modeling with Stochastically Established Constrained Domain
PublicationOver the recent years, surrogate modeling methods have become increasingly widespread in the design of contemporary antenna systems. On the one hand, it is associated with a growing awareness of numerical optimization, instrumental in achieving high-performance structures. On the other hand, considerable computational expenses incurred by massive full-wave electromagnetic (EM) analyses, routinely employed as a major design tool,...
-
Cost-Efficient Two-Level Modeling of Microwave Passives Using Feature-Based Surrogates and Domain Confinement
PublicationA variety of surrogate modelling techniques has been utilized in high-frequency design over the last two decades. Yet, the curse of dimensionality still poses a serious challenge in setting up re-liable design-ready surrogates of modern microwave components. The difficulty of the model-ing task is only aggravated by nonlinearity of circuit responses. Consequently, constructing a practically usable surrogate model, valid across...
-
Rapid Design Centering of Multi-Band Antennas Using Knowledge-Based Inverse Models and Response Features
PublicationAccounting for manufacturing tolerances as well as uncertainties concerning operating conditions and material parameters is one of the important yet often neglected aspects of antenna development. Appropriate quantification of uncertainties allows for estimating the fabrication yield but also to carry out robust design (e.g., yield maximization). For reliability reasons, statistical analysis should be executed at the accuracy level...
-
Direct-contact condensation from vapour- gas mixture in a spray ejector condenser for negative CO2 power plant
PublicationDirect-contact condensation of vapour containing the inert gas on a spray of subcooled liquid exists in a number of technical applications. For example, it may be found in the nuclear industry (e.g. pressurized jet under normal operating conditions, in safety analyses) or in the chemical industry (e.g. mixing-type heat exchanger, degasser, sea water desalting). The problem is also essential to modelling and analysis of some...
-
Optimization-Based Robustness Enhancement of Compact Microwave Component Designs with Response Feature Regression Surrogates
PublicationThe ability to evaluate the effects of fabrication tolerances and other types of uncertainties is a critical part of microwave design process. Improving the immunity of the device to parameter deviations is equally important, especially when the performance specifications are stringent and can barely be met even assuming a perfect manufacturing process. In the case of modern miniaturized microwave components of complex topologies,...
-
Fire Protection and Materials Flammability Control by Artificial Intelligence
PublicationFire safety has become a major challenge of materials developers because of the massive production of organic materials, often combustibles, and their use for different purposes. In this sense, fire safety is critically considered in the development of engineering materials [1, 2]. The multiplicity of parameters contributing to the development of formulation of flame-retardant materials from one side and the sustainability concerns...
-
Expedited Yield-Driven Design of High-Frequency Structures by Kriging Surrogates in Confined Domains
PublicationUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of high-frequency structures systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the characteristics of antennas or microwave devices. For example, in the case...
-
Wybrane zagadnienia optymalizacji organizacji ruchu kolejowego w celu minimalizacji kosztów energii elektrycznej
PublicationW artykule przedstawiono podział kosztów w transporcie kolejowym z uwzględnieniem kosztów wewnętrznych przedsiębiorstwa, do których zaliczają się między innymi koszty dostępu do infrastruktury, czy koszty energii. Stwierdzono, że przy odpowiedniej organizacji ruchu pociągów na sieci kolejowej, bez ponoszenia dodatkowych nakładów na infrastrukturę i specjalistyczne urządzenia, można znacznie ograniczyć zużycie energii, a co za tym...
-
Similarities and differences in d6 low-spin ruthenium, rhodium and iridium half-sandwich complexes: synthesis, structure, cytotoxicity and interaction with biological targets
PublicationIn this paper, we discussed the similarities and diferences in d6 low-spin half-sandwich ruthenium, rhodium and iridium complexes containing 2,2′-biimidazole (H2biim). Three new complexes, {[RuCl(H2biim)(η6 -p-cymene)]PF6}2·H2O (1), [(η5 - Cp)RhCl(H2biim)]PF6 (2), and [(η5 -Cp)IrCl(H2biim)]PF6 (3), were fully characterized by CHN, X-ray difraction analysis, UV–Vis, FTIR, and 1 H, 13C and 15N NMR spectroscopies. The complexes exhibit...
-
Application of Msplit method for filtering airborne laser scanning data sets to estimate digital terrain models
PublicationALS point cloud filtering involves the separation of observations representing the physical terrain surface from those representing terrain details. A digital terrain model (DTM) is created from a subset of points representing the ground surface. The accuracy of the generated DTM is influenced by several factors, including the survey method used, the accuracy of the source data, the applied DTM generation algorithm, and the survey...
-
Structural, magnetic and spectral properties of tetrahedral cobalt(II) silanethiolates: a variety of structures and manifestation of field-induced slow magnetic relaxation
PublicationBlue crystals of five heteroleptic cobalt(II) silanethiolates 1–5 have been obtained by the reaction of [Co{SSi (tBuO)3}2(NH3)]2 with aminopyridines and aminomethylpyridines at an appropriate molar ratio and their structural, spectral, thermal and magnetic properties have been established and described. All complexes 1–5 contain Co(II) ions in a tetrahedral CoN2S2 environment formed by (tBuO)3SiS− residues and pyridines and present...
-
Fast multi-objective optimization of antenna structures by means of data-driven surrogates and dimensionality reduction
PublicationDesign of contemporary antenna structures needs to account for several and often conflicting objectives. These are pertinent to both electrical and field properties of the antenna but also its geometry (e.g., footprint minimization). For practical reasons, especially to facilitate efficient optimization, single-objective formulations are most often employed, through either a priori preference articulation, objective aggregation,...
-
On the Possibilities of Decreasing Power Loss in Large Tilting Pad Thrust Bearings
PublicationJournal Menu About this Journal Abstracting and Indexing Aims and Scope Article Processing Charges Articles in Press Author Guidelines Bibliographic Information Citations to this Journal Contact Information Editorial Board Editorial Workflow Free eTOC Alerts Publication Ethics Submit a Manuscript Table of Contents Abstract Full-Text PDF Full-Text HTML...
-
ASSESSMENT OF CLIFF STABILITY AFTER THE DEMOLITION OF THE ENGINEERING FACILITIES
PublicationAs a part of an experiment, cliff in Gdynia Redlowo (southern coast of Baltic Sea, Gdansk Bay) was measured using terrestrial laser scanner. The main reason for taking up the subject of the Orlowo Cliff’s stability was a decision about controlled removal one of the war fortification elements. The main purpose of that analysis was to specify suitability of laser scanning in determination of slope’s stability after a violent event....
-
THE METHOD OF ANALYSIS OF DAMAGE REINFORCED CONCRETE BEAMS USING TERRESTRIAL LASER SCANNING
PublicationThe authors present an analysis of the possibility to assess deformations and mode of failure of R-C beams using terrestrial laser scanning. As part of experiments carried out at the Regional Laboratory of Construction (at Gdansk University of Technology), reinforced concrete beams were subjected to destruction by bending and by shear. The process of press impact on the reinforced concrete beam was recorded using terrestrial laser...
-
System of monitoring of the Forest Opera in Sopot structure and roofing
PublicationThe authors present a solution realized in Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland) in connection with the modernization and construction of a new roof. The complicated structure of the roof of the facility and the used covering in form of membrane made of technical fabric required (for security reasons) to install the unit of devices allowing for the continuous geodetic monitoring of the facility. Monitoring...
-
Application of the Msplitmethod for filtering airborne laser scanning data-sets to estimate digital terrain models
PublicationALS point cloud filtering involves the separation of observations representing the physical terrain surface from those representing terrain details. A digital terrain model (DTM) is created from a subset of points representing the ground surface. The accuracy of the generated DTM is influenced by several factors, including the survey method used, the accuracy of the source data, the applied DTM generation algorithm, and the survey...
-
High-Efficacy Global Optimization of Antenna Structures by Means of Simplex-Based Predictors
PublicationDesign of modern antenna systems has become highly dependent on computational tools, especially full-wave electromagnetic (EM) simulation models. EM analysis is capable of yielding accurate representation of antenna characteristics at the expense of considerable evaluation time. Consequently, execution of simulation-driven design procedures (optimization, statistical analysis, multi-criterial design) is severely hindered by the...
-
On Accelerated Metaheuristic-Based Electromagnetic-Driven Design Optimization of Antenna Structures Using Response Features
PublicationDevelopment of present-day antenna systems is an intricate and multi-step process requiring, among others, meticulous tuning of designable (mainly geometry) parameters. Concerning the latter, the most reliable approach is rigorous numerical optimization, which tends to be re-source-intensive in terms of computing due to involving full-wave electromagnetic (EM) simu-lations. The cost-related issues are particularly pronounced whenever...
-
Designing acoustic scattering elements using machine learning methods
PublicationIn the process of the design and correction of room acoustic properties, it is often necessary to select the appropriate type of acoustic treatment devices and make decisions regarding their size, geometry, and location of the devices inside the room under the treatment process. The goal of this doctoral dissertation is to develop and validate a mathematical model that allows predicting the effects of the application of the scattering...
-
Circularly Polarized Antenna Array design with the Potential of Gain-Size Trade-off and Omnidirectional Radiation for Millimeter-Wave Small Base Station Applications
PublicationThis paper presents the design and validation of a slot-patch-hybrid circularly polarized antenna array for 28 GHz millimeter (mm) wave (mm-wave) applications. The proposed design has a simple geometry that facilitates the fabrication process, which is otherwise a challenging task due to the sub-mm dimensions of the circuit in the mm-wave band. In the proposed structure, aperture-coupled series slot-fed array is utilized to excite...
-
Low-Cost Quasi-Global Optimization of Expensive Electromagnetic Simulation Models by Inverse Surrogates and Response Features
PublicationConceptual design of contemporary high-frequency structures is typically followed by a careful tuning of their parameters, predominantly the geometry ones. The process aims at improving the relevant performance figures, and may be quite expensive. The reason is that conventional design methods, e.g., based on analytical or equivalent network models, often only yield rough initial designs. This is especially the case for miniaturized...
-
Accurate Modeling of Antenna Structures by Means of Domain Confinement and Pyramidal Deep Neural Networks
PublicationThe importance of surrogate modeling techniques has been gradually increasing in the design of antenna structures over the recent years. Perhaps the most important reason is a high cost of full-wave electromagnetic (EM) analysis of antenna systems. Although imperative in ensuring evaluation reliability, it entails considerable computational expenses. These are especially pronounced when carrying out EM-driven design tasks such...
-
Biomechanics of the medial meniscus in the osteoarthritic knee joint
PublicationBackground. Increased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA...
-
The carbohydrate glycosylphosphatidylinositol anchor chain under mechanical stress
PublicationCarbohydrates have quite complicated micro heterogenic structure which may undergo different structural transitions. Due to their extreme flexibility it is very difficult to investigate such structural changes experimentally. In these studies we want to predict what structural and conformational changes are possible in the carbohydrate
-
On the influence of shell element properties on the response of car model in crash test
PublicationIt goes without saying that numerical simulations play important role in the modern engineering practice. Contemporary CAD environments combined with FEM solvers, along with computer power of modern processors, give the engineer fast and efficient tool. Ultimately, however it is the user alone who is responsible for the correctness of the results. As long as the FEM calculations remain in the sphere of academic exercise, the inevitable...
-
The role of organic and mineral constituents on kerogen transformation ratio
PublicationThe main aim of this dissertation is to determine the role of mineral and organic matter constituents in kerogen transformation ratio. Practical aspects of the work include application of the results in the assessment of hydrocarbon production potential; to make process of hydrocarbon recovery more predictable consistent and efficient. The work used shale from the Vaca Muerta formation from the Nequen basin in Argentina. The formation...
-
Advancements in the Additive Manufacturing of Magnesium and Aluminum Alloys through Laser-Based Approach
PublicationComplex structures can now be manufactured easily utilizing AM technologies to meet the pre-requisite objectives such as reduced part numbers, greater functionality, and lightweight, among others. Polymers, metals, and ceramics are the few materials that can be used in AM technology, but metallic materials (Magnesium and Aluminum) are attracting more attention from the research and industrial point of view. Understanding the role...
-
On Nature-Inspired Design Optimization of Antenna Structures Using Variable-Resolution EM Models
PublicationNumerical optimization has been ubiquitous in antenna design for over a decade or so. It is indispensable in handling of multiple geometry/material parameters, performance goals, and constraints. It is also challenging as it incurs significant CPU expenses, especially when the underlying computational model involves full-wave electromagnetic (EM) analysis. In most practical cases, the latter is imperative to ensure evaluation reliability....
-
Cobalt(II) tri-tert-butoxysialanethiolates.Synthesis, properties, crystal and molecular structures of [Co{SSi(OtBu)3}2(L)] and[Co{SSi(OtBu)3}2(L)2] type complexes with monodentate nitrogen ligands.
PublicationThe title heteroleptic neutral cobalt(II) tri-tert-butoxysilanethiolate complexes with monodentate nitrogen bases (L) as additional ligands have been prepared by the reactions of [Co{μ-SSi(OtBu)3}{SSi(OtBu)3}(NH3)]2 (1) with respective bases. For pyridine both types have been prepared...