Filters
total: 449
Search results for: CRITICAL SECTION
-
Pedestrian safety in road traffic – studies, recommendations and proposed improvements
PublicationPedestrians are involved and most frequently the victims of every third road accident in Poland. Pedestrian accidents most frequently occur in complex circumstances, as a result of many factors related to the behaviour of drivers and pedestrians. The basic parameters that determine road safety include the perception of traffic and visibility on the road. The paper will present the results of research conducted within the project...
-
Road surface roughness estimation employing integrated position and acceleration sensor
PublicationAssessment of a surface quality being an essential task for the authorities supervising the roads provides the subject of the paper. Information about riding quality of a pavement, important for drivers, both in terms of their comfort and safety is collected during experiments employing mobile sensors. The paper describes the use of a miniature position and acceleration sensor for evaluation of the roughness of the road surface....
-
The Effectiveness of Polymer Damper in Damage Reduction of Temporary Steel Grandstand
PublicationA large number of accidents involving damage of temporary grandstands during different types of events were observed in the past. The aim of the paper is to analyse numerically the effectiveness of a polymer damper in damage reduction of a temporary steel scaffolding grandstand exposed to dynamic load due to jumping. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
-
Video content analysis in the urban area telemonitoring system
PublicationThe task of constant monitoring of video streams from a large number of cameras and reviewing the recordings in order to find a specified event requires a considerable amount of time and effort from the system operators and it is prone to errors. A solution to this problem is an automatic system for constant analysis of camera images being able to raise an alarm if a predefined event is detected. The chapter presents various aspects...
-
Assessing unsignalised pedestrian crossings
PublicationThe lack of pedestrian safety on crossings is a complex problem and one that is influenced by a number of factors such as the law, road traffic culture, the road and traffic. This paper will focus on the last two by presenting a method for assessing pedestrian crossings for their geometry and roadside using data from 930 pedestrian crossings in Warsaw. The authors of this paper have attempted to systematise the process of assessment...
-
Sensors for Rapid Detection of Environmental Toxicity in Blood of Poisoned People
PublicationRecently, the diagnosis and treatment of poisoned person can be done only in specialized centers. Furthermore, currently used clinical methods of intoxication diagnosis are not sufficient for early detection. Conventional laboratory tests based on urine and blood require professional, high skilled staff, high cost equipment as well as they are arduous and lasting analytical procedures. There is a need to elaborate relatively cheap...
-
THE CASE OF MANAGEMENT CONCEPTS IN CIVIL AVIATION BUSINESS.
PublicationThe article presents the changes in management concepts used in civil aviation business in last 25 years. There is a need to make prognosis and support decision-making processes with different models but each model is adapted to current management concept. This article will present the changes and possible future trends in management concepts with the description of strengths and weaknesses of each of them. These might be used...
-
Wideband Highly-Selective Bandpass Filtering Branch-Line Coupler
PublicationThis paper presents a novel design of a wideband highly-selective bandpass filtering branch-line coupler (FBLC). By integrating a coupled microstrip line, and an open-ended stub at each port of a single-section BLC, bandpass filtering characteristics with excellent selectivity and broad operating bandwidth have been achieved. The proposed circuit has been verified through EM simulations and physical measurements of the fabricated...
-
Electrolytic corrosion of water pipeline system in the remote distance from stray currents– case study
PublicationCase study of corrosion failure of urban water supply system caused by the harmful effects of stray currents was presented. The failure occurred at a site distant from the sources of these currents namely the tramway and railway traction systems. Diagnosis revealed the stray currents flow to pipeline over a remote distance of 800 ÷ 1,000 meters from the point of failure. At the point of failure stray currents flowed from the pipeline...
-
Optimization of using recuperative braking energy on a double-track railway line
PublicationIn the introduction, possible ways of reusing energy from recuperation are presented. Next, the paper investigates the possibility of using regenerative braking in the range allowed by the detailed timetable by adopting the method of transferring the recovered electric energy directly to the catenary and immediate use of this energy by another train at the same power section. In the main part of the work, it is shown, that the...
-
Selected Stability Problems of Thin-Walled Columns and Beams
PublicationThe article reviews a number of papers in the light of buckling analy- sis of thin-walled columns and beams. Stability of thin-walled columns and beams are considered a vital engineering science issue in both historical and present-day approaches. The paper refers to the recent authors’ works of the 2012–2019 period, published in leading journals. Similar review of stability problems of thin-walled structures developed at Gdansk...
-
Biotrickling filtration of n-butanol vapors: process monitoring using electronic nose and artificial neural network
PublicationBiotrickling filtration is one of the techniques used to reduce odorants in the air. It is based on the aerobic degradation of pollutants by microorganisms located in the filter bed. The research presents the possibility of using the electronic nose prototype combined with artificial neural network for biofiltration process monitoring in terms of reduction in n-butanol concentration and odour intensity of treated air. The study...
-
Impact of Geometrical Imperfections on Estimation of Buckling and Limit Loads in a Silo Segment Using the Vibration Correlation Technique
PublicationThe paper examines effectiveness of the vibration correlation technique which allows determining the buckling or limit loads by means of measured natural frequencies of structures. A steel silo segment with a corrugated wall, stiffened with cold-formed channel section columns was analysed. The investigations included numerical analyses of: linear buckling, dynamic eigenvalue and geometrically static non-linear problems. Both perfect...
-
Soft – Partial Frequency Reuse Method for LTE-A
PublicationIn the paper a novel SPFR frequency reuse method is proposed which can be used for improvement of physical resources utilization efficiency in LTE-A. The proposed method combines both SFR and PFR giving the possibility of more flexible use of frequency band in different regions of a cell. First, a short study on the problem of frequency reuse in cells is discussed including bibliography overview....
-
Cost-efficient simulation-driven design of compact impedance matching transformers
PublicationIn this paper, an algorithmic framework for cost-efficient design optimization of miniaturized impedance matching transformers has been presented. Our approach exploits a bottom-up design that involves translating the overall design specifications for the circuit at hand to its elementary building blocks (here, compact microstrip resonant cells, CMRCs), as well as fast surrogate-assisted optimization of the cells followed by simulation-based...
-
Structural design and sensitivity analysis of semi-rigid pavement of a motorway
PublicationThis paper presents application of mechanistic-empirical methods in design of semi-rigid pavement for a section of a motorway in Poland. The stage construction was assumed. Three fatigue criteria were applied in the design. For asphalt fatigue cracking and subgrade soil the criteria from the Asphalt Institute (USA) were applied. For fatigue cracking of cement stabilized bases the Dempsey (USA) and De Beer (South Africa) criteria...
-
Effects of biotransport and hydro-meteorological conditions on transport of trace elements in the Scott River (Bellsund, Spitsbergen)
PublicationThe shaping of surface water chemistry in the Svalbard Archipelago is strongly dependent on the geology of the catchment and the process of long-range transport of atmospheric pollutants (LRATP). It was found that the dissolved trace elements in the Scott River, which catchment is characterized by a decreasing degree of glaciation, were of the natural origin (i.a. weathering and dissolution of local geological substratum). The...
-
Structures for parameterization, meshing and data exchange of topologically related surfaces of a ship hull
PublicationThis paper presents proposal of data structures for storage and processing of a parametric three-dimensional model of a midship hull sections. The model consists of coarse surfaces like: decks, frames, girders, stiffeners, brackets, partitions etc. bounded by topological relations. All workshop details are omitted as the model is intended for numeric calculations. Proposed data structures are prepared to facilitate changes in the...
-
Modelling of Longitudinal Elastic Wave Propagation in a Steel Rod Using the Discrete Element Method
PublicationThe paper deals with the issue of modelling elastic wave propagation using the discrete element method (DEM). The case of a longitudinal wave in a rod with a circular cross-section was considered. A novel, complex algorithm consisting of the preparation of models and simulation of elastic waves was developed. A series of DEM models were prepared for simulations, differing in discretisation and material parameters. Additional calculations...
-
Compensation of Voltage Drops in Trolleybus Supply System Using Battery-Based Buffer Station
PublicationThis paper analyzes the results of a trial operation of a battery-based buffer station supporting a selected section of trolleybus power supply systems in Pilsen, Czech Republic. The buffer station aims to prevent the catenary from excessive voltage drops in a part of the route that is most remote from the traction substation. Compensation of voltage drops is carried out by continuously measuring the catenary voltage and injecting...
-
Effect of solar radiation on current-carrying capacity of PVC-insulated power cables – the numerical point of view
PublicationPower cables are usually buried in the soil, which results in their relatively high current-carrying capacity. However, there are cases in which the starting/final section of a cable line runs along a pole of an overhead power line. Power cables can be directly exposed to solar radiation then, and this negatively influences their current-carrying capacity as well as estimated life of the cables’ insulation. An analysis of thermal...
-
Estimation of the Maximum Permissible PV Power to be Connected to the MV Grid
PublicationIn recent decades, a significant increase in the share of renewable energy sources in power grids at various voltage levels has been observed. A number of articles have been published highlighting emerging problems in low-voltage grids with a large share of prosumers and in medium- and high-voltage grids to which photovoltaic (PV) plants are connected. The article analyzes the medium-voltage grid in terms of the possibility of...
-
Analysis of the Hydrodynamic Properties of the 3-Column Spar Platform for Offshore Wind Turbines
PublicationThe article presents a design of a floating platform for offshore wind turbines. The concept is a modification of the Spar design and consists of three variable section columns connected to each other by a ballast tank in the lower part of the platform. This solution makes it possible to influence the position of the centre of buoyancy and the centre of mass of the structure. Compared to the classic Spar platform structure, the...
-
Standard IEC 61850 w sieci rozdzielczej średniego napięcia CERN
PublicationArtykuł stanowi skrótowy opis wyników pracy autora w okresie od 01.10.2009 do 30.09.2010 w Engineering Department, High-Voltage Section w CERN. Przedstawiono system zasilania elektroenergetycznego obiektów CERN wraz automatyką ATS w sieci 18 kV. Zdefiniowano założenia dla automatyki w ramach planowanych modernizacji sieci średniego napięcia, wskazując na wymóg zgodności ze standardem IEC 61850. Zaproponowano trójpierścieniową topologię...
-
Dynamic tests of composite footbridge segment – experimental and numerical studies
PublicationExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
-
Approaches to Static Digestion Models
PublicationIt is not possible to look in detail at the wide range of static digestion methods that have been used to date. However, this section looks at some of the general approaches that have been used to look at the digestion of various nutrients and bioactives. I have focussed on the two main nutrients that undergo digestion in the upper GI tract, namely protein and lipid. In the case of protein, the research has largely been driven...
-
Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublicationUltrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...
-
Determination of the optimal curvature of the turnout diverging track for HSR using dynamic analysis
PublicationThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Such turnout is mainly applied on High Speed Railway. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are considered in the paper. Obtained solutions enable to assume curvature values at the beginning and end point of the geometrical layout of the turnout.The...
-
Electron interactions with Bis(pentamethylcyclopentadienyl) titanium(IV) dichloride and difluoride
PublicationWe present a combined experimental and theoretical study of the interaction of electrons with Bis(pentamethylcyclopentadienyl)titanium(IV) dichloride (Cp∗2TiCl2) and difluoride (Cp∗2TiF2). We report the experimental measurements of partial cross sections for the dissociative electron attachment (DEA) and the electron ionization (EI) mass spectra of isolated molecules. Estimates of the absolute cross sections are done on the basis...
-
Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublicationThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
-
Finite element/mode-matching analysis of ferrite/dielectric line junctions of arbitrary cross-section
PublicationThis paper is focused on the analysis of line junctions obtained as a cascade of dielectric and ferrite guides of arbitrary cross-section. The main application of such structures is nonreciprocal devices such as isolators, circulators, or phase shifters. The efficient finite element/mode-matching approach is proposed to the analysis of such structures. In this approach, thefiniteelementmethod is applied todetermine propagation...
-
Multi-objective optimization of compact UWB impedance matching transformers using Pareto front exploration and adjoint sensitivities
PublicationIn this paper, a technique for fast multi-objective optimization of impedance matching transformers has been presented. In our approach, a set of alternative designs that represent the best possible trade-offs between conflicting objectives (here, the maximum reflection level within a frequency band of interest and the circuit size) is identified by directly exploring the Pareto front. More specifically, the subsequent Pareto-optimal...
-
THEORETICAL POTENTIAL OF HYDROGEN PRODUCTION FROM TEXTILES WASTES IN POMERANIAN REGION BY MEANS OF DARK FERMENTATION
PublicationModel has been developed for calculating theoretical mass of hydrogen produced from textile wastes by mean of dark fermentation. As vegetable fibres wastes were chosen two mostly used — cotton and linen (flax). As the synthethic carbohydrate rich fiber was chosen viscose. In the background there were introduced: problems of dark fermentation, characteristics of textile material structure. Additionally pathways of the process...
-
Application of Least Squares with Conditional Equations Method for Railway Track Inventory Using GNSS Observations
PublicationSatellite geodetic networks are commonly used in surveying tasks, but they can also be used in mobile surveys. Mobile satellite surveys can be used for trackage inventory, diagnostics and design. The combination of modern technological solutions with the adaptation of research methods known in other fields of science offers an opportunity to acquire highly accurate solutions for railway track inventory. This article presents the...
-
Drewno w adoptowanym zabytku - studium przypadku. Budynek nr 2 w dawnych koszarach garnizonu we Wrzeszczu
PublicationThe current structure along with adapted listed buildings and surroundings will create "Garrison of Culture".This part of Gdańsk and Wrzeszcz has been reconnected after eight decades of isolation from the city by joining the square area formed by Grunwaldzka, Słowackiego, Chrzanowskiego, Szymanowskiego streets and the city center. It is a project whitch fits into an aspect of revitalisation related to the socio-economic and environmental...
-
Technical diagnostics and monitoring of traction current collectors
PublicationNew evaluation methods of the technical condition of rolling stock current collectors are proposed in this paper. The method of automatic measurement of the pantograph static force characteristic, realized when the vehicle runs through the test section of the track with especially prepared overhead line height distribution, has been practically implemented by the Polish Railways. The method of testing the slipper spring suspension...
-
Compact Dual-Polarized Corrugated Horn Antenna for Satellite Communications
PublicationIn this paper, a structure and design procedure of a novel compact dual-polarized corrugated horn antenna with high gain and a stable phase center for satellite communication is presented. The antenna incorporates an Ortho-Mode Transducer (OMT), a mode converter, and a corrugated structure. The compact OMT section is designed to be fed by standard WR-75 waveguides. The proposed compact design utilizes only ten corrugated slots...
-
Analysis of the Environmental Impact of the Hull Construction of a Small Vessel Based on LCA
PublicationIn recent years, issues related to the impact of human activity on the natural environment have become pressing, and the challenge of global warming necessitates immediate action. To support environmental protection efforts, it has become imperative to adopt a broader perspective when evaluating various products and systems. A valuable tool for such assessments is a life cycle assessment (LCA), which enables a comprehensive analysis...
-
Vibration-Based Investigation of a Historic Bell Tower to Understand the Occurrence of Damage
PublicationABSTRACT The paper presents a survey of the historic Arch-cathedral bell tower in Vilnius induced by the appearance of cracks in the structure after a new bell system installation. An attempt is undertaken to identify the reason for the crack occurrence and to check a possible crack influence on global structural behaviour. The research is based on dynamic measurements made in the tower during ambient vibrations and during vibrations...
-
60 GHz Microstrip Van Atta Arrays for Millimeter Wave Identification and Localization
PublicationIn this paper performance comparison of co-polarized and cross-polarized microstrip Van Atta arrays working in the 60 GHz frequency range is presented. They can be treated as simple chipless RFID tags with frequency response based identification. Tags with three different nominal resonance frequencies of 57, 62 and 67 GHz are designed by scaling optimized base model. Designed 62 GHz co-polarized and cross-polarized arrays with...
-
Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublicationA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
-
Experimental bases for the rail track surface damage detection system
PublicationA diagnosis of rail surface is generally based on the classical method of direct assessment and track geometry measurements. Identification and qualification of inequality and damage on the surface rails is depend on the skills and experience person who conducting inspection. In times of increasing exploitation of railways, infrastructure managers decide to use systems supporting the assessment of technical condition of the railways....
-
Application of Spinel and Hexagonal Ferrites in Heterogeneous Photocatalysis
PublicationSemiconducting materials display unique features that enable their use in a variety of applications, including self-cleaning surfaces, water purification systems, hydrogen generation, solar energy conversion, etc. However, one of the major issues is separation of the used materials from the process suspension. Therefore, chemical compounds with magnetic properties have been proposed as crucial components of photocatalytic composites,...
-
Sound engineering as our commitment to its creators in Poland
PublicationSound engineering is an interdisciplinary and rapidly expanding domain. It covers many aspects, such as sound perception, studio and sound mastering technology, music information retrieval including content-based search systems and automatic music transcription frameworks, sound synthesis, sound restoration, electroacoustics, and other ones constituting multimedia technology. Moreover, machine learning methods applied to the topics...
-
Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublicationOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
-
Electron scattering from tin tetrachloride (SnCl4) molecules
PublicationAbsolute grand-total cross section (TCS) for electron scattering from a tin tetrachloride, SnCl4, molecule was measured at electron-impact energies ranging from 0.6 to 300 eV, in the linear electron-transmission experiment. The measured TCS energy dependence shows two very pronounced enhancements peaking near 1.2 eV and around 9.5 eV, separated with a deep minimum centered close to 3 eV. The low energy structure is attributed to...
-
Security of export transactions in the offer of leading banks on the Polish market
PublicationThe following article presents the so-called conditioned payment methods, i.e. instruments for securing export transactions, such as letter of credit, documentary collection, bank guarantees, factoring and forfaiting. The characteristics of each particular method are presented as well as the transactions using them are described. In the following paper, the author included also the leading Polish banks, which offer the above- mentioned...
-
Resonances and Dissociative Electron Attachment in HNCO
PublicationIn a combined experimental and theoretical study, we probe the dissociative electron attachment in isocyanic acid HNCO. The experimental absolute cross section for the NCO− fragment shows a sharp onset and fine structures near the threshold. The autoionizing state responsible for the dissociative attachment is found in both the R-matrix calculation and using analytic continuation in the coupling constant. The involved A' resonance...
-
Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublicationIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
-
Electron collisions with cyanoacetylene HC3N : Vibrational excitation and dissociative electron attachment
PublicationWe experimentally probe electron collisions with HC3N in the energy range from 0 to 10 eV with the focus on vibrational excitation and dissociative electron attachment. The vibrational excitation cross sections show a number of resonances which are mode specific: the two dominant π∗ resonances are visible in the excitation of all the vibrational modes; however, broad σ ∗ resonances are visible only in certain bond-stretching vibrational...