Filters
total: 1203
filtered: 1049
displaying 1000 best results Help
Search results for: COLD-FORMED PROFILES, BUCKLING LOAD, LIMIT LOAD.
-
Probabilistic Methods in Reliability Assessment of Engineering Lightweight Structures
PublicationThe paper considers the probability-based analysis of structural safety measures. Two different numerical examples of representative lightweight structures are considered – a submerged truss tower supporting an offshore platform, and an overhead power line support truss tower. On the basis of these examples, the importance of a motivated selection of analysis method and a proper choice of the number of important variables is shown....
-
Shear Cap Size Selection Method Based on Parametric Analysis of ACI-318 Code and Eurocode 2 Standard
PublicationThe scope of the paper is to propose a method for determining the size of shear caps in a slab–column-connections-reinforced concrete structure. Usually, shear heads are used to enhance slab–column connection, especially when the transverse reinforcement does not give the required punching shear load capacity. The dimensions of the shear head should provide the punching shear resistance of the connection inside and outside the...
-
Two-dimensional simulations of concrete fracture at aggregate level with cohesive elements based on X-ray lCT images
PublicationThe paper presents results of two-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 4-phase material composed of aggregate grains placed in the cement matrix, interfacial transitional zones (ITZs) and macro-voids. The particle distribution was taken from real concrete beams on the basis of X-ray lCT images. Comprehensive numerical analyses were carried...
-
Naprawa po pożarze stalowej wielokondygnacyjnej wieży produkcyjnej z zastosowaniem sprężanych elementów wzmocnienia
PublicationPożar we wnętrzu wielokondygnacyjnego obiektu produkcyjnego o stalowej konstrukcji ramowej spowodował znaczne uszkodzenia w zakresie stalowych stropów międzykondygnacyjnych oraz części głównych słupów nośnych obiektu. Pomimo dużych strat w obrębie konstrukcji i lekkiej obudowy obiektu oraz długiej akcji gaśniczej udało się uratować w całości baterię technologicznych silosów magazynowych zlokalizowanych na jego dachu. Wydane bezpośrednio...
-
Mathematical Modeling of Ice Thrusting on the Shore of the Vistula Lagoon (Baltic Sea) and the Proposed Artificial Island
PublicationCoastal lagoons are inland and shallow water bodies, separated from the ocean by a barrier. In cold regions, ice phenomena in shallow water coastal lagoons occur every winter season. Ice is predominantly formed on the surface due to density stratification and surface cooling. The ice dynamics in such areas are dominantly affected by winds. Water dynamics also cause ice movement, but due to the large areal scale of lagoons, the...
-
Badania i analizy kolejowych konstrukcji odciążających typu mostowego
PublicationW pracy przedstawiono i omówiono wybrane modele obliczeniowe, wyniki analiz teoretycznych oraz badań trzech typów kolejowych konstrukcji odciążających typu mostowego. Zaprezentowano modele obliczeniowe oraz metodykę badań in situ tego typu konbstrukcji. Przedstawiono wnioski dotyczące zaawansowanych metod obliczeniowych rozszerzonych badań in situ w celu diagnozowania rzeczywistej pracy obiektów mostowych.
-
Wpływ kierowcy na opór toczenia samochodu
PublicationW pracy omówiono wpływ zachowań kierowcy na opory toczenia pojazdu w ruchu drogowym. Można tu wyróżnić styl jazdy kierowcy oraz jego dbałość o pojazd. Przedstawiono wzrost oporu toczenia w aspekcie dynamicznego przyspieszania oraz szybkiej jazdy na zakręcie. Przeanalizowano także wpływ na opór toczenia takich czynników jak: ciśnienie w ogumieniu obciążenie promieniowe, zbieżność kół jezdnych samochodu oraz zużycie ogumienia.
-
Most Uniwersytecki w Bydgoszczy. Teoretyczne podstawy decyzji o wyłączeniu obiektu z ruchu
PublicationW artykule przedstawiono ogólny opis konstrukcji podwieszonego mostu Uniwersyteckiego nad rzeką Brdą w Bydgoszczy. Opisano również prace eksperckie dotyczące oceny nośności konstrukcji. W wyniku badań i analiz obiekt został uznany za niebezpieczny dla użytkowników i wycofany z eksploatacji. W artykule przedstawiono zasadnicze przesłanki, które doprowadziły zarządcę do podjęcia głównych decyzji i postępowania naprawczego.
-
Instalacje fotowoltaiczne w budownictwie wielorodzinnym
PublicationArtykuł opisuje wpływ instalacji fotowoltaicznych na bezpieczeństwo eksploatacji budynków wielorodzinnych. W oparciu o projekty rzeczywistych obiektów przeprowadzono analizę zwiększenia ryzyka strat odgromowych, zmiany obciążenia konstrukcji dachu i wzrostu zagrożenia pożarowego na skutek montażu systemu fotowoltaicznego. Przeprowadzone obliczenia wskazują na konieczność kompleksowego podejścia do projektowania instalacji fotowoltaicznych....
-
Badania charakterystyki obciążeń oddziałujących na modułowe urządzenie dylatacyjne w pasie ruchu ciężkiego autostrady A8
PublicationPrzedstawiono badania urządzenia dylatacyjnego typu nożycowego. Dokonano statycznych i dynamicznych pomiarów odkształceń oraz przemieszczeń konstrukcji nożyc na najbardziej obciążonym pasie autostrady A8. Określono wpływ oddziaływania dynamicznego oraz sporządzono histogramy obciążeń i współczynników przewyższenia dynamicznego na podstawie pomiarów ciągłych w okresie nasilonego ruchu. Wskazano przyczyny degradacji urządzenia. Odniesiono...
-
Fundamenty palowe, obliczenia z zastosowaniem zasad Eurokodu 7 i doświadczeń krajowych
PublicationPrzedstawiono zagadnienia obliczania fundamentów palowych w nawiązaniu do zaleceń Eurokodu 7. Zwrócono uwagę, że zgodnie z założeniami Eurokodu 7, projektant i inżynier ma swobodę w wyborze metod obliczeniowych.Przytoczono i zarekomendowano metody i propozycje miedzy innymi obliczania statycznego układów palowych, określania nośności pali, prognozowania osiadań fundamentów palowych oraz charakterystyk obciążenie-osiadanie pali...
-
Method of selective fading as a educational tool to study the behaviour of prestressed concrete elements under excess loading
PublicationPrestressed structures are a key to realization of the boldest architectural ideas, characteristic feature of prestressed structure is better use of concrete material properties by insertion of internal forces. Learning about pre-stressed reinforced concrete structures is an integral part of Graduate Studies Program in construction engineering. Know-how of geometry change patterns in prestressed concrete elements under certain...
-
Badania eksperymentalne transformatora hybrydowego jako kondycjonera napięcia w sieciach typu TN
PublicationArtykuł dotyczy układu dystrybucyjnego transformatora hybrydowego (DTH) przeznaczonego do zastosowania w sieciach typu TN. Opisano w nim sposoby podłączenia przewodu neutralnego do układu DTH. W dalszej części artykuł zawiera opis skonstruowanego modelu laboratoryjnego o mocy 16 kVA wraz z zastosowanym algorytmem sterowania. Ponadto przedstawiono wyniki badań eksperymentalnych, ze szczególnym uwzględnieniem oceny dokładności stabilizacji...
-
Badania laboratoryjne wybranych sposobów koordynacji regulatora transformatora blokowego oraz regulatora generatora
PublicationWprowadzenie wymogu stosowania transformatorów blokowych z przekładnią regulowaną pod obciążeniem spowodowało konieczność określenia właściwego sposobu podziału kryteriów sterowania pomiędzy regulator generatora a regulator transformatora blokowego. W referacie zwrócono uwagę na aspekt miejsca pomiaru napięć. Ma to istotny wpływ zarówno na algorytm jak i jakość regulacji. Rozważania teoretyczne zilustrowane zostały wynikami prób...
-
Przyczółki mostowe wspomagane konstrukcjami z gruntu zbrojonego
PublicationW referacie przedstawiono syntezę prac związanych z oceną projektów przyczółków wykorzystujących odciążenie w postaci konstrukcji z gruntu zbrojonego geosyntetykami, realizowanych na drogach ekspresowych S3 i S7. W ramach przeprowadzonych audytów dokonano oceny zastosowanych rozwiązań szczegółowych i materiałów jak również obliczeń zamieszczonych w projektach. Zwrócono szczególną uwagę na przestrzenną prace bloków z gruntu zbrojonego...
-
Simulation model for evaluation of QoS routing algorithm in large packet networks
PublicationThe variety of traffic transferred via current telecommunication networks includes also voice, which should meet quality requirements. One of mechanisms, which can support QoS in current packet networks, is routing. There exist many routing proposals which should introduce the QoS into the network but practically they don't. Following paper presents the realization of simulation model for evaluation of a new routing algorithm DUMBRA...
-
Water and chemical properties of hydrometeors over central european mountains
PublicationAtmospheric pollutants are transferred to the groundby the contribution of various types of hydrometeors. Because ofthe different techniques of measurement, comparative analysesbetween them are often neglected. Hence, the main goal is tocompare water volume and chemistry of different types ofhydrometeors and their role in both: water balance and pollutantsdeposition. The results of water input and atmospheric depositschemistry...
-
Developing a methodology for model tests of floating platforms in a towing tank of low depth
PublicationThe paper presents two ways to mooring model of semi-submersible platform for research in the small depth towing pool. The tested model was made in the likeness of 1:100 Thunder Horse platform moored in the Gulf of Mexico at a depth of 1,920 m. Its mooring system consisted of 16 semi-taut mooring lines (chain-wire-chain) spaced Star-shape and attached at the bottom to the suction piles. The tests were performed in the towing pool...
-
Study of railway traffic safety based on the railway track condition monitoring system
PublicationThe solution to the problem of monitoring the railway track, as well as potentially dangerous objects and phenomena in the adjacent territories, is determined by the need to implement increased requirements for traffic safety (primarily to the geometric parameters of the devices of a long railway track under construction and functioning load-bearing highways), prevention of technological disasters and large-scale negative effects...
-
A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublicationIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
-
Improving Output Performance of the Ultrasonic Multicell Piezoelectric Motor by Development the Multi-Rotor Structure
PublicationIn recent years, many researches have been carried out on piezoelectric multi-rotor structures. This paper describes the analysis, development and experimental process of an ultrasonic multi-cell piezoelectric motor using a multi-rotor structure. In this design, three independent cells have been integrated into a mechatronic system. Analytical model and finite element method are used for modal and dynamic analysis of the proposed...
-
Thermo-mechanical reclaiming of ground tire rubber via extrusion at low temperature: Efficiency and limits
PublicationThermomechanical reclaiming of ground tire rubber (GTR) was performed at different temperatures (60, 120, and 180°C) using a co-rotating twin-screw extruder. Obtained samples were used in styrene-butadiene rubber (SBR) blends. As reference samples, SBR compounds containing untreated GTR were used. Curing characteristics, static and dynamic mechanical properties, and morphology of the obtained blends were determined. The results...
-
MODELLING OF TOXIC COMPOUNDS EMISSION IN MARINE DIESEL ENGINE DURING TRANSIENT STATES AT VARIABLE PRESSURE OF FUEL INJECTION
PublicationTransient states are an important part of the spectrum of engine loads, especially the traction engines. In the case of marine diesel engines, transient states are of particular importance in reducing the analysis of motion units for special areas and maneuvering in port, the participation of transient states in the load spectrum significantly increases, also, the emission of toxic compounds from this period increases proportionally....
-
Sensorless Control of Polyphase Induction Machines
PublicationThe basics of transformations of polyphase systems into orthogonal systems are explained. Vector models of induction machines in orthogonal planes are analysed and multiscalar models for rotor flux and main flux together with stator current are presented. A speed observer based on an extended model of the induction machine for selected variables is applied in the control system for the induction machine. On the basis of the model...
-
On extending open source IMS platform for integrated IPTV and VoIP services over IPv6
PublicationEven when IMS is the most popular platform for multimedia services, the open versions of IMS ecosystem are lacking in specified functionalities for IPTVv6 and VoIPv6 services. In this paper, we extend current client and server open source software in order to provide reliability and security to these multimedia services. As a part of our work the IMS architecture for conferencing system with proposed mechanisms to improve system...
-
Models of Structures in Didactics
PublicationThe final aim of teaching students subjects, such as structural mechanics, reinforced concrete, and steel structures is to teach them how structures work in a given building as well as to provide them with skills enabling them to calculate and design structures. The behavioral model of the structure, contrary to the architectural model, which focuses mainly on the external form of the building, shows workings from both the static...
-
Numerical Simulations of Hydrodynamic Open-Water Characteristics of a Ship Propeller
PublicationThe paper presents the results of numerical simulations of ship propeller operation bearing the name of Propeller Open Water (POW) Tests. The object of tests was a sample ship propeller (PPTC1), the geometrical and kinematic data of which are available, along with the results of model tests, on the official page of the research centre involved in the measurements. The research aimed at verifying the correctness of results of numerical...
-
An isogeometric finite element formulation for geometrically exact Timoshenko beams with extensible directors
PublicationAn isogeometric finite element formulation for geometrically and materially nonlinear Timoshenko beams is presented, which incorporates in-plane deformation of the cross-section described by two extensible director vectors. Since those directors belong to the space R3, a configuration can be additively updated. The developed formulation allows direct application of nonlinear three-dimensional constitutive equations without zero...
-
Testing of the longest span soil-steel bridge in Europe – new quality in measurements
PublicationThe article describes interdisciplinary and comprehensive diagnostic tests of final bridge inspection and acceptance proposed for a soil – steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure response was collected. The load test design was based on the nonlinear numerical simulations performed by...
-
Photogrammetric and total station's measurement of compressed column's model
PublicationModelling studies continue to play an important role. One of such study is stress determination in the reinforcement bars of reinforced columns and determine column's axis deformation. The article presents measurements results of control points located on the model of reinforced concrete column. The column was compressed in few series till it's destruction. In this studies, photogrammetric method and total station measurements...
-
Fate and significance of phthalates and bisphenol A in liquid by-products generated during municipal solid waste mechanical-biological pre-treatment and disposal
PublicationSamples of liquid by-products generated by municipal solid waste plants (MSWPs) were tested for the presence of phthalates (PAEs) and bisphenol A (BPA). The results indicated that the wastewater generated during mechanical (sorting unit - SU) and biological (composting unit - CU) pre-treatment (MBT) of residual (mixed) solid waste is a significant source of these compounds. The concentrations of PAEs (up to 32222 lg/L) and BPA...
-
Non-Destructive Diagnostics of Concrete Beams Strengthened with Steel Plates Using Modal Analysis and Wavelet Transform
PublicationExternally bonded reinforcements are commonly and widely used in civil engineering objects made of concrete to increase the structure load capacity or to minimize the negative effects of long-term operation and possible defects. The quality of adhesive bonding between a strengthened structure and steel or composite elements is essential for effective reinforcement; therefore, there is a need for non-destructive diagnostics of adhesive...
-
Active Power Quality Controllers
PublicationDynamic Static Synchronous Compensator is the most important controller for distribution networks and probably in SEEN. It has been widely used since the 1990s to regulate system voltage precisely, improve voltage profile, reduce voltage harmonics, reduce transient voltage disturbances and load compensation. Rather than using conventional capacitors and inductors combined with fast switches, the D-STATCOM uses a power-electronics...
-
Original footbridge in Mikolajki, Poland
PublicationIn summer 2016, a new footbridge in the town of Mikołajki (Poland) was built, over a stream connecting two adjacent lakes – Talty and Mikołajki. Its modern construction, based on the shape of a DN ice-boat, makes it inique in Poland, and probably in the world as well. This novel and dynamic shape became a significant landmark associated not only with Mikołajki, but also with the whole region of Mazury, as well as with sailing...
-
Debonding Size Estimation in Reinforced Concrete Beams Using Guided Wave-Based Method
PublicationThe following paper presents the results of the theoretical and experimental analysis of the influence of debonding size on guided wave propagation in reinforced concrete beams. The main aim of the paper is a development of a novel, baseline-free method for determining the total area of debonding between steel rebar embedded in a concrete cover on the basis of the average wave velocity or the time of flight. The correctness of...
-
NON-LINEAR MASTIC CHARACTERISTICS BASED ON THE MODIFIED MSCR (MULTIPLE STRESS CREEP RECOVERY) TEST
PublicationMastic containing asphalt in its composition is an example of a viscoelastic material. It is an effective binder in asphalt. It consists of a filler (<0.063 mm) and asphalt mixed in the right proportions. Just like in asphalt, its response depends on the temperature level, the load and stress time. Changing the stress stiffness of the mastic affects the non-linear course of the stress-strain relationship. Modelling of the non-linear...
-
Bilateral multi-issue negotiation of execution contexts by proactive document agents
PublicationA proactive document can react to its actual environment by autonomously selecting and performing actions integrated into its body and interact with its user. When migrating over a network of execution devices it may encounter diverse execution contexts, each one set up according to temporal characteristics of a receiving device and preferences of its owner. A concept to augment proactive documents with negotiation capability is...
-
Treatment of landfill leachate in a constructed free water surface wetland system over a decade – Identification of disturbance in process behaviour and removal of eutrophying substances and organic material
PublicationAn 8 ha free water surface wetland system in Örebro, Sweden, which has sediment traps followed by 10 ponds for treatment of landfill leachate in the methanogenic stage, was studied from 2003 to 2012. The wetland was irregularly loaded and the leachate characteristics showed high temporal and spatial variability, so Multivariate Statistical Process Control was chosen as the diagnostic tool for detecting anomalies prior to assessing...
-
THE CONCEPT OF MODELING OF SNOW IMPACT ON THE STRUCTURE OF THE SUSPENDED TAURON ARENA ROOF IN CRACOW
PublicationThe article presents studies and numerical simulations on modeling snow influence on TAURON ARENA suspended roof structure in Cracow. The scope of work includes experimental tests, functions solutions taking into account various cases of snow impact according to PN and EC, as well as numerical simulations for the sport and entertainment arena in the Czyzyny district. The FEM roof structure model developed in the SOFISITK software...
-
Research on the effect of low-sulphur marine fuels on the dynamic characteristics of a CI engine
PublicationThe implementation of low-sulphur, so-called modified marine fuels into operation requires prior labora- tory engine tests to assess the energy, emission and structural effects of their usage. This type of research are carried out on the test bed of a diesel engine as a small-scale physical model that reproduces the adequate design and process (parametric) features of a full-size marine engine. Their key stage is to determine the energy...
-
Charakterystyka odcieków powstających w aspekcie wyboru metody ich oczyszcania
PublicationArtykuł obejmuje analizę odcieków generowanych w zakładach utylizacji odpadów w aspekcie ich ilości i jakości oraz możliwości oczyszczania/zagospodarowania, ze szczególnym zwróceniem uwagi na metody biologiczne, najbardziej przyjaznej środowisku. Ponad trzyletnie badania prowadzono na dwóch obiektach zlokalizowanych w woj. pomorskim, gdzie pobierano próbki ścieków technologicznych, powstających podczas sortownia oraz kompostownia odpadów...
-
ZAPEWNIENIE SYNCHORNIZACJI CZASU PRZY CZĘŚCIOWYM WSPARCIU SIECI
PublicationCelem badań zaprezentowanych w artykule było sprawdzenie czy możliwe jest zapewnienie dużej dokładności synchronizacji czasu przy częściowym wsparciu sieci w oparciu o model HRM-1 składający się z 12 szeregowo podłączonych urządzeń sieciowych wraz z wygenerowanym ruchem sieciowym. Badania wykazały, że dla obecnie stosowanych technologii mobilnych takich jak LTE TDD możliwe jest zapewnienie odpowiedniej jakości synchronizacji czasu....
-
Ocena sprawności cyklu roboczego Pojazdu do Usuwania Odpadów z Pojemników na podstawie danych eksploatacyjnych
PublicationW artykule przedstawiona została metoda oceny sprawności cyklu roboczego śmieciarki. Wykorzystując dane eksploatacyjne wyznaczono dwa reprezentatywne cykle i na ich podstawie obliczono zarówno sprawność całego cyklu, jak i jego poszczególnych faz. Porównano wartości energii potrzebnej do opróżniania pojemników, energii do zagęszczania odpadów oraz energii z paliwa. Przedstawiono przebiegi mierzonych i obliczonych wartości w czasie...
-
Optymalizacja zasobów chmury obliczeniowej z wykorzystaniem inteligentnych agentów w zdalnym nauczaniu
PublicationRozprawa dotyczy optymalizacji zasobów chmury obliczeniowej, w której zastosowano inteligentne agenty w zdalnym nauczaniu. Zagadnienie jest istotne w edukacji, gdzie wykorzystuje się nowoczesne technologie, takie jak Internet Rzeczy, rozszerzoną i wirtualną rzeczywistość oraz deep learning w środowisku chmury obliczeniowej. Zagadnienie jest istotne również w sytuacji, gdy pandemia wymusza stosowanie zdalnego nauczania na dużą skalę...
-
Modal analysis of a steel grandstand
PublicationAmong the issues related to the idea of sustainable society is the safety of civil engineering structures devoted to satisfy different needs of people. One of the types of structures devoted to satisfy recreational needs are grandstands, which are used during sport events or music concerts. It is obligatory to consider interaction between structure and crowd load especially when the crowd movement involves rhythmic jumping, dancing,...
-
How to provide fair service for V2I communications in VANETs?
PublicationIn this paper, we focus on fairness issues of Vehicle-to-Infrastructure (V2I) communications. In particular, we show that under a common technique of selection of RSUs by OBUs based on the received signal strength, a vast variability of a number of OBUs connected to RSUs can be observed leading to inefficient/unfair service provided by RSUs. To overcome this problem, we propose an algorithm for RSU selection called RSEL to obtain...
-
Impact of trajectory simplification methods on modeling carbon dioxide emissions from ships
PublicationModels of ship fuel consumption and emissions play an essential role in estimating global shipping’s greenhouse gas emissions. They are also widely used for verification of reported CO2 emissions for systems like EU MRV (Monitoring, Reporting and Verification) or IMO DCS (Data Collection System). Such models achieve high accuracy using historical spatiotemporal information about each ship from AIS data. However, this approach requires substantial...
-
The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2 Nanocomposites
PublicationSeries ofWO3/TiO2 nanocompositeswere obtained by hydrothermal method followed by calcination in the temperature range from 400∘C to 900∘C. The characteristics of photocatalysts by X-ray diffractometry (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) showed that increasing the calcination temperature from 400 to 900∘C resulted in change of photocatalytic activity under UV-Vis light.Moreover,...
-
Call Processing Performance in a Multidomain IMS/NGN with Asymmetric Traffic
PublicationIn this paper we continue our research using the previously proposed analytical traffic model of a multidomain Next Generation Network (NGN), which is standardized for delivering multimedia services based on the IP Multimedia Subsystem (IMS). The aim of the model is to assess mean Call Set-up Delay (CSD) and mean Call Disengagement Delay (CDD), which are standardized call processing performance parameters. The output variables...
-
Magnetic Field Generated by Short Circuit Current in the 110 kV Power System
PublicationElectric fields within tissues induced by magnetic fields including transients or short-term peaks should not be time averaged and be regarded as instantaneous values as established in the ICNIRP (International Commission on Non - Ionizing Radiation Protection) guidelines. Measurements of power lines magnetic fields with regard to human beings exposure are carried out typically with maximum current load at current balance condition...