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Search results for: KOLUMNY Z WYPEŁNIENIEM STYREN-DIWINYLOBENZEN (SDVB)
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Torsional buckling and post-buckling of columns made of aluminium alloy
PublicationThe paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation...
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Flexural buckling and post-buckling of columns made of aluminium alloy
PublicationThe paper concerns flexural buckling and initial post-buckling of axially compressed columns made of aluminium alloy described by the Ramberg-Osgood relationship. The non-linear differential equation of the problem is derived using the stationary total energy principle and the assumptions of classical beam theory within a finite range. The approximate analytical solution of the equation leading to the buckling loads and initial...
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Investigation of natural frequencies of axially loaded thin-walled columns
PublicationThe paper deals with correlation between natural frequencies of two steel thin-walled columns and the corresponding applied load. The structures are made of cold-formed lipped channel sections. The columns lengths were assumed to follow two buckling patterns – global flexural and flexural-torsional buckling. In the thicker structure two material models were considered – linearly-elastic and elastic-perfectly plastic. Numerical...
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Effect of initial imperfection on buckling of thin-walled I columns
PublicationEffects of initial geometrical imperfections on critical buckling loads of thin-walled I columns are investigated. Torsional and flexural buckling are taken into account. The column behaviour is described in accord to the theory of thin-walled beams with nondeformable cross-section. Some numerical examples and conclusions related to effects of imperfections on properties of the critical loads are presented.
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Buckling of thin-walled columns accounting for initial geometrical imperfections
PublicationThe paper is devoted to the effect of some geometrical imperfections on the critical buckling load of axially compressed thin-walled I-columns. The analytical formulas for the critical torsional and flexural buckling loads accounting for the initial curvature of the column axis or the twist angle respectively are derived. The classical assumptions of theory of thin-walled beams with non-deformable cross-sections are adopted. The...
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The experimental research on RC columns, loaded at sign-variable eccentricity
PublicationThe research focuses on testing the behaviour of the reinforced concrete columns compressed at a variable eccentricity. The fact of possible variable eccentricity in compressed columns is not considered in the current calculation procedures. The objective of the research was to examine whether indeed the load history has no impact and whether the reinforced concrete columns compressed at eccentric of variable sign could be analysed...
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A Comparison of the Exergy Efficiencies of Various Heat-Integrated Distillation Columns
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Sensitivity analysis of flexural and torsional buckling loads of laminated columns
PublicationThe paper concerns first order sensitivity analysis of flexural and torsional bucklin g loads of axiallycompressed thin-walled columns with bisymmetric or axisymmetric cross-section made of unidirectional fibre-reinforcedlaminate. The first variation of critical loads versus some variations of the column material properties and cross-sectionaldimensions is derived. Numerical examples dealing with simply supported I-columns are...
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Incorporating installation effects into the probability analysis of controlled modulus columns
PublicationThis technical report presents the probabilistic analysis which integrates the Monte Carlo simulation (MCS) with random field theory to model the load–displacement behavior of Controlled Modulus Columns (CMCs) in overconsolidated Poznań clay. Presented study focuses on the practical aspects of statistical analysis of geotechnical data, numerical model development, and results evaluation. Variability and spatial distribution of...
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Stability analyses of a cylindrical steel silo with corrugated sheets and columns
PublicationW artykule przedstawiono wyniki obliczeń stateczności silosów z blachy falistej ze słupami. Wykonano analizy linowe i analizy nieliniowe stosując metody elementów skończonych. W obliczeniach uwzględniono model przestrzenny powłokowy oraz uproszczony model przestrzenny z blachy ortotropowej z belkami. Wyniki numeryczne porównano z Eurokodem.
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Poli(estro-eterouretany) zsyntezowane z nienasyconych oligo(alkilenoestro-etero)dioli i 4,4'-diizocyjanianu difenylometanu sieciowane styrenem, akrylanem butylu lub 2,4,6-triallyloksy-1,3,5-triazyną
PublicationPrzedstawiono wyniki badań dotyczące syntezy, budowy i właściwości nienasyconych oligo(alkilenoestro-etero)dioli (OAEE), jako półproduktów do otrzymywania nienasyconych prepolimerów estro-eterouretanowych oraz omówiono rezultaty eksperymentów dotyczących syntezy i właściwości usieciowanych poli(estro-eterouretanów) a także opisano otrzymywanie i właściwości kompozytów poli(estro-eterouretanowo)-szklanych.
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Ekspertyza techniczna dotycząca wpływu drgań na kolumny betonowe wykonywane w ramach budowy drogi ekspresowej S19 Lubartów-Kraśnik
PublicationCelem ekspertyzy było określenie wpływu drgań generowanych w trakcie wytwarzania nowej kolumny betonowej na już istniejące, które zostały wykonane wcześniej.
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Introduction in to tyre simulations
PublicationW artykule przedstawiono wyniki symulacji komputerowej zachowania się opony w czasie badania jej oporów toczenia w oparciu o program LMS Virtual Lab. Przedstawiono także wnioski wynikające z przeprowadzonej symulacji.
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Testy terenowe prototypowego świdra DPDT do formowania pali i kolumn przemieszczeniowych wkręcanych
PublicationPrzedstawienie prototypowej konstrukcji świdra do wykonywania pali i kolumn przemieszczeniowych wkręcanych. Analiza porównawcza wyników testów terenowych oporów wkręcania świdrów DPDT i SDP. Wnioski na temat efektywności działania i zasadności stosowania nowej konstrukcji świdra w praktyce wykonawczej.
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Online stores' credibility: the moderating role of customers' gender and self-efficacy
PublicationThe evaluation of online stores’ credibility by customers in regard of gender and self-efficacy is presented. Two groups of attributes, usability and informational content, were characteristics of credibility. The survey involved students as representatives of the largest group of the Internet users. As shown by the results obtained, the informational content of online stores (such as recommendations) and its professionalism was...
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Assessment of absorbability of seamless flux cored wires stored in extreme conditions
PublicationWater absorption tests by gravimetric method of three specimens of seamless rutile flux cored wires for flux cored arc welding were carried out. Examined wires are characterized by varied absorbability (Wg is ranged from 0.03 to 0.11% after 200 h of moisturizing).
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Pounding between Inelastic Three-Storey Buildings under Seismic Excitations
PublicationStructural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations....
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Three-dimensional mapping for data collected using variable stereo baseline
PublicationThe paper describes a system of 3D mapping of data collected with due regard for variable baseline. This solution constitute an extension to a VisRobot sub-system developed as a subsystem, necessary for implementing the generic idea of using mobile robots to explore an indoor static environment. This subsystem is to acquire stereo images, calculate the depth in the images and construct the sought 3D map. Stereo images are obtained...
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Stereo Camera Upgraded to Equal Baseline Multiple Camera Set (EBMCS)
PublicationThe paper presents the results of using a set of five cameras called Equal Baseline Multiple Camera Set (EBMCS) for making 3D images, disparity maps and depth maps. Cameras in the set are located in the vicinity of each other and therefore the set can be used for the purpose of stereoscopy similarly as a stereo camera.EBMCS provides disparity maps and depth maps which have a better quality than these maps obtained with the use...
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Preliminary studies of seamless flux cored wires stored in extreme conditions
PublicationIn the paper preliminary experimental studies of flux cored wires moisturized under controlled conditions are described. Three seamless wires of different grades have been placed in environmental chamber and moisturized in extremely adverse conditions (temperature T = 60° C, relative humidity H = 90%) for 240 hours. During this time measurements of weight gain and observations of surface of wires have been carried out. Also diffusible...
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Mitigating Time-Constrained Stolen-Credentials Content Poisoning in an NDN Setting
PublicationNDN is a content-centric networking architecture using globally addressable information objects, created by publishers and cached by network nodes to be later accessed by subscribers. Content poisoning attacks consist in the substi-tution by an intruder publisher of bogus objects for genuine ones created by an honest publisher. With valid credentials stolen from an honest publisher, such attacks seem unstoppa-ble unless object...
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The Usage of the BP-Layers Stereo Matching Algorithm with the EBCA Camera Set
PublicationThis paper is concerned with applying a stereo matching algorithm called BP-Layers to a set of many cameras. BP Layers is designed for obtaining disparity maps from stereo cameras. The algorithm takes advantage of convolutional natural networks. This paper presents using this algorithm with a set called Equal Baseline Camera Array. This set consists of up to five cameras with one central camera and other ones aground it. Such a...
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Sposób uzyskiwania zgodności przebiegu programu elucji gradientowej w kolumnie z wymaganą postacią programu oraz zapewnienia odtwarzalności parametrów retencji na drodze korekty programu elucji.
PublicationPrzedstawiono ogólny model dynamiki mieszania cieczy w elementach gradientowego aparatu HPLC. Na podstawie wyników matematycznej i doświadczalnej analizy rozproszonej postaci modelu przedstawiono algorytm postępowania, zapewniający uzyskiwanie zgodności przebiegu programu elucji z wymaganą funkcją i wyniki doświadczalnej weryfikacji skuteczności algorytmu. Stwierdzono skuteczność opisanego sposobu postępowania.
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Dynamic mechanical properties and thermal degradation process of the compositions obtainedfrom unsaturated poly(ester urethanes) cross-linked with styrene
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Enhanced interfacial and mechanical performance of styrene-butadiene rubber/silica composites compatibilized by soybean oil derived silanized plasticization
PublicationSilanized plasticizer (SP) was chemically derived and synthesized from soybean oil (SBO) co-vulcanized with bis-(3-(triethoxysilyl)-propyl) tetrasulfide (TESPT) by using the sulfur-accelerated curing system. SP extended styrene-butadiene rubber (SBR)/silica composites have been studied for their improved filler dispersion through coupling interaction at the SBR/silica interface. The effect of SP on cross-link density, thermal,...
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Retention modeling of some saccharides separated on an amino column.
PublicationUsing an amino column (Supelcosil LC-NH2) and different mixtures of acetonitrile-water, quantitative structure-retention relationship models are discussed. These models are based on computed molecular descriptors representing numerically structured features of some saccharides. The obtained results are underlining the lipophilicity/hydrophilicity balance, and how this is controlling the separation of the saccharides. The resulting...
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Progress in used tyres management in the european union: a review
PublicationThe dynamic increase in the manufacture of rubber products, particularly those used in the automobile industry, is responsible for a vast amount of wastes, mostly in the form of used tyres, of which more than 17 million tonnes are produced globally each year. The widely differing chemical compositions and the cross-linked structures of rubber in tyres are the prime reason why they are highly resistant to biodegradation, photochemical...
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Thermogravimetric analysis/ pyrolysis of used tyres and waste rubber
PublicationThe process of pyrolysis is investigated in this paper. The pyrolysis results of two samples: waste tyres and rubber at different heating rates (10, 20, 50 K/min), were compared. In other experiments the degradation of two pyrolysis products, char and oil was examined. The kinetic study using the thermogravimetry equipment (TG) was done, which allowed determination of the kinetic mechanism of the process. The elemental analysis...
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Research on operational characteristics of tyres with run flat insert
PublicationThe paper describes results of research on heavy vehicle tyre with Run Flat VFI insert. The experiment has included the determination of heat generation, rolling resistanceand radial stifnessof two different tyre designes (textile and steel carcass). The results have been used for the purpose of ewalution of tyre operating characteristics. The study included research on non-inflated tyre properties. The purpose of the paper is...
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Nowoczesne rozwiązania stref kontaktowych ruchomych zamknięć wodnych
PublicationW pracy przedstawiono zagadnienia kontaktowe zamknięć wodnych. Szczególną uwagę zwrócono na obciążenie kontaktowe wrót, zagadnienia trybologiczne i inne czynniki występujące w stykach wrót oraz ich wpływ na całkowitą nośność zamknięć. Jednym z decydujących czynników w projektowaniu styków zamknięć jest dobór ich materiału. Przedstawiono wyniki badań laboratoryjnych wybranych materiałów stosowanych do konstrukcji styków kontaktowych....
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On some aspects of torsional buckling of thin-walled I-beam columns
PublicationW pracy podsumowano wyniki badań zjawiska wyboczenia skrętnego prętów o przekroju dwuteowym. Zbadano wpływ początkowego wygięcia giętnego na wartość siły krytycznej wyboczenia skrętnego. Z zasady stacjonarności energii potencjalnej wyprowadzono równania różniczkowe wyboczenia skrętnego. Wartość siły krytycznej wyznaczono stosując podejście perturbacyjne. Wyniki analityczne porównano z rezultatami otrzymanymi za pomocą 6-parametrowej...
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Distortional buckling of thin-walled columns of closed quadratic cross-section
PublicationThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
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COMPUTER-AIDED CONSTRUCTION AT DESIGNING REINFORCED CONCRETE COLUMNS AS PER EC
PublicationThe article presents the author’s computer program for designing and dimensioning columns in reinforced concrete structures taking into account phenomena affecting their behaviour and information referring to design as per EC. The computer program was developed with the use of C++ programming language. The program guides the user through particular dimensioning stages: from introducing basic data such as dimensions, concrete...
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The use of GFRP tubes as load-bearing jackets in concrete-composite columns
PublicationThe paper presents the fields of applications of polymer composites in building structures. The use of composite glass fibre tubes is discussed in more detail. The laboratory methods used to test the mechanical properties of these pipes are presented. An original research program is presented, including six concrete-filled glass fibre tubes. The cylinders and columns made in this way were tested for their axial load capacity. Conclusions...
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Numerical analysis on axial capacity of steel built-up battened columns
PublicationThis paper deals with the numerical analysis aimed at study the bearing capacity of pinended steel built-up columns under axial compression. Finite element (FE) models were performed for the columns presented in the literature. The main problem discussed in the article is the shape and magnitude of geometric imperfections introduced into the numerical FE model, necessary to obtain the load capacity consistent with the experimental...
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Direct design of Controlled Modulus Columns (CMC) based on in-situ testing
PublicationIn this paper, the serviceability limit state and bearing capacity of tension screw displacement piles were analyzed using the results of static pile load tests, carried out on the test plot near the Elbląg city, and field, and laboratory tests. The paper presents the methodology of determining the pile load-settlement curve using different types of t-z transfer functions. The new method of constructing the pile load-settlement...
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Dynamic mechanical properties and thermal degradation process of the compositions obtained from unsaturated poly(ester urethanes) cross-linked with styrene
PublicationW pracy przedstawiono właściwości dynamiczno-mechaniczne oraz stabilność termiczną poli(estro uretanów) sieciowanych styrenem. Badane poli(estro uretany) syntetyzowano z nienasyconych oligomeroli opartych na cis-2-buten-1,4-diolu oraz 4,4`-diizocyjanianie difenylometanu. Wyniki badań dynamicznych właściwości mechanicznych otrzymanych poliuretanów potwierdziły separację fazową uzyskanych kompozycji. W pracy przedstawiono również...
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Grzegorz Kotłowski, Elżbieta Starek, Łacińskie inskrypcje w kościołach Gdańska. Śródmieście
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Direct determination of cadaverine in the volatile fraction of aerobically stored chicken breast samples
PublicationTo supplement the currently used methods for poultry meat shelf life assessment, it might be necessary to develop a technique for rapid headspace analysis of volatiles with no prior sample preparation step. Biogenic amines, in particular cadaverine, are considered meat spoilage indicators. Described in this article are the results of a preliminary investigation of the applicability of proton transfer reaction mass spectrometry...
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Linking of adjacent three-storey buildings for mitigation of structural pounding during earthquakes
PublicationThe reports after major earthquakes indicate that the earthquake-induced pounding between insufficiently separated buildings may lead to significant damage or even total collapse of structures. An intensive study has recently been carried out on mitigation of pounding hazards so as to minimize the structural damages or prevent collisions at all. The aim of this paper is to investigate the effectiveness of the method when two adjacent...
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Elastic and inelastic multi-storey buildings under earthquake excitation with the effect of pounding
PublicationW artykule przeprowadzono analizę różnic w liniowym i nieliniowym zachowaniu się budynków wielokondygnacyjnych podczas trzęsień ziemi z uwzględnieniem efektu zderzeń pomiędzy nimi. Analizę numeryczną przeprowadzono dla różnych wartości ekstremalnych przyspieszeń gruntu. Wyniki pokazują, iż zaimplementowanie nieliniowego modelu zachowania się budowli jest bardzo istotne w celu uzyskania dokładnej odpowiedzi konstrukcji.
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Coping styles and symptomatic manifestation of first-episode psychosis: Focus on cognitive performance
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Coping Styles, Mental Health, and the COVID-19 Quarantine: A Nationwide Survey in Poland
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Mury oporowe z gruntu zbrojonego z przekładkami z keramzytu
PublicationW czerwcu 2019 r. nastąpiło otwarcie nowo budowanego wiaduktu na ulicy Drwęckiej w Ostródzie, który zastąpił jeden z trzech przejazdów kolejowo-drogowych znajdujących się w centrum miasta. Zakończenie budowy bezkolizyjnego przejazdu nad torami kolejowymi pozwoliło na bezpieczne oraz szybkie połączenie północnej i południowej części Ostródy. Zastosowanie materacy z keramzytu w konstrukcji z gruntu zbrojonego.
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Tyre dynamic radius determination
PublicationW artykule opisano stanowisko wykorzystywane do badania oporu toczenia opon samochodowych znajdujące się w Katedrze Konstrukcji Maszyn i Pojazdów Wydziału Mechanicznego Politechniki Gdańskiej. Przedstawiono wyniki badań promienia dynamicznego opony Michelin 165/80R13 83T z bieżnikiem CLASSIC przeprowadzone z wykorzystaniem tego stanowiska na nawierzchni Safety Walk 80. Badania przeprowadzono zmieniając: prędkość jazdy, obciążenie...
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Determination of the shape of the CFGFT cylindrical column based on laboratory tests
PublicationAnalyses were carried out on glass-fibre-reinforced polymer tube columns with reference to laboratory tests. The angles of the glass fibre beams were 20◦, 55◦ and 85◦. The study employed non-classical operational calculus. Various modulated harmonic signal shapes were considered for columns and tubes at buckling. The buckling loads were assessed and compared for different models.
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THE INTERACTION BETWEEN STEEL COLUMN CHORD AND CLOSELY SPACED REINFORCEMENT.
PublicationNowadays, more often than before, civil engineering designers are willing to use steel build-up members composed of single or doubled cold-formed chords interconnected using different mechanical connectors. This paper subject is an analysis of cooperation of a closely spaced built-up cold-formed chord interconnected with series of bolts that are located along the length of the member in a specific spacing. This distance along the...
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Influence of stirrups in a concrete shell on strengthening reinforced concrete column
PublicationTwelve concrete columns, with a 150x150mm square section and three columns with a circular section (d=200mm), are tested to investigate the effect of strengthening by RC jacket. Based on a confined concrete model for axial static loading, an analytical methods, reported in the literature are proposed to predict the behavior of columns with RC jacket. The results support the conception that the effect of strengthening depends...
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Oxygen accumulation rate with and without live bacteria in column bioreactors
PublicationBadano wnikanie i akumulację tlenu w reaktorach airlift z cyrkulacją zewnetrzną. Stosowano reaktory z odwrotną warstwą fluidalną w strefie opadania, warstwą fluidalną w strefie wznoszenia oraz reaktor z cyrkulującą zawiesiną. Badano wpływ prędkości przepływu powietrza oraz stężenia cząstek stałych na szybkośc akumulacji tlenu w cieczy w reaktorach nie zawierających bakterii oraz w obecności bakterii Acinetobacter calcoaceticus...
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Experimental and numerical study on deformed steel columns subjected to impact load during earthquakes
PublicationThe soft-storey failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an upper soft storey of a structure results in large impact load acting on the lower floors and if the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of the whole building. The aim of the present paper is to investigate the dynamic behaviour...