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Search results for: DAMAGE%20IDENTIFICATION
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Comparison of Oxidative Stress/DNA Damage in Semen and Blood of Fertile and Infertile Men
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Damage detection of a T-shaped panel by wave propagation analysis in the plane stress
PublicationW pracy zaprezentowano podejście obliczeniowe do analizy propagacji fal w płaskim stanie naprężenia. Problem brzegowo-początkowy podlega przestrzennej aproksymacji z użyciem wielowęzłowych, izoparametrycznych, czworobocznych elementów klasy C0. Macierze elementowe są całkowane numerycznie za pomocą kwadratury Gauss-Legendre-Lobatto. Aproksymację w dziedzinie czasu wykonano za pomocą algorytmu Newmarka. Symulacje numeryczne przeprowadzono...
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Modelling of continuum damage for application in elasto-viscoplastic Bodner-Partom constitutive equations
PublicationW artykule zaproponowano zastosowanie modelu zniszczenia Lemaitre w sprężysto-lepkoplastycznym modelu Bodnera-Partoma. Opisane podejście jest wprowadzone do programu MSC.Marc z wykorzystaniem podprocedury UVSCPL. Przedstawiono wyniki analiz numerycznych potwierdzających przyjęte założenia.
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Influence of statistical errors on damage detection based on structuralflexibility and mode shape curvature
PublicationDamage detection procedures based on measured natural frequencies and building structure mode shapes are discussed in this paper. Modal curvature and structural flexibility approaches are tested. Attention is paid to the modal identification errors that influence damage detection. This problem is studied using a computer simulation of a simple supported beam. For practical cases, the peak picking methodand its statistical errors...
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Rivaroxaban protects from the oxysterol-induced damage and inflammatory activation of the vascular endothelium
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The sources of contamination and reasons of damage of the flow part of the marine turbine engine in operation
PublicationThe aim of this paperis to show particular sensitivity of the flow part of the marine turbine engine to the presence of contaminations in the intake air. The contaminations form hard-to-remove deposits in the intervene channels that result in a reduced efficiency and performance of the engine. The paper classifies the contaminants according the source of their formation and their destructive force. The performed analyses and syntheses...
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Risk characterisation of the required index R in the new probabilistic rules for damage stability
PublicationWymagany wskaźnik podziału grodziowego R jest miarą bezpieczeństwa statku w wypadku kolizji. Zwykle wyznacza się go w oparciu o wskaźniki dla wybranych, istniejących statków. W pracy podano jak ustalić ten wskaźnik w oparciu o dane dotyczące kolizji (wypadkowości) statków.
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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...
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Assessment of damage causes of a 17 m long wind turbine blade model
PublicationThe subject matter is to verify the stiffness of the steel supporting structure and assess the causes of cracks in the 17 m long wind turbine blade model
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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...
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Damage Detection Strategies in Structural Health Monitoring of Overhead Power Transmission System
PublicationOverhead power transmission lines, their supporting towers, insulators and other elements create a highly distributed system that is vulnerable to damage. Typical damage scenarios cover cracking of foundation, breakage of insulators, loosening of rivets, as well as cracking and breakage of lines. Such scenarios may result from various factors: groundings, lightning strikes, floods, earthquakes, aeolian vibrations, conductors galloping,...
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Experimental study on the effectiveness of polymer damper in damage reduction of temporary steel grandstand
PublicationA large number of accidents, involving collapses of temporary grandstands during different types of events, were observed in the past. If the synchronized movement of people is tuned with the natural frequency of the affected part of the structure, resonance might occur. It may lead to severe damages of grandstands, their collapse or panic among the spectators. The aim of the paper is to assess, through preliminary experimental...
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Influence of geotechnical conditions on damage states of Gdansk Bay Coast cliff formations
PublicationA geotechnical aspect of destruction processes of seashores was identified based on the case of erosion of Gdansk Bay Coast cliff formations. Causative factors of landslide were described in the context of natural phenomena, land development and its anthropogenic transformations. Possible directions of theoretical analysis of changes in groundwater relations were indicated.
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Mechanisms of Damage to DNA Labeled with Electrophilic Nucleobases Induced by Ionizing or UV Radiation
PublicationHypoxia—a hallmark of solid tumors—makes hypoxic cells radioresistant. On the other hand, DNA, the main target of anticancer therapy, is not sensitive to the near UV photons and hydrated electrons, one of the major products of water radiolysis under hypoxic conditions. A possible way to overcome these obstacles to the efficient radio- and photodynamic therapy of cancer is to sensitize the cellular DNA to electrons and/or ultraviolet...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublicationThe paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure...
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Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
PublicationThe safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical...
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Numerical simulation of damage detection in rectangular plate by two-dimensional wavelet transform.
PublicationW pracy przedstawiono metodę lokalizacji pęknięć w płytach przy zastosowaniu transformaty falkowej.
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Gradient theories of ductile and brittle damage: a thermodynamical consistent framework and computational issues
PublicationPrzedstawiono termodynamicznie zgodny opis gradientowych teorii plastycznego i kruchego zniszczenia. Przyjęto, że propagujące mikro-zniszczenia posiadają bezwładność i ich ruch jest wywołany przez mikro-siły, które spełniają ich własne dynamiczne równania równowagi. Poza równaniami równowagi makro- i mikro-sił sformułowano pierwsze i drugie prawo termodynamiki na poziomie mikro i mezo. Zakładając ogólną formę równań konstytutywnych...
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A model of risk for assessment of ships in damaged conditions
PublicationW pracy omówiono problemy związane z modelowaniem zagrożeń, konsekwencji i ryzyka, w metodzie oceny bezpieczeństwa statków w stanie uszkodzonym. W celu dokonania oceny bezpieczeństwa statku, w metodzie zastosowano podejścia oparte na ocenie zachowania się statku i ocenie ryzyka. Podejście oparte na ocenie zachowania się statku związane jest z oceną charakterystyk hydromechanicznych statku w stanie uszkodzonych w warunkach zbliżonych...
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Wave Propagation Modelling in Composite Plates with Damages
PublicationW pracy przedstawiono model i wyniki analizy propagacji fali spręzystej w płycie kompozytowej z uszkodzeniami.
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Evaluation of pounding effects between reinforced concrete frames subjected to far-field earthquakes in terms of damage index
PublicationIn this paper, three different damage indexes were used to detect nonlinear damages in two adjacent Reinforced Concrete (RC) structures considering pounding effects. 2-, 4- and 8-story benchmark RC Moment Resisting Frames (MRFs) were selected for this purpose with 60%, 75%, and 100% of minimum separation distance and also without any in-between separation gap. These structures were analyzed using the incremental dynamic analysis...
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Imaging of Increasing Damage in Steel Plates Using Lamb Waves and Ultrasound Computed Tomography
PublicationThis paper concerns inspection of steel plates, with particular emphasis on the assessment of in-creasing damage. Non-destructive tests were performed on four plates, one of which was un-damaged, while the remaining three had a defects in the form of circular holes with a diameter of 2, 5, and 10 cm. Guided Lamb waves were used in the research, and the image reconstruction was performed using ultrasound computed tomography. The...
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A Numerical Study on Baseline-Free Damage Detection Using Frequency Steerable Acoustic Transducers
PublicationIn structural health monitoring (SHM) a considerable amount of damage detection algorithms based on guided waves (GW) have been developed. Most of them rely on extensive transducer networks, besides preliminary reference measurements of the structures. This originated a growing demand for hardware simplification and cost reduction of the wave-based SHM methods, driving the conception of new solutions enabling both: the reduction...
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Lamb wave based structural damage detection using cointegration and fractal signal processing
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Damage Detection Using Cointegration Technique and Wavelet Analysis of the Post-Cointegrated Lamb Waves
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Cointegration and wavelet-analysis-based approach for Lamb-wave-based structural damage detection
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Machine Learning Methods in Damage Prediction of Masonry Development Exposed to the Industrial Environment of Mines
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Damage to Model DNA Fragments from Very Low-Energy (<1 eV) Electrons
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Cellular Turnover: A Potential Metabolic Rate–Driven Mechanism to Mitigate Accumulation of DNA Damage
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Formulation of spectral truss element for guided waves damage detection in spatial steel trusses
PublicationW pracy przedstawiono sformułowanie wielowęzłowego elementu spektralnego oraz odpowiedniego schematu całkowania ukierunkowanego na problem propagacji fal w kratownicach przestrzennych o dowolnej geometrii. Zaproponowane podejście nie ogranicza liczby węzłów w elemencie kratowym. Porównawcze rozwiązania numeryczne przeprowadzono dla konstrukcji idealnej (w stanie nieuszkodzonym) oraz dlakonstrukcji z miejscową nieregularnością w...
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Neuro-wavelet damage detection technique in beam, plate and shell structures with experimental validation
PublicationNiniejsza praca poświęcona jest technice diagnostyki konstrukcji bazującej na transfor-macie falkowej oraz sztucznych sieciach neuronowych (tzw. system neuro-wavelet). Zastosowanie analizy falkowej pozwala na lokalizację uszkodzeń wymagającą mini-malnej ilości danych wejściowych. W tym celu niezbędna jest tylko odpowiedź kon-strukcji pomierzona w wielu punktach. Poprawę efektywności lokalizacji zniszczeń uzyskano poprzez użycie...
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Shaking table experimental study on damage mechanism of the disconnecting switch under seismic excitation
PublicationThe efficiency of the energetic network is a very import safety issue in the region experienced by the earthquake. High voltage disconnecting switches are important elements of the energetic infrastructure used to separate electric circuits (i.e. during repairs), which should not be damaged remaining fully operational. The aim of the paper is to show the results of the shaking table experimental investigation focused on damage...
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Morphology of damage inflicted on brittle polymer in lubricated contact under cyclic static load
PublicationIn this article morphology of damage inflicted on the polymethylmethacrylate (PMMA) plate in static point lubricated contact with a ball made of five different materials under cyclic normal load has been presented. It is argued that the counterface material and lubricating film play an important role in the damage process and the extent of damage inflicted in the PMMA plate.
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Application of continuous wavelet transform in vibration based damage detection method for beams and plates
PublicationW artykule zaprezentowano metodę lokalizacji uszkodzeń w konstrukcjach belkowych i płytowych bazującą na analizie falkowej. Wyznaczono postacie drgań badanych konstrukcji. Postacie drgań konstrukcji belkowej zostały przeanalizowane jednowymiarową transfrormatą falkową. Sformułowano dwuwymiarową transformatę falkową, którą zastosowano do postaci drgań konstrukcji płytowej.
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Improved calculation of damage due creep by more accurate time to rupture data representation
PublicationReguła Robinsona (Linear Life Fraction Damage Rule) jest stosunkowo łatwa w użyciu dla różnorodnych warunków obciążenia. Z tego powodu jest ona powszechnie akceptowana i używana. Potencjalne możliwości poprawy dokładności obliczeń tą metodą daje zastosowanie specjalnych funkcji do aproksymacji wyników badań wytrzymałości czasowej. W pracy zaproponowano zastosowanie funkcji typu Spline oraz bardzo elastycznej funkcji Spline3D do...
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Melatonin as a major skin protectant: from free radical scavenging to DNA damage repair
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Oxidative stress and oxidative DNA damage is characteristic for mixed Alzheimer disease/vascular dementia
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Longitudinal study of vitamins A, E and lipid oxidative damage in human milk throughout lactation
PublicationCelem pracy było zbadanie zmian wartości całkowitego potencjału antyoksydacyjnego (TAS), stężeń witamin antyoksydacyjnych i izoprostanów (markery stresu oksydacyjnego) w siarze i mleku dojrzałym. Badaniami objęto 49 kobiet po pełno terminowej ciąży i naturalnym porodzie. Kryteria wyłączenia to czynne i bierne palenie tytoniu, ostre i przewlekłe schorzeniach oraz farmakoterapia inna niż suplementacja witamin. Próbki siary pobierano...
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Assessment of damage due to earthquake-induced pounding between the main building and the stairway tower
PublicationRaporty po trzęsieniach ziemi pokazują, iż występujące podczas wstrząsów sejsmicznych zderzenia pomiędzy sąsiednimi konstrukcjami budowlanymi, lub ich częściami, mogą prowadzić do znacznych uszkodzeń lub nawet całkowitego zniszczenia konstrukcji. Celem niniejszego artykułu jest oszacowanie zakresu i intensywności zniszczeń na skutek zderzeń pomiędzy budynkiem głównym szpitala Olive View a wolnostojącą klatką schodową podczas trzęsienia...
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Compensatory functional reorganization may precede hypertension-related brain damage and cognitive decline
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Experimental and numerical study on damage detection in an L-joint using guided wave propagation
PublicationW pracy zaprezentowano metodę wykrywania i lokalizacji uszkodzeń w konstrukcji ramowej za pomocą podłużnych i poprzecznych fal sprężystych. Przeprowadzono badania numerczyne i eksperymentalne na modelu bez uszkodzenia oraz na modelu z wsprowadzonym nacięciem. Do modelowania zastosowano metodę elementów spektralnych. W pracy przedstawiono sformułowanie nowego element spektralnego dla ram płaskich bazującego na teorii pręta Mindlina...
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Damage tests of the single shell ship fuel tank with additional elastic protective coating
PublicationWejście na mieliznę lub kolizja średniej wielkości np. kontenerowca może doprowadzić do zanieczyszczenia środowiska Morza Bałtyckiego paliwem uwolnionym z rozszczelnionych, jednoposzyciowych zbiorników dennych, a ilość tego paliwa może być znaczna. W związku z tym podjęto prace badawcze zmierzające do opracowania sposobu obniżenia ryzyka rozlewu paliwa w wypadku kolizji poprzez wprowadzenie drugiej bariery ochronnej. Idea pomysłu...
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Changes of color coordinates of biological tissue with superficial skin damage due to mechanical trauma
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Experimental and numerical study on damage detection in an L-joint using guided wave propagation
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Application of continuous wavelet transform in vibration based damage detection method for beams and plates
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Polymeric Bearings – A New Base Isolation System to Reduce Structural Damage during Earthquakes
PublicationBase isolators, like lead rubber bearings, high damping rubber bearings or friction pendulum systems are extensively used in practice in many seismically active regions to protect structures against earthquake forces. The present paper reports the results obtained from the experimental study aimed to determine the effectiveness of the Polymeric Bearings in suppressing structural vibrations during dynamic excitations and therefore...
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Complementary study with magnetic and acoustic techniques of A336 steel damage state due to creep
PublicationBadano możliwość detekcji w sposób nieniszczący zmian w mikrostrukturze stali A336 poddanej próbie pełzania. Testowano dwie magnetyczne techniki (klasyczny efekt Barkhausena i emisję magnetoakustyczną) oraz dwie nowe techniki ultradźwiękowe (pomiar współczynnika elasto-akustycznego oraz dwójłomność akustyczną). Wykazano, iż wyniki badań akustycznych są komplementarne do wyników badań magnetycznych.
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Investigation on Damage-Involved Structural Response of Colliding Steel Structures during Ground Motions
PublicationEarthquakes are the most unpredictable damaging loads which can affect civil engineering structures. Due to insufficient separation distance between adjacent structures with different dynamic properties, structural collisions may occur during ground motions. Although the research on structural pounding has recently been much advanced, the studies have mainly been conducted for concrete structures. The aim of this paper is to show...
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Dominant Pathways of Adenosyl Radical-Induced DNA Damage Revealed by QM/MM Metadynamics
PublicationBrominated nucleobases sensitize double stranded DNA to hydrated electrons, one of the dominant genotoxic species produced in hypoxic cancer cells during radiotherapy. Such radiosensitizers can therefore be administered locally to enhance treatment efficiency within the solid tumor while protecting the neighboring tissue. When a solvated electron attaches to 8-bromoadenosine, a potential sensitizer, the dissociation of bromide...
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Damage-involved response of two colliding buildings under non-uniform earthquake loading
PublicationPounding between insufficiently separated buildings, which may result in considerable damage or may even lead to the total collapse of colliding structures, has been repeatedly observed during earthquakes. Earthquake-induced collisions of buildings has been intensively studied applying various structural models. It was assumed in the analyses, however, that the seismic excitation is identical for all structural supports; whereas,...