Wyniki wyszukiwania dla: gearbox failures
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An overview of the strategies for the deammonification process start-up and recovery after accidental operational failures
PublikacjaThe deammonification process has been universally acknowledged as an energy-efficient technology for sewage disposal. In contrast with traditional biological nitrogen removal technology, the deammonification process is able to remove ammonia from wastewater with the simplest nitrogen removal process because of its advantages of lower operating expenses, no organic carbon consumption, lower biomass production, lower carbon dioxide...
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Case Studies in Engineering Failure Analysis
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Reducing the Probability of Failure in Manufacturing Equipment by Quantitative FTA Analysis
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Zniszczenie korozyjne wymiennika ciepła = Corrosion failure of a heat exchanger
PublikacjaPłytowy wymiennik ciepła ze stali 316L uległ zniszczeniu po trzech latach eksploatacji, wskutek perforacji po czyszczeniu nieodpowiednim środkiem czyszczącym.
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Excavation induced cast iron pipeline failure – a numerical study
PublikacjaNumerical study on impact of an unsecured excavation on an underground pipeline. Analysis focused on investigation of pipeline displacement generated by soil movement caused by excavation and heavy traffic. Numerical calculations and soil parameter sensitivity analysis based on Finite Element Method. Some comparisons of results with real-life failure cases.
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Impact of WDM Network Topology Characteristics on the Extent of Failure Losses
PublikacjaW artykule dokonano oceny wpływu charakterystyk topologicznych sieci na rozmiar strat po awarii węzła/łącza będącej następstwem ataku. W tym celu wprowadzono współczynnik ATRF. Wyniki badań pokazały, że wykorzystanie standardowej metryki odległości do wyznaczania tras podstawowych prowadzi do istotnego zwiększenia liczby połączeń uszkodzonych w wyniku ataku w porównaniu ze skutkami awarii losowej.
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Experimental study on ultrasonic monitoring of splitting failure in reinforced concrete
PublikacjaThis paper investigates inspection of reinforced concrete elements sensitive to the splitting failure. The behaviour of a reinforced concrete specimen subjected to a tensile stress is considered. The damage detection procedure is based on the ultrasonic wave propagation technique. The piezoelectric transducers are located on both ends of the specimen and the measurements are taken periodically during the incrementally increased...
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FAILURE OF MAGNETIC FLUID SEALS OPERATING IN WATER: PRELIMINARY CONCLUSIONS
PublikacjaThe article analyses properties of magnetic fluid seals installed in rotary sealing no des which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals expo sed to long - term utility water loads, at different water pressures and shaft revolutions....
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Failure analysis of the exhaust valve face in diesel marine engine
PublikacjaThe exhaust valve from marine diesel engine which was damaged after 2000 hours of service was investigated. In order to prolong the service time the valve face was cladded with cobalt base alloy using laser technique. After failure microstructural and chemical analyses reviled that cladding process was conducted improperly. The chemical composition of the clad layer was far from the designed one and what more completely inhomogeneous....
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Fundamental Schemes to Determine Disjoint Paths for Multiple Failure Scenarios
PublikacjaDisjoint path routing approaches can be used to cope with multiple failure scenarios. This can be achieved using a set of k (k> 2) link- (or node-) disjoint path pairs (in single-cost and multi-cost networks). Alternatively, if Shared Risk Link Groups (SRLGs) information is available, the calculation of an SRLG-disjoint path pair (or of a set of such paths) can protect a connection against the joint failure of the set of links...
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Analysis of Failure Mechanism in Joints with Positive Eccentricity in CFS Truss
PublikacjaThe paper presents studies concerning the load-bearing capacity of truss joints with a positive eccentricity resulting from the arrangement of geometric members and the failure mechanisms observed in the joints. Based on the previously conducted experimental study, a numerical model of the tested fragment of the CFS truss with eccentricity in the joint was created and validated. All structural details of the tested truss and the...
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Assessment of unusual failure in crankshaft of heavy-duty truck engine
PublikacjaThe unusual premature failure of a heavy-duty truck engine crankshaft has been the subject of a rigorous study, and this manuscript describes it in detail. The failure was happened to begin with the growth of the crack from the surface defects, in the form of the clusters of non-metallic inclusions, in the lubrication hole zone of the first main journal, which was the stress concentration zone. A series of experiments including...
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RECODIS: Resilient Communication Services Protecting End-user Applications from Disaster-based Failures
PublikacjaDisaster-based failures can seriously disrupt any communication network, making its services unavailable. Such disruptions may be caused by natural disasters, technology-related failures, or malicious attacks, and they are observably increasing in number, intensity and scale. When network services that are a part of critical infrastructure become unavailable, commercial and/or societal problems are inevitable. The issue of limiting...
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The PARAGON Heart Failure trial – ongoing investigation of the angiotensin receptor antagonist/neprilysin inhibitor sacubitril/valsartan in heart failure patients with hypertension and preserved ejection fraction
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Sympathetic Activation in Chronic Heart Failure: Potential Benefits of Interventional Therapies
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Enhanced Sympathetic and Ventilatory Responses to Central Chemoreflex Activation in Heart Failure
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Prefabricated structures under earthquake excitation: damage and failure of connection joints
PublikacjaCelem artykułu jest analiza zachowania się złączy pomiędzy elementami belkowymi a słupami w konstrukcjach prefabrykowanych poddanych obciążeniom dynamicznym powstającym podczas trzęsień ziemi. Wyniki przedstawione w pracy, uzyskane na podstawie badań numerycznych przeprowadzonych dla wybranego modelu konstrukcji, pokazują, iż złącza są najsłabszym elementem wymagającym zwrócenia szczególnej uwagi przy projektowaniu konstrukcji...
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Predictive Factors of Late Venous Aortocoronary Graft Failure: Ultrastructural Studies
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Computer aided failure modes and effect analysis of safety related controlsystem
PublikacjaW artykule przedstawiamy problem związany z podniesieniem bezpieczeństwa funkcjonalnego elementów wykonawczych na przykładzie zaworu regulacyjnego. Jest to istotne z punktu widzenia pracy całego układu, ponieważ elementy wykonawcze decydują o wypełnieniu misji związanej z produkcją lub bezpieczeństwem. Stosowanie analizy FMECA na etapie projektowania umożliwia wyznaczenie krytycznych uszkodzeń z całego ich zbioru oraz określenie...
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Acute renal failure due to leptospirosis. Diagnostic challenges – a case report
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Lamb wave-based monitoring of shear failure of an adhesive lap joint
PublikacjaThe paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals...
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Failure model of main elements of the ship engine crankshaft-piston assembly
PublikacjaThe paper presents a failure model of main elements of the crankshaft-piston assembly, based on failures ofcrankshaft-piston assembly and timing gear system of the Sulzer RD engines, retrieved from the equipment reliabilitydata of selected ships.
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Failure of austenitic stainless steel tubes during steam generator operation
PublikacjaThe article presents the failure process of austenitic stainless steels used in power devices, such as heat exchangers, steam generators, in terms of local corrosion: pitting, stress and intergranular corrosion, paying particular attention to welded joints area. The effect of steel chemical composition, microstructure, welding process and work environment was analyzed. The second part of the article presents the results of the...
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Thermal failure of a second rotor stage in heavy duty gas turbine
PublikacjaThe impulse mode of operation and the supply of various types of fuels causes frequent failures even in the heavy duty gas turbines. The paper presents the ravages of second rotor stage failure in a gas turbine. The excessive thermal elongation rise caused by fuel change was indicated as the main cause. We applied nonlinear numerical analysis, preceded by thermodynamic calculations of the turbine and visual inspection of the effects...
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In-plane shear nonlinearity in failure behavior of angle-ply laminated shells
PublikacjaThe paper concerns the progressive failure analysis of laminates with the in-plane shear nonlinearity accounted for.The nonlinear shear response of the layer is described by the constitutive relation treating the stresses as a function of strains. Thus it can be easily incorporated into the displacement-based FEM codes. The brittle failure mechanisms of the fibers and the matrix of the layer are recognized with the use of the Hashin...
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Tensile validation tests with failure criteria comparison for various GFRP laminates
PublikacjaThe paper studies the mechanical properties of glass fibre reinforced polymers (GFRP) with various types and orientation of reinforcement. Analyzed specimens manufactured in the infusion process are made of polymer vinyl ester resin reinforced with glass fibres. Several samples were examined containing different plies and various fibres orientation [0, 90] or [+45, –45]. To assess the mechanical parameters of laminates, a series...
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Examining Ownership Equity as a Psychological Factor on Tourism Business Failure Forecasting
PublikacjaThis paper examines ownership equity as a predictor of future business failure within the tourism and hospitality sectors. The main goals of this study were to examine which ratios are the most important for a tourism business failure forecasting model and how significant is the “total percentage of equity ownership by company directors” ratio compared with other ratios associated with the probability of bankruptcy. A stepwise...
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Echocardiographic correlates of dyspnoea during acute decompensated heart failure treatment
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Evaluation of strength, deformability and failure mode of composite structural insulated panels
PublikacjaW pracy przedstawiono wyniki badań wytrzymałościowych na zginanie i ściskanie paneli kompozytowych CSIP. Panele składają się z 2 sztywnych okładzin cementowo-magnezjowych zbrojonych włóknem szklanym oraz miękkiego rdzenia ze styropianu. Panele charakteryzują się m.in. niskim ciężarem, szybkim i łatwym montażem oraz wysoką wytrzymałością, ognioodpornością, odpornością na korozję i izolacyjnością cieplną.
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Figures de la Psychanalyse
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Failures and a concept of corrosion protection system for spiral classifiers at KGHM Polska Miedź S.A. Ore Concentration Plant
PublikacjaThe Ore Concentration Plant, where the process of flotation is carried out as well as the final production of copper concentrate, plays a key role in the entire production line of KGHM Polska Miedź S.A. Majority of operations related to the run-of-mine preparation to copper flotation enrichment are carried out in a water environment. The maintaining of production process continuity requires to pursue minimisation of many production...
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Turning maneuver as a potential cause of the next stability failure mode for a ship in operation
PublikacjaThe only formal stability-related requirement referring to a turning maneuver of a ship results from the IS Codeand its application is limited to passenger ships only. The goal of the adopted criterion is to prevent an excessiveangle of heel in turn. Likewise, the remaining prescriptive criteria, this one is simply based on the concept ofa threshold that must not be exceeded. In this case, the angle of heel...
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Fault Tree Analysis and Failure Diagnosis of Marine Diesel Engine Turbocharger System
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Failure analysis and modernization of high-pressure hydraulic press for drilling tubes testing
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The Effects of Wastewater Treatment Plant Failure on the Gulf of Gdansk (Southern Baltic Sea)
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Failure of cold-formed beam: How does residual stress affect stability?
PublikacjaIn machine industry, stresses are often calculated using simple linear FEM analysis. Occasional failures of elements designed in such a way require recomputation by means of more sophisticated methods, eg. including plasticity and non-linear effects. It usually leads to investigation of failure causes and improvement of an element in order to prevent its unwanted behavior in the future. The study presents the case where both linear...
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Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
PublikacjaThe paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...
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FEM analysis of composite materials failure in nonlinear six field shell theory
PublikacjaThe monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...
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Risk of power cables insulation failure due to the thermal effect of solar radiation
PublikacjaLow-voltage, as well as high-voltage power cable lines, are usually buried in the ground. The ampacity of the power cables in the ground mainly depends on the thermal resistivity of the soil, which may vary in a wide range. A common practice in power cable systems performance is to supply them from a pole of an overhead line. If so, a section of the line is located in free air and can be directly exposed to solar radiation. In...
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Combined thrust radial bearing of a submarine main shaft – Design and analysis of failure
PublikacjaThis paper presents an analysis of the combined thrust radial bearing of a submarine propulsion shaft. The lubrication system of the bearing is based on a fixed ring. The efficiency of the lubrication system depends on the shaft speed and temperature, which affects oil viscosity. In turn, the thrust bearing load also depends on the rotational speed of the shaft, because as the speed increases, the drag of the ship increases simultaneously,...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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Failure mode prediction for composite structural insulated panels with MgO board facings
PublikacjaSandwich panels are readily used in civil engineering due to their high strength to weight ratio and the ease and speed of assembly. The idea of a sandwich section is to combine thin and durable facings with a light-weight core and the choice of materials used allows obtaining the desired behaviour. Panels in consideration consist of MgO (magnesium oxide) board facings and expanded polystyrene core and are characterized by immunity...
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FE-analysis of failure behaviour of reinforced concrete columns under eccentric compression
PublikacjaArtykuł omawia obliczanie słupów żelbetowych poddanych ściskaniu mimośrodowemu z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano przy zastosowaniu MES i sprężysto-plastycznego prawa konstytutywnego rozszerzonego o długość charakterystyczną mikrostruktury za pomocą teorii nielokalnej.
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The Influence of the Soil Environment on the Corrosivity of Failure Infrastructure - Case Study of the Exemplary Water Network
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Numerical investigation of flooding of real-topography developed areas following river embankment failure
PublikacjaPrzedstawiono numeryczne symulacje hydrodynamiki przepływu powodziowego na terenie zabudowanym po przerwaniu wału przeciwpowodziowego. Zaprezentowano porównanie obliczeń z wynikami własnych pomiarów laboratoryjnych przeprowadzonych w Laboratorium Hydrauliki Inżynierii Środowiska Politechniki Gdańskiej.Zaproponowano wykorzystanie modelu przepływu do oceny zagrożenia powodziowego obszarów zabudowanych zlokalizowanych na terenach...
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Fulminant hepatic failure in woman with iron and non-steroidal anti-inflammatory drug intoxication
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An advanced tool integrating failure and sensitivity analysis into novel modeling of the stormwater flood volume
PublikacjaAn innovative tool for modeling the specific flood volume was presented that can be applied to assess the need for stormwater network modernization as well as for advanced flood risk assessment. Field measurements for a catchment area in Kielce, Poland, were used to apply the model and demonstrate its usefulness. This model extends the capability of recently developed statistical and machine learning hydrodynamic models developed...
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A machine learning approach to classifying New York Heart Association (NYHA) heart failure
PublikacjaAccording to the European Society of Cardiology, globally the number of patients with heart failure nearly doubled from 33.5 million in 1990 to 64.3 million in 2017, and is further projected to increase dramatically in this decade, still remaining a leading cause of morbidity and mortality. One of the most frequently applied heart failure classification systems that physicians use is the New York Heart Association (NYHA) Functional...
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Application of Hydrodynamics Model for a Case Study of the Kolbudy II Reservoir Embankment Hypothetical Failure
PublikacjaW pracy przedstawiono hydrodynamiczny model przepływu powodziowego. Jako przykład symulacji powodzi zaprezentowano hipotetyczną awarię bocznej zapory zbiornika Kolbudy II przy Elektrowni Wodnej Bielkowo. Celem symulacji było późniejsze wyznaczenie zasięgu strefy zagrożenia powodziowego wywołanego potencjalną awarią obwałowania zbiornika.
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Modes of Failure Analysis in Reinforced Concrete Beam Using Laser Scanning and Synchro-Photogrammetry
PublikacjaThe following paper reveal the limitations and possibilities of terrestrial laser scanning technology adaptation in diagnostics of reinforced concrete beams. In this paper, authors present potential spectrum of TLS use in modes of failure analysis of R-C beams and determines under which conditions the laser technologies might be applied. Research was carried out at the Regional Laboratory of Structural Engineering at Gdansk University...