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Search results for: BLADDER
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Dynamics of cutting power during sawing with circular saw blades as an effect of wood properties changes in the cross section
PublicationIn the paper the effect of the method calculation upon the cutting power is presented. In computations were used models in which fracture toughness was incorporated. The comparison concerned models as follows: FM-CM – classic model in which the sum of all uncut chip thicknesses of the simultaneously teeth engaged represented the mean uncut chip thickness, FM-FDM – full dynamical model in which besides variable uncut chip thickness...
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Modeling by finite element methods of impact of erosion on frequency of normal modes of L-0 blade
PublicationAfter some time of exploitation steam turbine rotors blades in energetic industry they are being eroded and also their frequency of normal modes is changed. Those changes can cause to unwanted shift of blades normal mode frequencies. It is necessary to find quick method of rating changes of frequency in connection of mass loss due erosion. The evaluation of this dependence was made by finite element modeling method using HyperWorks...
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Experimental research of circular saw blade tooth axial run-out influence on cutting effects
PublicationW pracy przedstawiono metodę pomiaru i wyniki badań doświadczalnych wpływu bicia osiowego ostrzy piły tarczowej na efekty przecinania
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Damage Detection in the Wind Turbine Blade Using Root Mean Square and Experimental Modal Parameters
PublicationThe paper presents results of an experimental study related to a non-destructive diagnostic technique used for preliminary determination the location and size of delamination in composite coatings of wind turbine blades. The proposed method of damage detection is based on the analysis of the ten first mode shapes of bending vibrations, which correspond to displacements of rotor blades perpendicular to the rotor plane. Modal parameters...
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The Optimal Spindle Speed Map for Reduction of Chatter Vibration During Milling of Bow Thruster Blade
PublicationW artykule przedstwiono przykład wykorzystania procedury tworzenia mapy optymalnych prędkosci obrotowych w celu ograniczenia drgań samowzbudnych podczas frezowania płata śruby okrętowego steru strumieniowego.
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Application scanning laser measurements and wavlet transform for dmagae detection in composite wind turbine blade
PublicationW pracy przedstawiono wyniki pomiarów postaci drgań własnych kompozytowej łopaty turbiny wiatrowej. Przedstawiono wyniki detekcji uszkodzeń oparte o analize falkową zmierzonych form drgań.
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Washboarding during cutting on frame sawing machines II. Experimental study of the saw blade behaviour
PublicationPraca jest swego rodzaju suplementem do referatu przedstawianego na 15th Inernational Wood Machining Seminar w Los Angeles, CA, USA. Opisano uzyskane wyniki badań doświadczalnych prowadzonych w oparciu o plan badań Hartley`a.Czynnikami badanymi były: naprężenia napinające brzeszczotu piły, częstotliwość skoków ramy piłowej oraz wysokość cięcia przedmiotu obrabianego. Czynnikami wynikowymi były: wysokość sfalowania powierzchni oraz...
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Geometrical conditions of saw blade`s entering into and going out of material during wood cutting
PublicationW pracy przedstawiono analizę geometrycznych warunków wejścia i wyjścia ostrza piły z materiału obrabianego przy przecinaniu drewna. Przedstawiono czasowy i przestrzenny rozkład geometrycznych parametrów wejścia i wyjścia ostrza i ich wpływ na trwałość ostrzy i dokładność przecinania.
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Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublicationThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
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Fracture mechanics model of cutting power versus widespread regression equations while wood sawing with circular saw blades
PublicationA comparison of the theoretical cutting power consumption results forecasted with the model (FM_CM model) which include work of separation (fracture toughness) in addition to plasticity and friction, and two widespread regression equations while wood sawing with circular saw blades has been described. in and cutting power consumption forecasted. In computations of the cutting power consumption during rip sawing of Scots pine wood...
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Economical wood sawing with circular saw blades of a new design (Ekonomicno piljenje drva kruznom pilom novog dezajna)
PublicationMaterial-saving and energy-saving belong to the basic requirements imposed on contemporary manufacturing processes. The realization of these processes gives measurable profi ts, not only economical butalso ecological. In the case of wood sawing with circular saw blades, material- and energy-savings are dependent on total overall set of teeth (theoretical kerf) and teeth position accuracy in relation to the workpiece. Hence, it...
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Opracowanie ekspertyzy dotyczącej przyczyn pękania łopatek wirnika SP turbiny PG1 typu 13UP55
PublicationZakres badań i analiz dotyczył ustalenia przyczyn pękania elementów łopatek wirnika SPA5 turbiny TG1 typu 13UP55 obejmował: 1. wykonanie badań składu chemicznego stali, z której wykonano łopatki dostarczone przez Zleceniodawcę dwoma metodami, 2. badania mikroobszarów zniszczenia łopatek na mikroskopie elektronowym skaningowym z mikroanalizatorem EDS, 3. badania metalograficzne makroskopowe i mikroskopowe fragmentów...
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Methodology of the Morphometry Study on Baltic Herring
PublicationAcoustic techniques are used in the estimation of the abundance of Baltic herring. Investigations of the relationship between the Baltic herring individual target strength TS and the total fish length L, significant in the acoustic assessment, demonstrated its de-pendence on the study area location. It motivated the detailed analysis of the relationship between herring from the southern Baltic ICES Subdivisions 24, 25, and 26,...
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Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine
PublicationResearch regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency...
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Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results
PublicationThis paper presents selected results and aspects of themultidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of awind turbine blade structure.Themain goal of the conducted research is to validate finite elementmodel of themodified wind turbine blade section mounted in the flexible support structure accordingly to the...
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Report on investigation of turbine blade from main engine turbocharger 420.34 from M/V "Nordstraum"
PublicationWykonano badania pęknięcia na łopatce turbiny turbodoładowania silnika głównego. Ustalono, ze przyczyną pęknięcia była korozja międzykrystaliczna.
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Mode vibrations of plates – experimental analysis
PublicationIn this paper results of the square MDF plate and circular saw blades examination with the use of the harmonic method to static identification of resonant frequencies and shapes of mode vibrations are presented. Obtained results reveled that for circular saws with large holes in a saw blade appeared two resonant frequencies for the same nodal number.
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The Unsteady Low-Frequency Forces Acting on the Rotor Blade in the First Stage on an Axial Compressor of SO-3 Jet Engine
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On a Method of Efficiency Increasing in Kaplan Turbine
PublicationThis paper presents a method of increasing efficiency in Kaplan-type turbine. The method is based on blade profile optimisation together with modelling the interaction between rotor and stator blades. Loss coefficient was chosen as the optimisation criterion, which is related directly to efficiency. Global optimum was found by means of Genetic Algorithms, and Artificial Neural Networks were utilised for approximations to reduce...
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Application of neural networks for identification of forcedness having effect on magnitude of turbine rotor vibration using pressure distribution in blade tip clearance.
PublicationW pracy sprawdzono, czy zastosowanie sieci neuronowych umożliwia identyfikację wymuszeń powstających w wyniku funkcjonowania maszyny jak i zależnych od jej stanu mechanicznego przy zastosowaniu rozkładu ciśnienia w uszczelnieniu nadbandażowym. Przeprowadzono pomiary rozkładu ciśnienia dla różnych warunków pracy, uwzględniając zmianę mimośrodu oraz zmianę skośnego ustawienia osi wirnika względem osi korpusu. Dokonano analiz przy...
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Unusual odd-chain and trans-octadecenoic fatty acids in tissues of feral European beaver (Castor fiber), Eurasian badger (Meles meles) and raccoon dog (Nyctereutes procyonoides).
PublicationW lipidach wyizolowanych z różnych partii ciała bobrów, borsuków i jenotów stwierdzono obecność znaczących ilości niezwykłych jak na zwierzęta jednożołądkowe kwasów tłuszczowych - nieparzystowęglowych nasyconych i jednonienasyconych KT (15:0, 17:0, 15:1 i 17:1) oraz (w lipidach tkanek bobra i jenota) oktadecenowych KT konfiguracji trans, w tym kwasu wakcenowego - KT charakterystycznych dla tkanek i mleka przeżuwaczy. Obecność tych...
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MACHINE VISION DETECTION OF THE CIRCULAR SAW VIBRATIONS
PublicationDynamical properties of rotating circular saw blades are crucial for both production quality and personnel safety. This paper presents a novel method for monitoring circular saw vibrations and deviations. A machine vision system uses a camera and a laser line projected on the saw’s surface to estimate vibration range. Changes of the dynamic behaviour of the saw were measured as a function of the rotational speed. The critical rotational...
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Uncertainty quantification of modal parameter estimates obtained from subspace identification: An experimental validation on a laboratory test of a large-scale wind turbine blade
PublicationThe uncertainty afflicting modal parameter estimates stems from e.g., the finite data length, unknown, or partly measured inputs and the choice of the identification algorithm. Quantification of the related errors with the statistical Delta method is a recent tool, useful in many modern modal analysis applications e.g., damage diagnosis, reliability analysis, model calibration. In this paper, the Delta method-based uncertainty...
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Circular saw vibrations or dynamics of the spindle
PublicationSawing of wood with circular saws is a typical example of cutting with multi-blade tools. In that kind of cutting, theposition accuracy of following tool blades is a crucial factor which affects the cutting process and machining final effects.Position tooth errors may cause deterioration in cutting conditions, changes in loads of individual teeth and the tool as a whole,and also a decrease in accuracy and surface quality after...
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Price convergence in the European Union and in the new member states
PublicationThis paper examines price dispersion in the European Union (EU15) and in three New Member States (Poland, Hungary and the Czech Republic) between 1995 and 2006. The analysis utilizes both disaggregate and aggregate price data, including the prices of 157 products and two indices constructed using two different weighting procedures. For each category of goods the price dispersion is lower in EU15 than EU15 plus 3 NMS. Sigma convergence...
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On design and analysis of flow characteristics of the last stage of gas-steam turbine
PublicationResearch regarding blade design and analysis of flow have been conducted for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics (CFD) and computational flow mechanics (CFM). Currently a combination of mentioned methods is used for design of turbine blades. These methods enabled us to improve flow efficiency...
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Polymer biodegradable coatings as active substance release systems for urological applications
PublicationCatheter-associated urinary tract infections are the result of catheterization of the bladder. The risk of infection is directly proportional to the length of the bladder catheterization. Bacteria cells have the ability to adhere and create the biofilm on the surface of catheter materials. Bacteria’s biofilm is an extremely beneficial environment of existence for microorganisms. Microorganisms that are an integral part of the biofilm...
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TERMODYNAMIC CALCULATIONS OF TURBINE STEAM PARAMETERS
PublicationIn this work a heat balance was made for the nominal conditions of a block working with 18K370 turbine. For the parameters obtained, the thermal-flow calculations of the steam turbine were performed, maintaining the actual geometry of its flow system. Based on the nominal values obtained, iterative thermal and flow calculations were made for both the heat cycle of the power plant block and the steam turbine itself, seeking to obtain...
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Stock Exchanges Indices and Abnormal Returns in the Crisis Condition
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Corporate Reputation and Economic Performance: the Evidence from Poland
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The Ownership Structure and the Performance of the Polish Stock Listed Companies
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Measurement of corporate reputation as perceived by investors
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Design and investigations of a micro-turbine flow part
Publication-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The heat output of the plant was assumed equal to 20 kW, while the electric output amounted to about 3kW.In the paper a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of the particular experimental investigations and numerical calculations are shown,...
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3,3'-Dibenzoyl-1,1'-dibenzyl-1,1'-(ethane-1,2-diyl)dithiourea
PublicationIn the title compound, C32H30N4O2S2, the carbonyl and thiocarbonyl groups are found in a rare synclinal conformation, with an S-C···C-O pseudo-torsion angle of 62.6(2)°. The molecule has Ci = S2 point-group symmetry with a crystallographic center of inversion located in the middle of the ethylene bridge. One of the symmetry-independent phenyl...
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Linux scheduler improvement for time demanding network applications, running on Communication Platform Systems
PublicationCommunication Platform Systems as ex. ATCA standard blades located in standardized chassis provides high level communication services between system peripherals. Each ATCA blade brings dedicated functionality to the system but can as well exist as separated host responsible for servicing set of task. According to platform philosophy these parts of system can be quite independent against another solutions provided by competitors....
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Bader Ginsburg, Ruth, oraz Hartnett, Mary i Williams, Wendy W. Moimi słowami. Przeł. Anna Halbersztat i Anna Klingofer-Szostakowska. Lublin: Fame Art, 2021 (ss. 400, ISBN 9788395409660)
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Fracture Toughness and Shear Yield Strength Determination for Two Selected Species of Central European Provenance
PublicationWhen offcut of wood is formed by shearing, Atkins’s analyses of sawing processes can be applied. Using this modern approach, it is possible to determine the fracture toughness and shear yield strength of wood. This model is only applicable for the axial-perpendicular cutting direction because both of these parameters are suitable for the given direction of cutting edge movement and cannot be considered material constants. Alternatively,...
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Investors are more Sensitive to Information about Financial Rather than Ethical Reputation of a Company: Evidence from an Experimental Study
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Financial determinants of corporate reputation: A short-term approach
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Corporate governance and propensity to share information: The long-run effect
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Comparison of Surface Quality and Tool-Life of Glulam Window Elements after Planing
PublicationThe quality of the surface of wooden elements, that have been planed, has a crucial importance in the whole production process, since the obtained effects affect the quality of wooden surface after fi nishing (painting). The occurrence of defects is usually the reason for qualifying a workpiece as scrap or for requiring additional work. This paper presents the selected results of research of the effect of the cutting tool wear...
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ANALIZA AERODYNAMICZNA ŁOPAT NA PRZYKŁADZIE PROJEKTU DWUWIRNIKOWEJ TURBINY WIATROWEJ MAŁEJ MOCY
PublicationW artykule przedstawiono proces projektowania oraz analizy aerodynamicznej łopat turbiny wiatrowej z wykorzystaniem metody BEMT (ang. Blade Element Momentum Theory). Dokonano doboru profili aerodynamicznych oraz opisano procedurę wyznaczania optymalnego rozkładu kątów zwichrowania i długości cięciw profili w funkcji długości łopaty dla założonych parametrów wejściowych. Dokonano obliczenia działających sił oraz generowanej mocy...
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Ring thruster - a preliminary optimisation study
PublicationThe ring thruster is a new type of propeller, for which there is no experimental data to verify analytical design calculations. A significant feature of the ring thruster is the absence of a shaft. Propeller blades are mounted to the ring rotating inside the housing, which has the shape of a nozzle. For this reason the ring thruster is closest, with respect to both the construction and principle of operation, to the Kort nozzle...
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Complex multidisciplinary optimization of turbine blading systems
PublicationThe paper describes the methods and results of direct optimization of turbine blading systems using a software package Opti_turb. The final shape of the blading is obtained from minimizing the objective function, which is the total energy loss of the stage, including the leaving energy. The current values of the objective function are found from 3D RANS computations (from a code FlowER) of geometries changed during the process...
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Modeling of Common Mode Currents Induced by Motor Cable in Converter Fed AC Motor Drives
PublicationInvestigation of conducted EMI generation in AC motor fed by pulse width modulated frequency converters requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. Motor voltage transients and related common mode currents are significantly correlated with resonance effects occurring in load circuits. An analysis of frequency converter load impedance-frequency characteristics...
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Recovering Evaluation of Narrow-Kerf Teeth of Mini Sash Gang Saws
PublicationSash gang saws with narrow-kerf saw blades are used in the production of glued laminate flooring elements in plants where dry technology is applied. This means that boards or friezes are sawn into top layer lamellae in dry conditions (moisture content of about 10–12%) from expensive wood species, often exotic. The object of this research was stellite-tipped teeth of narrow kerf saw blades sharpened under industrial conditions....
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Eulerian motion magnification applied to structural health monitoring of wind turbines
PublicationSeveral types of defects may occur in wind turbines, as physical damage of blades or gearbox malfunction. A wind farm monitoring and damage prediction system is built to observe abnormal vibrations of elements of wind turbine: blades, nacelle, and tower. Contactless methods are developed which do not require turbine stopping. In this work, structural health monitoring of a wind turbine is evaluated using a conversion from the captured...
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Financial risk information avoidance
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Leading Behavioral Characteristics and Investors’ Decisions: An Experimental Approach
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Broadband Modeling of Motor Cable Impact on Common Mode Currents in VFD
PublicationExamination of conducted EMI generation and propagation in AC motor drives fed by frequency converter requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. AC motor winding voltage transients and related common mode currents are significantly correlated with resonance effects occurring in converter's load circuits. Intensity levels of these phenomena depend...