Search results for: BLADE VIBRATIONS
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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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Earthquake-induced pounding between asymmetric steel buildings
PublicationEarthquake-induced pounding between buildings has been the subject of numerous numerical and experimental studies in the resent years. The phe-nomenon may cause severe damage to structural elements as well as may also lead to the total collapse of colliding structures. A major reason leading to pounding between adjacent, insufficiently separated buildings results from the differences in their dynamic properties. The aim of this...
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Molecular hydrogen solvated in water – A computational study
PublicationThe aqueous hydrogen molecule is studied with molecular dynamics simulations at ambient temperature and pressure conditions, using a newly developed flexible and polarizable H2 molecule model. The design and implementation of this model, compatible with an existing flexible and polarizable force field for water, is presented in detail. The structure of the hydration layer suggests that first-shell water molecules accommodate the...
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Numerical investigation on dynamic performance of a multi-storey steel structure model and comparison with experimental results
PublicationShaking table testing is the most commonly adopted method to simulate earthquake forces. This approach allows us to analyze the dynamic performance and provides a valuable insight into the dynamics of building structures, which helps to improve their future safety and reliability. The present study aims to conduct a numerical evaluation of dynamic response of a multi-storey steel structure model, which was previously examined during...
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Excited states of isoxazole molecules studied by electron energy-loss spectroscopy
PublicationElectron energy-loss spectra were measured in isoxazole in the excitation energy range 3.5−10 eV to investigate the valence excited states. Spectra recorded at different scattering conditions enabled the identification of the singlet and triplet states and the determination of their vertical excitation energies. The two lowest energy triplet bands, ππ* 13A' and ππ* 23A' at 4.20 and 5.30 eV, respectively show vibrational progressions....
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Visual Detection of People Movement Rules Violation in Crowded Indoor Scenes
PublicationThe paper presents a camera-independent framework for detecting violations of two typical people movement rules that are in force in many public transit terminals: moving in the wrong direction or across designated lanes. Low-level image processing is based on object detection with Gaussian Mixture Models and employs Kalman filters with conflict resolving extensions for the object tracking. In order to allow an effective event...
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High-quality Experiment Dedicated to microGravity Exploration, Heat Flow and Oscillation Measurement from Gdańsk
PublicationIn this paper we propose HEDGEHOG (High-quality Experiment Dedicated to microGravity Exploration, Heat flow and Oscillation measurement from Gdańsk) REXUS experiment to investigate vibrational and heat flow phenomena during the whole (ascent, microgravity phase, descent and recovery) flight of a sounding rocket. First, a proposed system of cantilever beams is discussed to study dynamic behaviour of dummy payload. Dimensioning has...
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Ecological bearing systems for water turbines – research and development at Gdansk University of Technology
PublicationIncreasing requirements for environmental protection make it necessary to introduce new materials and designs. Hydroelectric power plants operating in direct contact with water reservoirs and rivers are potentially endangering water cleanliness, hence they should also be modernized in the way minimizing the environmental hazards. A lot of progress in this field has been achieved in last decades, but still there is much work to...
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STRENGTH of MATERIALS TOWARDS APPLICATIONS (2024)
e-Learning CoursesThe SMTA DATE Course consists of the following problems to be discussed during the lectures: - Introduction to strength of materials towards applications - Fundamentals of modelling in strength of materials towards applications - Materials and basic structures - Fundamentals of modelling in strength of materials towards applications - Definition of environment and loads - General, energy-based and advanced methods for analysis...
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Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations
PublicationThe high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3–10.8 eV (290–115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured...
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Electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations of ethyl acetate
PublicationThe high-resolution vacuum ultraviolet photoabsorption spectrum of ethyl acetate, C4H8O2, is presented over the energy range 4.5−10.7 eV (275.5−116.0 nm). Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Also, the photoabsorption cross sections...
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The conception of energetic investigations of the multisymptom fatigue of the simple mechanical systems' constructional materials
PublicationThe article presents the basic assumptions of the research project aimed, as the main scientific purpose, an identification of the slow-changeable energy processes surrounding the high-cycle fatigue of constructional materials within the plain mechanical system, especially the marine one, for diagnostic purposes. There is foreseen an application of alternative diagnostic methods based on energetic observations of the multi-symptom,...
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Induction motor bearings diagnostic indicators based on MCSA and normalized triple covariance
PublicationInduction motors are one of the most widely used electrical machines. Statistics of bearing failures of induction motors indicate, that they constitute more than 40% of induction motor damage. Therefore, bearing diagnosis is so important for trouble-free work of induction motors. The most common methods of bearing diagnosis are based on vibration signal analysis. The main disadvantage of those methods is the need for physical access...
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MCSA with Normalized Triple Covariance as a bearings diagnostic indicator in an induction motor
PublicationStatistics of bearing failures in induction motors indicate, that they constitute more than 40% of IM damage, therefore bearing diagnosis is very important. Vibration methods for bearing diagnostics have one major disadvantage - they require the availability of the machine for sensors installation. This is the reason for seeking new methods based on motor supply current analysis. Diagnosis of induction motors, conducted remotely...
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2022-2023 - Strenght of materials towards applications, PG_00053661
e-Learning CoursesThe course is mainly dedicated to the DAPE Students. From the theoretical point of view the course consists of the following problems to be discussed during the lectures and exercises: -fundamentals of strength of materials -basic structures and environment -loads on structures -strength of materials: tension, stress, analysis of stress and strain, bending moments and shearing forces, longitudinal and shearing stress in beams,...
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Strenght of materials towards applications , PG_00053661
e-Learning CoursesThe course is dedicated to the DAPE WIMiO Students. From the theoretical point of view the course consists of the following problems to be discussed during the lectures: -fundamentals of strength of materials -basic structures and environment -loads on structures -strength of materials: tension, stress, analysis of stress and strain, bending moments and shearing forces, longitudinal and shearing stress in beams, bending stress...
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Modelling of Thyroid Peroxidase Reveals Insights into Its Enzyme Function and Autoantigenicity
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An innovative approach to the forecasting of energetic effects while wood sawing
PublicationIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture...
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An Innovative Approach to the Forecasting of Energetic Effects While Wood Sawing
PublicationIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specifi c cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture mechanics....
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Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine
PublicationA small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performancehas been investigated numerically. Results of a parametric study have been presented in this paper.As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected.Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT).Simulations were carried out with Computational Fluids...
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Modeling of wood frame structures with different insulation materials under damaging dynamic loading
PublicationWood frame buildings are very popular in regions that are exposed to different dynamic excitations, such as damaging earthquakes. Their seismic resistance is really important in order to prevent structural damages and human losses. This paper presents the results of advanced numerical investigation carried out using the FEM. Based on the models of wall panels, the numerical model of real structure of the wood frame building has...
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Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface
PublicationCore-interlayer-shell Fe3O4/SiO2/TiO2, CoFe2O4/SiO2/TiO2 and BaFe12O19/SiO2/TiO2 magnetic photocatalysts were obtained. A water-in-oil microemulsion system with suitable surfactants was used for functionalization of the magnetic core with silica interlayer and TiO2-based photocatalyst. Uncoated and coated particles were characterized by electrophoretic meaurements, X-ray diffractometry (XRD), scanning electron microscopy (SEM),...
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An adaptive-noise Augmented Kalman Filter approach for input-state estimation in structural dynamics
PublicationThe establishment of a Digital Twin of an operating engineered system can increase the potency of Structural Health Monitoring (SHM) tools, which are then bestowed with enhanced predictive capabilities. This is particularly relevant for wind energy infrastructures, where the definition of remaining useful life is a main driver for assessing the efficacy of these systems. In order to ensure a proper representation of the physical...
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Cancer-selective, single agent chemoradiosensitising gold nanoparticles
PublicationTwo nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and...
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Failure analysis of a high-speed induction machine driven by a SiC-inverter and operating on a common shaft with a high-speed generator
PublicationDue to ongoing research work, a prototype test rig for testing high-speed motors/generators has been developed. Its design is quite unique as the two high- speed machines share a single shaft with no support bearings between them. A very high maximum operating speed, up to 80,000 rpm, was required. Because of the need to minimise vibration during operation at very high rotational speeds, rolling bearings were used. To eliminate...
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Areas of Fan Research—A Review of the Literature in Terms of Improving Operating Efficiency and Reducing Noise Emissions
PublicationFans as industrial devices are among the most significant single recipients of driving energy. Therefore, they represent an important area of energy savings to reduce CO2 emissions. The ubiquity of fans and their operation under conditions different from the optimum provides an opportunity for more significant global reductions in the energy used to drive them. The second important aspect, besides energy efficiency, related to...
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Dynamic analysis of the railway bridge span under moving loads
PublicationThe first part of this paper provides a review of the state of knowledge of the dynamic behaviour of railway bridges under moving loads. Particular attention is paid to developments in modelling railway bridge loading and dynamic vehicle-span (structure) interaction. The most important aspects determining the advancements in this area of knowledge are identified. The contemporary techniques for defining bridge span finite element...
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Configurations of H 3 + (H2)n clusters and their energies
PublicationThe H-3(+) ion plays an important role in low temperature astrophysical and laboratory plasmas. It is considered as the initiator of many ion-molecule chemistries. Also its clusters with H-2 are quite interesting. We study configurations of the H-3(+)(H-2)(n) clusters for n = 1 up to n = 12 as a simple test system. Total energies for these structures, with zero point vibration corrections have been calculated. Stabilization energies...
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Propensity of salicylamide and ethenzamide cocrystallization with aromatic carboxylic acids
PublicationThe cocrystallization of salicylamide (2-hydroxybenzamide, SMD) and ethenzamide (2-ethoxybenzamide, EMD) with aromatic carboxylic acids was examined both experimentally and theoretically. The supramolecular synthesis taking advantage of the droplet evaporative crystallization (DEC) technique was combined with powder diffraction and vibrational spectroscopy as the analytical tools. This led to identification of eleven new cocrystals...
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Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 2014
PublicationSince offshore wind turbine supporting structures are subjected to dynamic environments with time-varying loading conditions, it is important to model their dynamic behavior and validate these models by means of vibrational experiments. In this paper assessment of dynamical state of the structure is investigated by means of both: numerical modeling, and experimental modal analysis. In experimental modal analysis, capturing the...
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Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations
PublicationThe highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies...
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Convenient and efficient N-methylation of secondary amines under solvent-free ball milling conditions
PublicationIn the present work, we report the development of a rapid, efcient, and solvent-free procedure for the N-methylation of secondary amines under mechanochemical conditions. After optimization of the milling parameters, a vibrational ball mill was used to synthesize 26 tertiary N-methylated amine derivatives in a short time of 20 min (30 Hz frequency) and high yields ranging from 78 to 95%. An exception was compounds having a hydroxyl...
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Design Analysis of Micro Gas Turbines in Closed Cycles
PublicationThe problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work...
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Pre-swirl energy saving device in marine application
PublicationThis paper covers topics of energy saving device (ESD) with application to marine propulsors. The form of ESD, considered in this paper, consists of fixed lifting foils mounted in front of the screw propeller (the pre-swirl stator/guide vanes). An algorithm for designing propulsion systems, consisting of guide vanes and screw propeller, is presented. The proposed method relies on hybrid lifting line (guide vanes)-lifting surface...
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Behaviour of asymmetric structures with base isolation made of Polymeric Bearings
PublicationEarthquake-induced ground motions are the most severe and unpredictable threats to the structures all around the world. Seismic excitations cause a lot of damage in a wide variety of ways, leaving thousands of casualties in their wake. During the last few years alone, the world has witnessed many major earthquakes, five of which have caused far-reaching consequences of a national scale for Haiti (January 2010), Chile (February...
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Multi Parameter Sliding Test Result Evaluation for The Selection of Material Pair for Wear Resistant Components of a Hydraulic motor Dedicated for Use With Environmentally Friendly Working Fluids
PublicationIn the paper the method and results are presented of the testing of tribological performance of a number of hard materials available commercially. The tests consisted in unidirectional sliding with liquid lubrication. The load and velocity regime chosen were similar to a standard four-ball lubricity test with constant velocity and load increasing over time. The regime was modified in such a way that over the initial part of the...
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SPECTRAL RESPONSE OF STATIONARY JACK-UP PLATFORMS LOADED BY SEA WAVES AND WIND USING PERTURBATION METHOD
PublicationThe paper addresses non-linear vibrations of offshore jack-up drilling platforms loaded by sea waves and wind in their stationary condition using the perturbation method. Non-linearity of dynamic equations of motion for fixed offshore platforms yields from two factors. The first is load excitation generating non-linear velocity coupling in a dynamic system. This coupling is inherent in the modified Morison equation, involving the...
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ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART II IDENTIFICATION STUDIES – DEVELOPING THE FATIGUE DURABILITY MODEL OF A DRIVE SHAFT
PublicationThe article presents a continuation of research carried out concerning identification of energy consequences of mechanical fatigue within a propeller shaft in a rotating mechanical system, while working under conditions of the loss of the required alignment of shaft lines. Experimental research was carried out on a physical model reflecting a full-sized real object: i.e., the propulsion system of the ship. It is proven, by means...
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Analysis of start energy of Stirling engine type alpha
PublicationThe Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the...
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Analysis of temporary steel grandstand with different bracing systems exposed to crowd load
PublicationGrandstands are structures which are regularly subjected to dynamic loads generated by crowd motions. It is a dangerous situation when spectators induce rhythmic jumping, dancing, stamping, etc. If the synchronized movement of spectators excites a natural frequency of the structure, resonant response might occur. To avoid such situations, temporary steel grandstands are commonly strengthened using additional elements that create...
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Advanced Hysteretic Model of a Prototype Seismic Isolation System Made of Polymeric Bearings
PublicationThe present paper reports the results of acomprehensive study designed to verify the effectiveness of an advanced mathematical model in simulating the complex mechanical behaviour of a prototype seismic isolation system made of polymeric bearings (PBs). Firstly, in order to construct the seismic bearings considered in this research, a specially prepared flexible polymeric material with increased damping properties was employed....
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The influence of polarization of titania nanotubes modified by a hybrid system made of a conducting polymer PEDOT and Prussian Blue redox network on the Raman spectroscopy response and photoelectrochemical properties
PublicationIn this work we show the impact of applied potential on network vibrations and photoelectrochemical properties of a composite material containing hydrogenated titania nanotubes and poly (3,4-ethylenedioxythiophene) with iron hexacyanoferrate (H-TiO2/pEDOT:Fehcf) acting as a redox centre. For this purpose, Raman spectroscopy measurements under the working electrode (WE) polarization were carried out, allowing investigation of changes...
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Solar light driven degradation of textile dye contaminants for wastewater treatment – studies of novel polycationic selenide photocatalyst and process optimization by response surface methodology desirability factor
PublicationThe unplanned anthropogenic activities and raced industrial revolution detrimentally causes serious threat to terrestrial and aquatic life. A high discharge of wastewater from industries using dyes affects living organisms and the environment. This paper presents studies on polycationic selenides (PCS) synthesized by hydrothermal methods for photocatalytic degradation of dyes. The synthesized PCS were confirmed by various characterization...
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Wpływ sposobu odwzorowania pojazdu szynowego na odpowiedź dynamiczną przęsła mostowego
PublicationW pracy przedstawiono rezultaty analiz numerycznych oraz badań eksploatacyjnych dwóch przęseł mostowych wymuszonych ruchomym pojazdem szynowym. Pojazd odwzorowano za pomocą czterech modeli uproszczonych: strumienia sił skupionych, strumienia mas skupionych oraz strumieni oscylatorów jedno- i dwumasowych. Analizy numeryczne wykonano przy wykorzystaniu MES. Potrzebne parametry dynamiczne wyznaczono na podstawie wyników identyfikacji...
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New ceramic materials derived from pyrolyzed poly(1,2-dimethylsilazane) and starch as a potential anode for Li-ion batteries
PublicationNewmaterialswere obtained by pyrolysis of starch (S) and poly(1,2-dimethylsilazane) (PSN) (weight ratio: PSN/S 30/70) at temperature a) 500 °C, b) 700 °C and c) 900 °C. Ceramic materials were characterized by infrared spectroscopy, TGA, Raman spectroscopy and SEM. New Si\O and shifted Si\C stretching vibration modes emerged confirming direct interaction between silicon originating fromsilazane and oxygen coming fromstarch. The...
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Estimation of nonstructural stiffness in instrumented steel frames
PublicationLateral stiffness of nonstructural components may significantly influence the initial stiffness of the entire structure and consequently alter its dynamic characteristics. While methods for simulating structural members are well-established, approaches for modeling nonstructural components that also participate in seismic response are notably less developed. In this paper a simplified, physically-intuitive approach for estimating...
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Anatomy of noise in quantitative biological Raman spectroscopy
PublicationRaman spectroscopy is a fundamental form of molecular spectroscopy that is widely used to investigate structures and properties of molecules using their vibrational transitions. It relies on inelastic scattering of monochromatic laser light irradiating the specimen. After appropriate filtering the scattered light is dispersed onto a detector to determine the shift from the excitation wavelength, which appears in the form of...
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Evolutionary Planning of Safe Ship Tracks in Restricted Visibility
PublicationThe paper presents the continuation of the author's research on ship track planning by means of Evolutionary Algorithms (EA). The presented method uses EA to search for an optimal set of safe tracks for all ships involved in an encounter. Until now the method assumed good visibility – compliance with standard rules of the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS, 1972). However, in restricted...
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Ultrafast Intramolecular Relaxation and Wave-Packet Motion in a Ruthenium-Based Supramolecular Photocatalyst
PublicationThe hydrogen-evolving photocatalyst [(tbbpy)2 Ru(tpphz)Pd(Cl)2 ](2+) (tbbpy=4,4'-di-tert-butyl-2,2'-bipyridine, tpphz=tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) shows excitation-wavelength-dependent catalytic activity, which has been correlated to the localization of the initial excitation within the coordination sphere. In this contribution the excitation-wavelength dependence of the early excited-state relaxation...
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Optical emission spectroscopy of plasma generated by a waveguide-supplied microwave plasma source operated at 915MHz
PublicationIn this paper we present the results of an optical emission spectroscopic study of an atmospheric pressure microwave (915 MHz) nitrogen and nitrogen with carbon dioxide (1%) plasma at high working gas flow rate. This study was aimed at determining rotational Trot and vibrational Tvib temperatures of N+2 ions and N2, CN molecules. The plasma was generated in a waveguide-supplied cavity-resonant type microwave plasma source. All...