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Search results for: PROPAGATION OF ACOUSTIC WAVES IN WATER LAYER
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Experimental Investigation of Elastic Waves Propagation in 1D and 2D Structures with Faults.
PublicationW pracy omówiono wyniki pomiarów fal sprężystych w prętach, belkach i płytach z uszkodzeniami.
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Structural and dynamic properties of water within the solvation layer around various conformations of the glycine-based polypeptide
PublicationSeveral conformations of the solvated glycine-based polypeptides were investigated using molecular dynamics simulations. Some properties of water in the neighbouring space around these molecules were investigated. It was found, that water forms a well-defined layer - the first solvation shell - around the peptide molecule, and thickness of this layer is independent of the peptide structure, and it equals to approximately 0.28 nm....
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Structural and Dynamic Properties of Water within the Solvation Layer around Various Conformations of the Glycine-based Polypeptide
PublicationSeveral conformations of the solvated glycine-based polypeptides were investigated using molecular dynamics simulations. Some properties of water in the neighboring space around these molecules were investigated. It was found that water forms a well-defined layer—the first solvation shell—around the peptide molecule, and thickness of this layer is independent of the peptide structure and is equal to approximately 0.28 nm. Within...
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Weakly nonlinear dynamics of short acoustic waves in exponentially stratified gas
PublicationRozpatruje się dynamika krótkich (w porównywaniu z charakterystyczną skalą zmiany gęstości gazu atmosferycznego) fal akustycznych. Wyprowadzone nowe równanie ewolucyjne, które uwzględnia dyspersję i nieliniowy charakter propagacji tych fal. Porównuje sie liniowa i nieliniowa dynamika. Ilustracje propagacji, numeryczne wyliczione na podstawie nowych wzorów, są przedstawione. Indexed and abstracted (from vol. 32(1) 2007) in Science...
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Interaction of vortical and acoustic waves: from general equations to integrable cases
PublicationWyprowadzono operatory rzutu przepływu w warstwie lepkiej przyściennej na podstawowe typy ruchów. Wyprowadzono również układy równań dynamicznych sterujących przepływem. Zaproponowano metody analityczne dalszego rozwiązywania tych równań.
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Nondestructive global corrosion measurement using guided wavefield data
PublicationMetallic structures often face degradation, and corrosion ranks among the most prevalent forms of deterioration. Accurate quantification of corrosion is crucial, especially for structures exposed to harsh environmental conditions, such as marine vessels and offshore installations. Because the traditional measurement methods based on scanning by ultrasonic gauge are time-consuming and provide only rough information on the thickness...
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A note on the vertical distribution of momentum transport in water waves
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Spectral Finite Element Method for Propagation of Elastic Waves in Wind Turbine Blades for SHM
PublicationW pracy przedstawiono model łopaty turbiny wiatrowej zbudowany z wykorzystaniem spektralnych elementów skończonych. Omówiono wyniki symulacji propagacji fal sprężystych i ich interakcji z uszkodzeniami w formie pęknięcia i delaminacji.
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Damage detection strategies for aircraft shell-like structures based on propagation guided elastic waves
PublicationW pracy przedstawiono mozliwości detekcji uszkodzeń w lotniczych konstrukcjach powłokowych z wykorzystaniem fal sprężystych. Omówiono kilka strategii detekcji uszkodzeń. Przedstawiono wyniki symulacji numerycznych z wykorzystaniem metody spektralnych elementów skończonych, jak również wynik badań eksperymentalnych z zastosowaniem wibrometrii laserowej.
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REVERSE MODELLING OF MICROSEISMIC WAVES PROPAGATION FOR THE INTERPRETATION OF THE DATA FROM HYDRAULIC FRACTURING MONITORING IN POLAND
PublicationA hydraulic fracturing job was performed to stimulate gas flow from a horizontal wellbore located in Poland. The whole operation was overseen by means of microseismic monitoring. For this purpose, an array of 12000 geophones was deployed on ground in form of patches distributed unevenly in a region of 4km from the wellbore. The array was constantly recording seismic signals during whole fracturing processed. Such recorded signals...
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WATER LUBRICATED MAIN SHAFT BEAR INGS WITH THREE LAYER BUSH – MODERN SOLUTION FOR MARINE INDUSTRY
PublicationWater lubricated sliding bearings are increasingly popular in marine and hydro power industry. Such popularity is partly due to their simple construction which also means a relatively affordable price. Properly designed and installed water lubricated bearings may well last for over a decade. During the last decade their traditional range has been expanded with new, modern products like three layer bearing bush. The work presents...
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Acoustic lifecycle study of the double-layer porous asphalt on E4 in Huskvarna, Sweden
PublicationIn 2010 a double-layer porous asphalt concrete (DPAC) pavement was constructed on the E4 motorway through the Swedish city Huskvarna. Earlier experience in Sweden indicated that it was feasible to obtain a high initial noise reduction but due to the widespread use of studded tires in winter, clogging and ravelling created losses of around 2 dB per year, with an expected acoustical lifetime of only 3 years. However, the improved...
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Shipping Low Frequency Noise and Its Propagation in Shallow Water
PublicationOne of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c/h, where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears....
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On the usefulness of selected radio waves propagation models for designing mobile wireless systems in container terminal environment
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Testing OFDM Transmission Schemes for Shallow Water Acoustic Communications
PublicationLarge variability of communication properties of underwater acoustic channels, and especially strongly varying instantaneous conditions in shallow waters, is a tough challenge for the designers of underwater acoustics communication (UAC system. There is a need for developing adaptive signaling schemes that would dynamically optimize signal parameters in both physical and link layers of communication protocols. The orthogonal frequency...
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Liquid water. Analytical equation of state and acoustic parameters evaluation.
PublicationRównanie stanu dla ciekłej wody zaproponowane przez Jefferya - Austina zastosowano do obliczeń prędkości dźwięku oraz parametru nieliniowości B/A. Parametry akustyczne są porównywane z danymi doświadczalnymi.
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Passive layer cracking studies performed on A95056 Aluminum Alloy by DEIS and acoustic emission
PublicationZbadano proces pękania warstwy pasywnej na stopie aluminium A95056 w warunkach zmiennych naprężeń rozciągających i polaryzacji anodowej z wykorzystaniem techniki DEIS oraz emisji akustycznej (AE), jako metody porównawczej. Określono elektrochemiczne i mechaniczne przyczyny badanego procesu. Wyznaczono progową (krytyczną) wartość naprężeń, przy których zarejestrowano proces pękania warstwy pasywnej na badanym stopie aluminium. Badanemu...
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Water desalination using membrane distillation with acidic stabilization of scaling layer thickness
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Investigations on the influence CuO doping on elastic properties of Li2SO4–MgO–P2O5 glass system by means of acoustic wave propagation
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Influence of NiO doping on elastic properties of Li2SO4-MgO-P2O5 glass system-Investigation by means of acoustic wave propagation
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Geographic information system for remote integration of diverse under-water acoustic sensor data
PublicationMaritime and port areas throughout the world are exposed to many different hazards, like pollution, terrorism and natural disasters. Early detection, identification and preparation of appropriateesponse strategies is especially important in the case of semi-enclosed basins like the Baltic Sea, mainly due to the marine ecosystems' continuous absorption of pollutants including oil, heavy metals and chemicals. Many of those agents...
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Experimental studies on the impact of changing the pipe material on the propagation of the pressure wave during water hammer
PublicationAim of the paper is to present the results studying the water hammer phenomenon in pipes made of different materials, and to show the impact of changing the type of material of the pipe on the velocity of the pressure wave during the transient flow in the pipes. In terms of research material and methods, pipes made of galvanized steel and high-density polyethylene were tested. Measurements were made using strain gauges with a high...
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Evaluation, Pitfalls and Recommendations for the “Water Layer Test” for Solid Contact Ion‐selective Electrodes
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Some new soliton solutions to the higher dimensional Burger–Huxley and Shallow water waves equation with couple of integration architectonic
PublicationIn this paper, we retrieve some traveling wave, periodic solutions, bell shaped, rational, kink and anti-kink type and Jacobi elliptic functions of Burger’s equation and Shallow water wave equation with the aid of various integration schemes like improved -expansion scheme and Jacobi elliptic function method respectively. We also present our solutions graphically in various dimensions.
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SAXS examination of the water evaporation process from silica materials coated with a polysaccharide–polyimine copolymer layer
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Modelling and experimental investigation of the phenomenon of brekdown of the liquid layer formed by an impinging two-phase air-water jet
PublicationW pracy przedstawiono analizę teoretyczną i badania eksperymentalne badania zjawiska rozrywania warstwy cieczy powstałej z uderzającej strugi
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Thin layer headspace gas chromatography for biological monitoring of persons exposed to volatile organohalogen compounds from water
PublicationCelem pracy było zbadanie możliwości wykorzystania analizy fazy nadpowierzchniowej nad cienką warstwą cieczy z samoczynną generacją ciekłego sorbentu (TLHS)do izolacji i wzbogacania THM w próbkach moczu i krwi ludzkiej. Umożliwiło to następnie wykorzystanie prostej techniki bezpośredniego nastrzyku próbki do kolumny chromatografu gazowego, wyposażonego w detektor wychwytu elektronów (DAI-GC-ECD).Przy pomocy tak opracowanej metody...
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Solid-Contact pH Sensor without CO2Interference with a Superhydrophobic PEDOT-C14as Solid Contact: The Ultimate “Water Layer” Test
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Experimental research on water lubricated three layer sliding bearing with lubrication grooves in the upper part of the bush and its comparison with a rubber bearing
Publicationcomposite. Eachofitslayershasanimportantfunction.Speciallypreparedslidingsurfaceensures minimum resistance.Followingrunning-initssmoothnessbecomesveryhighandthebearingmay continue workingunder fluid lubricationregime.NBRlayerensuresbearingelasticity,goodvibration damping propertiesandinsusceptibilitytoshaftaxismisalignment.Theexternalbrasslayermakes fitting thebearingeasier. Experiment resultsoftheconductedresearchwerecomparedwiththoseforarubberbearingof similar...
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Improvement of the Water Resistance of a Narrow-Band Red-Emitting SrLiAl3N4:Eu2+Phosphor Synthesized under High Isostatic Pressure through Coating with an Organosilica Layer
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Properties comparison of rubber and three layer PTFE-NBR-bronze water lubricated bearings with lubricating grooves along full bush circumference based on experimental tests
PublicationWater lubricated bearings have been in industrial use for well over a century. During the last decade their traditional range has been expanded with new, modern products. Despite that fact, certain solutions continue to employ the standard rubber bearing with lubricating grooves located along entire bush circumference. The work presents experimental research conducted on comparable sliding bearings with lubrication grooves along...
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Anti-plane shear waves in an elastic strip rigidly attached to an elastic half-space
PublicationWe consider the anti-plane shear waves in a domain consisting of an infinite layer with a thin coating lying on an elastic half-space. The elastic properties of the coating, layer, and half-space are assumed to be different. On the free upper surface we assume the compatibility condition within the Gurtin–Murdoch surface elasticity, whereas at the plane interface we consider perfect contact. For this problem there exist two possible...
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Analysis of the correlation between instantaneous resistance-increase in waves and ship motion for reducing fuel consumption
PublicationReducing fuel consumption is crucial for greening water transport. Wind, waves and currents affect fuel usage, with wave-induced resistance being significant. Typically, added resistance is estimated as the time average of resistance increase in waves over calm water. However, this average lacks real-time utility for engine adjustments. This study analyses time-series correlations between wave-induced resistance-increase and ship...
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Fuzzy Control of Waves Generation in a Towing Tank
PublicationThis paper presents the results of research related to the transformation of electrical energy into potential and kinetic energy of waves generated on the water surface. The waves are generated to model the environmental conditions for the needs of the model tests. The model tests are performed on model-scale objects to predict the features of full-scale maritime objects. It is done to improve human safety and the survivability...
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INVESTIGATION OF BOTTOM SEDIMENT STRATIFICATION
PublicationThe main goal of this paper is to find a method to assess remotely the type of sediments on the basis of the signal received using the parametric echosounder. The images of the sea bottom sediments taken by a parametric echosounder show the fine structure of the upper layer of the bottom sediments. The depth of penetration depends on the type of sediment, in fact on the attenuation of acoustic wave. In the paper the method of distinguishing...
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Negative impact of constant RPM control strategy on ship NOx emission in waves
PublicationIn severe wave conditions, the ship propulsion system is loaded with high fluctuations due to external disturbances. The highly fluctuating loads enforce radical changes in the main engine torque, which in turn demands variation of the fuel rate injected into the cylinders if a constant rotational speed strategy is applied. Therefore, the temperature of gases varies to a large extent during the combustion process in the cylinders....
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Effects of interfacial sliding on anti-plane waves in an elastic plate imperfectly attached to an elastic half-space
PublicationWe study the anti-plane shear waves in a domain consisting of an elastic layer (plate) with a coating attached to an elastic half-space (substrate). We assume an imperfect contact between the layer and the half-space, allowing some sliding. We also assume some elastic bonds between the layer and the substrate. On the free top surface we apply the compatibility conditions within the Gurtin–Murdoch surface elasticity. We found two...
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Underwater Navigation Ssystem Based on Doppler Shift – Measurements and Error Estimations
PublicationA new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected...
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Experiment with small objects floating under water in the harbor security aspect.
PublicationObservation of the underwater area is the element of general trend which primary purpose is to protect and enhance the safety of the selected region. The aim of the paper is to present the acoustic characteristics of typical objects floating on the surface or under the water, which constitute some knowledge on how to detect these objects. Create a catalog of acoustic signatures and acoustic images of objects mostly floating under...
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Metrological analysis of precision of the system of delivering a water capsule for explosive production of water aerosol
PublicationIn this paper an analysis of precision of the system controlling delivery by a helicopter of water-capsule designed for extinguishing large scale fires is presented. The analysis was performed using the numerical method of distribution propagation (Monte Carlo method) supplemented with results of application of the uncertainty propagation method. In addition the optimum conditions for the airdrop are determined to ensure achievement...
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Analiza i ocena smarności olejów w ujęciu energetycznym i działania układu tribologicznego = Analysis and evaluation of oil lubricity from the viewpoint of energy apects and of the tribological system action
PublicationBased on measurement results, an interpretation is presented of the tribological system boundary layer action in the form of a four-ball tester friction node. The evaluation was performed of the boundary layer action understood as transfer of energy Ep resulting from loading the tribological system in a determined time t with work Lp, which may lead to breaking the boundary layer. That energy and time are the values unequivocally...
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The accretion of the new ice layer on the surface of hexagonal ice crystal and the influence of the local electric field on this process
PublicationThe process of creation of a new layer of ice on the basal plane and on the prism plane of a hexagonal ice crystal is analyzed. It is demonstrated that the ordering of water molecules in the already existing crystal affects the freezing. On the basal plane, when the orientations of water molecules in the ice block are random, the arrangement of the new layer in a cubic manner is observed more frequently — approximately 1.7 times...
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Multistatyczny, Dopplerowski System określania położenia i prędkości ruchomych celów w wodzie
PublicationW omawianym w pracy multistatycznym, dopplerowskim systemie określania położenia i prędkości ruchomych celów w wodzie źródłem sygnału są dwa nadajniki emitujące sinusoidalne, akustyczne fale ciągłe o różnych częstotliwościach, które po odbiciu od ruchomego celu są obierane przez cztery hydrofony. W artykule przedstawiono analize teoretyczna efektu Dopplera, na którym oparte jest działanie systemu oraz metodę rozwiązania głównych...
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Insights into the flow characteristics during hydraulic fracturing
PublicationThis paper presents a numerical model to study fracture propagation during water-based hydraulic fracturing. To address the computational challenges associated with the numerical model, the proposed approach employs a set of overlapping spheres arranged in a monolayer to construct a porous specimen containing pre-existing cracks. The fluid-filled cracks represent various stages of initiation and propagation of fluid-driven fracture....
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Desulfurization of raw naphtha cuts using hybrid systems based on acoustic cavitation and advanced oxidation processes (AOPs)
PublicationA combination of dual-frequency acoustic cavitation (acoustic cavitation) and UV assisted advanced oxidation processes (AOPs) reaction system was developed for desulfurization of raw naphtha used to produce aviation fuels. Various types of oxidants in hybrid systems including hydrogen peroxide, acetic acid, acetone, air and ozone were compared. At optimum oxidant to sulfur compounds molar ratio (rox) of 5.0, the hybrid process...
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The effect of multiaxial geocomposite reinforcement on fatigue performance and crack propagation delay in double-layered asphalt beams
PublicationThe presented study investigates the effect of a recently developed multiaxial geocomposite made of polypropylene geogrid and non-woven fabric on the delay of crack propagation, based on four-point bending tests of large asphalt concrete beams – both for reinforced and non-reinforced specimens. Several approaches are described in this study, including analysis of stiffness modulus decrease and analysis of crack propagation using...
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Investigation of Acoustic Properties of Poroelastic Asphalt Mixtures in Laboratory and Field Conditions
PublicationMeasures for the improvement of acoustic conditions in the vicinity of roads include the construction of pavement structures with low-noise surfaces with optimal macrotexture and the highest possible sound absorption coefficient. Laboratory evaluation of acoustic properties of a designed asphalt mixture before its placement in the pavement is a good solution. Currently, the most popular method for the determination of the sound...
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Water sorption and blistering of GFRP laminates with varying structures
PublicationThe microstructures, water absorption as well as blistering was studied for bi- and tri- axial glass fibre vinyl ester and polyester -matrix laminates coated with gel coat layer and uncoated. The effect of manufacturing technique on water sorption characteristics was considered. It was found that water sorption characteristics of GFRP depend on manufacturing methods. The least water intake was found for specimens having perfect...
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Approximate solution for Euler equations of stratified water via numerical solution of coupled KdV system
PublicationWe consider Euler equations with stratified background state that is valid for internal water waves. The solution of the initial-boundary problem for Boussinesq approximation in the waveguide mode is presented in terms of the stream function. The orthogonal eigenfunctions describe a vertical shape of the internal wave modes and satisfy a Sturm-Liouville problem. The horizontal profile is defined by a coupled KdV system which is...
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Sea bottom structure investigation by means of acoustic methods
PublicationThe main aim of the paper is the result of experimental investigations of the seabed in the Gulf of Gdańsk arried out using parametric echosounder as a main measuring tool. Examination of the surface's upper layer of the seabed, especially is acoustic properties, reflecting most often transsmision and reflection properties of the incident elastic wave, could be a valuable material for determination of the stratification, and the...