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Wyniki wyszukiwania dla: microstructure contact problems size effects boundary layers cosserat continuum
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Thermo-resonance analysis of an excited graphene sheet using a new approach
PublikacjaForced vibration of graphene nanoplate based on a refined plate theory in conjunction with higher-order nonlocal strain gradient theory in the thermal environment has been investigated. Regarding the higher-order nonlocal strain gradient theory, both stress nonlocality and size-dependent effects are taken into account, so the equilibrium equations which are governing on the graphene sheet have been formulated by the theory....
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An Influence of Factors of Flow Condition, Particle and Material Properties on Slurry Erosion Resistance
PublikacjaThe degradation of materials due to slurry erosion is the serious problem which occurs in the power industries. The paper presents actual knowledge about an influence of individual factors connected with flow conditions, particles and material properties on the slurry erosion resistance. Among the factors connected with operating conditions, an influence of impact angle, and velocity of impact, particle concertation and liquid...
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The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study
PublikacjaBackground: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). Material and Methods: In CBCTs, the effect of impacted third molars on the root surface of adjacent second...
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Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes
PublikacjaFlow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighboring nodes or cells of the numerical...
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Decontaminating Arbitrary Graphs by Mobile Agents: a Survey
PublikacjaA team of mobile agents starting from homebases need to visit and clean all nodes of the network. The goal is to find a strategy, which would be optimal in the sense of the number of needed entities, the number of moves performed by them or the completion time of the strategy. Currently, the field of distributed graph searching by a team of mobile agents is rapidly expanding and many new approaches and models are being presented...
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A facile approach to fabricate load-bearing porous polymer scaffolds for bone tissue engineering
PublikacjaBiodegradable porous scaffolds with oriented interconnected pores and high mechanical are load-bearing biomaterials for bone tissue engineering. Herein, we report a simple, non-toxic, and cost-effective method to fabricate high-strength porous biodegradable scaffolds, composed of a polymer matrix of polycaprolactone (PCL) and water-soluble poly (ethylene oxide) (PEO) as a sacrificial material by integrating annealing treatment,...
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Temperature Evolution, Material Flow, and Resulting Mechanical Properties as a Function of Tool Geometry during Friction Stir Welding of AA6082
PublikacjaThe friction stir welding process was simulated for joining AA6082 aluminum alloy with the use of the computational fluid dynamics method. Two different tool geometries were used—a tapered cylindrical pin (simple pin) and a hexagonal pin with grooves (complex pin). The analysis of the simulations performed was discussed in terms of temperature evolution during the process, total heat input, residual stresses and material flow....
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On time-dependent nonlinear dynamic response of micro-elastic solids
PublikacjaA new approach to the mechanical response of micro-mechanic problems is presented using the modified couple stress theory. This model captured micro-turns due to micro-particles' rotations which could be essential for microstructural materials and/or at small scales. In a micro media based on the small rotations, sub-particles can also turn except the whole domain rotation. However, this framework is competent for a static medium....
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Degradation of a nano-cutting tool: an MD simulation
PublikacjaW pracy przedstawiono wyniki symulacji wielokrotnego oddziaływania realistycznie ukształtowanego ostrza tnącego z modelowym, nieskończenie twardym ziarnem, przy zastosowaniu metody dynamiki molekularnej. Ostrze składało się z kilkuset tysięcy atomów metalu fcc, traktowanego za pomocą potencjału Suttona-Chena, przesuwane było ze stałą prędkością 20 m/s. Obserwowane deformacje plastyczne pojawiające się na skutek kontaktu ostrza...
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Aquaponics Based Artificial Biosphere Included in Architecture: From Mitigation of Negative Impacts to Positive Added Values of Urban Spatial Structures on Local, Regional and Global Scale
PublikacjaTechnologies may appear faster than spatial planning can afford it. Alt hough applying new technologies solve particular problems, it may also create new ones. Many negative consequences of implementing new technologies are visible a fter years or decades – they accumulate until the need of solving them. According to The Hannover Principles (McDonough & Braungart 2013) one should, by example not think about...
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Coffee Silverskin as a Multifunctional Waste Filler for High-Density Polyethylene Green Composites
PublikacjaThis work aims to describe the coffee silverskin effect as a lignocellulosic waste filler for high-density polyethylene (HDPE) composites development. The main task was to determine various modification effects resulting from the complex chemical composition of coffee silverskin containing compounds with potential antioxidative properties, including caffeine, polyphenols, tannins, or melanoidins. The processing, thermal, physicochemical,...
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Driverless Mobility: The Impact on Metropolitan Spatial Structures
PublikacjaDiffusion of emerging technologies is following the need of solving particular problems. Each innovation produce also some undesirable consequences. Many examples from the past have shown that along with the spread of each technology their side effects are accumulating until the level they need to be solved. One of the examples is automobile, which advantages and disadvantages were already described including its spatial consequences....
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Designing a high-sensitivity dual-band nano-biosensor based on petahertz MTMs to provide a perfect absorber for early-stage non-melanoma skin cancer diagnostic
PublikacjaThe purpose of this study is development of a novel high-performance low-Petahertz (PHz) biosensor for non-melanoma skin cancer (NMSC) diagnosis. The presented device is designed to work within a microwave imaging regime, which is a promising alternative to conventional diagnostic methods such as visual examination, dermoscopy, and biopsy. The suggested biosensor incorporates a dual-band perfect absorber (operating bands at 0.909...
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Tailoring of Optical Properties of Methacrylate Resins Enriched by HPHT Microdiamond Particles
PublikacjaDiamond particles have great potential to enhance the mechanical, optical, and thermal properties of diamond–polymer composites. However, the improved properties of diamond–polymer composites depend on the size, dispersibility, and concentration of diamond particles. In the present study, diamond–polymer composites were prepared by adding the microdiamond particles (MDPs) with different concentrations (0.2–1 wt.%) into polymers...
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Effect of asymmetric fluid flow distribution on flow boiling in a microchannel heat sink – An experimental investigation
PublikacjaFlow boiling in microchannels is emerging as an exclusive cooling solution for miniaturized high-power electronic devices alongside having other high heat flux applications. Size miniaturization at microscale strangely increases heat transfer performance as well as flow boiling instabilities. Many flow boiling instabilities are interrelated and result from imperfect hydrodynamic conditions. One of such problems is flow maldistribution among...
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IS SMALLER BETTER? THE VALUATION OF SOCIAL IMPACTS OF DIFFERENTLY SIZED SPORTING EVENTS. THE CASE OF GDAŃSK
PublikacjaIntroduction. There is a discourse in the international literature regarding the impact of large sporting events on the place where they are held. In the last few years, particular emphasis has been laid on intangible effects, including social impacts that may occur not only in the case of mega sporting events but also in smaller sporting events. Therefore, the main aim of this paper is to estimate the monetary value of intangible...
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Pounding Between Superstructure Segments in Multi-Supported Elevated Bridge with Three-Span Continuous Deck Under 3D Non-Uniform Earthquake Excitation
PublikacjaReports after severe ground motions show that the earthquake-induced structural pounding may lead to significant damage in elevated bridges. The aim of this paper is to analyse pounding between superstructure segments of a highway elevated bridge with three-span continuous deck under 3D non-uniform earthquake excitation, which is induced by spatial seismic effects related to the propagation of seismic wave. The conditional stochastic...
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The Effectiveness of Rubber Bumpers in Reducing the Effects of Earthquake-Induced Pounding between Base-Isolated Buildings
PublikacjaTh e methods for preventing earthquake-induced structural pounding between two adjacent buildings include ensuring a sufficient separation distance between them or decreasing their relative displacement during seismic excitation. Some equations or even specific values of such gap sizes between two buildings have been introduced so as to avoid collisions. Increasing the stiffness of buildings, using tuned mass dampers, applying...
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Detoxification of the tricyclic antidepressant opipramol and its analog – IS-noh by UGT enzymes before and after activation by phase I enzymes in rat liver microsomes
PublikacjaThe present studies were carried out to evaluate the simultaneous one-pot metabolism of opipramol (IS-opi) and analog (IS-noh) by phase I and phase II enzymes present in rat liver microsomes (RLM) as an alternative to separate testing with recombinant enzymes. This approach allows for more time-saving and cost-effective screening of the metabolism of newly discovered drugs. We also considered that the lack of results for phase...
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On Tradeoffs Between Width- and Fill-like Graph Parameters
PublikacjaIn this work we consider two two-criteria optimization problems: given an input graph, the goal is to find its interval (or chordal) supergraph that minimizes the number of edges and its clique number simultaneously. For the interval supergraph, the problem can be restated as simultaneous minimization of the path width pw(G) and the profile p(G) of the input graph G. We prove that for an arbitrary graph G and an integer t ∈ {1,...
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Microgrinding with single-disk lapping kinematics.
PublikacjaGrinding operations are carried out with a variety of tool-workpiece configurations. The selection of a grinding process for a particular application depends on part shape, part size, ease of fixture, requirements concerning the acceptable shape errors. It is evident that lapping is very effective in eliminating the waviness while surface grinding is not. Dual disk machines for the double face grinding with planetary kinematics...
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Analysis of cyclone separator solutions depending on spray ejector condenser conditions
PublikacjaThe core design strategy for minimizing CO2 emissions in gas power plant entails combining a spray ejector condenser (SEC) and separator to accomplish steam condensation and CO2 purification. This innovative process involves direct-contact condensation of steam with CO2, facilitated by interaction with a subcooled water spray, along with a cyclone separator mechanism intended for generating pure CO2. The investigation of the SEC...
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High-Temperature Oxidation of Heavy Boron-Doped Diamond Electrodes: Microstructural and Electrochemical Performance Modification
PublikacjaIn this work, we reveal in detail the effects of high-temperature treatment in air at 600 °C on the microstructure as well as the physico-chemical and electrochemical properties of boron-doped diamond (BDD) electrodes. The thermal treatment of freshly grown BDD electrodes was applied, resulting in permanent structural modifications of surface depending on the exposure time. High temperature affects material corrosion, inducing...
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Modele i algorytmy dla grafowych struktur defensywnych
PublikacjaW niniejszej pracy przeprowadzono analizę złożoności istnienia struktur defensywnych oraz równowag strategicznych w grafach. W przypadku struktur defensywnych badano modele koalicji defensywnych, zbiorów defensywnych i koalicji krawędziowych – każdy z nich w wersji globalnej, tj. z wymogiem dominacji całego grafu. W przypadku modeli równowagi strategicznej badano równowagę strategiczną koalicji defensywnych, równowagę strategiczną...
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Prediction of coking dynamics for wet coal charge
PublikacjaA one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal...
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Stress Monitoring System for Individuals with Autism Spectrum Disorders
PublikacjaIn this article, a stress monitoring system tailored for individuals with Autism Spectrum Disorders (ASD) and developed for the educational institution is presented. People with ASD face problems with effective stress management due to their high self-perceived levels of stress, poor ability to cope with it, and dificulties with the accurate detection of the source of stress. Consistently, being able to measure stress appears to...
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Nutrient transport and acquisition by diatom chains in a moving fluid
PublikacjaThe role of fluid motion in delivery of nutrients to phytoplankton cells is a fundamental question in biological and chemical oceanography. In the study of mass transfer to phytoplankton, diatoms are of particular interest. They are non-motile, are often the most abundant components in aggregates and often form chains, so they are the ones expected to benefit most from enhancement of nutrient flux due to dissipating turbulence....
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Multimodal Particle Swarm Optimization with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublikacjaIn this paper, a new meta-heuristic method of finding roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of the complex function. The method initially generates two uniformly distributed populations of particles on the complex...
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A Survey of Vehicular Network Systems for Road Traffic Management
PublikacjaIn this survey, we analyze the proposals of vehicular communication systems in the context of road traffic management. Starting with the definition of communications between vehicles (V2V), vehicles-to-infrastructure (V2I) and vehicles-to-everything (V2X), we first focus on the requirements and current standards for the Intelligent Transport Systems (ITS), including the maximum communication delay, the communication range and the...
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Interventions reducing car usage: Systematic review and meta-analysis
PublikacjaThis systematic literature review aimed to investigate the extent to which transport-related interventions induced a reduction in car use. Both qualitative synthesis and meta-analysis were employed. The synthesis included 31 original studies, while the meta-analysis included 21. Of the qualitatively synthesised studies, 74 % demonstrated that interventions were effective in reducing car use. The pooled estimates of the effects...
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Quantum Steering Inequality with Tolerance for Measurement-Setting Errors: Experimentally Feasible Signature of Unbounded Violation
Publikacjauantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence — steer — Bob ’ s physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size,...
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Effect of Microplastics Pollution on Hydrogen Production from Biomass: A Comprehensive Review
PublikacjaHydrogen production from biomass and organic wastes is considered as a potential alternative energy source and is known as a clean and CO2-free fuel energy carrier. H2 is considered very promising among the other energy sources; therefore, the effective conversion of biomass and organic solid waste to this secondary energy source is urgently sought. As a result, it is of importance to assess the impact of the existence of microplastics...
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Research on the effect of low-sulphur marine fuels on the dynamic characteristics of a CI engine
PublikacjaThe implementation of low-sulphur, so-called modified marine fuels into operation requires prior labora- tory engine tests to assess the energy, emission and structural effects of their usage. This type of research are carried out on the test bed of a diesel engine as a small-scale physical model that reproduces the adequate design and process (parametric) features of a full-size marine engine. Their key stage is to determine the energy...
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Prenatal exposure to substance of abuse: A worldwide problem
PublikacjaSubstance abuse during pregnancy is an important public health issue affecting the mother and the growing infant. Preterm labor, miscarriage, abruption and postpartum hemorrhage are obstetric complications which have been associated with women who are dependent on abused substances. Moreover, women are also at an increased risk of medical problems such as poor nutrition, anemia, urinary tract infections as well as sexually transmitted...
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Millimeter Wave Negative Refractive Index Metamaterial Antenna Array
PublikacjaIn this paper, a novel negative refractive index metamaterial (NIM) is developed and characterized. The proposed metamaterial exhibits negative effective permittivity (εeffe) and negative effective permeability (µeffe) at millimeter wave frequency of 28GHz. This attractive feature is utilized to enhance the gain of a microstrip patch antenna (MPA). Two thin layers of 5 5 subwavelength unit cell array of NIM are placed above a...
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Nanostructuring of thin Au films deposited on ordered Ti templates for applications in SERS
PublikacjaIn this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid...
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Nanoparticles preparation using microemulsion systems
PublikacjaMetallic nanoparticles become of current interests because they exhibit unique properties compared with those of metal atoms or bulk metal due to the quantum size effect and their large surface area, which make them attractive for applications in optics, electronics, catalysis biology and medicine. TiO2 has been used for environmental remediation purposes such as in the purification of water and air and also solar-to chemical energy...
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Selected local stability problems of channel section flanges made of aluminium alloys
PublikacjaThe paper addresses the issue of local buckling of compressed flanges of cold-formed thin-walled channel columns and beams with nonstandard flanges composed of aluminium alloys. The material behaviour follows the Ramberg–Osgood law. It should be noted that the proposed solution may be also applied for other materials, for example: stainless steel, carbon steel. The paper is motivated by an increasing interest in nonstandard cold-formed...
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Seismic damage diagnosis in adjacent steel and RC MRFs considering pounding effects through improved wavelet-based damage-sensitive feature
PublikacjaThis paper aims to propose complex Morlet (cmorfb-fc) wavelet-based refined damage-sensitive feature (rDSF) as a new and more precise damage indicator to diagnose seismic damages in adjacent steel and Reinforced Concrete (RC) Moment Resisting Frames (MRFs) assuming pounding conditions using acceleration responses. The considered structures include 6- and 9-story steel and 4- and 8-story RC benchmark MRFs that are assumed to have...
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Preparation and characterization of natural rubber composites highly filled with brewers' spent grain/ground tire rubber hybrid reinforcement
PublikacjaBrewers' spent grain (BSG) and ground tire rubber (GTR) were applied as low-cost hybrid reinforcement natural rubber (NR). The impact of BSG/GTR ratio (in range: 100/0, 75/25, 50/50, 25/75 and 0/100 phr) on processing and performance properties of highly filled natural rubber composites was evaluated by oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy,...
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Improvement of glass break acoustic signal detection via application of wavelet packet decomposition
PublikacjaThe main subject of the authors' research are non-contact methods of glass break detection based on analysis of the acoustic signal generated during the event. This problem has essential meaning for modern cost- effective alarm systems, particularly those installed into big buildings. The main difficulties of the matter are: transient character of the signal, great number of similar sounds (false signals, mainly accidental glass...
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System monitoringu odbieraków prądu pojazdów kolejowych w aspekcie bezpieczeństwa i ciągłości ruchu.
PublikacjaOmówiono metodę monitorowania stanu technicznego odbieraków prądu w oparciu o pomiar uniesienia przewodów jezdnych sieci trakcyjnej w czasie przejazdu pociągu. Opisano konstrukcję i zasadę działania wdrożonego na linii kolejowej pilotażowego stanowiska monitoringu. Przedstawiono metodę analizy i sposób wizualizacji wyników pomiarów. Zastosowany algorytm szacowania siły statycznej odbieraka uwzględnia prędkości pociągu i działanie...
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Positive management of the university
PublikacjaAbstract: The prevailing view held at contemporary Polish universities is that their main goal is to achieve effects measured by indicators, which applies to each element of their mission: education, research and the third mission, whereas the means to accomplish this goal consists of increasing the requirements and motivating by the “carrot and stick” approach. That approach discounts the importance of building a positive relationship...
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METHODS OF TEACHING NOISE PROTECTION AT ENVIRONMENTAL ENGINEERING
PublikacjaNoise strongly influences both our health and behavior in everyday life and as employees or employers. The lost of hearing and other effects of noise on humans result not only in a significant decrease in the quality of life or work efficiency but have also have economic consequences. As noise can be preventable in part by the Environmental Engineers, but it is necessary to introduce them noise issues during their education process....
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Transformation of the Odesa Waterfront
PublikacjaOdesa is a unique city: it is the third-largest city in Ukraine and the second in the Black sea region. During its short but eventful history, it gathered a variety of cultural layers within its boundaries, what had reflected in its architecture, urban life, and unique accent of its inhabitants. The city`s waterfront is considered to be the Pearl of the Black Sea. Starting with the receiving of the Porto Franco status in 1819,...
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On the compression of multibeam sonar raw bathymetry data
PublikacjaMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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Using wavelet techniques for multibeam sonar bathymetry data compression
PublikacjaMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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Effects of deviations from thermo-rheologically simple behavior of asphalt mixes in creep on developing of master curves of their stiffness modulus
PublikacjaThe paper presents the deviations from the thermo-rheologically simple behavior of asphalt mixes and their effects on the developing of master curves of stiffness modulus. Eleven different mixes were tested in three point bending test under constant load at temperatures –20°C, –10 °C and 0 °C, and in some cases at +10 °C. The test method was developed at the Gdansk University of Technology, Poland. The applied stress level was...
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X-Ray Computer Tomography Study of Degradation of the Zircaloy-2 Tubes Oxidized at High Temperatures
PublikacjaThe investigations of high-temperature oxidation of zirconium alloys, applied for fuel pellets in nuclear power plants, are usually limited to oxidation kinetics, phase transformations and microstructural characterization. The purpose of this research was to characterize the degradation phenomena occurring within oxide layer and at the interface oxide/metal, on internal and external Zircaloy-2 tube...
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Influence of Surface Modification of Titanium and Its Alloys for Medical Implants on Their Corrosion Behavior
PublikacjaTitanium and its alloys are often used for long-term implants after their surface treatment. Such surface modification is usually performed to improve biological properties but seldom to increase corrosion resistance. This paper presents research results performed on such metallic materials modified by a variety of techniques: direct voltage anodic oxidation in the presence of fluorides, micro-arc oxidation (MAO), pulse laser treatment,...