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Search results for: FRACTURE TOUGHNESS, ORTHOGONAL CUTTING, CUTTING FORCE, CUTTING POWER, FRAME SAWING, PINE WOOD
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Simplified AutoDock force field for hydrated binding sites
Publicationhas been extracted from the Protein Data Bank and used to test and recalibrate AutoDock force field. Since for some binding sites water molecules are crucial for bridging the receptor-ligand interactions, they have to be included in the analysis. To simplify the process of incorporating water molecules into the binding sites and make it less ambiguous, new simple water model was created. After recalibration of the force field on...
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Relationship between saw blade teeth wear and kinematics of frame sawingmachines
PublicationPrzedstawiono rezultaty badań zużycia ostrzy pił trakowych i wpływ kinematyki pilarki ramowej na rozkład zużycia poszczególnych ostrzy pił.
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublicationIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Homoclinics for singular strong force Lagrangian systems
PublicationWe study the existence of homoclinic solutions for a class of generalized Lagrangian systems in the plane, with a C1-smooth potential with a single well of infinite depth at a point ξ and a unique strict global maximum 0 at the origin.Under a strong force condition around the singular point ξ, via minimization of an action integral, we will prove the existence of at least two geometrically distinct homoclinic solutions.
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Praca z drewnem - Przestrzeń eksperymentu w tworzeniu architektury; Crafting Wood - Space of experiment in making architecture
PublicationW artykule przedstawiono eksperymenty z materiałem w tworzeniu architektury prowadzące do praktycznych rozwiązań w konstrukcji budynku. Takie podejście do tematyki zastosowania materiałów w architekturze nakreśla praktyczne aspekty tworzenia przestrzeni podczas pracy np. z drewnem. Podejście przedstawiono w kontekście dziedzictwa kulturowego podczas intensywnych warsztatów dotyczących tradycji i kultury budownictwa wybranych regionów...
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Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
PublicationThe aim of the present paper is to show the results of the shaking table experimental study concerning the diagnosis of damage in a model of cylindrical steel tank with self-supported roof which is filled with liquid. During the tests, the base of the structure was excited under the harmonic loading with variable frequency. The tests were repeated for different stages of damage, which was introduced in the model by easing the bolts...
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Two-dimensional simulations of concrete fracture at aggregate level with cohesive elements based on X-ray lCT images
PublicationThe paper presents results of two-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 4-phase material composed of aggregate grains placed in the cement matrix, interfacial transitional zones (ITZs) and macro-voids. The particle distribution was taken from real concrete beams on the basis of X-ray lCT images. Comprehensive numerical analyses were carried...
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Spatial variability of throughfall in a stand of Scots pine (Pinus sylvestris L.) with deciduous admixture as influenced by canopy cover and stem distance
PublicationVegetation cover affects the amount of precipitation, its chemical composition and its spatial distribution, and this may have implications for the distribution of water, nutrients and contaminants in the subsurface soil layer. The aim of this study was a detailed diagnosis of the spatio-temporal variability in the amount of throughfall (TF) and its chemical components in a 72-year-old pine stand with an admixture of oak and birch....
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Problems in estimation of hand grip force based on EMG signal
PublicationThere has recently been a significant increase in the number of publications on and applications of bioelectric signals for diagnostic purposes. While the use of ECG (electrocardiography) is not surprising, the use of signals from registration of brain activity (EEG) and muscles activity (EMG) still finds new applications in various fields. The authors focus on the use of EMG signals for estimating hand grip force. Currently,...
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Triplet Formation and Triplet‐Triplet Annihilation Upconversion in Iodine Substituted Non‐Orthogonal BODIPY‐Perylene Dyads
PublicationBODIPY-perylene dyads have emerged as useful metal free sensitizers for triplet-triplet annihilation upconversion (TTAUC), these dyads are capable of efficient triplet generation via spinorbit charge transfer intersystem crossing (SOCT-ISC). This important route to triplet formation requires dyads in which two moieties are oriented perpendicular to each other. In this contribution, we give a deeper insight on the behavior of recently...
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The effect of thermal modification of ash wood on granularity and homogeneity of sawdust in the sawing process on a sash gang saw PRW 15-M in view of its technological usefulness
PublicationPrzedstawiono wyniki analiz granulometrycznych trocin, drewna jesionowego niemodyfikowanego (Fraxinus exelsior L.) i modyfikowanego termicznie, otrzymanych w procesie przecinania drewna na pilarce ramowej wielopiłowej PRW15-M. Przecinanie drewna prowadzono dla dwu prędkości posuwu 0,36 m·min-1 oraz 1,67 m·min-1. Ziarnistośćpowstających trocin dla drewna jesionowego modyfikowanego termicznie zawierała się w przedziale od 33,5 μm...
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SEM micrographs and photos of salivary gland stones
Open Research DataThis dataset contains SEM micrographs and high-resolution photographs taken for salivary gland stones (sialolith) extracted during joint studies between Medical University of Gdansk and Gdansk University of Technology.
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Review of the Air Force Academy
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Michał Michna dr hab. inż.
PeopleMichal Michna received the M.Sc. and Ph.D. degrees in electrical engineering from the Gdansk University of Technology (GUT), Gdansk, Poland, in 1998 and 2005, respectively. Since 2004, he was employed at the Department of Power Electronics and Electrical Machines of the Gdańsk University of Technology (assistant, assistant professor, senior lecturer). In 2010-2015 he was a deputy of head of the Department of Power Electronics and...
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TIME-AND-SPACE STRUCTURE OF FORCE-DRIVEN RIGID SPHEREWAVEFIELD
PublicationThis paper introduces a time-domain, causality-inspired description of a vector-source acoustic wavefield of arbitrary time evolution, where a sphere is a practical realisation of quasi-point contact surface without which a point force would not be able to exert an impact onto non-viscous fluid. At every space location, the resulting acoustic field is described by a pair of physical variables characterising the time evolution of...
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Simulation of wood structure geometry after machining
PublicationW niniejszym artykule została przedstawiona nowa metoda trójwymiarowych symulacji geometrii powierzchni drewna. Zaprezentowano wpływ parametrów obróbkowych oraz drgań podczas strugania obrotowego drewna. Chropowatość powierzchni była charakteryzowana poprzez parametry profilu chropowatości Ra oraz Rz. Posuw na ostrze oraz średnica narzędzia są najbardziej wpływającymi czynnikami na wielkość nierówności podczas maszynowej obróbki...
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Power Hardware-in-the-Loop Approach In Power System Development
PublicationThe main objective of the research is the verification of the Power Hardware-In-The-Loop (PHIL) approach in power system analysis and design. The premise of the article is that using PHIL approach the performance of the power system in steady and transient state conditions can be analysed in real power system conditions. Models of induction machine were developed and real time simulations were performed. Simulation variables were...
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Activated Carbon Produced by Pyrolysis of Waste Wood and Straw for PotentialWastewater Adsorption
PublicationPyrolysis of straw pellets and wood strips was performed in a fixed bed reactor. The chars, solid products of thermal degradation, were used as potential materials for activated carbon production. Chemical and physical activation processes were used to compare properties of the products. The chemical activation agent KOH was chosen and the physical activation was conducted with steam and carbon dioxide as oxidising gases. The eect...
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The fracture behaviour of notched PMMA specimens under simple loading conditions – Tension and torsion experimental tests
PublicationThis paper presents the results of experimental testing of flat PMMA specimens during uniaxial loading conditions. Two separate tests were conducted: tensile and torsion. The specimens were weakened with V-type edge notches with different root radii: 0.5; 2 and 10 mm. The specimens were made in two thickness variants: 5 and 15 mm. Monotonic tensile and torsion tests were carried out while keeping the averaged strain rate constant,...
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Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer Composites
PublicationRecent reports in the literature have shown that fber-reinforced geopolymer composites (FRGC) made with monofbers exhibit a signifcant enhancement in fracture energy. However, many aspects of the fracture performance of hybrid fberreinforced geopolymer composites (HFRGC) remain largely unexploited, and these are predominant for the structures. For the frst time, the mode I fracture energy of HFRGC is investigated. The mode I behavior...
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Fracture surface topography investigation and fatigue life assessment of notched austenitic steel specimens
PublicationThe objectives of this study were to investigate the fracture surface topography of X8CrNiS18-9 austenitic stainless-steel specimens for different loadings and notch radii and to supplement the knowledge about the fracture mechanisms for fatigue performance. Cases with three different values of the notch radius ρ and the stress amplitude σa were analysed. The fracture topographies were quantified by the areas over their entire...
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POWER EFFICIENCY OF POWER PLANTS ON TRAILING SUCTION HOPPER DREDGERS
PublicationThis paper presents the notion of operational power efficiency and compares it with the classical definition of power efficiency. There are presented also calculation results of power efficiency for a selected suction hopper dredger and also influence of power system type of suction hopper dredger on magnitude of power efficiency of its power plant has been highlighted.
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Structures of diamond tool composites
PublicationPresented are structures and examples of applications of diamond tool composites. They are widely used as cutting tools, bonded abrasive tools and dressing tools.
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Deformation and Surface Color Changes of Beech and Oak Wood Lamellas Resulting from the Drying Process
PublicationThe drying process was examined relative to parameters’ influence on the deformation and surface layer color changes of beech wood (Fagus sylvatica L.) and oak wood (Quercus robur L.). The goal was to analyze the impact of drying process conditions, wood and growth rings types, and load on the deformation and surface color changes of drying thin wooden elements. A further aim was to reduce the time of the lamella drying and minimize...
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POWER
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Soliton trapping and orthogonal Raman scattering in a birefringent photonic crystal fiber
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Internal imaging of concrete fracture based on elastic waves and ultrasound computed tomography
PublicationThe condition assessment of concrete structures belongs to the greatest challenges of non-destructive testing. Monitoring the fracture process of concrete and detecting cracks at the earliest possible stage is a vital aspect to ensure the safety of civil engineering objects. The use of ultrasound tomography enables imaging the internal structure of a tested element. This study aims at the visualization of fracture damage in concrete...
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Sorption of ammonia nitrogen and phosphate phosphorous by straw and wood-derived biochars
Open Research DataThis dataset comprises the results of NH4-N and PO4-P sorption kinetics using straw and wood biochars that were pyrolyzed at 450 degrees Celsius. The adsorption capacity (mg/g) and equilibrium concentration (mg/L) are calculated.
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API 5L X65 steel - CMOD-force record in -10°C, along rolling direction
Open Research DataSteel designated as API 5L X65 is often used for oil and gas transportation pipelines. It is caused due to its high ductility, weldability and good corrosion resistance. API 5L X65 is a low alloy steel with carbon content less than 0.3% (depends on delivery condition). Once installed, a pipeline remains in place for many years. Throughout its life,...
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API 5L X65 steel - CMOD-force record in -10°C, across rolling direction
Open Research DataSteel designated as API 5L X65 is often used for oil and gas transportation pipelines. It is caused due to its high ductility, weldability and good corrosion resistance. API 5L X65 is a low alloy steel with carbon content less than 0.3% (depends on delivery condition). Once installed, a pipeline remains in place for many years. Throughout its life,...
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Window frame integrable air recuperation minichannel/minigap heat exchanger
PublicationThis article describes an evaluation of mini heat exchangers operation as a decentralized mechanical ventilation system with recuperative heat recovery that can be integrated into the window frame. The relatively small yet efficient air recuperation system allows for retrofitting existing buildings by reducing the overall energy consumption and thus the CO2 emissions. The proposed design, unlike existing systems, is easy to scale...
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Load introduction to composite columns revisited—Significance of force allocation and shear connection stiffness
PublicationThe AISC 360-16 Specification recommends that the design shear force between parts of a composite column in the load introduction area shall be calculated based on the force allocation at ultimate limit state. Applicability of this straightforward method to the load levels that usually arise in slender composite columns is questionable, as this capacity-based force allocation is only true when the axial force is equal to the plastic...
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WOOD AND FIBER SCIENCE
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Fast Re-Design of Multi-Band Antennas by Means of Orthogonal-Direction Geometry Scaling and Local Parameter Tuning
PublicationApplication-driven design of antenna systems fosters a reuse of structures that have proven competitive in terms of their electrical and field performance, yet have to be re-designed for a new application area. In practice, it most often entails relocation of the operating frequencies or bandwidths, which is an intricate endeavor, normally requiring utilization of numerical optimization techniques. If the center frequencies of...
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Dynamic Nanoimpedance Characterization of the Atomic Force Microscope Tip-Surface Contact
PublicationNanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To...
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Identification of residual force in static load tests on instrumented screw displacement piles
PublicationOccurrence of the so-called residual force of an unknown value significantly disturbs interpretation of static load tests performed on piles equipped with additional measuring instruments. Screw displacement piles are the piling technology in which the residual force phenomenon is very common. Its formation mechanism is closely related to the installation method of this type of piles, which initiates generation of negative pile...
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Effect of bending-torsion on fracture and fatigue life for 18Ni300 steel specimens produced by SLM
PublicationIn this study, different fracture surfaces caused by fatigue failure were generated from 18Ni300 steel produced by selective laser melting (SLM). Hollow round bars with a transverse hole were tested under bending-torsion to investigate the crack initiation mechanisms and fatigue life. Next, the post-failure fracture surfaces were examined by optical profilometer and scanning electron microscope. The focus is placed on the relationship...
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The topography of various sialoliths by scanning electron microscopy
Open Research DataThis dataset contains SEM micrographs taken for salivary gland stones (sialolith) extracted during joint studies between the Medical University of Gdansk and Gdansk University of Technology. Three different types of stones were examined, as discussed in the article: 10.1111/odi.13708
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Implementation of the EVRF2007 height reference frame in Poland
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Losses and raw material yield of wood saeing processes
PublicationW artykule opisano sposób wyznaczania bezwzględnych i względnych strat materiałowych, jak również wydajności materiałowej w procesie przecinania drewna.
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Application of gas-steam mixture for wood drying purposes
PublicationW artykule przedstawiono wyniki suszenia drewna przy zastosowaniu mieszaniny parowo-gazowej. Badania dotyczyły suszenia drewna dębowego, sosnowego i świerkowego. We wszystkich eksperymentach skrócono czas suszenia w porównaniu z suszeniem konwencjonalnym.
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Chip suction system in circular sawing machine: empirical research and computational fluid dynamics numerical simulations
PublicationThe experimental analysis of the wood chip removing system during its redesigning in the existing sliding table circular saw and computational fluid dynamic (CFD) numerical simulations of the air flow process is presented in the paper. The attention was focused on the extraction hood and the bottom shelter of the actual existing system. The main aim was to perform experimental research on the pressure distribution inside the...
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Enhancing capabilities of Atomic Force Microscopy by tip motion harmonics analysis
PublicationMotion of a tip used in an atomic force microscope can be described by the Lennard-Jones potential, approximated by the van der Waals force in a long-range interaction. Here we present a general framework of approximation of the tip motion by adding three terms of Taylor series what results in non-zero harmonics in an output signal. We have worked out a measurement system which allows recording of an excitation tip signal and its...
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Determination of phenylbutazone, sulfamethazine, carbendazim and linuron using a novel pine bark biosorbent for solid-phase extraction (SPE) with high-performance liquid chromatography (HPLC)
PublicationThe paper presents a novel pine bark based biosorbent for solid-phase extraction (SPE). The morphology and composition of the pine bark were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The biosorbent was used for the preparation of wastewater for the determination of phenylbutazone, sulfamethazine, carbendazim, and linuron by high performance liquid chromatography with...
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Tool Wear Monitoring Using Improved Dragonfly Optimization Algorithm and Deep Belief Network
PublicationIn recent decades, tool wear monitoring has played a crucial role in the improvement of industrial production quality and efficiency. In the machining process, it is important to predict both tool cost and life, and to reduce the equipment downtime. The conventional methods need enormous quantities of human resources and expert skills to achieve precise tool wear information. To automatically identify the tool wear types, deep...
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Multiple reference frame theory in the synchronous generator model considering harmonic distortions caused by nonuniform pole shoe saturation
PublicationThe paper describes a synchronous generator model developed based on the multiple reference frame theory. The main physical phenomena included in the model are the machine armature non-sinusoidal voltage waveform and the influence of armature current in load conditions on the armature voltage waveform higher harmonic components. The modified multiple reference frame theory model is proposed. In this modified theory model the field...
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Modelling of power electronic compensators for the analysis of power system operation
PublicationThe article presents selected methods of modelling power electronic compensators in order to analyze their operation in the power systems. Advantages and disadvantages of models have been shown with an indication of their usefulness for modelling specific phenomena.
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Fracture susceptibility of high RAP content asphalt concrete in terms of aging
PublicationDue to the reduction of CO2 emissions during the production of asphalt mixtures and the decrease in the demand for mineral resources, the addition of reclaimed asphalt pavement (RAP) is becoming indispensable. The durability of asphalt pavements containing a high RAP content may be reduced due to a decrease in the cracking resistance of the material, especially under the influence of operational aging. The article presents the...
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Numerical simulation of asphalt mixtures fracture using continuum models
PublicationThe paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasicontinuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate...
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Robert Bogdanowicz dr hab. inż.
PeopleRobert Bogdanowicz received his Ph.D. degree with honours in Electronics from the Gdansk University of Technology. He worked as a post-doc researcher in Ernst-Moritz-Arndt-Universität Greifswald Institut für Physik. He has initiated optical emission imaging of muti-magnetron pulsed plasma and contributed to the development of antibacterial implant coatings deposited by high-power impulse magnetron sputtering. He moved back to...