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Search results for: PTFE COATING
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Modelling the Kerf Angle, Roughness and Waviness of the Surface of Inconel 718 in an Abrasive Water Jet Cutting Process
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Experimental investigation on the effect of dry and multi-jet cryogenic cooling on the machinability and hole accuracy of CFRP composites
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Evaluation of Surface Topography after Face Turning of CoCr Alloys Fabricated by Casting and Selective Laser Melting
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Automatic Adjustment of Integration Time in the NIR Camera for Calibrated Temperature Measurement during Inductive Heating Processes
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Application of the theory of energy transformation systems to fatigue assessment of steel elements under multiaxial periodic loading
PublicationPraca dotyczy symulacji odporności zmęczeniowej elementów stalowych poddanych wieloosiowym obciążeniom okresowym w zakresie wysokocyklowym. W tym celu zdefiniowano jednoosiowe naprężenie sinusoidalne, równoważne w sensie trwałości zmęczeniowej materiału naprężeniu aktualnemu gdy każda jego kartezjańska składowa jest dana w postaci szeregu Fouriera. Warunki równoważności wynikają z teorii systemów transformacji energii i wiążą się...
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Development of linear projecting in studies of non-linear flow. Acoustic heating induced by non-periodic sound
PublicationRównanie bilansu energii rozkłada się na sumę dwóch równań, opisujących dynamikę fali akustycznej i wywołanego przez nią ogrzewania. Nowe równanie dynamiczne stosowane jest dla opisu dźwięku nieokresowego zarówno jak okresowego. Rozpatruje się geometrię wiązkową. Omówiane są poszczególne udziały przewodnictwa cieplnego i lepkości w ogrzewaniu akustycznym. Równania stanu ośrodka propagacji są uwzględniane w najbardziej ogólnej postaci.
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Enhancement of lift and drag performances of a NACA0012 airfoil by multi-DBD plasma actuator with additional floating interelectrodes
PublicationIt is clear that the improvement of aircraft aerodynamic performances is currently and will continue to be a significant area of research for the aeronautical industry. The current study is focused on theenhancement of aerodynamic airfoil performances by using a multi-DBD plasma actuator mounted around the model leading-edge. Experiments have been conducted at the University of Orleans, in the 2 m x 2 m test section of a large...
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The Effect of Wood Provenance and Density on Cutting Forces While Sawing Scots Pine (Pinus sylvestris L.)
PublicationSeveral properties of wood including the cutting power requirements can be correlated to wood density. Therefore, according to the literature, the cutting power requirements (and/or cutting forces) could be computed as a function of the wood specific gravity. This research shows that such an approach, based solely on specific gravity, may be considered a rather rough and imperfect estimate of cutting power. Samples of Scots pine...
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Comparison of heat transfer characteristics in surface cooling using microjets with water, ethanol and HFE7100 as test fluids
PublicationAccurate control of cooling parameters is required in ever wider range of technical applications. It is known that reducing the dimensions of the size of nozzle leads to an increase in the economy of cooling and improves its quality. Present study describes research related to the design and construction of the nozzles and microjet study, which may be applied in many technical applications such as in metallurgy, electronics, etc....
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Revisiting The Determination Of Cutting Power While Sawing Of Wood With Circular Saw Blades By Means Of Fracture Mechanics
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, cutting forces (power) could be considered from a point of view of modern fracture mechanics. Cutting forces may be employed to determine not only toughness...
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The differential impact of a density of Polish pine wood on cutting forces with its origin region taken into consideration
PublicationIn the article the dependence of cutting forces in a function the density of wood with regard to the wood origin are presented. Samples used in experiment were with Scotch pine (Pinus sylvestris L.) originating from four provenances in Poland (Figure 1). Wood density was measured by two methods: stereometric method (global density) and radiometric method (local density). Stereometric method consists in measurements the volume...
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Method of selective fading as a educational tool to study the behaviour of prestressed concrete elements under excess loading
PublicationPrestressed structures are a key to realization of the boldest architectural ideas, characteristic feature of prestressed structure is better use of concrete material properties by insertion of internal forces. Learning about pre-stressed reinforced concrete structures is an integral part of Graduate Studies Program in construction engineering. Know-how of geometry change patterns in prestressed concrete elements under certain...
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Multicriteria Optimization Approach to Design and Operation of District Heating Supply System over its Life Cycle
PublicationDistrict Heating (DH) systems are commonly supplied using local heat sources. Nowadays, modern insulation materials allow for effective and economically viable heat transportation over long distances (over 20 km). In the paper a method for optimized selection of design and operating parameters of long distance Heat Transportation System (HTS) is proposed. The method allows for evaluation of feasibility and effectivity of heat transportation...
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Minimizing Distribution and Data Loading Overheads in Parallel Training of DNN Acoustic Models with Frequent Parameter Averaging
PublicationIn the paper we investigate the performance of parallel deep neural network training with parameter averaging for acoustic modeling in Kaldi, a popular automatic speech recognition toolkit. We describe experiments based on training a recurrent neural network with 4 layers of 800 LSTM hidden states on a 100-hour corpora of annotated Polish speech data. We propose a MPI-based modification of the training program which minimizes the...
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Effect of high loading of titanium dioxide particles on the morphology and selected properties of natural rubber-based composites
PublicationThe aim of this work was to prepare and characterize the natural rubber vulcanizates contained different amounts of titanium dioxide particles. At first rubber mixture was prepared using a laboratory two-roll mill and then samples were vulcanized in a hydraulic press. The formulation of rubber mixture and rubber-processing technique is based on our earlier investigations. Materials were obtained at the different titanium dioxide...
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CREATING A RANKING OF DIAGNOSTIC PARAMETERS FOR THE DYNAMIC PROCESS OF A MARINE COMBUSTION ENGINE IN THE ASPECT OF MULTI-CRITERIA EVALUATIONS
PublicationThe change of some of the engine’s structural parameters affects the change of toxic compound emission in exhaust gases. It mainly applies to the damage sustained by the charge exchange system as well as the fuel system and the engine supercharging system. These changes are definitely higher during dynamic states and the related transient states. As such, it is possible to speak of a diverse sensitivity of the diagnostic parameters...
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Cutting model parameters from frame sawing of natural and impregnated Scots pine (Pinus sylvestris L.)
PublicationIn this paper, absolute and density normalized cutting model parameters of natural and impregnated Scots pine (Pinus sylvestris L.) are shown and a method for the calculation of their corresponding material properties in the principal material directions of wood is presented. The parameters were determined from measurements of cutting power on a sash gang saw, and are in detail the fracture toughness and the shear yield strength...
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Analysis of the Surface Stereometry of Alloyed Austenitic Steel after Fibre Laser Cutting using Confocal Microscopy
PublicationThe paper extends the concept of cut edge quality and examines the fibre laser cutting process. A Prima Power Platino Fiber Evo device with a reference speed (RS) of 3500 mm/min was used for laser cutting. In order to analyse the influence of the laser cutting speed on the cut edge quality of X5CrNi18-10 stainless steel sheets, macroscopic studies were conducted on a stereoscopic microscope and surface stereometry on a confocal...
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Contr-rotating eccentric-mass rotors used as exciters of sinusoidal forces applied to elastically supported bodies
PublicationThe work focuses on aspects of multibody dynamics. Investigated object is a mass driven by rotations of an inertial shaker. Resulting vibrational set consists of two counter-rotating identically-unbalanced rotors. Since the mass centres of the rotors do not coincide with the axes of their rotations, significant centrifugal forces arise during rotations. As both rotors are identically unbalanced, the inter-axial force components...
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Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
PublicationIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Corrosion Resistance and Surface Bioactivity of Ti6Al4V Alloy after Finish Turning under Ecological Cutting Conditions
PublicationThe influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected...
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Frequency-Reconfigurable Hybrid SIW-Based Self-Diplexing Antenna Using Solid and Liquid Dielectric Loading
PublicationThis paper presents a novel frequencyreconfigurable self-diplexing antenna (SDA) utilizing a hybrid substrate-integrated waveguide (SIW). The antenna comprises a radiating slot, a feeding network, and a hybrid SIW cavity featuring half-mode circular and half-mode rectangular SIW structures. The unique feature of this antenna lies in its fine-tuning capability of each resonant frequency by inserting or injecting solid and liquid...
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How do responsible universities perceive their social engagement? In search of signs of Creating Shared Value by the University
PublicationObjectives: University social responsibility still lacks legitimisation and is perceived as a burden that hinders academics from doing research and teaching. Creating Shared Value by the University may serve as a tool to motivate universities to engage in initiatives for society, as this is beneficial for both parties. Yet, some researchers perceive the creation of economic value as inappropriate for academia. Thus, it was interesting...
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A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublicationIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
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Numerical Determination of the Load-Bearing Capacity of a Perforated Thin-Walled Beam in a Structural System with a Steel Grating
PublicationThis article presents the results of numerical simulations of a structural system consisting of steel perforated thin-walled beams and a steel grating. The simulations were conducted using the finite element method. The analysis took into account physical and geometric nonlinearity as well as the contact between the steel grating and the beams. The main goal of the research was to develop load-bearing curves for the main beam in...
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ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART III DIMENSIONAL ANALYSIS
PublicationThis article presents the third and last part of the problem of diagnosing the fatigue of marine propulsion shafts in terms of energy with the use of the action function, undertaken by the authors. Even the most perfect physical models of real objects, observed under laboratory conditions and developed based on the results of their research, cannot be useful in diagnostics without properly transferring the obtained results to the...
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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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Application of enhanced elasto-plastic damage models to concrete under quasi-static and dynamic cyclic loading
PublicationArtykuł omawia wyniki symulacji zachowania sie elementów betonowych poddanych zginaniu w czasie cyklicznego obciążenia. Do symulacji zastosowano 3 połączone modele sprężysto-plastyczne z degradacją sztywności i z nielokalnym osłabieniem. Wyniki symulacji porównano bezpośrednio z doświadczeniami.
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Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C
PublicationThis paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly...
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Highly Oriented Zirconium Nitride and Oxynitride Coatings Deposited via High‐Power Impulse Magnetron Sputtering: Crystal‐Facet‐Driven Corrosion Behavior in Domestic Wastewater
PublicationHerein, highly crystalline ZrxNy and ZrxNyOz coatings are achieved by the deposition via high‐power impulse magnetron sputtering. Various N2 and N2/O2 gas mixtures with argon are investigated. The chemical composition and, as a result, mechanical properties of the deposited layer can be tailored along with morphological and crystallographic structural changes. The corrosion resistance behavior is studied by potentiodynamic measurements...
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Application of Headspace Solid-phase Microextraction with Poly(1-vinyl-3- Hexylimidazolium Chloride) Polymeric Ionic Liquid Coating using GC - MS to Determine Volatile Fatty Acids in Dairy Wastewater
PublicationVolatile fatty acids were determined in this study using headspace solid-phase microextraction (HS-SPME) with a poly(1-vinyl-3-hexylimidazolium chloride) polymeric ionic liquid coated fiber followed by gas chromatography - mass spectrometry. Experimental parameters such as extraction time and temperature, sample volume as well as desorption time and temperature were optimized. Detection limits of the method were in the range of...
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The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition
PublicationThe superionic α ↔ β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and measurements of Seebeck coefficient and electrical conductivity. Results of the DSC measurements with 1–10 K/min heating and cooling rates show that the material is close to the equilibrium phase composition during the transformation. However, the kinetic limitation of the process exists, which is indicated...
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Warstwy funkcjonalne tlenkowych ogniw paliwowych
PublicationIn this paper, results describing current research on solid oxide fuel cells conducted at Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics are presented. The results are related to three kinds of functional layers: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow...
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The influence of plastic working on the selection properties of the nickel - aluminium alloy coatings = Wpływ obróbki plastycznej na wybrane właściwości powłok stopowych nikiel - aluminium
PublicationW pracy przedstawiono wyniki badań nad możliwością zastosowania technologii obróbki plastycznej (walcowania na zimno i gorąco, oraz prasowania) do kształtowania wybranych właściwości natryskiwanych płomieniowo powłok stopowych Ni-5%Al o strukturze jednofazowej, a mianowicie granicznego roztworu stałego , o maksymalnej 10% rozpuszczalności glinu w sieci krystalograficznej niklu. Celem pracy jest wstępna analiza możliwości zastąpienia...
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Some coatings of high cavitation resistance produced by CO2 laser beam. XIV International Symposium on Gas Flow, Chemical Lasers and High Power Lasers.
PublicationPrzedstawiono wyniki badań odporności kawitacyjnej stali 2H13, 45 i żelaza Armco po laserowym stopowaniu ich powierzchni różnymi kompozycjami proszków Co, Mo, Ni, Mn i Cr, Ti. Wykazano różne własności kawitacyjne otrzymanych warstw w zależności od otrzymanej mikrostruktury.
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Badania uszkodzeń powłok ceramicznych wskutek tarcia ślizgowego w ruchu postępowo-zwrotnym = Wear pattern testing of ceramic coatings under reciprocating sliding
PublicationBadano (wykorzystując mikroskop optyczny oraz skaningowy) morfologię uszkodzeń wybranych powłok ceramicznych ( m.in. DLC z dodatkiem wolframu) nakładanych na podłoże stalowe, będących skutkiem tarcia slizgowego w ruchu postępowo-zwrotnym skojarzenia kula-powierzchnia płaska. Ślady zużycia na kulach, czyli obszary wygładzonych plateau, mają kształt zbliżony do elipsy. Praca, przy zmiennym zwrocie sił stycznych działających na powierzchnię...
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WEAR TESTING OF DLC COATINGS WITH FRICTION COUPLE „BALL-ON-DISK” = Badania zużycia powłok DLC w skojarzeniu kula-tarcza obrotowa ''ball-on-disk''
PublicationW Katedrze Konstrukcji i Eksploatacji Maszyn PG opracowano metodę badania powłok DLC oraz innych (ceramicznych) w układzie kula - płaska powierzchnia obrotowej tarczy ("ball-on-disk"). Układ badawczy składa się z kuli osadzonej w popychaczu łożyskowanym tocznie, poprzez który wywierana jest siła docisku próbek. Kula dociskana jest od góry do płaskiej powierzchni obrotowej tarczy - próbki dolnej (o pionowej osi obrotu). Próbka dolna...
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Propagation of initially sawtooth periodic and impulsive signals in a quasi-isentropic magnetic gas
PublicationThe characteristics of propagation of sawtooth periodic and impulsive signals at a transducer are analytically studied in this work. A plasma under consideration is motionless and uniform at equilibrium, and its perturbations are described by a system of ideal magnetohydrodynamic equations. Some generic heating/cooling function, which in turn depends on equilibrium thermodynamic parameters, may destroy adiabaticity of a flow and...
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Antibacterial properties of laser-encapsulated titanium oxide nanotubes decorated with nanosilver and covered with chitosan/Eudragit polymers
PublicationTo provide antibacterial properties, the titanium samples were subjected to electrochemical oxidation in the fluoride-containing diethylene glycol-based electrolyte to create a titanium oxide nanotubular surface. Afterward, the surface was covered by sputtering with silver 5 nm film, and the tops of the nanotubes were capped using laser treatment, resulting in an appearance of silver nanoparticles (AgNPs) of around 30 nm in diameter...
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Titania Nanotubes/Hydroxyapatite Nanocomposites Produced with the Use of the Atomic Layer Deposition Technique: Estimation of Bioactivity and Nanomechanical Properties
PublicationTitanium dioxide nanotubes/hydroxyapatite nanocomposites were produced on a titanium alloy (Ti6Al4V/TNT/HA) and studied as a biocompatible coating for an implant surface modification. As a novel approach for this type of nanocomposite fabrication, the atomic layer deposition (ALD) method with an extremely low number of cycles was used to enrich titania nanotubes (TNT) with a very thin hydroxyapatite coating. X-ray diffraction (XRD)...
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Influence of Gd deposition on the oxidation behavior and electrical properties of a layered system consisting of Crofer 22 APU and MnCo2O4 spinel
PublicationIn the study, the surface of the Crofer 22APU ferritic steel was modified with gadolinium oxide nanoparticles and a protective-conducting layer consisting of the MnCo2O4 spinel. This system was studied in the context of application in IT-SOFC interconnects. Four types of samples were studied: unmodified steel, steel coated with a manganese-cobalt spinel layer, steel modified with gadolinium oxide nanoparticles, and a system consisting...
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Evaluating the challenges and needs of parents caring for children with Williams syndrome: A preliminary study from Poland
PublicationBackground: Although physical, cognitive and behavioural manifestations of Williams syndrome(WS) affect every dimension of caregivers lives, no studies on the parental experiences of caringfor a WS child have to date been carried out in Poland.Methods: In order to identify the challenges and needs of Polish carers of WS children a survey wasconducted...
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On the Trail of the Oldest Domestic Cat in Poland. An Insight from Morphometry, Ancient DNA and Radiocarbon Dating
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Characterisation and OSL dating of modern fluvial sediments in the lower Vistula River: testing the zeroing assumption
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Professional activity, gender and disease-related emotions: The impact on parents' experiences in caring for children with phenylketonuria
PublicationIntroduction: Clinical management of rare diseases often fails to acknowledge the challenges faced by caregivers.Whilst management of phenylketonuria (PKU) may not be considered as dire as other conditions, most studiesprimarily concentrate on clinical issues, dietary adherence, or the quality of life of the PKU patients, leavingcaregivers in the background. The aim of the study was to evaluate the psychosocial...
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Coping of Chronically-Ill Patients during the COVID-19 Pandemic: Comparison between Four Groups
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Professional activity, gender and disease-related emotions: The impact on parents' experiences in caring for children with phenylketonuria
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Safeguarding democracy during pandemics. Social distancing, postal, or internet voting—the good, the bad, or the ugly?
PublicationDuring a pandemic, many countries and organizations must decide whether to postpone upcoming elections or to hold them (Krimmer et al., 2020a). If the decision is made to hold the election, three main scenarios come to mind: continue using the existing system but include measures to ensure the health of participants; or look for alternatives among remote voting channels which could ensure social distancing is guaranteed either...
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Electrophoretically deposited titanium and its alloys in biomedical engineering: Recent progress and remaining challenges
PublicationOver the past decade, titanium implants have gained popularity as the number of performed implantation operations has significantly increased. There are a number of methods for modifying the surface of biomaterials, which are aimed at extending the life of titanium implants. The developments in this field in recent years have required a comprehensive discussion of all the properties of electrophoretically deposited coatings on...
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Laboratory research on the influence of swelling clay on the quality of borehole cementing and evaluation of clay-cutting wellbore tool prototype
PublicationSwelling clay phenomenon is frequently observed during oil and gas drilling operations and has a significant impact on the quality of cementing procedure. Certain types of clayey minerals increase their volume in contact with water-based drilling fluids. After drilling is completed, borehole remains unsupported and filled with waterbased drilling fluids for several hours, before a casing string is inserted and secured with cement....