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Search results for: CONTROLLED MODULUS COLUMNS
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Buckling and shape control of prestressable trusses using optimum number of actuators
PublicationThis paper describes a method to control the nodal displacement of prestressable truss structures within the desired domains. At the same time, the stress in all members is unleashed to take any value between the allowable tensile stress and critical buckling stress. The shape and stresses are controlled by actuating the most active members. The technique considers the members’ initial crookedness, residual stresses, and slenderness...
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Resonant and nonresonant excitation of waves in a planar magnetosonic flow
PublicationForced propagation of perturbations in a magnetosonic wave are considered. The driving force may be caused by stimulated Mandelstam–Brillouin scattering of optic waves or by intense magnetosonic exciter. Some heating-cooling function which takes into account radiative cooling and unspecified heating is taken into consideration, as well as nonlinearity of a medium. Both these factors make the excitation particular. The analytical...
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Modelling of shear zones during quasi-static granular silo flow using material point method (MPM)
PublicationThe paper focuses on confined silo flow of cohesionless sand. The problem considered is a quasi-static flow in a plane strain model silo with parallel walls simulated with the material point method (MPM). The simulation used a non-local hypoplastic constitutive model. Initially, the paper validated the implemented numerical approach with basic element tests and a plane strain compression test. The subsequent MPM calculations for...
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Wieloobszarowa rozmyta regulacja PID mocy reaktora jądrowego
PublicationW artykule przedstawiono wieloobszarowy regulator rozmyty z lokalnymi regulatorami PID dla sterowania mocą reaktora jądrowego typu PWR. Wykorzystano model matematyczny o parametrach skupionych reaktora PWR obejmujący procesy generacji i wymiany ciepła oraz efektów reaktywnościowych. Nastawy lokalnych regulatorów PID zostały dobrane w sposób optymalny, minimalizując całkowy wskaźnik jakości ISE. Na przykładzie pokazano że zastosowane...
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The magnetic field measurements in selected places of the industrial building
Open Research DataThe dataset is part of a comprehensive study on the assessment of the electromagnetic field intensity in a building of an operating industrial plant. Detailed results of magnetic field measurements, carried out in selected places of this building, are presented.
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The conducted immunity test of a power supply unit in accordance with EMC standards
Open Research DataThe dataset presents a result of measurements that are a part of immunity tests to conducted disturbances, induced by radio-frequency fields. The immunity tests were carried out on the mains cable of the DF1723003TC NDN power supply. Tests of immunity of electronic systems to conducted disturbances in the frequency range from 150 kHz to 230 MHz are...
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublicationThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...
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Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis
PublicationIn the present paper, the identification of the material parameters of a masonry lighthouse is discussed. A fully non-invasive method was selected, in which the material properties were determined via numerical model validation applied to the first pair of natural frequencies and their related mode shapes, determined experimentally. The exact structural model was built by means of the finite element method. To obtain experimental...
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Bio-Based Polyurethane Networks Derived from Liquefied Sawdust
PublicationThe utilization of forestry waste resources in the production of polyurethane resins is a promising green alternative to the use of unsustainable resources. Liquefaction of wood-based biomass gives polyols with properties depending on the reagents used. In this article, the liquefaction of forestry wastes, including sawdust, in solvents such as glycerol and polyethylene glycol was investigated. The liquefaction process was carried...
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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete
PublicationPreplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...
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Enhanced interfacial and mechanical performance of styrene-butadiene rubber/silica composites compatibilized by soybean oil derived silanized plasticization
PublicationSilanized plasticizer (SP) was chemically derived and synthesized from soybean oil (SBO) co-vulcanized with bis-(3-(triethoxysilyl)-propyl) tetrasulfide (TESPT) by using the sulfur-accelerated curing system. SP extended styrene-butadiene rubber (SBR)/silica composites have been studied for their improved filler dispersion through coupling interaction at the SBR/silica interface. The effect of SP on cross-link density, thermal,...
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Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction
PublicationCementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone–implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to...
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Enhanced Spectroscopic Insight into Acceptor-Modified Barium Strontium Titanate Thin Films Deposited via the Sol–Gel Method
PublicationIn the present paper, composite thin films of barium strontium titanate (BaxSr1−xTiO3) with an acceptor modifier (magnesium oxide—MgO) were deposited on metal substrates (stainless steel type) using the sol–gel method. The composite thin films feature BaxSr1−xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment...
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Influence of the Addition of Recycled Aggregates and Polymer Fibers on the Properties of Pervious Concrete
PublicationThe aim of the study was to check the possibility of reusing aggregate from recycled concrete waste and rubber granules from car tires as partial substitution of natural aggregate. The main objective was to investigate the effects of recycled waste aggregate modified with polymer fibers on the compressive and flexural strength, modulus of elasticity and permeability of pervious concrete. Fibers with a multifilament structure and...
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Dual-Setting Bone Cement Based On Magnesium Phosphate Modified with Glycol Methacrylate Designed for Biomedical Applications
PublicationMagnesium phosphate cement (MPC) is a suitable alternative for the currently used calcium phosphates, owing to beneficial properties like favorable resorption rate, fast hardening, and higher compressive strength. However, due to insufficient mechanical properties and high brittleness, further improvement is still expected. In this paper, we reported the preparation of a novel type of dual-setting cement based on MPC with poly(2-hydroxyethyl...
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Organochlorine pesticides and polichlorinated biphenyls concentrations in fresh snowfall or top layer of snow from Hornsund region, Svalbard, in the spring 2019
Open Research DataThe dataset contains concentration of organochlorine persistent organic pollutants in snow samples collected from top layer of snow, which corresponded to fresh snowfall in most cases (except DS location, where these are 20 cm top layer sampled weekly). All snow samples have been collected within one month during spring 2019, in the vicinity of the...
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Estimation of zero buoyancy of the batyscaphe. Pneumatic buoyancy control of the bathyscaphe
PublicationThe subjects of this work are matters concerning the batyscaphe designed and constructed by the Scientific Circle of Young Constructors (SCoYC) acting at the Faculty of Technical Sciences of the Olsztyn University of Warmia and Mazury.The goal od the remote-controlled batyscaphe is an underwater exploration of water resorvoirs in Poland. Design and construction of the unmanned watercraft, also known as a batyscaphe, required the...
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Deterministic rendezvous of asynchronous bounded-memory agents in polygonal terrains
PublicationTwo mobile agents, modeled as points starting at differentlocations of an unknown terrain, have to meet. The terrain is a polygon with polygonal holes. We consider two versions of this rendezvous problem: exact RV, when the points representing the agents have to coincide at some time, and epsilon-RV, when these points have to get at distance less than epsilon in the terrain. In any terrain, each agent chooses its trajectory, but...
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THE APPLICATION OF KALMAN FILTERING TO PREDICT VERTICAL RAIL AXIS DISPLACEMENTS OF THE OVERHEAD CRANE BEING A COMPONENT OF SEAPORT TRANSPORT STRUCTURE
PublicationAs the devices designed to transport materials, the overhead cranes should meet certain geometric requirements for their operation to be safe. The presently available geodetic equipment, in particular total stations, provides opportunities for precise 3D measurements of coordinates of the controlled points. These coordinates make a basis for correcting the height of crane runway axes. The paper presents a method to calculate position...
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Evolving gene regulatory networks controlling foraging strategies of prey and predators in an artificial ecosystem
PublicationCo-evolution of predators and prey is an example of an evolutionary arms race, leading in nature to selective pressures in positive feedback. We introduce here an artificial life ecosystem in which such positive feedback can emerge. This ecosystem consists of a 2-dimensional liquid environment and animats controlled by evolving artificial gene regulatory networks encoded in linear genomes. The genes in the genome encode chemical...
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Selection of physiological parameters for optoelectronic system supporting behavioral therapy of autistic children
PublicationIn this article the procedure of selection of physiological parameters for optoelectronic system supporting behavioral therapy of autistic children is proposed. Authors designed and conducted an experiment in which a group of 30 health volunteers (16 females and 14 males) were examined. Under controlled conditions people were exposed to a stressful situation caused by the picture or sound (1kHz constant sound, which was gradually...
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Nano-structured Pt embedded in acidic salts of heteropolymolybdate matrices: MS EXAFS study
PublicationA structural study of Pt nano-catalysts is presented in the paper. The innovation in the case of the considered catalytic materials resides in the use a meso-microporous inorganic matrix of heteropolyacid salt of composition X2.5H0.5YMo12O40 where X = Rb, Cs and Y = P, Si as a catalyst support. Metallic nanoparticles were created by platinum ions reduction in a hot H2/Argon stream and were mainly located into matrix pores. As the...
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System supporting behavioral therapy for children with autism
PublicationIn this paper, a system supporting behavioral therapy for autistic children is presented. The system consists of sensors network, base station and a brooch indicating person's emotional states. The system can be used to measure values of physiological parameters that are associated with changes in the emotional state. In the future, it can be useful to inform the autistic child and the therapist about the emotional state of the...
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An in situ technique for the assessment of adhesive properties of a joint under load
PublicationSlow crack propagation in adhesive bonded joints has been characterised using an asymmetric wedge test. Crack position was evaluated from strain gauge measurements, both in the debonded partof the joint and in the bonded zone. Test temperature was changed during loading, giving insight into bond evolution. The technique allows accurate, and virtually continuous, determination of crack position to be made, and therefore the evaluation...
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Emotional distress, burnout and sense of safety during the COVID-19 pandemic in teachers after the reopening of schools
PublicationThe COVID-19 pandemic is having a significant impact on people's psychological well-being and mental health. This study aimed to identify factors linked to emotional distress, burnout and sense of safety in teachers related to the reopening of Polish schools after lockdown, remote work, and the holiday period between March and August 2020. A total of 1,286 teachers from different educational institutions participated in the...
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Principles and Developments of Solid-Phase Microextraction
PublicationSample preparation has been commonly considered a critical step of the analytical process. In this sense, remarkable efforts have been made to develop efficient sample preparation techniques which could overcome the limitations of conventional approaches. Since its inception in the early 1990’s, solid-phase microextraction (SPME) has become a widespread miniaturized sample preparation technique for extraction and preconcentration...
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Vegetable derived-oil facilitating carbon black migration from waste tire rubbers and its reinforcement effect
PublicationThree dimensional chemically cross-linked polymer networks present a great challenge for recycling and reutilization of waste tire rubber. In this work, the covalently cross-linked networks of ground tire rubber (GTR) were degraded heterogeneously under 150 °C due to the synergistic effects of the soybean oil and controlled oxidation. The degradation mechanism was discussed using Horikx theory and Fourier transformation infrared...
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EXPERIMENTAL RESEARCH ON INFLUENCE OF THE FUEL NOZZLE GEOMETRY ON THE FUEL CONSUMPTION OF THE MARINE 4-STROKE DIESEL ENGINE
PublicationThe article presents experimental research that has been carried out on a marine, 4-stroke, 3-cylinder, turbocharged engine. During testing, the engine operated at a constant rotational speed of 750 rpm and a load from 0 kW to 280 kW. The engine was fuelled by diesel oil of known specification and loaded by electric generator with water resistance. The fuel consumption was measured during the engine operation with fuel nozzles...
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Damage detection in a bolted lap joint using guided waves
PublicationThe paper presents the experimental investigation of guided waves application to the condition assessment of prestressed bolted connections and a concept of new quantitative indicator. The main goal of the research was the analysis of the influence of the contact conditions changes to the characteristics of a propagating disturbance. The experimental tests were carried out for a single bolted lap joint. The excitation and acquisition...
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Limited selectivity of amperometric gas sensors operating in multicomponent gas mixtures and methods of selectivity improvement
PublicationIn recent years, smog and poor air quality have became a growing environmental problem. There is a need to continuously monitor the quality of the air. The lack of selectivity is one of the most important problems limiting the use of gas sensors for this purpose. In this study, the selectivity of six amperometric gas sensors is investigated. First, the sensors were calibrated in order to find a correlation between the concentration...
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Systematic Water Uptake Energetics of Yttrium-Doped Barium Zirconate—A High Resolution Thermochemical Study
PublicationA combination of surface area analyzer and microcalorimetry was employed to investigate the in situ water uptake energetics and the mechanism of proton incorporation in yttrium-doped barium zirconate in the temperature range 200–400 °C. The BaZr1–xYxO3 solid solutions are made with variable yttrium content (x = 10, 20, and 30 mol %) by a controlled oxidant-peroxo synthesis method. The water uptake increases as the partial pressure...
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Surface Texture Analysis of Hardened Shafts after Ceramic Ball Burnishing
PublicationThis article represents the results of testing the surface condition of shafts manufactured by the burnishing process. The shafts with a hardness of approximately 62 HRC (Rockwell C). were burnished with a ceramic ball (Si3N4), where the force range was controlled by the means of a hydraulic system. The machining process consisted of hard turning shafts with cubic boron nitride (CBN) inserts, followed by burnishing with the use...
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Modelling and Analysis of the Positioning Accuracy in the Loading Systems of Mobile Cranes
PublicationIn this work, the authors analyse the influence of the order and range of sequential movements of a crane's working members on the accuracy of the final cargo positioning. The analysis was conducted on the basis of a specially developed method in which the authors proposed the introduction of a geometrical indicator of positioning the load in the intermediate positions (after completing each movement sequence) and in the target...
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The valance state of vanadium-key factor in the flexibility of potassium vanadates structure as cathode materials in Li-ion batteries
PublicationPotassium hexavanadate (K2V6O16·nH2O) nanobelts have been synthesized by the LPE-IonEx method, which is dedicated to synthesis of transition metal oxide bronzes with controlled morphology and structure. The electrochemical performance of K2V6O16·nH2O as a cathode material for lithium-ion batteries has been evaluated. The KVO nanobelts demonstrated a high discharge capacity of 260 mAh g−1, and long-term cyclic stability up to 100...
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Fatigue fracture surface metrology of thin-walled tubular austenitic steel specimens after asynchronous loadings
PublicationThis paper aims to study the effect of asynchronous axial-torsional strain-controlled loading histories on fracture surface behavior of thin-walled tubular X5CrNi18-10 (304/304L) austenitic steel specimens. Tests under pure axial loading and pure torsional loading are also conducted to better segregate the effect of multiaxiality. The fractures surface topographies were examined through the profiles over the entire surface with...
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The influence of IT-competency dimensions on job satisfaction, knowledge sharing and performance across industries
PublicationPurpose – Technology makes knowledge management easier. Knowledge sharing is essential for organizational development. Job satisfaction fosters knowledge sharing. Hence, this study aims to develop an understanding of the mutual relationship between knowledge sharing and job satisfaction when both are predicted by information technology (IT)-competency dimensions such as IT-operations, IT-knowledge and IT-infrastructure in the context...
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Transport of paracetamol in swellable and relaxing polyurethane nanocomposite hydrogels
PublicationPolyurethane hydrogels are potentially attractive materials for biomedical applications. They are able to absorb large amount of water, biological fluids or active substances, and thus, they have potential to be used as absorbents or wound-healing dressings. They are also used for the controlled release of therapeutics because of their capacity to embed biologically active agents in their water-swollen network. The presence of...
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Evaluation of the Commercial Electrochemical Gas Sensors for the Monitoring of CO in Ambient Air
PublicationAir pollution is a growing concern of civilized world, which has a significant impact on human health and the environment. Recent studies highlight that the exposure to polluted air can increase the incidence of diseases and deteriorate the quality of life. Hence, it is necessary to develop tools for real-time air quality monitoring. For air pollution monitoring a wide range of stationary gas and particulate analysers can be used....
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Biopolymers and Their Composites for Drug Delivery: A Brief Review
PublicationIn recent years, excipient development has become a core area of research in pharmaceutical drug delivery because it influences the formulation development and drug delivery process in various ways. Polymeric drug delivery systems have been of great interest for controlled delivery as they show the great advantage in drug delivery systems because of optimized drug loading and releasing property. Then, the side effects of synthetic...
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Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components
PublicationThis paper aims to compare the predictive capabilities of different one-parameter damage laws and local stress-strain approaches to assess the fatigue lifetime in notched components subjected to proportional bending-torsion loading. The tested fatigue damage parameters are defined using well-known stress-based, strain-based, SWT-based and energy-based relationships. Multiaxial cyclic plasticity at the notch-controlled process zone...
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The influence of the size of a one-faced metallic head in Janus nanoparticles as a co-catalyst on the photocatalytic efficiency of hydrogen evolution under vis light irradiation
PublicationJanus nanoparticles (NPs) consisting of MoOxSy nanospheres and silver (Ag) head, successfully developed by a simple, controlled method were in the first time they were applied as a co-catalysts in photocatalytic hydrogen generation reaction under vis light irradiation (λ > 420 nm). The MoOxSy-Ag as a co-catalysts were deposited on the obtained ZnIn2S4 microspheres (ZIS) using physical absorption method. The influence of the size...
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Development of a Friction Welding System for CNC Lathes
PublicationDedicated friction welding machines are sturdy in order to handle large process forces but expensive. Thus, it is proposed to equip two axis CNC lathes with an add-on direct drive friction welding system as an affordable solution for occasional use. The first part to be welded is clamped on the lathe chuck, whilst the second part is clamped on a dedicated chuck on the tailstock. The latter is programmed to follow three phases:...
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Effect of kenaf fibre modification on morphology and mechanical properties of thermoplastic polyurethane materials
PublicationThe presented study examined the morphology and mechanical properties of biocomposites obtained from kenaf natural fibre and thermoplastic polyurethane. Kenaf was modified using various methods, namely: acetylation, blocked isocyanate, maleic anhydride and permanganate treatment. Those methods and ways of carrying out of surface modifications were not studied before on kenaf/thermoplastic polyurethane composites. Different fibre...
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Transparent nanocomposite coatings based on epoxy and layered double hydroxide: Nonisothermal cure kinetics and viscoelastic behavior assessments
PublicationLayered double hydroxide (LDH) has a particular place in clay family because of its flame retardant action. The nanoplatelet-like structure of LDH makes possible development of polymer composites with cationic or anionic nature structures in which macromolecules are positioned in between nanoplatelet galleries. In this work, neat epoxy and its transparent nanocomposite coatings with sodium dodecylbenzene sulfonate (SDBS)-modified...
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Generalization of Kramers-Krönig relations for evaluation of causality in power-law media
PublicationClassical Kramers-Krönig (K–K) relations connect real and imaginary parts of the frequency-domain response of a system. The K–K relations also hold between the logarithm of modulus and the argument of the response, e.g. between the attenuation and the phase shift of a solution to a wave-propagation problem. For square-integrable functions of frequency, the satisfaction of classical K–K relations implies causality in the time domain....
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THE ANALYSIS OF THE INFLUENCE OF STRESS DISTRIBUTION ON WEAR PROFILE IN LUBRICATED SLIDING CONTACT OF UHMW-PE VS TITANIUM Ti-13Nb-13Zr ALLOY
PublicationMetal – polymer sliding contacts are a typical combination in industry and medicine. For decades such a set of materials has been the primary choice in human joints endoprosthetic technology. In this paper tribological issues of are presented from a research on the potential for practical use of Ti-13Nb-13Zr/UHMW-PE couple for orthopedic endoprosthesis. In tests on simplified models it is critically important to carefully...
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Experimental and Numerical Investigation of Mechanical Properties of Lightweight Concretes (LWCs) with Various Aggregates
PublicationHigh requirements for the properties of construction materials and activities directed at environment protection are reasons to look for new solutions in concrete technology. This research was directed at solutions affecting the reduction of energy consumption and CO2 emissions. The use of lightweight concretes (LWCs) allows one to meet both conditions at the same time. The purpose of the research presented in this paper was to...
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Electrophoretic Deposition and Characterization of Chitosan/Eudragit E 100 Coatings on Titanium Substrate
PublicationCurrently, a significant problem is the production of coatings for titanium implants, which will be characterized by mechanical properties comparable to those of a human bone, high corrosion resistance, and low degradation rate in the body fluids. This paper aims to describe the properties of novel chitosan/Eudragit E 100 (chit/EE100) coatings deposited on titanium grade 2 substrate by the electrophoretic technique (EPD). The deposition...
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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublicationThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Synthesis and characterization of biopolyols through biomass liquefaction of wood shavings and their application in the preparation of polyurethane wood composites
PublicationThe sustainability of production systems in wood processing, wood industry, and wooden waste disposal is an important issue for European industry and society. Proper development of products based on renewable wood resources gives an opportunity to provide materials with long-term environmental, social, and economic sustainability. This study aims to establish a new way of forestry and agricultural waste materials utilization by...