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The vibration-based assessment of the influence of elevated temperature on the condition of concrete beams with pultruded GFRP reinforcement
PublikacjaConcrete beams reinforced with glass fiber reinforced polymer (GFRP) bars subjected to elevated temperature have been experimentally studied. The influence of high temperatures on GFRP-reinforced concrete beams condition has been check both, destructively and nondestructively. The nondestructive tests foresaw vibration-based tests to obtain the natural frequency values after exposure to varying temperatures. The vibration-based...
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Structural Changes and Their Implications in Foamed Flexible Polyurethane Composites Filled with Rapeseed Oil-Treated Ground Tire Rubber
PublikacjaThe utilization of post-consumer car tires is an essential issue from an ecological andeconomic point of view. One of the simplest and the least harmful methods is their material recyclingresulting in ground tire rubber (GTR), which can be further applied as fillers for polymer-basedcomposites. Nevertheless, insufficient interfacial interactions implicate the necessity of GTR modi-fication before introduction into polymer matrices....
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Soiling Effect Mitigation Obtained by Applying Transparent Thin-Films on Solar Panels: Comparison of Different Types of Coatings
PublikacjaDust accumulation on the front cover of solar panels is closely linked to location and orientation of photovoltaic (PV) installation. Its build-up depends on the module tilt angle, frequency of precipitation, humidity, wind strength and velocity, as well as grain size. Additionally, soil composition is determined by solar farm surroundings such as local factories, agricultural crops, and traffic. Over time, molecules of atmospheric...
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Multiple Reprocessing of Conductive PLA 3D-Printing Filament: Rheology, Morphology, Thermal and Electrochemical Properties Assessment
PublikacjaAdditive manufacturing technologies are gaining more and more attention, resulting in the development or modification of 3D printing techniques and dedicated materials. On the other hand, economic and ecological aspects force the industry to develop material recycling strategies. In this work, the multiple reprocessing of a commercially available PLA conductive composite with carbon black filler, dedicated to 3D printing, was investigated....
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Stress Relaxation Behaviour Modeling in Rigid Polyurethane (PU) Elastomeric Materials
PublikacjaPolyurethane (PU) has been used in a variety of industries during the past few years due to its exceptional qualities, including strong mechanical strength, good abrasion resistance, toughness, low-temperature flexibility, etc. More specifically, PU is easily “tailored” to satisfy particular requirements. There is a lot of potential for its use in broader applications due to this structure–property link. Ordinary polyurethane items...
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Material characterisation of biaxial glass-fibre non-crimp fabrics as a function of ply orientation, stitch pattern, stitch length and stitch tension
PublikacjaDue to their high density-specific stiffnesses and strength, fibre reinforced plastic (FRP) composites are particularly interesting for mobility and transport applications. Warp-knitted non-crimp fabrics (NCF) are one possible way to produce such FRP composites. They are advantageous because of their low production costs and the ability to tailor the properties of the textile to the reinforcement and drape requirements of the application....
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Diagnostics and monitoring of the longest span extradosed bridge in Europe
PublikacjaThe article presents complex diagnostic procedures applied for the purpose of behavior analysis of the extradosed bridge with the longest span in Europe that was built in 2018 in Poland. The system of health monitoring was used to: register internal forces in temporary supports, monitor concrete bonding, perform in situ diagnostics and operation tests. The bridge is a continuous four-span structure with spans theoretical lengths...
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Studies on the Combined Impact of Starch Source and Multiple Processing on Selected Properties of Thermoplastic Starch/Ethylene-Vinyl Acetate Blends
PublikacjaThermoplastic starch (TPS)/ethylene vinyl acetate (EVA) blends compatibilized with polyethylene-graft-maleic anhydride (PE-g-MA) were prepared from various native starches (potato, maize and waxy maize) and subjected to multiple extrusion cycles. Source of starch has significant impact on its composition, hence properties of obtained TPS and their blends with EVA. Higher content of amylopectin in waxy maize starch, comparing to...
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Further development of the poroelastic road surface within the new Polish project SEPOR
PublikacjaRoad surfaces have a direct impact on noise generated by rolling tyres, the main and dominant source of noise of moving vehicles. Road surface texture, porosity and stiffness/elasticity govern the pavement contribution to tyre/road noise the most. An experimental PoroElastic Road Surface (PERS) is a wearing course with a high content of interconnected voids (pores) and with an elastic behavior due to the use of small particles...
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Application of cyanated asphaltenes in gas-phase adsorption processes for removal of volatile organic compounds
PublikacjaThe paper presents an innovative, chemically modified (methylcyanated) asphaltene-based adsorbent that can be an inter-esting low-cost alternative for traditional adsorbents. Adsorption properties of adsorbents were examined by inverse gas chromatography technique, adsorption isotherms, and breakthrough curves. A significant increase in retention volume for pyridine, 2-pentanone, nitropropane, toluene, and 1-butanol was observed....
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Preparation and Characterization of Films Based on Disintegrated Bacterial Cellulose and Montmorillonite
PublikacjaThe food packaging materials from natural polymers including polysaccharides offer an ecologically important alternative to commonly used synthetic, non-biodegradable counterparts. The purpose of this work was to modify of bacterial cellulose (BC) leading to the improvement of its functional properties in terms of use as a food packaging material. Effects of disintegration of BC and addition of montmorillonite (MMT) on its water...
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Submicron inorganic particles as an additional filler in hybrid epoxy matrix composites reinforced with glass fibres
PublikacjaIn this study, the effect of selected submicron metal oxide (zinc oxide, titanium oxide) or non-metal oxide (silicon dioxide) particles on mechanical and thermo-mechanical properties of epoxy/glass composites was investigated. The applied epoxy resin was a diglycidyl ether of bisphenol-A cured with triethylenetetramine. As a reinforcement twill weave E-glass fabric was used. Hybrid composites (contained particulate and fibrous...
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Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti13Nb13Zr Alloy
PublikacjaTitanium implants are commonly used because of several advantages, but their surface modification is necessary to enhance bioactivity. Recently, their surface coatings were developed to induce local antibacterial properties. The aim of this research was to investigate and compare me-chanical properties of three coatings: multi-wall carbon nanotubes (MWCNTs), bi-layer composed of an inner MWCNTs layer and an outer TiO2 layer, and...
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Thermal properties of a cement composite containing phase change materials (PCMs) with post-pyrolytic char obtained from spent tyres as a carrier
PublikacjaThis work examines the possible use of post-pyrolysis char made from spent vehicle tyres as a carrier for phase change materials (PCM), which could be used as an additive to cement mortar. Because of the ability of PCM to accumulate heat, the cement composite obtained from it, apart from its structural and strength properties, will acquire an additional energy storage function, which can be very important for energy-saving construction. In...
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Anion–water interactions of weakly hydrated anions: molecular dynamics simulations of aqueous NaBF4 and NaPF6
PublikacjaIn aqueous ionic solutions, both the structure and the dynamics of water are altered dramatically with respect to the pure solvent. The emergence of novel experimental techniques makes these changes accessible to detailed investigations. At the same time, computational studies deliver unique possibilities for the interpretation of the experimental data at the molecular level. Here, using molecular dynamics simulations, we demonstrate...
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Interfacial adhesion evaluation in (low-density polyethylene)/elastomer blends
PublikacjaLow-density polyethylene (LDPE) with different elastomers at a ratio of 50/50 wt% blends was prepared by using a co-rotating twin-screw extruder. Three kinds of elastomers were used: ground tire rubber (GTR), partially crosslinked butyl rubber (KalarVR ), and styrenebutadiene- rubber block copolymer (SBS; KratonVR ). For better characterization of interaction between polyethylene and elastomer, influence of the type of elastomer on...
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Curing characteristics, mechanical and thermal properties of reclaimed ground tire rubber cured with various vulcanizing systems
PublikacjaGround tire rubber was thermo-mechanical reclaimed at 120 °C using a co-rotating twin screw extruder. The effect of vulcanizing system type on curing characteristics, static mechanical properties (tensile strength, elongation-at-break, hardness and resilience), dynamic mechanical properties and thermal properties of reclaimed ground tire rubber was investigated. Reclaimed rubber was cured using different types of vulcanization...
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Modern GFRP Composite Footbridges
PublikacjaApplication of GFRP composites in civil engineering is still not large but already noticeable. Advantages of this material, such as: low volume weight, relatively high stiffness and strength, well fatigue resistance, easiness in shaping, high material damping and high environmental resistance, make it attractive for bridge and in particular foot-bridge designers. It is estimated that nowadays in the world there are realized hundreds...
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Application of Shape Memory Alloys in Retrofitting of Masonry and Heritage Structures Based on Their Vulnerability Revealed in the Bam 2003 Earthquake
PublikacjaFor decades, one of the most critical considerations of civil engineers has been the construction of structures that can sufficiently resist earthquakes. However, in many parts of the globe, ancient and contemporary buildings were constructed without regard for engineering; thus, there is a rising necessity to adapt existing structures to avoid accidents and preserve historical artefacts. There are various techniques for retrofitting...
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A distributed system for conducting chess games in parallel
PublikacjaThis paper proposes a distributed and scalable cloud based system designed to play chess games in parallel. Games can be played between chess engines alone or between clusters created by combined chess engines. The system has a built-in mechanism that compares engines, based on Elo ranking which finally presents the strength of each tested approach. If an approach needs more computational power, the design of the system allows...
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Skłonność do rywalizacji a intencje przedsiębiorcze – o różnicach międzypłciowych
PublikacjaAccording to the person-environment fit model people are more inclined to choose particular careers paths over other depending on their individual characteristics. They are also more likely to be satisfied with a career path that matches their characteristics and less likely to experience negative consequences including strain. In previous research several characteristics of entrepreneurs which differentiate them from non-entrepreneurs...
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Load-carrying capacity of axially loaded concrete-filled steel tubular columns made of thin tubes
PublikacjaAn experimental investigation was conducted on 30 CFST columns. An influence of the following factors on load-carrying capacity of the investigated columns was analyzed: the column slenderness (l1 = 42, l2 = 27 and l3 = 15), the tube thickness (the reinforcement ratio was equal to 4% or 6%), the way of applying the load to CFST columns (through the concrete core or through the entire cross-section), the bond strength between a...
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Biomechanical testing of bioactive bone cements – a comparison of the impact of modifiers: antibiotics and nanometals
PublikacjaApart from its bone filler and fracture stabilizing function, bone cement can be used as a carrier of bioactive substances, and such modified bone cement can protect the implant against microorganisms, treat local infections and combat bacteria introduced during the surgical procedure. In this paper, the effects of modifying antibiotics and nanosilver on the biomechanical properties of bone cement were examined. The following tests...
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Design and numerical testing of 5-box gfrp shell footbridge
PublikacjaThe paper formulates new design conditions for composite footbridges, taking into account the material and structural specificity of these objects, i.e. the strength condition, the serviceability condition and the frequency condition. A GFRP composite footbridge labelled with CFB2 code has been designed, with the original superstructure in the form of an opened-closed 5-box girder. The foot and cycle track bridge is simply supported,...
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An innovative approach to the forecasting of energetic effects while wood sawing
PublikacjaIn 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, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture...
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SIMULATION OF PROCEED® SURGICAL MESH APPLIED TO VENTRAL HERNIA REPAIR
PublikacjaIn the present research, Proceed® implant is considered. The system is subjected to short-time dynamic pressure load, similar to post-operative cough naturally occurring in human abdomen. The model refers to a clinical case of 5cm of hernia operated by Proceed implant fixed by 15 joints every 3cm around the orifice. The simulations of the implanted mesh are performed by means of the Finite Element Method. The implant is modelled...
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Cost-Effective and Sufficiently Precise Integration Method Adapted to the FEM Calculations of Bone Tissue
PublikacjaThe technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar...
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An Innovative Approach to the Forecasting of Energetic Effects While Wood Sawing
PublikacjaIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specifi c cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture mechanics....
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Wpływ wybranych parametrów środowiska na przebieg degradacji rur okładzinowych ze stali P110
PublikacjaMateriały używane na orurowanie odwiertów w poszukiwaniu i wydobyciu ropy i gazu poddawane są niekorzystnym warunkom eksploatacji takich jak: podwyższona temperatura, wysokie ciśnienie, turbulentny przepływ korozyjnych cieczy z zawieszonymi cząstkami stałymi. Jednym z gatunków stali używanych do produkcji rur okładzinowych jest stal P110 (za normą API 5CT) będąca stalą średnio-węglową, niskostopową o wysokiej wytrzymałości. Celem...
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Physical and sealing properties of BaO–Al2O3–SiO2–CaO–V2O5 glasses for solid oxide fuel cell applications
PublikacjaIn this study, the properties of BaO–Al2O3–SiO2 (SAB) glasses incorporated with CaO and V2O5 as the network modifier and additive, respectively, are evaluated. The electrical resistivities of the glasses decrease upon the addition of CaO but increase upon increasing their V2O5 content because the V5+ species lower the ionic mobility of the glasses. The addition of V2O5 improves the wettability of the glasses on the Crofer 22 APU...
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Effect of Particle Size of Fly Ash Microspheres (FAMs) on the Selected Properties of Concrete
PublikacjaThis paper presents the investigations of selected properties of concrete containing two fractions of fly ash microspheres (FAMs) with grain size up to 200 μm and up to 500 μm. Concrete mixtures with ordinary Portland cement and three substitution rates of cement by FAMs, 1.3%, 2.0%, and 2.6%, were investigated. For all concrete mixes, the constant water–binder ratio (w/b) equal to 0.50 was used. The research program included the...
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About Unusual Diffraction and Thermal Self-Action of Magnetosonic Beam
PublikacjaThe dynamics of slightly diverging two-dimensional beams whose direction forms a constant angle θ with the equilibrium straight magnetic strength is considered. The approximate dispersion relations and corresponding links which specify hydrodynamic perturbations in confined beams are derived. The study is dedicated to the diffraction of a magnetosonic beam and nonlinear thermal self-action of a beam in a thermoconducting gaseous plasma....
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublikacjaMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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Study on Microstructural Characterization, Mechanical Properties and Residual Stress of GTAW Dissimilar Joints of P91 and P22 Steels
PublikacjaThis article deals with the dissimilar joining of two different grade Cr-Mo steel (2.25Cr-1Mo: P22 and modified 9Cr-1Mo: P91) for power plant application. The dissimilar butt-welded joint was produced for conventional V groove design by using the gas tungsten arc welding (GTAW) process with the application of an ERNiCrMo-3 Ni-based super alloy filler. A microstructure characterization was performed to measure the inhomogeneity...
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Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
PublikacjaLarge deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation...
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Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study
PublikacjaThis article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron...
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The Use of Direct Shear Test for Optimization of Interlayer Bonding Under a Poroelastic Layer
PublikacjaPoroelastic Road Surfaces (PERS) are characterised by porous structure with air void content of 20% or higher and stiffness almost 10 times lower than that of a standard asphalt course. Such properties enable noise reduction by up to 12 dB in comparison to SMA 11 mixture. However, the disadvantage of a poroelastic pavement is its low durability, which partially results from delamination from the lower layer. The paper aims to investigate...
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Bitumen-Based Poroelastic Pavements: Successful Improvements and Remaining Issues
PublikacjaThis article presents the development process of designing and testing poroelastic pavement based on highly polymer-modified bitumen. Poroelastic wearing course was composed of mineral and rubber aggregate mixed with highly polymer-modified bitumen, in contrast to previous trials, during which polyurethane resins were mainly used as binder, which led to several serious technological problems concerning difficult production, insufficient...
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Evaluation of the glycerolysis process and valorisation of recovered polyol in polyurethane synthesis
PublikacjaIn this study, the glycerolysis of polyurethane (PU) foam and the applicability of obtained glycerolysate (GLY) for cast PUs were investigated. It was found that crude glycerine with purity grade of 84% might be successfully used for the glycerolysis. The optimal conditions were determined as follows: reaction time of 60 min at 220 °C using dibutyltin dilaurate catalyst (0.5%). Moreover, the purification of GLY by means of liquid-liquid...
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The thermal effort during marine steam turbine flooding with water
PublikacjaThe work discussed an extreme case of cooling a steam turbine. The ship's steam turbine was used as an example. In marine transport units with low-speed engines dominate, however, there are also units with steam turbines. An example of analysed marine steam turbine is shown in Fig. 1. When considering the issue of cooling steam turbines, it is necessary to estimate the extreme conditions that may occur during operation of the turbine....
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A study on diagnosing both isotropic and orthotropic, intentionally damaged laminates
PublikacjaBeing the most detrimental mode in laminated structures, delamination initially degrades local structural strength, and lastly causes global structural failure, thus necessitating delamination identification at its incipient stages. For identification purposes, a comprehensive numerical and experimental study on delamination within both the laminated isotropic acrylic-glass and orthotropic epoxyglass plates is presented. As the...
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Evaluation of the significance of the effect of the active cross-sectional area of the inlet air channel on the specific enthalpy of the exhaust gas of a diesel engine using statistics F of the Fisher-Snedecor distribution
PublikacjaThis paper presents the application of Fisher-Snedecor distribution F statistics to assess the significance of the influence of changes in the active cross-sectional area of the inlet air channel (Adol) flow in a diesel engine on the observed diagnostic parameter determined on the basis of measurements of the quick changing exhaust gas temperature in the outlet channel, which is the specific enthalpy of the exhaust gas stream within...
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Hydration of Oxometallate Ions in Aqueous Solution
PublikacjaThe strength of hydrogen bonding to and structure of hydrated oxometallate ions in aqueous solution have been studied by double difference infrared (DDIR) spectroscopy and large-angle X-ray scattering (LAXS), respectively. Anions are hydrated by accepting hydrogen bonds from the hydrating water molecules. The oxygen atom of the permanganate and perrhenate ions form weaker and longer hydrogen bonds to water than the hydrogen bonds...
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Shape-Memory Polyurethane Polymers
PublikacjaPolyurethanes (PUs) are one of the most widely used polymers in research and industry. They can be synthesized from chemical sources and natural sources. PUs are a very useful class of polymers and exhibit many desirable properties that can be exploited in various applications. PUs are formed by the reaction between polyols and isocyanates. A wide variety of polyols and isocyanates are available for synthesis, and hence we can...
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Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
PublikacjaThis study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol...
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Image-based numerical modeling of the tensile deformation behavior and mechanical properties of additive manufactured Ti–6Al–4V diamond lattice structures
PublikacjaThis work concerns the numerical modeling of the deformation process and mechanical properties of structures obtained by the additive method laser power bed fusion (LPBF). The investigation uses diamond structures of Ti–6Al–4V titanium implantation alloy with various relative densities. To model the process of tensile deformation of the materials, geometric models were used, mapping the realistic shape of the examined structures....
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Preparation of Well-Compatibilized PP/PC Blends and Foams Thereof
PublikacjaThe performance of polypropylene-poly(ethylene brassylate) block and graft copolymers and a polypropylene-polycaprolactone graft copolymer as compatibilizers for polypropylene-rich polypropylene/bisphenol A polycarbonate (PP/PC, 80/20 wt/wt) blends was elucidated. The copolymers were synthesized either by metal-catalyzed ring-opening polymerization or transesterification of a presynthesized polyester, initiated by hydroxyl-functionalized...
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Performance Characteristics of a Micro-turbine, International
Publikacja. In the paper a design of a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of particular experimental investigations and numerical calculations are shown, followed by conclusions. The co-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The values of the main cycle parameters were as follows:- heat...
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Experimental comparison of hydrodynamic thrust bearings with different pad surface materials
PublikacjaBabbitt is the material most frequently used as the pad surface material for hydrodynamic bearings operating at usual operating conditions. It shows many advantages important for safe bearing operation, as for example: low friction coefficient, corrosion resistance, fair mechanical properties and outstanding conformability. On the other hand, it is not free from disadvantages, such as limited fatigue strength or limited resistance...
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Clay-filled starch films. Part I: Effect of clay kind and glycerol concentration on functional properties of composites
PublikacjaThe aim of this work was to improve the mechanical and water barrier properties of composite filmsprepared from starch and clays, plasticized with glycerol at different concentrations. The effects ofhydrophilic Closite Naþand Nanomer PGV were compared with that exerted by organicallymodifiedmorehydrophobicNanofil2 and NanoBent ZR-1. The antimicrobial activity of compositescontaining hydrophobic clays was also investigated. The hydrophilic...