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Search results for: core-shell nanoparticles
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Synthesis of bimetallic Co–Pt/cellulose nanocomposites for catalytic reduction of p-nitrophenol
PublicationIn this study, bimetallic nanoparticles (NPs) of Co–Pt anchored on cellulose nanofibers (CNFs) for catalytic applications were synthesized via a sonochemical approach. The electro-spinning technique was employed for the synthesis of CNFs from cellulose acetate. The thorough characterization of synthesised Co–Pt/CNF nanocomposites was performed with the help of scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR)...
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Influence of Different Nanometals Implemented in PMMA Bone Cement on Biological and Mechanical Properties
PublicationCemented arthroplasty is a common process to fix prostheses when a patient becomes older and his/her bone quality deteriorates. The applied cements are biocompatible, can transfer loads, and dampen vibrations, but do not provide antibacterial protection. The present work is aimed at the development of cement with antibacterial effectivity achieved with the implementation of nanoparticles of different metals. The powders of Ag,...
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Support Materials of Organic and Inorganic Origin as Platforms for Horseradish Peroxidase Immobilization: Comparison Study for High Stability and Activity Recovery
PublicationIn the presented study, a variety of hybrid and single nanomaterials of various origins were tested as novel platforms for horseradish peroxidase immobilization. A thorough characterization was performed to establish the suitability of the support materials for immobilization, as well as the activity and stability retention of the biocatalysts, which were analyzed and discussed. The physicochemical characterization of the obtained...
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Homoleptic mono-, di-, and tetra-iron complexes featuring phosphido ligands: a synthetic, structural, and spectroscopic study
PublicationWe report the first series of homoleptic phosphido iron complexes synthesized by treating either the β-diketiminato complex [(Dippnacnac)FeCl2Li(dme)2] (Dippnacnac = HC[(CMe)N(C6H3-2,6-iPr2)]2) or [FeBr2(thf )2] with an excess of phosphides R2PLi (R = tBu, tBuPh, Cy, iPr). Reaction outcomes depend strongly on the bulkiness of the phosphido ligands. The use of tBu2PLi precursor led to an anionic diiron complex 1 encompassing a planar...
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Magnetic field mapping along a NV-rich nanodiamond-doped fiber
PublicationIntegration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows...
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Crystal and electronic structures of Ni(II) silanethiolates containing flexible diamine ligands
PublicationFive nickel(II) complexes containing aliphatic diamines and tri-tert-butoxysilanethiolate ligand have been synthesized for the purpose of studying their structural, spectral (IR, UV–Vis, HF EPR) and thermal properties. Complexes (1)–(5) have been prepared in high yield by reactions of [Ni{SSi(OtBu)3}2(NH3)(H2O)] with 1.3-propanediamine (L1), 1,6-hexanediamine (L2), or 1,7-heptanediamine (L3). The X-ray structures were determined...
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Generation of large finite-element matrices on multiple graphics processors
PublicationThis paper presents techniques for generating very large finite-element matrices on a multicore workstation equipped with several graphics processing units (GPUs). To overcome the low memory size limitation of the GPUs, and at the same time to accelerate the generation process, we propose to generate the large sparse linear systems arising in finite-element analysis in an iterative manner on several GPUs and to use the graphics...
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NEW EXPERIENCES IN DIKE CONSTRUCTION WITH SOIL-ASH COMPOSITESAND FINE-GRAINED DREDGED MATERIALS
PublicationThe supporting structure inside a coastal dike is often made of dredged non-uniform sand with good compaction proper-ties. Due to the shortage of natural construction material for both coastal and river dikes and the surplus of different processed mate-rials, new experiments were made with sand-ash mixtures and fine-grained dredged materials to replace both dike core and dikecover materials resulting in economical, environmentally...
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Open-Source Coprocessor for Integer Multiple Precision Arithmetic
PublicationThis paper presents an open-source digital circuit of the coprocessor for an integer multiple-precision arithmetic (MPA). The purpose of this coprocessor is to support a central processing unit (CPU) by offloading computations requiring integer precision higher than 32/64 bits. The coprocessor is developed using the very high speed integrated circuit hardware description language (VHDL) as an intellectual property (IP) core. Therefore,...
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Migration of container terminals as their natural process of evolution: Case study of Gdańsk and Gdynia ports
PublicationThe paper proposes a theoretical model of container terminals and container port development, based on the life cycle theory, threshold theory and catastrophe theory, and in references to Kuznets' swings (interpreted as waves of infrastructural investments), and Kondratiev long economic waves. The aim of this model is to explain the development process of a container terminal and a port within one technological generation, as...
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Determinants of the incidence of non-academic staff in European and US HEIs
PublicationIn this article, we contribute to the scant literature covering quantitative studies on the determinants of the non-academic staff incidence in higher education institutions by analysing how the proportion of non-academic staff is related to key features such as size, prestige, year of foundation and financial structure of universities. We apply nonlinear regression analysis to compare HEIs across Europe and the USA, taking into...
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ZINTEGROWANE ZARZĄDZANIE STREFĄ PRZYBRZEŻNĄ ORAZ URBANISTYKA – PROJEKT NOWYCH SPECJALNOŚCI NA KIERUNKU GOSPODARKA PRZESTRZENNA NA POLITECHNICE GDAŃSKIEJ
PublicationNa studiach II stopnia na kierunku gospodarka przestrzenna na Wydziale Architektury Politechniki Gdańskiej w 2017 r. otwierane są dwie specjalności: urbanistyka i zintegrowane zarządzanie strefą przybrzeżną. Trzon programu studiów dla obu specjalności jest wspólny i oparty na dotychczasowych standardach kształcenia na tym kierunku. Specjalność zintegrowane zarządzanie strefą przybrzeżną jest odpowiedzią na konieczność wprowadzenia...
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Joints Of Steel Sandwich Structures
PublicationSteel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell...
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Transition-Metal-Promoted Oxidative Cyclization To Give 1,2,4-Trisubstituted Carbazole Scaffolds
PublicationHerein, we describe the synthesis of a 1,2,4-trisubstituted carbazole core from 5-(1H-indol-3-yl)-3-oxopentanoic acid esters or amides. For oxidative cyclization, we tested two different approaches. First, we used manganese triacetate as a conventional moderate oxidizer to ensure the radical course of the reaction. Second, we examined the use of a more complex oxidizing agent I2/Me(OTf)3. In both cases, formation of a fused-ring...
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Definition of urban regeneration projects in Russian cities
PublicationUrban regeneration is extremely important process for Russian cities, which faced to the challenges of post-industrial economy. In an attempt, to explain needs of urban regeneration in Russian megacities author analyzed the social and economic trends and some historic features of Russian cities development. The article identified the key areas for regeneration such as the regeneration of historic core, the regeneration of the urban...
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The impact of end-user participation in IT projects on product usability
PublicationMany companies implementing new IT projects encounter numerous problems with ensuring good final product usability. The strong market competition they experience often results in necessity of undertaking difficult decisions with regard to cost minimization. This may force cuts in usability expertise and consulting, most often by limiting end-user participation in the project. However, it may also result in serious consequences...
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What determines export diversification in the development process? Empirical assessment.
PublicationThis paper assesses the role played by country-specific factors as determinants of relative export diversification. Using a panel data set for 60 countries and 20 years (1985–2004), we confirm that even after clearing out differences in income per capita, cross-country variability in the degree of export diversification is significant. In general, apart from per capita income, features influencing the size of accessible markets...
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Biocompatibility and Bioactivity of Load-Bearing Metallic Implants
PublicationThe main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation;...
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Export Diversification and Development - Empirical Assessment
PublicationThis paper assesses the role played by country specific factors as determinants of exports' diversification process. Using a panel data-set for 60 countries and twenty years (1985-2004) we confirm that even after clearing out differences in income per capita, cross section variability in the degree of exports' diversification is significant. In general, apart from per capita income, variables influencing the size of accessible...
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LOW COST MEASUREMENT MODULE FOR MATRIX OF AMPEROMETRIC GAS SENSOR
PublicationThis paper describes an amperometric sensor module for gas concentration measurement. A module can be used for many types of electrochemical gas sensors without major hardware changes. Device is based on AVR ATmega8 microcontroller. As signal processing circuit a specialized integrated circuit LMP9l000 configurable via I2C interface is used. The concept of a measuring system composed of several modules dedicated for a gas sensors...
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Variability of relationship between cities and nature in landscape architecture= Zmienność relacji miedzy miastem a naturą na przykładzie architektury krajobrazu miast
PublicationInterpreting and creating the relations between nature and city are the process of learning which is a subject of permanent conceptualization. It is characterized by the culutrality due to human nature and own ability to perceive oneself in the context of the relationship between own environmental and cultural nature. The way of interpreting the nature and providing it with different features affected significantly the development...
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Simplified stability analysis of steel cylindrical silos with corrugated walls and vertical columns
PublicationIn the paper a simplified stability analysis of steel cylindrical silos composed of corru¬gated walls and vertical open-sectional columns was proposed. The whole 3D silo was modeled as a single column resting on elastic foundation provided by the silo walls. In proposed formula for the calculation of the foundation stiffness the curvature of the silo walls was taken into account. Three different analyses were carried out using...
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Numerical analysis of a temporary steel grandstand
PublicationThe purpose of this paper is to present the results of the numerical analysis focused on the response of the temporary steel scaffolding grandstand subjected to human-induced vibrations due to jumping. Shell as well as beam elements have been used in the numerical model. Its first stage has involved conducting modal analysis in order to determine the modes of free vibrations and the corresponding natural frequencies for the empty...
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Response of a steel tank during earthquakes and mining tremors - experimental investigation
PublicationCylindrical steel tanks are very popular shell structures used to store the products of chemical and petroleum industries. Any failure might have disastrous consequences, therefore their safety and reliability is essential. Earthquakes are the most dangerous and also the most unpredictable dynamic loads acting on such structures. On the other hand, mining tremors are usually considered to be less severe due to lower acceleration...
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Extended non-linear relations of elastic shells undergoing phase transitions
PublicationThe non-linear theory of elastic shells undergoing phase transitions was proposed by two first authors in J. Elast. 79, 67-86 (2004). In the present paper the theory is extended by taking into account also the elastic strain energy density of the curvilinear phase interface as well as the resultant forces and couples acting along the interface surface curve itself. All shell relations are found from the variational principle of...
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Wpływ smarowności na działania układu tribologicznego (impact of lubricity on the tribological system action)
Publicationthe paper presents analysis and evaluation, based on tests results, of the impact of lubricity of the used lubricating oils (shell argina t 40) on the action of boundary layer of sulzer 6zl40/48 engines aboard the ''włocławek'' sea-going ship. for comparison purposes, the same oils were tested with the ceramizer four-stroke engine (all types of the vidar four-stroke engines) regeneration agent added. so understood boundary layer...
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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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Experimental investigation of two-phase thermosyphon heat exchanger charged with acetone
PublicationThis paper presents thermal characteristics of prototype of a two-phase thermosyphon heat exchanger (TPTHEx) charged with acetone as a working fluid. The TPTHEx consists of two horizontal cylindrical vessels connected by two risers and a downcomer. Tube bundles placed in the lower and upper cylinders work as an evaporator and a condenser, respectively. The tested TPTHEx operates in a vacuum. Therefore, the working liquid is boiled...
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Examination of selected failure criteria with asymmetric shear stresses in the collapse analysis of laminated shells
PublicationThe paper is concerned with failure analysis of composite shells performed with the usage of the nonlinear 6‐parameter shell theory with drilling rotation degree of freedom. This special theory embodies naturally unlim-ited translations and rotations and is suitable for analysis of irregular shells for instance with various, partic-ularly orthogonal, intersections. The presence of the drilling rotation is inherently accompanied...
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Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublicationThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
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Measurement of temperature-dependent viscosity and thermal conductivity of alumina and titania thermal oil nanofluids
PublicationThe results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e. thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil was selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1% and 5% by weight within temperature range from 20°C to...
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Nanosorbents as Materials for Extraction Processes of Environmental Contaminants and Others
PublicationThe aim of this work focuses on the application of nanomaterials (NMs) in different sorp- tive extraction techniques for the analysis of organic contaminants from environmental samples of distinct matrix compositions. Without any doubt, the integration of specific NMs such as carbona- ceous nanomaterials, magnetic nanoparticles (MNPs), metal–organic frameworks (MOFs), silica na- noparticles, and ion-imprinted NPs with so lid-phase...
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Approximation of Fractional Order Dynamic Systems Using Elman, GRU and LSTM Neural Networks
PublicationIn the paper, authors explore the possibility of using the recurrent neural networks (RNN) - Elman, GRU and LSTM - for an approximation of the solution of the fractional-orders differential equations. The RNN network parameters are estimated via optimisation with the second order L-BFGS algorithm. It is done based on data from four systems: simple first and second fractional order LTI systems, a system of fractional-order point...
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Modern Platform for Parallel Algorithms Testing: Java on Intel Xeon Phi
PublicationParallel algorithms are popular method of increasing system performance. Apart from showing their properties using asymptotic analysis, proof-of-concept implementation and practical experiments are often required. In order to speed up the development and provide simple and easily accessible testing environment that enables execution of reliable experiments, the paper proposes a platform with multi-core computational accelerator:...
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Winding function approach based design of novel five-phase brushless doubly fed induction generator
PublicationThe paper presents the concept of the new design of the five-phase brushless doubly fed induction generator. The generator is dedicated to the modern wind turbine. The innovative design approach uses a five-phase power supply from the stator control winding side of the generator with a stator three-phase classic power winding. The research results presented indicate that the electromagnetic coupling between the control and power...
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Failure characterisation of sandwich beams using integrated acoustic emission and digital image correlation techniques
PublicationThe paper presents the experimental study of the failure behaviour of sandwich beams subjected to bending. The samples examined are sandwich beams made of polyethylene terephthalate foam core and glass fibre-reinforced polymer laminate face sheets. In a series of experiments, it has been proposed to integrate diagnostic techniques with acoustic emission and digital image correlation to accurately track the cracking process on the...
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Experimental tests and numerical simulations of full scale composite sandwich segment of a foot- and cycle- bridge
PublicationIn the paper experimental tests and numerical simulations of a full cross-section segment of ultimately designed foot-and cycle-bridge are presented. The experimental tests were conducted on element with length reduced to 3 m and unchanged (target) cross-section dimensions. The external skin of structure is GFRP laminate while internal core is PET foam. Several quasi-static tests were performed using hydraulic cylinder to generate...
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Visual Data Encryption for Privacy Enhancement in Surveillance Systems
PublicationIn this paper a methodology for employing reversible visual encryption of data is proposed. The developed algorithms are focused on privacy enhancement in distributed surveillance architectures. First, motivation of the study performed and a short review of preexisting methods of privacy enhancement are presented. The algorithmic background, system architecture along with a solution for anonymization of sensitive regions of interest...
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Gaze tracking in multi-display environment
PublicationThis paper presents the basic ideas of eye and gaze tracking in multiple-display environment. The algorithm for display detection and identification is described as well as the rules for gaze interaction in multi display environment. The core of the method is to use special LED markers and eye and scene tracking glasses. Scene tracking camera registers markers position which is then represented as a cloud of points. Analyzing the...
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Cytocompatibility, antibacterial, and corrosion properties of chitosan/polymethacrylates and chitosan/poly(4‐vinylpyridine) smart coatings, electrophoretically deposited on nanosilver‐decorated titania nanotubes
PublicationThe development of novel implants subjected to surface modification to achieve high osteointegration properties at simultaneous antimicrobial activity is a highly current problem. This study involved different surface treatments of titanium surface, mainly by electrochemical oxidation to produce a nanotubular oxide layer (TNTs), a subsequent electrochemical reduction of silver nitrate and decoration of a nanotubular surface with...
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Influence of dispersed phase content on the mechanical properties of electroless nanocomposite Ni-P/Si3N4 and hybrid Ni-P/Si3N4/graphite layers deposited on the AW-7075 alloy.
PublicationThe article presents the results of mechanical testing of Ni-P/Si3N4 nanocomposite and hybrid Ni-P/Si3N4/graphite coatings deposited on AW-7075 aluminum alloy using the chemical reduction method. In terms of mechanical testing, microhardness was measured, and surface roughness and adhesion of the coatings to the aluminum substrate were determined using the “scratch test” method. The surface morphology of the deposited layers was...
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Polyurethane/Silane-Functionalized ZrO2 Nanocomposite Powder Coatings: Thermal Degradation Kinetics
PublicationA polyurethane (PU)-based powder coating reinforced with vinyltrimethoxysilane (VTMS)-functionalized ZrO2 nanoparticles (V-ZrO2) for thermal stability was developed. Chemical structure, microstructure and thermal degradation kinetics of the prepared coatings were investigated. The peak of aliphatic C–H vibrating bond in the Fourier transform infrared (FTIR) spectrum of V-ZrO2 was a signature of VTMS attachment. Scanning electron...
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Highly crystalline colloidal nickel oxide hole transport layer for low-temperature processable perovskite solar cell
PublicationHighly crystalline NiOX usually requires high annealing temperature (>300 °C) which is incompatible with flexible substrate and might consume high amount of energy. Herein, we demonstrate a facile emulsion process to synthesize highly crystalline, low temperature deposition (<150 °C) and solution processable NiOx nanoparticles (NPs) as a hole transport layer for the perovskite solar cells (PVSCs). A novel surfactant of tetramethylammonium...
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Highly antifouling polymer-nanoparticle-nanoparticle/polymer hybrid membranes
PublicationWe introduce highly antifouling Polymer-Nanoparticle-Nanoparticle/Polymer (PNNP) hybrid membranes as multi-functional materials for versatile purification of wastewater. Nitrogen-rich polyethylenimine (PEI)-functionalized halloysite nanotube (HNT-SiO2-PEI) nanoparticles were developed and embedded in polyvinyl chloride (PVC) membranes for protein and dye filtration. Bulk and surface characteristics of the resulting HNT-SiO2-PEI...
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Role of Sports Facilities in the Process of Revitalization of Brownfields
PublicationThe paper gives an evidence that building a large sports facility can generate beneficial urban space transformation and a significant improvement in the dilapidated urban areas. On the basis of theoretical investigations and case studies it can be proved that sports facilities introduced to urban brownfields could be considered one of the best known large scale revitalization methods. Large urban spaces surrounding sport facilities...
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MEASUREMENT OF TEMPERATURE-DEPENDENT VISCOSITY AND THERMAL CONDUCTIVITY OF ALUMINA AND TITANIA THERMAL OIL NANOFLUIDS
PublicationIn this study results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e. thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil is selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1% and 5% by weight within temperature range from...
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Performance of the flat plate solar collector operated with water-Al2O3 nanofluid
PublicationThe paper discusses the effect of application of water-Al2O3 nanofluid, as a working fluid, on the efficiency of a flat plate solar collector. The mass concentration of nanoparticles was 0.1%, 0.2% and 0.4%. The tests were conducted for two values of radiation of about 1050 W/m2 and 400 W/m2, and volume flow rates of 60 l/h, 120 l/h and 170 l/h. The efficiency was calculated according to recommendations of the Polish Standard....
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Molecular dynamics studies of polyurethane nanocomposite hydrogels
PublicationPolyurethane PEO-based hydrogels have a broad range of biomedical applicability. They are attractive for drug-controlled delivery systems, surgical implants and wound healing dressings. In this study, a PEO based polyurethane hydrogels containing Cloisite R 30B, an organically modified clay mineral, was synthesized. Structure of nanocomposite hydrogels was determined using XRD technique. Its molecular dynamics was studied by means...
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A XAS study of a highly diluted Pt electrocatalyst operating in PEM fuel cells
PublicationWe present an X-ray absorption spectroscopy (XAS) study of a low Pt content catalyst layer(Pt loading 0.1 mg c2) operating at the cathode of a proton exchange membrane fuel cell(PEMFC). This catalyst is based on the use of a mesoporous inorganic matrix as a support forthe catalyst Pt nanoparticles. Due to the high Pt dilution, in situ measurements of itsstructural properties by XAS are challenging and suitable experimental strategies...
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Key logistics processes in project management based on organisation of an international training session-case study
PublicationImprovement of processes, including the logistics processes forms one of the essential aspects of modern business entities functioning. Search for the solutions allowing for quicker and less costly method of realisation of particular activities in highly significant, especially in the conditions of a dynamically changing environment in which the organisations have to function. It is a natural field occuring principally both in...