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Microstructure and residual stresses in surface coatings with PTFE reservoirs
PublikacjaThe paper presents the results of experimental study into the microstructure and changes in residual stresses resulting from sliding and rolling/sliding loaded interaction between metallic surface coatings with embedded PTFE reservoirs and various counter faces. It was found that before testing surface coatings had compressive residual stresses. Molybdenum coating with all types of PTFE reservoirs displayed, as a result of testing,...
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Biological and mechanical research of titanium implants covered with bactericidal coating
PublikacjaThe paper concerns the biological and mechanical properties of titanium implants with an antibacterial coating. The Ti13Zr13Nb alloy samples were coated with hydroxyapatite (HAp) coatings using the electrophoretic deposition technique (EPD). Subsequently, the surface of the samples was modified with silver, copper, and nickel nanoparticles by the immersion method. Different titanium sample types (i.e. HAp-only and nanometals-enriched...
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Inverse determination of sliding surface temperature based on measurements by thermocouples with account of their thermal inertia
PublikacjaThis study developed an inverse heat conduction algorithm to determine temperature at a sliding surface taking account of thermocouple thermal inertia. The direct heat conduction problem was solved analytically based on the Laplace integral transform approach. The inverse algorithm was applied to the problem of friction of a brake material against a steel. The experiments were conducted on a pin-on-disc tribometer for three short-time...
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Susceptibility to Degradation in Soil of Branched Polyesterurethane Blends with Polylactide and Starch
PublikacjaA very important method of reducing the amount of polymer waste in the environment is the introduction to the market of polymers susceptible to degradation under the influence of environmental factors. This paper presents the results of testing the susceptibility to degradation in soil of branched polyesterurethane (PUR) based on poly([R,S]-3-hydroxybutyrate) (R,S-PHB), modified with poly([D,L]-lactide) (PLA) and starch (St). Weight...
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Polarization-dependent optical absorption in phosphorene flakes
PublikacjaThe interest of 2D materials is constantly increasing because of their very attractive mechanical, electrical and optical parameters. They have been used in many applications, e.g. photodetectors, sensors, modulators, insulators. One of the recently discovered 2D materials is phosphorene. In contrast to graphene, phosphorene has a direct bandgap tuned by numbers of layers in the 2D structure. The phosphorene flakes are strongly...
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DEM-FEM model of highly saturated soil motion due to seepage force
PublikacjaArtykuł poświęcono nowej propozycji rozwiązania problemu modelowania zjawiska transportu, które występuje wewnątrz wysoko-nawodnionego gruntu ziarnistego na skutek ciśnienia spływowego. Teoria oparta została na połączeniu metody elementów skończonych (FEM - Finite Element Method) - rozwiązania równań poro-elastycznych oraz metody poszczególnych elementów (DEM - Distinct Element Method), które dały podwójny model numeryczny. FEM...
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On local buckling of cold-formed channel members
PublikacjaThe paper deals with local buckling of the compressed flanges of cold-formed thin-walled channel beams subjected to pure bending or axially compressed columns. Arbitrarily shaped flanges of open cross-sections and the web-flange interactions are taken into account. Buckling deformation of a beam flange is described by displacement related to torsion of the flange about the line of its connection with the web. Total potential energy...
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Disaster-Resilient Routing Schemes for Regional Failures
PublikacjaLarge-scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a minimum geographical...
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Thermal visualization of Ostwald-de Waele liquid in wavy trapezoidal cavity: Effect of undulation and amplitude
PublikacjaThe present study is concerned with the numerical simulations of Ostwald-de Waele fluid flow in a wavy trapezoidal cavity in the presence of a heated cylinder situated at the center of the cavity. The work consists in characterizing the mixed convection as a function of the intensity of heat flow. The flow behaviour and temperature distribution in a cavity are the main focus of this study. The lower wall of the cavity is fixed...
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The influence of selected strain-based failure criteria on ship structure damage resulting from a collision with an offshore wind turbine monopile
PublikacjaOffshore wind farms are developing well all over the world, providing green energy from renewable sources. The evaluation of possible consequences of a collision involves Finite Element computer simulations. The goal of this paper was to analyse the influence of selected strain-based failure criteria on ship damage resulting from a collision with an offshore wind turbine monopile. The case of a collision between an offshore supply...
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The methodology of design of axial clearances compensation unit in hydraulic satellite displacement machine and their experimental verification
PublikacjaA new methodology of calculating the dimensions of the axial clearance compensation unit in the hydraulic satellite displacement machine is described in this paper. The methods of shaping the compensation unit were also proposed and described. These methods were used to calculate the geometrical dimensions of the compensation field in an innovative prototype of a satellite hydraulic motor. This motor is characterized by the fact...
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Wybrane zagadnienia budowy skojarzonych układów energetycznych zasilanych biogazem
PublikacjaW referacie przedstawiono problematykę wykorzystania biogazu jako paliwo do kogeneracyjnych zespołów prądotwórczych z tłokowymi silnikami spalinowymi jako element realizacji produkcji energii elektrycznej z odnawialnych źródeł energii. Wskazano na możliwości optymalnego rozwiązania konstrukcji układów kogeneracyjnych z punktu widzenia mozliwie jak najszerszej utylizacji ciepła odpadowego z silników napędzających prądnicę.
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Calculation of self and mutual inductances of the switched reluctance machine mathematical model.
PublikacjaA mathematical model of the switched reluctance machine (SRM) in a drive system obtained using Lagrange's energy method and a method of calculation of self and mutual inductances of the SRM are presented in the paper. The self and mutual inductances are elements of Lagrange's function in generalised coordinates and have been calculated using the finite element method (FEM). Selected calculation results for the particular machine...
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Przemiany strukturalne i reforma systemu bankowego w Polsce
PublikacjaW pracy przedstawiono przemiany strukturalne w systemie bankowym w Polsce, jako element dostosowania się do wymogów stawianych przez Unię Europejską. Procesy systemowych i strukturalnych przekształceń w systemie bankowym rozpatrzono jako konieczność stworzenia bezpiecznego i efektywnego systemu bankowego, pozwalającego bankom komercyjnym na funkcjonowanie w warunkach konkurencji i ryzyka.
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Przebudowa Falochronu Wschodniego w ramach modernizacji wejścia do Portu Wewnętrznego w Gdańsku
PublikacjaModernizacja wejścia do Portu Wewnętrznego jako istotny element poprawy konkurencyjności Portu Gdańsk. Główne założenie przebudowy to umożliwienie bezpiecznego wprowadzania i obsługi statków o zanurzeniu T=10,6m.Krótka historia wejścia do Portu zewnętrznego oraz dokładny opis przeprowadzonej w latach 2011-2012 przebudowy Falochronu Wschodniego przy wejściu do Portu Wewnętrznego.
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Analysis of Crash Computation on a Basis of the Pronciple of Linear Momentum and Kinetic Energy
PublikacjaThe article shows the calculation of a vehicle crash with a fixed pile, modelled by the finite element method. There were compared during the crash simulations changes in kinetic energy, as well as – changes in linear momentum and its derivative, with respect to time. Calculations were made in the HyperWorks CAE software environment. The obtained results show influence of various body parts and devices of the deceleration on...
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Diagnostics of thermal processes in antenna systems of broadcast stations
PublikacjaDiagnostics is an important element associated with the operation of a radio antenna systems, allowing earlier detection of potential damage. Thermography is one of the diagnostic tools, which allows for non-invasive assessment of technical condition. It brings together both financial savings associated with the removal of the damage and the potential effects caused by it. The article presents an example of using a thermal imaging...
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Koncepcja trójmiejskiego inteligentnego systemu transportu TRISTAR.
PublikacjaZastosowanie Inteligentnych Systemów Transportu jest jednym ze sposobów udoskonalenia systemów transportowych. Zgodnie z ustaleniami podjętymi w Sopocie w 2002 roku, miasta Aglomeracji Trójmiejskiej przystąpiły do opracowania koncepcji systemów zarządzania ruchem na podległych sobie drogach. W niniejszym referacie przedstawiono pierwszy element prac koncepcyjnych, jakim jest system aglomeracyjny.
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Evaluation of information technology projects
PublikacjaOcena projektów IT. W artykule zaproponowano nową platformę oceny projektów badawczych związanych z technologiami informacyjnymi. Metodę oceny oparto na bazie wiedzy historycznej związanej z projektami sponsorowanymi przez Unię Europejską. Jako główny element aparatu oceny zaproponowano bazę wiedzy w postaci zasad produkcji i wnioskowanie oparte na teorii zbiorów rozmytych.
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Failure Analysis of footbridge made of composite materials
PublikacjaFinite element method analysis of a pedestrian footbridge made of sandwich material is presented. The internal structure of the material is modelled as a structural shell assuming the Equivalent Single Layer approach (ESL). Two FEM commercial codes are employed. The response of the structure is studied in order to determine the load level that activates Hashin and Tsai-Wu failure criteria. Some practical aspects of designing footbridges...
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Linear Micropolar Elasticity Analysis of Stresses in Bones Under Static Loads
PublikacjaWe discuss the finite element modeling of porous materials such as bones using the linear micropolar elasticity. In order to solve static boundary-value problems, we developed new finite elements, which capture the micropolar behavior of the material. Developed elements were implemented in the commercial software ABAQUS. The modeling of a femur bone with and without implant under various stages of healing is discussed in details
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Modal FEM Analysis of Ferrite Resonant Structures
PublikacjaThe finite-element method (FEM) is applied for modal analysis of ferrite-loaded spherical resonators. To improve the efficiency of the numerical calculations, the body-of-revolution (BOR) technique is utilized. Due to the frequency-dependent ferrite permeability, FEM leads to a nonlinear eigenvalue problem that is challenging to solve. To this end, Beyn’s method is proposed. The effectiveness of the proposed approach is confirmed...
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Błędy projektowe przyczyną stabu awaryjnego żelbetowego zbiornika na koks
PublikacjaW artykule przedstawiono opis uszkodzeń konstrukcji otwartego prostopadłościennego żelbetowego zbiornika który stanowi element ciągu technologicznego produkcji koksu w zakładzie rafineryjnym. Występujące uszkodzenia zbiornika były następstwem istotnego błędu projektowego. W pracy przedstawiono koncepcję naprawy możliwej do przeprowadzenia w trakcie ciągłej pracy instalacji, z podziałem na etapy realizacji.
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The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study
PublikacjaBackground: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). Material and Methods: In CBCTs, the effect of impacted third molars on the root surface of adjacent second...
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Solubility of Methane in Water: Some Useful Results for Hydrate Nucleation
PublikacjaIn this paper, the solubility of methane in water along the 400 bar isobar is determined by computer simulations using the TIP4P/Ice force field for water and a simple LJ model for methane. In particular, the solubility of methane in water when in contact with the gas phase and the solubility of methane in water when in contact with the hydrate has been determined. The solubility of methane in a gas–liquid system decreases as temperature...
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Discussion of Derivability of Local Residual Stress Level from Magnetic Stray Field Measurement
PublikacjaThe NDT procedure dubbed ‘metal magnetic memory’ method and the related ISO 24497 standard has found wide industrial acceptance in some countries, mainly in Russia and China. The method has been claimed by some researchers (Roskosz and Bieniek in NDT&E Int 45:55–62, 2012; Wilson et al. in Sens Actuators A 135:381–387, 2007) as having potential for quantitative determination of local residual stress state in engineering structures,...
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The method of analysis of damage reinforced concrete beams using terrestial laser scanning
PublikacjaThe authors present an analysis of the possibility to assess deformations and mechanisms of destructing bent reinforced concrete beams using the terrestrial laser scanning. As part of the experiments carried out at the Regional Laboratory of Construction of the Concrete Structures Division of the Civil and Environmental Engineering Faculty at Gdansk University of Technology, the reinforced concrete beams were subjected to destruction...
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Earthquake-induced pounding between equal height multi-storey buildings considering soil-structure interaction
PublikacjaThe present paper investigates the coupled effect of the supporting soil flexibility and pounding between neighbouring, insufficiently separated equal height buildings under earthquake excitation. Two adjacent three-storey structures, modelled as inelastic lumped mass systems with different structural characteristics, have been considered in the study. The models have been excited using a suit of ground motions with different peak...
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Evaluation of the stiffness modulus and phase angle of cold in-place recycled mix-tures for long curing periods
PublikacjaArticle presents the changes inbehaviour of cold-in place recycling mixtures made using cement and bituminous emulsion (CIR mixtures) after anelongated time of curing. Most of the available literatureregarding change instiffness modulus and phase angle presents resultsfor a maximum of several dozen days,which makesit difficult to predict the behaviour over the whole life of the compacted layer. The article...
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Rynkowa premia za ryzyko w warunkach polskich
PublikacjaRynkowa premia za ryzyko stanowi niezbędny element dla celów szacowania kosztu kapitału własnego i zarazem stopy dyskontowej. W artykule ukazano zagadnienia dotyczące metod szacowania premii za ryzyko, z uwzględnieniem warunków polskich. Ponadto przeprowadzono kalkulację realnej rynkowej premii za ryzyko dla warunków polskich na podstawie danych pochodzących z rodzimego rynku.
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Multi-level models of transport systems for traffic management
PublikacjaThe region of Pomorskie uses a variety of tools for forecasting and analysing transport. They can be operated, calibrated and updated with data that will be collected and stored in the TRISTAR system. An initiative of the Department of Highway Engineering of the Gdansk University of Technology is designed to develop and implement an integrated and hierarchical system for forecasting and analysing transport called MST (Multilevel...
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Primum non necere, czyli jak uczyć, żeby nie szkodzić
PublikacjaNiezbędna dla projektanta znajomość teorii kompozycji, stylów, kierunków,mód architektonicznych musi stanowić element wspomagający wciąż kształconą i pielęgnowana wrażliwość i umiejętność ekspresyjnego wyrażania emocji, przy użyciu form przestrzennych. Każdy student jest jedynym właścicielem i dysponentem swojej osobowości. To ona określa wrażliwość, ustala granice prywatności, rządzi emocjami i kreuje sposób ekspresji.
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Geometrically nonlinear analysis of shells - Benchmark problems for Autocad Robot Analysis Professional
PublikacjaThe aim of this work is to verify the suitability of commercial engineering software for geometrically nonlinear analysis of shells. This paper deals with the static, geometrically nonlinear analysis of shells made of an isotropic material. The Finite Element Method (FEM) is chosen to solve the problem. The results of the commercial software Autocad Robot Structural Analysis Professional (ARSAP) are compared with the litera-ture...
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Durability evaluation of technical fabrics
PublikacjaA thorough examination of the influence of the conditions of use on the mechanical properties of technical fabrics is proposed. Laboratory experiments (uniaxial tensile, rheological, cyclic and biaxial tensile tests) have been conducted and the material’s parameters for Finite Element Method (FEM) simulations have been identified. Various constitutive models of technical fabrics are investigated and compared. On the basis of these...
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Optimal configuration of an electrode array for measuring ventricles' contraction
PublikacjaAn influence of an electrode-array configuration on an impedance signal composition for a fixed spatial distribution of its sources is examined in the paper. The Finite Element Method and Geselowitz relationship were used for examining three different electrode-arrays. A sensitivity approach was used to evaluate each configuration assuming that localization of the signal source is known. A conductivity change, thus the source of...
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FEM approach to modeling of an irregular trabecular structure
PublikacjaThe aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the...
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Realizacja elementu LMS wspomagającego proces oceny wiedzy uczestników kursu
PublikacjaW rozdziale monografii omówiono mechanizmy realizacji testowania wiedzy studentów w systemach LMS. Przedstawiono opracowany na Wydziale Elektroniki, Telekomunikacji i Informatyki Politechniki Gdańskiej element systemu LMS oceny wiedzy uczestników zajęć laboratoryjnych. Wyróżniającą cechą tego systemu jest jego modułowa, rozproszona i hierarchiczna architektura oraz niezależność od jakości pracy sieci komputerowej.
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A study on transverse shear correction for laminated sandwich panels
PublikacjaThe paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing...
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A new open-source software developed for numerical simulations usingdiscrete modeling methods
PublikacjaThe purpose of this work is to present the development of an open-source software based on a discrete description of matter applied to study the behavior of geomaterials. This software uses Object Oriented Programming techniques, and its methodology design uses three different methods, which are the Discrete Element Method (DEM) [F. Donzé, S.A. Magnier, Formulation of a three-dimensional numerical model of brittle behavior, Geophys....
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Cross-sectional imaging of materials structure using PS-OCT
PublikacjaOptical low-coherence tomography is a measurement technique for non-contact and non-destructive investigation of materials inner structure. Nowadays, this method is highly applied in medical treatment especially in dermatology and ophthalmology. During our research we have developed an optical low-coherence tomography system with polarization state analysis for structure examination of a broad range of technical materials. In this...
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A fair distribution scheme for joint fingerprinting and decryption methods= Sprawiedliwy schemat dystrybucji dla metod łącznego osadzania odcisku palca oraz deszyfracji
PublikacjaThe paper addresses the fairness of the security provided by digital fingerprinting methods. It was noted that the digital fingerprinting techniques are designed primarily to protect service providers against the actions of malicious users, while honest users remain vulnerable to acts of malicious providers. The paper describes the customer's rights problem and the unbinding problem, which also apply to joint fingerprinting and...
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Does the low optical band gap of yellow Bi3YO6 guarantee the photocatalytical activity under visible light illumination?
PublikacjaBi3YO6, which is known as an ionic conductor, was tested here as an electrode and photoanode in contact with aqueous electrolytes. Bi3YO6 was deposited onto the Pt substrate and the such prepared electrode was polarized in various aqueous electrolytes. The optical energy band gap of the material equal to 1.89 eV was determined using the Kubelka-Munk function resulting from the UV-Vis spectrum (allowed indirect transition) and also...
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Analysis of Positioning Error and Its Impact on High Frequency Performance Parameters of Differential Signal Coupler of Differential Signal Coupler
PublikacjaThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring presented in [1, 2]. The theoretical...
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Modification of quaternary structure of Candida albicans GlcN-6-P synthase and its desensitization to inhibition by UDP-GlcNAc by site-directed mutagenesis
PublikacjaSite-directed mutagenesis of the CaGFA1 gene encoding glucosamine-6-phosphate synthase from Candida albicans was performed. Desensitization of the enzyme to inhibition by UDPGlcNAc was achieved upon T487I and H492F substitutions at the UDP-GlcNAc binding site, exchange of D524, S525 and S527 for Ala at the dimer:dimer interface and construction of the tail-lock array (L434R and L460A) at the C-tail region. The first two sets if...
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Surface texture of pine wood beams after planing in industrial conditions
PublikacjaMeasuring the surface features of wooden components after planing is connected with the rising demands regarding to the quality of the painted window frames. In the paper the complex surface texture analysis especially identifying of surface damages using non-contact 3D measurement techniques for precise area measurement were presented.This enabled the study of irregular surface features with sufficient fidelity and resolution....
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Monitoring of occupational exposure to volatile organohalogen solvents (VOXs) in human urine samples of dry-cleaner workers by TLHS-DAI-GC-ECD procedure
PublikacjaChlorinated hydrocarbon solvents are often used for dry-cleaning clothes in the laundry industry. The object of this study was to monitor the occupational exposure of dry-clean employees coming into contact with VOXs. 25 workers collected their urine samples before the work shift, after 4 hours of work and after the work shift. The analyses of urine samples and solvents used in dry-cleaning were performed using TLHS-DAI-GC-ECD....
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The idea of a robotic single-sided lapping system
PublikacjaThis paper reviews the idea of a robotic lapping system. Robot’s assistance automates the lap-ping process and supports the development of a flexible lapping system. However, the main aim behind the idea of a robotic lapping system is to provide improved means for controlling the posi-tion of conditioning rings on a lapping plate. Due to the kinematics of lapping process, the profile wear of the tool is not constant along the radius....
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The study of structure and surface morphology of lithium titanate sol-gel derived thin films
PublikacjaIn this paper the structure and the surface morphology of lithium titanate (LTO) thin films are presented. Nanocrystalline thin films were prepared by sol–gel method. To examine the influence of the annealing time on as-prepared films crystallization, the coatings were heated at different temperatures in the range of 500 °C–600 °C for 10, 20, 40 and 80 h. The structure of the obtained material was investigated using the X-ray diffraction...
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Stirling engines - the state of technology development and computational models
PublikacjaStirling engines represent a technologically important solution in combined heat and power systems. Their use enables the achievement of over 90 percent efficiency in the management of the primary energy source with a very high durability of the device, mainly due to the lack of contact of the working gas with external factors and a very small number of mechanical components. The use of a Stirling engine may be equally important...
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Nano Tin/Tin Oxide Attached onto Graphene Oxide Skeleton as a Fluorine Free Anode Material for Lithium-Ion Batteries
PublikacjaHerein, we show a composite formation method of tin/tin oxide nanoparticles with graphene oxide and CMC based on laser ablation technique as an electrode material for energy storage devices. The material exhibited a three-dimensional conducting graphene oxide network decorated with tin or tin oxide nanoparticles. The structure, homogeneous distribution of nanoparticles, and direct contact between inorganic and organic parts were...