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Gdańsk University of Technology

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  • Human Computer Interface for Tracking Eye Movements Improves Assessment and Diagnosis of Patients With Acquired Brain Injuries
    • Michał Lech
    • Michał Tomasz Kucewicz
    • Andrzej Czyżewski
    2019 Full text Frontiers in Neurology

    One of the first clinical signs differentiating the minimally conscious state from the vegetative state is the presence of smooth pursuit eye movements occurring in direct response to moving salient stimuli. Glasgow Coma Scale (GCS) is one of the most commonly used diagnostic tools for acute phase assessment of the level of consciousness, together with a neurological examination. These classic measures are limited to qualitative neurological examination without more quantitative measures provided from e.g., tasks with tracking position of the gaze. Among this and other limitations, it is prone to a relatively high rate of misdiagnosis. Here, we developed an interface for gaze tracking to enhance the assessment of consciousness in 10 patients with acquired brain injuries. According to the acute phase GCS assessment, nine of them were considered unaware and below the minimally conscious state. Chronic neurological examination confirmed six of them below the minimally conscious state. Our new Human Computer Interface (HCI) revealed that six patients were conscious enough to complete at least one of the gaze tracking tasks. Among these six patients, one was originally diagnosed as remaining in a vegetative state and one in coma. The patient diagnosed as remaining in a chronic vegetative state scored six GCS points acutely. Following assessment with our HCI the patient was re-diagnosed with a possible locked-in syndrome. Our HCI method provides a new complementary tool for clinical assessment of patients suffering from disorders of consciousness.

  • Human verbal memory encoding is hierarchically distributed in a continuous processing stream
    • Michał Tomasz Kucewicz
    • Krishnakant Saboo
    • Brent M. Berry
    • Vaclav Kremen
    • Laura R. Miller
    • Fatemeh Khadjevand
    • Cory S. Inman
    • Paul A. Wanda
    • Michael R. Sperling
    • Richard Gorniak
    • Kathryn A. Davis
    • Barbara C. Jobst
    • Bradley Lega
    • Sameer A. Sheth
    • Daniel S. Rizzuto
    • Ravishankar K Iyer
    • Michael J. Kahana
    • Gregory A. Worrell
    2019 Full text eNeuro

    Processing of memory is supported by coordinated activity in a network of sensory, association, and motor brain regions. It remains a major challenge to determine where memory is encoded for later retrieval. Here we used direct intracranial brain recordings from epilepsy patients performing free recall tasks to determine the temporal pattern and anatomical distribution of verbal memory encoding across the entire human cortex. High gamma frequency activity (65-115 Hz) showed consistent power responses during encoding of subsequently recalled and forgotten words on a subset of electrodes localized in 16 distinct cortical areas activated in the tasks. More of the high gamma power during word encoding, and less power before and after the word presentation, was characteristic of successful recall and observed across multiple brain regions. Latencies of the induced power changes and this subsequent memory effect between the recalled and forgotten words followed an anatomical sequence from visual to prefrontal cortical areas. Finally, the magnitude of the memory effect was unexpectedly found to be the largest in selected brain regions both at the top and at the bottom of the processing stream. These included the language processing areas of the prefrontal cortex and the downstream visual areas at the junction of the occipital and temporal lobes. Our results provide evidence for distributed encoding of verbal memory organized along a hierarchical posterior-to-anterior processing stream.

  • Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
    • Jacek Łubiński
    • Henryk Olszewski
    2019 Full text Polish Maritime Research

    In the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulation and evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modeling and solution rely on finite element methods and cover the simulation of the structure’s properties along with the influence of the marine environment – sea currents, wave and wind loading, as well as the influence of vibrations, buoyancy and accompanying mass of water. Both commercial and open source mathematical modeling software which is available nowadays allows for cost effective and flexible implementation of advanced models for offshore industrial structures with high level of credibility and safety. The models can be built to suit task-specific requirements and evaluated on the basis of the selected criterial system best suited to the needs of the customer. Examples of methodology for environmental and structural model development are presented, along with simulation results covering a wide scope of data, ranging from stress and deformation to resonant characteristics and issues of technological feasibility

  • Hybrid System for a Person Tracking in Harsh Indoor Environments
    • Piotr Rajchowski
    • Krzysztof Cwalina
    • Jarosław Sadowski
    • Jacek Stefański
    2019

    In the article, the prototype of a system for a person tracking in a harsh indoor environment, especially when no other commercially available radiolocalization system can be used, was briefly described. The prototype realizes the data fusion, i.e. combines data from inertial and environmental sensors and radio distance measurements to estimate the position of a moving person. It is worth noting that the concept and practical realization of the system was consulted with Maritime Regional Unit of Polish Border Guard.

  • Hydraulic analysis of causes of washout of Gdynia-Orłowo seashore during the flood in the Kacza river estuary
    • Michał Szydłowski
    2019 Full text Polish Maritime Research

    In July 2016 in the Three-city agglomeration a rainfall episode of over a day duration and 150 mm summary rainfall height, occurred. This situation, extreme as for Polish conditions, caused significant freshets in rivers and streams running into Gdansk Bay, the Baltic Sea, and serving as collectors of rainfall waters for the sea-coast towns. In many areas of the Three-city flood phenomena and overflows took place. The flood also occurred in the catchment area of the Kacza river in Gdynia. The passing of flood water rise caused damage of many infrastructure objects located along the river valley. The estuary section of the river suffered most, especially sea-shore belt together with beach around the estuary which were significantly washed out. In this paper an approach was made to answer to the question on direct causes of the situation which occurred at the estuary of the Kacza river. To this end, there was worked out a hydrodynamic model of the considered section of the river, based on the solving of two-dimensional differential motion equations of free-surface liquid, and simulations of water flow propagation along the river’s valley were performed for a few variants of hydraulic engineering infrastructure of river bed. Numerical hydraulic analysis made it possible to determine a role of the hydraulic engineering objects in forming the flood water rise as well as their impact on location and range of washout zones of sea-shore belt.

  • Hydraulic resistance analyses of selected elements of the prototype Stirling engine
    • Mariusz Furmanek
    • Jacek Kropiwnicki
    2019 Full text Archives of Thermodynamics

    The paper presents the results of simulation tests of hydraulic resistance and temperature distribution of the prototype Stirling alpha engine supplied with waste heat. The following elements were analyzed: heater, regenerator and cooler. The engine uses compressed air as a working gas. Analyses were carried out for three working pressure values and different engine speeds. The work was carried out in order to optimize the configuration of the engine due to the minimization of hydraulic resistance, while maintaining the required thermal capacity of the device. Preliminary tests carried out on the real object allowed to determine boundary and initial conditions for simulation purposes. The simulation assumes that there is no heat exchange between the regenerator and the environment. The solid model used in simulation tests includes the following elements: supply channel, heater, regenerator, cooler, discharge channel. Due to the symmetrical structure of the analyzed elements, simulation tests were carried out using 1/6 of the volume of the system.

  • Hydro Power Plant in the Process of Voltage Control in the Electric Power System and the System Restoration
    • Zbigniew Lubośny
    • Maciej Łosiński
    2019 Full text Acta Energetica

    The article covers selected issues related to the share of hydroelectric power in the process of rebuilding the power system after black-out and voltage control during that process. Selected results of measurements made during the creation of the transmission chain for the need to start a block of a thermal power plant from a hydroelectric power plant were presented.

  • Hydromechaniczne aspekty projektowania statków z napędem azymutalnym
    • Maciej Reichel
    2019

    W monografii przedstawiono ocenę stanu dotychczasowej wiedzy dotyczącej hydromechanicznych aspektów projektowania statków z pędnikami azymutalnymi, dostępnej w światowym otwartym obiegu wiedzy. Praca prezentuje proces projektowania, w tym optymalizacji kształtu kadłuba statku z napędem azymutalnym. Omówiono wpływ zmian kształtu kadłuba na właściwości manewrowe statków z takim typem napędu, ze szczególnym uwzględnieniem stateczności kursowej. Głównym jednak elementem pracy są te etapy spirali projektowej, które wprost są związane z zagadnieniami hydromechaniki. Monografia zawiera opis procesu optymalizacji właściwości napędowych i manewrowych statków z pędnikami azymutalnymi wraz z szerokim opisem prób modelowych służących optymalizacji. Osobny rozdział poświęcono charakterystykom hydrodynamicznym pędników azymutalnych w warunkach wody otwartej. Zwrócono uwagę na odmienne znaczenie sił napędowych i sił sterujących generowanych na pędnikach azymutalnych w procesie projektowania. Monografia zawiera najnowsze informacje dotyczące projektowania statków oraz pędników azymutalnych, dostępne w światowej literaturze. Uwzględnia ona zarówno prace badawcze wykonywane przez międzynarodowe środowisko hydromechaników, jak i prace autora realizowane przez wiele lat w polskich i zagranicznych ośrodkach naukowych. W podsumowaniu monografii zaprezentowano krytyczną ocenę procedur badania i projektowania statków z pędnikami azymutalnymi oraz przyszłe tematy badawcze, które według autora powinny zostać podjęte w najbliższym czasie w celu podniesienia jakości procesu projektowania.

  • Hydrothermal synthesis of vanadium ammonium compounds – the crucial role of the pressure
    • Małgorzata Nadolska
    • Marta Prześniak-Welenc
    • Andrzej Nowak
    • Kamila Sadowska
    2019

    Due to the structural diversity and chemical activity, vanadium oxides and their derivatives are continuingly in the great interest of scientist. In a large family of vanadium compounds, one of the most interesting are ammonium vanadates (with the general formula (NH4)xVyOz). They have received much attention because of their promising application as cathode material in mono- and multivalent-ion batteries [1]. Hydrothermal synthesis is already established as an efficient method to produce ammonium vanadates with various morphology, structure and chemical composition. The aforementioned parameters determined the electrochemical properties of the material and could be tailored by varying synthesis parameters (e.g. temperature, time, pH) [2]. In presented work, the effect of the initial hydrothermal synthesis pressure on the final product was studied for the first time. All samples were prepared via hydrothermal method in the autoclave, in which the water solution of NH4VO3 and C2H2O4 was heated to 180°C for 8h. In order to study the pressure effect, the same procedure was repeated without the initial pressure and with pre-pressurized the autoclave to 5, 25, 50 bars. The obtained samples were fully characterized with SEM, TEM, XRD, XPS, FTIR and TGA. Results indicate that the initial pressure affects both the morphology and the structure of samples and cannot be neglected in the synthesis. Moreover, the electrochemical performance of the as-prepared samples as lithium-ion cathode materials were investigated. It was found that sample obtained with higher pressure exhibit higher specific capacity and cyclic stability. FIGURE 1. Comparison of ammonium vanadates obtained with different initial hydrothermal synthesis pressure. Acknowledgements Part of this work was supported by the National Science Centre (No. 2017/01/X/ST5/01415). References [1] Y. Liu et al.J., Mater. Sci., 53(3),pp. 2045–2053, 2018 [2] S. Sarkar et al., Electrochim. Acta, vol. 132, pp. 448–456, 2014.

  • Hyperbolic heat conduction at a microscopic sliding contact with account of adhesion-deformational heat generation and wear
    • Oleksii Nosko
    2019 Full text INTERNATIONAL JOURNAL OF THERMAL SCIENCES

    Different non-Fourier models were proposed to simulate temperatures in materials subjected to extremely fast thermal disturbances, when the speed of heat propagation should be concerned. The present study investigated temperature and heat balance at a microscopic sliding contact during a single frictional interaction based on the Cattaneo-Vernotte hyperbolic heat conduction equation. Two fundamental features of friction, namely, adhesion-deformational heat generation and wear, were taken into account. By applying the Laplace transform approach, non-stationary temperature expressions were derived for the hyperbolic and classical parabolic heat conduction equations. Parametric analysis was then done for parameter ranges typical of brake materials. It was found that the hyperbolic heat conduction generally results in a higher temperature at the sliding surface compared to the parabolic heat conduction. The influence of the heat propagation speed can be significant for thermal relaxation time of the order above microsecond. It becomes stronger with an increase in the contribution of the adhesive heat generation. Another finding obtained is that a considerable fraction of heat is removed from the contact zone along with wear debris, resulting in a lower temperature. This fraction is larger for the hyperbolic heat conduction.

  • ICT-driven economic and financial development. Analyses of European countries
    • Ewa Lechman
    • Adam Marszk
    2019

    ICT-Driven Economic and Financial Development: Analyses of European Countries demonstrates the effects of ICT diffusion on economic, social and financial development by examining their impact on the structure and dynamics of national economies. It provides the insight into shifts observed in labour markets, international trade activities productivity factors, education and use of innovative financial products. It combines empirical analyses and data sources stretching back to 1990 make it an important contribution to understanding the effects of ICT diffusion on economic and financial development. The book answers questions such as how will national and regional economies react to upcoming ICT developments and growing usage, and what is the magnitude of impact of new information and communication technologies on various aspects of social and economic life.

  • Identification, Assessment and Automated Classification of Requirements Engineering Techniques
    • Aleksander Jarzębowicz
    • Kacper Sztramski
    2019 Full text

    Selection of suitable techniques to be used in requirements engineering or business analysis activities is not easy, especially considering the large number of new proposals that emerged in recent years. This paper provides a summary of techniques recommended by major sources recognized by the industry. A universal attribute structure for the description of techniques is proposed and used to describe 33 techniques most frequently quoted by reviewed sources. A pilot study of automated classification of techniques based on attribute values is also reported. The study used fuzzy c-means clustering algorithm and produced pairings of complementary techniques, most of which successfully passed validation conducted by business analysis practitioners.

  • Identification of damages in the inlet air duct of a diesel engine based on exhaust gas temperature measurements
    • Patrycja Puzdrowska
    2019 Full text Combustion Engines

    The temperature of the exhaust gas of a diesel piston engine, measured in the characteristic control sections of its thermo-flow system, can be a valuable source of diagnostic information about the technical condition of the elements limiting the working spaces thus separated, including the turbocharging system, but also its fuel supply system and replacement of the medium. In standard marine engine measurement systems equipped with an impulse turbocharging system, the exhaust gas temperature is measured at the outlet of individual cylinders and before and after the turbocharger turbine, using traditional thermocouples with high measurement inertia (time constant of tenths of a second and more). This means that for further diagnostic analyses, the average value of the periodically changing temperature of the exhaust stream leaving individual engine cylinders, the exhaust stream in the collective duct feeding the turbine and the exhaust stream in the exhaust duct of the turbine is used. This article proposes a new approach to the issue of diagnostic informationiveness of the exhaust gas temperature of a diesel engine, extending its observations with the dynamics of changes in the duration of one working cycle. The aim of the tests carried out on the laboratory stand of Farymann Diesel engine type D10 was to determine the diagnostic relations between the loss of permeability of the inlet air channel filter baffle and selected standards of the quick-changing signal of the exhaust gas temperature. On the basis of the calculations carried out, the following dynamic features of the recorded signal were determined: maximum amplitude of instantaneous exhaust gas temperature values (peak-to-peak value), its rate of increase and decrease, and the specific enthalpy of exhaust gases within one engine work cycle. Comparative analysis of numerical data characterizing the recorded quick-changing exhaust gas temperature courses clearly indicates obvious thermodynamic and energy consequences of partial loss of flow capacity of the air channel supplying the combustion chamber of the test engine. A further development of the experimental test programme is foreseen in order to determine a diagnostic matrix to support the diagnostic inference about the technical condition of the diesel engine on the basis of measurements and analysis of the quick-changing exhaust gas temperature.

  • Identification of evolutionary conserved DNA sequence and corresponding S21 ribosomal protein region for diagnostic purposes of all Borrelia spirochetes
    • Roman Kotłowski
    • Lucyna Holec-Gąsior
    2019 Full text Acta Biochimica Polonica

    It is still under investigation, whether all Borrelia sp. causing Lyme borreliosis and other diseases are already identified and properly classified as human pathogens. For this reason, it is of great importance to develop a diagnostic ELISA test that detects all Borrelia sp. The aim of this study was to identify conserved DNA and protein regions present in all currently known Borrelia sp. In experimental studies 31 available Borrelia sp. genomes were aligned and screened for the presence of evolutionary conserved regions. As a result of bioinformatics analysis, one evolutionally conserved DNA region encoding a core fragment of the S21 ribosomal protein was identified. Both a couple of genus-specific PCR primers and the S21 protein B-cell epitope were designed for prospective diagnostic purposes.

  • Identification of Shear Modulus Parameters of Half-space Inhomogeneous by Depth
    • Vladimir Zelentsov
    • Polina Lapina
    • Victor Eremeev
    2019 Full text AIP Conference Proceedings

    The paper propose a method for determining of the parameters of the exponential shear modulus of a functionally graded half-space based on the solution of the problem of a pure shear of an elastic functionally graded half-space by a strip punch. The solution of the integral equation of the contact problem is constructed by asymptotic methods with respect to the dimensionless parameter. The dependence of contact stresses on the parameters of the shear modulus is analyzed. The determination of the parameters of the shear modulus of a functionally graded half-space is based on the values of shear stresses at the contact. By choosing proper shear modulus parameters of the functionally graded half-space, “approximately homogeneous” area inside of the functionally graded half-space are developed.

  • Identifying Selected Tram Transport Risks
    • Marcin Budzyński
    • Agnieszka Tubis
    • Kazimierz Jamroz
    2019 Full text IOP Conference Series: Materials Science and Engineering

    In the area of transport infrastructure risks, infrastructure is inspected for safety. It is an element of transport safety management based on risk management and forms part of preventative activities and measures. As regards tram infrastructure which is a component of urban transport infrastructure, there are potential collisions with cars, cyclists and pedestrians. Data from Gdansk Buses and Trams (GAiT) shows that between 2012 and 2016 on average there were about 650 incidents involving trams (collisions and accidents). The objective of inspection will be to identify sources of hazards which may lead to tram accidents or indirectly when tram infrastructuremay contribute to accidents not involving trams. The objective of the work is to identify the risks to urban public transport operation with a special focus on trams and to formulate recommendations on how to improve its quality and safety

  • Identyfikacja wad powierzchni tocznej szyn za pomocą sygnału wibroakustycznego
    • Roksana Licow
    • Franciszek Tomaszewski
    2019 Full text Problemy Kolejnictwa

    W artykule przedstawiono koncepcję metody identyfikacji najczęściej występujących wad powierzchni tocznej szyn za pomocą sygnałów wibroakustycznych. Opisano badane wady szyn take, jak: squat, head checking oraz wybuksowanie. Przedstawiono metodykę prowadzonych badań oraz wyniki analiz zarejestrowanych sygnałów dla warunków techniczno-eksploatacyjnych panujących na liniach kolejowych nr 213 Reda – Hel oraz nr 131 Chorzów Batory – Tczew. Wyniki badań drgań i hałasu dotyczą zarejestrowanych sygnałów dla odcinków toru z wadą oraz dla odcinków toru referencyjnego. Synteza wyników badań potwierdza zasadność rozwijania metody z wykorzystaniem sygnałów drganiowych do prowadzenia diagnostyki powierzchni tocznych szyn, jak również wskazuje na możliwość wykorzystania sygnałów wibroakustycznych do oceny innych elementów nawierzchni kolejowej.

  • Impact of Boundary Conditions on Acoustic Excitation of EntropyPerturbations in a Bounded Volume of Newtonian Gas
    • Anna Perelomova
    2019 Full text Archives of Acoustics

    Excitation of the entropy mode in the field of intense sound, that is, acoustic heating, is theoreticallyconsidered in this work. The dynamic equation for an excess density which specifies the entropy mode,has been obtained by means of the method of projections. It takes the form of the diffusion equation withan acoustic driving force which is quadratically nonlinear in the leading order. The diffusion coefficient isproportional to the thermal conduction, and the acoustic force is proportional to the total attenuation.Theoretical description of instantaneous heating allows to take into account aperiodic and impulsivesounds. Acoustic heating in a half-space and in a planar resonator is discussed. The aim of this studyis to evaluate acoustic heating and determine the contribution of thermal conduction and mechanicalviscosity in different boundary problems. The conclusions are drawn for the Dirichlet and Neumannboundary conditions. The instantaneous dynamic equation for variations in temperature, which specifiesthe entropy mode, is solved analytically for some types of acoustic exciters. The results show variationin temperature as a function of time and distance from the boundary for different boundary conditions.Keywords:nonlinear acoustics; acoustic heating in resonators; Burgers equation; first and second typeboundary conditions; acoustic heating in a half-space

  • Impact of Cyclist Facility Availability at Work on the Number of Bike Commuters
    • Romanika Okraszewska
    2019 Advances in Intelligent Systems and Computing

    The article describes the results of research designed to establish whether cycle provision can influence the number of employees commuting by bike. To that end, employee surveys were conducted in three IT companies in 2012 and 2016. The questionnaire asked about travel behaviour and what the staff thought about their company’s provision of cyclist facilities. Since 2012 each of the companies has moved its head office and the facilities for cyclists have improved. The studies from 2012 indicated a greater impact of an unseen level of organizational culture than that of artifacts such as facilities for cyclists at the company or its location relative to the system of city cycle paths. Results from 2016 indicate that when significant changes are made on the artifacts level the influence on the number of cyclists can be noticeable.

  • Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
    • Leszek Jarzębowicz
    • Miroslav Gutten
    2019 Full text

    In applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified as a source of errors in determining motor current feedback using the typical technique dedicated for microprocessor-based controllers. First, sampling the phase currents synchronously with the peaks of modulation carrier provides results of mean currents under an assumption of linear current changes in steady voltage intervals. This assumption is over-simplistic in high-speed drives. Second, transforming the phase currents into a rotating reference frame, required in Field Oriented Control (FOC), is carried out using discretized rotor angle. If rotor covers a substantial angular distance in the control cycle, such simplification distorts transformation results considered as mean values. This paper analyses the joint impact of both these oversimplifications on the errors of field-oriented current components derived in a microprocessor as a feedback to the control algorithm. The analysis was carried out for a high-speed PMSM drive operating at switching frequency of 5 kHz and maximal fundamental frequency of 350 Hz. Simulation results show that the considered oversimplifications lead to notable errors in digital processing of current feedback. The direct-axis current is affected by a notable offset, while the quadrature-axis current is supplemented with a high-frequency error component.

  • Impact of high temperature drying process on beech wood containing tension wood
    • Ivan Klement
    • Tatiana Vilkovská
    • Uhrín Miroslav
    • Jacek Barański
    • Aleksandra Konopka
    2019 Full text Open Engineering

    The technology of high temperature drying has a great inuence on dimensional and selected physical changes in tension wood. Article is focused on the measurement properties such as moisture content, color changes and longitudinal warping. The quality of beech wood is determined based on structure and properties of wood, frequency of defects in wood material. The tension wood is considered as an important wood defect causing negative alterations in solidwood quality and limits industrial application ofwood. The dierent values of longitudinalwarpingwhichwere measured after dryingwere higher in tensionwood than in normalwood. Impact of radial and tangential angle of growth rings is non-signicant factor.

  • Impact of polder flood plain of the Cisowska Struga on the transformation of flood waves between Gdynia and Rumia
    • Michał Szydłowski
    • Wojciech Szpakowski
    2019 Full text Acta Scientiarum Polonorum Formatio Circumiectus

    The paper presents the results of hydraulic calculations (numerical simulations), which were made to investigate the role of floodplain (polder) adjacent to the left bank of Cisowska Struga in Gdynia downstream Hutnicza St. in the process of retention and transformation of flood waves occurring in this river due to torrential rainfall. The paper also addressed the issue of the impact of potential changes in the development of the retention area under consideration for the flood risk in Rumia.

  • Impact of probability distribution on the uncertainty of resistance measurement
    • Stanisław Szczesny
    • Anna Golijanek-Jędrzejczyk
    • Dariusz Świsulski
    2019 Full text ITM Web of Conferences

    The paper presents studies on the influence of probability distributions on the expanded uncertainty of the resistance measurement. Choosing the correct probability distribution is very important to estimate of measurement uncertainty. The paper presents the results of analysis of the resistance measurement uncertainty using the technical method of resistance: 100 G. The analysis of the uncertainty measurement of resistance was carried out repeatedly, each time assuming a different probability distribution of measuring instruments (normal, quadratic, U and triangular distribution).The results of the research presented in the article show that the influence of the assumed probability distributions on the result of the measurement uncertainty analysis is significant and results discrepancies can reach up to 40%.

  • Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
    • Mariusz Jaczewski
    • Bohdan Dołżycki
    • Jacek Alenowicz
    • Piotr Jaskuła
    2019 Full text Roads and Bridges - Drogi i Mosty

    Hot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point bending test. Mixtures differed in: type (for wearing, binder or base courses), content of RAP (from 0% up to 60%), quality of RAP material and application of rejuvenator. For all mixtures, RAP content strongly influences mechanical properties – critical strain and flexural strength. Their values decreased with an increase in the used amount of RAP. The greatest decrease was observed for wearing and binder courses. The changes were much smaller for base course mixtures, even with higher amounts of RAP.

  • Impact of slow breathing on the blood pressure and subarachnoid space width oscillations in humans
    • Magdalena Nuckowska
    • Marcin Gruszecki
    • Jacek Kot
    • Jacek Wolf
    • Wojciech Gumiński
    • Andrzej F. Frydrychowski
    • Jerzy Wtorek
    • Krzysztof Narkiewicz
    • Krzysztof Narkiewicz
    • Pawel Winklewski
    2019 Full text Scientific Reports

    The aim of the study was to assess cardiac and respiratory blood pressure (BP) and subarachnoid space (SAS) width oscillations during the resting state for slow and fast breathing and breathing against inspiratory resistance. Experiments were performed on a group of 20 healthy volunteers (8 males and 12 females; age 25.3 ± 7.9 years; BMI = 22.1 ± 3.2 kg/m2). BP and heart rate (HR) were measured using continuous finger-pulse photoplethysmography. SAS signals were recorded using an SAS monitor. Oxyhaemoglobin saturation (SaO2) and end-tidal CO2 (EtCO2) were measured using a medical monitoring system. Procedure 1 consisted of breathing spontaneously and at controlled rates of 6 breaths/minute and 6 breaths/minute with inspiratory resistance for 10 minutes. Procedure 2 consisted of breathing spontaneously and at controlled rates of 6, 12 and 18 breaths/minute for 5 minutes. Wavelet analysis with the Morlet mother wavelet was applied for delineation of BP and SAS signals cardiac and respiratory components. Slow breathing diminishes amplitude of cardiac BP and SAS oscillations. The overall increase in BP and SAS oscillations during slow breathing is driven by the respiratory component. Drop in cardiac component of BP amplitude evoked by slow-breathing may be perceived as a cardiovascular protective mechanism to avoid target organ damage. Further studies are warranted to assess long-term effects of slow breathing.

  • Impact of Tetrazolium Ionic Liquid Thermal Decomposition in Solvothermal Reaction on the Remarkable Photocatalytic Properties of TiO2 Particles
    • Marta Paszkiewicz-Gawron
    • Anna Gołąbiewska
    • Anna Pancielejko
    • Wojciech Lisowski
    • Julia Zwara
    • Monika Paszkiewicz
    • Adriana Zaleska-Medynska
    • Justyna Łuczak
    2019 Full text Nanomaterials

    Ionic liquids (ILs) could serve as a structuring agent, a solvent, or a source of dopant during solvothermal synthesis of semiconductors particles. To understand the role of IL during formation of TiO2 particles, it is necessary to study the stability of this IL in solvothermal synthesis conditions, as well as studying the surface properties of formed TiO2 particles. In view of this, the effect of the 2,3,5-triphenyltetrazolium chloride IL ([TPTZ][Cl]) thermal decomposition during the solvothermal reaction and IL content in the reaction system on photoactivity of TiO2 microparticles has been systematically investigated. The samples obtained by using [TPTZ][Cl] exhibited remarkable photocatalytic properties in phenol degradation reaction under visible light. HPLC analysis of the solvothermal reaction medium and X-ray photoelectron spectroscopy (XPS) analysis of TiO2 particles revealed that [TPTZ][Cl] was decomposed completely and was incorporated into the TiO2 lattice. Generally, increasing the reaction time (1, 4, 12, and 24 h) promoted the TiO2 microspheres formation, as well as raising the visible light-induced photocatalytic activity of the photocatalysts. Longer reaction time was also accompanied by an increase in the efficiency of 2,3,5-triphenyltetrazolium chloride decomposition. The properties of the photocatalysts were investigated by means of UV-VIS diffuse reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), X-ray powder diffraction (XRD) analysis, and XPS.

  • Impact of the Artificial Strait in the Vistula Spit on the Hydrodynamics of the Vistula Lagoon (Baltic Sea)
    • Michał Szydłowski
    • Tomasz Kolerski
    • Piotr Zima
    2019 Full text Water

    In the Vistula Lagoon, storm surges are induced by variable sea levels in the Gulf of Gdańsk and wind action. The rising of the water level in the southern part of the basin, exceeding 1.0 m above mean sea level, can be dangerous for the lowland area of Żuławy Elbląskie, causing the inundation of the polders adjacent to the lagoon. One of the potential possibilities to limit the flood risk is to decrease the water level in the lagoon during strong storm surges by opening an artificial canal to join the lagoon with the Gulf of Gdańsk. The decision to build a new strait in the Vistula Spit was made in 2017. In order to analyze the impact of the artificial connection between the sea and the lagoon during periods of high water stages in the southern part the lagoon, mathematical modelling of the hydrodynamics of the Vistula Lagoon is required. This paper presents the shallow water equations (SWEs) model adapted to simulate storm surges driven by the wind and sea tides, and the numerical results obtained for the present (without the new strait) and future (with the new strait) configuration of the Vistula Lagoon.

  • IMPACT OF THE ORGANISATION OF MEGA SPORTING EVENTS ON SELECTED ELEMENTS OF THE TOURISM SECTOR
    • Krystian Zawadzki
    2019 Full text Polish Journal of Sport and Tourism

    Introduction. In the world-wide literature, there is no unanimity in the assessment of the impact of mega sporting events on the tourism sector. Therefore, the main purpose of this study was to quantify the impact of mega sporting events on changes in tourist inflow and the amount of expenditure incurred by visitors. Material and methods. In this study, an ex-post analysis of many different categories of mega sporting events was carried out in the context of their impact on selected aspects of the tourism sector in host countries. The study examined events organised in the years 1996-2014 classified into one of four categories: the Summer Olympic Games (SOG), the Winter Olympic Games (WOG), the Football World Cup (FIFA), and the European Football Championship (UEFA). The approach adopted made it possible to analyse the impact of sporting events on the tourism sector over 15 years. Data on both the inflow of tourists and the expenditure generated by them were taken from a single source – reports of the United Nations World Tourism Organization (UNWTO). Results. The results obtained are characterised by ambiguity, although the study identified the categories of sporting events and the sporting event phase in which clearly positive or negative effects on the tourism sector could be observed. Conclusions. The difficulty in confirming unambiguously positive, tangible effects on the tourism sector resulting from the organisation of mega sporting events makes it problematic to justify the commitment of large expenditure to preparing and conducting these events. It is necessary to look for other, intangible benefits related to the organisation of these events. It also seems appropriate to continue the research undertaken in the future on the basis of data disaggregated at the regional level.

  • Implementation of Addition and Subtraction Operations in Multiple Precision Arithmetic
    • Kamil Rudnicki
    • Tomasz Stefański
    2019

    In this paper, we present a digital circuit of arithmetic unit implementing addition and subtraction operations in multiple-precision arithmetic (MPA). This adder-subtractor unit is a part of MPA coprocessor supporting and offloading the central processing unit (CPU) in computations requiring precision higher than 32/64 bits. Although addition and subtraction operations of two n-digit numbers require O(n) operations, the efficient implementation of these operations can provide valuable time-savings for the MPA coprocessor. Furthermore, MPA numbers are usually stored with the use of the sign-magnitude representation which is not so straightforward for addition/subtraction implementation as the two's complement representation. Our adder-subtractor unit is implemented using the very high speed integrated circuit hardware description language (VHDL) and benchmarked on Xilinx Artix-7 FPGA. The developed digital circuit of the MPA adder-subtractor works with integer numbers of precision varying in the range between 64 bits and 32 kbits with the limb size set to 64 bits. It can currently work with the clock frequency exceeding 450 MHz. For the developed implementation, the addition of two k-limb numbers takes 33+k clock cycles. Hence, the developed coprocessor is 1.7 times faster than a single core of modern i7 processor for precision set to 32704 bits.

  • Implementation of control system and tracking objects in a Quadcopter
    • Siva Ariram
    • Juha Roning
    • Zdzisław Kowalczuk
    2019 Full text

    In this paper, we implement a quadcopter assembly with control and navigation module. The project also includes the design of the control panel for the operator which consists of a set of the micro-controller and the glove equipped with sensors and buttons. The panel has a touch screen which displays current parameters such as vehicle status, including information about orientation and geographical coordinates. The concept of quadcopter control is based on the movement of the operator hand. In addition, we have included the object detection for detecting the objects from the quadcopter view of point. To detect an object, we need to have some idea of where the object may be and how the image is divided into segments. It creates a kind of chicken and egg problem, where we must recognize the shape (and class) of the object knowing its location and recognize the location of the object knowing its shape. Some visual characteristics such as clothing and the human face, they can be part of the same subject, but it is difficult to recognize this without recognizing the object first.

  • Implementing Smart Virtual Product Development (SVPD) to Support Product Manufacturing
    • Muhammad Ahmed
    • Cesar Sanin
    • Edward Szczerbicki
    2019

    This paper illustrates the concept of providing the manufacturing knowledge during early stages of product life cycle to experts working on product development. The aim of this research is to enable a more collaborative product development environment by using Smart Virtual Product Development (SVPD) system, which is powered by Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). It enhances the industrial product development process by storing, using and sharing previous manufacturing experience and knowledge. This knowledge is stored in form of formal decisional events after being collected from the set of similar products having some common functions and features. The proposed system uses a collective, team-like knowledge developed by product designers, manufactures, and metrologists. Implementing this system in the process of product development enables the small and medium enterprises (SMEs) to take proper decisions at appropriate time by reducing mistakes at an early stages of product development.

  • Importance of Specific Heat Characterization when Reporting New Superconductors: An Example of Superconductivity in LiGa2Rh
    • Elizabeth M. Carnicom
    • Weiwei Xie
    • Zoe Yang
    • Karolina Górnicka
    • Tai Kong
    • Tomasz Klimczuk
    • Robert J. Cava
    2019 CHEMISTRY OF MATERIALS

    We show that the full-Heusler compound LiGa2Rh is a superconductor with Tc = 2.4 K. The new superconductor was found as a result of an intuition-based extension of a database search for superconductors that looked for the presence of peaks in the electronic band structure near the Fermi energy. The measurement of the entropy loss during the transition from the nonsuperconducting to the superconducting state, a straightforward measurement rarely presented in reports of “new” superconducting materials, played a critical role in identifying and isolating the superconducting compound. This study presents a particularly good example of how specific heat measurements are important for the identification and isolation of a new superconductor, since much more frequently reported resistive and magnetic susceptibility characterizations are often not enough to confirm the identification of a new superconducting material.

  • Improved Empirical Coefficients for Estimating Water Vapor Weighted Mean Temperature over Europe for GNSS Applications
    • Zofia Baldysz
    • Grzegorz Nykiel
    2019 Full text Remote Sensing

    Development of the so-called global navigation satellite system (GNSS) meteorology is based on the possibility of determining a precipitable water vapor (PWV) from a GNSS zenith wet delay (ZWD). Conversion of ZWD to the PWV requires application of water vapor weighted mean temperature (Tm) measurements, which can be done using a surface temperature (Ts) and its linear dependency to the Tm. In this study we analyzed up to 24 years (1994–2018) of data from 49 radio-sounding (RS) stations over Europe to determine reliable coefficients of the Tm-Ts relationship. Their accuracy was verified using 109 RS stations. The analysis showed that for most of the stations, there are visible differences between coefficients estimated for the time of day and night. Consequently, the ETm4 model containing coefficients determined four times a day is presented. For hours other than the primary synoptic hours, linear interpolation was used. However, since this approach was not enough in some cases, we applied the dependence of Tm-Ts coefficients on the time of day using a polynomial (ETmPoly model). This resulted in accuracy at the level of 2.8 ± 0.3 K. We also conducted an analysis of the impact of this model on the PWV GNSS. Analysis showed that differences in PWV reached 0.8 mm compared to other commonly used models.

  • Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
    • Marek Krzaczek
    • Jarosław Florczuk
    • Andrzej Tejchman-Konarzewski
    2019 APPLIED ENERGY

    Effective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat supply into and heat extraction from external walls containing embedded pipes. The installed pipe-embedded wall heating/cooling system is fully controlled by a special fuzzy logic program that synchronizes the heat supply/extraction with variable heat loads. The main operation rule of the Thermal Barrier is to keep changes of the wall internal energy close to zero for the given reference temperature of a pseudo-surface created by an embedded pipe system of the wall heat exchanger. Comprehensive field measurement results associated with an example Thermal Barrier System installed in a residential two-story house are presented. These measurements confirmed the high-efficiency of the Thermal Barrier and its ability to use low-grade heat sources and sinks to effectively control an indoor climate. The supply water temperature was very low (25.3 °C) in the winter and very high (20.5 °C) in the summer. Daily variations of the indoor air temperature did not exceed 0.8 °C throughout the year. During the summer, the Thermal Barrier System operated in cooling-mode only from a low-grade renewable heat sink. The flexibility of the Thermal Barrier also allows for using heat sources/sinks different from those in the test house.

  • Improved RSS-Based DoA Estimation Accuracy in Low-Profile ESPAR Antenna Using SVM Approach
    • Michał Tarkowski
    • Mateusz Burtowy
    • Mateusz Rzymowski
    • Krzysztof Nyka
    • Mateusz Groth
    • Łukasz Kulas
    2019 Full text

    In this paper, we have shown how the overall performance of direction-of-arrival (DoA) estimation using lowprofile electronically steerable parasitic array radiator (ESPAR) antenna, which has been proposed for Internet of Things (IoT) applications, can significantly be improved when support vector machine (SVM) approach is applied. Because the SVM-based DoA estimation method used herein relies solely on received signal strength (RSS) values recorded at the antenna output port for different directional radiation patterns produced by the antenna steering circuit, the algorithm is wellsuited for IoT nodes based on inexpensive radio transceivers. Measurement results indicate that, although the antenna can provide 8 unique main beam directions, SVM-based DoA of unknown incoming signals can successfully be estimated with good accuracy in a fast way using limited number of radiation patterns. Consequently, such an approach can be used in efficient location-based security methods in Industrial Internet of Things (IIoT) applications.

  • Improvement of ships seakeeping performance by application of the Full-scale CFD simulations – case study
    • Karol Niklas
    • Hanna Pruszko
    2019

    The ship’s fuel economy is increasingly important. The paper presents the effect of redesigning a case study ship for increasing seakeeping performance. Selected wave parameters reflects very difficult operational con-ditions existing on the North Sea and the Baltic Sea. The analyzed variants of a case study ship represent the latest developments of modern hull forms. The concepts similar to V-shaped bulbous bow, X-bow, X-aft, B-bow were adopted. Full-scale CFD simulations were performed to analyze the influence of innovative hull forms on the added resistance, heave and pitch motions for head waves and two vessel speeds. It was found that with the use of Full-scale CFD simulations it is possible to capture phenomena that cause ship’s non-linear behavior. The calculated relation between added resistance and ships’ vertical motions was opposite to linear strip theory. It proves that the results obtained by linear strip theory method and the CFD can differ signifi-cantly.

  • Improvement of the load capacity of the road overpass as a result of repairs after breakage caused by vehicle impacts
    • Mikołaj Miśkiewicz
    • Dawid Bruski
    • Jacek Chróścielewski
    • Krzysztof Wilde
    2019 Full text MATEC Web of Conferences

    Damage of spans of the overpass caused by impact of underpassing vehicles are a frequent case. Objects that use prefabricated load-bearing elements that are not designed for such impacts are particularly exposed. After impact, such parts suffer extensive damage that need repair. Taking advantages of this recovery actions it is worth to perform strengthening that will protect object against possible future impacts. In this study the influence of the structural strengthening of the damaged overpass on its strength parameters is investigated. For this purpose the advanced computational model was created. The model includes reinforcement and prestressing tendons. This model enables reliably restore damage caused due to the vehicle's impact and analysing of re-impact the strengthened structure. The damage of the concrete and deformation of the reinforcement is presented.

  • Improvements to the two-phase sandwich method for calculating the melting points of pure metals
    • Kamil Rybacki
    • Valeriy Plechystyy
    • Szymon Winczewski
    • Jarosław Rybicki
    2019 Full text Computational Methods in Science and Technology

    The thermophysical properties of metal alloys are often investigated via molecular dynamics (MD) simulations.An exact and reliable estimation of the thermophysical parameters from the MD data requires a properly and carefullyelaborated methodology. In this paper, an improved two-phase sandwich method for the determination of the metal meltingtemperature is proposed, based on the solid-liquid equilibrium theory. The new method was successfully implemented usingthe LAMMPS software and the C++11 Standard Libraries and then applied to aluminum and copper systems. The resultsshow that the proposed procedure allows more precise calculations of the melting temperature than the widely used one-phase boundary methods.

  • Improving Accuracy of Contactless Respiratory Rate Estimation by Enhancing Thermal Sequences with Deep Neural Networks
    • Alicja Kwaśniewska
    • Jacek Rumiński
    • Maciej Szankin
    2019 Full text Applied Sciences-Basel

    Estimation of vital signs using image processing techniques have already been proved to have a potential for supporting remote medical diagnostics and replacing traditional measurements that usually require special hardware and electrodes placed on a body. In this paper, we further extend studies on contactless Respiratory Rate (RR) estimation from extremely low resolution thermal imagery by enhancing acquired sequences using Deep Neural Networks (DNN). To perform extensive benchmark evaluation, we acquired two thermal datasets using FLIR® cameras with a spatial resolution of 80 × 60 and 320 × 240 from 71 volunteers in total. In-depth analysis of the proposed Convolutional-based Super Resolution model showed that for images downscaled with a factor of 2 and then super-resolved using Deep Learning (DL) can lead to better RR estimation accuracy than from original high-resolution sequences. In addition, if an estimator based on a dominating peak in the frequency domain is used, SR can outperform original data for a down-scale factor of 4 and images as small as 20 × 15 pixels. Our study also showed that RR estimation accuracy is better for super-resolved data than for images with color changes magnified using algorithms previously applied in the literature for enhancing vital signs patterns.

  • Improving SBR Performance Alongside with Cost Reduction through Optimizing Biological Processes and Dissolved Oxygen Concentration Trajectory
    • Robert Piotrowski
    • Aleksander Paul
    • Mateusz Lewandowski
    2019 Full text Applied Sciences-Basel

    Authors of this paper take under investigation the optimization of biological processes during the wastewater treatment in sequencing batch reactor (SBR) plant. A designed optimizing supervisory controller generates the dissolved oxygen (DO) trajectory for the lower level parts of the hierarchical control system. Proper adjustment of this element has an essential impact on the efficiency of the wastewater treatment process as well as on the costs generated by the plant, especially by the aeration system. The main goal of the presented solution is to reduce the plant energy consumption and to maintain the quality of effluent in compliance with the water-law permit. Since the optimization is nonlinear and includes variations of different types of variables, to solve the given problem the authors performed simulation tests and decided to implement a hybrid of two different optimization algorithms: artificial bee colony (ABC) and direct search algorithm (DSA). Simulation tests for the wastewater treatment plant case study are presented.

  • IMPROVING STUDENT SKILLS WITH ENGAGING IN HERITAGE PROTECTION PROJECTS. CASE STUDY OF ARCHITECTURAL INVENTORY WORKS AT WISŁOUJŚCIE FORTRESS, POLAND (2017)
    • Waldemar Ossowski
    • Tadeusz Widerski
    • Joanna Dąbal
    • Maciej Flis
    2019

    Today's educational offer at universities contains a lot of theoretical and general knowledge, which becomes less understandable and less suitable for students of the new generation. Student's educational needs aimed at increasing the practical experience necessary for future professional life. Heritage conservation projects are a good opportunity to implement project-based learning methods. Such projects can be scientific and technical research. In 2017, as part of the cooperation of the Gdańsk Museum, the University of Gdańsk and the Gdańsk University of Technology, pilot interdisciplinary research activities were undertaken in the Wisłoujście Fortress in Poland. The project includes an innovative educational path aimed at implementing new digital documentation methods, standard academic research of monuments and gathering archival information. The first tasks were focused on architectural inventory and archaeological research in the post-medieval area. The main purpose of these proceedings was the preliminary functional interpretation of the interiors studied. A lot of new data was collected that explained the unknown building history. Students were trained in the field of measurement systems, photogrammetric documentation and the history of building materials. In addition, students processed data by creating 3D models of documented structures. All implemented activities were aimed at involving the students of both institutions in the history of the Wisłoujście Fortress. Participation in the implementation of "real" tasks contributed to the greater involvement of participants. The works they carried out were additionally disseminated in social media, initiating an open public debate on the subject of military heritage. Implementation of the monument protection project on the example of the Wisłoujście Fortress showed that through appropriate involvement of students from various scientific units, the impact range and effectiveness of the project implementation can be improved, the methods of learning students can be improved as well as the results of the works can be disseminated more widely.

  • Impulse Impedance Measurements of Lightning Protection Earthings
    • T. Horchue
    • W. Tangtheerajaroonwong
    • Stanisław Wojtas
    • Marek Wołoszyk
    2019

    Lightning protection earthing systems should be tested at currents with time parameters similar to those of lightnings. A method and definition of a measured value of impulse impedance are introduced. The impulse impedance was determined by a quotient of voltage drop on the tested earthing to a value of current in measure circuit. The usefulness of the impulse method for lightning protection evaluation is tested on radio base stations tower, transmission line towers, and buildings. Application of the earthing impulse meter is described in this paper.

  • In search of a common ground for the space sciences
    • Edmund Wittbrodt
    • Zdzisław Brodecki
    2019

    The paper discusses the relations between various aspects of human activities performed in space, taking into consideration the past, present and future contexts. Interdisciplinarity and integrity of technological issues combined with legal and management issues were emphasized. Consequently, it was recognized that it is necessary to build a network of universities, research-and-development companies and engineering companies. A particular attention was dedicated to the current situation in Poland and conditions necessary to achieve a European level.

  • In situ study of a composition of outlet gases from biogas fuelled Solid Oxide Fuel Cell performed by the Fourier Transform Infrared Spectroscopy
    • Mikołaj Chlipała
    • Patryk Błaszczak
    • Sea-Fue Wang
    • Piotr Jasiński
    • Beata Bochentyn
    2019 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The purpose of this study was to develop a method and software based on the Fourier Transform Infrared Spectroscopy for the in-situ, quantitative analysis of the composition of outlet gases from Solid Oxide Fuel Cell (SOFC). The calibration procedure performed at the beginning of the experiment indicated a polynomial dependence between the concentration of a calibrating gas (CO, CO2, CH4) and the corresponding integrated absorbance in particular wavenumber ranges. Further, it allowed determining a concentration of CO2, CO, CH4 and H2 in the outlet gas stream of the Ni-YSZ anode supported Direct Internal Reforming-SOFC fuelled by synthetic biogas (mixture of CO2 and CH4 in a volume ratio 2:3). The analysis was performed for over 90 h. Based on calculated concentration the conversion rates for both CH4 and CO2 gases were calculated, as well as the yields and selectivities of CO and H2. Also, the carbon balance was determined. In order to predict the direction of particular reforming reactions, a non-equilibrium analysis was performed. Namely, a thermodynamic probability of solid carbon formation was determined based on calculations of carbon activity coefficients. Obtained results indicated degradation of a fuel cell and corresponded well with electrical measurements where a decrease of power density in wet synthetic biogas was observed.

  • In Situ Verification of Numerical Model of Water Hammer in Slurries
    • Apoloniusz Kodura
    • Katarzyna Weinerowska-Bords
    • Wojciech Artichowicz
    • Michal Kubrak
    • Pawel Stefanek
    2019 Full text JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME

    This paper presents a numerical model of transient flow in a pressure slurry pipeline network with verification based on in situ measurements. The model, primarily verified in laboratory conditions, has been extended and applied to the case of a large and complex slurry pipeline network in Poland. In the model, the equivalent density concept was applied. In situ experiments were performed for various unsteady flow episodes, caused by different pump operation strategies in the industrial pipeline network. Based on the measurements of slurry concentration and pressure variations, the numerical model was tested and verified. A satisfactory coincidence between the calculated and the observed pressure characteristics was achieved. Additional numerical tests led to important conclusions concerning safe pump and valve operation and system security threats.

  • Incorporating Iris, Fingerprint and Face Biometric for Fraud Prevention in e-Passports Using Fuzzy Vault
    • Katarzyna Bobkowska
    • Khaled Ahmed Nagati
    • Marek Przyborski
    2019 Full text IET Image Processing

    A unified frame work which provides a higher security level to e-passports is proposed. This framework integrates face, iris and fingerprint images. It involves three layers of security: the first layer maps a biometric image to another biometric image which is called biostego image. Three mapping schemes are proposed: the first scheme maps single biometric image to single biostego image, the second scheme maps dual biometric images to single biostego image, the third scheme divides the biometric image into sections and maps each section to different biostego image. A mapping function maps the intensity value of each pixel in the biometric image to pixels with same intensity in the biostego image. A representative pixel is randomly selected from the set of pixels, its coordinates are recorded in the location map of the biometric image. In the second layer, the location map is encoded using fingerprint fuzzy vault. In the third layer, the encoded location map is hidden in the biostego image using steganography technique. The biostego image which contains the encoded location map is stored in the e-passport’s memory. Keeping the mapping scheme secret and by using the fingerprints fuzzy vault to encrypt location map the proposed approach provides higher level of protection against fraud.

  • Increasing K-Means Clustering Algorithm Effectivity for Using in Source Code Plagiarism Detection
    • Patrik Hrkút
    • Michal Ďuračík
    • Miroslava Mikušová
    • Mauro Callejas-cuervo
    • Joanna Żukowska
    2019

    The problem of plagiarism is becoming increasingly more significant with the growth of Internet technologies and the availability of information resources. Many tools have been successfully developed to detect plagiarisms in textual documents, but the situation is more complicated in the field of plagiarism of source codes, where the problem is equally serious. At present, there are no complex tools available to detect plagiarism in a large number of software projects, such as student projects, which are created hundreds per year at each faculty of informatics. Our project aim is to create such a system for finding plagiarism in a large dataset of source codes. The whole system consists of several parts. A classification of source code is an essential part of the whole system because it makes it much more efficient to manipulate source code and divide data into individual clusters so that searching in large volumes of source code is as efficient as possible. The paper discusses how to optimize the implementation of clustering, so the whole system would deliver results in a reasonable time because allocating the different parts of the source code into suitable clusters will allow faster and more memory-efficient search for similar parts of the code.

  • Increasing the Seismic Resistance of Wood-frame Buildings by Applying PU Foam as Thermal Insulation
    • Wojciech Migda
    • Marcin Szczepański
    • Robert Jankowski
    2019 Full text Periodica Polytechnica-Civil Engineering

    Wood-frame buildings are very common in regions that are exposed to earthquakes. Most of residential buildings are constructed using this technology; therefore, the seismic resistance of them is really essential in order to prevent human losses and structural damage. The aim of the present article is to show the results of the detailed numerical FEM analysis focused on the seismic behaviour of the wood-frame house with different in-wall insulation materials. The results of the study clearly indicate that using polyurethane (PU) foam instead of mineral wool leads to the increase in the rigidity of the structure and, therefore, to the substantial reduction in the structural response under different seismic excitations. The results also show that, generally speaking, the level of reduction in the displacement response increases with the increase in the magnitude of the earthquake, which even furthermore benefits the application of PU foam as an insulation material. It has also been concluded that the method of using PU foam can be successfully applied not only in the newly constructed wood-frame houses but also in existing ones since replacing the mineral wool with PU foam is relatively easy and not so much expensive.

  • In-depth characterization of icosahedral ordering in liquid copper
    • Szymon Winczewski
    • Jacek Dziedzic
    • Jarosław Rybicki
    2019 Full text COMPUTATIONAL MATERIALS SCIENCE

    The presence of icosahedral ordering in liquid copper at temperatures close to the melting point is now well-established both experimentally and through computer simulation. However, a more elaborate analysis of local icosahedral and icosahedron-like structures, together with a system for classifying such structures based on some measure of "icosahedrity", has so far been conspicuously absent in the literature. Similarly, the dynamics of these structures has not yet received the attention it merits. We present a new method for structural analysis, which combines Voronoi analysis with bond-orientational order parameters, and apply it to liquid Cu configurations obtained from tight-binding molecular dynamics at a range of temperatures near the melting point. We introduce a clear system for classifying local structures according to their degree of similarity to the perfect icosahedron, and show how their energies of formation correlate with our structural descriptor. We examine the frequencies of occurrence for the classes of Voronoi polyhedra we distinguish, calculate their lifetimes, and establish the temperature dependence of these properties. We explore the dynamics of icosahedron-like structures by examining how individual classes transform between one another. Finally, we perform structural correlation analysis, demonstrating, among other things, that icosahedra and icosahedron-like structures preferentially connect and show a tendency towards clustering. We believe our approach can be readily applied in studies of icosahedral ordering in liquid metals or metallic glasses.

  • Induction of chirality in 4,4'-azopyridine by halogen-bonding interaction with optically active ditopic donors
    • Jan Alfuth
    • Jarosław Chojnacki
    • Tadeusz Połoński
    • Teresa Olszewska
    2019 NEW JOURNAL OF CHEMISTRY

    Optically active ditopic halogen bond donors bearing two 4-iodotetrafluorophenyl groups were obtained by reaction of chiral diols with iodopentafluorobenzene. Co-crystallization of these donors with anti-4,4′-azopyridine afforded binary complexes containing infinite chains of the alternating component molecules connected by halogen bonds. The solid state CD measurements confirmed that complexation induces optical activity of the azo chromophore due to the twisting of the aryl-N=N system or external chiral perturbation exerted by host molecules.