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  • Equivalent standard manoeuvres for pod-driven ships
    • Maciej Reichel
    2019 OCEAN ENGINEERING

    Procedures for carrying out the manoeuvring tests presented in International Maritime Organisation (IMO) resolution MSC.137(76) are based on the capabilities of ships with conventional steering-propulsion systems. Therefore they do not correspond to ships with other steering-propulsion devices, like pod drives. IMO is aware of this shortcoming and for ships with non-conventional steering and propulsion system may permit the use of comparative steering angles to the rudder angles specified by the resolution. To elaborate these comparative angles for pod-driven gas carrier, experiments with free-sailing manned model have been carried out. For comparison two sister ships have been taken into consideration, i.e. twin-pod and twin-propeller twin-rudder configurations. For both ship versions, manoeuvres according to standard IMO procedures have been carried out. For twin-pod configuration, additionally manoeuvres with various pod propulsor settings have been performed to find the comparative, i.e. rudder-equivalent pod propulsor angles. Results show an obvious fact, that for twin-pod ship version similar results of standard manoeuvre parameters, as for twin-propeller twin-rudder version, are obtained for other than IMO recommended 35° steering angle. It is shown that, for turning circle parameters, a single comparative or rudder-equivalent angle does not exist. Various turning circle parameters are obtained for different pod propulsor angles.

  • Equivalent temperature for design of asphalt pavements in Poland
    • Marek Pszczoła
    2019 Pełny tekst MATEC Web of Conferences

    The paper presents application of equivalent temperature for design of asphalt pavements. The calculation methods of equivalent temperature: the Shell method, the French method, the methods that use the AASHTO and the Asphalt Institute fatigue criteria were presented. The results of calculations of equivalent temperature for Polish climatic conditions were presented and discussed. It was shown that different asphalt pavement design methods and utilization of Polish climatic data resulted in various calculated values of equivalent temperature that could be used in the design process.

  • Ergonomic Aspects of Development of Architecture in the Context of Sanitary and Hygiene Safety
    • Rafał Janowicz
    2019 Advances in Intelligent Systems and Computing

    Abstract Ergonomics answers the need of safe development of space by creating spatial forms which help to implement the safety procedures and limit the threats involved both in ordinary use of the spaces and in case of unforeseen events. Using the knowledge of ergonomics and architecture on the basis of defining the routes of germ transmission, allows to limit the spread of those organisms. Ergonomics of developing architectural spaces allows to improve safety of all users. Changing reality, including the risks and the level of knowledge about those risks results in the fact that development of architecture with the use of ergonomics is not only a multi-dimensional issue, but also requiring constant analysis and validation of solutions due to a changing character of those risks. The work is an attempt to present how the deficit of detailed ergonomic guiding principles in the process of programming and designing of architectural objects experienced in Poland influences the sanitary and hygiene safety.

  • Erozja Kawitacyjna Austenitycznej Stali Nierdzewnej 1.4541
    • Dominika Zakrzewska
    • Alicja Krella
    • Grzegorz Gajowiec
    2019

    Proces erozji kawitacyjnej powoduje niszczenie materiału, na który składają się: odkształcenie plastyczne, ubytki masy, zmiany fazowe, fragmentacja ziaren, zmiany mikrogeometrii i makrogeometrii powierzchni. Różnorodność czynników mająca wpływ na proces niszczenia materiału sprawia, iż trudno jest przewidzieć postęp procesu niszczenia ciała stałego wskutek kawitacji. Z tego względu badania doświadczalne cały czas są niezbędne. Wiele badań nad różnymi materiałami wykazały, że odporność kawitacyjna zależy nie tylko od jednej własności materiału, ale również od intensywności zjawiska kawitacji. W pracy przedstawiono wyniki badań erozji kawitacyjnej austenitycznej stali nierdzewnej 1.4541. Przeprowadzone badania wykazały wpływ prędkości przepływu cieczy (ciśnienia wlotowego) na wielkość ubytków masy, szybkość erozji oraz obszar degradacji powierzchni. Ponadto, zaobserwowany charakter zniszczeń okazał się typowy dla badanego gatunku stali.

  • Establishing intelligent enterprise through community of practice for product innovation
    • Mohammad Waris
    • Cesar Sanin
    • Edward Szczerbicki
    2019 Pełny tekst JOURNAL OF INTELLIGENT & FUZZY SYSTEMS

    This paper presents the idea of implementing the virtual Community of Practice for Product Innovation processes towards the establishment of intelligent enterprise. Since the fourth industrial revolution is passing through the developing phase, implementation of Cyber-Physical Production Systems require more realistic approach. Knowledge Management and Engineering plays an important role in manufacturing industries facing global competition. One of the most promising areas where Knowledge Management is studied and applied is product innovation. This paper explains the efficient and systematic methodology for Knowledge Management through Community of Practice for product innovation. Manufacturing industries can connect with similar industries at global level, sharing and using technical and experiential knowledge in decision making thus converting them into intelligent enterprises.

  • Estimating Traffic Intensity Employing Passive Acoustic Radar and Enhanced Microwave Doppler Radar Sensor
    • Andrzej Czyżewski
    • Józef Kotus
    • Grzegorz Szwoch
    2019 Pełny tekst Remote Sensing

    Innovative road signs that can autonomously display the speed limit in cases where the trac situation requires it are under development. The autonomous road sign contains many types of sensors, of which the subject of interest in this article is the Doppler sensor that we have improved and the constructed and calibrated acoustic probe. An algorithm for performing vehicle detection and tracking, as well as vehicle speed measurement, in a signal acquired with a continuous wave Doppler sensor, is discussed. A method is also experimentally presented and studied for counting vehicles and for determining their movement direction by means of acoustic vector sensor application. The assumptions of the method employing spatial distribution of sound intensity determined with the help of an integrated three-dimensional (3D) sound intensity probe are discussed. The enhanced Doppler radar and the developed sound intensity probe were used for the experiments that are described and analyzed in the paper.

  • Estimation of electrode contact in capacitive ECG measurement
    • Adam Bujnowski
    • Mariusz Kaczmarek
    • Jerzy Wtorek
    • Kamil Osiński
    • Dominika Strupińska
    2019 Pełny tekst

    In the paper a method of electrode’s contact estimation in capacitive electrocardiogram (CECG) is presented. Proposed solution allows estimation of contact quality for each individual electrode. This enables construction of multi-electrode CECG systems, where electrode pairs can be selected on the basis of the individual electrode contact quality.

  • Estimation of wind pressure acting on the new palm house in Gdansk
    • Jacek Chróścielewski
    • Mikołaj Miśkiewicz
    • Bartosz Sobczyk
    • Krzysztof Wilde
    2019 Pełny tekst AIP Conference Proceedings

    This paper deals with the problem of numerical simulations of wind loads acting on a Palm House with complex geometry. Flow simulations with aid of computational fluid dynamics procedures have been performed to check if the pressure distributions for the structure are greater than those calculated using the standard design codes with assumption that the Palm House horizontal cross sections are described by smooth cylinders.

  • ESTYMACJA WSPÓŁCZYNNIKÓW SZTYWNOŚCI ZAMOCOWANIA PODATNEGO PRZEDMIOTU OBRABIANEGO NA STOLE FREZARKI
    • Michał Mazur
    • Marek Galewski
    • Krzysztof Kaliński
    2019

    W pracy przedstawiono metodę estymacji współczynników sztywności Elementów Sprężystych (ES) modelujących zamocowanie podatnego wielkogabarytowego przedmiotu obrabianego na stole frezarki. Proponowana metoda bazuje na algorytmie optymizacji za pomocą roju cząstek (ang. Particle Swarm Optimization), który pozwala na uzyskanie dobrej zgodności (aktualizacji) modelu Metody Elementów Skończonych (MES) z modelem pochodzącym z identyfikacji danych eksperymentalnych. Uzyskany w ten sposób model MES może być wykorzystywany do dalszych symulacji zarówno w dziedzinie czasu, jak i dziedzinie częstotliwości.

  • Evaluati on of long-term start up costs impact on short-term price based operational optimization of a CCGT using MILP
    • Sylwia Gotzman
    • Paweł Ziόłkowski
    • Janusz Badur
    2019 Pełny tekst E3S Web of Conferences

    An increasing share of the weather-dependent RES generation in the power system leads to the growing importance of flexibility of conventional power plants. They were usually designed for base load operation and it is a challenge to determine the actual long-term cycling costs, which account for an increase in maintenance and overhaul expenditures, increased forced outage rates and shortened life expectancy of the plant and components. In this paper, the overall impact of start up costs is evaluated by formulating and solving price based unit commitment problem (PBUC). The electricity spot market is considered as a measure for remunerating flexibility. This approach is applied to a real-life case study based on the 70 MWe PGE Gorzów CCGT power plant. Different operation modes are calculated and results are used to derive a mixed integer linear programming (MILP) model to optimize the operation of the plant. The developed mathematical model is implemented in Python within the frame of the PuLP library and solved using GUROBI. Results of the application of the method to a numerical example are presented.

  • Evaluating Accuracy of Respiratory Rate Estimation from Super Resolved Thermal Imagery
    • Alicja Kwaśniewska
    • Maciej Szankin
    • Jacek Rumiński
    • Mariusz Kaczmarek
    2019 Pełny tekst

    Non-contact estimation of Respiratory Rate (RR) has revolutionized the process of establishing the measurement by surpassing some issues related to attaching sensors to a body, e.g. epidermal stripping, skin disruption and pain. In this study, we perform further experiments with image processing-based RR estimation by using various image enhancement algorithms. Specifically, we employ Super Resolution (SR) Deep Learning (DL) network to generate hallucinated thermal image sequences that are then analyzed to extract breathing signals. DL-based SR networks have been proved to increase image quality in terms of Peak Signal-to-Noise ratio. However, it hasn’t been evaluated yet whether it leads to better RR estimation accuracy, what we address in this study. Our research confirms that for estimator based on the dominated peak in the frequency spectrum Root Mean Squared Error improves by 0.15bpm for 8-bit and by 0.84bpm for 16-bit data comparing to original sequences if hallucinated frames are used. Mean Absolute Error is reduced by 0.63bpm for average aggregator and by 2.06bpm for skewness. This finding can enable various remote monitoring solutions that may suffer from poorer accuracy due to low spatial resolution of utilized thermal cameras.

  • Evaluating Performance and Accuracy Improvements for Attention-OCR
    • Adam Brzeski
    • Kamil Grinholc
    • Kamil Nowodworski
    • Adam Przybyłek
    2019

    In this paper we evaluated a set of potential improvements to the successful Attention-OCR architecture, designed to predict multiline text from unconstrained scenes in real-world images. We investigated the impact of several optimizations on model’s accuracy, including employing dynamic RNNs (Recurrent Neural Networks), scheduled sampling, BiLSTM (Bidirectional Long Short-Term Memory) and a modified attention model. BiLSTM was found to slightly increase the accuracy, while dynamic RNNs and a simpler attention model provided a significant training time reduction with only a slight decline in accuracy.

  • Evaluating the effect of different operational strategies on the carbon footprint of wastewater treatment plants – case studies from northern Poland
    • Mojtaba Maktabifard
    • Ewa Zaborowska
    • Jacek Mąkinia
    2019 Pełny tekst WATER SCIENCE AND TECHNOLOGY

    Nowadays, low greenhouse gas (GHG) emission is expected at wastewater treatment plants (WWTPs). However, emission quantification and evaluation still faces difficulties related to data availability and uncertainty. The objective of this study was to perform carbon footprint (CF) analysis for two municipal WWTPs located in northern Poland. Slupsk WWTP is a large biological nutrient removal (BNR) facility (250,000 PE) which benefits from on-site electricity production from biogas. The other studied plant is a medium-size BNR facility in Starogard (60,000 PE). In this WWTP, all the required electricity was provided from the grid. Both wastewater systems were composed of activated sludge, with differences in the nutrient removal efficiency and sludge treatment line. The CF calculations were based on empirical models considering various categories of input parameters, afterwards summing up the emissions expressed in CO2 equivalents (CO2e). After sensitivity analysis, significant contributors to GHG emissions were identified. The total specific CF of the Slupsk and the Starogard WWTP was 17.3 and 38.8 CO2e per population equivalent (PE), respectively. In both cases, sludge management, electricity consumption and direct emissions from wastewater treatment were found to significantly influence the CF. A substantial share of the total CF originated from indirect emissions, primarily caused by the energy consumption. This negative impact can be partially overcome by increasing the share of renewable energy sources. Reduction of over 30% in the total CF could be achieved while applying energy recovery from biogas by combined heat and power plants. Farmland and farmland after composting were found to be the most appropriate strategies for sludge management. They could create a CF credit (8% of the total CF) as a result of substituting a synthetic fertilizer. Reliable full-scale measurements of N2O emissions from wastewater treatment are recommended due to high uncertainty in CF estimation based on fixed emission factors (EFs). While applying the lowest and the highest N2O EFs reported in the literature, the total CF would change even by 2–3 times.

  • Evaluation of Facial Pulse Signals Using Deep Neural Net Models
    • Jacek Rumiński
    • Alicja Kwaśniewska
    • Maciej Szankin
    • Tomasz Kocejko
    • Magdalena Mazur-Milecka
    2019

    The reliable measurement of the pulse rate using remote photoplethysmography (PPG) is very important for many medical applications. In this paper we present how deep neural networks (DNNs) models can be used in the problem of PPG signal classification and pulse rate estimation. In particular, we show that the DNN-based classification results correspond to parameters describing the PPG signals (e.g. peak energy in the frequency domain, SNR, etc.). The results show that it is possible to identify regions of a face, for which reliable PPG signals can be extracted. The accuracy obtained for the classification task and the mean absolute error achieved for the regression task proved the usefulness of the DNN models.

  • Evaluation of Health Hazard Due to Emission of Volatile Organic Compounds from Various Processing Units of Wastewater Treatment Plant
    • Hubert Byliński
    • Jacek Gębicki
    • Jacek Namieśnik
    2019 Pełny tekst International Journal of Environmental Research and Public Health

    The paper describes an attempt at health risk assessment and odour concentration determination in the most important units of a wastewater treatment plant. The cancer risk (CR) and hazard index (HI) parameters in selected measurement locations were calculated based on the results of chromatographic analyses (GCxGC-TOF-MS) and the United States Environmental Protection Agency (US EPA) guidelines. No exceedance of the CR and HI acceptable levels was observed for identified and quantitatively determined compounds from the VOCs group. The acceptable level was exceeded for the summary HI parameter. Following a classification of the International Agency for Research on Cancer (IARC), it was noticed that the highest hazard was connected to the presence of formaldehyde belonging to group 1—the compounds regarded as carcinogenic. Based on the olfactometric analyses, it was estimated that the highest odour concentration, 37.2 ou/m3, occurred at the solid waste composting piles. It was also revealed that an increase in odour concentration corresponded to a higher health risk for employees of the wastewater treatment plant, due to exposure to volatile odorous compounds. Accordingly, this method of odour measurement can be a fast indicator describing health risk level.

  • Evaluation of Partial Nitritation/Anammox (PN/A) Process Performance and Microorganisms Community Composition under Different C/N Ratio
    • Hussein Al-Hazmi
    • Dominika Grubba
    • Joanna Majtacz
    • Przemysław Kowal
    • Jacek Mąkinia
    2019 Pełny tekst Water

    A one-stage partial nitritation/anammox (PN/A) process with intermittent aeration is possible under sidestream conditions, but implementation in a mainstream is a challenge due to increased Carbon/Nitrogen (C/N) ratios in domestic wastewater. This study investigated the effect of C/N ratios on process efficiency and the effect of narrowing non-aeration time on process improvement at high chemical oxygen demand (COD) load. An increase in TN removal efficiency was achieved in both series with gradual change of C/N ratio from 1 to 3, from 65.1% to 83.4% and 63.5% to 78% in 1st and 2nd series, respectively. However, at the same time, the ammonium utilization rate (AUR) value decreased with the increase in C/N ratio. At a high COD (C/N = 3) concentration, the process broke down and regained productivity after narrowing the non-aeration time in both series. Shifts in the system performance were also connected to adaptive changes in microbial community revealed by data obtained from 16S rRNA NGS (next-generation sequencing), which showed intensive growth of the bacteria with dominant heterotrophic metabolism and the decreasing ratio of autotrophic bacteria. The study shows that deammonification is applicable to the mainstream provided that the C/N ratio and the aeration/non-aeration time are optimized.

  • Evaluation of Praseodymium and Gadolinium Doped Ceria as a Possible Barrier Layer Material for Solid Oxide Cells
    • Bartosz Kamecki
    • Jakub Karczewski
    • Piotr Jasiński
    • Sebastian Molin
    2019 ECS Transactions

    In this work, nanocrystalline layers based on the Pr, Gd co-doped CeO2 were investigated. For the preparation of thin layers, lowtemperature spray pyrolysis technique was used. Different stoichiometries of the layers were produced for comparison on polished sapphire substrates. The microstructure of the prepared thin layers was studied by scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). The total electrical conductivity as a function of Gd or Pr dopant were determined by DC electrical measurements using the Van der Pauw method in air atmosphere. The oxygen electrode interface analysis confirm protective character of the diffusion barrier layer based on doped CeO2.

  • Evaluation of the glycerolysis process and valorisation of recovered polyol in polyurethane synthesis
    • Patrycja Jutrzenka Trzebiatowska
    • Hynek Beneš
    • Janusz Datta
    2019 Pełny tekst REACTIVE & FUNCTIONAL POLYMERS

    In this study, the glycerolysis of polyurethane (PU) foam and the applicability of obtained glycerolysate (GLY) for cast PUs were investigated. It was found that crude glycerine with purity grade of 84% might be successfully used for the glycerolysis. The optimal conditions were determined as follows: reaction time of 60 min at 220 °C using dibutyltin dilaurate catalyst (0.5%). Moreover, the purification of GLY by means of liquid-liquid extraction and distillation was also adapted. Cast PUs based on GLY were prepared using a two-step method, during which a prepolymer was first synthesised from a mixture of virgin polyol, GLY and 4, 4′-diphenylmethane diisocyanate (MDI). The prepolymer was then extended with a chain extender, 1, 4-butanediol or 1, 3-propanediol. The effect of virgin polyol replacement by GLY (up to 75%) on thermal and mechanical properties of the cast PUs was determined. The PUs based on GLY exhibited slightly lower thermal stability, higher storage modulus and higher glass transition temperature than the neat PU. The tensile strength of all prepared PUs was beneficially high (12–15 MPa), while the elongation at break decreased with the increasing GLY content probable due to the branching of PU chains.

  • Evaluation of the influence of grapevine growing conditions on wine quality
    • Magdalena Fabjanowicz
    • Klaudia Kosek
    • Justyna Płotka-Wasylka
    • Jacek Namieśnik
    2019 Pełny tekst MONATSHEFTE FUR CHEMIE

    Scientists are increasingly interested in the viticulture concept of terroir, which states that unique properties of wine are strictly related to the environmental conditions under which grapes are cultivated. The aim of the research was to compare the parameters characterizing wines produced in Poland, such as pH, conductivity, total organic carbon (TOC), and concentration of anions (F−, Cl−, NO2−, NO3−, PO43−, SO42−). It was shown that red wines were characterized by higher acidity and higher concentration of fluoride ions compared to white wines. All wine samples were characterized by a high concentration of phosphate ions which is associated with the process of soil fertilization with phosphorus compounds. A tentative chemometric analysis was performed in order to examine the correlations between the determined parameters. The results were compared in terms of the effect of soil type on the concentration of compounds contained in wine, and the pH and conductivity parameters. The analysis has shown that the soil in which the grapevines grow has a significant impact on the values of selected parameters and on the content of selected chemical compounds.

  • Evaluation of the prediction ability of air pollutants based on the electronic nose responses
    • Paweł Kalinowski
    • Łukasz Woźniak
    • Grzegorz Jasiński
    • Piotr Jasiński
    2019

    Electronic noses are able to perform on-line measurements of the toxic volatile compounds in air. Due to their low cost and compact size they can be placed in the areas exposed to pollution, outside the laboratory. Those advantages, on the other side, force the need for development of the reliable sensors data analysis procedures. One of the most important issues connected with electronic noses is the lack of stability of the gas sensors responses. This issue influence the overall performance of the measurement system. The methods of improvement of the reliability of the electronic noses are still under the scientific interests. In this work we present the results of the evaluation of the our-design electronic nose system. The measurement system was calibrated for the concentration prediction of the four toxic volatile compounds, namely nitrogen dioxide, carbon monoxide, ozone and sulfur dioxide. The prediction errors results are evaluated based on the measurements conducted together with the reference station at the PKN Orlen in Plock.

  • Evaluation of the stiffness modulus and phase angle of cold in-place recycled mix-tures for long curing periods
    • Bohdan Dołżycki
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2019

    Article 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 presents the results of stiffness modulus and phase angle for cold in-place recycled mixtures after 3 years of curing. Nine different mixtures with different combinations of cement and bituminous emulsion were tested using Simple Performance Tester. Stiffness modulus and phase angle were measured for three temperatures (4°C, 20°Cand 40°C) and for 9 different frequencies (from 0.01 Hz to 25 Hz). The obtained results confirmed that despite the strong action of hydraulic bonds and their increase over three years, CIR mixtures maintained intermediate behaviour between strictlyelastic and viscoelastic. While for lower test temperatures of 4°Cand 20°C a steady increase in stiffness modulus and a decrease in phase angle were observed with the time of curing, there were no changes in the values of both parameters measured atthe temperature of 40°C. In termsof relative values, theobserved changes were notremarkablyhigh for such a long term and ranged up to 25%. Nevertheless,in all the tested cases,with the passingof operational timematerialsbecame more elastic, which can result in improved resistance to permanent deformation, but also inhigher susceptibility to reflective cracking.

  • Evaluation of the use of reindeer droppings for monitoring essential and non-essential elements in the polar terrestrial environment
    • Aneta Pacyna-Kuchta
    • Marcin Frankowski
    • Krystyna Kozioł
    • Michał Węgrzyn
    • Paulina Wietrzyk-Pełka
    • Sara Lehmann-Konera
    • Żaneta Polkowska
    2019 SCIENCE OF THE TOTAL ENVIRONMENT

    Excess or toxic metals, non-metals and metalloids can be eliminated from the organism by deposition in inert tissue (e.g. fur) or excretion with body secretions, urine and faeces. Droppings are one of the main routes for the elimination of multiple elements and they can be collected without direct contact with the animal. Contaminant concentration has been examined in non-lethally collected tissues of several species (especially reptilian, avian and mammalian). However, studies on species residing in polar areas are still limited, especially of mammals from the European Arctic. Reindeers are the only large herbivores living in Svalbard, being an essential part of the Arctic terrestrial ecosystem. Although reindeer presence has a high impact on their surroundings, those huge mammals are rarely part of ecotoxicological studies regarding metal pollution. In this paper, the droppings of Svalbard reindeer were used as a non-invasively collected tissue to examine the excretion pathway of 30 elements. Samples were collected in mesic and moss tundra, representing summer, winter and winter-transitional excretion. For more than a half of the studied elements, significant differences occurred between the samples collected in the two tundra types. The feasibility of older and fresh samples was assessed based on summer droppings, and significant differences were found for K, As, Mn, Na, Ni, and Sb concentrations. No relevant differences in element levels were observed for samples collected from adult females, adult males and calves, except for zinc and potassium. Results show that reindeer droppings are an important vector for the transfer of many metals, non-metals and metalloids including calcium, phosphorus, zinc, aluminium and lead. As a sedentary species, feeding on local food sources, Svalbard reindeer is a valuable indicator of trace element presence in the polar terrestrial ecosystem.

  • Ewolucja od węgla do krzemu
    • Jarosław Wawer
    2019 Elektronika dla wszystkich

    Felieton popularnonaukowy dotyczący filozofii techniki.

  • Exact-match Based Wikipedia-WordNet Integration
    • Tomasz Boinski
    • Julian Szymanski
    • Tymoteusz Cejrowski
    2019 Pełny tekst

    Ability to link between WordNet synsets and Wikipedia articles allows usage of those resources by computers during natural language processing. A lot of work was done in this field, however most of the approaches focus on similarity between Wikipedia articles and WordNet synsets rather than creation of perfect matches. In this paper we proposed a set of methods for automatic perfect matching generation. The proposed methods were evaluated and integrated into one unified solution for generating matches with good quality. The paper describes and evaluates the proposed methods and presents the integration process. The evaluation of the final proposed solution is given.

  • Examination of fresh water chemistry in maritime Antarctica during austral summer 2017
    • Małgorzata Szopińska
    • Ruman Marek
    • Robert Józef Bialik
    • Żaneta Polkowska
    2019 Pełny tekst AIP Conference Proceedings

    Due to the fact that Antarctica is one of the least polluted places on Earth, it is a perfect place to observe the spread of global pollution. Therefore, research conducted on this continent is important due to the possibility of investigating the type of pollution and their way of transport. This work considers presence of organic contaminants in Maritime Antarctica in unexplored until now, Lions Rump headland. Qualitative and quantitative analysis of samples were carried out in order to determine the content of analytes such as polycyclic aromatic hydrocarbons (PAHs). Among all determined PAHs in water samples the highest concentrations was observed for naphthalene and anthracene, which is the result of their higher volatility in comparison to the High Molecular Weight PAHs. The presence of PAHs in the water environment may constitute potential negative effect on Antarctic ecosystem and it should be investigated in detail. Moreover, possibility of undertaking various actions reducing contaminants emission are also very important. We hope that improved fossil fuel economy, and not only on the local scale, would help reduce PAH levels in Maritime Antarctica.

  • Examining Ownership Equity as a Psychological Factor on Tourism Business Failure Forecasting
    • Tomasz Korol
    • Anastasia Spyridou
    2019 Pełny tekst Frontiers in Psychology

    This paper examines ownership equity as a predictor of future business failure within the tourism and hospitality sectors. The main goals of this study were to examine which ratios are the most important for a tourism business failure forecasting model and how significant is the “total percentage of equity ownership by company directors” ratio compared with other ratios associated with the probability of bankruptcy. A stepwise weight assessment ratio analysis (SWARA) was applied, and 12 tourism bankruptcy experts evaluated key ratios. Total percentage of equity ownership by company directors is considered a psychological factor, and it was identified as the fourth most important ratio for a business failure forecasting model. Academicians and practitioners can use the findings of this study whenever developing a forecasting model for tourism and hospitality enterprises.

  • Exchange-Traded Funds in Europe
    • Adam Marszk
    • Ewa Lechman
    2019

    Exchange-Traded Funds in Europe provides a single point of reference on a diverse set of regional ETF markets, illuminating the roles ETFs can play in risk mitigation and speculation. Combining empirical data with models and case studies, the authors use diffusion models and panel/country-specific regressions—as well as graphical and descriptive analyses— to show how ETFs are more than conventional, passive investments. With new insights on how ETFs can improve market efficiency and how investors can benefit when using them as investment tools, this book reveals the complexity of the world’s second largest ETF market and the ways that ETFs are transforming it.

  • Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
    • Anna Perelomova
    2019 Pełny tekst ACTA ACUSTICA UNITED WITH ACUSTICA

    The nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and mass fraction of reagent A, are taken into account. The instantaneous equations are derived which govern dynamics of perturbations in non-acoustic modes, and conclusions of the efficiency of their nonlinear excitation by sound are drawn. The advantage of this study is accurate description of dispersion. Acoustic perturbations of any characteristic duration as compared to the duration of chemical reaction are considered, along with periodic, aperiodic perturbations and impulses. The conclusions concern also acoustically active gases.

  • Excited state properties of a series of molecular photocatalysts investigated by time dependent density functional theory.
    • Miłosz Martynow
    • Kupfer Stephan
    • Sven Rau
    • Julien Guthmuller
    2019 Pełny tekst PHYSICAL CHEMISTRY CHEMICAL PHYSICS

    Time dependent density functional theory calculations are applied on a series of molecular photocatalysts of the type [(tbbpy)2M1(tpphz)M2X2]2+ (M1 = Ru, Os; M2 = Pd, Pt; X = Cl, I) in order to provide information concerning the photochemistry occurring upon excitation of the compounds in the visible region. To this aim, the energies, oscillator strengths and orbital characters of the singlet and triplet excited states are investigated. The structural modifications of the complexes have a strong impact on the excited states properties. In particular, it is found that the main differences concern the energies of the charge-separated and metal-centered states. The analysis of these differences provides general trends for the efficiency of population transfers between the states, particularly regarding the charge separation and electron recombination processes.

  • Experience based decisional DNA to support smart product design
    • Muhammad Ahmed
    • Cesar Sanin
    • Syed Imran Shafiq
    • Edward Szczerbicki
    2019 JOURNAL OF INTELLIGENT & FUZZY SYSTEMS

    This paper presents the idea of Smart Virtual Product Development (SVPD) system to support product design. The foundations of the system are based upon smart knowledge management techniques called Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). It enhances the industrial product development process by using the previous experiential knowledge gathered from the formal decisional activities. This experiential knowledge is collected from the group of similar products having some common functions and features. The developed system comprises of three modules: design knowledge management (DKM), manufacturing capability analysis and process planning (MCAPP), and product inspection planning (PIP). The working of design knowledge management module is presented in this study and is validated by using an industrial case study, which suggests that it is capable of capturing and reusing the required design knowledge for material selection process. The developed system has the capability to facilitate decision making and mistake proofing during early stages of product design. It can be beneficial for small and medium enterprises (SMEs) involved in product development.

  • Experience based knowledge representation for Internet of Things and Cyber Physical Systems with case studies
    • Cesar Sanin
    • Zhang Haoxi
    • Imran Shafiq
    • Md Waris
    • Caterine Silva de Oliveira
    • Edward Szczerbicki
    2019 Future Generation Computer Systems-The International Journal of Grid Computing-Theory Methods and Applications

    Cyber Physical Systems and Internet of Things have grown significant attention from industry and academia during the past decade. The main reason behind this interest is the capabilities of such technologies to revolutionize human life since they appear as seamlessly integrating classical networks, networked objects and people to create more efficient environments. However, enhancing these technologies with intelligent skills becomes an even more interesting and enticing scenario. In this paper, we propose and illustrate through a number of case studies how Decisional DNA, a multi-domain knowledge structure based on experience, can be implemented as a comprehensive embedded knowledge representation for Internet of Things and Cyber Physical Systems. Decisional DNA gathers explicit experiential knowledge based on formal decision events and uses this knowledge to support decision-making processes. The main advantages of using Decisional DNA are as follows: (i) offers a standardized form of the collected knowledge and experience, (ii) provides versatility and dynamicity of the knowledge structure, (iii) stipulates storage of day-to-day explicit experience in a single configuration, (iv) delivers transportability and shareability of the knowledge, and (v) provides predicting capabilities based on the collected experience. Consequently, test and results of the presented implementation of Decisional DNA case studies support it as a technology that can improve and be applied to the aforementioned technologies enhancing them with intelligence by predicting capabilities and facilitating knowledge engineering processes.

  • Experiences and Challenges in Fatality Reduction on Polish Roads
    • Kazimierz Jamroz
    • Marcin Budzyński
    • Aleksandra Romanowska
    • Joanna Żukowska
    • Jacek Oskarbski
    • Wojciech Kustra
    2019 Pełny tekst Sustainability

    According to the UN, road safety is the key to achieving sustainable development goals, yet the complexity of how road accidents happen makes this a difficult challenge leaving many countries struggling with the problem. For years, Poland has infamously been one of the EU’s top countries for road-accident fatality rates. Despite that, it has made significant progress in the last thirty years with a fatality reduction of more than 60%. A number of factors have contributed to this result: improving the socioeconomic situation, improving road safety measures, changing road user behaviour and changing national road safety programmes. This article presents Poland’s approach to road safety and, in particular, Vision Zero, adopted in 2005. Poland’s road safety changed over the years as the country learned from its successes and failures. Tools for forecasting fatalities were developed and used to identify the main factors that have helped to reduce deaths. An assessment was conducted on how Poland could implement Vision Zero until 2050 under different road safety scenarios. It was found that in order to achieve the EU’s goal for 2030, Poland must reduce fatalities to 1200. While it is an ambitious goal, it is also an important step towards zero fatalities in 2050.

  • Experiment-aided virtual prototyping to minimize tool-workpiece vibration during boring of large-sized structures
    • Krzysztof Jan Kaliński
    • Marek Galewski
    • Michał Mazur
    • Natalia Morawska
    2019 Pełny tekst

    The paper presents the author's method of solving the problems of vi-bration suppression during boring of large-sized workpieces by means of an in-novative method of adjusting the rotational speed of the boring bar. It consists in selecting the spindle speed in accordance with the results of the cutting process simulation. The method includes identification of the model of the finite element method of the boring bar. The Root Mean Square (RMS) values of the time plots and dominant values of the peaks in the frequency spectra were obtained during the boring process. The effectiveness of the proposed attempt is demonstrated by the selected mechatronic design technique, known as Experiment-Aided Vir-tual Prototyping (E-AVP). The proposed method has been verified based on the results of experimental research.

  • Experimental and numerical analysis of the modified TB32 crash tests of the cable barrier system
    • Dawid Bruski
    • Stanisław Burzyński
    • Jacek Chróścielewski
    • Kazimierz Jamroz
    • Łukasz Pachocki
    • Wojciech Witkowski
    • Krzysztof Wilde
    2019 ENGINEERING FAILURE ANALYSIS

    Road restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed by EN 1317 standard was analysed. For this purpose, a full-scale crash test was performed and on the basis of this the validation process of numerical simulations was carried out. Correctly and carefully developed numerical simulations give unique insight into the impact mechanism and allows for comprehensive understanding of barrier responses. The accuracy of the numerical models was assessed by comparing the results of the simulation with the crash test. The research showed that the analysed barrier work correctly, it contained and then properly redirected 1500 kg car back onto the road and ensured safety for the vehicle occupants at the same time.

  • Experimental determination of H2 mass stopping powers for low-energy electrons
    • Mateusz Zawadzki
    • Murtadha Khakoo
    2019 Pełny tekst PHYSICAL REVIEW A

    We present experimental mass stopping powers of electrons in gaseous H2 obtained with an electron time- of-flight spectrometer, for the incident electron energy range of 11 to 25 eV. In our procedure, the average energy loss is derived from conversion of the measured electron time-of-flight spectra into equivalent electron energy-loss spectra. Our present results are compared with the only available experimental measurement and with theoretical models. The measurements are a significant improvement to the available experimental data to date.

  • Experimental investigation into surface texture effect on journal bearings performance
    • Lidia Galda
    • Jaroslaw Sep
    • Artur Olszewski
    • Tomasz Żochowski
    2019 TRIBOLOGY INTERNATIONAL

    The aim of this study was to analyse the performance of journal bearings with specially created dimples on the sliding surface and operating under various conditions. The texture was created on the bearing surface that co-acted with the smooth journal; moreover, the variation of the textured surface of the journal mating with the smooth bearing was tested, and the results were compared to those obtained with the standard smooth journal bearing.

  • Experimental investigation of heat transfer enhancement in straight and U-bend double-pipe heat exchanger with wire insert
    • Rafał Andrzejczyk
    • Tomasz Muszyński
    • Przemysław Kozak
    2019 CHEMICAL ENGINEERING AND PROCESSING

    In this paper, the possibility of heat transfer enhancement in the U-bend exchanger was presented. Experimental research has been carried out for four individual heat exchanger constructions i.e. plain tube in tube, turbulized tube in tube, plain U-bend and U-bend with turbulator. Also, heat transfer experiments for various boundary conditions were performed to obtain reference values. In case of U-bend exchanger with and without turbulator, tests were conducted based on the water-water system. The study covered a wide measuring range, i.e. Re = 800–9000 - on the jacket side, Pel = 500–1400 W (for reference) cold water temperature of 9°C and hot water of 50°C. The exchangers were made from a copper pipe with an external diameter of 10 mm and 18 mm and wall thickness of 1 mm. The helicoidal vortex generator was made from brass wire with a diameter of 2.4 mm, coil diameter 13 mm and pitch 11 mm. For these geometries, the values of pressure drop and rate of heat transfer were determined. The comparison of heat transfer efficiency was performed based on NTU-ε method. For the same thermal-flow parameters, wire inserts provide up to 280% heat transfer enhancement and 85% higher heat transfer rate.

  • Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
    • Łukasz Skarżyński
    • Andrzej Tejchman-Konarzewski
    2019 Pełny tekst MATERIALS CHARACTERIZATION

    The paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation process, i.e. without beams' unloading for scanning. The shape, volume, size of cracks and pores were non-destructively measured during deformation. The maximum crack width during continuous micro-CT scanning was higher by about 20–30% than in the beam that was subjected to unloading for scanning.

  • Experimental research on marine oil-lubricated stern tube bearing
    • Wojciech Litwin
    2019 Pełny tekst PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY

    Bearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal bushing lubricated with mineral oil, which was subjected to experimental tests, has a number of advantages. First of all, it works in the area of full fluid friction, and in typical shipbuilding conditions it has a significant excess of hydrodynamic load capacity. Therefore, replacing mineral oil with an environmentally friendly lubricant with a similar viscosity seems to be a promising solution. Motion resistance larger than that in water-lubricated bearings compensates for the reliability and durability of this solution.

  • Experimental Research on the Energy Efficiency of a Parallel Hybrid Drive for an Inland Ship
    • Wojciech Litwin
    • Wojciech Leśniewski
    • Daniel Piątek
    • Karol Niklas
    2019 Pełny tekst ENERGIES

    The growing requirements for limiting the negative impact of all modes of transport on the natural environment mean that clean technologies are becoming more and more important. The global trend of e-mobility also applies to sea and inland water transport. This article presents the results of experimental tests carried out on a life-size, parallel diesel-electric hybrid propulsion system. The eciency of the propulsion system was analysed for two modes of operation (electric and diesel) and for dierent engine speeds and loads. Analysis of the impact of using a hybrid propulsion system on fuel consumption was carried out on a case study vessel and for six actual journeys. The use of hybrid propulsion in “zero emission” mode enables up to four times higher energy eciency when compared to a conventional drive, while reducing CO2 emissions and air pollution to zero, as well as a hundred-fold reduction in noise emissions. High flexibility in the operation of such a drive enables the use of intelligent power control technology (smart propulsion). This article shows that the use of hybrid propulsion reduces the negative impact on the environment to a minimum and allows for a significant reduction in the vessel’s operating costs.

  • Experimental studies on the impact of changing the pipe material on the propagation of the pressure wave during water hammer
    • Natalia Krystyna Gietka
    2019 Pełny tekst Acta Scientiarum Polonorum Formatio Circumiectus

    Aim of the paper is to present the results studying the water hammer phenomenon in pipes made of different materials, and to show the impact of changing the type of material of the pipe on the velocity of the pressure wave during the transient flow in the pipes. In terms of research material and methods, pipes made of galvanized steel and high-density polyethylene were tested. Measurements were made using strain gauges with a high accuracy of measurement. The results of the pressure wave velocity range from 205 to 247 m/s for the polyethylene pipe, and from 426 to 1351 m/s for the steel pipe. Therefore, the change in the type of the pipe material has a significant effect on the velocity of the pressure wave during the water hammer. The value of this velocity is influenced not only by the properties of the material itself or of the liquid, but also of the length of the sections and their position relative to each other. It is evident that the velocity in the polyethylene pipe does not change significantly in relation to the situation where the pipe has constant material characteristics. The situation is radically different in the case of a steel pipe, where the velocity of the pressure wave changes along with the length of the pipe and its position relative to the tank. The lowest value of the velocity in the elastic pipe is achieved when the latter is on the valve side and is only 13.15 m long, while the highest value is reached when the 13.24 m steel pipe is located on the side of the tank.

  • Experimental study and comparison with predictive methods for flow boiling heat transfer coefficient of HFE7000
    • Blanka Jakubowska
    • Dariusz Mikielewicz
    • Michał Klugmann
    2019 Pełny tekst INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

    This article describes an experimental study of flow boiling of HFE7000 inside a smooth vertical channel. The investigation has been carried out in a circular stainless-steel tube with an inner diameter of 2.3 mm. The data have been collected for the applied heat fluxes q ranging from 61 to 205 kW/m2, the mass flux G ranging from 214 to 1006 kg/(m2 s), the saturation temperature Tsat ranging from 30 to 54 °C and the full range of vapour quality x. The collected experimental data base amounted to 1217 experimental points. The acquired results indicated that heat flux and saturation temperature have the most significant impact on the heat transfer coefficient. The local heat transfer coefficient increases with both the heat flux and saturation temperature, while the mass flux did not exhibit a significant effect on the variation of the heat transfer coefficient. The present experimental data have been compared with various heat transfer correlations from literature including the recently enhanced in-house model. The results of comparisons indicated the superiority of the in-house model over other correlations.

  • Experimental Study on Dynamics of Wooden House Wall Panels with Different Thermal Isolation
    • Marcin Szczepański
    • Wojciech Migda
    • Robert Jankowski
    2019 Pełny tekst Applied Sciences-Basel

    Wood frame buildings are very popular in regions that are exposed to different dynamic excitations including earthquakes. Therefore, their seismic resistance is really important in order to prevent structural damages and human losses. The aim of the present paper is to show the results of experimental tests focused on the dynamic response of wall panels of a wooden frame building with thermal isolation made of mineral wool and polyurethane foam. Firstly, the static and the dynamic mechanical analysis (DMA) tests were conducted so as to determine the basic thermomechanical properties of the analyzed isolation materials. Then, the elements of the exterior walls with two types of thermal insulation were tested under harmonic excitation for different amplitudes of displacement. The results of the static material tests indicate that the polyurethane foam behaves in a highly nonlinear way both during compression and tension. Moreover, the results of the DMA tests show that the storage and loss modulus of the polyurethane foam are significantly larger in relation to the values obtained for the mineral wool. The results of the dynamic tests on wall panels show that the use of polyurethane foam as thermal isolation leads to a substantial increase in stiffness and damping properties, as compared to the case when the mineral wood is used.

  • Experimental study on models of cylindrical steel tanks under mining tremors and moderate earthquakes
    • Daniel Burkacki
    • Robert Jankowski
    2019 Earthquakes and Structures

    The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical steel tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled steel tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.

  • Experimental study on single phase operation of microjet augmented heat exchanger with enhanced heat transfer surface
    • Tomasz Muszyński
    • Rafał Andrzejczyk
    2019 APPLIED THERMAL ENGINEERING

    The article presents experimental investigations on a prototype heat exchanger. Presented research is focused on combined active and passive enhancement techniques of surface modification and microjet impingement. The results were compared to reference plate heat exchanger without microjet impingement. The Wilson plot method was applied to determine the heat transfer coefficients in the single phase operation. The heat exchanger was capable of exchanging 300 W of thermal energy at LMTD of 40 K. The obtained overall heat transfer rates reach 600 W/m2. Introducing knurled surface resulted in ∼10% increase heat transfer area, and similar enhancement in transferred heat in reference to plate heat exchanger geometry. Knurled surface decreased heat transfer in combination with a multi-jet impingement in comparison to a smooth surface. A possible explanation of that effect is that the flow in wall jet region is disrupted by the knurled surface and directed in the bulk of the fluid. Initiating mixing with colder fluid, thicker thermal boundary layer, and affecting local temperature distribution.

  • Experimental tests of lintel hybrid beams
    • Krystyna Nagrodzka-Godycka
    • Maciej Tomasz Solarczyk
    • Marek Wesołowski
    2019

    The results of experimental tests of lintel hybrid beams made of air concrete and prestressed concrete were presented in paper. Blocks of air concrete was a protective element for the construction one. The length of hybrid beams was 3.0 m, while total height 27 cm. It was assumed that hybrid beams will work in the simply-supported scheme (with a 10 cm support) loaded uniformly over the entire length. The object of the tests were beams with the same geometry differing in the position of the prestressed wire. In the first considered case the wire was located at a distance of 6.5 cm from the bottom edge of the construction part (prestressed concrete) of beam, while in the second case: 13 cm from the bottom edge of the construction part of beam. The experimental tests under static monotonous load up to the failure were examined. The paper shortly described the designing stage of project. Hybrid beams were calculated with Limit State Method and Allowable Stress Method. Some assumptions for element calculations were also presented.

  • Experimentally feasible semi-device-independent certification of four-outcome positive-operator-valued measurements
    • Piotr Mironowicz
    • Marcin Pawłowski
    2019 Pełny tekst PHYSICAL REVIEW A

    Recently the quantum information science community devoted a lot of attention to the theoretical and practical aspects of generalized measurements, the formalism of all possible quantum operations leading to acquisition of classical information. On the other hand, due to imperfections present in quantum devices, and limited thrust to them, a trend of formulating quantum information tasks in a semi-device-independent manner emerged. In this Rapid Communication we use the concept of quantum random access codes to construct a protocol able to certify the presence of the generalized measurements in a semi-device-independent way without employing quantum entanglement. We use semidefinite programming methods to show robustness of the protocol and characterize its statistical properties. We conclude that it allows for experimental realizations using technology currently available in laboratories.

  • Exploration of Creativity Techniques in Software Engineering in Training-Application-Feedback Cycle
    • Anna Bobkowska
    2019 Lecture Notes in Business Information Processing

    Creativity research has proposed about a hundred and fifty creativity techniques. The question is whether they can be applied in software engineering for creativity training or directing creativity in software projects. This paper aims at answering this question via a quasi-experiment conducted in Training-Application-Feedback cycle in which participants express their opinions about selected creativity techniques after training and an attempt to apply them in software-related context.

  • Extended investigation of performance-energy trade-offs under power capping in HPC environments
    • Adam Krzywaniak
    • Paweł Czarnul
    • Jerzy Proficz
    2019

    —In the paper we present investigation of performance-energy trade-offs under power capping using modern processors. The results are presented for systems targeted at both server and client markets and were collected from Intel Xeon E5 and Intel Xeon Phi server processors as well as from desktop and mobile Intel Core i7 processors. The results, when using power capping, show that we can find various interesting combinations of energy savings and performance drops as well as non-trivial minima of the energy-execution time product. We performed this analysis for a subset of NAS Parallel Benchmark applications: BT, CG, EP and FT and sizes of the computational problem (classes A, B, C, D). We can observe that the energy characteristics visualized by a prototype of our new tool EnergyProfiler do not depend on the size of a computational problem. Consequently, the proposed tool can potentially support quick energy/performance trade-off estimation for codes similar to the tested, well-recognized benchmarks.

  • Extremal thermal loading of a bifurcation pipe
    • Bartosz Kraszewski
    • Grzegorz Bzymek
    • Paweł Ziółkowski
    • Janusz Badur
    2019 Pełny tekst AIP Conference Proceedings

    The subject of considerations is a spherical bifurcation pipe of a live steam made of steel P91, which is an element of a block of coal-fired power plant working with a 18K370 turbine. As experience shows, it is a very sensitive element of the boiler pipelines. An extreme work scenario for such a block has been adopted, in which the turbine is shutting down to a warm state three times in 24 hours. This is an action dictated by new challenges in the field of electricity network regulation, caused by increasing share of renewable energy sources. A one-sided numerical thermal-FSI analysis was performed. The focus was on hoop stresses as the most significant for the bifurcation pipe durability. The daily runs of these stresses at three points of the thickness of the bifurcation pipe sphere have been presented. Mechanical stresses derived from pressure and thermal stresses derived from temperature changes have been isolated. It has been shown that depending on the thermal load, some areas of the cross section are compressed while adjacent ones are stretched and vice versa. Thus, the mechanical stresses can be reduced under thermal conditions by thermal stresses. It has been proven that the bifurcation pipe is able to withstand the given extreme loads with stresses more than twice smaller than the yield point at a given operating temperature.