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Ostatnie pozycje
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Identyfikacja wad powierzchni tocznej szyn za pomocą sygnału wibroakustycznego
- Roksana Licow
- Franciszek Tomaszewski
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.
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Impact of Boundary Conditions on Acoustic Excitation of EntropyPerturbations in a Bounded Volume of Newtonian Gas
- Anna Perelomova
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
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Impact of Cyclist Facility Availability at Work on the Number of Bike Commuters
- Romanika Okraszewska
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.
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Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
- Leszek Jarzębowicz
- Miroslav Gutten
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.
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Impact of high temperature drying process on beech wood containing tension wood
- Ivan Klement
- Tatiana Vilkovská
- Uhrín Miroslav
- Jacek Barański
- Aleksandra Konopka
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.
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Impact of polder flood plain of the Cisowska Struga on the transformation of flood waves between Gdynia and Rumia
- Michał Szydłowski
- Wojciech Szpakowski
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.
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Impact of probability distribution on the uncertainty of resistance measurement
- Stanisław Szczesny
- Anna Golijanek-Jędrzejczyk
- Dariusz Świsulski
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%.
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
- Mariusz Jaczewski
- Bohdan Dołżycki
- Jacek Alenowicz
- Piotr Jaskuła
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.
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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
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.
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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
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.
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Impact of the Artificial Strait in the Vistula Spit on the Hydrodynamics of the Vistula Lagoon (Baltic Sea)
- Michał Szydłowski
- Tomasz Kolerski
- Piotr Zima
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.
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IMPACT OF THE ORGANISATION OF MEGA SPORTING EVENTS ON SELECTED ELEMENTS OF THE TOURISM SECTOR
- Krystian Zawadzki
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.
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Implementation of Addition and Subtraction Operations in Multiple Precision Arithmetic
- Kamil Rudnicki
- Tomasz Stefański
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.
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Implementation of control system and tracking objects in a Quadcopter
- Siva Ariram
- Juha Roning
- Zdzisław Kowalczuk
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.
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Implementing Smart Virtual Product Development (SVPD) to Support Product Manufacturing
- Muhammad Ahmed
- Cesar Sanin
- Edward Szczerbicki
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.
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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
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.
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Improved Empirical Coefficients for Estimating Water Vapor Weighted Mean Temperature over Europe for GNSS Applications
- Zofia Baldysz
- Grzegorz Nykiel
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.
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Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
- Marek Krzaczek
- Jarosław Florczuk
- Andrzej Tejchman-Konarzewski
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.
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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
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.
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Improvement of ships seakeeping performance by application of the Full-scale CFD simulations – case study
- Karol Niklas
- Hanna Pruszko
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.
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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
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.
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Improvements to the two-phase sandwich method for calculating the melting points of pure metals
- Kamil Rybacki
- Valeriy Plechystyy
- Szymon Winczewski
- Jarosław Rybicki
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.
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Improving Accuracy of Contactless Respiratory Rate Estimation by Enhancing Thermal Sequences with Deep Neural Networks
- Alicja Kwaśniewska
- Jacek Rumiński
- Maciej Szankin
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.
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Improving SBR Performance Alongside with Cost Reduction through Optimizing Biological Processes and Dissolved Oxygen Concentration Trajectory
- Robert Piotrowski
- Aleksander Paul
- Mateusz Lewandowski
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.
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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
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.
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Impulse Impedance Measurements of Lightning Protection Earthings
- T. Horchue
- W. Tangtheerajaroonwong
- Stanisław Wojtas
- Marek Wołoszyk
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.
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In search of a common ground for the space sciences
- Edmund Wittbrodt
- Zdzisław Brodecki
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.
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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
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.
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In Situ Verification of Numerical Model of Water Hammer in Slurries
- Apoloniusz Kodura
- Katarzyna Weinerowska-Bords
- Wojciech Artichowicz
- Michal Kubrak
- Pawel Stefanek
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.
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Incorporating Iris, Fingerprint and Face Biometric for Fraud Prevention in e-Passports Using Fuzzy Vault
- Katarzyna Bobkowska
- Khaled Ahmed Nagati
- Marek Przyborski
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.
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Increasing K-Means Clustering Algorithm Effectivity for Using in Source Code Plagiarism Detection
- Patrik Hrkút
- Michal Ďuračík
- Miroslava Mikušová
- Mauro Callejas-cuervo
- Joanna Żukowska
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.
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Increasing the Seismic Resistance of Wood-frame Buildings by Applying PU Foam as Thermal Insulation
- Wojciech Migda
- Marcin Szczepański
- Robert Jankowski
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.
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In-depth characterization of icosahedral ordering in liquid copper
- Szymon Winczewski
- Jacek Dziedzic
- Jarosław Rybicki
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.
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Induction of chirality in 4,4'-azopyridine by halogen-bonding interaction with optically active ditopic donors
- Jan Alfuth
- Jarosław Chojnacki
- Tadeusz Połoński
- Teresa Olszewska
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.
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Influence of artificial thermal ageing on polyester-reinforced and polyvinyl chloride coated AF9032 technical fabric
- Paweł Kłosowski
- Krzysztof Żerdzicki
- Krzysztof Woznica
The presented work deals with the thermal ageing evaluation for polyester-reinforced and polyvinyl chloride coated fabrics. The architectural fabric AF9032 was exposed to artificial thermal ageing by subjecting the material samples to temperature levels of 80℃ and 90℃ for up to 12 weeks. The mechanical properties of the aged fabric have been separately described by the identified linear piecewise model (with assumption of the elastic behavior) and by the Bodner–Partom model (with assumption of the viscoplastic behavior). The evolution of the obtained parameter values for various ageing temperatures and over ageing periods have been approximated by linear functions achieving a good convergence. The simplified methodology of Arrhenius has been incorporated for the extrapolation of functions obtained for 90℃ and consequently used for ageing analysis. For the fill direction, the lines describing evolution of the mechanical parameters over ageing time coincide fully with the ultimate tensile strength and elongation at break and are parallel for the Bodner–Partom model parameters (R0,R1,m1,D1,m2,n) when comparing results for 80° and 90℃. For the warp direction, the obtained lines concerning mechanical properties and Bodner–Partom parameters exhibit different tendencies (increasing or decreasing) for both temperatures. Thus, the ageing evaluation according to the Arrhenius law has been confirmed by the obtained results only for the fill direction.
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Influence of cooling rate and additives on low-temperature properties of asphalt mixtures in the TSRST
- Marek Pszczoła
- Cezary Szydłowski
- Mariusz Jaczewski
The paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 C/h, 3 C/h, 5 C/h and 10 C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each factor stiffness moduli were back-calculated from the TSRST results and analysed. The greatest impact on the TSRST results had type of bitumen, followed by the cooling rate and additives. Application of longer fibres improved low-temperature properties of the asphalt mixtures.
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Influence of Different Biofuels on the Efficiency of Gas Turbine Cycles for Prosumer and Distributed Energy Power Plants
- Dariusz Mikielewicz
- Krzysztof Kosowski
- Karol Tucki
- Marian Piwowarski
- Robert Stępień
- Olga Orynycz
- Wojciech Włodarski
The efficiency of a gas turbine can be affected by the use of different biofuels usually with a relatively Lower Heating Value (LHV). The paper evaluates the impact of calorific value of fuel on turbine performance and analyzes the possibilities of optimizing turbine construction from the point of view of maximum efficiency for a particular fuel. The several variants of design of small power microturbines dedicated to various biofuels are analyzed. The calculations were carried out for: gas from biomass gasification (LHV = 4.4 MJ/kg), biogas (LHV = 17.5 MJ/kg) and methane (LHV = 50 MJ/kg). It is demonstrated that analyzed solution enables construction of several kW power microturbines that might be used on a local scale. Careful design of such devices allows for achieving high efficiency with appropriate choice of the turbine construction for specific fuel locally available. Such individually created generation systems might be applied in distributed generation systems assuring environmental profits.
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Influence of Fragment Size on the Time and Temperature of Ethylene Vinyl Acetate Lamination Decomposition in the Photovoltaic Module Recycling Process
- Anna Kuczyńska-Łażewska
- Ewa Klugmann-Radziemska
Photovoltaics is a commercially available and reliable technology with significant potential for long-term growth in nearly all global regions. Several research institutes and companies are working on recycling concepts for thin film modules and modules with crystalline cells. The establishment of recycling and reuse technologies appropriate and applicable to all photovoltaics (PV) modules is a key issue to be addressed as part of corporate social responsibility to safeguard the environment and to implement a fully material-circulated society without any waste. The copolymer ethylene-vinyl acetate (EVA) layer is a thermoplastic containing cross-linkable ethylene vinyl acetate, which is used to encapsulate the photovoltaic cells. The cells are laminated between films of EVA in a vacuum, under compression, and up to 150·°C. The encapsulant’s primary purpose is to bond or laminate the multiple layers of the module together. In the photovoltaic module recycling process, the second important step (after mechanical dismantling of the frame) is EVA lamination removal. In this study, different parameters of the thermal delamination method used during the recycling process were experimentally tested and compared, and the most ecological and economical one is proposed.
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Influence of High Temperature Oxidation on Hydrogen Absorption and Degradation of Zircaloy-2 and Zr 700 Alloys
- Andrzej Zieliński
- Anita Cymann
- Adrian Gumiński
- Anna Hernik
- Grzegorz Gajowiec
The present research was aimed at determining the effects of the oxide layers on hydrogen absorption, microstructure and mechanical properties of the Zircaloy- 2 and Zr 702 alloys. The oxidation was made at 350 °C, 700 °C and 900 °C for 10 to 30 min in laboratory air, followed by hydrogen cathodic charging for 72 h and annealing at 400 °C for 4 h. The slow strain rate tests were carried out on oxidized, charged and annealed specimens. The oxidation resulted in thick and cracked, more for Zr 702 alloy, layer. After oxidation at 350 °C, the appearance of hydrides in Zircaloy-2 and absence of hydrides in Zr 702 alloy were observed. After oxidation at high temperatures no current flow was noticed at applied voltage up to 5 V, and no hydrogen or hydrogen cracks. The observed effects were attributed to the phase structure of investigated alloys at low hydrogen content.
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INFLUENCE OF INLET GEOMETRY ON THE EFFICIENCY OF 1MW STEAM TURBINE
- Arkadiusz Koprowski
- Dominik Gotowski
- Romuald Rządkowski
- Ryszard Szczepanik
The process of the design of the 1MW steam turbine includes designing the stator and rotor blades, the steam turbine inlet and exit, the casing and the rotor. A turbine that operates at rotation speeds other than 3000 rpm requires a gear box and generator with complex electronic software. This paper analyses the efficiency of eight turbine variants, including seven inlet geometries and three stages of stator as well as an eight variant with one of the inlets, all three stages and an outlet.
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Influence of microwave treatment conditions of GTR on physico-mechanical and structural properties of NBR/NR/GTR composites
- J Canavate
- Xavier Colom
- Mohammad Saeb
- Marta Przybysz-Romatowska
- Łukasz Zedler
- Krzysztof Formela
The increasing amount of tires used in the industry induces the researchers to find alternatives to the recycling of the end-of-life tires. Several alternatives in order to application of ground tire rubber GTR include their incorporation as a filler in composites. The main issue in this approach is the lack of compatibility between GTR and polymer matrix. In order to solve this problem the devulcanization by microwaves has been proposed as an interesting approach in order to improve the subsequent crosslinking when the GTR is incorporated to an elastomeric matrix and subsequently co-vulcanizated. In this article a blend formed by natural rubber NR and nitrile butadiene rubber NBR has been proposed as a suitable matrix for composites including GTR. In order to improve the compatibility, the GTR was treated by microwaves prior to its application as semi-reinforcement in rubber matrix. The results indicate that the pretreatment of GTR by microwaves improves the cross-linking and co-vulcanization of used elastomers, what have a positive influence on the mechanical behaviour and microstructure of the NR/NBR/GTR composites evaluated by tensile tests, equilibrium swelling, Thermo Gravimetric Analysis (TGA), Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy (SEM).
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Influence of orientational disorder on the optical absorption properties in hybrid metal‐halide perovskite CH3NH3PbI3. A combined DFT/TD‐DFT and experimental study.
- Adam Miłosz
- Głowienka Damian
- Jędrzej Szmytkowski
- Galagan Yulia
- Julien Guthmuller
An experimental and theoretical investigation is reported to analyze the relation between the structural and absorption properties of CH3NH3PbI3 in the tetragonal phase. More than 3000 geometry optimizations were performed in order to reveal the structural disorder and to identify structures with the lowest energies. The electronic structure calculations provide an averaged band gap of 1.674 eV, which is in excellent agreement with the experimental value of about 1.6 eV. The simulations of the absorption spectrum for three representative structures with lowest energy reproduced the absorption shoulders observed in the experimental spectra. These shoulders are assigned to excitations having similar orbital characters and involving transitions between hybridized 6s(Pb)/5p(I) orbitals and 6p(Pb) orbitals. The geometries of the three structures were analyzed and the effects of the inorganic frame and the CH3NH3+ cations on the absorption properties were estimated. It was found that both changes in the inorganic frame and the CH3NH3+ cations orientations impact the absorption spectra, by modifying the transitions energies and intensities. This highlights the role of CH3NH3+ cation in influencing the absorption properties of CH3NH3PbI3 and demonstrates that CH3NH3+ cation is one of the key elements explaining the broad and nearly constant absorption spectrum in the visible range.
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Influence of Parameters of Laser Beam Welding on Structure of 2205 Duplex Stainless Steel
- Michał Landowski
Laser welding is used in modern industry, having many advantages comparing to traditional welding technologies. Nowadays, industry sectors such as shipbuilding, automotive and aviation can’t be imagined without laser processing technologies. Possibility of increase of welded joint properties, autogenous welding and high level of process automation makes the technology of laser welding perspective part of the industry. Physical multidimensional processes complexity requires a deeper understanding of the impact of laser welding parameters on the quality of welded joints for industrial implementation. The paper presents results of microstructure investigations of laser beam welded stainless steel under various welding parameters. Welded joints was achieved by Ytterbium fiber laser type without the use of the filler material. Material for test was 2205 ferritic-austenitic duplex stainless steel (DSS) plates with thickness of 8 mm in delivery condition. The objectives of this research was to investigate influence of laser welding parameters on weld geometry of buttwelded joints. Investigations of bead shape revealed correlation between laser beam focus position and weld penetration depth.
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Influence of Selected Saccharides on the Precipitation of Calcium-Vaterite Mixtures by the CO2 Bubbling Method
- Donata Konopacka-Łyskawa
- Natalia Czaplicka
- Barbara Kościelska
- Marcin Stanisław Łapiński
- Jacek Gębicki
Calcium carbonate is a compound existing in living organisms and produced for many biomedical applications. In this work, calcium carbonate was synthesized by a CO2 bubbling method using ammonia as a CO2 absorption promotor. Glucose, fructose, sucrose, and trehalose were added into the reaction mixture to modify characteristics of precipitated calcium carbonate particles. To determine the polymorphic form of produced calcium carbonate particles, Fourier transform infrared spectroscopy (FTIR-ATR) and X-ray diffraction (XRD) analysis were performed. Scanning electron microscopy (SEM) was used to estimate the size and shape of produced particles. Mixtures of vaterite and calcite were synthesized in all experiments. The percentage content of the vaterite in the samples depended on used additive. The highest concentration of vaterite (90%) was produced from a solution containing sucrose, while the lowest concentration (2%) was when fructose was added. Saccharides affected the rate of CO2 absorption, which resulted in a change in the precipitation rate and, therefore, the polymorphic composition of calcium carbonate obtained in the presence of saccharides was more varied.
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Influence of silver-core gold-shell nanoparticle parameters on the variation of surface-enhanced Raman spectra
- Maciej Wróbel
- Katarzyna Karpienko
- Marcin Marzejon
- Filip Sadura
- Soumik Siddhanta
- Ishan Barman
- Janusz Smulko
The detection of molecules by surface-enhanced Raman spectroscopy (SERS) is dependent on the nanomaterial used to induce the enhancement effect. This depends on a variety of parameters of the substrate such as the metal used for their creation, their shape, size and size distribution, concentration, as well as the parameters of the solution, such as packing of the nanoparticles, the complexity of the sample, the solvent, etc. It is most crucial, that the parameters are kept constant to provide uniformity of the enhancement. this is crucial for the development of SERS as a reliable and quantitative technique for bioanalysis. Here, we have developed the silver-core and gold-shell nanoparticles, to serve as the enhancement material. The fabrication phase involved constant concentrations of chemicals stability of the solution physical parameters like stirring and heating, and differed only in the perturbation of the reagents addition kinetics. These nanoparticles were investigated further with their ability to measure the solutions of 2-naphtalenethiol in DMSO, as model for testing the variability of the signal due to the enhancement and the kinetics of the nanoparticle-sample solution during a routine Raman measurement procedure. The results indicate vast difference in the preference of the 2-naphthalenethiol to come into contact with the nanoparticles and the partial enhancement of DMSO in most cases, with an almost complete by-pass of the solvent and direct detection of the 2-naphthalenethiol in one case. Moreover, the kinetics of the measurement solution, or its stability during measurement, is provided.
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Influence of soil–structure interaction on seismic pounding between steel frame buildings considering the effect of infill panels
- Hytham Elwardany
- Ayman Seleemah
- Robert Jankowski
- Saher El-Khoriby
The present research aims to study the influence of the soil-structure interaction (SSI) and existence or absence of masonry infill panels in steel frame structures on the earthquake-induced pounding-involved response of adjacent buildings. The study was further extended to compare the pounding-involved behavior versus the independent behavior of structures without collisions, focusing much on dynamic behavior of single frames. The effect of SSI was analyzed by assuming linear springs and dashpots at the foundation level. The infill panels were modeled using equivalent diagonal compression struts. The steel frames were assumed to have elastic-plastic behavior with 1% linear strain hardening. The dynamic contact approach was utilized to simulate pounding between the adjacent buildings. Nonlinear finite element analysis was performed for two adjacent multi-story structures with four different configurations representing cases that can exist in reality. The seismic response of the studied cases generally emphasized that ignoring the soil flexibility and/or the contribution of the infill panels may significantly alter the response of adjacent structures. This may result in a false expectation of the seismic behavior of buildings exposed to structural pounding under earthquake excitation.
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Influence of steam cooking on pro-health properties of Small and Large variety of Momordica charantia
- Martyna Lubinska-Szczygeł
- Anna Różańska
- Jacek Namieśnik
- Tomasz Dymerski
- Arkadiusz Szterk
- Patraporn Luksirikul
- Suchada Vearasilp
- Elena Katrich
- Shela Gorinstein
Steam cooking is one of the most common preparations of Momordicacharantia dishes. This method improved the tastiness of the fruits but at the same time, some changes occurred in the volatile and non-volatile parts of their food matrices. In this study, for the first time these properties were correlated with the found substances affecting the bioactivity of this fruit. Two varieties of Momordicacharantia were analysed and compared. It was possible to differentiate both types of fruits using two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC-TOF-MS) as well as to assess botanical and geographical origin. In the case of volatiles, 212 chemical compounds were tentatively identified, which can be classified into seven chemical classes, such as aldehydes, alcohols, esters, ketones, terpenes, hydrocarbons. Furthermore, 16 of them were quantified and calculated in terms of OAV and ROC values. Bioactive substances (polyphenols, flavonoids, tannins and flava- nols) and the values of antioxidant capacities by four radical scavenging assays (DPPH, CUPRAC FRAP, ABTS) were determined and compared in water and methanol extracts of Chinese and Indian varieties. It was proven that steam cooked Chinese variety has greater value due to its flavour than Indian variety and consists more volatile, non-volatile and bioactive constituents with high antioxidant effect. The binding properties of poly- phenols to HSA were relatively high in comparison with other plants. A strong positive correlation of binding properties and bioactivity of Momordicacharantia was estimated. One of the volatiles, namely citronellol, has key importance in respect of antidiabetic effect of Momordica charantia Chinese variety. This study indicates pro- health preponderance of Chinese variety over Indian variety and confirms that steam cooking is in lines with the canons of safe food preparation.
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Influence of steel brackets supporting crane runway girders structure on the stress distribution in the brackets
- Natalia Korcz-Konkol
- Piotr Iwicki
- Elżbieta Urbańska-Galewska
The paper presents a numerical analysis of steel brackets supporting a double-span crane runway girders. The purpose of the study was to assess the new structural solution based on the stress distribution in the brackets. In order to simplify the connection, the bottom flange of the crane runway girder is based directly on the upper flange of the bracket. As a result, the support reaction is no longer applied in the plane of the bracket web, but it is carried as ununiform pressure. Known analytical methods are not sufficient to assess the level of the bracket material effort due to the mechanism of the forces transmission. That is why the FE analysis was performed. Twisting of the bracket caused by eccentric load (in addition to the biaxial bending) was observed. What is more it occurred that transverse stiffeners in the bracket structure generate high stress.
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Influence of Storage Time and Temperature on the Toxicity, Endocrine Potential, and Migration of Epoxy Resin Precursors in Extracts of Food Packaging Materials
- Błażej Kudłak
- Natalia Jatkowska
- Paweł Kubica
- Galina Yotova
- Tsakovski Stefan
The aim of the present study was to establish a standard methodology for the extraction of epoxy resin precursors from several types of food packages (cans, multi-layered composite material, and cups) with selected simulation media (distilled water, 5% ethanol, 3% dimethyl sulfoxide, 5% acetic acid, artificial saliva) at different extraction times and temperatures (factors). Biological analyses were conducted to determine the acute toxicity levels of the extracts (with Vibrio fischeri bacteria) and their endocrine potential (with Saccharomyces cerevisiae yeasts). In parallel, liquid chromatography-tandem mass spectrometry was performed to determine levels of bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (mixture of isomers, BFDGE), ring novolac glycidyl ether (3-ring NOGE), and their derivatives. The variation induced by the different experimental factors was statistically evaluated with analysis of variance simultaneous component analysis (ASCA). Our findings demonstrate the value of using a holistic approach to best partition the effects contributing to the end points of these assessments, and offer further guidance for adoptingsuch a methodology, thus being a broadly useful reference for understanding the phenomena related to the impacts of food packaging materials on quality for long- and short-term storage, while offering a general method for analysis.