2015 - Repozytorium publikacji - Politechnika Gdańska

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ENHANCED EVAPORATION OF THE DROPLETS OF CONDENSATE IN THE ASYMMETRICAL SHOCK WAVE ZONE
- Sebastian Kornet
- Janusz Badur
2015 Transactions of the Institute of Fluid-Flow Machinery
In the low-pressure part of steam turbine, the state path usually crosses the saturation line in penultimate stages [4,5]. The formation and evolution of these droplets lower the performance of the wet stages of the turbines, and their effects on the efficiency are collectively known as wetness losses [4]. Nowadays, due to work of steam turbines at partial load, process of homogeneous and heterogeneous condensation still is current. Thermomechanical aspects of the nucleation, growth and interaction of water droplets in the steam turbine of large output are still poorly understood [1,2]. The flow in the low-pressure part of steam turbine is complicated and still requires thorough experimental and numerical analysis. The present work is concerned with investigation into coupled phenomena occurring in the supersonic section of the de Laval nozzle, characterized by the presence of shock the flow of condensing steam. The numerical simulations results were compared with the experiment carried out by Dykas et al. in 2013 on the half arc nozzles [3]. The present work includes simulations results of oscillation frequency of the shock wave and conditions for the enhancement evaporation of condensate on the asymmetrical shock wave. Novelty of our approach lies on modeling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase
Enhanced photoelectrochemical and photocatalytic performance of iodine-doped titania nanotube arrays
- K. Siuzdak
- Mariusz Szkoda
- Mirek Sawczak
- Anna Lisowska-Oleksiak
- Jakub Karczewski
- Jacek Ryl
2015 RSC Advances
The paper discusses the synthesis and performance of iodine doped titania nanotube arrays exhibited under irradiation. The doping procedure was performed as an additional, electrochemical process carried out after formation of nanotube arrays via anodization of Ti substrate. The optical and structural properties were characterized using Raman, UV-vis, photoluminescence and X-ray photoelectron spectroscopy. The surface morphology and cross-section studies performed by means of the scanning electron microscopy show that the ordered tubular architecture is not influenced by any doping methods. However, iodine doping causes a reduction of bandgap energy and photoluminescence intensity. The nanotubular TiO2 electrodes have been monitored by electrochemical (using cyclic voltammetry and electrochemical impedance spectroscopy) and in-situ UV-vis spectroelectrochemical measurements in contact with an aqueous electrolyte. Collected results show significant differences in electrochemical activity between pure and doped titania exhibited as i.e. change of Mott-Schottky relation or shift in onset potential when a decrease in reflectance is initiated. The photocurrent density reached 155.2 and 142.2 µA cm-2 for iodine doped materials when KI and HIO4 were used as iodine precursors whereas only 25.6 µA cm-2 was registered for pure titania nanotubes under UV-vis illumination. Moreover, doped samples are far more efficient at the photodegradation progress than undoped material leading to decomposition of over 70% of methylene blue used as model organic pollution. Reported studies demonstrate for the first time the detailed optical, electrochemical and photoelectrochemical studies of iodine doped nanotube arrays.
Enhanced voice user interface employing spatial filtration of signals from acoustic vector sensor
- Kuba Łopatka
- Józef Kotus
- Piotr Bratoszewski
- Paweł Spaleniak
- Marcin Szykulski
- Andrzej Czyżewski
2015
Spatial filtration of sound is introduced to enhance speech recognition accuracy in noisy conditions. An acoustic vector sensor (AVS) is employed. The signals from the AVS probe are processed in order to attenuate the surrounding noise. As a result the signal to noise ratio is increased. An experiment is featured in which speech signals are disturbed by babble noise. The signals before and after spatial filtration are processed by an automatic speech recognition (ASR) engine. It is shown that employing spatial filtration of signals from the AVS probe leads to a significant reduction in word error rate (WER) for a dictionary of 184 words.
Enhancing the Seismic Resistance of Columns by GFRP Confinement Using Flexible Adhesive-Experimental Study
- Natalia Lasowicz
- Arkadiusz Kwiecień
- Robert Jankowski
2015 Key Engineering Materials
In this paper, the results of two experiments, focused on testing the effectiveness of a method of enhancing the seismic (dynamic) resistance of masonry columns with the use of flexible polymer adhesive, are shown. The first experiment was devoted to investigate the damping properties of a polymer working between two stiff layers, whereas the aim of the second one was to verify if the identified damping properties of the polymer can improve the dynamic behaviour of short masonry columns (prisms) strengthened by confinement made of GFRP grid bonded by the polymer adhesive. The results of the first stage of experimental investigation indicate that bonding two stiff elements with the analyzed polymer adhesive leads to the significant increase in overall damping properties. The results of the second experiment show that the GFRP grid confinement with flexible polymer adhesive is more effective than stiff epoxy and mineral adhesives.
Entanglement and Nonlocality are Inequivalent for Any Number of Parties
- R. Augusiak
- Maciej Demianowicz
- J. Tura
- A. Acín
2015 PHYSICAL REVIEW LETTERS
Understanding the relation between nonlocality and entanglement is one of the fundamental problems in quantum physics. In the bipartite case, it is known that these two phenomena are inequivalent, as there exist entangled states of two parties that do not violate any Bell inequality. However, except for a single example of an entangled three-qubit state that has a local model, almost nothing is known about such a relation in multipartite systems. We provide a general construction of genuinely multipartite entangled states that do not display genuinely multipartite nonlocality, thus proving that entanglement and nonlocality are inequivalent for any number of parties.
Enthalpies of formation of rare earth niobates, RE3NbO7
- Aleksandra Dorota Mielewczyk-Gryń
- Alexandra Navrotsky
2015 AMERICAN MINERALOGIST
High-temperature oxide melt solution calorimetry was used to investigate energetics of a series of rare earth niobates RE3NbO7. All of investigated compounds were found to be stable in enthalpy in respect to their oxides. The enthalpy of formation from oxides becomes more exothermic as the size of the RE cation increases, a trend seen previously in other RE compounds including pyrochlores, perovskites, and phosphates. For smaller RE cations the enthalpy of exchange of RE between niobates and titanates is close to zero, whereas larger RE are energetically favored in the titanate pyrochlores. Implications of the results from the geochemical and material engineering points of view are discussed.
Entrepreneurial Education and Attitude among Young Generations in a Gender perspective: the Case of Polish Education System
- Magdalena Popowska
2015 Erenet Profile
This article is an attempt to analyze the impact of entrepreneurship education on entrepreneurial attitudes and intentions of young people: male and female students of Polish high schools and universities. The author makes an effort to verify the impact of the exposure to the business education and entrepreneurs on the decision to start-up. Special emphasis will be placed on the gender differences when discussing a respective factors’ impact and on the country context, especially when analyzing the influence of perception of entrepreneurs by young generation of respondents. The paper will provide also a number of tips and guidelines for decision-makers in the wider area of entrepreneurship education, and thus ensuring proper orientation of policy support in this largely underestimated field of education.
Entropic Measures of Complexity of Short-Term Dynamics of Nocturnal Heartbeats in an Aging Population
- Danuta Makowiec
- Agnieszka Kaczkowska
- Dorota Wejer
- Marta Żarczyńska-Buchowiecka
- Zbigniew R. Struzik
2015 Pełny tekst ENTROPY
Two entropy-based approaches are investigated to study patterns describing differences in time intervals between consecutive heartbeats. The first method explores matrices arising from networks of transitions constructed following events represented by a time series. The second method considers distributions of ordinal patterns of length three, whereby patterns with repeated values are counted as different patterns. Both methods provide estimators of dynamical aspects of short-term heartbeat signals obtained from nocturnal Holter electrocardiogram (ECG) recordings of healthy people of different ages and genders. The deceleration capacity, arising from the adjacency matrix of the network, and the entropy rate, resulting from the transition matrix of the network, are also calculated, and both significantly decay with aging. As people age, the permutation entropy grows, due to the increase in patterns with repeated values. All of these estimators describe in a consistent way changes in the beat-to-beat heart period dynamics caused by aging. An overall slowing down of heart period changes is observed, and an increase of permutation entropy results from the progressive increase of patterns with repeated values. This result points to the sympathetic drive becoming dominant in cardiac regulation of nocturnal heart rate with age.
Entropy Measures in the Assessment of Heart Rate Variability in Patients with Cardiodepressive Vasovagal Syncope
- Beata Graff
- Grzegorz Graff
- Danuta Makowiec
- Agnieszka Kaczkowska
- Dorota Wejer
- Szymon Budrejko
- Dariusz Kozłowski
- Krzysztof Narkiewicz
2015 Pełny tekst ENTROPY
Sample entropy (SampEn) was reported to be useful in the assessment of the complexity of heart rate dynamics. Permutation entropy (PermEn) is a new measure based on the concept of order and was previously shown to be accurate for short, non-stationary datasets. The aim of the present study is to assess if SampEn and PermEn obtained from baseline recordings might differentiate patients with various outcomes of the head-up tilt test (HUTT). Time-domain heart rate variability (HRV) indices and several nonlinear parameters were calculated using 500 RR interval-long ECG recordings done before tilting in patients with a history suggesting vasovagal syncope. Groups of patients with so-called cardiodepressive vasovagal syncope (VVS_2) during HUTT and patients who did not faint during the test were compared. Two types of HUT tests were analyzed: with spontaneous (SB) or controlled breathing (CB). In our study, SampEn was higher in VVS_2 patients during SB, and PermEn was higher in VVS_2 patients during CB. Irrespective of the type of breathing during the test, SampEn and PermEn were similar in patients with the same type of reaction during HUTT. The use of several entropy-based parameters seems to be useful in HRV assessment in patients with vasovagal fainting.
Environmentally Oriented Models and Methods for the Evaluation of Drug x Drug Interaction Effects
- Monika Wieczerzak
- Błażej Kudłak
- Jacek Namieśnik
2015 CRITICAL REVIEWS IN ANALYTICAL CHEMISTRY
This detailed review compares known and widely used methods for drug interaction estimation, some of which now have historical significance. Pharmaceutical application has been noted as far back as several thousand years ago. Relatively late in the 20th century, however, researchers became aware that their fate and metabolism, which still remain a great challenge for environmental analysts and risk assessors. For the patient’s well-being, treatment based on the mixing of drugs has to be effective and should not cause any side effects (or side effects should not have a significant impact on health and mortality). Therefore, it is important to carefully examine drugs both individually and in combinations. It should be also stated that application form/way of entering the living organism is of great importance as well as the age and the place in the trophic system of the organism in order to eliminate harmful dosages in the case of infants’ accidental intoxication.
ePBL – czyli nauka poprzez realizację projektu w środowisku wirtualnym
- Anita Maria Dąbrowicz-Tlałka
2015 Pismo PG
Kształcenie inżynierów stanowi niezwykle istotny element systemu edukacyjnego każdego nowoczesnego państwa, ponieważ to właśnie dobrze przygotowana kadra inżynierska decyduje o tempie rozwoju i poziomie infrastruktury danego kraju. Wykorzystanie najnowszych technologii w procesie edukacyjnym jest naturalną konsekwencją „informatyzacji” życia. Pokolenia dorastające w świecie wszechobecnych komputerów, urządzeń mobilnych i cyfrowej komunikacji wymuszają modernizację modeli kształcenia. Jedną z nowszych metod kształcenia jest Problem-Based Learning (PBL; nauczanie poprzez rozwiązywanie problemów) i ściśle z nim związany Project-Based Learning (kształcenie oparte na projektach). Nie jest to prosta metoda, ponieważ wiedza, jaką zdobywają studenci, jest ukryta w zadaniu, a cele kształcenia są realizowane podczas prac nad jego rozwiązaniem. Jeżeli kształcenie oparte na projekcie ma odbywać się zdalnie, wtedy przy wyborze wirtualnego środowiska pracy zespołowej należy uwzględnić metodykę i specyfikę prowadzonych zajęć. Technologia skutecznie zdominowała również sferę „umiejętności miękkich”, jakich muszą nabyć absolwenci uczelni wyższych i dlatego pamiętać należy, że zmiany w zakresie kształcenia na odległość i stosowanych w nim technologii też są olbrzymie. Ostatnio wiele się mówi o fenomenie Learning Record Store (LRS) i powiązanego z nim nowego standardu Tin Can API (nazywanego również xAPI). Pozwala to m.in. na budowanie systemu, który pokazuje zdobywane przez studenta umiejętności, co może mieć wielkie znaczenie na rynku pracy czy przy podejmowaniu decyzji o profilu dalszej edukacji.
Epigenetyczne i transkryptomiczne podstawy potencjału regeneracyjnego ssaków. Badania na modelach skóry płodowej i dorosłej myszy MRL/MpJ
- Justyna Podolak-Popinigis
2015
Regeneracja jest to zdolność do odbudowy uszkodzonych lub utraconych tkanek, kończyn oraz narządów. Efektywne procesy regeneracji obserwowane są u prymitywnych kręgowców, u których mogą przejawiać się w tak spektakularnych zjawiskach jak odtworzenie całych kończyn po ich amputacji. U wyższych kręgowców zdolności regeneracyjne są znacznie bardziej ograniczone. Rozwój metod umożliwiających badanie globalnych profili ekspresji i metylacji genów pozwala na nowe spojrzenie na problem regeneracji u ssaków. W niniejszej pracy skupiono się na charakterystyce molekularnych podstaw potencjału regeneracyjnego ssaków w oparciu o dwa modele charakteryzujące się podwyższoną odpowiedzią regeneracyjną: mysz MRL/MpJ oraz skóra piętnastodniowych embrionów (E15) myszy C57BL/6J. Mysz MRL/MpJ i skóra płodowa są ważnymi modelami badawczymi w dziedzinie regeneracji. Mysz MRL/MpJ wzbudza zainteresowanie z uwagi na podwyższoną odpowiedź regeneracyjną obserwowaną w różnych tkankach u dorosłego ssaka, natomiast skóra płodowa ze względu na zdolność do idealnego bezbliznowego gojenia ran występującą do początku trzeciego trymestru ciąży. Mysz MRL/MpJ, to szczep wsobny, który posiada szereg charakterystycznych nietypowych cech genetycznych podczas gdy bezbliznowe gojenie ran skóry płodu obserwuje się u różnych ssaków. Cechą wspólną myszy MRL/MpJ oraz skóry grzbietowej płodów w dniu embrionalnym 15 była podwyższona ekspresja genów homeotycznych oraz obniżona odpowiedź układu immunologicznego. Wskazuje to na kluczową rolę tych dwóch czynników w odpowiedzi regeneracyjnej. Podsumowując, wyniki moich prac badawczych poszerzają dotychczasową wiedzę o molekularnych podstawach regeneracji ssaków. Efektem tych badań jest uzyskanie po raz pierwszy w świecie globalnych profili metylacji genów w skórze grzbietowej myszy na różnych etapach rozwoju oraz unikalna porównawcza analiza transkryptomiczna wykonana dla pięciu różnych tkanek myszy MRL/MpJ i dwóch szczepów kontrolnych. W szczególności, rezultaty powyższych badań dostarczają dowodów na epigenetyczne uwarunkowania zdolności do bezbliznowego gojenia ran skóry płodowej oraz wskazują szlak metabolizmu retinolu jako potencjalny cel do farmakologicznej stymulacji regeneracji u dorosłych ssaków.
Equitable and semi-equitable coloring of cubic graphs and its application in batch scheduling
- Hanna Furmańczyk
- Marek Kubale
2015 Pełny tekst Archives of Control Sciences
In the paper we consider the problems of equitable and semi-equitable coloring of vertices of cubic graphs. We show that in contrast to the equitable coloring, which is easy, the problem of semi-equitable coloring is NP- complete within a broad spectrum of graph parameters. This affects the complexity of batch scheduling of unit-length jobs with cubic incompatibility graph on three uniform processors to minimize the makespan
Equivalence scales based on stochastic indifference criterion : the case of Poland
- Stanisław Kot
2015 PRZEGLĄD STATYSTYCZNY
Artykuł przedstawia koncepcję stochastycznych skał ekwiwalentności (SES), która bazuje na kryterium stochastycznej indyferencji. SES jest dowolną funkcją, która transformuje rozkład wydatków określonej grupy gospodarstw domowych w taki sposób, że wynikowy rozkład jest stochastycznie indyferentny wobec rozkładu wydatków grupy gospodarstw odniesienia. Kryterium stochastycznej indyferencji jest także wykorzystane dla opracowania metody estymacji SES. Oszacowano nieparametryczne i parametryczne SES na podstawie Polskich Budżetów Gospodarstw Domowych za lata 2005-2010.
Ergonomia w przychodniach z zespołami zaawansowanej diagnostyki obrazowej
- Agnieszka Gębczyńska-Janowicz
- Rafał Janowicz
2015
Placówki użyteczności publicznej prowadzące działalność medyczną w zakresie usług leczniczych i diagnostycznych są obiektami, których architektura kreowana jest pod silnym wpływem wymagań higieniczno sanitarnych oraz wytycznych technologii wynikającej z charakteru świadczonych usług. Ergonomia pełni tu bardzo istotną rolę, ponieważ wspiera technologie medyczne w zapewnieniu bezpieczeństwa użytkownikom- pacjentom i personelowi medycznemu.Artykuł opisuje zależności pomiędzy architekturą, technologią i ergonomią zachodzące w przestrzennym rozwoju współczesnych, polskich przychodni.
Ergonomiczne aspekty bezpieczeństwa w architekturze
- Rafał Janowicz
- Agnieszka Gębczyńska-Janowicz
2015
Jednym z podstawowych zadań architektury jako sztuki organizacji przestrzeni jest zapewnienie bezpieczeństwa człowiekowi w jego środowisku zamieszkania, pracy i wypoczynku. Planowanie budynków związane jest odpowiedzialnością za przyszłe, prawidłowe ich użytkowanie. W procesie projektowym należy przewidzieć wszystkie możliwe zagrożenia, jakie mogą wystąpić w wyniku eksploatacji. W tym wypadku istotna jest najszersza ocena zagrożeń, które mogą mieć miejsce w budynku, a następnie propozycja rozwiązań przestrzennych i technicznych, które nieszczęśliwym wypadkom mogą zapobiegać lub zminimalizować ich skutki. Przepisy dedykowane procesom budowlanym i projektowym z jednej strony poprawiają sytuację, z drugiej poprzez możliwości szerokiego pola ich interpretacji powodują niejasną sytuację podczas realizacji obiektów. W artykule przedstawione zostały aspekty niekorzystnego oddziaływania zbyt lakonicznych wykładni lub sprzecznych wytycznych umieszczonych w różnych aktach polskiego prawodawstwa.
Essential Oils, Silver Nanoparticles and Propolis as Alternative Agents Against Fluconazole Resistant Candida albicans, Candida glabrata and Candida krusei Clinical Isolates
- Piotr Szweda
- Katarzyna Magdalena Gucwa
- Ewelina Kurzyk
- Ewa Romanowska
- Katarzyna Dzierżanowska-Fangrat
- Anna Zielińska-Jurek
- Piotr Kuś
- Sławomir Milewski
2015 INDIAN JOURNAL OF MICROBIOLOGY
Development of effective and safe therapeutic treatment of fungal infections remains one of the major challenge for modern medicine. The aim of presented investigation was to analyze the in vitro antifungal activity of selected essential oils, ethanolic extracts of propolis and silver nanoparticles dropped on TiO2 against azole-resistant C. albicans (n = 20), C. glabrata (n = 14) and C. krusei (n = 10) clinical isolates. Among tested essential oils, the highest activity has definitely been found in the case of the oil isolated from the bark of Cinnamomum cassia, with MIC and MFC values for all tested strains in the range of 0.0006–0.0097 % (v/v) and 0.0012–0.019 % (v/v), respectively. High activity was also observed for the Lemon, Basil, Thyme, Geranium and Clove (from buds) essential oils. Significant differences in fungicidal activity have been observed in the case of four tested propolis samples. Only one of them revealed high activity, with MFC values in the range from 0.156 to 1.25 % (v/v). Satisfactory fungicidal activity, against C. albicans and C. glabrata isolates, was also observed in the case of silver nanoparticles, however C. krusei isolates were mostly resistant. We also revealed that constituents of most of essential oils and propolis as well as silver nanoparticles are not substrates for drug transporters, which belong to the most important factors affecting resistance of Candida spp. clinical isolates to many of conventional antimycotics. To conclude, the results of our investigation revealed that essential oils, propolis and silver nanoparticles represent high potential for controlling and prevention candidiasis.
Estimating the Average Speed of Public Transport Vehicles Based on Traffic Control System Data
- Jacek Oskarbski
- Krystian Birr
- Michał Miszewski
- Karol Żarski
2015
Intelligent Transport Systems are a valuable source of traffic information, covering both private and public vehicles. The main problem, however, is that very few studies are conducted to determine the speed of buses, trams and trolleys in urban networks in relation to traffic conditions. The paper investigates how ITS systems data could be used to model the speed of Public Transport vehicles. This is now possible thanks to the implementation of TRISTAR, an Integrated Traffic Management System covering the Tri - City (Gdansk, Sopot, Gdynia). The objective of the analysis is to develop a method for modelling Public Transport vehicle speed. To that end data from TRISTAR subsystems were used. The paper explains how various data can be collected, used and combined to develop speed models. The results of analyses and a proposed speed model for Gdynia's Public Transport vehicles are presented. This is to be further verified by applying the proposed method in another city or other cities. The speed model can also be used for updating existing public transport timetables. It is also possible to use the speeds for calibrating macroscopic simulation models.
Estimating the Impact of Inflow on the Chemistry of Two Different Caldera Type Lakes Located on the Bali Island (Indonesia)
- Żaneta Polkowska
- Lidia Wolska
- Leszek Łęczyński
- Marek Ruman
- Sara Lehmann-Konera
- Katarzyna Kozak
- Magdalena Matysik
- Damian Absalon
2015 Pełny tekst Water
This paper is a preliminary attempt to assess the composition of pollutants in two different caldera lakes situated in the Indonesian Archipelago: Batur and Bratan. Both lakes are characterized by largely different physico-chemical regimes; Batur Lake is located in an area that is currently volcanically active, unlike Bratan Lake. The latter is much smaller and shallower than Batur Lake. The concentration of pollutants in the Indonesian equatorial lakes is largely unknown, and the impact of both biological and geothermal processes on their distribution requires attention. This study shows that the concentrations of cations (Na+, K+ , Mg2+, Ca2+), anions (SO42−, F−, Cl−, Br−) and trace elements (Li, B, Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sn, Cs, Ba, Pb, U, Be, Ag, Sb, Tl, Bi) differ greatly between both lakes. Most chemical parameters determined in volcanically influenced Batur Lake were tens to hundreds times higher than in Bratan Lake, and in the case of trace metals, the ratios of the two lakes’ concentrations reached several hundreds. This study also compared the composition and concentration levels of organic compounds in both lakes, such as fatty acids, halocarbons and esters. On the other hand, the content of organic chemicals in the lakes also results from biological activity by phytoplankton, zooplankton and bacteria.
Estimation of the uncertainty of the AC/AC transducer output voltage
- Ariel Dzwonkowski
- Anna Golijanek-Jędrzejczyk
2015 Pełny tekst Przegląd Elektrotechniczny
The paper presents a methodology for estimating uncertainty of voltage transducers processing function, on the example of CYVS411D07 voltage transducers. The analysis was conducted using the method based on the GUM Guide propagation of uncertainty law and the determination of the coverage factor based on the effective number of degrees of freedom (t-Student distribution). The paper also presents example evaluation results of measured voltage uncertainty for a few selected voltage and frequency values.