2014 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2014

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Heat transfer in plate heat exchanger channels: experimental validation of selected correlation equations
- Janusz Cieśliński
- Artur Fiuk
- Krzysztof Typiński
- Bartłomiej Siemieńczuk
2014
This study is focused on experimental investigation of selected type of brazed plate heat exchanger. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. The main aim of the paper was to experimentally check ability of several correlations published in the literature to predict heat transfer coefficients by comparison experimentally obtained data with appropriate predictions. The results obtained revealed that Hausen and Dittus-Bölter correlations underestimated heat transfer coefficient for the tested PHEx by an order of magnitude. The Aspen Plate code overestimated heat transfer coefficient by about 50%, while Muley-Manglik correlation overestimated it from 1% to 25%, dependent on the value of Reynolds number and hot or cold liquid side.
Hedging with derivatives - Case of Polish market
- Radosław Ślosarski
- Bruno Schivinski
2014
This paper attempts to show the ways of reaching the competitive advantage by hedging with derivatives in Poland. It shows the results of investigation of 50 Polish companies and comparison to the situation in high developed countries. Through broad review of relevant literature, the authors presented the correlation between hedging and competitive advantage. Moreover, paper shows the reasons, of differences between Poland and United Kingdom at the presented topic.
Henryk Żółtowski - mostowiec
- Krzysztof Żółtowski
2014
W pracy przedstawiono sylwetkę wybitnego projektanta Henryka Żółtowskiego przez pryzmat jego dokonań. Zamieszczono opisy autorskich projektów i patentów stosowanych powszechnie w praktyce budowlanej
Hertzian Crack Propagation in Ceramic Rolling Elements
- Waldemar Karaszewski
2014 Key Engineering Materials
The properties of ceramics are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such crack are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack front are analyzed using boundary element model.
Hierarchia czynników wpływu w diagnostyce komponentów stalowych metodą statycznego pola rozproszonego
- Marek Augustyniak
- Zbigniew Usarek
- Bolesław Augustyniak
2014 Energetyka, problemy energetyki i gospodarki paliwowo - energetycznej
Wśród technik badań nieniszczących obiektów stalowych (NDT) szczególną rolę pełnią techniki elektromagnetyczne, jako relatywnie tanie, czyste, szybkie i adaptowalne. Mają one jednak istotne ograniczenia, o których wydają się zapominać praktycy promujący tzw. metodę magnetycznej pamięci metali (ang. magnetic metal memory, MMM). Szczególnie dyskusyjna jest postulowana przez nich możliwość ilościowej korelacji charakterystyk pola rozproszonego przy powierzchni komponentu z lokalnym stanem naprężeń. W niniejszej pracy dokonana jest krytyczna ocena i gruntowna reinterpretacja już opublikowanych wyników [5]. Własne pomiary i modelowanie magnetyczne Metodą Elementów Skończonych prowadzą do wniosku, że określony lokalny gradient pola magnetycznego wynika z kombinacji czterech czynników: mikrostruktury, namagnesowania resztkowego, geometrii obiektu oraz stanu naprężeń. W rozważanym przypadku ostatni z wymienionych czynników, choć najistotniejszy inżyniersko, wpływa najsłabiej na charakterystykę pola rozproszonego. W konsekwencji nie ma możliwości utworzenia funkcji odwrotnej służącej jednoznacznemu wyznaczaniu lokalnych naprężeń według metodyki MMM.
High frequency oscillations are associated with cognitive processing in human recognition memory
- Michał Tomasz Kucewicz
- Jan Cymbalnik
- Joseph Matsumoto
- Benjamin H. Brinkmann
- Mark R. Bower
- Vincent Vasoli
- Vladimir Sulc
- Fred Meyer
- W.r. Marsh
- S. M. Stead
- Gregory A. Worrell
2014 Pełny tekst Brain: A Journal of Neurology
High frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30-100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans demonstrate that physiological oscillations extend beyond the gamma frequency range, but their function in human cognitive processing has not been fully elucidated. Here we investigate high frequency oscillations spanning the high gamma (50-125 Hz), ripple (125-250 Hz) and fast ripple (250-500 Hz) frequency bands using intracranial recordings from 12 patients (five males and seven females, age 21-63 years) during memory encoding and recall of a series of affectively charged images. Presentation of the images induced high frequency oscillations in all three studied bands within the primary visual, limbic and higher order cortical regions in a sequence consistent with the visual processing stream. These induced oscillations were detected on individual electrodes localized in the amygdala, hippocampus and specific neocortical areas, revealing discrete oscillations of characteristic frequency, duration and latency from image presentation. Memory encoding and recall significantly modulated the number of induced high gamma, ripple and fast ripple detections in the studied structures, which was greater in the primary sensory areas during the encoding (Wilcoxon rank sum test, P = 0.002) and in the higher-order cortical association areas during the recall (Wilcoxon rank sum test, P = 0.001) of memorized images. Furthermore, the induced high gamma, ripple and fast ripple responses discriminated the encoded and the affectively charged images. In summary, our results show that high frequency oscillations, spanning a wide range of frequencies, are associated with memory processing and generated along distributed cortical and limbic brain regions. These findings support an important role for fast network synchronization in human cognition and extend our understanding of normal physiological brain activity during memory processing
High order of nongeminate recombination in organic bulk heterojunction solar cells
- Jędrzej Szmytkowski
2014 SEMICONDUCTOR SCIENCE AND TECHNOLOGY
We analyze high order of nongeminate recombination in organic donor–acceptor bulk heterojunction solar cells. The model of recombination where an exciton annihilates on an electron–hole Langevin bound pair near donor–acceptor interface has been applied in our studies. We obtained satisfactory agreement between experimental results and theoretical calculations for the concentration dependences of several parameters characterizing photovoltaic cells, such as the mobility of charge carriers, the recombination coefficient and the recombination time. The influence of carriers from deep states on the mobility has been taken into account.
High quality academic teacher of 21st century - Polish students' perspective
- Małgorzata Wiśniewska
- Piotr Grudowski
2014
The aim of the study is to determine the characteristics of the academic teacher quality level from the perspective of Polish universities students’ in 21st century.
High Speed Milling vibration surveillance with optimal spindle speed based on optimal speeds map
- Krzysztof Jan Kaliński
- Marek Galewski
- Michał Mazur
2014 Key Engineering Materials
The paper presents the method of the surveillance of the self-excited chatter vibration. At first, the workpiece modal parameters are estimated based on experimental data which leads to verification of computational model. Then, for selected surface points optimal spindle speeds are calculated. By considering sufficient amount of points it is possible to build a map of optimal spindle speeds. Experimental results show that this map may be used effectively for eliminating chatter in case of the process of ball end milling of a curved flexible detail.
High-Speed Serial Embedded Deterministic Test for System-on-Chip Designs
- Grzegorz Mrugalski
- Nilanjan Mukherejee
- Artur Pogiel
- Janusz Rajski
- Maciej Trawka
- Jerzy Tyszer
2014
The paper presents a high-speed serial interface between external tester and Embedded Deterministic Test (EDT) compression logic hosted by SoC designs. With only a single bidirectional link, the system is capable of feeding distributed heterogeneous cores with hundreds of test channels. Moreover, it synergistically supports EDT bandwidth management to improve the overall test performance. A detailed study indicates a high potential of the serial EDT approach to handle large multicore SoC designs by deploying only a single serial interface and completing the entire test for stuck-at faults in less than one second. Experiments conducted with the help of FPGA–based evaluation platform confirm feasibility and a high effectiveness of the proposed solution.
Historia życia jako terapia - edukacyjny wymiar opowieści w badaniu tożsamości nauczycielek
- Michał Tomasz Tomczak
2014
W artykule prezentowane są założenia metodologiczne oraz fragmenty wyników badań biograficznych nauczycielek. Autor koncentruje się na charakterystyce specyficznego narzędzia badawczego, w założeniu wykraczającego poza wymiar poznawczy, stając się pewnego rodzaju terapią dla jego uczestniczek.
Historical records of organic pollutants in sediment cores
- Paulina Bigus
- Marek Tobiszewski
- Jacek Namieśnik
2014 MARINE POLLUTION BULLETIN
Analyses of sediment core samples are primary sources of historical pollution trends in aquatic systems. Determining organic compounds, such as POPs, in the dated sediments enables the estimation of their temporal concentration changes and the identification of the contaminant origin in local regions. Wars, large-scale fires, economical transitions, and bans on certain chemicals are reflected in the sediment organic compound concentrations. The high POP concentrations in surficial sediments suggest that these chemicals, even after being banned, remain in the environment. Furthermore, vertical profiles can help in understanding the sedimentation process and in estimating effective countermeasures against pollution. Moreover, studies published during the period 1991–2013 on PAHs, PCBs, OCPs, dioxins and dioxin-like compound concentrations in sediment core samples are reviewed.
History and Perspective of Treatment Wetland in Poland – Part One: Lesson learned
- Hanna Obarska-Pempkowiak
- Piotr Kowalik
- Magdalena Gajewska
- Ewa Wojciechowska
2014
Early implementation of treatment wetlands under supervision of the researchers from were quite promising. The constructed facilities ensured effective wastewater treatment and sludge dewatering. In the next years a number of treatment wetland s systems were constructed without following the designing principles and left without proper maintenance. In the consequence this lead to unsatisfactory treatment results. Investigations confirmed that treatment wetlands work effectively only in case when they are adequately designed and properly operated.
History-based dynamic weight voting for multi-agent systems
- Artur Opaliński
2014 Journal of Applied Computer Science
Taking decision in multi-agent systems may involve voting. Two basic voting protocols are surveyed in the paper. Then, a new history-based dynamic weight voting is proposed. This voting protocol allows for identification of the agents which contribute to the correct system decision. The proposed solution is contrasted with majority voting and with weighted average voting, to show its advantages
Holistyczne ujęcie strategii zarządzania wiekiem-myślenie strategiczne a potencjał osób starszych na rynku pracy
- Katarzyna Tubielewicz
2014 Prace Naukowe Wyższej Szkoły Bankowej w Gdańsku
Cel opracowania stanowi zaprezentowanie koncepcji zarządzania wiekiem w całościowym ujęciu wraz ze wskazaniem podstawowych obszarów możliwych do wykorzystania w ramach przyjętego modelu biznesowego opartego na dobrych praktykach zarządzania wiekiem.
Horyzont energoelektroniczny obiektów morskich
- Ryszard Strzelecki
- Piotr Mysiak
- Daniel Wojciechowski
2014 Elektronika : konstrukcje, technologie, zastosowania
W artykule zaprezentowano współczesne kierunki rozwoju energoelektroniki, w tym w szczególności dotyczące obiektów morskich. Przedstawiono podstawowe parametry aktualnie stosowanych w energoelektronice przyrządów półprzewodnikowych, jak również wykazano interdyscyplinarny charakter rozwoju tej dziedziny. Na przykładzie wybranych urządzeń energoelektronicznych przedstawiono ich komercyjne zastosowania oraz podział i miejsce w łańcuchu od wytwórcy energii elektrycznej do odbiorcy. W dalszej części artykułu przedstawiono wybrane zastosowania urządzeń energoelektronicznych na obiektach morskich (statkach, platformach wiertniczych). W końcowej części szczegółowo omówiono przekształtniki energoelektroniczne dużej mocy, w które wyposażane są elektryczne napędy główne na statkach – przedstawiono ich zalety i wady.
How do institutions from Pomerania Province support professional activity of people aged 50 and over?
- Anita Richert-Kaźmierska
2014
The article presents the solutions that were implemented in last years in the pomorskie province with regard to the economic activation of individuals aged 50+. The author presents the priorities in this area included in regional policy and specific initiatives of different types of institutions operating in the region.
How Does International Competitiveness Affect Economic Development? A Two-Phase Hypothesis
- Hanna G. Adamkiewicz
- Stanisław Kot
2014 Pełny tekst Optimum. Studia Ekonomiczne
This paper analyses the impact of international competitiveness on economic development, based on the World Economic Forum Global Competitiveness Index (GCI) and GDP/capita of 125 countries during the period 2007-2010. The results reveal two phases of the evolution of competitiveness. When GCI < 4.5 (on 1-7 scale), any improvement of a country’s competitiveness affects current development more than future development. When a country’s GCI rises above 4.5, further improvements of competitiveness will affect future development more than current development. The 4.5 competitiveness threshold is remarkably stable throughout analyzed period.
HOW EFFICIENT IS NOISE LABELING OF TIRES?
- Beata Świeczko-Żurek
- Jerzy Ejsmont
- Grzegorz Ronowski
2014
Since 2012 all new tires in Europe must be labeled. The label contains general information about tire performance concerning rolling resistance (that corresponds to fuel economy), noise emission and wet grip (only for passenger car tires). Measurements of noise performance of tires must be performed according to the Annex 3 of the Regulation No 117 of the Economic Commission for Europe of the United Nations. The regulation specifies pass-by method of tire/road noise measurements with vehicle tires rolling on the reference surface built according to the standard ISO 10844. The paper presents results of tire/road noise measurements performed at the Technical University of Gdansk for tires with different noise labels and discusses correlation between data stated in the labels and measured noise levels. The measurements were performed by CPX and drum method on different road surfaces or on replica road surfaces. ISO specified surface is not very typical for European road network so ranking of tires obtained on this surface may or may not be representative for real life applications.
How Specific Can We Be with k-NN Classifier?
- Karol Draszawka
- Julian Szymański
2014
This paper discusses the possibility of designing a two stage classifier for large-scale hierarchical and multilabel text classification task, that will be a compromise between two common approaches to this task. First of it is called big-bang, where there is only one classifier that aims to do all the job at once. Top-down approach is the second popular option, in which at each node of categories’ hierarchy, there is a flat classifier that makes a local classification between categories that are immediate descendants of that node. The article focuses on evaluating the performance of a k-NN algorithm at different levels of categories’ hierarchy, aiming to test, whether it will be profitable to make a semi-big-bang step (restricted to a specified level of the hierarchy), followed by a middle-down more detailed classification. Presented empirical experiments are done on Simple English Wikipedia dataset.