2013 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2013

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Modeling hydrolysis of slowly biodegradable organic compounds in biological nutrient removal activated sludge systems
- Jakub Drewnowski
- Jacek Mąkinia
2013 WATER SCIENCE AND TECHNOLOGY
Hydrolysis is an important process in biological wastewater treatment and is known to be the ratelimiting step in organic carbon removal from municipal or industrial wastewater. The influence of the readily biodegradable chemical oxygen demand fraction in biological wastewater treatment systems has been extensively investigated, but little is known about the effects of slowly biodegradable substrate (XS) on denitrification and enhanced biological phosphorus removal. The biodegradation of XS is initiated by hydrolysis, which is an integral part of activated sludge models, such as the Activated Sludge Model no. 2d (ASM2d). This process is slower than heterotrophic growth and thus becomes the rate-limiting step for the biodegradation of organic compounds. The aim of this study was to evaluate different concepts of modeling the hydrolysis process using the original and modified version of ASM2d. Batch test results obtained at a large biological nutrient removal (BNR) plant in Gdansk (Poland) provided an experimental database for comparison of the two model predictions. Both models were compared in terms of their predictions for the most important process rates in BNR activated sludge systems. In comparison with the orginal ASM2d, the modified model had no or only minor effect on the predicted nitrate utilization rate, phosphate release rate and anoxic/aerobic phosphate uptake rate, but better predicted the oxygen uptake rate. The average ARDs (average relative deviations) were 19.0 and 29.3% (original ASM2d) vs. 13.4 and 20.4% (modified ASM2d), respectively, for the settled wastewater without pretreatment and after coagulation–flocculation.
Modeling of Performance, Reliability and Energy Efficiency in Large-Scale Computational Environments
- Jarosław Kuchta
2013
Large scale of complexity of distributed computational systems imposes special challenges for prediction of quality in such systems. Existing quality models for lower-scale systems include functionality, performance, reliability, flexibility and usability. Among these attributes, performance and reliability have a particular significance to the large-scale systems computing quality modeling due to their strong dependence on the system configuration. The system configuration may has also influence to overall system energy consumption. This article presents a quality model of the large-scale systems computations and the analysis of performance, reliability and energy consumption dependency on system configuration.
Modeling the Influence of Salts on the Critical Micelle Concentration of Ionic Surfactants
- Ulrich Preiss
- Philipp Eiden
- Justyna Łuczak
- Christian Jungnickel
2013 JOURNAL OF COLLOID AND INTERFACE SCIENCE
We show for the first time that a phenomenological, augmented volume-based thermodynamics (aVBT) model is capable to predict the critical micelle concentrations of ionic surfactants, including ionic liquids, with added salts. The model also adjusts for the type of salt added by including its molecular volume, which might form a connection to the Hofmeister effect. The other physico-chemically relevant quantities included in the model include surface area and solvation enthalpies.
Modélisation des machines synchrones par des systèmes d’ordre un demi. Procédure d’identification des paramètres du schéma équivalent, analyse de sensibilité des paramètres.
- Szymon Racewicz
2013
Ce livre présente de nouveaux modèles de machines synchrones (alternateurs à pôles saillants et alternateur à aimants permanents). Les schémas équivalents de ces modèles sont établis en utilisant la modélisation fractionnaire. Ceci permet de construire des modèles les plus compacts possibles, c’est-à-dire d’ordre réduit. Les branches (R-L) dans le schéma équivalent classique, décrivant les différentes parties de la machine où les courants induits se développent, sont remplacées par des impédances d’ordre ½ de type « inductif » et « résistive », calculées directement à partir de l’équation de diffusion du champ magnétique, respectivement dans une tôle ferromagnétique et une barre conductrice. L’identification des paramètres du schéma équivalent est réalisée par rapport aux données SSFR de deux turboalternateurs (de puissance très différente), en utilisant la méthode des moindres carrés. Les calculs pour l’identification des paramètres ainsi que la validation expérimentale du modèle d’un alternateur à pôles saillant ont été fait à l’aide d’un programme Matlab.
Modelling of behavior of plain concrete using DEM
- Michał Nitka
- Andrzej Tejchman-Konarzewski
2013
W artykule pokazano rozwój różnych zjawisk mikrostrukturalnych na poziomie kruszywa w betonie podczas jednoosiowego ściskania i rozciągania.. Obliczenia wykonano stosując metodę DEM. Wyniki na poziomie globalnym porównano doświadczalnymi. Szczególna uwagę zwrócono na propagację rys i szerokość lokalizacji odkształceń.
Modelling Of Commercial Websites. A New Perspective On Usability And Customer Relation
- Igor Garnik
- Beata Basińska
2013 Pełny tekst Studia Ekonomiczne. Zeszyty Naukowe Uniwersytetu Ekonomicznego w Katowicach
From an economic point of view, a critical aspect of online services is their ability to retain customers. The aim of presented study was the use of a layered model VIPR (Visual - Interaction - Process - Relation ) for commercial services online. The indicator of trust and establishing lasting relationships were assessment achieved from experienced users of commercial online services (n = 207), obtained by means of Web Credibility Scale Commercial Services, which measures eight factors: visual clarity, ease of use, interactivity, user guidance, recommendations, customer care, information content and personalization. According to VIPR Model, visual clarity, ease of use, interactivity and information content created one single group of factors (layer). Each additional factor was a separate item. For customers of least important to inspire confidence were visual clarity and ease of use (basic values, the area of an individual). Top evaluated were personalization and recommendations (value added social area). Especially, recommendations represent a new user needs that have emerged with the development of competition in the market of online services. Model VIPR has been positively verified. Indication of two dimensions: core/added values and personal/social area gives a new perspective on human-computer interaction.
Modelling of cutting by means of fracture mechanics
- Lubomir Javorek
- Kazimierz Orłowski
- Jaroslav Lalik
- Daniel Chuchała
2013
The suitability of modern fracture mechanic theory was proved for the estimation of the cutting force and the cutting specific resistance. This paper shows modification of Ernst-Merchant theory and its application for determination some other properties of wood sample. This theory is acceptable for evaluation of shear yield stresses and shear plane angle. Sawing by gang saw machine was used as a process similar to the orthogonal cutting. English oak was used as a machined wood species.
MODELLING OF CUTTING BY MEANS OF FRACTURE MECHANICS
- Lubomir Javorek
- Kazimierz Orłowski
- Jaroslav Lalik
- Daniel Chuchała
2013 Pełny tekst Pro ligno
The suitability of modern fracture mechanic theory was proved for the estimation of the cutting force and the cutting specific resistance. This paper shows modification of Ernst-Merchant theory and its application for determination some other properties of wood sample. This theory is acceptable for evaluation of shear yield stresses and shear plane angle. Sawing by gang saw machine was used as a process similar to the orthogonal cutting. English oak was used as a machined wood species.
Modelling of Geared Multi-Rotor System
- Cezary Orlikowski
- Rafał Hein
2013 Solid State Phenomena
In the paper the method of modelling a speed-varying geared rotor system is presented. The proposed approach enables us to obtain an accurate low-order lumped parameter representation of the investigated system. The final model consists of reduced modal models of an undamped beam/torsional shaft system as well as a spatially lumped model of other linear and nonlinear phenomena including gear mesh interaction.
Modelling of planar movement dynamics of upper limb
- Wiktoria Wojnicz
- Edmund Wittbrodt
2013
The original model describing planar movement dynamics of upper limb is presented. The upper limb is modelled as two-joints system loaded by external forces and internal forces of striated skeletal muscles. A behaviour of each muscle is modelled as a system composed of serially linked rheologic fragments that have different mechanical properties. These muscle models allow us to simulate a behaviour of short fusiform muscle (3DOF model), average fusiform muscle (5DOF model) and long fusiform muscle (7DOF model). The upper limb is modelled as a double pendulum (2DOF model) and a double pendulum in a planar movement (4DOF model). Taking into account in a model of upper limb dynamics an influence of: a) single short fusiform muscle model, one can obtain a model of upper limb dynamics increased by two degrees of freedom; b) single average fusiform muscle model, one can obtain a model of upper limb dynamics increased by four degrees of freedom; c) single long fusiform muscle model, one can obtain a model of upper limb dynamics increased by six degrees of freedom. The problem of control of upper limb dynamics model is also considered in a paper.
Modelling of power electronic compensators for the analysis of power system operation
- Robert Kowalak
2013 Pełny tekst Acta Energetica
The article presents selected methods of modelling power electronic compensators in order to analyze their operation in the power systems. Advantages and disadvantages of models have been shown with an indication of their usefulness for modelling specific phenomena.
Modelling of reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
- Ireneusz Marzec
- Łukasz Skarżyński
- Jerzy Bobiński
- Andrzej Tejchman-Konarzewski
2013 Computers and Concrete
W artykule omówiono wyniki modelowania numerycznego MES zachowania się wysokich belek żelbetowych podczas zniszczenia mieszanego ścinanie-rozciąganie. Obliczenia wykonano stosując różne modele dla betonu rozszerzone o długość charakterystyczną mikrostruktury w oparciu o teorie nielokalna. Otrzymano dobrą zgodność z wynikami doświadczalnymi.
Modelling of Ship’s Heeling and Rolling for the Purpose of Gantry Control Improvement in the Course of Cargo Handling Operations in Sea Ports
- Przemysław Krata
- Janusz Szpytko
- Adam Weintrit
2013 Solid State Phenomena
The paper presents two proposals of models of interaction between a ship and cargo being loaded or discharged by a gantry in port, in terms of heeling and rolling of the vessel. The main purpose of such modelling is the need for improvement of gantry control with regard to faster operations thanks to more accurate estimation of level and moment of cargo release from a gantry hook or spreader. The study may be the contribution to the development of gantry control systems in sea ports.
Modelling of the Baumann turbine stage operation Part II. Free and kinetic vibrations
- Krzysztof Jesionek
- Jarosław Kron
- Witold Zakrzewski
- Daniel Sławiński
- Sebastian Kornet
- Paweł Ziółkowski
- Janusz Badur
2013 ARCHIWUM ENERGETYKI / ARCHIVES OF ENERGETICS
In this paper has been presented a methodology of validation a novel mathematical model dedicated to evaluation and prediction of material degradation and demage of steam turbine elements such as blades, valves and pipes due to three mechanisms: stress-corosion, high-temperature creep and low-cyclic fatigue. The validation concept is based on an experimental setup manufactured in the Laboratory of Faculty of Mechanical and Power Engineering, Wrocław UT. The concept of validation by comparison of measured and numerically predicted eigen-frequencies and eigen-modes of different turbine elements within labolatory conditions are presented, and mathematical models of three damage mechanisms have been described. Using the mentioned method of experimental validation based on comparisons of eigen-frequencies, we could calibrate yet unkwown coefficients in the turbine damage model. A practical aim is an implementation of a novel life-time module for the BOTT (block of thermal stresses restriction) system. In practicular the stress-corrosion factor will be dded numerical control system. In particular the stress-corrosion factor will be added for the advanced numerical control system, creating in such way a universal, flexible and a complete tool for monitoring degrees od degradation, corrosion and damage of critical points in a steam turbine.
MODELLING OF TRANSIENT FLOW IN STORM SEWERS
- Michał Szydłowski
2013
The paper focuses on the assessment of second-order explicit numerical scheme for unsteady flows in sewers. In order to simulate the pressurized flow the 'Preissmann slot' concept is implemented. For simulation of the transcritical flow the original and improved McCormack scheme is used. The calculated results are compared with numerical solutions and laboratory measurements published in the technical literature. Moreover, the aim of this paper is to present the comparison between calculated and measured at the hydraulic laboratory of Gdańsk University of Technology (GUT) pressure values which were observed during experiment for water flow with pipe pressurization. The analysis proves that proposed numerical approach to flow simulation is a sufficiently accurate and reliable technique for prediction of basic storm sewers flow parameters.
Modelling processes for Polish civil aviation market
- Aleksander Orłowski
- Edward Szczerbicki
2013
The present , paper is the first step in research of Polish civil aviation market, focusing on the area of civil, legacy airlines. First, the market is described with its players, current conditions and its main problems. Next, the tools which are currently used for the prognosis processes are presented. Finally, the idea of a new model (fuzzy model) for the process of prognosis is presented.
Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
- Ireneusz Marzec
- Łukasz Skarżyński
- Jerzy Bobiński
- Andrzej Tejchman-Konarzewski
2013 Computers and Concrete
The paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack and isotropic damage model were applied. Finally, an elasto-plastic-damage model was used. To ensure mesh-independent FE results, to describe strain localization in concrete and to capture a deterministic size effect, all models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. Bond-slip between concrete and reinforcement was considered. The numerical results were directly compared with the corresponding laboratory tests performed by Walraven and Lehwalter (1994). The advantages and disadvantages of enhanced models to model the reinforced concrete behaviour were outlined.
Modelling the effect of composition on the tensile properties of concrete
- Łukasz Skarżyński
- Andrzej Tejchman-Konarzewski
2013
Rozdział omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu. Zaproponowano 2 metody określenia reprezentatywnego elementu objętościowego w betonie.
Modelling water flow in unsaturated porous media: Accounting for nonlinear permeability and material heterogeneity
- Adam Szymkiewicz
2013
W pracy przedstawiono problematykę matematycznego modelowania przepływów w nienasyconych ośrodkach porowatych, ze szczególnym uwzględnieniem dwóch aspektów. Pierwszym z nich jest obliczanie średniego współczynnika przewodności hydraulicznej między węzłami siatki w numerycznym rozwiązaniu równania przepływu nienasyconego. Drugim zagadnieniem jest wpływ lokalnej zmienności parametrów ośrodka porowatego (współczynnika przewodności i ciśnienia wejścia powietrza) na przepływ w skali makroskopowej.
Modelowanie dynamiki warstwy gruntu na stole sejsmicznym
- Andrzej Sawicki
- Robert Jankowski
- Marek Kulczykowski
- Waldemar Świdziński
2013 Pełny tekst Inżynieria Morska i Geotechnika
Podsumowano wyniki badań warstwy gruntu sypkiego na stole sejsmicznym. Pierwsza grupa badań dotyczyła analizy osiadań warstwy gruntu suchego, poddanego poziomym drganiom o zadanej częstości i amplitudzie przyspieszenia, głównie harmonicznego. Druga grupa badań dotyczyła dynamiki warstwy nawodnionego gruntu, przy ustalonej amplitudzie poziomego przyspieszenia oraz różnych częstościach. Opisano same doświadczenia, podsumowano najważniejsze wyniki oraz przedstawiono wnioski. Zaprezentowano algorytm analizy teoretycznej problemu upłynnienia warstwy. Zestawiono podstawowe parametry badanego gruntu oraz podano źródłową literaturę.