2013 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2013

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Influence of a Radio Frequency on RF Fingerprinting Accuracy Based on Ray Tracing Simulation
- Przemysław Woźnica
- Łukasz Kulas
2013
In this paper the influence of a radio signal frequency on performance of Indoor Positioning System based on fingerprinting has been examined using ray-tracing simulations. It has been simulated how spatial distribution of an RF signal strength change with the signal’s frequency. The results were used to show its’ impact on the behavior of localization algorithms that are employing RSS measurements to determine node’s position in wireless sensor networks. Moreover, to give the fair comparison, instead of the overall accuracy calculation it has been proposed to determine IPS accuracy for every logical section of the scene. The proposed approach gave the expected conclusions on how the accuracy of indoor positioning systems based on RF fingerprinting algorithm depends from RF signal’s frequency in simulated area.
Influence of advertisement in social media in knowledge based economy
- Radosław Ślosarski
- Bruno Schivinski
2013
In the era of knowledge based economies every year the number of companies that starting their advertising campaigns increase. According to Social Enterprise Report, 38% of leading companies in Poland have its profile on social networking sites. In this paper, we are going to introduce two case studies. The first one is the advertising campaign of Heyah based on the history of communism. The second case study is the continuation of the well-known advertising campaign of Orange and its lack of effect in social media. Companies should be extremely careful while running their profiles and advertising campaigns in social networking sites, mainly because social services like Facebook allows to the users posting their comments and opinions generating negative word of mouth.
Influence of bush wear in water lubricated marine stern tube bearings with shaft misalignment
- Wojciech Litwin
2013
Water lubricated propeller shaft bearings are frequently employed on modern ships due to their advantages such as durability, simplicity and low price. Specific working conditions on ships cause shaft misalignment which often results in rapid wearing of bush and shaft. Shaft misalignment could be an effect of manufacturing or assembly faults but sometimes it appears due to hull or shaft deformation. The wearing process has influence on bearing hydrodynamic properties because of significant changes in bush geometry. In calculating pressure distribution and load capacity an EHL model was used. In addition, the bush wearing module described in previous works was applied. Calculations were conducted for bearings with length to diameter ratio of 2 (shaft diameter 100 mm and length 200 mm). This is a typical ratio for modern materials accepted by classifications societies for stern tube bearings. The assumption that minimum film thickness equals 5 µm was employed in calculating the maximum bearing hydrodynamic capacity. At every step of the proposed EHL+W model calculation are conducted for progressively increasing values of eccentricity. When the lubrication film thickness falls below the assumed 5 µm a layer of bush surface is removed simulating the wearing process. Frequently when significant shaft misalignment appears, the bearing is working in mixed lubrication regime. In such a situation, the wearing process which starts can progress especially rapidly for stiff composite materials with modules of elasticity equal to approximately 4000 MPa. This effect appears due to significant stress concentration on bush’s edge. The calculations model assumed that the edge load results in wear and change in bush geometry. Modification of the bearing interspace cause change in hydrodynamic properties of the bearing. The results of calculated bearing hydrodynamic capacity as a function of wear are presented in the paper.
Influence of external walls' thermal capacitance on indoor thermal comfort
- Krzysztof Arendt
2013
The doctoral thesis presents the results of numerical investigations on the influence of walls’ thermal capacitance on indoor thermal comfort. A proper set of thermal parameters of a building structure can considerably limit the heating / cooling demand, and passively increase the indoor thermal comfort. However the effect of building thermal capacitance on indoor conditions is complex and not always beneficial. Among a great number of interfering factors are e.g. climatic conditions, building shape, ventilation system type, operational schedule and many others. The aim of the present study is to investigate the potential of high thermal capacitance walls under the climatic conditions typical for Poland. The investigations are based on a number of simulations performed using a numerical model of a part of buildings. The model consists of two main separate components: the indoor air submodel and the external wall submodel. The submodels work together in a co-simulation, exchanging the solution at the common boundaries. A considerable part of the model has been developed by the author. The model treats indoor space as a nonuniform environment, and provides the basic indoor environment parameters affecting the human thermal comfort, i.e. the air temperature and velocity. The output parameters are analyzed separately but they are also used to calculate the expected thermal sensation in the considered space. The evaluation of the walls’ thermal capacitance potential to increase the level of the indoor thermal comfort is based on the results produced by a significant number of various simulations. The analysis covers different wall structures, two different ventilation air exchange rates and two types of the outdoor temperature profiles: (1) one-week sol-air temperature profile and (2) simple step change temperature profile. The results indicate that indoor thermal comfort can be increased by a proper thermal capacitance of building walls. However, it is also shown that the ventilation air exchange rate can have a prevailing influence on indoor conditions, limiting stabilizing effects of the walls’ thermal capacitance.
Influence of Flat Lapping Kinematics on Machinability of Ceramics
- Adam Barylski
- Mariusz Deja
2013 Solid State Phenomena
New tools for flat grinding of ceramics are presented in the paper. Electroplated CBN tools (B64 and B107) were used in a modified single-disc lapping machine configuration. The results from experiments, such as the material removal rate and surface roughness parameters are presented and analyzed. Numerical simulations, based on the model for the shape error and tool wear estimation in machining with flat lapping kinematics, are also presented. The tool life of electroplated tools can be extended by choosing appropriate parameter K related to the process kinematics.
Influence of high temperature air-steam mixture application on time wood drying process
- Jacek Barański
- Maciej Wierzbowski
2013
The results of influence gas-steam mixture drying process on time wood drying process are presented. Wood species, namely oak (Quercus L.), beech (Fagus L.), pine (Pinus L.) and spruce (Picea K.) from the northern part of Pomerania region in Poland, were subject of air-steam mixture drying process. Main focus of those tests was to shorten the time of drying process and afterward to check properties of wood.
Influence of image transformations and quality degradations on SURF detector efficiency
- Piotr Szczuko
2013
A method for task-oriented examination of SURF keypoint detector accuracy is presented in the paper. It consists of generating test images, based on a given exemplar, processed by affine transformations: random rotation and scaling, and varying degree of degradations: darkening, blurring, noising, and compression. Details of applied degradation procedure are presented, followed by essentials of SURF-based images matching. A distance metric is adapted for SURF accuracy assessment. It consists of calculation of Euclidean distances between anchor points in the exemplar and degraded images. Finally, results of tests are presented, and impact of degradation level on SURF accuracy is discussed.
Influence of Ionic Liquid Structure on Supported Ionic Liquid Membranes Effectiveness in Carbon Dioxide/Methane Separation
- Iwona Cichowska-Kopczyńska
- Monika Joskowska
- Bartosz Dębski
- Justyna Łuczak
- Robert Aranowski
2013 Pełny tekst Journal of Chemistry
This paper indicates the possibility of application of imidazolium ionic liquids immobilized in polymeric supports—supported ionic liquid membranes—in CO2 separation from gaseous streams (e.g., biogas). Imidazolium salts containing alkyl fluoride anions, bis(trifluoromethylsulfonyl)imide and trifluoromethanesulfonate, selectively separating CO2 were used. The permeability of CO2 through membranes was investigated under gas pressure of 30 kPa and temperature range 283–298 K. Permeability values occurred to be higher for ionic liquids containing bis(trifluoromethylsulfonyl)imide anion. Moreover, CO2 permeability exhibited an increase with increasing temperature for all investigated systems. Stability of supported ionic liquid membranes was studied. In total, polypropylene membrane revealed the best properties, mechanical stability and observed wettability of this support were better than for polyamide and polyvinylidene fluoride ones. Polyethersulfone supports showed similar contact angles; however, its mechanical stability was significantly lower. Obtained results allowed to evaluate the effectiveness of separation process using selected ILs and supports.
Influence of lightweight structures used in swimming pools and water parks objects on their functionality, building form and spatial-visual effects indoors.
- Marek Sztafrowski
2013
Speaking about architecture of swimming facilities and water parks we have in mind their form, function , design and detail, texture and color. A particularly important element of the architecture of these buildings was and still is the structure.
Influence of nitrogen and organic matter fractions on wastewater treatment in treatment wetland
- Magdalena Gajewska
2013
Municipal wastewater contains both biodegradable and non-degradable pollutants. Moreover, they are present in dissolved, colloidal and particulate forms. These fractions are characterised by various decomposition rates, hence their bioavailability during microbial respiration. It was confirm that biological degradation rate in terms of COD reduction is influenced by particle size speciation. Therefore, the objective of the study was to investigate organic matter (COD) and N fractions during wastewater treatment in treatment wetland with the special respect to vegetative and non-vegetative period. The analyses of samples filtered in the standard way through a 0.45mm pore size filter does not provide reliable information about the dissolved (soluble) and particulate fractions due to the colloids content. Based on content of dissolved, colloidal and particulate forms of organic matter and nitrogen it is possible to estimate their potential for degradations and removal in multistage treatment wetland.
Influence of Osmolytes on Protein and Water Structure: A Step To Understanding the Mechanism of Protein Stabilization
- Piotr Bruździak
- Aneta Panuszko
- Janusz Stangret
2013 JOURNAL OF PHYSICAL CHEMISTRY B
Results concerning the thermostability of hen egg white lysozyme in aqueous solutions with stabilizing osmolytes, trimethylamine-N-oxide (TMAO), glycine (Gly), and its N-methyl derivatives, N-methylglycine (NMG), N,N-dimethylglycine (DMG), and N,N,N-trimethylglycine (betaine, TMG), have been presented. The combination of spectroscopic (IR) and calorimetric (DSC) data allowed us to establish a link between osmolytes’ influence on water structure and their ability to thermally stabilize protein molecule. Structural and energetic characteristics of stabilizing osmolytes’ and lysozyme’s hydration water appear to be very similar. The osmolytes increase lysozyme stabilization in the order bulk water < TMAO < TMG < Gly < DMG < NMG, which is consistent with the order corresponding to the value of the most probable oxygen–oxygen distance of water molecules affected by osmolytes in their surrounding. Obtained results verified the hypothesis concerning the role of water molecules in protein stabilization, explained the osmophobic effect, and finally helped to bring us nearer to the exact mechanism of protein stabilization by osmolytes.
INFLUENCE OF SURFACE CURVATURE ON SESSILE DROPLET CONTACT ANGLE OF NANOFLUIDS
- Janusz Cieśliński
- Katarzyna Ronewicz
2013 Transactions of the Institute of Fluid-Flow Machinery
This paper deals with change in contact angle of droplets of three nanofluids, i.e. water-Al2O3, water-TiO2 and water-Cu. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. Although dispersants were not used to stabilize the suspension, the solutions tested exhibited satisfactory stability. Ultrasonic vibration was used in order to stabilise the dispersion of the nanoparticles. Experimental measurements were performed for horizontal stainless steel (316) tube of three diameters, i.e. 1.6 mm, 3 mm and 5 mm. The results obtained show that the contact angle of tested nanofluids depends strongly on nanoparticle concentration as well as the curvature of the substrate.
Influence of synthesis conditions on zinc oxide nanorode layer morphology
- Konrad Dunst
- Jakub Karczewski
- Piotr Jasiński
2013
In recent years one dimensional (1D) nanostructures (nanotubes, nanowires, nanoribbons and nanorods) have been widely studied. Among studied nano-materials, the greatest interest can be seen for zinc oxide (ZnO). However, there is still a need for simple, inexpensive and reproducible fabrication method. In the literature different fabrication methods can be found, most of them requires expensive equipment and involve complex fabrication process. An alternative is chemical bath deposition (CBD). This method is simpler than the others and does not require sophisticated equipment. In this paper the CBD method is studied for fabrication of ZnO nanorods. The influence of synthesis temperature and time are studied. Relation between these conditions and ZnO morphology are showed. The length and diameter of ZnO nanorods are taken under consideration. Typically, the synthesized ZnO nanorods are 100-300 nm in diameter and 0.8-4 um long.
Influence of the boron doping level on the electrochemical oxidation of the azo dyes at Si/BDD thin film electrodes
- Robert Bogdanowicz
- Aleksandra Fabiańska
- Łukasz Gołuński
- Michał Sobaszek
- Marcin Gnyba
- Jacek Ryl
- Kazimierz Darowicki
- T Ossowski
- Stoffel D. Janssens
- Ken Haenen
- E.m. Siedlecka
2013 DIAMOND AND RELATED MATERIALS
In this study the efficiency of electrochemical oxidation of aromatic pollutants, such as reactive dyes, at boron-doped diamond on silicon (Si/BDD) electrodes was investigated. The level of [B]/[C] ratio which is effective for the degradation and mineralization of selected aromatic pollutants, and the impact of [B]/[C] ratio on the crystalline structure, layer conductivity and relative sp3/sp2 coefficient of a BDD electrode were also studied. The thin film microcrystalline electrodes have been deposited on highly doped silicon substrates via MW PE CVD. Si/BDD electrodes were synthesized for different [B]/[C] ratios of the gas phase. Mechanical and chemical stability of the electrodes was achieved for the microcrystalline layer with relatively high sp3/sp2 band ratio. Layer morphology and crystallite size distribution were analyzed by SEM. The resistivity of BDD electrodes was studied using four-point probe measurements. The relative sp3/sp2 band ratios were determined by deconvolution of Raman and X-ray photoelectron spectra. The efficiency of degradation and mineralization of the reactive azo dye rubin F-2B was estimated based on the absorbance measurements at 545 nm. The influence of commonly used electrolytes NaCl and Na2SO4 on the dye removal efficiency was also investigated. The results suggest that, in general, the oxidation occurs indirectly at the anode through generation of hydroxyl radicals •OH, which react with the dye in a very fast and non-selective manner. In NaCl electrolyte the dye was also decomposed by more selective, active chlorine species (Cl2, HOCl). However the efficiency of this process in BDD depended on the electrode's doping level. Higher amounts of dopant on the surface of BDD resulted in the higher efficiency of dye removal in both electrolytes.
Influence of the internal electrolyte composition on amperometric sulphur dioxide sensor properties
- Anna Strzelczyk
- Grzegorz Jasiński
- Bogdan Chachulski
2013
In this work amperometric sulphur dioxide sensor with a liquid electrolyte, a mercury sulphate reference electrode and solid polymer electrolyte (Nafion) covered with gold as a working electrode will be presented. The main goal of this research is to determine the influence of internal electrolyte composition on the sensor properties. Sensor filled with 1M and 5M sulphuric acid has been investigated.
INFLUENCE OF TIME ON THE BEARING CAPACITY OF PRECAST PILES
- Kazimierz Gwizdała
- Paweł Więcławski
2013 Pełny tekst Studia Geotechnica et Mechanica
One of the most popular types of foundations in layered subsoil with very differentiated soil shear strengths are precast piles. One of the reasons is a fact that we can well control the driving process during the installation of these piles. The principles of the assessment of bearing capacity and settlements of the piles given by Eurocode 7, concentrate on two main methods, i.e. Static Pile Load Tests (SPLT) and Dynamic Driving Analysis (PDA). However, the evaluation of real load-settlement curve for piles being driven in layered subsoil, where non-cohesive and cohesive soils oc-cur alternately, is not so easy and straightforward task. In the paper the results of both SPLT and PDA tests for the objects on the Polish highways are presented. Field investigations carried out in various time from the pile installations (from 7 to 90 days) revealed an increase of bearing capacity with time. The reason of it may be a change of the soil state near the piles due to its driving (displacement piles) as well as a change of microstructure at the contact of soil and pile shaft. The results of load tests were referred to the geotechnical parameters of the subsoil, which was recognized by traditional borings and CPTU tests. The results of tests allow for the assessment of phenomena occurring with time and prediction of bearing capacity of precast piles.
Influence of Wastewater Treatment Technology on Particle Size Distribution in the Effluent
- Magdalena Gajewska
- Marzena Stosik
- Hanna Obarska-Pempkowiak
- Ewa Wojciechowska
2013 Pełny tekst Rocznik Ochrona Środowiska
Suspended solids in water and wastewater usually carry quite a large load of pollutants (organic substances, nutrients, heavy metals, etc.) adsorbed on the particles surface. Particles of different sizes carry different types and quantities of pollutants. Therefore, particle size distribution is of importance in waster and wastewater treatment. In the article the influence of different treatment technologies on particle size distribution in the effluent was assessed. The analyses covered the effluents from two municipal wastewater treatment plants, drainage water, clean stormwater, oil-contaminated water and industrial sewage treated at the oil refinery and the water of a stream contaminated with stormwater run-off, treated in a constructed wetland. The equivalent diameters of particles were similar for all analyzed types of wastewater, however the share of different particle sizes in the total volume was different.
Informal projects management with volunteers participation
- Marek Wirkus
2013 Journal for the Advancement of Performance Information and Valu
The article briefly presents some experiences and results of research which has been conducted in order to identify key elements influencing the success of projects managed in informal way with volunteers’ participation. These experiences were collected during the realization of several “soft” projects. The general aims of these projects were sports competitions’ organisation, cultural events and charity projects for big groups of people. Within research of project management, the following issues were discussed: the project area of activity and function possible to make by volunteers, the rules of volunteers employment in project, factors describing key elements influencing the success of projects including: the trust as the base of informal projects management, wide-understand communication, cooperation and team work. Project risk, reporting and controls of project execution and the role and element of project culture as elements influenced on project success are also discussed.
Information Retrieval with the Use of Music Clustering by Directions Algorithm
- Adam Kaczmarek
2013
This paper introduces the Music Clustering by Directions (MCBD) algorithm. The algorithm is designed to support users of query by humming systems in formulating queries. This kind of systems makes it possible to retrieve songs and tunes on the basis of a melody recorded by the user. The Music Clustering by Directions algorithm is a kind of an interactive query expansion method. On the basis of query, the algorithm provides suggestions that may be used to enhance the query. The MCBD algorithm is bases on the Clustering by Directions (CBD) that was designed to support users of web search engines in information retrieval. The MCBD algorithm is used for retrieval of music documents similarly as the CBD algorithm is used with text documents. This paper also introduces a new kind of interface designed to perform interactive query expansion in query by humming systems. The interface is a kind of tag cloud applied to music information retrieval systems.
Inhibition of T-type calcium channel disrupts Akt signaling and promotes apoptosis in glioblastoma cells.
- Nicholas C.K. Valerie
- Barbara Dziegielewska
- Amol S. Hosing
- Ewa Augustin
- Lloyd S. Gray
- David L. Brautigan
- James M. Larner
- Jaroslaw Dziegielewski
2013 BIOCHEMICAL PHARMACOLOGY
Glioblastoma multiforme (GBM) are brain tumors that are exceptionally resitant to both radio- and chemotherapy regimens and novel approaches to treatment are needed. T-type calcium channels are one type of low voltage-gated channel (LVCC) involved in embryonic cell proliferation and differentiation; however they are often over-expressed in tumors, including GBM. In this study, we found that inhibition of T-type Ca channels in GBM cells significantly reduced their survival and resistance to therapy. Moreover, either T-type selective antagonists, such as mibefradil, or siRNA-mediated knockdown of the T-type channel alpha subunits not only reduced cell viability and clonogenic potential, but also induced apoptosis. In response to channel blockade or ablation, we observed reduced phosphorylation of Akt and Rictor, suggesting inhibition of the mTORC2/Akt pathway. This was followed by reduction in phosphorylation of anti-apoptotic Bad and caspases activation. The apoptotic response was specific for T-type Ca channels, as inhibition of L-type Ca channels did not induce similar effects. Our results implicate T-type Ca channels as distinct entities for survival signaling in GBM cells and suggest that they are a novel molecular target for tumor therapy.