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Search results for: operating point stability
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A literature survey of the influence of preform reheating and stretch blow molding with hot mold process parameters on the properties of PET containers. Part I.
PublicationThe hot fill process is an inexpensive conventional filling technology for high-acidity products (pH < 4.5). It allows certain drinks (sensitive beverages such as fruit and vegetable juices, nectars, soft drinks, vitaminized water) to be stored at ambient temperature without the need for chemical preservatives. The primary feature of the bottles used in the hot fill process is their temperature stability, i.e. the ability to retain...
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Mathematical analysis of a generalised p53-Mdm2 protein gene expression model
PublicationWe propose the generalisation of the p53-Mdm2 protein gene expression model introduced by Monk (2003). We investigate the stability of a unique positive steady state and formulate conditions which guarantee the occurrence of the Hopf bifurcation. We show that oscillatory behaviour can be caused not only by time lag in protein transcription process, but also can be present in the model without time delay. Moreover, we investigate...
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Rapid multi-objective design of integrated on-chip inductors by means of Pareto front exploration and design extrapolation
PublicationIdentification of the best trade-offs between conflicting design objectives allows for making educated design decisions as well as assessing suitability of a given component or circuit for a specific application. In case of inductors, the typical objectives include maximization of the quality factor and minimization of the layout area, as well as maintaining a required inductance at a given operating frequency. This work demonstrates...
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Piotr Chrzan prof. dr hab. inż.
PeopleUrodził się w 1954 r. w Sopocie. Jest absolwentem Wydziału Elektroniki Politechniki Gdańskiej (1978). W 1980 r. podjął pracę na Wydziale Elektrycznym w zespole prof. Jerzego Jaczewskiego. W 1988 r. uzyskał stopień naukowy doktora nauk technicznych, habilitację w 1999 r., w zakresie elektrotechniki: energoelektroniki i automatyki napędu, a tytuł profesora w 2017 r. Był promotorem 6 obronionych prac doktorskich (w tym 3 z wyróżnieniem)....
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BJS-03 DO WE NEED FIXATION OF THE MESH IN LAPAROENDOSCOPIC TECHNIQUES FOR M3 INGUINAL DEFECTS? AN EXPERIMENTAL STUDY
PublicationThe authors conducted a research experiment to verify the hypothesis that it is possible to preserve the mesh in the operating field in large direct hernias (M3) without the need to use fixing materials. The results showed that mesh fixation is not the only alternative to preventing recurrence in complex defects and that the type of implant seems to be a key factor from the point of view of mechanics and biophysics.
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Z type Observer Backstepping For Induction Machines
PublicationThis paper contains a relatively new synthesis method for non-linear objects, named backstepping. This method can be used to obtain the observer structure. The paper presents the structure of the speed observer which is a new proposition of observer backstepping with additional state variables marked Z. The rotor speed can be estimated in three different ways. The first is based on the adaptive approach, the second on the nonadaptive...
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Algebraic periods and minimal number of periodic points for smooth self-maps of 1-connected 4-manifolds with definite intersection forms
PublicationLet M be a closed 1-connected smooth 4-manifolds, and let r be a non-negative integer. We study the problem of finding minimal number of r-periodic points in the smooth homotopy class of a given map f: M-->M. This task is related to determining a topological invariant D^4_r[f], defined in Graff and Jezierski (Forum Math 21(3):491–509, 2009), expressed in terms of Lefschetz numbers of iterations and local fixed point indices of...
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Paweł Szymon Dąbrowski dr inż.
PeopleDr. Eng. Paweł Szymon Dąbrowski studied geodesy and cartography at the University of Warmia and Mazury in Olsztyn from 2004-2009, where he obtained the title of Master of Science in Engineering. In the years 2009-2016, he worked as a land surveyor in Iława and Gdańsk. He gained professional experience during the construction of the Pomeranian Metropolitan Railway, which helped him obtain a national surveying license in 2015. In...
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The influence of synthesis method on the microstructure and catalytic performance of Y 0.07 Sr 0.93 Ti 0.8 Fe 0.2 O 3-δ in synthetic biogas operated solid oxide fuel cells
PublicationThe Y0.07Sr0.93Ti0.8Fe0.2O3-δ (YSTF) material was fabricated using three different synthesis methods: modified polymer precursor method (MPP), Pechini method and a solid state reaction method. It was applied as an anode catalytic material for biogas reforming in solid oxide fuel cells. Clear differences in the microstructure of fabricated catalytic layers were found, mainly with respect to a grain size and distribution of grains....
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Energy Loss Coefficients ki in a Displacement Pump and Hydraulic Motor used in Hydrostatic Drives
PublicationThe article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating...
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Wykorzystaniem metody elementów skończonych w obliczaniu stateczności silosu z blachy falistej = Finite element method in determining stability of with corrugated walls strengthened by vertical columns of thin walled open cross section
PublicationGwałtowny rozwój zastosowania MES w działalności inżynierskiej nastąpił w połowie lat osiemdziesiątych w związku z pojawieniem się komputerów osobistych (PC), na które przeniesione zostały programy z dużych jednostek obliczeniowych. W ten sposób efektywne narzędzie rozwiązywania problemów analiz i projektowania jakim jest MES, stało się powszechnie dostępne. W artykule przedstawiono zastosowanie MES w analizie stateczności stalowego...
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Ireneusz Kreja dr hab. inż.
PeopleGraduated from the mathematical class at the Nicolaus Copernicus High School in Gdańsk (1974). Master of Sciences in Civil Engineering after studies at Gdansk University of Technology (GUT), Poland (1974-1979). Since 1979 became an employee of the GUT. In 1989 earned a Ph.D. degree in Civil Engineering (with grade "Summa cum Laude") from the GUT. In 2008 obtained a D. Sc. (Habilitation) degree in Civil Engineering (with grade...
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Wybrane problemy plastyczności w płaskim ośrodku mikropolarnym
PublicationW pracy analizuje się sprężysto-plastyczny płaski ośrodek mikropolarny. Do rozwiązań równań plastyczności wykorzystuje się technikę Closest Point Projection Method. Przedstawiono przykład numeryczny w płaskim stanie naprężenia, zasygnalizowano problem lokalizacji w zadaniach z osłabieniem materiału.
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Thermal buckling of functionally graded piezomagnetic micro- and nanobeams presenting the flexomagnetic effect
PublicationGalerkin weighted residual method (GWRM) is applied and implemented to address the axial stability and bifurcation point of a functionally graded piezomagnetic structure containing flexomagneticity in a thermal environment. The continuum specimen involves an exponential mass distributed in a heterogeneous media with a constant square cross section. The physical neutral plane is investigated to postulate functionally graded material...
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Running performance of an aerodynamic journal bearing with squeeze film effect
PublicationResults of theoretical and experimental studies concerning the performance of an aerodynamic journal bearing of which running is assisted by squeeze film ultrasonic levitation (SFUL) are presented in this paper. The SFUL mechanism not only can separate journal from the bearing at the start and stop phases of operation but also can significantly contribute to the dynamic stability of the bearing when it runs at speed. Computer calculations...
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Requirements for Residual Current Devices Intended for Electric Vehicle Charging Systems
PublicationThe properties of residual current devices have been presented from the point of view of their ability to detect a specific shape of the residual current waveform. Moreover, the standard requirements relating to residual current protection used in electric vehicle charging installations have been pointed out. The operating characteristics of the IC-CPD and RDC-DD protections, which are intended for charging electric vehicles in...
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Inverse shadowing and related measures
PublicationWe study various weaker forms of the inverse shadowing property for discrete dynamical systems on a smooth compact manifold. First, we introduce the so-called ergodic inverse shadowing property (Birkhoff averages of continuous functions along an exact trajectory and the approximating one are close). We demonstrate that this property implies the continuity of the set of invariant measures in the Hausdorff metric. We show that the...
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Patryk Ziółkowski dr inż.
PeopleAssistant Professor at Gdansk Tech. He participated in international projects, including projects for the Ministry of Transportation of the State of Alabama (2015), he is also the winner of a grant from the Kosciuszko Foundation for conducting research in the USA, which he completed in 2018. An expert in the field of artificial intelligence. His main area of research interest is the application of artificial intelligence in Civil...
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Evaluation of the electrochemical performance of CPMD in ZICs with 3M ZnSO4 electrolyte
Open Research DataThese data contain the results of the electrochemical performance measurements of CPMD in ZICs with 3M ZnSO4 electrolyte, incl. CGD (galvanostatic charge-discharge ) curve and cycling stability of CPMD. Sample abbreviations (CPMD) are in agreement with the markings used in the linked publication.
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Kazimierz Kosmowski prof. dr hab. inż.
PeopleKazimierz Tadeusz Kosmowski (ur. 12 maja 1947 r. w Nakle nad Notecią) – specjalizacja z zakresu niezawodności i bezpieczeństwa systemów technicznych. Prowadzi badania dotyczące metod identyfikacji zagrożeń oraz analizy i oceny ryzyka ukierunkowanych na obiekty przemysłowe i systemy infrastruktury krytycznej w cyklu życia. Aktualne zainteresowania naukowe dotyczą współdziałania systemów OT i IT oraz bezpieczeństwa funkcjonalnego...
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Acoustic journal bearing – Performance under various load and speed conditions speed conditions
PublicationThe paper presents results of experimental testing aiming at finding out what effect system of piezo-electric actuators (PZTs)attached to an aerodynamic journal bearing has on the magnitude of shaft's motion within the bearing operating at specified speed and load. The results clearly demonstrate effectiveness of PZTs in mitigating the shaft's motion thus contributing to the increased stability of the bearing. This stabilizing...
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Electrochemical studies of symmetrical supercapacitors based on BDD, Mn-BDD, Mn-BDD(AN) electrodes
Open Research DataElectrochemical performance of a Supercapacitor device in PVA-H2SO4 gelled electrolyte: Cyclic voltammograms at varying scan rates ranging from 10 to 1000 mV s−1, galvanostatic charge-discharge curves with varying current density, cyclic stability (88000 charge-discharge cycles).
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Dual-Polarized Wideband Bandpass Metasurface-Based Filter
PublicationThis paper presents a novel metasurface-based bandpass filter. The structure is realized by simply patterning a double-sided AD250 substrate, and does not require any vias or insertion of lumped elements. The top layer is an annular- aperture-array with multiple inner conductors, whereas the bottom layer is a first-order Hilbert-curve array. FEM-based simulation results of the filter are obtained using HFSS. The experimental validation...
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Mechanics of materials (PG_00057378), W/Ć, BM, II stop., sem1,3, lato, 2023/24
e-Learning CoursesThe aim of this course is providing knowledge in the field of analysis and solving problems of mechanics and strength of one-dimensional systems (bars, beams, frames) and selected two-dimensional systems (shields, plates); preparing the student to solve problems involving complex cases of material strength; developing the ability to assess the stability of structural elements (forms of stability loss, critical forces); consolidation...
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Multiregional PI control strategy for dissolved oxygen and aeration system control at biological wastewater treatment plant
PublicationThe dissolved oxygen is a key parameter for biological processes at wastewater treatment plant. The dissolved oxygen tracking problem is one of the most complex and fundamental issue of biological processes. The paper proposes a new multiregional control strategy for dissolved oxygen tracking problem. The aeration system is included in overall control structure. The control mechanism within the operating point area is based on...
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Monitoring of current collectors on the railway line
PublicationProper cooperation the current collectors and the overhead line is a pre-requisite for reliable and safe operation of railway transport. Instances of maladjustment and, in some cases, damage to the current collectors, occur between periodic inspections of the rolling stock. In order to detect such anomalies quickly, the test stand was developed, with the aim of monitoring the technical state of the current collectors under operating...
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Improving sensitivity of residual current transformers to high frequency earth fault currents
PublicationFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed...
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Simplified, multiregional fuzzy model of a nuclear power plant steam turbine
PublicationPower systems, including steam turbines and synchronous generators, are complex nonlinear systems with parameters varying over time. The paper presents the developed simplified, multiregional fuzzy model of the steam turbine of a nuclear power plant turbine generator set and compares the results with a full nonlinear model and commonly used linear input-output model of a steam turbine. The proposed model consist of series of linear...
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Power System Stabilizer as a Part of a Generator MPC Adaptive Predictive Control System
PublicationIn this paper, a model predictive controller based on a generator model for prediction purposes is proposed to replace a standard generator controller with a stabilizer of a power system. Such a local controller utilizes an input-output model of the system taking into consideration not only a generator voltage Ug but also an additional, auxiliary signal (e.g., α, Pg, or ωg). This additional piece of information allows for taking...
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Numerical Issues and Approximated Models for the Diagnosis of Transmission Pipelines
PublicationThe chapter concerns numerical issues encountered when the pipeline flow process is modeled as a discrete-time state-space model. In particular, issues related to computational complexity and computability are discussed, i.e., simulation feasibility which is connected to the notions of singularity and stability of the model. These properties are critical if a diagnostic system is based on a discrete mathematical model of the flow...
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Integrated monitoring, control and security of Critical Infrastructure Systems
PublicationModern societies have reached a point where everyday life relies heavily on desired operation of critical infrastructures, in spite of accidental failures and/or deliberate attacks. The issue of desired performance operation of CIS at high security level receives considerable attention worldwide. The pioneering generic methodologies and methods are presented in the paper project for designing systems capable of achieving these...
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Sectors in Poland - Patterns of Concentration
PublicationThe main aim of the paper presented below, is to analysefrom theoretical point of view market concentration as economicproblem. The authors come out of defining market concentration, theypresent basic concentration measures, and characterize sectors onPoland on that ground. In the empirical part, the authors haveanalysed patterns of concentration of 35 sectors in Poland in timeperiod 1997-2006. We draw on recently made available...
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MRAS-Based Switching Linear Feedback Strategy for Sensorless Speed Control of Induction Motor Drives
PublicationThis paper presents a newly designed switching linear feedback structure of sliding mode control (SLF-SMC) plugged with an model reference adaptive system (MRAS) based sensorless fieldoriented control (SFOC) for induction motor (IM). Indeed, the performance of the MRAS depends mainly on the operating point and the parametric variation of the IM. Hence, the sliding mode control (SMC) could be considered a good control alternative...
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On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
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Electrical measurement data for SOFC fueled by H2 and biogas mixture at 750 C
Open Research DataThe dataset contains the Electrical measurement data for SOFC fueled by H2 (30h) and biogas mixture at 750 C (60:40 CH4:CO2). The investigation of long-term electrical stability was performed during initial SOFC feeding with hydrogen (for 30 h) and further with biogas (for 90 h). The electrical properties of the fuel cell were measured using the HAMEG...
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Probabilistic estimation of diverse soil condition impact on vertical axis tank deformation
PublicationThe calculations of fuel tanks should take into account the geometric imperfections of the structure as well as the variability of the material parameters of the foundation. The deformation of the tank shell can have a significant impact on the limit state of the structure and its operating conditions. The paper presents a probabilistic analysis of a vertical-axis, floating-roof cylindrical shell of a tank with a capacity of 50000...
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S7-DK7 Myślenice Zakopane 2017 - video data
Open Research DataThe video cameras installed on the Expressway S7: 6 cameras in both directions, location: main road registered vehicles along the entire length of the road section. Cameras were mounted on 5-7 meter high masts. Date 11-15.08.2017
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Structure, Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams
PublicationIn this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of...
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Cross-layer integration of network mechanisms for increasing efficiency of multimedia session support in IEEE 802.11s environment
PublicationWith an IEEE 802.11 wireless networks operating in Point-to-Multipoint mode being the most popular WLAN access technology employed today, it can be expected that a Wireless Mesh Network (WMN) based on the technology can provide significant advantages for such network systems. The IEEE 802.11s standard amendment provides the comprehensive set of mechanisms required to implement and deploy a WMN utilizing this widely popular technology....
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Cleaner energy for sustainable future using hybrid photovoltaics-thermoelectric generators system under non-static conditions using machine learning based control technique
PublicationIn addition to the load demand, the temperature difference between the hot and cold sides of the thermoelectric generator (TEG) module determines the output power for thermoelectric generator systems. Maximum power point tracking (MPPT) control is needed to track the optimal global power point as operating conditions change. The growing use of electricity and the decline in the use of fossil fuels have sparked interest in photovoltaic-TEG...
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The luminescence study ofNaK2Li[Li3SiO4]4:Ce coumpounds.
Open Research DataPhosphors with a rigid and symmetrical structure are urgently needed. The alkali lithosilicate family (A[Li3SiO4]) has been extensively studied with a narrow emission band due to its unique cuboid-coordinated environment and rigid structure. However, here we demonstrate for the first time Ce-doped NaK2Li[Li3SiO4]4 phosphors with a broad emission band,...
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Examining Quality of Hand Segmentation Based on Gaussian Mixture Models
PublicationResults of examination of various implementations of Gaussian mix-ture models are presented in the paper. Two of the implementations belonged to the Intel’s OpenCV 2.4.3 library and utilized Background Subtractor MOG and Background Subtractor MOG2 classes. The third implementation presented in the paper was created by the authors and extended Background Subtractor MOG2 with the possibility of operating on the scaled version of...
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Determination of the minimal critical rotational speeds of the circular saw blades with the quasi-twin resonant frequencies
PublicationTo determine the minimal critical rotational speeds of the circular saw blades is the fundamental aspect of obtaining the range of the rotational operating speeds, by which the circular saw blade can work with required stability. While for the circular saw blades with full-homogeneous bodies the determination of such rotational speeds is the relatively low level of difficulty function, whereas for circular saw blades with more...
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Expedited Re-Design of Multi-Band Passive Microwave Circuits Using Orthogonal Scaling Directions and Gradient-Based Tuning
PublicationGeometry scaling of microwave circuits is an essential but challenging task. In particular, the employment of a given passive structure in a different application area often requires re-adjustment of the operating frequencies/bands while maintaining top performance. Achieving this necessitates utilization of numerical optimization methods. Nonetheless, if the intended frequencies are distant from the ones at the starting point,...
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Krystian Zawadzki dr hab. inż.
PeopleKrystian Zawadzki is associate professor in the Department of Finance at the Faculty of Management and Economics of the Gdańsk University of Technology; member of the Polish Olympic Academy at the Polish Olympic Committee; coordinator of the Stock Exchange School (Warsaw Stock Exchange) in Gdańsk; Head of postgraduate studies "Capital Investments and Personal Finance Management"; member of the audit committee of the sports club...
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Poprawa stanu dynamicznego hydrozespołu. W: [CD-ROM] Materiały konferencyj- ne. Turbiny Wodne - Niezawodność i Ekologia. Gdańdsk, 9 grudnia 2003. Gdańsk: TEW, KKiEM P. Gdań., A&O EXPERT**2003, wykład oraz prezentacja elektroniczna z wykorzyst. Programu Power Point + wydr. 17 s.
PublicationWspółczesna technika pomiarowa coraz częściej wykrywa pojawienie się drgań względnych czopa względem panwi o częstotliwości zbliżonej do 1/2X, wywołanych tak zwanym wirem olejowym. Drgania te w dłuższym okresie czasu prowadzą do zmęczeniowego uszkodzenia powierzchni ślizgowej łożyska a w konsekwencji do awarii łożyska. Jednym ze sposobów eliminacji tych drgań jest zastosowa-nie dociążenia geometrycznego w łożyskach prowadzących...
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The Use of Free Adjustment and Msplit-Estimation for Determination of the Vertical Displacements in Unstable Reference System
PublicationThe problem of the determining of the displacements of engineering objects and their surroundings is the current and important issue in the field of engineering geodesy. Most control measurements are made in relation to reference points (stable points). On the other hand, sometimes it happens that it is not possible perform the measurements with reference to the stable points or identification of stable points is difficult. Therefore,...
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Ewa Klugmann-Radziemska prof. dr hab.
PeopleEwa Klugmann-Radziemska graduated from the University of Gdansk with a degree in physics, and since 1996 has been associated with the Gdansk University of Technology, when she began PhD studies. Currently, he is a professor at the Faculty of Chemistry at the Gdansk University of Technology, since 2006 head of the Department of Chemical Apparatus and Machinery. In the years 2008–2016 she was the Vice-Dean for cooperation and development,...
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A1-S6 Rebielcz Raduńska 2016 - video data
Open Research DataThe video cameras installed on the Expressway S6 and motorway A1: 4 cameras in both directions, location: main road registered vehicles along the entire length of the road section. Cameras were mounted on 5-7 meter high masts. Date 29-31.07.2016
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Historical Wreck Inventory
Open Research DataThe measurement solution results in a point cloud obtained from the Leica P30 laser scanner. Another element is the processing of photos into point clouds with the Zenmuse P1 camera of the unmanned Matrice 300 RTK aircraft. The measurement provides complete geometrical information about the wreck. The measurement took place as part of the Photogrammetry...