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Wyniki wyszukiwania dla: STRUCTURAL HEALTH MONITORING, INVERSE PROBLEM, SNOW LOAD, SAFETY OF THE STRUCTURE, FEM MODEL
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Assessment of tensile forces in Sopot Forest Opera membrane by in situ measurements and iterative numerical strategy for inverse problem
PublikacjaAssessment of tensile forces in newly build Sopot Forest Opera roofing membrane is presented. The procedure is based on in situ measurements and solution of the inverse problem by an iterative procedure. The goal of the analysis is to determine whether the stress state of the membrane is consistent with the design assumptions. The paper contains the description of measurements, used instruments, applied loadings, numerical investiga-tions...
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SHM System of the Roof Structure of Sports Arena “Olivia”
PublikacjaThe paper presents a structural health monitoring system of the Sports Arena “Olivia” in Gdansk, Poland. The system was installed because of doubts about the roof stability due to observed buckling of the steel truss members. The SHM system was based on nonlinear FEM models used for detection of type of near failure modes of the roof. The application of detailed FEM model in current state updated on data from in situ loading testes...
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Road Safety Observatories within the Structure of Integrated Transport Safety Systems
PublikacjaAccurate knowledge about the causes, circumstances and place of transport accidents is the prerequisite to take the correct action to improve transport safety. Developing appropriate organizational structures, forms and methods of management and implementation of safety measures in the sectoral approach condition the success. Therefore the Safety Information System is one of the integral areas of the Integrated Transport Safety...
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IMPLEMENTING THE QUALITY ASSURANCE SYSTEM AND ASSURING HEALTH SAFETY IN THE LIGHT OF INCREASING BREAD QUALITY
PublikacjaThe article presents rules, requirements, and norms for quality management and health safety assurance systems among small and medium bakeries. This group of businesses does not have the obligation of implementing or certifying specific systems. They are, however, implemented in order to increase the quality of the bread or reach a better market position. Also, the results of a 2022 study of 53 bakeries’ implementation of individual...
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Beata Basińska dr hab.
OsobyPsycholożka pracy i organizacji. Jej główne zainteresowania to psychologia zdrowia w pracy (dobrostan i emocje) i pozytywne zachowania organizacyjne. Jest aktywną członkinią the European Academy of Occupational Health Psychology (EAOHP), European Association of Work and Organizational Psychology (EAWOP), European Health Psychology Society (EHPS) i sekcji psychologii zdrowia Polskiego Towarzystwa Psychologicznego (PTP).
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A Novel Versatile Decoupling Structure and Expedited Inverse-Model-Based Re-Design Procedure for Compact Single-and Dual-Band MIMO Antennas
PublikacjaMultiple-input multiple-output (MIMO) antennas are considered to be the key components of fifth generation (5G) mobile communications. One of the challenges pertinent to the design of highly integrated MIMO structures is to minimize the mutual coupling among the antenna elements. The latter arises from two sources, the coupling in the free space and the coupling currents propagating on a ground plane. In this paper, an array of...
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New propagation model for wireless monitoring systems in the container terminal environment
PublikacjaW artykule został poddany analizie problem szacowania tłumienia propagacyjnego na obszarze terminala kontenerowego. Została opisana kampania pomiarowa, której rezultatem było opracowanie nowego modelu propagacyjnego dla łącza radiowego pracującego w warunkach LOS i NLOS.
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Inverse shadowing and related measures
PublikacjaWe 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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Reliability data safety instrumented systems SIS from the functional safety analysis example critical instalation
Dane BadawczeThe dataset represents the results of an example of functional safety analysis systems is presented below. It is based on a control system, which consists of some basic components like sensors, programmable logic controllers and valves. It is a part of petrochemical critical installations. The communication between sensor logic controllers and actuators...
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Numerical Determination of the Load-Bearing Capacity of a Perforated Thin-Walled Beam in a Structural System with a Steel Grating
PublikacjaThis article presents the results of numerical simulations of a structural system consisting of steel perforated thin-walled beams and a steel grating. The simulations were conducted using the finite element method. The analysis took into account physical and geometric nonlinearity as well as the contact between the steel grating and the beams. The main goal of the research was to develop load-bearing curves for the main beam in...
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Computer-Aided Greenery Design—Prototype Green Structure Improving Human Health in Urban Ecosystem
PublikacjaIncreasing population and urbanization, with climate change consequences, such as rising temperatures, influence public health and well-being. The search to improve the quality of life in cities becomes one of the priority objectives. A solution can be found in the role of greenery in an urban environment and its impact on human health. This opens a path toward experimentation on microclimate green structures that can be inserted...
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Design of Structure of Tension Leg Platform for 6 MW Offshore Wind Turbine Based On Fem Analysis
PublikacjaThe article presents the calculation and design stages of the TLP platform serving as a supporting construction of a 6 MW offshore wind turbine. This platform is designed to anchor at sea at a depth of 60 m. The authors presented the method of parameterization and optimization of the hull geometry. For the two selected geometry variants, the load and motion calculations of the platform subjected to wind, wave and current under...
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FEM approach to modeling of an irregular trabecular structure
PublikacjaThe aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the...
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Load-settlement characteristics of piles working in a group
PublikacjaLoad-settlement characteristic (Q-s) of an axially loaded pile can be empirically determined from a static pile load test or on the basis of calculations using, e.g. transfer functions or numerical methods (FEM). The transfer functions method usually rely on empirical data, i.e. the function parameters are determined on the basis of numerous pile test results. Thus this method takes into account pile installation technology and...
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Roof over PGE Arena in Gdansk. Review of structure and monitoring system
PublikacjaThis paper presents general structural assumptions of the steel construction designed for a newfootball stadium to be built for UEFA Championship 2012 in the city of Gdańsk. The superstructureis founded directly on the modified abutment. The facade and the roof are collected from 82 steelgirders made of tube profiles. The girders are braced by circular beams and X tension rods. All thiscreates a quasi - dome covered by polycarbonate...
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2D inverse method of turbomachinery stage design
Publikacja1. How 2D model for turbomachinery stages has developed historically. 2. Recent understanding of physical background of 2D model. 3. Curvilinear system of non-orthogonal coordinates in the application to 2D model. 4. Set of basic equations. 5. Closing conditions for the inverse problem. 6. Examples of solutions a)
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Macro-elements and Model Order Reduction for Efficient Three-Dimensional FEM Analysis
PublikacjaAn efficient model order reduction (MOR) methodology for three dimensional vector finite element method (FEM) is developed to accelerate simulations of the structures containing features that cause strong variations of mesh density. As the result of presented algorithm, FEM subsystems of equations corresponding to the selected refined region are converted into a very compact sets of linear equations, called macro-elements.Numerical...
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JOURNAL OF MOLECULAR STRUCTURE
Czasopisma -
Snow Cover Studies: a Review on the Intensity of Human Pressure
PublikacjaSnow cover should be treated as a highly dynamic medium. A variety of physical and chemical processes interact to alter its chemical composition and affect the metamorphism of its individual crystals and layers; this, in turn, has a direct influence on their mutual adhesion, and ultimately on the stability of the entire snow cover. The literature data here reported provide basic information on the forms of solid precipitation,...
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Efficient model order reduction for FEM analysis of waveguide structures and resonators
PublikacjaAn efficient model order reduction method for three-dimensional Finite Element Method (FEM) analysis of waveguide structures is proposed. The method is based on the Efficient Modal Order Reduction (ENOR) algorithm for creating macro-elements in cascaded subdomains. The resulting macro-elements are represented by very compact submatrices, leading to significant reduction of the overall number of unknowns. The efficiency of the model...
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Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublikacjaUltrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...
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Degree of entaglement as a physically ill-posted problem: The case of entaglement with vacuum
PublikacjaAnalizujemy przypadek fotonu w superpozycji różnych modów i zadajemy pytanie o stopień ich splątania z próżnią. Problem okazuje się być źle postawiony, gdyż nie wiemy którą reprezentację algebry CCR wybrać dla kwantowania pola. Gdy dokonamy wyboru jednoznacznie możemy rozwiązać zagadnienie splątania. Tak więc trudność nie leży w matematyce lecz w fizyce problemu.
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MODEL OF MULTILEVEL STOCHASTIC ANALYSIS OF ROAD SAFETY ON REGIONAL LEVEL
PublikacjaIn this paper multilevel approach to the issue of road safety level on the road network of European regions, classified as NUTS 2 in statistical databases of the European Union, has been presented. Following the pattern of many publications on road safety it has been assumed that the risk calculated as the number of death casualties in road accidents per 100,000 inhabitants of a given region has Poisson distribution. Therefore,...
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Microsphere structure application for supercapacitor in situ temperature monitoring
PublikacjaConstant, real-time temperature monitoring of the supercapacitors for efficient energy usage is in high demand and seems to be crucial for further development of those elements. A fiber-optic sensor can be an effective optoelectronic device dedicated for in-situ temperature monitoring of supercapacitors. In this work, the application of the fiber-optic microstrucutre with thin zinc oxide (ZnO) coating fabricated in the atomic layer...
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Numerical Investigation on Dynamic Performance of a Multi-storey Steel Structure Model and Comparison with Experimental Results
PublikacjaShaking table testing is the most commonly adopted method to simulate earthquake forces. This approach allows us to analyze the dynamic performance and provides a valuable insight into the dynamics of building structures, which helps to improve their future safety and reliability. The present study aims to conduct a numerical evaluation of dynamic response of a multi-storey steel structure model, which was previously examined during...
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Numerical investigation on dynamic performance of a multi-storey steel structure model and comparison with experimental results
PublikacjaShaking table testing is the most commonly adopted method to simulate earthquake forces. This approach allows us to analyze the dynamic performance and provides a valuable insight into the dynamics of building structures, which helps to improve their future safety and reliability. The present study aims to conduct a numerical evaluation of dynamic response of a multi-storey steel structure model, which was previously examined during...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublikacjaThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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ENVIRONMENTAL MONITORING AND ASSESSMENT
Czasopisma -
Three-dimensional geographically weighted inverse regression (3GWR) model for satellite derived bathymetry using Sentinel-2 observations
PublikacjaCurrent trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favourable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment...
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NUMERICAL MODEL QUALITY ASSESSMENT OF OFFSHORE WIND TURBINE SUPPORTING STRUCTURE BASED ON EXPERIMENTAL DATA
PublikacjaAs a structure degrades some changes in its dynamical behavior can be observed, and inversely, observation and evaluation of these dynamical changes of the structure can provide information of structural state of the object. Testing of the real structure, besides of being costly, can cover only limited working states. It is particularly considerable in case of hardly accessible, and randomly/severely dynamically loaded offshore...
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Displacement measurements during load testing of railway arch bridge
PublikacjaThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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NUMERICAL MODEL OF PLASTIC DESTRUCTION OF THICK STEEL STRUCTURAL ELEMENTS
PublikacjaIn the shipbuilding industry, the risk of brittle fracture of the structure is limited by using certified materials with specified impact strength, determined by the Charpy method (for a given design temperature) and by supervising the welding processes (technology qualification, production supervision, non-destructive testing). For off-shore constructions, classical shipbuilding requirements may not be sufficient. Therefore, the...
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Inverse Flood Routing Using Simplified Flow Equations
PublikacjaThe paper considers the problem of inverse flood routing in reservoir operation strategy. The aim of the work is to investigate the possibility of determining the hydrograph at the upstream end based on the hydrograph required at the downstream end using simplified open channel flow models. To accomplish this, the linear kinematic wave equation, the diffusive wave equation and the linear Muskingum equation are considered. To achieve...
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Rapid EM-driven antenna dimension scaling through inverse modeling
PublikacjaIn this letter, a computationally feasible technique for dimension scaling of antenna structures is introduced. The proposed methodology is based on inverse surrogate modeling where the geometry parameters of the antenna structure of interest are explicitly related to the operating frequency. The surrogate model is identified based on a few antenna designs optimized for selected reference frequencies. For the sake of computational...
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APPLICATION OF CHEMOMETRIC ANALYSIS TO THE STUDY OF SNOW AT THE SUDETY MOUNTAINS, POLAND
PublikacjaSnow samples were collected during winter 2011/2012 in three posts in the Western Sudety Mountains (Poland) in 3 consecutive phases of snow cover development, i.e. stabilisation (Feb 1st), growth (Mar 15th) and its ablation (Mar 27th). To maintain a fixed number of samples, each snow profile has been divided into six layers, but hydrochemical indications were made for each 10 cm section of core. The complete data set was subjected...
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Experimental Study of Dapped-End Beams Subjected to Inclined Load
PublikacjaThis paper presents the results of an experimental investigation of the reinforced concrete (RC) dapped-end beams loaded with inclined forces, compared to identical ones loaded with vertical forces only. Such a load may occur in, for example, Gerber's joints or in dapped-end beams supported on corbels, where the vertical gravitation force is additionally completed with horizontal forces caused by temperature differences, shrinking,...
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MONITORING SYSTEM OF THE ROAD EMBANKMENT
PublikacjaThe paper presents the analysis of the monitoring system of the embankment supported on concrete columns and overlaid by a load transfer platform with the embedded steel grid. This field investigation was to study the complex interaction among the columns, the load transfer platform layer, and steel grid via in situ measurements during erection and live loading of the embankment. The study was focused on the behaviour of steel...
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Corrosion monitoring as a factor increasing the safety of hydrotechnical infrastructure
PublikacjaWater distribution systems at KGHM S.A. are of great importance for the efficient production of copper and environmental protection. For failures leading to perforation and leakage, the corrosion processes are responsible. This paper aims to assess corrosion on the basis of the analysis of the exposure of the Hydrotechnical Plant pipelines. To this end, the system of transfer and deposition of post-flotation waste as well as the...
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Reduced model of gyroscopic system
PublikacjaThe paper presents the method of model reduction for the system with gyroscopic interactions. Two methods were used to obtain the approximate discrete models of the continuous structure: the modal decomposition method and the rigid finite element method. The first approach is used for this part of a system for which it is easy to formulate orthogonality conditions, meanwhile the second one is used for other part. The method enables...
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Application of probabilistic tools to extend load test design of bridges prior to opening
PublikacjaLoad tests of bridges are widely performed in a large number of countries. Deterministic comparison of measurement results to the theoretical, FEM (finite element method)-based outcomes with possible further calibration is mostly applied. Sometimes, the data collected in the tests are also used to calibrate the reliability factors of bridge structures or their components. This work proposes to complement the stage of the load test...
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Rapid dimension scaling of triple-band antennas by means of inverse surrogate modeling
PublikacjaGeometry scaling of antennas, i.e., finding optimum dimensions of the structure for given operating conditions and material parameters is an important yet challenging problem. In this paper, we discuss fast dimension scaling of triple-band antennas with respect to operating frequencies. We adopt the inverse surrogate modeling approach where the surrogate model is a function of the three operating frequencies of the antenna and...
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Expedited Geometry Scaling of Compact Microwave Passives by Means of Inverse Surrogate Modeling
PublikacjaIn this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures (i.e., constructed using uniform transmission lines), re-design of miniaturized circuits (e.g., implemented with artificial transmission lines, ATSs) for different operating frequencies is far from being straightforward due to considerable cross-couplings between the circuit components. Here, we...
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Remote Health Monitoring of Wind Turbines Employing Vibroacoustic Transducers and Autoencoders
PublikacjaImplementation of remote monitoring technology for real wind turbine structures designed to detect potential sources of failure is described. An innovative multi-axis contactless acoustic sensor measuring acoustic intensity as well as previously known accelerometers were used for this purpose. Signal processing methods were proposed, including feature extraction and data analysis. Two strategies were examined: Mel Frequency Cepstral...
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Comparison of the Effectiveness of Health Systems in The European Countries-Two-Stage DEA Model
PublikacjaThis article compares the efficiency of health systems in selected European countries using two-stage data envelopment analysis (DEA), based on data from the EUROSTAT database. In the first step, DEA efficiency scores were calculated for health care systems and, subsequently, the external variables describing lifestyle were used to calculate the truncated regression. Health care resources (physicians, nurses, hospital beds, financial...
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Laboratory Load Model Based on 150 kVA Power Frequency Converter and Simulink Real-Time – Concept, mplementation, Experiments
PublikacjaFirst section of the paper provides technical specification of laboratory load model basing on 150 kVA power frequency converter and Simulink Real-Time platform. Assumptions, as well as control algorithm structure is presented. Theoretical considerations based on criteria which load types may be simulated using discussed laboratory setup, are described. As described model contains transformer with thyristor-controlled tap changer,...
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Safety integrity level verification for safety-related functions with security aspects
PublikacjaThe article is devoted some important issues of the functional safety analysis, in particular the safetyintegrity level (SIL) verification of safety functions to be implemented within the distributed controland protection systems with regard to cyber security aspects. The procedure for functional safety man-agement includes hazard identification, risk analysis and assessment, specification of overall safetyrequirements and definition...
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VOF-DEM-FEM combined model of the reef breakwater collapse
PublikacjaZespolony model numeryczny (metoda modelowania przepływu ze swobodną powierzchnią rozdziału faz ciekłej i gazowej w siatce nieruchomej (ang. Volume of Fluid - VOF, metoda elementów dyskretnych (ang. Distinct Element Method, metoda elementów skończonych (MES)) został wykorzystany do zbadania odkształceń falochronu narzutowego i jego piaszczystego podłoża w wyniku oddziaływania falowania powierzchniowego. Wyniki analizy numerycznej...
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Concentration‐Induced Hetero‐Valent Partial‐Inverse Occupation of Infrared Phosphor
PublikacjaInfrared luminescent materials have evoked much attention from chemists and material scientists. Although substantial progress is made in materials design, the luminescent mechanism remains ambiguous in the complex structures, presenting major barriers to developing novel infrared luminescent materials. Herein, this study aims to deliberate a complete discussion on infrared phosphors with concentration-induced hetero-valent partial-inverse...
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Inverse surrogate modeling for low-cost geometry scaling of microwave and antenna structures
PublikacjaPurpose–The purpose of this paper is to investigate strategies for expedited dimension scaling ofelectromagnetic (EM)-simulated microwave and antenna structures, exploiting the concept of variable-fidelity inverse surrogate modeling.Design/methodology/approach–A fast inverse surrogate modeling technique is described fordimension scaling of microwave and antenna structures. The model is established using referencedesigns obtained...
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Janusz Kozak prof. dr hab. inż.
OsobyDr hab. inż. Janusz Kozak Dziekan Wydziału Oceanotechniki i Okrętownictwa Politechniki Gdańskiej Urodzony: 04.07.1953 w Pucku Absolwent Technikum Budowy Okrętów „Conradinum” w Gdańsku, 1973. Absolwent Instytutu Okrętowego PG, 1978. Po ukończeniu studiów praca w Stoczni Gdynia, a od roku 1980 w Katedrze Technologii Okrętów Instytutu Okrętowego a później Wydziału Oceanotechniki i Okrętownictwa Politechniki Gdańskiej kolejno na...