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Wyniki wyszukiwania dla: MECHANICAL STRESSES IN ENCLOSURES
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Effect of Laser Treatment on Intrinsic Mechanical Stresses in Titanium and Some of Its Alloys
PublikacjaLaser surface treatment conducted at different power levels is an option to modify titanium bone implants to produce nano- and microtopography. However, such processing can lead to excess mechanical stress within the surface layer. This research aims to calculate the level of such residual stresses after the surface processing of Ti grade IV, Ti15Mo, and Ti6Al7Nb alloys with an Nd:YAG laser. Light and scanning electron microscopies...
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Influence of Surface Laser Treatment on Mechanical Properties and Residual Stresses of Titanium and its Alloys
PublikacjaSurface modification of the titanium and its alloys used in implantology with a long-pulse laser can change the surface topography, but it also leads to changes in the stress sign and magnitude in the resulting subsurface layer. The presented research was aimed at evaluating the state of stress after laser remelting with the Nd:YAG laser of pre-etched titanium alloys Ti6Al4V and Ti13Nb13Zr and pure titanium. The obtained surface...
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Wire Arc Additive Manufactured Mild Steel and Austenitic Stainless Steel Components: Microstructure, Mechanical Properties and Residual Stresses
PublikacjaWire arc additive manufacturing (WAAM) is an additive manufacturing process based on the arc welding process in which wire is melted by an electric arc and deposited layer by layer. Due to the cost and rate benefits over powder-based additive manufacturing technologies and other alternative heat sources such as laser and electron beams, the process is currently receiving much attention in the industrial production sector. The gas...
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P92 steel and inconel 617 alloy welds joint produced using ERNiCr-3 filler with GTAW process: Solidification mechanism, microstructure, mechanical properties and residual stresses
PublikacjaThe objective of the current study was to analyse the microstructure, mechanical characteristics, and residual stresses of a dissimilar welded joint (DWJ) made of P92 steel and the Inconel alloy 617 (IN617) using the gas tungsten arc welding (GTAW) method. The ERNiCr-3 filler was selected to produce the conventional V groove (VG) and narrow V groove (NVG) butt joint. The filler deficient zones in the weldments, such as the filler...
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Karol Niklas dr hab. inż.
OsobyKarol NIKLAS jest profesorem Politechniki Gdańskiej (Wydział Inżynierii Mechanicznej i Okrętownictwa, Instytut Budowy Okrętów). Pracę dyplomową magisterską na kierunku "Budowy okrętów morskich" w specjalności "Budowa małych statków i jachtów" obronił w 2007 roku. W 2008 roku ukończył studia podyplomowe w specjalności "Nowoczesne Metody Symulacyjne w Technice" na Wydziale Fizyki i Matematyki Stosowanej. W 2014 roku obronił rozprawę...
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Rozkład naprężeń mechanicznych w łyżce o szerokości 500 mm, przeznaczonej do koparki podsiębiernej
PublikacjaW artykule zaprezentowano optymalizację kształtu łyżki koparki przedsiębiernej z wykorzystaniem analizy wytrzymałościowej. Analizę oparto na trójwymiarowym modelu konstrukcji łyżki z zastosowaniem metody elementów skończonych (MES). Opracowanie wspomnianej metody pozwoliło na modyfikację konstrukcji łyżki, która dała w efekcie obniżenie naprężeń złożonych w newralgicznych obszarach konstrukcji łyżki. Przedstawiona analiza okazała...
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Kazimierz Darowicki prof. dr hab. inż.
OsobyStudia wyższe ukończyłem w czerwcu 1981 roku po zdaniu egzaminu dyplomowego i obronie pracy magisterskiej. Opiekunem pracy magisterskiej był dr hab. inż. Tadeusz Szauer. W roku 1991, 27 listopada uzyskałem stopień naukowy broniąc pracę doktorską zatytułowaną „Symulacyjna i korelacyjna analiza widm immitancyjnych inhibitowanej reakcji elektrodowej”. Promotorem pracy był prof. dr hab. inż. Józef Kubicki (Wydział Chemiczny...
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Mechanical Strength of MV Ship-switchgear During Fault Arc
PublikacjaIn the paper the analysis of pressure stressed in enclosure during fault arc inside switchgear is pre-sented as well. There is introduced the method based on determining stresses which are sum of tensile stresses (membrane) and deflection stresses. For tensile stresses nalysis the energy method, for unrestrainedly supported rectangular plate, was used. In the further part of the paper, the calculations and measurements results...
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Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp: Phosphorus dynamics
PublikacjaThis is the third paper of the series about “Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp”. In this paper, phosphorus dynamics were investigated under the condition of culturing bighead carp and common carp with added fish food (nitrogen dynamics is discussed in the second paper because their behaviors are so different from each other). Nearly fifty days’ observation results...
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Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid
PublikacjaPaper presents the results of a rheological test of a commercial magnetorheological (MR) fluid (MRF-132DG). The researchincludes the problem of measuring and interpreting limit stresses under conditions close to the magnetic saturation of the fluid. Fourdifferent limit stresses were determined, two related to the yield point and two related to the flow point. Methods for determining limitstresses, especially due to excitation...
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Bending of a Three-Layered Plate with Surface Stresses
PublikacjaWe discuss here the bending deformations of a three-layered plate taking into account surface and interfacial stresses. The first-order shear deformation plate theory and the Gurtin-Murdoch model of surface stresses will be considered and the formulae for stiffness parameters of the plate are derived. Their dependence on surface elastic moduli will be analyzed.
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Computational analysis of power-law fluids for convective heat transfer in permeable enclosures using Darcy effects
PublikacjaNatural convection is a complex environmental phenomenon that typically occurs in engineering settings in porous structures. Shear thinning or shear thickening fuids are characteristics of power-law fuids, which are non-Newtonian in nature and fnd wide-ranging uses in various industrial processes. Non-Newtonian fuid fow in porous media is a difcult problem with important consequences for energy systems and heat transfer. In this...
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Comparison of calculated and measured thermal stresses in asphalt concrete
PublikacjaThe paper presents the comparison of calculated and measured thermal stresses induced in restrained asphalt concrete specimens by cooling. Thermal stresses were measured in the Thermal Stress Restrained Specimen Test. The calculations of thermal stresses were performed with the use of a theoretical formula based on the temperature dependent stiffness modulus. The novel approach applied in this paper was that the stiffness modulus...
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Microstructure and residual stresses in surface coatings with PTFE reservoirs
PublikacjaThe paper presents the results of experimental study into the microstructure and changes in residual stresses resulting from sliding and rolling/sliding loaded interaction between metallic surface coatings with embedded PTFE reservoirs and various counter faces. It was found that before testing surface coatings had compressive residual stresses. Molybdenum coating with all types of PTFE reservoirs displayed, as a result of testing,...
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Contemporary directions of development in mechanical engineering
Kursy OnlinePresentation of new ways of development of different specialisations belonging to mechanical engineering
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Influence of geometrical imperfections on stresses in cylindrical shells
PublikacjaResults of the numerical analysis of the shells of storage tanks of 50 000 m3 capacity with geometrical imperfections are presented in the paper. Results were verified by tensometric tests performed on the real tank. It was recognized that real geometrical imperfections cause increase of stresses in the tank construction by 30%.
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Archives of Civil and Mechanical Engineering
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On stress singularity near the tip of a crack with surface stresses
PublikacjaIn the framework of the simplified linear Gurtin–Murdoch surface elasticity we discuss a singularity of stresses and displacements in the vicinity of a mode III crack. We show that inhomogeneity in surface elastic properties may significantly affect the solution and to change the order of singularity. We also demonstrate that implicitly or explicitly assumed symmetry of the problem may also lead to changes in solutions. Considering...
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Evaluation of Thermal Stresses in Asphalt Layers in Comparison with TSRST Test Results
PublikacjaThe paper presents the results of calculations and laboratory determination of thermal stresses at low temperatures. The modified Hills and Brien's method was used to calculate the thermal stresses in asphalt layers of pavements and the results were compared against the values obtained at a laboratory with the Thermal Stress Restrained Specimen Test (TSRST) method. The laboratory investigations were conducted using plain grade...
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Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table
PublikacjaTheoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important...
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On Nonlinear Dynamic Theory of Thin Plates with Surface Stresses
PublikacjaWe discuss the modelling of dynamics of thin plates considering surface stresses according to Gurtin–Murdoch surface elasticity. Taking into account the surface mass density we derive the two-dimensional (2D) equations of motion. For the reduction of the three-dimensional (3D) motion equations to the 2D ones we use the trough-the-thickness integration procedure. As a result, the 2D dynamic parameters of the plate depend not only...
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MECHANICAL SYSTEMS AND SIGNAL PROCESSING
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The Influence of Modelling Material Zones on Strains and Stresses at Weld Toe Notch
PublikacjaThe latest development in the field of welding technology enabled prefabrication of thin-walled sandwich structures in an industrial scale. Sandwich structures fabricated of steel, or aluminium alloy plates and stiffeners are welded with the use of hi-power CO2 lasers. Strength analysis of such structures with the use of finite element method needs proper material modelling.In this paper the material model of steel sandwich panel...
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Application of Barkhausen method to determine internal stresses in cold-rolled and hot-rolled sheets
PublikacjaThe paper presents investigations on internal stress distribution in plane hot—or cold-rolled sheets dedicated for the cold-formed profiles. The motivation of the research is a new profile design whose bending technology, incorporating a longitudinal welded joint and hot-dip galvanization after bending and welding introduces additional internal stresses. In order to identify the entirety of stresses in the process of sheet production...
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Effects of CO2 and Nd:YAG Laser Remelting of the Ti6Al4V Alloy on the Surface Quality and Residual Stresses
PublikacjaThe titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level...
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Sawing Processes as a Way of Determining Fracture Toughness and Shear Yield Stresses of Wood
PublikacjaA new computational model, based on fracture mechanics, was used to determine cutting forces. Unlike traditional computing methods, which depend on many coefficients reflecting the machining of solid wood, the new model uses two main parameters: fracture toughness and shear yield stresses. The aim of this study was to apply this new method to determine these parameters for the tooth cutting edge principal positions and longitudinal...
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Archive of Mechanical Engineering
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The Influence of Impact Velocity on Stresses and Failure of S355j2 Steel Under Slurry Erosion Conditions
PublikacjaThe purpose of this work was to determine the essence of the influence of the impact velocity (5, 7, and 9 m/s) on Hertzian stresses and the erosion mechanism of ferritic-pearlitic S355J2 steel. The investigations were carried out using a slurry pot tester. S355J2 steel showed a strong sensitivity to changes in impact velocity. A significant increase in erosion rate was observed at a velocity of 9 m/s. This increase was 5-fold...
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Analysis of Residual Stresses and Dislocation Density of AA6082 Butt Welds Produced by Friction Sir Welding
PublikacjaThe Friction Stir Welding (FSW) method was employed to join AA6082 sheets. The welds were produced with different tool traverse speed (200 and 250 mm/min), rotational speed (1000 and 1250 RPM) and tool tilt angle (0 and 2 deg). Based on the analysis of XRD patterns, the total precipitation volume fractions in the nugget zones and the base material were calculated. The FSW process resulted in a reduction in the fraction of precipitates...
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Electronics for Mechanical Engineering (2023)
Kursy OnlineName of the course: Electronics (M:32011W0)Specialization: Design and Production Engineering (WM), 1st degree - bachelor/eng., stationary, 2018/2019 - winter semester (currently sem. 4) Number of hours: 30hECTS points: 2 Teacher (lecture/laboratories): Piotr Kurgan
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Electronics for Mechanical Engineering (2024)
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A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements
PublikacjaThe paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally...
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Mechanical, thermo-mechanical properties of epoxy/glass composites with submicron particles
PublikacjaIn this research the influence of submicron zinc oxide and silicon dioxide particles on mechanical, thermo-mechanical properties of epoxy matrix composites reinforced with glass fibres was investigated. Composites were fabricated using hand lay-up method. Materials contained 39-41 wt.% of glass fibres. The bending tests, dynamic mechanical analysis and tribological tests were performed on each group of composites and also for...
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Modeling of the Two-Dimensional Flow Caused by Sea Conditions and Wind Stresses on the Example of Dead Vistula
PublikacjaThe article presents the results of two-dimensional modeling of flows caused by the sea conditions and wind stresses on the example of Dead Vistula. Based on the available bathymetric data, a numerical model of the river section was created, which was supplemented with data on the position of the water table depending on hydrometeorological conditions. To describe the flow field in steady conditions, a simplified model of two-dimensional...
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Dariusz Mikielewicz prof. dr hab. inż.
OsobyDariusz Mikielewicz – urodził się 6 lutego 1967 roku w Gdańsku, w 1985r. zdał pomyślnie egzaminy wstępne na Wydział Budowy Maszyn Politechniki Gdańskiej, który ukończył z wynikiem bardzo dobrym w 1990 roku na specjalności Maszyny i Urządzenia Energetyczne. Zainteresowania pracą naukową skłoniły go do podjęcia badań na University of Manchester na wydziale mechanicznym i energetyki jądrowej (Mechanical and Nuclear Engineering Department)...
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Examination of selected failure criteria with asymmetric shear stresses in the collapse analysis of laminated shells
PublikacjaThe paper is concerned with failure analysis of composite shells performed with the usage of the nonlinear 6‐parameter shell theory with drilling rotation degree of freedom. This special theory embodies naturally unlim-ited translations and rotations and is suitable for analysis of irregular shells for instance with various, partic-ularly orthogonal, intersections. The presence of the drilling rotation is inherently accompanied...
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Adam Dąbrowski dr inż.
OsobyAdam Dąbrowski uzyskał stopień doktora nauk inżynieryjno-technicznych w dyscyplinie inżynieria mechaniczna na Politechnice Gdańskiej oraz ukończył studia II stopnia na kierunku mechatronika na Technische Universität Hamburg a także double degree Engineering and Management of Space Systems na Hochschule Bremen. Posiada doświadczenie przemysłowe (Instytut Lotnictwa w Warszawie, SICK AG w Hamburgu, Blue Dot Solutions w Gdańsku, Niemieckie...
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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublikacjaThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Mechanics and Mechanical Engineering
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Biological and mechanical properties of bone cement with nanoarticles - in vitro and in vivo research
PublikacjaDespite antibiotic preventive treatment both before and after implant implementation, the risks of infection are real. These infections develop at the implant surface a few months after inserting them into the body. To prevent the development of bacteria and reduce the risk of infection, implants coated with nanoparticles are used. The Mechanical Department of the Technical University of Gdansk carries out research into using bone...
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Effect of Porosity on the Thermo-Mechanical Behavior of Friction-Stir-Welded Spark-Plasma-Sintered Aluminum Matrix Composites with Bimodal Micro- and Nano-Sized Reinforcing Al2O3 Particles
PublikacjaThe thermo-mechanical behavior of nanosized Al2O3 particles reinforcing aluminum was analyzed in the present paper. The material was prepared by spark plasma sintering and friction stir welding. The thermal stresses affecting the composite behavior during welding were modeled through COMSOL MultiPhysics, and the results were validated by the analyses of the composites’ mechanical properties. The spark-plasma-sintered materials...
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Influence of selected submicron inorganic particles on mechanical and thermo-mechanical properties of unsaturated polyester/glass composites
PublikacjaIn this paper, the influence of different submicron-scaled particles (zinc oxide, titanium dioxide, or silica) on mechanical and thermo-mechanical properties of unsaturated polyester matrix composites reinforced with glass fabric was investigated. Surface morphology of obtained composites was also examined. At first inorganic particles were mechanically dispersed into unsaturated polyester resin system as per the calculated weight...
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Application and mechanical properties of aluminium alloys
PublikacjaThe paper presents a short survey of the application and mechanical properties of aluminium alloys. This area of scientific research is still developing, the authors restricted it to about 30 papers. Numerical simulations of the aluminium bracket are also investigated. The authors propose a solution to increase the load capacity of aluminium brackets with application of the additional cover plates. This study is proposed as an...
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The effect of tensile stresses on aluminium passive layer durability
PublikacjaW niniejszej pracy przedstawiono wyniki badań DEIS dotyczących wpływu naprężeń rozciągających na trwałość warstwy pasywnej aluminium A91050, prowadzonych w środowisku chlorków w temperaturze pokojowej.Zastosowana technika pozwoliła na wyznaczenie krytycznej wartości wydłużenia, przy której doszło do pęknięcia warstwy pasywnej na badanym stopie.
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Mechanical testing of technical woven fabrics
PublikacjaThis article presents a review of technical fabrics testing methods used by the authors on the basis of their experience with research on properties of polytetrefluoroethylene-coated fabrics used for Forest Opera in Sopot (Poland). First, the different types of testing methods used for description of mechanical properties (uniaxial tensile tests, biaxial tensile tests and shear tests) of technical woven fabrics are described. The...
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Mechanical response of human thoracic spine ligaments under quasi-static loading: An experimental study
PublikacjaPurpose This study aimed to investigate the geometrical and mechanical properties of human thoracic spine ligaments subjected to uniaxial quasi-static tensile test. Methods Four human thoracic spines, obtained through a body donation program, were utilized for the study. The anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), capsular ligament (CL), ligamenta flava (LF), and the interspinous ligament and...
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SHEAR YIELD STRESSES AND FRACTURE TOUGHNESS OF SCOTS PINE (PINUS SYLVESTRIS L.) ACCORDING TO THE RAW MATERIAL PROVENANCE
PublikacjaIn this paper values of the fracture toughness and of shear yield stress in the shear zone of Scots pine are presented. Tests of cutting were carried on samples of Scotch pine (Pinus sylvestris L.) wood of five provenances from Poland. These experimentally cutting tests were carried on the sash gang saw PRW-15M and the values of cutting power were obtained. The values of fracture toughness and shear yield stress based on Atkins’s...
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Mechanical and thermo-mechanical properties of natural rubber composites filled with submicron- and nano-sized silica particles and prepared using glycolysate as a plasticizer
PublikacjaThe main aim of this work was to examine the selected mechanical and thermo-mechanical properties of natural rubber/silica composites prepared using glycolysate as a plasticizer. Prepared composites contained different amounts of submicron- (10, 15, 20 or 25 pphr) or nano-particles (0.5, 0.75, 1.0 or 1.25 pphr). The tensile properties, tear resistance, hardness, abrasion resistance and resilience of prepared materials were determined....
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Marek Krawczuk prof. dr hab. inż.
OsobyKariera naukowa 1987 mgr inż. - absolwent Wydziału Mechanicznego PG 1991 dr inz. - Instytut Maszyn Przepływowych PAN 1995 dr hab. inż. - Instytut Maszyn Przepływowych PAN 2003 prof - Instytut Maszyn Przepływowych PAN Zatrudnienie 1987-89 Politechnika Gdańsk 1989-2007 Instytut Maszyn Przepływowych PAN w Gdańsku 2001-2003 Uniwersytet Warmińsko-Mazurski w Olsztynie 2003 - Politechnika Gdańska
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Contribution of Exogenous Proline to Abiotic Stresses Tolerance in Plants: A Review
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