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Badanie egoistycznych zachowań stacji w bezprzewodowej sieci LAN wykorzystującej standard IEEE 802.11.
PublicationProtokół IEEE 802.11 wykorzystywany w bezprzewodowych sieciach LAN ułatwia niekooperacyjne zachowania stacji. Od niedawna przedmiotem badań są zachowania egoistyczne, zwiększające udział pasma stacji kosztem innych użytkowników sieci. W pracy przedstawiono kilka egoistycznych ataków przeciwko protokołowi, w tym poprzez rekonfigurację mechanizmu CSMA/CA. Symulacja wybranych scenariuszy pracy sieci pozwoliła ocenić ilościowo efekty...
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Structural investigations of niobium-doped bioactive calcium-phosphate glass-ceramics by means of spectroscopic studies
PublicationSynthetic calcium-phosphate based glasses and glass-ceramics play a crucial role in the development of tissue engineering. These materials have a high biocompatibility with biological analogues, excellent ability to undergo varying degrees of resorbability and due to their non-toxicity and relatively high bioactivity they are commonly used as bone and dental implants. A substantial research effort is devoted to improve synthetic...
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Albumin–Hyaluronan Interactions: Influence of Ionic Composition Probed by Molecular Dynamics
PublicationThe lubrication mechanism in synovial fluid and joints is not yet fully understood. Nevertheless, intermolecular interactions between various neutral and ionic species including large macromolecular systems and simple inorganic ions are the key to understanding the excellent lubrication performance. An important tool for characterizing the intermolecular forces and their structural consequences is molecular dynamics. Albumin...
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Raman investigation of the patina layers on Hungarian copper ingots from a fifteenth century shipwreck
PublicationWe report results of the patina study of underwater archeological finding ofmedieval copper objects performed by means of the Raman and complementary spectroscopic techniques. The objects were found submerged in the sea as cargo part of the ship which sunk in the Gulf of Gdańsk in 1408. The excavated collection consists of 230 oval ingots of the size and mass up to about 60 cm and 18 kg (total of 2 tons), respectively. In the Raman...
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The effect of using jug-type water filters on selected metals concentration in tap water – a case study
PublicationIn this study, the effect of the filtration process on Na, K, Mg, Ca, Fe and Zn concentration in water, using filters from one of the leading European manufacturers, was investigated. The increase in Na (up to 300%) and K concentration (up to 320%) at the beginning of jug filter usage was reported. A decrease in Ca, Fe and Zn concentration was observed. Standard filters remove 80–90% of Mg from tap water at the beginning of the...
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Selektywne chłodzenie mózgu noworodka po niedotlenieniu okołoporodowym. Cześć 3. Hybrydowy system selektywnego chłodzenia mózgu noworodka
PublicationZapoczątkowane brakiem tlenu procesy biochemiczne mają zgubne skutki dla układu nerwowego, w szczególności rozwijającego się. Hipotermia, czyli stan oziębienia poniżej pewnych wartości temperatur, spowalnia znacznie lub całkowicie wyhamowuje poszczególne reakcje, i to leży u podstaw jej własności neuroprotekcyjnych. Powyższe twierdzenie poparte licznymi faktami naukowymi leży u podstaw koncepcji selektywnego chłodzenia mózgu i...
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Dynamic analysis of lightweight structure of the Viaduct Millau in France subjected to the wind fluctuations described by Karman’s and Davenport’s spectrum
PublicationThe article presents numerical simulations for wind impact modelling on the Millau Viaduct structure in France performed with two independent spectrum generation methods. The viaduct's construction in affected by strong forces, as it is situated in the Tarn river's valley. Thus, the loading coming from the wind cannot be modelled, the way it is in case of simple structures as static loading, but as a loading in a form of a spectrum...
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Exploring Mechanism of Corrosion Inhibition of WE43 and AZ31 Alloys by Aqueous Molybdate in Hank’s Solution by Multisine Impedimetric Monitoring
PublicationThe concept of utilizing multisine dynamic electrochemical impedance spectroscopy to monitor effectiveness of a model molybdate inhibitor for AZ31 and WE43 Mg alloys is proposed. The corrosion kinetics and instantaneous values of inhibition efficiency (IE) of molybdate at concentrations up to 150 mM were examined. The inhibitor provides inhibition in Hank’s solution at concentrations starting from ca. 25 mM, with the IE of about...
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Fatigue fracture surface metrology of thin-walled tubular austenitic steel specimens after asynchronous loadings
PublicationThis paper aims to study the effect of asynchronous axial-torsional strain-controlled loading histories on fracture surface behavior of thin-walled tubular X5CrNi18-10 (304/304L) austenitic steel specimens. Tests under pure axial loading and pure torsional loading are also conducted to better segregate the effect of multiaxiality. The fractures surface topographies were examined through the profiles over the entire surface with...
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New, fast and cheap prediction tests for BRCA1 gene mutations identification in clinical samples.
PublicationDespite significant progress in cancer therapy, cancer is still the second cause of mortality in the world. The necessity to make quick therapeutic decisions forces the development of procedures allowing to obtain a reliable result in a quick and unambiguous manner. Currently, detecting predictive mutations, including BRCA1, is the basis for effectively treating advanced breast cancer. Here, we present new insight on gene mutation...
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Mineral Composition of Dietary Supplements-Analytical and Chemometric Approach
PublicationThere is a lack of data on the actual composition and effectiveness of beetroot-based dietary supplements. The research aimed to determine the profile of 22 elements (Na, K, Ca, Mg, P, Fe, As, Se, Zn, Cu, Ag, Co, Ni, Mo, Al, Mn, Sr, Cr, Ba, Li, Pb, Cd) in beetroot and its supplements by the microwave plasma atomic emission spectrometry (MP-AES) method. The analytical procedure was optimised and validated. The composition of both...
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Library Information Skills - Level 1
e-Learning CoursesThe Gdańsk Tech Library offers Library Information Skills e-course to the students enrolled in English-language degree programmes at Gdańsk University of Technology (Gdańsk Tech). It is an obligatory course. There is a test at the end of the e-course. Information skills, or in other words information literacy, means knowing what kind of information a student is looking for, where to find it, how to evaluate, communicate and use...
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THERMAL ANALYSIS AND DESIGN OF HYBRID MICROCHANNEL -MICROJET TEST PROBE
PublicationAccurate control of cooling parameters is required in ever wider range of technical applications. It is known that reducing the flow hydraulic diameter to an increase in the economy of cooling and improves its quality (Mikielewicz and Muszyński 2009). Present study describes research results related to the design and construction of the test stand for hybrid microjet- microchannel cooling modules study, which may be applied in...
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A Pilot Study on Machining Difficult-to-Cut Materials with the Use of Tools Fabricated by SLS Technology
PublicationThe growing use of contemporary materials in various industrial sectors, such as aerospace, automotive, as well as the oil and gas industry, requires appropriate machining methods and tools. Currently, apart from the necessity to obtain high-dimensional and shape accuracy, the efficiency and economic aspects of the selected manufacturing process are equally important, especially when difficult-to-cut materials, such as hard and...
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Selektywne chłodzenie mózgu noworodka po Niedotlenieniu okołoporodowym. Część 1. Medyczne fakty oraz przegląd dostępnych rozwiązań systemów selektywnego chłodzenia mózgu
PublicationMózg ludzki jest organem delikatnym, dlatego tak ważne jest zadbanie o to, aby już w momencie przyjścia na świat noworodek miał zapewnioną, w razie konieczności możliwość minimalizacji uszkodzeń neurologicznych, spowodowanych niedotlenieniem okołoporodowym. Niedotlenienie to w dramatyczny sposób zaburza homeostazę mózgu, który jako organ najbardziej energochłonny potrzebuje najwięcej tlenu. Zapoczątkowane brakiem tlenu procesy...
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Electrical and structural properties of Nb-doped SrTiO3
PublicationNiobium-doped strontium titanate synthesized via conventional solid-state reaction has been studied. Influence of niobium content on the lattice parameters and electrical conductivity has been reported. Various reduction conditions have been investigated. For samples reduced in hydrogen at 1400°C, a transition from thermally activated to metallic behavior has been observed. Maximum electrical conductivity (ca. 55 Scm−1 at 650°C)...
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Conductivity and superconductivity of (Bi,Pb)4Sr3Ca3Cu4Ox glass-ceramics.
PublicationW układzie(Bi,Pb)-Sr-Ca-Cu-O poprzez krystalizację w fazie stałej można wytworzyć materiały o bardzo różnych właściwościach elektrycznych i nadprzewodzących. W zależności od warunków krystalizacji, można wytworzyć nadprzewodnik o temperaturze krytycznej między 8 a 105 st.K lub materiał nie przechodzący do stanu nadprzewodzącego. W pracy pokazano i przedyskutowano wpływ składu fazowego, struktury i mikrostruktury na przewodnictwo...
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Marta Łabuda dr hab. inż.
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Developing a methodology for model tests of floating platforms in a towing tank of low depth
PublicationThe paper presents two ways to mooring model of semi-submersible platform for research in the small depth towing pool. The tested model was made in the likeness of 1:100 Thunder Horse platform moored in the Gulf of Mexico at a depth of 1,920 m. Its mooring system consisted of 16 semi-taut mooring lines (chain-wire-chain) spaced Star-shape and attached at the bottom to the suction piles. The tests were performed in the towing pool...
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Air-cooled photovoltaic roof tile as an example of the BIPVT system – An experimental study on the energy and exergy performance
PublicationThe air-cooled photovoltaic tile is a subject of presented investigations, which focused on improving the overall system efficiency of PV tiles with heat recovery. The operational efficiency of a PV roof tile, together with the construction optimising the air cooling efficiency, were the main points of plans realized at this research stage. The article describes the experimental research consisting of the assessment of electrical,...
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Elemental composition of deposited sediments - Warszawska/Havla tram-route junction (2024 May)
Open Research DataThis data set contains the elemental composition results of deposited sediments collected at the tram-route junction in Gdańsk. Samples collected after fifteen months of operation of tram line.
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ZnO-decorated green-synthesized multi-doped carbon dots from Chlorella pyrenoidosa for sustainable photocatalytic carbamazepine degradation
PublicationThe promising green synthesis of carbon dots (CDs) from microalga Chlorella pyrenoidosa was achieved using simple hydrothermal and microwave-assisted methods. Doping of nanomaterials by nonmetals (N, S, and P) was confirmed by X-ray photoelectron spectroscopy (XPS), while the existence of metals in the CDs was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM),...
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Electro-photoluminescence in organics
PublicationElektro-fotoluminescencję zaobserwowano w układzie ITO(+)/emiter/Ca(-), gdzie emiter wzbudzany światłem UV (350nm) zawierał dendrymer aminowy m-MTDATA, pochodną fenantroliny BPT i organiczny kompleks platyny PtL2Cl. Widmo fotoluminescencji pochodzi od singletowych ekscypleksów m-MTDATA:BPT i trypletowych ekscypleksów m-MTDATA:PtL2Cl. Ze wzrostem pola elektrycznego następuje wygaszanie ekscypleksów na skutek ich dysocjacji na nośniki...
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Wytwarzanie cząstek węglanu wapnia w układzie gaz-ciecz w obecności substancji organicznych
PublicationOtrzymywano węgaln wapnia w reakcji CO2 z Ca(OH)2. Do mieszaniny reakcyjnej dodawano glikol etylenowy, glicerol lun n-butanol. Cząstki węglanu wapnia strącane w obecności substancji organicznych były mniejsze niz powstałe w wyniku procesu prowadzonego tylko w mieszninie reagentów w wodzie. Najmniejsze cząstki CaCO3 otrzymywano w obecności glicerolu, wówczas średnia średnica cząstek wynosiła 3,1x10^-3 mm dla reakcji prowadzonej...
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Decahedral-shaped anatase titania photocatalyst particles: Synthesis in a newly developed coaxial-flow gas-phase reactor
PublicationDecahedral-shaped anatase particles (DAPs) were prepared by a gas-phase process consisting of titanium(IV) chloride oxidation. The use of a coaxial-flow gas-phase reactor resulted in high reaction yield (ca. 70%) and good reproducibility of DAPs production. The influence of controlled and resultant preparation parameters on the process course and on DAPs properties (such as specific surface area, particle size and particle morphology)...
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Organic electroluminescent devices containing phosphorescent molecules in molecularly doped hole transporting layer.
PublicationW pracy opisano mechanizm świecenia diody dwuwarstwowej diody elektroluminescencyjnej (EL) o zewnętrznej kwantowej wydajności świecenia osiągającej 9% fot./elektron. Warstwę transportującą elektrony tworzyła pochodna osadiazolu (PBD) otrzymana metodąnaparowania próżniowego. Warstwę transportującą dziury uzyskano przez wylanie roztworu poliwęglanu(PC), dendrymeru aminowego m-MTDATAoraz fosforyzującego kompleksu irydu Ir(ppy)3 i...
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The structure of dimethylsulfoxide-solvated magnesium and calcium ions in solution and the solid state, and overview of the coordination chemistry of hydrated and solvated alkaline earth metal ions
PublicationOznaczono strukturę w stanie stałym i ciekłym solwatowanych jonów magnezu i wapnia w dimetylosulfotlenku. Stwierdzono, ze jony te tworzą sześciokoordynacyjne solwaty ze średnią długością wiązań Mg-O i Ca-O 2.062(4) i 2.303(5)A. Przegląd literaturowy ukazał, że jony berylu i magnezu we wszystkich rozpuszczalnikach tworzą odpowiednio cztero- i sześciokoordynacyjne solwaty, podczas gdy jony wapnia i strontu istnieją jako ośmiokoordynacyjne...
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CaO-based high temperature CO2 sorbents – Literature review
PublicationThe use of CaO-based adsorbents has a high potential to capture CO2 from various systems due to its high reactivity with CO2, high capacity, and low cost of naturally derived CaO. The application of CaO-based sorbents to remove carbon dioxide is based on a reversible reaction between CaO and CO2. However, multiple carbonation/calcination cycles lead to a rapid reduction in the sorption capacity of natural CaO, and therefore efforts...
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Co-gasification of waste biomass-low grade coal mix using downdraft gasifier coupled with dual-fuel engine system: Multi-objective optimization with hybrid approach using RSM and Grey Wolf Optimizer
PublicationThe looming global crisis over increasing greenhouse gases and rapid depletion of fossil fuels are the motivation factors for researchers to search for alternative fuels. There is a need for more sustainable and less polluting fuels for internal combustion engines. Biomass offers significant potential as a feed material for gasification to produce gaseous fuel. It is carbon neutral, versatile, and abundant on earth. The present...
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Seasonal and spatial differences in metal and metalloid concentrations in the snow cover of Hansbreen, Svalbard
PublicationMetals and metalloids in snow on glaciers, depending on the season of deposition, may come from various sources: local rock dust (erosion of the geological substratum), marine aerosol, local human activity (e.g. fuel combustion, waste incineration) and long-range atmospheric transport. Hansbreen glacier, located close to the Polish Polar Station in Svalbard, is a perfect site to study metals and metalloids: it has complex geological...
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Design, synthesis and high antitumor potential of new unsymmetrical bisacridine derivatives towards human solid tumors, specifically pancreatic cancers and their unique ability to stabilize DNA G-quadruplexes
PublicationNew promising unsymmetrical bisacridine derivatives (UAs), have been developed. Three groupsincluding 36 compounds were synthesized by the condensation of 4-nitro or 4-methylacridinone, imi-dazoacridinone and triazoloacridinone derivatives with 1-nitroacridine compounds linked with anaminoalkyl chain. Cytotoxicity screening revealed the high potency of these compounds against severaltumor cell lines. Particularly, imidazoacridinone-1-nitroacridine...
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Effects of Micro-Arc Oxidation Process Parameters on Characteristics of Calcium-Phosphate Containing Oxide Layers on the Selective Laser Melted Ti13Zr13Nb Alloy
PublicationTitania-based films on selective laser melted Ti13Zr13Nb have been formed by micro-arc oxidation (MAO) at different process parameters (voltage, current, processing time) in order to evaluate the impact of MAO process parameters in calcium and phosphate (Ca + P) containing electrolyte on surface characteristic, early-stage bioactivity, nanomechanical properties, and adhesion between the oxide coatings and substrate. The surface...
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Spatial variability of the hydrochemistry of shallow groundwaters and surface waters of the Rensdyrbekken: A case study of a permafrost catchment in Bellsund (SW Spitsbergen, Svalbard)
PublicationProgressive climate change may have unpredictable consequences for the Arctic environment. Permafrost catchments off the west coast of Svalbard, described as “thin” and “warm,” are particularly sensitive to climate change. The interdisciplinary research on the hydrochemical response of surface and underground water functioning within a small permafrost catchment area focused on the determination of the impact of meteorological...
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Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
PublicationSodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between...
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Mono- and bimetallic (Pt/Cu) titanium(IV) oxide core–shell photocatalysts with UV/Vis light activity and magnetic separability
PublicationTitanium(IV) oxide is one of the most widely investigated photocatalysts. However, separation of nano-sized particulate titania might result in profitless technologies for commercial applications. Additionally, bare titania is almost inactive under the Vis range of solar spectrum due to its wide bandgap. Therefore, the present study aims to prepare novel coreinterlayer- shell TiO2 magnetic photocatalysts modified with metal nanoparticles...
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Conductivity and superconductivity in granular materials
PublicationMetale i nadprzewodniki granulaste są bardzo ciekawymi materiałami dzięki jednoczesnej obecności oddziaływań kulombowskich, tunelowania elektronów i par Coopera oraz różnych zjawisk związanych z nieuporządkowaniem. W pracy przedstawiono i porównano niektóre właściwości granulastych nisko- i wysokotemperaturowych nadprzewodników. Granulasty nadprzewodnik wysokotemperaturowy otrzymano metodą krystalizacji w fazie stałej szkła (Bi,Pb)-Sr-Ca-Cu-O....
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Dipodal Tetraamide Derivatives of 1,10-Diaza-18-Crown-6 and Alkylmalonic Acids—Synthesis and Use as Ionophores in Ion Selective Membrane Electrodes
PublicationNovel dipodal derivatives of an 18-membered diaza-crown ether with two diamide chains featuring methylmalonic or butylmalonic acid residues were obtained and tested as ionophores in ion-selective plasticized membrane electrodes. The objective of the study was to identify measurement conditions which ensure the most favorable performance for magnesium ion-selective electrodes. The relationship between the molar lipophilic anion...
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Validation of lumbar spine finite element model
Open Research DataThe functional biomechanics of the lumbar spine have been better understood by finite element method (FEM) simulations. However, there are still areas where the behavior of soft tissues can be better modeled or described in a different way. The purpose of this research is to develop and validate a lumbar spine section intended for biomechanical research....
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The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition
PublicationThe superionic α ↔ β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and measurements of Seebeck coefficient and electrical conductivity. Results of the DSC measurements with 1–10 K/min heating and cooling rates show that the material is close to the equilibrium phase composition during the transformation. However, the kinetic limitation of the process exists, which is indicated...
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
PublicationThe paper studies the effect of strain-loading sequence on fatigue lifetime and fracture surface topographies in 7075-T651 aluminum alloy specimens. Fatigue tests were performed in two ways: (i) constant-amplitude loading and (ii) two series of variable amplitude loading with non-zero mean strain values. The topography of the fatigue fractures was measured over their entire surfaces with the help of an optical confocal measurement...
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Brain, unspecified - Male, 68 - Tissue image [41207300228971]
Open Research DataThis is the histopathological image of BRAIN tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Brain, unspecified - Male, 68 - Tissue image [4120730022895011]
Open Research DataThis is the histopathological image of BRAIN tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Brain, unspecified - Male, 25 - Tissue image [9270729565542701]
Open Research DataThis is the histopathological image of BRAIN tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Plexiform neurofibroma - Male, 60 - Tissue image [9020730024819611]
Open Research DataThis is the histopathological image of BRAIN tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Brain, unspecified - Male, 68 - Tissue image [412073002289751]
Open Research DataThis is the histopathological image of BRAIN tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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The luminescence study of Ca14Zn6Ga10−xMnxO35 coumpounds.
Open Research DataManganese in the pentavalent state (Mn 5+) is both rare and central in materials exhibiting narrow-band near-infrared (NIR) emission and is highly sought after for phosphor-converted light-emitting diodes as promising candidates for future miniature solid-state NIR light source. We develop the Ca 14 Zn 6 Ga 10−x Mn x O 35 (x = 0.3, 0.5, 1.0, 1.25, 1.5,...
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Application of multi-criteria method to assess the usefulness of a hydrotechnical object for floating housing
PublicationThis publication presents the analysis of three hydrotechnical objects located in the Municipality of Gdańsk with a view of mooring Floating Houses. The assessment of the adaptation of a hydrotechnical object has been carried out by a multi- criteria method AHP and using the main criteria such as: mooring system, communication with the mainland, availability of the utility networks, waste disposal and location of the parking spaces....
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Simulation-Based Approach to a More Efficient Handling Strategy for a Container Terminal Storage Yard: Case Study of the Baltic Hub Container Terminal
PublicationThe primary objective of this research was to implement a more efficient handling strategy in the container terminal storage yard at the Baltic Hub Container Terminal (BHCT). Following an analysis of the current logistics system associated with starboard-side mooring, an attempt was made to shift the mooring to the port side. Two routing strategies corresponding to the analysed mooring operations were tested using a developed...
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Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue
PublicationThis paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and...
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Flow visualization and heat transfer investigations on the flat plate with streamwise pressure gradient
PublicationPaper presents experimental investigations results for film cooling on a flat plate. The main objective of the design is the streamwise pressure distribution on the flat plate as in the blade cascade. The transient and steady-state technique with liquid crystals for the surface temperature distribution with film cooling has been used in experiments in a low speed wind tunnel.