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Wyniki wyszukiwania dla: SINTERED POROUS METALS
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The reductivity of the transition metals - calculations
Dane BadawczeThe dataset includes the reduction enthalpy and Gibbs energy simulated for Co, Cu, Fe, La, Mo, Ni, Sr, Ti, and W from oxide form into metallic form in hydrogen. Simulations were performed using HSC Chemistry software.
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Bonding in Phosphanylphosphinidene Complexes of Transition Metals and their Correlation with Structures, 31 P NMR Spectra, and Reactivities
PublikacjaTheoretical studies of the bonding interactions and most important properties are carried out for isolable phosphanylphosphinidene complexes of transition metals. Three main types of phosphanylphosphinidene complexes are distinguished, based on the way in which the phosphanylphosphinidene ligand bonds to the metal center: (i) side-on complexes of platinum, where the R2Pβ–Pα ligand mimics structural features of free singlet phosphanylphosphinidenes...
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Effect of Different Vacuum Heat Treatments on the Microstructure of a Low Alloyed Sintered Steel
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Corrosion resistance of sintered duplex stainless steels in the salt fog spray test
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The Erosion Resistance and Microstructure Evaluation of Laser Surface Alloyed Sintered Stainless Steels
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INFLUENCE OF BISMUTH CONTENT ON COMPLEX IMMITTANCE CHARACTERISTICS OF PRESSURELESS SINTERED BiNbO4 CERAMICS
PublikacjaGoal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements...
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Plate heat exchanger with porous structure for potential use in ORC system
PublikacjaThe experimental analysis of passive heat transfer intensification in the case of plate heat exchanger has been carried out. The passive intensification was obtained by a modification of the heat transfer surface, which was covered by a metallic porous microlayer. The experiment was accomplished in two stages. In the first stage the commercial stainless steel gasketed plate heat exchanger was investigated, while in the second one...
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Plate heat exchanger with porous structure for potential use in ORC system
PublikacjaThe experimental analysis of passive heat transfer intensification in the case of plate heat exchanger has been carried out. The passive intensification was obtained by a modification of the heat transfer surface, which was covered by a metallic porous microlayer. The experiment was accomplished in two stages. In the first stage the commercial stainless steel gasketed plate heat exchanger was investigated, while in the second one...
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Pre-oxidation of porous ferritic Fe22Cr alloys for lifespan extension at high-temperature
PublikacjaPre-oxidation of porous ferritic Fe22Cr alloys was extensively studied in this paper. Weight gain measurements and SEM analysis revealed that pre-oxidation performed at 900◦C for 40 min increased the lifespan of the alloy. A Cr evaporation study did not disclose any significant influence of the pre-oxidation process on the Cr content in the alloy. For a more detailed assessment, TEM imaging and X-ray tomography measurements of...
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Adam Szymkiewicz prof. dr hab. inż.
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Conducting polymers electrodeposited on active metals
PublikacjaPraca poświęcona studiom literaturowym doniesień dotyczących polimerów przewodzących, osadzanych na metalach aktywnych. Zastosowanie polimerów przewodzących jako warstw antykorozyjnych oraz elektrokrystalizacja metali na polimerach przewodzących zostały zebrane i przedstawione w tej pracy.
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TOLERANCE OF ENVIRONMENTAL BACTERIA TO HEAVY METALS
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Honey as an indicator of heavy metals in the environment
PublikacjaHoney bees collect nectar, pollen and honeydew to produce bee products. One of them is honey, which due to chemical composition and properties is considered by human as a valuable food product. When honey bees collect substrates to produce honey they can bring contaminants to the hive. The presence of xenobiotics in bee products may lower their quality and devalue their properties, and also endanger human health. Many scientists...
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Fabrication, Microstructure and High Temperature Corrosion Resistance of Porous Alloys for Solid Oxide Fuel Cells
PublikacjaPorous alloys find use in modern Solid Oxide Fuel Cells as the supporting structures. As they are exposed to high temperatures (> 500°C) an oxide scale forms on their surface due to high temperature corrosion phenomena. Since the ratio between the surface area and volume is much higher than for planar samples, formation of the oxide can lead to a breakaway oxidation after relatively short times. Therefore corrosion properties of...
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ESTIMATION OF YOUNG`S MODULUS OF THE POROUS TITANIUM ALLOY WITH THE USE OF FEM PACKAGE
PublikacjaPorous structures made of metal or biopolymers with a structure similar in shape and mechanical properties to human bone can easily be produced by stereolithographic techniques, e.g. selective laser melting (SLM). Numerical methods, like Finite Element Method (FEM) have great potential in testing new scaffold designs, according to their mechanical properties before manufacturing, i.e. strength or stiffness. An example of such designs...
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Heavy Metals in a High Arctic Fiord and Their Introduction with the Wastewater: A Case Study of Adventfjorden-Longyearbyen System, Svalbard
PublikacjaLongyearbyen is the largest settlement on Svalbard archipelago, with 2400 permanent residents and approximately 150,000 tourists visiting every year. The city annually releases approximately 285,000 m3 of untreated wastewater to the nearby Adventfjorden. To date, the environmental impact of this continuous input has been studied mainly regarding the sediments and benthic fauna in the fiord. Here, we present results from a study...
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Porous structures in aspects of transpirating cooling of oxycombustion chamber walls
PublikacjaA wet oxycombustion chamber, which must be effectively cooled due to high temperature evolved during the oxy-combustion process, by using the phenomena of Reynolds thermal transpiration and Navier slip velocity. Closures needed to execute mass flow rate in a microchannel, which should be treated as a single porous structure in the walls of the combustion chamber, have been obtained by applying a local 3D approach. The Navier-Stokes...
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An investigation on wetting of porous materials
PublikacjaPośrednie metody oceny zdolności zwilŜania drobnych cząstek lub materiałów porowatych wymagają wyboru cieczy odniesienia, dla której kąt zwilŜania jest równy zeru. W badaniach własnych zastosowanometodę wzniesienia kapilarnego oraz metodę flotacji filmowej dla układów mikrokulki szklane-woda i mikrokulki szklane-dekan. Uzyskane dane dla cieczy odniesienia i dla cieczy badanej wprowadzano dozmodyfikowanego równania Washburn'a i...
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Preparation of porous TiO2 films by means of pulsed laser deposition for photocatalytic applications
PublikacjaIn this work the preparation and structure properties of porous thin films of TiO2 were investigated. The films were produced by means of the pulsed laser deposition technique using laser pulses at 266nm (10Hz) and at fluencies of 1-3.5J/cm2. The process was performed in vacuum using O2 buffer gas and films were deposited on the SiO2 glass or Si substrate. X-ray diffraction (XRD) and Raman analysis of the structure and chemical...
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Heat Transfer During Pool Boiling of Water, Methanol and R141b on Porous Coated Horizontal Tube Bundles
PublikacjaThis paper presents the results of experimental investigation of water, methanol and R141b refrigerant boiling on horizontal porous coated tube bundles supposed to represent a flooded-type evaporator. Experiments were carried out for a bundle of 19 tubes in triangular layout for two pitch-to-diameter ratio values – 1.7 and 2.0 – in atmospheric and sub-atmospheric pressure conditions. Average heat transfer coefficients – both local,...
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Porous Phantoms Mimicking Tissues—Investigation of Optical Parameters Stability Over Time
PublikacjaOptical phantoms are used to validate optical measurement methods. The stability of their optical parameters over time allows them to be used and stored over long-term periods, while maintaining their optical parameters. The aim of the presented research was to investigate the stability of fabricated porous phantoms, which can be used as a lung phantom in optical system. Measurements were performed in multiple series with an interval...
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Preparation and characterization of porous scaffolds from chitosan-collagen-gelatin composite
PublikacjaNovel porous scaffolds composed of chitosan, collagen and gelatin were prepared and characterized. For preparing scaffolds gelatin and collagen isolated from fish skins with various physicochemical properties were used. In order to reduce preparation solubility glutaraldehyde in the amount of 1%, w/w relative to the total biopolymers weight in solution was used. All obtained biomaterials showed a homogeneous porosity. Protein polymer...
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A first-principles study of electronic and magnetic properties of 4d transition metals doped in Wurtzite GaN for spintronics applications
PublikacjaWe studied the electronic and magnetic properties of wurtzite GaN (w-GaN) doped with different concentrations of the 4d transition metal ions Nb, Mo, and Ru. We incorporated spin-polarized plane-wave density functional theory within an ultrasoft pseudopotential formalism. The 4d transition metals were doped at different geometrical sites to determine the geometry with the lowest total energy and the one that induced the largest...
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Influence of heterogeneous air entry pressure on large scale unsaturated flow in porous media
PublikacjaThe paper presents numerical simulations of water infiltration in unsaturated porous media containing coarse-textured inclusions embed- ded in fine-textured background material. The calculations are performed using the two-phase model for water and air flow and a simplified model known as the Richards equation. It is shown that the Richards equation cannot correctly describe flow in the presence of heterogeneities. How- ever, its...
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EFFECT OF WORKING FLUID SELECTION ON THERMAL PERFORMANCE OF HEAT EXCHANGER FILLED BY THE POROUS MATERIAL
PublikacjaThermal management of electronics semiconductor technologies that are located i.e. in a novel marine power plants or computer server rooms become very important issue for designers of such systems. Motivation and need for research in development of novel cooling strategies for modern electronics is of paramount importance. Heat exchangers filled by the porous material are a novel research topic in current heat pipe science. The...
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SYNTHETIZED MEMBRANES FOR ULTRASOUND-ASSISTED SOLVENT EXTRACTION OF POROUS MEMBRANE PACKED SOLID SAMPLES.
PublikacjaMembranes are becoming more and more popular in analytical chemistry, which is why they are used, among others, in extraction processes. Therefore, this work focuses on the process of synthesis PVDF membranes and its optimization. The obtained membranes were used as bags for the phthalate extraction in disposable diapers for babies. Extraction was accomplished by method ultrasound-assisted solvent extraction of porous PVDF membrane...
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Toxic Metals, Non-Metals and Metalloids in Bottom Sediments as a Geoecological Indicator of a Water Body’s Suitability for Recreational Use
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Experimental and Numerical Analysis of Air Trapping in a Porous Medium with Coarse Textured Inclusions
PublikacjaThe paper presents a 2D upward infiltration experiment performed on a model porous medium consisting of fine sand background with two inclusions made of coarser sands. The purpose of the experiment was to investigate the effects of structural air trapping, which occurs during infiltration as a result of heterogeneous material structure. The experiment shows that a significant amount of air becomes trapped in each of the inclusions. Numerical...
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High-temperature Corrosion of ~ 30 Pct Porous FeCr Stainless Steels in Air: Long-Term Evaluation Up to Breakaway
PublikacjaIn this work, a long-term (up to 6000 hours) corrosion evaluation of three porous (~ 30 pct of initial porosity) ferritic iron-chromium alloys with different Cr contents (20, 22, and 27 wt pct of Cr) was carried out at 600 C, 700 C, 800 C, and 900 C in air. Mass gain measurements and SEM analyses revealed that at temperatures above 600 C, all alloys exhibit breakaway corrosion, whereas at 600 C, none of the alloys were heavily...
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High temperature corrosion evaluation and lifetime prediction of porous Fe22Cr stainless steel in air in temperature range 700–900 °C
PublikacjaThis work describes a high temperature corrosion kinetics study of ~30% porous Fe22Cr alloys. The surface area of the alloy (~0.02 m2 g-1) has been determined by tomographic microscopy. The weight gain of the alloys was studied by isothermal thermogravimetry in the air for 100 hours at 700 - 900 °C. Breakaway oxidation was observed after oxidation at 850 °C (~100 hours) and 900 °C (~30 hours). The lifetime prediction shows the...
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Rozmieszczenie wybranych metali ciężkich w ekosystemie oczyszczalni hydrofitowej w Bielkowie.Distribution of heavy metals in ecosystem of free water surface system in Bielkowo.
PublikacjaIn the article the results of investigations of biomass crop and heavy metal contents in bottom sediments and in three species of plants (Glyceria maxima, Typha latifolia)inhabiting a wetland system in Bielkowo, Poland are presented. The measurements were carried out three times during the vegetation season (May, July and October). The contents of metals in different fragments of plants (leaves, stalks and roots) was analyzed....
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Hydrochars as a bio-based adsorbent for heavy metals removal: A review of production processes, adsorption mechanisms, kinetic models, regeneration and reusability of hydrochar
PublikacjaThe spread of heavy metals throughout the ecosystem has extremely endangered human health, animals, plants, and natural resources. Hydrochar has emerged as a promising adsorbent for removing heavy metals from water and wastewater. Hydrochar, obtained from hydrothermal carbonization of biomass, owns unique physical and chemical properties that are highly potent in capturing heavy metals via surface complexation, electrostatic interactions,...
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Production and Properties of the Porous Layer Obtained by the Electrochemical Method on the Surface of Austenitic Steel
Publikacja: The growing demand for implants has seen increasing interest in the introduction of new technologies and surface modification methods of metal biomaterials. This research aimed to produce and characterize a porous layer grown on austenitic stainless steel 316L, obtained via the anodization process near the micro-arc oxidation, i.e., low voltage micro-arc oxidation (LVMAO). The discussed layer significantly influences the properties...
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Local Dye Concentration and Spectroscopic Properties of Monomer−Aggregate Systems in Hybrid Porous Nanolayers
PublikacjaAnalysis of absorption, fluorescence, and time-resolved emission spectra of rhodamine 6G in hybrid porous nanolayers at high dye concentration allowed identification of two fluorescent species: monomers and fluorescent aggregates. The method of determination of mean local concentration of aggregates in matrices is proposed based on the energy transfer process between monomers and fluorescent aggregates. Evaluation of aggregate...
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Speciation of heavy metals in bottom sediments of drinking water reservoir for Gdansk, Poland – changes over the 14 years
PublikacjaThere was conducted a comparative study of the concentrations of heavy metals (Zn, Cu, Pb, and Cd) in the surface layer of sediments collected in two investigation periods: 1999–2000 and 2013. Theresults demonstrated that the degree of metals pollution decreased over time. The contamina-tion factors (Cf) calculated for Zn, Cu, Pb, and Cd were respectively 3.63, 3.86, 3.23, and 3.25 in the first period of research and 1.35, 3.42,...
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Stainless Steels Sintered Form the Mixture of Prealloyed Stainless Steel and Alloying Element Powders
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The Effects of Hydroxyapatite Addition on the Properties of the Mechanically Alloyed and Sintered Mg-RE-Zr Alloy
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Impact of the addition of dolomite to cream‐firing clays on the technological and color properties of sintered ceramics
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Pore size distribution of PC-X (porous carbon materials obtained at various temperatures)
Dane BadawczeThese data contain pore size distribution of PC-700 (porous carbon materials obtained at 700°C), PC-800 (porous carbon materials obtained at 800°C) and PC-900 (porous carbon materials obtained at 900°C) analyzed by the nitrogen adsorption/desorption technique.
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An inclination in Thermal Energy Using Nanoparticles with Casson Liquid Past an Expanding Porous Surface
PublikacjaPhysical aspects of inclined MHD nanofluid towards a stretching sheet embedded in a porous medium are visualized. Two types of nanoparticles are used named as copper and alumna dioxide with water as base fluid. Similarity transformations are used to convert the partial differential equations into the set of ordinary differential equation. Closed solutions are found to examine the velocity and the temperature profiles. It is examined...
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Synthesis and properties of porous Sr 0.96 Y 0.04 Ti 1−x Nb x O 3
PublikacjaA series of porous, single phase Sr0.96Y0.04Ti1-xNbxO3 samples was obtained using a wet synthesis method (modified citrate sol-gel) method. Temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) measurements have shown high stability of the obtained material in variable (oxidizing/reducing) atmospheres. All samples exhibit high conductivity in hydrogen atmosphere with the highest value (around 1S/cm)...
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Freshwater Ulva (Chlorophyta) as a bioaccumulator of selected heavy metals (Cd, Ni and Pb) and alkaline earth metals (Ca and Mg)
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Speciation of heavy metals in bottom sediments of a drinking water reservoir for Gdańsk, Poland – changes over the 14 years
PublikacjaThere was conducted a comparative study of the concentrations of heavy metals (Zn, Cu, Pb, andCd) in the surface layer of sediments collected in two investigation periods: 1999–2000 and 2013.The results demonstrated that the degree of metals pollution decreased over time. The contaminationfactors (Cf) calculated for Zn, Cu, Pb, and Cd were respectively 3.63, 3.86, 3.23, and 3.25 in thefirst period of...
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COMMENTS ON EXISTING ANALYTICAL SOLUTIONS TO THE WAVE-INDUCED CYCLIC RESPONSE OF A POROUS SEABED OF INFINITE THICKNESS
PublikacjaThis paper deals with the wave-induced cyclic response of a porous seabed (by means of oscillating parameters: pore-fluid pressure, soil displacement components, effective normal stress and shear stress components) due to a surface sinusoidal water-wave propagating over a seabed of infinite thickness. The main existing analytical solutions to the governing problem are critically discussed, pointing out their meaningful errors and...
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Assessment of Trace Metals Leaching During Rainfall Events from Building Rooftops with Different Types of Coverage – Case Study
PublikacjaRunoff water is an important medium transporting various types of pollution originating from the atmosphere and washed out from roofing materials. The study presents a quality assessment of runoff from different roofs in the context of trace metal concentrations. The analysed rooftops were covered with copper, tar paper and ceramic tile. The quality of the rain water collected at the same time satisfies the demands of the first...
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Combined effect of nitrogen-doped functional groups and porosity of porous carbons on electrochemical performance of supercapacitors
PublikacjaIn this work, nitrogen-doped porous carbons obtained from chitosan, gelatine, and green algae were investigated in their role as supercapacitor electrodes. The effects of three factors on electrochemical performance have been studied— of the specific surface area, functional groups, and a porous structure. Varying nitrogen contents (from 5.46 to 10.08 wt.%) and specific surface areas (from 532 to 1095 m2g−1) were obtained by modifying...
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Change in Heavy Metals Concentrations in Sediments Deposited in Retention Tanks in a Stream after a Flood
PublikacjaOur paper presents the results of heavy metal (HM) (Zn, Cu, Pb, Cd) content in bottom sediments from retention tanks along Oliwa Stream in Gdańsk, Poland, before a flood (BF) and after a flood (AF) 14-15 July 2016. The flood had a huge impact on the quality of bottom sediments and their displacement. The concentrations of HM differed significantly for research series conducted 3 months BF and 8 months AF. The concentration of Cu...
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Quantum-classical calculations of the nanomechanical properties of metals
PublikacjaTradycyjnie symulacje komputerowe układów w skali atomowej prowadzone są przy użyciu klasycznej metody dynamiki molekularnej (MD) bądź kwantowych metod ab initio. Główną wadą ujęcia klasycznego jest jego empiryczna natura, a co za tym idzie - niewielka przenośność, jego prostota natomiast pozwala na przeprowadzanie symulacji układów zawierających miliony atomów. W wyniku zastosowania metod kwantowych otrzymuje się bardziej wiarygodne...
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Impact of heavy metals on the female reproductive system
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Identification of toxic metals in human embryonic tissues
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