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Search results for: strontium aluminum phosphate
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Strontium-based nanosized phosphates as anticorrosive fi llers of epoxy and polyurethane coating compositions
PublicationAnticorrosive epoxy and polyurethane coatings were compounded using zinc-free nanosized phosphates of strontium (SP) or strontium and aluminum (SAP). For comparison, a nanosized calcium aluminum ammonium phosphate (CAP) and a microsized zinc phosphate (ZP) were tested. Results of salts spray and cyclic corrosion tests revealed better anticorrosive properties of the SAP-based coatings...
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Atmospheric deposition in coniferous and deciduous tree stands in Poland
PublicationThe objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric...
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Marcin Wekwejt dr inż.
PeopleMarcin Wekwejt holds a bachelor’s degree in Biomedical Engineering (2016; J. and J. Śniadecki Bydgoszcz University of Technology & L. Rydygier Collegium Medicum), a master’s degree in Mechanical-Medical Engineering (2018; Gdańsk University of Technology & Gdańsk Medical University), and a PhD in Materials Engineering (2021; Gdańsk University of Technology). He was awarded the title of Doctor of Engineering and Technical...
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Development of iron doped strontium titanates as oxygen electrode for solid oxide fuel cells
PublicationProducing efficient solid oxide fuel cells (SOFC) without the use of harmful elements is one of the current challenges. Increasing the safety of people and reducing production costs is possible, among others, thanks to the use of iron doped strontium titanates as porous oxygen electrodes. In this thesis, the results of research on iron doped strontium titanates as potential oxygen electrodes for SOFC are presented. The research...
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Structural and Transportation Properties of Strontium Titanate Composites with Ion Conductive Oxides
PublicationThis paper has been written based on the author’s doctoral dissertation “Structural and transportation properties of strontium and titanate composites with ion conductive oxides”, prepared under the supervision of Prof. Dr. Hab. Eng. Bogusław Kusz at the Department of Solid State Physics of Gdańsk University of Technology. It reports the idea of the thesis and conclusions from the study. Niobium doped strontium titanate (Sr(Ti,Nb)O3)...
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Structure and transport properties of donor-doped barium strontium cobaltites
PublicationIn this work, Nb-substituted barium strontium cobaltites Ba0.5Sr0.5Co1-xNbxO3-δ (x = 0 – 0.4) have been fabricated and studied. The structural analysis showed that the Nb content influences the lattice constant as well as the distance between the (Co, Nb) and oxygen atoms. The study of morphology of samples showed that the Nb content does not change the porosity, grain size and morphology of the ceramics. The total electrical conductivity...
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Deposition of phosphate coatings on titanium within scaffold structure
PublicationPurpose: Existing knowledge about the appearance, thickness, and chemical composition of phosphate coatings on titanium inside porous structures is insufficient. Such knowledge is important for the design and fabrication of porous implants. Methods: Metallic scaffolds were fabricated by selective laser melting of 316L stainless steel powder. Phosphate coatings were deposited on Ti sensors placed either outside the scaffolds or...
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Mixed ionic-electronic conductivity and structural properties of strontium-borate glass containing nanocrystallites of Bi2 VO5.5
PublicationSamples of strontium borate glass containing bismuth vanadate nanocrystallites were prepared. Nanocomposites containing up to 45mol% of the Bi2VO5.5 phase exhibit electrical properties closer to the strontium-borate glass than to the ferroelectric Bi2VO5.5 ceramic. The glass matrix still may contain some part of bismuth and vanadium ions even after crystallization process and there is too little of crystalline phase to observe...
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Experimental and numerical analysis of an aluminum cantilevered beam with polymer adhesive
PublicationIn this paper, experimental and numerical investigation on a composite cantilevered aluminum beam has been conducted. The subject of the study consists of two plain aluminum elements bonded with polymer adhesive of different thickness. It has been proven in the previous study that this kind of material has high damping properties. During an experimental investigation, value of damping ratios have been obtained. The aim of a numerical...
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Phosphate and Thiophosphate Biphenyl Analogs as Steroid Sulfatase Inhibitors
PublicationIn the present work, we report convenient methods for the synthesis and biological evaluation of phosphate and thiophosphate biphenyl derivatives exhibiting steroid sulfatase (STS) activity. The described synthesis is based on straightforward preparation of biphenyl-4-ol and 40-hydroxybiphenyl- 4-carboxylic acid ethyl ester modified with various phosphate or thiophosphate moieties. The inhibitory effects of these compounds were...
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Identification of Bodner-Partom Viscoplastic Model Parameters for Some Aluminum Alloys at Elevated Temperature
PublicationThe paper presents the identification process of inelastic (viscoplastic) properties for two aluminum alloys at a temperature of 120°C. The material parameters are calculated on the basis of uniaxial tension tests. Twelve tests at elevated temperature for each alloy have been performed—three tests for four different strain rates. The main purpose of the paper is to identify the Bodner-Partom viscoplastic model parameters for two...
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Construction of glucosamine-6-phosphate synthase with an internal hexahistydyl fragment
PublicationL-Glutamine: D-fructose-6-phosphate aminotransferase (EC 2.6.1.16), known also as glucosamine-6-phosphate (GlcN-6-P) syntase, catalyzes the first committed step in the amino sugar biosynthetic pathway in prokaryotic and eukaryotic organisms. The enzyme carries out a complex reaction involving ammonia transfer and sugar phosphate isomerization. GlcN-6-P syntase is an important point of metabolic control of amino sugar biosynthesis...
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THE EFFECT OF ALTERNATIVE CUTTER PATHS ON FLATNESS DEVIATIONS IN THE FACE MILLING OF ALUMINUM PLATE PARTS
PublicationIn this paper the relationships between the alternative machining paths and flatness deviations of the aluminum plate part, were presented. The flatness tolerance of the main surface of the plate part has crucial meaning due to the assembly requirement of piezoelectric elements on the radiator. The aluminum bodies under investigation are the base part of the radiators with crimped feathers for the train industry. The surface of...
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Effect of native air-formed oxidation on the corrosion behavior of AA7075 aluminum alloys
PublicationThe microstructure of aluminum alloys plays a key role in their corrosion resistance. In particular, the presence of intermetallic precipitates differing in the potential from the alloy matrix induces local corrosion. The study presents the effect of native air-formed oxidation on the corrosion behavior of AA 7075 aluminum alloy. Various microscopic and spectroscopic techniques were used to examine the changes occurring in the...
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Investigation of corrosion behavior of 6060 and 6082 aluminum alloys under simulated acid rain conditions
PublicationInstantaneous impedance changes of 6060 and 6082 type aluminum alloys in pure water, and simulated acid rain poured into the pure water was investigated by dynamic electrochemical impedance spectroscopy (DEIS). In this way, the influence of aluminum content on the corrosion behavior of 6060 and 6082 type aluminum alloys immersed in simulated acid rain was determined. The corrosion rate of the alloy decreased with increasing Al...
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Long range molecular dynamics study of interactions of the eukaryotic glucosamine-6-phosphate synthase with fructose-6-phosphate and UDP-GlcNAc
PublicationGlucosamine-6-phosphate synthase (EC 2.6.1.16) is responsible for catalysis of the first and practically irreversible step in hexosamine metabolism. The final product of this pathway, uridine 5 diphospho Nacetyl- d-glucosamine (UDP-GlcNAc), is an essential substrate for assembly of bacterial and fungal cell walls. Moreover, the enzyme is involved in phenomenon of hexosamine induced insulin resistance in type II diabetes, which...
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PVA-Based Films with Strontium Titanate Nanoparticles Dedicated to Wound Dressing Application
PublicationBioactive materials may be applied in tissue regeneration, and an example of such materials are wound dressings, which are used to accelerate skin healing, especially after trauma. Here, we proposed a novel dressing enriched by a bioactive component. The aim of our study was to prepare and characterize poly(vinyl alcohol) films modified with strontium titanate nanoparticles. The physicochemical properties of films were studied,...
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Desensitization of glucosamine-6-phosphate synthase to inhibition by UDP-GlcNAc
PublicationGlucosamine-6-phosphate (GlcN-6-P) synthase, known also as L-Glutamine: D-fructose-6-phosphate amidotransferase, catalyzes the first committed step in the pathway leading to the ultimate formation of UDP-GlcNAc. The final product of this pathway is an activated precursor of numerous macromolecules containing amino sugars, including chitin and mannproteins in fungi, peptidoglycan and lipopolysaccharides in bacteria, and glycoproteins...
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Glucosamine-6-phosphate synthase with an oligoHis insert
PublicationGlucosamine-6-phosphate (GlcN-6-P) synthase known also as L-Glutamine: D-fructose-6-phosphate aminotransferase (EC 2.6.1.16), catalyzes the first committed step in the amino sugar biosynthetic pathway in prokaryotic and eukaryotic organisms. The final product of this pathway is an activated precursor of numerous macromolecules containing amino sugars, including chitin and mannproteins in fungi, peptydoglican and lipopolysaccharides...
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Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder
PublicationInvestigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry),...
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Aqueous solutions of NMA, Na2HPO4 , and NaH2PO4 as models for interaction studies in phosphate–protein systems
PublicationPhosphate buffers are essential for many areas of studies. However, their influence on buffered systems is often ignored. The phosphate salts can interact with biologically important macromolecules (e.g. proteins) and stabilize or destabilize them. With our research, we want to answer question what kind of interactions, if any, occur between phosphate ions and a protein backbone model — N-methylacetamide (NMA). ATR-FTIR spectroscopy...
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Electronic and ionic relaxations in strontium-borate glass and glass-ceramics containing bismuth and vanadium oxides
PublicationThe topography, microstructure and electrical properties of strontium-borate glass and SBO glass containing bismuth and vanadium oxides, were studied. The structure was measured using X-ray diffraction (XRD), Energy Dispersive X-ray Spectrometer (EDS) and Scanning electron microscope (SEM) methods. The A.C. complex conductivity was investigated as a function of temperature and frequency. The influence of the quantity of bismuth...
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Steroid Sulfatase Inhibitors Based on Phosphate and Thiophosphate Flavone Analogs
PublicationA series of phosphate and thiophosphate flavone derivatives were synthesized and biologically evaluated in vitro for inhibition of steroid sulfatase (STS) activity. The described synthesis includes the straightforward preparation of 7-hydroxy-2-phenyl-4H-chromen-4-one 3a, 2-(4-fluorophenyl)-7-hydroxy-4H-chromen-4-one 3b, 7-hydroxy-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one 3c, 7-hydroxy-2-(p-tolyl)-4H-chromen-4-one 3d modified...
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Transition Metal Oxides influence on phosphate and borate glasses structure
PublicationBorate and phosphate glasses possess many potential luminescence and optical applications. With their low melting point, they are one of the most often studied amorphous materials. In recent years these glasses, doped with transition metal oxides (TMO), gained much attention due to their tunable structural and thermal properties. Review of systems containing TMOs was presented. Additionally synthesis of binary MnO-P2O5 and MnO-B2O3...
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Modified Manganese Phosphate Conversion Coating on Low-Carbon Steel
PublicationConversion coatings are one of the primary types of galvanic coatings used to protect steel structures against corrosion. They are created through chemical reactions between the metal surface and the environment of the phosphating. This paper investigates the impact that the addition of new metal cations to the phosphating reaction environment has on the quality of the final coating. So far, standard phosphate coatings have contained...
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Bearing Capacity of aluminum bars with built-up cross section and glued or welded connections
PublicationThe paper is focused on numerical analysis and experimental test of aluminum bars with glued and welded connections between separate members. The connection properties were tested experimentally. The numerical analysis were conducted for the beam and shell model of the structure. The shape and magnitude of initial geometric imperfection was taken into account
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Heterogeneity of quaternary structure of glucosamine-6-phosphate deaminase from Giardia lamblia
PublicationThe oligoHis-tagged versions of glucosamine-6- phosphate deaminase from Giardia lamblia (GlmNagB-HisN, GlmNagB-HisC) were constructed and purified to hear homogeneity, and their kinetic and structural properties were compared to those of the wild-type enzyme (GlmNagB). Introduction of the oligoHis tag at the GlmNagB C-terminus resulted in almost complete loss of the catalytic activity, while the catalytic properties of GlmNagB-HisN...
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Assessment of FSW Welds Made of Aluminum Alloy AW7075-T651.
PublicationThis paper summarizes the results of experimental studies in which the aluminum alloy AW7075-T651 was friction stir welded (FSW) using various combinations of process parameters (rotational - R and travel speed - T). Mechanical properties of the test welds were assessed by using static tensile test and Vickers hardness measurement. The temperature of the welded plates was monitored during welding by means of thermocouples placed...
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Synthesis of phosphono and phosphate derivatives of hydroxyimino-D-alditols as new potential antifungal agents
PublicationIn search for new effective we antyfungals we focus on two enzymes involved in biosynthesis of the fungal cell wall. The first enzyme is glucosamine-6-phosphate (GlmS), which catalyzes transformation of D-fructose-6-phosphate (Fru-6P) to D-glucosamine-6-phodphate (GlcN-6P) in the chitin biosynthesis pathway. The second enzyme is phosphomannose isomerase (PMI) repored to play a crucial role in biosynthesis of many mannosylated structures,...
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Impedance Studies of Phosphate-iron Glasses Containing Niobium and Titanium
PublicationThe ac and dc conductivity in phosphate-iron-niobate glasses with addition of titanium oxide was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and confocal microscopy methods. The obtained results show that all samples are amorphous but they...
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Mobility and distribution of barium and strontium in profiles of podzolic soils
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Dosimetric features of strontium orthosilicate (Sr2SiO4) doped with Eu2+
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Separate synthesis and evaluation of glucitol bis-phosphate and mannitol bis-phosphate, as competitive inhibitors of fructose bis-phosphate aldolases
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Properties of Oxygen Vacancy and Hydrogen Interstitial Defects in Strontium Titanate: DFT + Ud,p Calculations
PublicationThis work presents extensive theoretical studies focused on the mixed ion-electron transport in cubic strontium titanate (STO). A new approach to the description of this difficult system was developed within the framework of linear-scaling Kohn–Sham density functional theory, as realized in the ONETEP program. The description we present is free of any empirical parameters and relies on the Hubbard U and Hund’s J corrections applied...
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Long-term operating conditions for different sorption materials to capture phosphate from domestic wastewater
PublicationThis paper presents the results of a study on the possibility of applying various configured filters filled with a mixture of Rockfos® and Leca® material for the effective capture of phosphate from domestic wastewater. The tests were carried out for two years at two wastewater flow rates (20 and 40 L/day) in three pairs of filtration columns with a volume of filter material equal to 20 liters each. Columns 1A and 1B were filled...
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Ultra-thin film of aluminum oxide influence on the plasmon resonance in gold nanostructures
Open Research DataUltra-thin film of aluminum oxide influence on the plasmon resonance in gold nanostructures was measured by UV-VIS spectroscopy. Ultra thin film of Al2O3 was deposited on a gold nanostructures. Thickness of film was 2nm - 8nm. Shift of plasmon resonance was observed, as a result of various dielectric constant of layer.
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Aggregation properties of some zirconium phosphate loaded with dirhenium(III) complexes
PublicationOne of the important areas of modern science is the selection of the right forms of drug delivery. Layered inorganic nanoparticles, such as zirconium phosphate, have proven themselves well in this area. The study of the properties of these systems and methods of their preparation makes it possible to determine a rational technology of their manufacture, storage conditions as well as suggest a possible mechanism of therapeutic action....
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Modification of TiO2 nanotubes by graphene–strontium and cobalt molybdate perovskite for efficient hydrogen evolution reaction in acidic medium
PublicationHerein, we demonstrate that modification of TiO2 nanotubes with graphene–strontium and cobalt molybdate perovskite can turn them into active electrocatalysts for hydrogen evolution reaction (HER). For this purpose, a simple method of hydrothermal synthesis of perovskites was developed directly on the TiO2 nanotubes substrate. Moreover, the obtained hybrids were also decorated with graphene oxide (GO) during one-step hydrothermal...
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Inhibitors of glucosamine-6-phosphate synthase as potential antimicrobials or antidiabetics – synthesis and properties
PublicationGlucosamine-6-phosphate synthase (GlcN-6-P synthase) is known as a promising target for antimicrobial agents and antidiabetics. Several compounds of natural or synthetic origin have been identified as inhibitors of this enzyme. This set comprises highly selective L-glutamine, amino sugar phosphate or transition state intermediate cis-enolamine analogues. Relatively low antimicrobial activity of these inhibitors, poorly penetrating...
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Investigation of the structural and thermal properties of aluminum-rich Ca–Al–Si–O–N glasses
PublicationIn this paper, we investigate the structure and thermal properties of aluminum-rich transparent Ca–Al–Si–O–N glasses. The obtained glasses were prepared by a traditional melt-quenching technique at 1650 °C using AlN as the nitrogen source. The obtained glasses have a nAl/nSi>1 and contain up to 17 eq.% of N. The structure of the glasses was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, infrared, and Raman...
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The use of Response Surface Methodology for reliability estimation of aluminum silo subjected to wind load
PublicationAn axisymmetric aluminum silo model with a single, standardized geometric imperfection of its lateral surface is considered. The silo is wind – loaded only. The paper is focused on the critical, or limit value of wind pressure, both producing a loss of stability of the silo. This value is affected by vertical coordinate (position) of the imperfection and the angular relation between the imperfection and the wind direction. Reliability...
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Local buckling of thin-walled channel member flange made of aluminum alloy
PublicationThe paper deals with local stability of the thin-walled compressed flange of channel columns and beams made of aluminum alloy. The aim of paper is to find critical stress of local buckling of the flange member taking into account the web-flange interaction in linear and nonlinear elastic range of the member material. The governing differential equation of the problem is derived with aid of the principle of stationary total potential...
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Engineering Candida albicans glucosamine-6-phosphate synthase for efficient enzyme purification
PublicationRationally designed muteins of Candida albicans glucosamine-6-phosphate synthase, an enzyme known as a promising target for antifungal chemotherapy, were constructed, overexpressed in Escherichia coli and purified to near homogeneity. To facilitate and to optimize the purification of the enzyme, three recombinant versionscontaining internal oligoHis fragments were constructed: (i) by substituting residues 343 - 348...
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Experimental and Numerical Study on Mechanical Characteristics of Aluminum/Glass Fiber Composite Laminates
PublicationThe fiber-metal composites made of aluminum sheets and glass fibers reinforced with a polyester resin as the matrix were studied. The composites were prepared by hand lay-up method. Some aspects of manufacturing affecting the composite behavior were considered. In particular, the influences of the arrangement of layers and their number on the mechanical and physical properties of composites with ten different compositions were...
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Aluminum-TiO2 NPs Composites as Non-precious Catalysts for Efficient Electrochemical Generation of Hydrogen
PublicationIn this paper, we demonstrated, for the first time, aluminum titania nanoparticle (Al-TiO2 NP) composites with variable amounts of TiO2 NPs as nonprecious active catalysts for the electrochemical generation of H2. These materials were synthesized by mixing desired amounts of hydrogen titanate nanotubes (TNTs), fabricated here by a cost-effective approach at moderate hydrothermal conditions, with aluminum powder (purity 99.7%; size...
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Evaluation of Temporal Leachability of Strontium from Building Materials to Environment
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Local buckling of compressed flange of cold-formed channel members made of aluminum alloy
PublicationThe paper deals with local buckling of a compressed single flange of thin-walled channel cold- formed columns and beams made of aluminum alloy. Material is described by means of the Ramberg-Osgood constitutive equation. Axial compression of the columns and beams undergoing bending is taken into consid- eration. A simple model of the member flange in the form a long beam elastically connected to the web is used to find the critical...
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Corrosion Inhibition Mechanism and Efficiency Differentiation of Dihydroxybenzene Isomers Towards Aluminum Alloy 5754 in Alkaline Media
PublicationThe selection of efficient corrosion inhibitors requires detailed knowledge regarding the interaction mechanism, which depends on the type and amount of functional groups within the inhibitor molecule. The position of functional groups between different isomers is often overlooked, but is no less important, since factors like steric hinderance may significantly affect the adsorption mechanism. In this study, we have presented how...
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Mixed conductivity in tungstenite-phosphate glasses containing alkali metal ions
PublicationThe conductivity of glasses in the 50WO3-(50-x)P2O5-xA2O (A = Na, K, Cs) system has been investigated as a function of composition. It is shown that in tungstenite-phosphate glasses containing different alkali metal ions the conductivity decreases with an increase in the alkali metal ion content. A decrease in conductivity is larger for heavier ions and reaches more than seven orders of magnitude in the case of glass containing...
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Phosphate tricyclic coumarin analogs as steroid sulfatase inhibitors: synthesis and biological activity.
PublicationIn the present work, we report convenient methods for the synthesis and biological evaluation of phosphate tricyclic coumarin derivatives as potential steroid sulfatase inhibitors. The described synthesis includes the straightforward preparation of 7-hydroxy-2,3-dihydro-1H-cyclopenta[c]chromen-4-one, 3-hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one and 3-hydroxy-8,9,10,11-tetrahydro-7H-cyclohepta[c]chromen-6-one modified...