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Wyniki wyszukiwania dla: IMPLICIT SOLVENT
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Impact of blending with polystyrene on the microstructural and electrochemical properties of SiOC ceramic
PublikacjaIn this work, we present the electrochemical behavior and microstructural analysis of silicon oxycarbide (SiOC) ceramics influenced by an addition of polystyrene (PS). Polymer-derived ceramics were obtained by pyrolysis (1000°C, Ar atmosphere) of different polysiloxanes prepared by sol–gel synthesis. This method is very effective to obtain desired composition of final ceramic. Two alkoxysilanes phenylthriethoxysilane and diphenyldimethoxysilane...
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Thermochemistry of rare earth perovskites Na3xRE0.67−xTiO3 (RE = La, Ce)
PublikacjaHigh-temperature oxide melt solution calorimetry using sodium molybdate (3Na2O·4MoO3) solvent at 973 K was performed for the Na3xRE0.67−xTiO3 (RE = La, Ce) perovskite series. The enthalpies of formation of lanthanum perovskites from oxides (La2O3, Na2O, TiO2), are −107.25 ± 2.56, −93.83 ± 6.06, −80.68 ± 5.93, and −33.49 ± 4.26 kJ/mol and enthalpies of formation from elements are −1614.05 ± 5.37, −1596.44 ± 7.68, −1594.03 ± 7.58,...
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Efficient optimization approaches for microwave assisted extraction of high-quality antioxidant compounds from Salvia officinalis L.: UHPLC-HRMS differential analysis of phenolic profiles obtained by ultrasound and microwave extraction
PublikacjaThe study aims to optimize MAE of total phenolic compounds (TPC) and antioxidant capacity from Salvia officinalis L. leaves using a definitive screening design (DSD) and I-optimal design. UHPLC-HRMS analysis was used to identify and compare the composition of MAE and UAE optimal extracts. The results showed that DSD and I-optimal design were successfully applied for the optimization of MAE targeting phenolics and other antioxidants...
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Optimization of a Fabric Phase Sorptive Extraction protocol for the isolation of six bisphenols from juice pouches to be analysed by high performance liquid chromatography coupled with diode array detector
PublikacjaFabric Phase Sorptive Extraction (FPSE) combined with high pressure liquid chromatography using to diode array detection (HPLC-DAD) was applied for the simultaneous determination of bisphenols (BPA, BPB, BPC, BPE, BPF, BPS) in juice pouches. The FPSE procedure was optimized with regards to the critical parameters that affect the performance of the method including the selection of the FPSE membrane type and size, adsorption time,...
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Effectiveness of various types of coating materials applied in reinforced concrete exposed to freeze–thaw cycles and chlorides
PublikacjaThis study assesses the durability of coated and uncoated concrete surfaces protected with four Different coating materials: water-soluble (BW), solvent-based (BR), mineral (MI), and epoxy (EP). The durability assessment includes evaluating the absorption rate of water, pull-of adhesion strength, and coating material thickness. Concrete samples were subjected to immersion in regular water and a 7% urea solution, followed by cyclic...
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The importance of the shape of the protein-water interface of a kinesin motor domain for dynamics of the surface atoms of the protein
PublikacjaSingle kinesin motor domain immersed in water has been investigated using molecular dynamics. It has been found that local properties of water in solvation shell change along with the nature of neighboring protein surface. However, a detailed analysis leads to the conclusion that the geometrical features of hydrogen bonds and overall structure of kinesin hydration water is not very different from bulk water. The local values of...
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DMSO and TMAO—Differences in Interactions in Aqueous Solutions of the K-Peptide
PublikacjaInteractions between a solvent and their co-solute molecules in solutions of peptides are crucial for their stability and structure. The K-peptide is a synthetic fragment of a larger hen egg white lysozyme protein that is believed to be able to aggregate into amyloid structures. In this study, a complex experimental and theoretical approach is applied to study systems comprising the peptide, water, and two co-solutes: trimethylamide...
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Coordination polymers and molecular structures among complexes of mercury(II) halides with selected 1-benzoylthioureas
PublikacjaSix new 1-benzoyl-3-phenylthiourea and 1-benzoyl-3-(2-methylphenyl)thiourea complexes of mercury( II) were obtained in the reactions of the ligands with HgX2 in methanol (X = Cl, Br, I). Their structures, determined by single-crystal X-ray diffraction analysis, exhibit different stoichiometries and molecular organization. Coordination centers adopt more or less distorted tetrahedral geometry (five structures) or distorted trigonal...
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Investigating COVID-19 active pharmaceutical ingredients (APIs) degradation using Peroxydisulfate/FeMnOx binary metal oxide/Ultrasound System
PublikacjaDegradation of Favipiravir using a hybrid system of peroxydisulfate, FeMnOx binary metal oxide, and ultrasound irradiation was studied. A novel catalyst was synthesized with deep eutectic solvent (DES). The effects of DES type on catalytic performance was evaluated and the catalysts were characterized using XRD, SEM, BET, XPS, and EDS. DES-based catalysts exhibited higher efficiency due to structure change, surface area enhancement...
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Aggregation of imidazoacridinones - spectroscopic and microcalorimetric approach
PublikacjaImidazoacridinones (IA) belong to a group of polycyclic heteroaromatic antitumor compounds. IA create the aggregated form in water solution. Self-association of substances is a very important phenomenon in many fields of applied chemistry. It is also fundamental model reaction of many kinds of molecular interactions such as the micelle formation of amphiphilic substances and the binding of small organic molecules to macromolecules....
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Method for the simultaneous determination of monoaromatic and polycyclic aromatic hydrocarbons in industrial effluents using dispersive liquid-liquid microextraction with GC-MS
PublikacjaWe present a new method for simultaneous determination of 22 monoaromatic and polycyclic aromatic hydrocarbons in postoxidative effluents from the production of petroleum bitumen using dispersive liquid-liquid microextraction coupled to gas chromatography and mass spectrometry. The eight extraction parameters including the type and volume of extraction and disperser solvent, pH, salting out effect, extraction and centrifugation...
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An improved scalable method of isolating asphaltenes
PublikacjaA new, improved and scalable procedure of asphaltene fraction isolation is presented and compared to standard test methods. The new procedure uses 1:40 feedstock to solvent (n-heptane) ratio (g/mL), filtration through a cellulosic thimble and extensive washing in a Soxhlet type extractor. The group type composition and purity of the asphaltene fractions have been examined using thin-layer chromatography with flame-ionization detection....
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SURFACTANTS IN KLODNICA RIVER (KATOWICE, POLAND). PART II. QUATERNARY AMMONIUM COMPOUNDS
PublikacjaThe paper presents methods of determination of analytes of the cation group (alkyl benzyl dimethyl ammonium (BDDA-C12-C16), alkyl trimethyl ammonium (TMA), hexadecyl piridinium (HP)) in surface water and bottom sediment samples. In the sample preparation phase the solid phase extraction (SPE) or accelerated solvent extraction/ultrasound assisted extraction (ASE/UAE)-SPE technique was used and in the identification phase and quantitative...
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The importance of the shape of the protein–water interface of a kinesin motor domain for dynamics of the surface atoms of the protein
PublikacjaA single kinesin motor domain immersed in water has been investigated using molecular dynamics. It has been found that local properties of water in the solvation shell change along with the nature of the neighboring protein surface. However, a detailed analysis leads to the conclusion that the geometrical features of hydrogen bonds and overall structure of kinesin hydration water are not very different from bulk water. The local...
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Engineering Candida albicans glucosamine-6-phosphate synthase for efficient enzyme purification
PublikacjaRationally 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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Application of Passive Samplers in Monitoring of Organic Constituents of Air
PublikacjaThe principles of passive dosimetry, which has been known for over 100 years, are finding an ever increasing use in analytical practice and are being used as a convenient technique for isolation and enrichment of analytes from various environmental media. Due to its simplicity, a variety of designs, as well as the possibility of using a number of different final determination techniques, passive dosimetry has been applied in...
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Expert assessment of arguments: a method and its experimental evaluation
PublikacjaArgument structures are commonly used to develop and present cases for safety, security and other properties. Such argument structures tend to grow excessively. To deal with this problem, appropriate methods of their assessment are required. Two objectives are of particular interest: (1) systematic and explicit assessment of the compelling power of an argument, and (2) communication of the result of such an assessment to relevant...
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The equations for interactions of polarization modes in optical fibres including the kerr effect
PublikacjaWe have derived coupled nonlinear Schro¨ dinger equations (CNLSE) for arbitrary polarized light propagation in a single-mode fibre employing electromagnetic field complete description. We used a basis of transverse eigenmodes with appropriate projecting; hence, the nonlinear constants depend on the waveguide geometry. Accounting for a weak nonlinearity, which is connected to the Kerr effect, we have given explicit expressions for...
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Fast EM-driven size reduction of antenna structures by means of adjoint sensitivities and trust regions
PublikacjaIn this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using high-fidelity EM simulation. In order...
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Measuring Pulse Rate with a Webcam
PublikacjaIn this paper a simple method of measuring the pulse rate is presented. Elaborated algorithm allows for efficient pulse rate registration directly from face images captured from a webcam. The desired signal is obtained by proper channel selection and principal component analysis. To determine the accuracy of the method an ECG signal is collected together with a video recordings. The effectiveness of the algorithm is considered...
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Can we rely on the pulse transit time - pressure relationship - models comparison
PublikacjaAn unobtrusive, noninvasive and continuous pressure measurement is invaluable however, still being under research and development. There are many attempts proposing an appropriate relationship between pulse pressure velocity and pressure. Fifteen different formulas, both theoretical and experimental, describing relation between blood pressure and crosssectional area of the vessel were examined. Using these formulas the relation...
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Polyethylene glycol-coated solid-phase microextraction fibres for the extraction of polar analytes-A review
PublikacjaThe article discusses the merits and limitations of commercially available solid-phase microextraction (SPME) fibres and compares them with the new type of extraction coatings, in particular those containing polyethylene glycol as sorbent, as well as the methods of the preparation of the latter. It also analyses their possible application for the extraction of a broad spectrum of analytes, with particular emphasis on the sampling...
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Reduced order models in computational electromagnetics (in memory of Ruediger Vahldieck)
PublikacjaThis paper reviews research of Ruediger Vahldieck's group and the group at the Gdansk University of Technology in the area of model order reduction techniques for accelerating full-wave simulations. The applications of reduced order models to filter design as well as of local and nested(multilevel) macromodels for solving 3D wave equations and wave-guiding problems using finite difference and finite element methods are discussed.
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Analytical procedures for determination of cocaine and its metabolites in biological samples
PublikacjaThe dangerous effects and increased usage of illicit drugs have inspired the development of analytical methodologies. We based our review of analytical procedures for determination of cocaine (COC) and its metabolites on literature from the past two decades. Our main aim was to compare the capabilities of different analytical techniques. The diversity of matrices from which COC is determined (e.g., blood, hair, saliva, plasma,...
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Polyurethane-based aerogels: Preparation, properties, and applications
PublikacjaPolyurethane aerogels (PUAs) are interesting materials because of their high porosity, low density, and low thermal conductivity, which result in their application as thermal insulations. PUAs are mainly synthesized using di- and polyisocyanates, diols or polyols, catalysts (tertiary amines and organometallic), and solvents (which are used as reaction medium, purifying of obtained semiproducts). Preparation procedure involves several...
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Interplay of hydrogen bonding and aryl-perfluoroaryl interactions in construction of supramolecular aggregates
PublikacjaThe stacking between aryl and perfluoroaryl units is an important class of the aromatic – aromatic interactions that has attracted rapidly growing interest in recent years. Continuing interest of our group in this subject it had been prepared three new complexes of pentafluorobenzoic acid with benzyl alcohol, 4-methylbenzyl alcohol and 4-tert-butylbenzyl alcohol and in the next step investigated their self-assembly modes by...
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Main complications connected with detection, identification and determination of trace organic constituents in complex matrix samples
PublikacjaIt is well known that some problems with the determination of organic analytes at trace level can occur. This issue is connected with contamination during each stage of the analytical procedure from sampling to sample preparation up to chromatographic analysis, which often leads to false-positive or overestimated results. Another problem associated with determination of analytes occurs at trace- and ultra-trace level is a background...
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Developments in Green Chromatography
PublikacjaGreen analytical chemistry is a widely recognized concept that has led to the development of new analytical methods with reduced environmental impact and minimized analyst occupational exposure. Achievements include the development of microextraction, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) techniques. Research towards greener separation processes focuses on the elimination of toxic solvents...
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Determination of impurities in pharmaceutical products using LC-MS
PublikacjaPharmaceutical products can be contaminated by residues of solvents, reagents (used for the synthesis) or degradation products. Impurities in drug may pose a risk to human health and life, therefore analysis and identification of impurities in pharmaceutical products is veryimportant and inevitable.High performance liquid chromatography coupled with mass spectrometry (MS) is very useful technique for identification impurities in...
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Andrzej Chybicki dr inż.
OsobyZ wykształcenia informatyk, absolwent Wydziału Elektroniki, Telekomunikacji i Informatyki Politechniki Gdańskiej, doktor nauk technicznych w dziedzinie informatyka specjalizujący się w przetwarzaniau danych przestrzennych w rozproszonych systemach informatycznych. Ukierunkowany na wykorzystywanie osiągnięć i wiedzy zakresu prowadzonych badań w przemyśle. Współpracował z szeregiem podmiotów przemysłu informatycznego, geodezyjnego...
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Markov Model of Disease Development and Recovery
PublikacjaMarkov models are commonly used to simulate diseases and allow modeling of multiple health states and outcomes. Starting with the well known Le Bras multistate model (cascading failure model) with time-independent transitions we will see how simple Markov mortality models may be pressed into the service of survival and event history analysis. We will focus on more complex models which will be able to take into account remission,...
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Modeling and analysis of the effectiveness of the guard systemswith dynamic graphs
PublikacjaIn the following paper it will be presented a new model for analysis (in polynomial time) of the effectiveness of the guard systems. Therewill be presented its practical applications in problems such as searching for the weakest points of the system, planning guards' paths or cameras deployment, switching image from multiple cameras on several monitors, or interception of the intruder. This model is based on describing the guarded...
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On the convergence of a nonlinear finite-difference discretization of the generalized Burgers–Fisher equation
PublikacjaIn this note, we establish analytically the convergence of a nonlinear finite-difference discretization of the generalized Burgers-Fisher equation. The existence and uniqueness of positive, bounded and monotone solutions for this scheme was recently established in [J. Diff. Eq. Appl. 19, 1907{1920 (2014)]. In the present work, we prove additionally that the method is convergent of order one in time, and of order two in space. Some...
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HYDROSTATIC THRUST BEARING WITH REDUCED POWER LOSSES
PublikacjaIn many cases in rotating machinery, axial load is carried by tilting pad thrust bearings which have been developed since the beginning of 20th century. For high reliability and simplicity, most commonly the bearings are bath lubricated. In the times of sustainable development, however, minimization of friction losses becomes an important criterion for machinery assessment, and a strategic goal of their development. Performed calculations,...
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Support for argument structures review and assessment
PublikacjaArgument structures are commonly used to develop and present cases for safety, security and for other properties of systems. Such structures tend to grow excessively, which causes problems with their review and assessment. Two issues are of particular interest: (1) systematic and explicit assessment of the compelling power of an argument, and (2) communication of the result of such an assessment to relevant recipients. The paper...
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Simple and low-cost wireless voting system
PublikacjaThis paper presents the concept of a simple and low-cost wireless voting system working in the 868 MHz frequency band. The described system is dedicated to general shareholders assemblies but it can be easily adapted for other applications. The main advantage is its simplicity and mobility as it consists solely of three components - voting modules, a base station and a PC application from which the whole system is mamaged. This...
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Simple and low-cost wireless voting system
PublikacjaThis paper presents the concept of a simple and low-cost wireless voting system working on the 868 MHz frequency band. Described system is dedicated to general shareholders assemblies but it can be easily adapted for other applications. The main advantage is its simplicity and mobility as it consists solely of three components - voting modules, base station and a PC application from which the whole system is managed. This architecture...
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Polymeric porous membranes as solid support and protective material in microextraction processes: A review
PublikacjaPolymeric porous membranes have proven to be a versatile and efficient material for microextraction processes. In analytical practice, they are used both as a solid support and as a protective medium for improved sample preparation in various analytical applications. Polymeric porous membranes offer unique advantages in microextraction due to their large surface area and controllable pore size, eliminating interfering effects from...
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The motion influence on respiration rate estimation from low-resolution thermal sequences during attention focusing tasks
PublikacjaGlobal aging has led to a growing expectancy for creating home-based platforms for indoor monitoring of elderly people. A motivation is to provide a non-intrusive technique, which does not require special activities of a patient but allows for remote monitoring of elderly people while assisting them with their daily activities. The goal of our study was to evaluate motion performed by a person focused on a specific task and check...
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Mapping the Structural and Dynamic Determinants of pH-Sensitive Heparin Binding to Granulocyte Macrophage Colony Stimulating Factor
PublikacjaGranulocyte macrophage colony stimulating factor (GMCSF) is an immunomodulatory cytokine that is harnessed as a therapeutic. GMCSF is known to interact with other clinically important molecules, such as heparin, suggesting that endogenous and administered GMCSF has the potential to modulate orthogonal treatment outcomes. Thus, molecular level characterization of GMCSF and its interactions with biologically active compounds is critical...
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Multi-residue method for the determination of 16 recently used pesticides from various chemical groups in aqueous samples by using DI - SPME coupled with GC-MS
PublikacjaA simple and solvent-free multi-residue method has been optimized to determine 16 currently used pesticides from different chemical groups in aqueous samples. The extraction of analytes was carried out with direct immersion solid-phase microextraction (DI-SPME) and for the identification and quantitative determination gas chromatography coupled with mass spectrometry (GC-MS) was applied. Two commonly used adsorbent coatings have...
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The Role of Electrostatics in Enzymes: Do Biomolecular Force Fields Reflect Protein Electric Fields?
PublikacjaPreorganization of large, directionally oriented, electric fields inside protein active sites has been proposed as a crucial contributor to catalytic mechanism in many enzymes, and it may be efficiently investigated at the atomistic level with molecular dynamics simulations. Here, we evaluate the ability of the AMOEBA polarizable force field, as well as the additive Amber ff14SB and Charmm C36m models, to describe the electric...
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Preparation and characterisation of solution-cast Nafion membrane
PublikacjaNafion is a commercial name for a perfluorosulfonic polymer, which has been developed in 1962 by Dupont de Nemours. This polymer consists of a polytetrafluoroethylene backbone and regular spaced long perfluorovinyl ether pendant side chains terminated by a sulfonate ionic group. These sulfonate groups are responsible for cation-exchange properties of Nafion. Thanks to the ion-exchange properties, water permeability, good chemical,...
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Gelatin and gelatin/starch-based films modified with sorbitol for wound healing
PublikacjaGelatin-based films modified with sorbitol were produced from gelatin solution or gelatin/starch blends using a simple and low-cost solvent casting method, and subsequently, their physicochemical, mechanical, and biocompatibility properties were characterized. This work focused on developing and optimizing a biopolymeric blend to improve the pure biopolymers’ properties for potential biomedical applications such as wound dressing....
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Tetrahydroquinolinone derivatives exert antiproliferative effect on lung cancer cells through apoptosis induction
PublikacjaThe anticancer properties of quinolones is a topic of interest among researchers in the scientific world. Because these compounds do not cause side effects, unlike the commonly used cytostatics, they are considered a promising source of new anticancer drugs. In this work, we designed a brief synthetic pathway and obtained a series of novel 8-phenyltetrahydroquinolinone derivatives functionalized with benzyl-type moieties at position...
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Studies on formation and percolation in ionic liquids/TX-100/water microemulsions
PublikacjaTernary microemulsion systems of H2O/Triton X-100/[BMIM][Tf2N], and H2O/Triton X-100/[BMIM][PF6] were prepared, compared and characterized for phase behavior for different water/surfactant ratios, at 25 °C. It was found that a change of an anion structure in the ionic liquids determines the total monophasic area of the systems. A liquid crystalline mesophase was detected in H2O/Triton X-100/[BMIM][PF6]. The microemulsion domains...
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Synthesis of 5-Substituted 1H-Tetrazoles from Nitriles in the Presence of Heterogeneous Catalyst
PublikacjaTetrazoles are five-membered heterocyclic compounds containing in their rings four nitrogen atoms. They have wide applications as corrosion inhibitors, analytical reagents, high-energy materials and gas generating compositions. Tetrazoles also play important role in coordination chemistry as ligands and in medicinal chemistry as metabolically stable surrogates for carboxylic acids. In recent years, investigation of new method of...
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Fast Algorithms for Identification of Time-Varying Systems with Both Smooth and Discontinuous Parameter Changes
PublikacjaThe problem of noncausal identification of a time-varying linear system subject to both smooth and occasional jump-type changes is considered and solved using the preestimation technique combined with the basis function approach to modeling the variability of system parameters. The proposed estimation algorithms yield very good parameter tracking results and are computationally attractive.
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Emotions Embodied in the SVC of an Autonomous Driver System
PublikacjaA concept of embodied intelligence (EI) is considered. None of such implementations can be fully identified with artificial intelligence. Projects that dare to approach AI and EI should be based on both the AI concepts (symbolic and sub-symbolic), in solving real problems of perception and decision-making. Therefore, the EI, in this paper, is understood as a methodology that uses all available resources and algorithms from the...
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Gender approach to multi-objective optimization of detection systems by pre-selection of criteria
PublikacjaA novel idea of performing evolutionary computations for solving highly-dimensional multi-objective optimization (MOO) problems is proposed. The information about individual genders is applied. This information is drawn out of the fitness of individuals and applied during the parental crossover in the evolutionary multi-objective optimization (EMO) processes. The paper introduces the principles of the genetic-gender approach (GGA)...