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Search results for: EXTRACTION METHODS
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Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples
PublicationIn the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application...
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Investigation of vortex assisted magnetic deep eutectic solvent based dispersive liquid–liquid microextraction for separation and determination of vanadium from water and food matrices: Multivariate analysis
PublicationA new and simple vortex assisted magnetic deep eutectic solvent dispersive liquid–liquid microextraction procedure (VA-MDES-DLLME) was developed for the determination of vanadium (V) in food and water samples by flame atomic absorption spectrometry (FAAS). In the extraction medium, a bis(acetylpivalylmethane) ethylenediimine (H2APM2en) was used for the complexation of V(V) in sample solution at pH 6. The VA-MDES-DLLME was optimized...
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Sorbents modified by deep eutectic solvents in microextraction techniques
PublicationIn recent years, considerable attention has been directed towards the employment of green solvents, specifically deep eutectic solvents (DES), in liquid phase microextraction techniques. However, comprehensive and organized knowledge regarding the modification of sorbent surface structures with DES remains limited. Therefore, this paper reviews the application of DES in modifying and improving the properties of sorbents for microextraction...
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Thermal Imaging in Wound Healing Diagnostics
PublicationResults of a project searching for objective, quantitative evaluation of postoperative wound healing in cardiosurgery are presented. We propose simple thermal models of the healing processes after cardiosurgery interventions as objective descriptors allowing classification of patients for extraction and following recovery at home or for prolonged treatment in a hospital. Classification of healing as the normal process or as a process...
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Oxidation step in the preparation of benzocamalexin: The crystallographic evidence
PublicationThe study of oxidation step in the preparation of benzocamalexin by the α-amidoalkylation–oxidation sequence revealed the formation of perchloro-1,2-phenylene dibenzoate as the product of transformation of tetrachloro- 1,2-benzoquinone applied as the oxidant. The structures of benzocamalexin and perchloro-1,2-phenylene dibenzoate were confirmed by X-ray diffraction analysis. The extraction step in the final isolation of benzocamalexin...
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Determination of volatile organic compounds in water samples using membrane-solid phase microextraction (M-SPME) (headspace version)
PublicationThe results of a study on the use of membrane-solid phase microextraction (M-SPME) for sampling volatile organic compounds (VOCs) from the headspace above the liquid medium are presented. The sampled VOCs were subsequently quantified by gas chromatography (GC). Two systems were compared in this study, i.e. a novel two-phase sorption system (M-SPME), and a commercial fibre. Headspace sampling using SPME was optimized with respect...
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Semantic URL Analytics to Support Efficient Annotation of Large Scale Web Archives
PublicationLong-term Web archives comprise Web documents gathered over longer time periods and can easily reach hundreds of terabytes in size. Semantic annotations such as named entities can facilitate intelligent access to the Web archive data. However, the annotation of the entire archive content on this scale is often infeasible. The most efficient way to access the documents within Web archives is provided through their URLs, which are...
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Influence of Storage Time and Temperature on the Toxicity, Endocrine Potential, and Migration of Epoxy Resin Precursors in Extracts of Food Packaging Materials
PublicationThe aim of the present study was to establish a standard methodology for the extraction of epoxy resin precursors from several types of food packages (cans, multi-layered composite material, and cups) with selected simulation media (distilled water, 5% ethanol, 3% dimethyl sulfoxide, 5% acetic acid, artificial saliva) at different extraction times and temperatures (factors). Biological analyses were conducted to determine the acute...
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Determination of flavanols by liquid chromatography with fluorescence detection. Application to the characterization of cranberry-based pharmaceuticals through profiling and fingerprinting approaches
PublicationIn this work, a new method based on reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) was established for the determination of catechins and related oligomeric proanthocyanidins (PACs) in cranberry-based pharmaceuticals. Compounds were recovered by liquid extraction using methanol/water/hydrochloric acid (60:39:1, v:v:v) as the extraction solvent. The chromatographic separation was carried...
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Solid phase microextraction: state of the art, opportunities and applications
PublicationSolid phase microextraction is one of the most popular green techniques used for sample preparations in analytical chemistry. It is a simple, rapid, sensitive, and solvent-free technique. Since SPME was first introduced in the early 1990s, there has been an intensification of research in order to elaborate new methodical solutions in many research facilities around the world, which could increase the use of this technique. More...
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Magnetic hydrophobic deep eutectic solvents for orbital shaker-assisted dispersive liquid-liquid microextraction (MAGDES-OS-DLLME) - determination of nickel and copper in food and water samples by FAAS
PublicationIn this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and...
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Investigation of tetrabutylammonium bromide-glycerol-based deep eutectic solvents and their mixtures with water by spectroscopic techniques
PublicationDeep eutectic solvents (DES) are formed by an acceptor and a donor of hydrogen bonds. They are generally considered as a possible alternative to hazardous organic solvents in various fields. Very recently they have also appeared in analytical chemistry, used mainly for the separation of analytes before instrumental quantification. For the development of new extraction procedures, it is important, among other things, to understand...
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Developments in ultrasound-assisted microextraction techniques for isolation and preconcentration of organic analytes from aqueous samples
PublicationThe great potential of ultrasonic assistance in sample preparation, especially extraction, is being recognized. In this review, we discuss the applications of ultrasonic radiation in assisting microextraction. Topics covered include ultrasound-assisted emulsification microextraction, ultrasound-assisted-emulsification-dispersive liquid-liquid microextraction, and ultrasound-assisted hollow-fiber liquid-phase microextraction with...
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Generalized adaptive comb filter with improved accuracy and robustness properties
PublicationGeneralized adaptive comb lters can be used to identify/track parameters of quasi-periodically varying systems.In a special, signal case they reduce down to adaptive comblters, applied to elimination or extraction of nonstationarymulti-harmonic signals buried in noise. We proposea new algorithm which combines, in an adaptive way, resultsyielded by several, simultaneously working generalizedadaptive comb lters. Due to its highly...
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Identification of regions of interest in video for a traffic monitoring system
PublicationA system for automatic event detection in the camera image is presented in this paper. A method of limiting a region of interest to relevant parts of the image using a set of processing procedures is proposed. Image processing includes object detection with shadow removal performed in the modified YCbCr color space instead of RGB. The proposed procedures help to reduce the complexity of image processing algorithm and result in...
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Determination of chlorine concentration using single temperature modulated semiconductor gas sensor
PublicationA periodic temperature modulation using sinusoidal heater voltage was applied to a commercial SnO2 semiconductor gas sensor. Resulting resistance response of the sensor was analyzed using a feature extraction method based on Fast Fourier Transformation (FFT). The amplitudes of the higher harmonics of the FFT from the dynamic nonlinear responses of measured gas were further utilized as an input for Artificial Neural...
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Knowledge representation of motor activity of patients with Parkinson’s disease
PublicationAn approach to the knowledge representation extraction from biomedical signals analysis concerning motor activity of Parkinson disease patients is proposed in this paper. This is done utilizing accelerometers attached to their body as well as exploiting video image of their hand movements. Experiments are carried out employing artificial neural networks and support vector machine to the recognition of characteristic motor activity...
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Poly(hydroxybutyrate-co-hydroxyvalerate) as a biodegradable binder in a negative electrode material for lithium-ion batteries
PublicationIn this work, graphite-based negative electrode for lithium-ion battery consisting a novel and biodegradable binder poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is compared with standard graphite electrode with polyvinylidene fluoride (PVDF) as a binder. The rate and cycling performance of lithium ion insertion/extraction of electrodes with PHBV in a half-cell configuration are evaluated. Moreover, on the basis of the electrochemical...
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Ekstrakcja do fazy stałej niejedno ma imię
PublicationW czasach, gdy we wszystkich przejawach aktywności człowieka trzeba się odnieść do przesłanek leżących u podstaw zrównoważonego rozwoju trudno jest uzasadnić stosowanie w praktyce analitycznej takich procedur i operacji, które pociągają za sobą konieczność:użycia dużych ilości rozpuszczalników i odczynników chemicznychdużych nakładów energii czy też przyczyniają się do wzrostu ekspozycji pracowników laboratoriów na niekorzystne...
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Determination of the Major By-Products of Citrus hystrix Peel and Their Characteristics in the Context of Utilization in the Industry
PublicationKaffir lime (Citrus hystrix) is a popular citrus in Southeast Asia. Despite the growing interest in the peel of the fruit, the leaves are the most frequently used part of the fruit. The aim of the study was to determine the main by-products of the peel, such as pectins, minerals, essential oil, and bioactive compounds, and to evaluate the possibility of using them in various branches of industry. In the study of the essential oil...
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Antioxidant activities and bioactive components in some berries
PublicationThe objective of this study was to evaluate the antioxidant and binding effects of gooseberry, a less-stud-ied berry, and to compare with blueberry and cranberry in the model of interaction with human serum albumin (HSA). The relationship between the scavenging properties of dietary polyphenols of the selected berries and their affinities for HSA were investigated by fluorescence anal- ysis. In order to perform the extraction and...
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Microwave Characterization of Dielectric Sheets in a Plano-Concave Fabry-Perot Open Resonator
PublicationDespite its long history, a double-concave (DC) Fabry-Perot open resonator (FPOR) has recently gained popularity in the characterization of dielectrics in the 20–110 GHz range, mainly due to such novel accomplishments as full automation of the measurement process and the development of even ore accurate and computationally efficient electromagnetic model. However, it has been discovered that such a DC resonator suffers from unwanted...
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Ionogel sorbent coatings for determining organophosphorus and pyrethroid insecticides in water and fresh juice samples by headspace-solid phase microextraction
PublicationThe sol–gel method yielded three different ionogel sorbent coatings that were obtained based on a silica material containing ionic liquids (ILs) immobilized in its pores. Two ILs, triethylsulfonium bis(trifluoromethylsulfonyl) imide [Set3][TFSI] and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C4C1Pip][TFSI], as well as their equimolar mixture [Set3/C4C1Pip], were used to obtain ionogel fibers. The developed...
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Head-Space SPME for the Analysis of Organophosphorus Insecticides by Novel Silica IL-Based Fibers in Real Samples
PublicationThis work demonstrates the suitability of a newly developed ionic liquid (IL)-based silica SPME fiber for the determination of seven organophosphorus insecticides in cucumber and grapefruit samples by headspace solid-phase microextraction (HS-SPME) with a gas chromatography–flame ionization detector (FID). The sol-gel method released four different sorbent coatings, which were obtained based on a silica matrix containing ILs immobilized...
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Simultaneous determination of ibuprofen and its metabolites in complex equine urine matrices by GC-EI-MS in excretion study in view of doping control
PublicationA novel assay for the simultaneous determination of ibuprofen (IBU) and its four probable metabolites, 1-hydroxyibuprofen (1-OH IBU), 2-hydroxyibuprofen (2-OH IBU), 3-hydroxyibuprofen (3-OH IBU) and carboxyibuprofen (CBX IBU) in equine urine samples with the application of Gas Chromatography-Electron Ionization-Mass Spectrometry (GC-EI-MS) has been developed and elaborated. The new approach for sample preparation including minimizing...
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Residence time distribution in rapid multiphase reactors
PublicationResidence time distribution (RTD) provides information about average hydraulic residence time and the distribution of material in the reactor. A method for determining RTD for reactors with very short hydraulic residence times is deconvolution based on extraction of real RTD by the analysis of a non-ideal input signal. The mean residence time and dispersion were determined for the spinning fluids reactor (SFR). For the first time...
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Speciation of heavy metals in wastewater and rejected waters from multistage bioreactors (MUCT)
PublicationThe objective of the study is to investigate the occurrence and availability of selected heavy metals after subsequent stages of treatment in WWTP with activated sludge (enhanced biological N and P removal). To achieved the target it was necessary to recognize the allocation of selected heavy metals between aqueous and solid phase in wastewater and reject waters. Application of sequential extraction of such metals as Cd Zn, Pb,...
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Lower rim substituted p-tert-butyl-calix[4]arene. Part 17. synthesis, extractive and ionophoric properties of p-tert-butylcalix[4]arene appended with hydroxamix acid moieties
PublicationThe synthesis and characterization of four p-tert-butylcalix[4]arene-hydroxamic acidc are reported. The dependence of the metal ion binding, assessed by liquid extraction of the metal nitrates from water into dichloromethane in individual and competitive experiments, on the ligand structure, is presented. The results showed that those ligands could be successfully used in separation process of trnasition and heavy metals often...
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Face Recognition: Shape versus Texture
PublicationThis paper describes experiments related to the application of well-known techniques of the texture feature extraction (Local Binary Patterns and Gabor filtering) to the problem of automatic face verification. Results of the tests show that simple image normalization strategy based on the eye center detection and a regular grid of fiducial points outperforms the more complicated approach, employing active models that are able to...
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Application of Headspace Solid-phase Microextraction with Poly(1-vinyl-3- Hexylimidazolium Chloride) Polymeric Ionic Liquid Coating using GC - MS to Determine Volatile Fatty Acids in Dairy Wastewater
PublicationVolatile fatty acids were determined in this study using headspace solid-phase microextraction (HS-SPME) with a poly(1-vinyl-3-hexylimidazolium chloride) polymeric ionic liquid coated fiber followed by gas chromatography - mass spectrometry. Experimental parameters such as extraction time and temperature, sample volume as well as desorption time and temperature were optimized. Detection limits of the method were in the range of...
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Vocalic Segments Classification Assisted by Mouth Motion Capture
PublicationVisual features convey important information for automatic speech recognition (ASR), especially in noisy environment. The purpose of this study is to evaluate to what extent visual data (i.e. lip reading) can enhance recognition accuracy in the multi-modal approach. For that purpose motion capture markers were placed on speakers' faces to obtain lips tracking data during speaking. Different parameterizations strategies were tested...
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Challenges in preparing honey samples for chromatographic determination of contaminants and trace residues
PublicationThe determination of contaminations and residues in honey is of growing concern over past few years, especially that these compounds can not only diminish beneficial properties of honey but more importantly, if present in significant amounts, can pose serious threat to human health. Since honey is characterized by complex composition of the matrix sample, it is often necessary to apply clean-up step, in order to eliminate interfering...
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Effect of shallow traps on admittance spectra of the system carrying SCLC and on values of charge carrier mobility extracted from susceptance
PublicationThe work concerns small-signal spectra of space-charge-limited current below threshold frequency (ft) of shallow traps. It is shown that below ft the small-signal concentration of trapped charge carriers is proportional to and in phase with small-signal concentration of free charge carriers, so there is no room for “slow shallow traps”. Conductance can be reduced by the traps, however no change in the range of real capacitance...
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Determination of Pesticide Residues in Honey using the GC×GC-TOFMS Technique
PublicationIn this study, a QuEChERS method and gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) was developed for rapid extraction and simultaneous determination of 12 pesticide residues in honey. The GCxGC-TOFMS method was validated according to the SANCO guidance in terms of linearity, selectivity, reproducibility and recovery. Regarding the results, recovery rates ranged between 70-120% with relative standard...
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SILICA AEROGEL TOWARDS ANODES FOR LITHIUM-ION BATTERIES
PublicationAn increasing demand for electrochemical energy storage and conversion devices stimulates progress in research on electrode and electrolyte materials. In the field of electrodes materials, silicon is the one of the most promising anode materials for Li-ion batteries. However silicon has the drastic volume variation (around 3 times lower on extraction) during insertion and extraction of lithium ions. As an alternative, nanocomposites...
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New approach for e-cigarette aerosol collection by an original automatic aerosol generator utilizing melt-blown non-woven fabric
PublicationCurrently, there is lack of standardized conditions for the collection and analysis of e-cigarette (EC) aerosol. Considering the urgent need for the development of these guidelines, a procedure for EC aerosol analysis was developed. A novel automatic e-cigarette aerosol generator was designed. For the first time, melt-blown non-woven fabric was applied for the effective uptake of compounds released from vaporized e-liquid. The...
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Determination of high-intensity sweeteners in beverages by high-performance liquid chromatography with mass spectrometry detection.
PublicationThe objective of the present study was to measure the concentration of nine high intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin dihydrochalcon, neotame, saccharin and sucralose) in different types of beverages available on the polish market. The proposed methodology reported here consists of a extraction with buffer composed of formic acid and N,N-diisopropylethylamine (pH 4.5) followed...
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Development and Validation of SPE-HPLC-MS/MS Method for Determining Cyclophosphamide in Surface Waters
PublicationA rapid and selective method for trace amounts determination of cyclophosphamide in surface water samples has been developed. A solid phase extraction SPE method for extraction and clean-up procedure has been optimized for determination by reversed-phase high-performance liquid chromatography with tandem mass spectrometry. The analyses proceed in the positive ion mode by means of the electrospray ionization method (ESI). Clean...
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Electrical Simulations of the SIS100 Superconducting Dipole and Quadrupole Circuits: Transients, Earthing and Failure Modes
PublicationThe 100 Tm superconducting synchrotron SIS100 is the main accelerator of the international Facility for Antiproton and Ion Research (FAIR) currently under advanced construction in Darmstadt, Germany. The SIS100 dipole circuit which creates the magnetic field required to bend the beam, consists of 108 dipoles distributed over six arc sections of the ring. The magnetic field for the beam focusing is generated by three individual...
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Development of thin film SPME sorbents based on deep eutectic solvents and their application for isolation and preconcentration of endocrine-disrupting compounds leaching from diapers to urine
PublicationIn this study, the thin film solid phase microextraction (TF-SPME) based on a novel sorbent composed of deep eutectic solvent (DES) is proposed. Among several synthesized sorbents the most efficient was DES containing trihexyl(tetradecyl)phosphonium chloride and docosanol mixed with polydimethylsiloxane (PDMS) in a molar ratio 1:3:0.25 to achieve a more stable structure. The proposed sorbent was applied on a fiberglass mesh and...
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Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
PublicationEffective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat...
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Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
PublicationEffective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat supply...
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Application in circular sawing machines of the experimental results of investigations of the chip removing system operation
PublicationThe experimental results of the chip removing system operation are presented. The main aim of them was to optimize suction system of the panel saw Fx3 and its follower Fx550. The attention was focused on the upper casing, which was the part of removing system. Within the framework of the work a systematic experimental study of pressure distribution in the casing during operation of the selected rotational speed of saw blade with...
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Analytical procedures for determination of cocaine and its metabolites in biological samples
PublicationThe 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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New Algorithms for Adaptive Notch Smoothing
PublicationThe problem of extraction/elimination of a nonstationary complex sinusoidal signal buried in noise is considered. This problem is usually solved using adaptive notch filtering (ANF)algorithms. It is shown that accuracy of signal estimation can be increased if the results obtained from ANF are further processed using a cascade of appropriately designed filters. The resulting adaptive notch smoothing (ANS) algorithms can be employed...
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Initial Considerations
PublicationChemical processes have made use of a wide number of volatile organic solvents due to their efficiency in countless unit operations. The increasing knowledge on the environmental, health, and safety hazards associated to their use has significantly contributed to the search for greener alternatives. The primary purpose of this book is to provide an overview of alternative solvents with reduced issues that have successfully replaced...
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Contextual ontology for tonality assessment
Publicationclassification tasks. The discussion focuses on two important research hypotheses: (1) whether it is possible to construct such an ontology from a corpus of textual document, and (2) whether it is possible and beneficial to use inferencing from this ontology to support the process of sentiment classification. To support the first hypothesis we present a method of extraction of hierarchy of contexts from a set of textual documents...
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Dissociation of furan-2-carboxylic acid by low energy electrons
PublicationElectron attachment to molecular target can lead to a variety of negative fragment ions. We experi- mentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C3H3O2 − COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup...
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Multi-objective optimization of microextraction procedures
PublicationOptimization of extraction process requiresfinding acceptable conditions for many analytes and goodperformance in terms of process time or solvent consumption. These optimization criteria are oftencontradictory to each other, the performance of the system in given conditions is good for some criteriabut poor for others. Therefore, such problems require special assessment tools that allow to combinethese contradictory criteria into...
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Monitoring of volatile organic compounds (VOCs) in atmospheric air. Part I. On-line gas analyzers
PublicationThe paper reviews the subject literature concerning the analytical instruments routinely used for monitoring volatile organic compounds in atmospheric air. The analyzers are classified as stationary or mobile according to their ease of transport. Stationary DOAS (Differential Optical Absorption Spectroscopy) analyzer is characterized, as are MIMS (Membrane Introduction Mass Spectrometry), MESI (Membrane Extraction with Sorbent...