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Search results for: COPULAS, HECKMAN’S SAMPLE SELECTION, ILLEGAL WORK, NON-RANDOM SAMPLE
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Direct Analysis of Samples of Various Origin and Composition Using Specific Types of Mass Spectrometry
PublicationOne of the major sources of error that occur during chemical analysis utilizing the more conventional and established analytical techniques is the possibility of losing part of the analytes during the sample preparation stage. Unfortunately, this sample preparation stage is required to improve analytical sensitivity and precision. Direct techniques have helped to shorten or even bypass the sample preparation stage; and in this...
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Mathematical approach to design 3D scaffolds for the 3D printable bone implant
PublicationThis work demonstrates that an artificial scaffold structure can be designed to exhibit mechanical properties close to the ones of real bone tissue, thus highly reducing the stress-shielding phenomenon. In this study the scan of lumbar vertebra fragment was reproduced to create a numerical 3D model (this model was called the reference bone sample). New nine 3D scaffold samples were designed and their numerical models were created....
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Application of Electrochemical Impedance Spectroscopy to evaluate cathodically protected coated steel in seawater
PublicationTwo types of organic coated carbon steel (S235JR2 grade) electrodes were exposed to artificial seawater environment. One prepared type was defect free while the other one had an intentionally introduced φ0,5 cm coating defect. Both kinds of samples were polarized during the exposure to four potentials corresponding to four different cathodic protection levels. Evolution of their EIS spectra is presented in this paper. Results obtained...
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FPGA realization of an improved alpha max plus beta min algorithm
PublicationThe generalized improved version of the alpha max plus beta min square-rooting algorithm and its realization in the Field Programmable Gate Array (FPGA) are presented. The algorithm computes the square root to calculate the approximate magnitude of a complex sample. It is especially useful for pipelined calculations in the DSP. In case of four approximation regions it is possible to reduce the peak error form 3.95% to 0.33%. This...
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Multiple access in ad-hoc wireless LANs with noncooperative stations
PublicationA class of contention-type MAC protocols (e.g., CSMA/CA) relies on random deferment of packet transmission, and subsumes a deferment selection strategy and a scheduling policy that determines the winner of each contention cycle. This paper examines contention-type protocols in a noncooperative an ad-hoc wireless LAN setting, where a number of stations self-optimise their strategies to obtain a more-than-fair bandwidth share. Two...
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Discrete element method modelling of elastic wave propagation in a meso-scale model of concrete
PublicationThis paper deals with the accurate modelling of ultrasonic wave propagation in concrete at the mesoscopic level. This was achieved through the development of a discrete element method (DEM) model capable of simulating elastic wave signals comparable to those measured experimentally. The main objective of the work was to propose a novel methodology for constructing a meso-scale model of concrete dedicated to the analysis of elastic...
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Structural, electrical, and magnetic study of La-, Eu-, and Er- doped bismuth ferrite nanomaterials obtained by solution combustion synthesis
PublicationIn this work, the multiferroic bismuth ferrite materials Bi0.9RE0.1FeO3 doped by rare-earth (RE = La, Eu, and Er) elements were obtained by the solution combustion synthesis. Structure, electrical, and magnetic properties of prepared samples were investigated by X-ray photoelectron spectroscopy, Mössbauer spectroscopy, electrical hysteresis measurement, broadband dielectric spectroscopy, and SQUID magnetometry. All obtained nanomaterials...
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The Drop-in-Drop Encapsulation in Chitosan and Sodium Alginate as a Method of Prolonging the Quality of Linseed Oil
PublicationNowadays, the encapsulation of sensitive products by various techniques has become popular as a promising preservation method. In particular, this applies to oils with a high content of unsaturated fatty acids and a high susceptibility to deterioration. This work presents the possibility of using a chitosan and sodium alginate in the form of a hydrogel membrane to protect food ingredients such as linseed oil, which is stored in...
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Ionic liquids-based microextraction techniques
PublicationIn recent years, the development of highly efficient analytical techniques is of great importance, however, the direct analysis of complex sample matrix is still impossible in many cases. Therefore, the step of sample preparation is commonly involved in an analytical procedure. Over the years, it has been realized that the major source of inaccuracy and imprecision on general analysis results from the operations associated to sample...
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Green chromatography
PublicationAnalysis of organic compounds in samples characterized by different composition of the matrix is very important in many areas. A vast majority of organic compound determinations are performed using gas or liquid chromatographic methods. It is thus very important that these methods have negligible environmental impact. Chromatographic techniques have the potential to be greener at all steps of the analysis, from sample collection...
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An analytical hierarchy process for selection of the optimal procedure for resveratrol determination in wine samples
PublicationThe study shows the application of analytical hierarchy process (AHP) in ranking the analytical procedures, that are applied for resveratrol determination in wine samples. 19 different analytical methodologies are described by metrological, economic and environmental criteria, that are further divided into 10 subcriteria. Before AHP application, the amount of input data is decreased with cluster analysis. The first run of AHP is...
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OPTICAL STRAIN MEASUREMENT OF CONCRETE VERSUS MANUAL EXTENSOMETER MEASUREMENT BASED ON THE TEST RC DEEP BEAM IN A COMPLEX STATE OF STRESS
PublicationThe purpose of this study is to compare the strain measurement techniques of concrete in R-C element subjected to the monotonic load up to the failure. In the analysis manual extensometer methods of measurements and the optical system ARAMIS for non-contact three-dimensional measurements of deformation was used. The test sample was a cantilever deep beam loaded throughout the depth which was a part of the reinforced concrete deep...
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Oil refinery dusts: morphological and size analysis by TEM
PublicationThe objectives of this work were to develop a means of sampling atmospheric dusts on the premises of an oil refinery for electron microscopic study to carry out preliminary morphological analyses and to compare these dusts with those collected at sites beyond the refinery limits. Carbon and collodion membranes were used as asupport for collection of dust particles straight on transmission electron microscopy (TEM) grids. Micrographs...
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Direct chromatographic methods in the context of green analytical chemistry
PublicationWe review analytical protocols based on gas and liquid chromatography (GC and LC), but involving no sample preparation.Green analytical chemistry seeks to minimize negative impacts of analytical chemistry. Direct analytical methods ideally fulfillthis requirement, as they preclude sample preparation - the most polluting step of the analytical procedure.We describe examples of GC methodologies for environmental and food analysis...
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Isoprostanes-Biomarkers of Lipid Peroxidation: Their Utility in Evaluating Oxidative Stress and Analysis
PublicationIsoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative...
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Raman Spectra Measurements for Chemical Identifications - Aspect of Uncertainty Sources and Reduction of Their Effects
PublicationRaman spectrometers enable fast and non-contact identification of examined chemicals. These devices measure Raman spectra and compare with the spectra database to identify unknown and often illicit chemicals (e.g. drugs, explosives) usually without any sample preparation. Raman spectra measurements are a challenge due to noise and interferences present outside the laboratories (field applications). The design of a portable Raman...
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Determination of aminoglycoside antibiotics: current status and future trends
PublicationThe use of aminoglycoside antibiotics is prevalent in medicine and agriculture. Their overuse increases their mobility in the environment, resulting in a need for reliable methods for their determination in a variety of matrices. However, the properties of aminoglycosides, in particular their high polarity, make the development of such methods a non-trivial task, inciting researchers to tackle this complex issue from different...
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Determination of fuel combustion product in airport runoff water samples using liquid–liquid extraction with gas chromatography–spectrometry
PublicationDetermination of xenobiotics in samples of airport runoff water is both a complex and indispensable task due to an increasing threat resulting from the activities of numerous airports. The aim of this study was to develop, optimize, and validate a procedure based on liquid–liquid extraction (LLE) coupled with gas chromatography–mass spectrometry (GC–MS) for the determination of polycyclic aromatic hydrocarbons (PAHs). So far, no...
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Drill holes decrease cancellous bone strength: A comparative study of 33 paired osteoporotic human and 9 paired artificial bone samples
PublicationThis study was designed to compare compressive strength of cancellous bone retrieved from the femoral head in a specimen with and without guide wire hole, with comparison to synthetic bone samples. Femoral heads retrieved from 33 patients who sustained femoral neck fractures and underwent hip arthroplasty were cut into cuboids leaving two matching samples from the same femoral head. Similar samples were prepared from synthetic femurs....
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Badanie wierności brzmienia dźwięku instrumentów wirtualnych VST/TRTAS
PublicationTematem referatu jest subiektywne badanie wierności brzmienia instrumentów wirtualnych (VST/TRTAS) wykorzystujących próbkowanie dźwięków rzeczywistych instrumentów muzycznych. Na potrzeby przedstawionej pracy wybrano kilka utworów muzyki orkiestrowej z epoki romantyzmu i klasycyzmu, nagranych przy użyciu instrumentów akustycznych. Następnie zaaranżowano fragmenty tych utworów, wykorzystując do tego instrumenty wirtualne i efekty...
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Separation of the effects of notch and macro residual stress on the MFL signal characteristics
PublicationMagnetic flux leakage (MFL) distribution for three configurations of samples has been investigated in order to study the influence of notch and plastic deformation separately as well as together. Samples have been made of S355 steel. The MFL signal measurements were carried out along the longest dimension of the sample over a length of 120 mm. Two components of magnetic field were measured: 1) tangential to the main axis and 2)...
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Principles and Developments of Solid-Phase Microextraction
PublicationSample preparation has been commonly considered a critical step of the analytical process. In this sense, remarkable efforts have been made to develop efficient sample preparation techniques which could overcome the limitations of conventional approaches. Since its inception in the early 1990’s, solid-phase microextraction (SPME) has become a widespread miniaturized sample preparation technique for extraction and preconcentration...
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GROUP COMPOSER - System for Modeling Agents’ Team Building for Tasks
PublicationMulti-agent systems consist of many autonomous units, called agents, that can interact when trying to achieve their goals. The selection of interaction partners is called team formation. Three basic approaches can be considered to match multi-agent system resources to the problem at hand. To research the properties of different approaches, a software for modeling team formation in multi-agent systems has been created and is presented...
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Computer experiments with a parallel clonal selection algorithm for the graph coloring problem
PublicationArtificial immune systems (AIS) are algorithms that are based on the structure and mechanisms of the vertebrate immune system. Clonal selection is a process that allows lymphocytes to launch a quick response to known pathogens and to adapt to new, previously unencountered ones. This paper presents a parallel island model algorithm based on the clonal selection principles for solving the Graph Coloring Problem. The performance of...
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imPlatelet classifier: image‐converted RNA biomarker profiles enable blood‐based cancer diagnostics
PublicationLiquid biopsies offer a minimally invasive sample collection, outperforming traditional biopsies employed for cancer evaluation. The widely used material is blood, which is the source of tumor-educated platelets. Here, we developed the imPlatelet classifier, which converts RNA-sequenced platelet data into images in which each pixel corresponds to the expression level of a certain gene. Biological knowledge from the Kyoto Encyclopedia...
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Multivariate analysis of impedance data obtained for coating systems of varying thickness applied on steel
PublicationElectrochemical impedance spectroscopy (EIS) has proven to be a valuable test method for the electrochemical characterization of protective coatings on metals. The common way of analysis in impedance spectroscopy is to model the impedance spectrum by means of an equivalent circuit and to extract the quantity of interest using optimization techniques. A model, corresponding to the behavior of the sample under testing, is important...
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Endocrine Disrupting Compounds – Problems and Challenges
PublicationIn this chapter, information about some of the estrogenic compounds and their environmental fate and biological influence can be found. Special attention is paid to the review of the analytical approaches used at the stages of detection and determination of Endocrine Disrupting Compounds (EDCs) in the environmental samples. Also, a brief characterization of both cellular and non-cellular bioassays is presented. The discovery of...
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Numerical analysis of vacuum drying of a porous body in the integrated domain
Publicationn the present study, the vacuum drying process of an apple slice is numerically modeled based on a control volume method. Transient two-dimensional Navier– Stokes, energy, moisture, and Luikov equations are solved by numerical coding (Fortran) to simulate the simultaneous heat and mass transfer in the ambient and apple slice, respectively. The privilege of using Luikov's model is that the capillary forces are considered, and a...
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Selected concentration techniques for gas chromatographic analysis of environmental samples
PublicationThe paper describes the role and tasks of environmental analysis and monitoring. It emphasises the leading role played by gas chromatography, especially when coupled with suitable sample preparation. This is demonstrated by some literature evidence and mainly by the author's original work on the design of sample preparation apparatus and development of GC-based methods of determination of a wide variety of organic pollutants in...
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Assessment of TFP in European and American higher education institutions – application of Malmquist indices
PublicationIn this study we apply Malmquist methodology, based on the estimation of distance measures through Data Envelopment Analysis (DEA), to a sample of 500 universities (in 10 European countries and the U.S.) over the period 2000 to 2010 in order to assess and compare their productivity. On average, a rise in TFP is registered for the whole European sample (strongest for Dutch and Italian HEIs), while the productivity of American HEIs...
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Green aspects of techniques for the determination of currently used pesticides in environmental samples
PublicationPesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in the environment is a particular danger. It is therefore crucial to monitor pesticide residues using all available analytical methods. The analysis of environmental samples for the presence of pesticides is very difficult: the processes involved in sample preparation are...
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Methodology of Selecting the Optimal Receptor to Create an Electrochemical Immunosensor for Equine Arteritis Virus Protein Detection
PublicationThe study reports a methodology of selecting the optimal receptor to create an electrochemical immunosensor for equine arteritis virus (EAV) protein detection. The detection was based on antigen recognition by antibodies immobilized on gold electrodes. Modification steps were controlled by electrochemical impedance spectroscopy and cyclic voltammetry measurements. In order to obtain the impedance immunosensor with the best parameters,...
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Metoda f-chart w zastosowaniu do projektu instalacji solarnej w budownictwie jednorodzinnym
PublicationW artykule przedstawiono algorytm obliczeń cieplnych związanych z konwersją promieniowania cieplnego oraz analizę efektów pracy instalacji solarnej przy użyciu metody korelacyjnej f-chart. Zaprezentowany algorytm obliczeń cieplnych oraz omówiona w artykule podstawowa odmiana metody f-chart zostały poparte przykładem obliczeniowym dla instalacji solarnej, która wykorzystywana jest do wspomagania układu przygotowania c.w. dla potrzeb...
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Shape-controllable synthesis of GdVO4 photocatalysts and their tunable properties in photocatalytic hydrogen generation
PublicationNovel visible light responsive materials for water splitting are essential for the efficient conversion of solar energy into hydrogen bond energy. Among other semiconductors, gadolinium orthovanadate has appropriate conduction and valence band edges positioned to split water molecules and a narrow band gap that allows the use of visible light for hydrogen generation. Thus, we present here that hydrogen evolution under visible light...
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Role of research and development in internationalization of high-tech firms: Empirical results from Poland
PublicationThe article focuses on the significance of research and development (R&D) in driving the internationalization of Polish high-tech firms. R&D is essential for businesses to remain competitive and adapt their products to the specific requirements of different markets. The study aims to investigate the relationship between R&D and the internationalization process of high-tech firms based in Poland, with a focus on the innovation context....
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Measuring radioactive powder samples on the highresolution powder diffraction beamline at the European Synchrotron Radiation Facility
PublicationThis laboratory note describes a new sample preparation technique to enable high-resolution powder diffraction experiments at the European Synchrotron Radiation Facility on radioactive samples. The sample preparation involves setting the active material in resin and several layers of encapsulation suitable for measurement at the beamline. This has allowed low-temperature measurements on very small quantities of samples, providing...
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Green aspects of techniques for the determination of pesticides in fruits and vegetables
PublicationApplied all over the world, pesticides are some of the most dangerous pollutants of the environment because of their stability, mobility, their ability to accumulate in the environment and their consequent long-term adverse effects on living organisms in general and human health in particular. Their presence in the environment is a particular danger. It is therefore crucial to monitor pesticide residues using all available analytical...
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Oznaczanie śladowych ilości związków organicznych w próbkach o złożonych matrycach zgodne z regułami ''zielonej chemii analitycznej''. Krótkołańcuchowe kwasy karboksylowe = Increasingly green approaches to the determination of selected trace organic in complex matrices. Short chain carboxylic acids
PublicationNowadays the great stress is put on environment protection and the activities to minimize the effect of chemical analyses on the environment are discussed. When environmentally friendly methodologies of analytes determination are applied the term "green analytical chemistry" is used. In general, the determination of organic compounds in complex matrices, which is a frequent analytical task, requires separation of sample components...
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THRIVING AND JOB SATISFACTION IN MULTICULTURAL ENVIRONMENTS OF MNCS
PublicationPurpose of the article The aim of the paper is to analyze the relationship between thriving and job satisfaction in multicultural environments of multinational corporations (MNCs). Methodology/methods The quantitative cross-sectional study was conducted on the sample of 128 individuals from subsidiaries of various MNCs located in Poland involved in intercultural interactions. Scientific aim The aim of this study was to examine...
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Flexible Knowledge–Vision–Integration Platform for Personal Protective Equipment Detection and Classification Using Hierarchical Convolutional Neural Networks and Active Leaning
PublicationThis work is part of an effort to develop of a Knowledge-Vision Integration Platform for Hazard Control (KVIP-HC) in industrial workplaces, adaptable to a wide range of industrial environments. The paper focuses on hazards resulted from the non-use of personal protective equipment (PPE). The objective is to test the capability of the platform to adapt to different industrial environments by simulating the process of randomly selecting...
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Sensitive simultaneous determination of 19 fluorobenzoic acids in saline waters by solid-phase extraction and liquid chromatography–tandem mass spectrometry
PublicationA solid-phase extraction (SPE) procedure using C18 stationary phase was optimized for the preconcentration of 19 fluorinated derivatives of benzoic acid (FBA): mono-, di-, tri-, and tetrafluorosubstituted in the ring, trifluoromethylbenzoic acid and 3,5-bistrifluoromethyl benzoic acid from undiluted salt-rich (>20%) reservoir waters. Quantitative (>90%) retention/elution of 16 out of 19 analyte compounds was achieved allowing a...
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Nanoparticle Tracking Analysis of Urinary Extracellular Vesicle Proteins as a New Challenge in Laboratory Medicine
PublicationUrinary extracellular vesicle (uEV) proteins may be used as specific markers of kidney damage in various pathophysiological conditions. The nanoparticle-tracking analysis (NTA) appears to be the most useful method for the analysis of uEVs due to its ability to analyze particles below 300 nm. The NTA method has been used to measure the size and concentration of uEVs and also allows for a deeper analysis of uEVs based on their protein...
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Methodology of Selecting the Optimal Receptor to Create an Electrochemical Immunosensor for Equine Arteritis Virus Protein Detection
PublicationThe study reports a methodology of selecting the optimal receptor to create an electrochemical immunosensor for equine arteritis virus (EAV) protein detection. The detection was based on antigen recognition by antibodies immobilized on gold electrodes. Modification steps were controlled by electrochemical impedance spectroscopy and cyclic voltammetry measurements. In order to obtain the impedance immunosensor with the best parameters,...
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Mechanical Properties of Human Stomach Tissue
PublicationThe dataset entitled Determination of mechanical properties of human stomach tissues subjected to uniaxial stretching contains: the length of the sample as a function of the corresponding load (tensile force) and the initial values of the average width and average thickness of the sample. All tests were conducted in a self-developed tensile test machine: PG TissueTester. The dataset allows the coefficients of various models of...
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Sampling Procedures in Studies of Cloud Water Composition: A Review
PublicationThe authors set out and classify the principles of operation of known types of cloud water collectors, and critically review their advantages and drawbacks. Analysis of the literature has yielded information on the parameters of various type of collectors—sampling time, the type of cloud from which the water sample was taken, droplet diameter collected with 50% efficiency (cut off), sample analytes/ parameters determined, types...
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Hyperelastic Microcantilever AFM: Efficient Detection Mechanism Based on Principal Parametric Resonance
PublicationThe impetus of writing this paper is to propose an efficient detection mechanism to scan the surface profile of a micro-sample using cantilever-based atomic force microscopy (AFM), operating in non-contact mode. In order to implement this scheme, the principal parametric resonance characteristics of the resonator are employed, benefiting from the bifurcation-based sensing mechanism. It is assumed that the microcantilever is made...
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Remote communication in Scrum teams - a COVID-19 preventive measure or work time optimisation?
PublicationThe article presents the impact of remote work, resulting from the COVID-19 pandemic, on the functioning of Scrum teams. Attempts have been made to analyse the positive and negative aspects of remote work. The article also looks at the impact of remote work on the level of communication and efficiency of Scrum teams. For this purpose, the author conducted research on a sample of 40 organisations that declared to use Scrum methodology,...
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Microextraction by packed sorbent: Uncommon detection techniques, sorbents, samples and analytes
PublicationAmong sample preparation approaches, the most desirable are procedures that ensure high efficiency and reproducibility, that are cheap, fast and simple, that minimize the number of operational steps and that require a small amount of sample and solvent and are thus environmentally friendly. Microextraction by packed sorbent (MEPS) is a miniaturized form of solid-phase extraction, the use of which has been continuously expanding...
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Analysis of arsenic species in environmental samples
PublicationMany analytical methods for determining arsenic in various forms in environmental samples have been developed in recent years. The main objective of this review article is the presentation and comparison of the three principal techniques for the determination arsenic compounds, namely: hydride generation (HG), voltammetry and chromatography (liquid chromatography including high-performance liquid chromatography (HPLC), and gas...
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The properties of reduced Ge-Sb-O glasses for thermoelectric devices
PublicationThe structural and electrical properties of germanium-antimonate glasses after heat treatment in hydrogen have been determined. In the case of 50GeO2-50Sb2O3 glass reduced at 340°C even for less than 1 hour a continuous layer of antimony granules is formed and its electrical properties determine the surface conductivity of the reduced sample. The bulk electrical conductivity at 100°C of this sample was determined as 1000 Scm-1...