wyświetlamy 1000 najlepszych wyników Pomoc
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Head-Space SPME for the Analysis of Organophosphorus Insecticides by Novel Silica IL-Based Fibers in Real Samples
PublikacjaThis 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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Exploratory analysis and ranking of analytical procedures for short-chain chlorinated paraffins determination in environmental solid samples
PublikacjaShort-chain chlorinated paraffins are ones of the most recent chemical compounds that have been classified as persistent organic pollutants. They have various applications and are emitted to the environment. Despite the fact, that the content levels of these compounds in the environmental compartments should be monitored, there is still a lack of well-defined and validated analytical procedures, proposed or suggested by the national...
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Green sample preparation techniques for chromatographic determination of small organic compounds
PublikacjaAccurate monitoring of the state of the environment requires the introduction of additional isolation and/or preconcentration step prior to the chromatographic determination. In this work the information about novel methodological and instrumental solutions in relation to different variants of microextraction techniques are presented. Attention is focused on analytical procedure and suitable analytical tools for extraction of the...
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Soxhlet Extraction and New Developments Such as Soxtec in: Comprehansive Sampling and Sample Preparation
PublikacjaSoxhlet extraction is one of the most popular techniques for extraction of analytes from solid materials. Since its discovery in 1879, the standard Soxhlet technique has been routinely applied in almost every analytical laboratory. Up to this day, Soxhlet extraction technique remains a standard technique to which the performance of modern extraction techniques is compared.Over the years, an intensive research on different modifications...
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Green analytical chemistry in sample preparation for determination of trace organic pollutants
PublikacjaW pracy przedstawiono przyjazne środowisku techniki analityczne, stosowane w celu izolacji i wzbogacania analitów. Ilość używanych rozpuszczalników jest ograniczana przez stosowanie alternatwnych rozpuszczalników, technik bezrozpuszczalnikowych, ekstrakcji wspomaganych czynnikami zewnętrznymi oraz przez wprowadzanie mikrosystemów analitycznych.
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Fractional delayor application in self-tuning sub-sample delay estimator
PublikacjaW artykule przedstawiono nowe rozwiązanie samonastrajalnego estymatora opóźnienia sygnału sinusoidalnego. Estymator działa w czasie dyskretnym. Proponowane rozwiązanie wykorzystuje kaskadowe połączenie cyfrowego filtru ułamkowo opóźniającego służącego do synchronizacji próbkowania i liniowo-fazowego cyfrowego filtru Hilberta. Oryginalność polega na zastosowaniu tu filtrów cyfrowych o bardzo małej złożoności numerycznej. Jest ona...
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Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds
PublikacjaOne of the present trends in analytical chemistry is miniaturization, which is one of the methods of green analytical chemistry application. A particular emphasis is placed on the elimination of the use of large amounts of organic solvents which are toxic and harmful to the environment, maintaining high efficiency of the extraction process, high recovery values and low values of quantification (LOQ) and detection (LOD) limits....
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Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter
PublikacjaIn this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely...
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Solventless sample preparation techniques based on solid- and vapour-phase extraction
PublikacjaThe main objective of this review is to critically evaluate recent developments in solventless sample preparation techniques. The potential of a variety of sample preparation techniques based on solid- and vapour-phase extraction techniques is evaluated. Direct thermal extraction and derivatization processes to facilitate the extraction of analytes in different areas are included. The applicability, disadvantages and advantages...
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New sample preparation strategies for comprehensive lipidomics of human breast milk
PublikacjaGLOBAL PROFILING ANALYSIS OF HUMAN BREAST MILK (HBM) LIPIDS IS HINDERED BY COMPLEX COMPOSITION OF HBM. THIS PROBLEM IS HUGE FROM ANALYTICAL POINT OF VIEW, SINCE DUE TO THAT DETECTION OF ALL HBM LIPIDS DURING ONE ANALYTICAL RUN IS LIMITED. THUS, SAMPLE PREPARATION STEP CONSTITUTES A CRUCIAL STEP IN UNTARGETED LIPIDOMIC ANALYSIS OF HBM, ESPECIALLY WHEN SEMI-QUANTITATIVE ANALYSIS IS ASSUMED. HEREIN, WE PRESENT A COMPARISON OF PUBLISHED...
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Modern techniques of sample preparation for determination of organic analytes by gas chromatography
PublikacjaW pracy dokonano przeglądu szerokiego spektrum technik przygotowania próbki, ze szczególnym uwzględnieniem technik o charakterze prośrodowiskowym. Opisu technik dokonano pod kątem wykorzystywanych mechanizmów izolacji analitów oraz stosowanych rozwiązań aparaturowych. Przegląd rozwiązań aparaturowych uzupełniono o podstawy teoretyczne izolacji bazującej na zjawisku podziału analitów.
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Analytical applications of membrane extraction for biological and environmental liquid sample preparation
PublikacjaW niniejszej pracy przedstawiono informacje dotyczące technik ekstrakcji membranowej wykorzystywanych do oznaczania związków organicznych w ciekłych próbkach środowiskowych i biologicznych. Szczególną uwagę poświęcono podstawom teoretycznym tych technik, możliwości połączenia z technikami oznaczeń końcowych oraz obszarom praktycznego ich wykorzystania.
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Dynamic Headspace Sampling as an Initial Step for Sample Preparation in Chromatographic Analysis
PublikacjaThis work represents a brief summary of the use of dynamic headspace (DHS) as a technique for sample preparation in chromatographic analysis. Despite numerous developments in the area of analyte isolation and enrichment, DHS remains one of the fundamental methods used with GC. In our opinion, interest in this technique will not diminish significantly because it conforms to stipulations of green analytical chemistry. Moreover, DHS...
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SAMPLE-AND-HOLDING METHOD FOR GAS SENSING APPLIED FOR RESISTANCE GAS SENSORS
PublikacjaThe DC resistance of a Taguchi gas sensor is influenced by the ambient gas. To improve the selectivity and sensitivity of a sensor the fluctuation enhanced sensing (FES) was used. The paper proposes a novel methodology of utilizing FES technique that sample composition of an ambient atmosphere and hold it for further processing (sample-and-holding technique). The method uses the heated gas sensor to sample an ambient atmosphere...
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The estrogenicity of wastewater samples.
Dane BadawczeThe principle of operation of the kit is based on the fact that the tested sample with endocrine activity (containing compounds capable of binding to the human estrogen receptor α, hERα) releases the fluorescently labeled ligand (FluormoneTM ES2) from the receptor-ligand complex, which results in a reduction of the polarization value fluorescence. The...
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Evaluation of polycaprolactone as a new sorbent coating for determination of polar organic compounds in water samples using membrane–SPME
PublikacjaCommercially available solid-phase microextraction fibers used for isolation of polar analytes are based on the adsorption phenomenon. In consequence, typical limitations bonded with analytes displacement and matrix effects are very frequent. In the present study, alternative solution is described. Polycaprolactone (PCL) was used for the first time as sorbent to isolate polar organic compounds from water samples using the membrane–solid-phase...
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Development of the first internally-quenched fluorescent substrates of human cathepsin C: The application in the enzyme detection in biological samples
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Construction of an innovative adsorbent bed configuration in the adsorption chiller part 2. experimental research of coated bed samples
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Comparison of the Usefulness of SPE Cartridges for the Determination ofβ-Blockers andβ-Agonists (Basic Drugs) in Environmental Aqueous Samples
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Dimethyl(3,3,3-trifluoropropyl)silyldiethylamine—A new silylating agent for the derivatization of β-blockers and β-agonists in environmental samples
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Matrix effects and recovery calculations in analyses of pharmaceuticals based on the determination of β-blockers and β-agonists in environmental samples
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Monoterpenes emissions from different samples of wood-based materials – laminated chipboards and medium-density fiberboards (MDF)
PublikacjaThe paper presents the results of studies on emission rates of monoterpenes, carried out with the use of a new type of device - Markes’ Micro-Chamber/Thermal Extractor™ (μ-CTE250). Subject of studies were different types of wood-based materials such as: laminated chipboards and medium-density fiberboards (MDF). Based on the results obtained one can conclude that the laminated chipboards may affect the indoor air quality in much...
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Computer-aided analysis of signals from a low-coherence Fabry-Perot interferometer used for measurements of biological samples
PublikacjaThe aim of the study was to develop an automated computer-aided system for analysis of spectrograms obtained from measurements of biological samples performed with a low-coherence Fabry-Pérot interferometer. Information necessary to determine dispersion characteristics of measured materials can be calculated from the positions of the maxima and minima that are present in their spectra. The main challenge faced during the development...
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Application of ionic liquid-based microwave-assisted extraction of malachite green and crystal violet from water samples
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Application of Dispersive Liquid-Liquid Microextraction in Narrow-Bore Tube for Preconcentration and Spectrophotometric Determination of Cadmium in Aqueous Samples
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Rapid and sensitive determination of fluoride in toothpaste and water samples using headspace single drop microextraction-gas chromatography
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Determination of selected chemical parameters in surface water samples collected from the Revelva catchment (Hornsund fjord, Svalbard)
PublikacjaSurface water samples (river and lake) were collected from the Revelva catchment every summer from 2010 to 2013. This study concerns importance of the use of some analytical techniques for pollutants and parameters deter- mination in Arctic environmental samples based on the example of total organic carbon, phenols, and formaldehyde determination and measurement of pH and electrical conductivity parameters. Significant...
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The Antimicrobial Potential of Bacteria Isolated from Honey Samples Produced in the Apiaries Located in Pomeranian Voivodeship in Northern Poland
PublikacjaThe principal objective of this study was to determine whether the honeys produced in apiaries located in Pomeranian Voivodeship (Northern Poland) contain bacteria producing metabolites with growth inhibition potential against important human and animal pathogens. The pathogens included Staphylococcus aurues, Staphyloccocus epidermidis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Candida albicans. From...
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Correlation between chemical composition and the presence of selected groups of bacteria in freshwater samples collected from Isfjorden and Billefjorde
PublikacjaThe average concentrations of pollutants in the arctic water, snow and the atmosphere are much lower than those observed in the temperate climate. Specific conditions occurring in the polar regions have apotential to accumulate the pollutants transported from other parts of the world. In this study, attempts were made to find a correlation between selected chemical components and the bacterial population. The analysis involved...
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Application of ion chromatography with pulsed amperometric detection for the determination of trace cyanide in biological samples, including breast milk
PublikacjaCyanide (CN) is the biomarker of exposure to the components of tobacco smoke, although its presence in biological samples is also due to the consumption of products containing cyanogenic glycosides. In this work, we determine the concentration of the free cyanide in urine, saliva and breast milk matrices, using ion chromatography with pulsed amperometric detection (IC-PAD). IC-PAD is an emerging method, with only few documented...
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Automated high-capacity sorption probe for extraction of organic compounds in aqueous samples followed by gas chromatographic analysis.
PublikacjaOpracowano zautomatyzowany zestaw wyposażony w próbnik o dużej pojemności sorpcyjnej do oznaczania związków śladowych z zastosowaniem chromatografii gazowej. Zestaw łączy prostotę SPME z wysoką wydajnością techniki ekstrakcji z zastosowaniem ruchomego elementu sorpcyjnego (SBSE). Procedura pobierania próbek była przeprowadzana z zastosowaniem podajnika automatycznego. Ze względu na pełną automatyzację zestawu, możliwa jest bezobsługowa...
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Natural/bio-based sorbents as greener extractive materials for endocrine disrupting compounds in samples of different matrix composition
PublikacjaEndocrine-disrupting compounds (EDCs) are a group of chemicals that interfere with the endocrine system, leading to adverse effects on human health and the environment. Increasing concerns over the EDCs presence in various environmental compartments has driven the search for greener extraction materials. Recently, the use of polymers of natural origin (biopolymers) has been demonstrated to be an effective and promising research...
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Interspecific and intraspecific variation in organochlorine pesticides and polychlorinated biphenyls using non-destructive samples from Pygoscelis penguins
PublikacjaAs humans are present in Antarctica only for scientific and tourism-related purposes, it is often described as a pristine region. However, studies have identified measurable levels of Persistent Organic Pollutants (POPs), such as organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), in the Antarctic region. These are highly toxic anthropogenic compounds with tendency to travel long distances and reach remote environments, where...
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Comparative evaluation of different methods for determining phytochemicals and antioxidant activity in products containing betalains - Verification of beetroot samples
PublikacjaThis study presents methods that can be used to assess the health quality of products containing betalains. The paper compares and verifies data on the phytochemical composition of three different pigmented beetroot cultivars using spectrophotometric, HPLC-DAD, HPTLC and LC-Q-Orbitrap-HRMS techniques. Additionally, we compared the total antioxidant activity in both the cell-free and cellular systems. Betalain contribution to antioxidant...
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Deep eutectic solvent based method for analysis of Niclosamide in pharmaceutical and wastewater samples – A green analytical chemistry approach
PublikacjaThe paper presents a simple, but very effective and sensitive spectrophotometric method for trace analysis of Niclosamide based on liquid–liquid microextraction using deep eutectic solvents (DESs) prior to its quantification. Here, different DES systems, such as Choline chloride (ChCl) + Urea, ChCl + Citric acid, ChCl + Ethylene glycol and ChCl + Phenol, were synthesized and evaluated at different molar ratios, selecting ChCl + Phenol...
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Evaluation of Langmuir and Freundlich Isotherms for Removal of Cephalexin and Tetracycline Antibiotics By Sistan Sand from Water and Wastewater Samples
PublikacjaIn this research, Sistan sand was used as a natural and inexpensive sorbent for removal of cephalexin and tetracycline antibiotics from water and wastewater samples. For a concentration 60.0 mg L-1 of cephalexin, optimum removal conditions were: pH of the sample 3.0, adsorbent amount 1.0 g, contact time 20.0 min, added amount of sodium chloride to adjust the ionic strength of the solution 7.0 g L-1. Langmuir isotherm was the best...
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A solid phase extraction–ion chromatography with conductivity detection procedure for determining cationic surfactants in surface water samples
PublikacjaA new analytical procedure for the simultaneous determination of individual cationic surfactants (alkyl benzyl dimethyl ammonium chlorides) in surface water samples has been developed. We describe this methodology for the first time: it involves the application of solid phase extraction (SPE – for sample preparation) coupled with ion chromatography–conductivity detection (IC-CD – for the final determination). Mean recoveries of...
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Determination of thiocyanate (biomarkers of ETS) and other inorganic ions in human nasal discharge samples using ion chromatography
PublikacjaEnvironmental tobacco smoke (ETS) is a mixture of air and tobacco smoke containing more than 4000 chemical substances. In view of the health risks of many of these substances, studies are needed to determine biomarkers of exposure to ETS constituents in people who actively or passively are exposed to the toxic compounds. The methodologies for determining most biomarkers from saliva, urine and blood samples are known, but methods...
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Calibration of permeation passive samplers with silicone membranes based on physicochemical properties of the analytes.
PublikacjaW pracy opisano sposób kalibracji pasywnych dozymetrów permeacyjnych, wykorzystywanych w badaniach powietrza w oparciu o własności fizyko-chemiczne analitów. Stwierdzono silną zależność pomiędzy stałą kalibracyjną (K) dozymetrów i liczbą atomów węgla w cząsteczce analitu (w obrębie danej grupy związków chemicznych) dla alkoholi, alifatycznych i aromatycznych węglowodorów oraz estrów. Taka zależność występuje również pomiędzy...
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Uralic linguistic terminology: selected problems and examples
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Examples of Original Descriptive Geometry Task Items
PublikacjaThe paper presents several descriptive geometry drawing tasks and a comprehensive approach to their evaluation. The results as the task profile include the most important features and enable interpretation of the tasks in the educational system.
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Modelling of bio-mechanical objects: recent examples
PublikacjaW opracowaniu przedstawiono dwa wykorzystania modelowania bio-mechanicznego wybranych obiektów: modelowanie zachowania mięśni w układzie ramię-przedramię oraz wstępny projekt protezy dłoni przy użyciu materiałów z pamięcią kształtu. Przedstawiono wyniki badań symulacyjnych oraz opis dynamiki działania układów sterowania dla protezy dłoni oraz dla układu ramię-przedramię.
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A simple test for quantum channel capacity
PublikacjaBased on state and channel isomorphism we point out that semidefiniteprogramming can be used as a quick test for nonzero one-way quantum channelcapacity. This can be achieved by searching for symmetric extensions of statesisomorphic to a given quantum channel. With this method we provide examplesof quantum channels that can lead to high entanglement transmission but stillhave zero one-way capacity, in particular, regions of symmetric...
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A simple model of circular hydraulic pump
PublikacjaRozpatrzono warunki powstawania osiowosymetrycznego uskoku hydraulicznego. Przedstawiono model, w którym rozpatrzono obecność dodatkowych strat w równaniu Bernoulliego. Przyczyniają się one do powstawania dodatkowego wiru w miejscu uskoku. Porównanie z wynikami badań eksperymentalnych potwierdza słuszność przyjętych tez.
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Proton affinities of simple organic compounds
PublikacjaThe Restricted Hatree-Fock method with 6-311G** split-valence molecular orbitals basis sets has been applied to geometrical optimizations and calculations of total electronic, zero point vibrational energies and proton affinities at 298 K for small neutral and protonated alkanes, alcohols, acetic acid, methyl and ethyl acetate, acetone, and acetaldehyde. Calculated values of proton affinities are compared with experimental data.
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A simple high-accuracy subgridding scheme
PublikacjaArtykuł wprowadza nową metodę włączania obszarów o gęstszej siatce w metodzie różnic skończonych w dziedzinie czasu. Obszary o różnych gęstościach siatki łączone są poprzez prostą interpolację pola elektrycznego i magnetycznego. Metoda wymaga nieparzystego współczynnika zagęszczenia i daje niskie współczynniki odbicia od zagęszczonych obszarów zwiększając dokładność obliczeń FDTD i jednocześnie skracając czas obliczeń. Prezentowane...
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A simple access to o-acyl bicyne
PublikacjaW publikacji przedstawiono prostą metodę otrzymywania o-acylowych pochodnych bicyny. Substratem do syntezy była n,n-bis(2-hydroksyetylo)glicyna - bicyna. Bicynę najpierw przeprowadzano w ester benzylowy w reakcji z alkoholem benzylowym i kwasem p-toluenosulfonowym w temp. 75 st. C. Tak otrzymany związek, acylowano kwasami organicznymi w obecności DCC ( dicyklokeksylokarbodiimid)i DMAP (dimetyloaminopirydyna), otrzymując o-acylowe...
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Simple SIR models with Markovian control
PublikacjaWe consider a random dynamical system, where the deterministic dynamics are driven by a finite-state space Markov chain. We provide a comprehensive introduction to the required mathematical apparatus and then turn to a special focus on the susceptible-infected-recovered epidemiological model with random steering. Through simulations we visualize the behaviour of the system and the effect of the high-frequency limit of the driving...
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Simple measure of typewriter prints quality
PublikacjaArtykuł przedstawia opracowaną przez autora metodę określania kształtu zaadaptowaną do szacowania jakości znaków uzyskiwanych na maszynie do pisania. Metoda ta bazuje na statystycznej analizie odwzorowania maksymalnego kwadratu (ang. Maximal Square Map) opisanej w szczegółach w artykule. Metodę opracowano celem szacowania jakości komputerowo wspomaganego pozyskiwania informacji z archiwalnych maszynopisów.
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Update a simple hypoplastic constitutive model
PublikacjaW artykule omówiono uproszczona formę hipoplastycznego konstytutywnego prawa materiałowego do opisu zachowania się materiałów granulowanych. Wykonano symulacje testów elementów i porównano wyniki z doświadczeniami.