Filters
total: 7194
filtered: 1167
displaying 1000 best results Help
Search results for: TD-SFEM
-
Gradient-based optimization of filters using FD-TD software
PublicationW artykule opisane jest nowe podejście do zagadnienia optymalizacji filtrów mikrofalowych pasmowo-przepustowych. Optymalizacja prowadzona jest z wykorzystaniem metody gradientowej poszukiwania minimum wartości funkcji celu oraz przy założeniu pełnofalowej symulacji obwodów metodą różnic skończonych w dziedzinie czasu. W artykule pokazane jest, że stosując zaawansowane techniki cyfrowego przetwarzania sygnałów możliwa jest optymalizacja...
-
Low-order models from FD-TD time samples
PublicationNiniejszy artykuł zawiera opis szeregu kryteriów pozwalających na automatyczne tworzenie wysokiej jakości modeli sygnałów czasowych uzyskanych w drodze symulacji obwodów wysokiej częstotliwości metodą różnic skończonych w dziedzinie czasu. Podany jest szczegółowy opis selekcji kluczowych parametrów modeli takich jak wybór długości ciągu użytego do konstrukcji modeli, współczynnika decymacji silnie nadpróbkowanego przebiegu w dziedzinie...
-
The application of TD-GC-FID technique for production of matrix-free reference materials
PublicationIn the last few years particular pressure is exerted on finding new analytical methods which would provide real possibilities of monitoring and control of the state of the environment. Intensive development of analytical techniques for measurements of gaseous media and the negative effects of BTX compounds make it necessary to produce new gaseous reference materials. To prepare the appropriate non- matrix reference material thermal...
-
Determination of odour concentration by TD-GC×GC–TOF-MS and field olfactometry techniques
PublicationField olfactometry is one of the sensory techniques used to determine odour concentration, in atmospheric air, directly in emission sources. A two-dimensional gas chromatography with time of flight mass spectrometer (GC×GC–TOF-MS) allows performing the chemical characterization of various groups of chemical compounds, even in complex mixtures. Application of these techniques enabled determination of odour concentration level in...
-
Optimization of a novel procedure for determination of VOCs in water and human urine samples based on SBSE coupled with TD-GC-HRMS.
PublicationPodczas ozanczania lotnych związków chlorowcoorganicznych (t.j. bromodichlorometanu, dibromochlorometanu, bromoformu I tetrachloroetylenu) z próbek wody I moczu ludzkiego wykorzystano technikę ekstrakcji za pomocą ruchomego elementu sorpcyjnego typu Twister połączonego z desorpcją termiczną analitów do kolumny chromatografu gazowego wyposażonego w wysokosprawny spektrometr mas. Przeprowadzono optymalizację czasu (30 min) i prędkości...
-
Core–shell excitation of isoxazole at the C, N, and O K-edges – an experimental NEXAFS and theoretical TD-DFT study
PublicationThe near-edge X-ray absorption fine structure (NEXAFS) spectra of the gas-phase isoxazole molecule have been measured by collecting total ion yields at the C, N, and O K-edges. The spectral structures have been interpreted using time-dependent density functional theory (TD-DFT) with the short-range corrected SRC2-BLYP exchange–correlation functional. Experimental and calculated energies of core excitations are generally in good...
-
Influence of orientational disorder on the optical absorption properties in hybrid metal‐halide perovskite CH3NH3PbI3. A combined DFT/TD‐DFT and experimental study.
PublicationAn experimental and theoretical investigation is reported to analyze the relation between the structural and absorption properties of CH3NH3PbI3 in the tetragonal phase. More than 3000 geometry optimizations were performed in order to reveal the structural disorder and to identify structures with the lowest energies. The electronic structure calculations provide an averaged band gap of 1.674 eV, which is in excellent agreement...
-
A DFT/TD DFT study of the structure and spectroscopic properties of 5-methyl-2-(8-quinolinyl)benzoxazole and its complexes with Zn(II) ion
Publication -
Theoretical designing of selenium heterocyclic non-fullerene acceptors with enhanced power conversion efficiency for organic solar cells: a DFT/TD-DFT-based prediction and understanding
PublicationIn this study, we have designed and explored a new series of non-fullerene acceptors for possible applications in organic solar cells. We have designed four molecules named as APH1 to APH4 after end-capped modification of recently synthesized Y6-Se-4Cl molecule. Density functional theory and time dependent-density functional theory have been employed for computing geometric and photovoltaic parameters of the designed molecules....
-
SFEM Analysis of Beams with Scaled Lengths including Spatially Varying and Cross-Correlated Concrete Properties
PublicationThis paper presents the results obtained for plain concrete beams under four-point bending with spatially varying material properties. Beams of increasing length but constant depth were analyzed using the stochastic finite element method. Spatial fluctuation of a uniaxial tensile strength, fracture energy and elastic modulus was defined within cross-correlated random fields. The symmetrical Gauss probability distribution function...
-
Cellular Interactions in the Intestinal Stem Cell Niche
Publication -
A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
PublicationIn this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries...
-
New procedure of silica gel surface modification-preparation of gaseous standard mixtures of methyl chloride using the technique of thermal decomposition of the surface compound for calibration of a TD-GC-FID system.
PublicationPrzedstawiono nową procedurę modyfikacji powierzchni żelu krzemionkowego w celu wytworzenia związku powierzchniowego będącego źródłem chlorku metylu. Minimalna temperatura rozkładu (150 st. C) zapewnia trwałość chemicznie modyfikowanego złoża w temp. pokojowej. Badania prowadzono w temperaturze optymalnej (280 st.C). Stwierdzono, że powierzchnia żelu jest obsadzona jednorodnie przez związek powierzchniowy i gazowa mieszanina wzorcowa...
-
COVID-19: Plasma Therapy and Stem Cell Therapy
Publication -
Mobilization of Stem and Progenitor Cells in Septic Shock Patients
Publication -
Individual entrepreneurial orientation: comparison of business and STEM students
PublicationAbstract Purpose – The purpose of this study is to determine whether there are differences in Individual Entrepreneurial Orientation (IEO) between students who are doing their major in business studies and the ones whose areas of study are science, technology, engineering, and mathematics (STEM). Design/methodology/approach – The current research investigates which factors and components contribute to EO orientation development...
-
Cancer stem cells in drug resistance and drug screening: can we exploit the cancer stem cell paradigm in search for new antitumor agents?
PublicationPraca przedstawia przegląd literatury dotyczącej hipotezy komórek pierwotnych nowotworu, w szczególności w ich oporności na istniejące terapie. Dyskutowane jest także zagadnienie możliwości wykorzystania wiedzy o tych komórkach do konstrukcji nowych testów do badań przesiewowych in vitro w celu poszukiwania nowych leków przeciwnowotworowych.
-
Serum levels of stem cell factor for predicting embryo quality
Publication -
Macromodels for efficient FEM simulations of waveguides and resonators
PublicationThis paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple...
-
Modal FEM Analysis of Ferrite Resonant Structures
PublicationThe finite-element method (FEM) is applied for modal analysis of ferrite-loaded spherical resonators. To improve the efficiency of the numerical calculations, the body-of-revolution (BOR) technique is utilized. Due to the frequency-dependent ferrite permeability, FEM leads to a nonlinear eigenvalue problem that is challenging to solve. To this end, Beyn’s method is proposed. The effectiveness of the proposed approach is confirmed...
-
Study of displacements of a bridge abutment using FEM
PublicationSteel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented...
-
CFD and FEM model of an underwater vehicle propeller
PublicationDuring the project execution of design and optimization the Remotely Operated Vehicle (ROV) research on its propulsion has been carried out. The entire project was supported by CFD and FEM calculations, which taking into account the characteristics of underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to...
-
FEM approach to modeling of an irregular trabecular structure
PublicationThe aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the...
-
A two-scale (FEM-DEM) approach for concrete
PublicationArtykuł omawia dwu-skalowe podejście do betonu przy wykorzystaniu modelu Mes i DEM. Metodę elementów skończonych zastosowano na poziomie makro. Na poziomie mikro zastosowano metodę elementów dyskretnych. Macierz sztywności wyznaczono na podstawie tensora naprężeń wyznaczonego w skali mikro. Wyniki numeryczne dwusalowe porównano z wynikami dyskretnymi dla całego obszaru.
-
Flow cytometric sorting and analysis of human epidermal stem cell candidates
Publication -
DEM-FEM model of highly saturated soil motion due to seepage force
PublicationArtykuł poświęcono nowej propozycji rozwiązania problemu modelowania zjawiska transportu, które występuje wewnątrz wysoko-nawodnionego gruntu ziarnistego na skutek ciśnienia spływowego. Teoria oparta została na połączeniu metody elementów skończonych (FEM - Finite Element Method) - rozwiązania równań poro-elastycznych oraz metody poszczególnych elementów (DEM - Distinct Element Method), które dały podwójny model numeryczny. FEM...
-
Torsional Stability Assessment of Columns Using Photometry and FEM
Publication -
FEM modelling of screw displacement pile interaction with subsoil
PublicationPredicting the-settlement characteristics of piles is an important element in the designing of pile foundations. The most reliable method in evaluating pile-soil interaction is the static load test, preferably performed with instrumentation for measuring shaft and pile base resistances. This, however, is a mostly post-implementation test. In the design phase, prediction methods are needed, in which numerical simulations play an...
-
Young’s modulus distribution in the FEM models of bone tissue
PublicationThis paper presents how differences of Young’s modulus in adjacent finite elements typical for organic materials such as bone tissue, influence stress calculating. Emphasizing high computational cost of variable Young’s modulus in parts of the model, where the number of finite elements has been raised, the authors wants to prove that new model of finite element which has variable Young’s modulus in its volume needs to be created....
-
FEM simulation of laminate failure in the three point bending
PublicationThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...
-
Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublicationUltrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...
-
From chemoresistance to cancer stem cells: the case of BRCP/ABCG2 half transporter
PublicationLudzkie białko ABCG2 jest pompą typu ABC tworzącą homodimery i aktywnie transportującą leki i inne substraty naturalne i syntetyczne. Nadekspresja tego białko prowadzi do oporności na leki przeciwnowotworowe. Białko ABCG2 występuje w wielu formach zmutowanych, różniących się własnościami substratowymi, stąd istotne dla oporności na leki jest jaka forma genu i białka ABCG2 ulega nadekspresji w komórce. Ostatnie badania wskazują,...
-
The Use of Stem Cells as a Potential Treatment Method for Selected Neurodegenerative Diseases: Review
Publication -
Nucleotides metabolizing ectoenzymes as possible markers of mesenchymal stem cell osteogenic differentiation
Publication -
Human amniotic-fluid-derived stem cells: a unique source for regenerative medicine
Publication -
Artificial-Intelligence-Based Imaging Analysis of Stem Cells: A Systematic Scoping Review
Publication -
Evaluation of Open Source SIEM for Situation Awareness Platform in the Smart Grid Environment
PublicationThe smart grid as a large-scale system of systems has an exceptionally large surface exposed to cyber-attacks, including highly evolved and sophisticated threats such as Advanced Persistent Threats (APT) or Botnets. When addressing this situation the usual cyber security technologies are prerequisite, but not sufficient. The smart grid requires developing and deploying an extensive ICT infrastructure that supports significantly...
-
Caffeine Inhibits Differentiation Of Lung Cancer Stem Cells By Modulating Their Respiratory Metabolism
PublicationIt is ell established that many tumor types contain a fraction of cells, with stem cell-like properties, called cancer stem cells (CSCs), that are resistant to apoptosis induced by therapeutic agents. The presence of CSCs may explain why a standard anticancer treatment, that eliminates only differentiated cancer cells, does not lead to cancer cure.We previously showed the existence of caffeine-sensitive mechanism that controls...
-
VOF-DEM-FEM combined model of the reef breakwater collapse
PublicationZespolony model numeryczny (metoda modelowania przepływu ze swobodną powierzchnią rozdziału faz ciekłej i gazowej w siatce nieruchomej (ang. Volume of Fluid - VOF, metoda elementów dyskretnych (ang. Distinct Element Method, metoda elementów skończonych (MES)) został wykorzystany do zbadania odkształceń falochronu narzutowego i jego piaszczystego podłoża w wyniku oddziaływania falowania powierzchniowego. Wyniki analizy numerycznej...
-
FEM modeling of structures based on close range digital photogrammetry
PublicationPraca dotyczy metodologii przygotowania modelu konstrukcji istniejącej do analizy mechanicznej metodą element ow skończonych. MOdelowanie geometrii budowli jest oparte na danych pozyskanych z pomiarów fotogrametrycznych. Praca wskazuje na możliwości oraz efektywność zastosowania metod optometrycznych w rewitalizacji budowli zabytkowych, an przykładzie modelu dachu drewnianego.
-
FEM strength analysis of sandwich panels for ship structure applications
PublicationW publikacji zaprezentowano wyniki analizy numerycznej stalowego panelu sandwich obciążonego siłami ściskającymi wzdłuż laserowo spawanych usztywnień. Przedstawiono sposób modelowania, pokazano i przedyskutowano uzyskane rezultaty.
-
Prediction of the properties of PVD/CVD coatings with the use of FEM analysis
Publication -
Some theoretical models of technical woven fabric and their use in FEM.
PublicationCelem pracy było przedstawienie niektórych typów równań konstytutywnych opisujących zachowanie powłok membranowych używanych do konstrukcji przekryć wiszących. Ocena zastosowanego modelu izotropowego i sieci gęstej w analizie tkanin technicznych. Dokonano porównania wyników uzyskanych własnymi algorytmami metody elementów skończonych z powszechnie dostępnym na rynku programem komercyjnym MARC firmy MSC. Uzyskano dobrą zgodność...
-
On the FEM implementation of the large rotation shell theory for elasticanisotropic shells.
PublicationW pracy przedstawiono problemy implementacji MES teorii powłok o dużych obrotach w statycznej, geometrycznie nieliniowej analizie konstrukcji warstwowych. Zwrócono uwagę na właściwą interpretacje rotacyjnych stopni swobody w algorytmie MES. Omówiono wariant dużych i skończonych obrotów. Przedstawiono wyniki obliczeń dla znanego w literaturze przykładu analizy paneli kompozytowej w zakresie dużych obrotów.
-
Electromagnetic Simulations with 3D FEM and Intel Optane Persistent Memory
PublicationAbstract—Intel Optane persistent memory has the potential to induce a change in how high-performance calculations requiring a large system memory capacity are conducted. This article presents what this change may look like in the case of factorization of large sparse matrices describing electromagnetic problems arising in the 3D FEM analysis of passive highfrequency components. In numerical tests, the Intel oneAPI MKL PARDISO was...
-
Effect of mesh deformation on the accuracy of 3D FEM electromagnetic analysis
PublicationIn this paper, the accuracy of 3D FEM electromagnetic simulations in parametric analysis using mesh deformation techniques is discussed. Mesh deformation techniques allow one to preserve the mesh topology while the geometry is changed. It is shown that the application of mesh deformation can provide accurate simulation results even for very large deformations. On the other hand, it is also shown that the technique has to be used...
-
Elastoplastic nonlinear FEM analysis of FGM shells of Cosserat type
PublicationThe paper is a continuation of [1] where the formulation of the elastic constitutive law for functionally graded materials (FGM) on the grounds of nonlinear 6-parameter shell theory with the 6th parameter (the drilling degree of freedom) was presented. Here the formulation is extended to the elasto-plastic range. The material law is based on Cosserat plasticity and employs the well-known Tamura-Tomota-Ozawa (TTO) [2] mixture...
-
FEM ANALYSIS AND EXPERIMENTAL TESTS OF RIGID RISER HANGING SYSTEM
PublicationThe article presents the analysis, project, and experimental examination of an original rigid riser for Coil Tubing Pipes. The principle of riser operation is based on the use of friction forces. The research included the FEM analysis of the designed riser, calculations of the required bolt tensions, and checking the effect of the clamping force on stress distribution in the pipeline. The results of computer simulation were verified...
-
Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
PublicationElectromagnetic simulation and electronic design automation (EDA) play an important role in the design of 5G antennas and radio chips. The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method (FEM). The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis, but...
-
Comparative modeling of shear localization in granular bodies with FEM and DEM
PublicationThe intention of the paper is to compare the calculations of shear zones in granular bodies using two different approaches: a continuum and a discrete one. In the first case, the FEM based on a micro-polar hypoplastic constitutive law was used. In the second case, the DEM was taken advantage of, where contact moments were taken into account to model grain roughness. The comparative calculations were performed for a passive case...