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Search results for: qm/mm calculations
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Linear-scaling calculation of Hartree-Fock exchange energy with Non-orthogonal Generalised Wannier Functions
PublicationWe present a method for the calculation of four-centre two-electron repulsion integrals in terms of localised non-orthogonal generalised Wannier functions (NGWFs). Our method has been imple- mented in the ONETEP program and is used to compute the Hartree-Fock exchange energy component of Hartree-Fock and Density Functional Theory (DFT) calculations with hybrid exchange-correlation functionals. As the NGWFs are optimised in situ...
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Application of the laser diode with central wavelength 975 nm for the therapy of neurofibroma and hemangiomas
PublicationThis paper presents newly developed dermatological laser (with central wavelength 975 nm) for application in therapies requiring deep penetration of tissue, e.g. cutaneous (dermal) neurofibroma (Recklinghausen disease) and hemangiomas. This laser can work either in pulse or continues wave mode. Laser radiation is transmitted toward the application region by optical fiber with a diameter of 0.6 mm. The compact design of the laser...
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Grinding of cemented carbides with planetary kinematics
PublicationW pracy przeprowadzono wyniki badań szlifowania z wykorzystaniem nowoczesnej szlifierki planetarnej DLM 505 HS. Zastosowano jednolite narzędzie wykonane z ziarna diamentowego D107. W artykule wyprowadzono podstawowe równania ruchu w układzie planetarnym. Przedstawiono również wartości parametrów chropowatości, ubytku materiałowego i płasko-równoległości po szlifowaniu przedmiotów wykonanych z węglików spiekanych - HF10, D10x8 mm.
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Pool boiling of water-Al2O3 nanofliud on horizontal porous coated tube
PublicationPrzedstawiono wyniki badań przejmowania ciepła podczas wrzenia w dużej objętości nanocieczy woda-Al2O3 na poziomej rurce z aluminiową powłoką porowatą o grubości 0.15 mm i porowatości 40%. Koncentracja nanocząstek wnosiła 0.01%, 0.1% oraz 1%. Niezależnie od koncentracji współczynnik przejmowania ciepła przy wrzeniu nanocieczy był niższy niż przy wrzeniu wody destylowanej.
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Positron Scattering and Annihilation in Organic Molecules
PublicationIn this paper, we address the problem of connecting positron lifetimes in liquids with collision cross sections in gases. We present the analyses of annihilation lifetime spectra of positrons in the liquid benzene, c-hexane, n-hexane, methanol and ethanol and calculations of scattering cross sections of positrons with benzene and c-hexane in the gas phase.
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Thermal and hydraulic phenomena in boundary layer of minijets impingement on curved surfaces
PublicationPresented work considers flow and thermal phenomena occurring during the single minijet impingement on curved surfaces, heated with a constant heat flux, as well as the array of minijets. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted, regarding single phase and two-phase simulations. Focus was placed on the proper model construction, in which turbulence and boundary layer modeling...
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Modeling process of planning finished product sales volumes at industrial enterprises in modern economic conditions
PublicationThis article presents improving the existing system of planning finished products sales volumes. The influencing factors of the sales volumes in modern economic conditions have been determined: falling world oil prices, the reduction of pipe consumption in the domestic market, the global pandemic. The algorithm of planning finished products sales volumes has been constructed. Calculations based on the Holt forecasting method has...
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Analysis of ring cracks in ceramic rolling elements using the boundary element method
PublicationCeramic materials have been increasingly used in bearing technology for over a dozen years. This is due to the characteristic properties of ceramic materials such as: high hardness, corrosion resistance, the possibility of use in aggressive chemical environments, as well as due to the lower specific weight compared to steel materials. However, the use of ceramic materials is connected with many limitations. The main disadvantages...
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Low-energy positron scattering from gas-phase benzene
PublicationIn this paper we are presenting calculations of the elastic cross section of positrons with gas-phase benzene for the energy range from 0.25 eV to 9.0 eV. The calculations are done with the molecular R-matrix method for positron-scattering from poly-atomic molecules using a scaling factor to scale the electron-positron interaction. The scaling factor influences the position of the poles of the R-matrix. We adjust the scaling factor...
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Analysis of hydrodynamic pressure fields of motorboats and pontoons in shallow water
PublicationThe article presents the results of calculations of the pressure fields generated by a motorboat at the bottom of a shallow sea. Calculations were made using the boundary elements method (BEM), arranged on the surface of the boat and the bottom of the sea. This method is described in [3], and applied on a free surface linearized boundary condition. Results for four different lengths of motorboats, from 2.85 m to 9.5 m, sea depth...
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Quantitative Analysis of Biofilm Formed on Vascular Prostheses by Staphylococcus Epidermidis with Different ica and aap Genetic Status
PublicationOBJECTIVES: This study aims to examine biofilm formed on vascular prostheses by Staphylococcus epidermidis with different ica and aap genetic status, and to evaluate the effect of antibiotic-modified prostheses on bacterial colonization. METHODS: Biofilm formation was determined using fluorescence microscopy imaging. Quantitative analysis was conducted using the biofilm coverage ratio (BCR) calculations. RESULTS: Our investigations...
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Magnetic and capacitive couplings influence on power and energy measurement in double circuit high voltage overhead transmission line
PublicationThe paper discusses influence of magnetic and capacitive couplings on power and energy measurement in case of double circuit high voltage overhead transmission line. There are presented and discussed various factors influencing the power flow among the line‟s circuits. Mathematical model based calculations results are compared to the real transmission line measurements.
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CLICK 'n' Sleep: Light-Switch Behavior of Triazole-Containing Tris(bipyridyl)ruthenium Complexes
PublicationA set of RuII complexes incorporating triazole subunits are presented. They show a solvent-dependent light-switch effect. Theoretical calculations revealed the excited states involved in the emission process. The findings are highly important for future design of light-switch sensors and suggest a severe restriction for functional photomolecular devices synthesized by CLICK chemistry.
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Wpływ kierunku rozchodzenia się fali detonacyjnej oraz współczynnika asymetrii na rozkład prędkości odkształceń w kotlinie walcowniczej podczas asymetrycznego walcowania pasma Al-Cu. The influences of the direction of explosion wave and asymetrical coefficient at the distribution of strain rate in the roll cap of bimetallic plate Al-Cu of rolling process.
PublicationPrzedstawiono symulacje komputerowe walcowania blach Al-Cu łączonych wybuchowo. Symulacje przeprowadzono dla procesu walcowania w walcarce o średnicy walców D=150 mm z indywidualnym napędem walców roboczych. W ramach badań numerycznych określony został wpływ kierunku rozchodzenia się fali detonacyjnej na rozkład prędkości odkształcenia w kotlinie walcowniczej asymetrycznie walcowanej blachy bimetalowej Al-Cu.
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Analiza odcinków generujących straty czasu w transporcie tramwajowym
PublicationW czasie analiz i studiów przedwykonawczych dotyczących budowy nowych i modernizacji istniejących tras tramwajowych, bardzo często zakładane są nierealne czasy przejazdów, które weryfikuje się już po oddaniu linii do eksploatacji i przeprowadzeniu badań obserwacyjnych. Problematyczne wydaje się określenie, przed zakończeniem inwestycji, rzeczywistej prędkości jazdy, jak również strat czasu powstających w miejscach potencjalnych...
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Fusion of Taq DNA polymerase with single-stranded DNA binding-like protein of Nanoarchaeum equitans—Expression and characterization
PublicationDNA polymerases are present in all organisms and are important enzymes that synthesise DNA molecules. They are used in various fields of science, predominantly as essential components for in vitro DNA syntheses, known as PCR. Modern diagnostics, molecular biology and genetic engineering need DNA polymerases which demonstrate improved performance. This study was aimed at obtaining a new NeqSSB-TaqS fusion DNA polymerase from the...
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Modelowanie propagacji fal sprężystych w węzłach spawanych konstrukcji stalowych
PublicationCelem pracy było wykonanie numerycznych modeli spawanych węzłów konstrukcji stalowych poddanych krótkotrwałym sinusoidalnym wzbudzeniom o wysokich częstotliwościach rzędu 100-200 kHz, symulujących propagację fal sprężystych w ciałach stałych oraz opracowanie wskaźnika pozwalającego na ocenę ewentualnych uszkodzeń występujących w węźle konstrukcji. Model numeryczny opracowano przy użyciu metody elementów skończonych. Jako przykład...
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Aktywność amylolityczna ciałek inkluzyjnych izolowanych z Escherichia coli BL21(DE3)pLysS transformowanej plazmidem pTYB2alfa-Amyl.
PublicationBadania ekspresji rekombinantowej alfa-amylazy izolowanej z Escherichia coli BL21(DE3)pLysS transformowanej plazmidem pTYB2alfa-Amyl wykazały, że około 49 % wytwarzanego enzymu występuje w postaci ciałek inkluzyjnych. Źródłem genu termostabilnej alfa-amylazy był szczep Pyrococcus woesei (DSM 3773). W celu uzyskania aktywnych białek z ciałek inkluzyjnych odwirowane komórki bakterii inkubowano w roztworze CaCl2 i po trawieniu lizozymem...
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Influence of the thermal modernization of window on transmission heat losses
PublicationThe article presents the results of calculations of the heat transfer coefficient for the state before and after renovation for the historic windows. The aim of the analysis was to obtain the values of thermal insulation parameters demanded by the regulations, while not losing the historical value of the window. The described example of the renovation of the existing window consisted in installing an additional window panel from...
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Flow boiling intensification in minichannels by means of mechanical flow turbulising inserts
PublicationThe work presents the results of experimental investigation on heat transfer in minichannels. Refrigerant R123 was used as a test fluid. Single vertical silver tubes of 380 mm length and 2.3 mm diameter were examined with two variants of turbulising inserts. A wide range of parameters was considered, namely mass flux G=534-3011 kg/(m2s), heat flux qw=28.5-68.4 kW/m2, saturation temperature Tsat=23-86 stC and the full range of vapour...
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Effect of Tool Positioning Factors on the Strength of Dissimilar Friction Stir Welded Joints of AA7075-T6 and AA6061-T6
PublicationFriction Stir Welding (FSW) is a solid-state bonding technique. There are many direct and indirect factors affecting the mechanical and microstructural properties of the FSW joints. Tool offset, tilt angle, and plunge depth are determinative tool positioning in the FSW process. Investigating the effect of these factors simultaneously with other parameters such as process speeds (rotational speed and translational speed) and tool...
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Numerically Efficient Miniaturization-Oriented Optimization of an Ultra-Wideband Spline-Parameterized Antenna
PublicationDesign of ultra-wideband radiators for modern handheld applications is a challenging task that involves not only selection of an appropriate topology, but also its tuning oriented towards balancing the electrical performance and size. In this work, a low-cost design of a compact, broadband, spline-parameterized monopole antenna has been considered. The framework used for the structure design implements trust-region-based methods,...
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Stress–strain model of lower corroded steel plates of normal strength for fitness-for-purpose analyses
PublicationThis study investigates the mechanical properties of specimens made of normal strength steel subjected to lower marine immersed corrosion degradation levels (below 25 %). The specimens were corroded in laboratory conditions, and only natural factors were controlled to raise the corrosion rate (reaching the level of 1 mm/year). Three different thicknesses of plates made of normal strength of shipbuilding steel are investigated (between...
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A Series-Inclined-Slot-Fed Circularly Polarized Antenna for 5G 28-GHz Applications
PublicationThis letter presents the design of a single-point-fed, geometrically simple circularly polarized (CP) antenna for 28 GHz Ka-band applications. The proposed antenna is based on a straight microstrip line printed on one side and coupled with the nearly square patches through a 45-degree inclined V-shape slot aperture on the other side. In order to generate circular polarization, the fundamental radiating mode is degenerated at a...
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Artificial Thermal Ageing of Polyester Reinforced and Polyvinyl Chloride Coated Technical Fabric
PublicationArchitectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed method is based on the accelerated ageing approach proposed by Arrhenius. 300 mm x 50 mm samples were cut in the warp and fill directions and placed in a thermal chamber at 80 °C for up to 12 weeks or at 90 °C for up to 6 weeks. Then after one week of conditioning at ambient temperature,...
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The Impact of Spatiotemporal Changes in Land Development (1984–2019) on the Increase in the Runoff Coefficient in Erbil, Kurdistan Region of Iraq
PublicationNowadays, geospatial techniques are a popular approach for estimating urban flash floods by considering spatiotemporal changes in urban development. In this study, we investigated the impact of Land Use/Land Cover (LULC) changes on the hydrological response of the Erbil basin in the Kurdistan Region of Iraq (KRI). In the studied area, the LULC changes were calculated for 1984, 1994, 2004, 2014 and 2019 using the Digital Elevation...
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Charakterystyka wybranych właściwości mikrosfer - frakcji popiołu lotnego - ubocznego produktu spalania węgla kamiennego
PublicationMikrosfery - drobna frakcja popiołów lotnych - powstają w procesie konwencjonalnego spalania węgli kamiennych. Ich zawartość w popiołach lotnych ze spalania różnych gatunków węgla zmieniać się może w szerokim zakresie: od 0,01 do 35,6 wag.%. Pod względem składu chemicznego, głównymi składnikami mikrosfer w formie tlenkowej jest krzem, glin i żelazo, stanowiące około 89% ich masy. Ich skład mineralny stanowią głównie kwarc i mulit....
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Homoisocitrate dehydrogenase from Candida albicans: properties, inhibition, and targeting by an antifungal pro-drug
PublicationThe LYS12 gene from Candida albicans, coding for homoisocitrate dehydrogenase was cloned and expressed as a His-tagged protein in Escherichia coli. The purified gene product catalyzes the Mg2+- and K+-dependent oxidative decarboxylation of homoisocitrate to alpha-ketoadipate. The recombinant enzyme demonstrates strict specificity for homoisocitrate. SDS-PAGE of CaHIcDH revealed its molecular mass of 42.6±1 kDa, while in size-exclusion...
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Moisture content during and after high- and normal-temperature drying processes of wood
PublicationThe aim of the article is to present the results of moisture content of wood during and after the high-temperature steam and air–steam mixture drying processes and after an open air-drying process. The knowledge of moisture content changes of wood in the process of its drying is one of the important parameters to economy drying process and to keep the quality of dried wood. Wood samples, namely, spruce (Picea abies K.) and beech...
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Analysis of magnetic field inside thin-layer ferromagnetic objects
PublicationResults of the numerical analysis of the magnetic field inside an infinitely long, thin-layer ferromagnetic pipe with and without a barrier were presented in this paper. Two wires with current symmetrically placed on two sides of the pipe are the sources of magnetic field. Numerical calculations for the quasi-steady state for chosen frequency band were carried out in the Flux 2D.
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Applying of thin plate boundary condition in analysis of ship’s magnetic field
PublicationThis paper presents computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera-3d 18R2 program. The paper aims to check the magnetic signatures’ numerical calculations precision of objects using the thin plate boundary conditions and analysis of the magnetic signature of ship with a degaussing system and with and without inner devices.
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Digital Photogrammetry in the Analysis of the Ventricles' Shape and Size
PublicationThis article presents spatial analyzes conducted to assess the potential of ReMake software to be used for medical purposes, with emphasis on the analysis of the shape and dimensions of the ventricles. To achieve this goal, the length of the sections measured with the ReMake and Image Master programs have been compared. RMS error was on the level of 1.2 mm. In addition to indicating the appropriateness of using this software, there...
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Optymalizacja mikrofalowego generatora plazmy o strukturze współosiowej zasilanego falowodem
PublicationW niniejszym artykule przedstawiono wyniki optymalizacji transferu energii w mikrofalowym generatorze plazmy o strukturze współosiowej zasilanym falowodem WR 340. Do obliczeń posłużono się programem Comsol Multiphysics. Dla zwartego odcinka linii współosiowej o optymalnej długości 52 mm, minimalny stosunek mocy fali odbitej do mocy fali padającej mierzony w płaszczyźnie wejściowej prezentowanego generatora plazmy zmniejszył się...
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Kompozyty poliuretanowo-gumowe wulkanizowane siarką = Polyurethane-rubber composites vulcanization of sulphur
PublicationW artykule przedsawiono wyniki badań statycznych i dynamicznych właściwości mechanicznych oraz analizę mikroskopową nowych kompozytowych materiałów poliuretanowo-gumowych wulkanizowanych siarką otrzymanych z kauczuków uretanowych wulkanizowanych siarką i recyklatu gumowego w postaci granulatu o wielkości ziarna do 1 mm uzyskanego z poużytkowych opon samochodowych. Osnowy poluretanowe napełniano recyklatem w ilościach od 10 do 80%...
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Produkcja współczesnych rur ciśnieniowych o dużych średnicach
PublicationRury wielkośrednicowe do przesyłu cieczy pod ciśnieniem. Szczegóły rozwiązań rur stalowych i rur z tworzyw twardoplastycznych i miękkoplastycznych o średnicach ponad 1200 mm. Szczególne problemy rur HDPE, wytrzymałość, ciśnienia, grubość ścian, transport do odbiorcy. Charakterystyczne "tratwy" z odcinków rurowych o długości do ponad 1 km. Przykład rozwiązań w zakładzie produkcyjnym Stathelle na wybrzeżu Fiordu Oslo.
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Investigations of welded joints of dissimilar heat resistant steels.
PublicationPrzeprowadzono badania metalograficzne połączeń spawanych różnorodnych stali żarowytrzymałych rur o przekroju 31,8x7,1 mm ze stali 10H2M z blachą ze stali 20H23N18. Badania makro- i mikrostruktury złączy spawanych wykazały, że istotnym czynnikiem wpływającym na właściwości mechaniczne złącza jest obecność wad takich jak pory lub wtrącenia żużla. Te nieciągłości w materiale powodują koncentrację naprężeń i powstawanie mikropęknięć.
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Wpływ drzewienia elektrycznego na prądy polaryzacyjne i depolaryzacyjne w izolacji polietylenowej
PublicationW pracy przedstawiono wyniki badań prądów polaryzacyjnych i depolaryzacyjnych układu ostrze - płyta uziemiona w polietylenie sieciowanym (XLPE). Zastosowano próbki XLPE z igłą o promieniu ostrza 5 mm symulującą typowe niejednorodności występujące w procesie wytwarzania izolacji kablowej. Analizowano przebieg prądów polaryzacyjnych i depolaryzacyjnych dla różnego stopnia starzenia próbek izolacji, charakteryzującego się inną długością...
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Teoretyczna analiza procesu walcowania trójwarstwowego pasma AlMg-Al-Cu, Theoretical analysis of rolling process of composite plate AlMg-Al-Cu
PublicationPrzedstawiono symulacje komputerowe walcowania blach AlMg-Al-Cu łączonych wybuchowo. Symulacje przeprowadzono dla procesu walcowania w walcarce o średnicy walców D=150 mm z indywidualnym napędem walców roboczych. W ramach badań numerycznych określono wpływ nierówności odkształcenia warstw tworzących pasmo oraz nieliniowy rozkład predkości warstw blachy w kotlinie walcowniczej asymetrycznie walcowanej blachy trójwarstwowej AlMg-Al-Cu.
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Pt-rich intermetallic APt8P2 (A = Ca and La)
PublicationThe combination of experimental and theoretical investigation of two new Pt-rich intermetallic compounds: APt8P2 (A = Ca and La) is presented, including solid-state synthesis, crystal structure determination, physical properties characterization and chemical bonding analysis. APt8P2 was obtained through the high-temperature pellet synthesis. According to both single crystal and powder X-ray diffraction results, APt8P2 crystallize...
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Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography
PublicationThis paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement...
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A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
PublicationIn this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations...
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New uranium(vi) and isothiouronium complexes: synthesis, crystal structure, spectroscopic characterization and a DFT study
PublicationThe crystal structures of S,S′-2,5-dimethylbenzene-1,4-diylbis(methylisothiouronium) diacetate (1_ac), S,S′-2,5-dimethylbenzene-1,4-diylbis(methylisothiouronium) dichloride (1_Cl), 1_U complex, S,S′-naphthalene-1,4-diylbis(methylisothiouronium) dichloride (2_Cl), and 2_U complex were determined for the first time. The supramolecular structures of the compounds obtained are mainly based on hydrogen bonding and ionic interactions...
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Axial capacity of steel built-up battened columns
PublicationThis paper deals with the numerical investigation aimed to study the axial capacity of pin-ended steel built-up columns. Three methods of calculating forces in chords and batten, taking into account the material and geometric imperfections specified in the Eurocode 3 are considered. The aim of this study was to compare different methods allowing the calculation of the column load capacity and determine a simpler and faster method...
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An application of multi-agent system for ship’s power systems design
PublicationDesign process of transport ship power system consists of structure (topology) and component elements selection. Compliance with the requirements for static components does not guarantee optimal dynamic characteristics of entire power system. Design steps are difficult to formalize and as a consequence to this reason expert and multi-agent systems are used for solving selected design issues. In the paper distributed multi-agent...
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The model of end-to-end call setup time calculation for Session Initiation Protocol
PublicationEnd-to-end call setup delay is one of the most important grade of service (GoS) parameters for VoIP networks with Session Initiation Protocol (SIP). A typical subscriber wants to have a connection established as soon as possible. From the operator's perspective call setup time is also crucial because he needs to know how probability of successful packet transmission on SIP links is related to a call setup delay. Then he can make...
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Dissociative Electron Attachment to 5-Iodo-4-thio-2′-deoxyuridine: A Potential Radiosensitizer of Hypoxic Cells
PublicationIn the search for effective radiosensitizers for tumor cells, halogenated uracils have attracted more attention due to their large cross section for dissociation upon the attachment of low-energy electrons. In this study, we investigated dissociative electron attachment (DEA) to 5-iodo-4-thio-2'-deoxyuridine, a potential radiosensitizer using a crossed electron-molecule beam experiment coupled with quadrupole mass spectrometry....
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Potential Energy Curves of Diatomic Alkali Molecules Datasets
PublicationThe datasets described in this article contain potential energy curves for several diatomic systems. The data was obtained via high-performance computing using MOLPRO, a system of ab initio programs for advanced molecular electronic structure calculations. The datasets allow to model bond lengths, energy levels, spectra and time-evolution of molecular dimers for which the data are presented.
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Investigation of rotational state-changing collisions of C2N− ions with helium
PublicationThe cross sections for rotational inelastic collisions between atoms and a molecular anion can be very large, if the anion has a dipole moment. This makes molecular anions very efficient in cooling atomic gases. We address rotational inelastic collisions of Helium atoms with the molecular anion C2N–. Here we present preliminary calculations of the potential energy surface.
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On the effective properties of foams in the framework of the couple stress theory
PublicationIn the framework of the couple stress theory, we discuss the effective elastic properties of a metal open-cell foam. In this theory, we have the couple stress tensor, but the microrotations are fully described by displacements. To this end, we performed calculations for a representative volume element which give the matrices of elastic moduli relating stress and stress tensors with strain and microcurvature tensors.
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Badanie wytrzymałości połączeń klejonych węglowych i aluminiowych elementów zawieszenia bolidu formuły student
PublicationPodczas projektowania innowacyjnego zawieszenia, które pozwoliłoby uzyskać przewagę nad konkurencyjnymi bolidami Formuły Student, postawiono warunek, aby jak najbardziej zmniejszyć masę elementów. Używane do tej pory rurki wykonane ze stali S235 o średnicy zewnętrznej 12 mm i grubości 2 mm oraz w miejscach bardziej obciążonych o średnicy zewnętrznej 14 mm i grubości 2 mm cechowały się znaczną masą. Ich głównym zadaniem jest połączenie...