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Search results for: VACUUM TECHNOLOGIES
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THE PROPERTIES OF NANOSILVER – DOPED NANOHYDROXYAPATITE COATING ON THE Ti13Zr13Nb ALLOY
PublicationThe aim of this research was to study the properties of nanohydroxyapatite (nanoHAp) and nanohydroxyapatite, doped with nanosilver (nanoHAp/nanoAg), coatings obtained by an electrophoretic deposition process. The suspensions was prepared by dispersing 0.1 g of HAp nanopowder for nanoHAp coatings and 0.1 g of nanoHAp and 0.025 g nanoAg for nanoHAp/nanoAg coatings. The deposition was carried out for 1 min at 50 V voltage followed...
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Photofragmentation of tetrahydrofuran molecules in the vacuum-ultraviolet region via superexcited states studied by fluorescence spectroscopy
PublicationPhotofragmentation of tetrahydrofuran molecules in the vacuum-ultraviolet region, producing excited atomic and molecular fragments, has been studied over the energy range 14-68 eV using photon-induced fluorescence spectroscopy. Excited hydrogen atoms H(n), n = 3-11, have been detected by observation of the Hα to Hı lines of the Balmer series. The diatomic CH(A2Δ), CH(B2Σ-) and C2(d3Πg) fragments, which are excited to low vibrational...
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Valence and Ionic Lowest-Lying Electronic States of Isobutyl Formate Studied by High-Resolution Vacuum Ultraviolet Photoabsorption, Photoelectron Spectroscopy, and Ab Initio Calculations
PublicationThe highest resolution vacuum ultraviolet photoabsorption spectrum of isobutyl formate, C5H10O2, yet reported is presented over the energy range 4.5−10.7 eV (275.5−118.0 nm) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator...
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Tuning the work function of graphite nanoparticles via edge termination
PublicationGraphite nanoparticles are important in energy materials applications such as lithium-ion batteries (LIBs), supercapacitors and as catalyst supports. Tuning the work function of the nanoparticles allows local control of lithiation behaviour in LIBs, and the potential of zero charge of electrocatalysts and supercapacitors. Using large scale density functional theory (DFT) calculations, we find that the surface termination of multilayer...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results
PublicationThe edge criteria for magnetic-fluid seals durability research are critical for the seal'stechnological usefulness. The magnetic fluid seal technology in water is much moredifficult technological problem in comparison to gas or vacuum environment. There isalways problem with immediate contact between magnetic fluid and the environmentaluninspected liquids. In the paper are presented ways of experiments definitions carried outwith...
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Theory versus experiment for vacuum Rabi oscillations in lossy cavities
PublicationThe 1996 experiment by Brune et al. [Phys. Rev. Lett. 76, 1800 (1996)] on vacuum Rabi oscillation is analyzed by means of alternative models of atom-reservoir interaction. Agreement with experimental Rabi oscillation data can be obtained if one defines jump operators in the dressed-state basis and takes into account thermal fluctuations between dressed states belonging to the same manifold. Such low-frequency transitions could...
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O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission
PublicationOxygen 1s excitation and ionization processes in the CO2 molecule have been studied with dispersed and non-dispersed fluorescence spectroscopy as well as with the vacuum ultraviolet (VUV) photon-photoion coincidence technique. The intensity of the neutral O emission line at 845 nm shows particular sensitivity to core-to-Rydberg excitations and core-valence double excitations, while shape resonances are suppressed. In contrast,...
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Preparation and Characterization of Diamond-like Carbon Coatings for Biomedical Applications—A Review
PublicationDiamond-like carbon (DLC) films are generally used in biomedical applications, mainly because of their tribological and chemical properties that prevent the release of substrate ions, extend the life cycle of the material, and promote cell growth. The unique properties of the coating depend on the ratio of the sp3/sp2 phases, where the sp2 phase provides coatings with a low coefficient of friction and good electrical conductivity,...
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Evaluation of the Impact of Storage Conditions on the Biogenic Amines Profile in Opened Wine Bottles
PublicationA survey of biogenic amine (BA) profiles in opened wine bottles has been established to monitor the level of biogenic amines (BAs) in opened bottles against time and other conditions. Bottles of red and white wine were submitted to different temperatures, stopper type (screw cap, cork), and use of vacuum devices. A total of six wines made from a variety of grapes were obtained from vineyards from regions across Poland. Dispersive...
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The potential of imogolite nanotubes as (co-)photocatalysts: a linear-scaling density functional theory study
PublicationWe report a linear-scaling density functional theory (DFT) study of the structure, wall-polarization absolute band-alignment and optical absorption of several, recently synthesized, open-ended imogolite (Imo) nanotubes (NTs), namely single-walled (SW) aluminosilicate (AlSi), SW aluminogermanate (AlGe), SW methylated aluminosilicate (AlSi-Me), and double-walled (DW) AlGe NTs. Simulations with three different semi-local and dispersion-corrected...
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Electromodulation of monomer and excimer phosphorescence in vacuum-evaporated films of platinum (II) complexes of 1,3-di(2-pyridyl)benzenes
PublicationElectric field-modulated photoluminescence (EML) measurements are presented for vacuum-evaporated films of cyclometallated Pt (II) complexes of 1,3-di(2-pyridyl) benzenes used as triplet emitters in organic light-emitting diodes (OLEDs). The excimer phosphorescence is quenched by the external electric field of 2.5 MV/cm up to 25% but the same effect on monomer phosphorescence is one order of magnitude smaller. The higher quenching...
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Applications of the discrete green's function in the finite-difference time-domain method
PublicationIn this paper, applications of the discrete Green's function (DGF) in the three-dimensional (3-D) finite-difference time-domain (FDTD) method are presented. The FDTD method on disjoint domains was developed employing DGF to couple the subdomains as well as to compute the electromagnetic field outside these subdomains. Hence, source and scatterer are simulated in separate subdomains and updating of vacuum cells, being of little...
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Sano-Tachiya-Noolandi-Hong, Onsager and Braun models vs Monte Carlo simulation of charge photogeneration in organic solids
PublicationThe Sano-Tachiya-Noolandi-Hong (STNH), Onsager, and Braun models as well as Monte Carlo (MC) simulations of charge recombination/separation have been applied for the first time to reproduce the results of the electromodulated photoluminescence measurements in vacuum-evaporated films of fluorescent materials commonly used in optoelectronic devices. The values of the electron-hole pair final recombination speed in the monomer emitters:...
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Synchrotron radiation photoemission spectroscopy of the oxygen modified CrCl3 surface
PublicationWe investigate the experimentally challenging CrCl3 surface by photon energy dependent photoemission (PE). The core and valence electrons after cleavage of a single crystal, either in a ultrahigh vacuum (UHV) or in air, are studied by keeping the samples at 150 1C, aiming at confirming the atomic composition with respect to the expected bulk atomic structure. A common spectroscopic denominator revealed by data is the presence of...
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Preparation and characterization of TiO2 nanostructures for catalytic CO2 photoconversion
PublicationThe titanium dioxide target (99.7%) of 1 cm in dia was ablated in vacuum by laser pulses(6 ns) at 266 nm and at repetition rate of 10 Hz. During deposition the laser fluence between 1 and 3.5 J/cm2 and the O2 pressure from the range of 10-2 - 1 Pa were applied. The thin TiO2 films were deposited on glass substrate (1 × 1 cm2) heated up to 500 °C. The chemical composition of the film and samples produced by annealing were investigated...
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Absolute Photoabsorption Cross-Sections of Methanol for Terrestrial and Astrophysical Relevance
PublicationWe investigate the methanol absorption spectrum in the range 5.5–10.8 eV to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol electronic-state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with state-of-the-art quantum chemical calculation methods. The VUV spectrum reveals several new features...
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Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
PublicationLarge deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation...
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The Impact of Different Drying Methods on the Metabolomic and Lipidomic Profiles of Arthrospira platensis
PublicationDrying is an inseparable part of industrial microalgae production. In this work, the impacts of eight different drying methods on the metabolome and lipidome of Arthrospira platensis were investigated. The studied drying methods were freeze drying (FD), sun drying (SD), air drying at 40 and 75 °C (AD′ and AD″), infrared drying at 40 and 75 °C (IRD′ and IRD″), and vacuum drying at 40 and 75 °C (VD′ and VD″). Results gathered by...
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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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Compact High Efficiency and Zero-Emission Gas-Fired Power Plant with Oxy-Combustion and Carbon Capture
PublicationReduction of greenhouse gases emissions is a key challenge for the power generation industry, requiring the implementation of new designs and methods of electricity generation. This article presents a design solution for a novel thermodynamic cycle with two new devices—namely, a wet combustion chamber and a spray-ejector condenser. In the proposed cycle, high temperature occurs in the combustion chamber because of fuel combustion...
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A new type of (TiZrNbTaHf)N/MoN nanocomposite coating: Microstructure and properties depending on energy of incident ions
PublicationA novel (TiZrNbTaHf)N/MoN nanocomposite coatings, which consist of the nitride of the high-entropy alloy and the binary nitride, were synthesized by vacuum-arc deposition at various substrate biases. The elemental composition, chemical bonding state, phase structure, microstructure and mechanical properties of the coatings were studied by high-resolution experimental methods: SIMS, GDMS, XPS, XRD, HR-TEM and nano-indentation. It...
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Electromodulation of photoluminescence in vacuum-evaporated films of bathocuproine
PublicationElectric field-modulated photoluminescence (EML) was measured in vacuum-evaporated films of bathocuproine (BCP), electron-transporting material commonly used in organic light-emitting diodes (OLEDs). The external electric field of 106 V/cm strength decreases long-wavelength photoluminescence (PL) up to 10% but the same effect on short-wavelength PL is above one order of magnitude smaller. The distinctive difference between the...
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AIMS5.0 Artificial Intelligence in Manufacturing leading to Sustainability and Industry5.0
ProjectsProject realized in Department of Microwave and Antenna Engineering
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AIMS5.0 Artificial Intelligence in Manufacturing leading to Sustainability and Industry5.0
ProjectsProject realized in Department of Microwave and Antenna Engineering
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Density functional theory calculations on entire proteins for free energies of binding: Application to a model polar binding site
PublicationIn drug optimization calculations, the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method can be used to compute free energies of binding of ligands to proteins. The method involves the evaluation of the energy of configurations in an implicit solvent model. One source of errors is the force field used, which can potentially lead to large errors due to the restrictions in accuracy imposed by its empirical nature....
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An electric ring thruster as auxiliary manoeuvring propulsion system for watercraft - construction analysis
PublicationThe reported project aimed at examining properties and purposefulness of use of modern electromagneticbearings for a screw propeller in a prototype version of a synchronous ring motor with rare earths magnets.Bearings of this type generate electromagnetic forces which keep the rotor in a state of levitation. Therotating machine with magnetic bearings can work in any environment which reveals diamagnetic properties(air, vacuum,...
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DL_MG: A Parallel Multigrid Poisson and Poisson–Boltzmann Solver for Electronic Structure Calculations in Vacuum and Solution
PublicationThe solution of the Poisson equation is a crucial step in electronic structure calculations, yielding the electrostatic potential -- a key component of the quantum mechanical Hamiltonian. In recent decades, theoretical advances and increases in computer performance have made it possible to simulate the electronic structure of extended systems in complex environments. This requires the solution of more complicated variants of the...
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The electronic excited states of dichloromethane in the 5.8-10.8 eV energy range investigated by experimental and theoretical methods
PublicationWe present a comprehensive experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of dichloromethane, CH 2 Cl 2 , with absolute cross sections determined for the full 5.8–10.8 eV energy-range. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-of-motion coupled cluster method, restricted to the single and double excitations level (EOM-CCSD), and...
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The New Test Procedure for Group-Type Composition of Base Oils of Lubricating Oils, Especially Emitted into the Environment
PublicationMineral base oil, a product of multistep fine refining of the relevant fractions from vacuum distillation of crude oil, is a main component of so-called mineral lubricating oils containing aliphatic and alicyclic substituted aromatic hydrocarbons, i.e., derivatives of benzene and biphenyl. Mineral lubricating oil is composed mostly of mineral base oil and a low amount of enriching additives, most often products of advanced organic...
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Electrical Simulations of the SIS100 Superconducting Dipole and Quadrupole Circuits: Transients, Earthing and Failure Modes
PublicationThe 100 Tm superconducting synchrotron SIS100 is the main accelerator of the international Facility for Antiproton and Ion Research (FAIR) currently under advanced construction in Darmstadt, Germany. The SIS100 dipole circuit which creates the magnetic field required to bend the beam, consists of 108 dipoles distributed over six arc sections of the ring. The magnetic field for the beam focusing is generated by three individual...
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Investigation of Microbes in the Stratosphere – Stardust Project
PublicationThe stratospheric microbiota has been investigated many times using the methods of classical microbiology. In this research a few modern methods, including NGS sequencing and multiple displacement amplification of DNA, were in use. The analysis of metagenome helped to determine the content of various species of bacteria in the sample collected in the stratosphere by a hydrogen-filled balloon holding...
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Intramolecular Proton Transfer in the Radical Anion of Cytidine Monophosphate Sheds Light on the Sensitivities of Dry vs Wet DNA to Electron Attachment-Induced Damage
PublicationSingle-strand breaks (SSBs) induced via electron attachment were previously observed in dry DNA under ultrahigh vacuum (UHV), while hydrated electrons were found not able to induce this DNA damage in an aqueous solution. To explain these findings, crossed electron-molecular beam (CEMB) and anion photoelectron spectroscopy (aPES) experiments coupled to density functional theory (DFT) modeling were used to demonstrate the fundamental...
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Quenching effects in organic electroluminescence
PublicationWe examine various electronic processes that underlie the quenching of the emission from highly efficient phosphorescent and electrophosphorescent organic solid-state molecular systems. As an example, we study the luminescent efficiencies from the phosphorescent iridium (III) complex, fac tris (2-phenylpyridine) iridium [(Ir (ppy)3] doped into a diamine derivative doped polycarbonate hole-transporting matrix and in the form...
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A Multi Rig Screening Test for Thin Ceramic Coatings in Bio - Tribological Applications
PublicationA method is presented for the comparative testing of wear resistance of ceramic coatings made from materials potentially feasible in tribo - medical applications, mainly orthopaedic implants made from ceramics coated metals for low cost, long life and low wear particle emission into the body. The method was devised as the main tool for use in research and is comprised of flat on flat and ball on flat surface (sliding) tests. Seven...
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Two-body dissociation of isoxazole following double photoionization – an experimental PEPIPICO and theoretical DFT and MP2 study
PublicationThe dissociative double photoionization of isoxazole molecules has been investigated experimentally and theoretically. The experiment has been carried out in the 27.5–36 eV photon energy range using vacuum ultraviolet (VUV) synchrotron radiation excitation combined with ion time-of-flight (TOF) spectrometry and photoelectron–photoion–photoion coincidence (PEPIPICO) technique. Five wellresolved two-body dissociation channels have...
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Li nucleation on the graphite anode under potential control in Li-ion batteries
PublicationApplication of Li-ion batteries in electric vehicles requires improved safety, increased lifetime and high charging rates. One of the most commonly used intercalation anode material for Li-ion batteries, graphite, is vulnerable to Li nucleation, a side reaction which competes with the intercalation process and leads to loss of reversible capacity of the battery, ageing and short-circuits. In this study, we deploy a combined grand...
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A study of a compact high-efficiency zero-emission power plant with oxy-fuel combustion
PublicationThis paper discusses the application of global trends in gas cycles technology using oxy-fuel combustion. This is followed by a demonstration of a design solution for a new cycle with two enhanced energy-converting devices, namely a wet combustion chamber and a spray-ejector condenser. The proposed gas and steam cycle unit is contained within a single turbine, whose benefits combine those offered by gas turbines (high inlet temperatures)...