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Search results for: high-speed bearing tilting pad bearing polymeric bearings microturbine low-boiling liquid
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Weldability of high strength steel in underwater environment
PublicationThe article describes the problems with weldability of high-strength steels in the aquatic environment. The tendency of steel S355J2G3 and S500M to form cold cracks when welded in wet welding conditions has been experimentally evaluated. It was found that the tested steels have a high propensity to cracking. An experiment has been proposed and tested to evaluate the usefulness of the tempering bead technique as a method of improving...
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Simple and low-cost wireless voting system
PublicationThis paper presents the concept of a simple and low-cost wireless voting system working on the 868 MHz frequency band. Described system is dedicated to general shareholders assemblies but it can be easily adapted for other applications. The main advantage is its simplicity and mobility as it consists solely of three components - voting modules, base station and a PC application from which the whole system is managed. This architecture...
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Simple and low-cost wireless voting system
PublicationThis paper presents the concept of a simple and low-cost wireless voting system working in the 868 MHz frequency band. The described system is dedicated to general shareholders assemblies but it can be easily adapted for other applications. The main advantage is its simplicity and mobility as it consists solely of three components - voting modules, a base station and a PC application from which the whole system is mamaged. This...
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Fatigue resistance investigation of the mb46 plain bearings under conditions of dynamic loadings
PublicationOdporność materiału łożyskowego MB46 na pęknięcia zmęczeniowe badano na stanowisku SMOK, w którym generowane jest zmienne jednokierunkowe obciążenie badanego łożyska. Materiał łożyskowy MB46 składa sie z warstwy brązu CuPb22Sn 3 spiekanego na taśmie stalowej, stanowiącej podłoże. Na warstwę brązu nałożona jest galwanicznie cienka warstwa stopu SnCu6 stanowiąca powłokę. Każde z badanych łożysk poddawane było 20-godzinnemu testowi...
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Diagnostic model of compression-ignition engine slide bearings for controlling the changes of their state
PublicationW artykule przedstawiono koncepcję umożliwiającą sterowanie procesami zmian stanów eksploatacyjnych silnika na podstawie modelu diagnostycznego łożysk ślizgowych. Jako model łożyska ślizgowego przyjęty został topologiczny model diagnostyczny, pozwalający na pełne i dokładne wykorzystanie oleju smarowego jako jednego z nośników informacji o stanie technicznym łożyska. Przedstawiona została przykładowa interpretacja stanów eksploatacyjnych...
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Concept for interpretation and assessment of slide bearings operation in Diesel enfines in probabilistic approach
PublicationW artykule zaproponowano interpretację wartościującą działania, które (podobnie jak przedstawione w mechanice klasycznej działania Hamiltona i Maupertiusa oraz działanie wynikające ze zmiany pędu ciała) jest rozpatrywane jako wielkość fizyczna o jednostce miary zwanej''dżulosekundą''. Przedstawiono propozycję ilościowej interpretacji działania dowolnego poprzecznego łożyska ślizgowego, w którym zachodzą oddziaływania energetyczne...
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Klocki samopompujące w łożyskach hydrodynamicznych = Self-pumping pads in the hydrodynamic bearings
PublicationWe współpracy z firmą ALSTOM HYDRO (Szwajcaria), zespół Katedry Konstrukcji i Eksploatacji Maszyn Politechniki Gdańskiej przeprowadził symulacje przepływowe kilku rozwiązań konstrukcyjnych mających na celu zwiększenie niezawodności turbin wodnych. W artykule opisano jedno z takich rozwiązań - tak zwane łożysko z klockami samopompującymi. Głównym celem jest uzyskanie przepływu oleju w układzie smarowania łożyska hydrodynamicznego...
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Environmentally friedly propeller shaft support with the use of water lubricated foil bearings
PublicationW pracy przedstawiono podsumowanie prowadzonych badań w celu opracowania oryginalnej metodyki projektowania oraz technologii wykonania pierwszego w świecie łożyska foliowego smarowanego wodą. Zaprezentowano koncepcje nowego łożyska foliowego poprzecznego oraz opisano opracowany algorytm obliczeniowy wykorzystany do predykcji jego charakterystyk. W rezultacie prowadzonych prac opracowano i przebadano doświadczalnie na stanowisku...
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Study of pH and temperature effect on lipophilicity of catechol-containing antioxidants by reversed phase liquid chromatography
PublicationLipophilicity of selected antioxidant phytochemicals, including flavonoids, phenolic acids and xanthonoids, was determined by reversed phase high performance liquid chromatography with UV detection (RP-HPLC-UV). The analyses run at different temperature and pH conditions in isocratic mode suggested that lipophilicity as distribution coefficient (logD) between aqueous and organic phase decreases with increasing temperature. For...
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Studies on the utilization of post-distillation liquid from Solvay process to carbon dioxide capture and storage
PublicationIn this work, a method of precipitated calcium carbonate production from the post-distillation liquid created in the Solvay process and waste carbon dioxide was proposed and investigated. Precipitation was carried out in a model solution of calcium chloride containing ammonia at various molar ratios in relation to Ca2+ ions, while gaseous carbon dioxide was supplied to the reactor as a pure gas or as a mixture with air. It was...
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Theoretical investigation of the structural insights of the interactions of γ-Fe2O3 nanoparticle with (EMIM TFSI) ionic liquid
PublicationOne of the possible applications of ionic liquids is to produce electricity from heat. The iron oxide nanoparticle is a potent electrical particle, which is expected to improve the heat’s efficiency to electricity conversion, however, it is prone to aggregation and sedimentation, which hamper its application. One of the methods to enhance the nanoparticle’s solubility and electrical properties is the use of a stabilizing component...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Low-coherence sensors with nanolayers for biomedical sensing
PublicationIn this paper, we describe the fiber optic low-coherence sensors using thin film. We investigated their metrological parameters. Presented sensors were made with the use of standard telecommunication single mode optical fiber (SMF28). Different materials were applied to obtain thick layers, such as boron doped diamond, silver and gold. The thickness of layers used in the experiments ranged from 100 nm to 300 nm. Measurements were...
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Troubleshooting of the determination of bisphenol A at ultra-trace levels by liquid chromatography and tandem mass spectrometry
PublicationDetermination of trace amounts of bisphenol A (BPA) may cause problems mainly related to the presence of BPA in solvents (even in LC-MS grade), laboratory vessels, and plastic equipment used for sample preparation. Variable and sometimes significant amounts of BPA present in the background cause problems in obtaining good repeatability of measurements at the ultra-trace levels. Such observations (i.e., poor repeatability of results)...
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Unusual Influence of Fluorinated Anions on the Stretching Vibrations of Liquid Water
PublicationInfrared (IR) spectroscopy is a commonly used and invaluable tool in the studies of solvation phenomena in aqueous solutions. Concurrently, ab initio molecular dynamics (AIMD) simulations deliver the solvation shell picture at a molecular detail level and allow for a consistent decomposition of the theoretical IR spectrum into underlying spatial correlations. Here, we demonstrate how the novel spectral decomposition techniques...
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Development of Safirinium dyes for new applications: fluorescent staining of bacteria, human kidney cells, and the horny layer of the epidermis
PublicationLow-molecular synthetic fluorophores are convenient tools in bioimaging applications. Several derivatives of Safirinium dyes as well as their reactive N-hydroxysuccinimide (NHS) esters bearing diverse substituents were synthesized and evaluated experimentally in terms of their lipophilicity by means of reverse-phase and immobilized artificial membrane high-performance liquid chromatography. Subsequently, the selected compounds...
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High-throughput Evaluation of Lipophilicity and Acidity by New Gradient HPLC Methods
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High Performance Control of AC Drives with Matlab/ Simulink
PublicationExplore this indispensable update to a popular graduate text on electric drive techniques and the latest converters used in industry. The Second Edition of High Performance Control of AC Drives with Matlab®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges...
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Sensitive determination of isoprostanes in exhaled breath condensate samples with use of liquid chromatography-tandem mass spectrometry
PublicationOxidative stress is the hallmark of various inflammatory lung diseases. Increased concentrations of reactive oxygen species in the lungs are reflected by elevated concentrations of oxidative stress markers in the breath, airways, lung tissue and blood. The aim of this work was to develop a method for the fast measurement of F2 isoprostanes in exhaled breath condensate (EBC) samples using equipment which is nowadays available and...
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Low cost microwave X-band generator
PublicationA low cost microwave X-band generator for educational purposes was designed and built. Its simple construction and user's interface makes it suitable for a student laboratory.The generator is based on a single frequency conversion concept. It uses a digitally tunable PLL chip for intermediate frequency generation and an active frequency multiplier for frequency conversion. The generator covers 9,7 - 11 GHz part of the X frequency...
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Numerical analysis of crack propagation in silicone nitride
PublicationThe properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation...
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Low-strain sensor based on the flexible boron-doped diamond-polymer structures
PublicationA free-standing high boron-doped diamond nanosheet (BDDNS) has been fabricated for the development of a flexible BDDNS strain senor. High boron-doped diamond was initially grown on a tantalum substrate in a microwave plasma-assisted chemical vapor deposition method, and was then transferred to a Kapton polymer substrate to fabricate the flexible BDDNS/Kapton device. Before performing the transfer process, the thin BDDNS’s morphology...
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ANN for human pose estimation in low resolution depth images
PublicationThe paper presents an approach to localize human body joints in 3D coordinates based on a single low resolution depth image. First a framework to generate a database of 80k realistic depth images from a 3D body model is described. Then data preprocessing and normalization procedure, and DNN and MLP artificial neural networks architectures and training are presented. The robustness against camera distance and image noise is analysed....
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Uncertainty analysis of measuring system for instantaneous power research
PublicationThe paper presents a metrological analysis of the measurement system used for diagnosis of induction motor bearings, based on the analysis of the instantaneous power. This system was implemented as a set of devices with dedicated software installed on a PC. A number of measurements for uncertainty estimation was carried out. The results of the measurements are presented in the paper. The results of the aforementioned analysis helped...
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Periodic Properties of 1D FE Discrete Models in High Frequency Dynamics
PublicationFinite element discrete models of various engineering 1D structures may be considered as structures of certain periodic characteristics. The source of this periodicity comes from the discontinuity of stress/strain field between the elements. This behaviour remains unnoticeable, when low frequency dynamics of these structures is investigated. At high frequency regimes, however, its influence may be strong enough to dominate calculated...
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Response of a New Low-Coherence Fabry-Perot Sensor to Hematocrit Levels in Human Blood
PublicationIn this paper, a low-coherence Fabry-Perot sensor with a spectrally measured signal processing response to the refractive index of liquids is presented. Optical fiber sensors are potentially capable of continuous measuring hematocrit levels in blood. Low-coherence Fabry-Perot interferometric sensors offer a robust solution, where information about the measurand is encoded in the full spectrum of light reflected from the sensing...
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Enhanced method of DS-CDMA low level singnals detection
PublicationThe following article comprises three main parts. The first one generally describes two methods of low level signals detection which are in the interest of this study. The signal spectrum averaging technique is shown as well as the method exploiting averaged spectrum of the signal raised to the power of 2n (nN). Additionally, this section briefly presents proposed enhancements and modifications of these two solutions, which allow...
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Epoxy/Ionic Liquid-Modified Mica Nanocomposites: Network Formation–Network Degradation Correlation
PublicationWe synthesized pristine mica (Mica) and N-octadecyl-N’-octadecyl imidazolium iodide (IM) modified mica (Mica-IM), characterized it, and applied it at 0.1–5.0 wt.% loading to prepare epoxy nanocomposites. Dynamic differential scanning calorimetry (DSC) was carried out for the analysis of the cure potential and kinetics of epoxy/Mica and epoxy/Mica-IM curing reaction with amine curing agents at low loading of 0.1 wt.% to avoid particle...
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International Strategy as the Facilitator of the Speed, Scope, and Scale of Firms’ Internationalization
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Prediction of the Results of Chatter Vibration Surveillance by the Spindle Speed Control
PublicationDrgania samowzbudne typu chatter są istotnym zjawiskiem występującym podczas obróbki szybkościowej (HSM) z użyciem smukłych narzędzi. Zastosowanie optymlano-liniowego sterowania prędkością obrotową narzędzia w celu nadzorowania drgań pozwoliło zredukowac te drgania. W artykule przedstawiono sposób predykcji rezultatów nadzorowania z użyciem dwóch różnch modeli dynamiki skrawania zastosowanych w symulacjach komputerowych.
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Chatter vibration surveillance by the optimal-linear spindle speed control
PublicationArtykuł dotyczy drgań samowzbudnych typu chatter podczas obróbki szybkościwowej frezami kulistymi. Opisano w nim niestacjonarny model procesu skrawania oraz przeprowadzono analizy dynamiki układu z opóźniającym sprzężeniem zwrotnym. W celu zredukowania drgań zaproponowano zmiany prędkości obrotowej wrzeciona. Przedstawiono także procedurę nadzorowaia drgań z wykorzystaniem opisanej metody. Dla wybranych przypadków, w artykule przedstawiono...
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Model of speed-varing rotor for mechatronic systems analysis and design
PublicationW artykule przedstawiono sposób modelowania złożonych układów mechatronicznych w oparciu o metodę grafów wiązań. Celem zilustrowania metody posłużono się przykładem liczbowym, w którym rozważano wirnik obracający się ze zmienną prędkością kątową. Prezentowana metodyka doskonale nadaje się do modelowania układów o zróżnicowanej naturze fizycznej. Otrzymany model ma charakter obiektu o pewnej liczbie wejść i wyjść, który można w...
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Speed observer system for advanced sensorless control of induction motor.
PublicationW pracy przedstawiono obserwator prędkości silnika asynchronicznego zastosowany w układzie sterowania ze zmiennymi multiskalarnymi oraz regulatorem predykcyjnym prądu. Zawarto wyniki badań symulacyjnych i eksperymentalnych.
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Vibration surveillance in modern milling machines by the spindle speed control.
PublicationPraca poświęcona jest nadzorowaniu drgań wirujących narzędzi w nowo-czesnych frezarkach. Polega ono na zastosowaniu sterowania programo-wego w układach niestacjonarnych. Dotyczy to zamkniętych układów obra-biarek, kiedy to istotną rolę odgrywają drgania samowzbudne typu chat-ter. Sygnałem sterującym jest chwilowa zmiana prędkości obrotowej. Rozważano frezowanie czołowe smukłym frezem trzpieniowym na pionowym centrum frezarskim....
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Traffic Speed Deflectometer for Network-Level Pavement Management in Tennessee
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The programmed spindle speed control to reduce the level of the chatter vibration
PublicationOpracowano strategię nadzorowania drgań ''chatter'' za pomocą programowego sterowania prędkością obrotową wrzeciona obrabiarki. Skuteczność tej strate-gii jest obserwowana w czasie całego procesu obróbkowego. Ponadto zastosowa-nie jej wymaga poniesienia tylko niewielkich nakładów finansowych, gdyż nie są konieczne zmiany w układzie napędowym i sterowania CNC.
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The spindle speed optimal control as a mean of chatter vibration surveillance
PublicationNowa metoda nadzorowania drgań wirujących narzędzi w nowoczesnych frezarkach polega na wykorzystaniu sterowania optymalnego w układach niestacjonarnych przy energetycznym wskaźniku jakości. W rezultacie, sygnałem sterującym jest chwilowa zmiana prędkości obrotowej wrzeciona. Rozważano frezowanie czołowe smukłym frezem trzpieniowym. Wyniki symulacji komputerowych potwierdziły praktyczne uzasadnienie proponowanej metody. Drgania...
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The influence of fuel type on heat balance of medium-speed engine
PublicationW artykule zaprezentowano analizę wpływu rodzaju zastosowanego paliwa na bilans cieplny silników średnioobrotowych stosowanych w energetyce stacjonarnej. Przedmiotem analizy są silniki ZS i ZI zasilane gazem ziemnym oraz silniki ZS zasilane olejem napędowym. Dodatkowo analizę uzupełniono o wyniki obliczeń wykonanych dla silników dwupaliwowych, tzn. silników, w których zapłon mieszanki paliwowo gazowej realizowany jest przez pilotażowy...
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Signal Processing in the Investigation of Two-phase Liquid-gas Flow by Gamma-ray Absorption
Publicationn this paper, the use of the gamma-absorption method applied in the investigation of the two-phase liquid-gas flow in the pipeline is described. An example of its application to the air transported by water in a horizontal pipeline is evaluated. In the measurements, Am-241 radioactive sources and probes with Nal (Tl) scintillation crystals have been used. The signals from the radiometric set were used to determine the velocity...
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Low-power device simulator for micro-energy measurement methods testing
PublicationThe paper presents low-power device simulator designed for testing of micro-energy measurement methods. Such kind methods can be used for evaluation of power systems based on Energy Harvesting. The device allows to set the current consumption characteristic over the time, thus making possible playing the role of different types of low-power devices e.g. simulating sensor network node.
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Critical evaluation of recent achievements in low power glow discharge generated at atmospheric pressure between a flowing liquid cathode and a metallic anode for element analysis by optical emission spectrometry
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Use of AMI Meters in the Process of Low Voltage Grid Optimization
PublicationThis is a report of a project involving, inter alia, low voltage grid performance optimization with data from AMI meters . The study was supported with a European UPGRID grant, and executed by a consortium of companies from seven European countries, including Poland .
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A comparison of muscle activity of the dominant and non-dominant side of the body during low versus high loaded bench press exercise performed to muscular failure
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Experimental study on steel columns subjected to impact load under earthquake conditions
PublicationEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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Inverse surrogate modeling for low-cost geometry scaling of microwave and antenna structures
PublicationPurpose–The purpose of this paper is to investigate strategies for expedited dimension scaling ofelectromagnetic (EM)-simulated microwave and antenna structures, exploiting the concept of variable-fidelity inverse surrogate modeling.Design/methodology/approach–A fast inverse surrogate modeling technique is described fordimension scaling of microwave and antenna structures. The model is established using referencedesigns obtained...
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Low-Reflection Subgridding
PublicationArtykuł przedstawia technikę umieszczania makromodeli w trójwymiarowej siatce dyskretyzacji metody różnic skończonych. Umożliwia ona łączenie obszarów siatki o różnym kroku dyskretyzacji. Zastosowana prosta interpolacja liniowa wraz z kolokacją pól sąsiadujących ze sobą podobszarów prowadzi do uzyskania małego współczynnika odbicia od obszaru z gęstą siatką.
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Assessment of Tensile Strength Reserve of Asphalt Mixtures at Low Temperatures
PublicationDuring winter conditions, low-temperature cracks develop at the surface of the asphalt pavement when tensile thermal stress induced in the asphalt layer during cooling equals and exceeds the tensile strength of the material. The paper presents the results of tensile strength reserve assessment of asphalt mixtures with neat and SBS-polymer modified bitumen application. The tensile strength reservewas calculated as difference between...
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Experimental test of nonclassicality with arbitrarily low detection efficiency
PublicationWe theoretically introduce and experimentally demonstrate the realization of a nonclassicality test that allows for arbitrarily low detection efficiency without invoking an extra assumption of independence of the devices. Our test and its implementation is set in a prepare-and-measure scenario with an upper limit on the classical communication capacity of the channel through which the systems are communicated. The essence for our...
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Optimization of liquid chromatographic separation of pharmaceuticals within green analytical chemistry framework
PublicationThe contribution is aimed at the development of methodology that allows to consider green analytical chemistry criteria during optimization of liquid chromatographic separation with design of experiment. The objectives of the optimization are maximization of peak areas of five non-steroid anti-inflammatory drugs, maximization of resolution between peaks, with simultaneous shortening of chromatographic separation time and minimization...
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Rapid Characterization of the Human Breast Milk Lipidome Using a Solid-Phase Microextraction and Liquid Chromatography-Mass Spectrometry-Based Approach.
PublicationHuman breast milk (HBM) is a biofluid consisting of various biomolecules such as proteins, lipids, carbohydrates, minerals and bioactive substances. Due to its unique and complex composition, HBM provides not only nutritional components required for the growth of the infant, but also additional protection against infections. Global insight into the composition of HBM is crucial to understanding the health benefits infants receive...