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Search results for: dc corona discharge, ehd flow, flow measurement, pi
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Low energy differential elastic electron scattering from trichloromethane
PublicationExperimental differential cross sections for low energy electron scattering from trichloromethane is measured utilizing a crossed electron-molecular beam experiment via the relative flow method, for the incident electron energies in the range of E = 0.5 eV-30 eV and the scattering angles in the range of θ = 10◦ − 130◦ .
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Microjet technology as a perspective intensification method for high performance heat exchangers
PublicationIn the paper two oryginal designs of compact heat exchangers with intensification effect produced by microjets are presented. The technology of microjets manufacturing is an "inhouse" patented design. The idea of such heat exchanger is shown together with the flow and thermal characteristics of the prototypes. The results of performer measurements are satisfactory and encourage for further research of the original designs.
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Stormwater and snowmelt runoff storage control and flash flood hazard forecasting in the urbanized coastal basin.
PublicationCity of Gdańsk is located in a coastal region where changing climatic conditions increase the frequency of extreme weather events. Developing urbanization affects the hydrology of natural basins by simplification of the drainage system and reduction of infiltration and base flow. Consequently greater runoff rates flow into storm water collection systems, reservoirs and surrounding water bodies. Not only infrastructures of urban...
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Losses and energy efficiency of drive motors and systems
PublicationLosses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Improvement of the thrust bearing calculation considering the convectional heating within the space between the pads
PublicationA modern thrust bearing calculation tool should consider not only the oil film between pad and rotating collar but also the space between the pads. The oil flow in the space has a significant influence on the oil film inlet temperature, the convectional cooling of pad and collar and should be included in the bearing calculation methods. The authors use a tool developed at Clausthal University of Technology in cooperation with the...
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Assessment of the ice jam potential on regulated rivers and reservoirs with the use of numerical model results
PublicationThis study presents an attempt at estimating the jam potential on rivers with significant anthropogenic intervention in the course or flow characteristics of the river. The DynaRiCE model was used for forecasting both the place and time of an ice jam occurrence. In this modified method, two ice parameters are subjected to analysis, namely the relative ice-to-water velocity (vi/vw),and the ice thickness to single floe thickness...
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Flicker Noise in Resistive Gas Sensors—Measurement Setups and Applications for Enhanced Gas Sensing
PublicationWe discuss the implementation challenges of gas sensing systems based on low-frequency noise measurements on chemoresistive sensors. Resistance fluctuations in various gas sensing materials, in a frequency range typically up to a few kHz, can enhance gas sensing by considering its intensity and the slope of power spectral density. The issues of low-frequency noise measurements in resistive gas sensors, specifically in two-dimensional...
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Recognition of Hand Drawn Flowcharts
PublicationIn this paper the problem of hand drawn flowcharts recognition is presented. There are described two attitudes to this problem: on-line and off-line. A concept of FCE, a system for recognizing and understanding of freehand drawn on-line flow charts on desktop computer and mobile devices is presented. The first experiments with the FCE system and the planes for future are also described.
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Microwave Characterization of Dielectric Sheets in a Plano-Concave Fabry-Perot Open Resonator
PublicationDespite its long history, a double-concave (DC) Fabry-Perot open resonator (FPOR) has recently gained popularity in the characterization of dielectrics in the 20–110 GHz range, mainly due to such novel accomplishments as full automation of the measurement process and the development of even ore accurate and computationally efficient electromagnetic model. However, it has been discovered that such a DC resonator suffers from unwanted...
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The Influence of Water and Mineral Oil on Pressure Losses in Hydraulic Motor
PublicationIn this paper, pressure losses in hydraulic motor supplied with water and mineral oil (two liquids that have significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a hydraulic satellite motor that is dedicated to working with different liquids, including water. The methodology of measuring the pressure drop in internal channels of this motor is also...
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Prediction of coking dynamics for wet coal charge
PublicationA one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal...
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Natural radioactivity of solid and liquid phases from shale oil and gas prospection in Pomerania
PublicationIonizing radiation intensity data and estimation of equivalent absorbed dose from solid and liquid samples from prospection of shale gas and oil at selected sites in Pomerania are presented. Naturally occurring radioactive materials (NORM) are associated with geological formations or fluids and can be enhanced during oil and gas production. They appear in e.g. drilling cuttings, flow back water, produced water, scale and sludge....
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Optical emission spectroscopy of plasma generated by a waveguide-supplied microwave plasma source operated at 915MHz
PublicationIn this paper we present the results of an optical emission spectroscopic study of an atmospheric pressure microwave (915 MHz) nitrogen and nitrogen with carbon dioxide (1%) plasma at high working gas flow rate. This study was aimed at determining rotational Trot and vibrational Tvib temperatures of N+2 ions and N2, CN molecules. The plasma was generated in a waveguide-supplied cavity-resonant type microwave plasma source. All...
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Performance Evaluation of Selected Parallel Object Detection and Tracking Algorithms on an Embedded GPU Platform
PublicationPerformance evaluation of selected complex video processing algorithms, implemented on a parallel, embedded GPU platform Tegra X1, is presented. Three algorithms were chosen for evaluation: a GMM-based object detection algorithm, a particle filter tracking algorithm and an optical flow based algorithm devoted to people counting in a crowd flow. The choice of these algorithms was based on their computational complexity and parallel...
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Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublicationA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
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Pozwól płynąć swojemu produktowi
PublicationAutor: Joanna Czerska Autorki i współautorki rozdziałów: Anna Sarbiewska:15.2 OEE dla maszynMarzena Leszczyk-Kabacińska:18. 5S i wizualizacja pracy w gnieździe19. Standaryzacja pracy w gnieździe22. Program ciągłego doskonalenia Recenzja naukowa:Prof. zw. ds. hab. Bogdan Nogalski, Uniwerystet Gdański, 27.02.2010 --- Jeśli poszukujesz...
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VSC converters control for offshore wind farms HVDC grid connection
PublicationThe paper proposes a voltage sourced converter (VSC) new control method. A well-known in the electric power systems correlation between voltage angle and active power and correlation between voltage and reactive power is used instead of feedforward control. This allows for a fast and almost independent control of active and reactive power flow.
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Influence of mesh density on 2D viscous flutter in a turbomachinery cascade
PublicationIn this study numerical simulations of 2D viscous flutter were performed and compared with available experimental results for various mesh densities and flow parameters. Calculations were carried out for the bending oscillations of an Eleventh Standard Configuration cascade. ANSYS CFX code was used for the SST, SA and k-ω turbulence model calculations.
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Simulation of Residence Time Distribution and Mixing in Reactors with Recirculation Using 2D Approach
PublicationIn this paper, we propose a 2D approach in order to create a mathematical model for the determination of the residence time distribution for a flow reactor with recirculation. Apart from characterizing the functional residence time distribution, this model can help improve the operation of the reactor at the design stage. The mathematical model was validated by comparison with experiments carried out in a hydraulic laboratory.
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Broadening the scope of measurement and analysis of vibrations of an organ pipe employing intensity probe, simulations, and highspeed camera
PublicationThis paper shows an integrated approach to measure, analyze, and model phenomena occurring in an organ pipe driven by pressurized air. The aim of this paper is two-fold, i.e., to measure the pressure signal and the intensity field around the mouth by means of an intensity probe and to visualize and observe the motion of the air jet, which represents the excitation mechanism of the system. This is realized through two techniques,...
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High Frequency Harmonics Emission in Smart Grids
PublicationPulse-width modulated rectifiers are nowadays commonly used for AC to DC power conversion. PWM rectification technology is very effective and allows for bidirectional power flow with the possibility of power factor improvement and low-order harmonic emission limitation. Unfortunately, employed PWM boost topology results with generation of input current harmonic distortions in a frequency range tightly correlated to modulation frequency....
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Investigations on the immunosuppressive activity of derivatives of mycophenolic acid in immature dendritic cell
PublicationThe main activity of mycophenolic acid (MPA) and its analogs is the inhibition of proliferation of T cells. Here, we hypothesized that MPA and its conjugates inhibits also the activity of antigen-presenting cells (APC) including dendritic cells (DCs). We tested the effect of novel amino acid derivatives of MPA and conjugates of MPA with acridines/acridones on DCs by flow cytometry, ELISA and MLR assay. Both acridines/acridone derivatives...
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Low Frequency Conducted Emissions of Grid Connected Static Converters
PublicationPulse-width modulated rectifiers are nowadays commonly used for AC to DC power conversion. PWM rectification technology is very effective and allows for bidirectional power flow with the possibility of power factor improvement and low-order harmonic emission limitation. Unfortunately, employed PWM boost topology results with generation of input current harmonic distortions in a frequency range tightly correlated to modulation frequency....
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Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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Wpływ liczby mieszkańców na obliczenia ilości ścieków w projektowaniu kanalizacji sanitarnej
PublicationZmiana sposobu rozliczania zużycia wody, promocja wodooszczędnych technologii oraz uszczelnienie kanałów wyraźnie wpłynęły na ilość odprowadzanych do kanalizacji ścieków. Obecnie stwierdzić można, że opracowania z lat 70-tych XX wieku podają zawyżone wskaźniki odpływu ścieków, skutkiem czego są problemy eksploatacyjne. Bez wątpienia, prawidłowe zaprojektowanie kanalizacji sanitarnej to zadanie trudne, wymagające między innymi prawidłowego...
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Modeling of low calorific gas burning in a deficient oxygen environment and high-temperature oxidizer
PublicationThe experimental research will be performed using the experimental facility with a combustion chamber. The oxygen concentration in combustion oxidizers will be varied from 21% by volume (normal) air to 2%. The test combustion chamber will be fed with propane or methane as the reference fuel, then with low calorific fuels as test gases obtained by mixing various combustible components, e.g. H2, CH4, CO, and neutral gases, e.g. N2,...
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Partial Admission Stages of High Efficiency for a Microturbine
PublicationThe paper presents the results of a design analysis of a microturbine for a cogeneration micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3 kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attentionwas paid...
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Numerical Simulations and Tracer Studies as a Tool to Support Water Circulation Modeling in Breeding Reservoirs
PublicationThe article presents a proposal of a method for computer-aided design and analysis of breeding reservoirs in zoos and aquariums. The method applied involves the use of computer simulations of water circulation in breeding pools. A mathematical model of a pool was developed, and a tracer study was carried out. A simplified model of two-dimensional flow in the form of a biharmonic equation for the stream function (converted into...
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Multiobjective Aerodynamic Optimization by Variable-Fidelity Models and Response Surface Surrogates
PublicationA computationally efficient procedure for multiobjective design optimization with variable-fidelity models and response surface surrogates is presented. The proposed approach uses the multiobjective evolutionary algorithm that works with a fast surrogate model, obtained with kriging interpolation of the low-fidelity model data enhanced by space-mapping correction exploiting a few high-fidelity training points. The initial Pareto...
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The role of SSVF and SSHF beds in concentrated wastewater treatment, design recommendation
PublicationThe return flows of reject water from sewage sludge dewatering alter the activated sludge process ina conventional WWTP and increase TN concentration in the final effluent from WWTP. The objectiveof the investigation carried out was to consider the application of multistage treatment wetland(MTW) for the treatment of reject water from sewage sludge dewatering in a centrifuge (RWC). Thispaper aims to present the design and performance...
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On Accuracy Modeling of Gas Turbine Cycles by the In-house COM-GAS Code
PublicationIn this paper, a comparison of accuracy modeling of gas turbine cycles between the basic (classical) model and the in-house COM-GAS code has been presented. The basic model uses a semi-perfect gas and well known projecting assumption. On the other hand, the computational flow mechanics (CFM) basis on a real gas by using thermodynamic tables. The thermodynamic analysis of thermal cycles, simply gas cycle GT8C and gas turbine cycle...
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Partial Admission Stages of High Efficiency for a Microturbine
PublicationThe paper presents the results of a design analysis of a micro-turbine for a co-generation micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attention was...
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The novel sterilization device: the prototype testing
PublicationCurrently, there are numerous methods that can be used to neutralize pathogens (i.e., devices, tools, or protective clothing), but the sterilizing agent must be selected so that it does not damage or change the properties of the material to which it is applied. Dry sterilization with hydrogen peroxide gas (VHP) in combination with UV-C radiation is well described and effective method of sterilization. This paper presents the design,...
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Magnetoacoustic heating in a quasi-isentropic magnetic gas
PublicationThe nonlinear heating of a plasma which associates with the transfer of energy of magnetoacoustic waves into that of the entropy mode, is analytically studied. A plasma is uniform and motionless at equilibrium. Perturbations in a plasma are described by a system of ideal magnetohydrodynamic equations. The equilibrium straight magnetic strength and the wave vector form a constant angle which varies from 0 to π/2. There exist four...
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Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublicationJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
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A device for measuring heat flux on a rocket skin surface
PublicationA novel method for measuring heat flux on a surface is presented. It is an extensive upgrade of currently known heat flux sensors used mostly in civil engineering. As the thermal environment of launchers, especially sounding rocket can have an enormous negative effect on payload, careful considerations have to be taken in the process of preparing insulation. Usually, thermal data provided by the launch vehicle manufacturer is limited...
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Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
PublicationAmong renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system...
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Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation
PublicationOne of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW...
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Compact broadband multi-way 1:6 power divider
PublicationThis paper introduces a design flow of a microstrip multi-way 1:6 power divider incorporating photonic bandgap (PBG) structures. Themethod proposed has enabled the achievement of considerable miniaturization (15%) together with transmission characteristics enhancement(141% bandwidth). Measured results show significant similarity to theoretical characteristics, which proves the attractiveness of presented design methodology.
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Estimation of wind pressure acting on the new palm house in Gdansk
PublicationThis paper deals with the problem of numerical simulations of wind loads acting on a Palm House with complex geometry. Flow simulations with aid of computational fluid dynamics procedures have been performed to check if the pressure distributions for the structure are greater than those calculated using the standard design codes with assumption that the Palm House horizontal cross sections are described by smooth cylinders.
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Metoda diagnostyki cieplno-przepływowej turbin parowych wykorzystująca elementy algorytmów genetycznych
PublicationRozprawa doktorska poświęcona jest opisowi budowania metody diagnostyki cieplno-przepływowej z wykorzystaniem elementów algorytmów genetycznych. Do tworzenia założeń i algorytmów metody posłużono się przykładem funkcjonowania bloku elektrowni kondensacyjnej ze szczególnym uwzględnieniem układu łopatkowego turbiny parowej. Celem pracy jest zbudowanie metody diagnostyki cieplno-przepływowej. Zadaniem metody jest przeprowadzenie procesu...
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Measurements of Thermal Conductivity of LWC Cement Composites Using Simplified Laboratory Scale Method
PublicationThe implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial...
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Removal of cyclohexane and ethanol from air in biotrickling filters inoculated with Candida albicans and Candida subhashii
PublicationThis paper presents investigations on the removal of cyclohexane and ethanol from air in polyurethane- -packed biotrickling filters, inoculated with Candida albicans and Candida subhashii fungal species. Results on process performance together with flow cytometry analyses of the biofilm formed over packing elements are presented and discussed. The results indicate that the presence of ethanol enhances the removal efficiency of cyclohexane...
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The influence of microjet array area ratio on heat transfer in the compact heat exchanger
PublicationThe paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger....
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Methods of Determining Pressure Drop in Internal Channels of a Hydraulic Motor
PublicationIn this paper, new methods for determining the pressure drop in internal channels of a hydraulic motor are proposed and described. Mathematical models of pressure losses in internal channels have also been described. Experimental tests of the satellite motor were carried out according to one of the proposed methods. The tests were carried out for two liquids, i.e., water and mineral oil. Experimental studies have shown that at...
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The impact of internal and international migration on regional convergence in Poland
PublicationAccording to neoclassical theory, migration is expected to speed up the convergence process between countries (Barro, Sala-i-Martin 2004). The flow of labour from low-wage regions to high-wage regions should equalise payrolls. However, the impact of migration on convergence rates is unclear when the labour flow is heterogeneous. Moreover, the movement of labour towards wealthier areas depresses the demand for goods, services and...
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New conjugates of tuftsin and muramyl dipeptide as stimulators of human monocytes-derived dendritic cells
PublicationMuramyl dipeptide (MDP) and tuftsin are known biologically active compound displaying a significant influence on various cell populations of innate immune response. MDP, as a fragment of bacterial cell wall, stimulates not only macrophages and monocytes, but also dendritic cells. In contrast, little is known about tuftsin influence on these cells. Therefore it seemed vital to access whether tuftsin or its derivatives conjugated...
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Sound intensity distribution around organ pipe
PublicationThe aim of the paper was to compare acoustic field around the open and stopped organ pipes. The wooden organ pipe was located in the anechoic chamber and activated with a constant air flow, produced by an external air-compressor. Thus, long-term steady state response was possible to obtain. Multichannel acoustic vector sensor was used to measure the sound intensity distribution of radiated acoustic energy. Measurements have been...
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Methodology of generation of CFD meshes and 4D shape reconstruction of coronary arteries from patient-specific dynamic CT
PublicationDue to the difficulties in retrieving both the time‑dependent shapes of the vessels and the generation of numerical meshes for such cases, most of the simulations of blood flow in the cardiac arteries use static geometry. The article describes a methodology for generating a sequence of time‑dependent 3D shapes based on images of different resolutions and qualities acquired from ECG‑gated coronary artery CT angiography. The precision...