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Particle electrification in an apparatus with a draft tube operating in a fast circulating dilute spout-fluid bed regime

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Particuology 2019年第1期17卷 146-153页

作者： wojciech Ludwig Wroclaw University of Science and Technology Faculty of Chemistry. Department of Chemical EngineeringNorwida 4/650-373 WroclawPoland

The intensity of the electrostatic charge accumulated during the flow of Cellets^■ particles in a modified Wurster apparatus is investigated in terms of the bed mass, and the initial moisture and velocity of the spouting gas. Particle electrification is proportional to the increase in the velocity of the spouting gas, which is connected with a higher velocity of the cores and the strength of their impact on the walls of the device. The presence of moisture in the bed facilitates electrification, but does not affect circulation, since moisture simultaneously lowers the bed resistance and reduces the relaxation time of particles, leading to rapid discharging if brought into contact with the conducting elements of the apparatus. Therefore, with regard to classic dry-powder coating, the velocity of the spouting gas should be minimized to ensure good circulation, with the particle moisture held at the maximum level admissible for a given product. The investigations show that a unique construction of the apparatus, which brings about an intense natural electrification of the cores, makes it suitable for the electrostatic dry-coating process by means of a high-voltage feeder with the controlled charging of coating powder in the spray nozzle.

关键词： Electrification Electrostatic charge Spout-fluid bed Wurster apparatus

Wave Propagation in A Converging Channel of Arbitrary Configuration

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China Ocean Engineering 2015年第5期29卷 771-782页

作者： wojciech SULISZ Institute of Hydroengineering Polish Academy of Sciences

A numerical solution was derived to determine wave field in a converging channel bounded by rubble-mound jetties. The solution was achieved by applying boundary element method. The model was applied to analyze the effect of channel convergence, the cross-section of the jetties and their physical and damping properties on wave field in the channel. The study reveals numerous non-intuitive results specific for jetted and convergent channels. The analysis shows that wave reflection is usually low and is of secondary practical importance. Wave transmission strongly depends on the channel geometry and transmitted waves may be higher than incident waves, despite reflection and damping processes. Moreover, wave transmission depends on physical and damping properties of rubble jetties and the results show that wave transmission may increase with the increasing damping properties of jetties, which is a non-intuitive feature of wave fields in jetted channels. The analysis reveals several novel results of practical importance. It is shown that the rubble-mound jetties should be constructed from the material of high porosity, which ensures low transmission. More attention should be devoted to hydraulic properties of porous materials. It is recommended to use the material of moderate damping properties. The material of high damping properties often increases the wave transmission. It is possible, by a selection of rubble-mound material, to obtain lower transmission level for steep waves than for waves of moderate steepness. A series of laboratory experiments were conducted in the wave flume to verify the theoretical results. The comparisons show that theoretical results are in fairly good agreement with experimental data.

关键词： jetted converging channel wave propagation wave damping numerical modeling

AUGMENTED REALITY SYSTEM FOR AIDING ENGINEERING DESIGN PROCESS OF MACHINERY SYSTEMS

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Journal of Systems Science and Systems Engineering 2011年第3期20卷 294-309页

作者： Marcin JANUSZKA wojciech MOCZULSKI Department of Fundamentals of Machinery Design Silesian University of TechnologyKonarskiego 18A44-100 GliwicePoland

The paper presents the application of augmented reality for aiding product design and development of machinery systems. Augmented reality technology integrates an interactive computer-generated word with an interactive real word in such a way that they appear as one environment. AR technology can enhance a user＇s perception of the real world with information that is not actually part of the scene but is relevant to the user＇s present activity. Presented in the AR system is a mode for changing views of data - especially 3D models - allowing the user to understand the prospective machinery system in a more comprehensive way, thus making the design process more efficient than the one supported by conventional present-day CAD systems. The presented prototype system contains an expert system integrated with AR system and allows the delivering of knowledge to the designer about successive steps of the design process of a mobile robot and practical solutions of realized constructional problems. An approach concerning AR enables the system user to analyze and verify solutions （represented as 3D models） relative to real scenes/objects. This approach is advantageous because the real environment around us often provides a vast amount of information that is difficult to duplicate in a computer. In some cases, the application of an AR system could be an optimal way to verify developed products.

关键词： Augmented reality human-computer interface CAD design for customer satisfaction computer-aided decision making

The Impact of Bed Temperature on Heat Transfer Characteristic between Fluidized Bed and Vertical Rifled Tubes

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Journal of Thermal Science 2016年第5期25卷 476-483页

作者： Artur Blaszczuk wojciech Nowak Czestochowa University of Technology Institute of Advanced Energy Technologies Dabrowskiego 73 AGH University Science and Technology Faculty of Energy and Fuels Czarnowiejska 30

In the present work,the heat transfer study focuses on assessment of the impact of bed temperature on the local heat transfer characteristic between a fluidized bed and vertical rifled tubes(38mm-O.D.) in a commercial circulating fluidized bed(CFB) *** transfer behavior in a 1296t/h supercritical CFB furnace has been analyzed for Geldart B particle with Sauter mean diameter of 0.219 and 0.246 *** heat transfer experiments were conducted for the active heat transfer surface in the form of membrane tube with a longitudinal fin at the tube crest under the normal operating conditions of CFB boiler.A heat transfer analysis of CFB boiler with detailed consideration of the bed-to-wall heat transfer coefficient and the contribution of heat transfer mechanisms inside furnace chamber were investigated using mechanistic heat transfer model based on cluster renewal *** predicted values of heat transfer coefficient are compared with empirical correlation for CFB units in large-scale.

关键词： Cluster renewal approach heat transfer coefficient bed temperature suspension density circulating fluidized bed

Simulation of Fluid Flow in a Channel Induced by Three Types of Fin-Like Motion

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Journal of Bionic Engineering 2007年第3期4卷 165-176页

作者： wojciech Kowalczyk Antonio Delgado Institute of Fluid Mechanics University of Erlangen-NurembergCauerstr. 4D-91058 ErlangenGermany

One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles （AUV）. In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable. In the current paper an analysis of undulatory, oscillatory and combined fin-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum axe solved with the Finite Volume Method （FWM） by use of the software CFX-10.0. The undulatory and oscillatory fin movements axe modelled with an equation that is implemented within an additional subroutine and joined with the main solver. N carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations axe carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.

关键词： biofluid dynamics fro-like movement fish propulsion computational fluid dynamics

Modeling of Propagation and Transformation of Transient Nonlinear Waves on A Current

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China Ocean Engineering 2013年第5期27卷 579-592页

作者： wojciech Sulisz Maciej Paprota Institute of Hydroengineering Polish Academy of Sciencies

A novel theoretical approach is applied to predict the propagation and transformation of transient nonlinear waves on a current. The problem was solved by applying an eigenfunction expansion method and the derived semi-analytical solution was employed to study the transformation of wave profile and the evolution of wave spectrum arising from the nonlinear interactions of wave components in a wave train which may lead to the formation of very large waves. The results show that the propagation of wave trains is significantly affected by a current. A relatively small current may substantially affect wave train components and the wave train shape. This is observed for both opposing and following current. The results demonstrate that the application of the nonlinear model has a substantial effect on the shape of a wave spectrum. A train of originally linear and very narrow-banded waves changes its one-peak spectrum to a multi-peak one in a fairly short distance from an initial position. The discrepancies between the wave trains predicted by applying the linear and nonlinear models increase with the increasing wavelength and become significant in shallow water even for waves with low steepness. Laboratory experiments were conducted in a wave flume to verify theoretical results. The free-surface elevations recorded by a system of wave gauges are compared with the results provided by the nonlinear model. Additional verification was achieved by applying a Fourier analysis and comparing wave amplitude spectra obtained from theoretical results with experimental data. A reasonable agreement between theoretical results and experimental data is observed for both amplitudes and phases. The model predicts fairly well multi-peak spectra, including wave spectra with significant nonlinear wave components.

关键词： numerical modeling transient waves current boundary conditions initial conditions

Modelling of wave transmission through a pneumatic breakwater

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Journal of Hydrodynamics 2017年第2期29卷 283-292页

作者： Maciej Paprota wojciech Sulisz Institute of Hydro-Engineering of Polish Academy of Sciences GdafiskPoland

A theoretical approach is derived to study interaction of linear water waves with an air bubble curtain used as a pneumatic breakwater. Modelling of wave transmission through an aerial barrier is a complex task due to a need to cover processes associated with wave-current interaction, effects of two-phase flows, wave damping, etc.. An initial boundary-value problem is solved by applying an efficient eigenfunction expansion method and a time-stepping procedure. The derived semi-analytical solution is used to study the effect of basic parameters of the model on wave dissipative properties of the pneumatic breakwater. Results show that wave damping by the breakwater is mainly affected by an air flow rate. The increased air discharge results in higher velocities of ascending bubbles and increases aerial barrier width. This leads to a substantial reduction of transmitted wave heights, especially for waves of intermediate length and short waves. In order to verify the applicability of the presented theoretical approach, laboratory experiments are conducted in a wave flume for different wave regimes and pneumatic breakwater characteristics. The analysis of a wave trans- mission coefficient calculated numerically and measured in the laboratory confirms that the derived model can be used for a certain range of wave conditions.

关键词： Surface waves wave transmission wave-current interaction pneumatic breakwater numerical modelling

Investigation of the porous drag and permeability at the porous-fluid interface: Influence of the filtering parameters on Darcy closure

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Particuology 2023年第7期78卷 122-135页

作者： wojciech Sadowski Francesca di Mare Chair of Thermal Turbomachines and Aeroengines Department of Mechanical EngineeringRuhr University BochumUniversitatsstr.15044801Germany

The porous-fluid interface encompasses a region bridging the flow inside a porous medium and a free-flowing *** the context of volume-averaged simulations,it can be described by a set of gradually changing parameters defining the porous medium,mainly porosity and *** this paper,both the permeability and the porous-induced drag force are evaluated a-priori,by explicitly filtering a set of Particle-Resolved Simulations(PRS)of the flow in the channel partially occupied by the porous *** porous matrices are considered and the influence of the geometry and filtering parameters on the macroscopic quantities is ***,the focus is placed on the requirements for the kernel type and size to perform filtering accurately,and their impact on the distribution of permeability at the *** performance of the typically used models for the permeability is compared to the explicitly filtered ***,a new model for permeability and the drag force is introduced,taking into account the information about the fltering size and non-uniformity of the velocity *** model greatly improves the prediction of velocity at the porous-fluid interface and serves as a proof of concept that a successful porous drag model should strive to include information about both parameters.

关键词： Porous-fluid interface Explicit filtering Permeability Porous drag

Modern approaches for detection of volatile organic compounds in metabolic studies focusing on pathogenic bacteria:Current state of the art

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Journal of Pharmaceutical Analysis 2024年第4期14卷 483-505页

作者： Karolina Zuchowska wojciech Filipiak Department of Pharmacodynamics and Molecular Pharmacology Faculty of PharmacyCollegium Medicum in BydgoszczNicolaus Copernicus University in Torun85-089 BydgoszczPoland

Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific microorganisms,enabling the early diagnosis of infections and the timely implementation of tar-geted ***,complex matrices only contain trace levels of VOCs,and their constituent com-ponents can hinder determination of these ***,modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are *** this paper,we discuss bacterial VOC analysis under in vitro conditions,in animal models and disease diagnosis in humans,including techniques for offline and online analysis in clinical *** also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis,in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species in-teractions,the kinetics of VOC metabolism,and species-and drug-resistance specificity.

关键词： Volatile organic compounds Pathogenic bacteria metabolites Metabolomics Microextraction techniques Gas chromatography-mass spectrometry In vivo breath analysis In vitro model