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Evaluation of granulability and absorbtivity of biomass in agglomeration mixture

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Journal of Central South University 2017年第10期24卷 2260-2265页

作者： Hudák Jozef Lesko jaroslav Semanová Zuzana Frohlichová Mária Findorák Róbert Legemza jaroslav Institute of Metallurgy Faculty of MetallurgyTechnical University of KosiceKosice04200Slovakia

The granulability and absorbtivity of sawdust and coke breeze were *** properties are important within the preparation of agglomeration *** have a significant impact on plynodynamic batch *** of materials to wet is a fundamental condition of granulability of *** and water absorption of wood with liquids is generally significantly affected by their chemical *** important factors affecting the wetting process are undoubtedly the wood moisture content,the value of the surface tension of liquid media and their chemical *** increasing moisture content of wood,the time to equilibrium *** of water absorption and granulability of sawdust was conducted to seek their possible use as a partial replacement of coke dust in the production of the *** have been realized with alder,oak and pine sawdust and reference material-coke *** materials were divided to four classes of granularity:supplied material,1-2 mm,0.5-1 mm and less than 0.5 *** different liquid media were used:water 16°C,water 60°C,soapy water,lime milk and surfactant.

关键词： agglomeration biomass coke breeze granulability absorbtivity

Classification of Spectra of Emission Line Stars Using Machine Learning Techniques

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International Journal of Automation and computing 2014年第3期11卷 265-273页

作者： Pavla Bromová Petr koda jaroslav Vázn Faculty of Information Technology Brno University of Technology Astronomical Institute of the Academy of Sciences of the Czech Republic

Advances in the technology of astronomical spectra acquisition have resulted in an enormous amount of data available in world-wide telescope archives. It is no longer feasible to analyze them using classical approaches, so a new astronomical discipline,astroinformatics, has emerged. We describe the initial experiments in the investigation of spectral line profiles of emission line stars using machine learning with attempt to automatically identify Be and B[e] stars spectra in large archives and classify their types in an automatic manner. Due to the size of spectra collections, the dimension reduction techniques based on wavelet transformation are studied as well. The result clearly justifies that machine learning is able to distinguish different shapes of line profiles even after drastic dimension reduction.

关键词： Be star stellar spectrum feature extraction dimension reduction discrete wavelet transform classification support vector machines(SVM) clustering.

Effect of storage conditions on long-term stability of Ag nanoparticles formed via green synthesis

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International Journal of Minerals,Metallurgy and Materials 2017年第10期24卷 1177-1182页

作者： Oksana Velgosova Elena Cizmarova jaroslav Málek Jana Kavulicova Institute of Materials Faculty of Metallurgy Technical University of Kosice Letna 9 042 00 Kosice Slovakia Department of Materials Engineering Faculty of Mechanical Engineering Czech Technical University in Prague Karlovo nám. 13 121 32 Prague 2 Czech Republic Institute of Metallurgy Faculty of Metallurgy Technical University of Kosice Letna 9 042 00 Kosice Slovakia

Spherical Ag nanoparticles(AgNPs) with a diameter of 20 nm or smaller were biologically synthesized using algae Parachlorella kessleri. The effect of storage conditions on the long-term stability of AgNPs was investigated. UV/Vis spectrophotometry, transmission electron microscopy, and dynamic light scattering measurements revealed that the long-term stability of AgNPs was influenced by light and temperature conditions. The most significant loss of stability was observed for the AgNPs stored in daylight at room temperature. The AgNPs stored under these conditions began to lose their stability after approximately 30 d; after 100 d, a substantial amount of agglomerated particles settled to the bottom of the Erlenmeyer flask. The AgNPs stored in the dark at room temperature exhibited better long-term stability. Weak particle agglomeration began at approximately the 100 th day. The AgNPs stored in the dark at about 5℃ exhibited the best long-term stability; the AgNPs stored under such conditions remained spherical, with a narrow size distribution, and stable(no agglomeration) even after 6 months. Zeta-potential measurements confirmed better dispersity and stability of AgNPs stored under these conditions.

关键词： silver nanoparticles stability storage conditions green synthesis Parachlorella kessleri

Social networks of reintroduced Przewalski's horses in the Great Gobi B Strictly Protected Area (Mongolia)

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Current Zoology 2024年第2期70卷 182-194页

作者： Anna Bernatkova Ganbaatar Oyunsaikhan jaroslav Simek Martina Komarkova Francisco Ceacero Faculty of Tropical AgriSciences Czech University of Life Sciences PragueCzech Republic Great Gobi B Strictly Protected Area Takhin TalMongolia Zoo Praha U Trojského zamku 120/3PragueCzech Republic

Analyzing social networks is a powerful tool for understanding the ecology of social *** most studies focus on the role of each group member,few compare groups with different *** current population of Przewalski's horses Equus ferus przewalskii at the Great Gobi B Strictly Protected Area(Mongolia)includes groups of wild-born and captive-bred individuals with different experiences with the area(acclimatizing,long-term reintroduced,and wild-born),therefore serving as an ideal natural behavioral *** filmed 11 groups for 141.5 hours in summer 2018(July),late spring 2019(May,June),and autumn 2019(September,October).Affiliative and agonistic interactions were recorded,and social networks were *** tested the influence of origin,experience,season,sex,age,relative time belonging to the group,relat-edness,and dominance rank on different network indices at the individual and group *** found that groups with greater experience in the area are generally better connected than members of the newly formed ***,these strong networks were created by wild-born individuals with very low interaction *** the contrary,inexperienced groups composed of captive-bred individuals displayed many inter actions but created weak social *** results show a trend of behavioral transition from acclimatizing through long-term reintroduced to wild-born groups,supporting that the newly formed groups of released Przewalski's horses need time to display the typical social behavior patterns of wild-born ***-term monitoring of released Przewalski's horses is recommended to promote the success of this reintroduction program.

关键词： Przewalski's horses reintroduction social behavior soft-release.

Structural and optical properties of nanostructured copper sulfide semiconductor synthesized in an industrial mill

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Frontiers of Chemical Science and Engineering 2019年第1期13卷 164-170页

作者： Marcela Achimovicova Erika Dutkova Erika Tothova Zdenka Bujnakova jaroslav Briancin Satoshi Kitazono Institute of Mineral and Waste Processing Waste Disposal and Geomechanics Clausthal University of Technology Clausthal 38678 Germany Institute of Geotechnics Slovak Academy of Sciences Kosice 04001 Slovakia Nakase Refinery Nihon Seiko Co. Ltd. Yabu-shi Hyogo 667-1111 Japan

Chalcogenide nanostructured semiconductor, copper sulfide (CuS) was prepared from copper and sulfur powders in stoichiometric ratio by a simple, fast, and convenient one-step mechanochemical synthesis after 40 min of milling in an industrial eccentric vibratory mill. The kinetics of the mechanochemical synthesis and the influence of the physical properties of two Cu powder precursor types on the kinetics were studied. The crystal structure, physical properties, and morphology of the product were characterized by X-ray diffraction (XRD), the specific surface area measurements, particle size distribution and scanning electron microscopy. The XRD analysis confirmed the hexagonal crystal structure of the product-CuS (covellite) with the average size of the crystallites 11 nm. The scanning electron microscopy analysis has revealed that the agglomerated grains have a plate-like structure composed of CuS nanoparticles. The thermal analysis was performed to investigate the thermal stability of the mechanochemically synthesized CuS. The optical properties were studied using UV-Vis and photoluminescence spectroscopy. The determined optical band gap energy 1.80 eV responds to the value of the bulk CuS, because of agglomerated nanoparticles. In addition, a mechanism of CuS mechanochemical reaction was proposed, and the verification of CuS commercial production was performed.

关键词： copper sulfide industrial mechanochemical synthesis thermal analysis optical properties

Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet

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Journal of Thermal Science 2016年第2期25卷 138-144页

作者： Martin Luxa Jaromír Príhoda David Simurda Petr Straka jaroslav Synác Institute of Thermomechanics AS CR v.v.i. Dolejskova 1402/5 18200 Prague Czech Republic Aerospace Research and Test Establishment Plc Beranovych 130 19905 Prague Czech Republic Doosan Skoda Power Co. Ltd. Tylova 1/57 30128 Pilsen Czech Republic

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.

关键词： long turbine rotor blade supersonic tip section optical methods transition modelling CFD

Augmented Node Placement Model in t-WSN Through Multiobjective Approach

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Computers, Materials & Continua 2021年第12期69卷 3629-3644页

作者： Kalaipriyan Thirugnansambandam Debnath Bhattacharyya jaroslav Frnda Dinesh Kumar Anguraj Jan Nedoma School of Computer Science and Engineering VIT UniversityChennai CampusTamilnaduIndia Department of Computer Science and Engineering Koneru Lakshmaiah Education FoundationVaddeswaramGunturIndia Department of Quantitative Methods and Economic Informatics Faculty of Operation and Economics of Transport and CommunicationsUniversity of Zilina01026 ZilinaSlovakia Department of Telecommunications Faculty of Electrical Engineering and Computer ScienceVSB-Technical University of Ostrava70833 Ostrava-PorubaCzech Republic

In Wireless Sensor Network(WSN),coverage and connectivity are the vital challenges in the target-based *** linear objective is to find the positions to cover the complete target nodes and connectivity between each sensor for data forwarding towards the base station given a grid with target points and a potential sensor placement *** this paper,a multiobjective problem on target-based WSN(t-WSN)is derived,which minimizes the number of deployed nodes,and maximizes the cost of coverage and sensing *** Evolutionary-based Non-Dominated Sorting Genetic Algorithm-II(NSGA-II)is incorporated to tackle this multiobjective problem *** problems are intended to solve different objectives of a problem ***-inspired algorithms address the NP-hard problem most effectively in recent *** NSGA-II,the Non-Dominated sorting preserves the better solution in different objectives simultaneously using dominance *** the diversity maintenance phase,density estimation and crowd comparison are the two components that balance the exploration and exploitation phase of the *** of NSGA-II on this multiobjective problem is evaluated in terms of performance indicators Overall Non-dominated Vector Generation(ONGV)and Spacing(SP).The simulation results show the proposed method performs outperforms the existing algorithms in different aspects of the model.

关键词： Focused wireless sensor network m-coverage k-connectivity problem non-dominated sorting NSGA-II

Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

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Journal of Thermal Science 2018年第2期27卷 95-102页

作者： Jindrich Hala Martin Luxa David Simurda marek Bobcik Ondrej Novak Bartolomej Rudas jaroslav Synac Institute of Thermomechanics of The Czech Academy of Sciences Prague Czech Republic Doosan Skoda Power Ltd Pilsen Czech Republic Faculty of Mechanical Engineering University of West Bohemia Pilsen Czech Republic

This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements （optical and pneumatic）.

关键词： steam turbine blade cascade root section

The effect of climate factors on the size of forest wildfires(case study:Prague-East district,Czech Republic)

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Journal of Forestry Research 2022年第4期33卷 1291-1300页

作者： Zohreh Mohammadi Peter Lohmander Jan Kašpar Roman Berčák jaroslav Holuša Robert Marušák Faculty of Forestry and Wood Sciences Czech University of Life Sciences PragueKamýcká12916500 Praha-SuchdolCzech Republic Optimal Solutions in Cooperation with Linnaeus University UmeaSweden

This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest *** linear regression was used in combination with nonlinear variable transformations to determine relevant nonlinear forest wildfire size *** from the Prague-East District of the Czech Republic was used for model *** burned forest area was hypothesized as a function of water vapor pressure,air temperature and wind *** speed was added to enhance predictions of the size of forest wildfires,and further improvements to the utility of prediction methods were added to the regression *** results show that if the air temperature increases,it may contain less water and the fuel will become *** size of the burned area then *** the relative humidity in the air increases and the wind speed decreases,the size of the burned area is *** model suggests that changes in the climate factors caused by ongoing climate change could cause significant changes in the size of wildfire in forests.

关键词： Climatic variables Burned forest area Climate change Multiple linear regression