The observation of a conductivity threshold on the electrorheological effect of p-phenylenediamine oxidized with p-benzoquinone

p-Phenylenediamine was oxidized with p-benzoquinone in the presence of 0.1-5 M methanesulfonic acid (MSA) solutions. The resulting methanesulfonate salts of 2,5-(di-p-phenylenediamine)-1,4-benzoquinone are semiconducting and the particles were further suspended in silicone oil in a weight ratio of 1 : 9 in order to create novel electrorheological fluids. Conductivity measurements using the two-point method along with dielectric spectroscopy were carried out in order to investigate their electrical and dielectric properties, including their silicone-oil suspensions. The higher the concentration of MSA was present during the synthesis, the higher the conductivity was observed. Nevertheless, a certain threshold of the ER effect has been found and a further significant increase in conductivity causes only a slight ER effect enhancement. At an electric field strength of 1.5 kV mm-1, the observed yield stresses read at the low shear rate values were 11.5 Pa, 20.3 Pa, 24.5 Pa, and 28.2 Pa for particles with conductivities 1.5 × 10-12, 8.5 × 10-11, 1.0 × 10-8, and 1.5 × 10-7 S cm-1, respectively. From dielectric spectra, it was observed that the conductivity of the particles determines the relaxation times of their silicone-oil suspensions. This journal is © The Royal Society of Chemistry.P205/12/0911, GACR, Czech Science FoundationInternal Grant Agency of Tomas Bata University [IGA/CPS/2015/007]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; Czech Science Foundation [P205/12/0911

Bidisperse magnetorheological fluids utilizing composite polypyrrole nanotubes/magnetite nanoparticles and carbonyl iron microspheres

Conductive polypyrrole nanotubes were synthesized with a two-step one-pot synthesis. During synthesis, the nanotubes were decorated with magnetite nanoparticles at different concentrations granting them magnetic properties. The characterization of the tubes revealed differences from the theoretical reactions. A bidisperse magnetorheological fluid (MRF) was prepared by mixing the composite polypyrrole nanotubes/magnetite nanoparticles with commercial carbonyl iron spherical microparticles in silicone oil. The rheological properties of the bidisperse system were studied under the presence of magnetic field at room and elevated temperature. An enhancement of the MR effect with the presence of the nanotubes was observed when compared with a standard MRF consisted only of magnetic microparticles. Due to the faster magnetic saturation of the nanotubes, this enhancement is exceptionally high at low magnetic fields. The stability of the system is studied under dynamic conditions where it is revealed that the nanotubes keep the standard particles well dispersed with the sedimentation improving by more than 50%.Internal Grant Agency of Tomas Bata University in Zlín, (IGA/CPS/2022/004, RP/CPS/2022/003); National Technical Library in Prague; Tomas Bata University in Zlin, TBU; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, MŠMT; en:MEYS, (RP/CPS/2022/007); Univerzita Tomáše Bati ve ZlíněNational Technical Library in Prague; Internal Grant Agency of Tomas Bata University in Zlin [IGA/CPS/2022/004]; project DKRVO [RP/CPS/2022/007, RP/CPS/2022/003]; Ministry of Education, Youth and Sports of the Czech Republi

Conducting and magnetic hybrid polypyrrole/nickel composites and their application in magnetorheology

Hybrid organic/inorganic conducting and magnetic composites of core–shell type have been prepared by in-situ coating of nickel microparticles with polypyrrole. Three series of syntheses have been made. In the first, pyrrole was oxidised with ammonium peroxydisulfate in water in the presence of various amounts of nickel and the composites contained up to 83 wt% of this metal. The second series used 0.1 M sulfuric acid as a reaction medium. Finally, the composites with polypyrrole nanotubes were prepared in water in the presence of structure-guiding methyl orange dye. The nanotubes have always been accompanied by the globular morphology. FTIR and Raman spectroscopies confirmed the formation of polypyrrole. The resistivity of composite powders of the order of tens to hundreds Ω cm was monitored as a function of pressure up to 10 MPa. The resistivity of composites slightly increased with increasing content of nickel. This apparent paradox is explained by the coating of nickel particles with polypyrrole, which prevents their contact and subsequent generation of metallic conducting pathways. Electrical properties were practically independent of the way of composite preparation or nickel content and were controlled by the polypyrrole phase. On the contrary, magnetic properties were determined exclusively by nickel content. The composites were used as a solid phase to prepare a magnetorheological fluid. The test showed better performance when compared with a different nickel system reported earlier.Grantová Agentura České Republiky, GA ČR, (22-25734S, 23-07244S)Czech Science Foundatio

Application of the Methodology of Communication Skills Training for Employees of Hotel Companies, Based on Immersion into the Virtual World

This paper describes a research study of communication skills training for future hotel workers in an immersive environment. The research team developed a model of the hotel reception in a virtual environment, and proposed a methodology for three-phase training. The research involved 56 testers who provided detailed feedback. To improve the communication skills of the participants, it is necessary to repeat the simulations and analyze the individual aspects of the communication in depth

Increase of effectiveness and efficiency of the business processes

Bakalářská práce se zabývá zvyšování efektivnosti a výkonnosti firemních procesů. Cílem práce je za pomoci softwarového nástroje ARIS zefektivnit výkonnost firemních procesů. V bakalářské práci je popsána část procesu u vybrané firmy a na základě rozboru jsou vyhodnoceny. V první kapitole jsou uvedeny základní pojmy, které se týkají základních pojmů firemních procesů a procesního řízení. V další kapitole je zmiňováno o Metodice ARIS a jeho použití v praxi. Dále je zde věnována pozornost problematice efektivitě a výkonnosti firemních procesů, zaměření a hledaní přínosů podnikové strategie procesů. Poslední kapitola pojednává o společnosti GMS Velkoobchod, s.r.o. kde je popsán konkrétní popis procesního modelu pomocí nástroje ARIS.The bachelor work is concerned with an increase of effectiveness and efficiency of the business processes. The objective of the work is to make the business processes more efficient with the help of the software tool ARIS. In the bachelor work there is a part of the business process in the selected company described and based on the analysis it is evaluated. In the first chapter the fundamental terms which concern the business processes and the business process control are introduced. The next chapter mentions the methodology ARIS and its use in practice. Thereinafter the attention is paid to the problems of effectiveness and efficiency of the business processes, the direction (specialization) and searching for the benefits of the business process strategy. The last chapter deals with the company GMS velkoobchod, s.r.o., it describes the particular business process model with the help of the tool ARIS.Ústav systémového inženýrství a informatikyDokončená práce s úspěšnou obhajobo

Web application for creating a cyber security profile

This Bachelor thesis describes design and implementation of optimalization program designed to find best combination of courses. The goal in this thesis was to get acquainted with European Cybersecurity Skills Framework (ECSF) in the area of cyber security, optimalization algorithms and with project Cybersecurity Skills Alliance – A New Vision for Europe (REWIRE). This thesis also includes web design and working with the database. Program is developed in the Python, PHP and Javascript programming languages. Between critical requirements of the program belongs optimality of found solution and time in which is the solution found. Program is connected with web interface, in which it is possible to search for optimal combinations based on input constraints

Internal Organizational Communication Analysis

The thesis deals with topics of internal communication with focus on its application in three particular companies. The main objective was to describe and evaluate the quality of internal communication, to analyze it and draw useful conclusions and practical recommendations to improve its efficiency. The basic concepts and specifics of information, communication, corporate culture and internal communication are presented and explained in the theoretical part, followed by an overview of the functions, goals, information flows and means of communication within the company. The assumptions of effective internal communication and related problems are accentuated. The practical part includes internal communication analysis based on a survey, qualitative interviews with managers, and company information available to the public. The thesis results in a detailed analysis of particular companies, their comparison, and specific recommendations for removal of the deficiencies and effective improvements

Analysis of Shooting Situations in Footsal

Názevpráce Analýza střeleckých situací ve futsalu. (Analysis of shooting situations at futsal.) Cíl práce Hlavním cílem této diplomové práce je zjistit a zaznamenat na základě rozboru videozáznamu a studia odborné literatury existenci opakujících se trendů v zakončení útočných akcí ve futsalu. Metoda K získání potřebných informací jsem použil metodu nepřímého pozorování videozáznamu. Zjištěné informace byly poté statisticky zpracovány. Výsledky Výsledky prezentují rozdíly při střelbě a vytváření střeleckých situací u elitních reprezentačních celků a objasňují existenci opakujících se trendů v zakončení útočných akcí ve futsalu. Klíčová slova futsal, střelba, střelecká situace, kvantitativní a kvalitativní analýza Powered by TCPDF (www.tcpdf.org