4,331 research outputs found
Petr Simon (1944-2018)
No full textThis article is a reflection on the mathematical legacy of Professor Petr Simon.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Analysi
Effect of Fiber Orientation on the Tribological Performance of Abaca-Reinforced Epoxy Composite under Dry Contact Conditions
No full textThis paper presents tribological research of an abaca fiber-reinforced epoxy composite material, analyzing fiber orientation and its effect on the tribological performances of the composite. The extremely low viscosity epoxy resin reinforced with NaOH-treated long abaca fibers is investi- gated under the different operating conditions. The unidirectional abaca fibers reinforced the epoxy resin and formed composite specimens with fibers in three directions, parallel (P-O), anti-parallel (AP-O) and normal (N-O), while keeping the sliding direction. The specimens were fabricated using fiber volume fractions of 10 vol%, 20 vol% and 30 vol% using the vacuum infusion technique. The block-on-disc (BOD) apparatus has been used to exhibit the tribological tests. Normal loads of 35 N and 45 N have been used for testing purposes. The experimental results indicated that the presence of abaca fiber significantly improved the wear characteristics of the matrix. An increased coefficient of friction was observed in samples with anti-parallel-oriented fibers at an applied load of 35 N. The conducted research shows that the use of abaca fibers as fillers could improve the tribological characteristics of the epoxy resin-based composite material
Friction and wear characterization of a new ecological composite: glass waste beads reinforced epoxy
No full textSandblasting is a process that allows smoothing and cleaning rough surfaces, by means of a hard abrasive material streamed at high pressure against the interested surface. The abrasive material could be glass beads, which are wasted after the process. This paper investigated the opportunity to recycle the glass beads as reinforcement inside a polymeric matrix. This new composite material could be an economic and green alternative to the more common polymer matrix composite (PMC). Therefore, the tribological properties of this composite were studied through reciprocating sliding tribotest. The influence on friction and wear of different glass dimensions and concentrations within epoxy resin were analyzed
Analytical fluid film force calculation in the case of short bearing with a fully developed turbulent flow
No full textThe main purpose of this paper is to define a methodology to determine the analytical approximate closed-form expression of non-steady fluid film force and of the oil film coefficients for the liquid-lubricated journal bearings in the case of a fully developed turbulent flow regime. The considered model is a symmetrical rigid rotor supported on two lubricated journal bearings; this paper considers the cases of the short bearing approximation, introducing the turbulence correction flow factors in the classical Reynolds equation. The proposed methodology gives the opportunity to solve in approximate way the equation governing the distribution of pressure in the bearing oil gap and then to obtain the closed- form expressions for the non-steady fluid forces. This approach shows the benefit of minimising the calculation time required for the non-linear dynamic analysis of rotors on turbulent journal bearings without any significant loss of accuracy giving a better readability of the parameter involved on the system behaviour
Centralization of treasury management 2010
No full textThe book consists of five parts: 1. Treasury management and its responsibilities (Chapter 1‐4); 2. Decentralized treasury (Chapter 5); 3. Different phases of the centralization (Chapter 6‐9); 4. Outsourcing (Chapter 10) 5. Regional treasury centres (Chapter 11); 6. Best practices in a bank (Chapter 12); In the first part, the author describes the treasury management focusing on its three core responsibilities, such as assets and liabilities management, cash management, and financial risk management. The second part zooms in on decentralized treasury and decisions about the appropriate degree of centralization/decentralization of the treasury activities. Then we focus on the different phases of the process of centralization, from central interest rate and foreign exchange management through centralization of cash and liquidity management, then transaction processing up to fully centralized treasury. In part four we continue by discussing outsourcing as the next stage following centralization to achieve additional economic benefits. The fifth part contains especially a number of the location criteria, both tax and non‐tax, that must be evaluated during consideration where to establish the regional treasury centre. The last part deals with banking best practices in cash pooling from the point of view of the author that works in one of the top banks in Central and Eastern Europe region
Cyclometalation of phenylpyridines with a ferrocenyl group
No full textNázev práce: Cyklometalace fenylpyridinů s ferrocenylovým substituentem Autor: Bc. Petr Harmach Katedra: Katedra anorganické chemie Vedoucí diplomové práce: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstrakt: Cílem této práce byla příprava cyklometalovaných komplexů fenylpyridinů s ferrocenylovým substituentem. Cyklometalované komplexy mají široké spektrum využití, kdy jedním z nejvýznamnějších je použití v katalýze. Připraveny byly iridité a rhodité cyklometalované komplexy s elektrondonorními nebo elektronakceptorními skupinami na pyridinovém kruhu. Všechny tyto látky byly charakterizovány 1 H a 13 C{1 H} NMR spektroskopií, hmotnostní spektrometrií, elementární analýzou a cyklickou voltametrií. U dvou připravených látek byly jejich struktury potvrzeny pomocí metody difrakce rentgenového záření na monokrystalech. Klíčová slova: cyklometalace, pyridin, C-H aktivace, ferrocenTitle: Cyclometalation of phenylpyridines with a ferrocenyl group Author: Bc. Petr Harmach Department: Katedra anorganické chemie Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: The objective of this thesis was the synthesis of cyclometalated complexes of phenylpyridine with a ferrocenyl group. Cyclometalated complexes have a wide range of application, where one of the most important is the use in catalysis. Iridium(III) and rhodium(III) cyclometalated complexes were prepared containing electron-donating or electron-accepting groups on the pyridine ring. All newly prepared complexes were characterized by 1 H a 13 C{1 H} NMR spectroscopy, mass spectrometry, elemetal analysis and cyclic voltammetry. The structures of two complexes were determined by single-crystal X-ray diffraction analysis. Key words: cyclometalation, pyridine, C-H activation, ferroceneDepartment of Inorganic ChemistryKatedra anorganické chemiePřírodovědecká fakultaFaculty of Scienc
Adaptivní volba parametrů stabilizačních metod pro rovnice konvekce-difúze
No full textTitle: Adaptive choice of parameters in stabilization methods for convection- diffusion equations Author: Bc. Petr Lukáš (e-mail: [email protected]) Department: Department of Numerical Mathematics Supervisor: Doc. Mgr. Petr Knobloch, Dr. (e-mail: [email protected]) Abstract: The aim of the work is to propose suitable approaches for adap- tive choice of parameters in stabilization methods for convection-difusion equations discretized by the finite element method. We introduce the L-SR1 method, compare it with other nonlinear methods of minimizing functions with large number of variables, and introduce and compare the adaptive methods based on minimizing of the error indicator. Keywords: Adaptive choice of parameters, finite element method, stabiliza- tion methods, convection-diffusion equation, L-SR1 method, error indicato
Cyclometalation of phenylpyridines with a ferrocenyl group
No full textTitle: Cyclometalation of phenylpyridines with a ferrocenyl group Author: Bc. Petr Harmach Department: Katedra anorganické chemie Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: The objective of this thesis was the synthesis of cyclometalated complexes of phenylpyridine with a ferrocenyl group. Cyclometalated complexes have a wide range of application, where one of the most important is the use in catalysis. Iridium(III) and rhodium(III) cyclometalated complexes were prepared containing electron-donating or electron-accepting groups on the pyridine ring. All newly prepared complexes were characterized by 1 H a 13 C{1 H} NMR spectroscopy, mass spectrometry, elemetal analysis and cyclic voltammetry. The structures of two complexes were determined by single-crystal X-ray diffraction analysis. Key words: cyclometalation, pyridine, C-H activation, ferrocen
Synthesis of gold(I) carbene complexes from isocyanoferrocene
No full textTitle: Synthesis of gold(I) carbene complexes from isocyanoferrocene Author: Petr Harmach Department: Katedra anorganické chemie Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: The objective of this bachelor thesis was the synthesis of gold(I) carbene complexes. These complexes were synthetised from a newly prepared gold(I)-isocyanoferrocene complex and also directly from isocyanoferrocene. Carbene complexes were obtained from primary and secondary amines, and therefore complexes contain disubstituted or trisubstituted diaminocarbene moieties. All newly prepared complexes were characterized by NMR spectroscopy, mass spectrometry, elemental analysis and infrared spectroscopy. The structures of the majority of the prepared complexes were confirmed by single-crystal X-ray diffraction analysis. Key words: isocyanides, ferrocene, carbenes, gold(I) complexe
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