42 research outputs found
ExoMol line lists - III. An improved hot rotation-vibration line list for HCN and HNC
No full textA revised rotation-vibration line list for the combined hydrogen cyanide (HCN)/hydrogen isocyanide (HNC) system is presented. The line list uses ab initio transition intensities calculated previously and extensive data sets of recently measured experimental energy levels. The resulting line list has significantly more accurate wavelengths than previous ones for these systems. An improved value for the separation between HCN and HNC is adopted, leading to an approximately 25 per cent lower predicted thermal population of HNC as a function of temperature in the key 2000 to 3000 K region. Temperature-dependent partition functions and equilibrium constants are presented. The line lists are validated by comparison with laboratory spectra and are presented in full as supplementary data to the article and at www.exomol.com
Fitting of a PES for rovibrational calculations on
No full textS.A. Tashkun and P. Jensen, J. Mol. Spec., 165, 173-184 (1994). O.L. Polyansky, P. Jensen and J. Tennyson, J. Chem. Phys., 101, 7651-7657 (1994)Author Institution: Department of Physics and Astronomy, University College London; Physikaliach-Chemisches Institut, Justus-Lieting-Universit\""{a}t GiessenWe took the potential energy surface for the ground electronic state of constructed by Tashkun and using the MORBID Hamiltonian and computer program. We wished to fit this experimental date using the exact kinetic energy (EKE) operator. Initially, EKE calculations were not not possible due to the presence of holes in the surface. A better starting point for the fit was constructed using the method in Polyansky whereby MORBID and EKE calculations are combined. We then improved the surface by fitting it to available experimental data using an iterative least-squares fitting procedure. In the low-energy region ( ) the fitting was successful. Above apporximately the higher electronic state begins to peturb the vibrational energy levels of the ground state. We were unable to fit the surface well to the experimental date above . We aim to provide a surface which will give accurate rovibrational levels of
Two preachings on Lazarus Saturday: The moral dimension of friendship according to Saint Justin (Polyansky) and Saint Innocent of Kherson
No full textIntroduction. The article is devoted to the concept of friendship in Christian ethics. The author analyses the idea of friendship and its moral aspect in two previously underexamined in Russian theology sermons of Saint Justin (Polyansky) and Saint Innocent of Kherson on Lazarus Saturday. Theoretical analysis. The research allows us to make the following conclusions. According to Saint Justin (Polyansky) and Saint Innocent of Kherson, friendship represents: the friendly love of the Lord Jesus Christ for His friends, the ideal of friendship for every Christian in the terms of one’s relations with neighbours; the friendly love of a human for God (sincerity and openness, service), which is impossible without the assistance of Divine grace, and which is rewarded by achieving the Divine friendship in relation to a human (salvation); friendship between a human and God, which is characterized by mutual sincerity and openness, and mutual service; human friendship, which is characterized by mutual sincerity and openness (confession of sins to each other), mutual service of love, patience with shortcomings, and compassion. Conclusion. According to Saint Justin and Saint Innocent, friendship has a moral dimension; it is a part of Christian morality, and the telos of the Christian moral life
IMPORTANCE OF RELATIVISTIC CORRECTIONS TO THE SPECTRUM OF WATER AND HYDROGEN SULPHIDE
No full text[1] J. Tennyson, P. Barletta, M.A. Kosten, O.L. Polyansky and N.F. Zobov, Spectrochimica Acta A 58 (2002) 663. [2] H.M. Quiney, P. Barletta, G. Tarczay, A.G. Cs\'{a}sz\'{a}r, O.L. Polyansky and J.Tennyson, Chem. Phys. Lett. 344 (2001) 413.Author Institution: Department of Physics and Astronomy, University College London; Department of Theoretical Chemistry, E\""{o}tv\""{o}s UniversityThe importance of effects as small as minor relativistic corrections in theoretical predictions of energy levels can be as high as few wavenumbers [1]. Two-electron relativistic corrections to the ground-state electronic energy of water and hydrogen sulphide are determined at over 300 (250) geometries. The corrections include the two-electron Darwin term of the Coulomb-Pauli Hamiltonian, and the Gaunt and Breit corrections, calculated perturbationally using four-component variational Dirac-Hartree-Fock wavefunctions. Fitted relativistic correction surfaces are constructed and used with an accurate ab initio nonrelativistic Born-Oppenheimer potential to calculate vibrational and rotational levels. The calculations suggest that these two-electron relativistic corrections, which have so far been neglected in rovibrational calculations on light molecules, have a substantial influence on the ro-vibrational levels [2]. The effects considered have markedly different characteristics for the stretching and bending levels
ANALYSIS OF HOT MOLECULAR SPECTRA
No full textAuthor Institution: Department of Physics and Astronomy, University College LondonRecent increases in accuracy of triatomic molecular energy level calculations for high rotational quantum numbers J is reviewed. Variational calculations which use exact kinetic energy operators can treat all vibrational states simultaneously. These calculations can use high quality ab initio and fitted potential energy surfaces. For spectroscopic accuracy on hydrogen containing molecules, it is necessary to include adiabatic and nonadiabatic corrections to the Born-Oppenheimer approximation. Relativistic corrections can also be important. Application of the resulting calculations of energy levels and spectra to the analysis of seemingly unassignable spectra of water and is described. Spectra of water in sunspot , laboratory and even room temperature contain hundreds or thousands of lines which remained unassigned for more than a decade (see for example Polyansky et al., Science, v. 277, N5324, pp. 346-348 (1997)). We present here the results of the assignments of these water lines. line assignment is also considered as well as progress on and the analysis of the spectra of other triatomic molecules
Multiple-resonance spectroscopy of high vibrational levels in water and methanol
No full textWe have measured the rovibrational levels in the electronic ground state of the water molecule at the previously inaccessible energies above 26000 cm-1. The use of laser double-resonance overtone excitation combined with laser-induced fluorescence (LIF) photofragment detection extends this limit to 34200 cm-1, which corresponds to 83% of the water dissociation energy. These data have allowed the theoretical group of Oleg Polyansky to generate a semiempirical potential energy surface on the basis of their ab initio surface [O. L. Polyansky, A. G. Csaszar, S. V. Shirin et al., Science 299 (5606), 539 (2003)] that now allows prediction of water levels with sub-cm-1 accuracy at any energy up to the new limit. A new ab initio potential energy surface is being constructed by Polyansky et al. that is intended to reproduce the rovibrational levels of water up to the dissociation threshold. We have calculated the electronic energy of ca. 2500 nuclear geometries at multireference configuration interaction level with 6Z basis set. We have performed a direct measurement of one of the most fundamental thermochemical values: the O-H bond energy in water. Using a triple-resonance laser excitation scheme, we excite the molecule through a series of vibrational overtone transitions to access directly the onset of the dissociative continuum. The dissociation energy obtained from our experiments, 41145.94 ± 0.15 cm-1, is ca. 30 times more accurate than the currently accepted value and has important implications for other thermochemical quantities linked to the bond energy of water. We have studied the conformational dependence of intramolecular vibrational redistribution in the 5v1 OH stretch overtone region of methanol. Previous state-selected spectra in the 5ν1 region [O. V. Boyarkin, T. R. Rizzo, and D. S. Perry, J. Chem. Phys. 110, 11346 (1999)] revealed a structure indicating an intramolecular vibrational redistribution on three time scales. Whereas in that work, methanol in the 5 v1 bright state was prepared close to the staggered conformation, methanol in the "partially eclipsed" conformation is prepared in our experiments by double resonance excitation through a torsionally excited intermediate state. We detect the excited molecules by infrared laser assisted photofragment spectroscopy (IRLAPS). In partially eclipsed methanol, the strong coupling of the v1 OH stretch to the v2 CH stretch becomes weaker, but the coupling responsible for the widths of the narrowest features becomes stronger.LCP
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Determining the probability of failure of marine diesel engine parts
No full textMaritime transportation is the essence of the international economy. Today, about ninety percent of world trade is carried out by sea through 50,000 merchant ships. Most of these vessels are powered by mainline diesel engines due to their reliability and fuel efficiency. Reliability of system elements in general depends on random failures, significant wear during operation, additional wear during start-up. Accidental damage to diesel engine components is a major hazard during operation, as some parts (such as cylinder liners and pistons) are usually replaced during repairs. On the other hand, preventive service does not eliminate random malfunctions. Therefore, in the general problem of assessing the reliability of a diesel engine, there is a mathematical problem of assessing the reliability and durability, taking into account only the random failures of its elements, which are of the greatest practical importance. The purpose of the work is a mathematical study of the reliability of parts of the cylinder-piston group of the main engines of dry cargo ships. Using a systematic approach and a probabilistic statistical method, it was established that the most common and difficult case is the simultaneous action on a system element (for example, a cylinder sleeve) of factors that cause wear during the period of operation (including during the start-up period) and accidental failures. It was determined that the quality of the cylinder-piston system in ships of the "Ostriv Rosiyskiy" type is higher than in the ships of the "Simferopol" and "Murom" types. Empirical formulas for estimating the probability of emergency failure of main engine system elements during the period of operation between factory repairs were obtained, where the main danger during the period of operation was carried by accidental failures. Based on the results of the study, it is possible to establish a schedule for the periodicity of maintenance of the ship's main engine and the cost of losses due to ship downtime due to failures, and can also be used in the reliability study of other types of ship's main engines. The results make it possible to determine the reliability of the parts of the cylinder-piston group of the main engines of dry cargo ships. and, in particular, to establish the maintenance schedule of the ship's main engine and the cost of damages due to ship downtime due to failures, and can also be used in the study of the reliability of other types of main engines of other series of ship
Collisionally-assisted spectroscopy of water from 27000 to 34000 cm-1
No full textWe report here an experimental approach that enables measurement of weak transitions to a wide range of rovibrational levels of water in the energy region 27000-34200 cm-1. We have previously demonstrated the use of laser double-resonance overtone excitation to access highly excited vibrational levels from single rovibrational states. While this approach simplifies the assignment of the spectra, it strongly reduces the number of observed transitions and hence our ability to test theoretical predictions. Here we increase significantly the number of observed transitions by allowing rotational and vibrational relaxation of H2O at intermediate levels of the double-resonance excitation scheme. Our recently developed semi- empirical potential energy surface PES12 (P. Maksyutenko, J. S. Muenter, N. F. Zobov, S. V. Shirin, O. L. Polyansky, T. R. Rizzo, and O. V. Boyarkin, J. Chem. Phys. 126, 241101 (2007)) enables assignment of the resulting complex spectra and reproduction of the measured transitions with sub-cm-1 accuracy.LCP
QUALITY MANAGEMENT OF HIGHER EDUCATION FOR INCREASING THE COMPETITIVENESS OF LABOUR RESOURCES
No full textThe objective of the research is empirical investigation of the priority components of increasing the competitiveness of labour resources in the quality management system of higher education based on the TQM concept. The methodology is based on the methods of comparative analysis, synthesis of strategic plans for the development of Ukrainian universities, the method of situational analysis (Case method) based on strategies and reports of universities’ leaders in the market of educational services in Ukraine. Results. In the process of empirical research, it has been proved that educational institutions are implementing the philosophy of total quality management (TQM) at three levels, namely: process, organizational and “a quality management principles level”. It has been determined that the classical universities of Ukraine are transformed into scientific and research centres that carry out innovative activities and cooperation at the international level, taking into account the requirements of the interested parties in order to ensure the competitiveness of graduates and their own competitive position in the educational market.Метою дослідження є емпіричне дослідження пріоритетних складових підвищення конкурентоспроможності трудових ресурсів у системі управління якістю вищої освіти на основі концепції TQM. Методологія базується на методах порівняльного аналізу, синтезі стратегічних планів розвитку університетів України, методі ситуаційного аналізу (Case method) на основі стратегій та звітів лідерів університетів на ринку освітніх послуг України. Результати. У процесі емпіричного дослідження було доведено, що навчальні заклади реалізують філософію загального управління якістю (TQM) на трьох рівнях, а саме: процесному, організаційному та «рівні принципів управління якістю». Визначено, що класичні університети України перетворюються на науково-дослідні центри, які здійснюють інноваційну діяльність та співпрацю на міжнародному рівні з урахуванням вимог зацікавлених сторін з метою забезпечення конкурентоспроможності випускників та власної конкурентоспроможності на освітньому ринку
The properties of coke breeze briquettes produced by ram briquetting
No full textThe paper reports on the results of briquetting coke breeze with a binder in a closed cylindrical press-die. Liquid glass is used as a binder. Approximating curves for the "compaction ratio vs. compaction pressure" dependences are plotted from experimental data. The mechanical properties of the briquettes are determined, namely, drop damage resistance and breaking stress. The results are presented as approximating dependences in the form of a power function. © 2017 Author(s)
