1,103 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
ExoMol line lists-IV. The rotation-vibration spectrum of methane up to 1500 K
No full textA new hot line list is calculated for CH in its ground electronic state. This line list, called 10to10, contains 9.8 billion transitions and should be complete for temperatures up to 1500 K. It covers the wavelengths longer than 1 μm and includes all transitions to upper states with energies below hc · 18 000 cm and rotational excitation up to J = 39. The line list is computed using the eigenvalues and eigenfunctions of CH obtained by variational solution of the Schrödinger equation for the rotation-vibration motion of nuclei employing program TROVE and a new 'spectroscopic' potential energy surface (PES) obtained by refining an ab initio PES (CCSD(T)-F12c/aug-cc-pVQZ) through least-squares fitting to the experimentally derived energies with J = 0-4 and a previously reported ab initio dipole moment surface (CCSD(T)-F12c/aug-cc-pVTZ). Detailed comparisons with other available sources of methane transitions including HITRAN, experimental compilations and other theoretical line lists show that these sources lack transitions both higher temperatures and near-infrared wavelengths. The 10to10 line list is suitable for modelling atmospheres of cool stars and exoplanets. It is available from the CDS data base as well as at www.exomol.com
Updatable Probabilistic Evaluation of Failure Rates of Mechanical Components in Power Take-Off Systems of Tidal Stream Turbines
No full textThis paper presents a method for the probabilistic evaluation of the failure rates of mechanical components in a typical power take-off (PTO) system of a horizontal-axis tidal stream turbine (HATT). The method is based on a modification of the method of the influence factors, when base failure rates, relevant influence factors and, subsequently, resulting failure rates are treated as random variables. The prior (i.e., initial) probabilistic distribution of the failure rates of a HATT component is generated using data for similar components from other industries, while taking into account actual characteristics of the component and site-specific operating and environmental conditions of the HATT. A posterior distribution of the failure rate is estimated numerically based on a Bayesian approach as new information about the component performance in an operating HATT becomes available. The posterior distribution is then employed to obtain the updated mean and lower and upper confidence limits of the failure rate. The proposed method is illustrated by applying it to the evaluation of the failure rates of two key components of the PTO system of a typical HATT—main seal and main bearing. In particular, it is shown that uncertainty associated with the method itself has a major influence on the failure rate evaluation. The proposed method is useful for the reliability assessment of both PTO designs of new HATTs and PTO systems of operating HATTs
Efficient Compression Of Molecular Line Lists: Application Of `super-energies' To The Exomol Database
No full text%\begin{figure}
%\includegraphics[scale=0.5]{KOH_T3000K_SL_SE}
%\caption{KOH absorption cross sections at ~K, the weak part before and after compression and the relative error. }
%\label{f:KOH}
%\end{figure}
A new compression algorithm for the efficient storage of molecular line lists has been recently presented\footnote{R.~J. Hargreaves, I.~E. Gordon, M.~Rey, A.~V. Nikitin, V.~G. Tyuterev, R.~V.
Kochanov, L.~S. Rothman, \emph{Astrophys. J. Suppl.}, 2020, \textbf{247}, 55.}. The algorithm is based on the effective `super-energies' developed to produce a compact HITEMP line list for methane. This method assumes a set of artificial lower state (super-)energies and corresponding reference intensities for an approximate description of the temperature dependent molecular absorption (absorption coefficient) on a grid of wavenumbers. The super-energies compression is applied only to the majority (\%) of the lines representing the weaker, continuum part of the molecular absorption, while the strongest lines (\%) are preserved in the original form to maintain the accuracy of the line list.
Here we adopt and develop the HITEMP compression algorithm to be applicable to the ExoMol data format and generate new compressed line lists for SiO,\footnote{A.~Owens, E.~K. Conway, J.~Tennyson, S.~N. Yurchenko, \emph{Mon. Not. R. Astron. Soc.}, 2020, \textbf{495}, 1927--1933.} HO,\footnote{O.~L. Polyansky, A.~A. Kyuberis, N.~F. Zobov, J.~Tennyson, S.~N. Yurchenko, L.~Lodi, \emph{Mon. Not. R. Astron. Soc.}, 2018, \textbf{480}, 2597--2608.} KOH and NaOH.\footnote{A.~Owens, J.~Tennyson, S.~N. Yurchenko, \emph{Mon. Not. R. Astron. Soc.}, 2021, \textbf{502}, 1128--1135.} We find that using artificial Einstein A coefficients instead of reference intensities provides a more accurate description of the temperature dependence. A typical compression of a line list consisting of, e.g., 40 billions SiO lines is to about {40} million data points. Advantages and limitations of the `super-energies' approach will be discussed. The compressed molecular line lists will be included in the ExoMol database (\textsc{www.exomol.com}) and their use should greatly facilitate atmospheric retrievals in exoplanets and other hot astronomical bodies.
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The 8states dataset for 12C13C
No full textThe dataset is an archive of ExoMol page, https://exomol.com/data/molecules/C2/12C-13C/8states.Please check the reference details according to the following description or directly from the website.
NB: The html description skips data which are not included in the current version for the purpose of simplicity. Please check C2_12C13C_8states.md for detailed information.
Definitions file
12C-13C__8states.def[6.58 KB]
References:
1. Tennyson, J., Yurchenko, S. N., Al-Refaie, A. F., Clark, V. H. J., Chubb, K. L., Conway, E. K., Dewan, A., Gorman, M. N., Hill, C., Lynas-Gray, A. E., Mellor, T., McKemmish, L. K., Owens, A., Polyansky, O. L., Semenov, M., Somogyi, W., Tinetti, G., Upadhyay, A., Waldmann, I., Wang, Y., Wright, S., Yurchenko, O. P., "The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres", J. Quant. Spectrosc. Rad. Transf., 255, 107228 (2020). [https://doi.org/10.1016/j.jqsrt.2020.107228]
Spectroscopic Model
https://exomol.com/models/C2/12C-13C/8states/
8states: line list
The 8states calculated high-temperature line list for C2
12C-13C__8states.states.bz2[1.67 MB]8states (12C)-(13C) line list states file. The originally computed rovibronic energies have been replaced by more accurate (experimentally derived) MARVEL values from McKemmish et al., MNRAS 497, 1081 (2020).
12C-13C__8states.trans.bz2[146.83 MB]8states (12C)-(13C) line list transition file
References:
1. Yurchenko, S. N, Szabo, I., Pyatenko, E., Tennyson, J., "ExoMol line lists XXXI: Spectroscopy of lowest eights electronic states of C2", Monthly Notices of the Royal Astronomical Society 480, 3397-3411 (2018). [https://doi.org/10.1093/mnras/sty2050][18YuSzPy.C2]
8states: partition function
The 8states calculated high-temperature line list for C2
12C-13C__8states.pf[244.14 KB]8states (12C)-(13C) partition function
References:
1. Yurchenko, S. N, Szabo, I., Pyatenko, E., Tennyson, J., "ExoMol line lists XXXI: Spectroscopy of lowest eights electronic states of C2", Monthly Notices of the Royal Astronomical Society 480, 3397-3411 (2018). [https://doi.org/10.1093/mnras/sty2050][18YuSzPy.C2
Tropicoporus stratificans G. Coelho & Yurchenko
No full textTropicoporus stratificans G.Coelho & Yurchenko Phytotaxa 245 (2): 147 (2016). SPECIMEN EXAMINED. — Brazil, Alagoas State, Quebrangulo City, REBIO de PedraTalhada, on dead wood, 09°14’57.7”S, 36°25’39.7”W, 724 m, 14.VII.2019, V. R. T. Oliveira, (URM[URM94063]). REMARKS The specimens from Northeast (URM94063) (Fig. 9 E-H) and Southern Brazil (SMDB14731 and SMDB14732) clustered with good support in the ITS tree (PP = 1, bootstrap = 93%). Our collection differs from the original description and holotype illustrations mostly by the somewhat lanceolate setae (however dimensions are identical), and the presence of abundant rhomboid crystals immersed in the tube trama. The stratified basidioma, tendency to form elongated pores in vertical parts and the velutinate margin make T. stratificans a distinct species in the region.Published as part of X, Vitor, Lima, avier de, T, Virton Rodrigo, Oliveira, argino de, C, Nelson, Lima-Júnior, orreia de, C., José Ribamar, Oliveira-Filho, Santos, Carla, Lima, Nelson & Gibertoni, Tatiana Baptista, 2022, Taxonomy and phylogenetic analysis reveal one new genus and three new species in Inonotus s. l. (Hymenochaetaceae) from Brazil, pp. 1-21 in Cryptogamie, Mycologie 20 (1) on page 16, DOI: 10.5252/cryptogamie-mycologie2022v43a1, http://zenodo.org/record/782880
Resilience of Critical Infrastructure Systems to Floods:A Coupled Probabilistic Network Flow and LISFLOOD-FP Model
No full textIn this paper, a network-flow model was constructed to simulate the performance of interdependent critical infrastructure systems during flood hazards, when there is shortage of commodities such as electrical power and water. The model enabled us to control the distribution of commodities among different consumers whose demand cannot be fully met. Incorporating time-variance in the model allowed for evaluating the time evolution of the functional level of the infrastructure systems and quantifying their resilience. As a demonstration of the model’s capability, the network model was coupled with a raster-based hydraulic flooding model in the way of Monte Carlo simulations. It was then used to investigate the cascading effects of flood-related failures of individual infrastructure assets on the performance of the critical infrastructure systems of a coastal community under different flooding scenarios and future climate impacts. The coupled modelling framework is essential for correctly assessing the interdependences and cascading effects in the infrastructure systems in the case of flood hazards. While in the considered example, the extent of inundation becomes less severe with a changing climate, the risk to infrastructure does not recede because of the cascading effects. This behaviour could not be captured by the flood model alone
The UCTY dataset for 28Si36S
No full textThe dataset is an archive of ExoMol page, https://exomol.com/data/molecules/SiS/28Si-36S/UCTY.Please check the reference details according to the following description or directly from the website. NB: The html description skips data which are not included in the current version for the purpose of simplicity. Please check SiS_28Si36S_UCTY.md for detailed information. Definitions file 28Si-36S__UCTY.def[4.65 KB] References: 1. Tennyson, J., Yurchenko, S. N., Al-Refaie, A. F., Clark, V. H. J., Chubb, K. L., Conway, E. K., Dewan, A., Gorman, M. N., Hill, C., Lynas-Gray, A. E., Mellor, T., McKemmish, L. K., Owens, A., Polyansky, O. L., Semenov, M., Somogyi, W., Tinetti, G., Upadhyay, A., Waldmann, I., Wang, Y., Wright, S., Yurchenko, O. P., "The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres", J. Quant. Spectrosc. Rad. Transf., 255, 107228 (2020). [https://doi.org/10.1016/j.jqsrt.2020.107228] Spectroscopic Model https://exomol.com/models/SiS/28Si-36S/UCTY/ UCTY: line list UCTY line list for SiS. 28Si-36S__UCTY.trans.bz2[1.05 MB]UCTY (28Si)(36S) line list transitions 28Si-36S__UCTY.states.bz2[98.69 KB]UCTY (28Si)(36S) line list states References: 1. Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., "ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS] UCTY: partition function UCTY line list for SiS. 28Si-36S__UCTY.pf[122.07 KB]UCTY (28Si)(36S) line list partition function, 1 K grid. References: 1. Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., "ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS] {"references": ["Tennyson, J., Yurchenko, S. N., Al-Refaie, A. F., Clark, V. H. J., Chubb, K. L., Conway, E. K., Dewan, A., Gorman, M. N., Hill, C., Lynas-Gray, A. E., Mellor, T., McKemmish, L. K., Owens, A., Polyansky, O. L., Semenov, M., Somogyi, W., Tinetti, G., Upadhyay, A., Waldmann, I., Wang, Y., Wright, S., Yurchenko, O. P., \"The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres\", J. Quant. Spectrosc. Rad. Transf., 255, 107228 (2020). \[https://doi.org/10.1016/j.jqsrt.2020.107228](https://doi.org/10.1016/j.jqsrt.2020.107228)\", "Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., \"ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS\", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS]"]
The UCTY dataset for 29Si32S
No full textThe dataset is an archive of ExoMol page, https://exomol.com/data/molecules/SiS/29Si-32S/UCTY.Please check the reference details according to the following description or directly from the website. NB: The html description skips data which are not included in the current version for the purpose of simplicity. Please check SiS_29Si32S_UCTY.md for detailed information. Definitions file 29Si-32S__UCTY.def[4.65 KB] References: 1. Tennyson, J., Yurchenko, S. N., Al-Refaie, A. F., Clark, V. H. J., Chubb, K. L., Conway, E. K., Dewan, A., Gorman, M. N., Hill, C., Lynas-Gray, A. E., Mellor, T., McKemmish, L. K., Owens, A., Polyansky, O. L., Semenov, M., Somogyi, W., Tinetti, G., Upadhyay, A., Waldmann, I., Wang, Y., Wright, S., Yurchenko, O. P., "The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres", J. Quant. Spectrosc. Rad. Transf., 255, 107228 (2020). [https://doi.org/10.1016/j.jqsrt.2020.107228] Spectroscopic Model https://exomol.com/models/SiS/29Si-32S/UCTY/ UCTY: line list UCTY line list for SiS. 29Si-32S__UCTY.trans.bz2[1.02 MB]UCTY (29Si)(32S) line list transitions 29Si-32S__UCTY.states.bz2[94.13 KB]UCTY (29Si)(32S) line list states References: 1. Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., "ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS] UCTY: partition function UCTY line list for SiS. 29Si-32S__UCTY.pf[122.07 KB]UCTY (29Si)(32S) line list partition function, 1 K grid. References: 1. Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., "ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS] {"references": ["Tennyson, J., Yurchenko, S. N., Al-Refaie, A. F., Clark, V. H. J., Chubb, K. L., Conway, E. K., Dewan, A., Gorman, M. N., Hill, C., Lynas-Gray, A. E., Mellor, T., McKemmish, L. K., Owens, A., Polyansky, O. L., Semenov, M., Somogyi, W., Tinetti, G., Upadhyay, A., Waldmann, I., Wang, Y., Wright, S., Yurchenko, O. P., \"The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres\", J. Quant. Spectrosc. Rad. Transf., 255, 107228 (2020). \[https://doi.org/10.1016/j.jqsrt.2020.107228](https://doi.org/10.1016/j.jqsrt.2020.107228)\", "Upadhyay, A., Conway, E. K, Tennyson, J., Yurchenko, S. N., \"ExoMol line lists XXVI: A hot line list for silicon sulphide, SiS\", Monthly Notices of the Royal Astronomical Society 477, 1520-1527 (2018). [https://doi.org/10.1093/mnras/sty998][18UpCoTE.SiS]"]
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