LASER ABLATION OF SOLID ORGANIC PRECURSORS AS AN ALTERNATIVE TOOL IN THE GENERATION OF INTERSTELLAR MOLECULES

In the course of the investigation of the rotational spectrum of prebiotic hydantoic acid by Fourier transform microwave spectroscopy coupled to a laser ablation source in a supersonic expansion, rotational signatures of two cyclic molecules, hydantoin and 2,5-oxazolidinedione, have been unexpectedly observed along with the four most stable conformers of hydantoic acid.\footnote{Kolesniková, L.; León, I.; Alonso, E. R. et al.: \textit{J. Phys. Chem. Lett.} \textbf{2019}, accepted, DOI: 10.1021/acs.jpclett.9b00208.} Interestingly, two of them presented folded geometric arrangements that might act as precursors in the cyclization reactions assisted by laser ablation. They could play the role of near-attack conformations (NACs) in the framework of the NAC theory for intramolecular reactions. A detailed analysis of the spectrum further revealed the simultaneous formation of other species in the jet, showing that the laser ablation of solid organic precursors constitutes an alternative tool in the generation of new chemical species.$^{b}$ It has been recently confirmed using diaminomaleonitrile as a solid precursor. Up to 30 different species (most of them detected in space) have been revealed in the supersonic expansion of our laser ablation chirped pulse Fourier transform microwave LA-CP-FTMW experiment

THE LABORATORY ROTATIONAL STUDY OF METHYL ISOCYNATE

Methyl isocyanate (CH$_{3}$NCO) is one of the most abundant species detected on the surface of the 67P/Churyumov-Gerasimenko comet.\footnote{Goesmann, F., Rosenbauer, H., Bredehoft, J.H., et al. 2015, Science, 349, aab0689.} It has also been discovered in space towards the Orion clouds where a large number of rotational lines arising from energy levels with $K \leq 3$ were reported.\footnote{Cernicharo, J., Kisiel, Z., Tercero, B., et al. 2016, A\&A, 587, L4.} In the present work, Stark-modulation spectroscopy was used to record the room temperature rotational spectrum of CH$_{3}$NCO in the spectral region from 32 to 90 GHz and to assign rotational transitions up to $K$ = 10. These new assignments were subsequently followed up to 364 GHz. Also, first laboratory measurements between 50 and 300 GHz have been performed for CH$_{3}$N$^{13}$CO and $^{13}$CH$_{3}$NCO isotopologues. Updated extensive line lists along with new sets of spectroscopic parameters provided in this work meet the needs for further detections of CH$_{3}$NCO in space

THE CONFORMATIONAL PANORAMA OF MANDELIC ACID

The conformational landscape of mandelic acid (phenyl glycolic acid), the simplest alpha-hydroxy acid containing an aromatic substituent, has been unveiled by laser ablation coupled with broadband Fourier transform microwave spectroscopy LA-CP-FTMW. The four identified conformers provide the first global structural picture of this molecule traditionally used in cosmetics and dermatology as well as in the synthesis of pharmaceuticals. Rotational transitions of singly substituted $^{13}$C isotopic species of the most stable conformer in its natural abundances were also detected, providing insight on its geometry

LASER ABLATION OF SOLID ORGANIC PRECURSORS: AN INNOVATIVE APPROACH FOR THE LABORATORY GENERATION OF CHEMICAL SPECIES

The high amount of reactive species participating in the chemistry in the Earth$^{'}$s upper atmosphere, interstellar medium, or combustion processes motivates laboratory experimentalists to develop efficient methods for the molecular \textit{in situ} generations to characterize these species spectroscopically. In the present contribution, we propose a new approach based on the laser ablation of solid organic compounds. A proof-of-concept experiment is performed using diaminomaleonitrile and uridine as prototypical precursors. Once formed in the throat of our laser ablation source, the products are entrained in the carrier gas, stabilized in the cold environment of the supersonic expansion, and are monitored by high-resolution chirped pulse Fourier transform microwave spectroscopy. We experimentally demonstrate a simultaneous formation of an impressive number and variety of species, both known and unknown. With these inspiring achievements in hands, we extend the boundaries for the molecular \textit{in situ} generations beyond traditional techniques such as electric discharge and pyrolysis

Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is $\simeq$ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.Comment: Accepted for publication in ApJL (30 January 2014)/ submitted (8 January 2014

Searching for Trans Ethyl Methyl Ether in Orion KL

We report on the tentative detection of $trans$ Ethyl Methyl Ether (tEME), $t-CH_3CH_2OCH_3$, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for $gauche$-$trans$-n-propanol, $Gt-n-CH_3CH_2CH_2OH$, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are $\leq(4.0\pm0.8)\times10^{15} cm^{-2}$ and $\leq(1.0\pm0.2)\times10^{15} cm^{-2}$ for tEME and Gt-n-propanol, respectively. The rotational temperature is $\sim100 K$ for both molecules. We also provide maps of $CH_3OCOH$, $CH_3CH_2OCOH$, $CH_3OCH_3$, $CH_3OH$, and $CH_3CH_2OH$ to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio $N(CH_3OCH_3)/N(tEME)\geq150$ in the compact ridge of Orion.Comment: Accepted in A&A Letter

Microsurfacing using Reclaimed Asphal Pavement

Silniční síť v ČR je téměř 55 738 km a její údržba je dlouhodobě podfinancována. Je tedy zapotřebí hledat způsoby, jak prodloužit celkovou životnost komunikací. Emulzní mikrokoberce patří mezi emulzní kalové vrstvy a jsou tvořeny tenkou vrstvou ze směsi kameniva, asfaltové emulze, vody a regulátory štěpitelnosti (např. cement, vápno apod.). Jedná se o údržbovou technologii vozovek sloužící k prodloužení životnosti vozovek, a to o 5 až 9 let. S tím, jak postupně dochází ke snižování zásob kvalitního kameniva a k růstu cen vstupních surovin pro mikrokoberce, je třeba se zabývat možností využití R-materiálu do této technologie. Práce se zabývá nahrazením přírodního kameniva v mikrokobercích R-materiálem, a to v množství 100 %. V rámci praktické části práce byla optimalizována receptura mikrokoberce s R-materiálem.The road network in the Czech Republic is almost 55,738 km long and its maintenance has been underfunded for a long time. It is therefore necessary to look for ways to extend the overall service life of roads. Microsurfacings belong to the emulsion slurry layers and are made up of a thin layer of a mixture of aggregate and modified asphalt emulsion. It is a pavement maintenance technology used to extend the service life of pavements by 5 to 9 years. As the supply of quality aggregate is gradually decreasing and the price of feedstock for microsurfacing is increasing, the possibility of incorporating R-material into this technology needs to be addressed. This thesis deals with the replacement of natural aggregates in microsurface R-material in the amount of 100 %. In the framework of the work, the formulation of the microsurface with R-material was optimized.

Komparace marketingové strategie vybraných cestovních kanceláří

Cílem této práce je porovnat marketingovou strategii vybraných cestovních kanceláří. Komparace je založena především na metodě pozorování a provedení mystery shoppingu. Jsou analyzovány jednotlivé složky marketingového mixu. Zjištěná "image" těchto cestovních kanceláří je ověřena dotazníkovým šetřením mezi potenciálními zákazníky. Závěrem je odhadnuta segmentace zákazníků, kterou cestovní kanceláře uplatňují a jsou stanoveny návrhy do budoucna