Clear sky fraction above Indonesia: an analysis for astronomical site selection

We report a study of cloud cover over Indonesia based on meteorological satellite data, spanning over the past 15 years (from 1996 to 2010) in order to be able to select a new astronomical site capable to host a multi-wavelength astronomical observatory. High spatial resolution of meteorological satellite data acquired from {\it Geostationary Meteorological Satellite 5} ({\it GMS 5}), {\it Geostationary Operational Environmental Satellite 9} ({\it GOES 9}), and {\it Multi-functional Transport Satellite-1R} ({\it MTSAT-1R}) are used to derive yearly average clear fractions over the regions of Indonesia. This parameter is determined from temperature measurement of the IR3 channel (water vapor, 6.7 $\mu$m) for high altitude clouds (cirrus) and from the IR1 channel (10.7 $\mu$m) for lower altitude clouds. Accordingly, an algorithm is developed to detect the corresponding clouds. The results of this study are then adopted to select the best possible sites in Indonesia to be analysed further by performing in situ measurements planned for the coming years. The results suggest that regions of East Nusa Tenggara, located in south-eastern part of Indonesia, are the most promising candidates for such an astronomical site. Yearly clear sky fraction of this regions may reach better than 70 per cent with an uncertainty of 10 per cent.Comment: 15 pages, 13 figures, and 4 table

Reactions of methylamines with hydrogen halogenides and their applications in the synthesis of coordination compounds

V magistrskem delu smo raziskovali derivate amonijaka, in sicer metilamine (dimetilamine, trimetilamine in tetrametilamine) ter njihove koordinacijske spojine. Predpostavili smo, da bodo metilamini (dimetilamini, trimetilamini in tetrametilamini) tvorili trdne produkte z vodikovimi halogenidi, kjer smo izbrali halogeni element klor. Reaktante smo sintetizirali z reakcijo nevtralizacije pri sobni temperaturi ter s segrevanjem na vodni kopeli. Reakcija med metilaminom ter klorovodikovo kislino je bila uspešna, tako da smo dobljeni produkt metilamonijev klorid karakterizirali ter potrdili z rentgensko monokristalno analizo. Ostali produkti reakcij so bili neobstojni, tako da smo jih označili za neuspešne sinteze. Glede na to, da se metilamini (dimetilamini in trimetilamini) obnašajo podobno kot amonijak, smo jih uporabili pri tvorbi koordinacijskih spojin. Za centralni atom smo izbrali baker, ki smo ga dodajali v obliki bakrovih(II) spojin (CuSO4·5H2O, Cu(CH3COO)2,Cu(CH3COO)2·H2O ter CuCl2). Sinteze koordinacijskih spojin so potekale pri različnih množinskih razmerjih (1:1, 2:1 ter 4:1) in različnih topilih (metanol, etanol, destilirana voda ter acetonitril). Sinteze reaktantov smo izvedli z mešanjem pri sobni temperaturi ter z reakcijo na refluksu. Za karakterizacijo nastalih kristalov smo uporabili termogravimetrično metodo (TGA) in monokristalno rentgensko analizo. Uspešno smo sintetizirali štiri nove spojine, katerim smo določili pripadajočo strukturo ter jih opisali. Ostali analizirani vzorci so se izkazali za že znane spojine, katerih strukture so karakterizirane ter opisane v člankih.In this master thesis ammonia derivatives, namely methylamine (dimethylamine, trimethylamine and tetramethylamine) and their coordination compounds were investigated. We assumed that methylamines (dimethylamines, trimethylamines and tetramethylamines) will form solid products with hydrogen halide, where the selected halide element was chlorine. Neutralization reaction with elevated temperature and at room temperature was used to synthesize the reactants. Reaction between methylamine and hydrogen chloride was successful, and the obtained product methylammonium chloride was characterised and confirmed with single crystal X-ray diffraction analysis. Other products of reactions were unstable and unsuccessful. Considering that methylamines (dimethylamines and trimethylamines) behave similar to ammonia, we used them to form coordination compounds. Copper was used as the central atom and added as copper(II) compounds (CuSO4·5H2O, Cu(CH3COO)2,Cu(CH3COO)2·H2O and CuCl2). For the synthesis of coordination compounds, we used different molar ratios (1:1, 2:1 and 4:1) and solvents (distilled water, ethanol, methanol and acetonitrile). We synthesized reactants with stirring at room temperature and with reaction of reflux. Formed crystals were characterised with thermogravimetric analysis (TGA) and single crystal X-ray diffraction analysis. We successfully synthesised four new compounds, to which we determined corresponding structure. Other analysed samples were already known compounds, which we can find characterised and described in different articles

Preparation of Zn, Ni and Co tellurides using high-temperature and mechanochemical methods

V tej diplomski nalogi smo poskušali sintetizirati Ni, Co in Zn teluride v različnih množinskih razmerjih in s pomočjo različnih metod. Uporabljali smo mehanokemijsko metodo, termogravimetrično metodo in diferenčno dinamično kalorimetrijo. Vzorce smo analizirali s pomočjo rentgenske praškovne difrakcije in rezultate predstavili v obliki difraktogramov. V delu so opisani postopki in metode, s pomočjo katerih smo prišli do rezultatov. Želeli smo pokazati, da sta mehanokemijska in termogravimetrična metoda skupaj učinkoviti.The main purpose of this diploma thesis is to synthese Ni, Co and Zn tellurides with different stoichiometries using various methods. We used mechanochemical method, thermogravimetric method (TGA) and differencial scanning calorimetry (DSC). The samples were analized with X-ray powder diffraction (XRD) and the results are displayed in diffraction patterns. In this diploma thesis all the methods that we used are described. We wanted to prove that mechanochemical and thermogravimetric method when used together are effective

Djurnal Atmospheric Extinction Over Oukaïmeden, Observatory Using IRIS Database : 1989-1997

Experimental Astronomy, 13/3, (2003)International audienc

First astronomical preselecting site in the Beni Mellal region: On the use of satellite data

In this paper we use satellite meteorological and geophysical data to compare three new sites to the Oukaimeden Observatory (J43) located in the Atlas mountains (Morocco). The Three other sites are located in Beni Mellal mountains. The data are obtained from several satellites: MODIS (Moderate Resolution Imaging Spectroradiometer), AIRS (the Atmospheric Infrared Sounding System). Those three sites, located on the middle Atlas Mountain, are not far from the University of Beni Mellal by good roads. As results, we find that these three sites are of good quality and can be qualified to house some astronomical instruments, but in situ data are required. We will install some astronomical instrumentation to measure the nocturnal extinction and the seeing