546 research outputs found

    A Fundamental Study of Smoldering Combustion in Microgravity

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    A research program is being conducted to study smoldering combustion in microgravity. The program's final objective is to design and conduct smolder experiments in a space based laboratory, which will complement normal gravity ones, and that will help to: increase the current fundamental understanding of smoldering; predict smolder behavior in a space-based installation; and prevent and control smolder originated, ground or space based, fires

    Building up a membrane photonics platform in Indium phosphide

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    Aspek Hukum Cendana Dan Perilaku Masyarakat NTT

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    Cendana sebagai komoditi bernilai ekonomi tinggi yang persebaran alaminya terdapat di Nusa Tenggara Timur (NTT), merupakan kebanggaan masyarakat setempat. Nilai ekonomi tanaman cendana terdapat pada kayu gubal, teras, serbuk dan ampas serta minyak cendana. Kayu cendana digunakan untuk kerajinan dan minyak cendana untuk obat-obatan dan kosmetik. Dampak dari nilai ekonomi yangtinggi adalah sering terjadinya penebangan secara liar (tidak terkontrol), sehingga kehidupannya semakin terancam. Penebangan yang tidak terkendali ini tidak memperdulikan aturan-aturan yang berlaku baik dari segi tertib hukum maupun dari segi konservasi seperti ukuran lingkar batang, umur tanaman dan intensitas penebangan. Dilihat dari umur cendana yang berkualitas bagus dapat ditebang pada umur berkisar 40-50 tahun. Walaupun cendana cukup berpotensi karena harga jual yang cukup menjanjikan tetapi tidak membuat kesejahteraan hidup masyarakat meningkat. Hal ini karena monopoli pemerintah terus berlanjut bagi tanaman cendana yang tumbuh di pekarangan maupun lahan lainnya milik masyarakat; sehingga terjadi masalah yang cukup serius mengenai cendana ini bila dilihat dari segi ekonomi,ekologi serta perilaku masyarakat. Selanjutnya bagaimana hukum pengelolaan cendana dan bagaimana perilaku masyarakatnya dengan berlakunya ketentuan hukum tentang cendana di NTT. Dibutuhkan tertib hukum yang menyangkut aspek yuridis seperti hak dan kewajiban, kedudukan hukum, peran serta masyarakat serta kepatuhan masyarakat. Dapat disimpulkan bahwa pemerintah sebagai penanggungjawab penyelenggaraan pengelolaan cendana di NTT belum mengadopsi azas-azas hukum umum pengelolaan sumber daya alam hayati (SDAH) yang berlaku di Indonesia. Adanya pengaturan hukum yang memberikan hak mengelola cendana kepada Pemerintah Daerah mengakibatkan penyimpangan yang lebih merugikan cendana dan habitatnya di NTT. Sosialisasi hukum lingkungan dan peraturan lingkungan lainnya perlu segera disosialisasikan kepada seluruh masyarakat NTT

    Very High-Redshift Lensed Galaxies

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    We review in this paper the main results recently obtained on the identification and study of very high-z galaxies usinglensing clusters as natural gravitational telescopes. We present in detail our pilot survey with ISAAC/VLT, aimed at the detection of z>7 sources. Evolutionary synthesis models for extremely metal-poor and PopIII starbursts have been used to derive the observational properties expected for these high-z galaxies, such as expected magnitudes and colors, line fluxes for the main emission lines, etc. These models have allowed to define fairly robust selection criteria to find z~7-10 galaxies based on broad-band near-IR photometry in combination with the traditional Lyman drop-out technique. The first results issued from our photometric and spectroscopic survey are discussed, in particular the preliminary confirmation rate, and the global properties of our high-z candidates, including the latest results on the possible z=10.0 candidate A1835-1916. The search efficiency should be significantly improved by the future near-IR multi-object ground-based and space facilities. However, strong lensing clusters remain a factor of ~5-10 more efficient than blank fields in this redshift domain, within the FOV of a few arcminutes around the cluster core, for the typical depth required for this survey project.Comment: 14 pages, 7 figures, Proceedings of IAU Symposium No. 225: The Impact of Gravitational Lensing on Cosmology, Y. Mellier and G. Meylan, Ed

    Las dos etapas principales de deformaciĂłn herciana en la Cordillera CantĂĄbrica y el trazado de sus estructuras

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    Se ha insistido repetidamente por parte de diferentes autores en las fases de plegamiento que han afectado al Paleozoico de la Cordillera CantĂĄbrica (DE SITTER, 1961, 1962; LLOPIS, 1964; WAGNER 1966) sin que exista un acuerdo en la cronologĂ­a o nĂșmero de estas fases. El objeto de esta nota no es entrar a discutir el problema de la cronologĂ­a de las deformaciones hercinianas, sino dar algunas precisiones sobre el trazado de las estructuras paleozoicas de la Cordillera CantĂĄbrica (cuya unidad se ha impugnado en algunos trabajos, desde diferentes puntos de vista; DE SITTER, 1962; LLOPIS, 1964) y poner de relieve algunas de las consecuencias que de ello se derivan

    ISAAC/VLT observations of a lensed galaxy at z=10.0

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    We report the first likely spectroscopic confirmation of a z 10.0 galaxy from our ongoing search for distant galaxies with ISAAC/VLT. Galaxy candidates at z >~ 7 are selected from ultra-deep JHKs images in the core of gravitational lensing clusters for which deep optical imaging is also available, including HST data. The object reported here, found behind Abell 1835, exhibits a faint emission line detected in the J band, leading to z=10.0 when identified as Ly-a, in excellent agreement with the photometric redshift determination. Redshifts z < 7 are very unlikely for various reasons we discuss. The object is located on the critical lines corresponding to z=9 to 11. The magnification factor \mu ranges from 25 to 100. For this object we estimate SFR(Ly-a) (0.8-2.2) Msun/yr and SFR(UV) (47-75) Msun/yr, both uncorrected for lensing. The steep UV slope indicates a young object with negligible dust extinction. SED fits with young low-metallicity stellar population models yield (adopting mu=25) a lensing corrected stellar mass of M*~8.e+6 Msun, and luminosities of 2.e+10 Lsun, corresponding to a dark matter halo of a mass of typically M_tot>~ 5.e+8 Msun. In general our observations show that under excellent conditions and using strong gravitational lensing direct observations of galaxies close to the ``dark ages'' are feasible with ground-based 8-10m class telescopes.Comment: To be published in A&A, Vol. 416, p. L35. Press release information, additional figures and information available at http://obswww.unige.ch/sfr and http://webast.ast.obs-mip.fr/galaxie
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