1,211 research outputs found

    Efficient Synthesis of Aromatic Quinoxaline Derivatives

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    Quinoxaline and its derivatives have many antimicrobial properties that make them possible substitutes for current medication, with abilities including antibacterial, anticancer, antiviral, and antifungal among others [1]. It is important to be able to quickly and effectively develop new compounds. Current methods to synthesize quinoxaline derivatives are cumbersome, with long reaction times, low yields, and required solvents that add hazards and costs. Microwave-assisted synthesis is a novel methodology to synthesize quinoxaline derivatives in only 5 minutes with no solvent. This study analyzes microwave irradiation as a synthesis technique

    The Application of Landsat TM Data and SRTM Data for Detection Vulnerability Assessment of Flood in Bengawan Solo Watershed

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    Bengawan Solo watershed is one of watershed that has frequent floods. Due to high rainfall in the rainy season, the river can't accommodate the surface runoff and resulted flooding around the area. The high rainfall is not only causing flood in some areas upstream watershed, but also threaten the downstream areas in East Java province, especially Bojonegoro, Lamongan, Tuban and Gresik. Data of remote sensing and Geographic Information System (GIS) could detect assessment vulnerability of flooding. The research objective is to study flood vulnerability assessment in Bengawan Solo watershed using remote sensing data. The method is the combination of information from remote sensing data, i.e.. (1) to combine band 4 with band 7 Landsat TM in which the flood pixel value is ≤ 78; (2) to detect flow accumulation using SRTM data; and (3) to detect flooding areas at the altitude of 0-50 m. The result obtained from the study is the flood vulnerability in Bengawan Solo watershed including Sragen District (Masaran, Plupuh, Gesi, Sidoharjo Sub District); Ngawi (Widodaren, Kedungalar, Pitu SubDistrict); Tuban District (Rengel, Plumpang, Widang Sub District); Bojonegoro (Padangan, Malo, Kalitidu, Trucuk, Bojonegoro,Dander, Kanor, Baureno, Sumberejo Sub District); Lamongan (Laren, Solokuro, Karanggeneng, Kalitengah Sub District); Gresik Regency (Hamlet and Bungah Sub District)

    Australia Telescope Compact Array Radio Continuum 1384 and 2368 Mhz Observations of Sagittarius B

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    We present images of the Sagittarius (Sgr) B giant molecular cloud at 2368 and 1384 MHz obtained using new, multi-configuration Australia Telescope Compact Array (ATCA) observations. We have combined these observations with archival single-dish observations yielding images at resolutions of 47" by 14" and 27" by 8" at 1384 and 2368 MHz respectively. These observations were motivated by our theoretical work (Protheroe et al. 2008) indicating the possibility that synchrotron emission from secondary electrons and positrons created in hadronic cosmic ray (CR) collisions with the ambient matter of the Sgr B2 cloud could provide a detectable (and possibly linearly polarized) non-thermal radio signal. We find that the only detectable non-thermal emission from the Sgr B region is from a strong source to the south of Sgr B2, which we label Sgr B2 Southern Complex (SC). We find Sgr B2(SC) integrated flux densities of 1.2+/-0.2 Jy at 1384 MHz and 0.7+/-0.1 Jy at 2368 MHz for a source of FWHM size at 1384 MHz of ~54". Despite its non-thermal nature, the synchrotron emission from this source is unlikely to be dominantly due to secondary electrons and positrons. We use polarization data to place 5-sigma upper limits on the level of polarized intensity from the Sgr B2 cloud of 3.5 and 3 mJy/beam at 1384 and 2368 MHz respectively. We also use the angular distribution of the total intensity of archival 330 MHz VLA and the total intensity and polarized emission of our new 1384 MHz and 2368 MHz data to constrain the diffusion coefficient for transport of the parent hadronic CRs into the dense core of Sgr B2 to be no larger than about 1% of that in the Galactic disk. Finally, we have also used the data to perform a spectral and morphological study of the features of the Sgr B cloud and compare and contrast these to previous studies.Comment: 7 pages, 4 figures, matches version published in the Astronomical Journa

    Respon GA3 Terhadap Induksi Tunas Mikro Tanaman Karet (Hevea Brasiliensis (Muell). Arg)

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    The aim of the research was to know effect of GA3 to rubber plant in micro shoot formation. The research was conducted at the rubber plant microcutting labortory PT Perkebunan Nusantara III Kebun Gunung Pamela, Tebing Tinggi, North Sumatera, Indonesia from April 2015 to Juli 2015. The Completely randomize design was used with two factors,i.e.:the addition of GA3 (GA3 0 mg/l; GA3 0.5 mg/l; GA3 1 mg/l; GA3 1.5 mg/l) and the immersion of nodes (GA3 0 mg/l; GA3 5 mg/l; GA3 10 mg/l; GA3 15 mg/l) with seven replications. The result showed that addition of 0.5 mg/l GA3 of significantly affected the percent of shoot emergence but no significantly different age of shoot emergence and immersion of nodes of 0 mg/l significantly affected the percent of shoot emergence but no significantly different age of shoot emergence and the interraction that addition of 0.5 mg/l GA3 and immersion of nodes significant affected the percent of shoot emergence on age of shoot emergence but no significantly different.Keywords : rubber, micro shoot, addition of GA3, immersion of nodesThe aim of the research was to know effect of GA3 to rubber plant in micro shoot formation. The research was conducted at the rubber plant microcutting labortory PT Perkebunan Nusantara III Kebun Gunung Pamela, Tebing Tinggi, North Sumatera, Indonesia from April 2015 to Juli 2015. The Completely randomize design was used with two factors,i.e.:the addition of GA3 (GA3 0 mg/l; GA3 0.5 mg/l; GA3 1 mg/l; GA3 1.5 mg/l) and the immersion of nodes (GA3 0 mg/l; GA3 5 mg/l; GA3 10 mg/l; GA3 15 mg/l) with seven replications. The result showed that addition of 0.5 mg/l GA3 of significantly affected the percent of shoot emergence but no significantly different age of shoot emergence and immersion of nodes of 0 mg/l significantly affected the percent of shoot emergence but no significantly different age of shoot emergence and the interraction that addition of 0.5 mg/l GA3 and immersion of nodes significant affected the percent of shoot emergence on age of shoot emergence but no significantly different

    Frame-dragging effects on magnetic fields near a rotating black hole

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    We discuss the role of general relativity frame dragging acting on magnetic field lines near a rotating (Kerr) black hole. Near ergosphere the magnetic structure becomes strongly influenced and magnetic null points can develop. We consider aligned magnetic fields as well as fields inclined with respect to the rotation axis, and the two cases are shown to behave in profoundly different ways. Further, we construct surfaces of equal values of local electric and magnetic intensities, which have not yet been discussed in the full generality of a boosted rotating black hole.Comment: to appear in the proceedings of "The Central Kiloparsec in Galactic Nuclei (AHAR 2011)", Journal of Physics: Conference Series (JPCS), IOP Publishin

    The Sound Emission Board of the KM3NeT Acoustic Positioning System

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    We describe the sound emission board proposed for installation in the acoustic positioning system of the future KM3NeT underwater neutrino telescope. The KM3NeT European consortium aims to build a multi-cubic kilometre underwater neutrino telescope in the deep Mediterranean Sea. In this kind of telescope the mechanical structures holding the optical sensors, which detect the Cherenkov radiation produced by muons emanating from neutrino interactions, are not completely rigid and can move up to dozens of meters in undersea currents. Knowledge of the position of the optical sensors to an accuracy of about 10 cm is needed for adequate muon track reconstruction. A positioning system based on the acoustic triangulation of sound transit time differences between fixed seabed emitters and receiving hydrophones attached to the kilometre-scale vertical flexible structures carrying the optical sensors is being developed. In this paper, we describe the sound emission board developed in the framework of KM3NeT project, which is totally adapted to the chosen FFR SX30 ultrasonic transducer and fulfils the requirements imposed by the collaboration in terms of cost, high reliability, low power consumption, high acoustic emission power for short signals, low intrinsic noise and capacity to use arbitrary signals in emission mode.Comment: 9 pages, 4 figure

    High-Resolution, Wide-Field Imaging of the Galactic Center Region at 330 MHz

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    We present a wide field, sub-arcminute resolution VLA image of the Galactic Center region at 330 MHz. With a resolution of ~ 7" X 12" and an RMS noise of 1.6 mJy/beam, this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity has more than tripled the census of small diameter sources in the region, has resulted in the detection of two new Non Thermal Filaments (NTFs), 18 NTF candidates, 30 pulsar candidates, reveals previously known extended sources in greater detail, and has resulted in the first detection of Sagittarius A* in this frequency range. A version of this paper containing full resolution images may be found at http://lwa.nrl.navy.mil/nord/AAAB.pdf.Comment: Astronomical Journal, Accepted 62 Pages, 21 Figure
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