589 research outputs found

    Probing the Circumnuclear Stellar Populations of Starburst Galaxies in the Near-infrared

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    We employ the NASA Infrared Telescope Facility's near-infrared spectrograph SpeX at 0.8-2.4ÎŒ\mum to investigate the spatial distribution of the stellar populations (SPs) in four well known Starburst galaxies: NGC34, NGC1614, NGC3310 and NGC7714. We use the STARLIGHT code updated with the synthetic simple stellar populations models computed by Maraston (2005, M05). Our main results are that the NIR light in the nuclear surroundings of the galaxies is dominated by young/intermediate age SPs (t≀2×109t \leq 2\times10^9yr), summing from ∌\sim40\% up to 100\% of the light contribution. In the nuclear aperture of two sources (NGC1614 and NGC3310) we detected a predominant old SP component (t>2×109t > 2\times10^9yr), while for NGC34 and NGC7714 the younger component prevails. Furthermore, we found evidence of a circumnuclear star formation ring-like structure and a secondary nucleus in NGC1614, in agreement with previous studies. We also suggest that the merger/interaction experienced by three of the galaxies studied, NGC1614, NGC3310 and NGC7714 can explain the lower metallicity values derived for the young SP component of these sources. In this scenario the fresh unprocessed metal poorer gas from the destroyed/interacting companion galaxy is driven to the centre of the galaxies and mixed with the central region gas, before star formation takes place. In order to deepen our analysis, we performed the same procedure of SP synthesis using Maraston (2011, M11) EPS models. Our results show that the newer and higher resolution M11 models tend to enhance the old/intermediate age SP contribution over the younger ages

    Kajian Algoritma Pengolahan Citra Aqua/ Terra Modis Untuk Identifikasi Dan Monitoring Tumpahan Minyak (Oil Spill) Di Laut Timor Tahun 2009

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    Penelitian ini bertujuan untuk mengetahui algoritma yang lebih optimal dalam pengolahan citra MODIS, khususnya untuk digunakan dalam proses identifikasi dan monitoring tumpahan minyak di perairan laut. Selain itu penelitian ini juga bertujuan untuk mengetahui bagaimana pola persebaran tumpahan minyak di perairan Laut Timor akibat ledakan anjungan minyak Montara yang terjadi tahun 2009. Berdasarkan uji akurasi yang dilakukan dapat diketahui bahwa metode klasifikasi citra Maximum Likelihood, gabungan PC13 dan NDVI memiliki nilai akurasi paling baik untuk identifikasi tumpahan minyak di perairan Laut Timor. Berdasarkan hasil pengolahan dan analisis yang dilakukan dapat diketahui jika pola persebaran tumpahan minyak di perairan Laut Timor yang berasal dari anjungan minyak Montara cenderung menyebar mengikuti arah pergerakan angin. Selain itu dapat diketahui juga bahwa total luas perairan laut yang tercemar oleh tumpahan minyak dari tanggal 30 Agustus 2009 sampai 2 November 2009 kurang lebih seluas 22.673,10 km2, dimana seluas 4.285,01 km2 terdapat di perairan laut Indonesia

    Implementation of Lean Warehouse to Minimize Wastes in Finished Goods Warehouse of PT Charoen Pokphand Indonesia Semarang

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    PT. Charoen Pokphand Indonesia Semarang is one of the largest poultry feed companies in Indonesia. To store the finished products that are ready to be distributed, it needs a finished goods warehouse. To minimize the wastes that occur in the process of warehousing the finished goods, the implementation of lean warehouse is required. The core process of finished goods warehouse is the process of putting bag that has been through the process of pallets packing, and then transporting the pallets contained bags of feed at finished goods warehouses and the process of unloading food from the finished goods warehouse to the distribution truck. With the implementation of the lean warehouse, we can know whether the activities are value added or not, to be identified later which type of waste happened. Opinions of stakeholders regarding the waste that must be eliminated first need to be determined by questionnaires. Based on the results of the questionnaires, three top wastes are selected to be identified the cause by using fishbone diagram. They can be repaired by using the implementation of 5S, namely Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. Defect waste can be minimized by selecting pallet, putting sack correctly, forklift line clearance, applying working procedures, and creating cleaning schedule. Next, overprocessing waste is minimized by removing unnecessary items, putting based on the date of manufacture, and manufacture of feed plan. Inventory waste is minimized by removing junks, putting feed based on the expired date, and cleaning the bar

    Analyzing a Bose polaron across resonant interactions

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    Recently, two independent experiments reported the observation of long-lived polarons in a Bose-Einstein condensate, providing an excellent setting to study the generic scenario of a mobile impurity interacting with a quantum reservoir. Here, we expand the experimental analysis by disentangling the effects of trap inhomogeneities and the many-body continuum in one of these experiments. This makes it possible to extract the energy of the polaron at a well-defined density as a function of the interaction strength. Comparisons with quantum Monte-Carlo as well as diagrammatic calculations show good agreement, and provide a more detailed picture of the polaron properties at stronger interactions than previously possible. Moreover, we develop a semi-classical theory for the motional dynamics and three-body loss of the polarons, which partly explains a previously unresolved discrepancy between theory and experimental observations for repulsive interactions. Finally, we utilize quantum Monte-Carlo calculations to demonstrate that the findings reported in the two experiments are consistent with each other

    Catalyzation of supersolidity in binary dipolar condensates

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    Breakthrough experiments have newly explored the fascinating physics of dipolar quantum droplets and supersolids. The recent realization of dipolar mixtures opens further intriguing possibilities. We show that under rather general conditions, the presence of a second component catalyzes droplet nucleation and supersolidity in an otherwise unmodulated condensate. Droplet catalyzation in miscible mixtures, which may occur even for a surprisingly small impurity doping, results from a local roton instability triggered by the doping-dependent modification of the effective dipolar strength. The catalyzation mechanism may trigger the formation of a two-fluid supersolid, characterized by a generally different superfluid fraction of each component, which opens intriguing possibilities for the future study of spin physics in dipolar supersolids

    Multicolor photometry of ten Seyfert 1 galaxies

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    We present BVI photometry of ten Seyfert 1 galaxies and narrow band H-alpha images for six of these objects as well. The results indicate that the luminosity sample distribution has an amplitude of almost 4 magnitudes with an average of M_B=-20.7. The observed morphologies are confined to early type galaxies. A barred structure is found in only 2 objects. Despite that early morphological types are dominant in this sample, integrated (B-V) colors are very blue. For instance, the SO galaxies show, on average, a (B-V)=0.78. This effect seems to be caused by the luminosity contribution of the active nucleus and/or the disk to the total luminosity of the galaxy. In the B band, the contribution of the active galactic nucleus to the total luminosity of the galaxy varies from 3% to almost 60% and the bulge to disk luminosity ratio (L_bulge/L_disk) ranges from 0.6 to 22. Signs of tidal interactions seems to be a common characteristic since they are observed in 6 of the objects and one of them seems to be located in a poor cluster not yet identified in the literature. H_alpha extended emission is rare, with only 1 galaxy showing clear evidence of it. Luminosity profile decomposition shows that the model Gauss + bulge + disk properly reproduces the surface brightness of the galaxies. However, in order to account for the luminosity profile, most of the disk galaxies needs the inner truncated exponential form with a central cutoff radius ranging from 3 to 10 kpc. This is interpreted in terms of reddened regions that are well identified in the B-V color maps. These regions present very similar colors among them, with (B-V)~1.2. This fact could be associated to the presence of dust confined in the inner regions of the galaxies.Comment: 14 pages, 25 figures. Accepted to Astronomy & Astrophysic

    Alternating-domain supersolids in binary dipolar condensates

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    Two-component dipolar condensates are now experimentally producible, and we theoretically investigate the nature of supersolidity in this system. We predict the existence of a binary supersolid state in which the two components form a series of alternating domains, producing an immiscible double supersolid. Remarkably, we find that a dipolar component can even induce supersolidity in a nondipolar component. In stark contrast to single-component dipolar supersolids, alternating-domain supersolids do not require quantum stabilization, and the number of crystal sites is not strictly limited by the condensate populations, with the density hence being substantially lower. Our results are applicable to a wide range of dipole moment combinations, marking an important step towards long-lived bulk-supersolidity

    Abrasion-Corrosion of Ferritic Stainless Steel

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    Several studies have measured abrasion-corrosion for biomaterials, alloys, and stainless steel. Despite the considerable effort to understand the synergy between abrasion-corrosion resistance of stainless steel, they have mainly focused on more traditional materials, such as AISI 304 and AISI 316 stainless steel, and, more recently, on AISI 2205 duplex stainless steel. Little progress has been made to understand this phenomenon for cost-effective ferritic stainless steel. In this chapter, we first show the great potential of the use of ferritic stainless steel in the sugar cane biofuel industry. The influence of their crystallographic texture on the corrosion resistance of 16% Cr ferritic stainless steel (both niobium-stabilized and non-stabilized) is presented and discussed. We also analyses the microabrasion-corrosion performance of ferritic stainless steel with different chemical compositions (11%wt Cr with and without Ti stabilization; 16%wt Cr with and without Nb stabilization) and, for comparative purposes, austenitic stainless steel (18%wt Cr-8%wt Ni) and carbon steel (0.2%wt C). For all materials tested, microabrasion wear coefficients were higher (4x) than those measured under abrasion-corrosion conditions. Friction coefficients could also be measured by a 3D load cell strategically positioned in the specially developed microabrasion-corrosion device, showing a strong reduction (2x) in friction coefficient under abrasion-corrosion conditions when compared with solely abrasion conditions

    Infrared FeII Emission in Narrow-Line Seyfert 1 Galaxies

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    We obtained 0.8-2.4 micron spectra at a resolution of 320 km/s of four narrow-line Seyfert 1 galaxies in order to study the near-infrared properties of these objects. We focus on the analysis of the FeII emission in that region and the kinematics of the low-ionization broad lines. We found that the 1 micron FeII lines (9997 A, 10501 A, 10863 A and 11126 A) are the strongest FeII lines in the observed interval. For the first time, primary cascade lines of FeII arising from the decay of upper levels pumped by Ly-alpha fluorescence are resolved and identified in active galactic nuclei. Excitation mechanisms leading to the emission of the 1 micron FeII features are discussed. A combination of Ly-alpha fluorescence and collisional excitation are found to be the main contributors. The flux ratio between near-IR FeII lines varies from object to object, in contrast to what is observed in the optical region. A good correlation between the 1 micron and optical FeII emission is found. This suggests that the upper z4Fo and z4Do levels from which the bulk of the optical lines descend are mainly populated by the transitions leading to the 1 micron lines. The width and profile shape of FeII 11127, CaII 8642 and OI 8446 are very similar but significantly narrower than Pa-beta, giving strong observational support to the hypothesis that the region where FeII, CaII and OI are produced are co-spatial, interrelated kinematically and most probably located in the outermost portion of the BLR.Comment: Accepted for publication in ApJ - 35 page
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