589 research outputs found
Probing the Circumnuclear Stellar Populations of Starburst Galaxies in the Near-infrared
We employ the NASA Infrared Telescope Facility's near-infrared spectrograph
SpeX at 0.8-2.4m 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 (yr), summing from
40\% up to 100\% of the light contribution. In the nuclear aperture of
two sources (NGC1614 and NGC3310) we detected a predominant old SP component
(yr), 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
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
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
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
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
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
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
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
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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