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2021 ◽  
Vol 257 (2) ◽  
pp. 61
Author(s):  
Satoshi Yamada ◽  
Yoshihiro Ueda ◽  
Atsushi Tanimoto ◽  
Masatoshi Imanishi ◽  
Yoshiki Toba ◽  
...  

Abstract We perform a systematic X-ray spectroscopic analysis of 57 local luminous and ultraluminous infrared galaxy systems (containing 84 individual galaxies) observed with the Nuclear Spectroscopic Telescope Array and/or Swift/BAT. Combining soft X-ray data obtained with Chandra, XMM-Newton, Suzaku, and/or Swift/XRT, we identify 40 hard (>10 keV) X-ray–detected active galactic nuclei (AGNs) and constrain their torus parameters with the X-ray clumpy torus model XCLUMPY. Among the AGNs at z < 0.03, for which sample biases are minimized, the fraction of Compton-thick (N H ≥ 1024 cm−2) AGNs reaches 64 − 15 + 14 % (6/9 sources) in late mergers, while it is 24 − 10 + 12 % (3/14 sources) in early mergers, consistent with the tendency reported by Ricci et al. We find that the bolometric AGN luminosities derived from the infrared data increase but the X-ray to bolometric luminosity ratios decrease with merger stage. The X-ray-weak AGNs in late mergers ubiquitously show massive outflows at subparsec to kiloparsec scales. Among them, the most luminous AGNs (L bol,AGN ∼ 1046 erg s−1) have relatively small column densities of ≲1023 cm−2 and almost super-Eddington ratios (λ Edd ∼ 1.0). Their torus covering factors (C T (22) ∼ 0.6) are larger than those of Swift/BAT-selected AGNs with similarly high Eddington ratios. These results suggest a scenario where, in the final stage of mergers, multiphase strong outflows are produced due to chaotic quasi-spherical inflows, and the AGN becomes extremely X-ray weak and deeply buried due to obscuration by inflowing and/or outflowing material.


2021 ◽  
Author(s):  
Mazda Biglari ◽  
Hui Liu ◽  
Ali Elkamel ◽  
Ali Lohi

Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics) approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predict the hydrodynamics of the small column. The outcomes of this research present both the scaling law with the lower computational cost and the CFD modeling as a more robust method to suit various needs for the design of fluidized-bed gasifiers.


2021 ◽  
Author(s):  
Mazda Biglari ◽  
Hui Liu ◽  
Ali Elkamel ◽  
Ali Lohi

Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics) approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predict the hydrodynamics of the small column. The outcomes of this research present both the scaling law with the lower computational cost and the CFD modeling as a more robust method to suit various needs for the design of fluidized-bed gasifiers.


2021 ◽  
Author(s):  
Margaret Stevenson ◽  
Thomas Oudega ◽  
Gerhard Lindner ◽  
Andreas Scheidl ◽  
Alexander Eder ◽  
...  

&lt;p&gt;Upscaling groundwater transport from the column scale to the field scale is relevant because field tests with various tracers are often too expensive or not permissible, due to public health or environmental concerns.&amp;#160; Therefore, when testing chemical or pathogenic tracers, work is often done using small scale columns in the laboratory and results are extrapolated to the field. Several studies compare tracer transport in small-scale columns to tests in the field, but there is yet to be a study that compares groundwater transport using a meso-scale as well. Within a framework of upscaling, three scales are considered: small laboratory columns (0.1 m scale), a large intact core (1 m scale), and a real-world gravel aquifer (10 m scale).&amp;#160; The small column is filled with gravel material taken from boreholes at the field site, which is close to Vienna, Austria.&amp;#160; The meso-scale consists of an undisturbed gravel column, which was taken from a gravel pit near Neuhofen an der Ybbs, Austria. It was found that scale effects observed may be due to heterogeneity at the macropore scale versus preferential flowpaths at the meso-scale and field scale. Additionally, differences may be observed due to the small columns being repacked with aquifer material and the large column and field site being &amp;#8220;undisturbed&amp;#8221;.&amp;#160; The meso-scale column allows us to gain insight into the upscaling processes by incorporating an in-between step when comparing groundwater transport at the column to the field scale.&lt;/p&gt;


Author(s):  
Mohamed Nagar S ◽  
◽  
F A El-Sayed ◽  
W M Morsy ◽  
◽  
...  

Detailed studies of uranium heap leaching from different uranium mineralization resources situated in Eastern Desert of Egypt were investigated using sulfuric acid via batch experiments, followed by using the obtained optimum condition on bench scale leaching tests using small column. The previous optimum parameters were implemented on another large scale column in order to make more condition control and evaluate the time and reagents needed while transferring from small to large scale. The obtained data shows that leaching efficiency of GII mineralization attained about 78.3% with consumed acid amount about 34 kg/ton in a 44 days as leaching time, on the other hand, leaching efficiency of uranium from El-Missikat mineralization higher than GII mineralization and attained about 86.6% and the consumed as lower than G-II about 28kg/ton in a 40 days leaching time. Kinetics reaction models of column tests have been investigated to optimize the column leaching behavior. Based on the leaching results of the two mineralized occurrences, the rate of the uranium dissolution is controlled by both the chemical reaction and the diffusion reaction but diffusion reaction control was more predominate than a chemical reaction.


2019 ◽  
Vol 1598 ◽  
pp. 154-162 ◽  
Author(s):  
Krystian Baran ◽  
Wojciech Kazimierz Marek ◽  
Wojciech Piątkowski ◽  
Dorota Antos
Keyword(s):  

2018 ◽  
Vol 19 (2) ◽  
pp. 964-972 ◽  
Author(s):  
Anita Leovac Maćerak ◽  
Ivana Ivančev-Tumbas ◽  
Hilmar Börnick ◽  
Gordana Ilić ◽  
Marijana Kragulj Isakovski ◽  
...  
Keyword(s):  

2017 ◽  
Vol 51 (5) ◽  
pp. 543
Author(s):  
Nguyen Thanh Trung ◽  
Pham Thi Tam ◽  
Ta Thi Thu Thuy ◽  
Chunyin Gu ◽  
Zhenyu Zhang

RAVE (Regulator of the H+-ATPase of the Vacuolar and Endosomal membranes) is an            essential factor of assembly and reversible disassembly of V-ATPase. RAVE complex has three subunits, which are Rav1p, Rav2p and Skp1p. There are few studies on RAVE so it is very             important to study structure of RAVE complex to understand more about the regulation of the assembly and reassembly at V-ATPase. In this study the RAVE complex was purified by affinity purification by fussing FLAG tag to subunit Rav1p or Rav2p. Experimental process: yeast cells were incubated in 8 L YEPD medium at 30 oC, 200 rpm (OD600nm around of 3). Furthermore                   harvested cells were broken by a French pressure cell disruptor at 25,000 p.s.i in TBSE (50 mM Tris/Cl, 150 mM NaCl, 1 mM EDTA, pH 7.4) with 1 mm PMSF. The cell lysate was centrifuged at 20,000 xg for 20 minutes at 4 oC. Then, the supernatant, was achieved by centrifugation, and loaded onto a small column contained 1 ml of anti-FLAG M2 gel. After washing anti-FLAG column with TBSE, RAVE complex was eluted with TBSE containing 100 µg/ml FLAG               peptides. The results showed RAVE complex purification from strain with FLAG tag fused in                 C-terminus of Rav2 is better than RAVE complex purification from the yeast strain S. cerevisiae with FLAG tag fused in N-terminus of Rav1 or C-terminus of Rav1.


2015 ◽  
Vol 50 (2) ◽  
pp. 143-152 ◽  
Author(s):  
D Talukder ◽  
AB MH Haque ◽  
S Zaman ◽  
MS Islam ◽  
MN Islam ◽  
...  

An experiment was carried out to investigate the efficacy of contact toxicity of different fractions of petroleum ether extract of Zinziber cassumunar Roxb. rhizome against Tribolium castaneum. Seventy-eight different fractions of petroleum ether extract were obtained from column chromatography. Elutes having the similar TLC behavior were combined in eight fractions and were named as: MN-1, MN-2, MN-3, MN-4, MN-5, MN-6, MN-7 and MN-8. Four separate fractions were collected from the MN-1 fraction by preparative thin layer chromatography. These four parts were washed with petroleum ether, chloroform, ethyl acetate and methanol. Thereafter, these were separated by small column and designated as: M1N1, M1N2, M1N3, M1N4, M2N1, M2N2, M2N3, M2N4, M3N1, M3N2, M3N3, M3N4, M4N1 and M4N2. Fractions of M1N2, M2N2, M3N2 and M4N2 were found to be the most effective against the beetle T. castaneum after 24, 48 and 72 hours. However, some fractions exhibited the moderate effect and other fractions did not work against the beetle.Bangladesh J. Sci. Ind. Res. 50(2), 143-152, 2015


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