The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
D Santana - One of the best experts on this subject based on the ideXlab platform.
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estimation and experimental validation of the Circulation Time in a 2d gas solid fluidized beds
Powder Technology, 2013Co-Authors: S Sanchezdelgado, C Marugancruz, A Soriaverdugo, D SantanaAbstract:Abstract The Circulation Time is defined as the Time required for a group of particles to reach the freeboard from the bottom of a fluidized bed and return to their original height. This work presents an estimation and validation of the Circulation Time in a 2D gas–solid bubbling fluidized bed under different operating conditions. The Circulation Time is based on the concept of the turnover Time, which was previously defined by Geldart [1] as the Time required to turn the bed over once. The equation tc,est = 2Ah′/Qb is used to calculate the Circulation Time, where A is the cross-section of the fluidized bed, h′ is the effective fluidized bed height and Qb is the visible bubble flow. The estimation of the Circulation Time is based on the operating parameters and the bubble phase properties, including the bubble diameter, bubble velocity and bed expansion. The experiments for the validation were carried out in a 2D bubbling fluidized bed. The dense phase velocity was measured with a high-speed camera and non intrusive techniques such as particle image velocimetry (PIV) and digital image analysis (DIA), and the experimental Circulation Time was calculated for all cases. The agreement between the theoretical and experimental Circulation Times was satisfactory, and hence, the proposed estimation can be used to reliably predict the Circulation Time.
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Estimation and experimental validation of the Circulation Time in a 2D gas–solid fluidized beds
Powder Technology, 2013Co-Authors: S. Sánchez-delgado, C. Marugán-cruz, Antonio Soria-verdugo, D SantanaAbstract:Abstract The Circulation Time is defined as the Time required for a group of particles to reach the freeboard from the bottom of a fluidized bed and return to their original height. This work presents an estimation and validation of the Circulation Time in a 2D gas–solid bubbling fluidized bed under different operating conditions. The Circulation Time is based on the concept of the turnover Time, which was previously defined by Geldart [1] as the Time required to turn the bed over once. The equation tc,est = 2Ah′/Qb is used to calculate the Circulation Time, where A is the cross-section of the fluidized bed, h′ is the effective fluidized bed height and Qb is the visible bubble flow. The estimation of the Circulation Time is based on the operating parameters and the bubble phase properties, including the bubble diameter, bubble velocity and bed expansion. The experiments for the validation were carried out in a 2D bubbling fluidized bed. The dense phase velocity was measured with a high-speed camera and non intrusive techniques such as particle image velocimetry (PIV) and digital image analysis (DIA), and the experimental Circulation Time was calculated for all cases. The agreement between the theoretical and experimental Circulation Times was satisfactory, and hence, the proposed estimation can be used to reliably predict the Circulation Time.
Axel Jessner - One of the best experts on this subject based on the ideXlab platform.
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single pulse analysis of psr b1133 16 at 8 35 ghz and carousel Circulation Time
Monthly Notices of the Royal Astronomical Society, 2012Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt has been made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-m Effelsberg radio telescope. The high-resolution (60 μs) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both longitude- and harmonic-resolved fluctuation spectral analysis. We identified the low-frequency feature associated with an amplitude modulation at , which can be interpreted as the Circulation Time P4≃ 30 P1 of the underlying subbeam carousel model. Despite the erratic nature of this pulsar, we also found evidence of periodic pseudo-nulls with P4= 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
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Single pulse analysis of PSR B1133+16 at 8.35 GHz and carousel Circulation Time
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt was made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-meter Effelsberg radio-telescope. The high resolution (60 micro-seconds) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both the longitude- and the harmonic-resolved fluctuation spectral analysis. We identified the low frequency feature associated with an amplitude modulation at f4 ~ 0.033 P1^(-1), which can be interpreted as the Circulation Time P4 ~ 30 P1 of the underlying subbeam carousel model. Despite an erratic nature of this pulsar, we also found an evidence of periodic pseudo-nulls with P4 = 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
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single pulse analysis of psr b1133 16 at 8 35 ghz and carousel Circulation Time
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt was made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-meter Effelsberg radio-telescope. The high resolution (60 micro-seconds) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both the longitude- and the harmonic-resolved fluctuation spectral analysis. We identified the low frequency feature associated with an amplitude modulation at f4 ~ 0.033 P1^(-1), which can be interpreted as the Circulation Time P4 ~ 30 P1 of the underlying subbeam carousel model. Despite an erratic nature of this pulsar, we also found an evidence of periodic pseudo-nulls with P4 = 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
Marco Salvatore - One of the best experts on this subject based on the ideXlab platform.
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multiple sclerosis cerebral Circulation Time
Radiology, 2012Co-Authors: M Mancini, Elena Salvatore, Vincenzo Morra, Orlando Di Donato, Valentina Maglio, Roberta Lanzillo, Raffaele Liuzzi, Arturo Brunetti, Vittorio Iaccarino, Marco SalvatoreAbstract:Cerebral Circulation Time is substantially prolonged in patients with multiple sclerosis compared with that in control subjects.
Sneha Honnappa - One of the best experts on this subject based on the ideXlab platform.
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single pulse analysis of psr b1133 16 at 8 35 ghz and carousel Circulation Time
Monthly Notices of the Royal Astronomical Society, 2012Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt has been made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-m Effelsberg radio telescope. The high-resolution (60 μs) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both longitude- and harmonic-resolved fluctuation spectral analysis. We identified the low-frequency feature associated with an amplitude modulation at , which can be interpreted as the Circulation Time P4≃ 30 P1 of the underlying subbeam carousel model. Despite the erratic nature of this pulsar, we also found evidence of periodic pseudo-nulls with P4= 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
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Single pulse analysis of PSR B1133+16 at 8.35 GHz and carousel Circulation Time
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt was made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-meter Effelsberg radio-telescope. The high resolution (60 micro-seconds) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both the longitude- and the harmonic-resolved fluctuation spectral analysis. We identified the low frequency feature associated with an amplitude modulation at f4 ~ 0.033 P1^(-1), which can be interpreted as the Circulation Time P4 ~ 30 P1 of the underlying subbeam carousel model. Despite an erratic nature of this pulsar, we also found an evidence of periodic pseudo-nulls with P4 = 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
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single pulse analysis of psr b1133 16 at 8 35 ghz and carousel Circulation Time
arXiv: Solar and Stellar Astrophysics, 2011Co-Authors: Sneha Honnappa, Wojciech Lewandowski, Jaroslaw Kijak, Avinash A. Deshpande, Olaf Maron, Axel JessnerAbstract:A successful attempt was made to analyse about 6000 single pulses of PSR B1133+16 obtained with the 100-meter Effelsberg radio-telescope. The high resolution (60 micro-seconds) data were taken at a frequency of 8.35 GHz with a bandwidth of 1.1 GHz. In order to examine the pulse-to-pulse intensity modulations, we performed both the longitude- and the harmonic-resolved fluctuation spectral analysis. We identified the low frequency feature associated with an amplitude modulation at f4 ~ 0.033 P1^(-1), which can be interpreted as the Circulation Time P4 ~ 30 P1 of the underlying subbeam carousel model. Despite an erratic nature of this pulsar, we also found an evidence of periodic pseudo-nulls with P4 = 28.44 P1. This is exactly the value at which Herfindal & Rankin found periodic pseudo-nulls in their 327 MHz data. We thus believe that this is the actual carousel Circulation Time in PSR B1133+16, particularly during orderly Circulation.
Xingquan Zhao - One of the best experts on this subject based on the ideXlab platform.
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Difference in Cerebral Circulation Time between Subtypes of Moyamoya Disease and Moyamoya Syndrome
Scientific Reports, 2017Co-Authors: Kaijiang Kang, Jingjing Lu, Dong Zhang, Youxiang Li, Dandan Wang, Bohong Li, Yi Ju, Xingquan ZhaoAbstract:In this study, we evaluated the differences in hemodynamics between hemorrhagic and non-hemorrhagic moyamoya disease (MMD) and moyamoya syndrome (MMS) by measuring cerebral Circulation Time (CCT). This case-control study included 136 patients with MMD or MMS diagnosed between April 2015 and July 2016 at Beijing Tian Tan Hospital. Each hemisphere was analyzed separately. The difference in clinical, radiological characteristics and CCT between subtypes of MMD and MMS were analyzed statistically. The results showed that total CCT between hemorrhagic and non-hemorrhagic sides was not statistically different (16.55 s vs. 16.06 s, P = 0.562). The cerebral filling Circulation Time (CFCT) of hemorrhagic sides was significantly shorter than that of non-hemorrhagic sides (4.52 s vs. 5.41 s, P
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difference in cerebral Circulation Time between subtypes of moyamoya disease and moyamoya syndrome
Scientific Reports, 2017Co-Authors: Kaijiang Kang, Jingjing Lu, Dong Zhang, Youxiang Li, Dandan Wang, Bohong Li, Yi Ju, Xingquan ZhaoAbstract:In this study, we evaluated the differences in hemodynamics between hemorrhagic and non-hemorrhagic moyamoya disease (MMD) and moyamoya syndrome (MMS) by measuring cerebral Circulation Time (CCT). This case-control study included 136 patients with MMD or MMS diagnosed between April 2015 and July 2016 at Beijing Tian Tan Hospital. Each hemisphere was analyzed separately. The difference in clinical, radiological characteristics and CCT between subtypes of MMD and MMS were analyzed statistically. The results showed that total CCT between hemorrhagic and non-hemorrhagic sides was not statistically different (16.55 s vs. 16.06 s, P = 0.562). The cerebral filling Circulation Time (CFCT) of hemorrhagic sides was significantly shorter than that of non-hemorrhagic sides (4.52 s vs. 5.41 s, P < 0.001), and the cerebral venous Circulation Time (CVCT) of hemorrhagic sides was significantly longer than that of non-hemorrhagic sides (12.02 s, vs. 10.64 s, P < 0.001). The ratio of CFCT to CVCT (F-V ratio) was inversely correlated with the possibility of hemorrhagic stroke. Therefore, we conclude that the rapid filling and poor venous drainage of cerebral Circulation are likely risk factors of hemorrhagic stroke secondary to MMD or MMS. The F-V ratio can be used to identify individuals at high risk of hemorrhagic stroke.