Application of Transmitted Kikuchi Diffraction in Studying Nano-oxide and Ultrafine Metallic Grains

Abbasi, Majid,Kim, Dong-Ik,Guim, Hwan-Uk,Hosseini, Morteza,Danesh-Manesh, Habib,Abbasi, Mehrdad AMERICAN CHEMICAL SOCIETY 2015 ACS NANO Vol.9 No.11

EBSD and reconstruction of pre-transformation microstructures, examples and complexities in steels

Abbasi, M.,Kim, D.I.,Nelson, T.W.,Abbasi, M. Elsevier 2014 Materials characterization Vol.95 No.-

Electron backscattered diffraction has provided a quantitative tool to study micro/nano-structures in large scales. A recent application of electron backscattered diffraction is the reconstruction of pre-transformed phases in polymorphic systems, especially when there is no retained pre-transformed phase at room temperature. This capability has been demonstrated by various researchers utilizing different approaches towards grain structure and orientation recovery. However, parameters affecting reconstruction have not been investigated systematically. Factors such as post-transformed microstructures (morphology and crystallography), lattice strain (deformation), pattern and sample quality are among the affecting factors. Two-dimensional datasets of different steels have been reconstructed along with a limited 3-dimensional dataset in the current paper. Preliminary results intended for large-scale automatic reconstructions have been presented. They indicate that the successfulness of reconstruction is strongly dependent on the post-transformed microstructure. Factors such as morphology, grain size, variant selection, and deformation play roles. Few examples of reconstruction complexity at prior austenite boundaries leading to uncertain results are presented. Lastly, reconstructions are discussed in terms of meaningfulness and if they correctly represent pre-transformed grains and orientations.

Thin film graphene oxide membrane: Challenges and gas separation potential

Fateme Abbasi,Javad Karimi-Sabet,Cyrus Ghotbi,Zeinab Abbasi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5

Graphene oxide membranes were prepared by vacuum and pressurized ultrafiltration methods on the 12% modified Polyacrylonitrile (12mPAN) substrate to specify challenges, salient features, future directions, and potential of GO membrane for separation fields using characterization techniques and gas separation test (studied gases are CO2, He and N2), which is an efficient tool for better understanding of GO membrane behavior. GO membrane structure was examined over a wide range of parameters, such as pore size range of substrate and its surface properties, pH of GO dispersion, GO content, synthesis pressure, operating pressure and temperature. The results show that the GO content does not hold a linear relationship with the permeance and selectivity. Film thickness, aggregates, synthesis pressure defects and interlayer spacing have significant effects on the gas separation performance of GO membranes which originate from the synthesis method and its conditions.

Application of the GTN model to predict the forming limit diagram of IF-Steel

Mahmoud Abbasi,Mohammad A. Shafaat,Mostafa Ketabch,Davoud F. Haghshenas,Mohammad Abbasi 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2

Forming limit diagrams (FLDs) are extensively used in industries, particularly the auto industry. The establishment of these diagrams using a predictive approach can lead to reduction in both cost and time. In the present work, Gurson-Tvergaard-Needleman (GTN), a porosity-based model, was used to predict the FLD of an interstitial-free steel via finite element simulation. Optimum values of the GTN model were obtained by applying a response surface methodology (RSM) based on central composite design. Results show that RSM is a good method for an appropriate determination of the GTN model parameters, such as initial void volume fraction, effective void volume fraction, critical void volume fraction, and final void volume fraction. Furthermore, the experimental FLD of the specimen steel was considerably predicted using the obtained GTN model parameters.

Search for EeV protons of galactic origin

Abbasi, R.U.,Abe, M.,Abu-Zayyad, T.,Allen, M.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Fujii, T.,Fukushima, M.,Goto, T.,Hanlon, W.,Haya North-Holland 2017 Astroparticle physics Vol.86 No.-

<P>Cosmic rays in the energy range 10(18.0)-10(18.5) eV are thought to have a light, probably protonic, composition. To study their origin one can search for anisotropy in their arrival directions. Extragalactic cosmic rays should be isotropic, but galactic cosmic rays of this type should be seen mostly along the galactic plane, and there should be a shortage of events coming from directions near the galactic anticenter. This is due to the fact that, under the influence of the galactic magnetic field, the transition from ballistic to diffusive behavior is well advanced, and this qualitative picture persists over the whole energy range. Guided by models of the galactic magnetic field that indicate that the enhancement along the galactic plane should have a standard deviation of about 20 degrees in galactic latitude, and the deficit in the galactic anticenter direction should have a standard deviation of about 50 degrees in galactic longitude, we use the data of the Telescope Array surface detector in 10(18.0) to 10(18.5) eV energy range to search for these effects. The data are isotropic. Neither an enhancement along the galactic plane nor a deficit in the galactic anticenter direction is found. Using these data we place an upper limit on the fraction of EeV cosmic rays of galactic origin at 1.3% at 95% confidence level. Published by Elsevier B.V.</P>

First upper limits on the radar cross section of cosmic-ray induced extensive air showers

Abbasi, R.U.,Abe, M.,Abou Bakr Othman, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Besson, D.,Blake, S.A.,Byrne, M.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chib North-Holland 2017 Astroparticle physics Vol.87 No.-

<P>TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (similar to 10 mu s) and exhibit rapidly changing frequency, with rates on the order 1 MHz/mu s. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector. (C) 2016 Elsevier B.V. All rights reserved.</P>

ON EIGENSHARPNESS AND ALMOST EIGENSHARPNESS OF LEXICOGRAPHIC PRODUCTS OF SOME GRAPHS

Abbasi, Ahmad,Taleshani, Mona Gholamnia Korean Mathematical Society 2022 대한수학회보 Vol.59 No.3

The minimum number of complete bipartite subgraphs needed to partition the edges of a graph G is denoted by b(G). A known lower bound on b(G) states that b(G) ≥ max{p(G), q(G)}, where p(G) and q(G) are the numbers of positive and negative eigenvalues of the adjacency matrix of G, respectively. When equality is attained, G is said to be eigensharp and when b(G) = max{p(G), q(G)} + 1, G is called an almost eigensharp graph. In this paper, we investigate the eigensharpness and almost eigensharpness of lexicographic products of some graphs.

Diagnosis of Malignant Biliary Strictures: Conventional or Negative Pressure Brush Cytology?

Abbasi, Mohammad Reza,Mirsaeed, Seyedeh Masoumeh Ghazi,Alizadeh, Amir Houshang Mohammad Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.10

Background/Objective: The aim of this study was to perform a comparative evaluation of the yields of conventional brush cytology and brush cytology with negative pressure in the diagnosis of malignant biliary strictures. Methods: A total of 132 consecutive patients undergoing endoscopic were identified. Of these, 88.0 had brush cytology after ERCP and 44 were Brush cytology with negative pressure. Retrograde cholangiopancreatography (ERCP) including brush cytology and brush cytology with negative pressure in patients with biliary strictures between 2012-2015. Endoscopic retrograde cholangiography was performed with a standard videoduodenoscope Olympus TFJ 160-R (Olympus, Hamburg, Germany) and brush cytology with a Cook medical Double Lumen Biliary BrushTM (Cytology). Means and standard frequencies were used to calculate variables. Results: Positive results for malignancy were obtained in 22 of 88 patients (25%) by brush cytology and 31 of 44 patients (70.4 %) by brush cytology with negative pressure. Conclusions: Sensitivity of cytology sampling could be maximized by negative pressure during ERCP.

A NORTHERN SKY SURVEY FOR POINT-LIKE SOURCES OF EeV NEUTRAL PARTICLES WITH THE TELESCOPE ARRAY EXPERIMENT

Abbasi, R. U.,Abe, M.,Zayyad, T. Abu-,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J. W.,Bergman, D. R.,Blake, S. A.,Cady, R.,Chae, M. J.,Cheon, B. G.,Chiba, J.,Chikawa, M.,Cho, W. R.,Fujii, IOP Publishing 2015 The Astrophysical journal Vol.804 No.2

<P>We report on the search for steady point-like sources of neutral particles around 10(18) eV between 2008 and 2013 May with the scintillator SD of the Telescope Array experiment. We found overall no significant point-like excess above 0.5 EeV in the northern sky. Subsequently, we also searched for coincidence with the Fermi bright Galactic sources. No significant coincidence was found within the statistical uncertainty. Hence, we set an upper limit on the neutron flux that corresponds to an averaged flux of 0.07 km(-2) yr(-1) for E > 1 EeV in the northern sky at the 95% confidence level. This is the most stringent flux upper limit in a northern sky survey assuming point-like sources. The upper limit at the 95% confidence level on the neutron flux from Cygnus X-3 is also set to 0.2 km(-2) yr(-1) for E > 0.5 EeV. This is an order of magnitude lower than previous flux measurements.</P>

The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array

Abbasi, R.U.,Abe, M.,Abu-Zayyad, T.,Allen, M.G.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Cho, W.R.,Fujii, T.,Fu North-Holland ; Elsevier Science Ltd 2015 Astroparticle physics Vol.68 No.-

The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.