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Kolkata, India

Micro hardness of sintered zinc oxide (ZnO) ceramics made from two different particle sizes was measured in a relatively wider range of applied test load (0.2-49N). Experimentally measured apparent hardness data were analyzed to understand the indentation size effect (ISE) in the full range of load. Meyer's law was successfully utilized to describe the ISE behavior though it was unable to generate true hardness data. Load independent true hardness was assessed from the measured diagonal of the indented impression and the test load using the modified PSR model. True hardness numbers determined with this empirical method vary within 1.50-1.83GPa depending on grain size of the sintered products. Indentation fracture toughness was measured with slightly higher test load of 9.8-49N. Nature of crack emanated at the corners of the indent was identified as radial median type. The quantity P/C3/2 was observed to be independent on applied load for all the samples with experimental scatter. Fracture toughness calculated from the length of the indentation induced cracks exhibits dependence on grain size. Maximum fracture toughness of 2.50±0.30MPam1/2 was observed for the ground ZnO sample sintered at 1300°C for 1h duration. © 2015 Elsevier B.V. Source

Mitra J.,VECC | Khan S.A.,VECC | Mukherjee S.,Bose Institute of India | Paul R.,University of Calcutta
Journal of Instrumentation | Year: 2016

The ALICE experiment at the CERN Large Hadron Collider (LHC) is presently going for a major upgrade in order to fully exploit the scientific potential of the upcoming high luminosity run, scheduled to start in the year 2021. The high interaction rate and the large event size will result in an experimental data flow of about 1 TB/s from the detectors, which need to be processed before sending to the online computing system and data storage. This processing is done in a dedicated Common Readout Unit (CRU), proposed for data aggregation, trigger and timing distribution and control moderation. It act as common interface between sub-detector electronic systems, computing system and trigger processors. The interface links include GBT, TTC-PON and PCIe. GBT (Gigabit transceiver) is used for detector data payload transmission and fixed latency path for trigger distribution between CRU and detector readout electronics. TTC-PON (Timing, Trigger and Control via Passive Optical Network) is employed for time multiplex trigger distribution between CRU and Central Trigger Processor (CTP). PCIe (Peripheral Component Interconnect Express) is the high-speed serial computer expansion bus standard for bulk data transport between CRU boards and processors. In this article, we give an overview of CRU architecture in ALICE, discuss the different interfaces, along with the firmware design and implementation of CRU on the LHCb PCIe40 board. © 2016 IOP Publishing Ltd and Sissa Medialab srl. Source

Rashid M.H.,VECC | Mallik C.,VECC
CYCLOTRONS 2010 - 19th International Conference on Cyclotrons and Their Applications | Year: 2010

Magnetic cylindrical lens is used mostly in beam lines to focus and transport low energy beam. It is well known that focusing power of a magnetic solenoid lens depends on the ratio of particle momentum and electric charge. A solenoid rotates also an ion beam while focusing it and the phase space areas of the beam in x- and y-plane get entangled and increased. The paper reported here describes an effort to design a new magnetic einzel lens (MEL) using a pair of Glaser solenoid lens (GSL) in anti-solenoid mode for the first time to get zero rotation of the exit beam. Analytical formulae have been generated to deduce the scalar magnetic potential and field along the central axis of the lens. Thereafter, beam optics and particle tracking is done using the combined field of a pair of GSL's constituting the MEL. The required focusing power of the designed lens is achieved for a beam of given rigidity. Source

Srivastava S.,VECC | Pandit V.S.,VECC
PCaPAC 2012 - 9th International Workshop on Personal Computers and Particle Accelerator Controls | Year: 2012

This paper presents a novel scheme for the direct estimation of a PID (Proportional Integral Derivative) controller parameters (Kp, Ti, Td).The proposal discussed here is only applicable to first and second order stable systems. The formulation begins with system parameter identification (Transfer function of the process), which has been obtained using system identification toolbox of MATLAB. The pole zero cancellation technique is applied to estimate PID controller parameters which inturn results into the matched coefficients of the system parameters to the Controller parameters. An additional tuning parameters a is proposed in our method, which provides an additional flexibility of tuning the response time of the controller without disturbing the controller parameters. The proposed scheme is bench marked using real time case of dc motor speed control. The effectiveness and robustness of the proposed auto tuning algorithm are verified by the simulation results. © 2012 by the respective authors. Source

Singh B.,McMaster University | Abriola D.,International Atomic Energy Agency | Baglin C.,LBNL | Demetriou V.,International Atomic Energy Agency | And 6 more authors.
Nuclear Data Sheets | Year: 2013

The evaluated spectroscopic data are presented for 11 known nuclides of mass 211 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th). The 211Pa nuclide is included here but its identification remains uncertain. For 211Hg, 211Tl, 211Ac and 211Th nuclei, only the ground-state information is available. Their decay characteristics are mostly unknown. 211Fr is suggested to decay partially through ε decay mode, but its decay scheme remains poorly known. While high-spin excitations, including several isomers, are well studied in 211Pb, 211Bi, 211Po, 211At, 211Rn and 211Fr, the particle-transfer data are available for only 211Po and 211Bi.This evaluation was carried out as part of joint IAEA-ICTP workshop for Nuclear Structure and Decay Data, organized and hosted by the IAEA, Vienna and ICTP, Trieste, August 6-17, 2012. This work supersedes previous A=211 evaluation (2004Br45) published by E. Browne which covered literature before January 2003. © 2013 Elsevier Inc. Source

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