Abstract
We present experimental results of the trace argon impurity puffing in the ohmic plasmas of Aditya-U tokamak performed to study the argon transport behaviour. Argon line emissions in visible ...and Vacuum Ultra Violet (VUV) spectral ranges arising from the plasma edge and core respectively are measured simultaneously. During the experiments, space resolved brightness profile of Ar
1+
line emissions at 472.69 nm (3p
4
4s
2
P
3/2
–3p
4
4p
2
D
3/2
), 473.59 nm (3p
4
4s
4
P
5/2
–3p
4
4p
4
P
3/2
), 476.49 nm (3p
4
4s
2
P
1/2
–3p
4
4p
2
P
3/2
), 480.60 nm (3p
4
4s
4
P
5/2
–3p
4
4p
4
P
5/2
) are recorded using a high resolution visible spectrometer. Also, a VUV spectrometer has been used to simultaneously observe Ar
13+
line emission at 18.79 nm (2s
2
2p
2
P
3/2
–2s2p
2
2
P
3/2
) and Ar
14+
line emission at 22.11 nm (2s
2
1
S
0
–2s2p
1
P
1
). The diffusivity and convective velocity of Ar are obtained by comparing the measured radial emissivity profile of Ar
1+
emission and the line intensity ratio of Ar
13+
and Ar
14+
ions, with those simulated using the impurity transport code, STRAHL. Argon diffusivities ~ 12 m
2
/s and ~ 0.3 m
2
/s have been observed in the edge (ρ > 0.85) and core region of the Aditya-U, respectively. The diffusivity values both in the edge and core region are found to be higher than the neo-classical values suggesting that the argon impurity transport is mainly anomalous in the Aditya-U tokamak. Also, an inward pinch of ~ 10 m/s mainly driven by Ware pinch is required to match the measured and simulated data. The measured peaked profile of Ar density suggests impurity accumulation in these discharges.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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•Oxidovanadium(IV/V) complexes with NNO donor ligand was synthesized and characterized.•Molecular Docking was used to study the molecular binding behaviour of all complexes.•The ...complexes were screened for the anti-diabetic activity.
Reaction of NNO donor Schiff bases with vanadyl sulphate afforded the complexes viz., VO(L1)(H2O)NO31, VO(L2)(H2O)NO32, VO(L2)(ImH)2SO4·H2O 3 and VO(L1)ImHNO34 (where, L1 = Acetic acid (2-hydroxy-3-methoxy-benzylidene)-hydrazide and L2 = 5-bromo-2-(E)-(pyridine-2-ylhydrazono)methylphenol). In complex 3 the oxidation state of vanadium was found to be +5, while in rest all complexes it was +4. The crystal structure of complex 3 was solved by single crystal X-ray analysis. In addition to synthesis, optical, infrared and electrochemical properties of these complexes were also carried out. Electron paramagnetic spectra of oxidovanadium(IV/V) complexes is reported as well. Docking experiments were performed to study the molecular binding behaviour of all complexes with α-glucosidase enzyme. An antidiabetic feature like α-amylase and α-glucosidase inhibition studies made them promising candidates as inhibitors of insulin enzyme.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
New homologous series of Schiff's base of 4-n-Alkoxy-2-hydroxy benzaldehyde (n = 2 to 8, 10, 12, 14, 16, 18) with 4-amino acetophenone and their Cu(II) metal complexes have been synthesized. The ...compounds were characterized using various spectroscopic techniques including FT-IR,
1
H-NMR,
13
C-NMR. Mesomorphic properties of these compounds have been investigated with polarizing optical microscope and differential scanning calorimeter. These compounds exhibit wide range SmA phase as confirmed by their typical optical texture under polarizing microscope.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Bayard-Alpert (BA) type hot cathode ionisation gauge is widely used to measure neutral pressure precisely in vacuum system below 10−3 Torr pressure. Neutral pressure measurement in magnetic ...confinement fusion experiments is quite challenging for standard BA type gauge due to higher pressure limitation and its ionisation is affected by strong magnetic and electrical fields. To overcome the above limitations, a special hot cathode ionisation gauge, named ASDEX Pressure Gauge (APG) system was developed by G. Haas at the Max-Planck-Institute, Germany. The APG system can work in high magnetic field up to 6 T and high temperature plasma environment with broad pressure measurement range from 10−1 to 10−6 mbar with fast response (<10 msec) and good noise immunity.
In the present work, we report the design and development of control and data acquisition of ASDEX Pressure Gauge (APG) for ADITYA Tokamak to measure real time neutral pressure during the high temperature plasma. The developed system can achieve synchronous control of gauge controller using General Purpose Interface Bus (GPIB) and data acquisition of ion emission current of gauge head using Peripheral Component Interconnect (PCI) based data acquisition module. Initially, the APG calibration with standard BA type hot cathode ionization gauge had been carried out using the test set-up of low magnetic field and ultrahigh vacuum system with gases like H2, Ar, He. For APG calibration for various pressure ranges of these gases, precise gas feed control system has been developed using controller based hardware and LabVIEW based software. After testing and calibration, the APG was installed on ADITYA tokamak and calibrated under high magnetic field of ADITYA. The developed APG control system is configurable for presenting the gauge parameters before the plasma discharge. During plasma discharge, the analog signal equivalent to neutral pressure is acquired in real-time using simultaneous sampling analog to digital converter (ADC) module. The acquired raw data and processed real time pressure can provide valuable neutral pressure/density information of Tokamak plasma.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In present study, with an hydrazido-based ligand and Cu, Ni metal(II) salts, three new mononuclear and one binuclear end-to-end thiocynate bridged complexes have been synthesized and characterized by ...various physico-chemical techniques.
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•Three new mononuclear and one binuclear end-to-end thiocynato bridged complexes have been synthesized and characterized by various physico-chemical techniques.•New complexes were fully structurally characterized using single crystal X-ray diffraction.•The classical image of an O-H⋯π interaction is a T shape with interacting hydrogen atoms approximately directly over the centre of the aromatic ring πc.•The inhibitory effect of the complexes were tested on a cell population with IMR 32 (neuroblastoma), MCF 7 (breast cancer), HepG2 (hepatocellular carcinoma), L132 (lung cells) cell lines by MTT assay.•Antioxidant super oxide dismutase activity measurements show that the complexes behave as superoxide dismutase mimics.
With an hydrazido-based ligand, C14H13N2O and Cu, Ni metal(II) salts, three new mononuclear Ni(HL)(NO3)(H2O)NO3,C14H15N5NiO8, 1, Cu(HL)(H2O)22NO3, C14H17CuN5O4, 2, Ni(HL)22ClO4, C28H30Cl2N6NiO12, 3 and one binuclear end-to-end thiocynate bridged Cu2(μ-SCN)2(L)2, C30H24Cu2N8O2S2, 4 complexes have been synthesized and characterized by physico-chemical techniques. All of the complexes were structurally characterized using single crystal X-ray diffraction. Complexes 1 and 2 have a penta-coordinated environment around the metal(II) centre, whereas complex 3 has a distorted hexa-coordinated geometry. In complex 4 two symmetry related, adjacent copper(II) coordination moieties are joined end-to-end in an unprecedented manner forming a thiocynate bridged, yielding a dicopper entity. The presence of two “symmetric” thiocynate bridges with Cu-SCN and Cu-NCS distances of 2.832 Å and 1.925 Å, respectively, results in a Cu⋯Cu distance of 5.503 Å. Binuclear complex, 4 exhibits a weak antiferromagnetic interaction between adjacent copper(II) centres. These copper(II) mononuclear and binuclear complexes have also been studied by X-band EPR spectroscopy. The crystal packing of these new complexes is stabilized by H-bonding, weak intermolecular interactions, CH⋯π and π⋯π interactions. Electrochemical data (CV and DPV) for the complexes shows MII → MI reduction activity. Electronic spectroscopy and computational features are examined by quantum chemical studies. The inhibitory effect of the complexes were tested on a cell population with IMR 32 (neuroblastoma), MCF 7 (breast cancer), HepG2 (hepatocellular carcinoma), L132 (lung cells) cell lines by MTT assay. Complex 3 showed a prominent cytotoxicity against the all cell lines. Expression levels of the Bax (pro-apoptotic) and Bcl2 (anti-apoptotic) genes were also studied, wherein the genes of interest showed a moderate down regulation after treatment with complexes 1 and 3. Finally, antioxidant superoxide dismutase activity measurements show that the complexes behave as superoxide dismutase mimics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The effective charge, Zeff, of the plasmas of the Aditya tokamak has been analyzed to understand its behavior. It has been measured through the monitoring of the visible bremsstruhlang continuum ...emission around 523.4 nm from the plasma using an optical fiber, interference filter and photo multiplier tube based visible spectroscopic system. It has been found that the values of Zeff fall in the range of 1.7-4.0 and decrease with increasing plasma electron density, ne and the incremental value of Zeff is inversely proportional to ne2. The value of Zeff reduces in the range of 1.7-2.5 in the discharges produced after the Li coating compare to the values of 2.0-3.5 range in the discharges before the Li coating in the Aditya tokamak. Details analysis on the contribution to Zeff from various impurities suggests that reduction of Zeff after Li coating is not only due to decrease of oxygen concentration, but also other impurities, such as iron, inside the plasma.
Abstract
A real-time density feedback control system with a 100 GHz
heterodyne interferometer has been designed, developed, and
commissioned in ADITYA-U tokamak. It consists of three subsystems
i.e. ...density measurement, feedback control, and gas fuelling. A
proportional feedback controller is configured in voltage amplitude
mode to operate the piezo valve for gas injection. Experiments are
performed during plasma discharges to achieve a predefined density
evolution as well as constant density. Stickiness of the piezo
valve restricts the temporal response of the valve. It is required
to minimize during the plasma discharge for a fast density response
which is achieved by a short preceding voltage pulse known as a
stick pulse. This paper describes the implementation of a real-time
density feedback control system which is successfully validated
using another existing 140 GHz interferometer system in ADITYA-U.
Moreover, the developed system consumes low power, is cost-effective
and re-programmable, can be easily upgraded, and provides interlock
with plasma parameters.
A 140 GHz phase-locked heterodyne interferometer system has been designed, developed and installed at Aditya Tokamak for real time density measurement. The interferometer uses a novel approach of ...zero-cross detection using in-phase and quadrature (IQ) signals with a single balanced mixer. The transmitter and receiver systems are phase locked by a 100 MHz crystal oscillator and the output signals are mixed in a single balanced mixer which produces highly stabilized intermediate frequency (IF) frequency of 2.0 GHz. This signal is further amplified by low noise amplifier (LNA) and power amplifier with built-in automatic gain control (AGC) of response time 5 ms. The AGC keeps the IF signal amplitude stable for 20–70 dB attenuation. This IF signal is further down converted to 100 KHz IQ signals using a synthesizer which is phase locked by the same 100 MHz crystal oscillator used for phase locking the transmitter and receiver oscillators. The 100 KHz IQ signals are digitized by built-in 12 bits ADCs and processed though FPGA programming for real time phase-density calculations. The developed system has minimum phase sensitivity of 0.07 radian and a time resolution of 5 μs with 10 KHz resolution for real time density measurement. The density evolution of plasma discharge and effect of gas puff on density built up is successfully measured in real time and presented in this paper.
On ADITYA-U tokamak, a spectroscopic diagnostic has been developed to measure the radial profile of visible continuum radiation for determining the plasma effective charge, Zeff, to study the ...impurity transport and MHD driven instabilities. It consists of the collimating lenses, optical fibers, a multi-channel wavelength selection system, and photo multiplier tubes. The optical system allowing continuum radiation measurements around 536 nm (the wavelength selection system) consists of set of lenses, optical fibers and an interference filter with diameter of 5 cm and bandwidth of 3 nm. The spatial profile of radiation with a spatial resolution of ∼ 3 cm has been recorded from eight lines of sight viewing the plasma using an UHV compatible rectangular view port placed on the bottom port of the ADITYA-U tokamak. The centrally peaked spatial profile of visible continuum radiation has been recorded from the ADITYA-U tokamak plasmas. The chord averaged Zeff values estimated from the brightness measured along the central chord fall within 2.5 to 4.1 for the electron densities of 1.0 - 2.2 × 1019 m−3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
