Satyanarayanan S

The present study reports developing a bench-top Laser-Induced Breakdown Spectroscopy (LIBS) set up for the online analysis of powder samples without sample preparation. The powder particle blow-off during pulsed laser ablation was mitigated by adding a blow gas (an inert gas blown across the ablation surface) and a suction unit (for extraction of the blow gas and blown-off particle cloud) to the existing LIBS setup. The influence of a blow-gas combined with a suction unit on LIBS emission intensity from coal powder and flyash particles is studied in the present work. The effect of the blow gas flow rate and the suction pressure was studied on the LI-BS emission intensity and removal of the laser blown-off particle cloud. The combination gas flow at 2 lpm (liter per minute) flow rate and suction at 925 mbar (absolute) show an increase in the LIBS emission intensity and effective particle removal. The ratio of LIBS emission intensity of the powder sample and solid-target (pellet) sample improved from 0.25 without the Ar gas flow and the suction unit to 0.85, which is by a factor of 3.4 times with the proposed approach.

Dual-wavelength, broadband photoacoustic technique is demonstrated for measurement of multiple gas species using a supercontinuum laser source. H2O vapor and CO2 measurements are demonstrated near 1920 and 2000 nm.

Nanosecond and femtosecond laser Induced Breakdown Spectroscopy (ns- and fs-LIBS)were used for elemental analysis of Indian coal and ash. Emissions from C, Na, K, Al, Fe, Ca and molecular CN were identified and analyzed.

Process industry mostly uses steam as an indispensable source of energy. We are presenting a technique to measure quality in real time where single laser diode tuning capabilities is being utilized to generate arbitrary modulated laser intensity for non-absorbing and absorbing wavelength of water vapor and eliminates uses of multiple laser source.

The origin, formation mechanism, and emission persistence time of atomic (C I) and molecular (CN Violet system and C2 Swan system) carbon emissions from coal plasma generated by laser ablation were studied using Time-resolved LIBS.

The present study proposed and demonstrated the feasibility of the fiber-based LIBS technique for the analysis of pulverized coal. A hollow-core fiber was employed to replace the air medium in the conventional LIBS setup for the delivery of high-power laser pulses to the target. It was observed that the hollow-core fiber could effectively deliver the laser energy for target ablation with a transmission efficiency of 50–60%. The LIBS spectra captured using the fiber LIBS technique prove that the addition of hollow-core fiber can upgrade the conventional LIBS technique into a remote characterization unit. Convincing results were obtained in terms of quantitative carbon measurement using the proposed approach.

Saturated steam dryness is derived from the refractive index measured using the Michelson Interferometer. For the measurement, the interdependence of the refractive index on wavelength, temperature, pressure, and density is used. The methodology is non-invasive and eliminates the use of multiple sources for dryness measurement.

Supercontinuum laser-based broadband photoacoustic technique is demostrated for sensing CO, CO2 and H2O around 2µm. The detection limit of 6 ppm, 736 ppm and 20 ppb respectively, is attained with SNR of 3 dB.

Supercontinuum laser-based broadband photoacoustic technique is demostrated for sensing CO, CO2 and H2O around 2 μm. The detection limit of 6 ppm, 736 ppm and 20 ppb respectively, is attained with SNR of 3 dB.

Nanosecond and femtosecond laser Induced Breakdown Spectroscopy (ns- and fs-LIBS) were used for elemental analysis of Indian coal and ash. Emissions from C, Na, K, Al, Fe, Ca and molecular CN were identified and analyzed.