Article
Chemistry, Analytical
Ziyu Yu, Shunchun Yao, Yuan Jiang, Weize Chen, Shuixiu Xu, Huaiqing Qin, Zhimin Lu, Jidong Lu
Summary: This paper investigates the matrix effect in coal analysis using laser-induced breakdown spectroscopy (LIBS), comparing the effect in coal particle flow with that in coal pellets. The study demonstrates that analyzing coal particle flow with LIBS can reduce the matrix effect and improve the stability of analytical results.
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2021)
Article
Materials Science, Multidisciplinary
Hemalaxmi Rajavelu, Nilesh J. Vasa, Satyanarayanan Seshadri
Summary: This study proposed and demonstrated the feasibility of a fiber-based LIBS technique for analyzing pulverized coal. By replacing the air medium with a hollow-core fiber, high-power laser pulses were effectively delivered to the target for ablation with a transmission efficiency of 50-60%. The addition of the hollow-core fiber upgraded the conventional LIBS technique into a remote characterization unit, as proven by the captured LIBS spectra.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Chemistry, Multidisciplinary
Qi Ni, Yanqun Zhu, Wenyu Zhu, Yong He, Zhihua Wan
Summary: In this study, four different calibration strategies were applied to coal analysis using laser-induced breakdown spectroscopy (LIBS). The prediction accuracy, precision, stability, and training velocity of four calibration models were compared. The results showed that support vector regression (SVR) and back-propagation training (BP) are the most promising calibration models in terms of prediction accuracy and precision. Partial least-squares regression (PLSR) had better prediction stability and faster training velocity, while random forest (RF) performed worse than the other three models.
Article
Spectroscopy
Weizhe Ma, Ziyu Yu, Zhimin Lu, Qingxiang Ma, Shunchun Yao
Summary: This paper proposes a step-by-step classification method to screen the false spectra of miscellaneous materials in coal analysis. The first step identifies the spectra of plastic and wood, while the second step classifies the spectra of gangue using a random forest classification model. Experimental results demonstrate that this method effectively identifies the spectra of coal and miscellaneous materials, improving the accuracy of coal analysis.
ATOMIC SPECTROSCOPY
(2023)
Article
Spectroscopy
Kristin Rammelkamp, Susanne Schroeder, Gianluigi Ortenzi, Alessandro Pisello, Katrin Stephan, Mickael Baque, Heinz-Wilhelm Huebers, Olivier Forni, Frank Sohl, Laurenz Thomsen, Vikram Unnithan
Summary: This study evaluated the performance of a commercial handheld LIBS instrument during an international summer school in 2019 and conducted exploration on an outcrop on the island of Vulcano in Italy, showing elemental variations between layers. The handheld instrument was able to identify geologically relevant major elements and minor elements through data analysis, providing insights into the limitations and challenges of using LIBS in terrestrial and planetary field investigations in the future.
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY
(2021)
Article
Chemistry, Applied
Eleni Nanou, Dimitrios Stefas, Stelios Couris
Summary: In this study, the inorganic content of different milk samples was investigated using Laser Induced Breakdown Spectroscopy (LIBS) technique. The optimal experimental conditions for measuring low concentration inorganic elements were determined by using infrared (1064 nm) and visible (532 nm) laser excitation conditions. Major (Ca, Na, Mg and K) and minor minerals (P, Zn, Cu and Si) were detected and identified through their spectral features. The LIBS results were in perfect correlation with the results obtained from atomic absorption measurements, indicating the potential of LIBS technique for fast and in-situ qualitative characterization of the inorganic content in milk samples of different animal origin.
Article
Chemistry, Analytical
Ji Chen, Qingzhou Li, Ke Liu, Xiangyou Li, Bing Lu, Guqiang Li
Summary: Moisture is a critical factor that interferes with laser-induced breakdown spectroscopy (LIBS) spectra and reduces the analysis accuracy. This study established regression models for volatile content and proposed a random spectral attenuation method to reduce moisture content disturbance. The results showed improved accuracy and speed of LIBS analysis with the use of these methods.
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2022)
Article
Instruments & Instrumentation
Hemalaxmi Rajavelu, Nilesh J. Vasa, Satyanarayanan Seshadri
Summary: A benchtop laser-induced breakdown spectroscopy is used to determine the elemental carbon content in raw coal. The relationship between carbon and other elements in coal is studied, and a calibration model is developed by combining spectral and temporal characteristics. Combining spectral data with temporal characteristics has improved the accuracy of measurement and reduced standard deviation.
APPLIED SPECTROSCOPY
(2021)
Article
Engineering, Environmental
Zifeng Luo, Tao Jia, Qianyan Liu, Yubao Song, Min Zhou, Xinxia Ma, Jiang Wu, Zhiwei Qin, Xuefei Wu
Summary: CIS/GCN sorbents, with abundant surface metal cation vacancies and sulfur sites, demonstrated excellent Hg0 removal performance and are considered a strong candidate for current commercial activated carbon.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Optics
M. Kuzmanovic, A. Stancalie, D. Milovanovic, A. Staicu, L. J. Damjanovic-Vasilic, D. Rankovic, J. Savovic
Summary: This study aimed to demonstrate the potential of Laser-Induced Breakdown Spectroscopy (LIBS) in analyzing pottery shards and identifying inorganic pigments used for decoration. The results showed correlations between the elemental composition of the glazed surface and its colors, consistent with previous analyses and supporting potential use for depth profiling. The study also estimated plasma characterization parameters and explored LIBS for depth profiling.
OPTICS AND LASER TECHNOLOGY
(2021)
Review
Chemistry, Analytical
Ke Liu, Chao He, Chenwei Zhu, Ji Chen, Kaiping Zhan, Xiangyou Li
Summary: This paper summarizes the methods of coal analysis using laser-induced breakdown spectroscopy (LIBS), including instrument collection of coal spectra, coal sample pretreatment, data preprocessing, and analytical chemistry methods. It also introduces the applications of LIBS in coal ranks, combustion efficiency, and environmental protection, and proposes the limitations and potential development trends in this field.
TRAC-TRENDS IN ANALYTICAL CHEMISTRY
(2021)
Article
Engineering, Environmental
Wenting Xu, Guochang Song, Xingyu Yang, Qiang Song, Qiang Yao
Summary: Understanding the transformation of Se during the flue-gas cooling process is important for controlling Se emissions. Physical migration was found to be the main pathway of Se transformation into ash, and the adsorption mechanism of gaseous Se was proposed through comparing adsorption characteristics and performing a speciation analysis.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Review
Engineering, Environmental
Ting Liu, Zhuo Xiong, Peng Ni, Zizhen Ma, Yan Tan, Zishun Li, Shengnan Deng, Yincui Li, Qirong Yang, Huawei Zhang
Summary: This review focuses on the current situation of Hg0 removal on different kinds of adsorbents in coal combustion flue gas, smelting flue gas, and natural gas. Hydrophobic groups, hydrophobic materials, and modification of sulfur/selenium pretreatment and metals loading can effectively overcome the problem of H2O and SO2. Additionally, separation, regeneration, and recovery aspects are explored and summarized, with thermal treatment accompanied by different components being widely adopted as an efficient approach to recover the adsorption ability.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Zifeng Luo, Ling You, Jiang Wu, Yubao Song, Siyuan Ren, Tao Jia, Xiaokun Li, Liping Chen, Yongfeng Qi, Ping He
Summary: This study introduces the method of introducing selenium ligands into ZnS to enhance Hg0 capture capability, with promising results showing 100% removal efficiency within a wide temperature range for 30SZ. The sorbent demonstrated excellent absorbent capability and minimal effects from O2 and SO2, with slight competition from NO for Hg0 adsorption.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Analytical
Xiaoyong He, Qi Yang, Dongxiong Ling, Dongshan Wei, Hongcheng Wang
Summary: Femtosecond laser ablation spark-induced breakdown spectroscopy (fs LA-SIBS) was developed for quantitative analysis of multiple metal elements in a steel alloy. The technique utilizes a femtosecond laser ablation source and spark discharge to excite the plasma and enhance atomic intensity, with plasma emission spectra recorded and analyzed using a compact fiber spectrometer. Compared to conventional LIBS, fs LA-SIBS offers superior analytical sensitivity and rapid high spatial resolution for quantitative elemental analysis.
Article
Physics, Applied
Tejaswi Josyula, Y. Esther Blesso Vidhya, Nilesh J. Vasa, Pallab Sinha Mahapatra, Arvind Pattamatta
Summary: Understanding the internal flow in evaporating sessile drops is crucial in various applications. This study reveals the nonaxisymmetric internal flow field caused by Marangoni flow at the liquid-vapor interface, and the transition to an axisymmetric toroidal flow during the evaporation process.
APPLIED PHYSICS LETTERS
(2022)
Article
Computer Science, Information Systems
G. Parvathy, Myneni Sukesh Babu, P. Sriram Karthick Raja, T. Thyagaraj, N. J. Vasa, R. Sarathi, Noureddine Harid, Huw Griffiths
Summary: The addition of lime to stabilize soil increases its strength and electrical properties, but pH and electrical conductivity decrease with longer curing periods. Analyzing mineralogical and micro-structural changes in the soil showed improvements in axial strength, plasma temperature, and electron number density with higher lime content and longer curing periods. Correlations between Ca II peaks in LIBS spectral data and lime content at different curing periods were successfully determined using PLSR technique with high accuracy.
Article
Engineering, Multidisciplinary
Pabbati Vinod, Myneni Sukesh Babu, Ramanujam Sarathi, Nilesh J. Vasa, Stefan Kornhuber
Summary: Silicone rubber insulators were studied for contamination level using laser-induced breakdown spectroscopy (LIBS) analysis, successfully identifying salt deposits on the surface even at far distances and any time. The normalized intensity ratio of sodium peaks was used to evaluate the salt deposit density accurately.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Optics
Sooraj Shiby, Nilesh J. Vasa
Summary: This study reports a method for pulsed laser-assisted micro-scribing of Cu from dielectric material, with monitoring using laser-induced breakdown spectroscopy (LIBS). Multiple laser scans were needed for complete Cu removal, and the Cu I line intensity in the LIBS spectra decreased as the microchannel depth increased. Additionally, characteristic emission lines from substrate elements were observed in the LIBS spectra during the final laser scan process.
OPTICS AND LASER TECHNOLOGY
(2022)
Review
Materials Science, Multidisciplinary
A. Raja, Srinivasa Rakesh Cheethirala, Pallavi Gupta, Nilesh J. Vasa, R. Jayaganthan
Summary: This article reviews the interrelationship between LPBF process parameters, microstructure, crack initiation, and crack growth mechanisms under fatigue loading conditions. It highlights the importance of standardizing mechanical testing techniques, specimen design guidelines, and post-manufacturing treatments for improving the fatigue resistance of AlSi10Mg alloy. The influence of microstructural features and post-processing conditions on fatigue properties is discussed, along with the crack growth mechanism observed in LPBF processed material.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Hemalaxmi Rajavelu, Nilesh J. Vasa, Satyanarayanan Seshadri
Summary: This study proposed and demonstrated the feasibility of a fiber-based LIBS technique for analyzing pulverized coal. By replacing the air medium with a hollow-core fiber, high-power laser pulses were effectively delivered to the target for ablation with a transmission efficiency of 50-60%. The addition of the hollow-core fiber upgraded the conventional LIBS technique into a remote characterization unit, as proven by the captured LIBS spectra.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
S. Sooraj, Y. R. Yugandhara, N. J. Vasa, A. Kavitha, S. Krishnan, M. Shigeki
Summary: In this study, the micro-scribing process of the Cu film on a dielectric substrate was investigated using lasers with different pulse durations. It was observed that the formation of recast layer near the microchannel occurred when using lasers with pulse durations of 6 ns and 500 ps, while no recast layer was observed when using lasers with pulse durations of 1 ps and 120 fs. XRD analysis revealed the presence of compressive residual stresses in the scribed region with the 6 ns and 500 ps lasers, and tensile residual stresses in the scribed region with the 1 ps and 120 fs lasers. Oxide layer formation was observed in all pulse regimes. A theoretical simulation was conducted to estimate the temperature on the dielectric substrate. Complete removal of Cu from the dielectric substrate would result in thermal damage. A hybrid micro-scribing technique, involving immersion in NaCl solution during the final laser scan, was demonstrated for nanosecond laser processing. Finally, a frequency selective surface (FSS) was fabricated using the hybrid scribing technique.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Sree Harsha Choutapalli, H. G. Prashantha Kumar, Emmanuel Paneerselvam, Nilesh J. Vasa, R. Jayaganthan
Summary: Fabrication of single-crystal silicon carbide thin films without impurities is crucial for microelectromechanical systems applications. Pulsed laser deposition combined with annealing can be used to grow 6H-SiC thin films at lower temperatures than conventional vapor deposition techniques. This study investigated the pulsed laser deposition of 6H-SiC thin films using two different silicon carbide targets and varying substrate temperatures. The results showed that smooth and continuous SiC film growth with low electrical resistance can be achieved using the reaction bonding technique.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Optics
Manish Chandra, Satyanarayanan Seshadri, Nilesh J. Vasa
Summary: This paper presents a dual-wavelength absorption-based approach for measuring and validating the steam dryness fraction of wet steam. The accuracy of the dryness measurement system using this optical method is determined to be +/- 1% for the range of dryness and operating pressure (1-10 bars) of wet steam.
Article
Thermodynamics
Sandeep Koundinya, J. Jothilingam, Satyanarayanan Seshadri
Summary: Using a high-temperature heat pump to generate steam can reduce CO2 emissions and achieve energy and cost savings. The study demonstrated the successful implementation and operation of such a system, which showed promising results in terms of environmental impact and economic benefits.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Engineering, Electrical & Electronic
K. Saran Kumar, Y. Esther Blesso Vidhya, Ramya Selvaraj, Satyanarayanan Seshadri, S. M. Shiva Nagendra, Nilesh J. Vasa
Summary: This article presents a dual-wavelength band broadband photoacoustic spectroscopy (BPAS) technique ideally suited to low-energy broadband sources for industrial and environmental multigas sensing applications. The proposed technique allows for comprehensive concentration measurement and eliminates the impact of cross sensitivity among gases. The MDL achieved for methane, ammonia, and carbon monoxide were 0.4 and 0.7 ppm, 0.3 and 1.8 ppm, and 2.6 ppm, respectively.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Manufacturing
Y. Esther Blesso Vidhya, Nilesh J. Vasaa
Summary: Light-trapping is crucial for thin film solar cells, and the use of surface micro/nanostructures can improve light absorption. This study demonstrates the reduction of reflection and enhanced light trapping by fabricating random nanocones on a-Si thin film surfaces. Experimental results show a significant decrease in reflectance and good stability in thermal tests.
MANUFACTURING LETTERS
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Sooraj Shiby, Yugandhara R. Yadam, Balamurugan T. Sivaprakasam, Kavitha Arunachalam, Nilesh J. Vasa
Summary: Micro-scale removal of Cu from a dielectric substrate using a hybrid technique of nanosecond laser-activated electrochemical micro-scribing has been demonstrated in this study. The technique successfully removed Cu from the dielectric material, improved surface morphology, and provided thermal protection.
LASER-BASED MICRO- AND NANOPROCESSING XVI
(2022)
Article
Thermodynamics
Anandu Surendran, Satyanarayanan Seshadri
Summary: The study introduces a novel Transcritical Ejector Regenerative STORC (TER-STORC) for dual-source heat recovery applications, which replaces the need for two-phase flows with a fully evaporated vapor regeneration via an ejector. Results show that the system achieves comparable performance to traditional systems with lower sensitivity to pressure drops and reduced power outputs.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
