Browsing by Author "Govind Kumar"

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Application of Raman Spectroscopy in Coal Research: A Case Study on Tatapani-Ramkola Coal
(Geological Society of India, 2025) Neeraj K. Upadhayay; Alok Kumar; Govind Kumar; Amiya Shankar Naik
Coal, an organic sedimentary rock derived through the coalification of ancient plant material, is a vital fossil fuel with extensive industrial applications. The maturity of its organic matter is a crucial indicator of thermal evolution and rank, which governs the physicochemical properties of coal and its potential suitability for various applications. Raman spectroscopy has emerged as a powerful and non-destructive analytical tool in coal studies, offering insights into structural and chemical properties of carbonaceous rocks. This technique is particularly effective in assessing coal rank and maturity of organic matter, as well as identifying microstructural changes during the pyrolysis process, which is critical for enhancing its application in energy production and other fields. This study examines the application of Raman spectroscopy in assessing coal maturity by analyzing the spectral characteristics of coal samples from the Tatapani-Ramkola coalfield in Chhattisgarh, India. Raman spectroscopy of Tatapani-Ramkola coal reveals broad ‘D’ (1348-1394 cm-1) and ‘G’ (1579-1591 cm-1) bands with low ID/IG ratios (0.30-0.58), indicating moderate maturity. The G-D band separation (176-239 cm-1) reflects the transformation of aliphatic structures into aromatic rings. FWHM (D band) values (153.52-224.01 cm-1) classify the coal samples as medium-rank sub-bituminous coal. © 2025 Geological Society of India, Bengaluru, India.
Association Between Cognitive Performance and Nutritional Status: Analysis From LASI-DAD
(SAGE Publications Inc., 2023) Manjusha Bhagwasia; Abhijith R. Rao; Joyita Banerjee; Swati Bajpai; Aruna V. Raman; Arunanshu Talukdar; Arvind Jain; Chhaya Rajguru; Lalit Sankhe; Debabrata Goswami; Ganapathy Sankaralingam Shanthi; Govind Kumar; Mathew Varghese; Minakshi Dhar; Monica Gupta; Parvaiz A-Koul; Rashmi Ranjan Mohanty; Sankha Shubhra Chakrabarti; Sathyanarayana Raju Yadati; Sharmistha Dey; Aparajit Ballav Dey
Malnutrition in low- and middle-income countries causes cognitive decline and other health problems. Harmonized Diagnostic Assessment of Dementia for Longitudinal Aging Study in India (LASI DAD) is an extensive study on late-life cognition and dementia. This study examines the link between nutrition and cognitive abilities in older adults using data from the LASI DAD. We conducted descriptive statistics on nutritional parameters (body-mass index, waist-hip ratio, and Mini-Nutritional Assessment), cognitive functions, and socio-demographic variables in 2,892 adults aged ≥60 years. Cognitive domains assessed included delayed recall, orientation, language, executive function, abstract reasoning, and attention. Cognitive impairment was defined as impaired performance in two or more domains. Mean age was 69.3 ± 7.1 years, 52.9% were female, and 57.5% were illiterate. Low body-mass index (adjusted OR: 1.88, p <.001), at risk of malnutrition (adjusted OR: 1.89, p <.001) and malnourished (adjusted OR: 2.86, p <.001) on Mini-Nutritional Assessment were associated with the presence of cognitive impairment. Better cognitive performance was associated with increased body mass index (adjusted OR: 0.74, p-.03), hemoglobin (adjusted OR: 0.91, p-.006), and serum albumin (adjusted OR: 0.38, p <.001). This study shows that nutritional status assessed by anthropometric measures and blood markers is strongly linked to cognitive performance in older adults. © The Author(s) 2023.
Deep phenotyping and genomic data from a nationally representative study on dementia in India
(Nature Research, 2023) Jinkook Lee; Sarah Petrosyan; Pranali Khobragade; Joyita Banerjee; Sandy Chien; Bas Weerman; Alden Gross; Peifeng Hu; Jennifer A. Smith; Wei Zhao; Leon Aksman; Urvashi Jain; G.S. Shanthi; Ravi Kurup; Aruna Raman; Sankha Shubhra Chakrabarti; Indrajeet Singh Gambhir; Mathew Varghese; John P. John; Himanshu Joshi; Parvaiz A. Koul; Debabrata Goswami; Arunansu Talukdar; Rashmi Ranjan Mohanty; Y. Sathyanarayana Raju Yadati; Mekala Padmaja; Lalit Sankhe; Chhaya Rajguru; Monica Gupta; Govind Kumar; Minakshi Dhar; Jorge Jovicich; Andrea Ganna; Mary Ganguli; Prasun Chatterjee; Sunny Singhal; Rishav Bansal; Swati Bajpai; Gaurav Desai; Swaroop Bhatankar; Abhijith R. Rao; Palanimuthu T. Sivakumar; Krishna Prasad Muliyala; Preeti Sinha; Santosh Loganathan; Erik Meijer; Marco Angrisani; Jung Ki Kim; Sharmistha Dey; Perianayagam Arokiasamy; David E. Bloom; Arthur W. Toga; Sharon L. R. Kardia; Kenneth Langa; Eileen M. Crimmins; Aparajit B. Dey
The Harmonized Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India (LASI-DAD) is a nationally representative in-depth study of cognitive aging and dementia. We present a publicly available dataset of harmonized cognitive measures of 4,096 adults 60 years of age and older in India, collected across 18 states and union territories. Blood samples were obtained to carry out whole blood and serum-based assays. Results are included in a venous blood specimen datafile that can be linked to the Harmonized LASI-DAD dataset. A global screening array of 960 LASI-DAD respondents is also publicly available for download, in addition to neuroimaging data on 137 LASI-DAD participants. Altogether, these datasets provide comprehensive information on older adults in India that allow researchers to further understand risk factors associated with cognitive impairment and dementia. © 2023, The Author(s).
Defining anthropometric thresholds (mid-arm circumference and calf circumference) in older adults residing in the community: A cross-sectional analysis using data from the population representative Longitudinal Aging Study in India (LASI DAD)
(BMJ Publishing Group, 2023) Manjusha Bhagwasia; Abhijith Rajaram Rao; Joyita Banerjee; Swati Bajpai; Pranali Yogiraj Khobragade; Aruna V Raman; Arunanshu Talukdar; Arvind Jain; Chhaya Rajguru; Lalit Sankhe; Debabrata Goswami; Ganapathy Sankaralingam Shanthi; Govind Kumar; Mathew Varghese; Minakshi Dhar; Monica Gupta; Parvaiz A Koul; Rashmi Ranjan Mohanty; Sankha Shubhra Chakrabarti; Sathyanarayana Raju Yadati; Sharmistha Dey; Jinkook Lee; Aparajit Ballav Dey
Objectives To identify factors associated with malnutrition (undernutrition and overnutrition) and determine appropriate cut-off values for mid-arm circumference (MAC) and calf circumference (CC) among community-dwelling Indian older adults. Design Data from the first wave of harmonised diagnostic assessment of dementia for Longitudinal Ageing Study in India (LASI-DAD) were used. Various sociodemographic factors, comorbidities, geriatric syndromes, childhood financial and health status were included. Anthropometric measurements included body mass index (BMI), MAC and CC. Setting Nationally representative cohort study including 36 Indian states and union territories. Participants 4096 older adults aged >60 years from LASI DAD. Outcome measures The outcome variable was BMI, categorised as low (<18.5 kg/m 2), normal (18.5-22.9 kg/m 2) and high (>23 kg/m 2). The cut-off values of MAC and CC were derived using ROC curve with BMI as the gold standard. Results 902 (weighted percentage 20.55%) had low BMI, 1742 (44.25%) had high BMI. Undernutrition was associated with age, wealth-quintile and impaired cognition, while overnutrition was associated with higher education, urban living and comorbidities such as hypertension, diabetes and chronic heart disease. For CC, the optimal lower and upper cut-offs for males were 28.1 cm and >31.5 cm, respectively, while for females, the corresponding values were 26 cm and >29 cm. Similarly, the optimal lower and upper cut-offs for MAC in males were 23.9 cm and >26.9 cm, and for females, they were 22.5 cm and >25 cm. Conclusion Our study identifies a high BMI prevalence, especially among females, individuals with higher education, urban residents and those with comorbidities. We establish gender-specific MAC and CC cut-off values with significant implications for healthcare, policy and research. Tailored interventions can address undernutrition and overnutrition in older adults, enhancing standardised nutritional assessment and well-being. © Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
Fluorescent onion-like carbons (OLCs) derived from diverse coal precursors
(Elsevier Ltd, 2025) Priyanka Gogoi; Prakash Kumar Singh; Govind Kumar; Bodhisatwa Hazra; Binoy Kumar Saikia
Onion-like carbons (OLCs) or Carbon nano-onions (CNOs) have diverse applications across various fields of science and technology due to their remarkable properties, including active fluorescent centres, a high surface-to-volume ratio, and negligible toxicity. Coal, a carbon-rich and predominantly black solid material, was used as a precursor for the synthesis of fluorescent onion-like carbons (OLCs). This study highlights the formation mechanism of OLCs from four different grade/rank of coal precursors along with their fluorescent behaviours. Four distinct coal samples with varying petrographic and chemical compositions were used to synthesize OLCs by using an ultrasonic-assisted wet-chemical oxidation method. The resultant coal-derived OLCs exhibit a quasi-spherical shape with an onion-like morphology. The fluorescent behaviour of synthesized OLCs was systematically investigated with respect to the nature of the precursor materials and the surface functionalities present in the nanostructures. The results indicate that the fluorescence characteristics of OLCs are significantly influenced by the incorporation of heteroatoms in the carbon framework, as well as the overall elemental composition, particularly the relative content of carbon and nitrogen present in the precursor materials. The OLCs exhibit fluorescence quantum yields (FLQY) of 16.87, 2.53, 14.29, and 24.16 %, corresponding to average particle sizes of 36.49 ± 0.200, 39.14 ± 0.032, 50.24 ± 0.128, and 95.29 ± 0.246 nm, respectively, for the four distinct coal-derived OLCs. Furthermore, this study highlights the potential of employing coals of various rank as precursor materials for the synthesis of self-co-doped OLCs enriched with heteroatom functionalities. This approach offers a simple, facile, and cost-effective route for scalable production of high-value carbon nanomaterials derived from different grade/rank of coal precursors. © 2025 Elsevier Ltd
Geochemical and petrological characteristics coupled with stable isotope of the Permian Gondwana coals from Tatapani–Ramkola Coalfield, Son–Mahanadi Basin, India: Insights for paleodepositional and paleoclimate conditions
(Elsevier B.V., 2025) Neeraj K. Upadhayay; Amiya Shankar Naik; Shweta Rai; Prakash Kumar Singh; Alok Kumar; Afikah Binti Rahim; Mohammed Hail Hakimi; Govind Kumar; Pramod Kumar Rajak
This study aimed to investigate the quality and rank of the Tatapani-Ramkola coal and decipher the paleoclimate and depositional conditions during coal formation, explicitly focusing on vegetation sources, detrital contributions, and paleomire conditions. The studied coals exhibit a moisture between 4.0 % and 12.8 % and a volatile matter yield in the range of 28.8–49.5 wt% (dry ash–free basis), classifying them as subbituminous–A to bituminous in rank. This finding is supported by the vitrinite reflectance (VRo) values between 0.5 and 0.7 %. Maceral compositions reveal the dominance of vitrinite (average 47.8–62.4 %) followed by inertinite (average 13.0–29.9 %) and liptinite (average 8.5–13.1 %). This finding of the maceral characteristics together with the mineral composition (primarily clay, carbonate, and sulfide), show that the Tatapani–Ramkola coals were formed under mildly oxic–to–anoxic conditions in limno–telmatic to telmatic paleomires and contributions from forest and herbaceous vegetation. Geochemical isotope indicators, such as δ13C (−24.149 ± 0.825 ‰) and δ15N (+2.710 ± 0.344 ‰), suggest that the coals formed from C3 land plants under warm and humid climate conditions. Major oxide ratios indicate a moderate to high degree of chemical weathering in the source area, further confirming the prevailing warm and humid climate during the peat accumulation. The detrital/authigenic index (DAI) suggests significant detrital influence and authigenic sediment formation in the Tatapani–Ramkola coals. This study provides critical insights into the depositional history and paleoclimate of the Tatapani–Ramkola Basin, contributing to a deeper understanding of Permian coal formation processes. © 2025 Elsevier B.V.
Maturity Parameter of Carbonaceous and Coaly Matter Revealed through Raman Spectroscopy
(Geological Society of India, 2024) A.S. Naik; Govind Kumar; Vishvajeet Singh; Prakash K. Singh; Manju Kumari; D. Mohanty; R.K. Majhi; N. Upadhyay
This article presents the results of ten coal samples of sub-bituminous rank collected from working mines in Chhattisgarh, India, and subjected to proximate and ultimate analysis, organic petrology and Raman spectroscopic study to reveal their maturity parameters and structural characteristics of carbonaceous materials. Vitrinite reflectance measurement was also performed to understand the maturity parameter, with values ranging from 0.35% to 0.57%. The research is unique as it combines petrological, geochemical and spectroscopic technique on coals of Hasdeo basin. Conventional parameter, volatile matter ranges from 21.83 and 33.68% suggesting low maturity. The ash yield values range from 12.04 and 26.61%. Petrographically, the coals are vitrinite rich ranging from 53.95 to 63.47% while the inertinite group range from 17.9 to 29.2%. The liptinite concentration the samples remain below 10%. The maceral constitution of the coals indicates carbonaceous materials undergoing early diagenetic phase. The Raman results showed the presence of the D and G bands, two prominent spectral signatures, which are typical of natural materials rich in carbon. The Raman shift recorded for the D band ranges from 1348 to 1385 cm-1 and for the G band, the Raman shift was recorded between 1607 to 1616 cm-1. The ratio of the various parameters derived from the two bands aid to understand the material response to the changing physical and chemical variables in the geological setup. The intensity ratio of the ID /IG band ranged from 0.15 to 0.79 (average 0.50), while the (G-D1) parameter ranges from 225 to 260 indicating heterogeneity in the samples. However, the ratio of AD1 /AG did not show any regularity, with values ranging from 0.07 to 1.85. The investigation elucidates that by integrating Raman spectroscopy analysis with vitrinite reflectance (VRo), we can discern distinctive structural attributes characteristic of immature kerogen. Furthermore, the petrological, proximate, and ultimate data collectively corroborate the carbonaceous, coaly material in its early stages of coalification. © 2024 Geological Society of India, Bengaluru, India.
Organic Petrological Facets and the Evolution of Paleomire, Matasukh Lignite Deposits, Rajasthan, India
(Springer, 2023) A.S. Naik; Vishvajeet Singh; D. Mohanty; R.K. Majhi; Govind Kumar; N. Upadhyay; Manju Kumari; Shweta Rai
The present research work attempts to understand the organo-petrological facets of the lignite hosted in the Tertiary successions in Rajasthan. The maceral diversity was analyzed qualitatively and quantitatively which recorded huminite as the dominant microscopic constituent followed by inertinite and liptinite. The rank parameter of coal evaluated through vitrinite reflectance measurement random (VRo) shows the values vary between 0.19 to 0.27% suggesting lignite in rank. The petrographic investigation point towards the primary phase of degradation of organic matter corroborated through the dominance of huminite suggesting frequent flooding and the presence of funginite, demonstrating intense fungal activity in the mire. The paleodepositional model records elevated values of gelification Index (GI) ranging from 1.63 to 3.88 with well-preserved cell structures pointing towards an early phase of coalification. The model and plot of GI and TPI show that the paleomire developed in a limnic setting. © 2023, Geological Society of India.
Prevalence of dementia in India: National and state estimates from a nationwide study
(John Wiley and Sons Inc, 2023) Jinkook Lee; Erik Meijer; Kenneth M. Langa; Mary Ganguli; Mathew Varghese; Joyita Banerjee; Pranali Khobragade; Marco Angrisani; Ravi Kurup; Sankha Shubhra Chakrabarti; Indrajeet Singh Gambhir; Parvaiz A. Koul; Debabrata Goswami; Arunanshu Talukdar; Rashmi Ranjan Mohanty; Raju Sathyanarayana Yadati; Mekala Padmaja; Lalit Sankhe; Chhaya Rajguru; Monica Gupta; Govind Kumar; Minakshi Dhar; Prasun Chatterjee; Sunny Singhal; Rishav Bansal; Swati Bajpai; Gaurav Desai; Abhijith R. Rao; Palanimuthu T. Sivakumar; Krishna Prasad Muliyala; Swaroop Bhatankar; Aparajita Chattopadhyay; Dipti Govil; Sarang Pedgaonkar; T.V. Sekher; David E. Bloom; Eileen M. Crimmins; Aparajit Ballav Dey
Introduction: Prior estimates of dementia prevalence in India were based on samples from selected communities, inadequately representing the national and state populations. Methods: From the Longitudinal Aging Study in India (LASI) we recruited a sample of adults ages 60+ and administered a rich battery of neuropsychological tests and an informant interview in 2018 through 2020. We obtained a clinical consensus rating of dementia status for a subsample (N = 2528), fitted a logistic model for dementia status on this subsample, and then imputed dementia status for all other LASI respondents aged 60+ (N = 28,949). Results: The estimated dementia prevalence for adults ages 60+ in India is 7.4%, with significant age and education gradients, sex and urban/rural differences, and cross-state variation. Discussion: An estimated 8.8 million Indians older than 60 years have dementia. The burden of dementia cases is unevenly distributed across states and subpopulations and may therefore require different levels of local planning and support. Highlights: The estimated dementia prevalence for adults ages 60+ in India is 7.4%. About 8.8 million Indians older than 60 years live with dementia. Dementia is more prevalent among females than males and in rural than urban areas. Significant cross-state variation exists in dementia prevalence. © 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.
Structural and maturity evolution of lignite using Raman spectroscopy and organic petrology of the Barmer basin, Rajasthan, India
(Springer, 2025) Om Prakash Kumar; P. Gopinathan; Amiya Shankar Naik; Pramod Kumar Rajak; Govind Kumar; Neeraj K. Upadhayay; Amit Karmakar; T. Subramani
This study investigates the structural and thermal evolution of lignite from the Barmer Basin, Rajasthan, India, using Raman spectroscopy and organic petrology. Lignite samples were collected from active mines in Kapurdi, Giral, and Sonari and analyzed through proximate and ultimate analyses, petrography and Raman spectroscopic techniques to assess their rank and structural characteristics. Vitrinite reflectance measurements, ranging from 0.24% to 0.38%, to assess maturation of organic matter. The volatile matter, a conventional maturity parameter, ranges from 38.5% to 46.5%, indicating low rank and limited thermal evolution. Ash yield values vary from 2.32% to 28.24%. Petrographically, the lignite’s are rich in huminite, ranging from 58.0% to 77.4%, with inertinite content between 3.6% and 13.6% and liptinite concentration from 5.4% to 13.0%. The maceral composition suggests carbonaceous materials in an early diagenetic phase. Raman spectroscopy reveal the presence of D and G bands, typical spectral signatures of carbon-rich natural materials. The Raman shift for the D band ranges from 1343 to 1391 cm−1 and for the G band, from 1565 to 1588 cm−1. The intensity ratio of the ID/IG band ranged from 0.71 to 0.97, while the (G-D1) parameter varied from 187 to 238 cm−1, indicating sample heterogeneity. However, the AD1/AG ratio shows an irregular pattern, with values between 1.19 and 2.74. The study demonstrates that integrating Raman spectroscopy with Vitrinite reflectance (VRo) provides insights into the structural attributes of immature kerogen which denotes organic matter that has not yet undergone sufficient thermal evolution to generate oil or gas, which is typical of low-rank coals like lignite. The petrological, proximate and ultimate analyses collectively confirm the carbonaceous, coaly material in its early coalification stages. This study emphasizes the use of Raman spectroscopy and Organic petrology as a proxy to evaluate lignite thermal evolution, enhance the interpretation of carbon structural disorder (e.g., D/G band ratios) and offer deeper insights into the aromaticity, maturity and heterogeneity of lignite, comparing its results with traditional maturity indicators. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.