Browsing by Author "Monika"

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3D attenuation tomography of the Uttarakhand, NW Himalaya: Linkage to fluid or partial melt zones - Seismic hazard
(Elsevier Ltd, 2024) Monika; Parveen Kumar; Sandeep; A. Joshi; S.K. Pal
This work proposes the shear-wave attenuation tomography of the Garhwal and Kumaun regions, Uttarakhand Himalaya, to investigate the crustal state. Based on attenuation characteristics, the high attenuated layer identified starts at ∼10 km in the Garhwal region and ∼5 km in the Kumaun region. The obtained model revealed that quality factor (Q) values vary from 16 to 664 and 49 to 866 at 1 Hz frequency for the Kumaun and Garhwal regions, respectively. The high attenuation rate (1/Q) in the Kumaun region compared to the Garhwal region may be due to the high attenuated layer at a shallower depth in the Kumaun region. The comparatively low attenuation rate of the Garhwal characterizes it as a region with high seismic hazard potential. Pioneeringly, layered frequency-dependent attenuation models are proposed up to a depth of 30 km for six different layers with 5 km thickness each, which will provide new insight into seismic hazard evaluation. © 2024 Elsevier Ltd
Anion directed structural diversity in zinc complexes with conformationally flexible quinazoline ligand: Structural, spectral and theoretical studies
(Royal Society of Chemistry, 2016) Nidhi Dwivedi; Sumit Kumar Panja; Monika; Satyen Saha; Sailaja S. Sunkari
In this paper, we report the synthesis, structure and photophysical studies of four new complexes of conformationally flexible 6-chloro-4-phenyl-2-(pyridin-2-yl)quinazoline ligand (L) with Zn(ii). The coordinating ability of the ligand and geometrical preferences of the resultant complexes are tuned by varying the anion of the metal salt as confirmed by structural and DFT studies. The choice of the metal salt (especially anion) directs the stabilisation of different conformations of the ligand arising out of twisting of the pyridyl ring with respect to the quinazoline ring, resulting in complexes with different nuclearity (monomer/dimer) as well as different coordination geometries (tetrahedral/trigonal bipyramidal/octahedral). Photophysical properties are also found to be tuned due to conformational changes on complexation. DFT studies on the ligand establish the conformationally stable forms as observed in the reported structures. © The Royal Society of Chemistry 2016.
Application of Wastewater in Irrigation and Its Regulation with Special Reference to Agriculture Residues
(Springer Singapore, 2021) Monika; Rajeev Pratap Singh; Pooja Singh; Richa Kothari; Kaushik Gautam; Anita Singh
Growing urban agglomeration across the world has promoted unscientific disposal of wastewater. In this view, wastewater exploitation in agriculture is a sustainable way of its utilization. Application of wastewater as irrigation water serves several goals such as promoting sustainable agriculture in an arid and semiarid region, preserving scarce water resources, and maintaining growth of plants. However, inadequate practices of wastewater application in present decades have resulted severe environmental issues like degrading river quality, groundwater pollution, heavy metal contamination, deterioration in soil health and nearby water reservoir quality, etc. With the treatment, the wastewater can be purified up to a certain level, but they cannot remove some constituents like heavy metals, pesticides, and other organic and inorganic compounds. Due to the unpredictable and unstable nature of wastewater, this becomes costly to treat either physically, chemically, or biologically. In this context, with the application of some sustainable strategies, the contamination can be reduced up to a certain extent particularly for heavy metals. Among all strategies, the applications of agricultural residues such as rice husk, sawdust, and other amendments are found to be the most suitable and lucrative way of reducing metal availability. Therefore, adjusted and scientific use of wastewater with certain treatment can be an economic and environmentally sustainable alternative to chemical fertilizers for enhancing crop productivity and crop yield and, at the same time, help in handling wastewater as a valuable resource. © Springer Nature Singapore Pte Ltd. 2021.
Assessment of Site Amplification Using Borehole and Surface Data: Variability of Site Effect Estimation from Different Phases of the Accelerogram
(Springer Science and Business Media Deutschland GmbH, 2022) Parveen Kumar; Sandeep; Monika
Site amplification is evaluated using the borehole and surface data for the central Honshu region, Japan. This study investigates the role of different phases of the records towards the site amplification. In present work, different phases of the earthquake record, i.e. P-phase, S-phase and full waveform are analysed to check the variation of site effect obtained using these phases. Site amplification is estimated by using the horizontal to vertical spectral ratio (H/V) method proposed by (Lermo and Chavez-Garcia in Bull. seism. Soc. Am. 83:1574–1594, 1993). A total of 174 surface and borehole acceleration records of 26 local earthquakes occurred in Central Honshu region during the years 2008 to 2017 is utilized in this work. The large amplitudes of H/V curves observed at the surface as compare to borehole, indicates the presence of site amplification at surface in contrast of borehole. It also reflects the existence of soft and unconsolidated deposits at the surface as compare to borehole. The comparison of site amplification obtained using P-phase, S-phase and full waveform of acceleration record revealed that amplitude of H/V curve obtained using S-phase and full waveform is almost similar, whereas h/v curve of P-phase has low amplitude than h/v curve of S-phase and full waveform. This comparison is made separately for both surface as well as borehole data, and the same observation is observed in both cases. Hence, it is concluded that S-phase has major contribution towards the site amplification of acceleration record as compare to P-phase. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Characterization of shear wave attenuation and site effects in the Garhwal Himalaya, India from inversion of strong motion records
(Springer, 2021) Parveen Kumar; Monika; Sandeep; Sushil Kumar; Richa Kumari; Dinesh Kumar; Narendra Kumar
Research highlights: The frequency-dependent shear-wave quality factor and site amplification are computed simultaneously for the Garhwal region, NW Himalaya.A regional quality factor relationship of form, Qβ(f) = (102 ± 3.9)f(1.0±0.1) is established for the Garhwal Himalaya.The acceleration records corrected from the obtained site effect are used to develop attenuation relations at each recording station.The close resemblance of obtained Qβ(f) relations and the geology has been observed for the study region. Abstract: The frequency-dependent shear-wave quality factor (Qβ(f)) and site amplification are computed for the seismically and tectonically active Garhwal Himalaya. The inversion technique of strong motion data is applied to obtain Qβ(f) and site effect at each recording station. The strong motion data of 82 earthquakes recorded in the Garhwal region is used for the present inversion algorithm. The comparison of site effects obtained by the present inversion scheme and well developed H/V technique (H/V is the ratio of Fourier spectra horizontal to vertical components) shows that site effects computed through the inversion technique have close resemblance with these estimates from the H/V technique. Both horizontal components are used to establish the frequency-dependent Qβ(f) relations at each station. The values of ‘Qo’ and ‘n’ at different stations vary from 92 to 112 and 0.9 to 1.1, respectively. The close resemblance of obtained Qβ(f) relations at different stations suggest, the presence of almost similar type of lithology, i.e., hard rock at these stations. A regional quality factor relationship of form, Qβ(f) = (102 ± 3.9)f(1.0±0.1) is established for the Garhwal Himalaya based on modelled Qβ values of each station. This relationship reveals low Qo value (<200) and high n value (>0.8) for the Garhwal Himalaya, which correspond to tectonically and seismically active region. © 2021, Indian Academy of Sciences.
Chemical modification of poly (vinyl chloride) sheet with thiourea for cell study
(2013) Monika; R.R. Mishra; S. Jaiswal; G. Kapusetti; N. Misra
Plasticized poly (vinyl chloride) has been used as biomaterial to make medical equipment. An appropriate reaction situation by temperature at 60-85°C for the surface modification of PVC sheet with sodium thiourea has been investigated. Although, the use of a phase-transfer catalyst (Tetra butyl ammonium hydrogen sulphate-TBHAS) makes it feasible for the nucleophilic substitution reaction to take place, the morphology of the film is changed by the reaction, leading to a loss in both surface smoothness and transparency of the film. According to this study, the reaction with sodium thiourea occurs consistently through the sheets, and modified surface have antibacterial capacity. © 2013 AIP Publishing LLC.
Chemical modification of poly(vinyl chloride) for blood and cellular biocompatibility
(Royal Society of Chemistry, 2015) Monika; Sanjeev Kumar Mahto; Snehashish Das; Amit Ranjan; Santosh Kumar Singh; Partho Roy; Nira Misra
Poly(vinyl chloride) (PVC) was modified with three different ionomers including thiosulphate, thiourea and sulphite for improving the biocompatibility of the polymer. All ionomers were prepared by nucleophilic substitution using a phase transfer catalyst method. The modified forms of PVC were characterized using ultraviolet-visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). They were found to be less stable thermally compared to the untreated polymer. The biocompatibility of the polymers was evaluated by assessing their wettability via contact angle measurements and by performing hemolysis and thrombogenicity assays. Their cellular biocompatibility was evaluated by assessing their adhesion and proliferation, and by carrying out cytotoxicity assays and nuclear staining. The results reveal that modification of the polymer with the specified ionomers significantly enhances the bio- and blood-compatibility properties. This journal is © The Royal Society of Chemistry.
Color tunability and NIR luminescence in Cr3+/Li+ co-doped ZnGa2O4 phosphor for solid state lighting and NIR LEDs
(Institute of Physics, 2023) Monika; R.S. Yadav; A. Bahadur; Shyam Bahadur Rai
In this work, we report the color tunable photoluminescence in the Cr3+/Li+ doped and co-doped ZnGa2O4 (ZGO) phosphors synthesized by solid state reaction method. The phase and surface morphology of ZGO phosphor were examined by XRD and SEM measurements, respectively. The EDS spectra revealed the presence of Zn, Ga, Cr and O elements in the phosphor. The vibrational structure of the phosphor materials has been analyzed by FTIR measurements. The Cr3+ doped phosphor shows electronic absorption bands at 302, 408 and 544 nm alongwith the host CTB at 260 nm. The optical band gap of the phosphor decreases via doping of Cr3+ and Cr3+/Li+ ions. The ZGO is a self-activated host and emits broad blue emission with maximum at 434 nm upon excitation at 260 nm. The Cr3+ doped phosphors show emission bands due to spin-allowed as well as spin-forbidden transitions due to Cr3+ ion in the blue, green and NIR regions on excitation with 260, 302, 408 and 544 nm wavelengths. The emission intensity is optimum for 0.5 mol% concentration of Cr3+ ion. The emission intensity of Cr3+ doped ZGO phosphor increases via doping of Li+ ion. The color tunability has been observed in the phosphor upon 260 and 302 nm excitations. The lifetimes of 4T2 (4F) and 2E states of Cr3+ ion have been measured and it is found that it decreases with increasing concentrations of Cr3+ and Cr3+/Li+ ions. The Cr3+/Li+ doped and co-doped ZGO phosphors may be suitable candidates for display devices, solid state lighting and NIR LEDs. © 2023 IOP Publishing Ltd.
Concentration and pump power-mediated color tunability, optical heating and temperature sensing via TCLs of red emission in an Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor
(Royal Society of Chemistry, 2019) Monika; Ram Sagar Yadav; Amresh Bahadur; Shyam Bahadur Rai
Intense red upconversion luminescence was observed in the Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor synthesized through the solid state reaction method for the first time. The structural characterization showed a large crystalline nature and an increase in the particle size via Li+ doping. The absorption spectra showed a large number of peaks in the UV-vis-NIR regions due to the Er3+ and Yb3+ ions. The Er3+/Yb3+ co-doped ZnGa2O4 phosphor exhibited green, red and NIR upconversion emissions on excitation with 980 nm radiation. The intensity of the red emission was relatively larger than that of the other emissions. The luminescence intensity versus pump power measurements revealed the number of required photons for these emissions. The phosphor showed very interesting color tunability as a function of Er3+ ion concentration and incident pump power. The luminescence intensity of the Er3+/Yb3+ co-doped phosphor was enhanced more than two times via Li+ doping. The enhancement in the luminescence intensity was proposed to be due to the increase in the crystallinity and particle size of the phosphor. The lifetimes of the 4S3/2 and 4F9/2 levels also increased in the presence of Li+ ions. The variation in the fluorescence intensity ratio (FIR) of the thermally coupled levels (TCLs) of the red emission with incident pump power offered effective optical heating in the phosphor. The temperature-induced FIR using TCLs of red emission exhibited a larger value of temperature sensing sensitivity in the presence of Li+ ions, which was up to 14 × 10-4 K-1. Thus, the Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor may be used in photonic, optical heating, and temperature sensing devices. © 2019 The Royal Society of Chemistry.
Determination of Arias intensity and modified Mercalli intensity scale for future scenario earthquake in the Uttarakhand Himalaya, India
(Springer, 2025) Parveen Kumar; Sandeep; Sandeep Kumar; Monika; Narendra Thrideep Kumar
The present work proposes the assessment of seismic hazards in the Uttarakhand Himalaya using Arias intensity (Ia) and modified Mercalli intensity (MMI). The Ia is computed using acceleration waveform data and the available empirical relation. A close similarity of Ia values computed from waveform data and empirical relation validates the applicability of this relation for the Uttarakhand Himalaya. After validation, the empirical relation is applied to generate the Arias intensity map for earthquakes of magnitude ≥ 4.5, and it is correlated with the available MMI scale. Subsequently, an empirical relationship is established between the obtained Ia values and the MMI scale. This relation is further utilized to prepare the Ia and isoseismal map in terms of the MMI scale for future potential earthquakes of magnitude 7.5 and 8.5 (Mw). The proposed isoseismal map for future anticipated earthquakes (M 8.5) reveals that a large population along with famous sanctuaries like Badrinath, Kedarnath, and Haimkunth Sahib falls within MMI scale ≥ IX, which causes considerable damage. The simulated results provide maximum peak ground acceleration (PGA) values of 840 gals and 513 gals for the 8.5 and 7.5 magnitude scenario earthquake at the Uttarkashi station. The present study identifies the vulnerable zone for seismic hazards, which provides insight into assessing and mitigating the risks associated with the study region. © Indian Academy of Sciences 2025.
Erratum: Loss of collectivity in 79Rb (European Physical Journal A (2006) 28 (277-281) DOI:10.1140/epja/i2005-10286-8)
(2006) R.K. Sinha; A. Dhal; P. Agarwal; S. Kumar; Monika; B.B. Singh; R. Kumar; P. Bringel; A. Neusser; R. Kumar; K.S. Golda; R.P. Singh; S. Muralithar; N. Madhavan; J.J. Das; K.S. Thind; A.K. Sinha; I.M. Govil; R.K. Bhowmik; J.B. Gupta; P.K. Joshi; A.K. Jain; S.C. Pancholi; L. Chaturvedi
[No abstract available]
Estimation and Validation of Arias Intensity Relation Using the 1991 Uttarkashi and 1999 Chamoli Earthquakes Data
(Springer International Publishing, 2024) Parveen Kumar; Sandeep; Monika
Arias intensity is one of the most crucial ground motion parameters to estimate the amplitude, frequency and ground shaking duration content. In the present work, we have estimated Arias intensity for the Garhwal Himalaya, India using: (1) strong motion data of the 1991 Uttarkashi earthquake and the 1999 Chamoli earthquake and (2) available empirical relations. Further, these results are compared at several stations, and a close resemblance of estimated Arias intensity from the recorded data and empirical relations is observed, which validates the empirical relation for the present study region. Furthermore, the study region (30.0°N – 31.0°N; 78.6°E – 79.6°E) is divided into 100 small grids, and the Arias intensity values are computed at each grid. These values calculated at each corner of the grid are further utilized to prepare the contour maps of Arias intensity for the Garhwal Himalaya, India for the 1991 Uttarkashi (Mw 6.8) and the 1999 Chamoli (Mw 6.6) earthquakes. The Arias intensity maps are also prepared for the future scenario of earthquakes of magnitude Mw 8.5, keeping the rupture location at the epicentre of the Uttarkashi and Chamoli earthquakes. The Arias intensity maps reveal that 51% and 45% of the area consist of ˃ 0.11 m/s Arias intensity susceptible to landslide corresponding to the Uttarkashi and Chamoli earthquakes, respectively. Hence, the obtained Arias intensity is revealed to be a trustworthy parameter to define earthquake shaking essential to generate landslides. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.
Frequency-dependent Layered Q Model and Attenuation Tomography of the Himachal North-West Himalaya, India: Insight to Explore Crustal Variation
(Birkhauser, 2024) Parveen Kumar; V.J. Sahakian; Monika; Sandeep
The three-dimensional attenuation structure and frequency-dependent attenuation layered model are proposed for constraining seismic hazards and exploring the presence of an intra-crustal high conductive (ICHC) layer in the Himachal Himalaya, India. Using acceleration data recorded in the Himachal Himalaya, this work quantifies the attenuation characteristics in the form of shear-wave quality factor (Qβ). The low Qβ values (ranging 10–60) depict an aqueous fluid zone starting from a depth of ~ 11 km. This aqueous fluid identified in the study region closely resembles the ICHC layer identified by other researchers in its adjacent area. The geometry of the Main Himalayan Thrust (MHT) is explored in terms of the obtained attenuation model, which suggests the absence of a ramp structure of MHT below the Main Central Thrust (MCT) in the study region. The presence of an aqueous fluid zone identified at 11–20 km depth may be one of the possible reasons for high seismicity in the Himalayan seismic belt. This work also suggests a frequency-dependent shear wave attenuation (Qβ(f)) model of the form Qof n for six different layers of 5 km thickness each. The obtained layered model suggests low Q values, i.e., (49 ± 16) f (0.60±0.12) for layer 3 (10–15 km) and (27 ± 11) f (0.99±0.18) for layer 4 (15–20 km), corresponding to the aqueous fluid in the study region. The obtained Qβ(f) model appraises the region’s seismic hazard by describing the heterogeneity and tectonic activity level in the present study region. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.
From ACQ to AIE: The CN(π)-(π)Ar interaction driven structural and photophysical properties of aromatic ring conjugated novel diaminomaleonitrile derivatives
(Elsevier B.V., 2022) Monika; Abhineet Verma; Manish K. Tiwari; Navin Subba; Satyen Saha
Studying solid and solution state photoluminescence properties are exclusive to understanding Aggregation Caused Quenching (ACQ) and Aggregation Induced Emission (AIE) behaviour of organic molecules to explore the mechanism of molecular luminescence in greater detail. A unique hydrogen-bonded dimer with imperative interaction (CN)π—π(Ar) was designed and synthesized by selecting diaminomaleonitrile (DMN) as stator and decorated with different aromatic rotors (phenyl to pyrene). Depending on the intermolecular interaction present in the molecular system, (AIE) or (ACQ) has been observed and found to be tunable. The single-crystal x-ray diffraction analysis of these derivatives shows that AIE characteristics could be seen where to (CN)π—π(Ar) intermolecular interactions between the aromatic rotors and stator, coupled with NH––NC intermolecular hydrogen bonding is present, while the absence of these interaction reflected in ACQ observation. The significant impacts of steric, conjugation and electronic effects on the ACQ / AIE properties are presented based on crystallography analysis, optical spectra measurements and theoretical calculations. © 2022 Elsevier B.V.
Important role of the position of a functional group in isomers for photophysical and antibacterial properties: A case study with naphthalenemaleonitrile positional isomers
(Royal Society of Chemistry, 2020) Monika; Abhineet Verma; Supriy Verma; Nidhi Pandey; Ragini Tilak; Satyen Saha
The naphthalenemaleonitrile positional isomers, (1N: 2-amino-3-(((E)-naphthalene-1-ylmethylene)amino)maleonitrile) and (2N: 2-amino-3-(((E)-naphthalene-2-ylmethylene)amino)maleonitrile), were synthesized and then studied comparatively. Their molecular configurations exhibit an extraordinary ability to affect photophysical properties such as aggregation induced emission (AIE) and aggregation caused quenching (ACQ) properties and an unexpected structural dependence of antibacterial activity in biological cells. The 2N (naphthalene and aminomaleonitrile moieties are planar to each other) shows interesting AIE photophysical behaviours, whereas 1N (the naphthalene and aminomaleonitrile moieties are twisted around each other) exhibits the usual ACQ. The answer to the apparent contradiction of the general conception that planar molecules show ACQ in aggregates is hidden in the packing of molecules and the interactions present therein. Furthermore, 1N shows antimicrobial activity in a biological cell, whereas 2N does not. Although, the presence of a particular functional group such as imine is reported to be a determinant factor for a molecule to show antimicrobial activity, as far as is known, functional group position-dependent biological activities in aminomaleonitrile group containing molecules are not yet reported. Therefore, this report demonstrates that just the presence is not enough; the position of the functional group, which affects the structure of the molecule, is equally important. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Influence of Positional Isomerism on Modulating Crystal Packing and Physicochemical Properties of New Picolylamine-Based Fully Organic Ionic Salts
(John Wiley and Sons Inc, 2025) Supriy Verma; Amita Mahapatra; Abhineet Verma; Monika; Satyen Saha
The selective formation of positional isomers, along with the fine-tuning of physicochemical properties through structural variation, represents an effective crystal engineering strategy for the development of thermally stable and photoactive organic materials. Here in this report, three new fully organic ionic salts (namely, 2-picolylaminium p-toluenesulfonate; [2P][OTs], 3-picolylaminium p-toluenesulfonate; [3P][OTs], and 4-picolylaminium p-toluenesulfonate; [4P][OTs] based on the positional isomers of picolyl-amine as cation, and tosylate as anion have been synthesized in a single-step with atom economy at room temperature and are characterized by multinuclear NMR and HRMS techniques. Single-crystal X-ray diffraction (SCXRD) studies revealed a zig–zag fashion arrangement of cations in [2P][OTs], whereas [4P][OTs] exhibited a linear arrangement of cations within their crystal lattices. Raman spectroscopy further highlighted isomer-dependent shifts in the vibrational modes of the tosylate anions, suggesting that the positional variation of the functional group in the cation significantly influences the local ionic environment. Furthermore, the results of photophysical investigations show [3P][OTs] and [4P][OTs] are emissive in the solid state. However, [2P][OTs] do not show any visible fluorescence. The outcomes of this study emphasize the importance of positional isomerism for the rational design of desired materials. © 2025 The Author(s). ChemistrySelect published by Wiley-VCH GmbH.
Investigation of the high frequency attenuation parameter kappa (κ) beneath the volcanic region of Kyushu using surface and borehole dataset
(Elsevier Ltd, 2025) Sandeep; Sonia Devi; Pragya Singh; Udai Pratap Singh; Shiv Kumar Pal; Parveen Kumar; Monika; Ashok M.Praveen Kumar; Himanshu Mittal
This study focuses on a detailed analysis of the high-frequency attenuation parameter, kappa (κ), to better understand seismic wave propagation in the volcanic region of Kyushu. In this analysis, κ values are examined beneath the volcanic area of the Kyushu region using strong motion data from the 2016 Kumamoto earthquake. The Surface and borehole data are utilized to evaluate the effects of site conditions and regional attenuation characteristics, respectively. The site attenuation parameter (κ0) ranges from 0.022s to 0.068s, as estimated from 21 surface stations. The κ0 values correlate with average shear-wave velocity in the top 30 m (VS30), showing a decrease as VS30 increases. Additionally, using borehole data, the region-specific S-wave quality factor (Qs) and κ0 are estimated in this region, resulting in values of 846 ± 75 and 0.050 ± 0.002s, respectively. The relatively lower Qs values and higher κ0 values observed in this study may be due to the extensive volcanic activities in the Kyushu region. The findings closely match previous studies, highlighting significant attenuation in the volcanic region. The average κ values for borehole data are 0.043s–0.053s for horizontal components (κH) and 0.038s–0.051s for vertical components (κv). Surface data shows κH values from 0.061s to 0.070s and κV from 0.039s to 0.046s. A relative comparison shows κH and κv are roughly equal in borehole conditions, while surface conditions reveal κH exceeds κv due to site effects on horizontal components. The estimated κ values are crucial for future site-specific seismic hazard analysis in Kyushu's volcanic regions. © 2025 Elsevier Ltd
Loss of collectivity in 79Rb
(Springer New York, 2006) R.K. Sinha; A. Dhal; P. Agarwal; S. Kumar; Monika; B.B. Singh; R. Kumar; P. Bringel; A. Neusser; R. Kumar; K.S. Golda; R.P. Singh; S. Muralithar; N. Madhavan; J.J. Das; K.S. Thind; A.K. Sinha; I.M. Govil; R.K. Bhowmik; J.B. Gupta; P.K. Joshi; A.K. Jain; S.C. Pancholi; L. Chaturvedi
High-spin states in 79Rb were populated in the reaction 63Cu(19F, p2n) 79Rb at E(beam) = 60 MeV. The lifetimes of the excited states of the πg9/2 positive-parity yrast band and of the πp3/2 negative-parity band in 79Rb were measured by the Doppler Shift Attenuation Method. The deduced transition quadrupole moments Qt are found to have a decreasing trend with rotational frequency for both the bands, consistent with those found experimentally in neighbouring nuclei.
Modeling of 2011 IndoNepal Earthquake and Scenario Earthquakes in the Kumaon Region and Comparative Attenuation Study Using PGA Distribution with the Garhwal Region
(Birkhauser Verlag AG, 2019) Sandeep; A. Joshi; S.K. Sah; Parveen Kumar; Sohan Lal; Sonia Devi; Monika
Kumaon and Garhwal regions are the chief terrains of Uttarakhand Himalaya. The present article simulates the strong ground motion of the 2011 IndoNepal earthquake in the Kumaon region using modified semi empirical technique (MSET). Acceleration records at ten stations in the near field region have been simulated which validates well with actual records and therefore confirms the reliability of MSET. In addition, MSET has been used to simulate strong motion records of future scenario earthquakes (Mw 7.0 and Mw 8.0) in Kumaon region by assuming the earthquake location same as that of 2011 IndoNepal earthquake. Isoacceleration maps are also provided, which reveals more than 400 gal value of PGA at epicentral distances less than 25 kms for an earthquake of magnitude 8.0. The comparison of isoacceleration map of future scenario earthquake (Mw 7.0) in Kumaon region has been done with isoacceleration map of 1991 Uttarkashi earthquake (Mw 6.8) in Garhwal region which suggests distinct attenuation characteristics of these two regions. © 2019, Springer Nature Switzerland AG.
Modelling of 1991 Uttarkashi and 2011 Indo-Nepal earthquakes using the modified semi-empirical technique by integrating site-specific quality factor
(Springer, 2023) Monika; Sandeep; Parveen Kumar; Sonia Devi; A. Joshi
Strong ground motion simulation is a reliable tool for seismic hazard assessment and mitigation of any region. The distribution of hazards during an earthquake is greatly influenced by the attenuation properties of the medium. Typically, regional attenuation characteristic is employed for strong motion simulation rather than site-specific attenuation. In the current study, the newly developed semi-empirical simulation approach is modified to use a site-specific attenuation relation. Initially, the medium attenuation characteristics are quantified by estimating frequency-dependent S-wave quality factor (Qβ(f)) at each recording station. These obtained Qβ(f) relations at each station are further utilised to estimate the regional relation for the Garhwal and Kumaon regions as (90±4)f (0.86±0.05) and (54±2)f (0.89±0.1), respectively. These values suggest that the Garhwal region is relatively less attenuative and more credible for seismic hazards compared to the Kumaon region. The Qβ(f) obtained at each recording station are further used to simulate the 1991 Uttarkashi (Mw 6.8) and 2011 Indo-Nepal (Mw 5.4) earthquakes. An improved match is perceived between the observed and simulated records with site-specific Qβ(f) values instead of regional ones. This comparison successfully validates the present modification in SET. This work provides insight into getting more realistic simulated results and explores recent trends in strong motion seismology for seismic hazard evaluation. © 2023, Indian Academy of Sciences.