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Role of Mesoscale Eddies on Upper Ocean and Atmospheric Convection in the Bay of Bengal
No full textOceanic mesoscale eddies are omnipresent in the ocean due to their turbulent nature. Understanding oceanic mesoscale eddies are essential because they play a prominent role in transporting heat/salt, circulation, biological activities, and intensification/weakening of tropical cyclones. Bay of Bengal (BoB) is in the northeastern part of the Indian Ocean, where mesoscale eddy activity is high. Very few studies have attempted to understand statistical characteristics, the vertical structure of mesoscale eddies, and air-sea interaction processes related to mesoscale eddies. The autonomous eddy identification method is employed to identify and track mesoscale eddies in the BoB from daily data of sea surface height anomalies for 26 years from 1993 to 2018. Results show that the tracks of anti-cyclonic and cyclonic eddies in the BoB primarily propagate towards the west and southwest during all seasons. The annual occurrence frequency of mesoscale eddies demonstrates that most eddies are dominant over the western BoB, followed by the Andaman Sea. Using composite analysis, the present study investigated the surface features of eddy-induced temperature and salinity changes near anti-cyclonic and cyclonic eddies. Surface eddy-centric composite analysis reveals the existence of warm (cold) and diverse sea surface salinity (SSS) anomalies for anti-cyclonic (cyclonic) eddies. During winter, it is essential to note that the eddy-induced sea surface temperature (SST) and SSS anomalies depict the dipole patterns that show opposite phases for cyclonic and anti-cyclonic eddies. Observed diploe structures are consistent with the eddy rotation and background large-scale meridional gradient of temperature and salinity fields. The composite vertical structure of mesoscale eddies is examined using ARGO profiles collocated near eddies locations, revealing that the anti-cyclonic eddies have a deeper core compared with a core of cyclonic eddies. In addition, the present study investigated mixed layer dynamics near mesoscale eddies and quantified the processes responsible for the eddy-induced temperature and salinity variations using mixed layer diagnostic models near both anti-cyclonic and cyclonic eddies. Results show that the anti-cyclonic eddies deepen the mixed layer depth (MLD), whereas cyclonic eddies decline MLD across all seasons. Mixed layer heat budget analysis near eddy locations depicts that the primary factors responsible for eddy-induced temperature variations are the surface heat flux convergences and vertical entrainment. The salinity budget analysis near eddy locations reveals that horizontal advection and vertical entrainment are the predominant processes responsible for the eddy-induced mixed layer salinity variations.
The impact of mesoscale eddies on the turbulent fluxes and overlying atmosphere are investigated using the composite analysis. In general, it is assumed that anti-cyclonic eddies are related to the positive anomalies of SST, and cyclonic eddies are associated with negative anomalies. However, in the BoB, the composites of SST anomalies reveal the abnormal response of SST near anti-cyclonic and cyclonic eddies. The unusual association of cold SST near anti-cyclonic eddies and warm SST near cyclonic eddies in BoB are investigated by analyzing the mean composites of precipitation, OLR and turbulent fluxes. Results show that the anti-cyclonic eddies significantly enhance precipitation and convection, whereas the cyclonic eddies suppress convection. The composites of latent heat flux, and wind speed anomalies over surface cold anti-cyclonic eddies, reveal that the ocean loses heat, and the presence of stronger winds is responsible for the anomalous negative anomalies observed near anti-cyclonic eddies in the BoB. Vice-versa is evident in near-surface warm cyclonic eddies. The results show that the atmospheric response observed over mesoscale eddies is influenced by the intraseasonal variations (ISV), since both mesoscale eddies and ISV operated at same time scales. Therefore, it is difficult to separate the atmospheric ISV and the mesoscale variability, to understand the role of mesoscale eddies on atmospheric variability. However, the influence of atmosphere is averaged out by combining the surface warm, surface cold eddies together, and the anomaly obtained could be associated with the anti-cyclonic or cyclonic eddy.
The variability of mesoscale eddies and their influence on atmospheric convection during weak (2009) and strong (2013) monsoon seasons is examined in the present study. Results revealed that deep atmospheric (shallow) convection is observed over anti-cyclonic (cyclonic) eddies during the active monsoon season, and no such relationship is observed during the weak monsoon season. The impact of mesoscale eddies on the near-surface atmosphere is evidently observed using composite analysis in the BoB. The existing atmosphere and ocean-coupled models are poor in representing the air-sea flux exchanges or sometimes neglect the influence caused by these mesoscale features. Therefore, the air-sea interactions over the mesoscale eddies need to be considered to improve the accuracy level in the numerical model simulations
Mirabai as Text: Contested Histories, Liminal Spaces, and Marginalities
No full textMirabai, the sixteenth-century bhakti poet-saint, has a palpable presence in Indian literary-cultural tradition. Her lyrical compositions, popularly known as bhajans— distinctly established upon a private devotion and universal human suffering—are a pervading feature of the religio-political discourse in contemporary India, and have availed her a recognition that transgresses confines of time, space and culture. Bhakti, thriving around the margins in particular, evolved into a social renaissance that denounced ritualistic prayers and introduced liberal practices of performing devotion through the vernacular songs of personal suffering. Mira’s personal devotion toward the Hindu deity Krishna transgressed boundaries of class, caste, and gender hierarchies and had controversial reverberations in her told hagiographies, histories and legends. With the advent of the European orientalists in nineteenth century India, rewriting history became a trend as an inexorable strain of colonial poetics. With the intervention of native scholars and popular leaders, Mira’s legend metamorphosed into a counter-narrative of resistance and dissent against colonialism and the servile sensibilities it begot. However, while following Mirabai’s cultural footprints on their spiritual odyssey, they (mis)read her bhajans in their public and private dialogues to suit moral and nationalist ends. Consequently, her narrative underwent monumental alterations, depicting an erroneous image of Mirabai that contradicted both ‘factual’ aspects of her life and her perceived resistance. The Mira narrative(s) thus eventually transgressed into an epochal cultural renaissance by providing an alternative space for spiritual expression, and has accommodated generations of marginalized populace, especially women who have embraced the name, life, and suffering of Mirabai to voice their dissent through her bhajans till date. This thesis reads the shifting image of Mirabai as a literary-cultural ‘hybrid’ in Indian archives, including literary, critical and philosophical corpora, with particular focus on the politics of appropriation surrounding her canonical figure, and its implications on the gendered nuances of modern bhakti historiography. It subsumes within its operative locus the role performed by popular leaders such as M.K. Gandhi, Aurobindo Ghose, and Swami Vivekananda in recuperating Mirabai during the Indian freedom struggle movement to galvanize masses, especially women, to achieve moral and economic liberation, ascribing to her qualities that fit precisely into what was needed to become an ideal, chaste, all-enduring, and a ‘sacred’ woman-icon to emulate. Further, with the mobilization of women in the larger nationalist movement, they were able to transgress the thresholds of traditional domesticity and became active agents of non violent resistance, while subverting the idea of the ‘sacred’ and the ‘profane’ within the discursive ambit of the ‘nation.’ The thesis also explores contemporary literature on Mirabai, incorporating the ‘performative’ aspect of daily bhakti in public spheres, bridging the lacuna owed to centuries of cultural silencing and social oppression
Artificial Intelligence Enabled Classification and Prediction of Atrial Arrhythmias using ECG Signal Morphological Features
No full textThe Electrocardiogram (ECG) is a diagnostic tool that non-invasively captures and records the heart’s electrical impulses. Examining the electrical characteristics of the heart can unveil the presence of cardiovascular ailments and furnish insights into the performance of the intracardiac conducting tissue. Cardiovascular diseases (CVDs) are currently the primary cause of death globally. CVDs were responsible for the demise of 17.9 million individuals globally in 2019, accounting for 32% of all mortalities and further the prevalence will double in 2030. The causes of mortality for 85% of these people were heart attacks and strokes. According to recent data, in 2019, CVDs accounted for 38% of premature mortalities (under 70) attributed to non-communicable diseases. The most commonly occurring CVD globally is Atrial Fibrillation (AF), a type of atrial arrhythmia. Despite several attempts to diagnose CVDs precisely, many go undetected. The limited based knowledge acts as a drawback in diagnosing fast-evolving CVDs. Mostly CVDs are reported in the last stage, thus limiting the choices of methodological diagnosis to the healthcare fraternity. Prior research has primarily centered on ventricular arrhythmias, with insufficient attention given to arrhythmias associated with the atria. Furthermore, there is a dearth of morphologically based classifications for atrial arrhythmias. The purpose of this study is to analyze, classify, and predict various heart rhythms generated by the sinoatrial (SA) Node, atrial disorders, and atrial arrhythmias using Artificial Intelligence (AI) techniques such as Machine Learning (ML) and Deep Learning (DL) based on morphological features (e.g., peaks, waves, intervals) obtained from ECG signal. Initially, this work analyzed Heart Rate Variability (HRV) in Sinus Rhythm (SR) and Exercise-induced Sinus Tachycardia (e-ST) conditions in two phases. The first phase consisted of statistical analysis of the time and frequency domain parameters and morphological features such as P-wave and PP Interval (PPI). The analysis revealed a significant alteration in the durational aspects of the HRV features when compared to SR and ST. The subsequent phase of the study involves the creation of a Long Short Term Memory (LSTM) based Recurrent Neural Network (RNN) to forecast the heart rate of the e-ST condition. The model utilized HRV features as input for multivariate time series forecasting to predict the heart rate of e-ST volunteers. The work focused on classifying e-ST with other atrial arrhythmias, such as Atrial Tachycardia (AT), because of the heart rate is the same in both cases and it is a herculean task to differentiate manually based on the ECG signal. Primarily to classify SR, e-ST, and AT, the three ML algorithms used were Extra Trees (ET), Ridge Classifier (RC), and CatBoost (CB) classifier. The classification methodology relies on morphological characteristics extracted from the ECG signal. Subsequently, these features were prioritized based on their significance in distinguishing SR, e-ST, and AT. In the feature ranking plots, the atrial features were given utmost importance in classifying as these conditions directly influenced them. Later the focus of the work shifts to analyzing and classifying precursors of AF, which are AT and LAE. The morphological-based analysis and classification are needed to understand the occurrence of AF. The morphological features consisted of temporal and amplitude aspects of the ECG signal and features obtained from P-Wave Indices (PWI). The PWI gives better insights into the atria functions. The initial phase of the work was classifying SR, e-ST, AT, and LAE by developing stacked ML models, and the later half ranked the morphological features by a pie formula-based technique. The PWI-based features obtained the highest importance compared to the temporal and amplitude aspects of the ECG signal. Finally, this work classified types of AF such as Paroxysmal Atrial Fibrillation (PAF) and Persistent Atrial Fibrillation (PsAF) from Non-AF cardiac rhythm. The classification of AF subtypes and Non-AF is necessary to better the clinical decision management and delineate the A ’s clinical condition. The work proposes a 2D custom Convolutional Neural Network (CNN) model to classify AF subtypes automatically based on the time-frequency spectrum. After further converting ECG signals to time-frequency spectrum using Constant-Q Transform (CQT), the obtained plots acted as the input to the CNN model. The advantage of the time-frequency spectrum is that the features extracted by the CNN model are Intermediate Frequency (IF) and Spectral Delay (SD), thus giving advanced information about the ECG signals, such as instantaneous bandwidth, duration, and amplitude. Medical professionals may find it helpful to use morphological feature-based ML models to get insight into crucial clinical ECG features for early atrial arrhythmia prediction. Additionally, the generated models may help medical professionals choose individualized AF treatment and decrease misdiagnosis
Development of SiO2- CaF2 Based Oxyfluoride Glass-Ceramic for Up- Conversion Study
No full textUp-conversion (UC) is a non-linear optical process based on a two-photon mechanism which includes the energy conversion from the lower energy region (Near-infrared) to the higher energy (Visible) region. UC process has been used efficiently for various optical applications like solar cells, imaging, bio-sensing, and gene therapy. For a successful UC, the primary requirement is the presence of a low phonon host matrix in which rare- earth elements need to be embedded. Lanthanides like ytterbium (Yb3+) and Erbium (Er3+) are highly recommended for the UC process because of their simple ladder pattern energy level schemes. They exhibit luminescence through f-f transitions and high resistance to photo bleaching. Fluorides like PbF2, NaYF4, LaF3, and CaF2 are the most commonly used host for UC. However, the fluoride low phonon matrix has a problem of weathering that reduces the fluorescence efficiency. Embedded low phonon host in oxide glass matrix can solve this problem and increase the chemical stability. CaF2 has been chosen as a low phonon host in the present work, and silica has been chosen as an oxide matrix. Instead of making a core-shell particle that involves a complicated procedure, a simple sol-gel technique has been attempted for SiO2-CaF2 glass-ceramic nanoparticle synthesis. The concentration of CaF2 has been varied from 5 mol% to 25 mol%. Er3+ has been chosen as an activator, and Yb3+ has been chosen as a sensitizer. The amount of Yb3+ and Er3+ has also been varied to observe the effect of concentration on luminescence property. Further, in the same matrix, Na2O has been added to create non-bridging oxygen in the matrix. An increase in non-bridging oxygen results high refractive index and its effect on luminescence property has also been examined. All the glass-ceramic samples have been prepared by the sol-gel method. The effect of CaF2 addition and the Er3+/Yb3+ doping on the crystallization behavior has also been examined through the Differential thermal analysis (DTA) technique. The samples were heat-treated based on the DTA measurement to develop the CaF2 phase. Their morphology has been examined through the transmission electron microscope (TEM). All samples have been tested for their luminescence characteristics by exciting it by 980 nm laser. The target was set to obtained both green and red emissions. Most of the samples have shown both green and red luminescence. All the prepared samples' cell viability has been studied, which indicated more than 90% cell compatibility. The protein adsorption study of rare-earth-doped Up Conversion Nano Particles (UCNPs) revealed a lower adsorption rate due to surface charge repulsion. Therefore, the proposed synthesized nano glass- ceramic can be used for bio-imaging applications
Magnetic, Magnetodielectric, and Magnetoimpedance Correlation in Modified Brownmillerite KBiFe2O5
No full textThe materials with multiple responses to external stimuli facilitate use in novel device applications. In this regard, tuning dielectric or capacitance with a magnetic field is challenging and scientifically important for technological applications. The phenomenon of coupling between dielectric and magnetic properties in materials is known as the magnetodielectric (MD) effect. It is challenging to get above RT ferroic orderings and MD coupling in single-phase materials. KBiFe2O5 (KBFO) is a new, less explored, and recently discovered novel material belonging to the brownmillerite crystal (A2B2O5) family. The magnetoelectric, magnetodielectric, and magnetoimpedance analysis is entirely new and unexplored for KBFO. The dielectric, magnetic, magnetodielectric, and magnetoimpedance (MI) properties of parent KBFO and chemical doped samples are investigated. The present thesis is carried out systematically by studying the parent KBFO, the A-site doping with rare earth Holmium (Ho), the B-site doping of transition element Cobalt (Co), and the co-doping (Co and Ho) of rare earth and transition ion in both the sites of KBFO, respectively. The solid-state reaction route is used to synthesize KBiFe2O5, Co-doped KBiFe2(1-x)Co2xO5 (B-site), Ho-doped KBi(1-y)HoyFe2O5 (A-site), and KBi(1-y)HoyFe2(1-x)Co2xO5 (co-dope) {0 ≤ x = y ≤1} samples. The Rietveld refinement of powder X-ray diffraction (XRD) patterns of prepared samples are carried out, and the monoclinic phase with the P2/c space group is confirmed for all the samples. The absence of an impurity phase in XRD analysis confirms the phase purity of the prepared samples. Additionally, the RT Raman analysis further confirms the pure phase and the preferential site of dopants in KBFO. A detailed dielectric, magnetic, MD, and MI analysis with their correlation is established in parent KBFO over a wide temperature (10 K to 780 K) and magnetic field [-1.3 T (-13 kOe) to 1.3 (13 kOe) T]. The temperature-dependent magnetization (> 300 K) of KBFO shows an anomaly near dielectric transition (780 K), indicating the signature of MD coupling. The low-temperature magnetization ( 475 K) is prominent with Ho-doping. In the conduction process, the role of large-polaron hopping induced by translation motion is addressed via Ho-doping Finally, both the A-site and B-site of KBFO are doped with rare earth Ho and transition element Co simultaneously, and the magnetic, MD, and MI properties of KBFO are investigated. The RT magnetization values of the highest co doped x = y =15% (KBHFCO15) sample, such as MR, shows 20 times, and MS shows two times enhanced value compared to parent KBFO. The coercivity field shows a drop of 90% of the original value in the KBHFCO15 sample. Similarly, the magnetic anomaly near dielectric transition (TC ~ 775 K) indicates the signature of MD coupling in co-doped samples. The RT enhanced MD and ML coupling (inverted butterfly) strength of KBHFCO15 shows maximum values of 0.65% (MD%) and 1.25% (ML%), respectively. Similarly, the RT butterfly shaped MI coupling loops of the co-doped sample suggest the capacitive or the intrinsic origin behind the MD coupling. The MD coupling coefficient (γ) of parent KBFO (4%) increases with co-doping up to 11% in the KBHFCO15. Hence, the MD coupling in KBFO is shown at RT, and the RT MD coupling strength is enhanced through chemical substitutions. This study opens a new window into the unexplored research field of KBFO and provides a base for technological applications
Molecular Engineering of Efficient Light Harvesting Organic Antennas for Multitasking Organo EuIII Complexes: Design, Synthesis, and Photophysical Investigations
No full textThis thesis work mainly going to describe about the designing and synthesis of the ancillary ligands (antenna) for the Eu(III) based complexes and to investigate their application in red/white LEDs, sensors (temperature and vapoluminescence sensor) and bioimaging. Chapter 1 represents a general introduction of lanthanides and its unique spectral properties and it application in various fields. The importance of Eu(III) complexes, antenna effect of Dibenzoylmetahne DBM/ 2-Theonyl trifluoro acetone (TTA) and ancillary ligand, the lanthanides (specially Eu(III)) application in Red/white LED, temperature sensor vapoluminescence and bioimaging were systematically discussed. In addition, the recent progress of Eu(III) complexes for light emitting diodes (LEDs) and sensors were also being discussed. The main objective and significance of the present work of the thesis were documented. Chapter 2 describes the tailor-made molecular siblings induced single component bright white light emissive EuIII luminogens in EuIII systems. Such characteristics not been observed for analogue Eucomplex. It therefore demonstrates a proof-of-concept of applying molecular sibling as a choice of antenna for Eu-complexation and could modulate the complex emission. This research opens a path to discover new single component white light emissive luminogens through molecular siblings (proper choice of connectivity). This describes about both the phenanthroline (Phen) based ligands shown blue emission under 365nm UV lamp, whereas the corresponding complexes were shown red emission with tremendous color purity in solid and thin film. In solution (polar and non-polar), both the isomeric complexes were shown different emissive behaviour (red/white). Ligand to metal energy transfer mechanism was summarized thorough experimental and theoretical analysis. Glowing red LEDs were fabricated with different ratio of complex and PMMA with high LER values. Chapter 3 describes design and synthesis of two isomeric ligands for EuIII complexation. The purposelydesigned ancillary ligands show greenish-yellow emission in the solution as well as in solid state. However, the corresponding Eu-complex based mCF3 functionalized showed single component white light emission with balanced color purity, in contrast, the pCF3 functionalized Eu-complex showed pure red emission. The systematic solvatochromism study reveals that the Eu(TTA)3-TPA-DPA-mCF3 show multi-color /tunable emission with variable CIE color coordinates, in contrast Eu(TTA)3-TPA-DPA-pCF3 shows pure red emission. The mechanism suggests that the partial and complete energy transfer from ligand to Eu(III) ion is responsible and supported by theoretical as well as experimental study. Both the complexes have applied as a potential phosphor for red/white LEDs fabrication and particularly Eu(TTA)3-TPA-DPA-mCF3 is applied for white LEDs fabrication in conjugation with blue LED. The white LED produced superior white emission (CIE = 0.35, 0.34) with CRI = 86 %) and correlated color temperature (CCT) = 4645K, whereas near UV conjugated white LED showed CRI of 78 %. The red fabricated LED can be applied for visual detection of acid and bases vapors (act as electronic noses) from the environment due to emission swapping characteristics. Dual emission behavior of complex lead to study the thermometric property in higher temperature ranges Chapter 4 describe two efficient molecular EuIII based red-emitting complexes for SSL.The synthesized complexes harvest narrow-band red emission (FWHM ∼6 nm), which is extremely superficial to the human eyes, and lead to excellent chromatic saturation of the red spectral window. Significant efforts have been devoted to understand the energy transfer mechanism theoretically (by DFT) and experimentally. The highly bright full red color emissive LEDs were created by coupling red Eu(III) complexes as red phosphor with a near-UV LED chip (395 nm) operated at 20 mA forward bias, and the hybrid white LED spectra (yellow dye + Eu-complex) to show a pure white light emission with a low CCT (3704 K), high CRI (93), and CIE values of x = 0.33; y = 0.33. In addition, using Eu(TTA)-TPA-DPA-Ph as red components and TPA-DPA-Ph as the green component, hybrid white LEDs are created. The two-component hybrid white LED spectrum, which demonstrates pure white light emission with a low CCT (4499 K), a high CRI (87), and CIE values of x = 0.33; y = 0.36. All the synthesized red phosphors are found to be excellent for solidstate lighting applications Chapter 5 describes a series of unique EuIII complexes with the new class of ancillary neutral ligands named Thiabendazole (TBZ, N1 position functionalized with benzyl and N-alkylated carbazole (CBZ) pendants moiety) and DBM/TTA as anionic ligands. All the freshly synthesized TBZ-based Eu-complexes exhibited enormously outstanding narrow-band red emission due to ED transition (5D0→7F2), in solid, solution, and thin-film with high quantum yield. Theoretical analysis (TD-DFT) and experimental study (phosphoresce spectra) designate that the energy transfer (ET) from ligand to Eu(III) ion is comprehensive. The Eu(III) complexes are potentially applied for red LEDs and hybrid white LEDs fabrication. LEDs were made up by spreading Eu(III) over UV LED/blue LED chips conjugated with yellow dye with proper concentration. The fabricated red LEDs showed high luminous efficiency of radiation (LER) values and blue LED-based hybrid white LEDs showed superior performance with high color rendering index CRI (83%), CIE (x = 0.37, y = 0.34) close to NTSC standard. The Eu-complexes showed outstanding alterable on-off-on luminescence performance with the contact of acid-base vapors. Pure red emission of complexes gives rise to anti-counterfeiting applications. Thanks to an excellent spectroscopic exploration of the Eucomplexes (pure red emission), they are acting as a key model in the cytotoxicity study (less toxic) and bioimaging applications and perform a great job as cytoplasmic staining reagent due to intense red emission. Chapter 6 describes the new design strategy of Organo-EuIII based narrowband red-emitting phosphors which validate their energetic character in an unexpected performance in smart Red/white LEDs, sensing, and biomedical fields. In this chapter, a series of unique EuIII complexes have been synthesized with coumarin integrated with a new class of Phen/ TBZ based ancillary ligands and DBM/ TTA as an anionic ligand. All the Eu-complexes demonstrated outstanding red emission due to ED transition (5D0→7F2), in solid, solution, and thin film with high quantum yield (QY). Both theoretical analysis (TD-DFT) and experimental findings (phosphorescence emission at 77 K) describe that the energy transfer (ET) from the ligand’s triplet level to the Eu(III) ion is completely occurring. The Eu(III) complexes can potentially be used to fabricate the intense red LEDs and hybrid white LEDs. All the fabricated Red LEDs revealed high luminous efficiency of radiation (LER) values. The fabricated blue LED-based hybrid white LEDs displayed remarkable performance with low CCT (5634 K), high color rendering index CRI (88), and CIE values (x = 0.33; y = 0.342) for Eu(TTA)3Phen-UMB-C2. Furthermore, with the interaction of acid-base vapors, these Eu-complexes displayed good alterable on-off-on luminescence performance. A thorough investigation was conducted to evaluate the cell viability. The cells were viable at the concentration levels and employed in fluorescence imaging as potential biomarkers. Chapter 7 briefly describes new molecular design of two butterfly-shaped organic light harvesters (ancillary ligands L1, L2) to produce binuclear EuIII complexes (C1 and C2) and characterized by using various spectroscopy methods. The ligand with a simple benzene ring (L1) at the core showed bluish-green emission, in contrast, CF3 substituted ligand (L2) showed pure white light emission. Notably, under 390 nm excitation both the complexes showed sharp red emission in solid owing to (5D0→7F2) ED transition of Eu(III) ion at 612 nm (FWHM 3-4) with color purity 95-96%. The photophysical characteristics were investigated for both ligands and complexes. The europium complexes in the solid and liquid phases show intense red emissions due to the ED transitions of the Eu(III) ion. The solvatochromism investigation accounted for both the Eu(III) complexes in the non-polar solvent to polar solvent yielded a pure red emission. The synthesized butterfly-shaped organic chromophores and TTA as supportive ligands coordinated with Eu(III) ions can effectively assist energy transmission to the Eu(III) ion. Therefore, the ligand (L2) and two complexes (C1, C2) were devoted as a phosphor for red LEDs fabrication (1:10 (LER = 387/263). L2 acts as a single integrant white light-emissive phosphor and emits white light (CIE= 0.32, 0.37) by conjugating with the NUV chip. Chapter 8 deals the summary and conclusion as well as future perspective of the work. The present thesis works deals with rational design and synthesis of new and novel class of ancillary ligand and their corresponding EuIII complexes for white LEDs and sensor (temperature and vapoluminescence) and bioimaging applications. In addition, Eu molecular complexes also been explored for single component white light emitter based white LEDs. The observations and the conclusions derived from the present investigations are summarized in this chapter
Dynamics of Outward Foreign Direct Investment from BRICS: A Study of Home and Host Country Effects
No full textCapital is considered as an asset which is used to supply continuing production of goods and services for obtaining profits, and it helps to improve the economic conditions of a developing nation. The role of foreign capital is essential for economic development as it enlarges the competitiveness of the domestic market through transfer of technology, improving infrastructure, reducing unemployment, and involving in more productive activities. The “Foreign Direct Investment” (FDI) is a part of foreign capital which acts as a direct investment made by outsiders in the domestic market. It mainly considers international business operation in home countries. The objective of the research is to investigate the human and economic development in emerging countries. Also, the study will analyse the economic variables that determine the site choices of emerging countries for Outward Foreign Direct Investment (OFDI). Traditional interpretations about FDI are being challenged because of the sustained growth of OFDI in developing and emerging economies all around beginning of the twentieth century. The old theories are based on the experiences of large multinationals from developed and advanced economies and are not applicable to developing and emerging markets. As a result of this issue, there is disagreement about whether the existing theoretical concept of FDI, such as the International Organizational Framework, the Monopolies Advantages Theory, the Internalization Theory, and the Ownership-Location-Internalization (OLI) Concept, should be substituted by current models, maintained the same, or extended and modified to better match the setting of developing and emerging economies. Earlier studies, inspired by the troubling discussion, evaluated the explanatory capacity of traditional-OLI theory and innovative FDI theories Product cycle theory. However, such a strategy is revealed to be theoretically constrained (Buckley et al., 2007). To make traditional FDI theories more relevant for describing the quantity and type of outbound FDI from developing markets, the home country influence in contextual components, especially institutional environment is more important (Dunning and Lundan, 2008; Peng et al., 2008). The home country's macroeconomic and institutional environment, known as "L" advantages, can be used directly to enable OFDI flows. Indirectly, features of the home nation have a significant influence on determining the kind of "O" advantages that its firms have, which defines their capacity to invest overseas (Narula & Kodiyat, 2016). The current study will provide a conceptual framework that combines traditional economic considerations and identifies institutional distance. This study will restrict the sample areas for panel analysis by focusing on BRICS and India from 1990 to 2021 and 2012 to 2021, respectively. The research investigates four objectives to see the dynamic influence of OFDI in the BRICS. The initial goal is to explore the overall performance of OFDI as well as the changing pattern of OFDI. The primary objective is to investigate the achievement of OFDI as well as its changing pattern. The 2nd objective is investigated and explored the direct influence of outward FDI on both the host and the home nation. First and second objectives (2a) were addressed in the research, and the study followed an advanced methodology throughout the first chapter. In the first portion, the first chapter delivered an outline of the major trends and patterns of BRICS OFDI. Using five home countries as case studies, the second objective (2a) is to investigate the influence of macroeconomic performance on the amount of outward foreign direct investment (FDI) in home nations from 1990 to 2019. Using both fundamental and sophisticated methods, the study's findings conclude that most macroeconomic factors are relevant and positively influence outward FDI. Financial development is inversely connected with OFDI, showing that the countries' financial development does not stimulate external FDI, resulting in the countries' development deteriorating. The third chapter explores the influence of informal institutional distance and locational choice on home and host nations as it belongs to the second purpose of this research (2b). The paper uses the BRICS as a sample of investment home countries to examine the institutional effectiveness of OFDI in twenty host countries from 1990 to 2020. To determine the objective, the study used OFDI flows as a dependent variable acquired from UNCTAD and various independent factors for empirical analysis. The study employed a basic and augmented gravity model in which the traditional gravity components are positive and important, indicating that BRICS locational option is favourable. The augmented gravity approach discovered that the regulatory institutional distance (RID) that exists between home nations and selected host countries tends to block OFDI. On the other hand, normative and cognitive institutional distance frequently favour OFDI. The third goal of the research is to look at the linkage between technical innovation, outward FDI, and human capital in the BRICS from 1990 to 2020. This study employs Fixed-effects Regression and threshold Regression for static analysis, and FMOLS and 3SLS for robust results in the empirical portion. The study's outcomes reveal that all the determinants have long-term stable correlations. BRICS FDI has been found to be significantly related to home nation innovation performance, human resources, GDP per capita, and research intensity. Yet, the opposite would not be true for our model. Lastly, the fourth objective of the research investigates the overall performance of the economic variables of outward FDI analysis from India on both the country and firm levels in chapter five. The study investigates two types of analysis: country-level (level-1) and firm-level (level-2). After a diagnosis check, the research performs an augmented gravity analysis, where POLS and F-GLS results have little effect on the variables. The study used PPML to reduce heterogeneity and found that traditional gravity variables are relevant, showing that locational qualities of the host nation attract Indian OFDI. The PPML also discovered that institutional traits, such as regulatory and cognitive institutional distance, attract foreign investment. Nonetheless, there were no particularly noteworthy results from the cultural gap. Hence, language and cultural limitations likely explain India's low FDI to its top seven host nations. Level 2 of the study, which included 21 manufacturing firms, discovered that overall firm-level OFDI is increasing at a rather slow rate. The robust GMM findings indicated that profit and income are higher for Indian OFDI, but company size and foreign participation are unaffected
Facile Synthesis and Photocatalytic Application of MOF and MOF Derived Heterostructures for Activation of Atmospheric Molecules and Environmental Remediation
No full textIn this thesis, the synthesis and photocatalytic applications of metal organic framework (MOF) based binary and ternary heterostructure materials have been presented for visible light induced photodegradation of agrochemical contaminants and activation of atmospheric molecules to renewable energy and value-added chemicals. Initially, Zr-based MOF namely UiO-66 and amine functionalized UiO-66 are prepared by solvothermal and low temperature reflux route, respectively. The MOF materials are subsequently integrated with ternary metal sulphide nanostructures to prepare novel binary/ternary S-scheme heterostructure materials with improved optical absorption and enhanced photoelectochemical features. In an alternate approach, the MIL-68(In) MOF is also used as a sacrificial template to prepare hollow tubular In2O3 nanorods which are subsequently hybridized with mixed metal sulfides to prepare binary heterostructure materials. The comprehensive characterization of the composite materials is carried out to understand their structural, morphological, optical and photoelectrochemical properties. The photocatalytic application of the synthesized heterostructure materials is evaluated for photodegradation of agrochemical contaminants and activation of atmospheric molecules. The detailed mechanistic study and band position analysis of the composites are performed to understand the mechanism of photocatalytic action. A facile hydrothermal route has been developed for the preparation of a series of novel UiO-66/CdIn2S4 heterojunction materials containing finely dispersed UiO-66 spherical nanoparticles (20−40 nm) anchored over high aspect ratio CdIn2S4 nanosheets. The hierarchical materials exhibited unique structural, compositional as well as opto-electrical properties, which include high crystallinity, surface exposed reactive site, nanosized interfacial contact, strong absorption in visible region, rapid migration of charge carriers and high resistance to recombination. The optimal 30UiO-66/CIS photocatalyst exhibited excellent photocatalytic performances towards triclosan degradation (> 92 %) as well as H2 production (1.95 mmolg−1 h−1 with apparent conversion efficiency of 20.8%) with kapp value six and fourteen times higher than that of pure CIS, respectively. Radical trapping experiments suggested vigorous formation of reactive •O2− and •OH radicals in aqueous suspension of the UiO-66/CIS heterostructure. The pivotal role of e−, •O2− and •OH radicals has been described towards degradation of triclosan. Further, the UiO-66 MOF has been functionalized with amine chromophore to improve its visible light absorption characteristics. The UiO-66(-NH2) is used as a base semiconductor for construction of sulphur (S)-vacancy rich hierarchical UiO-66(–NH2)/CdIn2S4/CaIn2S4 ternary heterostructure materials by in-situ preferential growth of ultrathin CaIn2S4 nanosheets and CdIn2S4 nanorods in presence of UiO-66(–NH2) (UN) spherical nanoparticles. The photocatalytic efficacy of UiO-66(–NH2)/CdIn2S4/CaIn2S4 ternary hybrid material is explored for photocatalytic H2 evolution reaction and decontamination of asulam (ASM) herbicide. The development of S-vacancy facilitated interfacial charge carrier migration and reduced the recombination rate. The enhanced photocatalytic H2 production and ASM degradation could be ascribed to staggered band alignment between UiO−66(–NH2) (UN), CdIn2S4 (CDS) and CaIn2S4 (CAS), which support S-scheme charge channelization in the heterojunction. Due to its physio-chemical advantages, the optimal 15UN/CDS/CAS30 hybrid photocatalyst exhibited highest photocatalytic H2 evolution rate of 4931 μmolg−1h−1 with apparent conversion efficiency of 31.5% and ASM degradation > 93% (k = 0.02 min−1) under irradiation of visible light. The photocatalytic potential of amine functionalized UiO-66 MOF is further extended by construction of sulphur defect rich hierarchical UiO-66(-NH2)/CuInS2 n-p heterojunction system. Morphologically, the composite contained well dispersed UiO-66(-NH2) nanoparticles over the surface of hierarchical CuInS2 nanosheets. The hierarchical CuInS2 component showed surface sulfur defect leading to creation of more surface exposed active sites with improved absorption of visible light and augmented diffusion of charge carriers. Photocatalytic performance of prepared UiO-66(-NH2)/CuInS2 heterojunction materials has been explored for N2 fixation and O2 reduction reactions (ORR). The optimal UN66/CIS20 heterostructure photocatalyst exhibited outstanding N2 fixation and O2 reduction performances with yield of 398 and 4073 mol g-1 h-1 under visible light illumination, respectively. An S scheme charge migration pathway coupled with improved radical generation ability accounted for the superior N2 fixation and H2O2 production activity. The synthesis of hollow tubular In2O3 nanorods is accomplished by using MIL-68(In) metal-organic framework (MOF) as sacrificial template. The HT-In2O3 is subsequently integrated with MIIIn2S4 (MII: Ca, Mn, and Zn) nanosheets to prepare HT In2O3/MIIIn2S4 binary heterojunction materials. The targeted growth of ternary metal sulfide nanosheets on In2O3 is performed using a facile low-temperature reflux route. The efficiency of HT-In2O3/MIIIn2S4 binary heterojunctions has been studied for the photocatalytic H2, NH3, and H2O2 production. The ultrafast interfacial charge migration, better photoexcited charge separation, and significantly improved photocatalytic activity could be attributed to the narrow band gap energy of the MIIIn2S4 and S-scheme electron migration mechanism between In2O3 and MIIIn2S4 components in the heterostructures. Among the HT-In2O3/MIIIn2S4 (1:1) hetrostructures, the HT-In2O3/ZnIn2S4 (1:1) photocatalyst displayed the highest H2, NH3, and H2O2 generation (5331, 870, and 5716 μmol g−1 h−1) with conversion efficiency of 34%, 6.5%, and 0.291%, respectively. This study provides a comprehensive analysis on how the coupling of three different d0, d5, and d10 ternary metal chalcogenides MIIIn2S4 with HT-In2O3 affects the photocatalytic H2, NH3, and H2O2 production
Biomechanical Modelling and Biodynamic Response Analysis of Seated Occupants Under Whole-body Vibration
No full textSince the dawn of the industrial age, workplace vibration has significantly impacted people's ability to work comfortably. In general, supporting surface vibration exposes drivers and passengers of vehicles and machines to whole-body vibration (WBV). In the past, some researchers used real people as test subjects to determine their biomechanical characteristics (mass, stiffness and damping) and predict their biodynamic responses (seat-to-head transmissibility (STHT), apparent mass (AM) and driving point mechanical impedance (DPMI)). Discomfort, musculoskeletal disorders, fatigue, structural alterations in the lumbar area, back pain, muscular pain, disc degeneration, and annoyance are typical risks humans experience due to WBV. To get past these problems, researchers strive for an alternative to experimentation that can generate comparable results. The first step in achieving this would be to create a biomechanical model with a human-like structure and enforce enough complexity to replicate or depict real people. The segmental vibration transmissibility ratio, power absorbed, ride comfort analysis, and damage estimation is a few uses of biomechanical models. These valuable benefits inspired the author to create biomechanical models that accurately imitate the biodynamic responses of actual humans in a seated posture. Regular experiments on humans are impractical, unethical, and dangerous because they are highly sophisticated, complex dynamic structures. As a result, a 10-dofs (degrees of freedom) lumped parameter biomechanical model without backrest support in seated posture is created for quantitative and qualitative analysis. The human body is symmetrically divided about the sagittal plane into a head, thorax, abdomen, pelvis, upper arm, forearm, and hand, without a backrest and lower limbs, while the steering wheel is ignored in the analysis. Mass, springs, and dampers are sequentially connected to these body segments to imitate humankind's structure. Newton's second law on each segment is implemented by presuming that each segment has one degree of freedom in a vertical direction. The equation of motion for each segment is derived and grouped to obtain global equations of motion (EOMs). The global EOMs obtained in the time domain are converted into the frequency domain using fast Fourier Transformation (FFT). The mechanical parameters (mass, stiffness, and damping) utilized to define the biomechanical model are optimized through the firefly algorithm (FA). A multi-objective function is acquired based on the biodynamic responses (STHT, AM, & DPMI). The objective function minimized the sum of squares error between the analytical responses and referred experimental data under symmetrical constraints. The effectiveness of the optimized parameters is calculated in terms of goodness of fit (GOF) values. The optimized parameters have shown tremendous performance in terms of GOF values. Also, the impact of these parameters on the peak value of STHT is analyzed. The subsequent work examines the impact of backrest support on biodynamic responses. The biomechanical model created in the previous section is changed to include backrest support, and a 20-dofs multi-body (MB) is suggested. Here each segment has 2-dofs (vertical & fore-and-aft). The influence of vertical vibration on the fore-and-aft direction and vice versa is incorporated with the help of cross-coupling stiffness and damping parameters to overcome the limitations of 10-dofs biomechanical model. Newton’s-II law is utilized to obtain elemental and global systems EOMs. The global EOMs contain both vertical and fore-and-aft parameters, including cross-coupled parameters. The segmental transmissibility (seat to head, seat to back, and seat to hip) ratios are included in the objective function. The biomechanical parameters are optimized and compared with the experimental studies. The segmental transmissibility curves are plotted by changing the backrest inclination angle to incorporate the effect of different backrest inclination angles. The segmental transmissibility comparison shows reasonably good agreement between the analytical responses at different backrest inclination angles and experimental responses. A sensitive analysis has been carried out to identify the optimized parameters' effect on STHT. Later the proposed model is coupled to the 7-dofs full car model and performed ride comfort study under harmonic excitation. The aforementioned model is then modified to include the influence of lower limbs by including thighs, legs, and feet, and a 32-dofs MB model named the passenger model is proposed. A multi-objective function is derived based on two biodynamic responses (STHT and AM), magnitude and phase information. By minimizing the sum squares error between the experimental and analytical response, the characteristic parameters of the passenger model are optimized with FA. The effect of the backrest is studied by changing the backrest angle. Later the transmissibility values from the seat to upper body segments (head, thorax, abdomen, and pelvis) are identified. Also, the ride comfort analysis is carried out by integrating with a full-car model. Afterward, the passenger model is updated by holding the steering wheel to include the steering action, and a 32-dofs MB model termed the driver model is proposed. With FA, the characteristic parameters of the driver model are optimized by reducing the sum squares error between the experimental and analytical STHT and AM responses. Upon comparison, it is observed that the STHT and AM responses acquired at 240 backrest angle show good agreement under low frequency (11 Hz). From sensitivity analysis, it is observed that the parameters at the pelvis and lumbar support regions significantly impact STHT for the driver model, just as in the passenger model. The transmissibility ratio (TR) in the critical organs (head, thorax, abdomen, and pelvis) reveals that the input vibration has the most significant impact on the head and the least on the abdomen at the resonance frequency. The work done in this thesis primarily focuses on the development of biomechanical modelling, as well as the analysis and assessment of biodynamic responses of seated occupants. The new aspect of the constructed model is how closely it resembles the actual human being
Community Participation in School Management: A Case of Two Tribal Villages in India
No full textOne of India’s flagship programmes relating to education is the Sarva Shiksha Abhiyan (SSA) (Universalization of Elementary Education), which mandates free, compulsory, and equitable primary education to all children. The study aimed at understanding whether a decentralized school management system makes it easier for the tribal community to participate in the School Management Committee (SMC) through open dialogue to ensure better school governance and access to quality education for the children. The SMC provides parents with a forum to represent themselves as key players in managing the school. School Management Committee meetings facilitate open communication and awareness among underrepresented parents to negotiate their rights and entitlements in a local setting. Thus, communication is employed on two levels: to disseminate knowledge and to engage ordinary people in a dialogue that leads to collaboration. Participatory development communication, which includes ideas like “information as means of awareness and open dialogue as a means of collective action” provides the theoretical underpinning for this study. The research employed a qualitative case study design to obtain in-depth data from SSA management staff at all levels, as well as parents, students and community members in two schools of two tribal dominated villages in Sundargarh district of Odisha. The research was split into four phases to ensure thorough coverage of the three objectives. The results showed that even while parents made up a sizable portion of the school committee, they were clueless about the responsibilities that came with their membership. Although several co-learning sessions are mandated by SSA to encourage open dialogue, neither the school nor the parents get involved. An information dissemination intervention strategy called Information, Awareness, Motivation and Action (IAMA), involving a few local educated youths, parents, teachers, and students, was designed and implemented in two tribal villages to address the issue. Interpersonal communication helped to build relationships between the teachers, literate youth volunteers, and community members. The sense of ‘commonness and homogenization’ process established trust on both sides that further helped to change the perception, attitude, and beliefs of the community that they are not passive participants in the process of education for their children. The study concludes that educational reforms have usually been top–down processes; no doubt the objectives have always been good, but they fail at the ground level because of the overarching disconnect. One positive impact that was observed was that local success stories motivate the parents to care for their child’s career. A mobilization process led by local success stories can strengthen the social capital, and then only it can create new success stories, not by force but by choice