Performance Assessment of Futuristic Novel TFET Architectures for Ternary CMOS and Biosensor Applications

With the advancement of the electronics industry, there is a growing need for increased integration levels and cost-effective technologies. With the constant downscaling of CMOS technology, high-speed MOS devices have been developed that are ideal for analog/RF applications. It is crucial to have systems that prioritize low distortion and linearity as fundamental components of their design. But nowadays, due to the downscaling, the CMOS technology faces many challenges regarding short-channel effects (SCEs). So, this resulted in requirement for new device architecture and design. One prospective candidate for enhancing the performance of scaled CMOS integrated circuits is a tunnel field effect transistor (TFET). TFET functions through the mechanism of band-to-band tunneling (BTBT), which can obtain low OFF current (IOFF), steep subthreshold swing (SS), and high ION/IOFF ratio at reduced supply voltage but has low ON current (ION), and ambipolar conduction occurs. TFET can be used for many low-power applications. The performance improves when we increase the control over the channel. So, the double gate TFET (DGTFET) outperforms single gate TFET. Different DGTFET structures have been modeled and simulated with SiO2/high-k stacked gate oxide. The work function and pocket engineering also help to enhance the device's performance. In modified gate oxide double gate TFET (MGO DGTFET), the gate oxide is carefully placed at an optimized depth within the channel, leading to decrease in IOFF and ambipolar current. There is enhancement in ION; eventually, ION/IOFF ratio improves. In triple metal extended source double gate vertical TFET (TM-ES-DGVTFET), the channel is perpendicular to the source, which increments the probability of lateral and vertical tunneling. As a result, there is an enhancement in ION, SS, and ION/IOFF ratio. Different applications of TFET have also been investigated. A vertical TFET with a pocket (VP-TFET) has been used to design a ternary inverter. In VP- TFET a thin silicon epitaxial layer is present between the source and gate oxide. P+ pocket is present in channel close to source region. In VP-TFET vertical tunneling occurs along with lateral tunneling. A hump is created at the channel region because of the presence of a P+ pocket in the channel. In VP-TFET channel-channel and source-channel tunneling occurs and a ternary inverter has been designed. The ternary inverter is a multi-valued logic (MVL). MVL helps to reduce power density on a chip. Ternary logic, which has three steady states ("0", "1", and "2") instead of binary logic, which has two states ("0", and "1"), may store more data in the same amount of space. This directly correlates to miniature chip size and helps reduce the total number of interconnects and pins used in a VLSI chip design. TFET-based ternary logic can be advantageous in spiking neural networks and neuromorphic computing. A vertical TFET has been used to detect the biomolecules. In vertical TFET-based biosensor (VB) a thin silicon epitaxial layer is present between the source and gate oxide. The cavity is etched beneath the gate electrode at the left side of HfO2 for biomolecule immobilization. The dielectric constant is altered by the immobilization of biomolecules within the carved cavities, which were formerly filled with air. This modification changes device's electrical characteristics. In VB, vertical and lateral tunneling occurs, which increases the tunneling carriers, the current increases, and eventually, the sensitivity of the biosensor is enhanced. The Poc-MGOTFET-based biosensor is used to detect breast cancer (BC) cell lines. The gate oxide of Poc-MGOTFET-based biosensor is carefully placed at an optimized depth within the channel. The SiO2 layer within the nanogap cavity serves as an adhesive layer for the cell lines. The N+ pocket is incorporated at the source side and the gate is an extended structure. The cavity is etched beneath the gate electrode at the left side of HfO2 for biomolecule immobilization. Breast tissue included healthy (MCF-10A) and cancerous (MCF-7, T47D, Hs578T, and MDA-MB-231) cell lines. The detection method of the biosensor is based on differences in the dielectric constants of different BC cell types. The dielectric constant is altered by immobilizing the cancer cells within the carved cavities, formerly filled with air. This modification changes the device's electrical characteristics. Sensitivity analysis considers drain current, transconductance, ION/IOFF ratio, and VT. Maximum sensitivity is observed in T47D (k = 32) BC cells because it has a higher dielectric constant. The selectivity is calculated between the healthy and cancerous BC cell lines. The effect of irregular cell line confined in the cavity has been investigated to evaluate the ability of the device to detect BC cell lines. The Poc-MGOTFET-based biosensor can detect breast cancer biomarker (C-erb-B-2). The effective charge caused by the existence of C-erbB-2 biomarker in serum/saliva is utilized as the interfacial charge of the device for detecting C-erbB-2 biomarker. Sensitivity analysis considered ION/IOFF ratio. The significant increase in sensitivity, by a factor of 106 μg/L, is attributed to the influence of interfacial charges caused by different C-erbB-2 biomarker quantities on biosensor's sensitivity (as determined by ION/IOFF ratio)

Efficient 3D-Localization Algorithms in Underwater Acoustic Sensor Network Employing Optimization Methods

The Underwater Acoustic Sensor Network (UASN) is a specialized type of wireless sensor network designed for underwater environments. The underwater acoustic sensor network is a fundamental source for ocean exploration. The potential applications of UASN include seismic imaging, disaster prevention, mine reconnaissance, pollution monitoring, exploration of natural resources, military surveillance, etc. To acquire accurate results, implementing all applications of underwater sensor networks requires an adequate network connection and communication technology. The precise placement of underwater sensor nodes must be identified to communicate effectively. The sensor nodes in UASN are intermittently deployed randomly in the three-dimensional scenario. Determining the three-dimensional localization of underwater sensor nodes is one of the most challenging tasks as compared to two dimensional. This motivates us to propose a three-dimensional localization algorithm in USAN. In this thesis, we proposed three range-free localization algorithms. These proposed algorithms are based on the compensation of the stratification effect for the improvement of the performance parameters such as localization accuracy, ranging accuracy, convergence rate, and execution time. Then proposed the fourth algorithm for clustering of localized sensor nodes. The simulation, experimental validation, and analysis are performed employing a Python environment to evaluate the performance of the proposed schemes. Firstly, To fulfill the objective, a localization algorithm I-LASP (Improvement of localization algorithm for compensating stratification effect based on extended improved particle swarm optimization technique) is proposed in three-dimensional UASN, based on compensation of stratification effect for the improvement of the performance parameters such as localization accuracy, ranging accuracy, convergence rate and execution time. To compute the accurate position of target nodes, the EIPSO (Extended improved PSO) technique is applied, and the degree of coplanarity is checked before the calculation of distance among nodes in order to get the accurate location of target nodes (unknown nodes). The Centroid method is used to initialize the position of sensor nodes, and the ray theory method is used to compensate the stratification effect on the layered ocean water. The proposed algorithm is compared to the existing LASP, Std PSO, and GNA-ESSP (Gauss-newton algorithm-extended sound speed profile) localization algorithm. The proposed algorithm provides 34.50%, 38.87%, and 42.66% of high accuracy in terms of localization with low density of target sensor nodes and 37.96%, 29.58%, and 50.77% high accuracy in terms of localization with a high density of target sensor nodes respectively. The proposed algorithm is compared with LASP, GNA-ESSP, and TDOA to obtain 66.84%, 71.14%, and 86.13% of high accuracy in terms of ranging with low density of target sensor nodes and 42.34%, 89.00%, and 95.08% high accuracy in terms of ranging with a high density of target sensor nodes respectively. Experimental results represent that the proposed algorithm obtains better performance in terms of localization accuracy, ranging accuracy, root mean square error, normalized localization error, execution time, and convergence rate. To further enhance the localization accuracy, an effective localization approach for compensating the stratification effect based on a revamped underwater grey wolf optimization method (RLCS-IUGWOM) is presented in the thesis. To determine the precise geographic position of underwater sensor nodes, the nodes in the 3D-UASN are firstly distributed haphazardly, employing an amalgamation of centroid-based localization and the ray theory approach. Subsequently, the coplanarity of the underwater sensor nodes is analyzed. An improved underwater grey wolf optimization method (IUGWOM) is employed subsequently after the estimation of the position of unknown nodes to acquire the precise position and compensate the stratification effect. The mathematical comparative analysis between the I-LASP and the presented algorithm is accomplished. In 3D-UASN for both low and high-density zones, the RLCS-IUGWOM obtains localization accuracy of 72.50% and 78.92%, respectively and ranging accuracy of 72.50% and 78.92%, respectively. The outcomes of the mathematical simulation reveal that the proposed algorithm surpasses the existing algorithm in terms of localization and range accuracy in both low and high-density zones in 3D-UASN. It also exhibits outstanding efficiency regarding RMSE, NLE, computation time, and convergence rate. Next, we have proposed an efficient localization algorithm to compensate for the stratification effect based on an improved underwater salp swarm optimization technique (LAS-IUSSOT). To compute the location of sensor nodes with high accuracy, the nodes are initially randomly deployed in 3D-UASN. After that, the hybridization of centroid-based localization and the ray theory technique is used, and then the degree of coplanarity is analyzed among the underwater sensor nodes. Then, the location of unknown nodes is computed using IUSSOT (Improved underwater salp swarm optimization technique) to obtain the optimized location and compensate the impact of the stratification. The comparison of the simulation results of the existing algorithm and the proposed algorithm is performed. The LAS-IUSSOT achieves 40.46% and 28.00% accuracy in terms of localization of underwater sensor nodes for both the sparse and dense regions in 3D-UASN. The LAS-IUSSOT achieves 49.39% and 62.57% accuracy in terms of ranging of underwater sensor nodes for both the sparse and dense regions in 3D-UASN. Simulation results illustrate that the proposed algorithm outperforms the existing algorithm in terms of localization and ranging accuracy in both sparse and dense regions in 3D-UASN, RMSE, NLE, computation time, and convergence rate. Finally, We analyze from the existing literature that the two most critical requirements for the application’s proper operation are the accurate knowledge of sensor node locations and the efficient transmission of accurate underwater sensor node information to the base station with efficient energy consumption. To accomplish the objective we proposed Energy Efficient Localization Based on the LEACH-Beacon and Reinforced node (EELBL-BR) algorithm which satisfies both the requirements in 3D-UASN.The proposed algorithm considers the deployment and computation of accurate location of sensor nodes in the underwater environment by applying I-LASP(Improvement of localization algorithm for compensating stratification effect based on extended improved particle swarm optimization technique) for 3D environment. It performs clustering of sensor nodes for enhancing network lifetime using three different types of nodes such as beacon, reinforced and member nodes. The proposed clustering LEACH-BR (Low-Energy Adaptive Clustering Hierarchy-Beacon and Reinforced nodes)algorithm is based upon the LEACH algorithm, which provides accurate location of all the sensor nodes and improves energy consumption and reliability in the underwater environment. The result shows that the proposed algorithm EELBL-BR, considering both beacon and reinforced nodes, provides the improvement in the number of alive nodes, reduction in the number of dead nodes, reduction in energy consumption and enhances residual energy in the UASN by 68.90%,51.91%,51.47%and 68.12% respectively with respect to the number of rounds as compared to that of the existing algorithm by authors and thus outperforms the existing algorithm

Design of High Power Interleaved Boost Converter with Enhanced Efficiency and Equal Current Distribution using Novel Control Algorithms

In electric vehicle (EV) applications, the interleaved boost converter (IBC) can be used in place of a conventional boost converter (CBC) to improve efficiency and reduce the size of the drive train. This is due to the inherent property of ripple cancellation, and equal current distribution of IBC. However, to reduce the size, improve efficiency, and maintain equal current distribution in each phase of IBC proper analysis of IBC is required. The ripple current analysis plays a vital role in choosing the inductor and filter capacitors to minimize the size of an IBC. This research work presents, a simple and generalized formula for the input ripple current of N phase IBC. Also, presented the design of the inductor with two different core materials as Ferrite and Sendust. The thermal analysis of IGBT modules to select an appropriate heat sink has been presented. The minimum phase selection has been done by considering several constraints such as the area product of the core, discrete components size based on ripple analysis, cost of all components, and converter efficiency. By considering all these constraints a 7.5 kW 3 − ϕ IBC converter is designed in the laboratory. The IBC has a low-efficiency problem compared with CBC when it is operated in the region of low to medium load conditions. This is due to the fact that at low to medium load conditions, the switching and core losses are more dominant than conduction losses in the IBC. Therefore, an efficiency improvement is necessary for IBC under low to medium load conditions, when the number of phases increases. In the present research work, to achieve this objective, an efficiency-based rotating phase-shedding control algorithm has been implemented for a 3 − ϕ IBC with an automatic phase selection. In the case of phase number selection, the required unknown parameter value i.e. “equivalent phase resistance” has been estimated online in order to improve phase shedding performance. The other problem of the IBC is, the unequal current distribution of individual phases is caused by the variation in the resistive parasitics of passive and active components of each phase. This results in thermal imbalance, uneven aging, and efficiency degradation of IBC. This problem has been addressed in previous works, and numerous current sharing control techniques have been developed. However, in order to generate the required control effort from these control schemes for compensating the uneven current sharing, a variety of sophisticated methods were adopted. These methods increase the design complexity of the controller proportional to the increased number of phases. In this research work, a new current balance algorithm (CBA) is implemented by adaptively changing the duty ratio with a simple voltage mode control (VMC) to reduce control effort and design complexity in order to achieve equal current distribution in each phase of IBC. The present research also investigates the control and energy management of IBC-based active configured battery and ultracapacitor (UC)-based hybrid energy storage systems (HESS). In general, the battery/UC HESS power allocation is done by a frequency-sharing algorithm by allotting high-frequency components of load demand to UC and low-frequency components to the battery. The frequency-based power sharing batter/UC HESS with UC loop (conventional EMA) restricts the UC operation to a reference voltage to prevent it from overcharging undercharging. This leads to a very narrow utilization of the UC voltage range. However, UC voltage can safely be varied from zero to maximum rated voltage. In the present research work, UC boundary-based frequency power sharing approach has been used for UC charging/discharging. The EMA has been modified in such a way that the UC voltage loop activated only when the UC voltage crosses its operating boundary limits. An experimental prototype of the system is designed and the proposed EMA has been tested in the different operating regions for validation

Red/Orange-Red Emitting Phosphors for Solid State Lightings: Structure-Compositions-Property-Correlations

Highly efficient narrowband red-emitting phosphors based on oxides remain a significant challenge for white LED applications. The current thesis addresses the design, synthesis, and photophysical analyses of Eu3+-activated oxide-based narrowband red-emitting, Sm3+/Eu3+ red/deep-red emitting phosphors, and trivalent Eu molecular complexes. These materials are investigated for their potential applications in solid-state lighting (including white LEDs and light sources for plant growth). The study methodically examines the relationships between the structure, composition, and properties of these phosphors. Chapter 1 introduces solid-state lighting, phosphor materials, the luminescence process involved, and white light-emitting diodes. Literature surveys of recently developed Eu3+ and Sm3+-based red/deep-red emitters for solid-state lighting were also discussed. Additionally, a brief introduction to latent fingerprint detection and security ink is provided. The importance of trivalent Europium molecular complexes for white light emission, along with a review of recent literature, is also covered. This chapter concludes by summarizing the primary goals and significance of the thesis. Chapter 2 describes the Eu3+ luminescence in Na2La4(WO4)7 and its application in solid-state lighting. All NLW:xEu3+ phosphors exhibited a sharp red emission at ~616 nm due to the ED transition (5D0 → 7F2) under 394 nm excitation. In addition, the Na2La3.2(WO4)7:0.8Eu3+ phosphor demonstrated a high color purity of 96.79% and IQE of 83.8%. A temperature-dependent PL study revealed the thermal stability of the phosphor as 69.75% at 423 K. To assess their practical applicability, red and white LEDs were fabricated using the synthesized phosphor. The EL spectrum of the red LED displayed intense red emission, while the white LED exhibited remarkable performance with a high CRI of 80 and a low CCT of 5730 K. These Eu3+ doped red phosphors can also be utilized for latent fingerprint applications. Moreover, a series of Sm3+ doped and Sm3+/Eu3+ co- doped NLW phosphors were synthesized and investigated for their optical properties. Red/deep-red LEDs were fabricated using Sm3+ co-doped Eu3+-activated phosphors for potential applications in plant growth. Chapter 3 describes the optical characteristics of Eu3+ doped Na2Y4(WO4)7 red emitters. The synthesized phosphors exhibited intense red-light emission (5D0 →7F2, ED transition) due to the non-centrosymmetric site occupation of Eu3+ ions within the crystal lattice. The Abstract solid solution between tungstate and molybdate groups enhanced the emission intensity. The thermal stability and internal quantum efficiency of the phosphor were found to be ~75.54% (at 423K) and 88%, respectively, under excitation at 395 nm. Furthermore, solid solution phosphors were developed to enhance the QE, which increased to 91.3%. The hybrid white LED exhibited superior white light emission with a high CRI of 80 and a low CCT of 5730 K. These values were further improved (CRI-81, CCT-4274 K) when the WLED was fabricated using the most efficient solid solution phosphor, Na2Y2.2Eu1.8(WO4)3(MoO4)4. Additionally, Sm3+ and Eu3+ co-doped deep-red phosphors were synthesized and studied for their optical properties for plant growth. The emission from the fabricated LED (Sm3+ and Eu3+ co-doped) completely covers the phytochrome PR absorption spectrum. Chapter 4 describes zero concentration quenching in Eu3+-activated Na5Ln(WO4)4 [Ln = Y, Gd] red-emitting phosphors with a scheelite structure. The emission spectra were dominated by the ED transition (5D0 → 7F2) under UV/NUV excitation, indicating the non- centrosymmetric site occupancy of the activator ions in the lattice. This was further confirmed by AR analysis and Judd-Ofelt parameters. For fully Eu3+ substituted phosphors, the color purity and IQE were found to be approximately 97.05% and 85.6%, respectively. In a high-temperature environment (150 ℃), Na5Eu(WO4)4 retained 69.03% of its initial emission intensity under 395 nm excitation, while the solid solution phosphor Na5Eu(WO4)1.5(MoO4)2.5 retained 85.56% of its initial emission intensity at 466 nm excitation. The fabricated white LEDs exhibited good CRI (81) and CCT (5734 K) values. In addition to lighting applications, the synthesized red phosphors demonstrated potential applicability in areas, such as LFP detection and anti-counterfeiting. Furthermore, Sm3+/Eu3+ co-doped Na5Ln(WO4)4 phosphors were developed to explore their potential use in plant growth applications as red/deep-red LEDs. Chapter 5 describes the trivalent Eu3+ luminescence in Li2La4(MoO4)7 and its applications in various fields. Either 395 nm near-UV light or 465 nm UV light can efficiently excite these synthesized phosphors, producing red light with a prominent wavelength at 616 nm. The optimal phosphor composition for high concentration quenching was identified as Li2La4(MoO4)7:1.8Eu3+, which achieved a high color purity (CP) of 97.28% and an internal quantum efficiency (IQE) of 89.6%. The Eu3+ emission from this phosphor exhibited excellent thermal stability, retaining 81.75% of its initial intensity at 423 K. To further enhance photophysical properties, solid solution phosphors were synthesized, Abstract increasing the IQE and thermal stability to 92.5% and 86.12%, respectively. When combined with a yellow organic dye and a blue LED chip, the red component enhanced the CRI and CCT of customizable white light emitting diodes (WLEDs). The WLED fabricated using the Li2La4(MoO4)7:1.8Eu3+ red phosphor demonstrated pure white light emission with a high CRI of 83 and a low CCT of 4925 K. These values were further improved to a CRI of 86 and a CCT of 5371 K when using the Li2La2.2Eu1.8(MoO4)4(WO4)3 solid solution phosphor. Prospective uses of the phosphors that are now being synthesized include security applications (to identify latent fingerprints and in the anti-counterfeiting). Additionally, Eu3+/Sm3+ co-doped red/deep red emitting phosphors were synthesized, and their photophysical properties were extensively studied for potential use in fabricating red/deep-red LEDs as a light source to promote plant growth. Chapter 6 describes the computation-aided design, synthesis, and photophysical study of N1-functionalized phenanthrol-imidazole based Eu(III) molecular complexes. Two ancillary ligands were synthesized, and their effects on the photophysical properties of the respective Eu(III) complexes were studied. Both ligands exhibited blue emission, where as their respective Eu(III) complexes displayed pure red emission. Detailed photophysical and electroluminescence analyses were conducted. In contrast to DBM complexes, TTA based complexes demonstrated a longer lifetime. The fabrication of red LED was achieved by integrating red-emissive Eu(III) complexes with near-UV LED chips. Using the synthesized complexes, white LEDs were fabricated by mixing them with a yellow dye and coating the mixture onto the surface of blue LED chips. The Eu-complexes currently under research have also demonstrated outstanding reversible on-off-on luminescence behavior on exposure to acid-base vapors. Chapter 7 briefly summarizes the results obtained from the investigations and the major conclusions drawn from these studies. Furthermore, it outlines the future scope of the present study

Mechanistic Insights on Phagosome-Lysosome Fusion by 4 (Benzyloxy)Phenol and its Effect on Intracellular Mycobacteria in Human Macrophages

Drug-resistant tuberculosis (TB) outbreak has emerged as a global public health crisis. Therefore, new and innovative therapeutic options like host-directed therapies (HDTs) through novel modulators are urgently required to overcome the challenges associated with TB. In the present study, we have investigated the anti-mycobacterial effect of 4- (Benzyloxy)phenol (4-BOP). Cell-viability assay asserted that 50 μM of 4-BOP was not cytotoxic to Phorbol 12- myristate 13-acetate (PMA) differentiated THP-1 (dTHP-1) cells. It was observed that 4-BOP activates p53 expression by hindering its association with KDM1A. Increased ROS, intracellular Ca2+, and phagosome-lysosome fusion were also observed upon 4-BOP treatment. We further demonstrate that 4-BOP-mediated enhanced ROS production is mediated by acetylation of p53. 4-BOP-mediated killing of intracellular mycobacteria was abolished in the presence of specific p53, ROS, Ca2+, and phagosome- lysosome fusion inhibitors like PFT-α, NAC, BAPTA-AM, and W7, respectively. Next, we dissected the immunomodulatory regulation of 4-BOP in various cytokines. We found that 4-BOP treatment increases IL-35 production in uninfected and mycobacterial-infected dTHP-1 cells, which regulates the phosphorylation of JAK1 and STAT3. While blocking JAK1/STAT3 activation with Baricitinib and Stattic reduced 4-BOP-induced ROS and Ca2+ production, impairing phagosome-lysosome fusion and enhancing mycobacterial survival. Furthermore, siRNA-mediated silencing of IL-35 receptors (IL-12Rβ2 and gp130) disrupted JAK1/STAT3 signaling, reduced ROS-Ca2+-phagosome fusion, and increased intracellular mycobacterial burden in 4-BOP-treated cells. Inhibition of p53 using PFT-α reduced IL-35 production and JAK1/STAT3 phosphorylation, indicating that IL-35 activation by 4-BOP is p53-dependent. These findings highlight the role of 4-BOP in regulating p53 to eliminate intracellular mycobacteria associated with IL-35-mediated phagosome-lysosome fusion

Development of Sodium Alginate/chitosan Based Nano-composite Three-dimensional Printed Scaffolds for Bone Tissue Regeneration

A functionalized scaffold with desired physico-chemical, structural and biological characteristics is a pre-requisite to regenerate damaged bone tissue. The present work aimed to develop sodium alginate (SA) and chitosan (CH) based nano-composite scaffold by three- dimensional (3D) printing technique for bone tissue engineering (BTE). To this end, 3D printed SA/CH blend scaffolds with different compositions were fabricated. The scaffolds possess open pore microstructures and interconnected pores with appropriate pore size as evident from scanning electron microscopic image analysis. The Fourier-transform-infrared spectroscopic analysis revealed polyelectrolyte complex (PEC) formation when SA and CH were blended, that can provide superior scaffold surface for cell attachment, proliferation, and offers ideal microenvironment for neo tissue formation. Among the scaffolds, SA/CH with 60:40 ratio exhibited controlled swelling and degradation pattern, higher tensile strength (0.387 ± 0.015 MPa) and superior apatite layer deposition ability. The scaffolds are hydrophilic and biocompatible as evident from contact angle, protein adsorption, MTT and cell attachment assessment. Thus, the developed 3D printed scaffold with SA/CH (60/40) is proven to be a suitable substrate for tissue engineering application. The biological property of the SA/CH scaffold was improved by blending with 0-15% (v/v) gelatin (GE) thereby promotes cell adhesion, proliferation and differentiation. The resulting tri-polymer complex was used to fabricate 3D printed SA/CH/GE matrices. The microfibrous porous scaffolds having 383-419μm pore size were revealed by SEM study. X- ray diffraction (XRD) and FTIR analyses confirmed their amorphous nature and the strong electrostatic interactions among the polymer functional groups forming polyelectrolyte complexes that may improve mechanical property and structural stability during in vivo application. The scaffolds have controlled swelling and degradation pattern, hydrophilic characteristics favorable for bone tissue regeneration. An enhanced tensile strength was obtained due to increased stiffness of SA/CH scaffolds upon addition of GE. An enhanced protein adsorption and apatite layer formation confirmed the ability of SA/CH/GE scaffolds for higher cellular adhesion and bone like environment during tissue regeneration process. MTT assay, and confocal microscopy analysis exposed a significant enhancement in cell adhesion, metabolic activity, proliferation and biomineralization activity. Furthermore, SA/CH containing 15% GE (SA/CH/GE15) has shown superior performance indicating their suitability for bone tissue engineering application. For the improvement of osteogenic property, Bioglass (Bg) and nMgO-loaded Bg nanoparticles were synthesized and characterised. The synthesized nBg was further introduced into SA/CH/GE15 polymeric network to achieve natural bone mimetic property containing the desired inorganic and organic phase. The osteogenic and other cell supportive property of the SA/CH/GE15 scaffold were enhanced by reinforcing nBg with different concentration (0.3%- 0.5 %w/v) in the polymeric network resulting in composite bioinks which were used to fabricate 3D printed SA/CH/GE15/nBg. The nano-composite scaffold have microfibrous open pore structure with pore size range of 419±102μm to 554±68 μm. The hydrophilicity of the scaffold was improved on addition of nBg with decrease in contact angle. The scaffolds exhibited controlled swelling and degradation behavior desired for BTE and enhanced compressive strength with increased nBg content in the SA/CH/GE15 scaffold and the values were 1324.63±32.71 kPa and 1942.33±37.56 kPa for SA/CH/GE15/nBg0.4 and SA/CH/GE15/nBg0.5 which are desired for cancellous bone regeneration. An enhanced bioactivity and protein adsorption was achieved with nBg incorporated scaffolds. MTT assay with cultured bone osteosarcoma cells on the composite scaffolds showed that SA/CH/GE15/nBg scaffolds are cytocompatible. An improved cell supportive activity (cell attachment and proliferation) was shown by nBg loaded scaffold as evident from SEM and confocal image analysis. In comparison, a higher ALP activity representing higher osteogenic property was shown by SA/CH/GE15 containing nBg0.4. The effect of reinforcement of the synthesized nMgBg in the SA/CH/GE15 network on the osteogenic ability of the 3D printed scaffold was investigated. The reinforcement of nMgBg at 0.4% and 0.5% w/v concentration with SA/CH/GE15 polymeric network did not affect the hydrophilicity, swelling, degradation and protein adsorption activity of the scaffold. The presence of Mg promoted apatite layer formation over the scaffold as revealed by in-vitro bioactivity test and SA/CH/GE15 nMg1Bg0.4 showed the highest apatite formation. In-vitro cell studies suggested that low Mg containing scaffolds SA/CH/GE15/nMg1Bg0.4 is favorable for osteoblast proliferation. The scaffold showed superior ALP and biomineralization activity than the scaffolds containing nBg and nMg2Bg. Overall, SA/CH/GE15/nMg1Bg0.4 was demonstrated as the most potential substrate that can pave the way for bone tissue regeneration in future

Vicinal Diols as C2 Precursor in N & O- Containing Heteroaryl Synthesis

Vicinal diols exhibit a unique combination of properties, including high reactivity, selective oxidation, chiral recognition, hydrophilicity, and biodegradability, making them valuable in various fields. Their versatility in synthesis, biological relevance, pharmaceutical importance, and environmental applications make them useful in multiple industries. Specifically, vicinal diols are employed as anti-corrosion agents, lubricants, surfactants, fragrances and flavors, and agrochemicals. Aliphatic vicinal diols play a crucial role in cellular signaling, metabolism, and antioxidant mechanisms, inhibiting glycosidases and regulating carbohydrate metabolism, while also enhancing adhesive properties and coating durability. Furthermore, aliphatic vicinal diols serve as precursors for polyurethanes, polyesters, and epoxy resins, aid in degrading pollutants like pesticides and heavy metals, and facilitate the synthesis of functionalized nanomaterials. In pharmaceutical applications, aliphatic vicinal diols act as versatile intermediates in organic synthesis, enabling asymmetric synthesis and supporting the design and development of new drugs, including antibiotics, antivirals, and anticancer agents. Oxygen and nitrogen- containing heteroaryl compounds are indispensable in various fields due to their unique properties, including high electron affinity, conductivity, photoluminescence, biocompatibility, and stability. Their biological activity, versatility in synthesis, industrial utility, and pharmaceutical importance make them highly sought after. These compounds play a vital role in pharmaceuticals as antibiotics (quinolones, macrolides), antivirals (HIV, hepatitis), anticancer agents (kinase inhibitors), anti-inflammatory agents, and CNS active compounds (anxiolytics, antidepressants). Additionally, they are utilized in agrochemicals as herbicides (pyridines, quinolines), insecticides (neonicotinoids), and fungicides (azoles). In materials science, heteroaryls are employed as conductive polymers (polythiophenes), organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), and fuel cells. They also find applications in biotechnology such as DNA-binding agents, RNA-targeting compounds, gene delivery systems, and biosensors. Furthermore, heteroaryls participate in asymmetric catalysis, oxidation, and reduction reactions and serve as starting materials in complex molecule synthesis. Some heteroaryl compounds include indole, furan, pyrrole, pyridines, quinolines, isoquinolines, pyrazines, oxazoles, thiazoles, imidazoles, pyrazole and triazoles. In this thesis our objective is to synthesize heteroaryl compounds utilizing vicinal diol as a C2 building block. Chapter 1. Vicinal diols in organic synthesis: A brief review This chapter summarizes the significance and synthetic utility of vicinal diols in heterocyclic chemistry. Vicinal diols possess unique attributes, making them valuable across various disciplines. They serve as anti-corrosion agents, lubricants, and surfactants, and as precursors for polyurethanes and epoxy resins. Vicinal diols find applications in polymer synthesis, as protecting groups, and as a C2 precursor for heterocyclic synthesis, including indoles, pyrroles, imidazolones, pyrazines, piperazines, quinoxalines, and quinolines. Chapter 2. Oxidative coupling of vicinal diols and 2-amino-1,4-naphthoquinone for the synthesis of pyrrolonaphthoquinones An iron-catalyzed oxidative coupling reaction between 1,2-diols and 2- aminonaphthoquinones has been developed, facilitating the regioselective production of benzo[f]indole-4,9-diones under mild conditions. This efficient process involves the oxidation of vicinal diols to α-hydroxy carbonyl compounds, followed by concurrent N-C and C-C bond formation. with 2-amino naphthoquinone. Chapter 3. Access to 2,3-unsubstituted imidazo[2,1-b][1,3]benzothiazole using ethylene glycol as a C2 precursor and subsequent regioselective C3 functionalization Synthesis of imidazo[2,1-b [1,3]benzothiazoles by oxidative coupling of 2- aminobenzothiazoles with vicinal diol was reported. Expectedly, a combination of potassium persulfate and TEMPO oxidized ethylene glycol to α-hydroxy acetaldehyde, which coupled with 2-aminobenzothiazole to afford 2,3- nsubstituted imidazo[2,1- b][1,3]benzothiazoles. The later was exploited as a reliable handle to access 3-substituted imidazo[2,1-b][1,3]benzothiazoles regioselectively Chapter 4. Transition-metal-free access to substituted furans and pyrroles using vicinal diol as C2-precursor A transition metal-free oxidative method to synthesize substituted furans from β- ketoanilides and vicinal diols was reported. This approach accommodates a wide range of functional groups (e.g., halogens, methoxy, methyl, nitro) and enables the regioselective formation of 2,3-disubstituted and 2,3,5-trisubstituted furans via base-promoted oxidative C-C and C-O bond formation. Additionally, substituted pyrroles were synthesized regioselectively using β-ketoenamines, and vicinal diols as C2 precursors. Chapter 5. Vicinal diols as C2 precursor in oxidative ring annulation to form fused Furans This phapter describes a novel synthetic pathway for the metal-free acid-catalyzed oxidative ring annulation of vicinal diols with beta-naphthols, yielding naphtho[2,1- b]furans. Additionally, we successfully applied this catalytic system to achieve a one-pot synthesis of avicequinone B from 2-hydroxy naphthoquinone, resulting in a remarkable yield. The presented methodology offers a convenient and efficient metal-free synthetic pathway for the preparation of diverse biologically active organic compounds

Exploring Molecular Intricacy: Development of Facile Carbon- Heteroatom Bonds via Oxidative Dearomatization Reactions (ODRs)

In the last few decades, oxidative dearomatization has been widely recognized as an attractive and straightforward transformation for the development of a high level of molecular complexity, as it provides an efficient method to derive three dimensional architectures from simple planar achiral substrates. Attempts to dearomatize arenols employing non-metallic reagents have been confined mostly to hypervalent iodine reagents, being to generate mostly spiro-lactones, spiro- ethers, and spiro-amines. In this context, our group with the continued interest in dearomative transformations, we started our journey through the exploration of an oxidative dearomative methodology by employing quaternary ammonium tribromides. It has been envisaged that spiro[4.5] and [5.5]trienones, the core structures of many naturally occurring compounds, can be directly accessed from dearomative spiro-annulation of ynones, biaryl ynones and appropriately substituted phenols bearing a pendant side chain. The thesis chapters highlight spiro-annulation via energetically demanding dearomatization reactions promoted by either visible-light or Lewis acid or quaternary ammonium tribromides for the formation of structurally complex spirocyles along with several carbon-heteratom bond generations. The thesis presently divided into the following six chapters. Chapter 1. Bromine induced spirocyclization of biaryl ynones facilitated the synthesis of spiro[5.5]trienones suitable for extended functionality at the C(3´) position. Herein, a step- economic photo-oxidative brominative carbannulation of biaryl ynones employing ammonium bromide and riboflavin tetraacetate (RFTA) have been developed. The reactivity between distal phenyl C-H activated ortho-annulation and dearomative ipso-annulation are well exemplified. The eminent features of the methodology include metal-free, external additive free, low-loading photocatalyst (0.1 mol%) and use of simple precursor. Chapter 2. In chapter 2, we conceptualized an efficient radical cyclization approach for the synthesis of SCF3, SAr, SO2Ar and COAr featured spirocyclic [4.5] and [5.5] trienones between biaryls and ArSO2H or ArCOCO2H in presence of RFTA as a photocatalyst and ArSSAr or AgSCF3 without photocatalyst via energetically demanding dearomatization pathway under visible-light catalysis. The unprecedented photo-excited charge transfer complex with biaryl tethered ynone provides a way to promote S-centered radical generation. Success of this approach was the wide range of sulfur centered radical generation/addition to the organic molecules/consecutive cyclization under mild conditions. Chapter 3. Sulfinyls are valuable structural moieties in the development of new pharmaceuticals and agrochemicals. In this chapter 3 of the thesis, we disclose a straightforward synthesis of functionalized spirotrienones proceeding via an unprecedented BF3.Et2O promoted spirocyclization of biaryl ynones in presence of aryl sulfinic acid. The economic availability of the BF3.Et2O to carry out transformations in bulk scale along with its further application towards the synthesis of dibenzocyclohepten-5-ones delivers a unique opportunity to utilize it in various synthetic directions. Chapter 4. An extended period of rapid growth in annulated arene heterocyles via radical route has occurred in the last few decades, leading to the synthesis of several naturally occurring compounds or biologically significant building blocks. Herein, we discover a smooth interface for the synthesis of spiro[4.5] and [5.5]trienones, a simple brominative (PART I) and thiolative (PART II) addition of alkynoates by oxidative spirocyclization. A simple protocol which leads to exclusive formation of C(3´)bromo spiro[4.5]trienones and C(3´)thiomethyl spiro[5.5]trienones from biaryl substrate, where it endures a regio-selective spirocyclization in presence of corresponding electrophiles. The methodology features a broad scope of biaryl substrates into challenging spirocyclic cores with good functional group tolerance and operates under mild metal-free conditions. Chapter 4.1. In this sub-chapter, a convenient and generalized method for in situ tribromide generation was studied and with this strategy we developed a wide variety of brominative spiro[4.5] and [5.5]trienones. Figure 4. Graphical abstract for chapter 4.1 Chapter 4.2. In this sub-chapter, an efficient and metal-free dearomative cationic approach is achieved for the synthesis of thiomethylated spiro[5.5]trienones from biaryl ynones and 1,1,2- trimethyldisulfan-1-ium as a source of thiomethyl cation. Chapter 5. A wide range of spirolactams were synthesized with good yields and regio-selectivity through a step-up oxidative dearomatization of readily available arenols tethered to ester and primary amines in presence of less explored quaternary ammonium tribromides (QATBs). The probable reaction mechanism associated with tribromide triggered dearomatization reaction has been forecasted with a series of control experiments, time-dependent HRMS and DFT studies to establish the reaction mechanism 6. In this chapter, biologically valuable isocoumarins were synthesized with broad substrate scope in high yields and excellent regio-selectivity through oxidative dearomatization of easily prepared o-alkynylbenzoates and o-alkynylbenzamides employing quaternary ammonium tribromides under metal-free conditions. Besides halocyclization, this intramolecular cyclization proceeds smoothly with several chalcogen-based electrophiles for the generation of C-S, C-Se and C-Te bonds. Interestingly, under certain condition, isochromenones were obtained in presence of diorganyl disulfides with PTATB

Modulation of Electrical Properties of RF Sputtered Tantalum Oxide Based Thin Films for High-k dielectric Applications

In the past decade, significant research efforts have focused on integrating high-k dielectric materials to replace traditional low-k dielectrics like SiO2. Among these materials, tantalum oxide (Ta2O5) has garnered substantial attention and appears particularly promising due to its high dielectric constant (≈25-30), relatively large energy bandgap (~4.5 eV), better amorphous to crystallization temperatures, and good thermal stability in contact with both silicon and metal gates. These exceptional material properties have made Ta2O5 highly attractive for use as a gate dielectric in Metal-Oxide-Semiconductor Field- Effect Transistors (MOSFETs). Furthermore, resistive switching in metal-oxide-metal structures fabricated using Ta2O5 thin films have demonstrated excellent memory effects, making it a suitable candidate for advanced memristor device applications. Integrating these devices into a monolithic structure, such as a one transistor one resistor (1T-1R) configuration, could potentially achieve high-speed operation, high storage density, and low power consumption. This advancement is facilitated by the use of multifunctional high-k dielectric materials like Ta2O5. Thin films of Ta2O5 have been produced using the radio frequency (RF) magnetron sputtering method. The study investigates the influence of sputtering parameters such as RF power, sputtering pressure, Ar/O2 gas flow ratio, and substrate temperature on the structural, morphological, and electrical properties of the films. The optimizing conditions are found to be RF power of 150 W, sputtering pressure of 1.0 × 10-2 mbar, Ar/O2 gas flow ratio of 3:2 and substrate temperature of 300 °C. Additionally, the impact of conventional annealing and rapid thermal annealing (RTA) at different process conditions, (temperature and duration) on the properties of Ta2O5 films is examined. 800 °C for conventional annealing and 750 °C for 10 min duration for RTA Process were found to be the optimal post-deposition treatment. At these optimal conditions, high dielectric constant, low leakage current, low oxide charge density, and low interface state density are observed. Doped versions of Ta2O5 films, incorporating Zr, and Hf, are synthesized on silicon substrates using RF co-sputtering. The dopant concentration is adjusted by varying the RF power applied to the dopant target while maintaining the RF power of the Ta target at an optimized level. To further modulate the electrical properties of the Ta2O5 thin film, a ZrO2 and HfO2 stacking layer was incorporated with different thickness configurations. An initial investigation was conducted to examine the resistive switching (RS) behavior of Ta2O5 films using a metal/insulating/metal (MIM) structure for memory device applications. This research work aims to investigate the enhanced RS characteristics of Ta2O5 films with varying different process parameter. Specifically, the study explores the effects of dopants and stack layer on the switching behavior of the as-deposited and modified Ta2O5 films. To investigate the structural, morphological, elemental and electrical properties of RF sputtered Ta2O5 thin film with various growth process parameters different characterization techniques were used. A Rigaku Ultima IV multipurpose X-ray diffractometer was used to study the structural properties of all the Ta2O5 based thin film. Nova Nano SEM/EFI field emission scanning electron microscope (EFSEM) was used to performed the morphological study on all sputtered Ta2O5 based samples, while X-ray photoelectron spectroscopy (XPS) from Omicron technology was used to study the compositional analyses of the sputtered films. Park XE7 atomic force microscope (AFM) was used to determine the roughness of the films. Al/Ta2O5/Si MOS capacitors were fabricated to study the electrical properties of the RF sputtered Ta2O5 films. Capacitance- voltage (C-V) and current-voltage (I-V) measurements were performed on the MOS structures using an Agilent E4980A precision LCR meter and a Keithley 6487 Picoammeter, respectively. Further, current-voltage measurements were performed on the metal-insulator-metal (MIM) structures using a Keithley 2410 sourcemeter to study the resistive switching behavior of the sputtered films

Development of Ni-based Hybrid Coatings by Electrodeposition/ Laser Cladding Followed by Ultrasonic Shot Peening

The ultrasonic shot peening (USSP) technique is a reliable post-treatment method for various industrial components to prevent functional failures by imparting residual compressive stresses, texturing, roughness modification, surface nano-crystallization, and compaction. This study aims to develop hybrid Ni-based coatings and cladding on mild steel using Electrodeposition/laser cladding (LC) and USSP techniques. Morphological studies reveal that the coatings and claddings exhibit enhanced closure of pores/cracks, increased micro-hardness, and improved corrosion and scratch resistance after peening. XRD analysis confirms the presence of compressive residual stresses, as well as grain refinement and texturing effects after the peening. After undergoing USSP treatment, the average surface roughness increased by up to 6 μm due to the formation of dimples. Furthermore, compared to the Ni/Ni-TiO2/Ni-Cr coatings and claddings, the hybrid coatings exhibit a hydrophobic character linked to improved corrosion resistance and better in-depth roughness profiles. Furthermore, the research endeavors to improve their mechanical and electrochemical properties by employing USSP's varied process parameters in a hybrid approach