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Efficient 3D-Localization Algorithms in Underwater Acoustic Sensor Network Employing Optimization Methods
No full textThe 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
Advanced Control Strategies for Efficient Power Management in Dc Microgrid With Hybrid Energy Storage Systems
No full textThe renewable energy sources (RESs) have recently been considered viable alternatives for conventional generation systems. RESs, such as wind and solar are feasible options for reducing greenhouse gas emissions. This work primarily focuses on developing suitable voltage controllers for the power management control loop that can effectively regulate the DC bus voltage in the DC microgrid (DCMG). The selection of control parameters is also challenging and time-consuming. Parameter selection ambiguity can diminish the dynamic response of power systems and lead to instability. Hence, soft computational methods are commonly employed to improve dynamic responsiveness under changing the load conditions. A well-known PID controller is applied in the voltage-controlled loop to stabilize the DC bus voltage and ensure adequate power flow in PV- battery-integrated DCMG. An inherent limitation of the PID controller is its reduced stability and poor system performance in the presence of disturbances. Therefore, the two-degree of freedom integrated proportional integral (2-DOF FOPID +PI) is designed and implemented as a voltage controller in the control loop of power management scheme (PMS) to regulate the DC bus voltage and power flow effectively in PV–battery integrated DCMG. To confer the viability of the proposed 2-DOF FOPID +PI controller, its performance is compared with other literature-based conventional controllers (PID, FOPID, 2-DOF PID, 2-DOF FOPID). The parameters of the controller mentioned above are tuned by modified salp swarm algorithm (MSSA) algorithm. To demonstrate the effectiveness of the MSSA algorithm, its performance is tested and compared to other algorithms, such as salp swarm algorithm (SSA) and genetic algorithm (GA). MATLAB simulation and OPAL-RT platform are used to examine the system's performance under different case studies (under variable load and generation). The limitation of PV-battery integrated DCMG is that the power supply may not be reliable due to the inherent intermittency of PV energy. Therefore, wind energy sources have been integrated with PV to improve the system's reliability. Another limitation is that the MSSA-optimized 2-DOF FOPID +PI controller-based PMS cannot effectively regulate the DC bus voltage during the initial transient portion. To address the above limitation, the three-degree of freedom integrated fractional order PID (3-DOF FOPID) controller is designed and implemented as a voltage controller in the PMS control loop, that can suppress the noise characteristic and improve the voltage stability. The modified sine cosine algorithm (m-SCA) algorithm is used to optimize the dynamic response of the 3-DOF FOPID controller and optimize its control parameters. A comparative study has been done between 2-DOF FOPID +PI controller-based PMS and proposed 3-DOF FOPID controller-based PMS in the MATLAB environment. However, the 3-DOF FOPID controller could not effectively regulate higher voltage variation, potentially posing issues for sensitive equipment. To alleviate this limitation, a hybrid fuzzy integrated fractional-order cascaded PDF (1+PI) (HFFOC PDF (1+PI)) controller is proposed and implemented as a voltage controller in the PMS control loop. A hybrid modified sine cosine integrated pattern search (m-SCA-PS) algorithm is used to tune the parameters of the proposed controller to improve the system's dynamic response. The proposed HFFOC PDF (1+PI) controller-based PMS, 3-DOF FOPID controller-based PMS, and 2-DOF FOPID + PI controller-based PMS were compared in the MATLAB environment. An extensive robustness study in the proposed DCMG system has been carried out against stochastic and real-time generation variations like solar irradiation, temperature, and wind speed. There are multiple limitations associated with a single energy storage system. The batteries cannot rapidly supply energy during high-power demand applications due to their lower power densities. The excessive power requirements may cause more stress on batteries, resulting in accelerated deterioration and shortened lifespan. Therefore, a supercapacitor (SC) has been integrated with the battery, that can reduce the battery's stress levels and improve the system's reliability. To manage the power flow in a hybrid energy storage system (HESS) integrated DCMG, the multistage FOPID controller is proposed and implemented as a voltage controller in the PMS control loop. Harris' Hawks optimization (HHO) algorithm is used to optimize the control parameters of the multistage FOPID controller. The proposed PMS analyses with different cases are performed in the MATLAB environment and the real- time OPAL-RT platform. The multistage FOPID controller-based PMS could not effectively reduce the settling time of DC bus voltage, resulting in a slow response to load or power generation fluctuations. The hybrid adaptive fuzzy integrated multistage FOPID (HAFI multistage FOPID) controller is proposed and implemented as a voltage controller in the PMS control loop to alleviate this limitation. A hybrid chaotic HHO integrated PS algorithm is used to tune the parameters of the HAFI multistage FOPID controller to improve the system's dynamic response. The proposed hybrid adaptive fuzzy integrated multistage FOPID (HAFI multistage FOPID) controller-based PMS and multistage FOPID controller-based PMS is compared in the MATLAB environment. The HAFI multistage FOPID controller could not effectively regulate higher voltage variation during load or weather variations, potentially posing issues for sensitive equipment. Therefore, a hybrid artificial neural network-model predictive controller (hybrid ANN-MPC controller) based PMS is proposed to alleviate the above-mentioned limitations. The proposed PMS has a faster settling time, that can improve the reliability and stability of the system and provide superior load management. The proposed hybrid model predictive controller driven artificial neural network (MPC driven ANN) based PMS is compared with HAFI multistage FOPID controller-based PMS and multistage FOPID controller-based PMS in MATLAB/Simulink environment. An extensive robustness study of the DCMG system is conducted against the parametric uncertainty and real-time variation in solar irradiation, solar temperature, and wind speed. The efficacy of the proposed hybrid MPC driven ANN –based PMS has been evaluated by using computational studies and real-time OPAL-RT across different operating conditions
Design and Synthesis of Polymeric Nanocomposite Materials for Efficient Removal of Cr(VI) from Aqueous Solutions
No full textWater pollution has become a significant global issue due to the increased presence of heavy metal ions and various pollutants in aquatic systems giving a serious threat to living organisms. Cr(VI) is highly toxic among heavy metal pollutants which affects millions of people worldwide. Even minimal exposure to Cr(VI) above permissible limit can cause a number of diseases which include nausea, diarrhea, respiratory disorders, DNA mutations and genetic information damage, which can lead to malignant tumors and failure of kidney. So, the remediation of Cr(VI) is a main focus for the researchers. This thesis presents a detailed studies on the synthesis of novel polymeric nanocomposite materials designed for the adsorptive sequestration of hexavalent chromium. Four number of novel polymeric nanocomposites mainly polypyrrole zirconium phosphate, polyaniline zirconium tungstophosphate, polyaniline yttrium phosphate and polypyrrole modified layer double hydroxides are synthesized by incorporating pyrrole, aniline as an organic component and zirconium phosphate, zirconium tungstophosphate, yttrium phosphate, layer double hydroxides as inorganic components. The assessment of the structural, morphological, textural functional, and thermal stability of the synthesized materials is conducted using various analytical techniques like XRD, TEM, FESEM, EDX, Raman spectroscopy, TGA-DTA, FTIR, N2 sorption isotherms, Zeta potential measurements, XPS and other instrumental analyses. A polypyrrole modified zirconium phosphate (PPY-ZrPO4) nanocomposite is synthesized by in situ oxidative polymerization process and used to remove hexavalent chromium from synthetic solution. The pseudo-second-order kinetic is the best fitted model for Cr(VI) adsorption with maximum adsorption capacity of 62.5 mg g-1 following the Langmuir isotherm model. The spontaneity, endothermic nature and feasibility of this adsorption process is confirmed from thermodynamic data. The adsorption with partial reduction of Cr(VI) to Cr(III) are the basic mechanism being followed in this adsorption process. The surface functional group of -N= and -NH- are responsible for Cr(VI) reduction. A novel nanocomposite of polyaniline zirconium tungstophosphate (PANI-ZrWPO4) is synthesized following an in situ oxidative polymerization reaction and subsequently used to remove Cr(VI) from aqueous solution. The TEM and FESEM images revealed that polyaniline are decorated on the surface of the ZrWPO4. The experimental data are best fitted to Langmuir isotherm model as compared to other model with a maximum uptake capacity of 71.4 mg g-1. The XPS spectra confirmed the adsorption and partial Cr(VI) reduction to Cr(III) through in situ chemical reduction. The regeneration efficiency of PANI-ZrWPO4 is able to remove around 80% of Cr(VI) even after five cycles. Polyaniline-modified yttrium phosphate (PANI-YPO4) nanocomposites is synthesized following oxidative polymerization process in in-situ condition and used to remove Cr(VI) from both wastewater as well as aqueous solutions. Morphological analysis by FESEM and TEM revealed a flower-like structure of the nanocomposite. This adsorption is governed by the kinetics models of pseudo-second-order and Langmuir isotherm model having an uptake capacity of 91.0 mg g-1. The adsorption mechanism involves the electrostatic attraction among anions of Cr(VI) and the PANI-YPO4 nanocomposite, accompanied by the in situ chemical reduction of hexavalent chromium to less toxic trivalent chromium. The nanocomposite shows successful regeneration and reuse up to five cycles with 85% removal efficiency. Furthermore, the PANI-YPO4 nanocomposite exhibited impressive adsorption efficiency of 99% for real chromium wastewater solutions containing Cr(VI). The NiFe-layer double hydroxide is prepared following hydrothermal process and subsequently synthesized polypyrrole modified NiFe-layer double hydroxide through in situ oxidative polymerization process and used to remove Cr(VI) by batch mode experiment. The experimental data are best fitted to pseudo second order kinetics model as compared to other kinetics model and Langmuir isotherm model having a maximum uptake capacity of 96.7 mg g-1. The spontaneity and endothermic nature are evidenced by the thermodynamic study. The adsorption mechanism is due to adsorption, reduction, ion exchange in the region of interlayer of nanocomposite, hydrogen bonding on the surface and electrostatic interaction. The material shows more than 85% regeneration ability even after five cycles
Synthesis of Slag-Waste Glass Binary Geopolymer and Its Application as a Sustainable Stabilizing Material
No full textConcrete is the second most consumed material after water. A higher dependency on cement concrete tremendously enhanced the demand and production of Portland cement. Despite its higher demand, the production process of cement has severe environmental issues, including depletion of natural resources, higher energy consumption, and emission of greenhouse gases. Geopolymer is a green binder proposed as an alternative to conventional binders. Any industrial by-product possessing amorphous aluminosilicate components could be used to produce geopolymers through alkali-activation. It has gathered significant attention from researchers due to its better performance and eco-friendly nature. While significant research has been carried out to synthesize geopolymer binders from industrial-based aluminosilicates, recyclable aluminosilicates are also being used as precursors for synthesizing geopolymer binders. Waste glass is one of the recyclable materials with high silica component used for preparing geopolymer binders in combination with alumina-based materials. Hence, in the current study, laboratory investigation was made to synthesize slag-waste glass geopolymer and assess its suitability as a sustainable stabilizer for geotechnical applications. In the first phase of laboratory investigation, the geopolymer binder was synthesized using slag and glass powder (GP) as precursors and sodium hydroxide (NaOH) as an alkali activator. The solubility of silicon, aluminum, and calcium ions from the precursors in the NaOH solution was examined. The fresh and hardened properties of the geopolymer were assessed at different GP contents (0%, 10%, 20%, 30%, and 40%), NaOH concentrations (2 M, 4 M, 6 M, 8 M, and 10 M) and liquid alkali activator-to-solid binder (L/S) ratios (0.25, 0.30, 0.35, 0.40, and 0.45). Mineralogical and microstructural studies were made to substantiate the changes observed in fresh and hardened properties. The effect of synthesis parameters on the compressive strength (CS) was statistically analyzed by developing a statistical model. The CS of slag-GP geopolymer at various temperatures (-15 °C to 90 °C) and curing durations (1 day to 90 days), as well as the effect of initial-temperature curing under sealed and humid conditions, were explored. The strength development in submerged and autoclave curing conditions was also assessed. Further, the durability of geopolymer mortar against high-temperature exposure (HTE) of 200 °C to 1000 °C, wet-dry (W-D) and freeze-thaw (F-T) cycles, water slaking, surface abrasion, alkali-silica reaction (ASR) expansion, and chemical attacks were determined and compared with cement mortar. In the second phase of the investigation, pond ash (PA) was stabilized with slag-GP geopolymer, cement, and lime. The effect of different additive contents (3%, 6%, 9%, 12%, and 15%) on the hydro-mechanical properties of the stabilized PA was assessed. The hydro-mechanical properties include compaction characteristics, unconfined compressive strength (UCS), indirect tensile strength (ITS), California bearing ratio (CBR), hydraulic conductivity, and compressibility index. The durability of the 28-day cured stabilized PA against W-D and F- T cycles, water slaking, water immersion, capillary action, and dispersion was studied. The effect of delayed compaction on the engineering properties of the stabilized PA was also examined. Mineralogical and microstructural analysis were assessed and correlated with strength and durability properties. In addition, leachable concentrations of different metallic ions from stabilized PA were examined. The experimental results indicated that the solubility of the precursors depends on the alkali concentration and reactivity behavior of the precursors. Slag has a higher solubility in NaOH solution compared to GP. The normal consistency of slag-GP geopolymer was increased with an increase in GP content and NaOH concentration. However, the setting period and workability of the geopolymer paste were reduced with increased GP content and NaOH concentration. The final setting period was shortened by 56 min, and the flow diameter was reduced by 26.57% when GP content increased from 0% to 40% at 6 M NaOH concentration. Based on 28-day CS, an optimum NaOH concentration of 8 M and an optimum L/S ratio of 0.35 were observed for slag-based geopolymer. With GP inclusion, the NaOH requirement was reduced by up to 50% due to the availability of alkali cations in GP. At higher GP contents (>20%), the rise of Si/Al, Na/Al, and Si/Ca molar ratios beyond their ideal range causes a decline in the CS of slag-GP geopolymer. However, the resistance to soundness and drying shrinkage improved as GP content increased. The key reaction phases observed in slag-GP geopolymers are sodium alumina silicate hydrate (N-A-S-H), calcium alumina silicate hydrate (C-A-S-H), sodium alumina silicate (N-A-S), and calcium silicate hydrate (C-S-H). A non-linear statistical model developed with GP content, alkali concentration, and L/S ratio as input variables predicts the CS with an R-square of 0.9072. At ambient temperature (30 °C) and prolonged curing (90 days), higher strength was observed at 10% GP content. However, a higher dose of GP is beneficial for specimens cured at elevated temperatures (45 °C to 60 °C). Little improvement in strength with the curing period was noticed for the specimens cured at temperatures below the freezing point of water. Under humid curing, slag-GP geopolymers attained dense microstructure, whereas micro-cracks were observed in the specimens cured under dry environments. Submerged curing in alkali solutions achieved better strength compared to curing in normal and saline water. Autoclave curing showed rapid strength gain due to the advancement in the geopolymer mechanism. Moreover, the proposed analytical models predict the CS well at different GP contents, curing temperatures, and curing durations. The slag-GP binary geopolymer at 10% GP content has better durability against harsh environments, such as HTE, W-T and F-T cycles, water slaking, surface abrasion, and chemical attacks, than slag-based geopolymer and cement. The GP-rich geopolymer (20% to 40% GP) showed better structural integrity after exposure to higher temperatures (> 700 °C) due to the filling of micro-pores with molten glass particles. However, ASR expansion was found to increase marginally with GP contents. In addition, laboratory studies show that the PA can be efficiently stabilized with synthesized slag-GP geopolymer. The PA stabilized with slag-GP geopolymers achieved higher strength properties such as UCS, ITS, and CBR, as well as lower hydraulic conductivity and compressibility index compared to cement and lime-stabilized PA. Further, a denser and more compact microstructure of geopolymer-stabilized specimens achieved excellent durability than cement and lime stabilized specimens. Based on strength and durability properties, it is confirmed that PA stabilized with 6% geopolymer can be effectively used as a cementitious base in flexible pavements as per IRC 37-2018 and cementitious subbase in rigid pavements as per IRC 58-2015. With delayed compaction, the dry density and strength properties were reduced, whereas the hydraulic conductivity and compressibility index increased. At 15% geopolymer content, the compacted dry density was reduced by 11.92%, 18.74%, and 22.62% after 6 h, 24 h, and 72 h delay periods, respectively. Similarly, the UCS was reduced by 18.64%, 54.86%, and 67.35%, respectively. Whereas the hydraulic conductivity and compressibility index values increased by 3.61, 6.59, and 9.61 times, respectively, and by 15.87%, 33.89%, and 55.43%, respectively. The formation and deposition of cementitious products and agglomeration during delay periods lead to poor compaction and deteriorate the mechanical performance. The leachable concentration of iron (Fe), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), nickel (Ni), and copper (Cu) from the stabilized PA was within the threshold limits of WHO and IS 10500-2012 water quality standards. However, the traces of lead (Pb), mercury (Hg), and arsenic (As) were higher than the permissible limits. The geopolymer-stabilized specimens achieved higher metallic ion encapsulation than cement and lime-stabilized specimens
Investigating the Anticancer Potential of Shikonin by Targeting PLK1 and Enhancing Therapeutic Efficacy Through Micellar Encapsulation in Oral Squamous Cell Carcinoma
No full textNatural bioactive alkaloid phytocompound shikonin is obtained from the Lithospermum erythrorhizon plant’s root and exhibits excellent pharmacological properties including anticancer activity. This study explores the mechanistic role of shikonin (Shk) in the proliferation and migration of oral squamous cell carcinoma (OSCC) cells. Shikonin suppresses the viability of SCC9 and H357 OSCC cells in a time and concentration-dependent manner. It promotes the generation of intracellular reactive oxygen species which then leads to the depletion of mitochondrial membrane potential (MMP). Further, this causes DNA damage and cell cycle arrest in the G2/M and S-G2/M phases in SCC9 and H357 cell lines respectively. Shk also induces apoptosis in OSCC cells via enhancing the expression of Bax and Caspase 3. It also suppresses colony formation and tumorigenicity in a dose-dependent manner. The molecular mechanism behind the anticancer activity of shikonin was analyzed using bioinformatics studies. It was found that out of all upregulated genes in oral cancer, polo-like kinase 1/PLK1 is the most significant one which is the key target of shikonin. The molecular docking and molecular dynamic simulation results showed that shikonin makes stable binding with PLK1 and inhibits its mode of action. It has been shown that after Shk treatment the mRNA expression level of PLK1 was decreased compared to the control. Knockdown of PLK1 reduces the proliferation and viability of OSCC cells. It also increases the apoptosis rate and DNA damage after siPLK1, similar to Shk treatment. Instead of having these excellent anticancer activities the clinical use of shikonin is still limited because of its poor bioavailability, solubility, and stability. To overcome this problem, polymeric micelles are used as a drug delivery vehicle. These micelles are smaller in size which helps micelles for easy penetration in cancer cells with increased permeability and retention effect. Here mPEG-SA micelles are used for shikonin encapsulation. The formation of blank and Shk-loaded micelles is characterized by 1HNMR, FTIR, CMC, drug-loading, and encapsulation efficiency, DLS, DSC, TEM, and drug release time. The shikonin-loaded micelles show better and prolonged toxicity compared to only shikonin treatment leading to cell death of OSCC cells. Hence it can be concluded that shikonin-loaded mPEG-SA micelles can be used as a therapeutic agent for effective delivery of shikonin in OSCC cells which can give prolonged and better anticancer effects
Red/Orange-Red Emitting Phosphors for Solid State Lightings: Structure-Compositions-Property-Correlations
No full textHighly 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
Multistep Improvement of Klebsiella sp. SWET4 Strain to Obtain Higher Ethanol Yield from Cellulosic Fruit Waste: Single Step for Waste to Energy Conversion
No full textThe pretreatment process involved in 2nd generation bioethanol production infers significant cost along with environmentally hazardous byproducts. Hence, its substitution with direct fermentation would significantly advance the process. Since raw substrate would be used during fermentation, its growth inhibitor content would be an important substrate selection criterion. This study revealed that the growth of Klebsiella sp. SWET4 was significantly reduced by phytate, phenolic acid, cyanide, and tannin at 3.09%, 0.22%, 0.38%, and 0.04% per μg/mL, respectively. Since banana peel contained the least amount of these growth inhibitors, it was predicted to be the best substrate for SWET4. Moreover, the potential of the banana peel as a probable substrate for ethanol production was evaluated with the help of logical prediction. The Whole Genome Sequencing of SWET4 (5665821 bases) revealed the presence of 5 major cellulose metabolizing (bcsZ, bglC, bglA, celA, chbA), besides 4 key xylan degrading (xynB, xynT, xylA, xylB) and 4 principal ethanol fermentation (nifJ, adhE, acs, adh1) genes. Expression study with qPCR confirmed the functionality of these genes. The lignolytic potential of SWET4 was evident in the kinetic study and the presence of yfeX/efeB, katG, katE, etc. genes was confirmed. SWET4adh1+adhE recombinant strain exhibited a remarkable 7.76-fold increase in ethanol productivity from the banana peel in facultative anaerobic conditions. qPCR analysis confirmed 106.15- and 22.78-fold higher expression of adh1 and adhE genes, respectively. Optimization using Artificial Neural Network modeling and Genetic Algorithm was found better than Response Surface Methodology (RSM) for predicting bioethanol production by SWET4adh1+adhE. After optimization, the enhanced biomass productivity of 2.33 g/L was achieved along with ethanol production of 24.47 g/L as confirmed by HPLC. The process demonstrated an ethanol yield of 0.44 g/g from carbohydrates surpassing many 2nd generation bioethanol processes. Further, a minimum selling price of $2/kg of distillate was found to make the process economically feasible which is significantly low. The breakeven point of the process was found to be 30% of its total capacity. The techno-economic analysis highlighted the feasibility, particularly emphasizing the economic advantages of eliminating pretreatment steps, highlighting the process’s innovation and viability in the field of 2nd generation bioethanol production
Design of High Power Interleaved Boost Converter with Enhanced Efficiency and Equal Current Distribution using Novel Control Algorithms
No full textIn 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
Role of Entrepreneurial Attitude in Fostering Entrepreneurial Intentions: An Empirical Study on Indian Institutes of Higher Learning
No full textOver the past few decades, technology, innovation, and entrepreneurship have emerged as significant driving forces behind economic and social advancement globally, attracting considerable attention from scholars, economists, educators, and policymakers. The contributions of new ventures in addressing economic crises, unemployment, and a lack of innovation are significant for national and regional development. This context has spurred growing scholarly interest in exploring the concept of “Entrepreneurial Intentions (EI)”. This study examines the factors influencing entrepreneurial attitudes and intentions among engineering students in Indian institutes of higher learning (IHLs). The research addresses a gap in the literature, which primarily focuses on developed countries, by exploring key predictors in the context of a developing country. As one of the fastest- growing major economies, India presents unique opportunities and challenges for entrepreneurship. Despite government initiatives like the “Atma Nirbhar Bharat Abhiyan” and various support schemes, the entrepreneurial landscape in India remains underdeveloped, particularly within higher education institutions. A structured questionnaire was distributed to final-year students from ten IHLs (4 IITs, 4 NITs, and 2 IIITs) using convenience sampling, yielding 529 valid responses. The collected data was analysed using software like SPSS (22.0) and AMOS (22.0). The results indicate that personality traits, contextual factors, and institutional support significantly influence entrepreneurial attitudes and intentions. The study underscores the central role of entrepreneurial attitudes as drivers of decision-making, shaped by personality traits and contextual support. Additionally, it highlights the importance of support institutions like Technology Business Incubators (TBIs) in enhancing students’ entrepreneurial intentions. The study contributes to developing effective strategies and interventions to foster an entrepreneurial mindset among engineering students, providing a framework for IHLs, practitioners, and policymakers. Ultimately, it proposes a holistic approach to nurturing a sustainable entrepreneurial ecosystem in Indian IHLs, promoting innovation, economic growth, and societal advancement
Mechanistic Insights on Phagosome-Lysosome Fusion by 4 (Benzyloxy)Phenol and its Effect on Intracellular Mycobacteria in Human Macrophages
No full textDrug-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