Assessment of Air and Water Quality in Opencast Mines

Mining Industry is one of the most important and revenue-generating industries of our country. It’s pivotal for the industry to thrive and grow to ensure that the manufacturing sector also develops at the required pace. But the detrimental effects of mining are far more dangerous than we can perceive and must be kept under check to reduce the polluting consequences on environment. Mining of any ore leads to befoulment of water bodies and also air contamination. The sources of air pollution in open cast mines are drilling and blasting of ore bodies, loading and haulage of blasted ore, handling of material and maintenance. The standards for air pollution have been set by National Ambient Air Quality Standards(NAAQS) and it’s based on criteria like PM2.5, PM10, SPM etc. PM2.5 and PM10 are the standards acceptable for respirable dust and pollutants. The water that runs off the mines can have detrimental effect on the water bodies that are in and around the mining areas. The seepage from ore bodies, mining waste rocks and treatment of effluents pose a great threat to the water bodies and the aquatic life associated with them. This project will assess the various parameters of water that decide the pollution level of the water body and will also focus on the dependency of ore type on the pollution level of the water bodies

Study the removal of fluoride from water by using chitin

Polymer is a large molecule (molecular weight ~10 000 or greater) composed of many smaller molecules (monomer) covalently bonded together. While the term polymer in popular usage suggests "plastic", polymers comprise a large class of natural and synthetic materials with a variety of properties purposes.Single polymer molecules typically have molecular weights between 10,000 and 1,000,000 g/mol--that can be more than 2000 repeating units depending on the polymer structure! The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights. The softening point (glass transition temperature) and the melting point of a polymer will determine which applications it will be suitable for. These temperatures usually determine the upper limit for which a polymer can be used. For example, many industrially polymers have glass transition temperatures near the boiling point of water (1000C, 212F), and they are most useful for room temperature applications. Some specially engineered polymers can withstand temperatures as high as 3000 C (572 F). Higher molecular weights. Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures (semi-crystalline). The polymer chains can be free to slide past one another (thermoplastic) or they can be connected to each other with cross links (thermosets or elastomer). Thermoplastics can be reformed and recycled, while thermosets and elastomers are not rework able. The chemical structure of the chains also has a tremendous effect on the properties. Depending on the structure the polymer may be hydrophilic or hydrophobic (likes or hates water), stiff or flexible, crystalline or amorphous, reactive or uncreative

Chemistry of Oxomolybdenum Complexes with ON- and ONO- Donor Ligands

Chapter 1: In this chapter the scope of the present investigation is delineated briefly along with the aim of the work. Chapter 2: Reaction of benzoylhydrazone of 2-hydroxybenzaldehyde (H2L) with [MoO2(acac)2] proceeds smoothly in refluxing ethanol to afford an orange complex [MoO2L(C2H5OH)] (1). The substrate binding capacity of complex (1) has been demonstrated by the formation and isolation of two mononuclear [MoO2L(Q)] {where Q = imidazole (2a) and 1-methylimidazole (2b)} and one dinuclear [(MoO2L)2(Q)] {Q = 4,4'-bipyridine (3)} mixed-ligand oxomolybdenum complexes. All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and NMR) measurements. Molecular structures of all the oxomolybdenum(VI) complexes (1, 2a, 2b and 3) have been determined by X-ray crystallography. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The minimum inhibitory concentration of these complexes and antibacterial activity indicates the compound 2a and 2b as the potential lead molecule for drug designing. Chapter 3: Reaction of the salicyloylhydrazone of 2-hydroxy-1-naphthaldehyde (H2L1), anthranylhydrazone of 2-hydroxy-1-naphthaldehyde (H2L2), benzoylhydrazone of 2-hydroxy-1-acetonaphthone (H2L3) and anthranylhydrazone of 2-hydroxy-1-acetonaphthone (H2L4; general abbreviation H2L) with [MoO2(acac)2] afforded a series of 5- and 6- coordinate Mo(VI) complexes of the type [MoO2L1–2(ROH)] [where R = C2H5 (1) and CH3 (2)], and [MoO2L3–4] (3 and 4). The substrate binding capacity of 1 has been demonstrated by the formation of one mononuclear mixed-ligand dioxomolybdenum complex [MoO2L1(Q)] {where Q = γ-picoline (1a)}. Molecular structure of all the complexes (1, 1a, 2, 3 and 4) is determined by X-ray crystallography, demonstrating the dibasic tridentate behavior of ligands. All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and vi NMR) measurements. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis, Proteus vulgaris and Klebsiella pneumoniae. The minimum inhibitory concentration of these complexes and antibacterial activity indicates 1 and 1a as the potential lead molecule for drug designing. Catalytic potential of these complexes was tested for the oxidation of benzoin using 30% aqueous H2O2 as an oxidant in methanol. At least four reaction products benzoic acid, benzaldehyde-dimethylacetal, methylbenzoate and benzil were obtained with the 95-99% conversion under optimized reaction conditions. Oxidative bromination of salicylaldehyde, a functional mimic of haloperoxidases, in aqueous H2O2/KBr in the presence of HClO4 at room temperature has also been carried out successfully. Chapter 4: Report of synthesis and characterization of two novel dimeric [(MoVIO2)2L] (1) and tetrameric [{(C2H5OH)LO3Mo2VI}2(-O)2]·C2H5OH (2) dioxomolybdenum(VI) complexes with N,N'-disalicyloylhydrazine (H2L), which is formed by the self combination of salicyloyl hydrazide. Both the complex was characterized by various spectroscopic techniques (IR, UV–Vis and NMR) and also by electrochemical study. The molecular structures of both the complexes have been confirmed by X-ray crystallography. All these studies indicate that the N,N'-disalicyloylhydrazine (H2L) has the normal tendency to form both dimeric and tetrameric complexes coordinated through the dianionic tridentate manner. Chapter 5: Two novel dioxomolybbdenum(VI) complexes containing the MoO22+ motif are reported where unexpected coordination due to ligand rearrangement through metal mediated interligand C–C bond formation is observed. The ligand transformations are probably initiated by molybdenum assisted C–C bond formation in the reaction medium. The ligands (H2L1–2) are tetradentate C–C coupled O2N2– donor systems formed in situ during the synthesis of the complexes by the reaction of bis(acetylacetonato)dioxomolybdenum(VI) with Schiff base ligands of 2-aminophenol with 2-pyridine carboxaldehyde (HL1) and 2-quinolinecarboxaldehyde (HL2). The reported dioxomolybdenum(VI) complexes [MoO2L1] (1) and [MoO2L2] (2) coordinated with the O2N2– donor rearranged ligand are expected to have better stability of the molybdenum in +6 oxidation state than the corresponding ON2–donor ligand precursor. Both the complexes are fully characterized by several physicochemical techniques and the novel structural features through single crystal X-ray crystallography. vii Chapter 6: In this chapter we present a detailed account of the synthesis, structure, spectroscopic, electrochemical properties and study of biological activity of some oxomolybdenum(VI) complexes with special reference to their H–bonded molecular and supramolecular structures. Reaction of bis(acetylacetonato)dioxomolybdenum(VI) with three different hydrazides (isonicotinoyl hydrazide, anthraniloyl hydrazide and 4-nitrobenzoyl hydrazide) afforded two di-oxomolybdenum(VI) complexes {[MoO2L1(CH3OH)] (1) and [MoO2L3] (3)} and one mono-oxomolybdenum(VI) complex {[MoOL2(O–N)] (2)} (where L = Intermediate in situ ligand formed by the reaction between acetyl acetone and the corresponding acid hydrazide, and O–N = 4-nitrobenzoylhydrazide). All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and NMR) measurements. Molecular structures of all the complexes (1, 2 and 3) have been determined by X-ray crystallography. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The Minimum inhibitory concentration of these complexes and antibacterial activity indicates 1 as the potential lead molecule for drug designing

Investigation of DNA interaction and antiproliferative activity of mixed ligand dioxidomolybdenum(VI) complexes incorporating ONO donor aroylhydrazone ligands

Four new mixed ligand dioxidomolybdenum(VI) [MoVIO2L1-3(Q)] (1–3), [MoVIO2L4(Q)]2 (H2O) (4) [where Q = MeOH for 1 and imidazole for 2–4] complexes have been synthesized using four different ONO donor aroylhydrazone ligands (H2L1–4). All the derived ligands and complexes have been characterised by different physicochemical techniques, that is, elemental analysis, spectroscopic methods (UV–Vis, NMR and IR), and cyclic voltammetry. The molecular geometries of 1–4 were established by X-ray crystallography which reveals - - the Schiff base ligands coordinate - the distorted octahedral metal centres in a di-negative tridentate fashion. The complexes have shown moderate binding affinity (103 to 104 M−1) towards CT-DNA. Further, in vitro cytotoxicity activity of all the complexes were determined against HT-29 (colon cancer) and HeLa (cervical cancer) cell lines. Complex 4, due to the presence of a heterocyclic 2-hydroxy-1-naphthyl moiety in the ligand backbone, was found to be more biologically active in comparison to the others in the series

Monocrystalline Si/β\beta-Ga2_2O3_3 p-n heterojunction diodes fabricated via grafting

The $\beta$-Ga$_2$O$_3$ has exceptional electronic properties with vast potential in power and RF electronics. Despite the excellent demonstrations of high-performance unipolar devices, the lack of p-type doping in $\beta$-Ga$_2$O$_3$ has hindered the development of Ga$_2$O$_3$-based bipolar devices. The approach of p-n diodes formed by polycrystalline p-type oxides with n-type $\beta$-Ga$_2$O$_3$ can face severe challenges in further advancing the $\beta$-Ga$_2$O$_3$ bipolar devices due to their unfavorable band alignment and the poor p-type oxide crystal quality. In this work, we applied the semiconductor grafting approach to fabricate monocrystalline Si/$\beta$-Ga$_2$O$_3$ p-n diodes for the first time. With enhanced concentration of oxygen atoms at the interface of Si/$\beta$-Ga$_2$O$_3$, double side surface passivation was achieved for both Si and $\beta$-Ga$_2$O$_3$ with an interface Dit value of 1-3 x 1012 /cm2 eV. A Si/$\beta$-Ga$_2$O$_3$ p-n diode array with high fabrication yield was demonstrated along with a diode rectification of 1.3 x 107 at +/- 2 V, a diode ideality factor of 1.13 and avalanche reverse breakdown characteristics. The diodes C-V shows frequency dispersion-free characteristics from 10 kHz to 2 MHz. Our work has set the foundation toward future development of $\beta$-Ga$_2$O$_3$-based transistors.Comment: 32 pages, 10 figures. The preliminary data were presented as a poster in the 5th US Gallium Oxide Workshop, Washington, DC. August 07-10, 202

A study of DNA/BSA interaction and catalytic potential of oxidovanadium(V) complexes with ONO donor ligands

The study of DNA/BSA interaction and the catalytic potential of four mononuclear oxidoalkoxido vanadium(V) [VVO(L¹⁻⁴)OEt] (1–4) and one dinuclear oxidoalkoxido mixed-ligand vanadium(V) [{VO(L²)OEt} ₂ (Q)]{Q = 4,4′-bipyridine}(5) complexes, with tridentate binegative aroylazine ligands are reported [where H₂L¹ = anthranylhydrazone of 2- hydroxy-1- napthaldehyde, H₂L² = salicylhydrazone of 2-hydroxy-1- napthaldehyde, H₂L³ = benzoylhydrazone of 2-hydroxy-1- acetonaphthone, H₂L⁴ = anthranylhydrazone of 2-hydroxy-1- acetonaphthone]. All the complexes are characterized by elemental analysis as well as various spectroscopic techniques. Single crystal X-ray diffraction crystallography of 2 reveals that the metal centre is in distorted square pyramidal geometry with O₄N coordination spheres, whereas 5 exhibits a distorted octahedral geometry around the metal center. In addition, all the complexes (1–5) show moderate DNA binding propensity which is investigated using UV-vis absorption titration, circular dichroism, thermal denaturation and fluorescence spectral studies. The experimental results show that the complexes effectively interact with CT-DNA through both minor and major groove binding modes, with binding constants ranging from 10⁴ −10⁵ M⁻¹. Among 1–5, complexes 3 and 4 show higher binding affinity towards CT-DNA than others and at the same time also exhibit negative ΔTm values of about ∼1.5 and 1.0 °C which resembles the properties shown by cisplatin. All complexes show moderate photo-induced cleavage of pUC19 supercoiled plasmid DNA with complex 3 showing the highest photo induced DNA cleavage activity of ∼48%. In coherence with the DNA interaction studies, 3 and 4 also exhibit good binding affinity towards BSA in the range of 10¹⁰ −10¹¹ M⁻¹, which is also supported by their ability to quench the tryptophan fluorescence emission spectra of BSA. All the complexes show remarkable photo-induced BSA cleavage activity (>90%) at a complex concentration of 50 μM. The catalytic potential of 1–5 is also tested for the oxidative bromination of styrene, salicylaldehyde and oxidation of methyl phenyl sulphide. All the reactions show a high percentage of conversion (>90%) with a high turnover frequency (TOF). Particularly, in the oxidative bromination of styrene the percentage of conversion and TOF vary from 96–98% and 8000–19 600 (h⁻¹) respectively, which signifies the potential of these oxidovanadium(V) complexes to stimulate research for the synthesis of a better catalyst

Monomeric and dimeric oxidomolybdenum(V and VI) complexes, cytotoxicity, and DNA interaction studies: molybdenum assisted C═N bond cleavage of salophen ligands

Four novel dimeric bis-μ-imido bridged metal–metal bonded oxidomolybdenum(V) complexes [MoV2O2L′21–4] (1–4) (where L′1–4 are rearranged ligands formed in situ from H2L1–4) and a new mononuclear dioxidomolybdenum(VI) complex [MoVIO2L5] (5) synthesized from salen type N2O2 ligands are reported. This rare series of imido- bridged complexes (1–4) have been furnished from rearranged H3L′1–4 ligands, containing an aromatic diimine (o-phenylenediamine) “linker”, where Mo assisted hydrolysis followed by −C═N bond cleavage of one of the arms of the ligand H2L1–4 took place. A monomeric molybdenum(V) intermediate species [MoVO(HL′1–4)(OEt)] (Id1–4) was generated in situ. The concomitant deprotonation and dimerization of two molybdenum(V) intermediate species (Id1–4) ultimately resulted in the formation of a bis-μ-imido bridge between the two molybdenum centers of [MoV2O2L′21–4] (1–4). The mechanism of formation of 1–4 has been discussed, and one of the rare intermediate monomeric molybdenum(V) species Id4 has been isolated in the solid state and characterized. The monomeric dioxidomolybdenum(VI) complex [MoVIO2L5] (5) was prepared from the ligand H2L5 where the aromatic “linker” was replaced by an aliphatic diimine (1,2-diaminopropane). All the ligands and complexes have been characterized by elemental analysis, IR, UV–vis spectroscopy, NMR, ESI- MS, and cyclic voltammetry, and the structural features of 1, 2, 4, and 5 have been solved by X-ray crystallography. The DNA binding and cleavage activity of 1–5 have been explored. The complexes interact with CT-DNA by the groove binding mode, and the binding constants range between 103 and 104 M–1. Fairly good photoinduced cleavage of pUC19 supercoiled plasmid DNA was exhibited by all the complexes, with 4 showing the most promising photoinduced DNA cleavage activity of ∼93%. Moreover, in vitro cytotoxic activity of all the complexes was evaluated by MTT assay, which reveals that the complexes induce cell death in MCF-7 (human breast adenocarcinoma) and HCT-15 (colon cancer) cell lines

Design and application of compliant III-nitride substrates using Porous GaN

With the invention of efficient Gallium Nitride (GaN) based blue light emitting diodes (LEDs), the lighting sector has been revolutionized. The blue light is converted into white using a yellow phosphor coating. These white light sources are currently being heavily utilized in the backlight units of liquid crystal displays (LCDs) in residential and commercial settings. This white light goes through various stages such as multiple polarizers, liquid crystals, and color filters, leading to a reduced light output. Recently, organic LEDs have emerged as a premium display technology due to their self-emissive nature leading to extremely high contrast ratio and improved overall efficiency. However, due to their organic nature, they are susceptible to degradation over time and require sophisticated encapsulation due to their sensitivity to moisture and oxygen. Hence, the use of self-emissive inorganic LEDs is highly desired which will have extremely high contrast ratio and at the same time have very high lifetime, brightness, and efficiency. For the three basic colors red, green and blue, different materials are preferred. The Indium Gallium Nitride (InGaN) alloy system spans a bandgap of 0.7 – 3.4 eV covering the full visible spectrum. However, only blue and green emitting InGaN LEDs are preferred by display manufacturers, as the efficiency of InGaN LEDs emitting beyond green in the visible spectrum reduces drastically. The higher indium content necessary to emit light in the longer wavelength of emission is accompanied by a lot of defects. As InN and GaN have a 10% lattice mismatch, the increased indium content increases the strain in the epitaxial structure causing defect formation. Hence, Aluminum Indium Gallium phosphide (AlInGaP) based red emitters are preferred as they offer very high efficiency in the red emission range. To facilitate cost effective commercialization and provide an immersive user experience in near eye displays, the inorganic LED sizes must be scaled to dimensions < 10 µm. Due to unfavorable material properties, scaling of the phosphide based red emitters is met with a lot of challenges. Hence, InGaN based scaled red emitters are needed. Our approach was to target the strain in the epitaxial structure by utilizing a flexible underlayer that can be visualized as a strain reducing layer. The flexible material of our choice was porous GaN, which could be obtained using a doping selective electrochemical etching process. This etching process could convert the GaN:Si films into porous GaN films. Using this flexible underlayer, elastic strain relaxation was demonstrated for InGaN films in the micrometer scale regime, leading to very high-quality epitaxial layer growth. Prior demonstrations of elastic strain relaxation were in the nanometer scale regime, posing challenges in device fabrication. With this substrate technology, the first red micro-LED sized < 10 µm was demonstrated with measurable efficiency. Beyond InGaN, the growth of relaxed AlGaN films was also pursued. 1.3 µm thick crack-free relaxed Al0.2Ga0.8N was grown using these substrates. With continued development large area strain relaxed AlGaN with arbitrary lattice constant can be demonstrated, that can be utilized not only for AlGaN based UV-LEDs but also for AlGaN electronics applications