Evaluation of Ethylene Propylene Diene Terpolymer based insulation against Nitrile rubber based insulation for large Composite Rocket Motor Casing

Even though literature available on EPDM is abundant, the data on physical, mechanical, thermal, interface properties and ablative performance as specifically required for the design and acceptance of internal insulation of large Composite Rocket Motor Casing is scant in the plethora of literature available in the subject of EPDM insulation. This gave the impetus to take up this experimental work wherein most promising formulation of EPDM with Kevlar and silica as reinforcing fillers and with only silica as reinforcing filler were thoroughly characterized for the insulation requirements of large Composite Rocket Motor Casing and compared with the performance of proven Nitrile rubber based insulation. The significant findings which are unique, are discussed in this paper.     

Phototransformations of some 3‐cyclohexenyloxychromenones: Synthesis of Spirocyclic compounds

The phototransformation of the 3‐cyclohexenyloxychromenones by irradiation with a pyrex‐filtered light from a 125 W Hg vapor lamp under an inert atmosphere into the spirocyclic fused xanthenones was described. The efficacy of the protocol depended upon the position (o‐, m‐, or p‐) of the cyclohexenyloxy group appended to the 2‐aryl moiety on the chromenone nucleus, which was further invoked by steric, electronic, and proximity considerations. The structure(s) of the substrates and photoproducts were established using the spectroscopic (IR and NMR) data.     

Design and development of bioactive α-hydroxy carboxylate group modified MnFe2O4 nanoparticle: Comparative fluorescence study,magnetism and DNA nuclease activity

Three new α-hydroxy carboxylate group functionalized MnFe₂O₄ nanoparticles (NPs) have been developed to explore the microscopic origin of ligand modified fluorescence and magnetic properties of nearly monodispersed MnFe₂O₄ NPs. The surface functionalization has been carried out with three small organic ligands (tartrate, malate, and citrate) having different number of α-hydroxy carboxylate functional group along with steric effect. Detailed study unveils that α-hydroxy carboxylate moiety of the ligands plays key role to generate intrinsic fluorescence in functionalized MnFe₂O₄ NPs through the activation of ligand to metal charge transfer transitions, associated with ligand–Mn²⁺/Fe³⁺ interactions along with d–d transition corresponding to d–orbital energy level splitting of Fe³⁺ ions on NP surface. Further, MnFe₂O₄ NPs show a maximum 140.88% increase in coercivity and 97.95% decrease in magnetization compared to its bare one upon functionalization. The ligands that induce smallest crystal field splitting of d–orbital energy level of transition metal ions are found to result in strongest ferrimagnetic activation of the NPs. Finally, our developed tartrate functionalized MnFe₂O₄ (T-MnFe₂O₄) NPs have been utilized for studying DNA binding interaction and nuclease activity for stimulating their beneficial activities toward diverse biomedical applications. The spectroscopic measurements indicate that T-MnFe₂O₄ NPs bind calf thymus DNA by intercalative mode. The ability of T-MnFe₂O₄ NPs to induce DNA cleavage was studied by gel electrophoresis technique where the complex is found to promote the cleavage of pBR322 plasmid DNA from the super coiled form I to linear coiled form II and nicked coiled form III with good efficiency.     

Silk Mat as Bio-matrix for the Immobilization of Cholesterol Oxidase

Cholesterol oxidase (ChOx) was covalently immobilized onto the woven silk fiber (silk mat) produced by Antheraea assamensis. The immobilization was done using N-ethyl-N’-(3-dimethylaminopropyl) carbodimide and N-hydroxysuccinimide ligand chemistry. The attachment of ChOx to the silk mat was demonstrated by scanning electron microscopy and activity study. The kinetic studies of the immobilized ChOx were performed by using a biological oxygen monitor. The enzyme loading was found to be 0.046 U cm^?2 of silk mat and the enzyme loading efficiency of the silk mat was estimated to be 70%. Remarkably high storage and operational stability (t_1/2 of initial activities) corresponding to 13 months and 25 numbers of assay (for a period of 6 h), respectively, of the fabricated ChOx electrode were demonstrated.     

Multinuclear copper complexes of pyridylmethylamide ligands

Copper complexes of a family of pyridylmethylamide ligands HL(Ph), HL(Me3) and HL(Ph3) were synthesized and characterized [HL(Ph) = 2-phenyl-N-(2-pyridylmethyl)acetamide; HL(Me3) = 2,2-dimethyl-N-(2-pyridylmethyl)propionamide; HL(Ph3) = 2,2,2-triphenyl-N-(2-pyridylmethyl)acetamide]. The reaction of copper(II) salts with the HL family and triethylamine in methanol yields copper(II) complexes [Cu4(L(Ph))4(OH)2](ClO4)2 (1), [Cu2(HL(Me3))2(OMe)2(MeOH)2](OTf)2 (2) and [Cu2(HL(Ph3))2(OMe)2(MeOH)2](OTf)2 (3). The complexes have different nuclearity owing to varying steric properties of the ligands used. Complex 1 self-assembles in the presence of excess base to form a tetranuclear complex. Complexes 2 and 3 are binuclear and are bridged by a pair of methoxide ligands. Steric encumbrance of the ligands in 2 and 3 prevent cluster formation.     

Synthesis of some new fluorine-containing 5-amino-1,3-disubstituted pyrazoles and 1H-pyrazolo[3,4-b]pyridines

Nine new fluorine containing 5-amino-1,3-disubstituted pyrazoles have been synthesized and characterized by spectral studies. Condensation reactions of these 5-amino-1,3-disubstituted pyrazoles with fluorinated 1,3-diketones in the presence of glacial acetic acid have been studied and the structures of the resulting 1H-pyrazolo[3,4-b]pyridines have been confirmed by ir, pmr and ¹⁹F nmr spectral studies.     

Studies on 4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone complexes of some bivalent metal ions

Summary Complexes [VO(Htaptsc)SO₄] and [M(Htaptsc)₂Cl₂] [M=Mn^II, Ni^II, Cd^II or Hg^II], Cu(Htaptsc)Cl₂ and [M(Htaptsc)Cl₂] [M=Co^II or Zn^II], and deprotonated compounds Co(taptsc)₂ and [M(taptsc)₂] [M=V^IVO, Mn^II, Ni^II, Cu^II or Zn^II] [Htaptsc=4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone] have been characterized by elemental analyses, electrical conductivity and magnetic susceptibility measurements and electronic, e.s.r. and i.r. spectroscopy. The bonding sites of Htaptsc and the bonding and stereochemistry of the complexes are discussed.     

Studies on 4-(2-thiazolyl)-1-(2,6-diacetylpyridine)thiosemicarbazone complexes of some bivalent metal ions

Summary Complexes of 4-(2-thiazolyl)-1-(2,6-diacetylpyridine)-thiosemicarbazone, H₂C₃NSCNH(S)NHNCMeC₅H₃N-C(O)Me (Htdaptsc) of the compositions [M(Htdaptsc)₂Cl₂] [M=Mn^II, Co^II, Ni^II or Zn^II] [M(Htdaptsc)Cl₂] [M=Zn^II, Cd^II or Hg^II] and [M(tdaptsc)₂] [M=Mn^II, Co^II, Ni^II, Cu^II, or Zn^II] have been prepared and characterized by elemental analyses, molar conductance, magnetic susceptibility, electronic, e.s.r. and i.r. studies, and their stereochemistries are discussed.     

Extractive separation of lower valent vanadium by complexation with picolinic acid

Summary Vanadium (III), obtained by sodium dithionite reduction of vanadium (V), forms a coloured complex with picolinic acid which is extracted into chloroform from slightly acidic medium. The method is free from interference by relatively high concentrations of analytical important elements such as iron, cobalt, nickel, zinc, copper, titanium, aluminium, chromium, molybdenum, tungsten and uranium. The proposed method of separation is simple and rapid and its applicability has been tested by the satisfactory recovery of vanadium from a variety of synthetic and natural samples.