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Solāpur, India

Ghodake U.R.,Shri Shivaji Mahavidyalaya | Chaudhari N.D.,Pratishthan Mahavidyalaya | Kambale R.C.,University of Pune | Patil J.Y.,University of Solapur | Suryavanshi S.S.,University of Solapur
Journal of Magnetism and Magnetic Materials

In this work, Mn substituted Mg-Zn spinel ferrites having general formula Zno.4Mg0.6-xMnxFe2O4 (0≤x≤0.30) have been synthesized by oxalate precursor chemical method and investigated their structural, magnetic and electric properties. X-ray diffraction (XRD) is used to study the crystal structure of synthesized materials. XRD study reveals the formation of polycrystalline cubic spinel lattice structure without any impurity phase having crystallite size in the range from 39.97 nm to 45.62 nm. Scanning electron micrographs revealed, increase in grain size (D) with increase in Mn2+ content up to x=0.10; then it decreases for x>0.10. Energy dispersive x-ray analysis (EDAX) confirms the presence of Mg2+, Mn2+, Fe3+, Zn2+ and O2- ions as per the stoichiometry. The magnetic moment (nB), with Mn2+ substitution is found to increase initially up to x=0.10 and then it deceases with further Mn2+ substitution. The observed variation in the magnetic moment (nB) is explained by considering the variation of saturation magnetization, anisotropy constant, density values and exchange interaction. The d.c. electrical resistivity decreased with increase in temperature in accordance with semiconducting behavior. Furthermore, the conductivity was found to obey the Arrhenius relation with a change in slope at critical temperature (i.e. the Curie temperature). The increase in d.c. resistivity is attributed to the hindering of Verwey mechanism between Fe2+⇔Fe3+ ions and Mn2+⇔Mn3+. The dielectric constant (ε′) measurement revealed the dielectric dispersion behavior in accordance with the Maxwell-Wagner model and Koops phenomenological theory, which is responsible for conduction and polarization. The dielectric characteristics (ε′, ε″ and tan δ) exhibit dispersion due to Maxwell-Wagner type interfacial polarization. The values of dielectric constant (ε′) and a.c. resistivity (ρac) exhibit highest magnitude at x=0.10 and decreases further with Mn2+ substitution. © 2016 Elsevier B.V. All rights reserved. Source

Kulal S.R.,Metal Oxide Research Laboratory | Khetre S.S.,Metal Oxide Research Laboratory | Jagdale P.N.,Metal Oxide Research Laboratory | Gurame V.M.,Shri Shivaji Mahavidyalaya | And 4 more authors.
Materials Letters

Dysprosium doped Co-Zn ferrites were synthesized by sol-gel auto combustion method. These synthesized compounds were characterized by using XRD, SEM, FTIR, EDS, TGA-DTA and TEM. TGA weight loss in the region of 100-200°C and this loss is due to autocatalytic oxidation reduction reactions of nitrates with glycine. The composition Co 0.5Zn 0.5Fe 2-xDy xO 4 (x=0.075) shows fibrous reticulated mesh like morphology. The average grain size increases with increasing the Dy content in the Co-Zn ferrite. The XRD study of Dy doped Co-Zn ferrite shows in Cubic spinel phase. Particle size obtained from TEM analysis was found to be 30-40 nm. The FTIR spectra showed the characteristic of two strong absorption bands at 560 cm -1 corresponds to intrinsic stretching vibrations of the metal at the tetrahedral site and lowest band is observed at 455 cm -1 corresponds to octahedral site. © 2012 Elsevier B.V. All rights reserved. Source

Kamble A.P.,Shriman Bhausaheb Zadhabuke Mahavidyalaya | Thorat P.,Shri Shivaji Mahavidyalaya | Kulkarni S.W.,Shriman Bhausaheb Zadhabuke Mahavidyalaya
OnLine Journal of Biological Sciences

Problem statement: Soil Pollution is major problem because different types of pesticides are used to control plant pest. The residual component of pesticide diffuses into the soil. It is necessary to check whether actinomycetes degrade these components and control the soil pollution. Approach: In Ayurved system of medicine the rhizome portion of Curcuma longa L. was used as an anti-inflammatory and antiseptic. Antimicrobial substances released from these plants diffuse into the surrounding soil area of the plant. Actinomycete which grow in these area were resistant to these substances. Hence considerable attention had been given in studying the effect of inhibitory substances on actinomycetes especially Microbiospora isolated from soil under cultivation of Curcuma longa L. Results: The present study deals with effect of inhibitory substances like dettol, phenol, sodium azide, lysol and crystal violet. The results were recorded on the basis of presence or absence of growth. All five isolates of Microbiospora were found sensitive against dettol. One strain of Microbiospora was found resistant to phenol. Conclusion/Recommendations: From the study performed we conclude that Microbiospora which is resistant to phenol and other inhibitory substances can be used to degrade the residual components of pesticide which are released into the soil. It may have better option to prevent soil pollution. © 2012 Science Publications. Source

Sowani H.M.,Walchand Center for Biotechnology | Thorat P.,Shri Shivaji Mahavidyalaya
OnLine Journal of Biological Sciences

Problem statement: In the present study, Staphylococcus aureus a causative agent of food poisoning is selected as a test organism to study the antimicrobial effect of bacteriocin. S. aureus produces number of exotoxins and enterotoxins which enters the body via contaminated food causing illness. Approach: In this case the use of antibiotics is one of the ways of treatment, but in addition to this if we advise such patients to consume the carrot kanji then it will cause better effect because carrot kanji is the naturally fermented food beverage consisting of microflora mainly the Lactobacilli. Results: The Lactobacilli have ability to produce antimicrobial compounds called bacteriocin. Isolation of bacteriocin was carried out from the naturally fermented carrot kanji. The bacteriocin produced by Lactobacilli was dialysed and used for the further studies. The well diffusion method is used to study the antimicrobial activity, effect of temperature, pH, enzymes on bacteriocin. From the diameter of zone of inhibition the activity of bacteriocin was determined. The sensitivity of bacteriocin at different pH range showed that at neutral pH the diameter of inhibition zone was greater than that at alkaline as well as acidic pH. Upto 100°C the bacteriocin activity was 80% but as temperature range increased upto 121°C it reduced sharply to 28%. Conclusion/Recommendations: In addition to this the effect of alpha amylase, trypsin, catalase enzyme on bacteriocin activity was also studied which shows positive results with alpha amylase, reduced activity with trypsin and catalase remained unaffected. © 2012 Science Publications. Source

Bhosale A.K.,Raje Ramrao College | Kulal S.R.,Raje Ramrao College | Gurame V.M.,Shri Shivaji Mahavidyalaya | Patil P.S.,Shivaji University
Bulletin of Materials Science

Optically passive thin films of CeO2-TiO2 mixed oxides with molar ratio of Ce/Ti of 0.05 were deposited by the spray pyrolysis technique (SPT) on a glass and fluorine-doped tin oxide (FTO)-coated glass substrates. Precursor solution containing cerium nitrate hexahydrate (Ce(NO3)2·6H2O) and titanium tetraiso-propoxide (Ti(OiPr)4) having different volumetric proportions (0-5 vol% of Ti) in methanol were used. These films were characterized for structural, morphological, molecular, optical, electrochromic and colourimetric analysis. CeO2-TiO2 films deposited at 400° C were found to be polycrystalline with cubic fluorite crystal structure. Transformation from polycrystalline to amorphous phase was observed with increasing TiO2 content. The band centred at 539 cm-1 is assigned to Ce-O stretching vibration and the two medium intensity bands assigned to (Ti-O) and (Ti-O-Ti) stretching modes at 798 and 451 cm-1, which confirms the mixed CeO2 and TiO2 phases. The band gap energy decreases (Eg) from 3.45 eV for pristine CeO2 to 2.98-3.09 eV for CeO2-TiO2 films. The ion storage capacity (ISC) of CeO2-TiO2 thin film with 3 vol% Ti (Ce-Ti3 sample) was found to be 26 mC cm-2 and electrochemical stability up to 30,000 cycles in 0.5 M LiClO4-PC electrolyte. The optically passive behaviour of CeO2-TiO2 thin film is confirmed by its negligible transmission modulation (Δ T ∼ 2.5%) upon Li+ ion insertion/extraction, irrespective of the extent of Li+ ion intercalation. The optical modulation of sputter deposited electrochromic WO3 thin film was found to be enhanced from 56 to 61% with rapid increase in colouration efficiency (CE) from 42 to 231 cm2 C-1 when CeO2-TiO2 is coupled as a counter electrode with WO3 in an electrochromic device (ECD). On reduction of WO3 thin film with CeO2-TiO2 as counter electrode, the CIELAB 1931 2° colour space coordinates show the transition from colourless to the deep blue state (L∗ = 88.07, a∗ = -2.37, b∗ = 24.59 and L∗ = 40.32, a∗ = -1.16, b∗ = -5.65) with steady decrease in relative lightness. Yxy and L∗ a∗ b∗ coordinates signify CeO2-TiO2 films and it also exhibits the application as counter electrode in electrochromic smart windows in which they are able to retain their transparency under charge insertion/extraction. © Indian Academy of Sciences. Source

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