Kuvempu University

About: Kuvempu University is a education organization based out in Shimoga, India. It is known for research contribution in the topics: Cyclic voltammetry & Carbon paste electrode. The organization has 1575 authors who have published 2210 publications receiving 39755 citations. The organization is also known as: KU.

Synthesis of visible light active Gd3+-substituted ZnFe2O4 nanoparticles for photocatalytic and antibacterial activities

Abstract: In the present analysis, we study the assembly of a low-cost and visible light active ZnFe2-xGdxO4 (x = 0 , 0.3, 0.5 and 0.7) nanoparticles (NPs) photocatalyst. The synthesized samples were characterized by several physicochemical techniques, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible absorption spectroscopy (UV-Vis), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The phase transition from cubic to orthorhombic was confirmed by XRD patterns. The increase in the concentration of Gd3+ substitution in ZnFe2O4 NPs enhances the redshift of absorption in the visible region of UV-Vis absorption spectra and reduces the band gap. In the photo-Fenton-type reaction, the gadolinium-substituted zinc ferrite (ZGF) NPs exhibit a significant catalytic activity for the degradation of methylene blue (99% in 90 minutes) under visible light (500W xenon lamp) with respect to bare samples (95% in 240 minutes) and they also show an excellent reusability nature. These materials were also screened for antibacterial activity against Gram-negative bacteria strains (Pseudomonas aeruginosa and Escherichia coli).

Structural, dielectric, ac conductivity and electromagnetic shielding properties of polyaniline/Ni 0.5 Zn 0.5 Fe 2 O 4 composites

Abstract: A conducting polymer, polyaniline (PANI)/Ni0.5Zn0.5Fe2O4 composites with high dielectric absorbing properties and electromagnetic shielding effectiveness at low frequencies were successfully synthesized through a simple in situ emulsion polymerization. PANI was doped with hydrochloric acid to improve its electrical properties and interactions with ferrite particles. PANI/Ni0.5Zn0.5Fe2O4 composites were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Frequency dependence of dielectric and ac conductivity (σac) studies have been undertaken on the PANI/Ni0.5Zn0.5Fe2O4 composites in the frequency range 50 Hz–5 MHz. The electrical conduction mechanism in the PANI/Ni0.5Zn0.5Fe2O4 is found to be in accordance with the electron hopping model. Further, frequency dependence of electromagnetic interference (EMI) shielding effectiveness (SE) is studied. The EMI shielding effectiveness is found to decrease with an increase in the frequency. The maximum value 55.14 dB of SE at 50 Hz was obtained at room temperature for PANI/Ni0.5Zn0.5Fe2O4 composites in the 50 Hz–5 MHz frequency range. PANI/Ni0.5Zn0.5Fe2O4 composites were demonstrated as a promising functional material for the absorbing of electromagnetic waves at low frequencies because of a large amount of dipole polarizations in the polymer backbone and at the interfaces of the Ni–Zn ferrite particles and PANI matrix.

Evaluation of arbuscular mycorrhiza and other biocontrol agents in managing Fusarium oxysporum f. sp. Cubense infection in banana cv. Neypoovan

Abstract: Panama wilt of banana caused by Fusarium oxysporum f. sp. cubense (race 1) is a serious disease devastating the important cultivar Neypoovan (syn Elakki Bale AB) in southern India. Chemical control methods are not very effective in controlling the disease. The objective of this study was to evaluate biocontrol agents (BCAs) under controlled and field conditions for their efficacy against the pathogen and to detect and quantify the reduction in FOC population. Arbuscular mycorrhizal (AM) fungi, Trichoderma harzianum and Pseudomonas fluorescens were inoculated at the time of planting in single, dual and tripartite combinations allowing colonization up to 0, 45 and 90 days. Plants were challenged thereafter with 50 g of FOC inoculum multiplied on sorghum grains containing 1.5×106 cfu g−1. Uninoculated plants and those inoculated with pathogen only were controls. Plant growth parameters were measured and structural modifications in the roots were studied. FOC populations in the roots were determined ...

Optimization and production of neomycin from different agro industrial wastes in solid state fermentation

Abstract: The cost of neomycin production may be significantly decreased by using inexpensive carbon substrates like agricultural residues. However, scarce information can be found in the literature about the utilization of cellulosic and lignocellulosic residues for obtaining neomycin. Usually agricultural residues producing various toxic compounds to the atmosphere; so, as an interesting alternative to the utilization of agricultural wastes (as apple pomace, cotton seed meal, soy bean powder and wheat bran) for simultaneous neomycin production. The highest neomycin production (2765 µg/g substrate) was achieved with apple pomace in solid-state fermentation. The optimization of physical parameters such as inoculum size, substrate particle size, incubation temperature, initial pH, initial moisture level, incubation period and chemical parameters such as additional carbon and nitrogen sources were studied for the production of neomycin in solid-state fermentation using Streptomyces fradiae NCIM 2418. The optimum values of the critical components determined for the maximum neomycin production were inoculum size 2×10 6 CFU/g initial dry substrate, substrate particle size 1.2 mm, incubation temperature 30 o C, initial pH 8, initial moisture level 70%, fructose (1% w/v), (NH4)2HPO4 (1% w/v), L-glutamine (1%w/v) and incubation period day 10. An overall 2.6-fold improvement in neomycin production was achieved due to optimization.

Electroless Ni–W–P Coating and Its Nano-WS2 Composite: Preparation and Properties

Abstract: The ternary alloy Ni–W–P and its WS2 nanocomposite coatings were successfully obtained on low-carbon steel using the electroless plating technique. The sodium tungstate (Na2WO4) concentration in the bath was varied to obtain Ni–W–P deposits containing various Ni and P contents. WS2 composite was obtained with a suitable concentration of Na2WO4 in Ni–P coating. These deposits were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX) studies. The corrosion behavior was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies in 3.5 wt % NaCl solutions, and the corrosion rates of the coatings for Ni–P, Ni–W–P, and Ni–W–P–WS2 were found to be 2.571 × 10–5, 8.219 × 10–7, and 7.986 × 10–7 g/h, respectively. An increase in the codeposition of alloying metal tungsten (W) enhanced the corrosion resistance and microhardness and changed the structure and morphology of the deposits. Incorporation of WS2 na...