Structural, Electrical, and Magnetic Properties of Zn Substituted Magnesium Ferrite

Zinc substituted magnesium (Mg–Zn) ferrites with the general formula Mg1−xZnxFe2O4 (x=0.00, 0.25, 0.50, 0.75, and 1.00) were prepared using the solution combustion route. The dried powder after calcination (700 °C for 2 h) was compacted and sintered at 1050 °C for 3 h. The structural, morphological, dielectric and magnetic properties of the sintered ferrites were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), impedance spectroscopy, and vibration sample magnetometry (VSM). The XRD analysis of sintered samples confirmed that the expected spinel cubic phase was formed for all samples. The crystallite sizes evaluated using Scherre's formula were found to be in the range of 47–80 nm. SEM analysis showed homogeneous grains with a polyhedral structure. The electrical conductivity increased with increasing frequency, which is normal dielectric behavior for such materials. The dielectric constant, dielectric loss tangent, and AC conductivity were found to be lowest for x=0.50. The VSM results showed that the zinc concentration had a significant influence on the saturation magnetization and coercivity

Synthesis, structural and transport properties of nanocrystalline La1−xBaxMnO3 (0.0≤x≤0.3) powders

Nanocrystalline La1−xBaxMnO3 (0.0≤x≤0.3) manganites have been prepared by a simple and instantaneous solution combustion method, which is a low temperature initiated synthetic route to obtain fine-grained powders with relatively high surface area. The phase purity and crystal structure of the combustion products are carried out by powder X-ray diffraction. The as-made nanopowders are in cubic phase. On calcination to 900 °C, barium doped manganites retain cubic phase, whereas barium free manganite transformed to rhombohedral phase. The scanning electron microscope (SEM) results revealed that the combustion-derived compounds are agglomerated with fine primary particles. The doped manganites have surface area in the range 24–44 m2/g. The surface area of the manganites increases with barium content, whereas it decreases on calcination. Both undoped and doped lanthanum manganites show two active IR vibrational modes at 400 and 600 cm−1. The low temperature resistivity measurements have been carried out by four-probe method down to 77 K. All the samples exhibit metal–insulator behaviour and metal–insulator transition temperature (TM–I) in the range 184–228 K and it is interesting to note that, as the barium content increases the TM–I shifts to lower temperature side. The maximum TM–I of 228 K is observed for La0.9Ba0.1MnO3 sample

Preliminary screening of cardamom (Elettaria cardamomum Maton) elite clones for thrips (Sciothrips cardamomi Ramk.) damage in the field

Seventy three elite cardamom (Elettaria cardamomum) clones were screened for tolerance to thrips (Sciothrips cardamomi) damage under natural infestation. Three colones, viz., D-514, D-769 and CI-754 were promising with least damage to capsules. &nbsp

Preliminary screening of cardamom (Elettaria cardamomum Maton) elite clones for thrips (Sciothrips cardamomi Ramk.) damage in the field

Seventy three elite cardamom (Elettaria cardamomum) clones were screened for tolerance to thrips (Sciothrips cardamomi) damage under natural infestation. Three colones, viz., D-514, D-769 and CI-754 were promising with least damage to capsules. &nbsp

Preliminary screening of cardamom (Elettaria cardamomum Maton) elite clones for thrips (Sciothrips cardamomi Ramk.) damage in the field

Seventy three elite cardamom (Elettaria cardamomum) clones were screened for tolerance to thrips (Sciothrips cardamomi) damage under natural infestation. Three colones, viz., D-514, D-769 and CI-754 were promising with least damage to capsules. &nbsp

Magnetoresistive studies on nanocrystalline la0.8Sr 0.2MnO3+δ manganite

Low-temperature magnetoresistance (MR) measurement has been carried out on nanocrystalline La0.8Sr0.2MnO3+δ manganites prepared by combustion synthesis. This preparation method yields voluminous powders with large surface area (â¼40m2/g) having crystalline nanosize(-50 nm) products. Formation and homogeneity of the solid solutions have been confirmed by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Rietveld refinement of X-ray data indicates that as-formed compound exhibits cubic phase with space group Pm3m. However, calcined sample transforms into rhombohedral phase with space group R-3c. The stabilization of the cubic phase in as-formed manganite is due to the substitution of Sr2+ on La3+ sites, resulting in higher Mn4+ content. The low-temperature resistivity measurements down to 70 K exhibit a broad metal-insulator transition (TM-I) at around 257 K. MR measurements on sintered pellets show â¼5 MR at 1T, whereas for 4 and 7T, the MR values are found as 22 and 28, respectively, at TM-I. © 2008 Elsevier B.V. All rights reserved

ANTIBACTERIAL ACTIVITY OF SYNTHESIZED SILVER NANOPARTICLES BY SIMAROUBAGLAUCA AGAINST PATHOGENIC BACTERIA

Objective: The present study outline the plant-mediated synthesis of silver nanoparticles (AgNPs) using leaf extract Simaroubaglauca, which act as both reducing and stabilizing agent.Methods: Formation of silver nanoparticles was confirmed by primarily by Ultraviolet/visible spectroscopy. X-ray diffraction studies revealed the crystallinity of the nanoparticles. The scanning electron microscopy was carried out to determine the mean particle size, as well as the morphology of the NPs and the composition of elements, was studied with Energy Dispersive X-ray analysis (EDS).Results: The silver nanoparticles were spherical in shape with a mean size of 23 nm. The EDS showed strong optical absorption peak at 3keV and it was confirmed the formation of AgNPs. The synthesised AgNPs further utilized for the evaluation of antibacterial activity and shown significant antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Enterobacter and Klebsiella pneumonia at 50 µg/ml and 100µg/ml concentrations.Conclusion: The synthesised silver nanoparticles have been characterised by UV-vis, SEM-EDAX and XRD to determine the sizes and shapes of the silver nanoparticles

Novel ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate derivatives: synthesis and anticancer activities

To explore the anticancer activity of 2, 4, 5, 6-substituted pyrimidines, several ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate derivatives associated with the different substituted aromatic/aliphatic carboxamides and sulfonamides were synthesized. Different groups and position on phenyl ring attached to the carboxamide and sulfonamide of the pyrimidine led to two set of compounds. Their chemical structures were confirmed by IR,1H NMR and LC/MS analysis. Cytotoxicity of all the synthesized compounds were examined on human leukemia celllines (K562 and CEM). The preliminary results showed most of the derivatives exhibited good antitumor activity. Compound with para chloro substitution among carboxamides and compound with meta dichloro substitution among sulphonamidesexhibited significant antitumor activity with IC50 value of 14.0 μM and 15.0 μM respectively against K562cell line. For comparison among electron donating groups between carboxamides and sulfonamides, compounds with para tert-butyl substitution were chosen for further studies. Cell cycle analysis suggests that both tert-butyl substituted compounds are able to induce apoptosis

CT-Scan study of crack patterns of fiber-reinforced concrete loaded monotonically and under low-cycle fatigue

Most fatigue models for concrete under compression assume, as an axiom, that compressive tests are a limit case for a cyclic test where failure is achieved in the first cycle. This is supported by the fact that the crack patterns obtained in both cases are similar to the naked eye. This paper focuses on verifying whether this observation is correct or not. For that, we used a Computed Tomography Scan together with digital image processing to obtain 3D damage maps of tested 40 mm edge-length cubes made of steel fiber-reinforced concrete. The cubes were classified in series according to the type of loading: intact, monotonic and cyclic. They were scanned to acquire their 3D damage maps. Additionally, a specific post-processing algorithm was developed by the authors to compare the different crack patterns. The results show that average damage maps for monotonically and cyclically-tested cubes are statistically similar, thereby confirming the initial hypothesis for steel fiber-reinforced concrete. Furthermore, damage distribution near the platens apparently depends on whether it is a fixed platen or it is adjustable to the specimen surface due to a spherical seat.Ministerio de Economía y Competitividad, Spain, under grants BIA2015-68678-C2-1-R and BIA2015-68678-C2-2-