Strain mediated enhancement in magnetoelectric properties of sonochemically synthesized piezoelectric and piezomagnetic composites

Materials with magneto-electric (ME) properties are of great importance because of their demand in electronic industries. Three dimensional nano-particles of the ME-composites having the general formula (1-x)CoCr_0.3Fe_1.7O₄(CCFO)+(x)BaTiO₃(BTO) (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were obtained by comprising the piezoelectric-BTO and piezomagnetic-CCFO phases. The individual phases of CCFO and BTO were synthesized separately by ultrasonic irradiation assisted sonochemical and sol-gel routs. X-ray diffraction patterns (XRD) confirmed the well-crystalline nature of both the phases. BTO and CCFO phases were under tensile strain as confirmed by the variation in lattice constants with varying proportion of BTO and CCFO. An energy-dispersive X-ray spectroscopy spectrum confirmed the phase purity of the samples and stoichiometric concentration of elements. Magnetic properties were investigated by M ? H loop measurements and dielectric properties by using RF impedance analyzer. Dielectric constant increased with the increasing percentage of BTO. The maximum value of ME coefficient (24.7 mV/cm?Oe) is observed for the 60%CCFO+40%BTO sample. The obtained results were discussed in the light of grain size, strain and the basic properties of the individual phases. The prepared materials can be applicable in electronic devices where high magneto-electric coefficient is desirable.     

Cotton linter nano-fibers as the potential reinforcing agent for guar gum

Cotton linter nano-fibers (CLNFs) were prepared from cotton linters by a refining process. The prepared CLNFs were characterized for morphology, crystallinity and degree of polymerization. CLNF was used as a reinforcing agent in guar gum to improve its performance properties. Guar gum/CLNF nanocomposite films were prepared by a solution-casting process. CLNF was added in concentrations of 0.1, 0.25, 0.5 and 1.0 % (w/w) in guar gum. The prepared guar gum/CLNF nano-composite films were characterized for mechanical, thermal, rheological, crystallinity, water vapor transmission rate (WVTR) and light transparency properties. The enthalpy of melting and melting temperature of guar gum increased with increased concentration of CLNF; but up to 0.25 % (w/w) concentration, above which they started decreasing. Tensile strength and Young’s modulus of guar gum increased by 32 and 35 %, respectively, by 0.25 % (w/w) addition of CLNF; however, it decreased on further increase in the concentration of CLNF. The percentage elongation at break and WVTR decreased by 58 and 57 % for 0.25 % (w/w) CLNF-added guar gum. The observed improvements in the properties were due to better interaction between CLNF and guar gum. CLNF was found to have uniformly dispersed in guar gum on addition up to 0.25 % concentration; however, it started forming aggregates at higher concentration, as evident from scanning electron microscopy. Viscosity increased, whereas transparency decreased with increased concentration of CLNF in guar gum.     

Hardystonite improves biocompatibility and strength of electrospun polycaprolactone nanofibers over hydroxyapatite: A comparative study

The aim of this study was to compare physico-chemical and biological properties of hydroxyapatite (HA) and hardystonite (HS) based composite scaffolds. Hardystonite (Ca₂ZnSi₂O₇) powders were synthesized by a sol–gel method while polycaprolactone–hardystonite (PCL–HS) and polycaprolactone–hydroxyapatite (PCL–HA) were fabricated in nanofibrous form by electrospinning. The physico-chemical and biological properties such as tensile strength, cell proliferation, cell infiltration and alkaline phosphatase activity were determined on both kinds of scaffolds. We found that PCL–HS scaffolds had better mechanical strength compared to PCL–HA scaffolds. Addition of HA and HS particles to PCL did not show any inhibitory effect on blood biocompatibility of scaffolds when assessed by hemolysis assay. The in vitro cellular behavior was evaluated by growing murine adipose-tissue-derived stem cells (mE-ASCs) over the scaffolds. Enhanced cell proliferation and improved cellular infiltrations on PCL–HS scaffolds were observed when compared to HA containing scaffolds. PCL–HS scaffolds exhibited a significant increase in alkaline phosphatase (ALP) activity and better mineralization of the matrix in comparison to PCL–HA scaffolds. These results clearly demonstrate the stimulatory role of Zn and Si present in HS based composite scaffolds, suggesting their potential application for bone tissue engineering.     

Synthesis,characterization and electrical properties of the system LaMnxFe1−xO3

The system manganese substituted lanthanum ferrite viz. LaMn_xFe_1?xO₃ (1.0 ≤ x ≥ 0) was prepared by sol–gel autocombusion method. The structural characterization of the samples was carried out by X-ray diffraction technique and it is found that, the phase transfer from cubic to orthorhombic perovskite structure. The lattice parameter and crystallite size decrease with increasing Mn content. The phase formation of perovskite was revealed by thermal analysis technique. The surface morphology and elemental analysis of all the samples were carried out by scanning electron microscopy and energy dispersive X-ray spectroscopic technique, respectively. Electrical properties of the compounds show that, they exhibit semiconducting behavior. The substitution of manganese ions plays an important role in changing their structural, electrical and magnetic properties of lanthanum ferrite.     

Micellization and Clouding Behavior of EO–PO Block Copolymer in Aqueous Salt Solutions

Aqueous solution properties of polyethylene oxide–block-polypropylene oxide–block-polyethylene oxide TBP [(PEO)₁₀₃(PPO)₃₉(PEO)₁₀₃] were studied in the presence of sodium salts with different anions (NaI, NaBr, NaCl, NaF, Na₂SO₄, Na₃PO₄) to investigate unimer-to-micelle transition [critical micelle concentration (CMC), critical micellization temperature (CMT)], micelle size and the phase separation (cloud point). This TBP, due to its very hydrophilic (80% PEO) nature does not form micelles at ambient temperatures. Micellization can be induced much below its CMT in water on addition of sodium salts having different anions. Analytical methods viz. fluorescence, FTIR and dynamic light scattering (DLS) were used to monitor the salt-induced micellization. The hydration of respective anion and resultant contribution to its salting-out effect was found to be the governing factor in promoting micellization. The presence of salt decreases the CMC, CMT and phase separation temperature. The salts affect the aggregation process in agreement with an order mentioned in Hofmeister series.     

Recent developments in nanotechnology transforming the agricultural sector: a transition replete with opportunities

The applications and benefits of nanotechnology in the agricultural sector have attracted considerable attention, particularly in the invention of unique nanopesticides and nanofertilisers. The contemporary developments in nanotechnology are acknowledged and the most significant opportunities awaiting the agriculture sector from the recent scientific and technical literature are addressed. This review discusses the significance of recent trends in nanomaterial‐based sensors available for the sustainable management of agricultural soil, as well as the role of nanotechnology in detection and protection against plant pathogens, and for food quality and safety. Novel nanosensors have been reported for primary applications in improving crop practices, food quality, and packaging methods, thus will change the agricultural sector for potentially better and healthier food products. Nanotechnology is well‐known to play a significant role in the effective management of phytopathogens, nutrient utilisation, controlled release of pesticides, and fertilisers. Research and scientific gaps to be overcome and fundamental questions have been addressed to fuel active development and application of nanotechnology. Together, nanoscience, nanoengineering, and nanotechnology offer a plethora of opportunities, proving a viable alternative in the agriculture and food processing sector, by providing a novel and advanced solutions. © 2017 Society of Chemical Industry     

Nutritional composition, processing, and utilization of horse gram and moth bean

Horse gram and moth bean are the unexploited legumes of the tropics and subtropics grown mostly under dry-land agriculture. The chemical composition is comparable with commonly cultivated legumes. Like other legumes, these are deficient in methionine and tryptophan. Horse gram is an excellent source of iron and molybdenum. Comparatively, horse gram seeds have higher trypsin inhibitor and hemagglutinin activities and polyphenols than moth bean seeds. Dehusking, germination, cooking, and roasting have been shown to produce beneficial effects on nutritional quality of both the legumes. Both the legumes require prolonged cooking to obtain product of acceptable nature. A soak solution (1.5% NaHCO3 + 0.5% Na2CO3 + 0.75% citric acid) treatment has been shown to reduce cooking time and improve protein quality. Moth bean is mostly consumed as dhal or sprouts. The whole seeds of horse gram are generally utilized as cattle feed. However, it is consumed as a whole seed, sprouts, or whole meal by a large population in rural areas of southern India. Medical uses of these legumes have been discussed.