Superparamagnetic bimetallic iron-palladium nanoalloy: synthesis and characterization

Iron-palladium nanoalloy in the particle size range of 15-30?nm is synthesized by the relatively low temperature thermal decomposition of coprecipitated [Fe(Bipy)(3)]Cl(2) and [Pd(Bipy)(3)]Cl(2) in an inert ambient of dry argon gas. The silvery black Fe-Pd alloy nanoparticles are air-stable and have been characterized by EDX-RF, XRD, AFM, TEM, magnetometry, (57)Fe M?ssbauer and impedance spectroscopy. This Fe-Pd nanoalloy is in single phase and contains iron sites having up to 11 nearest-neighboring atoms. It is superparamagnetic in nature with high magnetic susceptibility, low coercivity and hyperfine field.     

Effect of radiation and soaking on trypsin inhibitor and protein content of chickpea (Cicer arientinum L.)

Composition of Ascochyta-blight resistant chickpea for proximate components, vitamins, energy and trypsin inhibitor, was determined. The influence of irradiation and soaking at ambient temperatures (25–35°C) on trypsin inhibitor activity (TIA) and protein content of chickpea, was investigated. A significant linear relation (r = ?0.960 to ?0.987) was found between the loss of TIA and soaking time of irradiated and unirradiated seeds (p < 0.05) and the rate of loss increased with increasing radiation dose (0.25–1.00 kGy). However, effect of radiation alone was negligible. Maximum decrease (30.7%) in TIA (from 330.0 to 228.6 TIU/g) occurred during soaking for 12 h of 1.00 kGy sample. The protein contents increased from an initial value of 21.7% to 23.4% and 22.7% as a result of soaking for 12 h in tap and distilled waters respectively. Radiation treatment exhibited little or no effect.     

Sorption potential of rice husk for the removal of 2,4-dichlorophenol from aqueous solutions: kinetic and thermodynamic investigations

The sorption potential of chemically and thermally treated rice husk (RHT) for the removal of 2,4-dichlorophenol (DCP) from aqueous solutions has been investigated. Sorption of DCP by rice husk was observed over a wide pH range of 1-10. The effect of contact time between liquid and solid phases, sorbent dose, pH, concentration of sorbate and temperature on the sorption of DCP onto rice husk has been studied. The pore area and average pore diameter of RHT by BET method are calculated to be 17+/-0.6 m2g-1 and 51.3+/-1.5 nm, respectively. Maximum sorption (98+/-1.2%) was achieved for RHT from 6.1x10(-5) moldm(-3) of sorbate solution using 0.1g of rice husk for 10 min agitation time at pH 6 and 303K, which is comparable to activated carbon commercial (ACC) 96.6+/-1.2%, but significantly higher than chemically treated rice husk (RHCT) 65+/-1.6% and rice husk untreated (RHUT) 41+/-2.3%. The sorption data obtained at optimized conditions was subjected to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Sorption intensity 1/n (0.31+/-0.01) and sorption capacity multilayer C(m) (12.0+/-1.6 mmolg(-1)) have been evaluated using Freundlich sorption isotherm, whereas the values of sorption capacity monolayer Q (0.96+/-0.03 mmolg(-1)) and binding energy, b, (4.5+/-1.0)x10(4)dm(3)mol(-1) have been estimated by Langmuir isotherm. The Langmuir constant, b, was also used to calculate the dimensionless factor, R(L), in the concentration range (0.6-6.1)x10(-4) moldm(-3), suggesting greater sorption at low concentration. D-R sorption isotherm was employed to calculate sorption capacity X(m) (2.5+/-0.07 mmolg(-1)) and sorption energy E (14.7+/-0.13 kJmol(-1)). Lagergren and Morris-Weber equations were employed to study kinetics of sorption process using 0.2g of RHT, 25 cm(3) of 0.61x10(-4)moldm(-3) sorbate concentration at pH 6, giving values of first-order rate constant, k, and rate constant of intraparticle transport, R(id), (0.48+/-0.04 min(-1) and 6.8+/-0.8 nmolg(-1)min(-1/2), respectively) at 0.61x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT, pH 6 and 2-10min of agitation time. For thermodynamic studies, sorption potential was examined over temperature range 283-323 K by employing 6.1x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT at pH 6 and 10 min of agitation time and values of DeltaH (-25+/-1 kJmol(-1)), DeltaS (-61+/-4 Jmol(-1)K(-1)) and DeltaG(303K) (-7.1+/-0.09 kJmol(-1)) were computed. The negative values of enthalpy, entropy, and free energy suggest that the sorption is exothermic, stable, and spontaneous in nature.     

Removal and recovery of uranium from aqueous solutions by Trichoderma harzianum

Removal and recovery of uranium from dilute aqueous solutions by indigenously isolated viable and non-viable fungus (Trichoderma harzianum) and algae (RD256, RD257) was studied by performing biosorption-desorption tests. Fungal strain was found comparatively better candidate for uranium biosorption than algae. The process was highly pH dependent. At optimized experimental parameters, the maximum uranium biosorption capacity of T. harzianum was 612 mg U g(-1) whereas maximum values of uranium biosorption capacity exhibited by algal strains (RD256 and RD257) were 354 and 408 mg U g(-1) and much higher in comparison with commercially available resins (Dowex-SBR-P and IRA-400). Uranium biosorption by algae followed Langmuir model while fungus exhibited a more complex multilayer phenomenon of biosorption and followed pseudo-second-order kinetics. Mass balance studies revealed that uranium recovery was 99.9%, for T. harzianum, and 97.1 and 95.3% for RD256 and RD257, respectively, by 0.1M Hydrochloric acid which regenerated the uranium-free cell biomass facilitating the sorption-desorption cycles for better economic feasibility.     

Self-propagating high temperature synthesis of MoSi2 matrix composites

MoSi2 is presently regarded as the most important material for electrical heating and as one with huge potential for high temperature structural uses. MoSi2 and MoSi2 matrix composites were prepared by self-propagating high temperature synthesis （SHS）. Pure MoSi2 was obtained and a compound of MoSi2 and WSi2was synthesized in the form of predominant solid solution （Mo,W）Si2. By adding aluminum of 5.5 at.% to Mo-Si, the crystal structure of MoSi2 changed into a mixture of tetragonal Cllb MoSi2and hexagonal C40 Mo（Si,Al）2. The （Mo,W）Si2-Mo（Si,Al）2-W（Si,Al）2 composite materials were synthesized by adding aluminum of 5.5 at.% to Mo-W-Si. However, if the amount of the added aluminum was not larger than 2.5 at.%, it did not have any significant effect. SHS is an effective technology for synthesis of MoSi2 and MoSi2 matrix composites.     

Exploiting encapsulated Himalayan walnut oil as a vivid source of essential fatty acids for the development of novel functional bread

The basic aim of the study was to utilise Himalayan Walnut oil (HWO) encapsulated in soy protein isolate (SPI)–maltodextrin (MD)–pectin (Pec) complex as a potential source of omega fatty acids for bread fortification. Encapsulated HWO was integrated with bread for enhanced quality and technological aspects compared to control: it contained protein (9–19%), fat (6–8%), alpha-linolenic acid (37.50%) with lower carbohydrate (35–42%) content. The baked loaves depicted higher specific loaf volume (3.85–4.85 cm³ g⁻¹) with low hardness (4.24–5 N) due to the presence of hydrocolloids. Crust and crumb colour revealed a significant effect on the appearance of bread, with an increase in the antioxidant activity as assessed by 1,1-diphenyl-2-picrylhydrazyl (80%), 2,2′-Azino-bis (3-Ethylbenzothiazoline-6-Sulfonic Acid) (100%) and Metal Chelating Activity (10%). Compared to control, addition of encapsulated HWO increased final product quality by lowering oil oxidation during storage period. Scanning electron microscopic analysis showed intact encapsulated oil bodies in crumb after baking, thereby demonstrating high omega fatty acid retention.     

An exploration of 3-methoxypropionitrile chemical sensor based on layered hexagonal NiCo2O4 nanoplates as electrode material

Binary metal oxide, nickel-cobalt oxide (NiCo₂O₄), was hydrothermally synthesized for the successful utilization as electrochemical electrode in chemical sensor. Benefited from the large surface area, binary NiCo₂O₄ stacked hexagonal nanoplates (HNPs) based electrode was utilized for the electrochemical sensing application towards teratogenic chemical i.e. 3-methoxypropionitrile (3-MPN). The sensing results displayed a reproducible sensitivity of ~605 μAμM^?1cm^?2, detection limit of ~11.8 μM with the correlation coefficient (R) of ~0.99502 and good linearity from ~10 μM to ~100 μM. Stability and repeatability of binary NiCo₂O₄ stacked HNPs based electrode was investigated with satisfactory results. Our synthesized binary NiCo₂O₄ stacked HNPs based electrode is promising for sensor applications and thus, enlightens the possibility of synthesizing other binary oxide materials.     

Enhanced non-linear optical properties of Eu3+ activated glasses by embedding silver nanoparticles

Tri-positive lanthanide ion (Eu³⁺) activated glasses doped with different concentrations of silver (Ag0₎ nanoparticles obtained using thermal reducing agent were fabricated by applying the method of melt quench. The formation of Ag⁰ nanoparticles in glasses was revealed by the surface plasmon resonance (SPR) peak in the absorption spectra. Transmission electron microscopic measurements confirmed the presence of spherically shaped Ag⁰ nanoparticles of different size distribution. The absorption spectra showed a red–shift of the SPR peak with an increase in AgNO₃ concentration occurring through Ostwald's ripening process because of the growth of particle size (as evidenced from microscope images). The non-linear optical (NLO) and optical limiting measurements were performed in the near infrared spectral region and femtosecond pulse excitation. The non-linear parameters were found to increase as the AgNO₃ concentration increased to 0.6 mol %, however, the parameters subsequently decreased at higher doping level. The optical limiting threshold values demonstrated a reverse trend. The increase in non-linear optical properties regarding Ag nanoparticles concentration attributed to the enhancement of polarizabilities of glasses that occurred through local field stimulated by SPR of Ag nanoparticles when exposed to laser radiation of high energy. The increase in NLO coefficients (particularly the non-linear absorption coefficient) and the decrease in optical limiting threshold values with AgNO₃ concentration (up to 0.6 mol %) indicated that these glasses containing 0.6 mol % AgNO₃ are useful for the construction of the power optical limiters that function at the infrared region in the femtosecond pulse regime.     

Synthesis of manganese (IV) oxide at activated carbon on reduced graphene oxide sheets via laser irradiation technique for organic binder-free electrodes in flexible supercapacitors

We report a novel, green, scalable technique to synthesize binder-free, high-purity conductive composite comprising activated carbon (AC), manganese dioxide nanorods (MnO₂), and reduced graphene oxide sheets (rGO) for flexible supercapacitors with outstanding electrochemical performance. UV pulsed laser irradiation of GO-based composite dispersion (AC/GO or MnO₂@AC/GO) in ethanol aqueous medium was used to induce a photocatalytic reduction of GO and simultaneous anchor AC particles or AC loaded MnO₂ nanorods (MnO₂@AC) on the reduced GO sheets (rGO) at room temperature and atmospheric pressure. rGO sheets serve as a large surface area, conductive binder to enhance the ion adsorption, electrical conductivity, and mechanical flexibility of supercapacitor electrodes. This laser-induced photocatalytic reduction method was used to prepare two different rGO-based colloidal composites AC/rGO (CG) and MnO₂@AC/rGO (MCG). The prepared rGO-based colloidal composites were used to fabricate symmetric supercapacitors (CG//CG and MCG//MCG) and asymmetric supercapacitors (MCG//CG) in which MCG is the positive electrode and CG is the negative one. All prepared rGO-based supercapacitors demonstrated significant improvement in their electrochemical performance compared with rGO-free AC based supercapacitors. The enhancement in the electrochemical properties of rGO-based supercapacitors could be attributed to the intrinsic characteristics of rGO, such as high surface area, excellent electrical conductivity, and super mechanical flexibility. Our approach is a one-step, scalable, cost-effective synthesis technique to produce all binder-free AC/rGO based composites for flexible energy-storage devices.     

Pressure mode decomposition analysis of the flow past a cross-flow oscillating circular cylinder

Journal of Mechanical Science and Technology - Proper orthogonal decomposition (POD) is often employed in developing reduced-order models (ROM) in fluid flows for design, control, and optimization....