Ultra-compact with improved data rate optical encoder based on 2D linear photonic crystal ring resonator

Photonic Network Communications - In the present work, a high-speed optical encoder is proposed based on two-dimensional photonic crystal ring resonator using coupled mode theory and resonance...     

Conformal Band Notched Circular Monopole Antenna Loaded with Split Ring Resonator

This article presents the design and analysis of conformal circular monopole antenna with split ring resonator to get frequency notch characteristics in the wideband. Split ring resonators placed on one side of the substrate and complementary split ring resonators placed on the other side of the substrate at defected ground structure, which yields the frequency notch characteristics with respect to the microstrip feeding. Dual notch band characteristics are obtained between 4–4.3 and 7.3–8.1 GHz. The analyzed conformal characteristic of the antenna supports excellent constant reflection coefficient characteristics over the band at different angles. The impedance and radiation characteristics of the antenna model is analysed in simulation along with unit cell analysis of the SRR and the measured results are providing good agreement with them.     

Polyol process for the synthesis of LiFePO4 rhombohedral particles

As a new approach, LiFePO₄ nanoparticles were directly synthesized from precursors iron(III) nitrate and lithium dihydrogen phosphate by a polyol process without post heat treatment in one step. The obtained powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and combined thermogravimetry and differential scanning calorimetry and mass spectroscopy TG/DSC/MS. The X-ray diffraction showed the orthorhombic crystal structure of LiFePO₄ without any impurity phases. The synthesized LiFePO₄ has rhombohedral morphology with high aspect ratio with a thickness of less than 100 nm. TG/DSC/MS revealed a weight loss of only 10.9 wt.% when heating up to 1000 °C. Electrodes prepared from the LiFePO₄ particles were electrochemically characterized by cycling at 0.1C current rate and temperatures in half cell measurements against lithium foil between 2 and 4.2 V in an EC/DMC electrolyte with 1 M LiPF₆ as conductive salt. A reversible specific capacity of 146 mAh/g was achieved by applying carbon coating on the rhombohedral particles.     

Formation of corn fiber gum-milk protein conjugates and their molecular characterization

Corn fiber arabinoxylan is hemicellulose B isolated from the fibrous portions (pericarp, tip cap, and endosperm cell wall fractions) of corn kernels and is commonly referred to as corn fiber gum (CFG). Our previous studies showed that CFG isolated from corn bran (a byproduct of corn dry milling) contains very little protein and is an inferior emulsifier for oil-in-water emulsion systems as compared to corn fiber gum isolated from corn fiber derived from the corn wet-milling process. The protein deficient CFG isolated from corn bran was covalently conjugated with byproducts of cheese processing, β-lactoglobulin (β-LG) and whey protein isolate (WPI) using an economical food-grade Maillard-type heating reaction for the purpose of increasing their commercialization potential as a food emulsifier and soluble nutritional additive in beverages. The formation of the CFG-protein conjugates has been confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). It has also been demonstrated that CFG-protein conjugates are capable of producing fine emulsions with better stability than either CFG or protein alone. The molecular characterization of CFG-protein conjugates was performed by high-performance size-exclusion chromatography (HPSEC) coupled to on-line multi-angle laser light scattering and viscometric detection. The analysis by HPSEC revealed that CFG-protein conjugates had higher weight-average molar mass (M_w, 340-359 kDa) and polydispersity (M_w/M_n, 1.74) than the corresponding unconjugated CFG (M_w, 290 kDa and M_w/M_n, 1.35). The z-average root-mean-square radius of gyration (R_gz) of CFG-protein conjugates was slightly higher (30.5-33.5 nm) in comparison to CFG (29.5 nm) but their weight-average-intrinsic viscosity (η) remained unchanged (about 1.32 dL g⁻¹). The Mark-Houwink exponent “a” of conjugates (0.40) was lower than the unconjugated CFG (0.53) indicating the formation of a more compact structure after conjugation with protein. These findings should benefit the beverage industry, which can use this information to produce a high quality emulsifier from the low-value byproducts of corn dry milling and cheese processing.     

Food security in a remittance based economy

We interviewed 395 subsistence farming households from Chitwan, Nepal in order to identify the impact of remittances and other explanatory variables on child, adult, and household food security. The highest category of the IV - ordered probit regression models with cluster robust standard errors indicated that the food security status of households, adults and children was explained by gender and age of household head, adoption of conservation agricultural technology, number of fruit trees, and income from agricultural and livestock sources. Additional variables affecting only children’s food security were the adoption of hybrid rice or maize varieties and the wage income or salary earned within the district, whereas an additional variable affecting only household and adult food security was the wage income earned outside the district. Households receiving international remittances were more food secure than those households that did not receive such remittances.     

Numerical study of hydrogen explosions in a refuelling environment and in a model storage room

Numerical simulations have been carried out for large scale hydrogen explosions in a refuelling environment and in a model storage room. For the first scenario, a high pressure hydrogen jet released in a congested refuelling environment was ignited and the subsequent explosion analysed. The computational domain mimics the experimental set up for a vertical downwards release in a vehicle refuelling environment experimentally tested by Shirvill et al. [6]. For completeness of the analysis, an analytical model has also been developed to provide the transient pressure conditions at nozzle exit. The numerical study is based on the traditional computational fluid dynamics (CFD) techniques solving Reynolds averaged Navier-Stokes equations. The Pseudo diameter approach is used to bypass the shock-laden flow structure in the immediate vicinity of the nozzle. For combustion, the Turbulent Flame Closure (TFC) model is used while the shear stress transport (SST) model is used for turbulence. In the second scenario, premixed hydrogen-air clouds with different hydrogen concentrations from 15% to 60% in volume were ignited in a model storage room. Analysis was carried out to derive the dependence of overpressure on hydrogen concentrations for safety considerations.     

Effect of electrolyte pH on the structure andin vitro osteoblasts response to anodic titanium oxide

This study examines the surface morphology, microstructure, and chemical composition of titanium surfaces treated by anodic spark oxidation in phosphate buffer solution at pH 2, 7 and 12. The pH of the electrolyte was found to play a substantial role in the formation of different morphologies, chemical compositions, and pore dimensions with microporous structures. SEM revealed variation in the topologies of the anodized surface with electrolyte pH. Porous structures with uniform pores and high roughness were obtained in pH 12 solutions. However, intense anatase crystal was obtained at pH 7. The relationship between surface characteristics of titanium and initial interactions of titanium-osteoblasts was also in vestigated. Our findings demonstrated the cell viability and proliferation on the anodic oxides produced at pH 12 to be superior to those produced at pH 2 and 7 as well as on the control titanium surface. This study also provides evidence of enhanced osteoblast adhesion on anodized metal substrates under in vitro conditions.     

On the role of mass transport in high rate dissolution of iron and nickel in ECM electrolytes—I. Chloride solutions

High rate anodic dissolution of iron and nickel in 5 M NaCl was studied in a flow channel cell under controlled hydrodynamic conditions. Galvanostatic experiments were aimed at investigating the influence of current density and electrolyte flow rate on anode potential, current efficiency for metal dissolution and surface texture resulting from dissolution. Active dissolution at low current densities leads to surface etching and transpassive dissolution at high current densities leads to surface brightening. Transition from active to transpassive dissolution is mass transport controlled and is accompanied by a change in anode potential, surface microtexture and in case of iron by a change in the valence of metal dissolution.