Poly(ethylene terephthalate)/clay nanocomposites with trisilanolphenyl polyhedral oligomeric silsesquioxane as dispersant: simultaneously enhanced reinforcing and stabilizing effects

This paper presents a new approach for the preparation of poly(ethylene terephthalate) (PET)/clay nanocomposites using surfactant‐free clay (sodium montmorillonite, Na‐MMT) with trisilanolphenyl polyhedral oligomeric silsesquioxane (Tsp‐POSS) as dispersant. The dispersion of clay in the PET/Na‐MMT/Tsp‐POSS nanocomposites is enhanced over that in PET/Na‐MMT by using a very small amount of Tsp‐POSS, which acts as functional spacer to keep clay platelets apart and pull monomers in, and, at the same time, acts as a PET chain extender. As a result, thermomechanical properties and thermo‐oxidative stability of PET/Na‐MMT/Tsp‐POSS are improved simultaneously compared with those of PET/organoclay nanocomposites. © 2013 Society of Chemical Industry     

Dengue NS1 Detection used Chemically Modified Porous Silicon Microcavity (PSMC)

Porous silicon is an adaptable platform for developing label-free biosensors with high sensitivity and low cost. Dengue viral infection is detected based on commercially available ELISA (Enzyme-linked immunosorbent assay) based serological assays and not on the more difficult and costly procedures of Haemagglutination inhibition (HI), virus isolation or RT-PCR (Real Time polymerase chain reaction). In this paper, a novel diagnostic method for the detection of Dengue virus has been developed because it is still blooming and is becoming a major health concern around the world. Fabrication of a silicon wafer to create a Porous Silicon Microcavity (PSMC) has been used to increase the surface area for the immune reaction and hence the probability of the Dengue virus detection after chemical modification with adhesives and bio-functionalization is high by the treatment of antibody and antigen. Finally, a specific antigen-antibody reaction was obtained.     

Characterization of the heat transfer accompanying electrowetting or gravity-induced droplet motion

Electrowetting (EW) involves the actuation of liquid droplets using electric fields and has been demonstrated as a powerful tool for initiating and controlling droplet-based microfluidic operations such as droplet transport, generation, splitting, merging and mixing. The heat transfer resulting from EW-induced droplet actuation has, however, remained largely unexplored owing to several challenges underlying even simple thermal analyses and experiments. In the present work, the heat dissipation capacity of actuated droplets is quantified through detailed modeling and experimental efforts. The modeling involves three-dimensional transient numerical simulations of a droplet moving under the action of gravity or EW on a single heated plate and between two parallel plates. Temperature profiles and heat transfer coefficients associated with the droplet motion are determined. The influence of droplet velocity and geometry on the heat transfer coefficients is parametrically analyzed. Convection patterns in the fluid are found to strongly influence thermal transport and the heat dissipation capacity of droplet-based systems. The numerical model is validated against experimental measurements of the heat dissipation capacity of a droplet sliding on an inclined hot surface. Infrared thermography is employed to measure the transient temperature distribution on the surface during droplet motion. The results provide the first in-depth analysis of the heat dissipation capacity of electrowetting-based cooling systems and form the basis for the design of novel microelectronics cooling and other heat transfer applications.     

Highly stabilized Ag2O-loaded nano TiO2 for hydrogen production from glycerol: Water mixtures under solar light irradiation

Nano TiO₂ prepared by a hydrothermal method and silver-loaded nano TiO₂ prepared by impregnation were studied for the photocatalytic production of hydrogen from glycerol:water mixtures. The structural characteristics were revealed using XRD, EDAX, DRS, TEM, XPS, BET surface area and Raman techniques. The photocatalytic hydrogen production has been investigated under solar light irradiation. Effects of nano TiO₂ calcination temperature, silver loading, photocatalyst content, light source and Ag oxidation state on hydrogen production have been systematically studied. Maximum hydrogen production of 200 μmol h^?1 g^?1 is observed on 4wt% silver-loaded nano TiO₂ catalyst in pure water and the maximum hydrogen production of 7030 μmol h^?1 g^?1 is observed on 3wt% silver-loaded nano TiO₂ catalyst in glycerol: water mixtures. Silver-loaded nano TiO₂ reduced and photodeposited catalysts show similar hydrogen production activities in glycerol: water mixtures under solar irradiation. The optimum catalyst modified with conducting carbon materials (graphene oxide, graphene, carbon nanotubes) by a solid-state dispersion method were also studied for hydrogen production under solar light irradiation. Compared with pure nano TiO₂, a 3wt% silver-loaded nano TiO₂/graphene composite exhibited an approximately 17-fold enhancement of hydrogen production leading to hydrogen production rates of 12,100 μmol h^?1 g^?1. Based on the characterization results and hydrogen production activity on these catalysts, a structure–activity correlation has been proposed wherein the interacting Ag₂OAg phases on the surface of nano TiO₂ play an important role in maintaining a high hydrogen production activity under solar irradiation.     

Nanotechnology in Agri-Food Sector

The emergence of nanotechnology developments using nanodevices/nanomaterials opens up potential novel applications in agriculture and food sector. Smart delivery systems, biosensors, and nanoarrays are being designed to solve the problems faced in agriculture sector. Similarly, food sector is also benefited through the use of smart biosensors, packaging materials, and nanonutraceuticals. Despite the great potential of nanotechnology in agri-food sector, people are ambiguous about use in food applications because of suspected potential health risks and environmental concerns. Nanoparticles, due to their unique characteristics, including small size, shape, high surface area, charge, chemical properties, solubility and degree of agglomeration can cross cell boundaries or pass directly from the lungs into the blood stream and ultimately reach to all of the organs in the body. This is the reason why they may pose higher risk than the same mass and material of larger particles. In this paper, we have made an attempt to give an overview of nanotechnology developments in agri-food sector, risks associated with nanomaterials and toxicity regulations for policy framework.     

Dielectric spectroscopy-based characterisation of different types of Paneer (Indian cottage cheese) in terms of texture,microstructure and functional groups

Different variants of Paneer were prepared with cow milk (CM), buffalo milk (BM), skimmed milk powder (SMP) and blends (40:60, 50:50, 60:40) of SMP with CM/BM. The Paneer composition, texture, microstructure and spread of functional groups were correlated with the dielectric capacitance values. Results depicted a strong correlation (R² > 0.95) between milk used for Paneer making and its proximate composition in terms of the capacitance value, and it was highest for CM followed by BM; 100% SMP Paneer recorded lowest values. Paneer made from blends of SMP and liquid milk had the lowest transmittance value, indicating higher total protein content.     

Preparation of microwave-processed oil-free potato snacks with assorted natural flavours: Application of advanced chemometrics

Generally, potato chips are produced by deep-fat frying with 35%–40% oil in the final product, which is considered unhealthy. Therefore, we attempted to prepare microwave-processed oil-free potato snacks, fat-free alternative for potato chips, assorted with natural flavours (tomato, mint and pepper) and evaluated their proximate composition, microbiological analysis and sensory evaluation coupled with advanced chemometrics. The proximate analysis revealed the presence of carbohydrates (53–58 g/100 g), energy (190–214 kcal/100 g) and negligible fat (≤0.15%) with a microbial load of 2.50–9 CFU/100 g. Samples assorted with mint and tomato flavours received higher sensory scores (7.65–8.80) for all sensory attributes compared with control (6.61–7.55). From the chemometric analysis, the high similarities in samples assorted with mint and tomato flavours confirmed by principal component analysis loadings of 0.69 and 0.71, respectively, and hierarchical clustering (cluster 1 with 2 sub-clusters). Therefore, the microwave processing can be a suitable technique to produce oil-free potato snacks with natural flavourings while preserving their quality attributes.     

Effect of soil moisture stress from flowering to grain maturity on functional properties of Sri Lankan rice flour

Functional properties of flour from rice variety BG 250 (short‐season) and BG 359 (long‐season) exposed to soil water stress from flowering to grain maturity were investigated. Protein content was reduced in both varieties but lipid was reduced only in BG 359 in response to soil moisture stress. AAM content decreased in BG 250 but unaffected in BG 359. Water stress increased swelling power, onset of pasting, peak viscosity, granular breakdown, gel hardness, and cohesiveness in both varieties. Gelatinization temperatures in both varieties were unaffected by water stress, while gelatinization enthalpy was increased in BG 359 but unchanged in BG 250. A double endotherm (type I and type II) appeared in AM–lipid complex in all the flour samples. Type I AM–lipid complex was reduced in BG 359 in response to water stress. Only a single endotherm appeared in the re‐formed AM–lipid complex in gelatinized starch. The magnitude of the ΔH of re‐formed AM–lipid complex was reduced in BG 359 in response to soil moisture stress, but unaffected in BG 250. Water stress decreased AP retrogradation in BG 359 while it was unaffected in BG 250.     

Beta Vulgaris root as a natural food colouring in doughnut: Dough rheological properties and bioactive composition

In the present study, the influence of Beta vulgaris root powder (BVP) incorporated at 0%, 5%, 7.5%, 10% and 12.5% levels on the empirical and fundamental rheological characteristics; dough texture properties; nutritional and bioactive components in the doughnut were carried out. The addition of BVP, decreased the WAC (58.4%–51.2%), DDT (6.19–1.31 min), extensibility (148–95 mm), and springiness (4.56–3.24 N) and viscosity parameters to varying extent. The frequency sweep test indicated that both the dynamic moduli increased and G' was higher than G" at all levels indicating the solid elastic structure of the dough. The dimensional characteristics of the doughnuts indicated a decrease in volume (103.3–85 mL) and an increase in weight (35.8–46.7 g) and compression force (11.6–14.5 N). The sensory studies indicated that 10% BVP incorporated doughnut was highly acceptable with higher dietary fibre content. The higher retention of betacyanin (17.88 mg 100 g⁻¹), betaxanthin (12.9 mg 100 g⁻¹), betanin (6.61 mg 100 g⁻¹), TPC (25.74 mg GAE 100 g⁻¹), TFC (77.08 mg QE 100 g⁻¹) and TAC (28.76 mMTE 100 g⁻¹) was observed.