Extrusion of Rice,Bean and Corn Starches: Extrudate Structure and Molecular Changes in Amylose and Amylopectin

The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V^® corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V^® corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.     

Mobile Ferroelastic Domain Walls in Nanocrystalline PZT Films: the Direct Piezoelectric Effect

Ferroelastic (90°) domain wall motion occurs readily in bulk samples of displacive ferroelectrics such as Pb(Zr,Ti)O₃ (PZT), dictating critical piezoelectric, dielectric, and polarization switching properties. Many prior studies have used converse piezoelectric measurements to probe the dynamics of ferroelastic domains in thin films; however, such experiments are strongly influenced by the mechanical clamping effect of the substrate, which inhibits electric field‐induced 90° domain wall motion. Nevertheless, these observations raise a tantalizing question: Does the application of mechanical stress, rather than electric field, result in an entirely different response in thin films? Here we report biaxial stress‐driven crystallographic reorientation of (100)/(001) textured, 70 nm thick Pb(Zr_0.25Ti_0.75)O₃ films via 90° domain wall motion, measured in situ by both x‐ray diffraction and piezoforce microscopy. Visual evidence of nanoscale mechanisms that underlie the direct piezoelectric effect is shown. Mobile 90° domain walls effect complete orientation switching in the grains in which they operate, without apparent wall pinning, indicating that bulk‐like ferroelastic behavior can extend to nanocrystalline films in the absence of substrate clamping.     

Influence of fuel properties and composition on NOx emissions from biodiesel powered diesel engines: A review

Biodiesel has proved to be an environment friendly alternative fuel for diesel engine because it can alleviate regulated and unregulated exhaust emissions. However, most researchers have observed a significant increase in NO_x emissions with biodiesel when compared to petrodiesel. The exact cause of this increase is still unclear; however, researchers believe that the fuel properties have been shown to effect the emissions of NO_x. The present work reviews the effect of fuel properties and composition on NO_x emissions from biodiesel fuelled engines. The paper is organised in three sections. The first section deals with the NO_x formation mechanisms. In the following section, the reasons for increased NO_x emissions of biodiesel fuel are discussed. After this, the influence of composition and fuel properties on NO_x emissions from biodiesel fuelled engines has been reviewed. Finally, some general conclusions concerning this problem are summarised and further researches are pointed out.     

Synthesis of nanocrystalline α-Al2O3 by ultrasonic flame pyrolysis

Nanocrystalline α-alumina was synthesized in an indigenously built ultrasonic flame pyrolysis (UFP) set-up. This paper describes the technical aspects of the apparatus and particle formation in the flame. Ultrasonically atomized aluminium nitrate dissolved in methanol-water mixture was pyrolyzed in an oxy-propane flame for yielding nanocrystalline α-alumina. The formation of nanophase alumina was confirmed by powder XRD analysis. Scanning electron microscopy (SEM) analysis was carried out to study particulate morphology.     

E-Health Cloud Security Using Timing Enabled Proxy Re-Encryption

Mobile Networks and Applications - In the present era of Information Technology, almost all big and small scale companies are moving towards cloud to store and manage the data. Cloud computing is a...     

Stealthy attack detection in multi-channel multi-radio wireless networks

Multimedia Tools and Applications - In recent years, the lack of network traffic analysis and flexible network topologies reduce the performance of the multi-channel multi-radio wireless networks....     

Role of binder in the synthesis of titania membrane

The synthesis of titania membrane through sol-gel route involves hydrolysis of alkoxide peptization of hydrous oxide of titanium to obtain a sol, adjustment of the sol viscosity by including a binder and filtration of the viscous sol through a microporous support, gelation and sintering to desired temperature. The binder plays an important role in that it not only helps in adjustment of sol viscosity but also helps in binding the sol particle with porous support. Here a comparative study on the role of different binders, viz. polyvinyl alcohol, polyethyleneimine, polyacrylamide, effect of their viscosity and surface tension effect on the morphology of the titania membrane is presented. The results show that among the three binders studied polyvinyl alcohol gave rise to membranes of desired characteristics when the sol viscosity was 0.08 pa.s.     

Impact of structural changes due to heat-moisture treatment at different temperatures on the susceptibility of normal and waxy potato starches towards hydrolysis by porcine pancreatic alpha amylase

The objectives of this study were to determine the impact of structural changes within the amorphous and crystalline domains of normal potato (NP) and waxy potato (WP) starches subjected to heat-moisture treatment (HMT) at 80, 100, 120 and 130 °C for 16 h at a moisture content of 27% and to determine the impact of structural changes at each of the above temperatures on the susceptibility on hydrolysis by porcine pancreatic α-amylase (PPA). The results showed that structural changes due to HMT were influenced by differences in starch chain mobility at the different temperatures of HMT. Starch chain mobility in turn was influenced by the interplay between the extent to which B-type crystallites were transformed into A + B-type crystallites, kinetic energy imparted to starch chains and amylose content. The main type of structural changes influencing physicochemical properties at the different temperatures of HMT was starch chain interactions (at 80 and 100 °C), disruption of hydrogen bonds between amylose (AM)–amylopectin (AMP) and AMP–AMP chains (at 120 and 130 °C), disorganization of AMP chains near the vicinity of the hilum (at 100, 120 and 130 °C) and formation of interrupted helices (at 130 °C). The susceptibility of NP and WP starches towards α-amylase decreased at 80 °C, but increased in the range of 100 to 130 °C. This suggested that α-amylase hydrolysis of HMT starches was influenced by the interplay of: 1) amount of A-type crystallites, 2) starch chain interactions and 3) changes to double helical conformation. Differences in granule morphology in PPA hydrolyzed NP and WP starches were largely influenced by the higher granular swelling in the latter. NP and WP starches exhibited heterogeneity in degradation (NP > WP) in both their native and HMT states.