Effect of Thermal and High Electric Fields on Secondary Structure of Peanut Protein

This study evaluated the effect of the thermal and high electric field stresses on the secondary structure conformation of peanut protein using Fourier transform infrared spectroscopy. The amide I region between the wavelengths 1700–1600 cm^–1 of the spectra were studied for different thermal and high electric field treatments. Within thermal treatments, both hot air roasting and microwave processing treatments were evaluated. Hot air treatments were performed at temperatures of 50, 75, and 100°C from 15, 30, and 45 min while the microwave treatments were conducted at the same temperatures, but for 5, 10, 15, and 20 min. Three experimental conditions were evaluated for the electric field intensity of 10, 15, and 20 kV for 60, 120, and 180 min. Changes were observed at 1654–1650 cm^–1, indicating conformational changes in the α-helix secondary structure. Similar changes were observed at various other wavelengths indicating changes in the 3/10 helix, β-sheets and random coils present in the protein. With an increase in the treatment time, the secondary structure reorganizations increased with the creation of new random coils and aggregated strands. Curve-fitting using Gaussian band shapes further supported the observations. In vitro protein digestibility studies were also performed and the protein changes also supported the observations from the spectra.     

Experimental and numerical studies of void fraction distribution in rectangular bubble columns

Bubbly flow is encountered in a wide variety of industrial applications ranging from flows in nuclear reactors to process flows in chemical reactors. The presence of a second phase, recirculating flow, instabilities of the gas plume and turbulence, complicate the hydrodynamics of bubble column reactors.This paper describes experimental and numerical results obtained in a rectangular bubble column 0.1 m wide and 0.02 m in depth. The bubble column was operated in the dispersed bubbly flow regime with gas superficial velocities up to 0.02 m/s. Images obtained from a high speed camera were used to observe the general flow pattern and have been processed to calculate bubble velocities, bubble turbulence parameters and bubble size distributions. Gas disengagement technique was used to obtain the volume averaged gas fraction over a range of superficial gas velocities. A wire mesh sensor was applied, to measure the local volume fraction at two different height positions. Numerical calculations were performed with an Eulerian–Eulerian two-fluid model approach using the commercial code CFX.The paper details the effect of various two-fluid model interfacial momentum transfer terms on the numerical results. The inclusion of a lift force was found to be necessary to obtain a global circulation pattern and local void distribution that was consistent with the experimental measurements. The nature of the drag force formulation was found to have significant effect on the quantitative volume averaged void fraction predictions.     

A Microfluidic Chip with Integrated Colloidal Crystal for Online Optical Analysis

A microfluidic chip that incorporates colloidal crystals inside a microchannel system for on‐chip integration of optical components is presented. It is demonstrated that the use of fluorescent spheres offers added advantages and functionality to the colloidal crystal array. Multifunctional optical components are demonstrated that are able to serve as a reference wavelength calibration line in measured reflectance spectra. Integrating colloidal crystals with varying filtering effects into a microfluidic chip enables selective transmission or blocking of a particular range of wavelengths locally. In addition, combinations of double‐band colloidal crystal filters provide further tunability of the working wavelength for on‐chip detection applications.     

Electrohydrodynamic drying of sand

This study analyzes the electrohydrodynamic (EHD) drying characteristics of sand. Effect of process parameters (independent variables) including air speed, electrode gap, and applied voltage on drying kinetics and dependent variables including percentage water removed (%), Sherwood number, EHD number, and specific energy consumed (SEC) (kJ/kg) were also investigated using a central composite design and response surface methodology. Maximum drying was obtained for process parameter combination of air speed (2?m/s), electrode gap (1.5?cm), and applied voltage (15?kV). Air speed and electric field intensity (ratio of applied voltage to electrode gap) were found to have a significant effect on percentage water removed (%) and Sherwood number. In case of EHD number and SEC during the EHD drying process, all process parameters had a significant effect on them. The SEC increased with an increase in applied voltage but reduced with an increase in air speed at any given applied voltage suggesting that the EHD drying process, in combination with cross flow, will lead to higher drying rate and low energy consumption under ambient conditions. Regression models were also developed describing the relation between independent and dependent variables.     

Impact of (Pr,Dy) Co-doping at Bi Site on Optical and Multiferroic Properties of BiFeO3 Ceramics Prepared by Sonochemical Method

Semiconductors - A series of Pr and Dy were substituted at Bi of BiFeO3 were synthesized by sonochemical method. Keeping Pr at 5%, Dy composition was varied to obtain...     

A secure enhanced privacy-preserving key agreement protocol for wireless mobile networks

The rapid proliferation of mobile networks has made security an important issue, particularly for transaction oriented applications. Recently, Jo et al. presented an efficient authentication protocol for wireless mobile networks and asserted that their proposed approach provides all known security functionalities including session key (SK) security under the assumption of the widely-accepted Canetti–Krawczyk (CK) model. We reviewed Jo et al.’s proposed roaming protocol and we demonstrate that it fails to provide the SK-security under the CK-adversary setting. We then propose an enhancement to Jo et al.’s roaming protocol to address the security drawback found in Jo et al.’s protocol. In the enhanced roaming protocol, we achieve the SK-security along with reduced computation, communication and storage costs. We also simulate the enhanced roaming protocol using NS2 for end-to-end delay and network throughput, and the simulation results obtained demonstrate the efficiency of our protocol.