An image encryption method based on chaos system and AES algorithm

The Journal of Supercomputing - In this paper, a novel image encryption algorithm is proposed based on the combination of the chaos sequence and the modified AES algorithm. In this method, the...     

Mass Transfer Studies in Stirred AirLift Reactor

In the present work, water and three phase compositions of Solka-Floc, a cellulose fiber for simulating the biomass in bacteria, yeast, and fungal fermentation were studied in a 1.4 m³ stirred airlift reactor. The fractional dispersed phase holdup and the overall volumetric mass transfer coefficients were measured. The dispersed phase riser gas holdup and overall volumetric mass transfer coefficients both increased with increasing riser superficial dispersed phase velocity (0.02-0.1 ms^-1) and agitator speed in the range of 0-5 rs^-1. An increase in the Solka-Floc concentration (1-3% w/v) was found to reduce ε_GR and K_La_L. Empirical correlations have been developed for fractional dispersed phase gas holdup and overall volumetric mass transfer coefficients.     

Effect of nano layered silicates on automotive polyurethane refinish clear coat

In the present investigation, effect of nano layered silicates on the properties of an automotive refinish clear coat based on polyurethane has been studied. Observation by means of X-ray diffraction (XRD) technique indicates the presence of a partially intercalated structure due to dispersion of nano layers in the polymer matrix. Some levels of hazing have been established by increasing the amount of nano-filler. The effect of nano-filled clear coat on the reflectance spectra of a metallic coated substrate has been studied under three different light sources using a goniospectrophotometer and compared with a blank clear coat to determine if it can be identified by human eye. Scratch and mar resistance tests showed significant improvement even 48 h after application, when there was no gloss reduction due to usage of nano-filler. Gloss retention was increased by about 10% in presence of only 3 wt% of nano-filler. In addition to some scratch and mar resistance tests, other standard tests like adhesion, impact and bending were performed to find out optimum nano-filler/polymer ratio.     

Synthesis and properties of novel flame‐retardant poly(amide‐imide)s containing phosphine oxide moieties in main chain by microwave irradiation

Eight new flame‐retardant poly(amide‐imide)s with high inherent viscosities containing phosphine oxide moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7, with eight ;aromatic diamine 8a–h by two different methods such as solution and microwave‐assisted polycondensation. Results showed that the microwave‐assisted polycondensation by using a domestic microwave oven proceeded rapidly, compared with solution polycondensation and were completed within about 10–12 min. The resulting poly(amide‐imide)s 9a–h showed high thermal stability and flame‐retardant properties. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties of the PAIs 9a–h were investigated by using thermal gravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Char yield measurements at 600°C demonstrated that incorporating phosphine oxide moieties in polymer backbone markedly improves their flame retardancy. All of the earlier polymers were soluble at room temperature in various organic solvents such as NMP, DMF, DMSO, DMAc, and concentrated sulfuric acid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4263–4269, 2006     

Implementation of Kalman Filter on PSoC-5 Microcontroller for Mobile Robot Localization

Robots facilitate exploration of hazardous environments during response to catastrophe. Autonomous robotic platforms involved in search and rescue operations require accurate position and orientation （localization） information for self-navigation from its current position to its subsequent destination. A Hybrid Routing Algorithm Model has been proposed by the SPACE （structures, pointing and control engineering） URC （university research center） at California State University of Los Angeles. This model envisions three-layered terrain mapping with obstacle representations from various information sources such as satellites, UAVs and onboard range sensors. A＊ path-finding algorithm is applied to the outer two layers of the model （Layer 1 and Layer 2）, while dynamic A＊ algorithm is responsible for innermost layer （Layer 3） navigation. The mobile robot localization information is computed using data obtained from a 9 Degrees of Freedom Inertial Measurement Unit. While gyroscope sensors provide the system the instantaneous radial velocity of a turning platform, these sensors are also susceptible to drift. Accelerometers are extremely sensitive to vibrations, and along with fluctuating magnetic fields, both accelerometers and magnetometers exhibit noisy behaviors when localizing the robot. Since the IMU contains all three sensors, a Kalman Filter is implemented on a PSoC-5 microcontroller to fuse data from the IMU sensors. This reduces standard deviation between measurements and improves reported heading accuracy, hence provides reliable information on the robot＇s localization and improves mapping.     

Supplier quality development: A review of literature and industry practices

Managing quality of suppliers is of prime importance in supply chains to minimise costs arising due to poor-quality products and services. Supplier quality development (SQD) is a strategic quality development activity for increasing quality, reliability and efficiency of suppliers. This paper reports results of review on the academic literature and industrial practices on SQD in order to find main concepts, steps, prevalent methodologies, tools and techniques, and best practices. We reviewed 177 papers from years 1980–2013 including 22 company manuals for conducting this study. The proposed review assists readers in developing a better understanding of SQD, involved processes and their key elements, tools and techniques used, challenges in supplier quality management, best practices from academics and industry, and open research problems in SQD that require detailed investigation.     

UWB body area network channel modeling: An analytical approach

The aim of this work is to develop an analytically-based approach for ultra wide band (UWB) body area network (BAN) channel modeling. In detail, the body will be modeled as multi-layered stratified cylinders of infinite length, and the Maxwell's equation will be solved for plane wave and line source excitations. Human-type tissues will be assumed in the multi-layered stratified cylindrical model. Validation of the procedure through measurement results has been provided.     

Wavelet-based ultra wideband pulse generator circuits

Aiming to generate ultra wideband (UWB) pulses based on wavelet packets, four different circuits are proposed. It has been shown that the wavelet packets are quasi-orthogonal and have almost identical time duration, and therefore appear to be valuable candidates for UWB pulse shape modulation systems. However, as with any technology, circuitry is an important challenge to solve before a theoretical application can live up to its full potential. The four proposed circuits are based on different interpretations of the equation defining the wavelet packets and their performance is investigated by computer simulation. The research also illustrates the characteristics and the consequent implementation advantages or issues afferent to each circuit.     

Nanometer displacement measurement using Fresnel diffraction

We introduce a relatively simple and efficient optical technique to measure nanoscale displacement based on visibility variations of the Fresnel diffraction fringes from a two-dimensional phase step. In this paper we use our technique to measure electromechanical expansions by a thin piezoelectric ceramic and also thermal changes in the diameter of a tungsten wire. Early results provide convincing evidence that sensitivity up to a few nanometers can be achieved, and our technique has the potential to be used as a nanodisplacement probe.