Identification of NARMAX Hammerstein models with performance assessment using brain storm optimization algorithm

In this paper, brain storm optimization (BSO)‐based efficient identification approach has been applied to different types of stable and practically useful Nonlinear Auto Regressive Moving Average with exogenous noise (NARMAX) Hammerstein models with various performance criteria‐based assessments. Different performance measures of the estimation process like accuracy, precision and consistency have been established to ensure the general applicability and practical usefulness of the proposed approach. The accuracy and the precision of the parameter estimation are established with the corresponding bias and variance information, while the consistency has been justified with the help of hypothesis test results. BSO‐based optimum values of the output mean square errors and the parameters and their corresponding convergences ensure the stability and robustness of the proposed identification scheme. The comparative studies of the performance of the BSO algorithm with the other basic evolutionary algorithms have been reported with optimum values of the mean square errors, estimated values of the parameters, corresponding computational times and hypothesis test outcomes. Copyright © 2016 John Wiley & Sons, Ltd.     

An Authentication Technique for Image/Legal Document (ATILD)

The paper presents an image/legal-document authentication and secures message transmission technique by embedding message/image/message-digest into color images. Image authentication is done by embedding message/image within the image pixels of source image. Legal document authentication is done by embedding the authenticating image and self generated message digest (generated from signed document part) into the image part of the legal document. The position of insertion is chosen within each byte of source image using XOR operation between upper three bits of each source byte and k where k is any number from 0 to 7. Three bits of authenticating message/image/message-digest are embedded in each byte of source image. Fabrication process starts with the dimension of authenticating image followed by message digest (MD) and ends by embedding the content of authenticating message/image. To enhance the security further a layer has also been fabricated by XOR operation of the embedded image with another self generated MD key obtained from the source image. The decoding is done by applying the reverse algorithm. Experimental results are tested with the aid of Histogram analysis, noise analysis, standard deviation computation and PSNR, IF, MSE analysis of the source and embedded image and has been compared with popular existing steganographic algorithms like S-Tools where the proposed ATILD is capable to hide large volume of data than S-Tools and shows better performance. The proposed ATILD technique also shows high amount of sustainability against various attacks.     

Removal of FeCl3 from aqueous solution by ultrafiltration using ordered mesoporous MCM-48 ceramic composite membrane

Mesoporous MCM-48 membrane was prepared on a low-cost circular-shaped ceramic support by a hydrothermal crystallization technique. The characteristics of MCM-48 powder and composite membrane were evaluated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), porosity and water permeation test. The porosity and pore size of the composite membrane were found to be 22% and 0.142 µm, respectively. The MCM-48 composite membrane was investigated for the separation potential of FeCl₃ from aqueous solution and a maximum rejection of 86% was obtained for a feed concentration of 250 ppm at lower pH 2.     

An Analysis of Pressure Drop and Holdup for Liquid‐Liquid Upflow through Vertical Pipes

The present study has attempted to investigate pressure drop and holdup during simultaneous flow of two liquids through a vertical pipe. The liquids selected were kerosene and water. The measurements were made for phase velocities varying from 0.05–1.2 m/s for both liquids. The pressure drop was measured with a differential pressure transducer while the quick closing valve (QCV) technique was adopted for the measurement of liquid holdup. The measured holdup and pressure drop were analyzed with suitable theoretical models according to the existing flow patterns. The analysis reveals that the homogeneous model is suitable for dispersed bubbly flow whereas bubbly and churn‐turbulent flow pattern is better predicted by the drift flux model. On the other hand, the two fluid flow model accurately predicts the pressure drop in core annular flow.     

A facile synthesis of MInSe<Subscript>2</Subscript> (M = Cu,Ag) via low temperature pyrolysis of single source molecular precursors, [(R<Subscript>3</Subscript>P)<Subscript>2</Subscript>MIn(SeCOAr)<Subscript>4</Subscript>]

The reaction of KSeCOAr with InCl₃ and [MCl(PR₃)₂] in benzene afforded bimetallic complexes, [(R₃P)₂MIn(SeCOAr)₄] (PR₃ = PEt₃ or PPh₃; M = Cu or Ag; Ar = −C₆H₅ (phenyl) or 4-MeC₆H₄ (tolyl)). The triethylphosphine complexes decomposed rapidly when M = Ag while slowly when M = Cu. All these complexes were characterized by elemental analysis, IR, UV-VIS, NMR (¹H, ³¹P) spectral data. Pyrolysis in a furnace at 300°C gave tetragonal MInSe₂ (M = Cu, Ag) structure. Solvothermal decomposition of [(PPh₃)₂CuIn(SeCOAr)₄] in boiling ethylene glycol gave nanorods of CuInSe₂ which were characterized by XRD, EDAX, SEM and TEM.     

Al-MCM-41 catalyzed decomposition of polypropylene and hybrid genetic algorithm for kinetics analysis

Mesoporous catalysts (Al-MCM-41) are synthesized by sol–gel and hydrothermal methods to study their effects on the catalytic decomposition of polypropylene (PP) sample. The catalysts are characterized by X-ray diffraction (XRD) analysis and nitrogen adsorption study. Since sol–gel Al-MCM-41 catalyst shows better catalytic activity, further experimental studies were conducted to find its reusability and its activity at five different heating rates. The constant pattern behaviour of the TG curves for different catalyst percentages possibly suggests existence of similar reaction mechanism where large polymer fragments are cracked on the external surface of the catalyst and then enters into the mesopores for further cracking. Thus, presence of catalyst surfaces not only converts the polymer into comparatively smaller fractions, but also makes the decomposition of PP energy effective. Kinetics parameters are estimated based on 15 different decomposition models and the multi-heating rate experimental data both for catalytic and noncatalytic decomposition of PP using hybrid genetic algorithm (HGA). Suitability of the model is tested using corrected Akaike's Information Criteria (AIC_c). Results show that Nucleation and Growth model better predicted the experimental TGA data. However, nth order model also shows good AIC_c score and well predicted the experimental TGA data. Thus, though apparently it seems that Nucleation and Growth model controls the decomposition of PP sample, further investigation in detail including infrared or mass spectroscopy, morphology study using SEM or TEM during such decomposition is very much essential to conclude upon the actual reaction mechanism that controls decomposition of PP sample.     

Efficient Switched Thermoelectric Refrigerators for Cold Storage Applications

We present switching methods that make thermoelectric refrigerators efficient and optimal for all cold storage applications. These temporal methods double the coefficient of performance (COPs) of the refrigerators during cooling transients and allow highly energy-efficient operation in the steady state by turning off the thermoelectric devices both electrically and thermally so as to avoid back-conduction of heat through the devices. We describe thermoelectric refrigerator cooling engines that attain these enhancements without using any unreliable mechanically moving switching components such as pumps. These switching techniques can provide a fivefold reduction in energy consumption of cold storage refrigerators.     

Interaction Characteristics and Thermodynamic Behaviour of Gatifloxacin by Aluminium Hydroxide

ABSTRACT

The interaction pattern of gatifloxacin was temperature-dependent Langmuir isotherm, and the Langmuir coefficients increased as the temperature was raised. The perturbation experiment conducted on this system showed that the nature of interaction was irreversible. The enthalpy change is a positive value, indicating the existence of increased activation energy as the temperature is raised. The entropy value, 24.21 e.u. obtained in this system, indicated that the hydration shells of the ions were rather tightly bound. Intestinal permeation study also revealed the decreased bioavailability of gatifloxacin relatively to the presence of aluminium hydroxide. The strong adsorption of gatifloxacin by aluminium hydroxide is due to formation of complexes with cations of aluminium hydroxide through carboxyl and carbonyl groups of gatifloxacin.     

Experimental determination of refractive index of condensed reflectin in squid iridocytes

Loliginid squid dynamically tune the structural iridescence of cells in their skin for active camouflage and communication. Bragg reflectors in these cells consist of membrane-bound lamellae periodically alternating with low refractive index extracellular spaces; neuronal signalling induces condensation of the reflectin proteins that fill the lamellae, consequently triggering the expulsion of water. This causes an increase in refractive index within the lamellae, activating reflectance, with the change in lamellar thickness and spacing progressively shifting the wavelength of reflected light. We used micro-spectrophotometry to measure the functionally relevant refractive index of the high-index lamellae of the Bragg reflectors containing the condensed reflectins in chemically fixed dermal iridocytes of the squid, Doryteuthis opalescens. Our high-magnification imaging spectrometer allowed us to obtain normalized spectra of optically distinct sections of the individual, subcellular, multi-layer Bragg stacks. Replacement of the extracellular fluid with liquids of increasing refractive index allowed us to measure the reflectivity of the Bragg stacks as it decreased progressively to 0 when the refractive index of the extracellular medium exactly matched that of the reflectin-filled lamellae, thus allowing us to directly measure the refractive index of the reflectin-filled lamellae as n_{condensed lamellae} ≈ 1.44. The measured value of the physiologically relevant n_{condensed lamellae} from these bright iridocytes falls within the range of values that we recently determined by an independent optical method and is significantly lower than values previously reported for dehydrated and air-dried reflectin films. We propose that this directly measured value for the refractive index of the squid''s Bragg lamellae containing the condensed reflectins is most appropriate for calculations of reflectivity in similar reflectin-based high-index layers in other molluscs.