Feature extraction using median–mean and feature line embedding

In this article, we propose a feature extraction method based on median–mean and feature line embedding (MMFLE) for the classification of hyperspectral images. In MMFLE, we maximize the class separability using discriminant analysis. Moreover, we remove the negative effect of outliers on the class mean using the median–mean line (MML) measurement and virtually enlarge the training set using the feature line (FL) distance metric. The experimental results on Indian Pines and University of Pavia data sets show the better performance of MMFLE compared to nearest feature line embedding (NFLE), median–mean line discriminant analysis (MMLDA), and some other feature extraction approaches in terms of classification accuracy using a small training set.     

The TiO2–Clay-LDPE Nanocomposite Packaging Films: Investigation on the Structure and Physicomechanical Properties

The role of nanoclays and TiO₂ nanoparticle loadings were investigated on low density polyethylene crystalline structure, in addition to studying packaging film properties such as barrier, thermal and mechanical properties. The polymer crystal study indicated for the orthorhombic crystal phase and about 20% lower degree of crystallinity for nanocomposites containing more than 2 wt.% TiO₂ nanoparticles. Based on the X-ray diffraction technique, the dispersion of nanoclays was improved to almost good degree of clay exfoliation with the company of 4 wt.% TiO₂ nanoparticles. In agreement with XRD results, the TEM morphological studies mainly suggest that TiO₂ has a helpful effect on nanoclay exfoliation. The increase in degradation temperature of nanocomposites may be attributed to the formation of inorganic char on polymer melt. The barrier properties of TiO₂/clay nanocomposite packaging films depend mainly on nanoclay loading with an unclear trend from TiO₂ nanoparticles. The increase in elastic modulus and the yield stress of nanocomposite films showed great effects on film mechanical properties by nanoclays.     

Using computer simulation techniques to design a tellurium-123 target for <Superscript>123</Superscript>I production

The production of ¹²³I from ¹²³Te by the ^l23Te(p, n)¹²³I reaction at various target enrichments (99.9, 91, 85.4, and 70.1%) was simulated using ALICE and SRIM programs. The ¹²³I production feasibility by the above reaction was evaluated. The calculations give more accurate results for proton beam energy of less than 30 MeV. The cross sections of all tellurium reactions with proton were calculated at 0–30 MeV proton beam energy with ALICE program, and the yield of ¹²³I was calculated by analytical methods. Our prediction for ¹²³I production via bombardment of ¹²³Te (99.9%) with a proton beam energy of 5–15 MeV is about 7.2 mCi μA⁻¹ h⁻¹. Published in Russian in Radiokhimiya, 2008, Vol. 50, No. 5, pp. 460–463. The text was submitted by the authors in English.     

Miscibility study of chitosan/polyethylene glycol fumarate blends in dilute solutions

Solution miscibility of chitosan/polyethylene glycol fumarate blends dissolved in acetate buffer solution was investigated in different blend compositions by viscosity, density, and refractive index measurement techniques at 30, 40, and 50°C. In order to quantify the miscibility of the polymer pair, degree of miscibility was studied by means of two criteria known as interaction parameters i.e., μ and α. On the basis of the sign convention involved in these criteria, these values revealed that the blend solution was miscible when the chitosan content was more than 80% (w/w) of the composition. The results were confirmed by density, and refractive index measurements. Furthermore, the results showed that the miscibility window of chitosan/polyethylene glycol fumarate blends was independent with respect to the changes in solution temperature. Therefore, these results suggested due to intermolecular hydrogen‐bonding interaction between amino and hydroxy groups of chitosan and hydroxy groups of polyethylene glycol fumarate which play an important role in the formation of miscible phase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Axial mixing and mass transfer investigation in a pulsed packed liquid–liquid extraction column using plug flow and axial dispersion models

In this research work, the volumetric overall mass transfer coefficient based on continuous-phase (K_oca) and axial dispersion coefficients of phases (E_c, E_d) in a pilot Pulsed Packed Liquid Extraction Column (PPLEC) have been studied using plug flow model (PFM) and axial dispersion model (ADM). Experiments have been carried out using standard systems of water/acetone/toluene and water/acetone/n-butyl–acetate. Values of K_oca evaluated by ADM are greater than those of PFM by about 20% indicating that the axial mixing lowers the performance of PPLEC. It was found that the drop-size distribution is the main cause of the axial mixing in PPLEC. Increase in dispersed phase flow rate (Q_d), increases all K_oca, E_d and E_c and the minimum values of both E_d and E_c and the maximum values of K_oca are in pulse intensity ranges of 0.8–1 cm/s. Finally, three empirical correlations are proposed for the prediction of these parameters which are in good agreement with the experimental data.     

Effect of methyl methacrylate content on coatings’ properties of palm oleic acid-based macromer

The macromer was synthesized using medium oil length oleic acid, phthalic anhydride, and glycerol. The synthesized macromer and methyl methacrylate (MMA) were copolymerized by free radical polymerization in toluene. The ratio between the macromer and MMA changed, and the effects on different properties of the copolymers, such as glass transition temperature (T _g) and film properties, were studied. The macromer and copolymer structures were characterized by FTIR and ¹H NMR spectroscopies. The coatings prepared with the highest ratio of MMA exhibited better overall physico-chemical properties. Alternatively, Tafel polarization curves showed that the corrosion rate value in NaCl solution decreases significantly when the MMA content is increased. Dynamic mechanical analysis results revealed that the increasing amounts of MMA lead to increasing T _g values of copolymers.     

Degradation of histamine solutions used for bronchoprovocation

STUDY OBJECTIVES: To determine optimal storage conditions for histamine diphosphate (HDP) solutions used for bronchoprovocation. DESIGN: HDP was dissolved in buffered saline solution to concentrations of 0.125 to 16 mg/mL and stored in 3-mL unit dose syringes at different temperatures for varying lengths of time, with and without protection from fluorescent light. SETTING: Dark freezer (-20 degrees C), dark refrigerator (4 degrees C), and laboratory counter top (20 degrees C) illuminated by fluorescent light (375 foot-candles). MEASUREMENTS: HDP concentrations were measured after the solutions were prepared and during storage by a high-performance liquid chromatographic assay that differentiates histamine from its break down products. RESULTS: All dilutions were sterile after preparation and contained 97 to 110% of the labeled amount of HDP. Solutions constantly exposed to fluorescent light (375 foot-candles) and room temperature (20 degrees C) contained only 20 to 37% of the initial concentrations after 7 days. The same dilutions stored at room temperature, but protected from light, contained 83 to 94% of the initial concentrations. Dilutions stored in the dark in a refrigerator (4 degrees C) retained 97% of the initial concentrations after 8 weeks, while dilutions stored in the dark freezer (-20 degrees C) were stable for 12 months. CONCLUSIONS: Exposure to fluorescent light at room temperature results in degradation of histamine solutions used for bronchoprovocation. Dilutions stored in unit dose syringes and protected from light are stable for at least 8 weeks in the refrigerator and up to 12 months frozen. Once removed from the refrigerator or freezer, the solutions should be used within 6 h or discarded.     

A new time-delay estimation in multipath

This paper addresses a new approach to time-delay estimation based upon the autocorrelation estimator (AE). The primary aim of this paper is to estimate time-delays in a multipath environment in absence of prior knowledge of the channel. The maximum likelihood estimator (MLE) and AE are two computational tools that are used to determine the parameters of a multipath channel. MLE requires some priori knowledge of the source signal and the channel; AE can be a blind estimator but it is more suitable for a simple propagation model (one extra path). Under the multipath assumption we prove that if the observation sequence is zero padded the performance of MLE exceeds that of AE, however, at the price of higher computational efforts. The general autocorrelator estimator (GAE), based on autocorrelation of the received signal, is introduced. The GAE is formulated as a blind estimator, and the pertinent Cramer-Rao lower bounds (CRLB) are derived. We also develop an algorithm to estimate the parameters of a multipath environment based on the new generalization. The performance of this algorithm is examined for different signal-noise scenarios. Our results show that the time-delays are estimated accurately based on the proposed algorithm.     

Nonlinear two-dimensional velocity profile inversion using timedomain data

An iterative algorithm is developed to solve the nonlinear inverse scattering problem for two-dimensional lossless dielectric inhomogeneities using time-domain scattering data. The method is based on performing Born-type iterations on a volume integral equation and, hence, successively calculating higher-order approximations to the unknown object profile. Both the full-angle and the limited-angle problems are considered. Solutions are obtained for cases where the first-order Born approximation is severely violated. Wideband time-domain scattered field measurements make it possible to use sparse data sets and thus reduce experimental complexity and computation time. Several examples are given to show the ability of this method to invert arbitrarily shaped permittivity profiles using few transmitters and receivers. The high-resolution capability of the algorithm is also demonstrated