ESTIMATION OF ACTIVITY COEFFICIENTS AT INFINITE DILUTION OF HALOCARBONS IN WATER AND ORGANIC COMPOUNDS IN HYDROFLUOROPARAFFINS USING NEURAL NETWORKS

Infinite dilution activity coeffcents ( 1) of 19 halocarbons in water and 18 organic compounds in 5 hydrofluoroparaffins over a temperature range of 291 333K have been estimated by the method of neural nets. The network was trained using 351 data points covering 18 halocarbons in water and 17 organic compounds in 4 hydrofluoroparaffins, and generalization test was carried out using the remaining 92 data points covering one halocarbon in water, 17 organic compounds in a hydrofluroparaffin, and an organic compound in 5 hydrofluoroparaffins. Seven inputs are included in the network, namely the temperature, dipole moment, molar refraction and critical pressure of the solute and solvent. The network represented the data with an overall average absolute deviation of 11.8% estimated on the basis of the values of 1. The result obtained could be considered reasonable in view of the wide variations in the values of the input properties and 1 values and the varied nature and size of compounds treated. Among the several variables studied, dipole moment contributed to the correlation the most, followed by the critical pressure. Further study on the applicability of MLR (multilinear regression) method revealed the overwhelming superiority of the neural network over MLR.     

Effects of (conductive polypyrrole)‐modified tire dust on the mechanical,electrical, and morphology properties of (low‐density polyethylene)/(tire dust) composites

The effects of conductive polypyrrole (PPy) as a coupling agent on the mechanical properties, morphology, electrical properties, and thermal degradation of (low‐density polyethylene)/(tire dust) (LDPE/TD) composites were studied. LDPE/TD composites with different TD loadings and added PPy were prepared with a Brabender Plasticorder. The LDPE/TD_T (treated with PPy) composites showed higher values of tensile strength, modulus of elasticity, electrical conductivity, thermal stability, and swelling resistance than LDPE/TD composites. Scanning electron microscopy morphology revealed that the interfacial adhesion between the TD and LDPE phases was improved by the addition of conductive PPy. J. VINYL ADDIT. TECHNOL., 20:131–136, 2014. © 2014 Society of Plastics Engineers     

Mode shapes and frequencies of radially symmetric vibrations of annular sandwich plates of variable thickness

An analysis and numerical results of radially symmetric vibrations of annular sandwich plates with core of linearly varying thickness are presented. The face sheets are treated as membranes of constant thickness, and the core is assumed to be solid as well as moderately thick. Due to linear thickness variation in the core, the face sheets take the shape of a truncated conical shell and because of this the face sheets membrane forces contribute to the bending and transverse shear of the core of the sandwich plate. Keeping this in view, the equations of motion for such a plate are developed by Hamilton’s energy principle. The frequency equations for three different combinations of boundary conditions, namely clamped at the inner edge and clamped or simply supported or free at the outer edge, are obtained by employing the differential quadrature method. The lowest three roots of these frequency equations have been reported as the frequencies for the first three modes of vibration. The effect of various plate parameters such as taper parameter, thickness of the core at the center, face thickness, and radii ratio on the natural frequencies has been analyzed. Three-dimensional mode shapes for a specified plate for all the three boundary conditions are illustrated. A comparison of results is presented.     

Two level security for medical images using watermarking/encryption algorithms

In this article, an attempt is made to provide two level securities for medical images using watermarking and encryption. Watermarking provides security and encryption, authenticates medical image and provides integrity. Watermarking is performed by using a new nontensor product wavelet filter banks, which have the ability to reveal singularities in different directions. Natural image is taken as the original image and the medical image is taken as a watermark image. The medical image is embedded into the LH sub band of the natural image. The encryption is performed by RSA, AES, and RC4 algorithms. A qualitative comparative analysis of the proposed algorithm is done for different encryption methods. The proposed algorithm has the ability to withstand different attacks like noise, rotation, contrast, and brightness attacks. Performance analysis is made by calculating PSNR, SSIM, NC, and CV.     

Solubility of Mn stabilized cubic zirconia nanostructures

Mn-stabilized cubic zirconia nanostructures (Zr_1?xMn_xO₂, x = 0.10, x = 0.15 and x = 0.20) have been prepared using chemical precipitation method for different doping concentrations. The prepared powders have been characterized by X-ray diffractometer for structural analysis, vibrating sample magnetometer for analyzing magnetic properties, scanning electron microcopy–elemental compositional analysis using X-ray for morphological and elemental compositional analysis. Room temperature ferromagnetism has been found at around x = 0.15. For high doping effect of Mn impurity at host lattice, secondary phase has been detected at around x = 0.20 when exceeding the solubility limit of cubic zirconia. Due to ferromagnetic behavior, Mn doped ZrO₂ nanostructures can be considered as good candidates for spintronics applications within their solubility limit.     

Studies on natural rubber bound para-phenylenediamine antioxidants in NBR

Para-phenylenediamine (PD) was chemically attached to depolymerized natural rubber by a photochemical reaction. The rubber bound PD was characterized by TLC, ¹H-NMR, IR, and TGA. The efficiency and permanence of the bound PD were compared with conventional antioxidants in NBR vulcanizates. The rubber bound PD was found to be less volatile and more resistant to water and oil extraction. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing conventional antioxidants. The liquid rubber bound antioxidant reduces the amount of plasticizer required for compounding. © 1995 John Wiley & Sons, Inc.     

Acid-base,electron-donating and magnetic properties of Nd2O3 and its mixed oxides with alumina catalysts

The electron donor properties of Nd₂O₃ activated at 300, 500 and 800°C were investigated through studies on the adsorption of electron acceptors of various electron affinities — 7, 7, 8, 8-tetracyanoquinodimethane (2.84 eV), 2, 3, 5, 6-tetrachloro-1, 4-benzoquinone (2.40 eV), p-dinitrobenzene (1.77 eV), and m-dinitrobenzene (1.26 eV) in solvents acetonitrile and 1, 4-dioxan. The extent of electron transfer during adsorption has been found from magnetic measurements and electronic spectral data. The corresponding data on mixed oxides of neodymium and aluminium are reported for various compositions. The acid-base properties of catalysts were also determined using a set of Hammett indicators.     

Fixed-width confidence interval estimation of the inverse coefficient of variation in a normal population

A sequential procedure is developed in order to construct a confidence interval of “fixed-width and preassigned coverage probability” for the inverse of the coefficient of variation of a normal population. The proposed sequential procedure is proved to be “asymptotically efficient and consistent” in the sense of Chow and Robbins ([1]: Ann. Math. Statist. 36, 457–462 (1965)). Asymptotic distribution of the stopping time is derived.     

The yields of extracted leaf protein from lucerne (Medicago sativa L.)

The effects of fertilisers, frequency of cutting, row spacing and simazine on the yields of dry matter and extractable protein from lucerne (Medicago sativa L.) were studied using the laboratory-scale pulper and press. Between 40 and 65% protein nitrogen was extractable; extractability was not affected by the various treatments but altered with season. Lucerne responded with increased yields of dry matter and extractable protein to fertilisers, simazine (35 g/ha) and rows spaced at 30.5 cm. Six or 8 harvests were found to give greater yields than 5 harvests in 180 days. The annual yields of extractable protein reached 3100 kg/ha and it is felt that better control of pests could lead to even greater yields.     

Modulation of cell growth and apoptosis response in human prostate cancer cells supplemented with tocotrienols

Previous studies have shown that tocotrienols are powerful growth inhibitors and potent inducers of apoptosis in human breast cancer cells. The objective of the current study was to examine effects of tocotrienols on apoptotic signals in androgen‐independent PC‐3 human prostate cancer cells. We investigated the effects of the tocotrienol‐rich fraction (TRF) from palm oil, α‐tocopherol (αT), α‐tocotrienol (αT₃), γ‐tocotrienol (γT₃) and δ‐tocotrienol (δT₃) on PC‐3 cell growth. TRF inhibited PC‐3 growth with a nonlinear response, with complete growth suppression at 10 µg/mL. δT₃ and γT₃ showed complete cell inhibition at 8 µg/mL whilst αT had no effect. δT₃ and γT₃ showed the most promise in the cell growth assays, and all subsequent experiments were performed with δT₃, TRF and αT. TRF and δT₃ at 8 µg/mL induced apoptosis in PC‐3 cells after 48 h of treatment. In addition, TRF and δT₃ treatments were able to affect the cell cycle, with accumulation in the S phase, G2 phase block and increases in SubG1 by 72 h. We then proceeded to investigate the expression levels of Fas receptor and Fas ligand, caspase 8, caspase 3 and bax in PC‐3 cells following treatment with tocotrienols using real‐time PCR and Western blot methods. TRF and δT₃ at 8 µg/mL increased Fas ligand expression levels by 368 and 456%, respectively, after 24 h and Fas receptor expression levels by 210% and 356%, respectively, after 48 h. TRF‐ and δT₃‐treated PC‐3 cells overexpressed caspase 8 and bax protein after 24 h, and caspase 3 after 48 h. In conclusion, tocotrienols are able to induce apoptosis and cell cycle arrest in PC‐3 cells, with increased expression of Fas receptor, Fas ligand, caspase 8, caspase 3 and bax, suggesting a potential role in chemoprevention of prostate cancer.