Definitions of the degree of polarization of a light beam

A necessary and sufficient condition is derived for certain ad hoc expressions that are frequently used in the literature to represent correctly the degree of polarization of a light beam.     

Nematicons in liquid crystals by modified simple equation method

Nonlinear Dynamics - This paper obtains nematicon solutions in liquid crystals by the aid of modified simple equation method. There are four types of nonlinearity studied. They are cubic law, power...     

Synthesis of New Highly Functionalized 1H-Indole-2-carbonitriles via Cross-Coupling Reactions

An approach for the preparation of polysubstituted indole-2-carbonitriles through a cross-coupling reaction of compounds 1-(but-2-ynyl)-1H-indole-2-carbonitriles and 1-benzyl-3-iodo-1H-indole-2-carbonitriles is described. The reactivity of indole derivatives with iodine at position 3 was studied using cross-coupling reactions. The Sonogashira, Suzuki–Miyaura, Stille and Heck cross-couplings afforded a variety of di-, tri- and tetra-substituted indole-2-carbonitriles.     

Influence of Salinity Stress on Color Parameters,Leaf Pigmentation,Polyphenol and Flavonoid Contents,and Antioxidant Activity of Amaranthus lividus Leafy Vegetables

This is the first attempt to evaluate the impact of four salinity levels on the color parameters, pigments, polyphenols, flavonoids, and antioxidant capacities of four promising A. lividus genotypes. The color parameters, such as the yellowness/blueness (b*) and the chroma (C*); the antioxidant components, such as the polyphenols and flavonoids; and the antioxidant capacities of the leaves were remarkably increased by 39, 1, 5, 10 and 43%, respectively, at 50 mM of NaCl, and by 55, 5, 60, 34, 58 and 82%, respectively, at 100 mM NaCl concentrations. The green tower and SA6 genotypes were identified as tolerant varieties. The total phenolic content (TPC) and the total flavonoid content (TFC) played vital roles in scavenging reactive oxygen species (ROS), and they would be beneficial for the human diet and would serve as good antioxidants for the prevention of aging, and they are also essential to human health. A correlation study revealed the strong antioxidant capacities of the pigments and antioxidant components that were studied. It was revealed that A. lividus could tolerate a certain level of salinity stress without compromising the antioxidant quality of the final product. Taken together, our results suggest that A. lividus could be a promising alternative crop for farmers, especially in saline-prone areas in the tropical and subtropical regions.     

Investigation of photocatalytic chlorpyrifos degradation by a new silica mesoporous material immobilized by WS2 and Fe3O4 nanoparticles: Application of response surface methodology

In the present research, Fe₃O₄ and WS₂ nanoparticles immobilized on or in KIT-6 (KIT: Korea Institute of Science and Technology) pores (KIT-6/WS₂-Fe₃O₄) were synthesized and studied as a photocatalyst for degradation of representative chlorpyrifos as an organophosphorus pesticide. In addition, the KIT-6/WS₂-Fe₃O₄ photocatalyst was characterized by different methods such as TEM, FESEM-EDS-Mapping, XRD, and N₂ adsorption/desorption surface area, in order to understand their morphology, structural, and physical properties. The photocatalytic performance of this photocatalyst was investigated for degradation of chlorpyrifos by visible light irritation. The effects of variables such as chlorpyrifos concentration, KIT-6/WS₂-Fe₃O₄ nanocatalyst amount, pH, and irradiation time on chlorpyrifos degradation efficiency was studied by central composite design with response surface methodology. The optimum conditions for CP degradation were obtained by 50 mg KIT-6/WS₂-Fe₃O₄ nanocatalyst, and 7.2 ppm chlorpyrifos solution with pH = 6, at 52 min. The pseudo-first-order model with rate constants equal to 0.069 min⁻¹ as best choice efficiency described the chlorpyrifos degradation process according to Langmuir-Hinshelwood kinetic.     

Application of classification methods to analyze chemicals in drinking water quality

Accreditation and Quality Assurance - To analyze drinking water dataset, various statistical methods have been applied, including discriminant analysis, logistic regression and cluster analysis, to...     

Resolution of multicomponent mixture of amino acids using environmentally benign eluents: A green chromatographic approach

A new green TLC has been used for identifying and monitoring the migration behavior of amino acids through silica and kieselguhr static flat bed in contact of n-butyl alcohol, ethyl acetate or ethylene glycol and their mixtures. From the point of view of chromatographic performance, a mixture of n-butyl alcohol-70% aqueous ethylene glycol-ethyl acetate ratio 5:3:2 by volume proves to be more efficient than the individual components for separation of amino acids from their binary, ternary and quaternary mixtures and the chromatographic parameters like ΔR(F) , separation factor (α) and resolution (R(S) ) for the separation were calculated. Effect of the presence of foreign substances such as metal cations, anions, vitamins and pesticides as impurities in the sample on the separation was also examined. Effect of substitution of butanol by various alcohols has been examined to assess the impact of hydrophobicity of alcohols on the separation of amino acids. The limits of detection for tyrosine, tryptophan, alanine, isoleucine, methionine and serine were found to be 0.10?μg/spot, whereas for lysine it is 0.05?μg/spot. Application of the selected TLC system for the identification and separation of amino acids present in drugs/pharmaceuticals has been performed.     

Eco-friendly and cleaner process for isolation of essential oil using microwave energy: Experimental and theoretical study

Microwave steam diffusion (MSD) was developed as a cleaner and new process design and operation for isolation of essentials oils and was compared to conventional steam diffusion (SD). The essential oils extracted by MSD for 3 min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional steam diffusion for 20 min. In addition, an optimal operating steam flow rate of 25 g min⁻¹ and microwave power 200 W were found to ensure complete extraction yield with reduced extraction time. To confirm the efficiency of this process a mathematical model was proposed to describe the mass transfer of essential oil from lavender. Solid-steam mass transfer coefficients obtained by MSD were six times higher than obtained by SD. Scanning electronic microscopy was used to confirm the extraction mechanism of the essential oil present in the glandular trichomes of the flowers from lavender outer surface. MSD was better than SD in terms of energy saving, cleanliness and reduced waste water.     

On Linear Preservers of Two-Sided Gut-Majorization On <Emphasis Type="Bold">M</Emphasis><Subscript><Emphasis Type="Italic">n</Emphasis>,<Emphasis Type="Italic">m</Emphasis></Subscript>

For X, Y ∈ M_n,m it is said that X is gut-majorized by Y, and we write X ?_gutY, if there exists an n-by-n upper triangular g-row stochastic matrix R such that X = RY. Define the relation ~_gut as follows. X ~_gutY if X is gut-majorized by Y and Y is gut-majorized by X. The (strong) linear preservers of ?_gut on ?ⁿ and strong linear preservers of this relation on M_n,m have been characterized before. This paper characterizes all (strong) linear preservers and strong linear preservers of ~_gut on ?ⁿ and M_n,m.