Efficient and Mild Synthesis of Novel Diazo Dyes through Coupling Reaction of Schiff Base Diazonium Salts with β-naphthol

In this study, efficient and mild method for synthesis of some novel diazo dyes containing Schiff bases has been reported. All of the intermediates and final products were obtained in good to high yields and appropriate reaction times. The structures of desired products were determined using physical and spectroscopy data such as; IR, ¹H NMR, ¹³C NMR, mass spectra, and C.H.N. analyses. The worldwide availability, larger scale synthesis, high yields, and short reaction times are the advantages of the present method.     

Rare earth elements distribution in marine sediments of Malaysia coasts

In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24-26 cm in EC4 increased to 114.1 μg/gr at 20-22 cm in EC5.The measured concentration of ...     

Novel nanocomposite membranes based on PBI and doped-perovskite nanoparticles as a strategy for improving PEMFC performance at high temperatures

In this work, Sr²⁺ dopant effects of Ba_0.9Sr_0.1TiO₃ and La_0.9Sr_0.1CrO_3-δ doped-perovskite nanoparticles on increasing proton conductivity, fuel cell performance, and mechanical and thermal stability of polybenzimidazole-based nanocomposite membranes were studied. The Sr²⁺ dopant creates cation vacancies in Ba_0.9Sr_0.1TiO₃ doped-perovskite nanoparticles and oxygen vacancies in La_0.9Sr_0.1CrO_3-δ doped-perovskite nanoparticles. The oxygen vacancies, which decrease columbic repulsion between protons and positive ions, have a more important role than the cation vacancies. They provide high surface area and high interfacial interaction between La_0.9Sr_0.1CrO_3-δ doped-perovskite nanoparticles, phosphoric acid, and polybenzimidazole for proton transfer and increase the proton conductivity of the nanocomposite membranes. In addition, the results of relative humidity effects showed that the ordered arrangement of oxygen vacancies of the La_0.9Sr_0.1CrO_3-δ doped-perovskite nanoparticles creates a specific pathway in the nanocomposite membranes for increasing proton transfer in the presence of relative humidity. Furtheremore, at phosphoric acid doping level of 13 mol phosphoric acid per monomer unit, proton conductivity of the nanocomposite membranes containing 8 wt.% La_0.9Sr_0.1CrO_3-δ doped-perovskite nanoparticles was obtained as 126 mS cm^-1 at 180°C and 6% relative humidity. The nanocomposite membrane showed the best performance and the power density of 0.62 W cm^-2 at 180°C and 0.5 V.     

S-arylation of 2-mercaptobenzazoles: a comprehensive review

In recent years 2-arylthio-benzazoles (benzothiazoles, benzoxazoles, and benzimidazoles) have attracted more and more attention due to their diverse biological and pharmacological properties. Consequently, great efforts have been devoted to exploiting efficient strategies towards the synthesis of titled compounds. Among the different methods reported for the synthesis of 2-arylthio-benzazoles, the most general and applicable one consists of the C–S cross-coupling of corresponding 2-mercaptobenzazoles with various electrophilic coupling partners. This protocol has advantages of the easily accessible starting materials, satisfactory yield of products, broad substrate scope, and high generality which makes it a useful and attractive method for the construction of various 2-arylthio-benzazoles. In this review, we highlight the significant advances achieved in this field from 1987 to 2017, with special emphasis on the mechanistic aspects of the reactions.     

Crystal and morphology development in immiscible nonpolar polymer blend nanocomposite based on low-density polyethylene and linear low-density polyethylene in presence of clay and compatibilizer

In this work, polyolefin-blend/clay nanocomposites based on low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and organically modified clay (OC) were prepared by melt extrusion. Various grades of maleic anhydride (MA) grafted polyethylene (PE-g-MA) were used and examined as compatibilizers in these nanocomposites. Differential scanning calorimetry analysis showed that OC and compatibilizer affect the crystallization behavior of LDPE/LLDPE with different mechanisms. Thermodynamic calculations of wetting coefficient based on interfacial energy between OC, LD, and LL, Morphological characterization based on field emission scanning electron microscopy, X-ray diffraction, small angles X-ray scattering, and dynamic rheology measurements revealed that the compatibilizer and OC were localized at the interface of LDPE and LLDPE phases with a preferred tendency toward one phase. Results demonstrated that at a specific amount of OC, there is an optimum compatibilizer concentration to achieve nanodispersed OC and beyond that the compatibilizer causes a structural change in the polymer crystalline morphology. It was also found that the tensile property enhancement of LDPE/LLDPE/OC nanocomposites is closely related to the crystalline structure development made by incorporation of both OC and compatibilizer.     

Preparation and characterization of polymer/multiwall carbon nanotube/nanoparticle nanocomposites and preparation of their metal complexes

Carbon nanotube‐polymer nanocomposites were synthesized and characterized successfully. In this work, multiwall carbon nanotubes (MWCNT) were opened using HNO₃/H₂SO₄ mixture and filled by metal nanoparticles such as silver nanoparticles through wet‐chemistry method. The oxidized MWCNT were reacted subsequently with thionyl chloride, 1,6‐diaminohexane, producing MWNT‐amine functionalized. Then the MWCNT containing metal nanoparticles were used as a monomer with different weight percentages in melt polymerization with An and CNCl separately. Furthermore, the polyamide and polytriazine modified MWCNT were used for the preparation of metal ion complexes such as Fe⁺² and La⁺³. The structures and properties of nanocomposites were evaluated by TEM, DSC, TGA, and FT‐IR methods. The chelating behavior and sorption capacities of prepared nanocomposites were carried out by using some metal ions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

An Improved Method for Edge Detection and Image Segmentation Using Fuzzy Cellular Automata

Image segmentation is one of the most important and challenging problems in image processing. The main purpose of image segmentation is to partition an image into a set of disjoint regions with uniform attributes. In this study, we propose an improved method for edge detection and image segmentation using fuzzy cellular automata. In the first stage, we introduce a new edge detection method based on fuzzy cellular automata, called the texture histogram, and empirically demonstrate the efficiency of the proposed method and its robustness in denoising images. In the second stage, we propose an edge detection algorithm by considering the mean values of the edges matrix. In this algorithm, we use four fuzzy rules instead of 32 fuzzy rules reported earlier in the literature. In the third and final stage, we use the local edge in the edge detection stage to more accurately accomplish image segmentation. We demonstrate that the proposed method produces better output images in comparison with the separate segmentation and edge detection methods studied in the literature. In addition, we show that the method proposed in this study is more flexible and efficient when noise is added to an image.     

A thermo/pH/magnetic-responsive nanogel based on sodium alginate by modifying magnetic graphene oxide: Preparation,characterization, and drug delivery

A novel thermo/pH/magnetic-triple-responsive nanogel was synthesized by grafting N-isopropylacrylamide and acrylic acid onto sodium alginate to modify magnetic graphene oxide as a drug delivery system. The synthesized nanogel was characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), atomic force micrographs (AFM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The obtained nanogel displayed excellent reversible transmittance changes in response to pH, temperature, and magnetic field. The performance of the nanogels to load doxorubicin (DOX) drug and to sustain doxorubicin release was tested upon exposure to pH, temperature, and magnetic field variations. The mechanism of drug release was proposed in this paper by different kinetic models. In addition, the effects of nanogels and DOX-loaded nanogels on MCF-7 cells were examined and results were compared with free DOX drug. The in vitro results demonstrated that this triple-responsive nanogel can be an appropriate candidate for applications in cancer therapy.     

Phase Morphology,Thermal, Thermomechanical and Interfacial Properties of PP/SAN/SBS Blend Systems

The effect of styrene–butadiene–styrene content on morphology, melting, crystallinity, dynamic mechanical properties and relaxation processes of polypropylene/poly(styrene-co-acrylonitrile)/styrene–butadiene–styrene blends was investigated. Styrene–butadiene–styrene reduced the average size of dispersed particles and generated complex aggregates in the matrix. Morphology development examined by dynamic mechanical thermal analysis showed increased damping of poly(styrene-co-acrylonitrile) domains at high styrene–butadiene–styrene contents. All blends showed reduced crystallinity and melting point compared with neat polypropylene. Poorer nucleation effect of dispersed particles at high styrene–butadiene–styrene loadings was observed. Compatibilization accelerated the form relaxation of dispersed particles. Additional relaxation process probably due to styrene–butadiene–styrene chains was observed in blends containing 10% and higher styrene–butadiene–styrene content.     

Assessment of supercapacitive performance of europium tungstate nanoparticles prepared via hydrothermal method

Nano-sized europium tungstate particles were prepared by reacting europium nitrate hexahydrate and sodium tungstate solutions, and the structures, morphology and optical properties of the product were evaluated by XRD, FT-IR, SEM, and UV–Visible techniques. The Eu₂(WO₄)₃ nanoparticles were evaluated as potential materials for constructing supercapacitor electrodes using the results of cyclic voltammetry, galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy and the electrodes were found to have a specific capacitance (SC) value of 347 F g^?1 in a 2.0 M H₂SO₄ electrolyte at a scan rate of 2 mV s^?1. The electrodes were further studied at the GCD at a current density of 1 A g^?1, and the SC of the building material was found to be 282 F g^?1. The cycling durability of the electrodes was also found to be excellent. After 4000 cycles the SC values of the electrodes were found to reach 129%. The preparation method and the resulting nano-particles, were hence found to be promising for high performance energy applications.