Synthesis of Multiwalled Carbon Nanotubes–Poly(Methacrylic Acid) Nanohybrid Systems: Characterization,Thermal Properties,and In Vitro Release Studies of Naproxen as a Model Drug

Nanohybrid systems based on carbon nanotubes and pH-sensitive poly(methacrylic acid) were prepared through attaching polymer chains onto carbon nanotubes. First, polymerizable groups were attached onto carbon nanotube walls, then the polymerizable groups were copolymerized with different ratios of methacrylic acid. Obtained systems were studied and characterized through Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. A model drug (naproxen) was entrapped into the prepared materials and in vitro release studies were performed in pH 1 (simulated gastric fluids) and pH 7.4 (simulated intestinal fluids). It was noticed that release in simulated intestinal fluids was faster than simulated gastric fluids, therefore the prepared nanohybrid systems can be considered as appropriate carriers for colon-specific drug delivery.     

The comparative study of photocatalytic self‐cleaning properties of synthesized nanoscale titania and zirconia onto polyacrylonitrile fibers

The photocatalytic activity of TiO₂ and ZrO₂‐coated polyacrylonitrile (PAN) fibers was compared through the self‐cleaning of methylene blue and eosin yellowish. TiO₂ and ZrO₂ nanocrystals were successfully synthesized and deposited onto PAN fibers with photocatalytic self‐cleaning activity using the sol‐gel process at low temperature. The pristine and treated samples have been characterized by several techniques, such as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, X‐ray diffraction, and thermogravimetric analysis. The TiO₂ nanoparticles with 10–20 nm in size, and ZrO₂ with 20–40 nm have been synthesized to form dispersed particles on the fiber surface, which shows photocatalytic properties when exposed to UV–Vis light. The photocatalytic activity, tested by measuring the degradation of adsorbed methylene blue and Eosin Y. Photocatalytic activity of TiO₂‐coated fibers toward dyes degradation was higher than that of ZrO₂‐coated fibers. This preparation technique can be also applied to new fabrics to create self‐cleaning and UV irradiation protection properties in them. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Fatigue life enhancement of automobile wheel disc considering multi-axial stresses based on critical plane approach

Journal of Mechanical Science and Technology - We report an optimization procedure of automobile steel wheel fatigue life enhancement considering multi axial stresses based on critical plane...     

A Fully Programmable Analog CMOS Rational-Powered Membership Function Generator with Continuously Adjustable High Precision Parameters

This paper presents a novel structure for implementing rational-powered membership functions (RPMFs), which are the extended forms of triangular/trapezoidal membership functions and those functions which are generated by applying linguistic hedges. The hardware realization of an RPMF consists of a triangular membership function generator circuit followed by a rational-powered generator module (RPGM). A novel fully programmable compact triangular/trapezoidal/s-shaped/z-shaped membership function generator with the ability to continuously change parameters is presented which is compatible with the proposed RPGM. A new method is introduced to implement the RPGM based on the approximation of the function “x ^a ” by the functions square and square-rooter which are simply implemented in a current-mode analog approach based on the translinear principle, which leads to a design that is simple, and has high accuracy and less hardware usage, with a resulting lower chip area and lower power consumption. The designed circuit was simulated by an HSPICE simulator with level 49 parameters (BSIM3v3), and the simulation results show that the maximum power consumption of the RPGM is 800 μW, while the maximum RMS error is 1.25 %. Finally, layouts of the circuits prepared using Cadence software are presented.     

Rapid and Precise GLONASS GDOP Approximation using Neural Networks

Russian global navigation satellite system (GLONASS) provides civilian and military users three-dimensional position determination and navigation services as same as US global positioning system. Geometric dilution of precision (GDOP) provides a simple interpretation of positioning precision. Usual method for GLONASS GDOP calculation is matrix inversion. However this process imposes a huge calculation load on receiver, especially when large number of visible satellites exists. To overcome this problem, artificial neural network is used. Different configurations and training methods are simulated on a data base obtained by a GLONASS receiver. Then navigation precision and execution times are explored and compared. Results show that recurrent neural network has 0.00024 RMS error, which is the best against other focused tools including feed forward back propagation and radial basis function neural network with usual training and with genetic algorithm adopted weights and biases.     

Influence of additives on the morphology of PVDF membranes based on phase diagram: Thermodynamic and experimental study

In the present study, the morphology of asymmetric poly(vinylidene fluoride) blend membranes which were prepared by the phase inversion method is rationalized by comparing two non‐dimensional number represent thermodynamic and kinetic properties of the prepared membrane. These two parameters change phase diagram and demixing rate between solvent and nonsolvent. TiO₂ nanoparticles and polyvinylpyrrolidone were used as additives. Hansen solubility parameters of the components are calculated by Van Krevelen method. Furthermore, kinetic and thermodynamic properties of the prepared solutions are determined by drawing phase diagrams and controlling mass transfer rate during precipitation of casting solution. Besides, to further analyze different tests encompass; permeability, rejection, porosity, pore size determination, contact angle, and field emission scanning electron microscopy images were carried out. It is shown, additives as pore former induced higher permeability and porosity, however, at higher concentration of additives high viscosity obstacle mass transfer and sponge‐like morphology is obtained. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46225.     

Effects of drying methods on qualitative and quantitative properties of essential oil of two basil landraces

Sweet basil, a plant that is extensively cultivated in some countries, is used to enhance the flavour of salads, sauces, pasta and confectioneries as both a fresh and dried herb. To determine the effect of drying methods on qualitative and quantitative characteristics of the plant and essential oil of basil, two landraces, Purple and Green, were dried in sunlight, shade, mechanical ovens at 40 °C and 60 °C, a microwave oven at 500 W and by freeze-drying. For comparison, the essential oils of all samples were extracted by hydrodistillation and analyzed using GC and GC–MS. The highest essential oil yields (v/w on dry weight basis) were obtained from shade-dried tissue in both landraces followed by the freeze-dried sample of the purple landrace and the fresh sample of green landrace. Increasing the drying temperature significantly decreased the essential oil content of all samples. Significant changes in the chemical profile of the essential oils from each of the landrace were associated with the drying method, including the loss of most monoterpene hydrocarbons, as compared with fresh samples. No significant differences occurred among several constituents in the extracted essential oils, including methyl chavicol (estragole), the major compound in the oil of both landraces, whether the plants were dried in the shade or sun, oven at 40 °C or freeze-dried, as compared with a fresh sample. The percentage methyl chavicol in the oil, however, decreased significantly when the plant material was dried in the oven at 60 °C or microwaved. In addition, linalool, the second major compound in the purple landrace, and geranial and neral, major compounds in the green landrace, decreased significantly when the plant tissue was dried in the oven at 60 °C or microwaved.     

An all-digital DFT scheme for testing catastrophic faults in PLLs

Traditional functional testing of mixed-signal ICs is slow and requires costly, dedicated test equipment. The authors update the standard PLL architecture to allow simple digital testing. The all-digital strategy yields catastrophic fault coverage as high as that of the classical functional test, plus it is fast, extremely simple to implement, and requires only standard digital test equipment.