Influences of aminosilanization of halloysite nanotubes on the mechanical properties of polyamide‐6 nanocomposites

The main purpose of this study was to explore effects of silanization of halloysite nanotubes (HNT) on the mechanical properties of polyamide 6 by using aminopropyltriethoxysilane. Effects of two silanization parameters; “initial silane concentration” and “pH of reaction solution” were also investigated. Nanocomposites were compounded via melt mixing method in a twin‐screw extruder, while specimens were shaped by injection molding. Formation of aminosilane molecules on the edges and defected surfaces of HNTs were revealed mainly by Fourier‐Transform infrared spectroscopy. Scanning electron microscopy and mechanical tests indicated that even the use of unmodified HNTs could be homogenously distributed in the matrix leading to increased mechanical properties as much as more than 30%. Aminosilanization of HNTs with optimum silanization parameters resulted in effective amounts of Al O Si bridging bonds between the matrix and reinforcement, making composite strengthening mechanisms more operative. In this condition, increases in the mechanical properties were as much as more than 50%. POLYM. COMPOS., 35:1350–1361, 2014. © 2013 Society of Plastics Engineers     

Equalizing effect of β‐cyclodextrin on dyeing of polyamide 6,6 woven fabrics with acid dyes

Cyclodextrins (CD) are produced from starch by the action of cyclodextrin glycosyltransferase (CGTase) enzyme. Structurally, cyclodextrins consist of 6, 7, or 8 (α, β, and γ cyclodextrins, respectively) D‐glucopyranosyl units connected by α‐(1,4) glycosidic linkages. Having polar and hydrophilic outer sides and hydrophobic cavitation gives cyclodextrins a chance to form inclusion complexes with dyes in hydrophilic mediums. In this research, the equalizing effect of β‐cyclodextrins in dyeing of polyamide 6,6 woven fabrics with 6 different acid dyes were investigated. From the experimental results, it was determined that the β‐cyclodextrin shows a retarding and equalizing effect in dyeings carried out with the dyes that show interaction with β‐CD. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2660–2668, 2007     

Polyphenols,carotenoids, and ascorbic acid in underutilized medicinal vegetables

The polyphenols, carotenoids, ascorbic acid, and protein were determined in 24 underutilized medicinal vegetables from Indonesia. Anacardium occidentale, Sauropus androgynus (L.) Merr., and Moringa pterygosperma Gaertn. leaves were rich sources of flavonoids, with 118–144 mg/100 g fresh weight. Quercetin, kaempferol, and chlorogenic acid were the predominant polyphenols among those measured in vegetables. Polyscias pinnata leaves and Solanum torvum Swartz fruits had the most phenolic acids, with 53 and 36 mg/100 g, respectively. Moringa pterygosperma had the most carotenoids among vegetables, with 14 mg β-carotene equivalents (βCE)/100 g. Ascorbic acid content of fresh vegetables was 12.03–494.43 mg/100 g. A. occidentale, S. androgynus, Ocimum americanum L., Cosmos caudatus H.B.K., and Carica papaya L. (papaya) leaves had more than 100 mg ascorbic acid/100 g. Thus, a number of underutilized vegetables from Indonesia may be rich sources of functional components including polyphenols and ascorbic acid.     

Electronically controlled agile lens-based broadband variable photonic delay line for photonic and radio frequency signal processing

To the best of our knowledge, proposed for the first time is the design of an optically broadband variable photonic delay line (VPDL) using an electronically controlled variable focus lens (ECVFL), mirror motion, and beam-conditioned free-space laser beam propagation. This loss-minimized fiber-coupled VPDL design using micro-optic components has the ability to simultaneously provide optical attenuation controls and analog-mode high-resolution (subpicoseconds) continuous delays over a moderate (e.g., <5 ns) range of time delays. An example VPDL design using a liquid-based ECVFL demonstrates up to a 1 ns time-delay range with >10 dB optical attenuation controls. The proposed VPDL is deployed to demonstrate a two-tap RF notch filter with tuned notches at 854.04 and 855.19 MHz with 22.6 dB notch depth control via VPDL attenuation control operations. The proposed VPDL is useful in signal conditioning applications requiring fiber-coupled broadband light time delay and attenuation controls.     

Liquid crystal-based optical control of phased array antennas

Nematic liquid crystal (NLC) technology-based optical systems for controlling phased array antennas are presented. These systems can provide low-cost, high-quality (>6-b), phase-based antenna control for very large phased arrays (e.g. 5000 elements). An experiment demonstrating NLC-based antenna phase control is performed, with 0-3π phase shift measured for a 60-MHz carrier. A novel time-multiplexed radar beam scanning approach is introduced to counter the slow response of the NLCs, allowing fast 200 beams/s antenna scanning rates     

Bulk acousto-optic wavelength agile filter module for a wavelength-multiplexed optical scanner

An acousto-optic tunable filter-based wavelength-selection module with features optimized for a wavelength-multiplexed optical scanner (W-MOS) is proposed and demonstrated. The W-MOS produces high-speed multiple scan beams if it is engaged with an agile tunable source with multiwavelength generation capability. In particular, the proposed fiber-connected module features high-speed, low-loss, narrow-linewidth, and single-multiple wavelength selection by means of radio frequency drive signal control for single- or multiple-beam scan operations. The unique module offers input laser beam power control that in turn delivers the desired scanned laser beam power shaping. Experimental results match module design theory and demonstrate a fast 5.4-micros wavelength selection speed, a low (1.53-dB) fiber-to-fiber optical insertion loss, a 5.55-nm 3-dB spectral width, and a 1500-1600-nm agile wavelength operational band.     

Phased-array antenna, maximum-compression, reversible photonic beam former with ternary designs and multiple wavelengths

A novel, switched, photonic delay-line ternary design combined with a wavelength-multiplexed transmit-receive beam-former architecture is proposed. One-dimensional antenna beam steering by use of a single-channel, wavelength-dependent switched photonic delay line in cascade with a multichannel wavelength-independent switched photonic delay line is proposed for hardware-compressed, phased-array antenna control with subarray antenna partitioning. Beam-former architecture extensions to two-dimensional antenna beam steering are described.     

Directly modulated semiconductor-laser-fed photonic delay line with ferroelectric liquid crystals

A 3-bit binary photonic delay line is demonstrated at 1 GHz by use of a directly modulated semiconductor laser and remote interconnection fiber optics. Three types of free-space delay-bit geometries are tested for 5.69-ns, 1.67-ns, and 8.8-ps designed delay bits. This is the first time, to our knowledge, that a photonic delay line is demonstrated with ferroelectric liquid-crystal optical on-off devices for optical path switching and active polarization noise filtering. Three-dimensional imaging optics and antireflection-coated optics (for all but five components) are used successfully to minimize photonic delay-line insertion losses and interchannel cross talk. The 3-bit system is fully characterized for measured and designed performance.     

A flexure motion stage system for light beam control

This paper presents the design of an improved tip-tilt-piston compliant/flexure motion stage for steering light beam. The motion stage is actuated by three linear stepper motors in an open-loop control. Using a laser and optical setup, the completed device was tested by making it steer a laser beam, effectively demonstrating its range of movement and level of precision. The testing has proved that the new motion stage system has a maximum bidirectional rotation range of at least 2.89° with a precision and repeatability of 0.0213°, demonstrating a micro-positioning ability.