Application of enzymes and chitosan biopolymer to the antifelting finishing process

We surveyed environmentally friendly chemicals and mild processes that could be used to avoid the high absorbable organic halogen compounds (AOX) load and damage to the environment from the waste of wool plants. In this research, we sought to achieve a new zero‐AOX processing alternative to conventional processes such as chlorine/Hercosett processing and thus use environmentally friendly enzymes and chitosan as a biopolymer. We studied enzymatic, oxidative, and additive processes and various combinations of them to improve the shrink‐proofing and antifelting properties of wool. We performed our experiments with enzymatic treatments using commercial protease preparations, such as Perizym AFW, Alcalase 2.5L, Savinase 16L, and papain. The oxidative agents were hydrogen peroxide and sodium hypochloride, and the additive agents were based on polyurethane, polysiloxane, and silicone, as well as chitosan, a hydrophilic and natural polymer. We attempted to determine the agent or combination that best improved the shrink‐proofing properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2903–2908, 2004     

Surface modification of protein nanocontainers and their self-directing character in polymer blends

Tailoring the surfaces of a nanocontainer with polymer brushes that have different affinities to the components of a phase-separating polymer blend should impart self-directing properties to the nanocontainers. Such nanocontainers could then be used to deliver a variety of functional species in tunable amounts and in a site-specific manner to polymer systems. This paper describes the surface modification, subsequent characterization of nanocontainers derived from ferritin, and the effects of surface modification on their self-directing properties in a binary phase-separating homopolymer blend. Wild ferritin was either PEGylated or alkylated by zero-length cross-linking to its surface carboxylate groups that were activated by carbodiimide. Modification was confirmed by ion-exchange chromatography, ζ-potential measurement, and electrospray ionization mass spectrometry. FT-IR spectrometry was used to quantify the extent of PEGylation by ratioing the intensity of the C-O-C asymmetric stretching vibration from the grafted PEG to that of the carbonyl stretching vibration (amide I band) from the protein. Importantly, modified ferritin was soluble in the organic solvent dichloromethane (DCM). Modified ferritin was introduced into a polymer blend of hydrophobic and hydrophilic polymers made up of poly(desaminotyrosyl tyrosine dodecyl ester carbonate) (PDTD) and PEG by solvent casting from solution in the common solvent DCM. Polymer thin films with an average thickness of ∼200 μm were obtained upon evaporation of the solvent. Transmission electron micrographs of microtomed polymer films demonstrated remarkable selectivity of PEGylated ferritin to PEG domains, while alkylated ferritin self-directs to the PDTD matrix.     

A compact rail-to-rail CMOS buffer amplifier with very low quiescent current

In this work, a very compact, rail-to-rail, high-speed buffer amplifier for liquid crystal display (LCD) applications is proposed. Compared to other buffer amplifiers, the proposed circuit has a very simple architecture, occupies a small number of transistors and also has a large driving capacity with very low quiescent current. It is composed of two complementary differential input stages to provide rail-to-rail driving capacity. The push–pull transistors are directly connected to the differential input stage, and the output is taken from an inverter. The proposed buffer circuit is laid out using Mentor Graphics IC Station layout editor using AMS 0.35 μm process parameters. It is shown by post-layout simulations that the proposed buffer can drive a 1 nF capacitive load within a small settling time under a full voltage swing, while drawing only 1.6 μA quiescent current from a 3.3 V power supply.     

Micro- and nano-encapsulation of limonene and permethrin for mosquito repellent finishing of cotton textiles

Iranian Polymer Journal - The aim of this study was to prepare mosquito repellent textiles. To compare bio-based and synthetic mosquito repellent agents, limonene and permethrin were encapsulated...     

A novel design of high performance multilayered cylindrical dielectric lens antenna using 3D printing technology

In this work, design and realization of high performance, low‐cost X‐band multilayered cylindrical dielectric lens antenna (MLCDLA) is presented using 3D printing technology. Firstly, MLCDLA is designed and simulated in the complete 3D CST microwave studio (MWS) within the X‐ band as consisting of six layers and being fed through a conventional rectangular waveguide (WR90). These layers are in the form of cylindrical discs having different radii, thicknesses and made of a cheap polylactic acid material. These layers have also varying dielectric constant from 1.2 to 2.7 that are compatible for fused deposition modeling (FDM) based 3D‐printing process. Secondly, a prototype of MLCDLA is produced by using a FDM based 3D‐printer. 3D printed dielectric lens antenna is measured and a good return loss of almost more than 10 dB within the X‐band with a high gain of 16‐18 dBi are achieved as compared with the counterpart alternative designs. Thus, it can be concluded that the proposed novel design and prototyping method not only achieves the high radiation performance characteristics along X‐band but also is a fast, low‐cost, and effective method for prototyping dielectric lens structures for the microwave applications.     

Photochromic microcapsules by coacervation and in situ polymerization methods for product-marking applications

Photochromic materials can change their colour quickly and reversibly when exposed to light of certain wavelengths. These materials have recently been of great interest for intelligent and functional textile applications. In this study, two different photochromic dyes, including 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2′-(2H)-indole] and 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole], were microencapsulated by coacervation and in situ polymerization methods. Ethyl cellulose and melamine–urea–formaldehyde were used as polymers. The Fourier transform infrared spectroscopy, particle size and size distribution analysis, scanning electron microscopy, and ultraviolet spectrophotometry evaluations were utilized to characterize the structure, morphology, size distribution, and absorbance maxima of the photochromic microcapsules. The results indicated that photochromic microcapsules were in spherical shape, smooth, and homogeneous characteristics. These microcapsules were applied successfully onto cotton fabric using printing technique. Then, the activities of photochromic microcapsules on the fabrics were analysed by colour analysis under different light sources, fatigue resistance, washing, and rubbing fastness tests. After printing, the colours of the fabrics changed very quickly under different light sources. At the same time, these fabrics showed a reversible photochromic response and good fatigue resistance. Mechanical and physical properties of the fabrics such as thickness, air permeability and tensile and tear strength were also investigated. It can be concluded that photochromic microcapsules are well appropriate for brand protection and prevention of imitation in textile materials.     

Covalent organic framework based on melamine and dibromoalkanes for versatile use

Covalent organic frameworks (COFs), based on melamine and dibromoalkanes [Br(CH₂)_nBr] with n = 2, 4, 6, and 8 for 1,2-dibromoethane, 1,4-dibromobutane, 1,6-bibromohexane and 1,8-dibromooctane as COF-1,2, COF-1,4, COF-1,6, COF-1,8, were synthesized in dimethyl sulfoxide at 150 °C. The COFs had distinct color depending on the number of C atoms (n) in the dibromoalkanes e.g., light-yellow, intense yellow, brown and dark brown for COF-1,2, COF-1,4, COF-1,6, and COF-1,8, respectively. Furthermore, it was demonstrated that COF-1,2 and COF-1,4 COFs can be used as a template for in situ Co metal nanoparticle preparation by loading CoCl₂ salt from ethanol solution into COFs and then treating with NaBH₄ solution. Then the prepared catalyst systems of COF-1,2-Co and COF-1,4-Co were tested for H₂ generation from hydrolysis of NaBH₄. The COF-1,2-Co composite materials showed better catalyst performance than COF-1,4-Co composite in the hydrolysis of NaBH₄. The hydrogen generation rates (HGR) and turnover frequency values were calculated as 1589 and 594 ml H₂/(g of catalyst) × (min) HGR values, and 3.75 and 1.41 mol H₂/(mol catalyst min) for COF-1,2-Co and COF-1,4-Co composite materials, respectively. The room temperature conductivities were measured and the highest conductivity was measured as 2.26E?07 S cm^?1 for COF-1,2-(CoCl₂). The COF also had fluorescent properties and their emission wavelengths reduced in the presence of Co nanoparticles depending on the n values of the dibromoalkanes.     

Reaction Kinetics of Ozone with Selected Pharmaceuticals and Their Removal Potential from a Secondary Treated Municipal Wastewater Effluent in the Great Lakes Basin

Oxidation kinetics of selected pharmaceutical compounds and their degradation during ozonation of secondary treated municipal wastewater effluent (MWWE) was investigated. The apparent second-order rate constants for the reaction between chlorotetracycline (CTC), enrofloxacin (ENR), gemfibrozil (GEM) and ozone ranged between 6.82 – 52.7 × 10⁴ M^?1s^?1. The measured second-order hydroxyl radical rate constants were several orders of magnitude higher at 8.4 × 10⁹ – 13.1 × 10⁹ M^?1s^?1 with a reactivity sequence of GEM > CTC > ENR. Overall degradation of CTC, ENR and GEM in secondary treated municipal wastewater effluent was >76 % at ozone doses of 0.33 mg O₃/mg DOC or higher.     

A flexible current‐mode classifier circuit and its applications

In this paper a new CMOS classifier circuit is presented, simulated, and compared with other recently introduced circuits. The proposed CMOS circuit operates in current‐mode and can classify several types of data. The architecture is designed using two threshold circuits and a subtraction circuit. Among many possible applications of the classifier circuit, template‐based pattern classification, namely template matching and character recognition with corruption, and in another direction its use as a quantizer are given. Using 0.35‐ µm AMS technology parameters, SPICE simulations as well as hard realization results for the classifier and application circuits are included; detailed Monte Carlo analyses to assess parameter mismatch effects are also performed. Copyright © 2010 John Wiley & Sons, Ltd.