Effect of copper nanoparticles on permeability, physical, and mechanical properties of particleboard

Effects of a 200 ppm nanocopper suspension, with size range from 10 to 80 nm, on the physical and mechanical properties of particleboard made on an industrial scale at the Iran-Choob Factory were studied. Nanocopper suspension was added to the mat at two levels of 100 and 150 ml/kg dry weight wood particles and compared with control boards. Results showed that hot-pressing time was reduced by 5.7 and 3.4 % when 100 and 150 ml of nanocopper were used, respectively. Also, both levels of nanocopper consumption had improving effects on physical and mechanical properties, although in some cases not significant. Permeability was significantly decreased to its lowest value in 150 ml/kg treatment. It can be concluded that 150 ml of nanocopper/kg may be used to improve the physical and mechanical properties, to reduce press time, and to decrease permeability in particleboards. For industrially accepted outcome, 150 ml/kg of nanocopper is recommended.     

A novel numerical technique for dielectric measurement of generallylossy dielectrics

A method for determining the dielectric properties of infinite half-space of generally lossy dielectric materials is described. This method utilizes the measurement of the admittance of a rectangular waveguide radiating into such dielectrics. It is shown that the real part of the admittance is relatively insensitive to the variations of the imaginary part of the dielectric constant. A numerical procedure is initiated which provides a simple and fast-converging approach for calculating the dielectric properties. This numerical procedure lends itself to implementation by personal computers. The theoretical formulation for the expression of the admittance of an open-ended waveguide and the numerical procedure are discussed in detail. Results of several measurements of freespace and lossy dielectric samples (rubber with carbon black) to verify the theory and the numerical scheme are given. The results give good agreement with other measurement schemes. Comments on the accuracy of the results are also provided     

Document Image Coding for Processing and Retrieval

Document images belong to a unique class of images where the information is embedded in the language represented by a series of symbols on the page rather than in the visual objects themselves. Since these symbols tend to appear repeatedly, a domain-specific image coding strategy can be designed to facilitate enhanced compression and retrieval. In this paper we describe a coding methodology that not only exploits component-level redundancy to reduce code length but also supports efficient data access. The approach identifies and organizes symbol patterns which appear repeatedly. Similar components are represented by a single prototype stored in a library and the location of each component instance is coded along with the residual between it and its prototype. A representation is built which provides a natural information index allowing access to individual components. Compression results are competitive and compressed-domain access is superior to competing methods. Applications to network-related problems have been considered, and show promising results.     

Honey-Bees Mating Optimization (HBMO) Algorithm: A New Heuristic Approach for Water Resources Optimization

Over the last decade, evolutionary and meta-heuristic algorithms have been extensively used as search and optimization tools in various problem domains, including science, commerce, and engineering. Their broad applicability, ease of use, and global perspective may be considered as the primary reason for their success. The honey-bees mating process may also be considered as a typical swarm-based approach to optimization, in which the search algorithm is inspired by the process of real honey-bees mating. In this paper, the honey-bees mating optimization algorithm (HBMO) is presented and tested with few benchmark examples consisting of highly non-linear constrained and/or unconstrained real-valued mathematical models. The performance of the algorithm is quite comparable with the results of the well-developed genetic algorithm. The HBMO algorithm is also applied to the operation of a single reservoir with 60 periods with the objective of minimizing the total square deviation from target demands. Results obtained are promising and compare well with the results of other well-known heuristic approaches.     

Preparation and characterization of novel derivatives of chitosan and trimethyl chitosan conjugated with dipeptides and vitamin B12 as candidates for oral delivery of insulin

Chitosan and its derivatives are widely used in drug delivery systems due to their bio-degradebility, bio-compatibility and absorption enhancing properties. Many peptide and protein derived therapeutics cannot be administered through oral rout because of the proteolytic condition of gastro-intestinal tract and their low bio-availability. Insulin is a peptide drug which is widely used in diabetics as repeated daily injection. Due to the fact that there are receptors for didpeptides and vitamine B12 in small intestine, in this research work novel derivatives of chitosan and trimethyl chitosan conjugated with glycyl-glycine, alanyl-alaninie and vitamine B12 were synthesized and characterized. The structure of conjugates as well as substitution of different functional groups was confirmed by different instrumental analytical methods such as Fourier transform infrared, magnetic resonance, and X-ray diffraction spectroscopy. Nano-particles of aforementioned loaded with insulin were prepared and their size, surface electrical charge and morphology characterized and their release profile were studied. The results are promising and reveal that these new chitosan and trimethyl chitosan derivatives are potential vehicles for protein and peptide drug molecules.     

A SAR-based ΣΔ modulator using shared DAC

In this paper a new successive approximation (SA) quantizer based on the elimination of the digital to analog converter (DAC) from the quantizer structure is presented. Instead; the feedback DAC block of the ΣΔ modulator is shared by SA quantizer. Using an efficient decoding algorithm in the proposed structure in conjunction with the above SA quantizer DAC elimination method, results in a reduction of the level number of the feedback DAC, and hence, a significant drop in power and area consumption is achieved. In order to study the performance of the proposed structure, a third order discrete-time ΣΔ modulator is designed and simulated in 0.18 μm CMOS technology with the following performance characteristics; a signal to noise ratio of 79.2 dB, dynamic range of 84.8 dB, power consumption of 3.75 mW and a figure of merit of 0.66 pJ/conv from a 1.8 V supply with an input signal of 200 kHz bandwidth.     

Ellagic acid promoted biomimetic synthesis of shape-controlled silver nanochains

In this work, ellagic acid (EA), a naturally occurring plant polyphenol, was utilized for the biomimetic synthesis of silver (Ag) nanoparticles, which over a period of time formed extended branched nanochains of hexagonal-shaped silver nanoparticles. It was found that EA not only has the capability of reducing silver ions, resulting in the formation of Ag nanoparticles, due to its extended polyphenolic system, but also appears to recognize and affect the Ag nanocrystal growth on the (111) face, leading to the formation of hexagon-shaped Ag nanocrystals. Initially, various Ag nanocrystal shapes were observed; however, over a longer period of time, a majority of hexagonal-shaped nanocrystals were formed. Although the exact mechanism of formation of the nanocrystals is not known, it appears that EA attaches to the silver nuclei, leading to lower surface energy of the (111) face. Further, the nanocrystals fuse together, forming interfaces among the aggregates, and, with time, those interfaces become lesser, and the nanoparticles merge together and share the same single crystallographic orientation, which leads to the formation of long elongated chains of hexagonal nanoparticles. This biomimetic approach may be developed as a green synthetic method to prepare building blocks with tunable properties for the development of nanodevices. Further, we explored the antibacterial properties and found that the tandem of EA-Ag nanochains substantially enhanced the antibacterial properties of both gram-positive and gram-negative bacteria compared to silver nanoparticles or EA alone. Additionally, the materials were also utilized for imaging of mammalian NRK (normal rat kidney) cells.     

Differential current conveyor based current comparator

A New differential current conveyor based current comparator is presented in this paper. Differential current conveyor II (DCCII) is designed, modified, and exploited as a comparator with reduced propagation delay and power consumption. New DCCII decreases propagation delay and increases comparator accuracy considerably. Simulation results using Hspice and 0.18 μm CMOS technology with 1.8V supply voltage confirms a less than 0.63 ns propagation delay at ±1 μA input current. Average power dissipation in ±1 μA input current has a value of 300 μW.     

Improving thin-film manufacturing yield with robust optimization

A novel robust optimization algorithm is demonstrated that is largely deterministic, and yet it attempts to account for statistical variations in coating. Through Monte Carlo simulations of manufacturing, we compare the performance of a proof-of-concept antireflection (AR) coating designed with our robust optimization to that of a conventionally optimized AR coating. We find that the robust algorithm produces an AR coating with a significantly improved yield.     

Open-ended rectangular waveguide for nondestructive thicknessmeasurement and variation detection of lossy dielectric slabs backed bya conducting plate

Solutions for fields inside a slab of a generally lossy dielectric medium backed by a conducting plate, placed outside a waveguide-fed rectangular aperture, are used for the microwave nondestructive thickness measurement of such dielectric slabs. Upon construction of the waveguide terminating admittance expression from its variational form, an inverse problem is solved to extract the slab thickness form the conductance and susceptance in a recursive manner. A comparison between the experimental and theoretical results showed that the significance of higher order modes is minimal; hence, the dominant mode assumption is, in general, valid for describing the aperture field distribution. The validity of this assumption has led to the construction of a simple integral solution which is fast converging for generally lossy dielectric slabs, and may easily be implemented for real-time applications. Good agreement was obtained between the theoretical and experimental results. Multiple thicknesses of two different dielectric samples were estimated in this way