Synthesis and Characterization of ZnO Nanoparticles via Thermal Decomposition of Two Zinc(II) Supramolecular Compounds

A new nano-sized Zn(II) complex, [Zn(5,5′-dtbu-2,2′-bipy)Cl₂] _n (1) was synthesized and its structure determined by X-ray crystallography. The new nano-sized complex was prepared at oleic acid as a surfactant at 280 °C and characterized by scanning electron microscopy, elemental analyses and IR spectroscopy. The ZnO nano-particles were synthesized from thermolysis of nano-compound 1 at 600 °C and similar compound, [Zn(5,5′-dimethyl-2,2′-bipy)Cl₂] _n (2), at two different methods. SEM images show the average size of ZnO nano-particles are 78 and 50 nm for the compounds 1 and 2, respectively.     

Electrospun core–shell nanofibers for drug encapsulation and sustained release

Fabrication of core–shell nanofibers by coaxial electrospinning system suited for drug delivery applications was investigated based on tetracycline hydrochloride (TCH) as the core and poly(lactide‐co‐glycolide) as the shell materials. Comparison of drug release from monolithic fibers (blend electrospinning) and core–shell structures was performed to evaluate the efficacy of the core–shell morphology. The nanofibrous webs are potentially interesting for wound healing purposes since they can be maintained for an adequate length of time to gradually disinfect a local area without the need of bandage renewal. Further, our studies showed the potential of core–shell nanostructures for sustained drug release, which also suppressed the burst release effect from 62 to 44% in the first 3 hours by adding only 1 wt% TCH to the polymeric shell. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

Optimization of the Production of Biosurfactant From Iranian Indigenous Bacteria for the Reduction of Surface Tension and Enhanced Oil Recovery

Abstract

The optimum conditions for biosurfactant production by Iran's isolates were examined. The Taguchi method was used to identify nutritional requirements in the medium using four parameters; that is, carbon source, nitrogen, phosphorous, and salt concentrations. The use of whey, oil, and sucrose as carbon sources; NaCl as salt source; (Na₂HPO₄, NaH₂PO₄) as phosphorous source; and (NH₄)₂SO₄ as nitrogen source was examined to determine bacteria optimum conditions. According to the Taguchi method using the sucrose source, the optimal conditions for Bacillus subtilis were 50 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄)₂SO₄; for Bacillus cereus they were 25 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄)₂SO₄; and for Pseudomonas putida they were 25 g/L NaCl, 13.53 g/L (Na₂HPO₄, NaH₂PO₄), and 1 g/L (NH₄2_SO. Oil displacement experiments in the micromodel at optimum conditions showed around 25% recovery of residual oil with added supernatant of Bacillus subtilis.     

The role of geometry on the viscoelastic materials properties: tensile and stress relaxation of the yarn

The time-dependent mechanical behavior of textiles has particular importance. One of such behaviors is stress relaxation. When strain is applied constantly, there is a decreased stress with time in viscoelastic materials, which is called stress relaxation. The aim of this study is to investigate the effect of knot’s geometry (surgeon, square and eight) and the number of knots on the tensile and stress relaxation properties of the polyester yarn. Significant differences were observed for the tensile characteristics of the yarn in the presence of the knot. Generally, the knotted yarns demonstrated lower tensile stress and strain at failure. Moreover, the results revealed that the stress relaxation behavior of the yarn is affected by the number of knots and their geometry. The yarn without knot exhibited the highest stress relaxation percent while the yarn with the surgeon’s knot displayed the least stress relaxation percent. On the other hand, increasing the number of knots led to a decrease in the percentage of yarn stress relaxation.     

Development of a Date Confectionery: Part 1. Relating Formulation to Instrumental Texture

The Sultanate of Oman in the Middle East produces a large amount of dates, which in 2003 amounted to about 285,360 tons. Most of the harvest is used for animal feed and the rest for local consumption. The need to utilize dates in a more efficient way is a must. In this study, a new candy was developed using two date varieties, i.e., Khalas and Umesilla thus spanning from top to bottom of the quality range in terms of consumer preference. Proximate analysis argues that products are nutritious and can contribute especially to the daily allowance in macro-elements. Texture profile analysis suggests that the affordable date candy of Umesilla belongs to the same family of products with the Khalas candy in terms of the attributes of hardness, firmness, brittleness and adhesiveness. Products were aged up to thirteen weeks, with results demonstrating that the textural quality remains stable throughout the storage period.     

Fault‐tolerant control of distributed systems by information pattern reconfiguration

Given a fault‐tolerance strategy and a distributed control system, the set of recoverable faults depends on the information pattern that is implemented. This paper shows that fault‐tolerance can be achieved, when possible, by the reconfiguration of the information pattern. A necessary and sufficient recoverability condition is provided, and sub‐optimal solutions are developed for actuator and sensor faults under system reconfiguration. Copyright © 2014 John Wiley & Sons, Ltd.     

Distance metrics for very large color differences

Small, supra-threshold color differences are typically described with Euclidean distance metrics, or dimension-weighted Euclidean metrics, in color appearance spaces such as CIELAB. This research examines the perception and modeling of very large color differences in the order of 10 CIELAB units or larger, with an aim of describing the salience of color differences between distinct objects in real-world scenes and images. A psychophysical experiment was completed to compare directly large color-difference pairs designed to probe various Euclidean and non-Euclidean distance metrics. The results indicate that very large color differences are best described by HyAB, a combination of a Euclidean metric in hue and chroma with a city-block metric to incorporate lightness differences.     

Drop behaviour characteristics in different operating regimes in an L‐shaped pulsed sieve‐plate column

In this study, the influence of different operating regimes on drop behaviour in an L‐shaped pulsed sieve‐plate column has been investigated and the effects of pulsation intensity and phase superficial velocities on drop diameters are evaluated. The toluene‐water system with 0.03 L/L (3 vol%) acetone as a mass transfer agent is used. Experimental observations reveal that with increasing pulsation intensity, drop sizes slightly decrease and by reaching to the end of mixer‐settler regime, they significantly decrease followed by a mild decrease in the dispersion regime. Moreover, it is observed that mean drop size firstly varies inversely as both phase superficial velocities change, while it slightly increases with further increase in superficial velocities. Finally, some of the most recommended correlations are compared to the experimental data. It is revealed that these correlations show the highest deviation in the lower end of the mixer‐settler regime (> 40 %), while in the dispersion regime it becomes < 15 %, indicating that they are only applicable in the region of practical regimes. Accordingly, two of these correlations are modified in order to cover different operating regimes by means of two correlations proposed to predict the transition regime in each section of the column. The AARE values of the modified correlations are found to be < 14.7 %.     

Solving Hydropower Unit Commitment Problem Using a Novel Sequential Mixed Integer Linear Programming Approach

Hydro Unit Commitment (HUC) is an important problem of power systems and when it is dealt with via a mathematical programming approach and optimization, it leads to the complicated class of mixed-integer nonlinear programming (MINLP). Many attempts have been made to solve the problem efficiently, while there is still ongoing research to come up with better solution schemes in terms of runtime and optimality. Highly nonlinear nature of the relationships and constraints in the optimization problem have forced the researchers to deal with the HUC problem in simplified manners which may result in impractical and unreliable solutions, i.e. schedules. Here in this paper we proposed a new method based on sequential mixed-integer linear programming (MILP) for solving a more realistic version of the HUC problem efficiently. We applied the proposed method to a cascade of two hydropower plants, Karun-3 and Karun-4, located in the Southwest of Iran. The sequential MILP approach was compared with several MINLP solvers of the GAMS optimization package. The results indicated that the proposed methodology outperformed the MINLP solvers in terms of efficiency, with solution time of less than 30 s, compared to 10 min that were given to the solvers, and in terms of optimality with more than 20 thousand cubic meters per day in water release. Additionally, we have explored the effect of penalizing the total number of startups on the total release, convergence of the algorithm, and the computation time. In all of the cases the total number of startups was reduced more than three times.

     

Passive detection of image forgery using DCT and local binary pattern

With the development of easy-to-use and sophisticated image editing software, the alteration of the contents of digital images has become very easy to do and hard to detect. A digital image is a very rich source of information and can capture any event perfectly, but because of this reason, its authenticity is questionable. In this paper, a novel passive image forgery detection method is proposed based on local binary pattern (LBP) and discrete cosine transform (DCT) to detect copy–move and splicing forgeries. First, from the chrominance component of the input image, discriminative localized features are extracted by applying 2D DCT in LBP space. Then, support vector machine is used for detection. Experiments carried out on three image forgery benchmark datasets demonstrate the superiority of the method over recent methods in terms of detection accuracy.