Stochastics multi-objective modelling of simultaneous reconfiguration of power distribution network and allocation of DGs and capacitors

This paper suggests a method based on stochastic multi-objective modelling for optimally siting and sizing of distributed generations and capacitors and simultaneously network reconfiguration, in order to take more advantages of recent developed technologies. With respect to the widespread effect of uncertainties of load forecasting and market price, some strategies must be devised so as to well incorporate them into the problem. The mentioned problem can be regarded as a multi-objective optimisation problem for which NSGA-II accompanied by fuzzy set theory are chosen. The main aim of DisCo is to provide highly reliable power at the lowest possible costs. Besides, voltage deviation and voltage stability as the criteria of power quality in distribution networks and emission pollutant reduction are treated as independent objective functions. Eventually, to validate the effectiveness of the proposed scheme, simulations are carried out and the results are compared to the initial configuration.     

Geometric quality assessment of in situ blocks in dimension stone quarries

The profitability of stone quarries depends on the appearance (color and texture) and, more importantly, on the size of the blocks, which is determined by the three-dimensional discontinuity pattern of the rock mass. However, to date there is no comprehensive criterion by which to assess the size of blocks in quarries. The aim of the study reported here is to identify factors that facilitate decision-making on the desirability of an individual block and ultimately on all blocks for extraction as a dimension stone. To this end, we first developed a novel algorithm to calculate the largest rectangular parallelepiped that can be placed inside a block and then defined a regularity factor (α) and a quarry block shape factor (q) that enable the geometric quality of the block to be assessed more accurately than currently possible. The sensitivity analysis of these factors showed that the change in angle relative to the change in spacing has the greater effect on the geometric quality. The proposed factors displayed a good performance in a comparison analysis of four sites of the Dareh Bokhari travertine quarry complex located in Mahallat, Markazi province, Iran. Based on the results, blocks at sites 2 and 4 have the lowest and the highest geometric quality, respectively, which is in accordance with the operational conditions at the respective sites. Moreover, comparison of the values of factor q obtained from applying various cutting planes indicated that to maximally increase block production capacity, the current cutting direction at site 4 should be adjusted 33° eastward.

     

3D meshless simulation of laser ray deviation under thermal lensing effect

In this study, one of the most important destructive effects in end‐pumped Nd:YAG laser, that is, thermal lensing is analyzed. Different partial differential equations, supplemented by suitable boundary conditions, are solved and joined to illustrate the fluctuations in laser Transverse Electromagnetic (TEM) mode. Because of no analytic demonstration of this effect, an efficient meshless method known as radial point interpolation meshless method (RPIM) is used to simulate the problem divided into two two‐dimensional cases, that is, xz and yz planes so as to be graphically understandable. The results are in good agreement with measurement reports, and the RPIM shows better accuracy than FEM. Copyright © 2015 John Wiley & Sons, Ltd.     

Application of fractal dimensions to study the structure of flocs formed in lime softening process

The use of fractal dimensions to study the internal structure and settling of flocs formed in lime softening process was investigated. Fractal dimensions of flocs were measured directly on floc images and indirectly from their settling velocity. An optical microscope with a motorized stage was used to measure the fractal dimensions of lime softening flocs directly on their images in 2 and 3D space. The directly determined fractal dimensions of the lime softening flocs were 1.11-1.25 for floc boundary, 1.82-1.99 for cross-sectional area and 2.6-2.99 for floc volume. The fractal dimension determined indirectly from the flocs settling rates was 1.87 that was different from the 3D fractal dimension determined directly on floc images. This discrepancy is due to the following incorrect assumptions used for fractal dimensions determined from floc settling rates: linear relationship between square settling velocity and floc size (Stokes’ Law), Euclidean relationship between floc size and volume, constant fractal dimensions and one primary particle size describing entire population of flocs. Floc settling model incorporating variable floc fractal dimensions as well as variable primary particle size was found to describe the settling velocity of large (>50 μm) lime softening flocs better than Stokes’ Law. Settling velocities of smaller flocs (<50 μm) could still be quite well predicted by Stokes’ Law. The variation of fractal dimensions with lime floc size in this study indicated that two mechanisms are involved in the formation of these flocs: cluster-cluster aggregation for small flocs (<50 μm) and diffusion-limited aggregation for large flocs (>50 μm). Therefore, the relationship between the floc fractal dimension and floc size appears to be determined by floc formation mechanisms.     

Identification of the Sex Pheromone of Sesamia cretica Lederer

By using solid phase micro-extraction and gas chromatography–mass spectrometry analyses, a sex pheromone blend for the stem borer, Sesamia cretica Lederer (Lepidoptera, Noctuidae), was identified as consisting of (Z)-9-tetradecen-1-ol (80%), (Z)-9-tetradecen-1-yl acetate (10%), and (Z)-11-hexadecen-1-ol (10%). The first two components had previously been discovered as attractants for S. cretica in field tests, but had not been identified in the female’s sex pheromone gland. A field-trapping trial showed that the three-component blend gave the highest catches of male S. cretica. This blend, in a sticky trap, was used to monitor a population of S. cretica in Iran, allowing the seasonal flight activity of this insect to be compared with that of a sympatric population of S. nonagrioides. The role of pheromones in the reproductive isolation of these species is discussed.     

Surface modification and preparation of nanofiltration membrane from polyethersulfone/polyimide blend—Use of a new material (polyethyleneglycol‐triazine)

Blends of polyethersulfone/polyimide (PES/PI) were prepared by dissolving in dimethylformamide/dioxane (DMF/DO) to manufacture nanofiltration membranes by using polyvinylpirrolidone (PVP) as a pore former. The membrane modification was carried out by adding ethylenediamine (EDA) to open the imide group ring of PI and by using polyethyleneglycol (PEG)‐triazine, as a new modifier material, that was produced in the laboratory. This modification involves the formation of a covalence ‐C‐N‐ bound between PEG‐triazine and amine groups (according to addition‐elimination reactions) at different temperatures. After functionalizing the membranes, diethanolamine (DA) was utilized as a hydrophilic modifier to change the membranes properties. SEM, AFM, FTIR‐ATR, EDS (X‐ray analysis) and contact angle tests were carried out to characterize modified membranes. The hydrophilicity of PES/PI membranes was improved by modification. An increase in pure water flux (up to 195 kg/m² h) and a decline in NaCl rejection (from 25 to 16%) are largely influenced by diminishing the PES/PI ratio in L₁‐L₅ membranes (Category 1). In L₆, L₇, and L₈ membranes (Category 2), by introducing PEG‐triazine into the membrane recipe, salt rejection increased from 75 to 80%. Addition of DA further enhances the salt rejection up to 93%. Fluxes were approximately similar for membranes in Category 2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The effect of magnesium content on in vitro bioactivity,biological behavior and antibacterial activity of sol–gel derived 58S bioactive glass

Bioactive glasses (BGs) have a great potential for bone replacement and regeneration in bone tissue engineering applications. In this research, first, sol–gel derived magnesium substituted 58?S BGs (MBGs) series composed of 60SiO₂–4P₂O₅-(36-x) CaO- xMgO, (x = 0; 1; 3; 5; 8 and 10?mol.%) were synthesized and stabilized at 700?°C to eliminate the nitrates and prevent the crystallization of MBGs. MgO was substituted for CaO in the BG formula up to 10?mol% and the effect of Mg concentration on in vitro bioactivity and cellular properties of the MBGs were investigated by immersing them in simulated body fluid (SBF) followed by structural characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The effects Mg on proliferation and differentiation of osteoblastic MC3T3-E1 cells were also evaluated by 3-(4,5dimethylthiazol-2-yl)??2,5-diphenyltetrazolium bromide (MTT) and alkaline phosphate (ALP) activity.Results revealed that magnesium-substituted 58?S BG with 5?mol% MgO (BG-5) had the highest formation rate of hydroxyapatite (HA) while substitution of 8?mol% and10 mol% MgO (BG-8 and BG-10) lowered the bioactivity. MTT and ALP results confirmed that the substitution of the MgO up to 5?mol% increased both proliferation and differentiation of MC3T3-E1 cells, while more substitution had a negative effect and resulted in a decrease of proliferation and differentiation in BG-8 and BG-10. The result of antibacterial test showed that MBGs exhibited antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Taken together, results suggest that, among all the synthesized MBGs, sample BG-5 is a promising candidate as multifunctional biomaterial for bone tissue engineering with maximum cell proliferation and ALP activity, good bioactivity and high antibacterial efficiency against MRSA bacteria. Eventually, the BG-5 is suggested to be used in segmental defects in rat model in vivo.     

Impact of functionalized SiC nano-whisker on the flux pinning ability and superconductor features of Bi-2223 ceramics

In this study, we investigated the role of silicon carbide nano-whisker (SiC-NW) as new pinning center on the microstructure, magnetic and flux pinning properties of (BiPb)₂Sr₂Ca₂Cu₃O_10+θ (Bi-2223) superconductors prepared by the sol-gel method. The surface of the nano-whiskers was modified with Azobisisobutyronitrile (AIBN) to improve their dispersions. The grafting of AIBN on the surface of SiC-NW was studied with FTIR. According to the field emission scanning electron microscope, X-ray diffraction, and magnetization measurements, we found an enhancement in the superconducting features of the specimen with the addition of SiC-NW up to 0.2 wt%. The microstructure of the samples showed randomly oriented plate-like grains. The connectivity and alignment of the grains slightly reduced with the increase in the SiC-NW concentration. Based on the magnetic measurement of the synthesized samples, an improvement of magnetization, pinning force ability and the critical current density (Jc) was observed for the 0.2 SiC-NW.     

Integral sliding mode control for nonlinear damped model of arch microbeams

Microsystem Technologies - In this paper, a second order integral sliding mode controller (SMC) and a two-dimensional integral sliding mode controller are designed for a nonlinear damped model of...     

CFD analysis of flow field in square cyclones

In this study, computational fluid dynamic method is used to predict and evaluate the flow field inside a square cyclone. The flow field is calculated using 3D Reynolds-averaged Naveir-Stokes equations. The Reynolds stress transport model (RSTM) is used to simulate the Reynolds stresses. The Eulerian-Lagrangian computational procedure is implemented to predict particle trajectory in the cyclone. The Newton's second law is used to study the particle trajectory with modeling the drag and gravity forces acting on the particles. The velocity fluctuations are simulated using the discrete random walk (DRW). Two square cyclones which have different geometries are studied. The cyclones are simulated at different flow rates. The details of the flow field are studied in the cyclones and the effect of varying the flow rates is observed. Tangential velocity is investigated in different sections inside the square cyclone. Contour of pressure and turbulence intensity is shown for different inlet velocities inside the cyclones. It is observed that different geometries, also different inlet velocities, could affect on the pressure drop. The collection efficiency and the flow patterns obtained numerically are compared with the experimental data and good agreement is observed.