The Quantitative Effect of Drying on the Surface Color Change of Reaction Woods: Spruce Compression Wood (Picea abies L.) and Poplar Tension Wood (Populus nigra L.)

The surface color change of compression wood in spruce (Picea abies L.) and tension wood in poplar (Populus nigra L.) due to drying was investigated using CIE LAB and CIELCh colorimetry techniques. The results showed that the compression wood was lighter, yellower, less red, and more statured in color with a deeper hue after drying. Similar changes were also seen with the tension wood, except that it was less yellow and less statured in the dry condition. The color change (ΔE) of compression wood was found to be more remarkable than that of tension wood. Overall, the difference in the colorimetric parameters between the reaction woods and their corresponding normal woods was less significant after drying.     

A replenishment policy for perishable products with non-linear holding cost under stochastic supply lead time

The development and application of inventory models for deteriorating items is one of the main concerns of subject matter experts. The inventory models developed in this field have focused mainly on supply chains under the assumption of constant lead time. In this study, we develop an inventory model for a main class of deteriorating items, namely perishable products, under stochastic lead time assumption. The inventory system is modeled as a continuous review system (r, Q). Demand rate per unit time is assumed to be constant over an infinite planning horizon and the shortages could be backordered completely. For modeling the deterioration process, a non-linear holding cost is considered. Taking into account the stochastic lead time as well as a non-linear holding cost makes the mathematical model more complicated. We customize the proposed model for a uniform distribution function that could be tractable to solve optimally by means of an exact approach. We then solve an example taken from the literature to demonstrate the applicability and effectiveness of the proposed model. Finally, by doing several sensitivity analyses for the key parameters of the model, some managerial insights are proposed.     

The effect of Si content,firing temperature,and urea additive on the properties of nitride-bonded SiC refractories

The microstructure-properties relationship of nitride-bonded SiC refractories has been studied in the presence of Si and urea additives. The samples were prepared by mixing, shaping, and firing at 1450 to 1600°C in a controlled atmosphere. Physical properties were evaluated by measuring density, porosity, and cold crushing strength (CCS). XRD, SEM, and TEM were employed to study the phase and microstructural evolution. The increase of Si enhanced the bond formation, which contributed to density and strength improvement. The firing temperature had the same effect up to 1550°C. At 1600°C, however, the density and CCS decreased, which were attributed to nitride phase decomposition. The urea addition improved the mechanical properties and increased the depth of nitridation. __________ Translated from Novye Ogneupory, No. 10, pp. 68–72, October 2007.     

GA-ILP Method for Optimization of Water Distribution Networks

Optimization of water distribution networks has been of central importance for recent decades. Genetic Algorithms (GA) are the most famous metaheuristics widely used for this purpose with great success. However, the fact that GA basically requires a large number of computations, has led to investigate for faster solvers. In this research, a new approach is proposed in which a simple GA is linked with the Integer-Linear Programming (ILP) method resulting in a hybrid optimization scheme. Using the mathematical method of ILP, the search space is significantly reduced thereby a limited number of evaluations are required to achieve a good solution. The approach is applied to two benchmark pipe-networks in order to show its ability in terms of accuracy and speed. The results are then compared with the previous works. The obtained results indicate that the proposed model is computationally efficient, like classic methods, while is still very promising in finding the global optimum like the nature-inspired metaheuristics.     

Fe3 O4 /Ag nanocomposite biosynthesised using Spirulina platensis extract and its enhanced anticancer efficiency

In this work, the authors investigated the apoptotic activities of Fe₃ O₄ /Ag nanocomposite biosynthesised by Spirulina platensis extract against MCF‐7 (human breast cancer cells). The physico‐chemical properties of prepared Fe₃ O₄ /Ag nanocomposite were studied by different spectroscopic methods. To evaluate the in vitro cytotoxic effect, MCF‐7 cells were treated with different concentrations of Fe₃ O₄ /Ag nanocomposite and examined by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide (MTT) assay. Moreover, apoptotic effects were also studied by Hoechst 33258 staining, caspase 3 activation assays, and annexin V‐fluorescein isothiocyanate (FITC) and propidium iodide staining. Microscopic observations of Fe₃ O₄ /Ag nanocomposites indicated approximately spherical shape and small particles in the size range of about 30–50 nm. The MTT assay result revealed that the Fe₃ O₄ /Ag nanocomposite causes a dose‐dependent cell proliferation reduction in MCF‐7 cells (IC₅₀  = 135 μg/ml). Regarding to the Annexin V/PI staining result, the increase percentage of apoptotic cells (28.09%) was detected as compared to untreated cells. According to the caspase assay, Fe₃ O₄ /Ag nanocomposite enhances caspase 3 level. Furthermore, in vitro anti‐cancer activity of the nanocomposite was performed by Hoechst 33258 staining method. The proposed data suggest that Fe₃ O₄ /Ag nanocomposite may be an effective agent for the inhibition of breast cancer cells at in vitro level.Inspec keywords: nanomedicine, nanocomposites, toxicology, cancer, drug delivery systems, nanofabrication, cellular biophysics, nanoparticlesOther keywords: MCF‐7 cells, 5‐diphenyl‐tetrazolium, apoptotic effects, propidium iodide staining, dose‐dependent cell proliferation reduction, apoptotic cells, untreated cells, nanocomposite, Hoechst 33258 staining method, human breast cancer cells, physico‐chemical properties, spectroscopic methods, in vitro cytotoxic effect, in vitro anticancer activity, biosynthesis, caspase 3 activation assays, annexin V‐fluorescein isothiocyanate, FITC, Fe₃ O₄ ‐Ag     

Wear of MgO-C Refractories in EBT Type Furnaces Experienced at Iranian Mobarakeh Steel Plant

Mobarakeh Steel Company produces 3 million tons ofsteel annually with eight 180 tons EBT furnaces. Differ-ent types of magnesia-carbon refractories have been em-ployed at slagline during last 5 years. In the present studythe wear and corrosion of MgO-C refractories of these fur-naces have been studied via post-mortem analysis of usedbricks and the observation of operational effects. Laborato-ry corrosion tests were also arranged to investigate the effectof slag chemistry and the mechanism of chemical corro-sion. Characterization of different magnesia-carbon bricksclarified that the crystal size, type and chemistry of mag-     

Preparation of a novel biodegradable nanocomposite scaffold based on poly (3-hydroxybutyrate)/bioglass nanoparticles for bone tissue engineering

One of the most important challenges in composite scaffolds is pore architecture. In this study, poly (3-hydroxybutyrate) with 10% bioglass nanoparticles was prepared by the salt leaching processing technique, as a nanocomposite scaffold. The scaffolds were characterized by SEM, FTIR and DTA. The SEM images demonstrated uniformed porosities of appropriate sizes (about 250–300 μm) which are interconnected. Furthermore, higher magnification SEM images showed that the scaffold possesses less agglomeration and has rough surfaces that may improve cell attachment. In addition, the FTIR and DTA results showed favorable interaction between polymer and bioglass nanoparticles which improved interfaces in the samples. Moreover, the porosity of the scaffold was assessed, and the results demonstrated that the scaffold has uniform and high porosity in its structure (about 84%). Finally it can be concluded that this scaffold has acceptable porosity and morphologic character paving the way for further studies to be conducted from the perspective of bone tissue engineering.     

Zr (IV)-ninhydrin supported MCM-41 and MCM-48 as novel nanoreactor catalysts for the oxidation of sulfides to sulfoxides and thiols to disulfides

Modification of MCM-41 and MCM-48 mesoporous materials with bonded aminosilane species, Schiff base preparation by ninhydrin and finally complexation with zirconium, has attracted much attention in order to design catalyst with advanced applications in the oxidation of sulfides to sulfoxides and thiols to disulfides in the presence of hydrogen peroxide. In all oxidation of sulfides to sulfoxids 0.4 mL H₂O₂ used as oxidant in the presence of Zr(IV)-ninhydrin supported MCM-41 (0.01 g) or Zr(IV)-ninhydrin supported MCM-48 (0.005 g) at room temperature and solvent-free condition. Also the best conditions for oxidation of thiols to disulfides with 0.4 mL H₂O₂ were 0.005 g Zr(IV)-ninhydrin supported MCM-41 or Zr(IV)-ninhydrin supported MCM-48 at room temperature and in ethanol. These catalysts are characterized by SEM, XRD, TGA, FT-IR, EDS, ICP and BET analysis. Also the Turn over frequency (TOF) and Turn over number (TON) of catalysts are calculated. Obtained results by these heterogeneous catalysts revealed several advantages including short reaction times, simple workup, easy isolation and reusability.