Effect of metal coating of reinforcements on the microstructure and mechanical properties of Al-Al2O3 nanocomposites

The effects of various methods of reinforcement modification on the microstructure and mechanical properties of Al–Al₂O₃ nanocomposites were investigated. Alumina nanoparticles were modified by electroless deposition of Cu, Ni and Co. Subsequently, aluminium matrix nanocomposites reinforced with uncoated and coated nanoparticles were produced by the stir casting method. The results of microstructural analysis showed improved wettability of coated nanoparticles in the molten aluminium alloy. Furthermore, coated nanoparticles exhibited a more desirable interface with the matrix and were homogenously distributed within it. The mechanical properties of the nanocomposites were improving significantly when coated nanoparticles were used as reinforcements. Among the reinforcement modification methods, Ni-coating was recognised as being more effective for improving the mechanical properties of Al–Al₂O₃ nanocomposites.     

Synthesis and Characterization of Electro-Crystallized Alumina Nanoparticles and Investigation of Their Application in Removal of Cobalt and Cadmium from Seimareh and Karoon Rivers in Iran

Al₂O₃ nanoparticles were successfully synthesized in an electrolytic cell containing two Al sheets as electrodes and an aqueous solution in the presence of an amine. To measure the effect of growth parameters on the properties of alumina nanoparticles, different samples were synthesized under different voltages (5–25 V), electrolyte concentration (0.02–0.1 M) and growth temperatures (10–60°C). X-ray diffraction patterns clearly approved the formation of the Al₂O₃ phase with cubic structure after annealing at 600°C for 2 h, and no sign of impurities was observed. SEM images showed that the particles are quasi-spherical and their mean size ranged from 7 to 270 nm depending on the growth conditions. The ultraviolet–visible results showed that the alumina nanoparticles mainly disperse rather than absorb light. The photoluminescence emission spectrum of nanoparticles showed an original peak at 395 nm, which is related to the electron transition between the levels and the photon emission. The removal of cobalt and cadmium from experimentally polluted water and the Seimareh and Karoon Rivers in Iran has been investigated. The water treatments were studied in an electrochemical cell with polluted water as the electrolyte, and by mixing the alumina nanoparticles with polluted water in a shaker. The results of atomic absorption spectroscopy showed that it is possible to remove about 100% of cadmium from the Seimareh and Karoon rivers. Also, by mixing the alumina nanoparticles with polluted water in a shaker, about 37.77% and 91.06% of cobalt were removed from the Seimareh and Karoon rivers, respectively.     

An improved bat optimization algorithm to solve the tasks scheduling problem in open shop

Neural Computing and Applications - The open shop scheduling problem involves a set of activities that should be run on a limited set of machines. The purpose of scheduling open shops problem is to...     

Electrosynthesis and physioelectrochemical properties of poly tyramine electroactive film in the presence of the surfactant: Comparable study

We describe in detail the advantages of a novel method of electrochemical preparation of poly tyramine (PT), based on the ability of anionic surfactants to form micelles in aqueous media. We demonstrate that the electropolymerisation process carried out in the presence of sodium dodecyl sulfate (SDS) at an oxidation potential lower than in an aqueous media yields better organized PT films. Theoretical calculations for tyramine (Ty) polymerization were carried out at density functional theory (DFT) level using the 6-31G(d,p) basis set. The improved physicochemical and structural properties of PT obtained in these conditions related to the electrocatalytic effect of SDS and change fractal dimension of the film. With respect to Ni-PT/G, Ni-SDS-PT/G electrode shows a higher catalytic performance for the electrocatalytic oxidation of methanol.     

Ionizability and Bioaccessibility of Externally Added Iron in Legumes and Their Water Soluble Protein Fractions

The present investigation focused on determining ionizable iron from legumes, their water soluble protein fraction (albumin), and enzyme hydrolyzed albumin in the presence and absence of external iron. The legumes chosen were decorticated chick pea (Cicer arietinum), green gram (Phaseolus aureus Roxb), lentil (Lens esculenta), and defatted soy (Glycine max merr). Total iron, protein, and ionizable iron were estimated in samples with and without added iron (500 and 1000 μg/g of protein). Protein content of legumes ranged between 22.5–28.5 g/100 g for all except soy (59.6 g/100 g); that of albumin fractions and enzyme hydrolyzed albumin was 82.5–89.1 and 82.5–94.1 g/100 g, respectively. Total iron contents were 5.6, 8.13, 6.25, and 15 mg/100 g for chick pea, green gram, lentil, and soy, respectively, whereas ionizable iron ranged between 0.625–0.813 μg/100 g. On adding external iron, the ionizable iron increased to 719–1445 μg (500 μg/g protein) and 1219–1545 μg (1000 μg/g protein). In albumin fraction of legume, the ionizable iron range (as % of total iron) observed were 28.7–68.0 (500 μg added iron) and 25.0–37.3 (1000 μg added iron). On enzyme hydrolysis of albumin, these ranges were between 256–464 μg/g protein for both levels of added iron. Overall results indicate that ionizable iron from legumes was very low. On adding iron an increase could be seen; however, it was not proportionate to added levels. Better ionizability was observed at a lower level of addition than at higher levels in all samples indicating existence of an optimum level of iron for absorption.     

Antioxidant Effects of Grape Pomace on the Quality of Silver Carp (Hypophthalmichthys molitrix) Fillets During Refrigerated Storage

This study aimed to determine the phenolic content and antioxidant effect of grape pomace extract on silver carp fillets during refrigerated storage. Total phenolic content of grape pomace extract was quantified by colorimetric methods. Silver carp samples were treated with 0, 2, and 4% of grape pomace extract (g extract/100 g flesh) and stored 15 days in a refrigerator (4°C). Changes in pH, peroxide value, thiobarbituric acid, and heme iron at 0, 3, 6, 9, 12, and 15 days of storage were investigated. Results showed that the values of pH, peroxide value, and thiobarbituric acid increased and iron levels decreased in all treatments during storage (p < 0.05). The phenolic contents were generally much more influenced by the quality parameters treated compared to the control. The addition of grape pomace extract delayed lipid oxidation in silver carp fillet considerably during refrigerated storage. These results suggested that grape pomace extract has the potential to be used as a natural antioxidant.     

Governance lessons from the experience of telecentres in Kerala

Telecentres are seen as essential components of governance reform in the international development community and great optimism has been expressed in academic and policy literature regarding their developmental potential. The scope of our paper is to move beyond the confines of conventional governance ideology and to propose a broader conceptual lens through which to study the complexity of issues that need to be addressed in order to make telecentres sustainable. Following several years of experience with these projects, evidence shows that their long-term survival depends upon how interactions are managed between a host of players including the government, private entrepreneurs, international donors, telecommunications suppliers, local companies, civil society organisations and individual community members. This paper proposes that the sociology of governance approach is highly relevant for a study of telecentre sustainability. This theoretical approach is used as a lens through which to investigate issues regarding the sustainability of the Akshaya telecentre project in Kerala in terms of interactions between various groups of players. We adopt a practical reflexive-interpretive methodological approach to encourage the development and reshaping of theoretical ideas about governance through our empirical data. We identify five critical issues currently affecting sustainability of the Akshaya project focusing on how relations and exchanges have been managed over time. Our analysis has important theoretical and policy implications for the Akshaya project and more generally for telecentre initiatives launched as part of governance reform in developing countries.     

Design and optimization of alginate−chitosan−pluronic nanoparticles as a novel meloxicam drug delivery system

The inflammation and pain associated with osteoarthritis are treated with nonsteroidal anti‐inflammatory drugs (NSAIDs). This treatment is accompanied by several side effects; therefore local intra articular (IA) NSAID injection can be more efficient and safe than systemic administration or topical use. In this study, alginate?chitosan?pluronic nanoparticles were considered as a new vehicle for IA meloxicam delivery. These novel nanoparticles were prepared using an ionotropic gelation method and were optimized for variables such as alginate to chitosan mass ratio, pluronic concentration, and meloxicam concentration using a 3‐factor in 3‐level Box‐Behnken design. To optimize the formulation, the dependent variables considered were particle size, zeta potential, entrapment efficiency, and mean dissolution time (MDT). The nanoparticles morphology was characterized by FESEM and AFM. The potential interactions of the drug‐polymers were investigated by ATR‐FTIR and DSC, and the delivery profile of meloxicam from the nanoparticles was obtained. The average particle size of the optimized nanoparticles was 283 nm, the zeta potential was ?16.9 mV, the meloxicam entrapment efficiency was 55%, and the MDT was 8.9 hours. The cumulative released meloxicam amount from the composite nanoparticles was 85% at pH 7.4 within 96 h. The release profile showed an initial burst release followed by a sustained release phase. The release mechanism was non‐Fickian diffusion. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42241.     

Representing and reasoning about preferences in requirements engineering

The priorities that stakeholders associate with requirements may vary from stakeholder to stakeholder and from one situation to the next. Differing priorities, in turn, imply different design decisions for the system to be. While elicitation of requirement priorities is a well-studied activity, modeling and reasoning with prioritization has not enjoyed equal attention. In this paper, we address this problem by extending a state-of-the-art goal modeling notation to support the representation of preference (??nice-to-have??) requirements. In our extension, preference goals are distinguished from mandatory ones. Then, quantitative prioritizations of the former are constructed and used as criteria for evaluating alternative ways to achieve the latter. To generate solutions, an existing preference-based planner is utilized to efficiently search for alternatives that best satisfy a given set of mandatory and preferred requirements. With such a planning tool, analysts can acquire a better understanding of the impact of high-level stakeholder preferences on low-level design decisions.     

Effect of Process Variables on the Grain Size and Crystallographic Texture of Hot-Dip Galvanized Coatings

A galvanizing simulator was used to determine the effect of galvanizing bath antimony (Sb) content, substrate surface roughness, and cooling rate on the microstructural development of metallic zinc coatings. Substrate surface roughness was varied through the use of relatively rough hot-rolled and relatively smooth bright-rolled steels, cooling rates were varied from 0.1 to 10 K/s, and bulk bath Sb levels were varied from 0 to 0.1 wt pct. In general, it was found that increasing bath Sb content resulted in coatings with a larger grain size and strongly promoted the development of coatings with the close-packed {0002} basal plane parallel to the substrate surface. Increasing substrate surface roughness tended to decrease the coating grain size and promoted a more random coating crystallographic texture, except in the case of the highest Sb content bath (0.1 wt pct Sb), where substrate roughness had no significant effect on grain size except at higher cooling rates (10 K/s). Increased cooling rates tended to decrease the coating grain size and promote the {0002} basal orientation. Calculations showed that increasing the bath Sb content from 0 to 0.1 wt pct Sb increased the dendrite tip growth velocity from 0.06 to 0.11 cm/s by decreasing the solid–liquid interface surface energy from 0.77 to 0.45 J/m². Increased dendrite tip velocity only partially explains the formation of larger zinc grains at higher Sb levels. It was also found that the classic nucleation theory cannot completely explain the present experimental observations, particularly the effect of increasing the bath Sb, where the classical theory predicts increased nucleation and a finer grain size. In this case, the “poisoning” theory of nucleation sites by segregated Sb may provide a partial explanation. However, any analysis is greatly hampered by the lack of fundamental thermodynamic information such as partition coefficients and surface energies and by a lack of fundamental structural studies. Overall, it was concluded that the fundamental mechanisms behind the microstructural development of solidified metallic zinc coatings have yet to be completely elucidated and require further investigation.