Alginate@Layered Silicate Composite Beads: Dye Elimination,Box–Behnken Design Optimization and Antibacterial Property

Journal of Inorganic and Organometallic Polymers and Materials - The discharge of industrial waste comprising organic pollutants into aquatic environment induces numerous health risks. Crosslinked...     

Effect of processing parameters on compression molded PMR-15/C3K composites

The consolidation and curing history during the processing of composite materials affects the final properties of a part in various inter-related ways. In order to improve the quality of composites, these process-property relations must be understood in detail. Using a computer-controlled compression molding and data acquisition system, the processing of PMR-15/C3k composites has been investigated. The process parameters considered were the pressure, the time at which it was applied and the crosslinking temperature. Parts were tested for inter-laminar shear strength and flexural modulus, and measurements were made for void content and thickness. Full compaction strength, optimum compaction strength and void sensitivity factor have been defined.     

Effect of pH at time of salting on the functional properties of pre-rigor beef

The functional properties of thawed pre-rigor beef that had been minced and salted or not salted when its pH value reached 6.8, 6.6, 6.4, 6.2 and 6.0, then immediately frozen, were determined. The mince samples were used to manufacture a finely comminuted sausage batter. Presalting before frozen storage resulted in higher (p < 0.05) thawed mince pH, and batter cook yield and shear strain, and lower (p < 0.05) mince salt soluble proteins, thaw drip and Hunter L^* and b^* values and batter shear stress than unsalted controls. The pre-rigor pH at time of salting/mincing affected (p < 0.05) thaw drip (unsalted mince only), Hunter L^* and b^* values and shear stress. Shear stress tended to increase (p < 0.01) and Hunter L^* (p < 0.05) and b^* (p < 0.01) values tended to decrease with fall in pre-rigor salting pH. No interaction (p > 0.05) between salting and pre-rigor pH at time of salting was observed.     

Rapid homogeneous esterification of cellulose extracted from Posidonia induced by microwave irradiation

In this article, we report on the synthesis of cellulose esters by the reaction of cellulose and some cyclic anhydrides, such as succinic, maleic, and phthalic anhydrides. For this, an esterification method was finalized. Indeed, cellulose extracted from Posidonia biomass was first solubilized in the solvent system lithium chloride (LiCl)/N,N‐dimethylacetamide and then esterified by cyclic anhydride in the presence of catalysts such as N,N‐dimethyl‐4‐aminopyridine, tripropylamine, tributylamine, and calcium carbonate. This method was fast and reproducible with the LiCl system as a solvent and with an efficient activation by controlled microwave power. In this way, the reaction time was reduced from several hours to just a few minutes. The reaction products were characterized by IR and solid‐state cross‐polarization/magic angle spinning ¹³C‐NMR spectroscopy. The degree of substitution (DS) and the grafted ester group content of the different products were obtained by alkali saponification followed by titration of the excess alkali. Two activation methods were compared, and the results show that the application of classical heating gave less successful results than those obtained by microwave activation. Indeed, with microwave activation, a higher DS (2.25) was obtained after 10 min. However, with classical heating, a value of DS equal to 1.2 was obtained after 12 h. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Melting metal powder particles in an inductively coupled r.f. plasma torch

A numerical model is developed for the prediction of melting metal powder particles in an inductively coupled r.f. plasma torch. The model is developed for dilute spray conditions where the gas phase flow is not affected by the loading condition. The governing equation for the gas phase flow contains the source terms from the electromagnetic field. The theoretical calculations have shown that particle thermal history and its velocity are greatly affected by the plasma operating conditions (i.e., carrier gas flow rate, injector location, and power level,etc.). Without the proper control of particle trajectories, particles may bounce around the fireball and exit the torch as unmelted or resolidified solid particles. With the insertion of an injector or injecting particles with a high carrier gas flow rate, the predictions show that even relatively small size particles can be directed into the fireball and maintained in the molten state before they impact on the substrate. Consequently, more uniform and dense deposits can be achieved.     

Preclinical evaluation of <Superscript>99<Emphasis Type="Italic">m</Emphasis> </Superscript>Tc-histidine as a possible tumor imaging agent

Radiolabeling of histidine (Hist), an essential amino acid, with ^99mTc was performed. The radiochemical yield higher than 95% was achieved with stannous chloride as a reducing agent. Factors affecting the radiochemical yield (histidine amount, stannous chloride amount, reaction time, pH of the reaction mixture) were studied in detail, and the reaction conditions were optimized. In vitro stability of the radiolabeled complex was checked, and it was found to be stable for up to 6 h. ^99mTc-Hist was injected intravenously into normal and tumor-bearing mice. Biodistribution studies revealed that the ^99mTc-Hist uptake in tumor sites was 10 and 16% ID/g in ascites and 7 and 9.2% ID/g in thigh solid tumor at 60 and 120 min post injection, respectively. The amount of ^99mTc-Hist in ascites and solid tumor increased with time and then decreased slowly. Thus, ^99mTc-Hist can be used as a potential agent for imaging tumor sites.     

Generalized thermo-microstretch elastic medium with temperature dependent properties for different theories

A general model of the equations of generalized thermo–microstretch for a homogeneous isotropic elastic half–space is given. The modulus of elasticity is taken as a linear function of reference temperature. The formulation is applied to generalized thermoelasticity theories, the Lord–?hulman and Green–Lindsay theories, as well as the classical dynamical coupled theory. The normal mode analysis is used to obtain the exact expressions for the displacement components, force stresses, temperature, couple stresses and microstress distribution. The variations of the considered variables through the horizontal distance are illustrated graphically. A comparison is made with the results predicted by the three theories in case of temperature–independent modulus of elasticity.     

Reaction of chrysotile asbestos with triphenylmethane dyes

Triphenylmethane dyes react at ambient conditions with chrysotile asbestos to form homogeneously coloured fibres. Formation of the chelates on the fibre varies: for Basic Fuchsin, Malachite Green and Methyl Blue equilibrium is reached in 1 h, the concentration on the fibre is 1% to 2.4%, and increases slightly on boiling. For Brilliant Blue R, Crystal Violet, and Methyl Violet equilibrium is reached after 16 to 24 h, the concentration on the fibre is 8% to 10%, and increases greatly on boiling reaching 10% to 31%. No precipitates were observed on the coloured fibre under the scanning electron microscope indicating a chelate formation. This was also supported by X-ray diffraction and infrared analysis.     

Optimization approaches and climates investigations in NZEB—A review

The conception of net zero energy buildings (NZEB) has been introduced to limit energy consumption and pollution emissions in buildings. Classification of NZEB is based on renewable energy (RE) supply options, energy measurement process, RE-sources location, and balances whether are energetic or exergetic. In general, it is traditionally agreed that there are three main steps to reach the NZEB performance, starting through the use of passive strategies, energy efficient technologies, and then RE generation systems. Then, these three steps could be accompanied with the smart integration of advanced efficient energy technologies. A state of the art shows that the main ZEB studies are related to: energy savings, reduce electric bills, energy independence, pollution reduction, and occupants comfort, in addition, others are more interested in the aesthetic aspect by combining modern technologies with innovations to achieve high energy and sustainability performance. Building optimization is a promising technique to evaluate NZEB design choices; it has been adopted to choose the perfect solution to reach the zero energy performance through the optimization of an objective function related to energy (thermal loads, RE generation, energy savings) and/or environment (CO₂ emissions) and/or economy (life-cycle cost (LCC), net-present value (NPV), investment cost). This paper starts by presenting the global energetic and pollution challenges the world faces. Moreover, it shows, to the best to the author’s knowledge, the existing NZEB definitions and the corresponding case studies investigated in 8 different climatic zones (humid continental, humid subtropical, Mediterranean, moderate continental, moderate continental, marine west coast, tropical, semi-arid and hot), the paper also focus on the importance to treat each climate separately. Even in the same country, two or more climates may co-exist. NZEBs drawbacks are also presented. Furthermore, different optimization problems are reviewed in the last section. Building energy optimization methods are employed to obtain the ideal solution for specific objective functions which are either related to energy, and/or environment and/or economy. Optimization variables are distributed between passive and/or RE generation systems. Finally, a table summarizing the most commonly used electric and thermal RE applications which yield to the zero energy balance in each climate, as well as three flowcharts are presented to summarize the whole three-stage procedure, to reach NZEB, starting from building designing, passing through the optimization procedure, and lastly categorizing the zero energy balance.     

Distributed address auto configuration protocol for Manet networks

In heterogeneous network environments, the network connections of a multi-homed device may have significant bandwidth differential. For a multi-homed transmission protocol designed for network failure tolerance, such as SCTP, path selection algorithms for data transmission drastically affect performance. This article studies the effect of path bandwidth differential on the performance of retransmission strategies in multi-homing environments. It identifies that fast retransmission on an alternate path may cause receive buffer blocking when path bandwidth differential is significant and the receive buffer is limited. A theoretical model is proposed for selecting retransmission path during the fast retransmission phase, based on receive buffer and path conditions. From these observations and analysis results, this article proposes that path selection strategies for transmitting new data and retransmitted data should be decoupled. A new path selection scheme is proposed and evaluated through SCTP simulations.