Multi-objective optimization of industrial styrene reactor: Adiabatic and pseudo-isothermal operation

Multi-objective differential evolution (MODE) is used to optimize an industrial styrene reactor considering productivity, selectivity and yield as the main objectives. Two reactor configurations (single bed adiabatic operation and steam injected pseudo-isothermal operation) and four combinations of objectives consisting of 5 and 7 variables respectively are considered. Pareto optimal solutions are obtained for all combinations of objective functions for both the configurations. The results are compared with those reported in the literature and an industrial operating point. For all the cases considered, MODE is able to give a Pareto front better (in terms of wider range and a better spread) than that obtained using NSGA for both the configurations. Steam injected reactor configuration is better than the adiabatic reactor configuration in terms of performance. The Pareto optimal solutions obtained from such studies provide a wide range of optimal operating conditions from which an appropriate operating point can be selected based on the requirements of the decision maker.     

Synthesis and anion-sensing property of a family of Ru(II)-based receptors containing functionalized polypyridine as binding site

A family of fluoroionophores have been synthesized incorporating Ru(II)-bipyridine moiety as fluorogenic unit and amino/benzenesulphonamido functionalized 1,10-phenanthroline moiety, attached to Ru(II), as binding sites. Two of the ligands and one of the complexes have been characterized crystallographically. Anion recognition property, studied by luminescence, UV–vis and ¹H NMR spectroscopy, with a large number of anions exhibit strong complexation with F^?, H₂PO₄^? and AcO^?. Binding constants have been determined from luminescence titration and ¹H NMR study gave insight about binding site of anions. Bidentate chelating nature of the H₂PO₄^? and AcO^? anions and steric crowding created by benzenesulphonamide moiety has significantly influenced binding constants and selectivity.     

Fatty acid modified polyurethane dispersion for surface coatings: Effect of fatty acid content and ionic content

The higher molecular weight fatty acid modified polyurethane–urea dispersions (PUDs) were prepared with effective utilization of fatty acid and ionic emulsifier. The PUDs were prepared using oligomer of linoleic fatty acid, dimethylol propionic acid (DMPA), linear polyester diol, isophorone diisocyanate (IPDI), triethylamine (TEA) and ethylenediamine (EDA) by prepolymer mixing method. Resultant PUDs had so-called controlled branched polymer structures. To incorporate fatty acid residues in the backbone of the polyurethane two types of oligomers were used which were synthesized by esterifying linoleic acid and phthalic anhydride (PA) with different monomers having different hydroxyl functionality i.e. trimethylol propane (TMP), pentaerythritol and neopentyl glycol (NPG). The oligomers were mixed with linear polyester diol in different proportions and used as polyol part in prepolymer for PUDs. Various compositional variations such as type of oligomer, content of oligomer and ionic emulsifier were studied for stability and compatibility with water. The PUDs were also examined by FTIR, AFM, GPC, particle size analyzer, viscometer, TGA, DMA and tensile tester to analyze structures and properties. Chemical, water and corrosion resistances of the dried films were also evaluated to study the effect of oligomer content in modified PUDs. These properties are found to be significantly affected by the content and type of oligomer as well as ionic content in the polymer.     

Casting/mould interfacial heat transfer during solidification in graphite,steel and graphite lined steel moulds

Heat flow between the casting and the mould during solidification of three commercially pure metals, in graphite, steel and graphite lined steel moulds, was assessed using an inverse modelling technique. The analysis yielded the interfacial heat flux (q), heat transfer coefficient (h) and the surface temperatures of the casting and the mould during solidification of the casting. The peak heat flux was incorporated as a dimensionless number and modeled as a function of the thermal diffusivities of the casting and the mould materials. Heat flux transients were normalised with respect to the peak heat flux and modeled as a function of time. The heat flux model proposed was used to estimate the heat flux transients during solidification in graphite lined copper composite moulds.     

Deposition of hydroxyapatite coatings by axial plasma spraying: Influence of feedstock characteristics on coating microstructure,phase content and mechanical properties

Axial plasma spray is one of the thermal spray techniques to deposit multifunctional advanced coatings. The present work explores the use of this process to deposit thin, continuous, and adherent Ca₅ (PO₄)₃OH (hydroxyapatite, HAp) coatings and characterize its microstructure, phases, hardness and adhesion strength. Three different suspension-deposited HAp coatings were investigated and compared with powder-deposited HAp coating on a Ti6Al4V substrate. The effect of mean solute particle size and solid-loading in the suspension has been explored on the evolution of microstructure, phase content and mechanical properties of axial suspension plasma sprayed (ASPS) coatings. Phase-characterization has shown retention of hydroxyapatite phase and coating crystallinity in the deposited coatings, whereas the adhesion strength of the HAp coating decreased from ～40 MPa to ～13 MPa when bioglass was added to the feedstock material. The lower solid load content and lower mean solute particle size in the suspension were found to be beneficial in achieving porous, rougher, and well-adhering coatings. This work concludes that ASPS can potentially deposit thin HAp coatings (< 50 μm) with high adhesion strength.     

Performance Tuning and Reliability Analysis of the Electrostatically Configured Nanotube Tunnel FET with Impact of Interface Trap Charges

Silicon - This paper examines, an electrostatically configured Nano-Tube Tunnel Field-Effect Transistor (ED-NTTFET). During the fabrication process, different charges such as fixed charge, oxide...     

Consideration of Trends in Evaluating Inter-basin Water Transfer Alternatives within a Fuzzy Decision Making Framework

Evaluation of water supply schemes is an essential task for meeting the goals of inter-basin water transfer project system management. In general, water supply operation involves multi-objective and multifactor optimization and decision. In recent years, multicriterion decision making (MCDM) has emerged as an effective methodology due to its ability to combine quantitative and qualitative criteria for selection of the best alternative. This paper presents a new optimization method using fuzzy pattern recognition to appraise the water supply decision schemes in inter-basin diversion systems. The proposed method is capable to incorporate not only the will of the decision-makers but also the future development trend of water resources and water supply demand and makes the optimization results more reasonable and applicable. One case study for the Xi-River-to -Tanghe Reservoir Water Transfer Project System in China is presented to demonstrate the application of this method.     

Oil price,biofuels and food supply

The price of oil could play a significant role in influencing the expansion of biofuels, but this issue has yet to be fully investigated in the literature. Using a global computable general equilibrium (CGE) model, this study analyzes the impact of oil price on biofuel expansion, and subsequently, on food supply. The study shows that a 65% increase in oil price in 2020 from the 2009 level would increase the global biofuel penetration to 5.4% in 2020 from 2.4% in 2009. If oil prices rise 150% from their 2009 levels by 2020, the resulting penetration of biofuels would be 9%, which is higher than that would be caused by current mandates and targets introduced in more than forty countries around the world. The study also shows that aggregate agricultural output drops due to an oil price increase, but the drop is small in major biofuel producing countries as the expansion of biofuels would partially offset the negative impacts of the oil price increase on agricultural outputs. An increase in oil price would reduce global food supply through direct impacts as well as through the diversion of food commodities and cropland towards the production of biofuels.     

Effects of nano size mischmetal and its oxide on improving the hydrogen sorption behaviour of MgH2

This paper reports the catalytic effects of mischmetal (Mm) and mischmetal oxide (Mm-oxide) on improving the dehydrogenation and rehydrogenation behaviour of magnesium hydride (MgH₂). It has been found that 5 wt.% is the optimum catalyst (Mm/Mm-oxide) concentration for MgH₂. The Mm and Mm-oxide catalyzed MgH₂ exhibits hydrogen desorption at significantly lower temperature and also fast rehydrogenation kinetics compared to ball-milled MgH₂ under identical conditions of temperature and pressure. The onset desorption temperature for MgH₂ catalyzed with Mm and Mm-oxide are 323 °C and 305 °C, respectively. Whereas the onset desorption temperature for the ball-milled MgH₂ is 381 °C. Thus, there is a lowering of onset desorption temperature by 58 °C for Mm and by 76 °C for Mm-oxide. The dehydrogenation activation energy of Mm-oxide catalyzed MgH₂ is 66 kJ/mol. It is 35 kJ/mol lower than ball-milled MgH₂. Additionally, the Mm-oxide catalyzed dehydrogenated Mg exhibits faster rehydrogenation kinetics. It has been noticed that in the first 10 min, the Mm-oxide catalyzed Mg (dehydrogenated MgH₂) has absorbed up to 4.75 wt.% H₂ at 315 °C under 15 atmosphere hydrogen pressure. The activation energy determined for the rehydrogenation of Mm-oxide catalyzed Mg is ∼62 kJ/mol, whereas that for the ball-milled Mg alone is ∼91 kJ/mol. Thus, there is a decrease in absorption activation energy by ∼29 kJ/mol for the Mm-oxide catalyzed Mg. In addition, Mm-oxide is the native mixture of CeO₂ and La₂O₃ which makes the duo a better catalyst than CeO₂, which is known to be an effective catalyst for MgH₂. This takes place due to the synergistic effect of CeO₂ and La₂O₃. It can thus be said that Mm-oxide is an effective catalyst for improving the hydrogen sorption behaviour of MgH₂.     

Multiphase and multicomponent transport with phase change during meat cooking

A multiphase model based on unsaturated flow in a hygroscopic porous medium, which accounts for the important physical phenomena that take place during thermal treatment of meat, is developed. Frozen meat is considered as a porous solid comprising of water, fat and protein with gas trapped in its pores. As it is heated, water and fat melt, and, are gradually released from the solid protein matrix to the pore space. With further rise in temperature, liquid water evaporates. Since four fluid components (liquid water phase, liquid fat phase, water vapor and air) are present in the pore space, a mass balance equation is written for each component. Local thermal equilibrium assumption leads to one energy balance equation for the whole system. The model is validated for double-sided contact heating of hamburger patties by comparing temperature and moisture profiles with experimental studies. Dominant modes of transport are identified.