Dynamic analysis and split range control for maximization of operating range of continuous microbial fuel cell

Human development is inherently connected with availability of water and energy. Energy production requires water, whereas water treatment needs energy. On the other hand, microbial fuel cell has capability to produce energy and water simultaneously from waste water or organic matter. In this paper, first principle-based model of variable volume microbial fuel cell is simulated. Hydraulic retention time is selected as the manipulated variable using the study of steady state and dynamic responses. Classical PI and model predictive control strategies are developed for controlling the produced power from the cell, and its performance is tested for servo problem. Settling time for positive and negative set points is found to be 126 and 889 h in case of classical PI and 120 and 750 h in case of linear MPC, respectively along with large increase (three times order of magnitude) in working volume for negative set point. These control challenges are overcome by using split range controller with variable and constant volume microbial fuel cells. The settling time for negative set point is found to be 49 and 21 h for classical PI and linear MPC schemes, respectively, which is significantly lower than using only variable volume microbial fuel cell. Also, there is no increase in the working volume of the constant volume microbial fuel cell. Hence, operating range of the microbial fuel cell is enhanced using split range controller.     

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.     

Study of pyro-carbon coated alumina kernel using mixed contrast transfer based X-ray phase retrieval technique

We have used the contrast transfer function based X-ray phase retrieval technique for phase retrieval studies on a two-component system. Pyro-carbon coated alumina matrix was chosen as a two-component system for these studies. Simulations as well as experimental results are presented. This paper shows that X-ray phase contrast along with phase retrieval can become an alternative tool for non-destructive characterization of these materials. We have also attempted to retrieve the spatial distribution of the projected thickness map of the two different elements.     

Voltammetric determination of citric acid and quinine hydrochloride using polypyrrole–pentacyanonitrosylferrate/platinum electrode

Cyclic voltammetry was used to investigate the electrochemical behavior of citric acid (CA) and quinine hydrochloride (QH) at a polypyrrole-pentacyanoferrate/Platinum (PPY–PCNFe/Pt) electrode in aqueous medium. The analytical plots obtained were found to be linear in the concentration range between 1.0 and 9.0 mM for both the analyte solutions. The detection limits (3δ) were found to be 1.17 × 10^?4 M and 1.08 × 10^?5 M for CA and QH analyte solutions, respectively. It was further observed that the diffusion of ionic species into and out of the polymeric film made the PPY–PCNFe/Pt electrode highly electroactive thereby enabling it to efficiently detect the analyte solutions having concentration as low as 1 mM.     

Waste-to-energy: A way from renewable energy sources to sustainable development

Nowadays, energy is key consideration in discussions of sustainable development. So, sustainable development requires a sustainable supply of clean and affordable renewable energy sources that do not cause negative societal impacts. Energy sources such as solar radiation, the winds, waves and tides are generally considered renewable and, therefore, sustainable over the relatively long term. Wastes and biomass fuels are usually viewed as sustainable energy sources. Wastes are convertible to useful energy forms like hydrogen (biohydrogen), biogas, bioalcohol, etc., through waste-to-energy technologies.In this article, possible future energy utilization patterns and related environmental impacts, potential solutions to current environmental problems and renewable energy technologies and their relation to sustainable development are discussed with great emphasis on waste-to-energy routes (WTERs).     

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.     

Fusing Loop Detector and Probe Vehicle Data to Estimate Travel Time Statistics on Signalized Urban Networks

Abstract: This article presents a methodology that integrates cumulative plots with probe vehicle data for estimation of travel time statistics (average, quartile) on urban networks. The integration reduces relative deviation among the cumulative plots so that the classical analytical procedure of defining the area between the plots as the total travel time can be applied. For quartile estimation, a slicing technique is proposed. The methodology is validated with real data from Lucerne, Switzerland and it is concluded that the travel time estimates from the proposed methodology are statistically equivalent to the observed values.     

In Situ Confocal Raman Mapping Study of a Single Ti-Assisted ZnO Nanowire

In this work, we succeeded in preparing in-plane zinc oxide nanowires using a Ti-grid assisted by the chemical vapor deposition method. Optical spatial mapping of the Confocal Raman spectra was used to investigate the phonon and geometric properties of a single ZnO nanowire. The local optical results reveal a red shift in the non-polar E₂ high frequency mode and width broadening along the growth direction, reflecting quantum-confinement in the radial direction.     

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.     

Effect of boiling and roasting on the polyacetylene and polyphenol content of fennel (Foeniculum vulgare) bulb

Fennel (Foeniculum vulgare cv dulce.) is a hardy, perennial, umbelliferous (Apiaceae) plant as a source of the secondary metabolites group's polyacetylenes and polyphenols.The present study investigated the effect of boiling (100 ° C for 30 min) and roasting (160 °C for 15 min) on the levels of these phytochemicals. Boiling resulted in a significant decrease in the levels of polyacetylenes (falcarinol, falcarindiol, falcarindiol- 3- acetate) and polyphenols (caffeic acid, gallic acid, apigenin-7-o-glucoside, ferulic acid, syringic acid, isovitexin, phloridzin). The loss of polyphenols from the boiled bulbs may be in part due to leaching of these components in the water. Roasting resulted in a significant decrease in falcarindiol, falcarindiol-3-acetate, and falcarinol by 81%, 78%, and 66% when compared to raw unprocessed fennel bulbs. In general, levels of all polyphenols decreased in roasted samples. The exceptions were ferulic acid which showed an increase and gallic acid which did not show any decrease. In line with results for polyphenol levels, antioxidant activity decreased following thermal processing, and the presence of hydroxymethylfurfural was confirmed in roasted samples of fennel.