Spontaneous Formation of Complex Periodic Superstructures under High Interferential Illumination of Small‐Molecule‐Based Photochromic Materials

A series of push‐pull azo compounds containing bulky substituents are synthesized, yielding fully amorphous materials with glass‐transition temperatures above 200 °C. Thin films are subjected to holographic illumination and show superior bulk photomigration in terms of speed and efficiency compared to materials exhibiting similar electronic and photochromic properties in the solid state. The reported results give evidence that a microscopic consideration of the free volume rather than macroscopic parameters like the glass‐transition temperature should to be adopted to interpret the matrix stiffness and its deformation ability. Irradiation performed at higher laser intensity produces periodic superstructures whose height is five to six times as high as the initial film thickness. The surface tension and instability effects are put forward to interpret the growth of such superstructures.     

Tap Water Costs and Service Sustainability, a Close Relationship

Water is currently an essential and strategic resource for society and its importance will rise in the future due to the increasing number of threats. However, water management is not currently up to par taking into consideration this well acknowledged importance. Generally speaking, water use is not efficient and loss figures are often too high. The reasons behind this situation are complex and diverse, however, in principle, they can be divided into four categories: cultural, political, social and economic. Since the latter are of most importance, this paper focuses on water costs from source to tap. The economic analysis presented quantifies the costs of a sustainable urban water service in a structured way. The second part of the paper present a case study in which the economic losses linked to leakage are assessed as a function of how expenses are recovered. The cost of apparent losses could also be assessed in a similar way and will always be higher, since apparent losses (unlike real ones) are present throughout the whole water cycle, thus increasing the unit costs.     

Generation management using batteries in wind farms: Economical and technical analysis for Spain

This paper presents an hourly management method for energy generated in grid-connected wind farms using battery storage (Wind–Batteries systems). The method proposed is analysed technically and economically.     

THE LAMINAR FLOW TUBULAR REACTOR WITH HOMOGENEOUS AND HETEROGENEOUS REACTIONS II. Application to Reactor Modeling Involving Free Radical Reactions

The simulation of the complex polychlorination of methane in a non-isothermal photoreactor with laminar flow regime shows the usefulness of the integral equations deduced in Part I of this contribution. Improved iterative schemes for numerical solution have been implemented by using the particular equations proposed for species having slow, very fast and instantaneous reaction regimes.

From such integral equations, in a mathematically consistent form, deviations in the fields of predicted concentrations with and without the application of the local steady-state approximation for homogeneous reactions involving atomic and free radical species have been obtained. Similarly the fields of predicted concentrations applying the usual assumption of negligible wall reactions for the same highly reactive intermediate species has been compared with the reaction mechanisms that includes the wall reactions. A comprehensive analysis of the validity of these simplifying assumptions is presented.     

Embryonic States of Fluorapatite–Gelatine Nanocomposites and Their Intrinsic Electric‐Field‐Driven Morphogenesis: The Missing Link on the Way from Atomistic Simulations to Pattern Formation on the Mesoscale

The shape development of fluorapatite (FAP)–gelatine nanocomposites is revealed by means of HRTEM investigations starting from molecular dimensions up to the formation of mesoscaled (elongated) hexagonal prisms. The composite nature of the aggregates is proved by IR spectroscopy and by chemical analyses on all states of shape development. The initial states are characterized by triple‐helical fiber protein bundles, which are mineralized step‐by‐step forming and fixing nanoplatelets of FAP in a mosaic arrangement. After being fully mineralized the bundles form elongated composite nanoboards. In the next step of the growth process the boards aggregate to bundles of boards which are in a more or less parallel alignment with respect to each other. By adding up more and more composite nanoboards a critical size is reached and an electric field is developed, which takes over control and directs the further development of the aggregates. This kind of electric‐field‐directed growth of the elongated polar nanoboards additionally leads to the formation and inclusion of protein nanofibrils into the growing composite aggregate. By this method, cone‐like nanofibril structures develop along the long axis of the aggregates accompanied by more perfect parallel alignment of the composite boards within the aggregates. Further shape development is characterized by adding up composite nanoboards, in particular to increase the third dimension in volume. This thickening process preferably takes place in the middle part of the elongated aggregates and finally proceeds to their basal ends until a perfect hexagonal prismatic seed is formed, which then is ready for further shape development on the micrometer scale.     

Synthesis of Proton Exchange Membranes with Pendent Phosphonic Acid Groups by Irradiation Grafting of VBC

Proton exchange membranes with pendent phosphonic acid groups were synthesized by pre‐irradiation grafting from vinylbenzyl chloride onto FEP and ETFE films with subsequent Arbuzov phosphonation. Free phosphonic acid groups, which are necessary for proton conductivity, were obtained by acid ester hydrolysis. The phosphonated membranes were characterized by phosphonation degree, FTIR‐spectroscopy, ion exchange capacity (IEC), oxidation stability, swelling properties, and thermal properties (TGA).     

Estimation of chromium bioavailability from the diet by an in vitro method.

An in vitro method was used to study the dialysable fraction of chromium (Cr) from the diet which simulates human gastric and intestinal digestion. The percentage of dialysed Cr was used to assess the bioavailability. The duplicate diet approach was used to obtain ten different sets of samples each representative of the normal diet consumed in southern Spain. In each case triplicate analysis of Cr was carried out by electrothermal atomization-atomic absorption spectrometry in acid-mineralized samples. The Cr dietary intake ranged from 16 to 117 microg/day, and the dialysable Cr fraction ranged from 0.4% to 1.6%. The Cr absorption was higher for low levels of daily dietary intake of Cr (< 40 microg) than for levels of 40-80 microg; for high levels (> 80 microg) there was an increase in the dialysable fraction. The energy and nutrient intake of these diets was also evaluated.     

A Novel Direct Method for Determination of Riboflavin in Alcoholic Fermented Beverages

A novel cheap and user friendly method for the determination of riboflavin in wine and beer samples has been developed based on the fluorescence quenching effect given by riboflavin binding to the chicken egg white, riboflavin-binding protein. The method is based on the use of a single diode fluorimeter with emission within riboflavin absorption profile. Linearity was observed over riboflavin concentration from 0 to 500 ng/mL with a limit of detection of 15 ng/mL. Data on real wine and beer samples were obtained and compared with classical high-performance liquid chromatography (HPLC)-based method. The fluorimetric method thus appears much faster and cheaper than the chromatographic one and easily amenable to routine analysis in beverage industry.