New acrylic monolithic carbon molecular sieves for O2/N2 and CO2/CH4 separations

The modification of activated carbon fibres prepared from a commercial textile acrylic fibre into materials with monolithic shape using phenolic resin as binder was studied. The molecular sieving properties for the gas separations CO₂/CH₄ and O₂/N₂ were evaluated from the gas uptake volume and selectivity at 100 s contact time taken from the kinetic adsorption curves of the individual gases. The pseudo-first order rate constant was also determined by the application of the LDF model. The samples produced show high CO₂ and O₂ rates of adsorption, in the range 3-35 × 10⁻³ s⁻¹, and in most cases null or very low adsorption of CH₄ and N₂ which make them very promising samples to use in PSA systems, or similar. Although the selectivity was very high, the adsorption capacity was low in certain cases. However, the gas uptake in two samples reached 23 cm³ g⁻¹ for CO₂ and 5 cm³ g⁻¹ for O₂, which can be considered very good. The materials were heat-treated using a microwave furnace, which is a novel and more economic method, when compared with conventional furnaces, to improve the molecular sieves properties.     

Selective Modification of Pt Active Sites on Pt–Au/C Catalysts Prepared by Surface Redox Reactions

This study focused on the selective deposition of Au⁰ onto (111), (100) faces and (111)/(100) edges of cuboctahedral Pt particles present on the Pt/C(graphite) model system. The Pt–Au/C catalysts were prepared by novel surface redox methods involving the direct reduction (DR) of AuCl ₄ ^– species onto the Pt particles or reducing these species on the Pt–H interface, i.e., the refilling (RE) method. The presence of Au on the Pt particles was verified by means of high-resolution energy dispersive spectroscopy (EDS), and, after treatment at 300°C in H₂, the formation of crystalline Au⁰ aggregates was verified by X-ray wide-angle diffraction; further treatments at 500°C in H₂ led to a true Pt–Au solid solution. The Monte Carlo simulation methods indicated the selective deposition of Au⁰ onto the (111)/(100) edges of the Pt cuboctahedral particles when the relative Au concentration varied from 10 to 50 wt% Au. The catalytic conversion of n-heptane on the Pt–Au/C (DR and RE solids) catalysts presented an oscillatory behavior with respect to Pt/C, indicating modification of the active Pt ensembles, driven by the energy released during the exothermic n-C₇ dehydrogenation and cracking reactions, which should enhance the Au⁰ mobility at the Pt particle surface level.     

Effect of emulsifier type on the copolymerization of styrene and acrylic acid

In this work we report the emulsion copolymerization of styrene and acrylic acid using a cationic (cetyltrimethylammonium bromide or CTAB) or an anionic (sodium dodecylsulfate or SDS) emulsifier. Latexes were stable and monodisperse with spherical particles of ～100 nm for the CTAB latex and of ～70 nm for the SDS latex. However, a random copolymer was produced with CTAB whereas a “blocky” copolymer was obtained with SDS. Here we propose a mechanism to explain these structural differences in terms of the relative reactivities of styrene and acrylic acid and of their initial location and distribution in the SDS and CTAB emulsions.     

Kinetics of the reaction between ozone and phenolic acids present in agro-industrial wastewaters

The kinetics of the ozonation of three phenolic acids is investigated from ozone absorption experiments in a semi-continuous reactor. After the evaluation of stoichiometric ratios for the individual reactions between ozone and each phenolic acid, the oxidation of p-hydroxybenzoic acid by ozone is performed in a first stage. The influence of the operating variables on the degradation process is established, and the application of a mass transfer with chemical reaction model based on the film theory leads to the determination of the reaction orders and kinetic rate constants. The experimental absorption rates obtained agree well with those calculated theoretically. In the second stage, a mixture of ferulic acid (4-hydroxy-3-methoxycinnamic acid), beta-resorcylic acid (2,4-dihydroxybenzoic acid) and p-hydroxybenzoic acid is ozonated under different experimental conditions. The kinetic study is performed by means of a competitive method that takes p-hydroxybenzoic acid as reference compound. The application of this model allows to determine the kinetic rate constants for each compound, which are correlated as a function of pH and temperature. The results obtained support that the kinetic regime of absorption is fast and pseudo-first order with respect to ozone, a condition required by the competitive method used.     

Characterization using thermomechanical and differential thermal analysis of the sinterization of Portland clinker doped with CaF2

In this work, the sintering process of Portland cement was studied by combining thermomechanical analysis (TMA) and differential thermal analysis (DTA), together with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal analysis results employing both techniques indicted that phase transformations appeared at lower temperatures when CaF₂ was incorporated in the raw materials. Besides, it was observed at high temperature that in some phase transformations TMA conducts to better resolution compared with the DTA measurements. Furthermore, mechanical properties and X-ray diffraction patterns corroborate the TMA and DTA results, corroborating that the final amount of alite (Ca₃SiO₅) is higher when a certain amount of CaF₂ was present during the clinkerization process.     

Remote Laboratory Architecture for the Validation of Industrial Control Applications

The seven engineering degrees of the Higher Technical School of Design Engineering (ETSID), Technical University of Valencia, include in their formation programs, subjects, and laboratory projects to instruct students in the aspects of the design, development, and validation of applications for process control, automation, industrial informatics, and embedded systems. Moreover, the authors participate in European projects of education such as the International Network of Embedded System (INES) and the European Project Semester (EPS), where exchange students remotely perform the first phase of their projects at ETSID from their home universities. To significantly reduce the cost of installing a huge number of real prototypes in labs and to fulfill the distance requirements of the exchange students, a remote laboratory architecture, i.e., simPROCes, has been designed. simPROCes not only permits the teleoperation of simulators/real prototypes but also allows that complete control applications be remotely tested and validated. simPROCes is precisely specified to be independent of the model of computer, data acquisition card, programming language, and operating system, and is transparent to the programmer and easy to use. This system is useful both for the education and development of control application purposes. A water tank process shows the installation procedure of simPROCes to test and validate control applications. The experience of applying simPROCes in the electronic engineering degree and within the framework of INES and EPS has been successfully rated by student surveys.     

Case-Based Reasoning and System Identification for Control Engineering Learning

This paper presents a novel Web service encouraging active learning by students. The students are able to use physical systems in a remote way, obtaining explanatory feedback on whether their actions are correct or incorrect. This service is based on system identification (SI) techniques to gain a knowledge of the physical system involved and case-based reasoning (CBR) for exploiting this knowledge. Uniting CBR and SI, an emulation of the real physical system is achieved that permits resolution of the problems of real-time access and simultaneous multiuser access that currently exist in remote-learning laboratories.     

Water scarcity: Can virtual water operators help?

The changing climate is likely to have an effect on water and sewerage sectors. To deal with this challenge regulators need consider ways to better signal the value of water, that is, such that water is more expensive where it is scarce. This paper shows that virtual water operators (VWO) could result in entrants internalising this value and provide regulators with an estimate of it. With water scarcity, entrants will face higher cost of entry as they will need to acquire expensive, if available, abstraction licences. Given these higher prices they will also be willing to pay higher prices to become a VWO in those areas with scarcity. This means that VWOs can help to reveal the real value of water. Further, by introducing these considerations into part of the incumbent’s capacity, VWO also help to introduce this cost into the supply of the incumbent.     

Direct detection of lower hybrid wave using a reflectometer on Alcator C-Mod

The possibility of directly detecting a density perturbation produced by lower hybrid (LH) waves using a reflectometer is presented. We investigate the microwave scattering of reflectometer probe beams by a model density fluctuation produced by short wavelength LH waves in an Alcator C-Mod experimental condition. In the O-mode case, the maximum response of phase measurement is found to occur when the density perturbation is approximately centimeters in front of the antenna, where Bragg scattering condition is satisfied. In the X-mode case, the phase measurement is predicted to be more sensitive to the density fluctuation close to the cut-off layer. A feasibility test was carried out using a 50 GHz O-mode reflectometer on the Alcator C-Mod tokamak, and positive results including the detection of 4.6 GHz pump wave and parametric decay instabilities were obtained.