Simultaneous Separation and Detection of Cations and Anions Ion a Microfluidic Device with Suppressed Electroosmotic Flow and a Single Injection Point

A rapid and simultaneous separation of cationic and anionic peptides and proteins in a glass microfluidic device that has been covalently modified with a neutral poly(ethylene glycol) (PEG) coating to minimize protein adsorption is presented. The features of the device allow samples that contain both anions and cations to be introduced from a central flow stream and separated in different channels with different outlets—all in the presence of low electroosmotic flow (EOF) imparted by the PEG coating. The analytes are electrophoretically extracted from a central hydrodynamic stream and electrophoretically separated in two different channels, in which pressure driven flow has been suppressed through the use of hydrodynamic restrictors. Having different outlets for the electrophoretic separation channels that are spatially separated from the injection enables coupling with further downstream functionalities or off-chip detection, such as mass spectrometry. A plug of charged analyte is hydrodynamically pumped to the sampling intersection and anions from the plug migrate electrophoretically toward the anode in one channel while cations migrate toward the cathode in the other channel due to suppressed EOF from the PEG coating. The separations presented here required less than a minute to complete and produced average separation efficiencies of up to about 3,500 plates from a separation length of 2 cm. The extraction efficiency of both cations and anions from the hydrodynamic stream is determined experimentally and compared with a previously reported model that was used to determine anion extraction efficiency. The extraction efficiency is determined to be 87% and 98% for the two sample mixtures analyzed, and the values predicted by the model are within 3.5% of the experimental data. It is anticipated that this basic approach for simultaneous separation of anions and cations with reduced EOF will be integrated into larger microfluidic systems because the design provides separate outlets that can feed downstream processes or linked to off-chip detection

Ensayos de dinteles de fábrica de ladrillo atirantada sobre los nuevos Apoyos Pi, distanciados 6m entre sí

Comunicación presentada en las II Jornadas de Investigación en Construcción: "60 años de Informes de la Construcción", celebradas los pasados 22, 23 y 24 de mayo de 2008 en el Instituto "Eduardo Torroja" de Ciencias de la Construcción (IETCC-CSIC) de Madrid.Comparando la Arquitectura de Ladrillos del s.XIX con el empleo del ladrillo en la Arquitectura del s.XX, se puede observar que abunda mayor patología en las fábricas de ladrillo cara vista recientes que en las más antiguas. El primer paso para prevenir la abundante fisuración de la albañilería apreciada en España a finales del siglo pasado, se dio en 1992, con la realización del "Manual Murfor: La fábrica armada", estableciéndose en él los criterios posteriormente contemplados en el "Eurocódigo 6: Estructuras de Fábrica", de recomendar armar con el 0,03% de la sección del muro, y a distancias verticales no mayores de 600mm. Las primeras aplicaciones arquitectónicas de la fábrica armada en España, fueron realizadas por este Arquitecto en sus obras de la Plaza de la Remonta y de El Espinillo, divulgándose por su potencial arquitectónico, tanto en Europa como en América.En este artículo se retoman las posibilidades del incremento de prestaciones de la fábrica armada Murfor con "arcos atirantados ciegos de gran luz", establecidas por primera vez en el Manual español, lo que permite salvar 6m de luz con solamente 2 armaduras Murfor de 5mm de diámetro en la parte inferior de los dinteles.Los autores agradecen la inestimable colaboración de los Institutos de Investigación IBAC de Aachen (Alemania) y el I.E. Torroja de Madrid (España), por haber hecho posible esta interesante colaboración investigadora europea de valor internacional.Peer reviewe

6m Span Lintels Tests on a New Wall Pi-brackets Type

Reinforced masonry has been subject to research and investigation in Spain for over 20 years now. This paper presents a new contribution within the AllWall System, referred to as the Halfen-Allwall support (Pi-Bracket). This support being regularly spaced every 6m to form a "braced arch" effect and provide reinforced masonry. This line of investigation has been made possible through the industrial development of a new patented invention under the trade name Halfen-AllWall Pi-Brackets in combination with Murfor brickwork reinforcement. This combination provides a new way of supporting external walls at fixed points coinciding with the verticals of the structural supports. The system prevents the loading of slabs which, in addition to providing great economy in construction, inhibits cracking due to structural deformation at the support base of the wall and also allows the continuation of insulation and ventilation throughout the cavity. Three tests of the Pi-Brackets have been made in Germany and other three 6m span walls on the Pi-Brackets, have been tested in Instituto Eduardo Torroja (Madrid). The results of this research opens a new solutions for the enclosure masonry walls, that is wide use in the Spanish building for its economy and easy construction

Density, conductivity, viscosity, and excess properties of (pyrrolidinium nitrate-based Protic Ionic Liquid + propylene carbonate) binary mixture

International audienceDensity, ρ, viscosity, η, and conductivity, σ, measurements of binary mixtures containing the pyrrolidinium nitrate Protic Ionic Liquid (PIL) and propylene carbonate (PC), are determined at the atmospheric pressure as a function of the temperature from (283.15 to 353.15) K and within the whole composition range. The temperature dependence of both the viscosity and conductivity of each mixture exhibits a non-Arrhenius behaviour, but is correctly fitted by using the Vogel–Tamman–Fulcher (VTF) equation. In each case, the best-fit parameters, such as the pseudo activation energy, and ideal glass transition temperature, T0 are then extracted. The excess molar volumes VE, and viscosity deviations from the ideality, Δη, of each investigated mixture were then deduced from the experimental results, as well as, their apparent molar volumes, Vϕ, thermal expansion coefficients αp, and excess Gibbs free energies (ΔG∗E) of activation of viscous flow. The VE, αpE, Δη values are negative over the whole composition range for each studied temperature therein. According to the Walden rule, the ionicity of each mixture was then evaluated as a function of the temperature from (283.15 to 353.15) K and of the composition. Results have been then discussed in terms of molecular interactions and molecular structures in this binary mixture