Multiple Order Dual-Band Active Ring Filters with Composite Right/Left Handed Cells

In this paper, a novel dual-band active filter topology is presented. The non-linear phase response of a composite right/left-handed cell is used to achieve the desired dual-band performance. Additionally, the proposed structure based on coupled ring resonators yields a very compact solution in which high-order implementations can be easily obtained by cascading multiple rings. The theoretical principles of this type of filters are analyzed in detail. Finally, three prototypes based on first-, second- and third-order structures validate the feasibility of this type of filters. Good agreement between simulations and measurements has been achieved

Noise Figure Measurement of Differential Amplifiers Using non-Ideal Baluns

This paper analyzes the noise and gain measurement of microwave differential amplifiers using two passive baluns. A general model of the baluns is considered, including potential losses and phase/amplitude unbalances. This analysis allows de-embedding the actual gain and noise performance of the isolated amplifier by using single-ended measurements of the cascaded system and baluns. Finally, measured results from two amplifier prototypes are used to validate the theoretical principles

Characterization of an infectious pancreatic necrosis (IPN) virus carrier cell culture with resistance to superinfection with heterologous viruses

A state of persistence of a non susceptible fish cell line with infectious pancreatic necrosis virus (IPNV) was established in vitro by experimental infection. The persistently infected culture showed sustained production of infectious virus and could be continuously passaged for months. A distinct feature of this culture is that only a very small fraction of the cells harbours virus replication, in contrast to other reported IPNV-persistently infected cells from salmonid fish, where nearly all the cells express viral antigens. In spite of the small number of detectable IPNV-infected cells, the carrier culture shows resistance to superinfection with homologous as well as heterologous viruses. Temperature shift-up experiments indicate that viral interference is due to continuous replication of IPNV in the culture. Quantitation of Mx gene expression suggested that the interference phenomenon could be mediated by the activation of the interferon (IFN) system. However, conditioned medium from the IPNV-infected cell cultures only marginally protected other cells against VHSV infection, indicating that other type I IFN-independent mechanism may be underlying the resistance of the persistently infected culture to infection with heterologous viruses. Our study defines a novel in vitro model of IPNV persistence and contributes to the understanding of the widespread distribution of aquabirnaviruses in marine and fresh water environments by establishing a carrier state in non susceptible fish species

Método de desembebido para la caracterización de amplificadores diferenciales usando baluns pasivos

This paper analyses the noise and gain measurement of microwave differential amplifiers using two passive baluns. A model of the baluns that includes potential losses and unbalances has been considered. This analysis allows de-embedding actual performance of the differential device from the single-ended measurements of the two-port cascaded system and the baluns. The method has been validated with measured results from a fully-differential amplifier prototype

A De-Embedding Method to Characterize Differential

This paper analyses the noise and gain measurement of microwave differential amplifiers using two passive baluns. A model of the baluns that includes potential losses and unbalances has been considered. This analysis allows to de-embed the actual performance of the differential device from the single-ended measurements of the two-port cascaded system and the baluns. The method has been validated with measured results from a fully-differential amplifier prototype

Cell-Culture Measurements Using Voltage Oscillations

A comprehensive system for real-time monitoring of a set of cell-cultures using a Voltage Oscillation (VO) methodology is proposed. The main idea is to connect the bio-electrical elements (electrodes & cell-culture) in such a way that sequentially a suitable electrical oscillator, which only uses a DC power source, is built. Using the employed electrical models given in [1, 2], the attained oscillation parameters (frequency and amplitude) can be directly related to the biological test. A digital circuitry is developed to pick-up the experimental measurements, which are gathered and shown in real-time in a web application.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-

Towards Bio-impedance Based Labs: A Review

In this article, some of the main contributions to BI (Bio-Impedance) parameter-based systems for medical, biological and industrial fields, oriented to develop micro laboratory systems are summarized. These small systems are enabled by the development of new measurement techniques and systems (labs), based on the impedance as biomarker. The electrical properties of the life mater allow the straightforward, low cost and usually non-invasive measurement methods to define its status or value, with the possibility to know its time evolution. This work proposes a review of bio-impedance based methods being employed to develop new LoC (Lab-on-a-Chips) systems, and some open problems identified as main research challenges, such as, the accuracy limits of measurements techniques, the role of the microelectrode-biological impedance modeling in measurements and system portability specifications demanded for many applications.Spanish founded Project: TEC 2013-46242-C3-1-P: Integrated Microsystem for Cell Culture AssaysFEDE

Interactive data visualization of chatter conditions in a cold rolling mill

Artículo publicado en abierto mediante APC Elsevier Open AccessRolling of flat steel products is an industrial process in the field of metalworking where two or more pairs of rolls reduce the thickness of a steel strip to produce a uniform thickness material. Despite it has been studied for many years, there are still unpredictable problems that can affect the final quality of the product. One of them is the so-called chatter, that is a powerful self-excited vibration that appears suddenly and limits the productivity of the process. In this paper, a visual analytics approach is considered for exploratory analysis in order to discover and understand the factors and conditions under which chatter appears. An interactive web-based interface is presented here which allows the user to explore a map of dynamical conditions and visualize relevant details of each chatter onset. A validation case is performed using real data where normal/fault conditions have been identified automatically. By means of interactive exploration, the tool allows to refine an automatic chatter detection method. Moreover, it is shown to reveal correlations between variables, providing in some expected cases data-based confirmation, but also revealing less obvious relationships. Finally, it provides context, allowing to carry out comparative analysis, both qualitative and quantitative, for different subsets of coils (e.g. different years) as well as for different working condition

Electrosynthesis of 2,3-butanediol and methyl ethyl ketone from acetoin in flow cells

Acetoin could shortly become a platform molecule due to current progress in fermentation technology, the megatrend for shifting from an oil-based economy to one based on biomass, the quest for green manufacturing processes and its two highly reactive carbonyl and hydroxyl moieties. In this paper, the successful electro-conversion of acetoin into two valuable chemicals, 2,3-butandiol (2,3-BD) and methyl ethyl ketone (MEK), at constant electrical current in aqueous phase at room temperature using both divided and undivided 20 cm2 filter-press flow cells under experimental conditions suitable for industrial production is reported. Cathode material is the key parameter to drive the electroreduction towards one or another chemical. 2,3-BD is the major chemical produced by electrohydrogenation when low hydrogen overvoltage cathodes, such as Pt and Ni, of high surface area obtained by PVD coating on a carbon gas diffusion layer are used, while MEK is the principal product produced by electrohydrogenolysis when high hydrogen overvoltage cathodes, such as graphite, Pb and Cd foils, are employed. 2,3-BD and MEK can be obtained, respectively, in 92.8% and 85.7% selectivities, 71.7% and 80.4% current efficiencies, with 1.21 and 1.08 kg.h-1.m-2 productivities and power consumptions of 2.94 and 4.1 kWh.kg-1 using undivided cells and aqueous K2HPO4 electrolysis media at pHs of 3.6 and 5.5. The reported electroconversion of acetoin is highly flexible because 2,3-BD and MEK can be produced by changing just the cathode but using the same cell, with the same electrolyte at the same current density