A Facile Measurement of Heterogeneous Electron Transfer Kinetics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O uso corporativo do território brasileiro no período técnico-científico-informacional: o circuito espacial produtivo e círculos de cooperação da empresa Natura

In the current historical period marked by globalization and neoliberal policies have seen the pursuit of expanded reproduction of capital by corporations, which make from the deepening territorial division of labor, ie, the increasing presence of its circuit productive space within steps towards the relations between capital and labor. This capital increase is made possible mainly by exploiting precarious forms of labor. In Brazil today, much of the population enjoys the possibilities of consumption, due mainly to the policy measures implemented in the last decade, this situation favors further expansion of large companies in our territory, thus the circuit analysis of spatial production of cosmetics contributes to a political debate about the uses of the national territory. Given that companies are organizations whose actions occur inseparably technical systems that make up the territory, this course conclusion work seeks to understand the circuit of production space and cooperation circles cosmetics company Natura Cosmetics S/A

lmmittance electroanalysis in diagnostics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A novel single-phase ZCS-PWM high power factor boost rectifier

This paper presents a novel single-phase high power factor PWM boost rectifier, featuring soft commutation of the active switches at zero-current (ZCS). It incorporates the most desirable properties of the conventional PWM and the soft-switching resonant techniques. The input current shaping is achieved with average current mode control, and continuous inductor current mode. This new PWM converter provides ZCS turn-on and turn-off of the active switches, and it is suitable for high power applications employing IGBTs. Principle of operation, theoretical analysis, a design example, and experimental results from a laboratory prototype rated at 1600 W with 400 Vdc output voltage are presented. The measured efficiency and power factor were 96.2% and 0.99 respectively, with an input current THD equal to 3.94%, for an input voltage THD equal to 3.8%, at rated load.

Untersuchungen zur Zell-Transistor-Kopplung mittels der Voltage-Clamp-Technik

Untersuchungen zur Zell-Transistor Kopplung mittels der Voltage-Clamp TechnikIn der vorliegenden Arbeit wird die extrazelluläre Einkopplung elektrischer Signale von Zellen in Transistoren hinsichtlich der an der Kopplung beteiligten Parameter untersucht. Dafür werden Zellen aus Primärkulturen und von Zell-Linien direkt auf den aktiven Sensorflächen der hergestellten Chips kultiviert. Für die Experimente werden n- und p-Kanal Feldeffekttransistoren (FET) sowie Extended-Gate-Elektroden (EGE) mit Gold- und Titanoberflächen entwickelt.Zur Untersuchung der Kopplungseigenschaften werden die neuronale Zell-Linie SH-SY5Y, die humane Endothel Zell-Linie EA.hy-926 sowie als Primärzellen hippocampale Neuronen und Kardiomyozyten embryonaler und neonataler Ratten eingesetzt. Die Voltage-Clamp Technik erlaubt die Untersuchung spannungsgesteuerter Ionenkanäle in der Zellmembran. Maßgebend für den Signalverlauf des extrazellulär eingekoppelten Signals ist der Ionenstrom von Na+, K+ und Ca2+ durch die Membran im Kontaktbereich zwischen Zelle und Sensor.Die Kopplung kann elektrisch mithilfe eines Ersatzschaltkreises beschrieben werden, der alle beteiligten elektrischen Größen der Membran und der Ionenströme, sowie die Parameter des Kontaktbereichs und des Sensors enthält.Die Simulation der extrazellulären Signale zeigt, dass die beobachteten Signalformen nur durch eine Erhöhung der Ionenkanaldichten und dadurch einer deutlich vergrößerten Leitfähigkeit der Ionenarten im Kontaktbereich gegenüber der freien Membran erklärt werden können.

Diseño de Arrays de Ranuras Compuestas Mediante Circuito Equivalente

Results of the methodology presented in [1] is shown in this document. By means of the equivalent circuit model [2][3] of the slot, a combination of Method of Moments (MoM) and Forward Matching Procedure (FMP) is used to design a sub-array of compound slots. According to this, the system can be seen as a matched electric circuit and/or as a Nelements radiating device. Comparison between commercial solvers and proposed method are shown in this document, revealing that the mutual coupling between elements is a tiltingangle-dependant parameter.

Aprendizaje multimedia en inglés: Análisis de circuitos

Este proyecto tiene como objetivo facilitar el aprendizaje multimedia en inglés de los conceptos básicos relacionados con el análisis de circuitos para los alumnos de grado de la nuestra escuela, en especial para los de nuevo ingreso. El aprendizaje será realizado directamente en inglés, cumpliendo así el doble objetivo: por un lado el de abordar unos conceptos nuevos para el alumno de ingeniería y, además, el poder hacerlo en inglés, lo que le servirá para llegar a mejorar su nivel de competencia en la lengua extranjera, o al menos mantenerlo. El proyecto realizado tiene varios apartados. En primer lugar, un apartado didáctico en el que se exponen los conceptos básicos sobre el análisis de circuitos que se quieren explicar, siempre orientados al aprendizaje de inglés. Para abordar estos nuevos temas de un modo didáctico y que incite al autoaprendizaje, se recurrirá a la tecnología y por medio de vídeos e imágenes y actividades didácticas multimedia se podrá afrontar la asignatura con facilidad e interés para captar los conceptos en una lengua extranjera. Se han diseñado actividades para la práctica de: la audición, con dictado y asociación de sonidos con palabras; de la comprensión lectora y adquisición de vocabulario, con ejercicios de rellenar huecos y emparejar definiciones. Las actividades se han adaptado a la plataforma Moodle para obtener la retroalimentación de los alumnos, si se desea. El apartado de aprendizaje se complementará con un glosario específico y alfabéticamente ordenado donde también dispondremos de la transcripción fonética de cada una de las palabras incluidas en el mismo. Para llegar a conseguir el objetivo didáctico se ha diseñado un sitio web capaz de albergar todo el contenido anterior. Abstract The main objective of this Project has been to facilitate a multimedia resource for learning in English the basic concepts related to circuit analysis. The final product is directly addressed to the undergraduate students at a Telecommunications School, the EUITT from Universidad Politécnica de Madrid. Learning technical notions directly in English serves the students to reach the double purpose of not only acquiring a number of new concepts but also improving their proficiency in the foreign language or keeping up with their level of English through their studies. The project has several sections. There is a didactic section which explains the basic concepts using videos and images in order to approach the subject with ease and interest. This part is supplemented with a glossary in alphabetic order provided with the phonetics of the English words and some multimedia exercises for practicing different skills mainly listening, reading, and using technical vocabulary in English. All these activities have been adapted to the platform Moodle so that the students results can be assessed, if convenient. On the other hand, the practical implementation of the Project has consisted of designing a website capable of including all of the points mentioned above.

Variable impedance LED matrix control system for lamps in PV applications

The interest in LED lighting has been growing recently due to the high efficacy, lifelime and ruggedness that this technology offers. However the key element to guarantee those parameters with these new electronic devices is to keep under control the working temperature of the semiconductor crystal. This paper propases a LED lamp design that fulfils the requ irements of a PV lighting systems, whose main quality criteria is reliability. It uses directly as a power supply a non·stabilized constant voltage source, as batteries. An electronic control architecture is used to regulate the current applied to the LEO matri)( according to their temperature and the voltage output value of the batteries with two pulse modulation signals (PWM) signals. The first one connects and disconnects the LEOs to the power supply and the second one connects and disconnects several emitters to the electric circuit changing its overall impedance. A prototype of the LEO lamp has been implemented and tested at different temperaturas and battery voltages.

On the analytical approach for modeling photovoltaic systems behavior

The 1-diode/2-resistors electric circuit equivalent to a photovoltaic system is analyzed. The equations at particular points of the I–V curve are studied considering the maximum number of terms. The maximum power point as a boundary condition is given special attention. A new analytical method is developed based on a reduced amount of information, consisting in the normal manufacturer data. Results indicate that this new method is faster than numerical methods and has similar (or better) accuracy than other existing methods, numerical or analytical.

A method to obtain the thermal parameters and the photothermal transduction efficiency in an optical hyperthermia device based on laser irradiation of gold nanoparticles

Optical hyperthermia systems based on the laser irradiation of gold nanorods seem to be a promising tool in the development of therapies against cancer. After a proof of concept in which the authors demonstrated the efficiency of this kind of systems, a modeling process based on an equivalent thermal-electric circuit has been carried out to determine the thermal parameters of the system and an energy balance obtained from the time-dependent heating and cooling temperature curves of the irradiated samples in order to obtain the photothermal transduction efficiency. By knowing this parameter, it is possible to increase the effectiveness of the treatments, thanks to the possibility of predicting the response of the device depending on the working configuration. As an example, the thermal behavior of two different kinds of nanoparticles is compared. The results show that, under identical conditions, the use of PEGylated gold nanorods allows for a more efficient heating compared with bare nanorods, and therefore, it results in a more effective therapy.

Using an analytical model to design liquid crystal microlenses

We have developed new analytical expressions for designing liquid crystal (LC) microlenses. These equations are based on a novel equivalent electric circuit and can be used to create an optimum design for the LC lenses in which the lens diameter ranges from a few micrometers to several millimeters. Thus far, only experimental studies have been conducted on the LC lenses. The analytical expressions developed in this letter depend on various manufacturing parameters and can be used to design lenses with specific focal lengths and a parabolic phase profile. The required driving scheme (modal or hole-patterned) can be predicted. The LC microlenses were manufactured and electrooptically characterized: the measurements were compared using an analytical approach.

(Table 1) Air-earth current density investigated during Atlantic Expedition 1973 of METEOR

One main point of our atmospheric-electric measurements over the Atlantic Ocean 1973 was the investigation of the air-earth current density above the sea. In addition to direct measurements at the water surface with a floating net, we calculated the air-earth current density from the electric field and the air conductivity measured simultaneously on board of the ship and during particular ascents in the free atmosphere. During all five ascents the air-earth current density did not change with altitude. For pure maritime air-conditions, the mean air-earth current density was found to be 2.9 pA/m**2. The mean hourly air-earth current density over the Atlantic shows nearly the same 24-hour pattern as measured by Cobb (1977) at the South Pole at the same time. When dust-loaden air masses of African origin reached the ship as well as under continental influence the mean air-earth current density was reduced to 2.1 pA/m**2. The global 24-hour pattern was modified by this continental influences. Finally, it is shown that the values of the air conductivity measured on board R. V. "Meteor" during our earlier expeditions have been influenced by the exhaust of the ship and must therefore be corrected. With this correction, our new mean values of the air-earth current density over the Atlantic are 2.6 pA/m**2 in 1965 and 2.0 pA/m**2 in 1969. From all measurements, the global air-earth current is estimated to be about 1250 A.

Ground-fault protection on construction sites.

"1992 (Reprinted)."

The DRAGON users' manual by Peter Watterberg, Virginia Lo.

Bibliography: p. 35.

Guidelines for the installation of MSHA accepted ground wire monitors /

"July 1996."