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Since the emergence of the MEMS industry, rapid prototyping became crucial to allow for efficiently testing new designs at low cost by small batches production and rapid fabrication technologies as conductive polymer [1], conductive inkjet [2] or sacrificial-layer-free fabrication processes [3]. In the same time, flexible electronics is becoming one of the main emerging topics in the electronics field. In this work, we are experiencing a new ultra-fast-prototyping dry process that enables to produce functionalized capacitive membrane arrays on Kapton®, from Dupont®, polyimide as flexible substrate in an only oneday process philosophy based on laser etching. The process consists in releasing membranes by a calibrated laser etch in a Kapton, on the top of which a thin metal layer has been deposited, and next bonding the sheet on a metal-coated Pyralux® sheet, also from Dupont, that will act as bottom electrode and flexible substrate (fig. 1). In this work, the active 52µm Kapton sheet features 16 membranes of 1mm diameter and 25µm remaining polyimide thickness. Characterization of the etch speed is done considering three parameters as presented in [4]: laser velocity, V, number of etch passes, N, and the proportion of the total laser power, P, merged together as an etch factor that is N.P/V, the total laser power being 3.5W Multiple tests have been done showing good linearity following the ratio between the number of passes and speed (fig. 2). Multiple runs have been performed showing low variation in terms of etch depth (

A definitory feature of MEMS devices is the coupling at microscale between multiple energy domains. Reduced order macro-models (ROM) can be built using either signal flow or energy flow paradigms. While easier conceptually, reducing the device to a dynamical system defined by a set of differential equations, the so-called causal signal flow paradigm is nevertheless less portable, because the macro-models embed as well the excitation, or boundary conditions. The energy flow paradigm, on the other side, is an acausal modeling methodology that reduces the physical system to an equivalent generalized, Spice-like, network, based on across-through (power complementary) variables. The circuit-like representation makes it easier to interface with read-out or actuation electronics systems, for complete microsystems design, simulation and optimization. Besides existing standard behavioral modeling languages like VHDL-AMS and Modelica, MathWorks Simscape language has evolved in the past years to the point where it offers an alternative for the implementation of advanced MEMS macro-models; its seamless interface with Matlab and Simulink offers a strong framework for developing complex hybrid microsystems models, that mix Simulink (signal flow) models with Simscape (energy flow) ones. We have built a generic Simscape library for parameterized MEMS pressure sensors for two distinct categories, piezoresistive and capacitive sensing. The behavior of Simscape macro-models (e.g. sensitivity and frequency response) was validated against models of the same devices extracted in Coventor MEMS+ (a dedicated software for the design and simulation of MEMS devices) and finite element analyses (FEA).

A crude hydromethanolic extract from Pinus brutia bark and its fractions (diethyl ether, ethyl acetate, n-butanol, and aqueous fractions) were studied with regard to their phenolic content and antioxidant activities. The total phenolics and proanthocyanidins in each extract were quantified by spectrophotometric methods the polyphenolic profile was analyzed by RP-HPLC-DAD-ESI-MS. All extracts were tested with regard to their ability to scavenge free radicals (ABTS radical cation, superoxide and hydroxyl radicals), reduce ferric ions, and inhibit 15-lipoxygenase. P. brutia bark extracts had high phenolic contents (303.79±7.34-448.90±1.39 mg/g). Except diethyl ether extract, all other extracts contained proanthocyanidins ranging from 225.79±3.94 to 250.40±1.44 mg/g. Several polyphenols were identified by RP-HPLC-DAD-ESI-MS: taxifolin in diethyl ether extract, a taxifolin-O-hexoside, catechin, procyanidin dimers, and trimers in ethyl acetate extract. Except diethyl ether extract, all other extracts were effective scavengers of superoxide and hydroxyl radicals (EC50=33.5±1.1-54. 93±2.85 μg/mL and 0.47±0.06-0.6±0.0 mg/mL, respectively). All extracts had noticeable 15-lipoxygenase inhibitory effects (EC50=22.47±0.75-34.43±2.25 μg/mL). We conclude that P. brutia bark is very promising for the dietary supplements industry due to its high free radical scavenging and 15-lipoxygenase inhibitory effects. © 2013 Mary Ann Liebert, Inc., and Korean Society of Food Science and Nutrition. 16 984 991 Cited By :7

In this paper we present a method for closed-loop operation of pull-in time accelerometers. Accelerometers based on the measurement of the pull-in time of movable parallel-plates MEMS structures have already demonstrated very good resolution capabilities, with low requirements on the capacitive readout. However, open-loop operation delivers very low dynamic range and highly non-linear response. The closed-loop approach relies on electrostatic feedback using counter-actuation electrodes opposite to the pull-in direction and although the control algorithm used was very simple, the dynamic range has been effectively extended and the linearity improved., Fundação para a Ciência e a Tecnologia (FCT)

Pull-in time based accelerometers present very high resolutions. One of its most important features is the detection capability bottleneck due to the MEMS structure thermalmechanical noise rather than the measurement/transduction mechanism. A study of the intervenient noise sources is presented in this paper. MEMS structures fabricated on the SOIMUMPs process were used and a relatively high noise was measured, which, considering the analysis performed, was attributed to environmental vibrations that should be prevented in future experiments. The analysis supports the low-noise characteristics of the pull-in time accelerometer., Fundação para a Ciência e a Tecnologia (FCT)

The pull-in time of electrostatically actuated parallel-plate microstructures enables the realization of a high-sensitivity accelerometer that uses time measurement as the transduction mechanism. The key feature is the existence of a metastable region that dominates pull-in behavior, thus making pull-in time very sensitive to external accelerations. Parallel-plate MEMS structures have been designed and fabricated using a SOI micromachining process (SOIMUMPS) for the implementation of the accelerometer. This paper presents the experimental characterization of the microdevices that validates the concept and the analytical models used. The accelerometer has a measured resolution of 0.25 μs/μg and an estimated mechanical-thermal noise of 2.8 μg/VHz. Since the bandwidth of the sensor is directly related to the pull-in time (BW = 2/tpi = 180 Hz), the total measured noise floor of 400 μg (110 μs) suggests that the main noise source comes from the building vibrations.

A local smart bus is described which is designed for use in muti-chip-composed microinstrumentation system. The bus is able to transmit a digital code, bitstream, analog voltage, frquency, duty-cycle and also provides calibration facilities, service request and interrupt request modes., FCT

A flexible architecture for a microinstru- mentation system in silicon was developped, and intended for use in a wide range of applications. The MCM device should be considered a genuine (micro)instrument, which supplies high-level data over an external instrumentation bus. Internally, the system should support all vital functions, such as power management, self-calibration and in-system data transfer over a flexible internal data bus. The internal bus is the major subject of this paper. Drivers are designed for a generic sensor module; the application will decide the type of sensors to be used., STW - Project DEL55.3733. TU Delft. Junta Nacional de Investigação Científica e Tecnológica - PRAXIS XXI-BD/5181/95.

A local bus is described which is designed for use in a multi-chipcomposed microinstrumentation system. The bus is able to transmit a digital code, bitstream, analog voltage, frequency, duty-cycle and also provides calibration facilities, service request and interrupt request for the smart sensors. Corresponding sensor bus interface was implemented in a 1.6 m CMOS process and successfully tested in a local sensor network., Junta Nacional de Investigação Científica e Tecnológica - Praxis XXI-BD/5181/95. STW - Project DEL 55.3733. TUDelft.

Comunicação apresentada na 23rd European Solid-State Circuits Conference (ESSCIRC '97), Southampton, UK, 16-18 September 1997., This paper describes a digital local bus interface, which is designed for use in a multi-chip-composed microsystem. The chip area using a CMOS 1.6mm n-well technology is 1mm2. Power consumption at 5V@100kHz is less than 500mW and for 5V@4MHz less than 2mW due to a smart power management of all functional blocks. The bus interface is able to transmit a digital code, bitstream, analog voltage, frequency, duty-cycle and also provides calibration facilities, service request and interrupt request for the smart sensors or microactuators., Junta Nacional de Investigação Científica e Tecnológica - Praxis XXI-BD/5181/95. STW - Project DEL 55.3733. TUDelft.

This paper describes the development of a microinstrumentation system in silicon containing all the components of the data acquisition system, such as sensors, signal-conditioning circuits, analog-digital converter, interface circuits, sensor bus interface, and an embedded microcontroller (MCU). The microinstrumentation system is to be fabricated using the Multi-Chip-Module (MCM) technology based on a chip-level infrastructure. A standard silicon platform is the floorplan for individual smart sensor die attachment and an on-chip local sensor bus interface, testing facilities, optional compatible sensors (such as thermal sensors). The microinstrumentation system is controlled by a MCU with several modes of low-power operation (inclusive stand-by mode). As the intended application requires a huge amount of data-processing, a RISC-type MCU architecture is to be used. The MCU communicates with the front-end sensors via a two-line (clock and data lines) intramodule sensor bus (Integrated Smart Sensor bus). The sensor scan rate is adaptive and can be event triggered. This upgraded version of the ISS bus allows: service and interrupt request from the sensors, test and calibration facilities. However, the additional functionality requires a third line. The MCU also controls the power consumption and the thermal budget of all system. This paper also presents three applications for the microinstrumentation system: condition monitoring of machines, an inertial navigation system and a miniature spectrometer., STW - Project DEL55.3733. TUDelft. Junta Nacional de Investigação Científica e Tecnológica - Praxis XXI-BD/5181/95.