Tunable sensor response by voltage-control in biomimetic hair flow sensors

We present an overview of improvements in detection limit and responsivity of our biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors improves the responsively by up to 80% for flow signals at frequencies below the sensor’s resonance. Application of frequency matched AC-bias voltages allows for tunable filtering and selective gain up to 20 dB. Furthermore, the quality and fidelity of low frequency flow measurements can be improved using a non frequency-matched AC-bias voltage, resulting in a flow detection limit down to 5 mm/s at low (30 Hz) frequencies. The merits and applicability of the three methods are discussed

Het present van Staat : de gouden ketens, kettingen en medailles verleend door de Staten-Generaal, 1588-1795

Van 1588 tot 1795 vormden de Nederlanden een republiek van zeven soevereine gewesten In de vergadering van de Staten-Generaal in Den Haag overlegden vertegenwoordigers van de gewesten over zaken van algemeen belang, zoals de gemeenschappelijke landsverdediging en de buitenlandse politiek. Uit naam van de Republiek gaven de Staten-Generaal presenten en vereringen. Aan buitenlandse gezanten die op het punt stonden de Republiek te verlaten, aan brengers van belangrijke berichten en aan dappere soldaten en zeelieden. Er werden verschillende soorten voorwerpen als geschenk gegeven: kostbare tapijten, vaatwerk van goud of zilver, boeken, paarden en zelfs schelpen. Na 1630 werden de gouden ketting, de gouden medaille of de combinatie van beide het standaardgeschenk. Op den duur sprak men van het ‘ordinaris present’. Het present van Staat beschrijft hoe dit ordinaris present ontstond, op welke wijze en aan wie het werd verleend en toont er prachtige voorbeelden van.LEI Universiteit LeidenCollective identities and transnational networks in medieval and early modern Europe, 1000-180

Thin, flexible, capacitive force sensors based on anisotropy in 3D-printed structures

Conductive 3D-printed structures made out of a carbon doped thermoplastic polyurethane (TPU) deposited by an FDM 3D-printer show a high inter-layer contact resistance. Due to this poor resistive coupling capacitive effects between layers become prominent. This effect can be used to create capacitive force sensors by depositing only two thin layers of material. In this paper we investigate the feasibility of such a 3D-printed force sensor. The change in capacitance due to the compression of the material caused by an applied force (0 N to 10 N) is measured using an LCR meter. The presented sensor con- cept has a high potential for implementation in biomedical and soft robotic applications since the sensor is thin and flexible because it is made from soft material

Compact Micro-Coriolis Mass-Flow Meter with Optical Readout

This paper presents the first nickel-plated micro-Coriolis mass-flow sensor with integrated optical readout. The sensor consists of a freely suspended tube made of electroplated nickel with a total length of 60 mm, an inner diameter of 580 µm, and a wall thickness of approximately 8 µm. The U-shaped tube is actuated by Lorentz forces. An optical readout consisting of two LEDs and two phototransistors is used to detect the tube motion. Mass-flow measurements were performed at room temperature with water and isopropyl alcohol for flows up to 200 g/h and 100 g/h, respectively. The measured resonance frequencies were 1.67 kHz and 738 Hz for water and 1.70 kHz and 752 Hz for isopropyl alcohol for the twist and swing modes, respectively. The measured phase shift between the two readout signals shows a linear response to mass flow with very similar sensitivities for water and isopropyl alcohol of (Formula presented.) and (Formula presented.), respectively.</p

Modeling, Fabrication, and Testing of a 3D-Printed Coriolis Mass Flow Sensor

This paper presents the modeling, fabrication, and testing of a 3D-printed Coriolis mass flow sensor. The sensor contains a free-standing tube with a circular cross-section printed using the LCD 3D-printing technique. The tube has a total length of 42 mm, an inner diameter of about 900 µm, and a wall thickness of approximately 230 µm. The outer surface of the tube is metalized using a Cu plating process, resulting in a low electrical resistance of 0.5 Ω. The tube is brought into vibration using an AC current in combination with a magnetic field from a permanent magnet. The displacement of the tube is detected using a laser Doppler vibrometer (LDV) that is part of a Polytec MSA-600 microsystem analyzer. The Coriolis mass flow sensor has been tested over a flow range of 0–150 g/h for water, 0–38 g/h for isopropyl alcohol (IPA), and 0–50 g/h for nitrogen. The maximum flow rates of water and IPA resulted in less than a 30 mbar pressure drop. The pressure drop at the maximum flow rate of nitrogen is 250 mbar.</p