1,721,395 research outputs found
High pressure gas-liquid mixtures generated in a micro-electrolysis cell
No full textIn this work a micro-electrolysis cell is presented that allows the rapid generation of high pressure gas-liquid mixtures. The stainless steel electrolysis cell (150 µl volume) is constructed as an integral part of an automotive pressure sensor, allowing the on-line monitoring of the generated pressure. By the application of an electric current between two platinum electrodes inserted in the electrolyte filled cell, hydrogen and oxygen gas was generated with pressures up to 1350 bar. First experiments were performed to investigate the catalytic back-reaction of the generated hydrogen/oxygen mixture at the surface of the platinum electrodes. By the application of a compensation current to keep the internal pressure at a constant value, the rate of the back reaction could be established. It follows that the catalytic back-reaction rate increases exponentially above a pressure of 800 bar. As the proposed method of in-situ high pressure gas generation is intrinsically fast and safe due to the small cell volume, a large number of these cells/reactors can form a platform for (chemical) high throughput experimentation (HTE)
Ultrasonic distance detection in spinal cord stimulation
Full text linkSpinal cord stimulation (SCS) is a clinical method for primarily the management of chronic, intractable pain. The method is based on electrical stimulation of nerve fibers in the posterior part of the spinal cord. An electric field is applied by an electrode array, implanted medially in the posterior epidural space, at some distance from the spinal cord. An implantable pulse generator provides the electrical stimulation pulses to the electrode array via a cable. When stimulating the spinal cord with pulses of constant amplitude, the current density in the spinal cord and thus the effects on nerve fibers will change with body position and/or posture, due to the varying distance between the spinal cord and the stimulating electrode array. As a result, the pain relieving effect may either vanish (when the distance is too large), or be dominated by uncomfortable sensations. To avoid these adverse conditions the current density in the spinal cord has to remain within a small window. In present SCS systems the stimulus applied by the electrode array is either set at a constant value, or the patient is allowed to select one out of only two preset pulse amplitudes. Therefore, a major improvement would be achieved if the distance between stimulation electrode array and spinal cord could be measured and used as a feedback signal to control the stimulus amplitude in a closed-loop system. Therefore, an ultrasonic distance detection system has been proposed to measure the distance between stimulation electrode array and the spinal cord. The ultrasonic system consists of a piezoelectric transducer and an echo detection circuit. To enable the design and optimization of the piezoelectric transducer an appropriate model description is needed
An integrated sensor system for monitoring washing processes
Full text linkThis thesis deals with the development, realisation and testing of an array of sensors for determining the state of a washing process. To combine the sensors in a single array, some techniques are used. First, the sensors which are integrated are chosen with respect to their fabrication materials and technique. By matching these, the sensors could be combined into a single multi-purpose structure. A reduction of the number of connecting wires is the result, and the single structure will measure all parameters at the same spot in the solution. In addition, together with sensors, also actuators are integrated. This enables the possibility of performing stimulus-response measurements. Such experiments are based on recording the response of solution components on an imposed local disturbance. Sometimes, such dynamic measurements give new information on the solution. Finally, the combination of sensor readings, together with the results of the stimulus-response measurements, yields a set of data which can be used for smart interpretation and decisions. The final result is a system consisting of a small noble metal structure, applied on a carrier, with a size of only one square millimetre. By scheduling this structure in several operational modes, the following washing parameters can be measured: temperature, bleach activity, electrolyte conductivity, movement of the washing water and the temperature dependency of the electrolyte conductivity. The latter one can give information on the individual types of charged particles in the solution. Finally, some suggestions are given in order to implement washing parameters that are missing in the measurable set of variables
A polymer condenser micorphone realised on silicon containing preprocessed integrated circuits
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sj-docx-1-eso-10.1177_23969873221145771 – Supplemental material for Association between type of intervention center and outcomes after endovascular treatment for acute ischemic stroke: Results from the MR CLEAN Registry
No full textSupplemental material, sj-docx-1-eso-10.1177_23969873221145771 for Association between type of intervention center and outcomes after endovascular treatment for acute ischemic stroke: Results from the MR CLEAN Registry by Susanne GH Olthuis, Wouter H Hinsenveld, Florentina ME Pinckaers, Marzyeh Amini, Hester F Lingsma, Julie Staals, Tobien HCML Schreuder, Wouter J Schonewille, Lonneke SF Yo, Yvo BWEM Roos, Alida A Postma, Diederik WJ Dippel, Wim H van Zwam, Robert J van Oostenbrugge and Inger R de Ridder in European Stroke Journal</p
Potentiometric detection and characterization of adsorbed protein using stimulus-response measurement techniques
No full textThe EMOSFET, A potentiometric transducer based on chemically induced work function changes of electrochemically active films
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