We apply canonical Poisson-Lie T-duality transformations to bosonic open string worldsheet boundary conditions, showing that the form of these conditions is invariant at the classical level, and therefore they are compatible with Poisson-Lie T-duality. In particular the conditions for conformal invariance are automatically preserved, rendering also the dual model conformal. The boundary conditions are defined in terms of a gluing matrix which encodes the properties of D-branes, and we derive the duality map for this matrix. We demonstrate explicitly the implications of this map for D-branes in two non-Abelian Drinfel'd doubles.
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In this paper, a single-use and unidirectional microvalve with low consumption of energy for PCB-based microfluidic platforms is reported. Its activation is easy because it works as a fuse. The fabrication process of the device is based on PCB technology and a typical SU-8 process, using the PCB as a substrate and SU-8 for the microfluidic channels and chambers. The microvalve is intended to be used to impulse small volumes of fluids and it has been designed to be highly integrable in PCB-based microfluidic platforms. The proposed device has been fabricated, integrated and tested in a general purpose microfluidic circuit, resulting in a low activation time, of about 100 μs, and a low consumption of energy, with a maximum of 27 mJ. These results show a significant improvement because the energy consumption is about 84% lower and the time response is about four orders of magnitude shorter if compared with similar microvalves for impulsion of fluids on PCB-based platforms.
Both high sensitivity and good measurement accuracy are required in a metals continuous emissions monitor in order for it to be acceptable for compliance monitoring. An atmospheric plasma sustained by microwaves with an attached source of a calibrated trace metals aerosol has been shown to be capable of achieving both of these requirements. The microwave plasma is continuous and operates in undiluted stack exhaust for atomic emission spectroscopy of trace metals. The plasma is sustained in a shorted waveguide that is attached to the stack by a short sample line (< 50 cm). It is powered at 1.5 kW, at a frequency of 2.45 GHz. An undiluted stack slipstream is isokinetically drawn into the plasma by a suction pump at a nominal flow of 14 liters per minute. The pneumatic nebulizer attached to the sample line can momentarily, on command, inject a known concentration of metals solution providing a real-time span calibration. The system was tested on the exhaust stack of the rotary kiln incinerator simulator facility at the Environmental Protection Agency (EPA) National Risk Management Laboratory in Research Triangle Park. Three hazardous metals were monitored, lead, chromium, and beryllium. These measurements were referenced to EPA Method-29. A total of twenty spiked stack exhaust tests were carried out. Ten one-hour tests at high concentration (40-60 µg/actual m 3 ) and ten one and half-hour tests at low concentration (10-15 µg/actual m 3 ). The microwave plasma monitor achieved relative accuracies of approximately 20% for lead and beryllium and 40% for chromium with a threshold detection capability of < 3 µg/actual m 3 for a time response of ∼1-minute. The relative accuracy deviation from the EPA Method-29 was found to be mostly systematic. This suggests the possibility of using a site-specific calibration to bring the microwave plasma into compliance with EPA's goal of 20% relative accuracy to the reference method. Laboratory work is continuing to add mercury, arsenic, and cadmium to the monitored metals. Mercury and arsenic present a particular challenge to achieving high detection sensitivity in undiluted stack exhaust because the plasma is less efficient in exciting Hg and because UV absorption interferes with As detection. This is a problem that is also in common with air ICP and in situ spark plasma methods for continuous emissions monitoring of metals. INTRODUCTIONAdvancing the state-of-the-art of continuous emissions monitoring (CEM) technology for rapid and simultaneous detection of all hazardous metals in stack exhaust is currently the focus of significant development activity. Such a CEM must be able to monitor at a minimum six of the Resource Conservation and Recovery Act (RCRA) metals: arsenic, beryllium, cadmium, chromium, lead, and mercury. Detection limits on the order of 1µg/m 3 are needed with minimum accuracies of 20% relative to the current Environmental Protection Agency (EPA) reference method. In addition, the goal is to develop an instrument that is affordable, easy to use, low maintena...
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