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Accurate gas properties are needed to take full advantage of the low uncertainties provided by NISTs Gas Flow Calibration Services. If a flowmeter user and NIST use different values for these properties (molecular mass, compressibility, density, viscosity
We present a technique to induce temperature gradients in flexible microfluidic devices with microwave energy. Microwave power decays exponentially in the propagating medium, and the rate of decay is higher for water compared to polymers or glass due to
A nanofluidic approach to the separation and metrology of nanoparticles is demonstrated. Advantages of this approach include nanometer-scale resolution, nanometer-scale to submicrometer-scale range, mitigation of hydrodynamic and diffusional limitations to
In this paper, the piezoelectric ceramics mounted on the endplates of a cylindrical resonator were used as the source and detector for acoustic speed measurements. The perturbations of the longitudinal gas modes of the cavity due to the compliance of the
James C. Booth, Nathan D. Orloff, Xiaoli Lu, Yu Y. Wang, Eduard Rocas, Jordi Mateu, Juan C. Collado Gomez, Michael D. Janezic
We describe the development of coplanar waveguide measurement structures integrated with microfluidic channels in order to rapidly determine the broadband dielectric properties of nanoliter volumes of fluids, fluid mixtures, and colloids over the range of
James R. Baker-Jarvis, Sung Kim, Luke Leschallinger, Justin Johnson, Brad Givot
The purpose of this report is to summarize the characterization of a number of high-frequency solid, liquid, and semisolid tissue-equivalent materials, from 200 MHz to 20 GHz. Carbon black and liquid mixtures were studied, but were found to be unsuitable
Keith A. Gillis, Daniel K. Havey, Joseph T. Hodges
We model and measure the absolute response of an intensity-modulated photoacoustic spectrometer comprising a 10 cm long resonator and having a Q-factor of approximately 30. We present a detailed theoretical analysis of the system and predict its response
We combine accurate ab initio calculations of the second and third density virial coefficients, B(T) and C(T), of 4He with measurements of its pressure-density-temperature behavior to determine the fourth density viral coefficient D(T). The measurements
Akin Akturk, M. Holloway, S. Potbhare, David J. Gundlach, B Li, Neil Goldsman, M Peckerar, Kin P. Cheung
We have developed compact and physics-based distributed numerical models for cryogenic bulkMOSFET operation down to 20 K to advance simulation and first-pass design of device and circuit operation at low temperatures. To achieve this, we measured and
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates m dot of water "dynamically," that is from the time derivative of the weight W of the collection tank: m dot,dynamic = (dW/dt)/g. When data for a
Mu Hong Lin, Peter E. Bradley, Marcia L. Huber, Ryan J. Lewis, Ray Radebaugh, Yung-Cheng Lee
Optimized mixed refrigerants are applied in Joule-Thomson (JT) micro cryogenic coolers (MCC) to enhance efficiency. Mixed refrigerants deliver equivalent refrigeration power with much lower pressure ratio and flow rate compared to pure nitrogen refrigerant