Dynamic measurement of gas flow using acoustic resonance tracking.

The National Institute of Standards and Technology measured gas flows exiting large, unthermostated, gas-filled, pressure vessels by tracking the time-dependent pressure P(t) and resonance frequency f(t) of an acoustic mode N of the gas remaining in each vessel. This is a proof-of-principle demonstration of a gas flow standard that uses P(t), f(t), and known values of the gas's speed of sound w(p,T) to determine a mode-weighted average temperature ⟨T⟩ of the gas remaining in a pressure vessel while the vessel acts as a calibrated source of gas flow. To track f(t) while flow work rapidly changed the gas's temperature, we sustained the gas's oscillations using positive feedback.

Modeling temperature effects on a Coriolis mass flowmeter.

Coriolis mass flowmeters are used for many applications, including as transfer standards for proficiency testing and liquified natural gas (LNG) custody transfer. We developed a model to explain the temperature dependence of a Coriolis meter down to cryogenic temperatures. As a first step, we tested our model over the narrow temperature range of 285 K to 318 K in this work.

Progress Towards a Gas-Flow Standard using Microwave and Acoustic Resonances.

We describe our progress in developing a novel gas flow standard that utilizes 1) microwave resonances to measure the volume, and 2) acoustic resonances to measure the average gas density of a collection tank / pressure vessel. The collection tank is a 1.85 m, nearly-spherical, steel vessel used at pressures up to 7 MPa.

Hydrogen Field Test Standard: Laboratory and Field Performance.

The National Institute of Standards and Technology (NIST) developed a prototype field test standard (FTS) that incorporates three test methods that could be used by state weights and measures inspectors to periodically verify the accuracy of retail hydrogen dispensers, much as gasoline dispensers are tested today. The three field test methods are: 1) gravimetric, 2) Pressure, Volume, Temperature (), and 3) master meter. The FTS was tested in NIST's Transient Flow Facility with helium gas and in the field at a hydrogen dispenser location.

Synaptic pathology and therapeutic repair in adult retinoschisis mouse by AAV-RS1 transfer.

Strategies aimed at invoking synaptic plasticity have therapeutic potential for several neurological conditions. The human retinal synaptic disease X-linked retinoschisis (XLRS) is characterized by impaired visual signal transmission through the retina and progressive visual acuity loss, and mice lacking retinoschisin (RS1) recapitulate human disease. Here, we demonstrate that restoration of RS1 via retina-specific delivery of adeno-associated virus type 8-RS1 (AAV8-RS1) vector rescues molecular pathology at the photoreceptor-depolarizing bipolar cell (photoreceptor-DBC) synapse and restores function in adult Rs1-KO animals.