178 research outputs found
Flow direction measurement with fixed probes
Fixed-position probes for determination of flow direction in one and two planes are tested over a wide range of Reynolds numbers and Mach numbers. The work is limited to tests of a single probe design for two dimensional flow and a single design for three dimensional flow
NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0014
The data currently available from GASP, including flight routes and dates, instrumentation, data processing procedures, and data tape specifications are described. Measurements of atmospheric ozone, cabin ozine, carbon monoxide, water vapor, particles, clouds, condensation nuclei, filter samples and related meteorological and flight information obtained during 562 flights of aircraft N533PA, N4711U, N655PA, and VH-EBE from October 3, 1977 through January 5, 1978 are reported. Data representing tropopause pressures obtained from time and space interpolation of National Meteorological Center archived data for the dates of the flights are included
Total-pressure measurement in pulsating flows
Pneumatic-type probe was used as comparison instrument with total pressure tubes to determine true average pressure and, thus, to determine if nonlinear averaging effects were significant. Since pneumatic probe is more complicated to use than a total-pressure tube, it is used only as a comparison instrument to determine extent of averaging effects
NASA Global Atmospheric Sampling Program (GASP) data report for tapes VL0010 and VL0012
The GASP atmospheric trace constituent data currently available are considered. Included on tapes are in-situ measurements of atmospheric ozone, carbon monoxide, water vapor, and clouds, data from laboratory analysis of filters exposed in flight, and related flight and meteorological data. Measurements of ozone levels within the first class cabin of these aircraft are also reported. In addition to the GASP data, tropopause pressures obtained from time and space interpolation of NMC archived data for the dates of the flights are included. Reported herein are the flight routes and dates, instrumentation, data processing procedures, data tape specifications, and analyses of the cabin ozone measurements
NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0009
The GASP atmospheric trace constituent data cover atmospheric ozone, carbon monoxide, condensation nuclei, clouds, and related meteorological and flight information obtained during October 28-31, 1977. Reported herein are flight routes and dates, instrumentation, data processing procedures, and data tape specifications
Venturi meter with separable diffuser
The diffuser and nozzle of venturi meters are made as separate pieces for easier fabrication. Venturi meter efficiency is affected by the diffuser inlet diameter being greater than two percent larger than the throat diameter, by Reynolds number and by Mach number
A multielement probe for coincident temperature and pressure measurements
Small, multielement probes are described which measure total pressure and temperature coincidentally at one or several points in gas stream
Competition for finite resources
The resources in a cell are finite, which implies that the various components
of the cell must compete for resources. One such resource is the ribosomes used
during translation to create proteins. Motivated by this example, we explore
this competition by connecting two totally asymmetric simple exclusion
processes (TASEPs) to a finite pool of particles. Expanding on our previous
work, we focus on the effects on the density and current of having different
entry and exit rates.Comment: 15 pages, 9 figures, v2: minor revisions, v3: additional reference &
minor correction
Slowest relaxation mode of the partially asymmetric exclusion process with open boundaries
We analyze the Bethe ansatz equations describing the complete spectrum of the
transition matrix of the partially asymmetric exclusion process on a finite
lattice and with the most general open boundary conditions. We extend results
obtained recently for totally asymmetric diffusion [J. de Gier and F.H.L.
Essler, J. Stat. Mech. P12011 (2006)] to the case of partial symmetry. We
determine the finite-size scaling of the spectral gap, which characterizes the
approach to stationarity at large times, in the low and high density regimes
and on the coexistence line. We observe boundary induced crossovers and discuss
possible interpretations of our results in terms of effective domain wall
theories.Comment: 30 pages, 9 figures, typeset for pdflatex; revised versio
Power Spectra of a Constrained Totally Asymmetric Simple Exclusion Process
To synthesize proteins in a cell, an mRNA has to work with a finite pool of
ribosomes. When this constraint is included in the modeling by a totally
asymmetric simple exclusion process (TASEP), non-trivial consequences emerge.
Here, we consider its effects on the power spectrum of the total occupancy,
through Monte Carlo simulations and analytical methods. New features, such as
dramatic suppressions at low frequencies, are discovered. We formulate a theory
based on a linearized Langevin equation with discrete space and time. The good
agreement between its predictions and simulation results provides some insight
into the effects of finite resoures on a TASEP.Comment: 4 pages, 2 figures v2: formatting change
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