16,245 research outputs found
Metabolic simulation chamber
Metabolic simulation combustion chamber was developed as subsystem for breathing metabolic simulator. Entire system is used for evaluation of life support and resuscitation equipment. Metabolism subsystem simulates a human by consuming oxygen and producing carbon dioxide. Basic function is to simulate human metabolic range from rest to hard work
Temperature and humidity control of simulated human breath
Subsystem was developed for breathing metabolic simulator which adjusts temperature and humidity of air to levels of human exhaled breath. Temperature-humidity subsystem is described, consisting of aluminum enclosure with 400 watt heat sheet glued to bottom, vertical separators, inlet connection, and check valve
Simulated breath waveform control
Subsystem was developed which provides twelve waveform controls to breath drive mechanism. Twelve position, magnetically actuated rotary switch is connected to one end of crankshaft drive, such that it makes one complete revolution for each simulated breath. Connections with common wired point are included in modifications made to standard motor speed controller
A New Local Temperature Distribution Function for X-ray Clusters: Cosmological Applications
(abridged) We present a new determination of the local temperature function
of X-ray clusters. We use a new sample comprising fifty clusters for which
temperature information is now available, making it the largest complete sample
of its kind. It is therefore expected to significantly improve the estimation
of the temperature distribution function of moderately hot clusters. We find
that the resulting temperature function is higher than previous estimations,
but agrees well with the temperature distribution function inferred from the
BCS and RASS luminosity function. We have used this sample to constrain the
amplitude of the matter fluctuations on cluster's scale of
Mpc, assuming a mass-temperature relation based
on recent numerical simulations. We find for an
model. Our sample provides an ideal reference at to
use in the application of the cosmological test based on the evolution of X-ray
cluster abundance (Oukbir & Blanchard 1992, 1997). Using Henry's sample, we
find that the abundance of clusters at is significantly smaller, by
a factor larger than 2, which shows that the EMSS sample provides strong
evidence for evolution of the cluster abundance. A likelihood analysis leads to
a rather high value of the mean density parameter of the universe: (open case) and (flat case), which is
consistent with a previous, independent estimation based on the full EMSS
sample by Sadat et al.(1998). Some systematic uncertainties which could alter
this result are briefly discussed.Comment: 31 pages, 12 figures, mathches the version published in Astronomy and
Astrophysic
Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm
Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms
Breathing-metabolic simulator
Breathing-metabolic simulator was developed to be used for evaluation of life support equipment. Apparatus simulates human breathing rate and controls temperature and humidity of exhaled air as well as its chemical composition. All functions are designed to correspond to various degrees of human response
F-14 VSTFE and results of the cleanup flight test program
Flight transition data applicable to swept wings at high subsonic speeds are needed to make valid assessments of the potential for natural laminar flow or laminar flow control for transports of various sizes at various cruise speeds. NASA initiated the variable sweep transition flight experiment (VSTFE) to help establish a boundary layer transition data base for use in laminar flow wing design. The carrier vehicle for this experiment is an F-14, which has variable sweep capability. The variable sweep outer panels of the F-14 were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined. The VSTFE program is briefly described and some preliminary glove I flight results are presented
Enhanced vaccine control of epidemics in adaptive networks
We study vaccine control for disease spread on an adaptive network modeling
disease avoidance behavior. Control is implemented by adding Poisson
distributed vaccination of susceptibles. We show that vaccine control is much
more effective in adaptive networks than in static networks due to an
interaction between the adaptive network rewiring and the vaccine application.
Disease extinction rates using vaccination are computed, and orders of
magnitude less vaccine application is needed to drive the disease to extinction
in an adaptive network than in a static one
- …