12,709 research outputs found
Study of space cabin atmospheres Semiannual status report, 1 Jul. - 31 Dec. 1965
Space cabin atmospheres - space cabin aerosol sampling device, field aerosol generator, and survey of particle counter design
Respiratory protective device design using control system techniques
The feasibility of a control system analysis approach to provide a design base for respiratory protective devices is considered. A system design approach requires that all functions and components of the system be mathematically identified in a model of the RPD. The mathematical notations describe the operation of the components as closely as possible. The individual component mathematical descriptions are then combined to describe the complete RPD. Finally, analysis of the mathematical notation by control system theory is used to derive compensating component values that force the system to operate in a stable and predictable manner
Study of space cabin atmospheres Status report, Jul. 1 - Dec. 31, 1967
Calibration of hot-wire detector for particle concentration and size distribution in closed spacecraft cabin atmosphere
Study of Space Cabin Atmospheres Status Report, 1 Jan. - 30 Jun. 1966
Performance characteristics of aerosol generator, and distribution sampling errors of electrostatic precipitator sampling device for space cabin atmospher
Inflating in a Trough: Single-Field Effective Theory from Multiple-Field Curved Valleys
We examine the motion of light fields near the bottom of a potential valley
in a multi-dimensional field space. In the case of two fields we identify three
general scales, all of which must be large in order to justify an effective
low-energy approximation involving only the light field, . (Typically
only one of these -- the mass of the heavy field transverse to the trough -- is
used in the literature when justifying the truncation of heavy fields.) We
explicitly compute the resulting effective field theory, which has the form of
a model, with , as a function of these
scales. This gives the leading ways each scale contributes to any low-energy
dynamics, including (but not restricted to) those relevant for cosmology. We
check our results with the special case of a homogeneous roll near the valley
floor, placing into a broader context recent cosmological calculations that
show how the truncation approximation can fail. By casting our results
covariantly in field space, we provide a geometrical criterion for
model-builders to decide whether or not the single-field and/or the truncation
approximation is justified, identify its leading deviations, and to efficiently
extract cosmological predictions.Comment: 28 pages + 3 appendices, references added and typos corrected,
matches published versio
Operational experience and design recommendations for teleoperated flight hardware
Teleoperation (remote manipulation) will someday supplement/minimize astronaut extravehicular activity in space to perform such tasks as satellite servicing and repair, and space station construction and servicing. This technology is being investigated by NASA with teleoperation of two space-related tasks having been demonstrated at the Oak Ridge National Lab. The teleoperator experiments are discussed and the results of these experiments are summarized. The related equipment design recommendations are also presented. In addition, a general discussion of equipment design for teleoperation is also presented
Determining trip and travel mode from GPS and accelerometer data
Indiana University-Purdue University Indianapolis (IUPUI)The use of Global Positioning Systems (GPS) and/or accelerometers to identify
trips and transportation modes such as walking, running, bicycling or motorized
transportation has been an active goal in multiple disciplines such as Transportation
Engineering, Computer Science, Informatics and Public Health. The purpose of this
study was to review existing methods that determined trip and travel mode from raw
Global Positioning System (GPS) and accelerometer data, and test a select group of
these methods. The study had three specific aims: (1) Create a systematic review of
existing literature that explored various methods for determining trip and travel mode
from GPS and/or accelerometer data, (2) Collect a convenience sample of subjects who
were assigned a GPS and accelerometer unit to wear while performing and logging
travel bouts consisting of walking, running, bicycling and driving, (3) Replicate selected
method designs extracted from the systematic review (aim 1) and use subject data (aim
2) to compare the methods. The results were be used to examine which methods are
effective for various modes of travel
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