59,416 research outputs found
Three-dimensional pantograph for use in hazardous environments
Material measurement device is used with radioactive probes which can be approached only to distance of 3 feet. Tracer-following unit is capable of precisely controlled movement in X-Y-Z planes. Pantograph is usable in industrial processes involving chemical corrosives, poisons, and bacteriological hazards, as well as nuclear applications
Geodynamics and temporal variations in the gravity field
Just as the Earth's surface deforms tectonically, so too does the gravity field evolve with time. Now that precise geodesy is yielding observations of these deformations it is important that concomitant, temporal changes in the gravity field be monitored. Although these temporal changes are minute they are observable: changes in the J2 component of the gravity field were inferred from satellite (LAGEOS) tracking data; changes in other components of the gravity field would likely be detected by Geopotential Research Mission (GRM), a proposed but unapproved NASA gravity field mission. Satellite gradiometers were also proposed for high-precision gravity field mapping. Using simple models of geodynamic processes such as viscous postglacial rebound of the solid Earth, great subduction zone earthquakes and seasonal glacial mass fluctuations, we predict temporal changes in gravity gradients at spacecraft altitudes. It was found that these proposed gravity gradient satellite missions should have sensitivities equal to or better than 10(exp -4) E in order to reliably detect these changes. It was also found that satellite altimetry yields little promise of useful detection of time variations in gravity
Droplet detachment and bead formation in visco-elastic fluids
The presence of a very small amount of high molecular weight polymer
significantly delays the pinch-off singularity of a drop of water falling from
a faucet, and leads to the formation of a long-lived cylindrical filament. In
this paper we present experiments, numerical simulations, and theory which
examines the pinch-off process in the presence of polymers. The numerical
simulations are found to be in excellent agreement with experiment. As a test
case, we establish the conditions under which a small bead remains on the
filament; we find that this is due to the asymmetry induced by the self-similar
pinch-off of the droplet.Comment: 4 pages, 4 figure
Analysis of supersonic conical flows
Method of characteristics analytical technique for flow predictions of supersonic cross flows over conical bodie
Manned simulations of the SRMS in SIMFAC
SIMFAC is a general purpose real-time simulation facility currently configured with an Orbiter-like Crew Compartment and a Displays and Controls (D and C) Subsystem to support the engineering developments of the Space Shuttle Remote Manipulator (SRMS). The simulation consists of a software model of the anthropomorphic SRMS manipulator arm including the characteristics of its control system and joint drive modules. The following are discussed: (1) simulation and scene generation subsystems; (2) the SRMS task in SIMFAC; (3) operator tactics and options; (4) workload; (5) operator errors and sources; (6) areas for further work; and (7) general observations
The AdHOC study of older adults’ adherence to medication in 11 countries
BACKGROUND: Compared with the resources expended developing, evaluating
and making clinical decisions about prescribing medication, we know little about
what determines whether people take it. Older adults are prescribed more
medication than any other group. Poor adherence is a common reason for nonresponse
to medication.
OBJECTIVES: To investigate cross-nationally the impact of demographic,
psychiatric (including cognitive), physical health, behavioural and medication factors
on adherence to medication in older adults.
METHODS: Researchers interviewed 3881 people over 65 who receive home
care services using a structured interview at participants’ places of residence in
eleven countries. The main outcome measure was the percentage participants not
adherent to medication.
RESULTS: 12.5% (n= 456) of people reported they were not fully adherent to
medication. Non-adherence was predicted by problem drinking (OR=3.6), not having
a doctor review medication (OR=3.3), dementia (OR=1.4 for every one point
increase in impairment), good physical health (OR=1.2), resisting care (OR=2.1)
being married (OR=2.3) and living in the Czech Republic (OR=4.7) or Germany
(OR=1.4).
CONCLUSION: People, who screen positive for problem drinking and with
dementia, often undiagnosed are less likely to adhere to medication. Therefore
doctors should consider dementia and problem drinking when prescribing for older
adults. Interventions to improve adherence in older adults might be more effective if
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targeted at these groups. It is possible that medication review enhances adherence,
by improving the patient-doctor relationship, or by emphasising the relevance of
medications
Experimental studies of hypersonic boundary-layer transition and effects of wind tunnel disturbances
Boundary layer transition data on cones and free stream disturbance levels were measured in a hypersonic wind tunnel and Mach 8 variable density hypersonic tunnel. Transition data were obtained by using different conical models and techniques for detecting the location of transition. The disturbance levels were measured by using hot wire anemometry and pressure transducers. The transition Reynolds numbers obtained from the tests correlated well when the fluctuating pressures measured at the surface of conical models were used as a correlating parameter
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