39,499 research outputs found
An Altitude Chamber for the Study and Calibration of Aeronautical Instruments
The design and construction of an altitude chamber, in which both pressure and temperature can be varied independently, was carried out by the NACA at the Langley Memorial Aeronautical Laboratory for the purpose of studying the effects of temperature and pressure on aeronautical research instruments. Temperatures from +20c to -50c are obtained by the expansion of CO2from standard containers. The chamber can be used for the calibration of research instruments under altitude conditions simulating those up to 45,000 feet. Results obtained with this chamber have a direct application in the design and calibration of instruments used in free flight research
Tumor stiffness extends its grip on the metastatic microenvironment
The increased stiffness of a tumor triggers a multitude of responses that aid cancer cell dissemination. Stiffness-induced expression of CCN1 mediates autocrine signaling in the endothelium to upregulate N-Cadherin levels. This permits more stable interactions with cancer cells and increases their ability to spread into the circulation
MalLo March: A Live Sonified Performance With User Interaction
Presented at the 22nd International Conference on Auditory Display (ICAD-2016)In this extended abstract we present a new performance piece titled MalLo March that uses MalLo, a predictive percussion instrument, to allow for real-time sonification of live performers. The piece consists of two movements where in the first movement audience members will use a web application and headphones to listen to a sonification of MalLo instruments as they are played live on stage. During the second movement each audience member will use an interface in the web app to design their own sonification of the instruments to create a personalized version of the performance. We present an overview of the hardware and interaction design, highlighting various listening modes that provide audience members with different levels of control in designing the sonification of the live performers
The NACA Three Component Accelerometer
A new instrument known as the NACA three component accelerometer is described in this note. This instrument was designed by the technical staff of the NACA for recording accelerations along three mutually perpendicular axes, and is of the same type as the NACA single component accelerometer with the addition of two springs and a few minor improvements such as a pump for filling the dash-pots and a convenient method for aligning the springs. This note includes a few records as well as photographs of the instrument itself
The N.A.C.A. Recording Tachometer and Angle of Attack Recorder
This note contains photos and descriptions of airplane flight apparatus for use in conjunction with a recording galvanometer. In measuring the angle of attack a variable resistance is used, being controlled by a vane in the airstream. Thus it is only necessary to measure the change of resistance
The distance to NGC 6397 by M-subdwarf main-sequence fitting
Recent years have seen a substantial improvement both in photometry of low
luminosity stars in globular clusters and in modelling the stellar atmospheres
of late-type dwarfs. We build on these observational and theoretical advances
in undertaking the first determination of the distance to a globular cluster by
main-sequence fitting using stars on the lower main sequence. The calibrating
stars are extreme M subdwarfs, as classified by Gizis (1997), with parallaxes
measured to a precision of better than 10%. Matching against King et al's
(1998) deep (V, (V-I)) photometry of NGC 6397, and adopting E_{B-V}=0.18 mag,
we derive a true distance modulus of 12.13 +- 0.15 mag for the cluster. This
compares with (m-M)_0=12.24 +- 0.1 derived through conventional main-sequence
fitting in the (V, (B-V)) plane. Allowing for intrinsic differences due to
chemical composition, we derive a relative distance modulus of delta
(m-M)_0=2.58 mag between NGC 6397 and the fiducial metal-poor cluster M92. We
extend this calibration to other metal-poor clusters, and examine the resulting
RR Lyrae (M_V, [Fe/H]) relation.Comment: 19 pages, AASTeX, to appear in the December 1998 A
Conical scan tracking system employing a large antenna
A conical scan tracking system for tracking spacecraft and distant radio sources is described. The system detects small sinusoidal modulation in received power from a source that is off target with a frequency equal to a very low scan rate, an amplitude proportional to angular deviation of the source from the target, and a phase directly related to the direction the source is off target. The sinusoid is digitally correlated with inphase and out-of-phase scan sinusoids to obtain azimuth/elevation and hour angle/declination signals which are digitally integrated over exactly one scan period to obtain correction signals for an antenna pointing subsystem
Conical-scan tracking with the 64-m-diameter antenna at goldstone
The theory and experimental work which demonstrated the feasibility of conical-scan tracking with a 64 m diameter paraboloid antenna is documented. The purpose of this scheme is to actively track spacecraft and radio sources continuously with an accuracy superior to that obtained by manual correction of the computer driven pointing. The conical-scan implementation gives increased tracking accuracy with X-band spacecraft signals, as demonstrated in the Mariner Venus/Mercury 1973 mission. Also, the high accuracy and ease of measurement with conical-scan tracking allow evaluation of systematic and random antenna tracking errors
The geography of strain: organizational resilience as a function of intergroup relations
Organizational resilience is an organization’s ability to absorb strain and preserve or
improve functioning, despite the presence of adversity. In existing scholarship there is
the implicit assumption that organizations experience and respond holistically to acute
forms of adversity. We challenge this assumption by theorizing about how adversity can
create differential strain, affecting parts of an organization rather than the whole. We
argue that relations among those parts fundamentally shape organizational resilience.
We develop a theoretical model that maps how the differentiated emergence of strain in
focal parts of an organization triggers the movements of adjoining parts to provide or
withhold resources necessary for the focal parts to adapt effectively. Drawing on core
principles of theories about intergroup relations, we theorize about three specific
pathways—integration, disavowal, and reclamation—by which responses of adjoining
parts to focal part strain shape organizational resilience. We further theorize about
influences on whether and when adjoining parts are likely to select different pathways.
The resulting theory reveals how the social processes among parts of organizations
influence member responses to adversity and, ultimately, organizational resilience. We
conclude by noting the implications for organizational resilience theory, research, and
practice.Accepted manuscrip
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