5,232 research outputs found
Calibration of the LIGO displacement actuators via laser frequency modulation
We present a frequency modulation technique for calibration of the
displacement actuators of the LIGO 4-km-long interferometric gravitational-wave
detectors. With the interferometer locked in a single-arm configuration, we
modulate the frequency of the laser light, creating an effective length
variation that we calibrate by measuring the amplitude of the frequency
modulation. By simultaneously driving the voice coil actuators that control the
length of the arm cavity, we calibrate the voice coil actuation coefficient
with an estimated 1-sigma uncertainty of less than one percent. This technique
enables a force-free, single-step actuator calibration using a displacement
fiducial that is fundamentally different from those employed in other
calibration methods.Comment: 10 pages, 5 figures, submitted to Classical and Quantum Gravit
ΠΠ± ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΌΠ°ΡΡΠ½ΠΈΠΊΠ°, Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΡΡΡΠ΅Π³ΠΎ ΡΠΎ ΡΡΡΡΠ½ΠΎΠΉ
Π Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΠΈ Π½Π΅Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΠΏΠΎΡΡΠ°Π½ΠΎΠ²ΠΊΠ°Ρ
ΡΠ΅ΡΠ΅Π½Π° Π·Π°Π΄Π°ΡΠ° ΠΎΠ± ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΡΡ
Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΠΉ ΠΎΠ΄Π½ΠΎΠ·Π²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΌΠ°ΡΡΠ½ΠΈΠΊΠ° Π² Π³ΠΈΠ±ΡΠΈΠ΄Π½ΠΎΠΉ ΠΌΠΎΠ΄Π΅Π»ΠΈ ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ, ΡΠΎΡΡΠΎΡΡΠ΅ΠΉ ΠΈΠ· Π³ΠΎΡΠΈΠ·ΠΎΠ½ΡΠ°Π»ΡΠ½ΠΎ Π·Π°ΠΊΡΠ΅ΠΏΠ»Π΅Π½Π½ΠΎΠΉ ΡΡΡΡΠ½Ρ, Π½Π°Π³ΡΡΠΆΠ΅Π½Π½ΠΎΠΉ ΠΊΠΎΠ»Π΅Π±Π»ΡΡΠ΅ΠΉΡΡ ΡΠΎΡΡΠ΅Π΄ΠΎΡΠΎΡΠ΅Π½Π½ΠΎΠΉ ΠΌΠ°ΡΡΠΎΠΉ.Π£ Π»ΡΠ½ΡΠΉΠ½ΡΠΉ Ρ Π½Π΅Π»ΡΠ½ΡΠΉΠ½ΡΠΉ ΠΏΠΎΡΡΠ°Π½ΠΎΠ²ΠΊΠ°Ρ
ΡΠΎΠ·Π²'ΡΠ·Π°Π½ΠΎ Π·Π°Π΄Π°ΡΡ ΠΏΡΠΎ ΡΡΡΠΉΠΊΡΡΡΡ ΡΡΠ°ΡΡΠΎΠ½Π°ΡΠ½ΠΈΡ
ΡΡΡ
ΡΠ² ΠΎΠ΄Π½ΠΎΠ»Π°Π½ΠΊΠΎΠ²ΠΎΠ³ΠΎ ΠΌΠ°ΡΡΠ½ΠΈΠΊΠ° Π² Π³ΡΠ±ΡΠΈΠ΄Π½ΡΠΉ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΌΠ΅Ρ
Π°Π½ΡΡΠ½ΠΎΡ ΡΠΈΡΡΠ΅ΠΌΠΈ, ΡΠΊΠ° ΡΠΊΠ»Π°Π΄Π°ΡΡΡΡΡ Π· Π³ΠΎΡΠΈΠ·ΠΎΠ½ΡΠ°Π»ΡΠ½ΠΎ ΡΠΎΠ·ΠΌΡΡΠ΅Π½ΠΎΡ ΡΡΡΡΠ½ΠΈ, Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½ΠΎΡ ΠΊΠΎΠ»ΠΈΠ²Π½ΠΎΡ Π·ΠΎΡΠ΅ΡΠ΅Π΄ΠΆΠ΅Π½ΠΎΡ ΠΌΠ°ΡΠΎΡ.The problem of stability of the stationary motions of a single-mass pendulum in the hybrid model of one mechanical system is solved in the linear and nonlinear statements. The mechanical system consists of a string which is horizontally disposed and loaded by an oscillating localized mass
Detection and mapping of hydrothermally altered rocks in the vicinity of the comstock lode, Virginia Range, Nevada, using enhanced LANDSAT images
The author has identified the following significant results. LANDSAT images enhanced by the band-ratioing method can be used for reconnaissance alteration mapping in moderately heavily vegetated semiarid terrain as well as in sparsely vegetated to semiarid terrain where the technique was originally developed. Significant vegetation cover in a scene, however, requires the use of MSS ratios 4/5, 4/6, and 6/7 rather than 4/5, 5/6, and 6/7, and requires careful interpretation of the results. Supplemental information suitable to vegetation identification and cover estimates, such as standard LANDSAT false-color composites and low altitude aerial photographs of selected areas is desirable
Invariant sets for discontinuous parabolic area-preserving torus maps
We analyze a class of piecewise linear parabolic maps on the torus, namely
those obtained by considering a linear map with double eigenvalue one and
taking modulo one in each component. We show that within this two parameter
family of maps, the set of noninvertible maps is open and dense. For cases
where the entries in the matrix are rational we show that the maximal invariant
set has positive Lebesgue measure and we give bounds on the measure. For
several examples we find expressions for the measure of the invariant set but
we leave open the question as to whether there are parameters for which this
measure is zero.Comment: 19 pages in Latex (with epsfig,amssymb,graphics) with 5 figures in
eps; revised version: section 2 rewritten, new example and picture adde
Geologic applications of ERTS images on the Colorado Plateau, Arizona
Three areas in central and northern Arizona centered on the (1) Verde Valley, (2) Coconino Plateau, and (3) Shivwits Plateau were studied using ERTS photography. Useful applications results include: (1) upgrading of the existing state geologic map of the Verde Valley region; (2) detection of long NW trending lineaments in the basalt cap SE of Flagstaff which may be favorable locations for drilling for new water supplies; (3) tracing of the Bright Angel and Butte faults to twice their previously known length and correlating the extensions with modern seismic events, showing these faults to be present-day earthquake hazards; (4) discovering and successfully drilling perched sandstone aquifers in the Kaibab Limestone on the Coconino Plateau; and (5) determining the relationship between the Shivwits lavas and the formation of the lower Grand Canyon and showing that the lavas should be an excellent aquifer, as yet untapped
Preliminary geologic investigations in the Colorado Plateau using enhanced ERTS images
Bulk and computer enhanced frames of the Verde Valley region of Central Arizona, have been analyzed for structural information and rock unit identification. Most major rock units in areas of sparse ground cover are identifiable on enhanced false-color composites. Regional structural patterns are strikingly visible on the ERTS images. New features have been identified which will aid in the search for ground water near Flagstaff, Sedona and Stewart Ranch
Application of ERTS and EREP images to geologic investigations of the basin and range: Colorado plateau boundary in northwestern and north-central Arizona
The author has identified the following significant results. In the course of the ERTS investigation in the Cataract Creek Basin of the Coconino Plateau it was recognized that shallow perched ground water associated with the Kaibab Limestone could be discovered by means of drilling guided by geologic mapping aided by the use of ERTS imagery. At the Globe Ranch, the perched water table is only 5 meters beneath the surface at the site of the original, hand dug well. Recharge occurs from local runoff and from direct precipitation on the outcrop belt of the sandstone. This well provides water for the ranch at the rate of about 1,000 gallons a week. In order to explore the possibility of further developing this aquifer, unit 5 was mapped over an area of about 50 square miles in the vicinity of the hand-dug well, with negative results. A new location was then picked for drilling based on the occurrence of unit 5 in a favorable structural setting. This location was along a normal fault, and it was anticipated that water might be structurally trapped within the down-dropped block of the fault. Four shallow testholes were drilled and all encountered water. These four water-bearing holes are currently being monitored and will be tested to determine potential production of water from the local sandstone aquifer
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