6,402 research outputs found
Design and manufacture of direct current torquer amplifiers Final summary report
Design and manufacture of direct current torquer amplifier with pulse width modulation circui
Data analysis of continuous gravitational wave: Fourier transform-I
We present the Fourier Transform of a continuous gravitational wave. We have
analysed the data set for one day observation time and our analysis is
applicable for arbitrary location of detector and source. We have taken into
account the effects arising due to rotational as well as orbital motions of the
earth.Comment: Accepted in MNRAS, 22 pages, 9 figure
Time to Reconsider Nullum Tempus Occurrit Regi - The Applicability of Statutes of Limitations Against the State of Maine in Civil Actions
Many states, including the State of Maine, take the position that they have, essentially, an infinite time within which to bring a civil action. The basis for the State\u27s claim of immunity from statutes of limitations is the old English common law doctrine, “nullum tempus occurrit regi”-- literally, no time runs against the King--which purports to exempt the State from statutes of limitations of general applicability unless statutes expressly provide otherwise. There has not been a Maine Supreme Judicial Court (Law Court) opinion mentioning the nullum tempusdoctrine since 1955, but the doctrine continues to be actively asserted by the State of Maine in civil actions filed in Superior Court. At least six Superior Court decisions since 1990 reference the nullum tempus doctrine. It is high time to consider whether the doctrine should remain good law in Maine. The Law Court abolished common law sovereign immunity from tort claims in 1976; over the last twelve years the high courts of the states of Colorado, New Jersey, and South Carolina have abrogated the nullum tempus doctrine, and the doctrine is ripe for policy reevaluation in light of the split in authority and changing concepts of justice. Given the not infrequent assertion of the doctrine by the State of Maine in civil actions, it is only a matter of time before the nullum tempus doctrine again comes before the Law Court. This Article analyzes current Maine law on the applicability of statutes of limitations to the State, specifically whether the nullum tempus doctrine should remain good law in Maine, and suggests that the doctrine is ripe for abrogation
Geophysical parameters from the analysis of laser ranging to Starlette
The results of geodynamic research from the analysis of satellite laser ranging data to Starlette are summarized. The time period of the investigation was from 15 Mar. 1986 to 31 Dec. 1991. As a result of the Starlette research, a comprehensive 16-year Starlette data set spanning the time period from 17 Mar. 1975 through 31 Dec. 1990, was produced. This data set represents the longest geophysical time series from any geodetic satellite and is invaluable for research in long-term geodynamics. A low degree and order ocean tide solution determined from Starlette has good overall agreement with other satellite and oceanographic tide solutions. The observed lunar deceleration is -24.7 +/- 0.6 arcsecond/century(exp 2), which agrees well with other studies. The estimated value of J2 is (-2.5 +/- 0.3) x 10(exp -11) yr(exp -1), assuming there are no variations in higher degree zonals and that the 18.6-year tide is fixed at an equilibrium value. The yearly fluctuations in the values for S(sub a) and S(sub sa) tides determined by the 16-year Starlette data are found to be associated with changes in the Earth's second degree zonal harmonic caused primarily by meteorological excitation. The mean values for the amplitude of S(sub a) and S(sub sa) variations in J2 are 32.3 x 10(exp -11) and 19.5 x 10(exp -11), respectively; while the rms about the mean values are 4.1 x 10(exp -11) and 6.3(10)(exp -11), respectively. The annual delta(J2) is in good agreement with the value obtained from the combined effects of air mass redistribution without the oceanic inverted-barometer effects and hydrological change. The annual delta(J3) values have much larger disagreements. Approximately 90 percent of the observed annual variation from Starlette is attributed to the meteorological mass redistribution occurring near the Earth's surface
Altimeter measurements for the determination of the Earth's gravity field
The ability of satellite-borne radar altimeter data to measure the global ocean surface with high precision and dense spatial coverage provides a unique tool for the mapping of the Earth's gravity field and its geoid. The altimeter crossover measurements, created by differencing direct altimeter measurements at the subsatellite points where the orbit ground tracks intersect, have the distinct advantage of eliminating geoid error and other nontemporal or long period oceanographic features. In the 1990's, the joint U.S./French TOPEX/POSEIDON mission and the European Space Agency's ERS-1 mission will carry radar altimeter instruments capable of global ocean mapping with high precision. This investigation aims at the development and application of dynamically consistent direct altimeter and altimeter crossover measurement models to the simultaneous mapping of the Earth's gravity field and its geoid, the ocean tides and the quasi-stationary component of the dynamic sea surface topography. Altimeter data collected by SEASAT, GEOS-3, and GEOSAT are used for the investigation
Altimeter measurements for the determination of the Earth's gravity field
Progress in the following areas is described: refining altimeter and altimeter crossover measurement models for precise orbit determination and for the solution of the earth's gravity field; performing experiments using altimeter data for the improvement of precise satellite ephemerides; and analyzing an optimal relative data weighting algorithm to combine various data types in the solution of the gravity field
Simple models for the shuttle remote manipulator system
The investigation is aimed at establishing a series of simple models which can be used to study the forces and moments which occur due to the reaction control system (RCS) jet plume firings during a deployment or retrieval of an IUS type payload. The models considered in this investigation are primarily planar in nature. In this study primary attention is given to the roles the payload play in determining the overall moments on the remote manipulator system arm
Implementation of barycentric resampling for continuous wave searches in gravitational wave data
We describe an efficient implementation of a coherent statistic for
continuous gravitational wave searches from neutron stars. The algorithm works
by transforming the data taken by a gravitational wave detector from a moving
Earth bound frame to one that sits at the Solar System barycenter. Many
practical difficulties arise in the implementation of this algorithm, some of
which have not been discussed previously. These difficulties include
constraints of small computer memory, discreteness of the data, losses due to
interpolation and gaps in real data. This implementation is considerably more
efficient than previous implementations of these kinds of searches on Laser
Interferometer Gravitational Wave (LIGO) detector data.Comment: 10 pages, 3 figure
Vacuum entanglement enhancement by a weak gravitational field
Separate regions in space are generally entangled, even in the vacuum state.
It is known that this entanglement can be swapped to separated Unruh-DeWitt
detectors, i.e., that the vacuum can serve as a source of entanglement. Here,
we demonstrate that, in the presence of curvature, the amount of entanglement
that Unruh-DeWitt detectors can extract from the vacuum can be increased.Comment: 6 pages, 1 figur
Coherent Line Removal: Filtering out harmonically related line interference from experimental data, with application to gravitational wave detectors
We describe a new technique for removing troublesome interference from
external coherent signals present in the gravitational wave spectrum. The
method works when the interference is present in many harmonics, as long as
they remain coherent with one another. The method can remove interference even
when the frequency changes. We apply the method to the data produced by the
Glasgow laser interferometer in 1996 and the entire series of wide lines
corresponding to the electricity supply frequency and its harmonics are
removed, leaving the spectrum clean enough to detect possible signals
previously masked by them. We also study the effects of the line removal on the
statistics of the noise in the time domain. We find that this technique seems
to reduce the level of non-Gaussian noise present in the interferometer and
therefore, it can raise the sensitivity and duty cycle of the detectors.Comment: 14 pages, 8 figures, Revtex, psfig. To appear in Phys. Rev.
- …