23,401 research outputs found
Evaluation of low cost/high temperature insulation, July 1974 - June 1975
Six fiber products and six insulation blankets comprising silica, alumina, zirconia, mullite, and mixed ceramic systems were subjected to furnace exposures up to 500 hours at temperatures of 1000 to 1600 C and evaluated for chemical and dimensional stability and for changes in thermal conductivity. Alumina, zirconia, and mullite fibers were fabricated into reusable surface insulation (RSI) tile by water-felting and reimpregnation with ethyl silicate. Specimens were exposed to 25 thermal cycles at 1200 C and 1400 C and a pressure of 10 and 32 torr, respectively. Production costs for 930 sq m (10,000 sq ft) of blanket insulation and of alumina RSI tile were developed
Power Transitions in a Troubled Democracy
Written as our contribution to a festschrift for the noted Italian administrative law scholar Marco DâAlberti, this essay addresses transition between Presidents Trump and Biden, in the context of political power transitions in the United States more generally. Although the Trump-Biden transition was marked by extraordinary behaviors and events, we thought even the transitionâs mundane elements might prove interesting to those for whom transitions occur in a parliamentary context. There, succession can happen quickly once an electionâs results are known, and happens with the new political government immediately formed and in office. The layer of a new administrationâs political leadership directing its activities is generally quite thin, dependent on the training and discipline of the permanent civil service populating high as well as low elements of government to implement its policies. If, as is often the case, the incoming ministers have been parliamentarians with a particular interest in the matters for which they are now responsible as ministers â perhaps even as shadow ministers for the opposition â they may already know a good deal about and have relationships with the civil service staffs they will be inheriting. And the continuity of staff and tradition of service across different governments also benefits newcomers, easing the learning curve they face upon taking office. They do not need the transition teams that new Presidents use to educate themselves about the government they are about to lead.
Neither the President nor a new member of Congress, however, takes office immediately after national elections. Although the election may have considerably changed Congressâ political complexion, the pre-election Congress remains in office for two more months, and although the voters may have elected a Democrat to replace a Republican President, the Republican President and his political appointees in the executive branch â including all departmental and important agency heads â can remain in office at least seventeen days after the new Congress convenes. This transition time gives the outgoing President a window in which to further policies that the voters may just have rejected. âThere is something profoundly troubling,â Sanford Levinson of the University of Texas wrote in anticipation of the election of 1996, âin allowing repudiated presidents to continue to exercise the prerogatives of what is usually called âthe most powerful political office in the world.â
Power transition in the United States is further complicated by the thickness of the political layer within governmental departments and agencies; by the absence of any practical need for presidential candidates to commit themselves before election to the more important appointments they will make if elected; by the way the Constitutionâs explicit separation of service in Congress and the Executive branch impacts the likelihood that new appointees will be familiar with the operation of the body to which they are appointed; and by the necessity that the Presidentâs choices for the most important political positions in his administration be confirmed (approved for their office after a public hearing before the relevant committee) by the Senate then sitting. All of this can considerably slow, overall, the process of political change. Changing course has the speed and difficulty of navigating a large, heavy vessel, not a simple motorboat.
The transition from Trump to Biden, then, is both troubled and troubling. As work on this essay was concluding, Republican senators used the filibuster to block creation of a bipartisan commission to investigate and report on the January 6 assault on Congress by legislation Republican negotiators had accepted as balanced â and in the national transition of such inquiries in response to major national events. The legislative situation, given both the narrowness of Democrat control and the stated priorities of Republican leadership to put all their efforts into blocking the new administrationâs success â using party discipline to preclude bipartisanship â will not just stymie legislation. The tools of executive power are now in President Bidenâs hands, and these roadblocks may tempt him further down the paths his predecessors have taken, asserting increasing control over executive governmentâs functioning, acting on his own where cooperation cannot be had. To repair the political damage President Trump inflicted on the government bureaucracy may prove impossible without President Biden appearing himself still further to thicken the political layers atop the civil service. Admiring his motivations, and troubled by the administration he succeeded, the difficulty is seeing a clear path back to a government constrained by the norms that had long kept our democracy safe
Sensitive Radio Survey of Obscured Quasar Candidates
We study the radio properties of moderately obscured quasars over a range of
redshifts to understand the role of radio activity in accretion using the
Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists
of optically-selected obscured quasar candidates, all of which are radio-quiet,
with typical radio luminosities of [1.4 GHz] < erg
s. Only a single source is individually detected in our deep (rms~10
Jy) exposures. This population would not be identified by radio-based
selection methods used for distinguishing dusty star-forming galaxies and
obscured active nuclei. In our pilot A-array study of z~0.5 radio-quiet
quasars, we spatially resolve four of five objects on scales ~ 5 kpc and find
they have steep spectral indices. Therefore, radio emission in these sources
could be due to jet-driven or radiatively driven bubbles interacting with
interstellar material on the scale of the host galaxy. Finally, we also study
the population of ~ 200 faint (~40 Jy - 40 mJy) radio sources observed
over ~ 120 arcmin of our data. 60% of these detections are matched in the
SDSS and/or WISE and are, in roughly equal shares, active nuclei at a broad
range of redshifts, passive galaxies with no other signs of nuclear activity
and IR-bright but optically faint sources. Spectroscopically or photometrically
confirmed star-forming galaxies constitute only a small minority of the
matches. Such sensitive radio surveys allow us to address important questions
of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.Comment: 18 pages, submitted to MNRA
Probing the Ionization State of the Universe at z>6
We present high signal-to-noise ratio Keck ESI spectra of the two quasars
known to have Gunn-Peterson absorption troughs, SDSS J1030+0524 (z=6.28) and
SDSS J1148+5251 (z=6.37). The Ly alpha and Ly beta troughs for SDSS J1030+0524
are very black and show no evidence for any emission over a redshift interval
of ~0.2 starting at z=6. On the other hand, SDSS J1148+5251 shows a number of
emission peaks in the Ly beta Gunn-Peterson trough along with a single weak
peak in the Ly alpha trough. The Ly alpha emission has corresponding Ly beta
emission, suggesting that it is indeed a region of lower optical depth in the
intergalactic medium at z=6.08.
The stronger Ly beta peaks in the spectrum of SDSS J1148+5251 could
conceivably also be the result of "leaks" in the IGM, but we suggest that they
are instead Ly alpha emission from an intervening galaxy at z=4.9. This
hypothesis gains credence from a strong complex of C IV absorption at the same
redshift and from the detection of continuum emission in the Ly alpha trough at
the expected brightness. If this proposal is correct, the quasar light has
probably been magnified through gravitational lensing by the intervening
galaxy. The Stromgren sphere observed in the absorption spectrum of SDSS
J1148+5251 is significantly smaller than expected based on its brightness,
which is consistent with the hypothesis that the quasar is lensed.
If our argument for lensing is correct, the optical depths derived from the
troughs of SDSS J1148+5251 are only lower limits (albeit still quite strong,
with tau(LyA)>16 inferred from the Ly beta trough.) The Ly beta absorption
trough of SDSS J1030+0524 gives the single best measurement of the IGM
transmission at z>6, with an inferred optical depth tau(LyA)>22.Comment: To appear in July 2003 AJ, 34 pages, 11 figures; minor changes/typos
fixe
Representation of Quantum Mechanical Resonances in the Lax-Phillips Hilbert Space
We discuss the quantum Lax-Phillips theory of scattering and unstable
systems. In this framework, the decay of an unstable system is described by a
semigroup. The spectrum of the generator of the semigroup corresponds to the
singularities of the Lax-Phillips -matrix. In the case of discrete (complex)
spectrum of the generator of the semigroup, associated with resonances, the
decay law is exactly exponential. The states corresponding to these resonances
(eigenfunctions of the generator of the semigroup) lie in the Lax-Phillips
Hilbert space, and therefore all physical properties of the resonant states can
be computed.
We show that the Lax-Phillips -matrix is unitarily related to the
-matrix of standard scattering theory by a unitary transformation
parametrized by the spectral variable of the Lax-Phillips theory.
Analytic continuation in has some of the properties of a method
developed some time ago for application to dilation analytic potentials.
We work out an illustrative example using a Lee-Friedrichs model for the
underlying dynamical system.Comment: Plain TeX, 26 pages. Minor revision
Microwave and hard X-ray observations of a solar flare with a time resolution of better than 100 MS
Simultaneous microwave and X-ray observations are presented for a solar flare detected on 1980 May 8 starting at 1937 UT. The X-ray observations were made with the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission and covered the energy range from 28-490 keV with a time resolution of 10 ms. The microwave observations were made with the 5 and 45 foot antennas at the Itapetinga Radio Observatory at frequencies of 7 and 22 GHz, with time resolutions of 100 ms and 1 ms respectively. Detailed correlation analysis of the different time profiles of the event show that the major impulsive in the X-ray flux preceded the corresponding microwave peaks at 22 GHz by about 240ms. For this particular burst the 22 GHz peaks preceded the 7 GHz by about 1.5s. Observed delays of the microwave peaks are too large for a simple electron beam model but they can be reconciled with the speeds of shock waves in a thermal model
An exploration into the client at the heart of therapy : a qualitative perspective
Over 50 years ago Eysenck challenged the existing base of research into psychotherapy. Since that time, a large number of investigations have been conducted to verify the efficacy of therapy. Recently however, an increasing number of studies have cast new doubts on this research base. Instead of therapy being a function of the therapist, it is now becoming ever more apparent that the client plays a prime role in the therapeutic process. The qualitative studies presented in this paper provide some examples of research that demonstrates that clients are actively involved in their therapy, even making counselling work despite their counsellor. These studies suggest that clients may not experience therapy as beneficially as traditional outcome studies indicate. This raises a new challenge to researchers to more fully explore the client's experience of therapy, a challenge to which qualitative methods of inquiry would appear well suited
Unique Continuation for Schr\"odinger Evolutions, with applications to profiles of concentration and traveling waves
We prove unique continuation properties for solutions of the evolution
Schr\"odinger equation with time dependent potentials. As an application of our
method we also obtain results concerning the possible concentration profiles of
blow up solutions and the possible profiles of the traveling waves solutions of
semi-linear Schr\"odinger equations.Comment: 23 page
Distributed-Pair Programming can work well and is not just Distributed Pair-Programming
Background: Distributed Pair Programming can be performed via screensharing
or via a distributed IDE. The latter offers the freedom of concurrent editing
(which may be helpful or damaging) and has even more awareness deficits than
screen sharing. Objective: Characterize how competent distributed pair
programmers may handle this additional freedom and these additional awareness
deficits and characterize the impacts on the pair programming process. Method:
A revelatory case study, based on direct observation of a single, highly
competent distributed pair of industrial software developers during a 3-day
collaboration. We use recordings of these sessions and conceptualize the
phenomena seen. Results: 1. Skilled pairs may bridge the awareness deficits
without visible obstruction of the overall process. 2. Skilled pairs may use
the additional editing freedom in a useful limited fashion, resulting in
potentially better fluency of the process than local pair programming.
Conclusion: When applied skillfully in an appropriate context, distributed-pair
programming can (not will!) work at least as well as local pair programming
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