13,910 research outputs found
Automatic closed circuit television arc guidance control Patent
Automatic closed circuit television arc guidance control for welding joint
Investigation of slosh anomaly in Apollo lunar module propellant gage
Analysis of propellant sloshing in lunar module during Apollo 14 flight and resultant erroneous indication of low level of propellan
Excimer lasers
A theoretical and experimental investigation into the possibility of achieving CW discharge pumped excimer laser oscillation is reported. Detailed theoretical modeling of capillary discharge pumping of the XeF and KXe and K2 excimer systems was carried out which predicted the required discharge parameters for reaching laser threshold on these systems. Capillary discharge pumping of the XeF excimer system was investigated experimentally. The experiments revealed a lower excimer level population density than predicted theoretically by about an order of magnitude. The experiments also revealed a fluorine consumption problem in the discharge in agreement with theory
Excimer lasers
The results of a two-year investigation into the possibility of developing continuous wave excimer lasers are reported. The program included the evaluation and selection of candidate molecular systems and discharge pumping techniques. The K Ar/K2 excimer dimer molecules and the xenon fluoride excimer molecule were selected for study; each used a transverse and capillary discharges pumping technique. Experimental and theoretical studies of each of the two discharge techniques applied to each of the two molecular systems are reported. Discharge stability and fluorine consumption were found to be the principle impediments to extending the XeF excimer laser into the continuous wave regime. Potassium vapor handling problems were the principal difficulty in achieving laser action on the K Ar/K2 system. Of the four molecular systems and pumping techniques explored, the capillary discharge pumped K Ar/K2 system appears to be the most likely candidate for demonstrating continuous wave excimer laser action primarily because of its predicted lower pumping threshold and a demonstrated discharge stability advantage
The Final Fate of Binary Neutron Stars: What Happens After the Merger?
The merger of two neutron stars usually produces a remnant with a mass
significantly above the single (nonrotating) neutron star maximum mass. In some
cases, the remnant will be stabilized against collapse by rapid, differential
rotation. MHD-driven angular momentum transport eventually leads to the
collapse of the remnant's core, resulting in a black hole surrounded by a
massive accretion torus. Here we present simulations of this process. The
plausibility of generating short duration gamma ray bursts through this
scenario is discussed.Comment: 3 pages. To appear in the Proceedings of the Eleventh Marcel
Grossmann Meeting, Berlin, Germany, 23-29 July 2006, World Scientific,
Singapore (2007
Unexpected Side Effects: A Cautionary Note on Challenges of Persistent Self-Transcendence
Self-transcendence is an ambiguous construct without consensual meaning, yet many claim that it relates to, or even causes, beneficial outcomes. Few discuss its potential deleterious side effects, choosing to focus primarily on positive effects. However, anything with sufficient potency to heal may have unintended side effects, especially when it leads beyond a transitory state to becoming an enduring trait, such as when self-transcendence (ST) becomes persistent self-transcendence (PST). With PST, evidence is overviewed here, along with two illustrative case reports, that people can suffer emotional difficulties, motivation changes, loss of self-reflexivity, anhedonia, dissociation, depersonalization, memory problems, and other psychological concerns. This is discussed in terms of the disruption of the sense of self, which ordinarily serves as an integrative center for the person that conveys a sense of agency. Possible neurobiological and sociocultural effects of PST are also discussed, with a focus on its role on narrative memory as the construction of self-concept. Evidence has also been accumulating on problematic side effects of meditation and mindfulness, techniques commonly presented as paths to PST. Given that PST is often presented as a pinnacle of human development and spiritual attainment, seekers of PST, psychologists, and other mental health professionals are urged to become informed about its possible side effects, and view this phenomenon in a more balanced way
Metallicity of Red Giants in the Galactic Bulge from Near-Infrared Spectroscopy
We present K-band spectra of more than 110 M giants in Galactic bulge fields
interior to -4 degrees and as close as 0.2 degrees of the Galactic Center. From
the equivalent widths of three features in these spectra, EW(Na),EW(Ca), and
EW(CO) we calculate [Fe/H] for the stars with a calibration derived from
globular clusters Stephens et al (2000). The mean [Fe/H] for each field is in
good agreement with the results from Frogel et al. (1999) based on the slope of
the giant branch method. We find no evidence for a metallicity gradient along
the minor or major axes of the inner bulge (R < 0.6 kpc). A metallicity
gradient along the minor axis, found earlier, arises when fields located at
larger galactic radius are included. However, these more distant fields are
located outside of the infrared bulge defined by the COBE/DIRBE observations.
We compute the [Fe/H] distribution for the inner bulge and find a mean value of
-0.21 dex with a full width dispersion of 0.30 dex, close to the values found
for Baade's Window (BW) by Sadler et al. (1996) and to a theoretical prediction
for a bulge formed by dissipative collapse Molla et al (2000).Comment: 32 pages, 10 figures, AJ submitte
- …