5,957 research outputs found
Hybrid holographic system using reflected and transmitted object beams simultaneously Patent
Hybrid holographic system using reference, transmitted, and reflected beams simultaneousl
Hybrid holographic system
Improved holographic system has high degree of resolution and capability of providing a hologram of a moving object without requiring that the system have a high mechanical stability
Experimental aerodynamic characteristics of vehicles traveling in tubes
A simplified theoretical model for a vehicle traveling through an unvented tube under equilibrium incompressible conditions was used to guide the test program, reduce the data, and determine the self-consistency of the results. The results were then used to establish values for the arbitrary coefficients in the theoretical model. Substantial progress was made in understanding the aerodynamic characteristics of vehicles traveling in tubes as exemplified by the good agreement of the theoretical model predictions with the experimental data throughout the Reynolds number range (three orders of magnitude, up to that for an actual full-scale system) and the many geometric variables tested
The Nainital-Cape Survey -- II:Report for pulsation in five chemically peculiar A-type stars and presentation of 140 null results
To search photometric variability in chemically peculiar A type stars in the
northern hemisphere. High-speed photometric observations of Ap and Am star
candidates have been carried out from ARIES (Manora Peak, Nainital) using a
three-channel fast photometer attached to the ARIES 104-cm Sampurnanand
telescope. This paper presents three new variables: HD 113878, HD 118660 and HD
207561. During the time span of the survey (1999 December to 2004 January)
pulsations of the Sct type were also found for the two evolved Am
stars HD 102480 and HD 98851, as reported in Joshi et al. (2002, 2003).
Additionally, we present 140 null results of the survey for this time span. The
star HD 113878 pulsates with a period of 2.31 hr, which is typical of
Sct stars. HD 118660 exhibits multi-periodic variability with a prominent
period of nearly 1 hr. These periods need to be investigated and make HD 118660
a particularly interesting target for further observations. For HD 207561, a
star classified as Am, a probable pulsation with a period of 6 min was found in
the light curves obtained on two consecutive nights. Both HD 102480 and HD
98851 exhibit unusual alternating high and low amplitude maxima, with a period
ratio of 2:1. The analysis of the null results confirms the photometric quality
of the NainitalComment: 14 pages, 13 figures, Accepted for publication in A&
MOST observations of the roAp stars HD 9289, HD 99563, and HD 134214
We report on the analysis of high-precision space-based photometry of the
roAp (rapidly oscillating Ap) stars HD 9289, HD 99563, and HD134214. All three
stars were observed by the MOST satellite for more than 25 days, allowing
unprecedented views of their pulsation. We find previously unknown candidate
frequencies in all three stars. We establish the rotation period of HD 9289
(8.5 d) for the first time and show that the star is pulsating in two modes
that show different mode geometries. We present a detailed analysis of HD
99563's mode multiplet and find a new candidate frequency which appears
independent of the previously known mode. Finally, we report on 11 detected
pulsation frequencies in HD 134214, 9 of which were never before detected in
photometry, and 3 of which are completely new detections. Thanks to the
unprecedentedly small frequency uncertainties, the p-mode spectrum of HD 134214
can be seen to have a well-defined large frequency spacing similar to the
well-studied roAp star HD 24712 (HR 1217).Comment: 11 pages, 12 figures, accepted for publication in A&
Investigating the Effects of Adult Insecure Attachment on Interpersonal Attraction
The present study examined the relationship between variables of insecure attachment and feelings of initial attraction between young adults. Previous research has consistently supported the positive link between anxious attachment and hyperactivation of the attachment system in adults, resulting in preoccupied proximity seeking evaluations and behaviors. As such, emerging findings suggest that anxious attachment contributes to elevated levels of interpersonal attraction upon initial meetings with others, particularly those who may serve as future romantic partners. Despite a growing body of literature, little is known or understood about the impact of avoidant attachment in shaping early views of others, or how attachment avoidance may impact the relationship between anxiety and attraction. Utilizing an analogue, speed-dating context, this study explored the relationships between attachment anxiety, attachment avoidance, and interpersonal attraction occurring between young adult (i.e., ages 18-22) male-female dyads who were previously unacquainted. Participants were asked to converse and share stories for 10 minutes with each other, and then to independently complete measures of adult attachment and their feelings of attraction towards their experimental partner. Contradictory to what was expected, attachment anxiety did not predict elevated interpersonal attraction (F [1, 94] = .02, p = .88), nor did avoidance significantly moderate this relationship (F [1, 89] = 1.07, p = .30). Despite a lack of support for principal hypotheses, alternative findings suggested a positive relationship between attachment anxiety and attachment avoidance (r = .51, p \u3c .01), as well as a negative relationship between relationship status and attachment anxiety (r = -.50, p \u3c .01) and avoidance (r = -.52, p \u3c .01). These results offer emerging insight to clinicians working with insecurely attached patients aiming to facilitate intimate relationship building
A Tight Upper Limit on Oscillations in the Ap star Epsilon Ursae Majoris from WIRE Photometry
Observations of Epsilon UMa obtained with the star tracker on the Wide Field
Infrared Explorer (WIRE) satellite during a month in mid-2000 are analyzed.
This is one of the most precise photometry of an Ap star. The amplitude
spectrum is used to set an upper limit of 75 parts per million for the
amplitude of stellar pulsations in this star unless it accidentally oscillates
with a single mode at the satellite orbit, its harmonics or their one day
aliases. This is the tightest limit put on the amplitude of oscillations in an
Ap star. As the rotation period of Epsilon UMa is relatively short (5.1 d), it
cannot be argued that the observations were made at a wrong rotational phase.
Our results thus support the idea that some Ap stars do not pulsate at all.Comment: 4 pages, 4 figures, 2 style files, accepted for publication in ApJ
Sky camera geometric calibration using solar observations
A camera model and associated automated calibration procedure for stationary
daytime sky imaging cameras is presented. The specific modeling and
calibration needs are motivated by remotely deployed cameras used to forecast
solar power production where cameras point skyward and use 180°
fisheye lenses. Sun position in the sky and on the image plane provides
a simple and automated approach to calibration; special equipment or
calibration patterns are not required. Sun position in the sky is modeled
using a solar position algorithm (requiring latitude, longitude, altitude and
time as inputs). Sun position on the image plane is detected using a simple
image processing algorithm. The performance evaluation focuses on the
calibration of a camera employing a fisheye lens with an equisolid angle
projection, but the camera model is general enough to treat most fixed focal
length, central, dioptric camera systems with a photo objective lens.
Calibration errors scale with the noise level of the sun position measurement
in the image plane, but the calibration is robust across a large range of
noise in the sun position. Calibration performance on clear days ranged from
0.94 to 1.24 pixels root mean square error
Determining the profitability of timber stand improvement investments
"You can increase the financial return from a tract (stand) of Missouri forest land by improving tree quality and woodland composition. Timber Stand Improvement (TSI) includes a broad range of practices: site preparation, thinning, release, pruning, and vine and weed removal."--First page.William B. Kurtz and Carol B. Trokey (School of Forestry, Fisheries and Wildlife, College of Agriculture)New 8/84/8
Triggered massive-star formation on the borders of Galactic HII regions. III. Star formation at the periphery of Sh2-219
Context. Massive-star formation triggered by the expansion of HII regions.
Aims. To understand if sequential star formation is taking place at the
periphery of the HII region Sh2-219. Methods. We present 12CO(2-1) line
observations of this region, obtained at the IRAM 30-m telescope (Pico Veleta,
Spain). Results. In the optical, Sh2-219 is spherically symmetric around its
exciting star; furthermore it is surrounded along three quarters of its
periphery by a ring of atomic hydrogen. This spherical symmetry breaks down at
infrared and millimetre wavelengths. A molecular cloud of about 2000\msol lies
at the southwestern border of Sh2-219, in the HI gap. Two molecular
condensations, elongated along the ionization front, probably result from the
interaction between the expanding HII region and the molecular cloud. In this
region of interaction there lies a cluster containing many highly reddened
stars, as well as a massive star exciting an ultracompact HII region. More
surprisingly, the brightest parts of the molecular cloud form a `chimney',
perpendicular to the ionization front. This chimney is closed at its south-west
extremity by H-alpha walls, thus forming a cavity. The whole structure is 7.5
pc long. A luminous H-alpha emission-line star, lying at one end of the chimney
near the ionization front, may be responsible for this structure. Confrontation
of the observations with models of HII region evolution shows that Sh2-219 is
probably 10^5 yr old. The age and origin of the near-IR cluster observed on the
border of Sh2-219 remain unknown.Comment: 11 pages, 10 figures. To be published in A&
- …