169 research outputs found
Relaxing and Communication-Promoting Effects of Wooden Tableware at Workplace Social Gathering
Human beings are thought to have evolved in close contact with wood and touching wood is known to have relaxing effects. In 10 health subjects participating workplace social gathering, the effects of the use of wooden tableware on autonomic functions and communication were examined in comparison to the use of porcelain-metal tableware with a crossover study design. Analysis of pulse rate variability revealed that, compared to porcelain-metal tableware, wooden tableware lowered the amplitude of low-frequency (LF, 0.04-0.15 Hz) component without affecting the amplitude of high-frequency (HF, 0.15-0.45 Hz) component, resulting lower LF-to-HF ratio. Communication measured by the total number of utterances did not differ with the type of tableware. Subjective evaluation by a post questionnaire also showed consistent results, indicating better impression, warmth, relaxation, remission, nostalgic feeling for wooden tableware than porcelain-metal tableware. The use of wooden tableware may reduce sympathetic tone at the workplace social gathering compared to porcelain-metal tableware
The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS imager with "Co-axis double TMA"
IRIS (InfraRed Imaging Spectrograph) is one of the first-generation
instruments for the Thirty Meter Telescope (TMT). IRIS is composed of a
combination of near-infrared (0.84--2.4 m) diffraction limited imager and
integral field spectrograph. To achieve near-diffraction limited resolutions in
the near-infrared wavelength region, IRIS uses the advanced adaptive optics
system NFIRAOS (Narrow Field Infrared Adaptive Optics System) and integrated
on-instrument wavefront sensors (OIWFS). However, IRIS itself has challenging
specifications. First, the overall system wavefront error should be less than
40 nm in Y, z, J, and H-band and 42 nm in K-band over a 34.0 34.0
arcsecond field of view. Second, the throughput of the imager components should
be more than 42 percent. To achieve the extremely low wavefront error and high
throughput, all reflective design has been newly proposed. We have adopted a
new design policy called "Co-Axis double-TMA", which cancels the asymmetric
aberrations generated by "collimator/TMA" and "camera/TMA" efficiently. The
latest imager design meets all specifications, and, in particular, the
wavefront error is less than 17.3 nm and throughput is more than 50.8 percent.
However, to meet the specification of wavefront error and throughput as built
performance, the IRIS imager requires both mirrors with low surface
irregularity after high-reflection coating in cryogenic and high-level Assembly
Integration and Verification (AIV). To deal with these technical challenges, we
have done the tolerance analysis and found that total pass rate is almost 99
percent in the case of gauss distribution and more than 90 percent in the case
of parabolic distribution using four compensators. We also have made an AIV
plan and feasibility check of the optical elements. In this paper, we will
present the details of this optical system.Comment: 18 pages, 14 figures, Proceeding 9908-386 of the SPIE Astronomical
Telescopes + Instrumentation 201
The Infrared Imaging Spectrograph (IRIS) for TMT: the ADC optical design
We present the current optical design for the IRIS Atmospheric Dispersion Corrector (ADC). The ADC is designed for residual dispersions less than ~1 mas across a given passband at elevations of 25 degrees. Since the last report, the area of the IRIS Imager has increased by a factor of four, and the pupil size has increased from 75 to 90mm, both of which contribute to challenges with the design. Several considerations have led to the current design: residual dispersion, amount of introduced distortion, glass transmission, glass availability, and pupil displacement. In particular, it was found that there are significant distortions that appear (two different components) that can lead to image blur over long exposures. Also, pupil displacement increases the wave front error at the imager focus. We discuss these considerations, discuss the compromises, and present the final design choice and expected performance
The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric precision and ghost analysis
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the
Thirty Meter Telescope (TMT) that will be used to sample the corrected adaptive
optics field by NFIRAOS with a near-infrared (0.8 - 2.4 m) imaging camera
and Integral Field Spectrograph (IFS). In order to understand the science case
specifications of the IRIS instrument, we use the IRIS data simulator to
characterize photometric precision and accuracy of the IRIS imager. We present
the results of investigation into the effects of potential ghosting in the IRIS
optical design. Each source in the IRIS imager field of view results in ghost
images on the detector from IRIS's wedge filters, entrance window, and
Atmospheric Dispersion Corrector (ADC) prism. We incorporated each of these
ghosts into the IRIS simulator by simulating an appropriate magnitude point
source at a specified pixel distance, and for the case of the extended ghosts
redistributing flux evenly over the area specified by IRIS's optical design. We
simulate the ghosting impact on the photometric capabilities, and found that
ghosts generally contribute negligible effects on the flux counts for point
sources except for extreme cases where ghosts coalign with a star of
m2 fainter than the ghost source. Lastly, we explore the photometric
precision and accuracy for single sources and crowded field photometry on the
IRIS imager.Comment: SPIE 2018, 14 pages, 14 figures, 4 tables, Proceedings of SPIE
10702-373, Ground-based and Airborne Instrumentation for Astronomy VII,
10702A7 (16 July 2018
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