130 research outputs found
Comparison Between Shipping Container Homes and Regular Stick-built Homes in California
The Research that was conducted was to examine the differences and similarities between shipping container construction and stick-built construction within residential homes in California. Shipping Container construction has grown in popularity and has continued to make its way into many different construction industries. I wanted to find the reasoning behind why this has continued to grow and if it could be a future way to construct Californian homes. This information could change how future homebuilders construct homes in California. This information could also provide a home that has a different cost, schedule, and features that could benefit the owner. After conducting my research I have found that shipping container homes do not have the potential at this point in time to replace stick built homes in California. Shipping container homes provide a simple design, affordability, a short construction schedule, and the ability to be relocated easily. While these benefits apply to smaller simple homes and ADUs when constructing mid-size to large custom homes the affordability, schedule, and flexibility of design are diminished when constructing with shipping containers. Shipping container construction has a niche for the future of construction although, it will not overcome stick-built construction in typical Californian home building
Magnetospheric Accretion in Close Pre-Main-Sequence Binaries
The transfer of matter between a circumbinary disk and a young binary system remains poorly understood, obscuring the interpretation of accretion indicators. To explore the behavior of these indicators in multiple systems, we have performed the first systematic time-domain study of young binaries in the ultraviolet. We obtained far- and near-ultraviolet HST/COS spectra of the young spectroscopic binaries DQ Tau and UZ Tau E. Here we focus on the continuum from 2800 to 3200 Å and on the C iv doublet (λλ1548.19, 1550.77 Å) as accretion diagnostics. Each system was observed over three or four consecutive binary orbits, at phases ~0, 0.2, 0.5, and 0.7. Those observations are complemented by ground-based U-band measurements. Contrary to model predictions, we do not detect any clear correlation between accretion luminosity and phase. Further, we do not detect any correlation between C iv flux and phase. For both stars the appearance of the C iv line is similar to that of single Classical T Tauri Stars (CTTSs), despite the lack of stable long-lived circumstellar disks. However, unlike the case in single CTTSs, the narrow and broad components of the C iv lines are uncorrelated, and we argue that the narrow component is powered by processes other than accretion, such as flares in the stellar magnetospheres and/or enhanced activity in the upper atmosphere. We find that both stars contribute equally to the narrow component C iv flux in DQ Tau, but the primary dominates the narrow component C iv emission in UZ Tau E. The C iv broad component flux is correlated with other accretion indicators, suggesting an accretion origin. However, the line is blueshifted, which is inconsistent with its origin in an infall flow close to the star. It is possible that the complicated geometry of the region, as well as turbulence in the shock region, are responsible for the blueshifted line profiles
X-raying the Beating Heart of a Newborn Star: Rotational Modulation of High-energy Radiation from V1647 Ori
We report a periodicity of ~1 day in the highly elevated X-ray emission from
the protostar V1647 Ori during its two recent multiple-year outbursts of mass
accretion. This periodicity is indicative of protostellar rotation at
near-breakup speed. Modeling of the phased X-ray light curve indicates the
high-temperature (~50 MK), X-ray-emitting plasma, which is most likely heated
by accretion-induced magnetic reconnection, resides in dense (>~5e10 cm-3),
pancake-shaped magnetic footprints where the accretion stream feeds the newborn
star. The sustained X-ray periodicity of V1647 Ori demonstrates that such
protostellar magnetospheric accretion configurations can be stable over
timescales of years.Comment: 26 pages, 10 figure
Heuristics for Broader Assessment of Effectiveness and Usability in Technology-Mediated Technical Communication
Purpose: To offer additional tools for the assessment of effectiveness and usability in technology-mediated communication based in established heuristics.
Method: An interdisciplinary group of researchers at Rensselaer Polytechnic Institute selected five disparate examples of technology-mediated communication, formally evaluated each using contemporary heuristics, and then engaged in an iterative design process to arrive at an expanded toolkit for in depth analyses.
Results: A set of heuristics and operationalized metrics for the deeper analysis of a broader scope of contemporary technology-mediated communication.
Conclusions: The continual evolution of communication, including the emergence of new, interactive media, provides a challenging opportunity to identify effective approaches and techniques. There are benefits to a renewed focus on relationships between people and between people and information, and we offer additional criteria and metrics to supplement established means of heuristic analysis
HATNet Field G205: Follow-Up Observations of 28 Transiting-Planet candidates and Confirmation of the Planet HAT-P-8b
We report the identification of 32 transiting-planet candidates in HATNet
field G205. We describe the procedures that we have used to follow up these
candidates with spectroscopic and photometric observations, and we present a
status report on our interpretation of the 28 candidates for which we have
follow-up observations. Eight are eclipsing binaries with orbital solutions
whose periods are consistent with their photometric ephemerides; two of these
spectroscopic orbits are singled-lined and six are double-lined. For one of the
candidates, a nearby but fainter eclipsing binary proved to be the source for
the HATNet light curve, due to blending in the HATNet images. Four of the
candidates were found to be rotating more rapidly than vsini = 50 km/s and were
not pursued further. Thirteen of the candidates showed no significant velocity
variation at the level of 0.5 to 1.0 km/s . Seven of these were eventually
withdrawn as photometric false alarms based on an independent reanalysis using
more sophisticated tools. Of the remaining six, one was put aside because a
close visual companion proved to be a spectroscopic binary, and two were not
followed up because the host stars were judged to be too large. Two of the
remaining candidates are members of a visual binary, one of which was
previously confirmed as the first HATNet transiting planet, HAT-P-1b. In this
paper we confirm that the last of this set of candidates is also a a transiting
planet, which we designate HAT-P-8b, with mass Mp = 1.52 +/- 0.18/0.16 Mjup,
radius Rp = 1.50 +/- 0.08/0.06 Rjup, and photometric period P = 3.076320 +/-
0.000004 days. HAT-P-8b has an inflated radius for its mass, and a large mass
for its period. The host star is a solar-metallicity F dwarf, with mass M* =
1.28 +/- 0.04 Msun and Rp = 1.58 +/- 0.08/0.06 Rsun.Comment: 16 pages, 6 figures, 13 table
Refined stellar, orbital and planetary parameters of the eccentric HAT-P-2 planetary system
We present refined parameters for the extrasolar planetary system HAT-P-2
(also known as HD 147506), based on new radial velocity and photometric data.
HAT-P-2b is a transiting extrasolar planet that exhibits an eccentric orbit. We
present a detailed analysis of the planetary and stellar parameters, yielding
consistent results for the mass and radius of the star, better constraints on
the orbital eccentricity, and refined planetary parameters. The improved
parameters for the host star are M_star = 1.36 +/- 0.04 M_sun and R_star = 1.64
+/- 0.08 R_sun, while the planet has a mass of M_p = 9.09 +/- 0.24 M_Jup and
radius of R_p = 1.16 +/- 0.08 R_Jup. The refined transit epoch and period for
the planet are E = 2,454,387.49375 +/- 0.00074 (BJD) and P = 5.6334729 +/-
0.0000061 (days), and the orbital eccentricity and argument of periastron are e
= 0.5171 +/- 0.0033 and omega = 185.22 +/- 0.95 degrees. These orbital elements
allow us to predict the timings of secondary eclipses with a reasonable
accuracy of ~15 minutes. We also discuss the effects of this significant
eccentricity including the characterization of the asymmetry in the transit
light curve. Simple formulae are presented for the above, and these, in turn,
can be used to constrain the orbital eccentricity using purely photometric
data. These will be particularly useful for very high precision, space-borne
observations of transiting planets.Comment: Revised version, accepted for publication in MNRAS, 11 pages, 6
figure
The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b
We present the results of a transcontinental campaign to observe the 2009
June 5 transit of the exoplanet HD 80606b. We report the first detection of the
transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and
allowing more robust determinations of the system parameters. Keck spectra
obtained at midtransit exhibit an anomalous blueshift, giving definitive
evidence that the stellar spin axis and planetary orbital axis are misaligned.
The Keck data show that the projected spin-orbit angle is between 32-87 deg
with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the
orbit of this planet is not only highly eccentric (e=0.93), but is also tilted
away from the equatorial plane of its parent star. A large tilt had been
predicted, based on the idea that the planet's eccentric orbit was caused by
the Kozai mechanism. Independently of the theory, it is noteworthy that all 3
exoplanetary systems with known spin-orbit misalignments have massive planets
on eccentric orbits, suggesting that those systems migrate differently than
lower-mass planets on circular orbits.Comment: ApJ, in press [13 pg
Stellar Coronal and Wind Models: Impact on Exoplanets
Surface magnetism is believed to be the main driver of coronal heating and
stellar wind acceleration. Coronae are believed to be formed by plasma confined
in closed magnetic coronal loops of the stars, with winds mainly originating in
open magnetic field line regions. In this Chapter, we review some basic
properties of stellar coronae and winds and present some existing models. In
the last part of this Chapter, we discuss the effects of coronal winds on
exoplanets.Comment: Chapter published in the "Handbook of Exoplanets", Editors in Chief:
Juan Antonio Belmonte and Hans Deeg, Section Editor: Nuccio Lanza. Springer
Reference Work
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