266 research outputs found
Let\u27s Talk About Ethics! A Qualitative Analysis of First-year Engineering Student Group Discussions Around Ethical Scenarios
Over the past decade, there has been a renewed interest in the scope and practice of ethics education in engineering curricula, especially in the first year. However, the form this education takes has varied considerably with each program. Active learning strategies such as discussions on ethical and societal issues have become increasingly common for assessing how students make ethical decisions. But probing the depths of the reasoning behind their decisions and how students discuss ethics in context with their peers has been under-studied and difficult. Furthermore, if first-year programs wish to implement effective instructional interventions aimed at improving ethical decision making skills, pre-assessment of student thought processes is required. This full research paper offers findings from the first phase of a multi-university research project, aimed at investigating the impact game-based instruction can have on the development of engineering students’ ethical awareness and decision making. Specifically, the research presented in this paper is guided by the following research question: How do engineering students reason through engineering-ethical scenarios prior to college-level ethics education? First-year engineering students across three universities in the northeast USA will participate in group discussions around engineering ethical scenarios derived from the Engineering Ethics Reasoning Instrument (EERI) and Toxic Workplaces: A Cooperative Ethics Card Game (developed by the researchers). The questions posed to the student groups center around primary morality concepts such as integrity, conflicting obligations, and the contextual nature of ethical decision making. An a priori coding schema based on these concepts will be utilized, along with an inductive thematic analysis to tease out emergent themes. Results from this research will provide insight into how first-year engineering students think and discuss ethics prior to formal instruction, which can inform curricular design and development strategy. The research also provides a curated series of ethical engineering scenarios with accompanying discussion questions that can be adopted in any first-year classroom for instructional and evaluative purposes
Integrating Entrepreneurial Mindset in a Multidisciplinary Course on Engineering Design and Technical Communication
The engineering curriculum at XXXX University includes a sophomore level two-course sequence (required for engineering students in all disciplines) in which the primary learning outcomes are engineering design and technical communication. These courses are team-taught by faculty from Engineering and from Communications, specifically, Writing Arts in the fall and Public Speaking in the spring. Historically, the fall course has featured three major course deliverables: (1) a “research sequence” consisting of a rhetorical analysis, and annotated bibliography and a literature review, (2) a humanities assignment in which students explore the impact of technology on societal needs, and (3) laboratory and design reports stemming from hands-on engineering projects completed in lab. During the summer of 2019, the faculty team re-designed each of these three major course deliverables, with the goal of fostering an Entrepreneurial Mindset in students and leveraging synergies between the Entrepreneurial Mindset and the existing goals of the course (engineering design and technical communication). In particular, the faculty team created a new linkage between the research sequence and the humanities assignment. The research sequence is built around the U.N.’s Sustainable Development Goals; each student chooses one of the goals to explore through their individual rhetorical analysis, annotated bibliography, and literature review. The humanities assignment is a team project in which students explore solutions to sustainability problems on the campus of XXXX University. Different sections of the course will use different engineering projects, but the faculty team has crafted a set of guidelines for the projects to ensure some uniformity of experience and expectations across the sections. The faculty team also developed rubrics that will be used to evaluate student performance on these re-designed assignments. The new assignments are being integrated into the Fall 2019 offering of Sophomore Engineering Clinic. This paper will give a detailed description of each of the assignments and how they are designed to align with the goal of fostering an Entrepreneurial Mindset. The paper will also present assessment data that will be collected throughout the Fall 2019 semester
An HST/WFPC2 Survey for Brown Dwarf Binaries in the alpha Per and the Pleiades Open Clusters
We present the results of a high-resolution imaging survey for brown dwarf
(BD) binaries in two open clusters. The observations were carried out with
WFPC2 onboard HST. Our sample consists of 8 BD candidates in the alpha Per
cluster and 25 BD candidates in the Pleiades. We have resolved 4 binaries in
the Pleiades with separations in the range 0".094--0".058, corresponding to
projected separations between 11.7~AU and 7.2~AU. No binaries were found among
the alpha Per targets. Three of the binaries have proper motions consistent
with cluster membership in the Pleiades cluster, and for one of them we report
the detection of Halpha in emission and LiI absorption obtained from
Keck~II/ESI spectroscopy. One of the binaries does not have a proper motion
consistent with Pleiades membership. We estimate that BD binaries wider than
12~AU are less frequent than 9% in the alphaPer and Pleiades clusters. This is
consistent with an extension to substellar masses of a trend observed among
stellar binaries: the maximum semimajor axis of binary systems decreases with
decreasing primary mass. We find a binary frequency of 2 binaries over 13 BDs
with confirmed proper motion membership in the Pleiades, corresponding to a
binary fraction of 15%(1 sigma error bar +15%/-5%). These binaries are limited
to the separation range 7-12~AU and their mass ratios are larger than 0.7. The
relatively high binary frequency (>10%), the bias to separations smaller than
about 15 AU and the trend to high mass ratios (q>0.7) are fundamental
properties of BDs. Current theories of BD formation do not appear to provide a
good description of all these properties.Comment: Accepted by ApJ (scheduled publication in volume 594, September 1,
2003
Astrometry and Photometry for 1000 L, T, and Y Dwarfs from the UKIRT Hemisphere Survey
We present positions, proper motions, and near-infrared photometry for 966
known objects with spectral types later than M observed as part of the the
UKIRT Hemisphere Survey (UHS). We augment the photometry and astrometry from
UHS with information from Gaia DR3, Pan-STARRS DR2, and CatWISE 2020 to produce
a database of homogeneous photometry and astrometry for this sample. The
multi-epoch survey strategy of UHS allows us to determine proper motions for
most sources, with a median proper motion uncertainty of 3.6 mas
yr. Our UHS proper motion measurements are generally in good agreement
with those from Gaia DR3, Pan-STARRS, and CatWISE 2020, with UHS proper motions
typically more precise than those from CatWISE 2020 and Pan-STARRS but not Gaia
DR3. We critically analyze publicly available spectra for 406 members of this
sample and provide updated near-infrared spectral types for 100 objects.
We determine typical colors as a function of spectral type and provide absolute
magnitude vs. spectral type relations for UHS - and -band photometry.
Using newly determined proper motions, we highlight several objects of
interest, such as objects with large tangential velocities, widely separated
co-moving companions, and potential members of young nearby associations.Comment: Accepted to A
Keck/NIRC2 Imaging of the Warped, Asymmetric Debris Disk around HD 32297
We present Keck/NIRC2 band high-contrast coronagraphic imaging of the
luminous debris disk around the nearby, young A star HD 32297 resolved at a
projected separation of = 0.3-2.5\arcsec{} ( 35-280 AU). The disk
is highly warped to the north and exhibits a complex, "wavy" surface brightness
profile interior to 110 AU, where the peaks/plateaus in the
profiles are shifted between the NE and SW disk lobes. The SW side of the disk
is 50--100% brighter at = 35-80 AU, and the location of its peak brightness
roughly coincides with the disk's mm emission peak. Spectral energy
distribution modeling suggests that HD 32297 has at least two dust populations
that may originate from two separate belts likely at different locations,
possibly at distances coinciding with the surface brightness peaks. A disk
model for a single dust belt including a phase function with two components and
a 5-10 AU pericenter offset explains the disk's warped structure and reproduces
some of the surface brightness profile's shape (e.g. the overall "wavy"
profile, the SB peak/plateau shifts) but more poorly reproduces the disk's
brightness asymmetry. Although there may be alternate explanations, agreement
between the SW disk brightness peak and disk's peak mm emission is consistent
with an overdensity of very small, sub-blowout-sized dust and large, 0.1-1
mm-sized grains at 45 AU tracing the same parent population of
planetesimals. New near-IR and submm observations may be able to clarify
whether even more complex grain scattering properties or dynamical sculpting by
an unseen planet are required to explain HD 32297's disk structure.Comment: 19 pages, 12 figures; ApJ in press (no text changes from previous
version
Pre-main sequence stars in the Cepheus flare region
We present results of optical spectroscopic and BVR_CI_C photometric
observations of 77 pre-main sequence (PMS) stars in the Cepheus flare region. A
total of 64 of these are newly confirmed PMS stars, originally selected from
various published candidate lists. We estimate effective temperatures and
luminosities for the PMS stars, and comparing the results with pre-main
sequence evolutionary models we estimate stellar masses of 0.2-2.4M_sun and
stellar ages of 0.1-15 Myr. Among the PMS stars, we identify 15 visual binaries
with separations of 2-10 arcsec. From archival IRAS, 2MASS, and Spitzer data,
we construct their spectral energy distributions and classify 5% of the stars
as Class I, 10% as Flat SED, 60% as Class II, and 3% as Class III young stellar
objects (YSOs). We identify 12 CTTS and 2 WTTS as members of NGC 7023, with
mean age of 1.6 Myr. The 13 PMS stars associated with L1228 belong to three
small aggregates: RNO 129, L1228A, and L1228S. The age distribution of the 17
PMS stars associated with L1251 suggests that star formation has propagated
with the expansion of the Cepheus flare shell. We detect sparse aggregates of
6-7 Myr old PMS stars around the dark clouds L1177 and L1219, at a distance of
400 pc. Three T Tauri stars appear to be associated with the Herbig Ae star SV
Cep at a distance of 600 pc. Our results confirm that the molecular complex in
the Cepheus flare region contains clouds of various distances and star forming
histories.Comment: 61 pages, 27 figures, 8 tables; accepted for publication by ApJ
Deep MIPS Observations of the IC 348 Nebula: Constraints on the Evolutionary State of Anemic Circumstellar Disks and the Primordial-to-Debris Disk Transition
We describe new, deep MIPS photometry and new high signal-to-noise optical
spectroscopy of the 2.5 Myr-old IC 348 Nebula. To probe the properties of the
IC 348 disk population, we combine these data with previous optical/infrared
photometry and spectroscopy to identify stars with gas accretion, to examine
their mid-IR colors,and to model their spectral energy distributions. IC 348
contains many sources in different evolutionary states, including protostars
and stars surrounded by primordial disks, two kinds of transitional disks, and
debris disks. Most disks surrounding eary/intermediate spectral-type stars (>
1.4 Msun at 2.5 Myr) are debris disks; most disks surrounding solar and
subsolar-mass stars are primordial disks. At the 1--2 sigma level, more massive
stars also have a smaller frequency of gas accretion and smaller mid-IR
luminosities than lower-mass stars. These trends are suggestive of a stellar
mass-dependent evolution of disks, where most disks around
high/intermediate-mass stars shed their primordial disks on rapid, 2.5 Myr
timescales. The frequency of MIPS-detected transitional disks is ~ 15--35% for
stars plausibly more massive than 0.5 Msun. The relative frequency of
transitional disks in IC 348 compared to that for 1 Myr-old Taurus and 5
Myr-old NGC 2362 is consistent with a transition timescale that is a
significant fraction of the total primordial disk lifetime.Comment: 53 pages, 14 figures; 6 tables; accepted for publication in the
Astronomical Journa
The X-Ray Environment During the Epoch of Terrestrial Planet Formation: Chandra Observations of h Persei
We describe Chandra/ACIS-I observations of the massive ~ 13--14 Myr-old
cluster, h Persei, part of the famous Double Cluster (h and chi Persei) in
Perseus. Combining the list of Chandra-detected sources with new optical/IR
photometry and optical spectroscopy reveals ~ 165 X-ray bright stars with V <
23. Roughly 142 have optical magnitudes and colors consistent with cluster
membership. The observed distribution of Lx peaks at Lx ~ 10^30.3 ergs/s and
likely traces the bright edge of a far larger population of ~ 0.4--2 Msun X-ray
active stars. From a short list of X-ray active stars with IRAC 8 micron excess
from warm, terrestrial-zone dust, we derive a maximum X-ray flux incident on
forming terrestrial planets. Although there is no correlation between X-ray
activity and IRAC excess, the fractional X-ray luminosity correlates with
optical colors and spectral type. By comparing the distribution of Lx/L* vs.
spectral type and V-I in h Per with results for other 1--100 Myr-old clusters,
we show that stars slightly more massive than the Sun (> 1.5 Msun) fall out of
X-ray saturation by ~ 10--15 Myr. Changes in stellar structure for > 1.5 Msun
stars likely play an important role in this decline of X-ray emission.Comment: 34 pages, 7 Figures, 2 Tables; Accepted for publication in The
Astronomical Journa
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