682 research outputs found
Where, when, and how well people park: a phone survey and field measurements
AVM and Low Speed Maneuvers: Human Factors Issues ProjectTwo evaluations were completed to characterize where, how often, and how
accurately people normally park. A telephone survey of 30 drivers examined where
people park most frequently and the problems drivers have parking. The focus was on
executing maneuvers, not the availability of parking. Depending on how the question
was asked, approximately 74 to 84 percent of the parking events involved
perpendicular parking. Of the 8 parking-related crashes reported by subjects, 6
involved backing, usually with a vehicle traveling down an aisle or backing up from a
parking stall.
A field survey examined the parking accuracy of 102 vehicles in Ann Arbor,
Michigan, a college town. For parallel parking, drivers parked about 4 in from the curb
in spaces averaging 24 feet long. For angle parking, distances to the front of the
space were bimodal, with some drivers parking about 10 inches from the end of the
space and others overlapping by 10 in on average.
Overall, drivers parked slightly to the right of center (by 1 inch for parallel parking
and 4 inches for perpendicular parking) for 8.5 feet wide spaces. Yaw angles were
almost always less than 1 degree for perpendicular and angle parking, but as much as
3 degrees for parallel parking, which is a more difficult task.
The data from this experiment provide both a basis for establishing the conditions
for parking experiments and baseline data on how well people park without assistance.Nissan Research Centerhttp://deepblue.lib.umich.edu/bitstream/2027.42/87990/1/102765.pd
Pressure-dependent EPANET extension
In water distribution systems (WDSs), the available flow at a demand node is dependent on the pressure at that node. When a network is lacking in pressure, not all consumer demands will be met in full. In this context, the assumption that all demands are fully satisfied regardless of the pressure in the system becomes unreasonable and represents the main limitation of the conventional demand driven analysis (DDA) approach to WDS modelling. A realistic depiction of the network performance can only be attained by considering demands to be pressure dependent. This paper presents an extension of the renowned DDA based hydraulic simulator EPANET 2 to incorporate pressure-dependent demands. This extension is termed “EPANET-PDX” (pressure-dependent extension) herein. The utilization of a continuous nodal pressure-flow function coupled with a line search and backtracking procedure greatly enhance the algorithm’s convergence rate and robustness. Simulations of real life networks consisting of multiple sources, pipes, valves and pumps were successfully executed and results are presented herein. Excellent modelling performance was achieved for analysing both normal and pressure deficient conditions of the WDSs. Detailed computational efficiency results of EPANET-PDX with reference to EPANET 2 are included as well
Defining sustainable transport in rural tourism: experiences from the New Forest
Transport policy agendas have long sought to bring about more sustainable transport at tourism destinations. While there are examples of successes, it remains unclear what inroads have been made towards creating a sustainable transport future. Policy directions have evolved over a number of years and in many tourism destination contexts it is far from clear what a desirable transport future looks like. When translated to implementation, the aims of initiatives can be unclear and baseline measures inconsistent, making success difficult to judge. This paper analyses how sustainable travel has been implemented in practice at a destination level. The focus is rural tourism and data are derived from a specific case, the New Forest National Park, UK, where a wide range of transport initiatives have been implemented since the Park’s designation in 2005. The study adopts a social practice theory perspective. Data are derived from a visitor survey, interviews and observations. It finds there is scope to improve sustainable transport provision at destinations through understanding visitor practices, but limited scope to influence meanings associated with visitor travel and travel skills. Policy meets the needs of some visitors more than others
The Magellanic Edges Survey IV. Complex tidal debris in the SMC outskirts
ABSTRACT
We use data from the Magellanic Edges Survey (MagES) in combination with Gaia EDR3 to study the extreme southern outskirts of the Small Magellanic Cloud (SMC), focussing on a field at the eastern end of a long arm-like structure which wraps around the southern periphery of the Large Magellanic Cloud (LMC). Unlike the remainder of this structure, which is thought to be comprised of perturbed LMC disc material, the aggregate properties of the field indicate a clear connection with the SMC. We find evidence for two stellar populations in the field: one having properties consistent with the outskirts of the main SMC body, and the other significantly perturbed. The perturbed population is on average ∼0.2 dex more metal-rich, and is located ∼7 kpc in front of the dominant population with a total space velocity relative to the SMC centre of ∼230 km s−1 broadly in the direction of the LMC. We speculate on possible origins for this perturbed population, the most plausible of which is that it comprises debris from the inner SMC that has been recently tidally stripped by interactions with the LMC.</jats:p
The Magellanic Edges Survey III. Kinematics of the disturbed LMC outskirts
We explore the structural and kinematic properties of the outskirts of the
Large Magellanic Cloud (LMC) using data from the Magellanic Edges Survey
(MagES) and Gaia EDR3. Even at large galactocentric radii
(), we find the north-eastern LMC disk is relatively
unperturbed: its kinematics are consistent with a disk of inclination
~ and line-of-nodes position angle ~ east of north. In
contrast, fields at similar radii in the southern and western disk are
significantly perturbed from equilibrium, with non-zero radial and vertical
velocities, and distances significantly in front of the disk plane implied by
our north-eastern fields. We compare our observations to simple dynamical
models of the Magellanic/Milky Way system which describe the LMC as a
collection of tracer particles within a rigid potential, and the Small
Magellanic Cloud (SMC) as a rigid Hernquist potential. A possible SMC crossing
of the LMC disk plane ~400 Myr ago, in combination with the LMC's infall to the
Milky Way potential, can qualitatively explain many of the perturbations in the
outer disk. Additionally, we find the claw-like and arm-like structures south
of the LMC have similar metallicities to the outer LMC disk ([Fe/H]~-1), and
are likely comprised of perturbed LMC disk material. The claw-like substructure
is particularly disturbed, with out-of-plane velocities >60 km s and
apparent counter-rotation relative to the LMC's disk motion. More detailed
N-body models are necessary to elucidate the origin of these southern features,
potentially requiring repeated interactions with the SMC prior to ~1 Gyr ago.Comment: Accepted by MNRA
The Magellanic Edges Survey II. Formation of the LMC's northern arm
The highly-substructured outskirts of the Magellanic Clouds provide ideal
locations for studying the complex interaction history between both Clouds and
the Milky Way (MW). In this paper, we investigate the origin of a >20
long arm-like feature in the northern outskirts of the Large Magellanic Cloud
(LMC) using data from the Magellanic Edges Survey (MagES) and Gaia EDR3. We
find that the arm has a similar geometry and metallicity to the nearby outer
LMC disk, indicating that it is comprised of perturbed disk material. Whilst
the azimuthal velocity and velocity dispersions along the arm are consistent
with those in the outer LMC, the in-plane radial velocity and out-of-plane
vertical velocity are significantly perturbed from equilibrium disk kinematics.
We compare these observations to a new suite of dynamical models of the
Magellanic/MW system, which describe the LMC as a collection of tracer
particles within a rigid potential, and the SMC as a rigid Hernquist potential.
Our models indicate the tidal force of the MW during the LMC's infall is likely
responsible for the observed increasing out-of-plane velocity along the arm.
Our models also suggest close LMC/SMC interactions within the past Gyr,
particularly the SMC's pericentric passage ~150 Myr ago and a possible SMC
crossing of the LMC disk plane ~400 Myr ago, likely do not perturb stars that
today comprise the arm. Historical interactions with the SMC prior to ~1 Gyr
ago may be required to explain some of the observed kinematic properties of the
arm, in particular its strongly negative in-plane radial velocity.Comment: Accepted by MNRA
Community-Based OT Program Planning: A Virtual Level II Fieldwork Program Developed in Response to the Global Pandemic
The purpose of this article is to explain how an occupational therapy (OT) program in a university setting developed a virtual Level II community-based fieldwork program in response to the COVID-19 global pandemic. This virtual fieldwork program, guided by the PRECEDE-PROCEED Planning Model (PPM), was designed to help keep students on track with their academic goals while providing them with experiential learning that would increase their confidence in OT program planning and promote their professional development. Outcome measures for this study consisted of a pre-and post-fieldwork survey that asked participants to rank their self-perceived confidence in five distinct areas of community-based OT program development. Some portions of Section III in the Student’s Evaluation of the Fieldwork Experience (SEFWE) form were also used to examine students’ feedback after participating in this virtual fieldwork program. Retrospective data analysis of pre-post survey results showed improvements in students’ perceived confidence with certain aspects of OT program development in community settings. Within the core function of program development, occupation-based approaches to community-based programs can be used to inform, educate, and empower people and populations about important health issues while simultaneously offering students rich opportunities for professional development and identity. Dissemination of this information can be helpful to other OT professionals who are developing alternate fieldwork programs in response to the pandemic and beyond
The Magellanic Edges Survey I. Description and First Results
We present an overview of, and first science results from, the Magellanic
Edges Survey (MagES), an ongoing spectroscopic survey mapping the kinematics of
red clump and red giant branch stars in the highly substructured periphery of
the Magellanic Clouds. In conjunction with Gaia astrometry, MagES yields a
sample of ~7000 stars with individual 3D velocities that probes larger
galactocentric radii than most previous studies. We outline our target
selection, observation strategy, data reduction and analysis procedures, and
present results for two fields in the northern outskirts ( on-sky
from the centre) of the Large Magellanic Cloud (LMC). One field, located in the
vicinity of an arm-like overdensity, displays apparent signatures of
perturbation away from an equilibrium disk model. This includes a large radial
velocity dispersion in the LMC disk plane, and an asymmetric line-of-sight
velocity distribution indicative of motions vertically out of the disk plane
for some stars. The second field reveals 3D kinematics consistent with an
equilibrium disk, and yields km s at a
radial distance of ~10.5kpc from the LMC centre. This leads to an enclosed mass
estimate for the LMC at this radius of
.Comment: 23 pages, 10 figures. Accepted by MNRA
Pelvic trauma : WSES classification and guidelines
Complex pelvic injuries are among the most dangerous and deadly trauma related lesions. Different classification systems exist, some are based on the mechanism of injury, some on anatomic patterns and some are focusing on the resulting instability requiring operative fixation. The optimal treatment strategy, however, should keep into consideration the hemodynamic status, the anatomic impairment of pelvic ring function and the associated injuries. The management of pelvic trauma patients aims definitively to restore the homeostasis and the normal physiopathology associated to the mechanical stability of the pelvic ring. Thus the management of pelvic trauma must be multidisciplinary and should be ultimately based on the physiology of the patient and the anatomy of the injury. This paper presents the World Society of Emergency Surgery (WSES) classification of pelvic trauma and the management Guidelines.Peer reviewe
- …
