14,033 research outputs found
I'M A visual thinker: Rethinking algorithmic education for architectural design
© 2016, The Association for Computer-Aided Architectural Design Research in Asia (CAADRIA), Hong Kong. The representational and visual aspects of architectural design education cause certain pedagogical stresses in student's capacities to learn how to code, and this paper will serve as a critique of the current state of algorithmic pedagogy in architectural education. The paper will suggest that algorithmic curriculum should not frame code as 'a design tool', but as something to be designed in its own right; the writing of the code is the 'design brief' itself and not something additional to an architectural design brief. The paper will argue for an architecture- less educational environment that focuses on computational competencies such as logic, loops and lists along with building a strong analytical basis for students' understanding of programming and digital geometries
Comparative Surface Heat Transfer Measurements in Hypervelocity Flow
Reliable prediction of the high heat transfer rates experienced
during the hypersonic portion of planetary entry and descent is
critical to vehicle survival. Two types of sensors that can be used to
measure surface heat flux are coaxial thermocouple gages and thin
film resistance thermometers. Individually, both types of gages have
been used successfully in a number of studies [1–19]. Both
thermocouple and thin film gages measure surface temperature from
which heat transfer can be calculated. Both have µs response times,
and can be flush-mounted in models. Coaxial thermocouples are
robust, can survive challenging experimental conditions, and are
typically used in higher enthalpy flows. Thin film resistance gages
typically provide improved signal levels, but are less robust, have to
be individually calibrated, and are typically used in lower enthalpy
flows. As a result, there are few studies which directly compare
measurements from the two types of gages. In the present work, we
perform experimental measurements at a range of intermediate
enthalpies in hypervelocity flow and make direct comparisons
between temperature histories and heat flux data obtained from
thermocouple and thin film gages
Scaling of heat transfer augmentation due to mechanical distortions in hypervelocity boundary layers
We examine the response of hypervelocity boundary layers to global mechanical distortions due to concave surface curvature. Surface heat transfer and visual boundary layer thickness data are obtained for a suite of models with different concave surface geometries. Results are compared to predictions using existing approximate methods. Near the leading edge, good agreement is observed, but at larger pressure gradients, predictions diverge significantly from the experimental data. Up to a factor of five underprediction is reported in regions with greatest distortion. Curve fits to the experimental data are compared with surface equations. We demonstrate that reasonable estimates of the laminar heat flux augmentation may be obtained as a function of the local turning angle for all model geometries, even at the conditions of greatest distortion. This scaling may be explained by the application of Lees similarity. As a means of introducing additional local distortions, vortex generators are used to impose streamwise structures into the boundary layer. The response of the large scale vortices to an adverse pressure gradient is investigated. Surface streak evolution is visualized over the different surface geometries using fast response pressure sensitive paint. For a flat plate baseline case, heat transfer augmentation at similar levels to turbulent flow is measured. For the concave geometries, increases in heat transfer by factors up to 2.6 are measured over the laminar values. The scaling of heat transfer with turning angle that is identified for the laminar boundary layer response is found to be robust even in the presence of the imposed vortex structures
Two- and three-dimensional simulations of core-collapse supernovae with CHIMERA
Ascertaining the core-collapse supernova mechanism is a complex, and yet
unsolved, problem dependent on the interaction of general relativity,
hydrodynamics, neutrino transport, neutrino-matter interactions, and nuclear
equations of state and reaction kinetics. Ab initio modeling of core-collapse
supernovae and their nucleosynthetic outcomes requires care in the coupling and
approximations of the physical components. We have built our multi-physics
CHIMERA code for supernova modeling in 1-, 2-, and 3-D, using ray-by-ray
neutrino transport, approximate general relativity, and detailed neutrino and
nuclear physics. We discuss some early results from our current series of
exploding 2D simulations and our work to perform computationally tractable
simulations in 3D using the "Yin-Yang" grid.Comment: Proceedings of the 12th Symposium on Nuclei in the Cosmos. 5-12
August 2012. Cairns, Australia. Published online at
http://pos.sissa.it/archive/conferences/146/208/NIC%20XII_208.pdf Corrected
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Commentary : Fatty acids, breastfeeding and Autism Spectrum Disorder
Fatty acid deficiencies are linked to Autism Spectrum Disorder. This commentary discusses the protective role of breastfeeding and the urgency of research into the human infant\u27s intake of colostrum to prevent fatty acid deficiency
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How Media Literacy, Trust of Experts and Flu Vaccine Behaviors Associated with COVID-19 Vaccine Intentions
To assess how previous experiences and new information contributed to COVID-19 vaccine intentions. Online survey (N = 1264) with quality checks. Cross-sectional U.S. survey fielded June 22-July 18, 2020. U.S. residents 18+; quotas reflecting U.S. Census, limited to English speakers participating in internet panels. Media literacy for news content and sources, COVID-19 knowledge; perceived usefulness of health experts; if received flu vaccine in past 12 months; vaccine willingness scale; demographics. Structural equation modelling. Perceived usefulness of health experts ( = .422, < .001) and media literacy ( = .162, < .003) predicted most variance in vaccine intentions (R-squared=31.5%). A significant interaction ( = .163, < .001) between knowledge ( = -.132, = .052) and getting flu shot ( = .185, < .001) predicted additional 3.5% of the variance in future vaccine intentions. An increase in knowledge of COVID-19 associated with a decrease in vaccine intention among those declining the flu shot. The interaction result suggests COVID-19 knowledge had a positive association with vaccine intention for flu shot recipients but a counter-productive association for those declining it. Media literacy and trust in health experts provided strong counterbalancing influences. Survey-based findings are correlational; thus, predictions are based on theory. Future research should study these relationships with panel data or experimental designs
Unsteady high-pressure flow experiments with applications to explosive volcanic eruptions
Motivated by the hypothesis that volcanic blasts can have supersonic regions, we investigate the role of unsteady flow in jets from a high-pressure finite reservoir. We examine the processes for formation of far-field features, such as Mach disk shocks, by using a shock tube facility and numerical experiments to investigate phenomena to previously unobtained pressure ratios of 250:1. The Mach disk shock initially forms at the edges of the vent and moves toward the centerline. The shock is established within a few vent diameters and propagates downstream toward the equilibrium location as the jet develops. The start-up process is characterized by two different timescales: the duration of supersonic flow at the nozzle exit and the formation time of the Mach disk shock. The termination process also is characterized by two different timescales: the travel time required for the Mach disk shock to reach its equilibrium position and the time at which the Mach disk shock begins significantly to collapse away from its equilibrium position. The critical comparisons for the formation of steady state supersonic regions are between the two start-up timescales and the termination timescales. We conclude that for typical vulcanian eruptions and the Mount St. Helens directed blast, the Mach disk shock could have formed near the vent, and that there was time for it to propagate a distance comparable to its equilibrium location. These experiments provide a framework for analysis of short-lived volcanic eruptions and data for benchmarking simulations of jet structures in explosive volcanic blasts
Experimental simulations of the May 18, 1980 directed blast at Mount St. Helens, WA
The 1980 directed blast at Mount St. Helens erupted from a high-pressure magma chamber into atmospheric conditions at a pressure ratio of ~150:1, producing a high-velocity dusty gas flow. Decompression from even modestly high pressure ratios (>2:1) produces supersonic flow and thus, this event was modeled as a supersonic underexpanded jet by Kieffer (1981). Steady-state underexpanded jets have a complex geometrical structure in which there is an abrupt, stationary, normal shock wave, called the Mach disk shock. For steady flow, a log-linear relationship between pressure ratio and Mach disk standoff distance, known as the Ashkenas-Sherman relation, is valid for pressure ratios above 15:1 given by x/D=0.67(Rp)^(0.5) where Rp is the pressure ratio, and x/D is the standoff distance normalized to vent diameter. The effects of unsteady discharge from a finite reservoir and application to Mount St. Helens have not been previously investigated. In order to simulate the blast, we use laboratory and numerical experiments of unsteady flow from a finite reservoir to examine jet structure. The reservoir and test section correspond to the magma chamber and ambient atmospheric conditions at Mount St. Helens respectively. We completed a series of laboratory experiments in which we varied the initial pressure ratio, reservoir length and reservoir gas (nitrogen, helium). The numerical simulations show that the Mach disk initially forms close to the vent and then travels downstream to its equilibrium position. The experiments show that as the reservoir pressure continuously decreases during the venting, or “blowdown”, the Mach disk shock continuously moves back toward the reservoir after its formation at the equilibrium position. Results of these experiments indicate that above a pressure ratio of 15:1, the Mach disk standoff distance for unsteady flow falls on the empirical Ashkenas-Sherman curve for steady flow. We present a new relation for the location of the Mach disk shock for pressure ratios below 15:1 given by x/D=0.41(Rp)^(0.66). The results indicate no dependence of the normalized Mach disk location on the finiteness of the reservoir. These results may be of interest not only for high pressure eruptions such as Mount St. Helens, but to low pressure steam eruptions as well because helium is a good analog to steam
Nudges and other moral technologies in the context of power: Assigning and accepting responsibility
Strawson argues that we should understand moral responsibility in terms of our practices of holding responsible and taking responsibility. The former covers what is commonly referred to as backward-looking responsibility , while the latter covers what is commonly referred to as forward-looking responsibility . We consider new technologies and interventions that facilitate assignment of responsibility. Assigning responsibility is best understood as the second- or third-personal analogue of taking responsibility. It establishes forward-looking responsibility. But unlike taking responsibility, it establishes forward-looking responsibility in someone else. When such assignments are accepted, they function in such a way that those to whom responsibility has been assigned face the same obligations and are susceptible to the same reactive attitudes as someone who takes responsibility. One family of interventions interests us in particular: nudges. We contend that many instances of nudging tacitly assign responsibility to nudgees for actions, values, and relationships that they might not otherwise have taken responsibility for. To the extent that nudgees tacitly accept such assignments, they become responsible for upholding norms that would otherwise have fallen under the purview of other actors. While this may be empowering in some cases, it can also function in such a way that it burdens people with more responsibility that they can (reasonably be expected to) manage
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