7,391 research outputs found
Running Economy while Running in Extreme Cushioning and Normal Cushioning Running Shoes
The purpose of the study was to determine if running economy was influenced by wearing maximal cushioning shoes vs. control (neutral cushioning) shoes. (Please see Abstract in text
Investigation of effect of propulsion system installation and operation on aerodynamics of an airbreathing hypersonic airplane at Mach 0.3 to 1.2
Results from an investigation of the effects of the operation of a combined turbojet/scramjet propulsion system on the longitudinal aerodynamic characteristics of a 1/60-scale hypersonic airbreathing launch vehicle configuration are presented. Decomposition products of hydrogen peroxide were used for simulation of the propulsion system exhaust
The development of direct payments in the UK: implications for social justice
Direct payments have been heralded by the disability movement as an important means to
achieving independent living and hence greater social justice for disabled people through
enhanced recognition as well as financial redistribution. Drawing on data from the ESRC
funded project Disabled People and Direct Payments: A UK Comparative Perspective,
this paper presents an analysis of policy and official statistics on use of direct payments
across the UK. It is argued that the potential of direct payments has only partly been
realised as a result of very low and uneven uptake within and between different parts
of the UK. This is accounted for in part by resistance from some Labour-controlled local
authorities, which regard direct payments as a threat to public sector jobs. In addition,
access to direct payments has been uneven across impairment groups. However, from a
very low base there has been a rapid expansion in the use of direct payments over the
past three years. The extent to which direct payments are able to facilitate the ultimate
goal of independent living for disabled people requires careful monitoring
How to design and evaluate interventions to improve outcomes for patients with multimorbidity
Multimorbidity is a major challenge for patients and healthcare providers. The limited evidence of the effectiveness of interventions for people with multimorbidity means that there is a need for much more research and trials of potential interventions. Here we present a consensus view from a group of international researchers working to improve care for people with multimorbidity to guide future studies of interventions. We suggest that there is a need for careful consideration of whom to include, how to target interventions that address specific problems and that do not add to treatment burden, and selecting outcomes that matter both to patients and the healthcare system. Innovative design of these interventions will be necessary as many will be introduced in service settings and it will be important to ensure methodological rigour, relevance to service delivery, and generalizability across healthcare systems
Principal Components Analysis of Reflectance Spectra from the Mars Exploration Rover Opportunity
In the summer of 2007 a global dust storm on Mars effectively disabled Opportunity's Miniature Thermal Emission Spectrometer (Mini-TES), the primary instrument used by the Athena Science Team to identify locally unique rocks on the Martian surface. The science team needs another way to distinguish interesting rocks from their surroundings on a tactical timescale. This study was designed to develop the ability to identify locally unique rocks on the Martian surface remotely using the Mars Exploration Rovers' Panoramica Camera (PanCam) instrument. Meridiani bedrock observed by Opportunity is largely characterized by sulfate-rich sandstones and hematite spherules. Additionally, loose fragments of bedrock and "cobbles" of foreign origin collet on the surface, some of which are interpreted as meteorites
Principal Components Analysis of Reflectance Spectra Returned by the Mars Exploration Rover Opportunity
The Mars Exploration Rover Opportunity has spent over six years exploring the Martian surface near its landing site at Meridiani Planum. Meridiani bedrock observed by the rover is largely characterized by sulfate-rich sandstones and hematite spherules, recording evidence of ancient aqueous environments [1]. The region is a deflationary surface, allowing hematite spherules, fragments of bedrock, and "cobbles" of foreign origin to collect loosely on the surface. These cobbles may be meteorites (e.g., Barberton, Heat Shield Rock, Santa Catarina) [2], or rock fragments of exotic composition derived from adjacent terranes or from the subsurface and delivered to Meridiani Planum as impact ejecta [3]. The cobbles provide a way to better understand Martian meteorites and the lithologic diversity of Meridiani Planum by examining the various rock types located there. In the summer of 2007, a global dust storm on Mars effectively disabled Opportunity's Miniature Thermal Emission Spectrometer (Mini-TES), which served as the Athena Science Team s primary tool for remotely identifying rocks of interest on a tactical timescale for efficient rover planning. While efforts are ongoing to recover use of the Mini-TES, the team is currently limited to identifying rocks of interest by visual inspection of images returned from Opportunity's Panoramic Camera (Pancam). This study builds off of previous efforts to characterize cobbles at Meridiani Planum using a database of reflectance spectra extracted from Pancam 13-Filter (13F) images [3]. We analyzed the variability of rock spectra in this database and identified physical characteristics of Martian rocks that could potentially account for the observed variance. By understanding such trends, we may be able to distinguish between rock types at Meridiani Planum and regain the capability to remotely identify locally unique rocks
Forward-swept wing configuration designed for high maneuverability by use of a transonic computational method
A transonic computational analysis method and a transonic design procedure have been used to design the wing and the canard of a forward-swept-wing fighter configuration for good transonic maneuver performance. A model of this configuration was tested in the Langley 16-Foot Transonic Tunnel. Oil-flow photographs were obtained to examine the wind flow patterns at Mach numbers from 0.60 to 0.90. The transonic theory gave a reasonably good estimate of the wing pressure distributions at transonic maneuver conditions. Comparison of the forward-swept-wing configuration with an equivalent aft-swept-wing-configuration showed that, at a Mach number of 0.90 and a lift coefficient of 0.9, the two configurations have the same trimmed drag. The forward-swept wing configuration was also found to have trimmed drag levels at transonic maneuver conditions which are comparable to those of the HiMAT (highly maneuverable aircraft technology) configuration and the X-29 forward-swept-wing research configuration. The configuration of this study was also tested with a forebody strake
Analysis of enhanced diffusion in Taylor dispersion via a model problem
We consider a simple model of the evolution of the concentration of a tracer,
subject to a background shear flow by a fluid with viscosity in an
infinite channel. Taylor observed in the 1950's that, in such a setting, the
tracer diffuses at a rate proportional to , rather than the expected
rate proportional to . We provide a mathematical explanation for this
enhanced diffusion using a combination of Fourier analysis and center manifold
theory. More precisely, we show that, while the high modes of the concentration
decay exponentially, the low modes decay algebraically, but at an enhanced
rate. Moreover, the behavior of the low modes is governed by finite-dimensional
dynamics on an appropriate center manifold, which corresponds exactly to
diffusion by a fluid with viscosity proportional to
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Coding classroom dialogue: Methodological considerations for researchers
Systematic analysis or coding of classroom dialogue is useful for assessing the role of high-quality interaction in supporting learning. However, although coding is an immensely complex and cognitively demanding activity that has taxed researchers over decades, the methodological challenges are often not discussed or problematised in empirical reports. Accordingly, this paper aims to help researchers make sense of the challenges, strengths and practical applications of using systematic coding schemes for analysing classroom dialogue. It presents an in-depth analysis of the pros and cons of contrasting approaches and the key methodological considerations, including scope, grain size, reliability and validity. It goes on to provide a worked example, illustrating how one team tackled the challenges in adapting for a new research objective an earlier coding scheme developed for use across diverse contexts. Two original, theory-informed analytic tools created to study the relationship between dialogic teaching and student learning in English primary schools are shared and made available for others’ use or adaptation. The paper offers practical guidance for developing or adapting coding schemes for different research purposes. It highlights the need for further precision and critical attention to the ways in which scholars are investigating dialogic practices intended to support learning.ESR
Computations for the 16-foot transonic tunnel, NASA, Langley Research Center, revision 1
The equations used by the 16 foot transonic tunnel in the data reduction programs are presented in eight modules. Each module consists of equations necessary to achieve a specific purpose. These modules are categorized in the following groups: tunnel parameters; jet exhaust measurements; skin friction drag; balance loads and model attitudes calculations; internal drag (or exit-flow distributions); pressure coefficients and integrated forces; thrust removal options; and turboprop options. This document is a companion document to NASA TM-83186, A User's Guide to the Langley 16 Foot Transonic Tunnel, August 1981
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