17,183 research outputs found
An evaluation of the total quality management implementation strategy for the advanced solid rocket motor project at NASA's Marshall Space Flight Center
An evaluation of the NASA's Marshall Space Flight Center (MSFC) strategy to implement Total Quality Management (TQM) in the Advanced Solid Rocket Motor (ASRM) Project is presented. The evaluation of the implementation strategy reflected the Civil Service personnel perspective at the project level. The external and internal environments at MSFC were analyzed for their effects on the ASRM TQM strategy. Organizational forms, cultures, management systems, problem solving techniques, and training were assessed for their influence on the implementation strategy. The influence of ASRM's effort was assessed relative to its impact on mature projects as well as future projects at MSFC
An analysis of bi-directional use of frequencies for satellite communications
The bi-directional use of frequencies allocated for space communications has the potential to double the orbit/spectrum capacity available. The technical feasibility of reverse band use (RBU) at C-band (4 GHz uplinks and 6 GHz downlinks) is studied. The analysis identifies the constraints under which both forward and reverse band use satellite systems can share the same frequencies with terrestrial, line of sight transmission systems. The results of the analysis show that RBU satellite systems can be similarly sized to forward band use (FBU) satellite systems. In addition, the orbital separation requirements between RBU and FBU satellite systems are examined. The analysis shows that a carrier to interference ratio of 45 dB can be maintianed between RBU and FBU satellites separated by less than 0.5 deg., and that a carrier to interference ratio of 42 dB can be maintained in the antipodal case. Rain scatter propagation analysis shows that RBU and FBU Earth stations require separation distances fo less than 10 km at a rain rate of 13.5 mm/hr escalating to less than 100 km at a rain rate of 178 mm/hr for Earth station antennas in the 3 to 10 m range
Ascertaining the Impact of P–12 Engineering Education Initiatives: Student Impact through Teacher Impact
The widespread need to address both science, technology, engineering, and math (STEM) education and STEM workforce development is persistent. Underscored by the Next Generation Science Standards, demand is high for P–12 engineering-centered curricula. TeachEngineering is a free, standards-aligned NSF-funded digital library of more than 1,500 hands-on, design-rich K–12 engineering lessons and activities. Beyond anonymous site-user counts, the impact of the TeachEngineering collection and outreach initiatives on the education of children and their teachers was previously unknown. Thus, the project team wrestled with the question of how to meaningfully ascertain classroom impacts of the digital engineering education library and—more broadly—how to ascertain the impacts of teacher-focused P–12 engineering education initiatives. In this paper, the authors approach the classroom impact question through probing self-reported differentials in: (1) teachers’ confidence in teaching engineering concepts, and (2) changes in their teaching practices as a result of exposure to (and experiences with) K–12 engineering education resources and outreach opportunities. In 2016, four quantitative and qualitative surveys were implemented to probe the impact of the TeachEngineering digital library and outreach on four populations of K–12 teachers’ confidence and practices, including the frequency with which they integrate engineering into their precollege classrooms. Survey results document the teacher experience and perception of using hands-on K–12 engineering curricular materials in the classroom and help create a data-driven understanding of where to best invest future resources. The results suggest that the TeachEngineering curricular resources and outreach initiatives help teachers build confidence in their use of engineering curriculum and pedagogy in K–12 classrooms, impact their teaching practices, and increase their likelihood of teaching engineering in the classroom in the future
Leadership Adaptability Within Higher Education
Dynamism in the higher education industry (HEI) has created unprecedented complexity and uncertainty for leaders at colleges and universities across the globe. The challenges to competitive advantage and sustainability created by dynamic conditions have been exacerbated and accelerated by the COVID-19 pandemic and health crisis. HEI leaders are struggling to adapt antiquated and traditionally held methods and practices to navigate the rapid changes and survive the resulting chaos. The ability of leaders to adapt to dynamism in contemporary industry conditions is influenced by the external and internal environments; in term, these leaders’ capacity for change impacts the adaptability of the institutions they serve. This study examines how senior- and mid-level leaders at small private liberal arts colleges and universities are engaging in adaptive behaviors to help their organizations better compete despite challenges
Spaces of finite element differential forms
We discuss the construction of finite element spaces of differential forms
which satisfy the crucial assumptions of the finite element exterior calculus,
namely that they can be assembled into subcomplexes of the de Rham complex
which admit commuting projections. We present two families of spaces in the
case of simplicial meshes, and two other families in the case of cubical
meshes. We make use of the exterior calculus and the Koszul complex to define
and understand the spaces. These tools allow us to treat a wide variety of
situations, which are often treated separately, in a unified fashion.Comment: To appear in: Analysis and Numerics of Partial Differential
Equations, U. Gianazza, F. Brezzi, P. Colli Franzone, and G. Gilardi, eds.,
Springer 2013. v2: a few minor typos corrected. v3: a few more typo
correction
Ultralocality and Slow Contraction
We study the detailed process by which slow contraction smooths and flattens the universe using an improved numerical relativity code that accepts initial conditions with non-perturbative deviations from homogeneity and isotropy along two independent spatial directions. Contrary to common descriptions of the early universe, we find that the geometry first rapidly converges to an inhomogeneous, spatially-curved and anisotropic ultralocal state in which all spatial gradient contributions to the equations of motion decrease as an exponential in time to negligible values. This is followed by a second stage in which the geometry converges to a homogeneous, spatially flat and isotropic spacetime. In particular, the decay appears to follow the same history whether the entire spacetime or only parts of it are smoothed by the end of slow contraction
Electrodynamics of Media
Contains reports on two research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)U.S. Air Force (ESD) Contract F19628-70-C-006
Understanding single-top-quark production and jets at hadron colliders
I present an analysis of fully differential single-top-quark production plus
jets at next-to-leading order. I describe the effects of jet definitions,
top-quark mass, and higher orders on the shapes and normalizations of the
kinematic distributions, and quantify all theoretical uncertainties. I explain
how to interpret next-to-leading-order jet calculations, and compare them to
showering event generators. Using the program ZTOP, I show that HERWIG and
PYTHIA significantly underestimate both s-channel and t-channel
single-top-quark production, and propose a scheme to match the relevant samples
to the next-to-leading-order predictions.Comment: 40 pgs., revtex4, 35 ps figs; added Fig. 4, 1 Ref., minor
clarifications, to appear in Phys. Rev.
Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234
We present the analysis of a total of 177h of high-quality optical
time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC
20058-5234. The bulk of the observations (135h) were obtained during a WET
campaign (XCOV15) in July 1997 that featured coordinated observing from 4
southern observatory sites over an 8-day period. The remaining data (42h) were
obtained in June 2004 at Mt John Observatory in NZ over a one-week observing
period. This work significantly extends the discovery observations of this
low-amplitude (few percent) pulsator by increasing the number of detected
frequencies from 8 to 18, and employs a simulation procedure to confirm the
reality of these frequencies to a high level of significance (1 in 1000). The
nature of the observed pulsation spectrum precludes identification of unique
pulsation mode properties using any clearly discernable trends. However, we
have used a global modelling procedure employing genetic algorithm techniques
to identify the n, l values of 8 pulsation modes, and thereby obtain
asteroseismic measurements of several model parameters, including the stellar
mass (0.55 M_sun) and T_eff (~28200 K). These values are consistent with those
derived from published spectral fitting: T_eff ~ 28400 K and log g ~ 7.86. We
also present persuasive evidence from apparent rotational mode splitting for
two of the modes that indicates this compact object is a relatively rapid
rotator with a period of 2h. In direct analogy with the corresponding
properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude
pulsation behaviour of EC 20058 is entirely consistent with its inferred
effective temperature, which indicates it is close to the blue edge of the DBV
instability strip. (abridged)Comment: 19 pages, 8 figures, 5 tables, MNRAS accepte
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