1,060 research outputs found
Ultrasonic quality inspection of bonded honeycomb assemblies is automated
Inspection system for bonded honeycomb assemblies is accurate, fast, and automated. The ultrasonic system consists of inner and outer transducer positioning assemblies with suitable motor controls, a centerless turntable assembly, water squirter assemblies, and an inspection program completely encoded on tape suitable for use on a high speed computer
SOCIOEMOTIONAL FUNCTIONING AS A MODERATOR OF THE PREDICTIVE ABILITY OF THE DIAL-4 ON ACADEMIC ACHIEVEMENT
Student performance on kindergarten screening measures and level of kindergarten-entry skills have been shown to be predictive of subsequent academic achievement, thus making kindergarten screening measures a useful tool that guides the monitoring of student progress over time. Though a commonly used tool to assist in kindergarten placement considerations by educators nationwide, the literature is lacking in studies that demonstrate the predictive ability of the Developmental Indicators for the Assessment of Learning â Fourth Edition (DIAL-4) on later academic achievement. Related, behavioral and emotional functioning has been demonstrated to significantly impact student achievement. While the literature supports the predictive ability of kindergarten screening measures on academic performance, research is limited on how behavioral functioning moderates this predictive relationship. The present study aimed to examine the predictive ability of the DIAL-4 on later academic achievement and identify whether behavioral and emotional functioning impacts upon, and to what degree, the relationship between academic achievement and the DIAL-4. Additionally, this study examined the impact of the pause of in-person learning, as caused by the COVID-19 pandemic on student achievement and behavioral and emotional functioning through within-samples comparisons of student functioning in 2019 and 2021 to identify change amongst individual students. The results support the predictive ability of the DIAL-4 on subsequent academic achievement with significant correlations between DIAL-4 scores obtained before kindergarten with subsequent measures of academic achievement. The was no evidence found for a moderation effect of behavioral and emotional functioning on the prediction of academic achievement. Lastly, when controlling for scores on the DIAL-4, the data suggest a decrease in rate of student academic achievement and an increase in emotional and behavioral dysregulation following the onset of the COVID-19 pandemic demonstrated by statistically significant differences in BERI scores as well as significant decreases in rates of growth in reading ability within some cohorts. These findings provide educators with empirical evidence for the utility of the DIAL-4 in predicting academic achievement as well as insight into how the COVID-19 pandemic impacted studentsâ functioning
Reliability Centered Maintenance - Methodologies
Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies
Wigner measures and codimension two crossings
This article gives a semiclassical description of nucleonic propagation through codimension two crossings of electronic energy levels. Codimension two crossings are the simplest energy level crossings, which affect the BornâOppenheimer approximation in the zeroth order term. The model we study is a two-level Schrödinger equation with a Laplacian as kinetic operator and a matrix-valued linear potential, whose eigenvalues cross, if the two nucleonic coordinates equal zero. We discuss the case of well-localized initial data and obtain a description of the wavefunctionâs two-scaled Wigner measure and of the weak limit of its position density, which is valid globally in time
Single switch surface hopping for molecular dynamics with transitions
A trajectory surface hopping algorithm is proposed, which stems from a mathematically rigorous analysis of propagation through conical intersections of potential energy surfaces. Since nonadiabatic transitions are only performed when a classical trajectory attains one of its local minimal surface gaps, the algorithm is called single switch surface hopping. Numerical experiments for a two mode JahnâTeller system are presented, which illustrate the asymptotic justification of the method as well as its good performance in the physically relevant parameter range
Propagation through Generic Level Crossings: A Surface Hopping Semigroup
We construct a surface hopping semigroup, which asymptotically describes nuclear propagation through crossings of electron energy levels. The underlying time-dependent Schrödinger equation has a matrix-valued potential, whose eigenvalue surfaces have a generic intersection of codimension two, three, or five in Hagedorn's classification. Using microlocal normal forms reminiscent of the LandauâZener problem, we prove convergence to the true solution with an error of the order , where is the semiclassical parameter. We present numerical experiments for an algorithmic realization of the semigroup illustrating the convergence of the algorithm
Cluster-resolved dynamic scaling theory and universal corrections for transport on percolating systems
For percolating systems, we propose a universal exponent relation connecting
the leading corrections to scaling of the cluster size distribution with the
dynamic corrections to the asymptotic transport behaviour at criticality. Our
derivation is based on a cluster-resolved scaling theory unifying the scaling
of both the cluster size distribution and the dynamics of a random walker. We
corroborate our theoretical approach by extensive simulations for a site
percolating square lattice and numerically determine both the static and
dynamic correction exponents.Comment: 6 pages, 5 figures, 1 tabl
Unconventional motional narrowing in the optical spectrum of a semiconductor quantum dot
Motional narrowing refers to the striking phenomenon where the resonance line
of a system coupled to a reservoir becomes narrower when increasing the
reservoir fluctuation. A textbook example is found in nuclear magnetic
resonance, where the fluctuating local magnetic fields created by randomly
oriented nuclear spins are averaged when the motion of the nuclei is thermally
activated. The existence of a motional narrowing effect in the optical response
of semiconductor quantum dots remains so far unexplored. This effect may be
important in this instance since the decoherence dynamics is a central issue
for the implementation of quantum information processing based on quantum dots.
Here we report on the experimental evidence of motional narrowing in the
optical spectrum of a semiconductor quantum dot broadened by the spectral
diffusion phenomenon. Surprisingly, motional narrowing is achieved when
decreasing incident power or temperature, in contrast with the standard
phenomenology observed for nuclear magnetic resonance
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