14,480 research outputs found
The Literary Coach as Instructional Leader: How Three Literacy Coaches in Rural Georgia Improve Teacher Practices
Author\u27s abstract: The bar has been raised on student achievement in the United States and on teaching quality as well. Compelling evidence confirms that a teacher\u27s mastery of the academic content of what he or she teaches is critical to engaging students and inspiring them to academic excellence (Addey, 2000; Wilkinson, 2002). In order to truly impact instructional effectiveness, transformations must occur on the frontlines as teachers put research based theories into practice. A major obstacle facing literacy coaches and leadership teams is identifying an effective implementation model and practice that promotes and support high quality literacy instruction through direct, school-based work with teachers in a district. To understand the support of various models, the researcher will examine the experiences of exemplary literacy coaches as evidenced by test scores and coaches who have been named as Coach of the Year by the school district. Therefore, the purpose of this study is to understand the effective practices of exemplary literacy coaches as instructional leaders and the models and strategies being implemented that support teacher development
Evolutionary L∞ identification and model reduction for robust control
An evolutionary approach for modern robust control oriented system identification and model reduction in the frequency domain is proposed. The technique provides both an optimized nominal model and a 'worst-case' additive or multiplicative uncertainty bounding function which is compatible with robust control design methodologies. In addition, the evolutionary approach is applicable to both continuous- and discrete-time systems without the need for linear parametrization or a confined problem domain for deterministic convex optimization. The proposed method is validated against a laboratory multiple-input multiple-output (MIMO) test rig and benchmark problems, which show a higher fitting accuracy and provides a tighter L�¢���� error bound than existing methods in the literature do
Magnetic Reconnection resulting from Flux Emergence: Implications for Jet Formation in the lower solar atmosphere?
We aim at investigating the formation of jet-like features in the lower solar
atmosphere, e.g. chromosphere and transition region, as a result of magnetic
reconnection. Magnetic reconnection as occurring at chromospheric and
transition regions densities and triggered by magnetic flux emergence is
studied using a 2.5D MHD code. The initial atmosphere is static and isothermal,
with a temperature of 20,000 K. The initial magnetic field is uniform and
vertical. Two physical environments with different magnetic field strength (25
G and 50 G) are presented. In each case, two sub-cases are discussed, where the
environments have different initial mass density. In the case where we have a
weaker magnetic field (25 G) and higher plasma density (
cm), valid for the typical quiet Sun chromosphere, a plasma jet would be
observed with a temperature of 2--3 K and a velocity as high as
40 km/s. The opposite case of a medium with a lower electron density
( cm), i.e. more typical for the transition region,
and a stronger magnetic field of 50 G, up-flows with line-of-sight velocities
as high as 90 km/s and temperatures of 6 10 K, i.e. upper
transition region -- low coronal temperatures, are produced. Only in the latter
case, the low corona Fe IX 171 \AA\ shows a response in the jet which is
comparable to the O V increase. The results show that magnetic reconnection can
be an efficient mechanism to drive plasma outflows in the chromosphere and
transition region. The model can reproduce characteristics, such as temperature
and velocity for a range of jet features like a fibril, a spicule, an hot X-ray
jet or a transition region jet by changing either the magnetic field strength
or the electron density, i.e. where in the atmosphere the reconnection occurs.Comment: 11 pages, 13 figures, 2 table
Assessment of the visibility impairment caused by the emissions from the proposed power plant at Boron, California
The current atmospheric conditions and visibility were modeled, and the effect of the power plant effluent was then added to determine its influence upon the prevailing visibility; the actual reduction in visibility being a function of meteorological conditions and observer-plume-target geometry. In the cases investigated, the perceptibility of a target was reduced by a minimum of 10 percent and a maximum of 100 percent. This significant visual impact would occur 40 days per year in the Edwards area with meteorological conditions such as to cause some visual impact 80 days per year
High-order volterra model predictive control and its application to a nonlinear polymerisation process
Model Predictive Control (MPC) has recently found wide acceptance in the process industry, but the existing design and implementation methods are restricted to linear process models. A chemical process involves, however, severe nonlinearity which cannot be ignored in practice. This paper aims to solve this nonlinear control problem by extending MPC to nonlinear models. It develops an analytical framework for nonlinear model predictive control (NMPC), and also offers a third-order Volterra series based nonparametric nonlinear modelling technique for NMPC design which relieves practising engineers from the need for first deriving a physical-principles based model. An on-line realisation technique for implementing the NMPC is also developed. The NMPC is then applied to a Mitsubishi Chemicals polymerisation reaction process. The results show that this nonlinear MPC technique is feasible and very effective. It considerably outperforms linear and low-order Volterra model based methods. The advantages of the approach developed lie not only in control performance superior to existing NMPC methods, but also in relieving practising engineers from the need for deriving an analytical model and then converting it to a Volterra model through which the model can only be obtained up to the second order
Influence of low-level Pr substitution on the superconducting properties of YBa2Cu3O7-delta single crystals
We report on measurements on Y1-xPrxBa2Cu3O7-delta single crystals, with x
varying from 0 to 2.4%. The upper and the lower critical fields, Hc2 and Hc1,
the Ginzburg-Landau parameter and the critical current density, Jc(B), were
determined from magnetization measurements and the effective media approach
scaling method. We present the influence of Pr substitution on the pinning
force density as well as on the trapped field profiles analyzed by Hall probe
scanning.Comment: 4 pages, 5 figures, accepted for publication in J. Phys. Conf. Se
- …