4,273 research outputs found
Feasibility of observer system for determining orientation of balloon borne observational platforms
An observer model for predicting the orientation of balloon borne research platforms was developed. The model was employed in conjunction with data from the LACATE mission in order to determine the platform orientation as a function of time
Student Perceptions and Learning Outcomes: Evidence from the Education Testing Service (ETS) Major Field Test in Business
We examine course evaluation data from the core finance course and analyze how these data relate to performance on the finance portion of the Educational Testing Service Major Field Test in Business (ETS). We find that gender, SAT scores, GPA and concentration all have significant impacts on student performance. We also find that student perceptions of teaching and of how much knowledge they gained do not relate to the finance ETS score. Finally, we find that students who feel challenged in their finance core course do significantly better on the finance portion of the exam. This result is robust to different data partitions
Intermediate Debonding in Frp Strengthened RC Beams: a Numerical Model
One of the most effective ways for improving the flexural strength of RC members consists in bonding FRP laminates at their soffit in order to upgrade the existing tensile strength. Strengthening RC beams by Externally Bonded FRP laminates is getting more and more common and various Codes of Standards have been issued in Europe, United States and Japan. In particular, the most up-to-date document has been released in Italy one year ago. A key problem to be faced when managing FRP strengthened beams deals with the possible premature failure due to debonding between the adhesive layer and concrete, which can occur at the beam end (end debonding) or in the cracked zone (intermediate debonding). In the present paper, a mechanical model considering non-linear stress-strain relationships for concrete, steel and FRP-to-concrete interface is presented, with the aim of simulating the behavior of RC beams strengthened by externally bonded FRP plates
Perceptions of Reading Instruction
It follows that there exists an obvious need for elementary reading programs to be closely articulated with the developing and changing reading requirements of pupils as they progress through the elementary grades. There is an even more obvious need for close cooperation between teachers and administrators in order to implement reading programs that meet pupil requirements
Study of a Pump-as-Turbine (PaT) speed control for a Water Distribution Network (WDN) in South-Tyrol subjected to high variable water flow rates
Abstract The development of renewable energy technologies for producing clean energy has more and more become a priority worldwide. Research activities have not just to target the technological improvement of such systems, but they have also to consider their market deployment. In such a scenario, hydraulic machines, in particular Pumps-as-Turbines (PaTs), can play a key role in energy recovery applications. One of the main open issues of PaTs is the performance forecast in turbine mode, due to the lack of data from manufacturers, and their use in some applications with high flow rate and pressure variability, especially at part-load operating conditions like in energy recovery applications within Water Distribution Networks (WDNs). In this work, a MATLAB® Simulink model is developed for simulating a branch of the WDN located in Laives (South-Tyrol), where specific PaTs have been selected and used to substitute Pressure Reducing Valves (PRVs). A speed control by means of an inverter is performed due to the high variability of the flow rate inside the grid branch, allowing the machines to operate at their Best Efficiency Point (BEP). A preliminary analysis showed that it is possible to increase the energy production of about 23% with respect to a constant-speed machine, leading to a significant decrease of the PayBack Period (PBP)
High-order Discontinuous Galerkin Solutions of Internal Low-mach Number Turbulent Flows☆
Abstract In this work we apply the high-order Discontinuous Galerkin (DG) finite element method to internal low-Mach number turbulent flows. The method here presented is designed to improve the performance of the solution in the incompressible limit using an implicit scheme for the temporal integration of the compressible Reynolds Averaged Navier Stokes (RANS) equations. The per- formance of the scheme is demonstrated by solving a well-known test-case consisting of an abrupt axisymmetric expansion using various degrees of polynomial approximation. Computations with k–ω model are performed to assess the modelling capabilities, with high-order accurate DG discretizations of the RANS equations, in presence of non-equilibrium flow conditions
Depletion-interaction effects on the tunneling conductivity of nanorod suspensions
We study by simulation and theory how the addition of insulating spherical particles affects the conductivity of fluids of conducting rods, modeled by spherocylinders. The electrical connections are implemented as tunneling processes, leading to a more detailed and realistic description than a discontinuous percolation approach. We find that the spheres enhance the tunneling conductivity for a given concentration of rods and that the enhancement increases with rod concentration into the regime where the conducting network is well established. By reformulating the network of rods using a critical path analysis, we quantify the effect of depletion-induced attraction between the rods due to the spheres. Furthermore, we show that our conductivity data are quantitatively reproduced by an effective-medium approximation, which explicitly relates the system tunneling conductance to the structure of the rod-sphere fluid
On the Integrable Structure of the Ising Model
Starting from the lattice realization of the Ising model defined on a
strip with integrable boundary conditions, the exact spectrum (including
excited states) of all the local integrals of motion is derived in the
continuum limit by means of TBA techniques. It is also possible to follow the
massive flow of this spectrum between the UV conformal fixed point and
the massive IR theory. The UV expression of the eigenstates of such integrals
of motion in terms of Virasoro modes is found to have only rational
coefficients and their fermionic representation turns out to be simply related
to the quantum numbers describing the spectrum.Comment: 18 pages, no figure
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