67 research outputs found
On the log-local principle for the toric boundary
Let be a smooth projective complex variety and let be
a reduced normal crossing divisor on with each component smooth,
irreducible, and nef. The log-local principle of van Garrel-Graber-Ruddat
conjectures that the genus 0 log Gromov-Witten theory of maximal tangency of
is equivalent to the genus 0 local Gromov-Witten theory of twisted
by . We prove that an extension of the
log-local principle holds for a (not necessarily smooth)
-factorial projective toric variety, the toric boundary, and
descendent point insertions.Comment: 19 page
Development of Free Vortex Wake Method for Yaw Misalignment Effect on the Thrust Vector and Generated Power
Wind power is currently one of the most reliable new energy sources serving as an alternative to fossil fuel generated electricity and is known as a widely distributed clean and renewable source of energy. It is now the world's fastest growing energy source and has also become one of the most rapidly expanding industries. The aerodynamics of a wind turbine is governed by the flow around the rotor, where the prediction of air loads on rotor blades in different operational conditions and their relation to rotor structural dynamics is crucial for design purposes. One of the challenges in wind turbine aerodynamics is the yaw condition where the undisturbed upstream flow is not perpendicular to the rotor plane, giving a non-uniform blade load which is contrary to the axisymmetric flow assumption in the BEM (Blade Element Momentum) method. However, there are some engineering methods modifying the BEMmethod for yaw misalignment situations,1 where they often calculate the skewed axial induction factor as an average value over the rotor disk which is insensitive to the blade rotation direction. On the other hand, experiments show that the thrust vector for a positive yaw misalignment differs from that for a negative yaw misalignment. A free vortex wake method, based on the potential, inviscid and irrotational flow, is developed to study the deviation of thrust vector relative to rotor shaft. The results are compared with the BEM method2 and experimental data. A two-bladed variable speed wind turbine, the Hönö wind turbine,3 is used for this study
Gemini multi-conjugate adaptive optics system review II: Commissioning, operation and overall performance
The Gemini Multi-conjugate Adaptive Optics System - GeMS, a facility
instrument mounted on the Gemini South telescope, delivers a uniform, near
diffraction limited images at near infrared wavelengths (0.95 microns- 2.5
microns) over a field of view of 120 arc seconds. GeMS is the first sodium
layer based multi laser guide star adaptive optics system used in astronomy. It
uses five laser guide stars distributed on a 60 arc seconds square
constellation to measure for atmospheric distortions and two deformable mirrors
to compensate for it. In this paper, the second devoted to describe the GeMS
project, we present the commissioning, overall performance and operational
scheme of GeMS. Performance of each sub-system is derived from the
commissioning results. The typical image quality, expressed in full with half
maximum, Strehl ratios and variations over the field delivered by the system
are then described. A discussion of the main contributor to performance
limitation is carried-out. Finally, overheads and future system upgrades are
described.Comment: 20 pages, 11 figures, accepted for publication in MNRA
An infusion of new blood using the Toptica laser with GeMS: Results of the commissioning and science performance
Adaptive Optics (AO) systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences. The Gemini Multi Conjugated AO System GeMS is operational and regularly used for science observations since 2013 delivering close to diffraction limit resolution over a large field of view. GeMS entered this year into a new era. The laser system has been upgraded from the old 50W Lockheed Martin Coherent Technologies (LMCT) pulsed laser to the Toptica 20/2W CW SodiumStar laser. The laser has been successfully commissioned and is now used regularly in operation. In this paper we first review the performance obtained with the instrument. I will go then into the details of the commissioning of the Toptica laser and show the improvements obtained in term of acquisition, stability, reliability and performanc
Glutamine supplementation
Intravenous glutamine supplementation is standard care when parenteral nutrition is given for critical illness. There are data of a reduced mortality when glutamine supplementation is given. In addition, standard commercial products for parenteral nutrition do not contain any glutamine due to glutamine instability in aqueous solutions. For the majority of critical ill patients who are fed enterally, the available evidence is insufficient to recommend glutamine supplementation. Standard formulation of enteral nutrition contains some glutamine: 2-4 g/L. However, this dose is insufficient to normalize glutamine plasma concentration
Unsteady Interacting Boundary Layer Method
Within this study an unsteady, two-dimensional interacting boundary layer method is presented for the incompressible flow around wind turbine rotor blade sections. The main approach is to divide the flow field in to two regions; the one in the vicinity of the surface where the viscosity is effective (so called boundary layer) and the one away from the surface where the flow can be assumed as inviscid. The solutions obtained from these two regions are matched with a quasi-simultaneous viscous-inviscid interaction scheme. For the viscous flow, unsteady integral boundary layer equations together with laminar and turbulent closure sets are solved employing a high-order quadrature-free discontinuous Galerkin method. Laminar to turbulent transition is modeled with the eNmethod. The potential flow is solved by using the linear-strength vortex panel method. It is shown that introducing the interaction scheme leads to non-conservative mechanisms in the system. The discontinuous Galerkin method is extended to handle these non-conservative flux terms. Furthermore it is shown that this numerical method achieves the designed order of accuracy for smooth problems. Results are presented for the individual numerical solution methods which are verified on various test cases and subsequently for the coupled system which is applied on a chosen test case. Evaluation of a laminar flow over an airfoil section is shown and the results (converged to a steady state solution) are compared with other numerical solutions as well as with the experimental data where available. It is shown that the results of the developed numerical solution method are in good agreement with the experimental data and other computational methods
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