Zonal analysis of two high-speed inlets

Using a zonal technique, thin layer Navier-Stokes solutions for two high speed inlet geometries are presented and compared with experimental data. The first configuration consists of a 3-D inlet preceded by a sharp flat plate. Results with two different grids demonstrate the importance of adequate grid refinement in high speed internal flow computations. The fine grid solution has reasonably good agreement with experimental heat transfer and pressure values inside the inlet. The other configuration consists of a 3-D inlet mounted on a research hypersonic forebody. Numerical results for this configuration have good agreement with experimental pressure data along the forebody, but not inside the inlet. A more refined grid calculation is currently being done to better predict the flowfield in the inlet

On the Factor Refinement Principle and its Implementation on Multicore Architectures

The factor refinement principle turns a partial factorization of integers (or polynomi­ als) into a more complete factorization represented by basis elements and exponents, with basis elements that are pairwise coprime. There are lots of applications of this refinement technique such as simplifying systems of polynomial inequations and, more generally, speeding up certain algebraic algorithms by eliminating redundant expressions that may occur during intermediate computations. Successive GCD computations and divisions are used to accomplish this task until all the basis elements are pairwise coprime. Moreover, square-free factorization (which is the first step of many factorization algorithms) is used to remove the repeated patterns from each input element. Differentiation, division and GCD calculation op­ erations are required to complete this pre-processing step. Both factor refinement and square-free factorization often rely on plain (quadratic) algorithms for multipli­ cation but can be substantially improved with asymptotically fast multiplication on sufficiently large input. In this work, we review the working principles and complexity estimates of the factor refinement, in case of plain arithmetic, as well as asymptotically fast arithmetic. Following this review process, we design, analyze and implement parallel adaptations of these factor refinement algorithms. We consider several algorithm optimization techniques such as data locality analysis, balancing subproblems, etc. to fully exploit modern multicore architectures. The Cilk++ implementation of our parallel algorithm based on the augment refinement principle of Bach, Driscoll and Shallit achieves linear speedup for input data of sufficiently large size

The Study of Cotton Extraction by Using Microwave Assisted

This work aimed to learn the effect of concentration, temperature, and time of extraction toward physical appearances and also changes in lattice parameters. The failed extraction was exhibited by black, transparent, and undissolved cotton. Meanwhile, successful products were indicated by the white suspension. This research was carried out by using the microwave-assisted machine to extract the cotton. The optimum conditions were reached at 55% acid concentration, 30°C reaction temperature, varied time reaction from 1 to 15 minutes. The refinement by using Rietica’s software and Le Bail’s method showed that the extraction product in a monoclinic crystal structure. It was found the compatibility between experimental data and calculation results. The refinement references were a = 0.82 nm, b = 1.03 nm, c = 0.78 nm, α = γ = 90 º and β = 84. Lattice parameter after hydrolysis was greatly different with cotton, mainly in a

Strategic term rewriting and its application to a VDM-SL to SQL conversion

We constructed a tool, called VooDooM, which converts datatypes in Vdm-sl into Sql relational data models. The conversion involves transformation of algebraic types to maps and products, and pointer introduction. The conversion is specified as a theory of refinement by calculation. The implementation technology is strategic term rewriting in Haskell, as supported by the Strafunski bundle. Due to these choices of theory and technology, the road from theory to practise is straightforward.Fundação para a Ciência e a Tecnologia (FCT) - POSI/ICHS/44304/2002Agência de Inovação (ADI) - ∑!223

Computational protein crystallography : How to get the most out of your data

It is important to obtain accurate three dimensional structures of molecules and proteins to understand and predict their function and behaviour. X-ray crystallography is the major technique to determine three dimensional structures of proteins. Although there have been major improvements on the experimental side in determining crystallographic data, only small progress has been made on the computational side to get a correct model andinterpretation of this data.In small-molecule crystallography, some of the shortcomings in the model have already been overcome, but in protein crystallography they still remain. Therefore, we have adapted the Hirshfeld atom refinement from small-molecule crystallography to make it available also to protein crystallography. This enables improved modelling of high-resolution protein data. To achieve this goal, we combined the molecular fractionation with conjugate caps approach with the Hirshfeld atom refinement. We call this combined method fragHAR. With fragHAR, we could perform the first Hirshfeld atom refinement of a metalloprotein.Furthermore, we improved and applied the quantum refinement method, which employs quantum mechanics calculations to obtain a chemically and physically correct model for all parts of the protein, especially the active site. With quantum refinement, it is possible to distinguish between different interpretations of the structure, e.g. the elemental composition or the protonation state, even from medium-resolution crystallographic data. In this thesis, quantum refinement was improved for highly-charged systems by applying a continuum-solvent description of the surroundings in the quantum mechanics calculation. Furthermore, quantum refinement was applied to settle the nature of the unusual bidentate ligand in V-nitrogenase and the protonation state of the MoFe cluster in Mo-nitrogenase when inhibited by CO. For a recent structure of Mo-nitrogenase, we showed that there is no experimental support for the suggestion that N 2 is bound to the MoFe-cluster and presented a more likely model. We have also identified the most probable protonation states of the active site in acetylcholinesterase before and after inhibition by nerve agents. Finally, for triosephosphate isomerase we used a joint X-ray and neutron quantum refinement to investigate the hydrogen bond between an inhibitor and Lys-13

Equation of State for laboratory astrophysics applications

New improvements on the calculation of Equation of State (EOS) for laboratory astrophysics applications are presented. A new empirical multiplier for the EOS is included to the original quotidian equation of state (QEOS) model developed by More et al. (Phys. Fluids 31:3059, 1988) to adapt it to the available experimental data and ab initio molecular dynamics simulation. This model is used to obtain EOS tables suited for an adaptive mesh refinement hydrodynamic code with radiation transport for high energy density plasmas simulations called ARWEN introduced by Ogando and Velarde (J. Quant. Spectrosc. Radiat. Transf. 71(2–6):541, 2001)

Hydra: A Parallel Adaptive Grid Code

We describe the first parallel implementation of an adaptive particle-particle, particle-mesh code with smoothed particle hydrodynamics. Parallelisation of the serial code, ``Hydra'', is achieved by using CRAFT, a Cray proprietary language which allows rapid implementation of a serial code on a parallel machine by allowing global addressing of distributed memory. The collisionless variant of the code has already completed several 16.8 million particle cosmological simulations on a 128 processor Cray T3D whilst the full hydrodynamic code has completed several 4.2 million particle combined gas and dark matter runs. The efficiency of the code now allows parameter-space explorations to be performed routinely using $64^3$ particles of each species. A complete run including gas cooling, from high redshift to the present epoch requires approximately 10 hours on 64 processors. In this paper we present implementation details and results of the performance and scalability of the CRAFT version of Hydra under varying degrees of particle clustering.Comment: 23 pages, LaTex plus encapsulated figure

ColDICE: a parallel Vlasov-Poisson solver using moving adaptive simplicial tessellation

Resolving numerically Vlasov-Poisson equations for initially cold systems can be reduced to following the evolution of a three-dimensional sheet evolving in six-dimensional phase-space. We describe a public parallel numerical algorithm consisting in representing the phase-space sheet with a conforming, self-adaptive simplicial tessellation of which the vertices follow the Lagrangian equations of motion. The algorithm is implemented both in six- and four-dimensional phase-space. Refinement of the tessellation mesh is performed using the bisection method and a local representation of the phase-space sheet at second order relying on additional tracers created when needed at runtime. In order to preserve in the best way the Hamiltonian nature of the system, refinement is anisotropic and constrained by measurements of local Poincar\'e invariants. Resolution of Poisson equation is performed using the fast Fourier method on a regular rectangular grid, similarly to particle in cells codes. To compute the density projected onto this grid, the intersection of the tessellation and the grid is calculated using the method of Franklin and Kankanhalli (1993) generalised to linear order. As preliminary tests of the code, we study in four dimensional phase-space the evolution of an initially small patch in a chaotic potential and the cosmological collapse of a fluctuation composed of two sinusoidal waves. We also perform a "warm" dark matter simulation in six-dimensional phase-space that we use to check the parallel scaling of the code.Comment: Code and illustration movies available at: http://www.vlasix.org/index.php?n=Main.ColDICE - Article submitted to Journal of Computational Physic