ViscoSolve: Porting, Optimization and Performance Analysis of Viscoelastic Fluid Flow Code

ViscoSolve is a stable unstructured finite volume method for parallel large-scale viscoelastic fluid flow calculations. The code incorporates the open-source libraries PETSc and MPI for parallel computation. In this whitepaper we report work that was done to investigate scaling the performance of the ViscoSolve code

Simulation of granular soil behaviour using the bullet physics library

A physics engine is computer software which provides a simulation of certain physical systems, such as rigid body dynamics, soft body dynamics and fluid dynamics. Physics engines were firstly developed for using in animation and gaming industry ; nevertheless, due to fast calculation speed they are attracting more and more attetion from researchers of the engineering fields. Since physics engines are capable of performing fast calculations on multibody rigid dynamic systems, soil particles can be modeled as distinct rigid bodies. However, up to date, it is not clear to what extent they perform accurately in modeling soil behaviour from a geotechnical viewpoint. To investigate this, examples of pluviation and vibration-induced desification were simulated using the physics engine called Bullet physics library. In order to create soil samples, first, randomly shaped polyhedrons, representing gravels, were generated using the Voronoi tessellation approach. Then, particles were pluviated through a funnel into a cylinder. Once the soil particles settled in a static state, the cylinder was subjected to horizontal sinusoidal vibration for a period of 20 seconds. The same procedure for sample perparation was performed in the laboratory. The results of pluviation and vibration tests weere recorded and compared to those of simulations. A good agreement has been found between the results of simulations and laboratory tests. The findings in this study reinforce the idea that physics engines can be employed as a geotechnical engineering simulation tool

Assessment of genotype x environment interaction on yield and yield components of durum wheat genotypes by multivariate analyses

Wheat breeders have to determine the new cultivars and lines responsive to the environmental changes for grain yield and yield components. Therefore, this study was conducted to evaluate 25 durum wheat (Triticum turgidum spp. durum) genotypes including 12 registered cultivars and 13 advanced breeding lines for their stability grown in three different locations (Tokat-Kazova, Diyarbakir and Sivas-Ulas) of Turkey for two growing seasons (2005-2006 and 2006-2007), and to select genotypes having desirable traits to be used in future durum wheat breeding program. Field trials were conducted in a randomized complete block design with three replications at each location. Days to heading, plant height, number of spikes per square meter, number of kernels per spike, spike weight, 1000 kernel weight and grain yield of the genotypes were evaluated in each location. The regression coefficient (bi) of Finlay and Wilkinson (1963) and mean square of deviation from regression (S2d) of Eberhart and Russell (1966) were used as the stability parameters. The results of combined analysis of variance showed a strong influence of the locations on plant height, number of spikes per square meter, number of kernels per spike,  spike weight, 1000 kernel weight and grain yield. Genotypic effects were mainly observed for spike length and test weight. Year had strong impact only on the days to heading. Ecological conditions of Diyarbakir among locations offer the better opportunity for production of durum wheat. Line 5 and cultivar Gidara were both stable in yield ability and also appeared the stable group based on the cluster analysis. In the first principal component days to heading, number of spikes per square meter and spike length  were the most important traits contributing to variation that obtained about 44.3%. There was a positive relationship between grain yield and number of spikes per square meter together test weight, whereas days to heading and spike length were negatively correlated to grain yield. The results of this study also imply that Line-5 and cultivar Gidara among genotypes were the most stable cultivars and can be used as breeding materials. The days to heading, number of spikes per square meter and spike length could be adequate to introduce the differences among genotypes.Key words: Durum wheat, stability, principal component analysis, cluster analysis

Characterization of platinum nitride from first-principles calculations

We have performed a systematic study of the ground state properties of the zinc-blende, rock-salt, tetragonal, cuprite, fluorite and pyrite phases of platinum nitride by using the plane wave pseudopotential calculations within the density functional theory. The equilibrium structural parameters and bulk moduli are computed within both the local density approximation (LDA) and generalized gradient approximation (GGA). The comparison of the equation of state (EOS) calculated within the LDA for the pyrite structure with the experimental results demonstrates an excellent agreement, hence the use of the LDA rather than the GGA is essential. Complete sets of elastic moduli are presented for cubic forms. The analysis of the results reveal that the pyrite phase with PtN2 stoichiometry leads to the formation of a hard material with the shear modulus G = 206GPa. The electronic structure of pyrite PtN2 is given, which shows a narrow indirect gap. The vibrational properties of platinum nitride are investigated in detail from lattice dynamical calculations. The calculations show that fluorite and pyrite structures are dynamically stable as well. However, the calculated vibrational modes of pyrite PtN2 do not show complete agreement with experimental Raman frequencies. © 2009 IOP Publishing Ltd

Products and Process Modeling in Cx: A Significant Challenge for Digital-Cx

In the next decade, digitalization of commissioning (Cx) is likely to be a key advance, in the field of AEC. This requires that as much of what we do manually, through word processing and spreadsheets can be done through sophisticated computer applications to enhance Cx productivity. The first step in achieving this is the creation of reliable, persistent, accurate, just-in-time, and easily accessible Cx information. Towards this end we are building a proof-of-concept prototype for functional performance tests (FPT) that can help Cx agents derive product models through specifying process descriptions

Ontology Development for Low-Energy Building Embedded Commissioning

This paper presents the results of initial work in developing an ontology for improving information exchange and automation in building system commissioning practices. In our previous research dealing with the derivation of product models from building commissioning process models, we found that there is a need to categorize and classify information items, which are available in commissioning process descriptions. In addition, the relationship between these items should be clearly defined to establish a topological relationship between items necessary for specifying product models. Ontology development is the way to categorize and classify domain knowledge information and items into inter-related concepts. Ontology assembles information in the form of concept hierarchies (taxonomies), axioms, and semantic relationships, which allow natural language to be presented unambiguously. A glossary (a lower form of ontology) specific to building commissioning tasks was developed as a first step. In the second step, an ontology for use in commissioning software applications was developed

Stationary State Solutions of a Bond Diluted Kinetic Ising Model: An Effective-Field Theory Analysis

We have examined the stationary state solutions of a bond diluted kinetic Ising model under a time dependent oscillating magnetic field within the effective-field theory (EFT) for a honeycomb lattice $(q=3)$. Time evolution of the system has been modeled with a formalism of master equation. The effects of the bond dilution, as well as the frequency $(\omega)$ and amplitude $(h/J)$ of the external field on the dynamic phase diagrams have been discussed in detail. We have found that the system exhibits the first order phase transition with a dynamic tricritical point (DTCP) at low temperature and high amplitude regions, in contrast to the previously published results for the pure case \cite{Ling}. Bond dilution process on the kinetic Ising model gives rise to a number of interesting and unusual phenomena such as reentrant phenomena and has a tendency to destruct the first-order transitions and the DTCP. Moreover, we have investigated the variation of the bond percolation threshold as functions of the amplitude and frequency of the oscillating field.Comment: 8 pages, 4 figure

Embedded Commissioning for Building Design

Building Commissioning has a broad scope that extends to all phases of building delivery. We view commissioning as a building delivery embedded process that persistently verifies and validates design intent throughout the building lifecycle process. In the building lifecycle approach, buildings are considered to have cradle-to-grave life spans. They are modeled through a variety of different developmental phases. In this research project, we intend to build the necessary theory and tools to support the embedded commissioning process as a co-function of building lifecycle