A New Algorithm for Generating Highly Accurate Benchmark Solutions to Transport Test Problems

We present a new algorithm for solving the neutron transport equation in its discrete-variable form. The new algorithm is based on computing the full matrix relating the scalar flux spatial moments in all cells to the fixed neutron source spatial moments, foregoing the need to compute the angular flux spatial moments, and thereby eliminating the need for sweeping the spatial mesh in each discrete-angular direction. The matrix equation is solved exactly in test cases, producing a solution vector that is free from iteration convergence error, and subject only to truncation and roundoff errors. Our algorithm is designed to provide method developers with a quick and simple solution scheme to test their new methods on difficult test problems without the need to develop sophisticated solution, e.g. acceleration, algorithms before establishing the worthiness of their innovation. We demonstrate the utility of the new algorithm by applying it to the Arbitrarily High Order Transport Nodal (AHOT-N) method, and using it to solve Burre`s Test Problem, a suite of benchmark problems that covers a large region in parameter space. Our results provide highly accurate benchmark solutions, that can be distributed electronically and used to verify the pointwise accuracy of other solution methods and algorithms

A ROBUST ARBITRARILY HIGH ORDER TRANSPORT METHOD OF THE CHARACTERISTIC TYPE FOR UNSTRUCTURED TETRAHEDRAL GRIDS

We present a robust arbitrarily high order transport method of the characteristic type for unstructured tetrahedral grids. Previously encountered difficulties have been addressed through the reformulation of the method based on coordinate transformations, evaluation of the moments balance relation as a linear system of equations involving the expansion coefficients of the projected basis, and the asymptotic expansion of the integral kernels in the thin cell limit. The proper choice of basis functions for the high-order spatial expansion of the solution is discussed and its effect on problems involving scattering discussed. Numerical tests are presented to illustrate the beneficial effect of these improvements, and the improved robustness they yield

Pengaruh Harga Tembakau Internasional, Jumlah Produksi Domestik Dan Nilai Tukar Terhadap Nilai Ekspor Tembakau Indonesia (Studi Ekspor Tembakau Indonesia Tahun 1985-2014)

The main objective of this study is to understand and to explain the influence of International tobacco prices, number of domestic production and exchange rate against Indonesian tobacco export value. This type of research study is explanatory research with quantitative approach. This study used secondary data time series from the years from 1985 to 2014. Data was analyzed further by multiple linear regression analysis with the support of IBM SPSS Statistics program 20. The results of this study Is, International tobacco prices, number of domestic production and exchange rate simultaneous affected the value of Indonesia's tobacco exports significantly. Partial test in this research study showed that the International tobacco prices, number of domestic production and the exchange rate significantly affected of Indonesia tobacco exports value. Based on the results, it is recommended for Indonesia to sign and participate in FCTC Treaty in order to protect the tobacco industry in the country and improve the competitiveness of Indonesia tobacco in in the global market

Error analysis of the quartic nodal expansion method for slab geometry

This paper presents an analysis of the quartic polynomial Nodal Expansion Method (NEM) for one-dimensional neutron diffusion calculations. As part of an ongoing effort to develop an adaptive mesh refinement strategy for use in state-of-the-art nodal kinetics codes, we derive a priori error bounds on the computed solution for uniform meshes and validate them using a simple test problem. Predicted error bounds are found to be greater than computed maximum absolute errors by no more than a factor of six allowing mesh size selection to reflect desired accuracy. We also quantify the rapid convergence in the NEM computed solution as a function of mesh size

A P(X3TERIORI ERROR ESTIMATION FOR A NODAL METHOD IN NEUTRON TRANSPORT CALCULATIONS

Abstract. An a posterior error analysis of the spatial approximation is devehped for the oneiiimensiontd Arbitrarily High Order Transport-Nodal method E41eerror estimator preserves the order of convergence of the method when the mesh size tends to zero with respect to the L=norm. It is based on the di~erence between two discrete solutions that are~amiiable from the analysis. I%e proposed estimator is decomposed into error indicators to aiiow the quantification of local errors. Some test problems with isotropic scattering are solved to compare~he behavior of the tnie error to that of the estimated error

Proving Determinacy of the PharOS Real-Time Operating System

International audienceExecutions in the PharOS real-time system are deterministic in the sense that the sequence of local states for every process is independent of the order in which processes are scheduled. The essential ingredient for achieving this property is that a temporal window of execution is associated with every instruction. Messages become visible to receiving processes only after the time window of the sending message has elapsed. We present a high-level model of PharOS in TLA+ and formally state and prove determinacy using the TLA+ Proof System

Origin of the Breno and Esino dolomites in the western Southern Alps (Italy): Implications for a volcanic influence

The Esino Limestone of the western Southern Alps represents a differentiated Ladinian-Lower Carnian (?) carbonate platform comprised of margin, slope and peritidal inner platform facies up to 1000 m thick. A major regional subaerial exposure event lead to coverage by another peritidal Lower Carnian carbonate platform (Breno Formation). Multiphase dolomitization affected the carbonate sediments. Petrographic examinations identified at least three main generations of dolomites (D1, D2, and D3) that occur as both replacement and fracture-filling cements. These phases have crystal-size ranges of 3e35 mm (dolomicrite D1), 40e600 mm (eu-to subhedral crystals D2), and 200 mm to 5 mm (cavity- and fracture-filling anhedral to subhedral saddle dolomite D3), respectively. The fabric retentive near-micritic grain size coupled with low mean Sr concentration (76 \ub1 37 ppm) and estimated d18O of the parent dolomitizing fluids of D1 suggest formation in shallow burial setting at temperature ~ 45e50 C with possible contributions from volcanic-related fluids (basinal fluids circulated in volcaniclastics or related to volcanic activity), which is consistent with its abnormally high Fe (4438 \ub1 4393 ppm) and Mn (1219 \ub1 1418 ppm) contents. The larger crystal sizes, homogenization temperatures (D2, 108 \ub1 9 C; D3, 111 \ub1 14 C) of primary two-phase fluid inclusions, and calculated salinity estimates (D2, 23 \ub1 2 eq wt% NaCl; D3, 20 \ub1 4 eq wt% NaCl) of D2 and D3 suggest that they formed at later stages under mid-to deeper burial settings at higher temperatures from dolomitizing fluids of higher salinity, which is supported by higher estimated d18O values of their parent dolomitizing fluids. This is also consistent with their high Fe (4462 \ub1 4888 ppm; and 1091 \ub1 1183 ppm, respectively) and Mn (556 \ub1 289 ppm and 1091 \ub1 1183 ppm) contents, and low Sr concentrations (53 \ub1 31 ppm and 57 \ub1 24 ppm, respectively). The similarity in shale-normalized (SN) REE patterns and Ce (Ce/Ce*)SN and La (Pr/Pr*)SN anomalies of the investigated carbonates support the genetic relationship between the dolomite generations and their calcite precursor. Positive Eu anomalies, coupled with fluid-inclusion gas ratios (N2/Ar, CO2/CH4, Ar/He), high F concentration, high F/Cl and high Cl/Br molar ratios suggest an origin from diagenetic fluids circulated through volcanic rocks, which is consistent with the co-occurrence of volcaniclastic lenses in the investigated sequence

Computational Modelling of Genome-Side Transcription Assembly Networks Using a Fluidics Analogy

Understanding how a myriad of transcription regulators work to modulate mRNA output at thousands of genes remains a fundamental challenge in molecular biology. Here we develop a computational tool to aid in assessing the plausibility of gene regulatory models derived from genome-wide expression profiling of cells mutant for transcription regulators. mRNA output is modelled as fluid flow in a pipe lattice, with assembly of the transcription machinery represented by the effect of valves. Transcriptional regulators are represented as external pressure heads that determine flow rate. Modelling mutations in regulatory proteins is achieved by adjusting valves' on/off settings. The topology of the lattice is designed by the experimentalist to resemble the expected interconnection between the modelled agents and their influence on mRNA expression. Users can compare multiple lattice configurations so as to find the one that minimizes the error with experimental data. This computational model provides a means to test the plausibility of transcription regulation models derived from large genomic data sets