bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Reduced and Conventional Phase Equilibrium Calculations
Authors: Gorucu S. E. , Johns R. T. 
Published: March 2013

Abstract
Phase equilibrium calculations become computationally intensive in compositional simulation as the number of components and phases increase. Reduced methods were developed to address this problem where the binary interaction parameter (BIP) matrix is either approximated by spectral decomposition (Hendriks and van Bergen, 1992), or by using a two-parameter BIP formula (Li and Johns, 2006). Haugen and Beckner (2011) and Yan et al. (2011), however, recently stated that the spectral decomposition method, and by reference all reduced methods, are not as fast as previously reported in the literature. In this paper we present the first study that compares all eight reduced and conventional methods published to date using optimized code and compilers.
The results show that the spectral decomposition method and its variants are not as fast as other reduced methods, and can be slower than the conventional approach when fewer than 20 components are used. The reason for the slow speed is the additional number of nested loops required in the code and the requirement that the code must allow for a variable number of eigenvalues. We show that the reduced method of Li and Johns (2006) and its variants, however, are significantly faster. Significant speed up in flash calculations is achieved for all fluids studied when more than six components are used. For example, for ten-component fluids, a speed up of 2 to 3 in the computational time for Newton-Raphson iterations are obtained compared to the conventional method based on minimization of Gibbs energy. We also demonstrate that the reduced method by Gorucu and Johns (2011, 2013), an offshoot of the Li and Johns (2006) reduced approach, is more robust than all other methods.
Unlocking Fast Reservoir Predictions via Non-Intrusive Reduced Order Models
Authors: Klie Hector 
Published: March 2013

Abstract
The present paper proposes a novel non-intrusive model reduction approach based on Proper Orthogonal Decomposition (POD), the Discrete Empirical Interpolation Method (DEIM) and Radial Basis Function (RBF) networks to efficiently predict production of oil and gas reservoirs. Provided a representative set of training reservoir scenarios, either POD or DEIM allows for effectively projecting input parameters (e.g., permeability, porosity), states (e.g., pressure, saturations) and outputs (e.g., well production curves) into a much lower dimension that retains the main features contained in the simulation system. In this work, these projections are applied across multiple levels to be able to collapse a large number of spatio-temporal correlations. It is observed that these projections can be effectively performed at a large extent regardless of the underlying geological complexity and operational constraints associated with the reservoir model. The RBF network provides a powerful means for developing learning functions from input-output relationships described by the reservoir dynamics entailed by multiple combinations of inputs and controls. In order to achieve a high degree of predictability from the resulting reduced model, the RBF network exploits locality by a means of Gaussian basis functions that are maximal at the sampled point and decrease monotonically with distance. Compared to multilayer perceptron networks (i.e., traditional artificial neural networks) RBF networks require less training and are less sensitive to the presence of noise in the data. In this regard, POD or DEIM acts as a data filter that additionally aids at designing a more compact RBF network representation suitable for targeting fast reservoir predictions. Numerical results show significant accelerations with respect to running the original simulation model on a set of field-motivated cases.
Fast Simulation of Polymer Injection in Heavy-Oil Reservoirs Based on Topological Sorting and Sequential Splitting
Authors: Lie Knut-Andreas , Nilsen Halvor Møll , Rasmussen Atgeirr Flø , Raynaud Xavier 
Published: March 2013

Abstract
We present a set of algorithms for sequential solution of flow and transport that can be used for efficient simulation of polymer injection modeled as a two-phase system with rock compressibility and equal fluid compressibilities. Our formulation gives a set of nonlinear transport equations that can be discretized with standard implicit upwind methods to conserve mass and volume independent of the time step. In the absence of gravity and capillary forces, the splitting is unconditionally stable and the resulting nonlinear system of discrete transport equations can be permuted to lower triangular form by using a simple topological-sorting method from graph theory. This gives an optimal nonlinear solver that computes the solution cell by cell with local iteration control. The single-cell systems can be reduced to a nested set of nonlinear scalar equations that can be bracketed and solved with standard gradient or root-bracketing methods. The resulting method gives orders-of-magnitude reduction in runtimes and increases the feasible time-step sizes. For cases with gravity, the same method can be applied as part of a nonlinear Gauss-Seidel method. Altogether, our results demonstrate that sequential splitting combined with standard upwind discretizations can become a viable alternative to streamline methods for speeding up simulation of advection-dominated systems.
Generalized Field Development Optimization Using Derivative-Free Procedures
Authors: Isebor Obiajulu J. , Ciaurri David Echeverría , Durlofsky Louis J. 
Published: March 2013

Abstract
The optimization of general oil field development problems is considered. Techniques are presented to simultaneously determine the optimal number and type of new wells, the sequence in which they should be drilled, and their corresponding locations and (time-varying) controls. The optimization is posed as a mixed-integer nonlinear programming (MINLP) problem and involves categorical, integer-valued, and real-valued variables. The formulation handles bound, linear, and nonlinear constraints; the latter are treated using filter-based techniques. Noninvasive derivative-free approaches are applied for the optimizations. Methods considered include Branch and Bound (B&B, a rigorous global search procedure that requires relaxation of the categorical variables), Mesh Adaptive Direct Search (MADS, a local pattern search method), Particle Swarm Optimization (PSO, a heuristic global search method) and a PSO-MADS hybrid. Three example cases involving two-dimensional channelized reservoir models are presented. The PSO-MADS hybrid is shown to consistently outperform the standalone MADS and PSO procedures. In the two cases in which B&B is applied, the heuristic PSO-MADS approach is shown to give comparable solutions but at much lower computational cost. This is significant since B&B provides exhaustive search capabilities. We conclude that, although it is demanding in terms of computation, the methodology presented here appears to be applicable for realistic reservoir management.
An Analytical Quasi-Newton Method for EOS Calculations
Authors: Haugen Kjetil B. , Beckner Bret L. 
Published: March 2013

Abstract
The matrix of binary interaction coefficients appearing in the van der Waals mixing rules for cubic equations of state is often rank-deficient. If the rank is sufficiently low, phase equilibrium algorithms can take advantage of the Sherman-Morrison-Woodbury formula to solve the linear system of equations appearing in the Newton iterations more economically than using LU- or Cholesky factorization. Frequently, many binary interaction coefficients are very small, implying that a good approximation of even lower rank may exist. Using the low-rank approximation when generating the Jacobian and Hessian matrices leads to a quasi-Newton method. The approach reduces the cost of applying the Sherman-Morrison-Woodbury formula. The results of a series of bench-marks show that the Sherman-Morrison-Woodbury formula can significantly speed-up phase equilibrium calculations in mixtures with a large number of components.
An Efficient Multicore Linear Solver for Reservoir Simulation Applications
Authors: Pravilnikov V. , Diyankov O. , Diyankova S. , Beckner B. , Mishev I. 
Published: March 2013

Abstract
We present a suite of algorithms for the iterative solution of linear systems of algebraic equations arising in reservoir simulations. Usually, the solution of linear systems is the most time-consuming part of reservoir simulations, especially for complex physical models. Significant progress in multi-core architectures in the last decade allows now to solve large and complex problems on desktop computers. Moreover, multi-core algorithms can be naturally used as building blocks in hybrid (MPI+SMP) linear solvers.
The suite includes the following parallel algorithms: one partitioner, four preconditioners, and several iterative methods. The partitioner smpKWPT implements a multilevel p-way graph partitioning (similar to METIS) for multicore architectures. It generates partitions with quality similar or better than quality of the partitions produced by METIS. Three parallel preconditioners OverlapFILU, RecursiveFILU, and MultiLevelILUC are intended for preconditioning general matrices, and one preconditioner MultiLevelRIC - for SPD matrices. OverlapFILU implements the most efficient Additive Schwarz algorithms. RecursiveFILU is based on non-overlapping domain decomposition paradigm with parallel truncated factorization of the domain matrices and factorization of the interface matrix. MultiLevelILUC and MultiLevelRIC implement a parallel multilevel framework based on 2x2 splitting with a good quality leading diagonal block and a second diagonal block, containing the Schur complement, which is an initial matrix for the next level. These preconditioners are very robust even for extremely ill conditioned matrices. Several iterative methods are available with an option to control the convergence by the true residuals.
The parallel algorithms are based on very efficient serial algorithms and a highly optimized multi-thread computational core. The solver’s workflow is optimized for application in multi-step and multi-right-hand-side simulations. The parallel efficiency of the solver is demonstrated on several real field models. The multi-core solver usually provides 1.8-3.0 times speed-up on 4 cores and 2.5-4.0 on 8 cores. The performance of our algorithms is considerably better than the performance of the similar algorithms in Trilinos and PETSc as shown by examples.
Respiratory Colonization by Kingella kingae, Person-to-Person Transmission, and Pathogenesis of Invasive Infection
Authors: Yagupsky Pablo 
Published: March 2013

Increasing recognition of Kingella kingae as an important pathogen of early childhood in recent years has
elicited interest in the study of the asymptomatic carriage of the organism, its dissemination in the human population, and
the role played by colonization of the upper respiratory tract in the pathogenesis of K. kingae invasion of the skeletal
system and the endocardium.
Research has revealed that K. kingae is a frequent component of the normal oropharyngeal microbiota, disclosed the
subtle molecular mechanisms responsible for adherence of the bacterium to the pharyngeal mucosa, and revealed the
presence of a potent RTX toxin, probably implicated in breaching the epithelial barrier, survival of the organism in the
bloodstream, and damage to bone and joint tissues. Epidemiological studies have shown that carriage of K. kingae peaks
in 6-30 month-old children, coinciding with the age of increased susceptibility to invasive disease, and daycare-center
attendance represent a significant risk factor for pharyngeal colonization. The organism is transmitted from person-toperson
by close contact between family members, playmaytes, and day-care center attendees. Carriage is characterized by
frequent turnover of colonizing strains, similar to what has been described in other pathogens of respiratory origin.
Hypercapnia Accelerates Wound Healing in Endothelial Cell Monolayers Exposed to Hypoxia
Authors: Tsuji Takao , Aoshiba Kazutetsu , Itoh Masayuki , Nakamura Hiroyuki , Yamaguchi Kazuhiro 
Published: March 2013

Introduction:While tissue hypoxia is known to play a critical role in the process of vascular injury and repair, the effect of hypercapnia on this process remains uncertain. We investigated whether hypercapnia might influence endothelial cell wound healing under the influence of hypoxia.Materials and Methodology:Monolayers of human umbilical venous endothelial cells (HUVECs) were scratch-wounded and incubated under different levels of O2, CO2, and pH in the environment.Results:Inhibition of wound healing was observed in the HUVEC monolayers under the hypoxic condition as compared to the normoxic condition. Both hypercapnic acidosis and buffered hypercapnia, but not normocapnic acidosis improved the rate of wound healing under the influence of hypoxia. The beneficial effect of hypercapnia was associated with stimulation of cell proliferation, without effects on cell adhesion, migration or apoptosis. On the other hand, the stimulatory effect of hypercapnia on wound healing and cell proliferation was not noted under normoxic conditions.Conclusion:These results suggest that hypercapnia, rather than acidosisper se, accelerated the wound healing in HUVEC monolayers cultured under hypoxic conditions. The effect of hypercapnia on wound healing was due, at least in part, to the stimulation of cell proliferation by hypercapnia.
Tigecycline Versus Levofloxacin in Hospitalized Patients
With Community-Acquired Pneumonia: An Analysis of
Risk Factors
Authors: Dartois Nathalie , Cooper C Angel , Castaing Nathalie , Gandjini Hassan , Sarkozy Denise 
Published: March 2013

Introduction:
This study was conducted to evaluate the efficacy of tigecycline (TGC) versus levofloxacin (LEV) in hospitalized patients with community-acquired pneumonia (CAP) using pooled data and to perform exploratory analyses of risk factors associated with poor outcome.

Materials and Methodology:
Pooled analyses of 2 phase 3 studies in patients randomized to intravenous (IV) TGC (100 mg, then 50 mg q12h) or IV LEV (500 mg q24h or q12h). Clinical responses at test of cure visit for the clinically evaluable (CE) and clinical modified intention to treat populations were assessed for patients with risk factors including aged ≥65 years, prior antibiotic failure, bacteremia, multilobar disease, chronic obstructive pulmonary disease, alcohol abuse, altered mental status, hypoxemia, renal insufficiency, diabetes mellitus, white blood cell count >30 x 109/L or <4 x 109/L, CURB-65 score ≥2, Fine score category of III to V and at least 2 clinical instability criteria on physical examination.

Results:
In the CE population of 574 patients, overall cure rates were similar: TGC (253/282, 89.7%); LEV (252/292, 86.3%). For all but one risk factor, cure rates for TGC were similar to or higher than those for LEV. For individual risk factors, the greatest difference between treatment groups was observed in patients with diabetes mellitus (difference of 22.9 for TGC versus LEV; 95% confidence interval, 4.8 - 39.9).

Conclusions:
TGC achieved cure rates similar to those of LEV in hospitalized patients with CAP. For patients with risk factors, TGC provided generally favorable clinical outcomes.
AKI Transition of Care
Authors: Goldstein Stuart L. , Jaber Bertrand L. , Faubel Sarah , Chawla Lakhmir S. 
Published: March 2013

Summary
The incidence rate of AKI is increasing across the spectrum of hospitalized children and adults. Given the increased morbidity and mortality associated with AKI, significant research effort has been appropriately focused on standardizing AKI definitions, identifying risk factors, and discovering and validating novel, earlier structural biomarkers of kidney injury. In addition, a growing body of evidence demonstrates that AKI is a risk factor for the future development or accelerated progression of CKD. Unfortunately, prospective observational studies have not consistently followed survivors of episodes of AKI for longitudinal outcomes after hospital discharge, which could lead to ascertainment bias in terms of over- or underestimation of CKD development. Furthermore, data show that clinical follow-up of AKI survivors is low. This lack of systematic study and clinical follow-up represents a potential missed opportunity to prevent chronic disease after an acute illness and improve outcomes. Therefore, prospective study of transitions of care after episodes of AKI is needed to identify which patients are at risk for CKD development and to optimally target therapeutic interventions.
Costs and Benefits of Requiring an Engagement Partner Signature: Recent Experience in the United Kingdom
Authors: Carcello Joseph V. , Li Chan 
Published: March 2013

ABSTRACT:
This paper investigates the effects on audit quality and audit fees of requiring the engagement partner to sign the audit report in the United Kingdom (U.K.). The effect of requiring the engagement partner to sign the audit report is timely since the Public Company Accounting Oversight Board (PCAOB) is considering mandating a similar requirement in the United States (U.S.). In the first year after the introduction of the signature requirement, we find a significant decline in abnormal accruals and the propensity to meet an earnings threshold, and we find a significant increase in the incidence of qualified audit reports and in earnings informativeness. In addition, audit fees are significantly higher in the post-signature period than in the pre-signature period. Moreover, we compare U.K. firms with a matched sample of U.S. firms and firms in other European countries in periods both before and after the U.K. adopted a signature requirement. Our results are generally consistent with the argument of improved audit quality in U.K. firms after the signature requirement is adopted.
Data Availability: Data are available from public sources identified in the text.
Arborista, Inc.: An Instructional Resource Case
Authors: Picconi Marc P. , Smith Kimberly J. , Woods Alexander 
Published: March 2013

ABSTRACT:
This deceptively simple case is intended for use as early as the first day of an M.B.A. core accounting course or as a focused review for an undergraduate accounting course. It achieves three primary objectives: accelerating student learning about the statement of cash flows, emphasizing the importance of both the cash flow statement and the income statement in valuation and capital markets, and introducing the three primary financial statements as an integrated system. The case also features the use of the direct method of presenting operating cash flows, both as a pedagogical tool and to allow interested instructors to increase their focus on that method. We have found that students benefit from the early integration of the cash flow statement, as well as the ability to clearly understand how operating cash flows are similar to—and different from—net income. Finally, the case provides an optional managerial accounting module for instructors who teach a course that integrates financial and managerial accounting.
The role of passive calcium influx through the cell membrane in galvanotaxis
Authors: Borys Przemysław 
Published: March 2013

AbstractPassive calcium influx is one of the theories to explain the cathodal galvanotaxis of cells that utilize the electric field to guide their motion. When exposed to an electric field, the intracellular fluid becomes polarized, leading to positive charge accumulation on the cathodal side and negative charge accumulation on the anodal side. The negative charge on the anodal side attracts extracellular calcium ions, increasing the anodal calcium concentration, which is supposed to decrease the mobile properties of this side. Unfortunately, this model does not capture the Ca2+ dynamics after its presentation to the intracellular fluid. The ions cannot permanently accumulate on the anodal side because that would build a potential drop across the cytoplasm leading to an ionic current, which would carry positive ions (not only Ca2+) from the anodal to the cathodal part through the cytoplasm. If the cytoplasmic conductance for Ca2+ is low enough compared to the membrane conductance, the theory could correctly predict the actual behavior. If the ions move through the cytoplasm at a faster rate, compensating for the passive influx, this theory may fail. This paper contains a discussion of the regimes of validity for this theory.
Design of tailing dam using red mud
Authors: Rout Subrat , Sahoo Tapaswini , Das Sarat 
Published: March 2013

Abstract
Red mud, waste industrial product from aluminum industries produced approximately 75 million tonnes every year with less than half of this is used. Storage of this unutilized red mud takes vast tracts of usable land and pollutes, land, air and water. Construction of high embankments, under passes, flyovers, tailing dams uses vast tract of natural resources (top soil) is also matter of concern as its takes thousands of years to form the natural soil. This paper discusses use of red mud for construction of tailing dam based on laboratory findings and finite element analysis. The geotechnical properties such as plasticity, compaction, permeability, shear strength characteristics and dispersion of red mud are presented. Stability and seepage analysis of tailing dams as per finite element analysis using the above geotechnical parameters is presented.
Catalogue of maximum crack opening stress for CC(T) specimen assuming large strain condition
Authors: Graba Marcin 
Published: March 2013

Abstract
In this paper, values for the maximum opening crack stress and its distance from crack tip are determined for various elastic-plastic materials for centre cracked plate in tension (CC(T) specimen) are presented. Influences of yield strength, the work-hardening exponent and the crack length on the maximum opening stress were tested. The author has provided some comments and suggestions about modelling FEM assuming large strain formulation.
Reviews
Authors: Walter Felix , Woodhouse  , Niebuhr Reinhold , Soward  
Published: March 2013

Emery Neff, A Revolution in European Poetry, 1660–1900, reviewed by Felix Walter M. M. Knappen, Tutor Purtitanism: A Chapter in the History of Idealism, reviewed by A. S. P. Woodhouse W. K. Jordan, The Develoopment of Religious Toleration in England from the Beginning of the English Reformation...to the Restoration, reviewed by A. S. P. Woodhouse Don M. Wolfe, Milton in the Puritan Revolution, reviewed by A. S. P. Woodhouse George Wesley Whiting, Milton's Literary Milieu, reviewed by A. S. P. Woodhouse Frank Allen Patterson, An Index to the Columbia Edition of the Works of John Milton, reviewed by A. S. P. Woodhouse Charles Norris Cochrane, Christianity and Classical Culture: A Study of Thought and Action from Augustus to Augustine, reviewed by Reinhold Niebuhr Clarence K. Streit, Union Now with Britain, reviewed by F. H. Soward
Reviews
Authors: Brown  , Taylor  , Glazebrook  , Scott  , Wilkinson  
Published: March 2013

Axel's Castle: A Study in the Imaginative Literature of 1870-1930, reviewed by E. K. Brown The Triple Thinkers, reviewed by E. K. Brown To the Finland Station: A Study in the Writing and Acting of History, reviewed by E. K. Brown The Wound and thc Bow: Seven Studies in Literature, reviewed by E. K. Brown The Boys in the Back Room: Notes on California Novelists, reviewed by E. K. Brown Reinhold Niebuhr, The Nature and Destiny of Man: A Christian Interpretation. I. Human Nature, reviewed by W. R. Taylor William E. Dodd and Martha Dodd, eds., Ambassador Dodd's Diary, 1933-1938, reviewed by G. deT. Glazebrook William L. Shirer, Berlin Diary: The Journal of a Foreign Correspondent, 1931–1941, reviewed by G. deT. Glazebrook F. H. Soward, J. F. Parkinson, N. A. M. MacKenzie, T. W. L. MacDermot Canada in World Affairs: The Pre-War Years, reviewed by F. R. Scott Raoul de Roussy de Sales, ed., My New Order, reviewed by G. deT. Glazebrook