Debates—Stochastic subsurface hydrology from theory to practice: why stochastic modeling has not yet permeated into practitioners?

This is the peer reviewed version of the following article: [Sanchez-Vila, X., and D. Fernàndez-Garcia (2016), Debates—Stochastic subsurface hydrology from theory to practice: Why stochastic modeling has not yet permeated into practitioners?, Water Resour. Res., 52, 9246–9258, doi:10.1002/2016WR019302], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2016WR019302/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingWe address modern topics of stochastic hydrogeology from their potential relevance to real modeling efforts at the field scale. While the topics of stochastic hydrogeology and numerical modeling have become routine in hydrogeological studies, nondeterministic models have not yet permeated into practitioners. We point out a number of limitations of stochastic modeling when applied to real applications and comment on the reasons why stochastic models fail to become an attractive alternative for practitioners. We specifically separate issues corresponding to flow, conservative transport, and reactive transport. The different topics addressed are emphasis on process modeling, need for upscaling parameters and governing equations, relevance of properly accounting for detailed geological architecture in hydrogeological modeling, and specific challenges of reactive transport. We end up by concluding that the main responsible for nondeterministic models having not yet permeated in industry can be fully attributed to researchers in stochastic hydrogeology.Peer ReviewedPostprint (author's final draft

Growth in non-Laplacian fields

We develop a formal method for assigning rules to lattice-based walkers which allows the modeling of irreversible growth in systems governed by non-Laplacian partial differential equations. The method is used to study diffusive growth in finite concentration fields. Good agreement with analytic results is obtained. The method is subsequently applied to study electrochemical deposition and investigate the interplay between the electrostatic and diffusion fields. We examine the effect of a local (nonuniform) flow field on deposition on a substrate

Research in progress in applied mathematics, numerical analysis, fluid mechanics, and computer science

This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics, fluid mechanics, and computer science during the period October 1, 1993 through March 31, 1994. The major categories of the current ICASE research program are: (1) applied and numerical mathematics, including numerical analysis and algorithm development; (2) theoretical and computational research in fluid mechanics in selected areas of interest to LaRC, including acoustics and combustion; (3) experimental research in transition and turbulence and aerodynamics involving LaRC facilities and scientists; and (4) computer science

Development of stable operator splitting numerical algorithms for phase-field modeling and surface diffusion applications

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 35-37).Implicit, explicit and spectral algorithms were used to create Allen-Cahn and Cahn-Hilliard phase field models. Individual terms of the conservation equations were approached by different methods using operator splitting techniques found in previous literature. In addition, dewetting of gold films due to surface diffusion was modeled to present the extendability and efficiency of the spectral methods derived. The simulations developed are relevant to many real systems and are relatively light in computational load because they take large time steps to drive the model into equilibrium. Results were analyzed by their relevancy to real world applications and further work in this field is outlined.by Matthew Dane Handler.S.B

Benefits or Harms of No Child Left Behind

ABSTRACT BENEFITS OR HARMS OF NO CHILD LEFT BEHIND by Judy Block The No Child Left Behind Act of 2001 reauthorizes and extensively amends the Elementary and Secondary Education Act of 1965 and establishes control over the majority of federal programs and spending that affect public education. Embedded in the Act are various requirements that states and schools must adhere to as a condition of receiving federal education funds as well as harsh sanctions for failing to meet the requirements. No Child Left Behind notably shifts federal education policy by expanding its role into the areas of standards and assessment, accountability, curricula, discipline and administration, and providership. The Act also exacerbates tensions and blurs the line between competing ideologies of the role and nature of public education. NCLB\u27s dominant reliance on proven research methods and statistical data, and its provisions regarding student assessment, failing schools, and parental choice open the schoolhouse door to commercial marketteers, further transforming public education into a consumer good, classrooms into marketplaces, and students and teachers into immaterial byproducts. No Child Left Behind\u27s requirements often have more than one result, with some results doing more harm than the Act\u27s stated good. The principle of double effect (PDE) provides a lens to evaluate instances where there are two effects of a single act; that is,PDE can explain the permissibility of an action that causes an undesired or harmful effect secondary to promoting some good end. By using philosophical analysis generally, and the principle of double effect specifically, this dissertation examines No Child Left Behind’s implementation requirements, specific programs, and their effects to determine the Act\u27s benefits or harms. The dissertation proceeds with a review of NCLB\u27s historical context and key features, an introduction to the principle of double effect, and a discussion of democratic and market ideologies and their relationship with education. This dissertation recognizes the various populations affected by the Act, but focuses specifically on students with disabilities and the relationship of the principle of double effect to the implications of NCLB. Chapter Four extends the principle of double effect to NCLB\u27s implementation requirements and specific programs to identify their consequences or effects. The dissertation concludes with a synthesis of the questions and problems presented by NCLB and the implications for students, teachers, public education, and our communities

Radiation Transfer of Energy in Arc Plasma

Hlavním cílem práce je studium radiačního přenosu energie v termálním plazmatu pomocí aproximační metody sférických harmonických funkcí (PN-aproximace). Práce má teoretický charakter. Pozornost je věnována především P1-aproximaci. Spektrální závislost absorpčních koeficientů byla zpracována pomocí multigroup aproximace. Byl vytvořen výpočetní program pro výpočet radiačních charakteristik v izotermickém válcovém plazmatu a ve válcovém plazmatu s daným teplotním profilem, a vypočteny radiační charakteristiky pro plazma vzduchu a směsí SF6 a PTFE. Získané výsledky umožňují zahrnout radiační ztráty energie do celkové energetické bilance plazmatu elektrického oblouku. Jsou využívány v matematických modelech elektrického oblouku, které vytváří naši spolupracovníci z Ústavu fyziky plazmatu AV ČR v Praze a také ze zahraničních pracovišť (ABB Corporate Research ve Švýcarsku a Siemens AG Corporate Technology v Německu).The main task of this work is to investigate the radiation transfer in thermal plasmas using the approximate method of spherical harmonic functions (PN-approximation). The thesis is of theoretical nature. Main attention was given to the most popular P1-approximation. Spectral dependence of absorption coefficients was handled by means of multigroup approximation. The computational code for calculation of radiation characteristics in isothermal plasma cylinder and in plasma cylinder with given temperature profile was prepared. Radiation characteristics of air plasma and plasma mixture of SF6 and PTFE were calculated. Obtained results account for data for including radiation losses into the total energy balance of arc plasma. They are used in mathematical models of electric arcs created by our collaborators from Institute of Plasma Physics Academy of Science in Prague and from abroad (ABB Corporate Research, Switzerland and Siemens AG Corporate Technology, Germany).

Semiannual final report, 1 October 1991 - 31 March 1992

A summary of research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics, numerical analysis, and computer science during the period 1 Oct. 1991 through 31 Mar. 1992 is presented

Simulation of hot carriers in semiconductor devices

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 109-113).by Khalid Rahmat.Ph.D

Simulation of iron impurity gettering in crystalline silicon solar cells

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 52-56).This work discusses the Impurity-to-Efficiency (12E) simulation tool and applet. The 12E simulator models the physics of iron impurity gettering in silicon solar cells during high temperature processing. The tool also includes a device simulator to calculate cell performance after processing. By linking input materials, processing, and cell performance, 12E enables accelerated solar cell optimization. Herein, background information on the economic drivers of solar cell installations and manufacturing are used to introduce the importance of iron impurity engineering. The fundamental physics of gettering and the development of the numerical methods employed by the tool are presented. The development, deployment, and use of the web applet are also discussed.by Douglas M. Powell.S.M

Simulation of hot carriers in semiconductor devices

Includes bibliographical references (p. 109-113).Supported by the U.S. Navy. N00174-93-C-0035Khalid Rahmat