Science.gov

Sample records for computer oriented energy

  1. SOLINS- SOLAR INSOLATION MODEL FOR COMPUTING AVAILABLE SOLAR ENERGY TO A SURFACE OF ARBITRARY ORIENTATION

    NASA Technical Reports Server (NTRS)

    Smith, J. H.

    1994-01-01

    This computer program, SOLINS, was developed to aid engineers and solar system designers in the accurate modeling of the average hourly solar insolation on a surface of arbitrary orientation. The program can be used to study insolation problems specific to residential and commercial applications where the amount of space available for solar collectors is limited by shadowing problems, energy output requirements, and costs. For tandem rack arrays, SOLINS will accommodate the use of augmentation reflectors built into the support structure to increase insolation values at the collector surface. As the use of flat plate solar collectors becomes more prevalent in the building industry, the engineer and designer must have the capability to conduct extensive sensitivity analyses on the orientation and location of solar collectors. SOLINS should prove to be a valuable aid in this area of engineering. SOLINS uses a modified version of the National Bureau of Standards model to calculate the direct, diffuse, and reflected components of total insolation on a tilted surface with a given azimuthal orientation. The model is based on the work of Liu and Jordan with corrections by Kusuda and Ishii to account for early morning and late afternoon errors. The model uses a parametric description of the average day solar climate to generate monthly average day profiles by hour of the insolation level on the collector surface. The model includes accommodation of user specified ground and landscape reflectivities at the collector site. For roof or ground mounted, tilted arrays, SOLINS will calculate insolation including the effects of shadowing and augmentation reflectors. The user provides SOLINS with data describing the array design, array orientation, the month, the solar climate parameter, the ground reflectance, and printout control specifications. For the specified array and environmental conditions, SOLINS outputs the hourly insolation the array will receive during an average day

  2. A Computer Oriented Problem Solving Unit, Consume. Student Guide. Computer Technology Program Environmental Education Units.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    This is the student guide in a set of five computer-oriented environmental/energy education units. Contents are organized into the following parts or lessons: (1) introduction to power and energy; (2) energy consumption and supply; (3) energy conservation and distribution; (4) energy flow and the question of transportation; and (5) computer models…

  3. "Smart Computing"--Orienting Your Students.

    ERIC Educational Resources Information Center

    Millis, Paul J.

    This paper discusses how to present new college students with their initial exposure to policy, security, and ethical computing issues. The Office of Policy Development and Education participates in summer orientation to introduce students to proper use of information technology resources at the University of Michigan. This presentation is known…

  4. Object-oriented Tools for Distributed Computing

    NASA Technical Reports Server (NTRS)

    Adler, Richard M.

    1993-01-01

    Distributed computing systems are proliferating, owing to the availability of powerful, affordable microcomputers and inexpensive communication networks. A critical problem in developing such systems is getting application programs to interact with one another across a computer network. Remote interprogram connectivity is particularly challenging across heterogeneous environments, where applications run on different kinds of computers and operating systems. NetWorks! (trademark) is an innovative software product that provides an object-oriented messaging solution to these problems. This paper describes the design and functionality of NetWorks! and illustrates how it is being used to build complex distributed applications for NASA and in the commercial sector.

  5. Cloudbus Toolkit for Market-Oriented Cloud Computing

    NASA Astrophysics Data System (ADS)

    Buyya, Rajkumar; Pandey, Suraj; Vecchiola, Christian

    This keynote paper: (1) presents the 21st century vision of computing and identifies various IT paradigms promising to deliver computing as a utility; (2) defines the architecture for creating market-oriented Clouds and computing atmosphere by leveraging technologies such as virtual machines; (3) provides thoughts on market-based resource management strategies that encompass both customer-driven service management and computational risk management to sustain SLA-oriented resource allocation; (4) presents the work carried out as part of our new Cloud Computing initiative, called Cloudbus: (i) Aneka, a Platform as a Service software system containing SDK (Software Development Kit) for construction of Cloud applications and deployment on private or public Clouds, in addition to supporting market-oriented resource management; (ii) internetworking of Clouds for dynamic creation of federated computing environments for scaling of elastic applications; (iii) creation of 3rd party Cloud brokering services for building content delivery networks and e-Science applications and their deployment on capabilities of IaaS providers such as Amazon along with Grid mashups; (iv) CloudSim supporting modelling and simulation of Clouds for performance studies; (v) Energy Efficient Resource Allocation Mechanisms and Techniques for creation and management of Green Clouds; and (vi) pathways for future research.

  6. Development of site-oriented Analytics for Grid computing centres

    NASA Astrophysics Data System (ADS)

    Washbrook, A.; Crooks, D.; Roy, G.; Skipsey, S.; Qin, G.; Stewart, G. P.; Britton, D.

    2015-12-01

    The field of analytics, the process of analysing data to visualise meaningful patterns and trends, has become increasingly important in scientific computing as the volume and variety of data available to process has significantly increased. There is now ongoing work in the High Energy Physics (HEP) community in this area, for example in the augmentation of systems management at WLCG computing sites. We report on work evaluating the feasibility of distributed site-oriented analytics using the Elasticsearch, Logstash and Kibana software stack and demonstrate functionality by the application of two workflows that give greater insight into site operations.

  7. Computational Modeling of Magnetically Actuated Propellant Orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    sufficient performance to support cryogenic propellant management tasks. In late 1992, NASA MSFC began a new investigation in this technology commencing with the design of the Magnetically-Actuated Propellant Orientation (MAPO) experiment. A mixture of ferrofluid and water is used to simulate the paramagnetic properties of LOX and the experiment is being flown on the KC-135 aircraft to provide a reduced gravity environment. The influence of a 0.4 Tesla ring magnet on flow into and out of a subscale Plexiglas tank is being recorded on video tape. The most efficient approach to evaluating the feasibility of MAPO is to compliment the experimental program with development of a computational tool to model the process of interest. The goal of the present research is to develop such a tool. Once confidence in its fidelity is established by comparison to data from the MAPO experiment, it can be used to assist in the design of future experiments and to study the parameter space of the process. Ultimately, it is hoped that the computational model can serve as a design tool for full-scale spacecraft applications.

  8. Computer Oriented Exercises on Attitudes and U.S. Gasoline Consumption, Attitude. Student Guide. Computer Technology Program Environmental Education Units.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    This is the student guide in a set of five computer-oriented environmental/energy education units. Contents of this guide present: (1) the three gasoline consumption-reducing options for which attitudes are to be explored; (2) exercises; and (3) appendices including an energy attitudes survey. (MR)

  9. Calculus: A Computer Oriented Presentation, Part 1 [and] Part 2.

    ERIC Educational Resources Information Center

    Stenberg, Warren; Walker, Robert J.

    Parts one and two of a one-year computer-oriented calculus course (without analytic geometry) are presented. The ideas of calculus are introduced and motivated through computer (i.e., algorithmic) concepts. An introduction to computing via algorithms and a simple flow chart language allows the book to be self-contained, except that material on…

  10. Manage Energy with Computers.

    ERIC Educational Resources Information Center

    American School and University, 1982

    1982-01-01

    Computerized energy management at Drew University (New Jersey) is accomplished by direct digital control in which microprocessor controllers control, monitor, and carry out energy management functions at the equipment level. (Author/MLF)

  11. Terminal-oriented computer-communication networks.

    NASA Technical Reports Server (NTRS)

    Schwartz, M.; Boorstyn, R. R.; Pickholtz, R. L.

    1972-01-01

    Four examples of currently operating computer-communication networks are described in this tutorial paper. They include the TYMNET network, the GE Information Services network, the NASDAQ over-the-counter stock-quotation system, and the Computer Sciences Infonet. These networks all use programmable concentrators for combining a multiplicity of terminals. Included in the discussion for each network is a description of the overall network structure, the handling and transmission of messages, communication requirements, routing and reliability consideration where applicable, operating data and design specifications where available, and unique design features in the area of computer communications.

  12. Computational modeling of magnetically actuated propellant orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    Unlike terrestrial applications where gravity positions liquid at the 'bottom' of the tank, the location of liquid propellant in spacecraft tanks is uncertain unless specific actions are taken or special features are built into the tank. Some mission events require knowledge of liquid position prior to a particular action: liquid must be positioned over the tank outlet prior to starting the main engines and must be moved away from the tank vent before vapor can be released overboard to reduce pressure. It may also be desirable to positively position liquid to improve propulsion system performance: moving liquid away from the tank walls will dramatically decrease the rate of heat transfer to the propellant, suppressing the boil-off rate, thereby reducing overall mission propellant requirements. The process of moving propellant to a desired position is referred to as propellant orientation or reorientation. Several techniques have been developed to positively position propellant in spacecraft tanks and each technique imposes additional requirements on vehicle design. Propulsive reorientation relies on small auxiliary thrusters to accelerate the tank. The inertia of the liquid causes it to collect in the aft-end of the tank if the acceleration is forward. This technique requires that additional thrusters be added to the vehicle, that additional propellant be carried in the vehicle, and that an additional operational maneuver be executed. Another technique uses Liquid Acquisition Devices (LAD's) to positively position propellants. These devices rely on surface tension to hold the liquid within special geometries (i.e. vanes, wire-mesh channels, start-baskets). While avoiding some of the penalties of propulsive orientation, this technique requires the addition of complicated hardware inside the propellant tank and performance for long duration missions is uncertain. The subject of the present research is an alternate technique for positively positioning liquid within

  13. Steering object-oriented computations with Python

    SciTech Connect

    Yang, T.-Y.B.; Dubois, P.F.; Furnish, G.; Beazley, D.M.

    1996-10-01

    We have described current approaches and future plans for steering C++ application, running Python on parallel platforms, and combination of Tk interface and Python interpreter in steering computations. In addition, there has been significant enhancement in the Gist module. Tk mega widgets has been implemented for a few physics applications. We have also written Python interface to SIJLO, a data storage package used as an interface to a visualization system named MeshTv. Python is being used to control large-scale simulations (molecular dynamics in particular) running on the CM-5 and T3D at LANL as well. A few other code development projects at LLNL are either using or considering Python as their steering shells. In summary, the merits of Python have been appreciated by more and more people in the scientific computation community.

  14. Computer Oriented Exercises on Attitudes and U.S. Gasoline Consumption, Attitude. Teacher Guide. Computer Technology Program Environmental Education Units.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    This is the teacher's guide to accompany the student guide which together comprise one of five computer-oriented environmental/energy education units. This unit is concerned with the attitude of people toward gasoline shortages and different steps the government could take to reduce gasoline consumption. Through the exercises, part of which make…

  15. Working with Computers: Computer Orientation for Foreign Students.

    ERIC Educational Resources Information Center

    Barlow, Michael

    Designed as a resource for foreign students, this book includes instructions not only on how to use computers, but also on how to use them to complete academic work more efficiently. Part I introduces the basic operations of mainframes and microcomputers and the major areas of computing, i.e., file management, editing, communications, databases,…

  16. Generic, Type-Safe and Object Oriented Computer Algebra Software

    NASA Astrophysics Data System (ADS)

    Kredel, Heinz; Jolly, Raphael

    Advances in computer science, in particular object oriented programming, and software engineering have had little practical impact on computer algebra systems in the last 30 years. The software design of existing systems is still dominated by ad-hoc memory management, weakly typed algorithm libraries and proprietary domain specific interactive expression interpreters. We discuss a modular approach to computer algebra software: usage of state-of-the-art memory management and run-time systems (e.g. JVM) usage of strongly typed, generic, object oriented programming languages (e.g. Java) and usage of general purpose, dynamic interactive expression interpreters (e.g. Python) To illustrate the workability of this approach, we have implemented and studied computer algebra systems in Java and Scala. In this paper we report on the current state of this work by presenting new examples.

  17. An Object-Oriented Approach to Writing Computational Electromagnetics Codes

    NASA Technical Reports Server (NTRS)

    Zimmerman, Martin; Mallasch, Paul G.

    1996-01-01

    Presently, most computer software development in the Computational Electromagnetics (CEM) community employs the structured programming paradigm, particularly using the Fortran language. Other segments of the software community began switching to an Object-Oriented Programming (OOP) paradigm in recent years to help ease design and development of highly complex codes. This paper examines design of a time-domain numerical analysis CEM code using the OOP paradigm, comparing OOP code and structured programming code in terms of software maintenance, portability, flexibility, and speed.

  18. An object-oriented approach to energy-economic modeling

    SciTech Connect

    Wise, M.A.; Fox, J.A.; Sands, R.D.

    1993-12-01

    In this paper, the authors discuss the experiences in creating an object-oriented economic model of the U.S. energy and agriculture markets. After a discussion of some central concepts, they provide an overview of the model, focusing on the methodology of designing an object-oriented class hierarchy specification based on standard microeconomic production functions. The evolution of the model from the class definition stage to programming it in C++, a standard object-oriented programming language, will be detailed. The authors then discuss the main differences between writing the object-oriented program versus a procedure-oriented program of the same model. Finally, they conclude with a discussion of the advantages and limitations of the object-oriented approach based on the experience in building energy-economic models with procedure-oriented approaches and languages.

  19. Computation of gaze orientation under unrestrained head movements.

    PubMed

    Ronsse, Renaud; White, Olivier; Lefèvre, Philippe

    2007-01-15

    Given the high relevance of visual input to human behavior, it is often important to precisely monitor the spatial orientation of the visual axis. One popular and accurate technique for measuring gaze orientation is based on the dual search coil. This technique does not allow for very large displacements of the subject, however, and is not robust with respect to translations of the head. More recently, less invasive procedures have been developed that record eye movements with camera-based systems attached to a helmet worn by the subject. Computational algorithms have also been developed that can calibrate eye orientation when the head's position is fixed. Given that camera-based systems measure the eye's position in its orbit, however, the reconstruction of gaze orientation is not as straightforward when the head is allowed to move. In this paper, we propose a new algorithm and calibration method to compute gaze orientation under unrestrained head conditions. Our method requires only the accurate measurement of orbital eye position (for instance, with a camera-based system), and the position of three points on the head. The calculations are expressed in terms of linear algebra, so can easily be interpreted and related to the geometry of the human body. Our calibration method has been tested experimentally and validated against independent data, proving that is it robust even under large translations, rotations, and torsions of the head.

  20. Opportunities for Computational Discovery in Basic Energy Sciences

    NASA Astrophysics Data System (ADS)

    Pederson, Mark

    2011-03-01

    An overview of the broad-ranging support of computational physics and computational science within the Department of Energy Office of Science will be provided. Computation as the third branch of physics is supported by all six offices (Advanced Scientific Computing, Basic Energy, Biological and Environmental, Fusion Energy, High-Energy Physics, and Nuclear Physics). Support focuses on hardware, software and applications. Most opportunities within the fields of~condensed-matter physics, chemical-physics and materials sciences are supported by the Officeof Basic Energy Science (BES) or through partnerships between BES and the Office for Advanced Scientific Computing. Activities include radiation sciences, catalysis, combustion, materials in extreme environments, energy-storage materials, light-harvesting and photovoltaics, solid-state lighting and superconductivity.~ A summary of two recent reports by the computational materials and chemical communities on the role of computation during the next decade will be provided. ~In addition to materials and chemistry challenges specific to energy sciences, issues identified~include a focus on the role of the domain scientist in integrating, expanding and sustaining applications-oriented capabilities on evolving high-performance computing platforms and on the role of computation in accelerating the development of innovative technologies. ~~

  1. Surface orientation dependence of the activation energy of S diffusion in bcc Fe

    NASA Astrophysics Data System (ADS)

    Barnard, P. E.; Terblans, J. J.; Swart, H. C.

    2015-11-01

    The formation of vacancies in the low-index orientations of bcc Fe was studied by a combined computational modelling and experimental investigation by making use of density functional theory (DFT), Auger electron spectroscopy (AES), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray diffraction (XRD). Vacancies were considered to occur as a result of a Schottky defect forming in the bcc Fe lattice. This predicted a surface orientation dependence on the vacancy formation energy and consequently also on the activation energy of diffusion. Activation energies for the segregation of S in the Fe(1 0 0), Fe(1 1 0) and Fe(1 1 1) surface orientations were calculated by DFT modelling as 2.75 eV, 2.86 eV and 1.94 eV respectively. Simulations furthermore revealed a variation in the segregation kinetics of S as a result of the activation energy dependence on the surface orientation. Experimental data obtained by AES, TOF-SIMS and XRD confirmed this variation in the segregation kinetics of S segregation in different Fe orientations. This article provides compelling evidence for the formation of vacancies in bcc Fe to occur via the Schottky defect mechanism, which results in the orientation dependence for the activation energy of diffusion.

  2. Orientation-dependent binding energy of graphene on palladium

    SciTech Connect

    Kappes, Branden B.; Ebnonnasir, Abbas; Ciobanu, Cristian V.; Kodambaka, Suneel

    2013-02-04

    Using density functional theory calculations, we show that the binding strength of a graphene monolayer on Pd(111) can vary between physisorption and chemisorption depending on its orientation. By studying the interfacial charge transfer, we have identified a specific four-atom carbon cluster that is responsible for the local bonding of graphene to Pd(111). The areal density of such clusters varies with the in-plane orientation of graphene, causing the binding energy to change accordingly. Similar investigations can also apply to other metal substrates and suggests that physical, chemical, and mechanical properties of graphene may be controlled by changing its orientation.

  3. E-Governance and Service Oriented Computing Architecture Model

    NASA Astrophysics Data System (ADS)

    Tejasvee, Sanjay; Sarangdevot, S. S.

    2010-11-01

    E-Governance is the effective application of information communication and technology (ICT) in the government processes to accomplish safe and reliable information lifecycle management. Lifecycle of the information involves various processes as capturing, preserving, manipulating and delivering information. E-Governance is meant to transform of governance in better manner to the citizens which is transparent, reliable, participatory, and accountable in point of view. The purpose of this paper is to attempt e-governance model, focus on the Service Oriented Computing Architecture (SOCA) that includes combination of information and services provided by the government, innovation, find out the way of optimal service delivery to citizens and implementation in transparent and liable practice. This paper also try to enhance focus on the E-government Service Manager as a essential or key factors service oriented and computing model that provides a dynamically extensible structural design in which all area or branch can bring in innovative services. The heart of this paper examine is an intangible model that enables E-government communication for trade and business, citizen and government and autonomous bodies.

  4. Computer Programming Games and Gender Oriented Cultural Forms

    NASA Astrophysics Data System (ADS)

    AlSulaiman, Sarah Abdulmalik

    I present the design and evaluation of two games designed to help elementary and middle school students learn computer programming concepts. The first game was designed to be "gender neutral", aligning with might be described as a consensus opinion on best practices for computational learning environments. The second game, based on the cultural form of dress up dolls was deliberately designed to appeal to females. I recruited 70 participants in an international two-phase study to investigate the relationship between games, gender, attitudes towards computer programming, and learning. My findings suggest that while the two games were equally effective in terms of learning outcomes, I saw differences in motivation between players of the two games. Specifically, participants who reported a preference for female- oriented games were more motivated to learn about computer programming when they played a game that they perceived as designed for females. In addition, I describe how the two games seemed to encourage different types of social activity between players in a classroom setting. Based on these results, I reflect on the strategy of exclusively designing games and activities as "gender neutral", and suggest that employing cultural forms, including gendered ones, may help create a more productive experience for learners.

  5. Effect of row orientation on energy balance components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solar irradiance is the primary source of energy that is converted into sensible and latent heat fluxes in the soil-plant-atmosphere continuum. The orientation of agricultural crop rows relative to the sun’s zenith angle determines the amount of solar irradiance reaching the plant and soil surfaces...

  6. VRESCo - Vienna Runtime Environment for Service-oriented Computing

    NASA Astrophysics Data System (ADS)

    Hummer, Waldemar; Leitner, Philipp; Michlmayr, Anton; Rosenberg, Florian; Dustdar, Schahram

    Throughout the last years, the Service-Oriented Architecture (SOA) paradigm has been promoted as a means to create loosely coupled distributed applications. In theory, SOAs make use of a service registry, which can be used by providers to publish their services and by clients to discover these services in order to execute them. However, service registries such as UDDI did not succeed and are rarely used today. In practice, the binding often takes place at design time (for instance by generating client-side stubs), which leads to a tighter coupling between service endpoints. Alternative solutions using dynamic invocations often lack a data abstraction and require developers to construct messages on XML or SOAP level. In this paper we present VRESCo, the Vienna Runtime Environment for Service-oriented Computing, which addresses several distinct issues that are currently prevalent in Service-Oriented Architecture (SOA) research and practice. VRESCo reemphasizes the importance of registries to support dynamic selection, binding and invocation of services. Service providers publish their services and clients retrieve the data stored in the registry using a specialized query language. The data model distinguishes between abstract features and concrete service implementations, which enables grouping of services according to their functionality. An abstracted message format allows VRESCo to mediate between services which provide the same feature but use a different message syntax. Furthermore, VRESCo allows for explicit versioning of services. In addition to functional entities, the VRESCo service metadata model contains QoS (Quality of Service) attributes. Clients can be configured to dynamically rebind to different service instances based on the QoS data. The paper presents an illustrative scenario taken from the telecommunications domain, which serves as the basis for the discussion of the features of VRESCo.

  7. Computing support for High Energy Physics

    SciTech Connect

    Avery, P.; Yelton, J.

    1996-12-01

    This computing proposal (Task S) is submitted separately but in support of the High Energy Experiment (CLEO, Fermilab, CMS) and Theory tasks. The authors have built a very strong computing base at Florida over the past 8 years. In fact, computing has been one of the main contributions to their experimental collaborations, involving not just computing capacity for running Monte Carlos and data reduction, but participation in many computing initiatives, industrial partnerships, computing committees and collaborations. These facts justify the submission of a separate computing proposal.

  8. Our U.S. Energy Future, Student Guide. Computer Technology Program Environmental Education Units.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    This is the student guide in a set of five computer-oriented environmental/energy education units. Contents are organized into the following parts or lessons: (1) Introduction to the U.S. Energy Future; (2) Description of the "FUTURE" programs; (3) Effects of "FUTURE" decisions; and (4) Exercises on the U.S. energy future. This…

  9. Hysteresis model and statistical interpretation of energy losses in non-oriented steels

    NASA Astrophysics Data System (ADS)

    Mănescu (Păltânea), Veronica; Păltânea, Gheorghe; Gavrilă, Horia

    2016-04-01

    In this paper the hysteresis energy losses in two non-oriented industrial steels (M400-65A and M800-65A) were determined, by means of an efficient classical Preisach model, which is based on the Pescetti-Biorci method for the identification of the Preisach density. The excess and the total energy losses were also determined, using a statistical framework, based on magnetic object theory. The hysteresis energy losses, in a non-oriented steel alloy, depend on the peak magnetic polarization and they can be computed using a Preisach model, due to the fact that in these materials there is a direct link between the elementary rectangular loops and the discontinuous character of the magnetization process (Barkhausen jumps). To determine the Preisach density it was necessary to measure the normal magnetization curve and the saturation hysteresis cycle. A system of equations was deduced and the Preisach density was calculated for a magnetic polarization of 1.5 T; then the hysteresis cycle was reconstructed. Using the same pattern for the Preisach distribution, it was computed the hysteresis cycle for 1 T. The classical losses were calculated using a well known formula and the excess energy losses were determined by means of the magnetic object theory. The total energy losses were mathematically reconstructed and compared with those, measured experimentally.

  10. User's Guide and Orientation to Canned Computer Programs.

    ERIC Educational Resources Information Center

    Kretke, George L.; Hopkins, Kenneth D.

    This handbook is for the student with little or no previous experience with computer utilization for data processing. Sample problems to be run on the computer are included. It gives: (1) an overview of the sequence of steps from obtaining data to receiving computer output, (2) a guide to common computer packages, (3) an illustration of the use of…

  11. Computing in high-energy physics

    DOE PAGES

    Mount, Richard P.

    2016-05-31

    I present a very personalized journey through more than three decades of computing for experimental high-energy physics, pointing out the enduring lessons that I learned. This is followed by a vision of how the computing environment will evolve in the coming ten years and the technical challenges that this will bring. I then address the scale and cost of high-energy physics software and examine the many current and future challenges, particularly those of management, funding and software-lifecycle management. Lastly, I describe recent developments aimed at improving the overall coherence of high-energy physics software.

  12. Breadth-Oriented Outcomes Assessment in Computer Science.

    ERIC Educational Resources Information Center

    Cordes, David; And Others

    Little work has been done regarding the overall assessment of quality of computer science graduates at the undergraduate level. This paper reports on a pilot study at the University of Alabama of a prototype computer science outcomes assessment designed to evaluate the breadth of knowledge of computer science seniors. The instrument evaluated two…

  13. An Introductory Course on Service-Oriented Computing for High Schools

    ERIC Educational Resources Information Center

    Tsai, W. T.; Chen, Yinong; Cheng, Calvin; Sun, Xin; Bitter, Gary; White, Mary

    2008-01-01

    Service-Oriented Computing (SOC) is a new computing paradigm that has been adopted by major computer companies as well as government agencies such as the Department of Defense for mission-critical applications. SOC is being used for developing Web and electronic business applications, as well as robotics, gaming, and scientific applications. Yet,…

  14. Evaluating Computer-Generated Domain-Oriented Vocabularies.

    ERIC Educational Resources Information Center

    Damerau, Fred J.

    1990-01-01

    Discusses methods for automatically compiling domain-oriented vocabularies in natural language systems and describes techniques for evaluating the quality of the resulting word lists. A study is described that used subject headings from Grolier's Encyclopedia and the United Press International newswire, and filters for removing high frequency…

  15. Fast quantum computation at arbitrarily low energy

    NASA Astrophysics Data System (ADS)

    Jordan, Stephen P.

    2017-03-01

    One version of the energy-time uncertainty principle states that the minimum time T⊥ for a quantum system to evolve from a given state to any orthogonal state is h /(4 Δ E ) , where Δ E is the energy uncertainty. A related bound called the Margolus-Levitin theorem states that T⊥≥h /(2 ) , where is the expectation value of energy and the ground energy is taken to be zero. Many subsequent works have interpreted T⊥ as defining a minimal time for an elementary computational operation and correspondingly a fundamental limit on clock speed determined by a system's energy. Here we present local time-independent Hamiltonians in which computational clock speed becomes arbitrarily large relative to and Δ E as the number of computational steps goes to infinity. We argue that energy considerations alone are not sufficient to obtain an upper bound on computational speed, and that additional physical assumptions such as limits to information density and information transmission speed are necessary to obtain such a bound.

  16. Computer Science Majors: Sex Role Orientation, Academic Achievement, and Social Cognitive Factors

    ERIC Educational Resources Information Center

    Brown, Chris; Garavalia, Linda S.; Fritts, Mary Lou Hines; Olson, Elizabeth A.

    2006-01-01

    This study examined the sex role orientations endorsed by 188 male and female students majoring in computer science, a male-dominated college degree program. The relations among sex role orientation and academic achievement and social cognitive factors influential in career decision-making self-efficacy were explored. Findings revealed that…

  17. Oral Interaction around Computers in the Project-Oriented CALL Classroom

    ERIC Educational Resources Information Center

    Jeon-Ellis, Gumock; Debski, Robert; Wigglesworth, Gillian

    2005-01-01

    Language teachers need to provide students with a context for genuine communication (Sullivan, 2000). Project-oriented computer-assisted language learning (PrOCALL) attempts to achieve this by orienting learners towards tasks, which encourages them to communicate in the target language while working towards completion of a project (Debski, 2000).…

  18. Piezoelectric energy harvesting computer controlled test bench

    NASA Astrophysics Data System (ADS)

    Vázquez-Rodriguez, M.; Jiménez, F. J.; de Frutos, J.; Alonso, D.

    2016-09-01

    In this paper a new computer controlled (C.C.) laboratory test bench is presented. The patented test bench is made up of a C.C. road traffic simulator, C.C. electronic hardware involved in automating measurements, and test bench control software interface programmed in LabVIEW™. Our research is focused on characterizing electronic energy harvesting piezoelectric-based elements in road traffic environments to extract (or "harvest") maximum power. In mechanical to electrical energy conversion, mechanical impacts or vibrational behavior are commonly used, and several major problems need to be solved to perform optimal harvesting systems including, but no limited to, primary energy source modeling, energy conversion, and energy storage. It is described a novel C.C. test bench that obtains, in an accurate and automatized process, a generalized linear equivalent electrical model of piezoelectric elements and piezoelectric based energy store harvesting circuits in order to scale energy generation with multiple devices integrated in different topologies.

  19. Piezoelectric energy harvesting computer controlled test bench.

    PubMed

    Vázquez-Rodriguez, M; Jiménez, F J; de Frutos, J; Alonso, D

    2016-09-01

    In this paper a new computer controlled (C.C.) laboratory test bench is presented. The patented test bench is made up of a C.C. road traffic simulator, C.C. electronic hardware involved in automating measurements, and test bench control software interface programmed in LabVIEW™. Our research is focused on characterizing electronic energy harvesting piezoelectric-based elements in road traffic environments to extract (or "harvest") maximum power. In mechanical to electrical energy conversion, mechanical impacts or vibrational behavior are commonly used, and several major problems need to be solved to perform optimal harvesting systems including, but no limited to, primary energy source modeling, energy conversion, and energy storage. It is described a novel C.C. test bench that obtains, in an accurate and automatized process, a generalized linear equivalent electrical model of piezoelectric elements and piezoelectric based energy store harvesting circuits in order to scale energy generation with multiple devices integrated in different topologies.

  20. ICT Oriented toward Nyaya: Community Computing in India's Slums

    ERIC Educational Resources Information Center

    Byker, Erik J.

    2014-01-01

    In many schools across India, access to information and communication technology (ICT) is still a rare privilege. While the Annual Status of Education Report in India (2013) showed a marginal uptick in the amount of computers, the opportunities for children to use those computers have remained stagnant. The lack of access to ICT is especially…

  1. Strategy Generalization across Orientation Tasks: Testing a Computational Cognitive Model

    DTIC Science & Technology

    2008-07-01

    Shepard & Metzler, 1971) and vision (e.g., Tarr & Pinker , 1989). Although orientation tasks are a class of problem that share important features, there...experimental literature (Hirtle & Jonides, 1985; McNamara, 1986; McNamara, Hardy, & Hirtle 1989; Stevens & Coupe, 1978). However, the operations that are...J. (1971). Mental rotation of three dimensional objects. Science, 171, 701–703. Stevens , A., & Coupe, P. (1978). Distortions in judged spatial

  2. Volume dependence of computed grain boundary energy

    SciTech Connect

    Bristowe, P.D.; Brokman, A.

    1980-08-01

    Over the past five years there have been numerous studies of grain boundary structure using the method of computer molecular statics which assume pairwise central potentials for the interatomic interaction. Emphasis is usually placed on relative grain boundary energies but these may be inaccurate due to various, but related, approximations and constraints implicity imposed on the calculation-namely central forces, finite model size, fixed border conditions and volume dependent contributions to the energy of the system. It is the purpose of this work to clarify how these particular properties of the model can affect the computed grain boundary energy and demonstrate instances in which the quoted energy has strictly been inaccurate. The implication of these results, especially on how they affect the method of relaxation and the resulting grain boundary structure is discussed.

  3. The Global Energy Situation on Earth, Student Guide. Computer Technology Program Environmental Education Units.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    This is the student guide in a set of five computer-oriented environmental/energy education units. Contents of this guide are: (1) Introduction to the unit; (2) The "EARTH" program; (3) Exercises; and (4) Sources of information on the energy crisis. This guide supplements a simulation which allows students to analyze different aspects of…

  4. Two-dimensional radiant energy array computers and computing devices

    NASA Technical Reports Server (NTRS)

    Schaefer, D. H.; Strong, J. P., III (Inventor)

    1976-01-01

    Two dimensional digital computers and computer devices operate in parallel on rectangular arrays of digital radiant energy optical signal elements which are arranged in ordered rows and columns. Logic gate devices receive two input arrays and provide an output array having digital states dependent only on the digital states of the signal elements of the two input arrays at corresponding row and column positions. The logic devices include an array of photoconductors responsive to at least one of the input arrays for either selectively accelerating electrons to a phosphor output surface, applying potentials to an electroluminescent output layer, exciting an array of discrete radiant energy sources, or exciting a liquid crystal to influence crystal transparency or reflectivity.

  5. Computational design and optimization of energy materials

    NASA Astrophysics Data System (ADS)

    Chan, Maria

    The use of density functional theory (DFT) to understand and improve energy materials for diverse applications - including energy storage, thermal management, catalysis, and photovoltaics - is widespread. The further step of using high throughput DFT calculations to design materials and has led to an acceleration in materials discovery and development. Due to various limitations in DFT, including accuracy and computational cost, however, it is important to leverage effective models and, in some cases, experimental information to aid the design process. In this talk, I will discuss efforts in design and optimization of energy materials using a combination of effective models, DFT, machine learning, and experimental information.

  6. Computational Study of Orientation-dependent Molecular High Harmonic Spectra

    NASA Astrophysics Data System (ADS)

    Dutoi, Anthony; Seideman, Tamar

    2007-03-01

    Recently, there has been much interest in high harmonic generation (HHG) by aligned molecules [Phys. Rev. A 67 023819, Nature 432 867, Nature 435 470]. During HHG, an electron is ionized and driven back to the cation by a strong, low-frequency field, and radiation is emitted at harmonics of this driving pulse. Because this process is sensitive to the orientation of a molecule, rotational dynamics can be probed on very short time scales. We are working to predict the time-dependent HHG spectra for aligned rotational wavepackets. In conjunction with experiment, these simulations should be valuable for studying the loss of rotational coherence in media such as dense gases. Within the presented formalism, Born-Oppenheimer rotational dynamics are handled exactly, while HHG at any given orientation is estimated by numerical time integration of a one-electron Schr"odinger equation. Propagation outside of the integration grid can be handled using an analytical Volkov propagator at the expense of ignoring the cation field at this distance.

  7. PNNL streamlines energy-guzzling computers

    SciTech Connect

    Beckman, Mary T.; Marquez, Andres

    2008-10-27

    In a room the size of a garage, two rows of six-foot-tall racks holding supercomputer hard drives sit back-to-back. Thin tubes and wires snake off the hard drives, slithering into the corners. Stepping between the rows, a rush of heat whips around you -- the air from fans blowing off processing heat. But walk farther in, between the next racks of hard drives, and the temperature drops noticeably. These drives are being cooled by a non-conducting liquid that runs right over the hardworking processors. The liquid carries the heat away in tubes, saving the air a few degrees. This is the Energy Smart Data Center at Pacific Northwest National Laboratory. The bigger, faster, and meatier supercomputers get, the more energy they consume. PNNL's Andres Marquez has developed this test bed to learn how to train the behemoths in energy efficiency. The work will help supercomputers perform better as well. Processors have to keep cool or suffer from "thermal throttling," says Marquez. "That's the performance threshold where the computer is too hot to run well. That threshold is an industry secret." The center at EMSL, DOE's national scientific user facility at PNNL, harbors several ways of experimenting with energy usage. For example, the room's air conditioning is isolated from the rest of EMSL -- pipes running beneath the floor carry temperature-controlled water through heat exchangers to cooling towers outside. "We can test whether it's more energy efficient to cool directly on the processing chips or out in the water tower," says Marquez. The hard drives feed energy and temperature data to a network server running specially designed software that controls and monitors the data center. To test the center’s limits, the team runs the processors flat out – not only on carefully controlled test programs in the Energy Smart computers, but also on real world software from other EMSL research, such as regional weather forecasting models. Marquez's group is also developing "power

  8. Urban Energy Simulation Based on 3d City Models: a Service-Oriented Approach

    NASA Astrophysics Data System (ADS)

    Wate, P.; Rodrigues, P.; Duminil, E.; Coors, V.

    2016-09-01

    Recent advancements in technology has led to the development of sophisticated software tools revitalizing growth in different domains. Taking advantage of this trend, urban energy domain have developed several compute intensive physical and data driven models. These models are used in various distinct simulation softwares to simulate the whole life-cycle of energy flow in cities from supply, distribution, conversion, storage and consumption. Since some simulation software target a specific energy system, it is necessary to integrate them to predict present and future urban energy needs. However, a key drawback is that, these tools are not compatible with each other as they use custom or propriety formats. Furthermore, they are designed as desktop applications and cannot be easily integrated with third-party tools (open source or commercial). Thereby, missing out on potential model functionalities which are required for sustainable urban energy management. In this paper, we propose a solution based on Service Oriented Architecture (SOA). Our approach relies on open interfaces to offer flexible integration of modelling and computational functionality as loosely coupled distributed services.

  9. Effects of Textual and Animated Orienting Activities and Practice on Learning from Computer-Based Instruction.

    ERIC Educational Resources Information Center

    Rieber, Lloyd P.; Hannafin, Michael J.

    1988-01-01

    Describes study designed to examine the effects of textual and/or computer animated orienting strategies and practice on rule-using and problem-solving skills of elementary school students using computer-assisted instruction. Four different versions of a lesson based on Isaac Newton's Law of Motion are described, and results are analyzed. (28…

  10. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1994-01-01

    Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

  11. Energy consumption of personal computer workstations

    SciTech Connect

    Szydlowski, R.

    1995-12-01

    An important question for consideration is, {open_quotes}Are office equipment plug loads increasing?{close_quotes} Data taken by Pacific Northwest Laboratory (PNL) in May 1990 from the Forrestal Building, the U.S. Department of Energy (DOE) headquarters in Washington, DC, are desegregated by end use including: plug loads, lights, HVAC, large dedicated computers, and elevators. This study was repeated in November 1993, and there was a 3.8%/yr increase in plug loads in a building of approximately 1.75 million sq ft. Subsequent to this measurement, the plug loads were measured continuously by PNL over a 10-month period from November 1993 through September 1994, and the results showed another increase of 3.9%, nearly the same increase as in the previous three years. The energy use of personal computers (PCs) was measured by setting up a mobile outlet module (MOM), a replacement for a strip outlet, with current transformers (CTs) and potential transformers. The MOM was connected to a set of dataloggers, allowing for the monitoring of up to four PCs at a time. The PCs were plugged in through the MOM to a C180 datalogger, the data collected to a laptop, and the individual 24-hour profiles were then reduced to a standard profile. About 200 workstations were studied, including the PC, monitor, printer, modem, external disk drives, and CAD systems with their own peripherals. Also monitored were an additional collection of printers, photocopiers, facsimile machines, and monitor controllers. The end result was a set of profiles for energy use during working hours for five different buildings. There was a wide variation in these profiles from daytime to nighttime, since 16 to 35% of the computers remain on at night. Therefore, the needs for computers left on at night vary, along with the attitudes of people. Another area of energy consumption concern is the type of PC, such as IBM- or Macintosh-compatible, and there are many different kinds of workstations.

  12. An object oriented computer-based patient record reference model.

    PubMed Central

    Doré, L.; Lavril, M.; Jean, F. C.; Degoulet, P.

    1995-01-01

    In the context of health care information systems based on client/server architecture, we address the problem of a common Computer-based Patient Record (CPR). We define it as a collection of faithful observations about patients care, with respect to the free expression of physicians. This CPR model supports several views of the medical data, in order to provide applications with a comprehensive and standardized access to distributed patient data. Finally, we validated our CPR approach as a primary data model server for an application for hypertensive patient management. PMID:8563306

  13. Energy consumption of personal computer workstations

    SciTech Connect

    Szydlowski, R.F.; Chvala, W.D. Jr.

    1994-02-01

    The explosive growth of the information age has had a profound effect on the appearance of today`s office. Although the telephone still remains an important part of the information exchange and processing system within an office, other electronic devices are now considered required equipment within this environment. This office automation equipment includes facsimile machines, photocopiers, personal computers, printers, modems, and other peripherals. A recent estimate of the installed base indicated that 42 million personal computers and 7.3 million printers are in place, consuming 18.2 billion kWh/yr-and this installed base is growing (Luhn 1992). From a productivity standpoint, it can be argued that this equipment greatly improves the efficiency of those working in the office. But of primary concern to energy system designers, building managers, and electric utilities is the fact that this equipment requires electric energy. Although the impact of each incremental piece of equipment is small, installation of thousands of devices per building has resulted in office automation equipment becoming the major contributor to electric consumption and demand growth in commercial buildings. Personal computers and associated equipment are the dominant part of office automation equipment. In some cases, this electric demand growth has caused office buildings electric and cooling systems to overload.

  14. Simple Estimation of Förster Resonance Energy Transfer (FRET) Orientation Factor Distribution in Membranes

    PubMed Central

    Loura, Luís M. S.

    2012-01-01

    Because of its acute sensitivity to distance in the nanometer scale, Förster resonance energy transfer (FRET) has found a large variety of applications in many fields of chemistry, physics, and biology. One important issue regarding the correct usage of FRET is its dependence on the donor-acceptor relative orientation, expressed as the orientation factor κ2. Different donor/acceptor conformations can lead to κ2 values in the 0 ≤ κ2 ≤ 4 range. Because the characteristic distance for FRET, R0, is proportional to (κ2)1/6, uncertainties in the orientation factor are reflected in the quality of information that can be retrieved from a FRET experiment. In most cases, the average value of κ2 corresponding to the dynamic isotropic limit (<κ2> = 2/3) is used for computation of R0 and hence donor-acceptor distances and acceptor concentrations. However, this can lead to significant error in unfavorable cases. This issue is more critical in membrane systems, because of their intrinsically anisotropic nature and their reduced fluidity in comparison to most common solvents. Here, a simple numerical simulation method for estimation of the probability density function of κ2 for membrane-embedded donor and acceptor fluorophores in the dynamic regime is presented. In the simplest form, the proposed procedure uses as input the most probable orientations of the donor and acceptor transition dipoles, obtained by experimental (including linear dichroism) or theoretical (such as molecular dynamics simulation) techniques. Optionally, information about the widths of the donor and/or acceptor angular distributions may be incorporated. The methodology is illustrated for special limiting cases and common membrane FRET pairs. PMID:23203123

  15. Computational materials design for energy applications

    NASA Astrophysics Data System (ADS)

    Ozolins, Vidvuds

    2013-03-01

    General adoption of sustainable energy technologies depends on the discovery and development of new high-performance materials. For instance, waste heat recovery and electricity generation via the solar thermal route require bulk thermoelectrics with a high figure of merit (ZT) and thermal stability at high-temperatures. Energy recovery applications (e.g., regenerative braking) call for the development of rapidly chargeable systems for electrical energy storage, such as electrochemical supercapacitors. Similarly, use of hydrogen as vehicular fuel depends on the ability to store hydrogen at high volumetric and gravimetric densities, as well as on the ability to extract it at ambient temperatures at sufficiently rapid rates. We will discuss how first-principles computational methods based on quantum mechanics and statistical physics can drive the understanding, improvement and prediction of new energy materials. We will cover prediction and experimental verification of new earth-abundant thermoelectrics, transition metal oxides for electrochemical supercapacitors, and kinetics of mass transport in complex metal hydrides. Research has been supported by the US Department of Energy under grant Nos. DE-SC0001342, DE-SC0001054, DE-FG02-07ER46433, and DE-FC36-08GO18136.

  16. Implementing an Affordable High-Performance Computing for Teaching-Oriented Computer Science Curriculum

    ERIC Educational Resources Information Center

    Abuzaghleh, Omar; Goldschmidt, Kathleen; Elleithy, Yasser; Lee, Jeongkyu

    2013-01-01

    With the advances in computing power, high-performance computing (HPC) platforms have had an impact on not only scientific research in advanced organizations but also computer science curriculum in the educational community. For example, multicore programming and parallel systems are highly desired courses in the computer science major. However,…

  17. Effect of Computer-Aided Perspective Drawings on Spatial Orientation and Perspective Drawing Achievement

    ERIC Educational Resources Information Center

    Kurtulus, Aytac

    2011-01-01

    The aim of this study is to investigate the effect of computer-aided Perspective Drawings on eighth grade primary school students' achievement in Spatial Orientation and Perspective Drawing. The study made use of pre-test post-test control group experimental design. The study was conducted with thirty 8th grade students attending a primary school…

  18. Some Specifications for a Computer-Oriented First Course in Electrical Engineering.

    ERIC Educational Resources Information Center

    Commission on Engineering Education, Washington, DC.

    Reported are specifications for a computer-oriented first course in electrical engineering giving new direction to the development of texts and alternative courses of study. Guidelines for choice of topics, a statement of fundamental concepts, pitfalls to avoid, and some sample course outlines are given. The study of circuits through computer…

  19. Computed reconstruction of spatial ammonoid-shell orientation captured from digitized grinding and landmark data

    NASA Astrophysics Data System (ADS)

    Lukeneder, Susanne; Lukeneder, Alexander; Weber, Gerhard W.

    2014-03-01

    The internal orientation of fossil mass occurrences can be exploited as useful source of information about their primary depositional conditions. A series of studies, using different kinds of fossils, especially those with elongated shape (e.g., elongated gastropods), deal with their orientation and the subsequent reconstruction of the depositional conditions (e.g., paleocurrents and transport mechanisms). However, disk-shaped fossils like planispiral cephalopods or gastropods were used, up to now, with caution for interpreting paleocurrents. Moreover, most studies just deal with the topmost surface of such mass occurrences, due to the easier accessibility. Within this study, a new method for three-dimensional reconstruction of the internal structure of a fossil mass occurrence and the subsequent calculation of its spatial shell orientation is established. A 234 million-years-old (Carnian, Triassic) monospecific mass occurrence of the ammonoid Kasimlarceltites krystyni from the Taurus Mountains in Turkey, embedded in limestone, is used for this pilot study. Therefore, a 150×45×140 mm3 block of the ammonoid bearing limestone bed has been grinded to 70 slices, with a distance of 2 mm between each slice. By using a semi-automatic region growing algorithm of the 3D-visualization software Amira, ammonoids of a part of this mass occurrence were segmented and a 3D-model reconstructed. Landmarks, trigonometric and vector-based calculations were used to compute the diameters and the spatial orientation of each ammonoid. The spatial shell orientation was characterized by dip and dip-direction and aperture direction of the longitudinal axis, as well as by dip and azimuth of an imaginary sagittal-plane through each ammonoid. The exact spatial shell orientation was determined for a sample of 675 ammonoids, and their statistical orientation analyzed (i.e., NW/SE). The study combines classical orientation analysis with modern 3D-visualization techniques, and establishes a novel

  20. Method for Statically Checking an Object-oriented Computer Program Module

    NASA Technical Reports Server (NTRS)

    Bierhoff, Kevin M. (Inventor); Aldrich, Jonathan (Inventor)

    2012-01-01

    A method for statically checking an object-oriented computer program module includes the step of identifying objects within a computer program module, at least one of the objects having a plurality of references thereto, possibly from multiple clients. A discipline of permissions is imposed on the objects identified within the computer program module. The permissions enable tracking, from among a discrete set of changeable states, a subset of states each object might be in. A determination is made regarding whether the imposed permissions are violated by a potential reference to any of the identified objects. The results of the determination are output to a user.

  1. Three energy computed tomography with synchrotron radiation

    SciTech Connect

    Menk, R.H.; Thomlinson, W.; Zhong, Z.; Charvet, A.M.; Arfelli, F. |; Chapman, L.

    1997-09-01

    Preliminary experiments for digital subtraction computed tomography (CT) at the K-edge of iodine (33.1 keV) were carried out at SMERF (Synchrotron Medical Research Facility X17B2) at the National Synchrotron Light Source, Brookhaven National Laboratory. The major goal was to evaluate the availability of this kind of imaging for in vivo neurological studies. Using the transvenous coronary angiography system, CT images of various samples and phantoms were taken simultaneously at two slightly different energies bracketing the K-absorption edge of iodine. The logarithmic subtraction of the two images resulted in the contrast enhancement of iodine filled structures. An additional CT image was taken at 99.57 keV (second harmonic of the fundamental wave). The third energy allowed the calculation of absolute iodine, tissue and bone images by means of a matrix inversion. A spatial resolution of 0.8 LP/mm was measured in single energy images and iodine concentrations down to 0.082 mg/ml in a 1/4 diameter detail were visible in the reconstructed subtraction image.

  2. Using object oriented analysis and design to study the SSCL SDC computing system

    SciTech Connect

    Kubena, G.T.; Liao, K. ); Palounek, P.T. ); Day, C. )

    1992-01-01

    A joint study between the Computer Working Group of the SSC Solenoidal Detector Collaboration (SDC) and IBM's Federal Sector Division is focusing on the use of Object Oriented Analysis and Design on the SDC Offline Computing System. One key challenge of the analysis is to discover an efficient way to store and subsequently retrieve raw and reconstructed event data, estimated to be 2 petabytes per year. The Object Oriented approach being used during the analysis and early design is intended to yield a smooth transition to detailed design, prototyping and implementation. The object oriented approach is used as a subprocess of a larger process used by IBM FSD, i.e., a systematic approach to architecting and integrating large complex systems. A description of the overall process and early results are described in a study report produced jointly by the SDC and IBM FSD. The overall process focuses on requirements analysis, operational concept development, problem domain decomposition, development and selection of candidate architectures, automated performance modeling and software architecture. This paper will focus primarily on software architecture. The high level software architecture is viewed as a layered stack consisting of: system services, common physics application framework and unique physics applications. Object oriented analysis is being used to investigate the data storage and management of the event data. An object hierarchy is being created and operational concept scenarios are being used to validate the design. Several database prototypes can then be developed, e.g. object oriented or relational, to prove the concept. The object oriented development is fundamentally different from traditional approaches to design, such as those based exclusively on data flow. Object oriented decomposition more closely models a person's perception of reality, hence the developed system is more understandable, extensible, and maintainable.

  3. Using object oriented analysis and design to study the SSCL SDC computing system

    SciTech Connect

    Kubena, G.T.; Liao, K.; Palounek, P.T.; Day, C.

    1992-02-01

    A joint study between the Computer Working Group of the SSC Solenoidal Detector Collaboration (SDC) and IBM`s Federal Sector Division is focusing on the use of Object Oriented Analysis and Design on the SDC Offline Computing System. One key challenge of the analysis is to discover an efficient way to store and subsequently retrieve raw and reconstructed event data, estimated to be 2 petabytes per year. The Object Oriented approach being used during the analysis and early design is intended to yield a smooth transition to detailed design, prototyping and implementation. The object oriented approach is used as a subprocess of a larger process used by IBM FSD, i.e., a systematic approach to architecting and integrating large complex systems. A description of the overall process and early results are described in a study report produced jointly by the SDC and IBM FSD. The overall process focuses on requirements analysis, operational concept development, problem domain decomposition, development and selection of candidate architectures, automated performance modeling and software architecture. This paper will focus primarily on software architecture. The high level software architecture is viewed as a layered stack consisting of: system services, common physics application framework and unique physics applications. Object oriented analysis is being used to investigate the data storage and management of the event data. An object hierarchy is being created and operational concept scenarios are being used to validate the design. Several database prototypes can then be developed, e.g. object oriented or relational, to prove the concept. The object oriented development is fundamentally different from traditional approaches to design, such as those based exclusively on data flow. Object oriented decomposition more closely models a person`s perception of reality, hence the developed system is more understandable, extensible, and maintainable.

  4. Object-oriented parallel algorithms for computing three-dimensional isopycnal flow

    SciTech Connect

    Concus, Paul; Golub, Gene H.; Sun, Yong

    2000-12-01

    In this paper, we derive an object-oriented parallel algorithm for three-dimensional isopycnal flow simulations. The matrix formulation is central to the algorithm. It enables us to apply an efficient preconditioned conjugate gradient linear solver for the global system of equations, and leads naturally to an object-oriented data structure design and parallel implementation. We discuss as well, in less detail, a similar algorithm based on the reduced system, suitable also for parallel computation. Favorable performances are observed on test problems.

  5. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1988-01-01

    The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

  6. Computer-assisted selection of coplanar beam orientations in intensity-modulated radiation therapy*

    NASA Astrophysics Data System (ADS)

    Pugachev, A.; Xing, L.

    2001-09-01

    In intensity-modulated radiation therapy (IMRT), the incident beam orientations are often determined by a trial and error search. The conventional beam's-eye view (BEV) tool becomes less helpful in IMRT because it is frequently required that beams go through organs at risk (OARs) in order to achieve a compromise between the dosimetric objectives of the planning target volume (PTV) and the OARs. In this paper, we report a beam's-eye view dosimetrics (BEVD) technique to assist in the selection of beam orientations in IMRT. In our method, each beam portal is divided into a grid of beamlets. A score function is introduced to measure the `goodness' of each beamlet at a given gantry angle. The score is determined by the maximum PTV dose deliverable by the beamlet without exceeding the tolerance doses of the OARs and normal tissue located in the path of the beamlet. The overall score of the gantry angle is given by a sum of the scores of all beamlets. For a given patient, the score function is evaluated for each possible beam orientation. The directions with the highest scores are then selected as the candidates for beam placement. This procedure is similar to the BEV approach used in conventional radiation therapy, except that the evaluation by a human is replaced by a score function to take into account the intensity modulation. This technique allows one to select beam orientations without the excessive computing overhead of computer optimization of beam orientation. It also provides useful insight into the problem of selection of beam orientation and is especially valuable for complicated cases where the PTV is surrounded by several sensitive structures and where it is difficult to select a set of `good' beam orientations. Several two-dimensional (2D) model cases were used to test the proposed technique. The plans obtained using the BEVD-selected beam orientations were compared with the plans obtained using equiangular spaced beams. For all the model cases investigated

  7. Orienting the Neighborhood: A Subdivision Energy Analysis Tool; Preprint

    SciTech Connect

    Christensen, C.; Horowitz, S.

    2008-07-01

    This paper describes a new computerized Subdivision Energy Analysis Tool being developed to allow users to interactively design subdivision street layouts while receiving feedback about energy impacts based on user-specified building design variants and availability of roof surfaces for photovoltaic and solar water heating systems.

  8. Computation of far radiation field of an arbitrarily oriented dipole above layered anisotropic half space

    NASA Astrophysics Data System (ADS)

    Cao, Le; Wei, Bing; Ge, De-Biao

    2013-11-01

    Based on the reciprocity theorem, the far field formulation of an arbitrarily oriented electric dipole located at the interface of layered anisotropic half space is deduced. Then, considering the optical path difference of the direct wave and reflected wave, the formulation of the electric dipole located above the interface of layered anisotropic half space is discussed, and the transmission matrix method for computing the reflection coefficients of anisotropic layered half space is introduced in detail. Finally, numerical examples of the field produced by an electric dipole located above layered anisotropic half space are given. The numerical results show that this method can be used in the fast computation of far radiation field of an arbitrarily oriented dipole above layered anisotropic half space.

  9. The Use of Computer Vision Algorithms for Automatic Orientation of Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Markiewicz, Jakub Stefan

    2016-06-01

    The paper presents analysis of the orientation of terrestrial laser scanning (TLS) data. In the proposed data processing methodology, point clouds are considered as panoramic images enriched by the depth map. Computer vision (CV) algorithms are used for orientation, which are applied for testing the correctness of the detection of tie points and time of computations, and for assessing difficulties in their implementation. The BRISK, FASRT, MSER, SIFT, SURF, ASIFT and CenSurE algorithms are used to search for key-points. The source data are point clouds acquired using a Z+F 5006h terrestrial laser scanner on the ruins of Iłża Castle, Poland. Algorithms allowing combination of the photogrammetric and CV approaches are also presented.

  10. Challenges and Opportunities in Using Automatic Differentiation with Object-Oriented Toolkits for Scientific Computing

    SciTech Connect

    Hovland, P; Lee, S; McInnes, L; Norris, B; Smith, B

    2001-04-17

    The increased use of object-oriented toolkits in large-scale scientific simulation presents new opportunities and challenges for the use of automatic (or algorithmic) differentiation (AD) techniques, especially in the context of optimization. Because object-oriented toolkits use well-defined interfaces and data structures, there is potential for simplifying the AD process. Furthermore, derivative computation can be improved by exploiting high-level information about numerical and computational abstractions. However, challenges to the successful use of AD with these toolkits also exist. Among the greatest challenges is balancing the desire to limit the scope of the AD process with the desire to minimize the work required of a user. They discuss their experiences in integrating AD with the PETSc, PVODE, and TAO toolkits and the plans for future research and development in this area.

  11. An Architecture and Supporting Environment of Service-Oriented Computing Based-On Context Awareness

    NASA Astrophysics Data System (ADS)

    Ma, Tianxiao; Wu, Gang; Huang, Jun

    Service-oriented computing (SOC) is emerging to be an important computing paradigm of the next future. Based on context awareness, this paper proposes an architecture of SOC. A definition of the context in open environments such as Internet is given, which is based on ontology. The paper also proposes a supporting environment for the context-aware SOC, which focus on services on-demand composition and context-awareness evolving. A reference implementation of the supporting environment based on OSGi[11] is given at last.

  12. Analysis of resonance energy transfer in model membranes: role of orientational effects.

    PubMed

    Domanov, Yegor A; Gorbenko, Galina P

    2002-10-16

    The model of resonance energy transfer (RET) in membrane systems containing donors randomly distributed over two parallel planes separated by fixed distance and acceptors confined to a single plane is presented. Factors determining energy transfer rate are considered with special attention being given to the contribution from orientational heterogeneity of the donor emission and acceptor absorption transition dipoles. Analysis of simulated data suggests that RET in membranes, as compared to intramolecular energy transfer, is substantially less sensitive to the degree of reorientational freedom of chromophores due to averaging over multiple donor-acceptor pairs. The uncertainties in the distance estimation resulting from the unknown mutual orientation of the donor and acceptor are analyzed.

  13. Nuclear Energy Minicourse, Career Oriented Pre-Technical Physics.

    ERIC Educational Resources Information Center

    Dallas Independent School District, TX.

    This instructional guide, intended for student use, develops the concept of nuclear energy through a series of sequential activities. A technical development of the subject is pursued with examples stressing practical aspects of the concepts. Included in the minicourse are: (1) the rationale, (2) terminal behavioral objectives, (3) enabling…

  14. A Computational Model of In Vitro Angiogenesis based on Extracellular Matrix Fiber Orientation

    PubMed Central

    Edgar, Lowell T.; Sibole, Scott C.; Underwood, Clayton J.; Guilkey, James E.; Weiss, Jeffrey A.

    2012-01-01

    Recent interest in the process of vascularization within the biomedical community has motivated numerous new research efforts focusing on the process of angiogenesis. Although the role of chemical factors during angiogenesis has been well documented, the role of mechanical factors, such as the interaction between angiogenic vessels and the extracellular matrix, remain poorly understood. In vitro methods for studying angiogenesis exist, however measurements available using such techniques often suffer from limited spatial and temporal resolution. For this reason, computational models have been extensively employed to investigate various aspects of angiogenesis. This manuscript outlines the formulation and validation of a simple and robust computational model developed to accurately simulate angiogenesis based on length, branching, and orientation morphometrics collected from vascularized tissue constructs. Excellent agreement was observed between computational and experimental morphometric data over time. Computational predictions of microvessel orientation within an anisotropic matrix correlated well with experimental data. The accuracy of this modeling approach makes it a valuable platform for investigating the role of mechanical interactions during angiogenesis. PMID:22515707

  15. It Takes a Village: Supporting Inquiry- and Equity-Oriented Computer Science Pedagogy through a Professional Learning Community

    ERIC Educational Resources Information Center

    Ryoo, Jean; Goode, Joanna; Margolis, Jane

    2015-01-01

    This article describes the importance that high school computer science teachers place on a teachers' professional learning community designed around an inquiry- and equity-oriented approach for broadening participation in computing. Using grounded theory to analyze four years of teacher surveys and interviews from the Exploring Computer Science…

  16. Turning field size and its effects upon computer-simulated klinotactic orientation.

    PubMed

    Bornbusch, A H

    1984-03-07

    The turning field is defined in the context of klinotaxis as the angular region(s) into which an organism may direct itself at any point in time and space while orienting within a stimulus gradient. The turning field size determines the size distribution of turns an organism can make during klinotaxis. Changes in turning field size affect the efficiency of klinotactic source location as measured by computer simulations of ideal behaviors. The optimal field size lies between 90 and 150 degrees. Turning field size also affects the appearance of search paths made by organisms locating an attractant source. The significance of turning field size is discussed and the described klinotactic model is proposed as a predictive model for orientation research.

  17. An Object-oriented Computer Code for Aircraft Engine Weight Estimation

    NASA Technical Reports Server (NTRS)

    Tong, Michael T.; Naylor, Bret A.

    2008-01-01

    Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA s NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc. that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300- passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case. Keywords: NASA, aircraft engine, weight, object-oriented

  18. Fermilab Central Computing Facility: Energy conservation report and mechanical systems design optimization and cost analysis study

    SciTech Connect

    Krstulovich, S.F.

    1986-11-12

    This report is developed as part of the Fermilab Central Computing Facility Project Title II Design Documentation Update under the provisions of DOE Document 6430.1, Chapter XIII-21, Section 14, paragraph a. As such, it concentrates primarily on HVAC mechanical systems design optimization and cost analysis and should be considered as a supplement to the Title I Design Report date March 1986 wherein energy related issues are discussed pertaining to building envelope and orientation as well as electrical systems design.

  19. Metal-Mediated Affinity and Orientation Specificity in a Computationally Designed Protein Homodimer

    SciTech Connect

    Der, Bryan S.; Machius, Mischa; Miley, Michael J.; Mills, Jeffrey L.; Szyperski, Thomas; Kuhlman, Brian

    2015-10-15

    Computationally designing protein-protein interactions with high affinity and desired orientation is a challenging task. Incorporating metal-binding sites at the target interface may be one approach for increasing affinity and specifying the binding mode, thereby improving robustness of designed interactions for use as tools in basic research as well as in applications from biotechnology to medicine. Here we describe a Rosetta-based approach for the rational design of a protein monomer to form a zinc-mediated, symmetric homodimer. Our metal interface design, named MID1 (NESG target ID OR37), forms a tight dimer in the presence of zinc (MID1-zinc) with a dissociation constant <30 nM. Without zinc the dissociation constant is 4 {micro}M. The crystal structure of MID1-zinc shows good overall agreement with the computational model, but only three out of four designed histidines coordinate zinc. However, a histidine-to-glutamate point mutation resulted in four-coordination of zinc, and the resulting metal binding site and dimer orientation closely matches the computational model (C{alpha} rmsd = 1.4 {angstrom}).

  20. Analytic computation of average energy of neutrons inducing fission

    SciTech Connect

    Clark, Alexander Rich

    2016-08-12

    The objective of this report is to describe how I analytically computed the average energy of neutrons that induce fission in the bare BeRP ball. The motivation of this report is to resolve a discrepancy between the average energy computed via the FMULT and F4/FM cards in MCNP6 by comparison to the analytic results.

  1. Synthesis and energy applications of oriented metal oxide nanoporous films

    NASA Astrophysics Data System (ADS)

    Wu, Qingliu

    This dissertation mainly addresses the synthesis of well-ordered mesoporous titania thin films by dip coating with PEO-PPO-PEO triblock copolymer surfactant template P123. Because P123 is composed of poly(ethylene oxide) [PEO] and poly(propylene oxide) [PPO] blocks, concentrations of ingredients are adjusted to tune the films' wall thickness, pore size and mesophase. Structural changes are consistent with partitioning of species among PEO blocks, PPO blocks, and the PEO/PPO interface. Titanates localize near PEO and increase wall thickness (by 5 nm to 7 nm). Depending on aging temperature, PPG either swells the PPO cores (when it is hydrophobic) or introduces large (>200 nm) voids (when it is hydrophilic but phase separates during heating). 1-butanol localizes at the PEO/PPO interface to favor a 3D hexagonal mesostructure. In another approach, anodizing Ti foils yields vertically aligned titania nanotubes arrays with exceptional stabilities as anodes in lithium ion batteries; they maintain capacities of 130-230 mAhg-1 over 200 cycles. No microstructural changes are induced by battery cycling and good electrical contact is maintained. A diffusion induced stress model suggests that thin-walled nanotubes arrays should be stable under testing conditions, and that ordered hexagonal columnar pore arrays should have both high charge/discharge rates and low stress development. KEY WORDS: materials synthesis, porous, thin film, alternative energy, self-assembly

  2. Quantitatively identical orientation-dependent ionization energy and electron affinity of diindenoperylene

    SciTech Connect

    Han, W. N.; Yonezawa, K.; Makino, R.; Kato, K.; Hinderhofer, A.; Ueno, N.; Kera, S.; Murdey, R.; Shiraishi, R.; Yoshida, H.; Sato, N.

    2013-12-16

    Molecular orientation dependences of the ionization energy (IE) and the electron affinity (EA) of diindenoperylene (DIP) films were studied by using ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy. The molecular orientation was controlled by preparing the DIP films on graphite and SiO{sub 2} substrates. The threshold IE and EA of DIP thin films were determined to be 5.81 and 3.53 eV for the film of flat-lying DIP orientation, respectively, and 5.38 and 3.13 eV for the film of standing DIP orientation, respectively. The result indicates that the IE and EA for the flat-lying film are larger by 0.4 eV and the frontier orbital states shift away from the vacuum level compared to the standing film. This rigid energy shift is ascribed to a surface-electrostatic potential produced by the intramolecular polar bond (>C{sup −}-H{sup +}) for standing orientation and π-electron tailing to vacuum for flat-lying orientation.

  3. Teaching computer interfacing with virtual instruments in an object-oriented language.

    PubMed

    Gulotta, M

    1995-11-01

    LabVIEW is a graphic object-oriented computer language developed to facilitate hardware/software communication. LabVIEW is a complete computer language that can be used like Basic, FORTRAN, or C. In LabVIEW one creates virtual instruments that aesthetically look like real instruments but are controlled by sophisticated computer programs. There are several levels of data acquisition VIs that make it easy to control data flow, and many signal processing and analysis algorithms come with the software as premade VIs. In the classroom, the similarity between virtual and real instruments helps students understand how information is passed between the computer and attached instruments. The software may be used in the absence of hardware so that students can work at home as well as in the classroom. This article demonstrates how LabVIEW can be used to control data flow between computers and instruments, points out important features for signal processing and analysis, and shows how virtual instruments may be used in place of physical instrumentation. Applications of LabVIEW to the teaching laboratory are also discussed, and a plausible course outline is given.

  4. Bringing Advanced Computational Techniques to Energy Research

    SciTech Connect

    Mitchell, Julie C

    2012-11-17

    Please find attached our final technical report for the BACTER Institute award. BACTER was created as a graduate and postdoctoral training program for the advancement of computational biology applied to questions of relevance to bioenergy research.

  5. Office of Fusion Energy computational review

    SciTech Connect

    Cohen, B.I.; Cohen, R.H.; Byers, J.A.

    1996-03-06

    The LLNL MFE Theory and Computations Program supports computational efforts in the following areas: (1) Magnetohydrodynamic equilibrium and stability; (2) Fluid and kinetic edge plasma simulation and modeling; (3) Kinetic and fluid core turbulent transport simulation; (4) Comprehensive tokamak modeling (CORSICA Project) - transport, MHD equilibrium and stability, edge physics, heating, turbulent transport, etc. and (5) Other: ECRH ray tracing, reflectometry, plasma processing. This report discusses algorithm and codes pertaining to these areas.

  6. Mechanisms for Orientation in Low Energy Ion Beam Assisted TiAlN Thin Film Growth

    NASA Astrophysics Data System (ADS)

    Aliotta, Paul V.

    The effects of off-normal ionized vapor bombardment on the orientation and structure of off-normal sputter deposited TiAlN thin films has been investigated with the goal of better understanding the mechanistic pathways in ion beam assisted thin film growth for better control of film properties during deposition. The effects of incident angle for ion bombardment has been investigated as a potential variable during deposition and a comprehensive comparison to current theories of thin film orientation development has been made. It is shown that for low levels of ion energies and rates, films develop (220) orientation with a near amorphous zone 1 (Z1) morphology for low ion incident angles. As the rates and energies of ions increases, (111) orientation and fibrous transition zone (ZT) morphology develops. It is also seen that as the angle of ion bombardment increases the threshold level for rates and energies of ions to cause (111) orientation and ZT morphologies is reduced. This change in orientation and morphology has been shown to change in-situ according to the level of ion bombardment making this transition a potential tool for developing microstructures within thin films. Commonly accepted theories of thin film orientation have been investigated with respect to the development of (111) orientation for low energy ion beam assisted deposition including surface energy reduction, thermal influences, strain energy reduction, ion channeling, and ion damage anisotropy though such mechanisms were not successful in describing the development of (111) orientation. Atomic subplantation, generally regarded as a mechanism for bond formation in diamond-like carbon films, has also been investigated as a potential mechanism for orientation development. By treating the interaction of ions with the depositing film as a collision between ion and surface atom, the transition from (220) to (111) orientation is found to occur when the average energy transferred per atom normal to the

  7. The computational fluid dynamics study of orientation effects of oar-blade.

    PubMed

    Laurent, Alexandra; Rouard, Annie; Mantha, Vishveshwar R; Marinho, Daniel A; Silva, Antonio J; Rouboa, Abel I

    2013-02-01

    The distribution of pressure coefficient formed when the fluid contacts with the kayak oar blade is not been studied extensively. The CFD technique was employed to calculate pressure coefficient distribution on the front and rear faces of oar blade resulting from the numerical resolution equations of the flow around the oar blade in the steady flow conditions (4 m/s) for three angular orientations of the oar (45°, 90°, 135°) with main flow. A three-dimensional (3D) geometric model of oar blade was modeled and the k-ε turbulent model was applied to compute the flow around the oar. The main results reported that, under steady state flow conditions, the drag coefficient (Cd = 2.01 for 4 m/s) at 90° orientation has the similar evolution for the different oar blade orientation to the direction of the flow. This is valid when the orientation of the blade is perpendicular to the direction of the flow. Results indicated that the angle of oar strongly influenced the Cd with maximum values for 90° angle of the oar. Moreover, the distribution of the pressure is different for the internal and external edges depending upon oar angle. Finally, the difference of negative pressure coefficient Cp in the rear side and the positive Cp in the front side, contributes toward propulsive force. The results indicate that CFD can be considered an interesting new approach for pressure coefficient calculation on kayak oar blade. The CFD approach could be a useful tool to evaluate the effects of different blade designs on the oar forces and consequently on the boat propulsion contributing toward the design improvement in future oar models. The dependence of variation of pressure coefficient on the angular position of oar with respect to flow direction gives valuable dynamic information, which can be used during training for kayak competition.

  8. An Object-Oriented Computer Code for Aircraft Engine Weight Estimation

    NASA Technical Reports Server (NTRS)

    Tong, Michael T.; Naylor, Bret A.

    2009-01-01

    Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn Research Center (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA's NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc., that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300-passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case.

  9. Energy--What to Do until the Computer Comes.

    ERIC Educational Resources Information Center

    Johnston, Archie B.

    Drawing from Tallahassee Community College's (TCC's) experiences with energy conservation, this paper offers suggestions for reducing energy costs through computer-controlled systems and other means. After stating the energy problems caused by TCC's multi-zone heating and cooling system, the paper discusses the five-step process by which TCC…

  10. A SUGGESTED CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS. INTERIM REPORT.

    ERIC Educational Resources Information Center

    LESCARBEAU, ROLAND F.; AND OTHERS

    A SUGGESTED POST-SECONDARY CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS WAS DEVELOPED BY A GROUP OF COOPERATING INSTITUTIONS, NOW INCORPORATED AS TECHNICAL EDUCATION CONSORTIUM, INCORPORATED. SPECIFIC NEEDS OF THE COMPUTER AND BUSINESS MACHINE INDUSTRY WERE DETERMINED FROM…

  11. Surface-Energy-Anisotropy-Induced Orientation Effects on RayleighInstabilities in Sapphire

    SciTech Connect

    Santala, Melissa; Glaeser, Andreas M.

    2006-01-01

    Arrays of controlled-geometry, semi-infinite pore channels of systematically varied crystallographic orientation were introduced into undoped m-plane (10{bar 1}0) sapphire substrates using microfabrication techniques and ion-beam etching and subsequently internalized by solid-state diffusion bonding. A series of anneals at 1700 C caused the breakup of these channels into discrete pores via Rayleigh instabilities. In all cases, channels broke up with a characteristic wavelength larger than that expected for a material with isotropic surface energy, reflecting stabilization effects due to surface-energy anisotropy. The breakup wavelength and the time required for complete breakup varied significantly with channel orientation. For most orientations, the instability wavelength for channels of radius R was in the range of 13.2R-25R, and complete breakup occurred within 2-10 h. To first order, the anneal times for complete breakup scale with the square of the breakup wavelength. Channels oriented along a <11{bar 2}0> direction had a wavelength of {approx} 139R, and required 468 h for complete breakup. Cross-sectional analysis of channels oriented along a <11{bar 2}0> direction showed the channel to be completely bounded by stable c(0001), r{l_brace}{bar 1}012{r_brace}, and s{l_brace}10{bar 1}1{r_brace} facets.

  12. Computer simulation allows goal-oriented mechanical ventilation in acute respiratory distress syndrome

    PubMed Central

    Uttman, Leif; Ögren, Helena; Niklason, Lisbet; Drefeldt, Björn; Jonson, Björn

    2007-01-01

    Introduction To prevent further lung damage in patients with acute respiratory distress syndrome (ARDS), it is important to avoid overdistension and cyclic opening and closing of atelectatic alveoli. Previous studies have demonstrated protective effects of using low tidal volume (VT), moderate positive end-expiratory pressure and low airway pressure. Aspiration of dead space (ASPIDS) allows a reduction in VT by eliminating dead space in the tracheal tube and tubing. We hypothesized that, by applying goal-orientated ventilation based on iterative computer simulation, VT can be reduced at high respiratory rate and much further reduced during ASPIDS without compromising gas exchange or causing high airway pressure. Methods ARDS was induced in eight pigs by surfactant perturbation and ventilator-induced lung injury. Ventilator resetting guided by computer simulation was then performed, aiming at minimal VT, plateau pressure 30 cmH2O and isocapnia, first by only increasing respiratory rate and then by using ASPIDS as well. Results VT decreased from 7.2 ± 0.5 ml/kg to 6.6 ± 0.5 ml/kg as respiratory rate increased from 40 to 64 ± 6 breaths/min, and to 4.0 ± 0.4 ml/kg when ASPIDS was used at 80 ± 6 breaths/min. Measured values of arterial carbon dioxide tension were close to predicted values. Without ASPIDS, total positive end-expiratory pressure and plateau pressure were slightly higher than predicted, and with ASPIDS they were lower than predicted. Conclusion In principle, computer simulation may be used in goal-oriented ventilation in ARDS. Further studies are needed to investigate potential benefits and limitations over extended study periods. PMID:17352801

  13. Computational approaches for RNA energy parameter estimation

    PubMed Central

    Andronescu, Mirela; Condon, Anne; Hoos, Holger H.; Mathews, David H.; Murphy, Kevin P.

    2010-01-01

    Methods for efficient and accurate prediction of RNA structure are increasingly valuable, given the current rapid advances in understanding the diverse functions of RNA molecules in the cell. To enhance the accuracy of secondary structure predictions, we developed and refined optimization techniques for the estimation of energy parameters. We build on two previous approaches to RNA free-energy parameter estimation: (1) the Constraint Generation (CG) method, which iteratively generates constraints that enforce known structures to have energies lower than other structures for the same molecule; and (2) the Boltzmann Likelihood (BL) method, which infers a set of RNA free-energy parameters that maximize the conditional likelihood of a set of reference RNA structures. Here, we extend these approaches in two main ways: We propose (1) a max-margin extension of CG, and (2) a novel linear Gaussian Bayesian network that models feature relationships, which effectively makes use of sparse data by sharing statistical strength between parameters. We obtain significant improvements in the accuracy of RNA minimum free-energy pseudoknot-free secondary structure prediction when measured on a comprehensive set of 2518 RNA molecules with reference structures. Our parameters can be used in conjunction with software that predicts RNA secondary structures, RNA hybridization, or ensembles of structures. Our data, software, results, and parameter sets in various formats are freely available at http://www.cs.ubc.ca/labs/beta/Projects/RNA-Params. PMID:20940338

  14. The Energy Computation Paradox and ab initio Protein Folding

    PubMed Central

    Faver, John C.; Benson, Mark L.; He, Xiao; Roberts, Benjamin P.; Wang, Bing; Marshall, Michael S.; Sherrill, C. David; Merz, Kenneth M.

    2011-01-01

    The routine prediction of three-dimensional protein structure from sequence remains a challenge in computational biochemistry. It has been intuited that calculated energies from physics-based scoring functions are able to distinguish native from nonnative folds based on previous performance with small proteins and that conformational sampling is the fundamental bottleneck to successful folding. We demonstrate that as protein size increases, errors in the computed energies become a significant problem. We show, by using error probability density functions, that physics-based scores contain significant systematic and random errors relative to accurate reference energies. These errors propagate throughout an entire protein and distort its energy landscape to such an extent that modern scoring functions should have little chance of success in finding the free energy minima of large proteins. Nonetheless, by understanding errors in physics-based score functions, they can be reduced in a post-hoc manner, improving accuracy in energy computation and fold discrimination. PMID:21541343

  15. Computational Approaches for Understanding Energy Metabolism

    PubMed Central

    Shestov, Alexander A; Barker, Brandon; Gu, Zhenglong; Locasale, Jason W

    2013-01-01

    There has been a surge of interest in understanding the regulation of metabolic networks involved in disease in recent years. Quantitative models are increasingly being used to i nterrogate the metabolic pathways that are contained within this complex disease biology. At the core of this effort is the mathematical modeling of central carbon metabolism involving glycolysis and the citric acid cycle (referred to as energy metabolism). Here we discuss several approaches used to quantitatively model metabolic pathways relating to energy metabolism and discuss their formalisms, successes, and limitations. PMID:23897661

  16. Computer Profile of School Facilities Energy Consumption.

    ERIC Educational Resources Information Center

    Oswalt, Felix E.

    This document outlines a computerized management tool designed to enable building managers to identify energy consumption as related to types and uses of school facilities for the purpose of evaluating and managing the operation, maintenance, modification, and planning of new facilities. Specifically, it is expected that the statistics generated…

  17. Computer Review Can Cut HVAC Energy Use

    ERIC Educational Resources Information Center

    McClure, Charles J. R.

    1974-01-01

    A computerized review of construction bidding documents, usually done by a consulting engineer, can reveal how much money it will cost to operate various alternative types of HVAC equipment over a school's lifetime. The review should include a computerized load calculation, energy systems flow diagram, control system analysis, and a computerized…

  18. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1990-01-01

    The objective was to obtain accurate potential energy surfaces (PES's) for a number of reactions which are important in the H/N/O combustion process. The interest in this is centered around the design of the SCRAM jet engine for the National Aerospace Plane (NASP), which was envisioned as an air-breathing hydrogen-burning vehicle capable of reaching velocities as large as Mach 25. Preliminary studies indicated that the supersonic flow in the combustor region of the scram jet engine required accurate reaction rate data for reactions in the H/N/O system, some of which was not readily available from experiment. The most important class of combustion reactions from the standpoint of the NASP project are radical recombinaton reactions, since these reactions result in most of the heat release in the combustion process. Theoretical characterizations of the potential energy surfaces for these reactions are presented and discussed.

  19. A computational fluid dynamics study of propulsion due to the orientation effects of swimmer's hand.

    PubMed

    Bilinauskaite, Milda; Mantha, Vishveshwar R; Rouboa, Abel I; Ziliukas, Pranas; Silva, António J

    2013-12-01

    The aim of the article is to determine the hydrodynamic characteristics of a swimmer's scanned hand model for various possible combinations of both the angle of attack and the sweepback angle, simulating separate underwater arm stroke phases of front crawl swimming. An actual swimmer's hand with thumb adducted was scanned using an Artec L 3D scanner. ANSYS Fluent code was applied for carrying out steady-state computational fluid dynamics (CFD) analysis. The hand model was positioned in nine different positions corresponding to the swimmer's hand orientations (angle of attack and sweepback angle) and velocities observed during the underwater hand stroke of front crawl. Hydrodynamic forces and coefficients were calculated. Results showed significantly higher drag coefficient values in the pull phase, when compared with previous studies under a steady-state flow condition. The mean value of the ratio of drag and lift coefficients was 2.67 ± 2.3 in underwater phases. The mean value of the ratio of drag and lift forces was 2.73 ± 2.4 in underwater phases. Moreover, hydrodynamic coefficients were not almost constant throughout different flow velocities, and variation was observed for different hand positions corresponding to different stroke phases. The current study suggests that the realistic variation of both the orientation angles influenced higher values of drag, lift and resultant coefficients and forces.

  20. Object-oriented analysis and design: a methodology for modeling the computer-based patient record.

    PubMed

    Egyhazy, C J; Eyestone, S M; Martino, J; Hodgson, C L

    1998-08-01

    The article highlights the importance of an object-oriented analysis and design (OOAD) methodology for the computer-based patient record (CPR) in the military environment. Many OOAD methodologies do not adequately scale up, allow for efficient reuse of their products, or accommodate legacy systems. A methodology that addresses these issues is formulated and used to demonstrate its applicability in a large-scale health care service system. During a period of 6 months, a team of object modelers and domain experts formulated an OOAD methodology tailored to the Department of Defense Military Health System and used it to produce components of an object model for simple order processing. This methodology and the lessons learned during its implementation are described. This approach is necessary to achieve broad interoperability among heterogeneous automated information systems.

  1. Layer-oriented computer-generated holograms for three-dimensional display

    NASA Astrophysics Data System (ADS)

    Cao, Liangcai; Zhao, Yan; Zhang, Hao; Zong, Song; Kong, Dezhao; Jin, Guofan

    2016-09-01

    Depth cues and full-parallax are crucial issues in the calculation of computer-generated holograms (CGHs) for perfect holographic three-dimensional (3-D) display. In order to accelerate the speed of generating CGHs and improve the display quality, three layer-oriented methods are investigated in this paper. The first method is based on angularspectrum, which can provide accurate depth cues. The second method is based on inverse Fresnel diffraction layered holographic stereogram to provide accurate depth information as well as correct occlusion effect. The third method is proposed to generate zoomable 3-D CGHs using layer-based shifted Fresnel diffraction. Numerical simulations and optical experiments have demonstrated that the proposed methods can reconstruct quality 3-D images.

  2. National Energy Research Scientific Computing Center (NERSC): Advancing the frontiers of computational science and technology

    SciTech Connect

    Hules, J.

    1996-11-01

    National Energy Research Scientific Computing Center (NERSC) provides researchers with high-performance computing tools to tackle science`s biggest and most challenging problems. Founded in 1974 by DOE/ER, the Controlled Thermonuclear Research Computer Center was the first unclassified supercomputer center and was the model for those that followed. Over the years the center`s name was changed to the National Magnetic Fusion Energy Computer Center and then to NERSC; it was relocated to LBNL. NERSC, one of the largest unclassified scientific computing resources in the world, is the principal provider of general-purpose computing services to DOE/ER programs: Magnetic Fusion Energy, High Energy and Nuclear Physics, Basic Energy Sciences, Health and Environmental Research, and the Office of Computational and Technology Research. NERSC users are a diverse community located throughout US and in several foreign countries. This brochure describes: the NERSC advantage, its computational resources and services, future technologies, scientific resources, and computational science of scale (interdisciplinary research over a decade or longer; examples: combustion in engines, waste management chemistry, global climate change modeling).

  3. EQUILIBRIUM AND NONEQUILIBRIUM FOUNDATIONS OF FREE ENERGY COMPUTATIONAL METHODS

    SciTech Connect

    C. JARZYNSKI

    2001-03-01

    Statistical mechanics provides a rigorous framework for the numerical estimation of free energy differences in complex systems such as biomolecules. This paper presents a brief review of the statistical mechanical identities underlying a number of techniques for computing free energy differences. Both equilibrium and nonequilibrium methods are covered.

  4. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Levin, Eugene

    1993-01-01

    A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

  5. High energy charged particle optics computer programs

    SciTech Connect

    Carey, D.C.

    1980-09-01

    The computer programs TRANSPORT and TURTLE are described, with special emphasis on recent developments. TRANSPORT is a general matrix evaluation and fitting program. First and second-order transfer matrix elements, including those contributing to time-of-flight differences can be evaluated. Matrix elements of both orders can be fit, separately or simultaneously. Floor coordinates of the beam line may be calculated and included in any fits. Tables of results of misalignments, including effects of bilinear terms can be produced. Fringe fields and pole face rotation angles of bending magnets may be included and also adjusted automatically during the fitting process to produce rectangular magnets. A great variety of output options are available. TURTLE is a Monte Carlo program used to simulate beam line performance. It includes second-order terms and aperture constraints. Replacable subroutines allow an unliminated variety of input beam distributions, scattering algorithms, variables which can be histogrammed, and aperture shapes. Histograms of beam loss can also be produced. Rectangular zero-gradient bending magnets with proper circular trajectories, sagitta offsets, pole face rotation angles, and aperture constraints can be included. The effect of multiple components of quadrupoles up to 40 poles can be evaluated.

  6. Asymmetric energy flow in liquid alkylbenzenes: A computational study

    SciTech Connect

    Leitner, David M.; Pandey, Hari Datt

    2015-10-14

    Ultrafast IR-Raman experiments on substituted benzenes [B. C. Pein et al., J. Phys. Chem. B 117, 10898–10904 (2013)] reveal that energy can flow more efficiently in one direction along a molecule than in others. We carry out a computational study of energy flow in the three alkyl benzenes, toluene, isopropylbenzene, and t-butylbenzene, studied in these experiments, and find an asymmetry in the flow of vibrational energy between the two chemical groups of the molecule due to quantum mechanical vibrational relaxation bottlenecks, which give rise to a preferred direction of energy flow. We compare energy flow computed for all modes of the three alkylbenzenes over the relaxation time into the liquid with energy flow through the subset of modes monitored in the time-resolved Raman experiments and find qualitatively similar results when using the subset compared to all the modes.

  7. Secondary iris recognition method based on local energy-orientation feature

    NASA Astrophysics Data System (ADS)

    Huo, Guang; Liu, Yuanning; Zhu, Xiaodong; Dong, Hongxing

    2015-01-01

    This paper proposes a secondary iris recognition based on local features. The application of the energy-orientation feature (EOF) by two-dimensional Gabor filter to the extraction of the iris goes before the first recognition by the threshold of similarity, which sets the whole iris database into two categories-a correctly recognized class and a class to be recognized. Therefore, the former are accepted and the latter are transformed by histogram to achieve an energy-orientation histogram feature (EOHF), which is followed by a second recognition with the chi-square distance. The experiment has proved that the proposed method, because of its higher correct recognition rate, could be designated as the most efficient and effective among its companion studies in iris recognition algorithms.

  8. Memory device for two-dimensional radiant energy array computers

    NASA Technical Reports Server (NTRS)

    Schaefer, D. H.; Strong, J. P., III (Inventor)

    1977-01-01

    A memory device for two dimensional radiant energy array computers was developed, in which the memory device stores digital information in an input array of radiant energy digital signals that are characterized by ordered rows and columns. The memory device contains a radiant energy logic storing device having a pair of input surface locations for receiving a pair of separate radiant energy digital signal arrays and an output surface location adapted to transmit a radiant energy digital signal array. A regenerative feedback device that couples one of the input surface locations to the output surface location in a manner for causing regenerative feedback is also included

  9. Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation

    NASA Technical Reports Server (NTRS)

    Afjeh, Abdollah A.; Reed, John A.

    2003-01-01

    The following reports are presented on this project:A first year progress report on: Development of a Dynamically Configurable,Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; A second year progress report on: Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; An Extensible, Interchangeable and Sharable Database Model for Improving Multidisciplinary Aircraft Design; Interactive, Secure Web-enabled Aircraft Engine Simulation Using XML Databinding Integration; and Improving the Aircraft Design Process Using Web-based Modeling and Simulation.

  10. Dual-Energy Computed Tomography in Genitourinary Imaging.

    PubMed

    Mileto, Achille; Marin, Daniele

    2017-03-01

    Reignited by innovations in scanner engineering and software design, dual-energy computed tomography (CT) has come back into the clinical radiology arena in the last decade. Possibilities for noninvasive in vivo characterization of genitourinary disease, especially for renal stones and renal masses, have become the pinnacle offerings of dual-energy CT for body imaging in clinical practice. This article renders a state-of-the-art review on clinical applications of dual-energy CT in genitourinary imaging.

  11. Online object oriented Monte Carlo computational tool for the needs of biomedical optics

    PubMed Central

    Doronin, Alexander; Meglinski, Igor

    2011-01-01

    Conceptual engineering design and optimization of laser-based imaging techniques and optical diagnostic systems used in the field of biomedical optics requires a clear understanding of the light-tissue interaction and peculiarities of localization of the detected optical radiation within the medium. The description of photon migration within the turbid tissue-like media is based on the concept of radiative transfer that forms a basis of Monte Carlo (MC) modeling. An opportunity of direct simulation of influence of structural variations of biological tissues on the probing light makes MC a primary tool for biomedical optics and optical engineering. Due to the diversity of optical modalities utilizing different properties of light and mechanisms of light-tissue interactions a new MC code is typically required to be developed for the particular diagnostic application. In current paper introducing an object oriented concept of MC modeling and utilizing modern web applications we present the generalized online computational tool suitable for the major applications in biophotonics. The computation is supported by NVIDEA CUDA Graphics Processing Unit providing acceleration of modeling up to 340 times. PMID:21991540

  12. Computational design of cyclic peptides for the customized oriented immobilization of globular proteins.

    PubMed

    Soler, Miguel A; Rodriguez, Alex; Russo, Anna; Adedeji, Abimbola Feyisara; Dongmo Foumthuim, Cedrix J; Cantarutti, Cristina; Ambrosetti, Elena; Casalis, Loredana; Corazza, Alessandra; Scoles, Giacinto; Marasco, Daniela; Laio, Alessandro; Fortuna, Sara

    2017-01-25

    The oriented immobilization of proteins, key for the development of novel responsive biomaterials, relies on the availability of effective probes. These are generally provided by standard approaches based on in vivo maturation and in vitro selection of antibodies and/or aptamers. These techniques can suffer technical problems when a non-immunogenic epitope needs to be targeted. Here we propose a strategy to circumvent this issue by in silico design. In our method molecular binders, in the form of cyclic peptides, are computationally evolved by stochastically exploring their sequence and structure space to identify high-affinity peptides for a chosen epitope of a target globular protein: here a solvent-exposed site of β2-microglobulin (β2m). Designed sequences were screened by explicit solvent molecular dynamics simulations (MD) followed by experimental validation. Five candidates gave dose-response surface plasmon resonance signals with dissociation constants in the micromolar range. One of them was further analyzed by means of isothermal titration calorimetry, nuclear magnetic resonance, and 250 ns of MD. Atomic-force microscopy imaging showed that this peptide is able to immobilize β2m on a gold surface. In short, we have shown by a variety of experimental techniques that it is possible to capture a protein through an epitope of choice by computational design.

  13. Comparison of Property-Oriented Basis Sets for the Computation of Electronic and Nuclear Relaxation Hyperpolarizabilities.

    PubMed

    Zaleśny, Robert; Baranowska-Łączkowska, Angelika; Medveď, Miroslav; Luis, Josep M

    2015-09-08

    In the present work, we perform an assessment of several property-oriented atomic basis sets in computing (hyper)polarizabilities with a focus on the vibrational contributions. Our analysis encompasses the Pol and LPol-ds basis sets of Sadlej and co-workers, the def2-SVPD and def2-TZVPD basis sets of Rappoport and Furche, and the ORP basis set of Baranowska-Łączkowska and Łączkowski. Additionally, we use the d-aug-cc-pVQZ and aug-cc-pVTZ basis sets of Dunning and co-workers to determine the reference estimates of the investigated electric properties for small- and medium-sized molecules, respectively. We combine these basis sets with ab initio post-Hartree-Fock quantum-chemistry approaches (including the coupled cluster method) to calculate electronic and nuclear relaxation (hyper)polarizabilities of carbon dioxide, formaldehyde, cis-diazene, and a medium-sized Schiff base. The primary finding of our study is that, among all studied property-oriented basis sets, only the def2-TZVPD and ORP basis sets yield nuclear relaxation (hyper)polarizabilities of small molecules with average absolute errors less than 5.5%. A similar accuracy for the nuclear relaxation (hyper)polarizabilites of the studied systems can also be reached using the aug-cc-pVDZ basis set (5.3%), although for more accurate calculations of vibrational contributions, i.e., average absolute errors less than 1%, the aug-cc-pVTZ basis set is recommended. It was also demonstrated that anharmonic contributions to first and second hyperpolarizabilities of a medium-sized Schiff base are particularly difficult to accurately predict at the correlated level using property-oriented basis sets. For instance, the value of the nuclear relaxation first hyperpolarizability computed at the MP2/def2-TZVPD level of theory is roughly 3 times larger than that determined using the aug-cc-pVTZ basis set. We link the failure of the def2-TZVPD basis set with the difficulties in predicting the first-order field

  14. Cray XMT Brings New Energy to High-Performance Computing

    SciTech Connect

    Chavarría-Miranda, Daniel; Gracio, Deborah K.; Marquez, Andres; Nieplocha, Jaroslaw; Scherrer, Chad; Sofia, Heidi J.

    2008-09-30

    The ability to solve our nation’s most challenging problems—whether it’s cleaning up the environment, finding alternative forms of energy or improving public health and safety—requires new scientific discoveries. High performance experimental and computational technologies from the past decade are helping to accelerate these scientific discoveries, but they introduce challenges of their own. The vastly increasing volumes and complexities of experimental and computational data pose significant challenges to traditional high-performance computing (HPC) platforms as terabytes to petabytes of data must be processed and analyzed. And the growing complexity of computer models that incorporate dynamic multiscale and multiphysics phenomena place enormous demands on high-performance computer architectures. Just as these new challenges are arising, the computer architecture world is experiencing a renaissance of innovation. The continuing march of Moore’s law has provided the opportunity to put more functionality on a chip, enabling the achievement of performance in new ways. Power limitations, however, will severely limit future growth in clock rates. The challenge will be to obtain greater utilization via some form of on-chip parallelism, but the complexities of emerging applications will require significant innovation in high-performance architectures. The Cray XMT, the successor to the Tera/Cray MTA, provides an alternative platform for addressing computations that stymie current HPC systems, holding the potential to substantially accelerate data analysis and predictive analytics for many complex challenges in energy, national security and fundamental science that traditional computing cannot do.

  15. Energy level alignment at planar organic heterojunctions: influence of contact doping and molecular orientation.

    PubMed

    Opitz, Andreas

    2017-04-05

    Planar organic heterojunctions are widely used in photovoltaic cells, light-emitting diodes, and bilayer field-effect transistors. The energy level alignment in the devices plays an important role in obtaining the aspired gap arrangement. Additionally, the π-orbital overlap between the involved molecules defines e.g. the charge-separation efficiency in solar cells due to charge-transfer effects. To account for both aspects, direct/inverse photoemission spectroscopy and near edge x-ray absorption fine structure spectroscopy were used to determine the energy level landscape and the molecular orientation at prototypical planar organic heterojunctions. The combined experimental approach results in a comprehensive model for the electronic and morphological characteristics of the interface between the two investigated molecular semiconductors. Following an introduction on heterojunctions used in devices and on energy levels of organic materials, the energy level alignment of planar organic heterojunctions will be discussed. The observed energy landscape is always determined by the individual arrangement between the energy levels of the molecules and the work function of the electrode. This might result in contact doping due to Fermi level pinning at the electrode for donor/acceptor heterojunctions, which also improves the solar cell efficiency. This pinning behaviour can be observed across an unpinned interlayer and results in charge accumulation at the donor/acceptor interface, depending on the transport levels of the respective organic semiconductors. Moreover, molecular orientation will affect the energy levels because of the anisotropy in ionisation energy and electron affinity and is influenced by the structural compatibility of the involved molecules at the heterojunction. High structural compatibility leads to π-orbital stacking between different molecules at a heterojunction, which is of additional interest for photovoltaic active interfaces and for ground

  16. Energy level alignment at planar organic heterojunctions: influence of contact doping and molecular orientation

    NASA Astrophysics Data System (ADS)

    Opitz, Andreas

    2017-04-01

    Planar organic heterojunctions are widely used in photovoltaic cells, light-emitting diodes, and bilayer field-effect transistors. The energy level alignment in the devices plays an important role in obtaining the aspired gap arrangement. Additionally, the π-orbital overlap between the involved molecules defines e.g. the charge-separation efficiency in solar cells due to charge-transfer effects. To account for both aspects, direct/inverse photoemission spectroscopy and near edge x-ray absorption fine structure spectroscopy were used to determine the energy level landscape and the molecular orientation at prototypical planar organic heterojunctions. The combined experimental approach results in a comprehensive model for the electronic and morphological characteristics of the interface between the two investigated molecular semiconductors. Following an introduction on heterojunctions used in devices and on energy levels of organic materials, the energy level alignment of planar organic heterojunctions will be discussed. The observed energy landscape is always determined by the individual arrangement between the energy levels of the molecules and the work function of the electrode. This might result in contact doping due to Fermi level pinning at the electrode for donor/acceptor heterojunctions, which also improves the solar cell efficiency. This pinning behaviour can be observed across an unpinned interlayer and results in charge accumulation at the donor/acceptor interface, depending on the transport levels of the respective organic semiconductors. Moreover, molecular orientation will affect the energy levels because of the anisotropy in ionisation energy and electron affinity and is influenced by the structural compatibility of the involved molecules at the heterojunction. High structural compatibility leads to π-orbital stacking between different molecules at a heterojunction, which is of additional interest for photovoltaic active interfaces and for ground

  17. Computer simulated building energy consumption for verification of energy conservation measures in network facilities

    NASA Technical Reports Server (NTRS)

    Plankey, B.

    1981-01-01

    A computer program called ECPVER (Energy Consumption Program - Verification) was developed to simulate all energy loads for any number of buildings. The program computes simulated daily, monthly, and yearly energy consumption which can be compared with actual meter readings for the same time period. Such comparison can lead to validation of the model under a variety of conditions, which allows it to be used to predict future energy saving due to energy conservation measures. Predicted energy saving can then be compared with actual saving to verify the effectiveness of those energy conservation changes. This verification procedure is planned to be an important advancement in the Deep Space Network Energy Project, which seeks to reduce energy cost and consumption at all DSN Deep Space Stations.

  18. The Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Argumentation Skills

    ERIC Educational Resources Information Center

    Hsu, P. -S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2015-01-01

    The purpose of this quasi-experimental study was to explore how seventh graders in a suburban school in the United States developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application. A total of 54 students (three classes) comprised this treatment…

  19. 'Light and Wires in a Box': The Computer-Oriented Information Age in Support of Effective Higher Education.

    ERIC Educational Resources Information Center

    Lindenau, Suzanne E.

    1984-01-01

    Describes the computer-oriented information age, skills workers will need to keep pace, and how information technologies (microcomputers, communications satellites, and cable systems) can be utilized to support effective higher education. Obstacles to information technology use in education and how schools fail learners if technology is not…

  20. COMPLEAT (Community-Oriented Model for Planning Least-Cost Energy Alternatives and Technologies): A planning tool for publicly owned electric utilities. [Community-Oriented Model for Planning Least-Cost Energy Alternatives and Technologies (Compleat)

    SciTech Connect

    Not Available

    1990-09-01

    COMPLEAT takes its name, as an acronym, from Community-Oriented Model for Planning Least-Cost Energy Alternatives and Technologies. It is an electric utility planning model designed for use principally by publicly owned electric utilities and agencies serving such utilities. As a model, COMPLEAT is significantly more full-featured and complex than called out in APPA's original plan and proposal to DOE. The additional complexity grew out of a series of discussions early in the development schedule, in which it became clear to APPA staff and advisors that the simplicity characterizing the original plan, while highly desirable in terms of utility applications, was not achievable if practical utility problems were to be addressed. The project teams settled on Energy 20/20, an existing model developed by Dr. George Backus of Policy Assessment Associates, as the best candidate for the kinds of modifications and extensions that would be required. The remainder of the project effort was devoted to designing specific input data files, output files, and user screens and to writing and testing the compute programs that would properly implement the desired features around Energy 20/20 as a core program. This report presents in outline form, the features and user interface of COMPLEAT.

  1. Opportunities for discovery: Theory and computation in Basic Energy Sciences

    SciTech Connect

    Harmon, Bruce; Kirby, Kate; McCurdy, C. William

    2005-01-11

    New scientific frontiers, recent advances in theory, and rapid increases in computational capabilities have created compelling opportunities for theory and computation to advance the scientific mission of the Office of Basic Energy Sciences (BES). The prospects for success in the experimental programs of BES will be enhanced by pursuing these opportunities. This report makes the case for an expanded research program in theory and computation in BES. The Subcommittee on Theory and Computation of the Basic Energy Sciences Advisory Committee was charged with identifying current and emerging challenges and opportunities for theoretical research within the scientific mission of BES, paying particular attention to how computing will be employed to enable that research. A primary purpose of the Subcommittee was to identify those investments that are necessary to ensure that theoretical research will have maximum impact in the areas of importance to BES, and to assure that BES researchers will be able to exploit the entire spectrum of computational tools, including leadership class computing facilities. The Subcommittee s Findings and Recommendations are presented in Section VII of this report.

  2. A novel task-oriented optimal design for P300-based brain-computer interfaces.

    PubMed

    Zhou, Zongtan; Yin, Erwei; Liu, Yang; Jiang, Jun; Hu, Dewen

    2014-10-01

    Objective. The number of items of a P300-based brain-computer interface (BCI) should be adjustable in accordance with the requirements of the specific tasks. To address this issue, we propose a novel task-oriented optimal approach aimed at increasing the performance of general P300 BCIs with different numbers of items. Approach. First, we proposed a stimulus presentation with variable dimensions (VD) paradigm as a generalization of the conventional single-character (SC) and row-column (RC) stimulus paradigms. Furthermore, an embedding design approach was employed for any given number of items. Finally, based on the score-P model of each subject, the VD flash pattern was selected by a linear interpolation approach for a certain task. Main results. The results indicate that the optimal BCI design consistently outperforms the conventional approaches, i.e., the SC and RC paradigms. Specifically, there is significant improvement in the practical information transfer rate for a large number of items. Significance. The results suggest that the proposed optimal approach would provide useful guidance in the practical design of general P300-based BCIs.

  3. Towards sustainable infrastructure management: knowledge-based service-oriented computing framework for visual analytics

    NASA Astrophysics Data System (ADS)

    Vatcha, Rashna; Lee, Seok-Won; Murty, Ajeet; Tolone, William; Wang, Xiaoyu; Dou, Wenwen; Chang, Remco; Ribarsky, William; Liu, Wanqiu; Chen, Shen-en; Hauser, Edd

    2009-05-01

    Infrastructure management (and its associated processes) is complex to understand, perform and thus, hard to make efficient and effective informed decisions. The management involves a multi-faceted operation that requires the most robust data fusion, visualization and decision making. In order to protect and build sustainable critical assets, we present our on-going multi-disciplinary large-scale project that establishes the Integrated Remote Sensing and Visualization (IRSV) system with a focus on supporting bridge structure inspection and management. This project involves specific expertise from civil engineers, computer scientists, geographers, and real-world practitioners from industry, local and federal government agencies. IRSV is being designed to accommodate the essential needs from the following aspects: 1) Better understanding and enforcement of complex inspection process that can bridge the gap between evidence gathering and decision making through the implementation of ontological knowledge engineering system; 2) Aggregation, representation and fusion of complex multi-layered heterogeneous data (i.e. infrared imaging, aerial photos and ground-mounted LIDAR etc.) with domain application knowledge to support machine understandable recommendation system; 3) Robust visualization techniques with large-scale analytical and interactive visualizations that support users' decision making; and 4) Integration of these needs through the flexible Service-oriented Architecture (SOA) framework to compose and provide services on-demand. IRSV is expected to serve as a management and data visualization tool for construction deliverable assurance and infrastructure monitoring both periodically (annually, monthly, even daily if needed) as well as after extreme events.

  4. Orientation of bluff body for designing efficient energy harvesters from vortex-induced vibrations

    SciTech Connect

    Dai, H. L.; Abdelkefi, A.; Yang, Y.; Wang, L.

    2016-02-01

    The characteristics and performances of four distinct vortex-induced vibrations (VIVs) piezoelectric energy harvesters are experimentally investigated and compared. The difference between these VIV energy harvesters is the installation of the cylindrical bluff body at the tip of cantilever beam with different orientations (bottom, top, horizontal, and vertical). Experiments show that the synchronization regions of the bottom, top, and horizontal configurations are almost the same at low wind speeds (around 1.5 m/s). The vertical configuration has the highest wind speed for synchronization (around 3.5 m/s) with the largest harvested power, which is explained by its highest natural frequency and the smallest coupled damping. The results lead to the conclusion that to design efficient VIV energy harvesters, the bluff body should be aligned with the beam for low wind speeds (<2 m/s) and perpendicular to the beam at high wind speeds (>2 m/s)

  5. Energy-scalable pulsed mid-IR source using orientation-patterned GaAs.

    PubMed

    French, Douglas; Peterson, Rita; Jovanovic, Igor

    2011-02-15

    Coherent mid-IR sources based on orientation-patterned GaAs (OPGaAs) are of significant interest in diverse scientific, medical, and military applications. The generation of long-wavelength mid-IR beams in OPGaAs using optical parametric oscillation exhibits limitations in the obtainable pulse energy and peak power. The master oscillator power amplifier concept is demonstrated in OPGaAs, by which a mid-IR source based on optical parametric oscillation can be scaled to high energy by amplification of the output of the optical parametric oscillator in an optical parametric amplifier (OPA). A fivefold increase in the pulse energy is obtained using this method by amplifying 3.85μm pulses in an OPGaAs OPA pumped by a Th,Ho:YLF Q-switched laser.

  6. Energy consumption program: A computer model simulating energy loads in buildings

    NASA Technical Reports Server (NTRS)

    Stoller, F. W.; Lansing, F. L.; Chai, V. W.; Higgins, S.

    1978-01-01

    The JPL energy consumption computer program developed as a useful tool in the on-going building modification studies in the DSN energy conservation project is described. The program simulates building heating and cooling loads and computes thermal and electric energy consumption and cost. The accuracy of computations are not sacrificed, however, since the results lie within + or - 10 percent margin compared to those read from energy meters. The program is carefully structured to reduce both user's time and running cost by asking minimum information from the user and reducing many internal time-consuming computational loops. Many unique features were added to handle two-level electronics control rooms not found in any other program.

  7. View southeast of computer controlled energy monitoring system. System replaced ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southeast of computer controlled energy monitoring system. System replaced strip chart recorders and other instruments under the direct observation of the load dispatcher. - Thirtieth Street Station, Load Dispatch Center, Thirtieth & Market Streets, Railroad Station, Amtrak (formerly Pennsylvania Railroad Station), Philadelphia, Philadelphia County, PA

  8. Large Scale Computing and Storage Requirements for High Energy Physics

    SciTech Connect

    Gerber, Richard A.; Wasserman, Harvey

    2010-11-24

    The National Energy Research Scientific Computing Center (NERSC) is the leading scientific computing facility for the Department of Energy's Office of Science, providing high-performance computing (HPC) resources to more than 3,000 researchers working on about 400 projects. NERSC provides large-scale computing resources and, crucially, the support and expertise needed for scientists to make effective use of them. In November 2009, NERSC, DOE's Office of Advanced Scientific Computing Research (ASCR), and DOE's Office of High Energy Physics (HEP) held a workshop to characterize the HPC resources needed at NERSC to support HEP research through the next three to five years. The effort is part of NERSC's legacy of anticipating users needs and deploying resources to meet those demands. The workshop revealed several key points, in addition to achieving its goal of collecting and characterizing computing requirements. The chief findings: (1) Science teams need access to a significant increase in computational resources to meet their research goals; (2) Research teams need to be able to read, write, transfer, store online, archive, analyze, and share huge volumes of data; (3) Science teams need guidance and support to implement their codes on future architectures; and (4) Projects need predictable, rapid turnaround of their computational jobs to meet mission-critical time constraints. This report expands upon these key points and includes others. It also presents a number of case studies as representative of the research conducted within HEP. Workshop participants were asked to codify their requirements in this case study format, summarizing their science goals, methods of solution, current and three-to-five year computing requirements, and software and support needs. Participants were also asked to describe their strategy for computing in the highly parallel, multi-core environment that is expected to dominate HPC architectures over the next few years. The report includes

  9. The effect of orientation dynamics in melittin as antimicrobial peptide in lipid bilayer calculated by free energy method

    NASA Astrophysics Data System (ADS)

    Natasia, Sri R.; Purqon, Acep

    2016-08-01

    Melittin is a widely studied antimicrobial peptide which has gained interest because of its potential in therapeutic use. To perform its antimicrobial function, the melittin prefer to be in a certain state of membrane. In this study, we simulate the melittin in horizontal orientation towards the surface of membrane and in vertical orientation inside transmembrane state. The free energies are then calculated to asses the most favorable orientation, indicating its stable structure, of this peptide interacting with the lipid bilayer. Umbrella sampling with and without pulling simulations is carried out to obtain the sampling windows which used in observing the free energy changes along the reaction coordinate. From our simulations, we found that melittin in vertical orientation in transmembrane state has smaller free energy value than the horizontal one indicating that melittin is more favorable in this configuration. Our results show that melittin undergoes reorientation process from horizontal to vertical to perform its antimicrobial function.

  10. Highly Oriented Graphene Sponge Electrode for Ultra High Energy Density Lithium Ion Hybrid Capacitors.

    PubMed

    Ahn, Wook; Lee, Dong Un; Li, Ge; Feng, Kun; Wang, Xiaolei; Yu, Aiping; Lui, Gregory; Chen, Zhongwei

    2016-09-28

    Highly oriented rGO sponge (HOG) can be easily synthesized as an effective anode for application in high-capacity lithium ion hybrid capacitors. X-ray diffraction and morphological analyses show that successfully exfoliated rGO sponge on average consists of 4.2 graphene sheets, maintaining its three-dimensional structure with highly oriented morphology even after the thermal reduction procedure. Lithium-ion hybrid capacitors (LIC) are fabricated in this study based on a unique cell configuration which completely eliminates the predoping process of lithium ions. The full-cell LIC consisting of AC/HOG-Li configuration has resulted in remarkably high energy densities of 231.7 and 131.9 Wh kg(-1) obtained at 57 W kg(-1) and 2.8 kW kg(-1). This excellent performance is attributed to the lithium ion diffusivity related to the intercalation reaction of AC/HOG-Li which is 3.6 times higher that of AC/CG-Li. This unique cell design and configuration of LIC presented in this study using HOG as an effective anode is an unprecedented example of performance enhancement and improved energy density of LIC through successful increase in cell operation voltage window.

  11. Secure Distributed Detection under Energy Constraint in IoT-Oriented Sensor Networks.

    PubMed

    Zhang, Guomei; Sun, Hao

    2016-12-16

    We study the secure distributed detection problems under energy constraint for IoT-oriented sensor networks. The conventional channel-aware encryption (CAE) is an efficient physical-layer secure distributed detection scheme in light of its energy efficiency, good scalability and robustness over diverse eavesdropping scenarios. However, in the CAE scheme, it remains an open problem of how to optimize the key thresholds for the estimated channel gain, which are used to determine the sensor's reporting action. Moreover, the CAE scheme does not jointly consider the accuracy of local detection results in determining whether to stay dormant for a sensor. To solve these problems, we first analyze the error probability and derive the optimal thresholds in the CAE scheme under a specified energy constraint. These results build a convenient mathematic framework for our further innovative design. Under this framework, we propose a hybrid secure distributed detection scheme. Our proposal can satisfy the energy constraint by keeping some sensors inactive according to the local detection confidence level, which is characterized by likelihood ratio. In the meanwhile, the security is guaranteed through randomly flipping the local decisions forwarded to the fusion center based on the channel amplitude. We further optimize the key parameters of our hybrid scheme, including two local decision thresholds and one channel comparison threshold. Performance evaluation results demonstrate that our hybrid scheme outperforms the CAE under stringent energy constraints, especially in the high signal-to-noise ratio scenario, while the security is still assured.

  12. Object-Oriented Modeling of an Energy Harvesting System Based on Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Nesarajah, Marco; Frey, Georg

    This paper deals with the modeling of an energy harvesting system based on thermoelectric generators (TEG), and the validation of the model by means of a test bench. TEGs are capable to improve the overall energy efficiency of energy systems, e.g. combustion engines or heating systems, by using the remaining waste heat to generate electrical power. Previously, a component-oriented model of the TEG itself was developed in Modelica® language. With this model any TEG can be described and simulated given the material properties and the physical dimension. Now, this model was extended by the surrounding components to a complete model of a thermoelectric energy harvesting system. In addition to the TEG, the model contains the cooling system, the heat source, and the power electronics. To validate the simulation model, a test bench was built and installed on an oil-fired household heating system. The paper reports results of the measurements and discusses the validity of the developed simulation models. Furthermore, the efficiency of the proposed energy harvesting system is derived and possible improvements based on design variations tested in the simulation model are proposed.

  13. Secure Distributed Detection under Energy Constraint in IoT-Oriented Sensor Networks

    PubMed Central

    Zhang, Guomei; Sun, Hao

    2016-01-01

    We study the secure distributed detection problems under energy constraint for IoT-oriented sensor networks. The conventional channel-aware encryption (CAE) is an efficient physical-layer secure distributed detection scheme in light of its energy efficiency, good scalability and robustness over diverse eavesdropping scenarios. However, in the CAE scheme, it remains an open problem of how to optimize the key thresholds for the estimated channel gain, which are used to determine the sensor’s reporting action. Moreover, the CAE scheme does not jointly consider the accuracy of local detection results in determining whether to stay dormant for a sensor. To solve these problems, we first analyze the error probability and derive the optimal thresholds in the CAE scheme under a specified energy constraint. These results build a convenient mathematic framework for our further innovative design. Under this framework, we propose a hybrid secure distributed detection scheme. Our proposal can satisfy the energy constraint by keeping some sensors inactive according to the local detection confidence level, which is characterized by likelihood ratio. In the meanwhile, the security is guaranteed through randomly flipping the local decisions forwarded to the fusion center based on the channel amplitude. We further optimize the key parameters of our hybrid scheme, including two local decision thresholds and one channel comparison threshold. Performance evaluation results demonstrate that our hybrid scheme outperforms the CAE under stringent energy constraints, especially in the high signal-to-noise ratio scenario, while the security is still assured. PMID:27999282

  14. A Crafts-Oriented Approach to Computing in High School: Introducing Computational Concepts, Practices, and Perspectives with Electronic Textiles

    ERIC Educational Resources Information Center

    Kafai, Yasmin B.; Lee, Eunkyoung; Searle, Kristin; Fields, Deborah; Kaplan, Eliot; Lui, Debora

    2014-01-01

    In this article, we examine the use of electronic textiles (e-textiles) for introducing key computational concepts and practices while broadening perceptions about computing. The starting point of our work was the design and implementation of a curriculum module using the LilyPad Arduino in a pre-AP high school computer science class. To…

  15. Requirements for supercomputing in energy research: The transition to massively parallel computing

    SciTech Connect

    Not Available

    1993-02-01

    This report discusses: The emergence of a practical path to TeraFlop computing and beyond; requirements of energy research programs at DOE; implementation: supercomputer production computing environment on massively parallel computers; and implementation: user transition to massively parallel computing.

  16. Sink-oriented Dynamic Location Service Protocol for Mobile Sinks with an Energy Efficient Grid-Based Approach

    PubMed Central

    Jeon, Hyeonjae; Park, Kwangjin; Hwang, Dae-Joon; Choo, Hyunseung

    2009-01-01

    Sensor nodes transmit the sensed information to the sink through wireless sensor networks (WSNs). They have limited power, computational capacities and memory. Portable wireless devices are increasing in popularity. Mechanisms that allow information to be efficiently obtained through mobile WSNs are of significant interest. However, a mobile sink introduces many challenges to data dissemination in large WSNs. For example, it is important to efficiently identify the locations of mobile sinks and disseminate information from multi-source nodes to the multi-mobile sinks. In particular, a stationary dissemination path may no longer be effective in mobile sink applications, due to sink mobility. In this paper, we propose a Sink-oriented Dynamic Location Service (SDLS) approach to handle sink mobility. In SDLS, we propose an Eight-Direction Anchor (EDA) system that acts as a location service server. EDA prevents intensive energy consumption at the border sensor nodes and thus provides energy balancing to all the sensor nodes. Then we propose a Location-based Shortest Relay (LSR) that efficiently forwards (or relays) data from a source node to a sink with minimal delay path. Our results demonstrate that SDLS not only provides an efficient and scalable location service, but also reduces the average data communication overhead in scenarios with multiple and moving sinks and sources. PMID:22573964

  17. Exascale for Energy: The Role of Exascale Computing in Energy Security

    SciTech Connect

    Authors, Various

    2010-07-15

    How will the United States satisfy energy demand in a tightening global energy marketplace while, at the same time, reducing greenhouse gas emissions? Exascale computing -- expected to be available within the next eight to ten years ? may play a crucial role in answering that question by enabling a paradigm shift from test-based to science-based design and engineering. Computational modeling of complete power generation systems and engines, based on scientific first principles, will accelerate the improvement of existing energy technologies and the development of new transformational technologies by pre-selecting the designs most likely to be successful for experimental validation, rather than relying on trial and error. The predictive understanding of complex engineered systems made possible by computational modeling will also reduce the construction and operations costs, optimize performance, and improve safety. Exascale computing will make possible fundamentally new approaches to quantifying the uncertainty of safety and performance engineering. This report discusses potential contributions of exa-scale modeling in four areas of energy production and distribution: nuclear power, combustion, the electrical grid, and renewable sources of energy, which include hydrogen fuel, bioenergy conversion, photovoltaic solar energy, and wind turbines. Examples of current research are taken from projects funded by the U.S. Department of Energy (DOE) Office of Science at universities and national laboratories, with a special focus on research conducted at Lawrence Berkeley National Laboratory.

  18. Energy Proportionality and Performance in Data Parallel Computing Clusters

    SciTech Connect

    Kim, Jinoh; Chou, Jerry; Rotem, Doron

    2011-02-14

    Energy consumption in datacenters has recently become a major concern due to the rising operational costs andscalability issues. Recent solutions to this problem propose the principle of energy proportionality, i.e., the amount of energy consumedby the server nodes must be proportional to the amount of work performed. For data parallelism and fault tolerancepurposes, most common file systems used in MapReduce-type clusters maintain a set of replicas for each data block. A coveringset is a group of nodes that together contain at least one replica of the data blocks needed for performing computing tasks. In thiswork, we develop and analyze algorithms to maintain energy proportionality by discovering a covering set that minimizesenergy consumption while placing the remaining nodes in lowpower standby mode. Our algorithms can also discover coveringsets in heterogeneous computing environments. In order to allow more data parallelism, we generalize our algorithms so that itcan discover k-covering sets, i.e., a set of nodes that contain at least k replicas of the data blocks. Our experimental results showthat we can achieve substantial energy saving without significant performance loss in diverse cluster configurations and workingenvironments.

  19. Massive affordable computing using ARM processors in high energy physics

    NASA Astrophysics Data System (ADS)

    Smith, J. W.; Hamilton, A.

    2015-05-01

    High Performance Computing is relevant in many applications around the world, particularly high energy physics. Experiments such as ATLAS, CMS, ALICE and LHCb generate huge amounts of data which need to be stored and analyzed at server farms located on site at CERN and around the world. Apart from the initial cost of setting up an effective server farm the cost of power consumption and cooling are significant. The proposed solution to reduce costs without losing performance is to make use of ARM® processors found in nearly all smartphones and tablet computers. Their low power consumption, low cost and respectable processing speed makes them an interesting choice for future large scale parallel data processing centers. Benchmarks on the CortexTM-A series of ARM® processors including the HPL and PMBW suites will be presented as well as preliminary results from the PROOF benchmark in the context of high energy physics will be analyzed.

  20. It takes a village: supporting inquiry- and equity-oriented computer science pedagogy through a professional learning community

    NASA Astrophysics Data System (ADS)

    Ryoo, Jean; Goode, Joanna; Margolis, Jane

    2015-10-01

    This article describes the importance that high school computer science teachers place on a teachers' professional learning community designed around an inquiry- and equity-oriented approach for broadening participation in computing. Using grounded theory to analyze four years of teacher surveys and interviews from the Exploring Computer Science (ECS) program in the Los Angeles Unified School District, this article describes how participating in professional development activities purposefully aimed at fostering a teachers' professional learning community helps ECS teachers make the transition to an inquiry-based classroom culture and break professional isolation. This professional learning community also provides experiences that challenge prevalent deficit notions and stereotypes about which students can or cannot excel in computer science.

  1. IR Spectra and Bond Energies Computed Using DFT

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles; Andrews, Lester; Arnold, James (Technical Monitor)

    2000-01-01

    The combination of density functional theory (DFT) frequencies and infrared (IR) intensities and experimental spectra is a very powerful tool in the identification of molecules and ions. The computed and measured isotopic ratios make the identification much more secure than frequencies and intensities alone. This will be illustrated using several examples, such as Mn(CO)n and Mn(CO)n-. The accuracy of DFT metal-ligand bond energies will also be discussed.

  2. Energies and 2'-Hydroxyl Group Orientations of RNA Backbone Conformations. Benchmark CCSD(T)/CBS Database, Electronic Analysis, and Assessment of DFT Methods and MD Simulations.

    PubMed

    Mládek, Arnošt; Banáš, Pavel; Jurečka, Petr; Otyepka, Michal; Zgarbová, Marie; Šponer, Jiří

    2014-01-14

    Sugar-phosphate backbone is an electronically complex molecular segment imparting RNA molecules high flexibility and architectonic heterogeneity necessary for their biological functions. The structural variability of RNA molecules is amplified by the presence of the 2'-hydroxyl group, capable of forming multitude of intra- and intermolecular interactions. Bioinformatics studies based on X-ray structure database revealed that RNA backbone samples at least 46 substates known as rotameric families. The present study provides a comprehensive analysis of RNA backbone conformational preferences and 2'-hydroxyl group orientations. First, we create a benchmark database of estimated CCSD(T)/CBS relative energies of all rotameric families and test performance of dispersion-corrected DFT-D3 methods and molecular mechanics in vacuum and in continuum solvent. The performance of the DFT-D3 methods is in general quite satisfactory. The B-LYP-D3 method provides the best trade-off between accuracy and computational demands. B3-LYP-D3 slightly outperforms the new PW6B95-D3 and MPW1B95-D3 and is the second most accurate density functional of the study. The best agreement with CCSD(T)/CBS is provided by DSD-B-LYP-D3 double-hybrid functional, although its large-scale applications may be limited by high computational costs. Molecular mechanics does not reproduce the fine energy differences between the RNA backbone substates. We also demonstrate that the differences in the magnitude of the hyperconjugation effect do not correlate with the energy ranking of the backbone conformations. Further, we investigated the 2'-hydroxyl group orientation preferences. For all families, we conducted a QM and MM hydroxyl group rigid scan in gas phase and solvent. We then carried out set of explicit solvent MD simulations of folded RNAs and analyze 2'-hydroxyl group orientations of different backbone families in MD. The solvent energy profiles determined primarily by the sugar pucker match well with the

  3. KEYNOTE: Simulation, computation, and the Global Nuclear Energy Partnership

    NASA Astrophysics Data System (ADS)

    Reis, Victor, Dr.

    2006-01-01

    Dr. Victor Reis delivered the keynote talk at the closing session of the conference. The talk was forward looking and focused on the importance of advanced computing for large-scale nuclear energy goals such as Global Nuclear Energy Partnership (GNEP). Dr. Reis discussed the important connections of GNEP to the Scientific Discovery through Advanced Computing (SciDAC) program and the SciDAC research portfolio. In the context of GNEP, Dr. Reis talked about possible fuel leasing configurations, strategies for their implementation, and typical fuel cycle flow sheets. A major portion of the talk addressed lessons learnt from ‘Science Based Stockpile Stewardship’ and the Accelerated Strategic Computing Initiative (ASCI) initiative and how they can provide guidance for advancing GNEP and SciDAC goals. Dr. Reis’s colorful and informative presentation included international proverbs, quotes and comments, in tune with the international flavor that is part of the GNEP philosophy and plan. He concluded with a positive and motivating outlook for peaceful nuclear energy and its potential to solve global problems. An interview with Dr. Reis, addressing some of the above issues, is the cover story of Issue 2 of the SciDAC Review and available at http://www.scidacreview.org This summary of Dr. Reis’s PowerPoint presentation was prepared by Institute of Physics Publishing, the complete PowerPoint version of Dr. Reis’s talk at SciDAC 2006 is given as a multimedia attachment to this summary.

  4. A computational neural model of orientation detection based on multiple guesses: comparison of geometrical and algebraic models.

    PubMed

    Wei, Hui; Ren, Yuan; Wang, Zi Yan

    2013-10-01

    The implementation of Hubel-Wiesel hypothesis that orientation selectivity of a simple cell is based on ordered arrangement of its afferent cells has some difficulties. It requires the receptive fields (RFs) of those ganglion cells (GCs) and LGN cells to be similar in size and sub-structure and highly arranged in a perfect order. It also requires an adequate number of regularly distributed simple cells to match ubiquitous edges. However, the anatomical and electrophysiological evidence is not strong enough to support this geometry-based model. These strict regularities also make the model very uneconomical in both evolution and neural computation. We propose a new neural model based on an algebraic method to estimate orientations. This approach synthesizes the guesses made by multiple GCs or LGN cells and calculates local orientation information subject to a group of constraints. This algebraic model need not obey the constraints of Hubel-Wiesel hypothesis, and is easily implemented with a neural network. By using the idea of a satisfiability problem with constraints, we also prove that the precision and efficiency of this model are mathematically practicable. The proposed model makes clear several major questions which Hubel-Wiesel model does not account for. Image-rebuilding experiments are conducted to check whether this model misses any important boundary in the visual field because of the estimation strategy. This study is significant in terms of explaining the neural mechanism of orientation detection, and finding the circuit structure and computational route in neural networks. For engineering applications, our model can be used in orientation detection and as a simulation platform for cell-to-cell communications to develop bio-inspired eye chips.

  5. Energy and time determine scaling in biological and computer designs.

    PubMed

    Moses, Melanie; Bezerra, George; Edwards, Benjamin; Brown, James; Forrest, Stephanie

    2016-08-19

    Metabolic rate in animals and power consumption in computers are analogous quantities that scale similarly with size. We analyse vascular systems of mammals and on-chip networks of microprocessors, where natural selection and human engineering, respectively, have produced systems that minimize both energy dissipation and delivery times. Using a simple network model that simultaneously minimizes energy and time, our analysis explains empirically observed trends in the scaling of metabolic rate in mammals and power consumption and performance in microprocessors across several orders of magnitude in size. Just as the evolutionary transitions from unicellular to multicellular animals in biology are associated with shifts in metabolic scaling, our model suggests that the scaling of power and performance will change as computer designs transition to decentralized multi-core and distributed cyber-physical systems. More generally, a single energy-time minimization principle may govern the design of many complex systems that process energy, materials and information.This article is part of the themed issue 'The major synthetic evolutionary transitions'.

  6. Efficient free energy calculations of quantum systems through computer simulations

    NASA Astrophysics Data System (ADS)

    Antonelli, Alex; Ramirez, Rafael; Herrero, Carlos; Hernandez, Eduardo

    2009-03-01

    In general, the classical limit is assumed in computer simulation calculations of free energy. This approximation, however, is not justifiable for a class of systems in which quantum contributions for the free energy cannot be neglected. The inclusion of quantum effects is important for the determination of reliable phase diagrams of these systems. In this work, we present a new methodology to compute the free energy of many-body quantum systems [1]. This methodology results from the combination of the path integral formulation of statistical mechanics and efficient non-equilibrium methods to estimate free energy, namely, the adiabatic switching and reversible scaling methods. A quantum Einstein crystal is used as a model to show the accuracy and reliability the methodology. This new method is applied to the calculation of solid-liquid coexistence properties of neon. Our findings indicate that quantum contributions to properties such as, melting point, latent heat of fusion, entropy of fusion, and slope of melting line can be up to 10% of the calculated values using the classical approximation. [1] R. M. Ramirez, C. P. Herrero, A. Antonelli, and E. R. Hernández, Journal of Chemical Physics 129, 064110 (2008)

  7. Social Studies: Application Units. Course II, Teachers. Computer-Oriented Curriculum. REACT (Relevant Educational Applications of Computer Technology).

    ERIC Educational Resources Information Center

    Tecnica Education Corp., San Carlos, CA.

    This book is one of a series in Course II of the Relevant Educational Applications of Computer Technology (REACT) Project. It is designed to point out to teachers two of the major applications of computers in the social sciences: simulation and data analysis. The first section contains a variety of simulation units organized under the following…

  8. Energy current loss instability model on a computer

    NASA Astrophysics Data System (ADS)

    Edighoffer, John A.

    1995-04-01

    The computer program called Energy Stability in a Recirculating Accelerator (ESRA) Free Electron Laser (FEL) has been written to model bunches of particles in longitudinal phase space transversing a recirculating accelerator and the associated rf changes and aperture current losses. This energy-current loss instability was first seen by Los Alamos's FEL group in their energy recovery experiments. This code addresses these stability issues and determines the transport, noise, feedback and other parameters for which these FEL systems are stable or unstable. Two representative systems are modeled, one for the Novosibirisk high power FEL racetrack microtron for photochemical research, the other is the CEBAF proposed UV FEL system. Both of these systems are stable with prudent choices of parameters.

  9. Energy-resolved computed tomography: first experimental results

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2008-10-01

    First experimental results with energy-resolved computed tomography (CT) are reported. The contrast-to-noise ratio (CNR) in CT has been improved with x-ray energy weighting for the first time. Further, x-ray energy weighting improved the CNR in material decomposition CT when applied to CT projections prior to dual-energy subtraction. The existing CT systems use an energy (charge) integrating x-ray detector that provides a signal proportional to the energy of the x-ray photon. Thus, the x-ray photons with lower energies are scored less than those with higher energies. This underestimates contribution of lower energy photons that would provide higher contrast. The highest CNR can be achieved if the x-ray photons are scored by a factor that would increase as the x-ray energy decreases. This could be performed by detecting each x-ray photon separately and measuring its energy. The energy selective CT data could then be saved, and any weighting factor could be applied digitally to a detected x-ray photon. The CT system includes a photon counting detector with linear arrays of pixels made from cadmium zinc telluride (CZT) semiconductor. A cylindrical phantom with 10.2 cm diameter made from tissue-equivalent material was used for CT imaging. The phantom included contrast elements representing calcifications, iodine, adipose and glandular tissue. The x-ray tube voltage was 120 kVp. The energy selective CT data were acquired, and used to generate energy-weighted and material-selective CT images. The energy-weighted and material decomposition CT images were generated using a single CT scan at a fixed x-ray tube voltage. For material decomposition the x-ray spectrum was digitally spilt into low- and high-energy parts and dual-energy subtraction was applied. The x-ray energy weighting resulted in CNR improvement of calcifications and iodine by a factor of 1.40 and 1.63, respectively, as compared to conventional charge integrating CT. The x-ray energy weighting was also applied

  10. Orientation dependences of surface morphologies and energies of iron-gallium alloys

    NASA Astrophysics Data System (ADS)

    Costa, Marcio; Wang, Hui; Hu, Jun; Wu, Ruqian; Na, Suok-Min; Chun, Hyunsuk; Flatau, Alison B.

    2016-05-01

    We investigated the surface energies of several low-index surfaces of the D03-type FeGa alloys (Galfenol), using density functional theory (DFT) simulations and contact angle measurements. DFT calculations predict that (1) the Ga-covered (110) surface of Galfenol is more stable in the Ga-rich condition, while Ga-covered (001) surface of Galfenol become more favorable in Ga-poor condition; and (2) a full Ga overlayer tends to form on top of Galfenol surfaces regardless their orientation, both in agreement with the experimental observation. We also studied Ga segregation in the bcc Fe matrix in order to explore the possibility of Ga precipitation away from Fe. It was found that the Fe-Ga separation is unlikely to occur since Ga diffusion toward the surface is effectively self-stopped once the Ga overlayers form on the facets.

  11. Computed Potential Energy Surfaces and Minimum Energy Pathway for Chemical Reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    Computed potential energy surfaces are often required for computation of such observables as rate constants as a function of temperature, product branching ratios, and other detailed properties. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method with the Dunning correlation consistent basis sets to obtain accurate energetics, gives useful results for a number of chemically important systems. Applications to complex reactions leading to NO and soot formation in hydrocarbon combustion are discussed.

  12. Computational study of the interplay between intermolecular interactions and CO2 orientations in type I hydrates.

    PubMed

    Pérez-Rodríguez, M; Vidal-Vidal, A; Míguez, J M; Blas, F J; Torré, J-P; Piñeiro, M M

    2017-01-25

    Carbon dioxide (CO2) molecules show a rich orientation landscape when they are enclathrated in type I hydrates. Previous studies have described experimentally their preferential orientations, and some theoretical works have explained, but only partially, these experimental results. In the present paper, we use classical molecular dynamics and electronic density functional theory to advance in the theoretical description of CO2 orientations within type I hydrates. Our results are fully compatible with those previously reported, both theoretical and experimental, the geometric shape of the cavities in hydrate being, and therefore, the steric constraints, responsible for some (but not all) preferential angles. In addition, our calculations also show that guest-guest interactions in neighbouring cages are a key factor to explain the remaining experimental angles. Besides the implication concerning equation of state hydrate modeling approximations, the conclusion is that these guest-guest interactions should not be neglected, contrary to the usual practice.

  13. The Role and Design of Computer Studies in a Research-Oriented Translation Program.

    ERIC Educational Resources Information Center

    Meyer, Ingrid

    1991-01-01

    Notes the increasing use of computers by professional translators. Argues that instruction in translation systems should prepare students for both the receiving and production ends of machine translation systems. Discusses considerations for the design of computer translation studies. Includes a course outline from a computer translation seminar.…

  14. Computing at the leading edge: Research in the energy sciences

    SciTech Connect

    Mirin, A.A.; Van Dyke, P.T.

    1994-02-01

    The purpose of this publication is to highlight selected scientific challenges that have been undertaken by the DOE Energy Research community. The high quality of the research reflected in these contributions underscores the growing importance both to the Grand Challenge scientific efforts sponsored by DOE and of the related supporting technologies that the National Energy Research Supercomputer Center (NERSC) and other facilities are able to provide. The continued improvement of the computing resources available to DOE scientists is prerequisite to ensuring their future progress in solving the Grand Challenges. Titles of articles included in this publication include: the numerical tokamak project; static and animated molecular views of a tumorigenic chemical bound to DNA; toward a high-performance climate systems model; modeling molecular processes in the environment; lattice Boltzmann models for flow in porous media; parallel algorithms for modeling superconductors; parallel computing at the Superconducting Super Collider Laboratory; the advanced combustion modeling environment; adaptive methodologies for computational fluid dynamics; lattice simulations of quantum chromodynamics; simulating high-intensity charged-particle beams for the design of high-power accelerators; electronic structure and phase stability of random alloys.

  15. Convolutional networks for fast, energy-efficient neuromorphic computing

    PubMed Central

    Esser, Steven K.; Merolla, Paul A.; Arthur, John V.; Cassidy, Andrew S.; Appuswamy, Rathinakumar; Andreopoulos, Alexander; Berg, David J.; McKinstry, Jeffrey L.; Melano, Timothy; Barch, Davis R.; di Nolfo, Carmelo; Datta, Pallab; Amir, Arnon; Taba, Brian; Flickner, Myron D.; Modha, Dharmendra S.

    2016-01-01

    Deep networks are now able to achieve human-level performance on a broad spectrum of recognition tasks. Independently, neuromorphic computing has now demonstrated unprecedented energy-efficiency through a new chip architecture based on spiking neurons, low precision synapses, and a scalable communication network. Here, we demonstrate that neuromorphic computing, despite its novel architectural primitives, can implement deep convolution networks that (i) approach state-of-the-art classification accuracy across eight standard datasets encompassing vision and speech, (ii) perform inference while preserving the hardware’s underlying energy-efficiency and high throughput, running on the aforementioned datasets at between 1,200 and 2,600 frames/s and using between 25 and 275 mW (effectively >6,000 frames/s per Watt), and (iii) can be specified and trained using backpropagation with the same ease-of-use as contemporary deep learning. This approach allows the algorithmic power of deep learning to be merged with the efficiency of neuromorphic processors, bringing the promise of embedded, intelligent, brain-inspired computing one step closer. PMID:27651489

  16. Convolutional networks for fast, energy-efficient neuromorphic computing.

    PubMed

    Esser, Steven K; Merolla, Paul A; Arthur, John V; Cassidy, Andrew S; Appuswamy, Rathinakumar; Andreopoulos, Alexander; Berg, David J; McKinstry, Jeffrey L; Melano, Timothy; Barch, Davis R; di Nolfo, Carmelo; Datta, Pallab; Amir, Arnon; Taba, Brian; Flickner, Myron D; Modha, Dharmendra S

    2016-10-11

    Deep networks are now able to achieve human-level performance on a broad spectrum of recognition tasks. Independently, neuromorphic computing has now demonstrated unprecedented energy-efficiency through a new chip architecture based on spiking neurons, low precision synapses, and a scalable communication network. Here, we demonstrate that neuromorphic computing, despite its novel architectural primitives, can implement deep convolution networks that (i) approach state-of-the-art classification accuracy across eight standard datasets encompassing vision and speech, (ii) perform inference while preserving the hardware's underlying energy-efficiency and high throughput, running on the aforementioned datasets at between 1,200 and 2,600 frames/s and using between 25 and 275 mW (effectively >6,000 frames/s per Watt), and (iii) can be specified and trained using backpropagation with the same ease-of-use as contemporary deep learning. This approach allows the algorithmic power of deep learning to be merged with the efficiency of neuromorphic processors, bringing the promise of embedded, intelligent, brain-inspired computing one step closer.

  17. Dictionary-based image denoising for dual energy computed tomography

    NASA Astrophysics Data System (ADS)

    Mechlem, Korbinian; Allner, Sebastian; Mei, Kai; Pfeiffer, Franz; Noël, Peter B.

    2016-03-01

    Compared to conventional computed tomography (CT), dual energy CT allows for improved material decomposition by conducting measurements at two distinct energy spectra. Since radiation exposure is a major concern in clinical CT, there is a need for tools to reduce the noise level in images while preserving diagnostic information. One way to achieve this goal is the application of image-based denoising algorithms after an analytical reconstruction has been performed. We have developed a modified dictionary denoising algorithm for dual energy CT aimed at exploiting the high spatial correlation between between images obtained from different energy spectra. Both the low-and high energy image are partitioned into small patches which are subsequently normalized. Combined patches with improved signal-to-noise ratio are formed by a weighted addition of corresponding normalized patches from both images. Assuming that corresponding low-and high energy image patches are related by a linear transformation, the signal in both patches is added coherently while noise is neglected. Conventional dictionary denoising is then performed on the combined patches. Compared to conventional dictionary denoising and bilateral filtering, our algorithm achieved superior performance in terms of qualitative and quantitative image quality measures. We demonstrate, in simulation studies, that this approach can produce 2d-histograms of the high- and low-energy reconstruction which are characterized by significantly improved material features and separation. Moreover, in comparison to other approaches that attempt denoising without simultaneously using both energy signals, superior similarity to the ground truth can be found with our proposed algorithm.

  18. Group-oriented coordination models for distributed client-server computing

    NASA Technical Reports Server (NTRS)

    Adler, Richard M.; Hughes, Craig S.

    1994-01-01

    This paper describes group-oriented control models for distributed client-server interactions. These models transparently coordinate requests for services that involve multiple servers, such as queries across distributed databases. Specific capabilities include: decomposing and replicating client requests; dispatching request subtasks or copies to independent, networked servers; and combining server results into a single response for the client. The control models were implemented by combining request broker and process group technologies with an object-oriented communication middleware tool. The models are illustrated in the context of a distributed operations support application for space-based systems.

  19. Energy summation method for energy loss computation in radial distribution networks

    SciTech Connect

    Taleski, R.; Rajicic, D.

    1996-05-01

    A method for energy loss calculation in radial distribution networks is presented. It is based on the statistical representation of the influence of different load curves in the network upon element power flows and on the oriented ordering of the network elements. Also, the paper proposes the use of different, but constant, voltages at each node, instead of nominal voltage at all nodes. The procedure is very simple, and it involves four steps: element ordering, calculation of second moments, power flow calculation with average loads at nodes, and energy calculation in network elements. The presented results illustrate that the algorithm has advantages over methods that use nominal voltage at each node for accuracy, and advantages over methods that calculate accurate energy losses for speed.

  20. Improving scalability with loop transformations and message aggregation in parallel object-oriented frameworks for scientific computing

    SciTech Connect

    Bassetti, F.; Davis, K.; Quinlan, D.

    1998-09-01

    Application codes reliably achieve performance far less than the advertised capabilities of existing architectures, and this problem is worsening with increasingly-parallel machines. For large-scale numerical applications, stencil operations often impose the great part of the computational cost, and the primary sources of inefficiency are the costs of message passing and poor cache utilization. This paper proposes and demonstrates optimizations for stencil and stencil-like computations for both serial and parallel environments that ameliorate these sources of inefficiency. Achieving scalability, they believe, requires both algorithm design and compile-time support. The optimizations they present are automatable because the stencil-like computations are implemented at a high level of abstraction using object-oriented parallel array class libraries. These optimizations, which are beyond the capabilities of today compilers, may be performed automatically by a preprocessor such as the one they are currently developing.

  1. Department of Energy Mathematical, Information, and Computational Sciences Division: High Performance Computing and Communications Program

    SciTech Connect

    1996-11-01

    This document is intended to serve two purposes. Its first purpose is that of a program status report of the considerable progress that the Department of Energy (DOE) has made since 1993, the time of the last such report (DOE/ER-0536, The DOE Program in HPCC), toward achieving the goals of the High Performance Computing and Communications (HPCC) Program. The second purpose is that of a summary report of the many research programs administered by the Mathematical, Information, and Computational Sciences (MICS) Division of the Office of Energy Research under the auspices of the HPCC Program and to provide, wherever relevant, easy access to pertinent information about MICS-Division activities via universal resource locators (URLs) on the World Wide Web (WWW).

  2. Department of Energy: MICS (Mathematical Information, and Computational Sciences Division). High performance computing and communications program

    SciTech Connect

    1996-06-01

    This document is intended to serve two purposes. Its first purpose is that of a program status report of the considerable progress that the Department of Energy (DOE) has made since 1993, the time of the last such report (DOE/ER-0536, {open_quotes}The DOE Program in HPCC{close_quotes}), toward achieving the goals of the High Performance Computing and Communications (HPCC) Program. The second purpose is that of a summary report of the many research programs administered by the Mathematical, Information, and Computational Sciences (MICS) Division of the Office of Energy Research under the auspices of the HPCC Program and to provide, wherever relevant, easy access to pertinent information about MICS-Division activities via universal resource locators (URLs) on the World Wide Web (WWW). The information pointed to by the URL is updated frequently, and the interested reader is urged to access the WWW for the latest information.

  3. Gestalt Computing and the Study of Content-Oriented User Behavior on the Web

    ERIC Educational Resources Information Center

    Bandari, Roja

    2013-01-01

    Elementary actions online establish an individual's existence on the web and her/his orientation toward different issues. In this sense, actions truly define a user in spaces like online forums and communities and the aggregate of elementary actions shape the atmosphere of these online spaces. This observation, coupled with the unprecedented scale…

  4. A Time Sequence-Oriented Concept Map Approach to Developing Educational Computer Games for History Courses

    ERIC Educational Resources Information Center

    Chu, Hui-Chun; Yang, Kai-Hsiang; Chen, Jing-Hong

    2015-01-01

    Concept maps have been recognized as an effective tool for students to organize their knowledge; however, in history courses, it is important for students to learn and organize historical events according to the time of their occurrence. Therefore, in this study, a time sequence-oriented concept map approach is proposed for developing a game-based…

  5. Identifying and Formulating Teachers' Beliefs and Motivational Orientations for Computer Science Teacher Education

    ERIC Educational Resources Information Center

    Bender, Elena; Schaper, Niclas; Caspersen, Michael E.; Margaritis, Melanie; Hubwieser, Peter

    2016-01-01

    How teachers are able to adapt to a changing environment is essentially dependent on their beliefs and motivational orientations. The development of these aspects in the context of professional competence takes place during teachers' educational phase and professional practice. The overall understanding of professional competence for teaching…

  6. Development of a Dynamically Configurable,Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation

    NASA Technical Reports Server (NTRS)

    Afjeh, Abdollah A.; Reed, John A.

    2003-01-01

    This research is aimed at developing a neiv and advanced simulation framework that will significantly improve the overall efficiency of aerospace systems design and development. This objective will be accomplished through an innovative integration of object-oriented and Web-based technologies ivith both new and proven simulation methodologies. The basic approach involves Ihree major areas of research: Aerospace system and component representation using a hierarchical object-oriented component model which enables the use of multimodels and enforces component interoperability. Collaborative software environment that streamlines the process of developing, sharing and integrating aerospace design and analysis models. . Development of a distributed infrastructure which enables Web-based exchange of models to simplify the collaborative design process, and to support computationally intensive aerospace design and analysis processes. Research for the first year dealt with the design of the basic architecture and supporting infrastructure, an initial implementation of that design, and a demonstration of its application to an example aircraft engine system simulation.

  7. Single-exposure dual-energy computed radiography.

    PubMed

    Stewart, B K; Huang, H K

    1990-01-01

    This paper focuses on analysis and development of a single-exposure dual-energy digital radiographic method using computed radiography (Fuji FCR-101 storage phosphor system). A detector sandwich consisting of storage phosphor imaging plates and an interdetector filter is used. The goal of this process is to provide a simple dual-energy method using typical plane-projection radiographic equipment and techniques. This approach exploits the transparency of the storage phosphor plates, using radiographic information that would be otherwise lost, to provide energy selective information essentially as a by-product of the radiographic examination. In order to effectively make use of the large dynamic range of the storage phosphor imaging plates (10,000:1), a computed radiography image reading mode of fixed analog-to-digital converter gain and variable photomultiplier sensitivity provides image data which can be related to relative incident exposure for export to the decomposition algorithm. Scatter rejection requirements necessitated crossed 12:1 grids for a field size of 36 x 36 cm. Optimal technique parameters obtained from computer simulation through minimization of the aluminum and Plexiglas equivalent image uncertainty under conditions of constant absorbed does resulted as: 100 kVp using a 0.15-mm-thick tin (Sn) interdetector filter for the lung field. This yields a surface exposure of 23 mR and a surface absorbed dose of 0.26 mGy for a 23-cm-thick chest. Clinical application in evaluation of the solitary pulmonary nodule is discussed, along with an image set demonstrating this application.

  8. Computed Potential Energy Surfaces and Minimum Energy Pathways for Chemical Reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. For some dynamics methods, global potential energy surfaces are required. In this case, it is necessary to obtain the energy at a complete sampling of all the possible arrangements of the nuclei, which are energetically accessible, and then a fitting function must be obtained to interpolate between the computed points. In other cases, characterization of the stationary points and the reaction pathway connecting them is sufficient. These properties may be readily obtained using analytical derivative methods. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives usefull results for a number of chemically important systems. The talk will focus on a number of applications including global potential energy surfaces, H + O2, H + N2, O(3p) + H2, and reaction pathways for complex reactions, including reactions leading to NO and soot formation in hydrocarbon combustion.

  9. Computational Modeling of Carbon Nanostructures for Energy Storage Applications

    SciTech Connect

    Feng, Guang; Huang, Jingsong; Qiao, Rui; Sumpter, Bobby G; Meunier, Vincent

    2010-01-01

    We present a theoretical model for electrical double layers formed by ion adsorption in nanoscale carbon pores. In this work a combination of computational methods, including first-principles and classical modeling, are used to explain the onset of an anomalous increase in capacitance for small pores. The study highlights the key role played by pore curvature and nanoconfinement on the capacitance performance. We emphasize the role of modeling in providing a precise understanding of the processes responsible for capacitive energy storage, and how simulations can be used to enhance desired properties and suppress unwanted ones.

  10. PRaVDA: High Energy Physics towards proton Computed Tomography

    NASA Astrophysics Data System (ADS)

    Price, T.

    2016-07-01

    Proton radiotherapy is an increasingly popular modality for treating cancers of the head and neck, and in paediatrics. To maximise the potential of proton radiotherapy it is essential to know the distribution, and more importantly the proton stopping powers, of the body tissues between the proton beam and the tumour. A stopping power map could be measured directly, and uncertainties in the treatment vastly reduce, if the patient was imaged with protons instead of conventional x-rays. Here we outline the application of technologies developed for High Energy Physics to provide clinical-quality proton Computed Tomography, in so reducing range uncertainties and enhancing the treatment of cancer.

  11. Incorporation of the TIP4P water model into a continuum solvent for computing solvation free energy

    NASA Astrophysics Data System (ADS)

    Yang, Pei-Kun

    2014-10-01

    The continuum solvent model is one of the commonly used strategies to compute solvation free energy especially for large-scale conformational transitions such as protein folding or to calculate the binding affinity of protein-protein/ligand interactions. However, the dielectric polarization for computing solvation free energy from the continuum solvent is different than that obtained from molecular dynamic simulations. To mimic the dielectric polarization surrounding a solute in molecular dynamic simulations, the first-shell water molecules was modeled using a charge distribution of TIP4P in a hard sphere; the time-averaged charge distribution from the first-shell water molecules were estimated based on the coordination number of the solute, and the orientation distribution of the first-shell waters and the intermediate water molecules were treated as that of a bulk solvent. Based on this strategy, an equation describing the solvation free energy of ions was derived.

  12. Computational assessment of several hydrogen-free high energy compounds.

    PubMed

    Tan, Bisheng; Huang, Ming; Long, Xinping; Li, Jinshan; Fan, Guijuan

    2016-01-01

    Tetrazino-tetrazine-tetraoxide (TTTO) is an attractive high energy compound, but unfortunately, it is not yet experimentally synthesized so far. Isomerization of TTTO leads to its five isomers, bond-separation energies were empolyed to compare the global stability of six compounds, it is found that isomer 1 has the highest bond-separation energy (1204.6kJ/mol), compared with TTTO (1151.2kJ/mol); thermodynamic properties of six compounds were theoretically calculated, including standard formation enthalpies (solid and gaseous), standard fusion enthalpies, standard vaporation enthalpies, standard sublimation enthalpies, lattice energies and normal melting points, normal boiling points; their detonation performances were also computed, including detonation heat (Q, cal/g), detonation velocity (D, km/s), detonation pressure (P, GPa) and impact sensitivity (h50, cm), compared with TTTO (Q=1311.01J/g, D=9.228km/s, P=40.556GPa, h50=12.7cm), isomer 5 exhibites better detonation performances (Q=1523.74J/g, D=9.389km/s, P=41.329GPa, h50= 28.4cm).

  13. Aiding Design of Wave Energy Converters via Computational Simulations

    NASA Astrophysics Data System (ADS)

    Jebeli Aqdam, Hejar; Ahmadi, Babak; Raessi, Mehdi; Tootkaboni, Mazdak

    2015-11-01

    With the increasing interest in renewable energy sources, wave energy converters will continue to gain attention as a viable alternative to current electricity production methods. It is therefore crucial to develop computational tools for the design and analysis of wave energy converters. A successful design requires balance between the design performance and cost. Here an analytical solution is used for the approximate analysis of interactions between a flap-type wave energy converter (WEC) and waves. The method is verified using other flow solvers and experimental test cases. Then the model is used in conjunction with a powerful heuristic optimization engine, Charged System Search (CSS) to explore the WEC design space. CSS is inspired by charged particles behavior. It searches the design space by considering candidate answers as charged particles and moving them based on the Coulomb's laws of electrostatics and Newton's laws of motion to find the global optimum. Finally the impacts of changes in different design parameters on the power takeout of the superior WEC designs are investigated. National Science Foundation, CBET-1236462.

  14. Object-Oriented Implementation of the Finite-Difference Time-Domain Method in Parallel Computing Environment

    NASA Astrophysics Data System (ADS)

    Chun, Kyungwon; Kim, Huioon; Hong, Hyunpyo; Chung, Youngjoo

    GMES which stands for GIST Maxwell's Equations Solver is a Python package for a Finite-Difference Time-Domain (FDTD) simulation. The FDTD method widely used for electromagnetic simulations is an algorithm to solve the Maxwell's equations. GMES follows Object-Oriented Programming (OOP) paradigm for the good maintainability and usability. With the several optimization techniques along with parallel computing environment, we could make the fast and interactive implementation. Execution speed has been tested in a single host and Beowulf class cluster. GMES is open source and available on the web (http://www.sf.net/projects/gmes).

  15. Computational study to evaluate the birefringence of uniaxially oriented film of cellulose triacetate.

    PubMed

    Hayakawa, Daichi; Ueda, Kazuyoshi

    2015-01-30

    The intrinsic birefringence of a cellulose triacetate (CTA) film is evaluated using the polarizability of the monomer model of the CTA repeating unit, which is calculated using the density functional theory (DFT). Since the CTA monomer is known to have three rotational isomers, referred to as gg, gt, and tg, the intrinsic birefringence of these isomers is evaluated separately. The calculation indicates that the monomer CTA with gg and gt structures shows a negative intrinsic birefringence, whereas the monomer unit with a tg structure shows a positive intrinsic birefringence. By using these values, a model of the uniaxially elongated CTA film is constructed with a molecular dynamics simulation, and the orientation birefringence of the film model was evaluated. The result indicates that the film has negative orientation birefringence and that its value is in good agreement with experimental results.

  16. An Introduction to the Principles of Computer Science: A Reuse-Oriented Philosophy.

    DTIC Science & Technology

    1994-10-27

    The long-term goal of our project is to redesign the software development courses in computer science around a philosophy of software reuse, where...This result has been successfully demonstrated in principle and in practice for the second course in computer science under this project.

  17. Analyzing high energy physics data using database computing: Preliminary report

    NASA Technical Reports Server (NTRS)

    Baden, Andrew; Day, Chris; Grossman, Robert; Lifka, Dave; Lusk, Ewing; May, Edward; Price, Larry

    1991-01-01

    A proof of concept system is described for analyzing high energy physics (HEP) data using data base computing. The system is designed to scale up to the size required for HEP experiments at the Superconducting SuperCollider (SSC) lab. These experiments will require collecting and analyzing approximately 10 to 100 million 'events' per year during proton colliding beam collisions. Each 'event' consists of a set of vectors with a total length of approx. one megabyte. This represents an increase of approx. 2 to 3 orders of magnitude in the amount of data accumulated by present HEP experiments. The system is called the HEPDBC System (High Energy Physics Database Computing System). At present, the Mark 0 HEPDBC System is completed, and can produce analysis of HEP experimental data approx. an order of magnitude faster than current production software on data sets of approx. 1 GB. The Mark 1 HEPDBC System is currently undergoing testing and is designed to analyze data sets 10 to 100 times larger.

  18. Orientational mobility and relaxation spectra of dendrimers: Theory and computer simulation.

    PubMed

    Markelov, Denis A; Lyulin, Sergey V; Gotlib, Yuli Y; Lyulin, Alexey V; Matveev, Vladimir V; Lahderanta, Erkki; Darinskii, Anatolij A

    2009-01-28

    The developed theory of the orientational mobility of individual segments of a perfectly branched dendrimer is used to calculate the relaxation spectrum of a dendrimer. Frequency dependences of NMR relaxation 1/T(1) and of the nuclear Overhauser effect have been theoretically calculated from the Brownian dynamics simulation data. The dendrimer segmental orientational mobility is governed by three main relaxation processes: (i) the rotation of the dendrimer as a whole, (ii) the rotation of the dendrimer's branch originated from a given segment, and (iii) the local reorientation of the segment. The internal orientational mobility of an individual dendrimer segment depends only on the topological distance between this segment and the terminal shell of the dendrimer. Characteristic relaxation times of all processes and their contributions to the segmental mobility have been calculated. The influence of the number of generations and the number of the generation shell on the relaxation times has been studied. The correlation between the characteristic times and the calculated relaxation spectrum of the dendrimer has been established.

  19. Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

    DOE PAGES

    DeWitt, S.; Hahn, N.; Zavadil, K.; ...

    2015-12-30

    Here a new model of electrodeposition and electrodissolution is developed and applied to the evolution of Mg deposits during anode cycling. The model captures Butler-Volmer kinetics, facet evolution, the spatially varying potential in the electrolyte, and the time-dependent electrolyte concentration. The model utilizes a diffuse interface approach, employing the phase field and smoothed boundary methods. Scanning electron microscope (SEM) images of magnesium deposited on a gold substrate show the formation of faceted deposits, often in the form of hexagonal prisms. Orientation-dependent reaction rate coefficients were parameterized using the experimental SEM images. Three-dimensional simulations of the growth of magnesium deposits yieldmore » deposit morphologies consistent with the experimental results. The simulations predict that the deposits become narrower and taller as the current density increases due to the depletion of the electrolyte concentration near the sides of the deposits. Increasing the distance between the deposits leads to increased depletion of the electrolyte surrounding the deposit. Two models relating the orientation-dependence of the deposition and dissolution reactions are presented. Finally, the morphology of the Mg deposit after one deposition-dissolution cycle is significantly different between the two orientation-dependence models, providing testable predictions that suggest the underlying physical mechanisms governing morphology evolution during deposition and dissolution.« less

  20. Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

    SciTech Connect

    DeWitt, S.; Hahn, N.; Zavadil, K.; Thornton, K.

    2015-12-30

    Here a new model of electrodeposition and electrodissolution is developed and applied to the evolution of Mg deposits during anode cycling. The model captures Butler-Volmer kinetics, facet evolution, the spatially varying potential in the electrolyte, and the time-dependent electrolyte concentration. The model utilizes a diffuse interface approach, employing the phase field and smoothed boundary methods. Scanning electron microscope (SEM) images of magnesium deposited on a gold substrate show the formation of faceted deposits, often in the form of hexagonal prisms. Orientation-dependent reaction rate coefficients were parameterized using the experimental SEM images. Three-dimensional simulations of the growth of magnesium deposits yield deposit morphologies consistent with the experimental results. The simulations predict that the deposits become narrower and taller as the current density increases due to the depletion of the electrolyte concentration near the sides of the deposits. Increasing the distance between the deposits leads to increased depletion of the electrolyte surrounding the deposit. Two models relating the orientation-dependence of the deposition and dissolution reactions are presented. Finally, the morphology of the Mg deposit after one deposition-dissolution cycle is significantly different between the two orientation-dependence models, providing testable predictions that suggest the underlying physical mechanisms governing morphology evolution during deposition and dissolution.

  1. Energy Conservation Using Dynamic Voltage Frequency Scaling for Computational Cloud

    PubMed Central

    Florence, A. Paulin; Shanthi, V.; Simon, C. B. Sunil

    2016-01-01

    Cloud computing is a new technology which supports resource sharing on a “Pay as you go” basis around the world. It provides various services such as SaaS, IaaS, and PaaS. Computation is a part of IaaS and the entire computational requests are to be served efficiently with optimal power utilization in the cloud. Recently, various algorithms are developed to reduce power consumption and even Dynamic Voltage and Frequency Scaling (DVFS) scheme is also used in this perspective. In this paper we have devised methodology which analyzes the behavior of the given cloud request and identifies the associated type of algorithm. Once the type of algorithm is identified, using their asymptotic notations, its time complexity is calculated. Using best fit strategy the appropriate host is identified and the incoming job is allocated to the victimized host. Using the measured time complexity the required clock frequency of the host is measured. According to that CPU frequency is scaled up or down using DVFS scheme, enabling energy to be saved up to 55% of total Watts consumption. PMID:27239551

  2. Selected computer system controls at the Energy Information Administration

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of our review of the Energy Information Administration's (EIA) computer system was to evaluate disk and tape information storage and the adequacy of internal controls in the operating system programs. We used a set of computer-assisted audit techniques called CAATS, developed by the US Department of Transportation, Office of Inspector General, in performing the review at the EIA Forrestal Computer Facility. Improved procedures are needed to assure more efficient use of disk space. By transferring data sets from disk to tape, deleting invalid data, releasing unused reserve space and blocking data efficiently, disk space with an estimated value of $1.1 million a year could be recovered for current use. Also, procedures governing the maximum times for storage of information on tapes should be enforced to help ensure that data is not lost. In addition, improved internal controls are needed over granting users system-wide privileges and over authorized program library names to prevent unauthorized access to the system and possible destruction or manipulation of data. Automated Data Processing (ADP) Services Staff officials indicated that software maintenance was not current, due to contractual difficulties with the operating contractor for the Forrestal Facility. Our review confirmed that improvements were needed to help prevent malfunctions of the operating system, which could cause performance degradations, system failures, or loss of either system or user data. Management generally concurred with the recommendations in the report.

  3. Energy Conservation Using Dynamic Voltage Frequency Scaling for Computational Cloud.

    PubMed

    Florence, A Paulin; Shanthi, V; Simon, C B Sunil

    2016-01-01

    Cloud computing is a new technology which supports resource sharing on a "Pay as you go" basis around the world. It provides various services such as SaaS, IaaS, and PaaS. Computation is a part of IaaS and the entire computational requests are to be served efficiently with optimal power utilization in the cloud. Recently, various algorithms are developed to reduce power consumption and even Dynamic Voltage and Frequency Scaling (DVFS) scheme is also used in this perspective. In this paper we have devised methodology which analyzes the behavior of the given cloud request and identifies the associated type of algorithm. Once the type of algorithm is identified, using their asymptotic notations, its time complexity is calculated. Using best fit strategy the appropriate host is identified and the incoming job is allocated to the victimized host. Using the measured time complexity the required clock frequency of the host is measured. According to that CPU frequency is scaled up or down using DVFS scheme, enabling energy to be saved up to 55% of total Watts consumption.

  4. Dielectric energy of orientation in dead and living cells of Schizosaccharomyces pombe. Fitting of experimental results to a theoretical model.

    PubMed Central

    Asencor, F J; Santamaría, C; Iglesias, F J; Domínguez, A

    1993-01-01

    Using the experimental data obtained with killed cells of Schizosaccharomyces pombe (1), we have formulated a theoretical model that is able to predict cell orientation for microorganisms with ellipsoidal or cylindrical shapes as a function of the frequency of the electric field and of the conductivity of the external medium. In this model, comparison of the difference in potential energy for both orientations parallel-perpendicular with the thermal agitation energy allows one to interpret the intervals where these orientations occur. The model implies that the conductivity of the cytoplasm is slightly higher than that of the external medium. This assumption is easy to understand taking into account that not all the intracytoplasmic material is released to the exterior during cell death. PMID:8324197

  5. Parallel Object-Oriented Computation Applied to a Finite Element Problem

    NASA Technical Reports Server (NTRS)

    Weissman, Jon B.; Grimshaw, Andrew S.; Ferraro, Robert

    1993-01-01

    The conventional wisdom in the scientific computing community is that the best way to solve large-scale numerically intensive scientific problems on today's parallel MIMD computers is to use Fortran or C programmed in a data-parallel style using low-level message-passing primitives. This approach inevitably leads to nonportable codes, extensive development time, and restricts parallel programming to the domain of the expert programmer. We believe that these problems are not inherent to parallel computing but are the result of the tools used. We will show that comparable performance can be achieved with little effort if better tools that present higher level abstractions are used.

  6. An Object-Oriented Computer Aided Design Program for Traditional Control Systems Analysis

    DTIC Science & Technology

    1992-12-01

    Butterworth filter templates, Lag- Lead controller design, discrete QFT, nonlinear QFT, etc. before any of them have to worry about porting to the...because the subtraction of small similar numbers on a computer leads to a loss of significant digits. However, a more computer-optimized numerical...use. Time_DataType = Record TF, FFTF TransFunc; ForceFuncType Integer; DataFileName String; DataFile File of Extended; First, Final, Delta extended

  7. Computational efficiences for calculating rare earth f^n energies

    NASA Astrophysics Data System (ADS)

    Beck, Donald R.

    2009-05-01

    RecentlyootnotetextD. R. Beck and E. J. Domeier, Can. J. Phys. Walter Johnson issue, Jan. 2009., we have used new computational strategies to obtain wavefunctions and energies for Gd IV 4f^7 and 4f^65d levels. Here we extend one of these techniques to allow efficent inclusion of 4f^2 pair correlation effects using radial pair energies obtained from much simpler calculationsootnotetexte.g. K. Jankowski et al., Int. J. Quant. Chem. XXVII, 665 (1985). and angular factors which can be simply computedootnotetextD. R. Beck and C. A. Nicolaides, Excited States in Quantum Chemistry, C. A. Nicolaides and D. R. Beck (editors), D. Reidel (1978), p. 105ff.. This is a re-vitalization of an older ideaootnotetextI. Oksuz and O. Sinanoglu, Phys. Rev. 181, 54 (1969).. We display relationships between angular factors involving the exchange of holes and electrons (e.g. f^6 vs f^8, f^13d vs fd^9). We apply the results to Tb IV and Gd IV, whose spectra is largely unknown, but which may play a role in MRI medicine as endohedral metallofullerenes (e.g. Gd3N-C80ootnotetextM. C. Qian and S. N. Khanna, J. Appl. Phys. 101, 09E105 (2007).). Pr III results are in good agreement (910 cm-1) with experiment. Pu I 5f^2 radial pair energies are also presented.

  8. Applying analytic hierarchy process to assess healthcare-oriented cloud computing service systems.

    PubMed

    Liao, Wen-Hwa; Qiu, Wan-Li

    2016-01-01

    Numerous differences exist between the healthcare industry and other industries. Difficulties in the business operation of the healthcare industry have continually increased because of the volatility and importance of health care, changes to and requirements of health insurance policies, and the statuses of healthcare providers, which are typically considered not-for-profit organizations. Moreover, because of the financial risks associated with constant changes in healthcare payment methods and constantly evolving information technology, healthcare organizations must continually adjust their business operation objectives; therefore, cloud computing presents both a challenge and an opportunity. As a response to aging populations and the prevalence of the Internet in fast-paced contemporary societies, cloud computing can be used to facilitate the task of balancing the quality and costs of health care. To evaluate cloud computing service systems for use in health care, providing decision makers with a comprehensive assessment method for prioritizing decision-making factors is highly beneficial. Hence, this study applied the analytic hierarchy process, compared items related to cloud computing and health care, executed a questionnaire survey, and then classified the critical factors influencing healthcare cloud computing service systems on the basis of statistical analyses of the questionnaire results. The results indicate that the primary factor affecting the design or implementation of optimal cloud computing healthcare service systems is cost effectiveness, with the secondary factors being practical considerations such as software design and system architecture.

  9. Methodology for computing white matter nerve fiber orientation in human histological slices

    PubMed Central

    Wisco, Jonathan J.; Hageman, Nathan; Schettler, Stephen P.; Wong, Anita; Vinters, Harry V.; Teng, Chia-Chi; Bangerter, Neal K.

    2016-01-01

    Background The gold standard for mapping nerve fiber orientation in white matter of the human brain is histological analysis through biopsy. Such mappings are a crucial step in validating non-invasive techniques for assessing nerve fiber orientation in the human brain by using diffusion MRI. However, the manual extraction of nerve fiber directions of histological slices is tedious, time consuming, and prone to human error. New Method The presented semi-automated algorithm first creates a binary-segmented mask of the nerve fibers in the histological image, and then extracts an estimate of average directionality of nerve fibers through a Fourier-domain analysis of the masked image. It also generates an uncertainty level for its estimate of average directionality. Results and Comparison with Existing Methods The average orientations of the semi-automatic method were first compared to a qualitative expert opinion based on visual inspection of nerve fibers. A weighted RMS difference between the expert estimate and the algorithmically-determined angle (weighted by expert's confidence in his estimate) was 15.4 degrees, dropping to 9.9 degrees when only cases with an expert confidence level of greater than 50% were included. The algorithmically-determined angles were then compared with angles extracted using a manual segmentation technique, yielding an RMS difference of 11.2 degrees. Conclusion The presented semi-automated method is in good agreement with both qualitative and quantitative manual expert-based approaches for estimating directionality of nerve fibers in white matter from images of stained histological slices of the human brain. PMID:26709015

  10. Imaging of nanoparticles with dual-energy computed tomography

    PubMed Central

    Ducote, J L; Alivov, Y; Molloi, S

    2011-01-01

    A simulation study was performed to determine the feasibility and performance of imaging nanoparticles as contrast agents in dual energy computed tomography. An analytical simulation model was used to model the relevant signal to noise ratio (SNR) in dual energy imaging for the specific case of a three material patient phantom consisting of water, calcium hydroxyapatite and contrast agent. Elemental gold and iodine were both considered as contrast agents. Simulations were performed for a range of monenergetic (20 - 150 keV) and polyenergetic (20-150 kVp) beam spectra. A reference configuration was defined with beam energies of 80 kVp and 140 kVp to match current clinical practice. The effect of adding a silver filter to the high energy beam was also studied. A figure of merit (FOM) which normalized the dual energy SNR to the square root of patient integral dose, was calculated for all cases. The units of the FOM were keV−1/2. A simple Rose model of detectability was used to estimate the minimum concentration of either elements needed to be detected (SNR>5). For monoenergetic beams, the peak FOM of gold was 6.4 × 10−6 keV−1/2while the peak FOM of iodine was 3.1 × 10−6 keV−1/2, a factor of approximately 2 greater for gold. For polyenergetic spectra, at the reference energies of 80 kVp and 140 kVp, the FOM for gold and iodine was 1.65 × 10−6 keV−1/2 and 5.0 × 10−7 keV−1/2, respectively, a factor of approximately 3.3 greater. Also at these energies, the minimum detectable concentration of gold was estimated to be 58.5 mg/mL while iodine was estimated to be 117.5 mg/mL. The results suggest that the imaging of a gold nanoparticle contrast agent is well suited to current conditions used in clinical imaging. The addition of a silver filter of 800 μm further increased the image quality of the gold signal by approximately 50% for the same absorbed dose to the patient. PMID:21386141

  11. Imaging of nanoparticles with dual-energy computed tomography.

    PubMed

    Ducote, J L; Alivov, Y; Molloi, S

    2011-04-07

    A simulation study was performed to determine the feasibility and performance of imaging nanoparticles as contrast agents in dual-energy computed tomography. An analytical simulation model was used to model the relevant signal-to-noise ratio (SNR) in dual-energy imaging for the specific case of a three-material patient phantom consisting of water, calcium hydroxyapatite and contrast agent. Elemental gold and iodine were both considered as contrast agents. Simulations were performed for a range of monoenergetic (20-150 keV) and polyenergetic (20-150 kVp) beam spectra. A reference configuration was defined with beam energies of 80 and 140 kVp to match current clinical practice. The effect of adding a silver filter to the high-energy beam was also studied. A figure of merit (FOM), which normalized the dual-energy SNR to the square root of the patient integral dose, was calculated for all cases. The units of the FOM were keV(-1/2). A simple Rose model of detectability was used to estimate the minimum concentration of either elements needed to be detected (SNR > 5). For monoenergetic beams, the peak FOM of gold was 6.4 × 10(-6) keV(-1/2), while the peak FOM of iodine was 3.1 × 10(-6) keV(-1/2), a factor of approximately 2 greater for gold. For polyenergetic spectra, at the reference energies of 80 and 140 kVp, the FOM for gold and iodine was 1.65 × 10(-6) and 5.0 × 10(-7) keV(-1/2), respectively, a factor of approximately 3.3 greater. Also at these energies, the minimum detectable concentration of gold was estimated to be 58.5 mg mL(-1), while iodine was estimated to be 117.5 mg mL(-1). The results suggest that the imaging of a gold nanoparticle contrast agent is well suited to current conditions used in clinical imaging. The addition of a silver filter of 800 µm further increased the image quality of the gold signal by approximately 50% for the same absorbed dose to the patient.

  12. Time-oriented hierarchical method for computation of principal components using subspace learning algorithm.

    PubMed

    Jankovic, Marko; Ogawa, Hidemitsu

    2004-10-01

    Principal Component Analysis (PCA) and Principal Subspace Analysis (PSA) are classic techniques in statistical data analysis, feature extraction and data compression. Given a set of multivariate measurements, PCA and PSA provide a smaller set of "basis vectors" with less redundancy, and a subspace spanned by them, respectively. Artificial neurons and neural networks have been shown to perform PSA and PCA when gradient ascent (descent) learning rules are used, which is related to the constrained maximization (minimization) of statistical objective functions. Due to their low complexity, such algorithms and their implementation in neural networks are potentially useful in cases of tracking slow changes of correlations in the input data or in updating eigenvectors with new samples. In this paper we propose PCA learning algorithm that is fully homogeneous with respect to neurons. The algorithm is obtained by modification of one of the most famous PSA learning algorithms--Subspace Learning Algorithm (SLA). Modification of the algorithm is based on Time-Oriented Hierarchical Method (TOHM). The method uses two distinct time scales. On a faster time scale PSA algorithm is responsible for the "behavior" of all output neurons. On a slower scale, output neurons will compete for fulfillment of their "own interests". On this scale, basis vectors in the principal subspace are rotated toward the principal eigenvectors. At the end of the paper it will be briefly analyzed how (or why) time-oriented hierarchical method can be used for transformation of any of the existing neural network PSA method, into PCA method.

  13. Thrifty: An Exascale Architecture for Energy Proportional Computing

    SciTech Connect

    Torrellas, Josep

    2014-12-23

    The objective of this project is to design different aspects of a novel exascale architecture called Thrifty. Our goal is to focus on the challenges of power/energy efficiency, performance, and resiliency in exascale systems. The project includes work on computer architecture (Josep Torrellas from University of Illinois), compilation (Daniel Quinlan from Lawrence Livermore National Laboratory), runtime and applications (Laura Carrington from University of California San Diego), and circuits (Wilfred Pinfold from Intel Corporation). In this report, we focus on the progress at the University of Illinois during the last year of the grant (September 1, 2013 to August 31, 2014). We also point to the progress in the other collaborating institutions when needed.

  14. Power/energy use cases for high performance computing.

    SciTech Connect

    Laros, James H.,; Kelly, Suzanne M; Hammond, Steven; Elmore, Ryan; Munch, Kristin

    2013-12-01

    Power and Energy have been identified as a first order challenge for future extreme scale high performance computing (HPC) systems. In practice the breakthroughs will need to be provided by the hardware vendors. But to make the best use of the solutions in an HPC environment, it will likely require periodic tuning by facility operators and software components. This document describes the actions and interactions needed to maximize power resources. It strives to cover the entire operational space in which an HPC system occupies. The descriptions are presented as formal use cases, as documented in the Unified Modeling Language Specification [1]. The document is intended to provide a common understanding to the HPC community of the necessary management and control capabilities. Assuming a common understanding can be achieved, the next step will be to develop a set of Application Programing Interfaces (APIs) to which hardware vendors and software developers could utilize to steer power consumption.

  15. Preferred orientation in carbon and boron nitride: Does a thermodynamic theory of elastic strain energy get it right. [C; BN

    SciTech Connect

    McCarty, K.F. )

    1999-09-01

    We address whether the elastic strain-energy theory (minimizing the Gibbs energy of a stressed crystal) of McKenzie and co-workers [D. R. McKenzie and M. M. M. Bilek, J. Vac. Sci. Technol. A [bold 16], 2733 (1998)] adequately explains the preferred orientation observed in carbon and BN films. In the formalism, the Gibbs energy of the cubic materials diamond and cubic boron includes the strain that occurs when the phases form, through specific structural transformations, from graphitic precursors. This treatment violates the requirement of thermodynamics that the Gibbs energy be a path-independent, state function. If the cubic phases are treated using the same (path-independent) formalism applied to the graphitic materials, the crystallographic orientation of lowest Gibbs energy is not that observed experimentally. For graphitic (hexagonal) carbon and BN, an elastic strain approach seems inappropriate because the compressive stresses in energetically deposited films are orders of magnitude higher than the elastic limit of the materials. Furthermore, using the known elastic constants of either ordered or disordered graphitic materials, the theory does not predict the orientation observed by experiment. [copyright] [ital 1999 American Vacuum Society.

  16. Legacy systems: managing evolution through integration in a distributed and object-oriented computing environment.

    PubMed Central

    Lemaitre, D.; Sauquet, D.; Fofol, I.; Tanguy, L.; Jean, F. C.; Degoulet, P.

    1995-01-01

    Legacy systems are crucial for organizations since they support key functionalities. But they become obsolete with aging and the apparition of new techniques. Managing their evolution is a key issue in software engineering. This paper presents a strategy that has been developed at Broussais University Hospital in Paris to make a legacy system devoted to the management of health care units evolve towards a new up-to-date software. A two-phase evolution pathway is described. The first phase consists in separating the interface from the data storage and application control and in using a communication channel between the individualized components. The second phase proposes to use an object-oriented DBMS in place of the homegrown system. An application example for the management of hypertensive patients is described. PMID:8563252

  17. MOUSE (MODULAR ORIENTED UNCERTAINTY SYSTEM): A COMPUTERIZED UNCERTAINTY ANALYSIS SYSTEM (FOR MICRO- COMPUTERS)

    EPA Science Inventory

    Environmental engineering calculations involving uncertainties; either in the model itself or in the data, are far beyond the capabilities of conventional analysis for any but the simplest of models. There exist a number of general-purpose computer simulation languages, using Mon...

  18. Context-Oriented Communication and the Design of Computer-Supported Discursive Learning

    ERIC Educational Resources Information Center

    Herrmann, Thomas; Kienle, Andrea

    2008-01-01

    Computer-supported discursive learning (CSDL) systems for the support of asynchronous discursive learning need to fulfill specific socio-technical conditions. To understand these conditions, we employed design experiments combining aspects of communication theory, empirical findings, and continuous improvement of the investigated prototypes. Our…

  19. An Integrated, Cooperative Learning Oriented Freshman Civil Engineering Course: Computer Analysis in Civil Engineering.

    ERIC Educational Resources Information Center

    Hart, Frederick L.; Groccia, James E.

    Worcester Polytechnic Institute (Massachusetts) has developed a new freshman course titled "Computer Analysis in Civil Engineering" as part of a curriculum revision project which emphasizes critical thinking, cooperative group learning and problem solving, the integration of knowledge through projects, and student responsibility for…

  20. The Effectiveness of Instructional Orienting Activities in Computer-Based Instruction.

    ERIC Educational Resources Information Center

    Kenny, Richard F.

    Research literature pertaining to the use of instructional organizers is reviewed, and a comparative analysis is made of their effectiveness with computer-based instruction (CBI). One of the earliest forms of instructional organizer is the advance organizer, first proposed by David Ausubel (1960, 1963) which is meant to facilitate the retention of…

  1. Vertically oriented arrays of ReS2 nanosheets for electrochemical energy storage and electrocatalysis

    DOE PAGES

    Gao, Jian; Li, Lu; Tan, Jiawei; ...

    2016-05-17

    Here, transition-metal dichalcogenide (TMD) nanolayers show potential as high-performance catalysts in energy conversion and storage devices. Synthetic TMDs produced by chemical-vapor deposition (CVD) methods tend to grow parallel to the growth substrate. Here, we show that with the right precursors and appropriate tuning of the CVD growth conditions, ReS2 nanosheets can be made to orient perpendicular to the growth substrate. This accomplishes two important objectives; first, it drastically increases the wetted or exposed surface area of the ReS2 sheets, and second, it exposes the sharp edges and corners of the ReS2 sheets. We show that these structural features of themore » vertically grown ReS2 sheets can be exploited to significantly improve their performance as polysulfide immobilizers and electrochemical catalysts in lithium–sulfur (Li–S) batteries and in hydrogen evolution reactions (HER). After 300 cycles, the specific capacity of the Li–S battery with vertical ReS2 catalyst is retained above 750 mA h g–1, with only ~0.063% capacity decay per cycle, much better than the baseline battery (without ReS2), which shows ~0.184% capacity decay per cycle under the same test conditions. As a HER catalyst, the vertical ReS2 provides very small onset overpotential (<100 mV) and an exceptional exchange-current density (~67.6 μA/cm2), which is vastly superior to the baseline electrode without ReS2.« less

  2. A balanced filterless K-edge energy window multilayer detector for dual energy computed tomography

    NASA Astrophysics Data System (ADS)

    Allec, Nicholas; Karim, Karim S.

    2010-04-01

    Ross (or balanced) filter-based systems have been studied extensively in the past, however they have only recently been studied for medical applications such as computed tomography and contrast-enhanced mammography. Balanced filters are filters composed of different materials which have thicknesses designed to match the attenuation for all radiation energies except those within a certain energy window (between the K-edges of the filter materials). Images obtained using different filters to attenuate the incident x-rays can be subtracted to obtain an image which contains information solely within the energy window. The disadvantage of this image acquisition method is the requirement of a separate exposure for each filter. This can lead to motion artifacts in the resulting image for example due to cardiac, respiratory, or patient movement. In this paper we investigate a filterless, multilayer detector design using the general concept of balanced filters. In the proposed detector, energy discrimination is achieved using stacked layers of different conversion materials. Similar to how the thicknesses of balanced filters are chosen, the thicknesses of the conversion layers are designed to match the attenuation of x-rays except between the K-edges of the conversion materials. Motion artifacts are suppressed in the final image due to the simultaneous acquisition of images on all layers during a single exposure. The proposed multilayer design can be used for a number of applications depending on the energy range of interest. To study the proposed design, we consider dual energy computed tomography (CT) using a gadolinium-based contrast agent.

  3. Service-Oriented Architecture for NVO and TeraGrid Computing

    NASA Technical Reports Server (NTRS)

    Jacob, Joseph; Miller, Craig; Williams, Roy; Steenberg, Conrad; Graham, Matthew

    2008-01-01

    The National Virtual Observatory (NVO) Extensible Secure Scalable Service Infrastructure (NESSSI) is a Web service architecture and software framework that enables Web-based astronomical data publishing and processing on grid computers such as the National Science Foundation's TeraGrid. Characteristics of this architecture include the following: (1) Services are created, managed, and upgraded by their developers, who are trusted users of computing platforms on which the services are deployed. (2) Service jobs can be initiated by means of Java or Python client programs run on a command line or with Web portals. (3) Access is granted within a graduated security scheme in which the size of a job that can be initiated depends on the level of authentication of the user.

  4. A stoichiometric calibration method for dual energy computed tomography

    NASA Astrophysics Data System (ADS)

    Bourque, Alexandra E.; Carrier, Jean-François; Bouchard, Hugo

    2014-04-01

    The accuracy of radiotherapy dose calculation relies crucially on patient composition data. The computed tomography (CT) calibration methods based on the stoichiometric calibration of Schneider et al (1996 Phys. Med. Biol. 41 111-24) are the most reliable to determine electron density (ED) with commercial single energy CT scanners. Along with the recent developments in dual energy CT (DECT) commercial scanners, several methods were published to determine ED and the effective atomic number (EAN) for polyenergetic beams without the need for CT calibration curves. This paper intends to show that with a rigorous definition of the EAN, the stoichiometric calibration method can be successfully adapted to DECT with significant accuracy improvements with respect to the literature without the need for spectrum measurements or empirical beam hardening corrections. Using a theoretical framework of ICRP human tissue compositions and the XCOM photon cross sections database, the revised stoichiometric calibration method yields Hounsfield unit (HU) predictions within less than ±1.3 HU of the theoretical HU calculated from XCOM data averaged over the spectra used (e.g., 80 kVp, 100 kVp, 140 kVp and 140/Sn kVp). A fit of mean excitation energy (I-value) data as a function of EAN is provided in order to determine the ion stopping power of human tissues from ED-EAN measurements. Analysis of the calibration phantom measurements with the Siemens SOMATOM Definition Flash dual source CT scanner shows that the present formalism yields mean absolute errors of (0.3 ± 0.4)% and (1.6 ± 2.0)% on ED and EAN, respectively. For ion therapy, the mean absolute errors for calibrated I-values and proton stopping powers (216 MeV) are (4.1 ± 2.7)% and (0.5 ± 0.4)%, respectively. In all clinical situations studied, the uncertainties in ion ranges in water for therapeutic energies are found to be less than 1.3 mm, 0.7 mm and 0.5 mm for protons, helium and carbon ions respectively, using a generic

  5. A primer on the energy efficiency of computing

    SciTech Connect

    Koomey, Jonathan G.

    2015-03-30

    The efficiency of computing at peak output has increased rapidly since the dawn of the computer age. This paper summarizes some of the key factors affecting the efficiency of computing in all usage modes. While there is still great potential for improving the efficiency of computing devices, we will need to alter how we do computing in the next few decades because we are finally approaching the limits of current technologies.

  6. Integrated Computational Protocol for Analyzing Quadrupolar Splittings from Natural Abundance Deuterium NMR Spectra in (Chiral) Oriented Media.

    PubMed

    Navarro-Vazquez, Armando; Berdagué, Philippe; Lesot, Philippe Georges Julien

    2017-03-03

    Despite its low natural abundance, deuterium NMR in weakly oriented (chiral) solvents gives easy access to deuterium residual quadrupolar couplings (2H-RQCs), which are formally equivalent to one-bond 1DCH (13C-1H)-RDCs for calculation of the Saupe order matrix, furnishing similar information to study molecular structure and orientational behavior. In addition, the quadrupolar interaction is one order of magnitude larger than the dipolar interaction, making 2H-RQC analysis much more sensitive tool for structural analysis. Subtle structural differences as well as tiny differences in the molecular alignment of different enantiomers in chiral aligning media can be detected. In order to promote this approach towards organic chemists interested in exploiting the analytical advantages of anisotropic, natural abundance deuterium NMR (NAD NMR), we describe a 2H-RQC/DFT-based integrated computational protocol for the evaluation of the order parameters of aligned solutes via singular value decomposition. Examples of 2H-RQC-assisted analysis of chiral and prochiral molecules dissolved in various polypeptide lyotropic chiral liquid crystals are reported. They illustrate the power of this hyphenated approach and in particular to understand the alignment processes and the role of molecular shape in the ordering mechanism through the determination of inter-tensor angles between alignment tensors and inertia tensors.

  7. Stable pseudoanalytical computation of electromagnetic fields from arbitrarily-oriented dipoles in cylindrically stratified media

    NASA Astrophysics Data System (ADS)

    Moon, Haksu; Teixeira, Fernando L.; Donderici, Burkay

    2014-09-01

    Computation of electromagnetic fields due to point sources (Hertzian dipoles) in cylindrically stratified media is a classical problem for which analytical expressions of the associated tensor Green's function have been long known. However, under finite-precision arithmetic, direct numerical computations based on the application of such analytical (canonical) expressions invariably lead to underflow and overflow problems related to the poor scaling of the eigenfunctions (cylindrical Bessel and Hankel functions) for extreme arguments and/or high-order, as well as convergence problems related to the numerical integration over the spectral wavenumber and to the truncation of the infinite series over the azimuth mode number. These problems are exacerbated when a disparate range of values is to be considered for the layers' thicknesses and material properties (resistivities, permittivities, and permeabilities), the transverse and longitudinal distances between source and observation points, as well as the source frequency. To overcome these challenges in a systematic fashion, we introduce herein different sets of range-conditioned, modified cylindrical functions (in lieu of standard cylindrical eigenfunctions), each associated with nonoverlapped subdomains of (numerical) evaluation to allow for stable computations under any range of physical parameters. In addition, adaptively-chosen integration contours are employed in the complex spectral wavenumber plane to ensure convergent numerical integration in all cases. We illustrate the application of the algorithm to problems of geophysical interest involving layer resistivities ranging from 1000 Ω m to 10-8 Ω m, frequencies of operation ranging from 10 MHz down to the low magnetotelluric range of 0.01 Hz, and for various combinations of layer thicknesses.

  8. Region-oriented CT image representation for reducing computing time of Monte Carlo simulations

    SciTech Connect

    Sarrut, David; Guigues, Laurent

    2008-04-15

    Purpose. We propose a new method for efficient particle transportation in voxelized geometry for Monte Carlo simulations. We describe its use for calculating dose distribution in CT images for radiation therapy. Material and methods. The proposed approach, based on an implicit volume representation named segmented volume, coupled with an adapted segmentation procedure and a distance map, allows us to minimize the number of boundary crossings, which slows down simulation. The method was implemented with the GEANT4 toolkit and compared to four other methods: One box per voxel, parameterized volumes, octree-based volumes, and nested parameterized volumes. For each representation, we compared dose distribution, time, and memory consumption. Results. The proposed method allows us to decrease computational time by up to a factor of 15, while keeping memory consumption low, and without any modification of the transportation engine. Speeding up is related to the geometry complexity and the number of different materials used. We obtained an optimal number of steps with removal of all unnecessary steps between adjacent voxels sharing a similar material. However, the cost of each step is increased. When the number of steps cannot be decreased enough, due for example, to the large number of material boundaries, such a method is not considered suitable. Conclusion. This feasibility study shows that optimizing the representation of an image in memory potentially increases computing efficiency. We used the GEANT4 toolkit, but we could potentially use other Monte Carlo simulation codes. The method introduces a tradeoff between speed and geometry accuracy, allowing computational time gain. However, simulations with GEANT4 remain slow and further work is needed to speed up the procedure while preserving the desired accuracy.

  9. Kane's equations of flexible multibody systems with tree structure - A computer-oriented modeling approach

    NASA Astrophysics Data System (ADS)

    Jin, Liang; Bauer, Helmut F.

    1991-09-01

    Kane's dynamical model of flexible multibody space systems with tree structure is developed in this paper. The system topology is restricted to a tree configuration which is defined as an arbitrary set of flexible and rigid bodies connected by hinges characterizing relative translations and rotations of two adjoining bodies. The relative translational velocities, angular velocities, and the differential of model coordinates are selected as the generalized velocities. The motion equations of minimum dimension are derived via Kane's method. The resulting equations are suitable for automatic generation and computer simulation.

  10. Dual-energy computed tomography for gout diagnosis and management.

    PubMed

    Dalbeth, Nicola; Choi, Hyon K

    2013-01-01

    The central feature of gout is deposition of monosodium urate crystals. Dual-energy computed tomography (DECT) is a recently developed advanced imaging method that enables visualisation of urate deposits by analysis of the chemical composition of the scanned materials. This review summarises recent research describing the use of DECT in gout management. This technology may assist in both diagnosis and monitoring of the disease. Studies of patients with established disease indicate diagnostic accuracy for gout is high. Excellent inter-reader agreement has been reported for detection of urate deposits by use of DECT. Automated volume assessment software also enables rapid and reproducible measurement of urate deposits within tophi, suggesting that this modality may be useful for monitoring the disease. Although several case reports indicate DECT can be used to reveal reduction in the size of urate deposits, the sensitivity to change in response to urate-lowering therapy has not yet been systematically reported. DECT images reveal variable urate deposition within tophi of the same physical size. The ability to visualise urate deposits in tissue may provide new insights into the pathology and mechanisms of gout.

  11. Dynamics of flexible bodies in tree topology - A computer oriented approach

    NASA Technical Reports Server (NTRS)

    Singh, R. P.; Vandervoort, R. J.; Likins, P. W.

    1984-01-01

    An approach suited for automatic generation of the equations of motion for large mechanical systems (i.e., large space structures, mechanisms, robots, etc.) is presented. The system topology is restricted to a tree configuration. The tree is defined as an arbitrary set of rigid and flexible bodies connected by hinges characterizing relative translations and rotations of two adjoining bodies. The equations of motion are derived via Kane's method. The resulting equation set is of minimum dimension. Dynamical equations are imbedded in a computer program called TREETOPS. Extensive control simulation capability is built in the TREETOPS program. The simulation is driven by an interactive set-up program resulting in an easy to use analysis tool.

  12. Electrolytes induce long-range orientational order and free energy changes in the H-bond network of bulk water

    PubMed Central

    Chen, Yixing; Okur, Halil I.; Gomopoulos, Nikolaos; Macias-Romero, Carlos; Cremer, Paul S.; Petersen, Poul B.; Tocci, Gabriele; Wilkins, David M.; Liang, Chungwen; Ceriotti, Michele; Roke, Sylvie

    2016-01-01

    Electrolytes interact with water in many ways: changing dipole orientation, inducing charge transfer, and distorting the hydrogen-bond network in the bulk and at interfaces. Numerous experiments and computations have detected short-range perturbations that extend up to three hydration shells around individual ions. We report a multiscale investigation of the bulk and surface of aqueous electrolyte solutions that extends from the atomic scale (using atomistic modeling) to nanoscopic length scales (using bulk and interfacial femtosecond second harmonic measurements) to the macroscopic scale (using surface tension experiments). Electrolytes induce orientational order at concentrations starting at 10 μM that causes nonspecific changes in the surface tension of dilute electrolyte solutions. Aside from ion-dipole interactions, collective hydrogen-bond interactions are crucial and explain the observed difference of a factor of 6 between light water and heavy water. PMID:27152357

  13. Computational fluid dynamics investigation of human aspiration in low velocity air: orientation effects on nose-breathing simulations.

    PubMed

    Anderson, Kimberly R; Anthony, T Renée

    2014-06-01

    An understanding of how particles are inhaled into the human nose is important for developing samplers that measure biologically relevant estimates of exposure in the workplace. While previous computational mouth-breathing investigations of particle aspiration have been conducted in slow moving air, nose breathing still required exploration. Computational fluid dynamics was used to estimate nasal aspiration efficiency for an inhaling humanoid form in low velocity wind speeds (0.1-0.4 m s(-1)). Breathing was simplified as continuous inhalation through the nose. Fluid flow and particle trajectories were simulated over seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135, 180°). Sensitivities of the model simplification and methods were assessed, particularly the placement of the recessed nostril surface and the size of the nose. Simulations identified higher aspiration (13% on average) when compared to published experimental wind tunnel data. Significant differences in aspiration were identified between nose geometry, with the smaller nose aspirating an average of 8.6% more than the larger nose. Differences in fluid flow solution methods accounted for 2% average differences, on the order of methodological uncertainty. Similar trends to mouth-breathing simulations were observed including increasing aspiration efficiency with decreasing freestream velocity and decreasing aspiration with increasing rotation away from the oncoming wind. These models indicate nasal aspiration in slow moving air occurs only for particles <100 µm.

  14. AZTECA, a y-y diagram oriented interactive computer program for optical system design and optimization

    NASA Astrophysics Data System (ADS)

    Flores-Hernandez, Ricardo

    1995-09-01

    The Centro de Investigaciones en Optica is developing the AZTECA optical design program to exploit the full synthesis capabilities intrinsic to Delano's y-y method. Both the y- y diagram and its dual the (omega) -(omega) diagram, are manipulated in real time to introduce changes at any point or line in those diagrams. These changes result in altered new versions of the optical system by means of a specialized subroutine that incorporates the fundamental synthesis equations for those diagrams. To display results on the computer's screen as the optimization process progress, AZTECA makes wide use of the fact that the y-y and the (omega) -(omega) diagrams display graphically all the first order attributes of an optical system. This program adjoins to these features the calculation of Buchdahl's 3rd, 5th, and 7th order aberration coefficients to the output. This results in a real time display of the system's paraxial and aberrational behavior. Efficient graphic displays, the program's modular structure and an interactive mode of operation, also contribute to make the AZTECA a versatile platform. It will be further developed as a new tool for efficient optical system design.

  15. Preparation of forefinger's sequence on keyboard orients ocular fixations on computer screen.

    PubMed

    Coutté, Alexandre; Olivier, Gérard; Faure, Sylvane; Baccino, Thierry

    2014-08-01

    This study examined the links between attention, hand movements and eye movements when performed in different spatial areas. Participants performed a visual search task on a computer screen while preparing to press two keyboard keys sequentially with their index. Results showed that the planning of the manual sequence influenced the latency of the first saccade and the placement of the first fixation. In particular, even if the first fixation placement was influenced by the combination of both components of the prepared manual sequence in some trials, it was affected principally by the first component of the prepared manual sequence. Moreover, the probability that the first fixation placement did reflect a combination of both components of the manual sequence was correlated with the speed of the second component. This finding suggests that the preparation of the second component of the sequence influence simultaneous oculomotor behavior when motor control of the manual sequence relied on proactive motor planning. These results are discussed taking into account the current debate on the eye/hand coordination research.

  16. Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

    PubMed

    Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

    2013-03-01

    A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

  17. Thermal behavior of buildings and the role of computers in energy conservation

    NASA Astrophysics Data System (ADS)

    Oliver, P. P.

    1981-10-01

    The interrelationship between the climate, building design and energy consumption are considered and, the use of the digital computer to evaluate the potential of different energy conservation measures in buildings is discussed.

  18. The updated algorithm of the Energy Consumption Program (ECP): A computer model simulating heating and cooling energy loads in buildings

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.; Strain, D. M.; Chai, V. W.; Higgins, S.

    1979-01-01

    The energy Comsumption Computer Program was developed to simulate building heating and cooling loads and compute thermal and electric energy consumption and cost. This article reports on the new additional algorithms and modifications made in an effort to widen the areas of application. The program structure was rewritten accordingly to refine and advance the building model and to further reduce the processing time and cost. The program is noted for its very low cost and ease of use compared to other available codes. The accuracy of computations is not sacrificed however, since the results are expected to lie within + or - 10% of actual energy meter readings.

  19. Money for Research, Not for Energy Bills: Finding Energy and Cost Savings in High Performance Computer Facility Designs

    SciTech Connect

    Drewmark Communications; Sartor, Dale; Wilson, Mark

    2010-07-01

    High-performance computing facilities in the United States consume an enormous amount of electricity, cutting into research budgets and challenging public- and private-sector efforts to reduce energy consumption and meet environmental goals. However, these facilities can greatly reduce their energy demand through energy-efficient design of the facility itself. Using a case study of a facility under design, this article discusses strategies and technologies that can be used to help achieve energy reductions.

  20. Saving Energy and Money: A Lesson in Computer Power Management

    ERIC Educational Resources Information Center

    Lazaros, Edward J.; Hua, David

    2012-01-01

    In this activity, students will develop an understanding of the economic impact of technology by estimating the cost savings of power management strategies in the classroom. Students will learn how to adjust computer display settings to influence the impact that the computer has on the financial burden to the school. They will use mathematics to…

  1. Computer-Aided Energy Analysis for Buildings: An Assessment of Its Value for Students of Technology and Architecture.

    ERIC Educational Resources Information Center

    Ridenour, Steven

    1981-01-01

    Demonstrates that computer aided energy analysis improves students' (N=29) comprehension and prediction accuracy of energy consumption in buildings and confirms that a reasonably accurate building energy analysis computer program can be designed for student users. (Author/SK)

  2. Solar energy harvesting in the epicuticle of the oriental hornet ( Vespa orientalis)

    NASA Astrophysics Data System (ADS)

    Plotkin, Marian; Hod, Idan; Zaban, Arie; Boden, Stuart A.; Bagnall, Darren M.; Galushko, Dmitry; Bergman, David J.

    2010-12-01

    The Oriental hornet worker correlates its digging activity with solar insolation. Solar radiation passes through the epicuticle, which exhibits a grating-like structure, and continues to pass through layers of the exo-endocuticle until it is absorbed by the pigment melanin in the brown-colored cuticle or xanthopterin in the yellow-colored cuticle. The correlation between digging activity and the ability of the cuticle to absorb part of the solar radiation implies that the Oriental hornet may harvest parts of the solar radiation. In this study, we explore this intriguing possibility by analyzing the biophysical properties of the cuticle. We use rigorous coupled wave analysis simulations to show that the cuticle surfaces are structured to reduced reflectance and act as diffraction gratings to trap light and increase the amount absorbed in the cuticle. A dye-sensitized solar cell (DSSC) was constructed in order to show the ability of xanthopterin to serve as a light-harvesting molecule.

  3. Orientation dependent size effects in single crystalline anisotropic nanoplates with regard to surface energy

    NASA Astrophysics Data System (ADS)

    Assadi, Abbas; Salehi, Manouchehr; Akhlaghi, Mehdi

    2015-07-01

    In this work, size dependent behavior of single crystalline normal and auxetic anisotropic nanoplates is discussed with consideration of material surface stresses via a generalized model. Bending of pressurized nanoplates and their fundamental resonant frequency are discussed for different crystallographic directions and anisotropy degrees. It is explained that the orientation effects are considerable when the nanoplates' edges are pinned but for clamped nanoplates, the anisotropy effect may be ignored. The size effects are the highest when the simply supported nanoplates are parallel to [110] direction but as the anisotropy gets higher, the size effects are reduced. The orientation effect is also discussed for possibility of self-instability occurrence in nanoplates. The results in simpler cases are compared with previous experiments for nanowires but with a correction factor. There are still some open questions for future studies.

  4. Orientation and energy-transfer studies on chlorophyll in the photosynthetic membrane

    SciTech Connect

    Nairn, J.A.

    1981-12-01

    The two methods of study used for the light reactions of photosynthesis are orientation dependent spectroscopy and picosecond resolution of the fluorescence decay kinetics. Analysis of spectroscopic measurements on complex partially ordered ensembls, such as photosynthetic systems, is usually limited by knowledge of the orientational distribution function. A new method of parametrically representing the distribution function using a physical model of the partially ordered ensemble is described. The parametric representation of the distribution function is the density of states function. Many formulas are included which can be used to calculate density of state functions for a large range of problems. Fluorescence decay kinetics in chloroplasts from green plants and algae are investigated using a synchronously pumped, mode-locked dye laser as an excitation source.

  5. Effect of fiber orientation and cross section of composite tubes on their energy absorption ability in axial dynamic loading

    NASA Astrophysics Data System (ADS)

    Shokrieh, M. M.; Tozandehjani, H.; Omidi, M. J.

    2009-11-01

    The crushing behavior of composite tubes in axial impact loading is investigated. Tubes of circular and rectangular cross section are simulated using an LS-DYNA software. The effect of fiber orientation on the energy absorbed in laminated composite tubes is also studied. The results obtained show that rectangular tubes absorb less energy than circular ones, and their maximum crushing load is also lower. The composite tubes with a [+θ/ -θ] lay-up configuration absorb a minimum amount of energy at θ = 15°. The simulation results for a rectangular composite tube with a [+30/-30] lay-up configuration are compared with available experimental data. Cylindrical composite tubes fabricated from woven glass/polyester composites with different lay-ups were also tested using a drop-weight impact tester, and very good agreement between experimental and numerical results is achieved.

  6. Structural and orientation effects on electronic energy transfer between silicon quantum dots with dopants and with silver adsorbates.

    PubMed

    Vinson, N; Freitag, H; Micha, D A

    2014-06-28

    Starting from the atomic structure of silicon quantum dots (QDs), and utilizing ab initio electronic structure calculations within the Förster resonance energy transfer (FRET) treatment, a model has been developed to characterize electronic excitation energy transfer between QDs. Electronic energy transfer rates, KEET, between selected identical pairs of crystalline silicon quantum dots systems, either bare, doped with Al or P, or adsorbed with Ag and Ag3, have been calculated and analyzed to extend previous work on light absorption by QDs. The effects of their size and relative orientation on energy transfer rates for each system have also been considered. Using time-dependent density functional theory and the hybrid functional HSE06, the FRET treatment was employed to model electronic energy transfer rates within the dipole-dipole interaction approximation. Calculations with adsorbed Ag show that: (a) addition of Ag increases rates up to 100 times, (b) addition of Ag3 increases rates up to 1000 times, (c) collinear alignment of permanent dipoles increases transfer rates by an order of magnitude compared to parallel orientation, and (d) smaller QD-size increases transfer due to greater electronic orbitals overlap. Calculations with dopants show that: (a) p-type and n-type dopants enhance energy transfer up to two orders of magnitude, (b) surface-doping with P and center-doping with Al show the greatest rates, and (c) KEET is largest for collinear permanent dipoles when the dopant is on the outer surface and for parallel permanent dipoles when the dopant is inside the QD.

  7. Development of problem-oriented software packages for numerical studies and computer-aided design (CAD) of gyrotrons

    NASA Astrophysics Data System (ADS)

    Damyanova, M.; Sabchevski, S.; Zhelyazkov, I.; Vasileva, E.; Balabanova, E.; Dankov, P.; Malinov, P.

    2016-03-01

    Gyrotrons are the most powerful sources of coherent CW (continuous wave) radiation in the frequency range situated between the long-wavelength edge of the infrared light (far-infrared region) and the microwaves, i.e., in the region of the electromagnetic spectrum which is usually called the THz-gap (or T-gap), since the output power of other devices (e.g., solid-state oscillators) operating in this interval is by several orders of magnitude lower. In the recent years, the unique capabilities of the sub-THz and THz gyrotrons have opened the road to many novel and future prospective applications in various physical studies and advanced high-power terahertz technologies. In this paper, we present the current status and functionality of the problem-oriented software packages (most notably GYROSIM and GYREOSS) used for numerical studies, computer-aided design (CAD) and optimization of gyrotrons for diverse applications. They consist of a hierarchy of codes specialized to modelling and simulation of different subsystems of the gyrotrons (EOS, resonant cavity, etc.) and are based on adequate physical models, efficient numerical methods and algorithms.

  8. National Energy Research Scientific Computing Center 2007 Annual Report

    SciTech Connect

    Hules, John A.; Bashor, Jon; Wang, Ucilia; Yarris, Lynn; Preuss, Paul

    2008-10-23

    This report presents highlights of the research conducted on NERSC computers in a variety of scientific disciplines during the year 2007. It also reports on changes and upgrades to NERSC's systems and services aswell as activities of NERSC staff.

  9. Energy intensity of computer manufacturing: hybrid assessment combining process and economic input-output methods.

    PubMed

    Williams, Eric

    2004-11-15

    The total energy and fossil fuels used in producing a desktop computer with 17-in. CRT monitor are estimated at 6400 megajoules (MJ) and 260 kg, respectively. This indicates that computer manufacturing is energy intensive: the ratio of fossil fuel use to product weight is 11, an order of magnitude larger than the factor of 1-2 for many other manufactured goods. This high energy intensity of manufacturing, combined with rapid turnover in computers, results in an annual life cycle energy burden that is surprisingly high: about 2600 MJ per year, 1.3 times that of a refrigerator. In contrast with many home appliances, life cycle energy use of a computer is dominated by production (81%) as opposed to operation (19%). Extension of usable lifespan (e.g. by reselling or upgrading) is thus a promising approach to mitigating energy impacts as well as other environmental burdens associated with manufacturing and disposal.

  10. Energy Efficient Biomolecular Simulations with FPGA-based Reconfigurable Computing

    SciTech Connect

    Hampton, Scott S; Agarwal, Pratul K

    2010-05-01

    Reconfigurable computing (RC) is being investigated as a hardware solution for improving time-to-solution for biomolecular simulations. A number of popular molecular dynamics (MD) codes are used to study various aspects of biomolecules. These codes are now capable of simulating nanosecond time-scale trajectories per day on conventional microprocessor-based hardware, but biomolecular processes often occur at the microsecond time-scale or longer. A wide gap exists between the desired and achievable simulation capability; therefore, there is considerable interest in alternative algorithms and hardware for improving the time-to-solution of MD codes. The fine-grain parallelism provided by Field Programmable Gate Arrays (FPGA) combined with their low power consumption make them an attractive solution for improving the performance of MD simulations. In this work, we use an FPGA-based coprocessor to accelerate the compute-intensive calculations of LAMMPS, a popular MD code, achieving up to 5.5 fold speed-up on the non-bonded force computations of the particle mesh Ewald method and up to 2.2 fold speed-up in overall time-to-solution, and potentially an increase by a factor of 9 in power-performance efficiencies for the pair-wise computations. The results presented here provide an example of the multi-faceted benefits to an application in a heterogeneous computing environment.

  11. Computer Reduction Of Aerial Thermograms For Large Scale Energy Audits

    NASA Astrophysics Data System (ADS)

    Hazard, William R.

    1981-01-01

    A 32 kilobyte microcomputer is used for merging radiant (IR) temperatures of roof sections and building enclosures with meteorological data to produce per unit Energy Intensity Factors (EIFs) that are required for Comprehensive Energy planning. The EIFs can also be used as building blocks for a low cost RCS-type energy audit that has been shown to approximate the DOE model audit in terms of accuracy and completeness. The Type I or "Interactive Energy Audit" utilizes EIFs that are calculated from diffuse density levels of aerial IR recordings, supplemented by resident-supplied information concerning structural charac-teristics of a house and energy life-style of its occupants. Results of a statistical comparison between ASHRAE-based and IR audits of 175 single family homes in Garland, Texas show that, on the average, the aerial based heat loss estimates fall within a 10 percent error envelope around the true BTUH losses 90 percent of the time. The combination of an aerial infrared picture and an Interactive Energy Audit print-out have proven effective in (a) providing homeowners with the information they want from an energy audit; (b) persuading them to take appropriate remedial weatherization actions, and (c) screening out the homes that do not need a Class A audit, thereby eliminating the cost and bother of an on-site inspection.

  12. Computation of Adsorption Energies of Some Interstellar Species

    NASA Astrophysics Data System (ADS)

    Sil, Milan; Chakrabarti, Sandip Kumar; Das, Ankan; Majumdar, Liton; Gorai, Prasanta; Etim, Emmanuel; Arunan, Elangannan

    2016-07-01

    Adsorption energies of surface species are most crucial for chemical complexity of interstellar grain mantle. Aim of this work is to study the variation of the adsorption energies depending upon the nature of adsorbent. We use silicate and carbonaceous grains for the absorbents. For silicate grains, we use very simple crystalline ones, namely, Enstatite (MgSiO_3)_n, Ferrosilite (FeSiO_3)_n, Forsterite (Mg_2SiO_4)_n and Fayalite (Fe_2SiO_4)_n. We use n=1, 2, 4, 8 to study the variation of adsorption energies with the increase in cluster size. For carbonaceous grain, we use Coronene (polyaromatic hydrocarbon surface). Adsorption energy of all these species are calculated by means of quantum chemical calculation using self consistent density functional theory (DFT). MPWB1K hybrid meta-functional is employed since it has been proven useful to study the systems with weak interactions such as van der Waals interactions. Optimization are also carried out with MPWB1K/6-311g(d) and MPWB1K/6311g(d,p) and a comparison of adsorption energies are discussed for these two different basis sets. We use crystalline structure of the adsorbent. The adsorbate is placed in the different site of the grain with a suitable distance. The energy of adsorption for a species on the grain surface is defined as follows: E_a_d_s = E_s_s - (E_s_u_r_f_a_c_e + E_s_p_e_c_i_e_s), where E_a_d_s is the adsorption energy, E_s_s is the optimized energy for species placed in a suitable distance from the grain surface, E_s_u_r_f_a_c_e and E_s_p_e_c_i_e_s respectively are the optimized energies of the surface and species separately.

  13. Systematic parameter study of a nonlinear electromagnetic energy harvester with matched magnetic orientation: Numerical simulation and experimental investigation

    NASA Astrophysics Data System (ADS)

    Deng, Wei; Wang, Ya

    2017-02-01

    This paper reports the systematic parameter study of a tristable nonlinear electromagnetic energy harvester for ambient low-frequency vibration. Numerical simulations and experimental investigations are performed on the harvester which consists of a cantilever beam, a tip coil, two tip magnets and two external side magnets. The external side magnets are deployed symmetrically along a concave surface parallel to the trajectory of the cantilever tip with a controllable distance so that the magnetic orientation of the tip magnets are matched with that of the side magnets. Therefore, instead of the ternary position parameters (d, h, α), a binary parameters pair (d0, d) is used to characterize the position of the side magnets and the performance of the energy harvester. The magnetic force and magnetic field on the cantilever tip therefore depend on the relative distance in the tip displacement direction between the tip magnets and side magnets, but is independent of the position of the side magnets on the concave surface. The magnetic force (field)-distance relationship is measured experimentally and curve fitted to obtain explicit expressions, in order to characterize the magnetic force (field) when the side magnets are placed at varied positions along the concave surface. Numerical simulation is, then, performed to predict the electromagnetic voltage output and the bandwidth of the energy harvester. The simulation results coincided with the measured data. Significant broadband response is obtained experimentally and the maximum RMS power output is 40.2 mW at 0.45g of excitation. The proposed structure showcasing the matched magnetic orientation is characterized by the binary parameters pair (d0, d) and the systematic parametric approach could contribute to the design and study of nonlinear broadband energy harvesters.

  14. ND6600 computer in fusion-energy research

    SciTech Connect

    Young, K.G.

    1982-12-01

    The ND6600, a computer-based multichannel analyzer with eight ADCs, is used to acquire x-ray data. This manual introduces a user to the Nuclear Data system and contains the information necessary for the user to acquire, display, and record data. The manual also guides the programmer in the hardware and software maintenance of the system.

  15. PNNL Data-Intensive Computing for a Smarter Energy Grid

    SciTech Connect

    Carol Imhoff; Zhenyu Huang; Daniel Chavarria

    2009-11-01

    The Middleware for Data-Intensive Computing (MeDICi) Integration Framework, an integrated platform to solve data analysis and processing needs, supports PNNL research on the U.S. electric power grid. MeDICi is enabling development of visualizations of grid operations and vulnerabilities, with goal of near real-time analysis to aid operators in preventing and mitigating grid failures.

  16. PNNL Data-Intensive Computing for a Smarter Energy Grid

    ScienceCinema

    Carol Imhoff; Zhenyu (Henry) Huang; Daniel Chavarria

    2016-07-12

    The Middleware for Data-Intensive Computing (MeDICi) Integration Framework, an integrated platform to solve data analysis and processing needs, supports PNNL research on the U.S. electric power grid. MeDICi is enabling development of visualizations of grid operations and vulnerabilities, with goal of near real-time analysis to aid operators in preventing and mitigating grid failures.

  17. Computational Evaluation of a Latent Heat Energy Storage System

    DTIC Science & Technology

    2013-01-01

    Release; Distribution Unlimited. PA#13098 13. SUPPLEMENTARY NOTES Journal Article submitted to Solar Energy Materials and Solar Cells. 14. ABSTRACT...A system capable of receiving, absorbing, and converting solar energy was designed for use on a satellite in low Earth orbit. The proposed system, an...fronts the amount of solar irradiation required to fully utilize the phase change material was determined to be between 4 and 5 kW depending on the orbit

  18. Large Scale Computing and Storage Requirements for Fusion Energy Sciences: Target 2017

    SciTech Connect

    Gerber, Richard

    2014-05-02

    The National Energy Research Scientific Computing Center (NERSC) is the primary computing center for the DOE Office of Science, serving approximately 4,500 users working on some 650 projects that involve nearly 600 codes in a wide variety of scientific disciplines. In March 2013, NERSC, DOE?s Office of Advanced Scientific Computing Research (ASCR) and DOE?s Office of Fusion Energy Sciences (FES) held a review to characterize High Performance Computing (HPC) and storage requirements for FES research through 2017. This report is the result.

  19. Analysis of Different Methods for Computing Source Energy in the Context of Zero Energy Buildings

    SciTech Connect

    Torcellini, Paul A.; Bonnema, Eric; Goldwasser, David; Pless, Shanti

    2016-08-26

    Building energy consumption can only be measured at the site or at the point of utility interconnection with a building. Often, to evaluate the total energy impact, this site-based energy consumption is translated into source energy, that is, the energy at the point of fuel extraction. Consistent with this approach, the U.S. Department of Energy's (DOE) definition of zero energy buildings uses source energy as the metric to account for energy losses from the extraction, transformation, and delivery of energy. Other organizations, as well, use source energy to characterize the energy impacts. Four methods of making the conversion from site energy to source energy were investigated in the context of the DOE definition of zero energy buildings. These methods were evaluated based on three guiding principles--improve energy efficiency, reduce and stabilize power demand, and use power from nonrenewable energy sources as efficiently as possible. This study examines relative trends between strategies as they are implemented on very low-energy buildings to achieve zero energy. A typical office building was modeled and variations to this model performed. The photovoltaic output that was required to create a zero energy building was calculated. Trends were examined with these variations to study the impacts of the calculation method on the building's ability to achieve zero energy status. The paper will highlight the different methods and give conclusions on the advantages and disadvantages of the methods studied.

  20. The use of intraoperative computed tomography navigation in pituitary surgery promises a better intraoperative orientation in special cases

    PubMed Central

    Linsler, Stefan; Antes, Sebastian; Senger, Sebastian; Oertel, Joachim

    2016-01-01

    Objective: The safety of endoscopic skull base surgery can be enhanced by accurate navigation in preoperative computed tomography (CT) and magnetic resonance imaging (MRI). Here, we report our initial experience of real-time intraoperative CT-guided navigation surgery for pituitary tumors in childhood. Materials and Methods: We report the case of a 15-year-old girl with a huge growth hormone-secreting pituitary adenoma with supra- and perisellar extension. Furthermore, the skull base was infiltrated. In this case, we performed an endonasal transsphenoidal approach for debulking the adenoma and for chiasma decompression. We used an MRI neuronavigation (Medtronic Stealth Air System) which was registered via intraoperative CT scan (Siemens CT Somatom). Preexisting MRI studies (navigation protocol) were fused with the intraoperative CT scans to enable three-dimensional navigation based on MR and CT imaging data. Intraoperatively, we did a further CT scan for resection control. Results: The intraoperative accuracy of the neuronavigation was excellent. There was an adjustment of <1 mm. The navigation was very helpful for orientation on the destroyed skull base in the sphenoid sinus. After opening the sellar region and tumor debulking, we did a CT scan for resection control because the extent of resection was not credible evaluable in this huge infiltrating adenoma. Thereby, we were able to demonstrate a sufficient decompression of the chiasma and complete resection of the medial part of the adenoma in the intraoperative CT images. Conclusions: The use of intraoperative CT/MRI-guided neuronavigation for transsphenoidal surgery is a time-effective, safe, and technically beneficial technique for special cases. PMID:27695249

  1. GPU-enabled Computational Model of Electrochemical Energy Storage Systems

    NASA Astrophysics Data System (ADS)

    Andersen, Charles; Qiu, Gang; Kandasamy, Nagarajan; Sun, Ying

    2013-11-01

    We present a computational model of a Redox Flow Battery (RFB), which uses real pore-scale fiber geometry obtained through X-ray computed tomography (XCT). Our pore-scale approach is in contrast to the more common volume-averaged model, which considers the domain as a homogenous medium of uniform porosity. We apply a finite volume method to solve the coupled species and charge transport equations. The flow field in our system is evaluated using the Lattice Boltzmann method (LBM). To resolve the governing equations at the pore-scale of carbon fibers, which are on the order of tens of microns, is a highly computationally expensive task. To overcome this challenge, in lieu of traditional implementation with Message Passing Interface (MPI), we employ the use of Graphics Processing Units (GPUs) as a means of parallelization. The Butler-Volmer equation provides a coupling between the species and charge equations on the fiber surface. Scalability of the GPU implementation is examined along with the effects of fiber geometry, porosity, and flow rate on battery performance.

  2. Surface-Parallel Sensor Orientation for Assessing Energy Balance Components on Mountain Slopes

    NASA Astrophysics Data System (ADS)

    Serrano-Ortiz, P.; Sánchez-Cañete, E. P.; Olmo, F. J.; Metzger, S.; Pérez-Priego, O.; Carrara, A.; Alados-Arboledas, L.; Kowalski, A. S.

    2016-03-01

    The consistency of eddy-covariance measurements is often evaluated in terms of the degree of energy balance closure. Even over sloping terrain, instrumentation for measuring energy balance components is commonly installed horizontally, i.e. perpendicular to the geo-potential gradient. Subsequently, turbulent fluxes of sensible and latent heat are rotated perpendicular to the mean streamlines using tilt-correction algorithms. However, net radiation (Rn) and soil heat fluxes ( G) are treated differently, and typically only Rn is corrected to account for slope. With an applied case study, we show and argue several advantages of installing sensors surface-parallel to measure surface-normal Rn and G. For a 17 % south-west-facing slope, our results show that horizontal installation results in hysteresis in the energy balance closure and errors of up to 25 %. Finally, we propose an approximation to estimate the surface-normal Rn, when only vertical Rn measurements are available.

  3. Synthesis of titania thin films with controlled mesopore orientation: Nanostructure for energy conversion and storage

    NASA Astrophysics Data System (ADS)

    Nagpure, Suraj R.

    This dissertation addresses the synthesis mechanism of mesoporous titania thin films with 2D Hexagonal Close Packed (HCP) cylindrical nanopores by an evaporation-induced self-assembly (EISA) method with Pluronic surfactants P123 and F127 as structure directing agents, and their applications in photovoltaics and lithium ion batteries. To provide orthogonal alignment of the pores, surface modification of substrates with crosslinked surfactant has been used to provide a chemically neutral surface. GISAXS studies show not only that aging at 4 °C facilitates ordered mesostructure development, but also that aging at this temperature helps to provide orthogonal orientation of the cylindrical micelles which assemble into an ordered mesophase directly by a disorder-order transition. These films provide pores with 8-9 nm diameter, which is precisely the structure expected to provide short carrier diffusion length and high hole conductivity required for efficient bulk heterojunction solar cells. In addition, anatase titania is a n-type semiconductor with a band gap of +3.2 eV. Therefore, titania readily absorbs UV light with a wavelength below 387 nm. Because of this, these titania films can be used as window layers with a p-type semiconductor incorporated into the pores and at the top surface of the device to synthesize a photovoltaic cell. The pores provide opportunities to increase the surface area for contact between the two semiconductors, to align a p-type semiconductor at the junction, and to induce quantum confinement effects. These titania films with hexagonal phase are infiltrated with a hole conducting polymer, poly(3-hexylthiophene) (P3HT), in order to create a p-n junctions for organic-inorganic hybrid solar cells, by spin coating followed by thermal annealing. This assembly is hypothesized to give better photovoltaic performance compared to disordered or bicontinuous cubic nanopore arrangements; confinement in cylindrical nanopores is expected to provide

  4. CLiBE: a database of computed ligand binding energy for ligand-receptor complexes.

    PubMed

    Chen, X; Ji, Z L; Zhi, D G; Chen, Y Z

    2002-11-01

    Consideration of binding competitiveness of a drug candidate against natural ligands and other drugs that bind to the same receptor site may facilitate the rational development of a candidate into a potent drug. A strategy that can be applied to computer-aided drug design is to evaluate ligand-receptor interaction energy or other scoring functions of a designed drug with that of the relevant ligands known to bind to the same binding site. As a tool to facilitate such a strategy, a database of ligand-receptor interaction energy is developed from known ligand-receptor 3D structural entries in the Protein Databank (PDB). The Energy is computed based on a molecular mechanics force field that has been used in the prediction of therapeutic and toxicity targets of drugs. This database also contains information about ligand function and other properties and it can be accessed at http://xin.cz3.nus.edu.sg/group/CLiBE.asp. The computed energy components may facilitate the probing of the mode of action and other profiles of binding. A number of computed energies of some PDB ligand-receptor complexes in this database are studied and compared to experimental binding affinity. A certain degree of correlation between the computed energy and experimental binding affinity is found, which suggests that the computed energy may be useful in facilitating a qualitative analysis of drug binding competitiveness.

  5. An accurate and efficient computation method of the hydration free energy of a large, complex molecule.

    PubMed

    Yoshidome, Takashi; Ekimoto, Toru; Matubayasi, Nobuyuki; Harano, Yuichi; Kinoshita, Masahiro; Ikeguchi, Mitsunori

    2015-05-07

    The hydration free energy (HFE) is a crucially important physical quantity to discuss various chemical processes in aqueous solutions. Although an explicit-solvent computation with molecular dynamics (MD) simulations is a preferable treatment of the HFE, huge computational load has been inevitable for large, complex solutes like proteins. In the present paper, we propose an efficient computation method for the HFE. In our method, the HFE is computed as a sum of 〈UUV〉/2 (〈UUV〉 is the ensemble average of the sum of pair interaction energy between solute and water molecule) and the water reorganization term mainly reflecting the excluded volume effect. Since 〈UUV〉 can readily be computed through a MD of the system composed of solute and water, an efficient computation of the latter term leads to a reduction of computational load. We demonstrate that the water reorganization term can quantitatively be calculated using the morphometric approach (MA) which expresses the term as the linear combinations of the four geometric measures of a solute and the corresponding coefficients determined with the energy representation (ER) method. Since the MA enables us to finish the computation of the solvent reorganization term in less than 0.1 s once the coefficients are determined, the use of the MA enables us to provide an efficient computation of the HFE even for large, complex solutes. Through the applications, we find that our method has almost the same quantitative performance as the ER method with substantial reduction of the computational load.

  6. Exploiting Lipid Permutation Symmetry to Compute Membrane Remodeling Free Energies

    NASA Astrophysics Data System (ADS)

    Bubnis, Greg; Risselada, Herre Jelger; Grubmüller, Helmut

    2016-10-01

    A complete physical description of membrane remodeling processes, such as fusion or fission, requires knowledge of the underlying free energy landscapes, particularly in barrier regions involving collective shape changes, topological transitions, and high curvature, where Canham-Helfrich (CH) continuum descriptions may fail. To calculate these free energies using atomistic simulations, one must address not only the sampling problem due to high free energy barriers, but also an orthogonal sampling problem of combinatorial complexity stemming from the permutation symmetry of identical lipids. Here, we solve the combinatorial problem with a permutation reduction scheme to map a structural ensemble into a compact, nondegenerate subregion of configuration space, thereby permitting straightforward free energy calculations via umbrella sampling. We applied this approach, using a coarse-grained lipid model, to test the CH description of bending and found sharp increases in the bending modulus for curvature radii below 10 nm. These deviations suggest that an anharmonic bending term may be required for CH models to give quantitative energetics of highly curved states.

  7. Energy Drain by Computers Stifles Efforts at Cost Control

    ERIC Educational Resources Information Center

    Keller, Josh

    2009-01-01

    The high price of storing and processing data is hurting colleges and universities across the country. In response, some institutions are embracing greener technologies to keep costs down and help the environment. But compared with other industries, colleges and universities have been slow to understand the problem and to adopt energy-saving…

  8. Computational Research Challenges and Opportunities for the Optimization of Fossil Energy Power Generation System

    SciTech Connect

    Zitney, S.E.

    2007-06-01

    Emerging fossil energy power generation systems must operate with unprecedented efficiency and near-zero emissions, while optimizing profitably amid cost fluctuations for raw materials, finished products, and energy. To help address these challenges, the fossil energy industry will have to rely increasingly on the use advanced computational tools for modeling and simulating complex process systems. In this paper, we present the computational research challenges and opportunities for the optimization of fossil energy power generation systems across the plant lifecycle from process synthesis and design to plant operations. We also look beyond the plant gates to discuss research challenges and opportunities for enterprise-wide optimization, including planning, scheduling, and supply chain technologies.

  9. Solving difficult problems creatively: a role for energy optimised deterministic/stochastic hybrid computing

    PubMed Central

    Palmer, Tim N.; O’Shea, Michael

    2015-01-01

    How is the brain configured for creativity? What is the computational substrate for ‘eureka’ moments of insight? Here we argue that creative thinking arises ultimately from a synergy between low-energy stochastic and energy-intensive deterministic processing, and is a by-product of a nervous system whose signal-processing capability per unit of available energy has become highly energy optimised. We suggest that the stochastic component has its origin in thermal (ultimately quantum decoherent) noise affecting the activity of neurons. Without this component, deterministic computational models of the brain are incomplete. PMID:26528173

  10. Effectiveness of Conceptual Change Text-Oriented Instruction on Students' Understanding of Energy in Chemical Reactions

    ERIC Educational Resources Information Center

    Tastan, Ozgecan; Yalcinkaya, Eylem; Boz, Yezdan

    2008-01-01

    The aim of this study is to compare the effectiveness of conceptual change text instruction (CCT) in the context of energy in chemical reactions. The subjects of the study were 60, 10th grade students at a high school, who were in two different classes and taught by the same teacher. One of the classes was randomly selected as the experimental…

  11. Orientation of contravariant and covariant polymers and associated energy transfer in elasto-inertial turbulence

    NASA Astrophysics Data System (ADS)

    Horiuti, Kiyosi; Suzuki, Aoi

    2016-11-01

    It is generally assumed that the polymers in viscoelastic turbulence are advected affinely with the macroscopically-imposed deformation, while de Gennes (1986) hypothesized that stretched polymers may exhibit rigidity. We conduct assessment on this hypothesis in homogeneous isotropic turbulence by connecting mesoscopic Brownian description of elastic dumbbells to macroscopic DNS. The dumbbells are advected either affinely (contravariant) or non-affinely (covariant). We consider the elasto-inertial regime (Valente et al. 2014). Using the approximate solution of the constitutive equation for the polymer stress, we show that when the dumbbells are highly stretched, -SikSklSli term (Sij is strain-rate tensor) governs the transfer of solvent energy either to dissipation or to the elastic energy stored in the polymers. In the contravariant polymer, the elastic energy production term Pe < 0 and the dissipation production term Pɛ > 0 . The elastic energy is transferred backwardly into the solvent and dissipation is enhanced. In the covariant polymer, Pe > 0 and Pɛ > 0 . When the dumbbells are aligned with one of eigenvectors of Sij, Pe predominates Pɛ, and marked reduction of drag is achieved.

  12. Intrinsic gas production kinetics of selected intermediates in anaerobic filters for demand-orientated energy supply.

    PubMed

    Krümpel, Johannes Hagen; Illi, Lukas; Lemmer, Andreas

    2017-04-11

    As a consequence of a growing share of solar and wind power, recent research on biogas production highlighted a need for demand-orientated, flexible gas production to provide grid services and enable a decentralized stabilization of the electricity infrastructure. Two-staged anaerobic digestion is particularly suitable for shifting the methane production into times of higher demand due to the spatio-temporal separation of hydrolysis and methanogenesis. To provide a basis for predicting gas production in an anaerobic filter, kinetic parameters of gas production have been determined experimentally in this study. A new methodology is used, enabling their determination during continuous operation. An order in methane production rate could be established by comparing the half lives of methane production. The order was beginning with the fastest: acetic acid>ethanol>butyric acid>iso-butyric acid>valeric acid>propionic acid>1,2propanediol>lactic acid. However, the mixture of a natural hydrolysate from the acidification tank appeared to produce methane faster than all single components tested.

  13. Recovery Act - CAREER: Sustainable Silicon -- Energy-Efficient VLSI Interconnect for Extreme-Scale Computing

    SciTech Connect

    Chiang, Patrick

    2014-01-31

    The research goal of this CAREER proposal is to develop energy-efficient, VLSI interconnect circuits and systems that will facilitate future massively-parallel, high-performance computing. Extreme-scale computing will exhibit massive parallelism on multiple vertical levels, from thou­ sands of computational units on a single processor to thousands of processors in a single data center. Unfortunately, the energy required to communicate between these units at every level (on­ chip, off-chip, off-rack) will be the critical limitation to energy efficiency. Therefore, the PI's career goal is to become a leading researcher in the design of energy-efficient VLSI interconnect for future computing systems.

  14. Computing and Systems Applied in Support of Coordinated Energy, Environmental, and Climate Planning

    EPA Science Inventory

    This talk focuses on how Dr. Loughlin is applying Computing and Systems models, tools and methods to more fully understand the linkages among energy systems, environmental quality, and climate change. Dr. Loughlin will highlight recent and ongoing research activities, including: ...

  15. Energy Use and Power Levels in New Monitors and Personal Computers

    SciTech Connect

    Roberson, Judy A.; Homan, Gregory K.; Mahajan, Akshay; Nordman, Bruce; Webber, Carrie A.; Brown, Richard E.; McWhinney, Marla; Koomey, Jonathan G.

    2002-07-23

    Our research was conducted in support of the EPA ENERGY STAR Office Equipment program, whose goal is to reduce the amount of electricity consumed by office equipment in the U.S. The most energy-efficient models in each office equipment category are eligible for the ENERGY STAR label, which consumers can use to identify and select efficient products. As the efficiency of each category improves over time, the ENERGY STAR criteria need to be revised accordingly. The purpose of this study was to provide reliable data on the energy consumption of the newest personal computers and monitors that the EPA can use to evaluate revisions to current ENERGY STAR criteria as well as to improve the accuracy of ENERGY STAR program savings estimates. We report the results of measuring the power consumption and power management capabilities of a sample of new monitors and computers. These results will be used to improve estimates of program energy savings and carbon emission reductions, and to inform rev isions of the ENERGY STAR criteria for these products. Our sample consists of 35 monitors and 26 computers manufactured between July 2000 and October 2001; it includes cathode ray tube (CRT) and liquid crystal display (LCD) monitors, Macintosh and Intel-architecture computers, desktop and laptop computers, and integrated computer systems, in which power consumption of the computer and monitor cannot be measured separately. For each machine we measured power consumption when off, on, and in each low-power level. We identify trends in and opportunities to reduce power consumption in new personal computers and monitors. Our results include a trend among monitor manufacturers to provide a single very low low-power level, well below the current ENERGY STAR criteria for sleep power consumption. These very low sleep power results mean that energy consumed when monitors are off or in active use has become more important in terms of contribution to the overall unit energy consumption (UEC

  16. Computational Investigation of Impact Energy Absorption Capability of Polyurea Coatings via Deformation-Induced Glass Transition

    DTIC Science & Technology

    2010-01-01

    homepage: www.e lsev ier .com/ locate /msea Computational investigation of impact energy absorption capability of polyurea coatings via deformation-induced...Keywords: Polyurea Computational analysis Glass transition Blast/impact energy absorption coating a b s t r a c t A number of experimental investigations...reported in the open literature have indicated that the applica- tion of polyurea coatings can substantially improve blast and ballistic impact

  17. Computer Simulation of a Traveling-Wave Direct Energy Converter

    NASA Astrophysics Data System (ADS)

    Katayama, Hideaki; Sato, Kunihiro; Miyawaki, Fujio

    Beam-circuit code is presented to simulate a Traveling-Wave Direct Energy Converter (TWDEC), which recovers the energy of fusion protons escaping from a FRC/D3He fusion reactor. A transmission line loop for propagation of the electrostatic traveling wave is designed using lumped constant elements L.C.R. Electrostatic coupling between proton beam and circuits is treated by directly solving Poisson’s equation. Circuit equations are transformed to temporal finite-difference equations, which are solved following the leap-flog scheme. Simulation results display desirable performance characteristics. Traveling wave with a fixed frequency is excited spontaneously without any external power supply. The wave is kept its equilibrium state under loading, and the wave is stable to variation of the load.

  18. On-line computer system for use with low- energy nuclear physics experiments is reported

    NASA Technical Reports Server (NTRS)

    Gemmell, D. S.

    1969-01-01

    Computer program handles data from low-energy nuclear physics experiments which utilize the ND-160 pulse-height analyzer and the PHYLIS computing system. The program allows experimenters to choose from about 50 different basic data-handling functions and to prescribe the order in which these functions will be performed.

  19. Minimizing the Free Energy: A Computer Method for Teaching Chemical Equilibrium Concepts.

    ERIC Educational Resources Information Center

    Heald, Emerson F.

    1978-01-01

    Presents a computer method for teaching chemical equilibrium concepts using material balance conditions and the minimization of the free energy. Method for the calculation of chemical equilibrium, the computer program used to solve equilibrium problems and applications of the method are also included. (HM)

  20. Monte Carlo Computational Modeling of the Energy Dependence of Atomic Oxygen Undercutting of Protected Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Stueber, Thomas J.; Norris, Mary Jo

    1998-01-01

    A Monte Carlo computational model has been developed which simulates atomic oxygen attack of protected polymers at defect sites in the protective coatings. The parameters defining how atomic oxygen interacts with polymers and protective coatings as well as the scattering processes which occur have been optimized to replicate experimental results observed from protected polyimide Kapton on the Long Duration Exposure Facility (LDEF) mission. Computational prediction of atomic oxygen undercutting at defect sites in protective coatings for various arrival energies was investigated. The atomic oxygen undercutting energy dependence predictions enable one to predict mass loss that would occur in low Earth orbit, based on lower energy ground laboratory atomic oxygen beam systems. Results of computational model prediction of undercut cavity size as a function of energy and defect size will be presented to provide insight into expected in-space mass loss of protected polymers with protective coating defects based on lower energy ground laboratory testing.

  1. Reverse energy partitioning-An efficient algorithm for computing the density of states, partition functions, and free energy of solids.

    PubMed

    Do, Hainam; Wheatley, Richard J

    2016-08-28

    A robust and model free Monte Carlo simulation method is proposed to address the challenge in computing the classical density of states and partition function of solids. Starting from the minimum configurational energy, the algorithm partitions the entire energy range in the increasing energy direction ("upward") into subdivisions whose integrated density of states is known. When combined with the density of states computed from the "downward" energy partitioning approach [H. Do, J. D. Hirst, and R. J. Wheatley, J. Chem. Phys. 135, 174105 (2011)], the equilibrium thermodynamic properties can be evaluated at any temperature and in any phase. The method is illustrated in the context of the Lennard-Jones system and can readily be extended to other molecular systems and clusters for which the structures are known.

  2. Study of shock shape and strength as a function of plasma energy using background oriented schlieren and shadowgraph

    NASA Astrophysics Data System (ADS)

    Singh, Bhavini; Rajendran, Lalit; Giarra, Matthew; Bane, Sally; Vlachos, Pavlos

    2016-11-01

    The formation of a spark is a random, chaotic process. The flow field generated by this spark can be used in flow control and plasma assisted combustion applications. In order to understand the flow field some time after spark discharge (approximately 1 microsecond), it is important to observe the shape and strength of the shockwave immediately following the plasma discharge. It is also important to understand the effect that the energy deposited in the spark gap has on the shock strength and shock shape. We therefore propose a background oriented schlieren (BOS) technique to measure density gradients associated with the spark discharge and hence quantify shock strength. Simultaneous shadowgraph measurements will be used to observe the shape of the shock and compare it with the reconstructed density gradients obtained from BOS measurements.

  3. Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions

    SciTech Connect

    Schmidt, Burkhard; Friedrich, Bretislav

    2014-02-14

    We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables – such as alignment and orientation cosines – in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

  4. Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions

    NASA Astrophysics Data System (ADS)

    Schmidt, Burkhard; Friedrich, Bretislav

    2014-02-01

    We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables - such as alignment and orientation cosines - in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

  5. Effects of excluded volume and correlated molecular orientations on Förster resonance energy transfer in liquid water

    SciTech Connect

    Yang, Mino

    2014-04-14

    Förster theory for the survival probability of excited chromophores is generalized to include the effects of excluded volume and orientation correlation in the molecular distribution. An analytical expression for survival probability was derived and written in terms of a few simple elementary functions. Because of the excluded volume, the survival probability exhibits exponential decay at early times and stretched exponential decay at later times. Experimental schemes to determine the size of the molecular excluded volume are suggested. With the present generalization of theory, we analyzed vibrational resonance energy transfer kinetics in neat water. Excluded volume effects prove to be important and slow down the kinetics at early times. The majority of intermolecular resonance energy transfer was found to occur with exponential kinetics, as opposed to the stretched exponential behavior predicted by Förster theory. Quantum yields of intra-molecular vibrational relaxation, intra-, and intermolecular energy transfer were calculated to be 0.413, 0.167, and 0.420, respectively.

  6. Solar energy conversion systems engineering and economic analysis radiative energy input/thermal electric output computation. Volume III

    SciTech Connect

    Russo, G.

    1982-09-01

    The direct energy flux analytical model, an analysis of the results, and a brief description of a non-steady state model of a thermal solar energy conversion system implemented on a code, SIRR2, as well as the coupling of CIRR2 which computes global solar flux on a collector and SIRR2 are presented. It is shown how the CIRR2 and, mainly, the SIRR2 codes may be used for a proper design of a solar collector system. (LEW)

  7. Computer aided optimal design of compressed air energy storage systems

    NASA Astrophysics Data System (ADS)

    Ahrens, F. W.; Sharma, A.; Ragsdell, K. M.

    1980-07-01

    An automated procedure for the design of Compressed Air Energy Storage (CAES) systems is presented. The procedure relies upon modern nonlinear programming algorithms, decomposition theory, and numerical models of the various system components. Two modern optimization methods are employed; BIAS, a Method of Multipliers code and OPT, a Generalized Reduced Gradient code. The procedure is demonstrated by the design of a CAES facility employing the Media, Illinois Galesville aquifer as the reservoir. The methods employed produced significant reduction in capital and operating cost, and in number of aquifer wells required.

  8. Theoretical studies of potential energy surfaces and computational methods

    SciTech Connect

    Shepard, R.

    1993-12-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  9. Emotion recognition (sometimes) depends on horizontal orientations

    PubMed Central

    Huynh, Carol M; Balas, Benjamin

    2014-01-01

    Face recognition depends critically on horizontal orientations (Goffaux & Dakin, 2010). Face images that lack horizontal features are harder to recognize than those that have that information preserved. Presently, we asked if facial emotional recognition also exhibits this dependency by asking observers to categorize orientation-filtered happy and sad expressions. Furthermore, we aimed to dissociate image-based orientation energy from object-based orientation by rotating images 90-degrees in the picture-plane. In our first experiment, we showed that the perception of emotional expression does depend on horizontal orientations and that object-based orientation constrained performance more than image-based orientation. In Experiment 2 we showed that mouth openness (i.e. open versus closed-mouths) also influenced the emotion-dependent reliance on horizontal information. Lastly, we describe a simple computational analysis that demonstrates that the impact of mouth openness was not predicted by variation in the distribution of orientation energy across horizontal and vertical orientation bands. Overall, our results suggest that emotion recognition does largely depend on horizontal information defined relative to the face, but that this bias is modulated by multiple factors that introduce variation in appearance across and within distinct emotions. PMID:24664854

  10. Factors Affecting Energy Barriers for Pyramidal Inversion in Amines and Phosphines: A Computational Chemistry Lab Exercise

    ERIC Educational Resources Information Center

    Montgomery, Craig D.

    2013-01-01

    An undergraduate exercise in computational chemistry that investigates the energy barrier for pyramidal inversion of amines and phosphines is presented. Semiempirical calculations (PM3) of the ground-state and transition-state energies for NR[superscript 1]R[superscript 2]R[superscript 3] and PR[superscript 1]R[superscript 2]R[superscript 3] allow…

  11. Spin-neurons: A possible path to energy-efficient neuromorphic computers

    NASA Astrophysics Data System (ADS)

    Sharad, Mrigank; Fan, Deliang; Roy, Kaushik

    2013-12-01

    Recent years have witnessed growing interest in the field of brain-inspired computing based on neural-network architectures. In order to translate the related algorithmic models into powerful, yet energy-efficient cognitive-computing hardware, computing-devices beyond CMOS may need to be explored. The suitability of such devices to this field of computing would strongly depend upon how closely their physical characteristics match with the essential computing primitives employed in such models. In this work, we discuss the rationale of applying emerging spin-torque devices for bio-inspired computing. Recent spin-torque experiments have shown the path to low-current, low-voltage, and high-speed magnetization switching in nano-scale magnetic devices. Such magneto-metallic, current-mode spin-torque switches can mimic the analog summing and "thresholding" operation of an artificial neuron with high energy-efficiency. Comparison with CMOS-based analog circuit-model of a neuron shows that "spin-neurons" (spin based circuit model of neurons) can achieve more than two orders of magnitude lower energy and beyond three orders of magnitude reduction in energy-delay product. The application of spin-neurons can therefore be an attractive option for neuromorphic computers of future.

  12. Spin-neurons: A possible path to energy-efficient neuromorphic computers

    SciTech Connect

    Sharad, Mrigank; Fan, Deliang; Roy, Kaushik

    2013-12-21

    Recent years have witnessed growing interest in the field of brain-inspired computing based on neural-network architectures. In order to translate the related algorithmic models into powerful, yet energy-efficient cognitive-computing hardware, computing-devices beyond CMOS may need to be explored. The suitability of such devices to this field of computing would strongly depend upon how closely their physical characteristics match with the essential computing primitives employed in such models. In this work, we discuss the rationale of applying emerging spin-torque devices for bio-inspired computing. Recent spin-torque experiments have shown the path to low-current, low-voltage, and high-speed magnetization switching in nano-scale magnetic devices. Such magneto-metallic, current-mode spin-torque switches can mimic the analog summing and “thresholding” operation of an artificial neuron with high energy-efficiency. Comparison with CMOS-based analog circuit-model of a neuron shows that “spin-neurons” (spin based circuit model of neurons) can achieve more than two orders of magnitude lower energy and beyond three orders of magnitude reduction in energy-delay product. The application of spin-neurons can therefore be an attractive option for neuromorphic computers of future.

  13. Estimation of free-energy differences from computed work distributions: an application of Jarzynski's equality.

    PubMed

    Echeverria, Ignacia; Amzel, L Mario

    2012-09-13

    Equilibrium free-energy differences can be computed from nonequilibrium molecular dynamics (MD) simulations using Jarzynski's equality (Jarzynski, C. Phys. Rev. Lett.1997, 78, 2690) by combining a large set of independent trajectories (path ensemble). Here we present the multistep trajectory combination (MSTC) method to compute free-energy differences, which by combining trajectories significantly reduces the number of trajectories necessary to generate a representative path ensemble. This method generates well-sampled work distributions, even for large systems, by combining parts of a relatively small number of trajectories carried out in steps. To assess the efficiency of the MSTC method, we derived analytical expressions and used them to compute the bias and the variance of the free-energy estimates along with numerically calculated values. We show that the MSTC method significantly reduces both the bias and variance of the free-energy estimates compared to the estimates obtained using single-step trajectories. In addition, because in the MSTC method the process is divided into steps, it is feasible to compute the reverse transition. By combining the forward and reverse processes, the free-energy difference can be computed using the Crooks' fluctuation theorem (Crooks, G. E. J. Stat. Phys.1998, 90, 1481 and Crooks, G. E. Phys. Rev. E 2000, 61, 2361) or Bennett's acceptance ratio (Bennett, C. H. J. Comput. Phys. 1976, 22, 245), which further reduces the bias and variance of the estimates.

  14. Energy-Efficient Computational Chemistry: Comparison of x86 and ARM Systems.

    PubMed

    Keipert, Kristopher; Mitra, Gaurav; Sunriyal, Vaibhav; Leang, Sarom S; Sosonkina, Masha; Rendell, Alistair P; Gordon, Mark S

    2015-11-10

    The computational efficiency and energy-to-solution of several applications using the GAMESS quantum chemistry suite of codes is evaluated for 32-bit and 64-bit ARM-based computers, and compared to an x86 machine. The x86 system completes all benchmark computations more quickly than either ARM system and is the best choice to minimize time to solution. The ARM64 and ARM32 computational performances are similar to each other for Hartree-Fock and density functional theory energy calculations. However, for memory-intensive second-order perturbation theory energy and gradient computations the lower ARM32 read/write memory bandwidth results in computation times as much as 86% longer than on the ARM64 system. The ARM32 system is more energy efficient than the x86 and ARM64 CPUs for all benchmarked methods, while the ARM64 CPU is more energy efficient than the x86 CPU for some core counts and molecular sizes.

  15. A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus

    SciTech Connect

    Raustad, Richard A.

    2013-01-01

    This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

  16. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  17. Impact of office productivity cloud computing on energy consumption and greenhouse gas emissions.

    PubMed

    Williams, Daniel R; Tang, Yinshan

    2013-05-07

    Cloud computing is usually regarded as being energy efficient and thus emitting less greenhouse gases (GHG) than traditional forms of computing. When the energy consumption of Microsoft's cloud computing Office 365 (O365) and traditional Office 2010 (O2010) software suites were tested and modeled, some cloud services were found to consume more energy than the traditional form. The developed model in this research took into consideration the energy consumption at the three main stages of data transmission; data center, network, and end user device. Comparable products from each suite were selected and activities were defined for each product to represent a different computing type. Microsoft provided highly confidential data for the data center stage, while the networking and user device stages were measured directly. A new measurement and software apportionment approach was defined and utilized allowing the power consumption of cloud services to be directly measured for the user device stage. Results indicated that cloud computing is more energy efficient for Excel and Outlook which consumed less energy and emitted less GHG than the standalone counterpart. The power consumption of the cloud based Outlook (8%) and Excel (17%) was lower than their traditional counterparts. However, the power consumption of the cloud version of Word was 17% higher than its traditional equivalent. A third mixed access method was also measured for Word which emitted 5% more GHG than the traditional version. It is evident that cloud computing may not provide a unified way forward to reduce energy consumption and GHG. Direct conversion from the standalone package into the cloud provision platform can now consider energy and GHG emissions at the software development and cloud service design stage using the methods described in this research.

  18. Connecting free energy surfaces in implicit and explicit solvent: an efficient method to compute conformational and solvation free energies.

    PubMed

    Deng, Nanjie; Zhang, Bin W; Levy, Ronald M

    2015-06-09

    The ability to accurately model solvent effects on free energy surfaces is important for understanding many biophysical processes including protein folding and misfolding, allosteric transitions, and protein–ligand binding. Although all-atom simulations in explicit solvent can provide an accurate model for biomolecules in solution, explicit solvent simulations are hampered by the slow equilibration on rugged landscapes containing multiple basins separated by barriers. In many cases, implicit solvent models can be used to significantly speed up the conformational sampling; however, implicit solvent simulations do not fully capture the effects of a molecular solvent, and this can lead to loss of accuracy in the estimated free energies. Here we introduce a new approach to compute free energy changes in which the molecular details of explicit solvent simulations are retained while also taking advantage of the speed of the implicit solvent simulations. In this approach, the slow equilibration in explicit solvent, due to the long waiting times before barrier crossing, is avoided by using a thermodynamic cycle which connects the free energy basins in implicit solvent and explicit solvent using a localized decoupling scheme. We test this method by computing conformational free energy differences and solvation free energies of the model system alanine dipeptide in water. The free energy changes between basins in explicit solvent calculated using fully explicit solvent paths agree with the corresponding free energy differences obtained using the implicit/explicit thermodynamic cycle to within 0.3 kcal/mol out of ∼3 kcal/mol at only ∼8% of the computational cost. We note that WHAM methods can be used to further improve the efficiency and accuracy of the implicit/explicit thermodynamic cycle.

  19. Large Scale Computing and Storage Requirements for Basic Energy Sciences Research

    SciTech Connect

    Gerber, Richard; Wasserman, Harvey

    2011-03-31

    The National Energy Research Scientific Computing Center (NERSC) is the leading scientific computing facility supporting research within the Department of Energy's Office of Science. NERSC provides high-performance computing (HPC) resources to approximately 4,000 researchers working on about 400 projects. In addition to hosting large-scale computing facilities, NERSC provides the support and expertise scientists need to effectively and efficiently use HPC systems. In February 2010, NERSC, DOE's Office of Advanced Scientific Computing Research (ASCR) and DOE's Office of Basic Energy Sciences (BES) held a workshop to characterize HPC requirements for BES research through 2013. The workshop was part of NERSC's legacy of anticipating users future needs and deploying the necessary resources to meet these demands. Workshop participants reached a consensus on several key findings, in addition to achieving the workshop's goal of collecting and characterizing computing requirements. The key requirements for scientists conducting research in BES are: (1) Larger allocations of computational resources; (2) Continued support for standard application software packages; (3) Adequate job turnaround time and throughput; and (4) Guidance and support for using future computer architectures. This report expands upon these key points and presents others. Several 'case studies' are included as significant representative samples of the needs of science teams within BES. Research teams scientific goals, computational methods of solution, current and 2013 computing requirements, and special software and support needs are summarized in these case studies. Also included are researchers strategies for computing in the highly parallel, 'multi-core' environment that is expected to dominate HPC architectures over the next few years. NERSC has strategic plans and initiatives already underway that address key workshop findings. This report includes a brief summary of those relevant to issues

  20. Benefits of texture analysis of dual energy CT for Computer-Aided pulmonary embolism detection.

    PubMed

    Foncubierta-Rodríguez, Antonio; Jiménez del Toro, Óscar Alfonso; Platon, Alexandra; Poletti, Pierre-Alexandre; Müller, Henning; Depeursinge, Adrien

    2013-01-01

    Pulmonary embolism is an avoidable cause of death if treated immediately but delays in diagnosis and treatment lead to an increased risk. Computer-assisted image analysis of both unenhanced and contrast-enhanced computed tomography (CT) have proven useful for diagnosis of pulmonary embolism. Dual energy CT provides additional information over the standard single energy scan by generating four-dimensional (4D) data, in our case with 11 energy levels in 3D. In this paper a 4D texture analysis method capable of detecting pulmonary embolism in dual energy CT is presented. The method uses wavelet-based visual words together with an automatic geodesic-based region of interest detection algorithm to characterize the texture properties of each lung lobe. Results show an increase in performance with respect to the single energy CT analysis, as well as an accuracy gain compared to preliminary work on a small dataset.

  1. Ermod: fast and versatile computation software for solvation free energy with approximate theory of solutions.

    PubMed

    Sakuraba, Shun; Matubayasi, Nobuyuki

    2014-08-05

    ERmod is a software package to efficiently and approximately compute the solvation free energy using the method of energy representation. Molecular simulation is to be conducted at two condensed-phase systems of the solution of interest and the reference solvent with test-particle insertion of the solute. The subprogram ermod in ERmod then provides a set of energy distribution functions from the simulation trajectories, and another subprogram slvfe determines the solvation free energy from the distribution functions through an approximate functional. This article describes the design and implementation of ERmod, and illustrates its performance in solvent water for two organic solutes and two protein solutes. Actually, the free-energy computation with ERmod is not restricted to the solvation in homogeneous medium such as fluid and polymer and can treat the binding into weakly ordered system with nano-inhomogeneity such as micelle and lipid membrane. ERmod is available on web at http://sourceforge.net/projects/ermod.

  2. The Energy Systems Optimization Computer Program /ESOP/ developed for Modular Integrated Utility Systems /MIUS/ analysis

    NASA Technical Reports Server (NTRS)

    Ferden, S. L.; Rochelle, W. C.; Stallings, R. D.; Brandli, A. E.; Lively, C. F., Jr.

    1974-01-01

    A significant energy and cost savings can be obtained by integrating various utility services (space heating and cooling, electrical power generation, solid waste disposal, potable water, and waste water treatment) into a single unit which provides buildings or groups of buildings with these services. This paper presents a description of a computer program, called the Energy Systems Optimization Program (ESOP). This program predicts the loads, energy requirements, equipment sizes, and life-cycle costs of alternative methods of meeting these utility requirements. The program has been used extensively for performing energy analyses of Modular Integrated Utility Systems (MIUS).

  3. Ultra-low-energy non-volatile straintronic computing using single multiferroic composites

    NASA Astrophysics Data System (ADS)

    Roy, Kuntal

    2013-10-01

    The primary impediment to continued downscaling of traditional charge-based electronic devices in accordance with Moore's law is the excessive energy dissipation that takes place in the device during switching of bits. One very promising solution is to utilize multiferroic heterostructures, comprised of a single-domain magnetostrictive nanomagnet strain-coupled to a piezoelectric layer, in which the magnetization can be switched between its two stable states while dissipating minuscule amount of energy. However, no efficient and viable means of computing is proposed so far. Here we show that such single multiferroic composites can act as universal logic gates for computing purposes, which we demonstrate by solving the stochastic Landau-Lifshitz-Gilbert equation of magnetization dynamics in the presence of room-temperature thermal fluctuations. The proposed concept can overwhelmingly simplify the design of large-scale circuits and portend a highly dense yet an ultra-low-energy computing paradigm for our future information processing systems.

  4. Optimization of energy level for coronary angiography with dual-energy and dual-source computed tomography.

    PubMed

    Okayama, Satoshi; Seno, Ayako; Soeda, Tsunenari; Takami, Yasuhiro; Kawakami, Rika; Somekawa, Satoshi; Ishigami, Ken-Ichi; Takeda, Yukiji; Kawata, Hiroyuki; Horii, Manabu; Uemura, Shiro; Saito, Yoshihiko

    2012-04-01

    Dual-energy computed tomography (DE-CT) uses polyenergetic X-rays at 100- and 140-kVp tube energy, and generates 120-kVp composite images that are referred to as polyenergetic images (PEIs). Moreover, DE-CT can produce monoenergetic images (MEIs) at any effective energy level. We evaluated whether the image quality of coronary angiography is improved by optimizing the energy levels of DE-CT. We retrospectively evaluated data sets obtained from 24 consecutive patients using cardiac DE-CT at 100- and 140-kVp tube energy with a dual-source scanner. Signal-to-noise ratios (SNRs) were evaluated in the left ascending coronary artery in PEIs, and in MEIs reconstructed at 40, 50, 60, 70, 80, 90, 100, 130, 160 and 190 keV. Energy levels of 100, 120 and 140 kVp generated the highest SNRs in PEIs from 10, 12 and 2 patients, respectively, at 60, 70 and 80 keV in MEIs from 2, 10 and 10 patients, respectively, and at 90 and 100 keV in those from one patient each. Optimization of the energy level for each patient increased the SNR by 16.6% in PEIs (P < 0.0001) and by 18.2% in MEIs (P < 0.05), compared with 120-kVp composite images. The image quality of coronary angiography using DE-CT can be improved by optimizing the energy level for individual patients.

  5. A computation method of dual-energy x-ray imaging

    NASA Astrophysics Data System (ADS)

    Mou, Xuanqin; Tang, Shaojie; Hong, Wei

    2006-03-01

    Dual-energy X-ray imaging is an important method of medical imaging, capable of not only obtaining spatial information of imaging object but also disclosing its chemical components, and has many applications in clinic. The current computation methods of dual-energy imaging are still based on the model of mono-energy spectrum imaging with some linear calibration, while they are incapable to reflect correctly the physical characteristics of dual-energy imaging and obstruct deeper research in this field. The article presents a new medical X-ray imaging model in accordance with physics of imaging and its corresponding computational method. The computation process includes two steps: first, to compute two attenuation parameters that have clear physical meaning: equivalent electron density and attenuation parameter of photoemission; then to compute the components of high- and low-density mass through a group of simple equation with two variables. Experiments showed that such method has quite a satisfactory precision in theory, that is, the solutions of parameters under different exposure voltages and thickness of tissue for several main tissues of human body are much low in deviations, whose quotient of standard deviation divided by mean are mostly under 0.1%, and at most 0.32%. The method provides not only a new computational way for dual-energy X-ray imaging, but also a feasible analysis for its nature. In addition, the method can be used to linearly rectify data of dual-energy CT and analyze the chemical component of reconstructed object by means of parameters clear in physics.

  6. Free energy minimization to predict RNA secondary structures and computational RNA design.

    PubMed

    Churkin, Alexander; Weinbrand, Lina; Barash, Danny

    2015-01-01

    Determining the RNA secondary structure from sequence data by computational predictions is a long-standing problem. Its solution has been approached in two distinctive ways. If a multiple sequence alignment of a collection of homologous sequences is available, the comparative method uses phylogeny to determine conserved base pairs that are more likely to form as a result of billions of years of evolution than by chance. In the case of single sequences, recursive algorithms that compute free energy structures by using empirically derived energy parameters have been developed. This latter approach of RNA folding prediction by energy minimization is widely used to predict RNA secondary structure from sequence. For a significant number of RNA molecules, the secondary structure of the RNA molecule is indicative of its function and its computational prediction by minimizing its free energy is important for its functional analysis. A general method for free energy minimization to predict RNA secondary structures is dynamic programming, although other optimization methods have been developed as well along with empirically derived energy parameters. In this chapter, we introduce and illustrate by examples the approach of free energy minimization to predict RNA secondary structures.

  7. A dual-energy approach for improvement of the measurement consistency in computed tomography

    NASA Astrophysics Data System (ADS)

    Jansson, Anton; Pejryd, Lars

    2016-11-01

    Computed tomography is increasingly adopted by industries for metrological and material evaluation. The technology enables new measurement possibilities, while also challenging old measurement methods in their established territories. There are, however, uncertainties related with the computed tomography method. Investigation of multi-material components with, in particular, varying material thickness can result in unreliable measurements. In this paper the effects of multi-materials, and differing material thickness, on computed tomography measurement consistency has been studied. The aim of the study was to identify measurement inconsistencies and attempt to correct these with a dual-energy computed tomography approach. In this pursuit, a multi-material phantom was developed, containing reliable measurement points and custom-ability with regards to material combinations. A dual-energy method was developed and implemented using sequential acquisition and pre-reconstruction fusing of projections. It was found that measurements made on the multi-material phantom with a single computed tomography scan were highly inconsistent. It was also found that the dual-energy approach was able to reduce the measurement inconsistencies. However, more work is required with the automation of the dual-energy approach presented in this paper since it is highly operator dependant.

  8. Cloud computing for energy management in smart grid - an application survey

    NASA Astrophysics Data System (ADS)

    Naveen, P.; Kiing Ing, Wong; Kobina Danquah, Michael; Sidhu, Amandeep S.; Abu-Siada, Ahmed

    2016-03-01

    The smart grid is the emerging energy system wherein the application of information technology, tools and techniques that make the grid run more efficiently. It possesses demand response capacity to help balance electrical consumption with supply. The challenges and opportunities of emerging and future smart grids can be addressed by cloud computing. To focus on these requirements, we provide an in-depth survey on different cloud computing applications for energy management in the smart grid architecture. In this survey, we present an outline of the current state of research on smart grid development. We also propose a model of cloud based economic power dispatch for smart grid.

  9. Report of the Subpanel on Theoretical Computing of the High Energy Physics Advisory Panel

    SciTech Connect

    Not Available

    1984-09-01

    The Subpanel on Theoretical Computing of the High Energy Physics Advisory Panel (HEPAP) was formed in July 1984 to make recommendations concerning the need for state-of-the-art computing for theoretical studies. The specific Charge to the Subpanel is attached as Appendix A, and the full membership is listed in Appendix B. For the purposes of this study, theoretical computing was interpreted as encompassing both investigations in the theory of elementary particles and computation-intensive aspects of accelerator theory and design. Many problems in both areas are suited to realize the advantages of vectorized processing. The body of the Subpanel Report is organized as follows. The Introduction, Section I, explains some of the goals of computational physics as it applies to elementary particle theory and accelerator design. Section II reviews the availability of mainframe supercomputers to researchers in the United States, in Western Europe, and in Japan. Other promising approaches to large-scale computing are summarized in Section III. Section IV details the current computing needs for problems in high energy theory, and for beam dynamics studies. The Subpanel Recommendations appear in Section V. The Appendices attached to this Report give the Charge to the Subpanel, the Subpanel membership, and some background information on the financial implications of establishing a supercomputer center.

  10. Computational chemistry for graphene-based energy applications: progress and challenges

    NASA Astrophysics Data System (ADS)

    Hughes, Zak E.; Walsh, Tiffany R.

    2015-04-01

    Research in graphene-based energy materials is a rapidly growing area. Many graphene-based energy applications involve interfacial processes. To enable advances in the design of these energy materials, such that their operation, economy, efficiency and durability is at least comparable with fossil-fuel based alternatives, connections between the molecular-scale structure and function of these interfaces are needed. While it is experimentally challenging to resolve this interfacial structure, molecular simulation and computational chemistry can help bridge these gaps. In this Review, we summarise recent progress in the application of computational chemistry to graphene-based materials for fuel cells, batteries, photovoltaics and supercapacitors. We also outline both the bright prospects and emerging challenges these techniques face for application to graphene-based energy materials in future.

  11. Computational chemistry for graphene-based energy applications: progress and challenges.

    PubMed

    Hughes, Zak E; Walsh, Tiffany R

    2015-04-28

    Research in graphene-based energy materials is a rapidly growing area. Many graphene-based energy applications involve interfacial processes. To enable advances in the design of these energy materials, such that their operation, economy, efficiency and durability is at least comparable with fossil-fuel based alternatives, connections between the molecular-scale structure and function of these interfaces are needed. While it is experimentally challenging to resolve this interfacial structure, molecular simulation and computational chemistry can help bridge these gaps. In this Review, we summarise recent progress in the application of computational chemistry to graphene-based materials for fuel cells, batteries, photovoltaics and supercapacitors. We also outline both the bright prospects and emerging challenges these techniques face for application to graphene-based energy materials in future.

  12. Path Integral Computation of Quantum Free Energy Differences Due to Alchemical Transformations Involving Mass and Potential.

    PubMed

    Pérez, Alejandro; von Lilienfeld, O Anatole

    2011-08-09

    Thermodynamic integration, perturbation theory, and λ-dynamics methods were applied to path integral molecular dynamics calculations to investigate free energy differences due to "alchemical" transformations. Several estimators were formulated to compute free energy differences in solvable model systems undergoing changes in mass and/or potential. Linear and nonlinear alchemical interpolations were used for the thermodynamic integration. We find improved convergence for the virial estimators, as well as for the thermodynamic integration over nonlinear interpolation paths. Numerical results for the perturbative treatment of changes in mass and electric field strength in model systems are presented. We used thermodynamic integration in ab initio path integral molecular dynamics to compute the quantum free energy difference of the isotope transformation in the Zundel cation. The performance of different free energy methods is discussed.

  13. Energy conservation and analysis and evaluation. [specifically at Slidell Computer Complex

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The survey assembled and made recommendations directed at conserving utilities and reducing the use of energy at the Slidell Computer Complex. Specific items included were: (1) scheduling and controlling the use of gas and electricity, (2) building modifications to reduce energy, (3) replacement of old, inefficient equipment, (4) modifications to control systems, (5) evaluations of economizer cycles in HVAC systems, and (6) corrective settings for thermostats, ductstats, and other temperature and pressure control devices.

  14. Accurate ab initio potential energy computations for the H sub 4 system: Tests of some analytic potential energy surfaces

    SciTech Connect

    Boothroyd, A.I. ); Dove, J.E.; Keogh, W.J. ); Martin, P.G. ); Peterson, M.R. )

    1991-09-15

    The interaction potential energy surface (PES) of H{sub 4} is of great importance for quantum chemistry, as a test case for molecule--molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H{sub 2} in molecular clouds, at densities too low to be accessible experimentally. Accurate {ital ab} {ital initio} energies were computed for 6046 conformations of H{sub 4}, using a multiple reference (single and) double excitation configuration interaction (MRD-CI) program. Both systematic and random'' errors were estimated to have an rms size of 0.6 mhartree, for a total rms error of about 0.9 mhartree (or 0.55 kcal/mol) in the final {ital ab} {ital initio} energy values. It proved possible to include in a self-consistent way {ital ab} {ital initio} energies calculated by Schwenke, bringing the number of H{sub 4} conformations to 6101. {ital Ab} {ital initio} energies were also computed for 404 conformations of H{sub 3}; adding {ital ab} {ital initio} energies calculated by other authors yielded a total of 772 conformations of H{sub 3}. (The H{sub 3} results, and an improved analytic PES for H{sub 3}, are reported elsewhere.) {ital Ab} {ital initio} energies are tabulated in this paper only for a sample of H{sub 4} conformations; a full list of all 6101 conformations of H{sub 4} (and 772 conformations of H{sub 3} ) is available from Physics Auxiliary Publication Service (PAPS), or from the authors.

  15. Evaluation of linear measurements of implant sites based on head orientation during acquisition: An ex vivo study using cone-beam computed tomography

    PubMed Central

    Sabban, Hanadi; Mahdian, Mina; Dhingra, Ajay; Lurie, Alan G.

    2015-01-01

    Purpose This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Results Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Conclusion Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension. PMID:26125001

  16. Computational Plasma Physics at the Bleeding Edge: Simulating Kinetic Turbulence Dynamics in Fusion Energy Sciences

    NASA Astrophysics Data System (ADS)

    Tang, William

    2013-04-01

    Advanced computing is generally recognized to be an increasingly vital tool for accelerating progress in scientific research in the 21st Century. The imperative is to translate the combination of the rapid advances in super-computing power together with the emergence of effective new algorithms and computational methodologies to help enable corresponding increases in the physics fidelity and the performance of the scientific codes used to model complex physical systems. If properly validated against experimental measurements and verified with mathematical tests and computational benchmarks, these codes can provide more reliable predictive capability for the behavior of complex systems, including fusion energy relevant high temperature plasmas. The magnetic fusion energy research community has made excellent progress in developing advanced codes for which computer run-time and problem size scale very well with the number of processors on massively parallel supercomputers. A good example is the effective usage of the full power of modern leadership class computational platforms from the terascale to the petascale and beyond to produce nonlinear particle-in-cell simulations which have accelerated progress in understanding the nature of plasma turbulence in magnetically-confined high temperature plasmas. Illustrative results provide great encouragement for being able to include increasingly realistic dynamics in extreme-scale computing campaigns to enable predictive simulations with unprecedented physics fidelity. Some illustrative examples will be presented of the algorithmic progress from the magnetic fusion energy sciences area in dealing with low memory per core extreme scale computing challenges for the current top 3 supercomputers worldwide. These include advanced CPU systems (such as the IBM-Blue-Gene-Q system and the Fujitsu K Machine) as well as the GPU-CPU hybrid system (Titan).

  17. Exploring the controls of soil biogeochemistry in a restored coastal wetland using object-oriented computer simulations of uptake kinetics and thermodynamic optimization in batch reactors

    NASA Astrophysics Data System (ADS)

    Payn, R. A.; Helton, A. M.; Poole, G.; Izurieta, C.; Bernhardt, E. S.; Burgin, A. J.

    2012-12-01

    Many hypotheses have been proposed to predict patterns of biogeochemical redox reactions based on the availability of electron donors and acceptors and the thermodynamic theory of chemistry. Our objective was to develop a computer model that would allow us to test various alternatives of these hypotheses against data gathered from soil slurry batch reactors, experimental soil perfusion cores, and in situ soil profile observations from the restored Timberlake Wetland in coastal North Carolina, USA. Software requirements to meet this objective included the ability to rapidly develop and compare different hypothetical formulations of kinetic and thermodynamic theory, and the ability to easily change the list of potential biogeochemical reactions used in the optimization scheme. For future work, we also required an object pattern that could easily be coupled with an existing soil hydrologic model. These requirements were met using Network Exchange Objects (NEO), our recently developed object-oriented distributed modeling framework that facilitates simulations of multiple interacting currencies moving through network-based systems. An initial implementation of the object pattern was developed in NEO based on maximizing growth of the microbial community from available dissolved organic carbon. We then used this implementation to build a modeling system for comparing results across multiple simulated batch reactors with varied initial solute concentrations, varied biogeochemical parameters, or varied optimization schemes. Among heterotrophic aerobic and anaerobic reactions, we have found that this model reasonably predicts the use of terminal electron acceptors in simulated batch reactors, where reactions with higher energy yields occur before reactions with lower energy yields. However, among the aerobic reactions, we have also found this model predicts dominance of chemoautotrophs (e.g., nitrifiers) when their electron donor (e.g., ammonium) is abundant, despite the

  18. Computationally efficient characterization of potential energy surfaces based on fingerprint distances

    NASA Astrophysics Data System (ADS)

    Schaefer, Bastian; Goedecker, Stefan

    2016-07-01

    An analysis of the network defined by the potential energy minima of multi-atomic systems and their connectivity via reaction pathways that go through transition states allows us to understand important characteristics like thermodynamic, dynamic, and structural properties. Unfortunately computing the transition states and reaction pathways in addition to the significant energetically low-lying local minima is a computationally demanding task. We here introduce a computationally efficient method that is based on a combination of the minima hopping global optimization method and the insight that uphill barriers tend to increase with increasing structural distances of the educt and product states. This method allows us to replace the exact connectivity information and transition state energies with alternative and approximate concepts. Without adding any significant additional cost to the minima hopping global optimization approach, this method allows us to generate an approximate network of the minima, their connectivity, and a rough measure for the energy needed for their interconversion. This can be used to obtain a first qualitative idea on important physical and chemical properties by means of a disconnectivity graph analysis. Besides the physical insight obtained by such an analysis, the gained knowledge can be used to make a decision if it is worthwhile or not to invest computational resources for an exact computation of the transition states and the reaction pathways. Furthermore it is demonstrated that the here presented method can be used for finding physically reasonable interconversion pathways that are promising input pathways for methods like transition path sampling or discrete path sampling.

  19. Computer Series 41: Potential-Energy Surfaces and Transition-State Theory.

    ERIC Educational Resources Information Center

    Moss, S. J.; Coady, C. J.

    1983-01-01

    Describes computer programs involving the London-Eyring-Polany-Sato method (LEPS). The programs provide a valuable means of introducing students to potential energy surfaces and to the foundations of transition state theory. Program listings (with copies of student scripts) or programs on DOS 3.3 disc are available from authors. (JN)

  20. The use of symbolic computation in radiative, energy, and neutron transport calculations. Final report

    SciTech Connect

    Frankel, J.I.

    1997-09-01

    This investigation used sysmbolic manipulation in developing analytical methods and general computational strategies for solving both linear and nonlinear, regular and singular integral and integro-differential equations which appear in radiative and mixed-mode energy transport. Contained in this report are seven papers which present the technical results as individual modules.

  1. Federal High Performance Computing and Communications Program. The Department of Energy Component.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Office of Energy Research.

    This report, profusely illustrated with color photographs and other graphics, elaborates on the Department of Energy (DOE) research program in High Performance Computing and Communications (HPCC). The DOE is one of seven agency programs within the Federal Research and Development Program working on HPCC. The DOE HPCC program emphasizes research in…

  2. A simplified approach to strain energy release rate computations for interlaminar fracture of composites

    NASA Technical Reports Server (NTRS)

    Armanios, Erian A.; Rehfield, Lawrence W.

    1989-01-01

    A simple approach for the strain energy release rate computations based on the finite element method and a singular fitting model is presented. The model uses the stress and displacement distributions at the delamination front. The method is applied to a mixed-mode double cracked-lap-shear composite configuration. The strain energy release rate components predicted by the model are compared with the finite element crack-closure method. The effect of the mesh size on the stress and displacement distribution is isolated. The strain energy release rates predicted by relatively coarse mesh sizes are in good agreement with the finite element crack closure method.

  3. Computer-Controlled System for Plasma Ion Energy Auto-Analyzer

    NASA Astrophysics Data System (ADS)

    Wu, Xian-qiu; Chen, Jun-fang; Jiang, Zhen-mei; Zhong, Qing-hua; Xiong, Yu-ying; Wu, Kai-hua

    2003-02-01

    A computer-controlled system for plasma ion energy auto-analyzer was technically studied for rapid and online measurement of plasma ion energy distribution. The system intelligently controls all the equipments via a RS-232 port, a printer port and a home-built circuit. The software designed by Lab VIEW G language automatically fulfils all of the tasks such as system initializing, adjustment of scanning-voltage, measurement of weak-current, data processing, graphic export, etc. By using the system, a few minutes are taken to acquire the whole ion energy distribution, which rapidly provides important parameters of plasma process techniques based on semiconductor devices and microelectronics.

  4. Evaluation of Emerging Energy-Efficient Heterogeneous Computing Platforms for Biomolecular and Cellular Simulation Workloads

    PubMed Central

    Stone, John E.; Hallock, Michael J.; Phillips, James C.; Peterson, Joseph R.; Luthey-Schulten, Zaida; Schulten, Klaus

    2016-01-01

    Many of the continuing scientific advances achieved through computational biology are predicated on the availability of ongoing increases in computational power required for detailed simulation and analysis of cellular processes on biologically-relevant timescales. A critical challenge facing the development of future exascale supercomputer systems is the development of new computing hardware and associated scientific applications that dramatically improve upon the energy efficiency of existing solutions, while providing increased simulation, analysis, and visualization performance. Mobile computing platforms have recently become powerful enough to support interactive molecular visualization tasks that were previously only possible on laptops and workstations, creating future opportunities for their convenient use for meetings, remote collaboration, and as head mounted displays for immersive stereoscopic viewing. We describe early experiences adapting several biomolecular simulation and analysis applications for emerging heterogeneous computing platforms that combine power-efficient system-on-chip multi-core CPUs with high-performance massively parallel GPUs. We present low-cost power monitoring instrumentation that provides sufficient temporal resolution to evaluate the power consumption of individual CPU algorithms and GPU kernels. We compare the performance and energy efficiency of scientific applications running on emerging platforms with results obtained on traditional platforms, identify hardware and algorithmic performance bottlenecks that affect the usability of these platforms, and describe avenues for improving both the hardware and applications in pursuit of the needs of molecular modeling tasks on mobile devices and future exascale computers. PMID:27516922

  5. PREFACE: International Conference on Computing in High Energy and Nuclear Physics (CHEP'07)

    NASA Astrophysics Data System (ADS)

    Sobie, Randall; Tafirout, Reda; Thomson, Jana

    2007-07-01

    The 2007 International Conference on Computing in High Energy and Nuclear Physics (CHEP) was held on 2-7 September 2007 in Victoria, British Columbia, Canada. CHEP is a major series of international conferences for physicists and computing professionals from the High Energy and Nuclear Physics community, Computer Science and Information Technology. The CHEP conference provides an international forum to exchange information on computing experience and needs for the community, and to review recent, ongoing, and future activities. The CHEP'07 conference had close to 500 attendees with a program that included plenary sessions of invited oral presentations, a number of parallel sessions comprising oral and poster presentations, and an industrial exhibition. Conference tracks covered topics in Online Computing, Event Processing, Software Components, Tools and Databases, Software Tools and Information Systems, Computing Facilities, Production Grids and Networking, Grid Middleware and Tools, Distributed Data Analysis and Information Management and Collaborative Tools. The conference included a successful whale-watching excursion involving over 200 participants and a banquet at the Royal British Columbia Museum. The next CHEP conference will be held in Prague in March 2009. We would like thank the sponsors of the conference and the staff at the TRIUMF Laboratory and the University of Victoria who made the CHEP'07 a success. Randall Sobie and Reda Tafirout CHEP'07 Conference Chairs

  6. Evaluation of Emerging Energy-Efficient Heterogeneous Computing Platforms for Biomolecular and Cellular Simulation Workloads.

    PubMed

    Stone, John E; Hallock, Michael J; Phillips, James C; Peterson, Joseph R; Luthey-Schulten, Zaida; Schulten, Klaus

    2016-05-01

    Many of the continuing scientific advances achieved through computational biology are predicated on the availability of ongoing increases in computational power required for detailed simulation and analysis of cellular processes on biologically-relevant timescales. A critical challenge facing the development of future exascale supercomputer systems is the development of new computing hardware and associated scientific applications that dramatically improve upon the energy efficiency of existing solutions, while providing increased simulation, analysis, and visualization performance. Mobile computing platforms have recently become powerful enough to support interactive molecular visualization tasks that were previously only possible on laptops and workstations, creating future opportunities for their convenient use for meetings, remote collaboration, and as head mounted displays for immersive stereoscopic viewing. We describe early experiences adapting several biomolecular simulation and analysis applications for emerging heterogeneous computing platforms that combine power-efficient system-on-chip multi-core CPUs with high-performance massively parallel GPUs. We present low-cost power monitoring instrumentation that provides sufficient temporal resolution to evaluate the power consumption of individual CPU algorithms and GPU kernels. We compare the performance and energy efficiency of scientific applications running on emerging platforms with results obtained on traditional platforms, identify hardware and algorithmic performance bottlenecks that affect the usability of these platforms, and describe avenues for improving both the hardware and applications in pursuit of the needs of molecular modeling tasks on mobile devices and future exascale computers.

  7. Application of an object-oriented programming paradigm in three-dimensional computer modeling of mechanically active gastrointestinal tissues.

    PubMed

    Rashev, P Z; Mintchev, M P; Bowes, K L

    2000-09-01

    The aim of this study was to develop a novel three-dimensional (3-D) object-oriented modeling approach incorporating knowledge of the anatomy, electrophysiology, and mechanics of externally stimulated excitable gastrointestinal (GI) tissues and emphasizing the "stimulus-response" principle of extracting the modeling parameters. The modeling method used clusters of class hierarchies representing GI tissues from three perspectives: 1) anatomical; 2) electrophysiological; and 3) mechanical. We elaborated on the first four phases of the object-oriented system development life-cycle: 1) analysis; 2) design; 3) implementation; and 4) testing. Generalized cylinders were used for the implementation of 3-D tissue objects modeling the cecum, the descending colon, and the colonic circular smooth muscle tissue. The model was tested using external neural electrical tissue excitation of the descending colon with virtual implanted electrodes and the stimulating current density distributions over the modeled surfaces were calculated. Finally, the tissue deformations invoked by electrical stimulation were estimated and represented by a mesh-surface visualization technique.

  8. Outer Membrane Protein Folding and Topology from a Computational Transfer Free Energy Scale.

    PubMed

    Lin, Meishan; Gessmann, Dennis; Naveed, Hammad; Liang, Jie

    2016-03-02

    Knowledge of the transfer free energy of amino acids from aqueous solution to a lipid bilayer is essential for understanding membrane protein folding and for predicting membrane protein structure. Here we report a computational approach that can calculate the folding free energy of the transmembrane region of outer membrane β-barrel proteins (OMPs) by combining an empirical energy function with a reduced discrete state space model. We quantitatively analyzed the transfer free energies of 20 amino acid residues at the center of the lipid bilayer of OmpLA. Our results are in excellent agreement with the experimentally derived hydrophobicity scales. We further exhaustively calculated the transfer free energies of 20 amino acids at all positions in the TM region of OmpLA. We found that the asymmetry of the Gram-negative bacterial outer membrane as well as the TM residues of an OMP determine its functional fold in vivo. Our results suggest that the folding process of an OMP is driven by the lipid-facing residues in its hydrophobic core, and its NC-IN topology is determined by the differential stabilities of OMPs in the asymmetrical outer membrane. The folding free energy is further reduced by lipid A and assisted by general depth-dependent cooperativities that exist between polar and ionizable residues. Moreover, context-dependency of transfer free energies at specific positions in OmpLA predict regions important for protein function as well as structural anomalies. Our computational approach is fast, efficient and applicable to any OMP.

  9. Methods for Efficiently and Accurately Computing Quantum Mechanical Free Energies for Enzyme Catalysis.

    PubMed

    Kearns, F L; Hudson, P S; Boresch, S; Woodcock, H L

    2016-01-01

    Enzyme activity is inherently linked to free energies of transition states, ligand binding, protonation/deprotonation, etc.; these free energies, and thus enzyme function, can be affected by residue mutations, allosterically induced conformational changes, and much more. Therefore, being able to predict free energies associated with enzymatic processes is critical to understanding and predicting their function. Free energy simulation (FES) has historically been a computational challenge as it requires both the accurate description of inter- and intramolecular interactions and adequate sampling of all relevant conformational degrees of freedom. The hybrid quantum mechanical molecular mechanical (QM/MM) framework is the current tool of choice when accurate computations of macromolecular systems are essential. Unfortunately, robust and efficient approaches that employ the high levels of computational theory needed to accurately describe many reactive processes (ie, ab initio, DFT), while also including explicit solvation effects and accounting for extensive conformational sampling are essentially nonexistent. In this chapter, we will give a brief overview of two recently developed methods that mitigate several major challenges associated with QM/MM FES: the QM non-Boltzmann Bennett's acceptance ratio method and the QM nonequilibrium work method. We will also describe usage of these methods to calculate free energies associated with (1) relative properties and (2) along reaction paths, using simple test cases with relevance to enzymes examples.

  10. Computation of free energy differences through nonequilibrium stochastic dynamics: The reaction coordinate case

    SciTech Connect

    Lelievre, Tony . E-mail: lelievre@cermics.enpc.fr; Rousset, Mathias . E-mail: rousset@cermics.enpc.fr; Stoltz, Gabriel . E-mail: stoltz@cermics.enpc.fr

    2007-03-20

    The computation of free energy differences through an exponential weighting of out-of-equilibrium paths (known as the Jarzynski equality [C. Jarzynski, Equilibrium free energy differences from nonequilibrium measurements: a master equation approach, Phys. Rev. E 56 (5) (1997) 5018-5035, C. Jarzynski, Nonequilibrium equality for free energy differences, Phys. Rev. Lett. 78 (14) (1997) 2690-2693]) is often used for transitions between states described by an external parameter in the Hamiltonian. An extension to transitions between states defined by different values of some reaction coordinate is presented here, using a projected Brownian dynamics. In contrast with other approaches (see e.g. [S. Park, F. Khalili-Araghi, E. Tajkhorshid, K. Schulten, Free energy calculation from steered molecular dynamics simulations using Jarzynski's equality, J. Chem. Phys. 119 (6) (2003) 3559-3566]), a projection is used rather than a constraining potential to let the constraints associated with the reaction coordinate evolve. It is shown how to use the Lagrange multipliers associated with these constraints to compute the work associated with a given trajectory. Appropriate discretizations are proposed. Some numerical results demonstrate the applicability of the method for the computation of free energy difference profiles.

  11. Dynamic Voltage Frequency Scaling Simulator for Real Workflows Energy-Aware Management in Green Cloud Computing

    PubMed Central

    Cotes-Ruiz, Iván Tomás; Prado, Rocío P.; García-Galán, Sebastián; Muñoz-Expósito, José Enrique; Ruiz-Reyes, Nicolás

    2017-01-01

    Nowadays, the growing computational capabilities of Cloud systems rely on the reduction of the consumed power of their data centers to make them sustainable and economically profitable. The efficient management of computing resources is at the heart of any energy-aware data center and of special relevance is the adaptation of its performance to workload. Intensive computing applications in diverse areas of science generate complex workload called workflows, whose successful management in terms of energy saving is still at its beginning. WorkflowSim is currently one of the most advanced simulators for research on workflows processing, offering advanced features such as task clustering and failure policies. In this work, an expected power-aware extension of WorkflowSim is presented. This new tool integrates a power model based on a computing-plus-communication design to allow the optimization of new management strategies in energy saving considering computing, reconfiguration and networks costs as well as quality of service, and it incorporates the preeminent strategy for on host energy saving: Dynamic Voltage Frequency Scaling (DVFS). The simulator is designed to be consistent in different real scenarios and to include a wide repertory of DVFS governors. Results showing the validity of the simulator in terms of resources utilization, frequency and voltage scaling, power, energy and time saving are presented. Also, results achieved by the intra-host DVFS strategy with different governors are compared to those of the data center using a recent and successful DVFS-based inter-host scheduling strategy as overlapped mechanism to the DVFS intra-host technique. PMID:28085932

  12. Dynamic Voltage Frequency Scaling Simulator for Real Workflows Energy-Aware Management in Green Cloud Computing.

    PubMed

    Cotes-Ruiz, Iván Tomás; Prado, Rocío P; García-Galán, Sebastián; Muñoz-Expósito, José Enrique; Ruiz-Reyes, Nicolás

    2017-01-01

    Nowadays, the growing computational capabilities of Cloud systems rely on the reduction of the consumed power of their data centers to make them sustainable and economically profitable. The efficient management of computing resources is at the heart of any energy-aware data center and of special relevance is the adaptation of its performance to workload. Intensive computing applications in diverse areas of science generate complex workload called workflows, whose successful management in terms of energy saving is still at its beginning. WorkflowSim is currently one of the most advanced simulators for research on workflows processing, offering advanced features such as task clustering and failure policies. In this work, an expected power-aware extension of WorkflowSim is presented. This new tool integrates a power model based on a computing-plus-communication design to allow the optimization of new management strategies in energy saving considering computing, reconfiguration and networks costs as well as quality of service, and it incorporates the preeminent strategy for on host energy saving: Dynamic Voltage Frequency Scaling (DVFS). The simulator is designed to be consistent in different real scenarios and to include a wide repertory of DVFS governors. Results showing the validity of the simulator in terms of resources utilization, frequency and voltage scaling, power, energy and time saving are presented. Also, results achieved by the intra-host DVFS strategy with different governors are compared to those of the data center using a recent and successful DVFS-based inter-host scheduling strategy as overlapped mechanism to the DVFS intra-host technique.

  13. Simple prescription for computing the interparticle potential energy for D-dimensional gravity systems

    NASA Astrophysics Data System (ADS)

    Accioly, Antonio; Helayël-Neto, José; Barone, F. E.; Herdy, Wallace

    2015-02-01

    A straightforward prescription for computing the D-dimensional potential energy of gravitational models, which is strongly based on the Feynman path integral, is built up. Using this method, the static potential energy for the interaction of two masses is found in the context of D-dimensional higher-derivative gravity models, and its behavior is analyzed afterwards in both ultraviolet and infrared regimes. As a consequence, two new gravity systems in which the potential energy is finite at the origin, respectively, in D = 5 and D = 6, are found. Since the aforementioned prescription is equivalent to that based on the marriage between quantum mechanics (to leading order, i.e., in the first Born approximation) and the nonrelativistic limit of quantum field theory, and bearing in mind that the latter relies basically on the calculation of the nonrelativistic Feynman amplitude ({{M}NR}), a trivial expression for computing {{M}NR} is obtained from our prescription as an added bonus.

  14. Computing converged free energy differences between levels of theory via nonequilibrium work methods: Challenges and opportunities.

    PubMed

    Kearns, Fiona L; Hudson, Phillip S; Woodcock, Henry L; Boresch, Stefan

    2017-03-08

    We demonstrate that Jarzynski's equation can be used to reliably compute free energy differences between low and high level representations of systems. The need for such a calculation arises when employing the so-called "indirect" approach to free energy simulations with mixed quantum mechanical/molecular mechanical (QM/MM) Hamiltonians; a popular technique for circumventing extensive simulations involving quantum chemical computations. We have applied this methodology to several small and medium sized organic molecules, both in the gas phase and explicit solvent. Test cases include several systems for which the standard approach; that is, free energy perturbation between low and high level description, fails to converge. Finally, we identify three major areas in which the difference between low and high level representations make the calculation of ΔAlow→high difficult: bond stretching and angle bending, different preferred conformations, and the response of the MM region to the charge distribution of the QM region. © 2016 Wiley Periodicals, Inc.

  15. Analytic computation of energy derivatives - Relationships among partial derivatives of a variationally determined function

    NASA Technical Reports Server (NTRS)

    King, H. F.; Komornicki, A.

    1986-01-01

    Formulas are presented relating Taylor series expansion coefficients of three functions of several variables, the energy of the trial wave function (W), the energy computed using the optimized variational wave function (E), and the response function (lambda), under certain conditions. Partial derivatives of lambda are obtained through solution of a recursive system of linear equations, and solution through order n yields derivatives of E through order 2n + 1, extending Puley's application of Wigner's 2n + 1 rule to partial derivatives in couple perturbation theory. An examination of numerical accuracy shows that the usual two-term second derivative formula is less stable than an alternative four-term formula, and that previous claims that energy derivatives are stationary properties of the wave function are fallacious. The results have application to quantum theoretical methods for the computation of derivative properties such as infrared frequencies and intensities.

  16. The Nuclear Energy Advanced Modeling and Simulation Enabling Computational Technologies FY09 Report

    SciTech Connect

    Diachin, L F; Garaizar, F X; Henson, V E; Pope, G

    2009-10-12

    In this document we report on the status of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Enabling Computational Technologies (ECT) effort. In particular, we provide the context for ECT In the broader NEAMS program and describe the three pillars of the ECT effort, namely, (1) tools and libraries, (2) software quality assurance, and (3) computational facility (computers, storage, etc) needs. We report on our FY09 deliverables to determine the needs of the integrated performance and safety codes (IPSCs) in these three areas and lay out the general plan for software quality assurance to meet the requirements of DOE and the DOE Advanced Fuel Cycle Initiative (AFCI). We conclude with a brief description of our interactions with the Idaho National Laboratory computer center to determine what is needed to expand their role as a NEAMS user facility.

  17. Applied & Computational MathematicsChallenges for the Design and Control of Dynamic Energy Systems

    SciTech Connect

    Brown, D L; Burns, J A; Collis, S; Grosh, J; Jacobson, C A; Johansen, H; Mezic, I; Narayanan, S; Wetter, M

    2011-03-10

    The Energy Independence and Security Act of 2007 (EISA) was passed with the goal 'to move the United States toward greater energy independence and security.' Energy security and independence cannot be achieved unless the United States addresses the issue of energy consumption in the building sector and significantly reduces energy consumption in buildings. Commercial and residential buildings account for approximately 40% of the U.S. energy consumption and emit 50% of CO{sub 2} emissions in the U.S. which is more than twice the total energy consumption of the entire U.S. automobile and light truck fleet. A 50%-80% improvement in building energy efficiency in both new construction and in retrofitting existing buildings could significantly reduce U.S. energy consumption and mitigate climate change. Reaching these aggressive building efficiency goals will not happen without significant Federal investments in areas of computational and mathematical sciences. Applied and computational mathematics are required to enable the development of algorithms and tools to design, control and optimize energy efficient buildings. The challenge has been issued by the U.S. Secretary of Energy, Dr. Steven Chu (emphasis added): 'We need to do more transformational research at DOE including computer design tools for commercial and residential buildings that enable reductions in energy consumption of up to 80 percent with investments that will pay for themselves in less than 10 years.' On July 8-9, 2010 a team of technical experts from industry, government and academia were assembled in Arlington, Virginia to identify the challenges associated with developing and deploying newcomputational methodologies and tools thatwill address building energy efficiency. These experts concluded that investments in fundamental applied and computational mathematics will be required to build enabling technology that can be used to realize the target of 80% reductions in energy consumption. In addition the

  18. Vertically oriented arrays of ReS2 nanosheets for electrochemical energy storage and electrocatalysis

    SciTech Connect

    Gao, Jian; Li, Lu; Tan, Jiawei; Sun, Hao; Li, Baichang; Idrobo, Juan Carlos; Singh, Chandra Veer; Lu, Toh -Ming; Koratkar, Nikhil

    2016-05-17

    Here, transition-metal dichalcogenide (TMD) nanolayers show potential as high-performance catalysts in energy conversion and storage devices. Synthetic TMDs produced by chemical-vapor deposition (CVD) methods tend to grow parallel to the growth substrate. Here, we show that with the right precursors and appropriate tuning of the CVD growth conditions, ReS2 nanosheets can be made to orient perpendicular to the growth substrate. This accomplishes two important objectives; first, it drastically increases the wetted or exposed surface area of the ReS2 sheets, and second, it exposes the sharp edges and corners of the ReS2 sheets. We show that these structural features of the vertically grown ReS2 sheets can be exploited to significantly improve their performance as polysulfide immobilizers and electrochemical catalysts in lithium–sulfur (Li–S) batteries and in hydrogen evolution reactions (HER). After 300 cycles, the specific capacity of the Li–S battery with vertical ReS2 catalyst is retained above 750 mA h g–1, with only ~0.063% capacity decay per cycle, much better than the baseline battery (without ReS2), which shows ~0.184% capacity decay per cycle under the same test conditions. As a HER catalyst, the vertical ReS2 provides very small onset overpotential (<100 mV) and an exceptional exchange-current density (~67.6 μA/cm2), which is vastly superior to the baseline electrode without ReS2.

  19. A site oriented supercomputer for theoretical physics: The Fermilab Advanced Computer Program Multi Array Processor System (ACMAPS)

    SciTech Connect

    Nash, T.; Atac, R.; Cook, A.; Deppe, J.; Fischler, M.; Gaines, I.; Husby, D.; Pham, T.; Zmuda, T.; Eichten, E.

    1989-03-06

    The ACPMAPS multipocessor is a highly cost effective, local memory parallel computer with a hypercube or compound hypercube architecture. Communication requires the attention of only the two communicating nodes. The design is aimed at floating point intensive, grid like problems, particularly those with extreme computing requirements. The processing nodes of the system are single board array processors, each with a peak power of 20 Mflops, supported by 8 Mbytes of data and 2 Mbytes of instruction memory. The system currently being assembled has a peak power of 5 Gflops. The nodes are based on the Weitek XL Chip set. The system delivers performance at approximately $300/Mflop. 8 refs., 4 figs.

  20. Computations of Lifshitz-van der Waals interaction energies between irregular particles and surfaces at all separations for resuspension modelling

    NASA Astrophysics Data System (ADS)

    Priye, Aashish; Marlow, William H.

    2013-10-01

    The phenomenon of particle resuspension plays a vital role in numerous fields. Among many aspects of particle resuspension dynamics, a dominant concern is the accurate description and formulation of the van der Waals (vdW) interactions between the particle and substrate. Current models treat adhesion by incorporating a material-dependent Hamaker's constant which relies on the heuristic Hamaker's two-body interactions. However, this assumption of pairwise summation of interaction energies can lead to significant errors in condensed matter as it does not take into account the many-body interaction and retardation effects. To address these issues, an approach based on Lifshitz continuum theory of vdW interactions has been developed to calculate the principal many-body interactions between arbitrary geometries at all separation distances to a high degree of accuracy through Lifshitz's theory. We have applied this numerical implementation to calculate the many-body vdW interactions between spherical particles and surfaces with sinusoidally varying roughness profile and also to non-spherical particles (cubes, cylinders, tetrahedron etc) orientated differently with respect to the surface. Our calculations revealed that increasing the surface roughness amplitude decreases the adhesion force and non-spherical particles adhere to the surfaces more strongly when their flatter sides are oriented towards the surface. Such practical shapes and structures of particle-surface systems have not been previously considered in resuspension models and this rigorous treatment of vdW interactions provides more realistic adhesion forces between the particle and the surface which can then be coupled with computational fluid dynamics models to improve the predictive capabilities of particle resuspension dynamics.

  1. Computer usage and national energy consumption: Results from a field-metering study

    SciTech Connect

    Desroches, Louis-Benoit; Fuchs, Heidi; Greenblatt, Jeffery; Pratt, Stacy; Willem, Henry; Claybaugh, Erin; Beraki, Bereket; Nagaraju, Mythri; Price, Sarah; Young, Scott

    2014-12-01

    The electricity consumption of miscellaneous electronic loads (MELs) in the home has grown in recent years, and is expected to continue rising. Consumer electronics, in particular, are characterized by swift technological innovation, with varying impacts on energy use. Desktop and laptop computers make up a significant share of MELs electricity consumption, but their national energy use is difficult to estimate, given uncertainties around shifting user behavior. This report analyzes usage data from 64 computers (45 desktop, 11 laptop, and 8 unknown) collected in 2012 as part of a larger field monitoring effort of 880 households in the San Francisco Bay Area, and compares our results to recent values from the literature. We find that desktop computers are used for an average of 7.3 hours per day (median = 4.2 h/d), while laptops are used for a mean 4.8 hours per day (median = 2.1 h/d). The results for laptops are likely underestimated since they can be charged in other, unmetered outlets. Average unit annual energy consumption (AEC) for desktops is estimated to be 194 kWh/yr (median = 125 kWh/yr), and for laptops 75 kWh/yr (median = 31 kWh/yr). We estimate national annual energy consumption for desktop computers to be 20 TWh. National annual energy use for laptops is estimated to be 11 TWh, markedly higher than previous estimates, likely reflective of laptops drawing more power in On mode in addition to greater market penetration. This result for laptops, however, carries relatively higher uncertainty compared to desktops. Different study methodologies and definitions, changing usage patterns, and uncertainty about how consumers use computers must be considered when interpreting our results with respect to existing analyses. Finally, as energy consumption in On mode is predominant, we outline several energy savings opportunities: improved power management (defaulting to low-power modes after periods of inactivity as well as power scaling), matching the rated power

  2. Computer Simulation of Reflection High Energy Electron Diffraction and Low Energy Electron Diffraction

    NASA Astrophysics Data System (ADS)

    Flexner, Soren; Davidson, Bruce; Odonnell, James; Eckstein, J. N.

    2000-03-01

    Simulation software for Reflection High Energy Electron Diffraction (RHEED) and Low Energy Electron Diffraction (LEED) imaging has been developed using the C programming language. This software models experimental electron diffraction patterns obtained in-situ during deposition of oxide films by molecular beam epitaxy in our lab. Using the kinematical approximation the software considers the phase contributions from scatterers via a modifiable, finite, two or three-dimensional real lattice to construct the RHEED and LEED images. We have found quantitative agreement in the positions of diffraction maxima, and proceed to use the software to explore the qualitative aspects of La and Mn termination in LaMnO2, surface Jahn-Teller distortion in perovskites, terracing in various materials, and domain formation in a-axis DBCO resulting from in-plane rotation of the c-axis. In addition the software is used to examine proposed surface reconstructions capable of producing, e.g. the elevated half-order streaks seen along the [100] azimuth during growth of LaMnO2.

  3. When Western Technology Meets Oriental Culture: Use of Computer-Mediated Communication in a Higher Education Classroom.

    ERIC Educational Resources Information Center

    Tyan, Nay-ching Nancy; Hong, Frank Min-chow

    A computer-mediated communication (CMC) device, Virtual Classroom & Virtual Corporation System (VICTORY) was developed and integrated into a Taiwan higher education classroom with the aim of providing a constructive learning environment where high-quality instructional interactions and true collaboration existed among learners. Individual…

  4. Task-oriented training with computer gaming in people with rheumatoid arthritisor osteoarthritis of the hand: study protocol of a randomized controlled pilot trial

    PubMed Central

    2013-01-01

    Background Significant restriction in the ability to participate in home, work and community life results from pain, fatigue, joint damage, stiffness and reduced joint range of motion and muscle strength in people with rheumatoid arthritis or osteoarthritis of the hand. With modest evidence on the therapeutic effectiveness of conventional hand exercises, a task-oriented training program via real life object manipulations has been developed for people with arthritis. An innovative, computer-based gaming platform that allows a broad range of common objects to be seamlessly transformed into therapeutic input devices through instrumentation with a motion-sense mouse has also been designed. Personalized objects are selected to target specific training goals such as graded finger mobility, strength, endurance or fine/gross dexterous functions. The movements and object manipulation tasks that replicate common situations in everyday living will then be used to control and play any computer game, making practice challenging and engaging. Methods/Design The ongoing study is a 6-week, single-center, parallel-group, equally allocated and assessor-blinded pilot randomized controlled trial. Thirty people with rheumatoid arthritis or osteoarthritis affecting the hand will be randomized to receive either conventional hand exercises or the task-oriented training. The purpose is to determine a preliminary estimation of therapeutic effectiveness and feasibility of the task-oriented training program. Performance based and self-reported hand function, and exercise compliance are the study outcomes. Changes in outcomes (pre to post intervention) within each group will be assessed by paired Student t test or Wilcoxon signed-rank test and between groups (control versus experimental) post intervention using unpaired Student t test or Mann–Whitney U test. Discussion The study findings will inform decisions on the feasibility, safety and completion rate and will also provide preliminary

  5. Energy Scaling Advantages of Resistive Memory Crossbar Based Computation and Its Application to Sparse Coding

    PubMed Central

    Agarwal, Sapan; Quach, Tu-Thach; Parekh, Ojas; Hsia, Alexander H.; DeBenedictis, Erik P.; James, Conrad D.; Marinella, Matthew J.; Aimone, James B.

    2016-01-01

    The exponential increase in data over the last decade presents a significant challenge to analytics efforts that seek to process and interpret such data for various applications. Neural-inspired computing approaches are being developed in order to leverage the computational properties of the analog, low-power data processing observed in biological systems. Analog resistive memory crossbars can perform a parallel read or a vector-matrix multiplication as well as a parallel write or a rank-1 update with high computational efficiency. For an N × N crossbar, these two kernels can be O(N) more energy efficient than a conventional digital memory-based architecture. If the read operation is noise limited, the energy to read a column can be independent of the crossbar size (O(1)). These two kernels form the basis of many neuromorphic algorithms such as image, text, and speech recognition. For instance, these kernels can be applied to a neural sparse coding algorithm to give an O(N) reduction in energy for the entire algorithm when run with finite precision. Sparse coding is a rich problem with a host of applications including computer vision, object tracking, and more generally unsupervised learning. PMID:26778946

  6. Formal Estimation of Errors in Computed Absolute Interaction Energies of Protein-ligand Complexes

    PubMed Central

    Faver, John C.; Benson, Mark L.; He, Xiao; Roberts, Benjamin P.; Wang, Bing; Marshall, Michael S.; Kennedy, Matthew R.; Sherrill, C. David; Merz, Kenneth M.

    2011-01-01

    A largely unsolved problem in computational biochemistry is the accurate prediction of binding affinities of small ligands to protein receptors. We present a detailed analysis of the systematic and random errors present in computational methods through the use of error probability density functions, specifically for computed interaction energies between chemical fragments comprising a protein-ligand complex. An HIV-II protease crystal structure with a bound ligand (indinavir) was chosen as a model protein-ligand complex. The complex was decomposed into twenty-one (21) interacting fragment pairs, which were studied using a number of computational methods. The chemically accurate complete basis set coupled cluster theory (CCSD(T)/CBS) interaction energies were used as reference values to generate our error estimates. In our analysis we observed significant systematic and random errors in most methods, which was surprising especially for parameterized classical and semiempirical quantum mechanical calculations. After propagating these fragment-based error estimates over the entire protein-ligand complex, our total error estimates for many methods are large compared to the experimentally determined free energy of binding. Thus, we conclude that statistical error analysis is a necessary addition to any scoring function attempting to produce reliable binding affinity predictions. PMID:21666841

  7. Energy scaling advantages of resistive memory crossbar based computation and its application to sparse coding

    DOE PAGES

    Agarwal, Sapan; Quach, Tu -Thach; Parekh, Ojas; ...

    2016-01-06

    In this study, the exponential increase in data over the last decade presents a significant challenge to analytics efforts that seek to process and interpret such data for various applications. Neural-inspired computing approaches are being developed in order to leverage the computational properties of the analog, low-power data processing observed in biological systems. Analog resistive memory crossbars can perform a parallel read or a vector-matrix multiplication as well as a parallel write or a rank-1 update with high computational efficiency. For an N × N crossbar, these two kernels can be O(N) more energy efficient than a conventional digital memory-basedmore » architecture. If the read operation is noise limited, the energy to read a column can be independent of the crossbar size (O(1)). These two kernels form the basis of many neuromorphic algorithms such as image, text, and speech recognition. For instance, these kernels can be applied to a neural sparse coding algorithm to give an O(N) reduction in energy for the entire algorithm when run with finite precision. Sparse coding is a rich problem with a host of applications including computer vision, object tracking, and more generally unsupervised learning.« less

  8. Energy scaling advantages of resistive memory crossbar based computation and its application to sparse coding

    SciTech Connect

    Agarwal, Sapan; Quach, Tu -Thach; Parekh, Ojas; DeBenedictis, Erik P.; James, Conrad D.; Marinella, Matthew J.; Aimone, James B.

    2016-01-06

    In this study, the exponential increase in data over the last decade presents a significant challenge to analytics efforts that seek to process and interpret such data for various applications. Neural-inspired computing approaches are being developed in order to leverage the computational properties of the analog, low-power data processing observed in biological systems. Analog resistive memory crossbars can perform a parallel read or a vector-matrix multiplication as well as a parallel write or a rank-1 update with high computational efficiency. For an N × N crossbar, these two kernels can be O(N) more energy efficient than a conventional digital memory-based architecture. If the read operation is noise limited, the energy to read a column can be independent of the crossbar size (O(1)). These two kernels form the basis of many neuromorphic algorithms such as image, text, and speech recognition. For instance, these kernels can be applied to a neural sparse coding algorithm to give an O(N) reduction in energy for the entire algorithm when run with finite precision. Sparse coding is a rich problem with a host of applications including computer vision, object tracking, and more generally unsupervised learning.

  9. Computed crystal energy landscapes for understanding and predicting organic crystal structures and polymorphism.

    PubMed

    Price, Sarah Sally L

    2009-01-20

    The phenomenon of polymorphism, the ability of a molecule to adopt more than one crystal structure, is a well-established property of crystalline solids. The possible variations in physical properties between polymorphs make the reliable reproduction of a crystalline form essential for all research using organic materials, as well as quality control in manufacture. Thus, the last two decades have seen both an increase in interest in polymorphism and the availability of the computer power needed to make the computational prediction of organic crystal structures a practical possibility. In the past decade, researchers have made considerable improvements in the theoretical basis for calculating the sets of structures that are within the energy range of possible polymorphism, called crystal energy landscapes. It is common to find that a molecule has a wide variety of ways of packing with lattice energy within a few kilojoules per mole of the most stable structure. However, as we develop methods to search for and characterize "all" solid forms, it is also now usual for polymorphs and solvates to be found. Thus, the computed crystal energy landscape reflects and to an increasing extent "predicts" the emerging complexity of the solid state observed for many organic molecules. This Account will discuss the ways in which the calculation of the crystal energy landscape of a molecule can be used as a complementary technique to solid form screening for polymorphs. Current methods can predict the known crystal structure, even under "blind test" conditions, but such successes are generally restricted to those structures that are the most stable over a wide range of thermodynamic conditions. The other low-energy structures can be alternative polymorphs, which have sometimes been found in later experimental studies. Examining the computed structures reveals the various compromises between close packing, hydrogen bonding, and pi-pi stacking that can result in energetically feasible

  10. Reducing Vehicle Weight and Improving U.S. Energy Efficiency Using Integrated Computational Materials Engineering

    NASA Astrophysics Data System (ADS)

    Joost, William J.

    2012-09-01

    Transportation accounts for approximately 28% of U.S. energy consumption with the majority of transportation energy derived from petroleum sources. Many technologies such as vehicle electrification, advanced combustion, and advanced fuels can reduce transportation energy consumption by improving the efficiency of cars and trucks. Lightweight materials are another important technology that can improve passenger vehicle fuel efficiency by 6-8% for each 10% reduction in weight while also making electric and alternative vehicles more competitive. Despite the opportunities for improved efficiency, widespread deployment of lightweight materials for automotive structures is hampered by technology gaps most often associated with performance, manufacturability, and cost. In this report, the impact of reduced vehicle weight on energy efficiency is discussed with a particular emphasis on quantitative relationships determined by several researchers. The most promising lightweight materials systems are described along with a brief review of the most significant technical barriers to their implementation. For each material system, the development of accurate material models is critical to support simulation-intensive processing and structural design for vehicles; improved models also contribute to an integrated computational materials engineering (ICME) approach for addressing technical barriers and accelerating deployment. The value of computational techniques is described by considering recent ICME and computational materials science success stories with an emphasis on applying problem-specific methods.

  11. TU-A-12A-08: Computing Longitudinal Material Changes in Bone Metastases Using Dual Energy Computed Tomography

    SciTech Connect

    Schmidtlein, CR; Hwang, S; Veeraraghavan, H; Fehr, D; Humm, J; Deasy, J

    2014-06-15

    Purpose: This study demonstrates a methodology for tracking changes in metastatic bone disease using trajectories in material basis space in serial dual energy computed tomography (DECT) studies. Methods: This study includes patients with bone metastases from breast cancer that had clinical surveillance CT scans using a General Electric CT750HD in dual energy mode. A radiologist defined regions-of-interested (ROI) for bone metastasis, normal bone, and marrow across the serial DECT scans. Our approach employs a Radon transform to forward-projection the basis images, namely, water and iodine, into sinogram space. This data is then repartitioned into fat/bone and effective density/Z image pairs using assumed energy spectrums for the x-ray energies. This approach both helps remove negative material densities and avoids adding spectrum-hardening artifacts. These new basis data sets were then reconstructed via filtered back-projection to create new material basis pair images. The trajectories of these pairs were then plotted in the new basis space providing a means to both visualize and quantitatively measure changes in the material properties of the tumors. Results: ROI containing radiologist defined metastatic bone disease showed well-defined trajectories in both fat/bone and effective density/Z space. ROI that contained radiologist defined normal bone and marrow did not exhibit any discernible trajectories and were stable from scan to scan. Conclusions: The preliminary results show that changes in material composition and effective density/Z image pairs were seen primarily in metastasis and not in normal tissue. This study indicates that by using routine clinical DECT it may be possible to monitor therapy response of bone metastases because healing or worsening bone metastases change material composition of bone. Additional studies are needed to further validate these results and to test for their correlation with outcome.

  12. A 4-cylinder Stirling engine computer program with dynamic energy equations

    NASA Technical Reports Server (NTRS)

    Daniele, C. J.; Lorenzo, C. F.

    1983-01-01

    A computer program for simulating the steady state and transient performance of a four cylinder Stirling engine is presented. The thermodynamic model includes both continuity and energy equations and linear momentum terms (flow resistance). Each working space between the pistons is broken into seven control volumes. Drive dynamics and vehicle load effects are included. The model contains 70 state variables. Also included in the model are piston rod seal leakage effects. The computer program includes a model of a hydrogen supply system, from which hydrogen may be added to the system to accelerate the engine. Flow charts are provided.

  13. Orientation-dependent energy level alignment and film growth of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on HOPG

    SciTech Connect

    Lyu, Lu; Niu, Dongmei Xie, Haipeng; Cao, Ningtong; Zhang, Hong; Zhang, Yuhe; Liu, Peng; Gao, Yongli

    2016-01-21

    Combining ultraviolet photoemission spectroscopy, X-ray photoemission spectroscopy, atomic force microscopy, and X-ray diffraction measurements, we performed a systematic investigation on the correlation of energy level alignment, film growth, and molecular orientation of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on highly oriented pyrolytic graphite. The molecules lie down in the first layer and then stand up from the second layer. The ionization potential shows a sharp decrease from the lying down region to the standing up region. When C8-BTBT molecules start standing up, unconventional energy level band-bending-like shifts are observed as the film thickness increases. These shifts are ascribed to gradual decreasing of the molecular tilt angle about the substrate normal with the increasing film thickness.

  14. SIVEH: Numerical Computing Simulation of Wireless Energy-Harvesting Sensor Nodes

    PubMed Central

    Sanchez, Antonio; Blanc, Sara; Climent, Salvador; Yuste, Pedro; Ors, Rafael

    2013-01-01

    The paper presents a numerical energy harvesting model for sensor nodes, SIVEH (Simulator I–V for EH), based on I–V hardware tracking. I–V tracking is demonstrated to be more accurate than traditional energy modeling techniques when some of the components present different power dissipation at either different operating voltages or drawn currents. SIVEH numerical computing allows fast simulation of long periods of time—days, weeks, months or years—using real solar radiation curves. Moreover, SIVEH modeling has been enhanced with sleep time rate dynamic adjustment, while seeking energy-neutral operation. This paper presents the model description, a functional verification and a critical comparison with the classic energy approach. PMID:24008287

  15. Absolute Binding Free Energy Calculations: On the Accuracy of Computational Scoring of Protein-ligand Interactions

    PubMed Central

    Singh, Nidhi; Warshel, Arieh

    2010-01-01

    Calculating the absolute binding free energies is a challenging task. Reliable estimates of binding free energies should provide a guide for rational drug design. It should also provide us with deeper understanding of the correlation between protein structure and its function. Further applications may include identifying novel molecular scaffolds and optimizing lead compounds in computer-aided drug design. Available options to evaluate the absolute binding free energies range from the rigorous but expensive free energy perturbation to the microscopic Linear Response Approximation (LRA/β version) and its variants including the Linear Interaction Energy (LIE) to the more approximated and considerably faster scaled Protein Dipoles Langevin Dipoles (PDLD/S-LRA version), as well as the less rigorous Molecular Mechanics Poisson–Boltzmann/Surface Area (MM/PBSA) and Generalized Born/Surface Area (MM/GBSA) to the less accurate scoring functions. There is a need for an assessment of the performance of different approaches in terms of computer time and reliability. We present a comparative study of the LRA/β, the LIE, the PDLD/S-LRA/β and the more widely used MM/PBSA and assess their abilities to estimate the absolute binding energies. The LRA and LIE methods perform reasonably well but require specialized parameterization for the non-electrostatic term. On the average, the PDLD/S-LRA/β performs effectively. Our assessment of the MM/PBSA is less optimistic. This approach appears to provide erroneous estimates of the absolute binding energies due to its incorrect entropies and the problematic treatment of electrostatic energies. Overall, the PDLD/S-LRA/β appears to offer an appealing option for the final stages of massive screening approaches. PMID:20186976

  16. Lennard-Jones systems near solid walls: computing interfacial free energies from molecular simulation methods.

    PubMed

    Benjamin, Ronald; Horbach, Jürgen

    2013-08-28

    Different computational techniques in combination with molecular dynamics computer simulation are used to determine the wall-liquid and the wall-crystal interfacial free energies of a modified Lennard-Jones (LJ) system in contact with a solid wall. Two different kinds of solid walls are considered: a flat structureless wall and a structured wall consisting of an ideal crystal with the particles rigidly attached to fcc lattice sites. Interfacial free energies are determined by a thermodynamic integration scheme, the anisotropy of the pressure tensor, the non-equilibrium work method based on Bennett acceptance criteria, and a method using Cahn's adsorption equations based on the interfacial thermodynamics of Gibbs. For the flat wall, interfacial free energies as a function of different densities of the LJ liquid and as a function of temperature along the coexistence curve are calculated. In the case of a structured wall, the interaction strength between the wall and the LJ system and the lattice constant of the structured wall are varied. Using the values of the wall-liquid and wall-crystal interfacial energies along with the value for the crystal-liquid interfacial free energy determined previously for the same system by the "cleaving potential method," we obtain the contact angle as a function of various parameters; in particular, the conditions are found under which partial wetting occurs.

  17. Computing the Free Energy along a Reaction Coordinate Using Rigid Body Dynamics.

    PubMed

    Tao, Peng; Sodt, Alexander J; Shao, Yihan; König, Gerhard; Brooks, Bernard R

    2014-10-14

    The calculations of potential of mean force along complex chemical reactions or rare events pathways are of great interest because of their importance for many areas in chemistry, molecular biology, and material science. The major difficulty for free energy calculations comes from the great computational cost for adequate sampling of the system in high-energy regions, especially close to the reaction transition state. Here, we present a method, called FEG-RBD, in which the free energy gradients were obtained from rigid body dynamics simulations. Then the free energy gradients were integrated along a reference reaction pathway to calculate free energy profiles. In a given system, the reaction coordinates defining a subset of atoms (e.g., a solute, or the quantum mechanics (QM) region of a quantum mechanics/molecular mechanics simulation) are selected to form a rigid body during the simulation. The first-order derivatives (gradients) of the free energy with respect to the reaction coordinates are obtained through the integration of constraint forces within the rigid body. Each structure along the reference reaction path is separately subjected to such a rigid body simulation. The individual free energy gradients are integrated along the reference pathway to obtain the free energy profile. Test cases provided demonstrate both the strengths and weaknesses of the FEG-RBD method. The most significant benefit of this method comes from the fast convergence rate of the free energy gradient using rigid-body constraints instead of restraints. A correction to the free energy due to approximate relaxation of the rigid-body constraint is estimated and discussed. A comparison with umbrella sampling using a simple test case revealed the improved sampling efficiency of FEG-RBD by a factor of 4 on average. The enhanced efficiency makes this method effective for calculating the free energy of complex chemical reactions when the reaction coordinate can be unambiguously defined by a

  18. Computation studies into architecture and energy transfer properties of photosynthetic units from filamentous anoxygenic phototrophs

    SciTech Connect

    Linnanto, Juha Matti; Freiberg, Arvi

    2014-10-06

    We have used different computational methods to study structural architecture, and light-harvesting and energy transfer properties of the photosynthetic unit of filamentous anoxygenic phototrophs. Due to the huge number of atoms in the photosynthetic unit, a combination of atomistic and coarse methods was used for electronic structure calculations. The calculations reveal that the light energy absorbed by the peripheral chlorosome antenna complex transfers efficiently via the baseplate and the core B808–866 antenna complexes to the reaction center complex, in general agreement with the present understanding of this complex system.

  19. Bessel Fourier Orientation Reconstruction (BFOR): An Analytical Diffusion Propagator Reconstruction for Hybrid Diffusion Imaging and Computation of q-Space Indices

    PubMed Central

    Hosseinbor, A. Pasha; Chung, Moo K.; Wu, Yu-Chien; Alexander, Andrew L.

    2012-01-01

    The ensemble average propagator (EAP) describes the 3D average diffusion process of water molecules, capturing both its radial and angular contents. The EAP can thus provide richer information about complex tissue microstructure properties than the orientation distribution function (ODF), an angular feature of the EAP. Recently, several analytical EAP reconstruction schemes for multiple q-shell acquisitions have been proposed, such as diffusion propagator imaging (DPI) and spherical polar Fourier imaging (SPFI). In this study, a new analytical EAP reconstruction method is proposed, called Bessel Fourier orientation reconstruction (BFOR), whose solution is based on heat equation estimation of the diffusion signal for each shell acquisition, and is validated on both synthetic and real datasets. A significant portion of the paper is dedicated to comparing BFOR, SPFI, and DPI using hybrid, non-Cartesian sampling for multiple b-value acquisitions. Ways to mitigate the effects of Gibbs ringing on EAP reconstruction are also explored. In addition to analytical EAP reconstruction, the aforementioned modeling bases can be used to obtain rotationally invariant q-space indices of potential clinical value, an avenue which has not yet been thoroughly explored. Three such measures are computed: zero-displacement probability (Po), mean squared displacement (MSD), and generalized fractional anisotropy (GFA). PMID:22963853

  20. Materials for Alternative Energies: Computational Materials Discovery and Crystal Structure Prediction

    NASA Astrophysics Data System (ADS)

    Wolverton, Chris

    2013-03-01

    Many of the key technological problems associated with alternative energies may be traced back to the lack of suitable materials. The materials discovery process may be greatly aided by the use of computational methods, particular those atomistic methods based on density functional theory. In this talk, we present an overview of recent work on energy-related materials from density-functional based approaches. We have developed novel computational tools which enable accurate prediction of crystal structures for new materials (using both Monte Carlo and Genetic Algorithm based approaches), materials discovery via high-throughput, data mining techniques, and automated phase diagram calculations. We highlight applications in the area of Li battery materials and hydrogen storage materials.

  1. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    SciTech Connect

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.

  2. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    DOE PAGES

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

  3. Computational model for noncontact atomic force microscopy: energy dissipation of cantilever.

    PubMed

    Senda, Yasuhiro; Blomqvist, Janne; Nieminen, Risto M

    2016-09-21

    We propose a computational model for noncontact atomic force microscopy (AFM) in which the atomic force between the cantilever tip and the surface is calculated using a molecular dynamics method, and the macroscopic motion of the cantilever is modeled by an oscillating spring. The movement of atoms in the tip and surface is connected with the oscillating spring using a recently developed coupling method. In this computational model, the oscillation energy is dissipated, as observed in AFM experiments. We attribute this dissipation to the hysteresis and nonconservative properties of the interatomic force that acts between the atoms in the tip and sample surface. The dissipation rate strongly depends on the parameters used in the computational model.

  4. Computer simulation for time optimal or energy optimal attitude control of spin-stabilized spacecraft.

    NASA Technical Reports Server (NTRS)

    Woolley, R. D.; Werking, R. D.

    1973-01-01

    An original technique for determining the optimal magnetic torque strategy for control of the attitude of spin stabilized spacecraft is presented. By employing Lagrange multipliers and the Calculus of Variations, optimal control equations are derived which define minimum time and minimum energy attitude maneuvers. Computer program algorithms to numerically solve these optimal control equations are also described. The performance of this technique is compared with a commonly employed planning method.

  5. A digital computer simulation and study of a direct-energy-transfer power-conditioning system

    NASA Technical Reports Server (NTRS)

    Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

    1974-01-01

    A digital computer simulation technique, which can be used to study such composite power-conditioning systems, was applied to a spacecraft direct-energy-transfer power-processing system. The results obtained duplicate actual system performance with considerable accuracy. The validity of the approach and its usefulness in studying various aspects of system performance such as steady-state characteristics and transient responses to severely varying operating conditions are demonstrated experimentally.

  6. Comparative Validity and Reproducibility Study of Various Landmark-Oriented Reference Planes in 3-Dimensional Computed Tomographic Analysis for Patients Receiving Orthognathic Surgery

    PubMed Central

    Lin, Hsiu-Hsia; Chuang, Ya-Fang; Weng, Jing-Ling; Lo, Lun-Jou

    2015-01-01

    Background Three-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification. Materials and Methods Preoperative and postoperative cone-beam computed tomographic images of patients who had undergone orthognathic surgery were collected. Landmark-oriented reference planes including the Frankfort horizontal plane (FHP) and the lateral semicircular canal plane (LSP) were established. Four FHPs were defined by selecting 3 points from the orbitale, porion, or midpoint of paired points. The LSP passed through both the lateral semicircular canal points and nasion. The distances between the maxillary or mandibular teeth and the reference planes were measured, and the differences between the 2 sides were calculated and compared. The precision in locating the landmarks was evaluated by performing repeated tests, and the intraobserver reproducibility and interobserver reliability were assessed. Results A total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners. Conclusions The

  7. Computer code to predict the heat of explosion of high energy materials.

    PubMed

    Muthurajan, H; Sivabalan, R; Pon Saravanan, N; Talawar, M B

    2009-01-30

    The computational approach to the thermochemical changes involved in the process of explosion of a high energy materials (HEMs) vis-à-vis its molecular structure aids a HEMs chemist/engineers to predict the important thermodynamic parameters such as heat of explosion of the HEMs. Such a computer-aided design will be useful in predicting the performance of a given HEM as well as in conceiving futuristic high energy molecules that have significant potential in the field of explosives and propellants. The software code viz., LOTUSES developed by authors predicts various characteristics of HEMs such as explosion products including balanced explosion reactions, density of HEMs, velocity of detonation, CJ pressure, etc. The new computational approach described in this paper allows the prediction of heat of explosion (DeltaH(e)) without any experimental data for different HEMs, which are comparable with experimental results reported in literature. The new algorithm which does not require any complex input parameter is incorporated in LOTUSES (version 1.5) and the results are presented in this paper. The linear regression analysis of all data point yields the correlation coefficient R(2)=0.9721 with a linear equation y=0.9262x+101.45. The correlation coefficient value 0.9721 reveals that the computed values are in good agreement with experimental values and useful for rapid hazard assessment of energetic materials.

  8. Verification of a VRF Heat Pump Computer Model in EnergyPlus

    SciTech Connect

    Nigusse, Bereket; Raustad, Richard

    2013-06-15

    This paper provides verification results of the EnergyPlus variable refrigerant flow (VRF) heat pump computer model using manufacturer's performance data. The paper provides an overview of the VRF model, presents the verification methodology, and discusses the results. The verification provides quantitative comparison of full and part-load performance to manufacturer's data in cooling-only and heating-only modes of operation. The VRF heat pump computer model uses dual range bi-quadratic performance curves to represent capacity and Energy Input Ratio (EIR) as a function of indoor and outdoor air temperatures, and dual range quadratic performance curves as a function of part-load-ratio for modeling part-load performance. These performance curves are generated directly from manufacturer's published performance data. The verification compared the simulation output directly to manufacturer's performance data, and found that the dual range equation fit VRF heat pump computer model predicts the manufacturer's performance data very well over a wide range of indoor and outdoor temperatures and part-load conditions. The predicted capacity and electric power deviations are comparbale to equation-fit HVAC computer models commonly used for packaged and split unitary HVAC equipment.

  9. A novel cost based model for energy consumption in cloud computing.

    PubMed

    Horri, A; Dastghaibyfard, Gh

    2015-01-01

    Cloud data centers consume enormous amounts of electrical energy. To support green cloud computing, providers also need to minimize cloud infrastructure energy consumption while conducting the QoS. In this study, for cloud environments an energy consumption model is proposed for time-shared policy in virtualization layer. The cost and energy usage of time-shared policy were modeled in the CloudSim simulator based upon the results obtained from the real system and then proposed model was evaluated by different scenarios. In the proposed model, the cache interference costs were considered. These costs were based upon the size of data. The proposed model was implemented in the CloudSim simulator and the related simulation results indicate that the energy consumption may be considerable and that it can vary with different parameters such as the quantum parameter, data size, and the number of VMs on a host. Measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. Also, measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment.

  10. Material differentiation in forensic radiology with single-source dual-energy computed tomography.

    PubMed

    Ruder, Thomas D; Thali, Yannick; Bolliger, Stephan A; Somaini-Mathier, Sandra; Thali, Michael J; Hatch, Gary M; Schindera, Sebastian T

    2013-06-01

    The goal of this study was to investigate the use of dual-energy computed tomography (CT) in differentiating frequently encountered foreign material on CT images using a standard single-source CT scanner. We scanned 20 different, forensically relevant materials at two X-Ray energy levels (80 and 130 kVp) on CT. CT values were measured in each object at both energy levels. Intraclass correlation coefficient (ICC) was used to determine intra-reader reliability. Analysis of variance (ANOVA) was performed to assess significance levels between X-Ray attenuation at 80 and 130 kVp. T test was used to investigate significance levels between mean HU values of individual object pairings at single energy levels of 80 and 130 kVp, respectively. ANOVA revealed that the difference in attenuation between beam energies of 80 kVp compared to 130 kVp was statistically significant (p < 0.005) for all materials except brass and lead. ICC was excellent at 80 kVp (0.999, p < 0.001) and at 130 kVp (0.998, p < 0.001). T test showed that using single energy levels of 80 and 130 kVp respectively 181/190 objects pairs could be differentiated from one another based on HU measurements. Using the combined information from both energy levels, 189/190 object pairs could be differentiated. Scanning with different energy levels is a simple way to apply dual-energy technique on a regular single-energy CT and improves the ability to differentiate foreign bodies with CT, based on their attenuation values.

  11. Computational issues in complex water-energy optimization problems: Time scales, parameterizations, objectives and algorithms

    NASA Astrophysics Data System (ADS)

    Efstratiadis, Andreas; Tsoukalas, Ioannis; Kossieris, Panayiotis; Karavokiros, George; Christofides, Antonis; Siskos, Alexandros; Mamassis, Nikos; Koutsoyiannis, Demetris

    2015-04-01

    Modelling of large-scale hybrid renewable energy systems (HRES) is a challenging task, for which several open computational issues exist. HRES comprise typical components of hydrosystems (reservoirs, boreholes, conveyance networks, hydropower stations, pumps, water demand nodes, etc.), which are dynamically linked with renewables (e.g., wind turbines, solar parks) and energy demand nodes. In such systems, apart from the well-known shortcomings of water resources modelling (nonlinear dynamics, unknown future inflows, large number of variables and constraints, conflicting criteria, etc.), additional complexities and uncertainties arise due to the introduction of energy components and associated fluxes. A major difficulty is the need for coupling two different temporal scales, given that in hydrosystem modeling, monthly simulation steps are typically adopted, yet for a faithful representation of the energy balance (i.e. energy production vs. demand) a much finer resolution (e.g. hourly) is required. Another drawback is the increase of control variables, constraints and objectives, due to the simultaneous modelling of the two parallel fluxes (i.e. water and energy) and their interactions. Finally, since the driving hydrometeorological processes of the integrated system are inherently uncertain, it is often essential to use synthetically generated input time series of large length, in order to assess the system performance in terms of reliability and risk, with satisfactory accuracy. To address these issues, we propose an effective and efficient modeling framework, key objectives of which are: (a) the substantial reduction of control variables, through parsimonious yet consistent parameterizations; (b) the substantial decrease of computational burden of simulation, by linearizing the combined water and energy allocation problem of each individual time step, and solve each local sub-problem through very fast linear network programming algorithms, and (c) the substantial

  12. Computational scheme for pH-dependent binding free energy calculation with explicit solvent.

    PubMed

    Lee, Juyong; Miller, Benjamin T; Brooks, Bernard R

    2016-01-01

    We present a computational scheme to compute the pH-dependence of binding free energy with explicit solvent. Despite the importance of pH, the effect of pH has been generally neglected in binding free energy calculations because of a lack of accurate methods to model it. To address this limitation, we use a constant-pH methodology to obtain a true ensemble of multiple protonation states of a titratable system at a given pH and analyze the ensemble using the Bennett acceptance ratio (BAR) method. The constant pH method is based on the combination of enveloping distribution sampling (EDS) with the Hamiltonian replica exchange method (HREM), which yields an accurate semi-grand canonical ensemble of a titratable system. By considering the free energy change of constraining multiple protonation states to a single state or releasing a single protonation state to multiple states, the pH dependent binding free energy profile can be obtained. We perform benchmark simulations of a host-guest system: cucurbit[7]uril (CB[7]) and benzimidazole (BZ). BZ experiences a large pKa shift upon complex formation. The pH-dependent binding free energy profiles of the benchmark system are obtained with three different long-range interaction calculation schemes: a cutoff, the particle mesh Ewald (PME), and the isotropic periodic sum (IPS) method. Our scheme captures the pH-dependent behavior of binding free energy successfully. Absolute binding free energy values obtained with the PME and IPS methods are consistent, while cutoff method results are off by 2 kcal mol(-1) . We also discuss the characteristics of three long-range interaction calculation methods for constant-pH simulations.

  13. Compare Energy Use in Variable Refrigerant Flow Heat Pumps Field Demonstration and Computer Model

    SciTech Connect

    Sharma, Chandan; Raustad, Richard

    2013-07-01

    Variable Refrigerant Flow (VRF) heat pumps are often regarded as energy efficient air-conditioning systems which offer electricity savings as well as reduction in peak electric demand while providing improved individual zone setpoint control. One of the key advantages of VRF systems is minimal duct losses which provide significant reduction in energy use and duct space. However, there is limited data available to show their actual performance in the field. Since VRF systems are increasingly gaining market share in the US, it is highly desirable to have more actual field performance data of these systems. An effort was made in this direction to monitor VRF system performance over an extended period of time in a US national lab test facility. Due to increasing demand by the energy modeling community, an empirical model to simulate VRF systems was implemented in the building simulation program EnergyPlus. This paper presents the comparison of energy consumption as measured in the national lab and as predicted by the program. For increased accuracy in the comparison, a customized weather file was created by using measured outdoor temperature and relative humidity at the test facility. Other inputs to the model included building construction, VRF system model based on lab measured performance, occupancy of the building, lighting/plug loads, and thermostat set-points etc. Infiltration model inputs were adjusted in the beginning to tune the computer model and then subsequent field measurements were compared to the simulation results. Differences between the computer model results and actual field measurements are discussed. The computer generated VRF performance closely resembled the field measurements.

  14. Quantitative material decomposition using spectral computed tomography with an energy-resolved photon-counting detector.

    PubMed

    Lee, Seungwan; Choi, Yu-Na; Kim, Hee-Joung

    2014-09-21

    Dual-energy computed tomography (CT) techniques have been used to decompose materials and characterize tissues according to their physical and chemical compositions. However, these techniques are hampered by the limitations of conventional x-ray detectors operated in charge integrating mode. Energy-resolved photon-counting detectors provide spectral information from polychromatic x-rays using multiple energy thresholds. These detectors allow simultaneous acquisition of data in different energy ranges without spectral overlap, resulting in more efficient material decomposition and quantification for dual-energy CT. In this study, a pre-reconstruction dual-energy CT technique based on volume conservation was proposed for three-material decomposition. The technique was combined with iterative reconstruction algorithms by using a ray-driven projector in order to improve the quality of decomposition images and reduce radiation dose. A spectral CT system equipped with a CZT-based photon-counting detector was used to implement the proposed dual-energy CT technique. We obtained dual-energy images of calibration and three-material phantoms consisting of low atomic number materials from the optimal energy bins determined by Monte Carlo simulations. The material decomposition process was accomplished by both the proposed and post-reconstruction dual-energy CT techniques. Linear regression and normalized root-mean-square error (NRMSE) analyses were performed to evaluate the quantitative accuracy of decomposition images. The calibration accuracy of the proposed dual-energy CT technique was higher than that of the post-reconstruction dual-energy CT technique, with fitted slopes of 0.97-1.01 and NRMSEs of 0.20-4.50% for all basis materials. In the three-material phantom study, the proposed dual-energy CT technique decreased the NRMSEs of measured volume fractions by factors of 0.17-0.28 compared to the post-reconstruction dual-energy CT technique. It was concluded that the

  15. Computing conformational free energy differences in explicit solvent: An efficient thermodynamic cycle using an auxiliary potential and a free energy functional constructed from the end points.

    PubMed

    Harris, Robert C; Deng, Nanjie; Levy, Ronald M; Ishizuka, Ryosuke; Matubayasi, Nobuyuki

    2016-12-23

    Many biomolecules undergo conformational changes associated with allostery or ligand binding. Observing these changes in computer simulations is difficult if their timescales are long. These calculations can be accelerated by observing the transition on an auxiliary free energy surface with a simpler Hamiltonian and connecting this free energy surface to the target free energy surface with free energy calculations. Here, we show that the free energy legs of the cycle can be replaced with energy representation (ER) density functional approximations. We compute: (1) The conformational free energy changes for alanine dipeptide transitioning from the right-handed free energy basin to the left-handed basin and (2) the free energy difference between the open and closed conformations of β-cyclodextrin, a "host" molecule that serves as a model for molecular recognition in host-guest binding. β-cyclodextrin contains 147 atoms compared to 22 atoms for alanine dipeptide, making β-cyclodextrin a large molecule for which to compute solvation free energies by free energy perturbation or integration methods and the largest system for which the ER method has been compared to exact free energy methods. The ER method replaced the 28 simulations to compute each coupling free energy with two endpoint simulations, reducing the computational time for the alanine dipeptide calculation by about 70% and for the β-cyclodextrin by > 95%. The method works even when the distribution of conformations on the auxiliary free energy surface differs substantially from that on the target free energy surface, although some degree of overlap between the two surfaces is required. © 2016 Wiley Periodicals, Inc.

  16. Computer Modeling VRF Heat Pumps in Commercial Buildings using EnergyPlus

    SciTech Connect

    Raustad, Richard

    2013-07-01

    Variable Refrigerant Flow (VRF) heat pumps are increasingly used in commercial buildings in the United States. Monitored energy use of field installations have shown, in some cases, savings exceeding 30% compared to conventional heating, ventilating, and air-conditioning (HVAC) systems. A simulation study was conducted to identify the installation or operational characteristics that lead to energy savings for VRF systems. The study used the Department of Energy EnergyPlus? building simulation software and four reference building models. Computer simulations were performed in eight U.S. climate zones. The baseline reference HVAC system incorporated packaged single-zone direct-expansion cooling with gas heating (PSZ-AC) or variable-air-volume systems (VAV with reheat). An alternate baseline HVAC system using a heat pump (PSZ-HP) was included for some buildings to directly compare gas and electric heating results. These baseline systems were compared to a VRF heat pump model to identify differences in energy use. VRF systems combine multiple indoor units with one or more outdoor unit(s). These systems move refrigerant between the outdoor and indoor units which eliminates the need for duct work in most cases. Since many applications install duct work in unconditioned spaces, this leads to installation differences between VRF systems and conventional HVAC systems. To characterize installation differences, a duct heat gain model was included to identify the energy impacts of installing ducts in unconditioned spaces. The configuration of variable refrigerant flow heat pumps will ultimately eliminate or significantly reduce energy use due to duct heat transfer. Fan energy is also studied to identify savings associated with non-ducted VRF terminal units. VRF systems incorporate a variable-speed compressor which may lead to operational differences compared to single-speed compression systems. To characterize operational differences, the computer model performance curves used

  17. OpenGeoSys: Performance-Oriented Computational Methods for Numerical Modeling of Flow in Large Hydrogeological Systems

    NASA Astrophysics Data System (ADS)

    Naumov, D.; Fischer, T.; Böttcher, N.; Watanabe, N.; Walther, M.; Rink, K.; Bilke, L.; Shao, H.; Kolditz, O.

    2014-12-01

    OpenGeoSys (OGS) is a scientific open source code for numerical simulation of thermo-hydro-mechanical-chemical processes in porous and fractured media. Its basic concept is to provide a flexible numerical framework for solving multi-field problems for applications in geoscience and hydrology as e.g. for CO2 storage applications, geothermal power plant forecast simulation, salt water intrusion, water resources management, etc. Advances in computational mathematics have revolutionized the variety and nature of the problems that can be addressed by environmental scientists and engineers nowadays and an intensive code development in the last years enables in the meantime the solutions of much larger numerical problems and applications. However, solving environmental processes along the water cycle at large scales, like for complete catchment or reservoirs, stays computationally still a challenging task. Therefore, we started a new OGS code development with focus on execution speed and parallelization. In the new version, a local data structure concept improves the instruction and data cache performance by a tight bundling of data with an element-wise numerical integration loop. Dedicated analysis methods enable the investigation of memory-access patterns in the local and global assembler routines, which leads to further data structure optimization for an additional performance gain. The concept is presented together with a technical code analysis of the recent development and a large case study including transient flow simulation in the unsaturated / saturated zone of the Thuringian Syncline, Germany. The analysis is performed on a high-resolution mesh (up to 50M elements) with embedded fault structures.

  18. Network Computing Infrastructure to Share Tools and Data in Global Nuclear Energy Partnership

    NASA Astrophysics Data System (ADS)

    Kim, Guehee; Suzuki, Yoshio; Teshima, Naoya

    CCSE/JAEA (Center for Computational Science and e-Systems/Japan Atomic Energy Agency) integrated a prototype system of a network computing infrastructure for sharing tools and data to support the U.S. and Japan collaboration in GNEP (Global Nuclear Energy Partnership). We focused on three technical issues to apply our information process infrastructure, which are accessibility, security, and usability. In designing the prototype system, we integrated and improved both network and Web technologies. For the accessibility issue, we adopted SSL-VPN (Security Socket Layer-Virtual Private Network) technology for the access beyond firewalls. For the security issue, we developed an authentication gateway based on the PKI (Public Key Infrastructure) authentication mechanism to strengthen the security. Also, we set fine access control policy to shared tools and data and used shared key based encryption method to protect tools and data against leakage to third parties. For the usability issue, we chose Web browsers as user interface and developed Web application to provide functions to support sharing tools and data. By using WebDAV (Web-based Distributed Authoring and Versioning) function, users can manipulate shared tools and data through the Windows-like folder environment. We implemented the prototype system in Grid infrastructure for atomic energy research: AEGIS (Atomic Energy Grid Infrastructure) developed by CCSE/JAEA. The prototype system was applied for the trial use in the first period of GNEP.

  19. Computer simulation of energy use, greenhouse gas emissions, and process economics of the fluid milk process.

    PubMed

    Tomasula, P M; Yee, W C F; McAloon, A J; Nutter, D W; Bonnaillie, L M

    2013-05-01

    Energy-savings measures have been implemented in fluid milk plants to lower energy costs and the energy-related carbon dioxide (CO2) emissions. Although these measures have resulted in reductions in steam, electricity, compressed air, and refrigeration use of up to 30%, a benchmarking framework is necessary to examine the implementation of process-specific measures that would lower energy use, costs, and CO2 emissions even further. In this study, using information provided by the dairy industry and equipment vendors, a customizable model of the fluid milk process was developed for use in process design software to benchmark the electrical and fuel energy consumption and CO2 emissions of current processes. It may also be used to test the feasibility of new processing concepts to lower energy and CO2 emissions with calculation of new capital and operating costs. The accuracy of the model in predicting total energy usage of the entire fluid milk process and the pasteurization step was validated using available literature and industry energy data. Computer simulation of small (40.0 million L/yr), medium (113.6 million L/yr), and large (227.1 million L/yr) processing plants predicted the carbon footprint of milk, defined as grams of CO2 equivalents (CO2e) per kilogram of packaged milk, to within 5% of the value of 96 g of CO 2e/kg of packaged milk obtained in an industry-conducted life cycle assessment and also showed, in agreement with the same study, that plant size had no effect on the carbon footprint of milk but that larger plants were more cost effective in producing milk. Analysis of the pasteurization step showed that increasing the percentage regeneration of the pasteurizer from 90 to 96% would lower its thermal energy use by almost 60% and that implementation of partial homogenization would lower electrical energy use and CO2e emissions of homogenization by 82 and 5.4%, respectively. It was also demonstrated that implementation of steps to lower non

  20. Fast computation of high energy elastic collision scattering angle for electric propulsion plume simulation

    NASA Astrophysics Data System (ADS)

    Araki, Samuel J.

    2016-11-01

    In the plumes of Hall thrusters and ion thrusters, high energy ions experience elastic collisions with slow neutral atoms. These collisions involve a process of momentum exchange, altering the initial velocity vectors of the collision pair. In addition to the momentum exchange process, ions and atoms can exchange electrons, resulting in slow charge-exchange ions and fast atoms. In these simulations, it is particularly important to accurately perform computations of ion-atom elastic collisions in determining the plume current profile and assessing the integration of spacecraft components. The existing models are currently capable of accurate calculation but are not fast enough such that the calculation can be a bottleneck of plume simulations. This study investigates methods to accelerate an ion-atom elastic collision calculation that includes both momentum- and charge-exchange processes. The scattering angles are pre-computed through a classical approach with ab initio spin-orbit free potential and are stored in a two-dimensional array as functions of impact parameter and energy. When performing a collision calculation for an ion-atom pair, the scattering angle is computed by a table lookup and multiple linear interpolations, given the relative energy and randomly determined impact parameter. In order to further accelerate the calculations, the number of collision calculations is reduced by properly defining two cut-off cross-sections for the elastic scattering. In the MCC method, the target atom needs to be sampled; however, it is confirmed that initial target atom velocity does not play a significant role in typical electric propulsion plume simulations such that the sampling process is unnecessary. With these implementations, the computational run-time to perform a collision calculation is reduced significantly compared to previous methods, while retaining the accuracy of the high fidelity models.

  1. US-MEXICAN COLLABORATION IN COMPUTATIONAL RESEARCH FOR THE PEACEFUL USE OF NUCLEAR ENERGY

    SciTech Connect

    R. PERRY; W. CHARLTON; ET AL

    1999-07-01

    Under the auspices of the ''Memorandum of Understanding for the Exchange of Technical Information and for Cooperation in the Field of Peaceful Uses of Nuclear Energy'' between the National Institute of Nuclear Research of Mexico (ININ) and the Los Alamos National Laboratory (LANL), scientists and engineers from ININ met and collaborated with scientists at LANL. The collaboration was sponsored by the US Department of Energy as part of its ''Sister Laboratories'' program. In this weeklong meeting, these scientists and engineers carried out mutual consultation and cooperative efforts in the field of computational research in nuclear power. Three main areas for technical collaboration were discussed: (a) establishment of electronic access to LANL open computational facilities and reactor physics codes from ININ, (b) calculation of radiation damage to BWR reactor vessels, and (c) calculation of BWR burnup for MOX fuel. These three tasks were successfully completed during the weeklong meeting between the laboratory scientists. The discussion, held at LANL in March 1999, involved ten LANL specialists and three ININ specialists. In addition, several computer technicians provided the necessary support for the utilization of the SUN computers, which were setup for the seminars. Discussions between team members occupied about half of the visit. Mixed Oxide (MOX) assembly models were developed and calculations made using HELIOS and MCNP the remainder of the time. As a result of the collaboration, the scientists from ININ returned to the institute and immediately began using the computational facilities at LANL for further MOX assembly calculations. As a result of the meeting, ININ is providing expert advice for the thermal hydraulic calculations for a similar cooperative program between Peruvian and LANL. The three areas of cooperation will be discussed in detail in this paper. Sample results of the MOX calculations at ININ will also be presented.

  2. A Computational Model for Predicting Experimental RNA Nearest-Neighbor Free Energy Rankings: Inosine•Uridine Pairs.

    PubMed

    Jolley, Elizabeth A; Lewis, Michael; Znosko, Brent M

    2015-10-16

    A computational model for predicting RNA nearest neighbor free energy rankings has been expanded to include the nonstandard nucleotide inosine. The model uses average fiber diffraction data and molecular dynamic simulations to generate input geometries for Quantum mechanic calculations. This resulted in calculated intrastrand stacking, interstrand stacking, and hydrogen bonding energies that were combined to give total binding energies. Total binding energies for RNA dimer duplexes containing inosine were ranked and compared to experimentally determined free energy ranks for RNA duplexes containing inosine. Statistical analysis showed significant agreement between the computationally determined ranks and the experimentally determined ranks.

  3. Orientational disorder in Na/sub 3/PSO/sub 3/. 12H/sub 2/O x-ray diffraction and computer simulation studies

    SciTech Connect

    Goldstein, B.M.

    1982-01-01

    Na/sub 3/PSO/sub 3/.12H/sub 2/O crystallizes in the trigonal space group R3c with a = 9.061(2), c = 34.34(2) A (hexagonal axes), Z = 6, V = 2441.6 A/sup 2/, D/sub c/ = 1/612 MgM/sup -3/, ..mu.. (Mo k/sup -/2chemically bond) = 0.45 mm/sup -1/, F(000) = 1248. Final R = 0.051 for 326 independent observed reflections. The structure consists of discrete (PSO/sub 3/)/sup 3 -/ anions and (Na/sub 3/)/sup 3 +/(H/sub 2/O)/sub 12/ groups. All Na, P, and S atoms lie on the unique axis. Hydrogen bonds involving all water molecules link the cation complexes both directly and through water-anion interactions. The (PSO/sub 3/)/sup 3 -/ anions are disordered with equal occupancy over two orientations related by the point symmetry 32. A model has been developed to simulate this type of disorder. It assumes that the occupation of alternative anion orientations occurs during crystal growth. This process is simulated by the sequential addition of Na/sub 3/PSO/sub 3/.12H/sub 2/O units to randomly selected nearest neighbor lattice sites. Each unit either binds to the lattice in one of four configurations or does not bind. The probability of occupation of each of these states is given by a canonical distribution. The choice of state is determined by comparison of the distribution to a random number. The energy of the unit in each bound state is calculated using electrostatic, induction, hydrogen bond, dispersion and repulsion interactions. The energy of the nonbound state is a model parameter. Once a unit binds to the lattice, it cannot change its parameter. Once a unit binds to the lattice, it cannot change its configuration, reflecting the non-cooperative nature of a static disorder.

  4. Computational modelling of left-ventricular diastolic mechanics: effect of fibre orientation and right-ventricle topology.

    PubMed

    Palit, Arnab; Bhudia, Sunil K; Arvanitis, Theodoros N; Turley, Glen A; Williams, Mark A

    2015-02-26

    Majority of heart failure patients who suffer from diastolic dysfunction retain normal systolic pump action. The dysfunction remodels the myocardial fibre structure of left-ventricle (LV), changing its regular diastolic behaviour. Existing LV diastolic models ignored the effects of right-ventricular (RV) deformation, resulting in inaccurate strain analysis of LV wall during diastole. This paper, for the first time, proposes a numerical approach to investigate the effect of fibre-angle distribution and RV deformation on LV diastolic mechanics. A finite element modelling of LV passive inflation was carried out, using structure-based orthotropic constitutive law. Rule-based fibre architecture was assigned on a bi-ventricular (BV) geometry constructed from non-invasive imaging of human heart. The effect of RV deformation on LV diastolic mechanics was investigated by comparing the results predicted by BV and single LV model constructed from the same image data. Results indicated an important influence of RV deformation which led to additional LV passive inflation and increase of average fibre and sheet stress-strain in LV wall during diastole. Sensitivity of LV passive mechanics to the changes in the fibre distribution was also examined. The study revealed that LV diastolic volume increased when fibres were aligned more towards LV longitudinal axis. Changes in fibre angle distribution significantly altered fibre stress-strain distribution of LV wall. The simulation results strongly suggest that patient-specific fibre structure and RV deformation play very important roles in LV diastolic mechanics and should be accounted for in computational modelling for improved understanding of the LV mechanics under normal and pathological conditions.

  5. Computer Controlled Portable Greenhouse Climate Control System for Enhanced Energy Efficiency

    NASA Astrophysics Data System (ADS)

    Datsenko, Anthony; Myer, Steve; Petties, Albert; Hustek, Ryan; Thompson, Mark

    2010-04-01

    This paper discusses a student project at Kettering University focusing on the design and construction of an energy efficient greenhouse climate control system. In order to maintain acceptable temperatures and stabilize temperature fluctuations in a portable plastic greenhouse economically, a computer controlled climate control system was developed to capture and store thermal energy incident on the structure during daylight periods and release the stored thermal energy during dark periods. The thermal storage mass for the greenhouse system consisted of a water filled base unit. The heat exchanger consisted of a system of PVC tubing. The control system used a programmable LabView computer interface to meet functional specifications that minimized temperature fluctuations and recorded data during operation. The greenhouse was a portable sized unit with a 5' x 5' footprint. Control input sensors were temperature, water level, and humidity sensors and output control devices were fan actuating relays and water fill solenoid valves. A Graphical User Interface was developed to monitor the system, set control parameters, and to provide programmable data recording times and intervals.

  6. Worldline approach for numerical computation of electromagnetic Casimir energies: Scalar field coupled to magnetodielectric media

    NASA Astrophysics Data System (ADS)

    Mackrory, Jonathan B.; Bhattacharya, Tanmoy; Steck, Daniel A.

    2016-10-01

    We present a worldline method for the calculation of Casimir energies for scalar fields coupled to magnetodielectric media. The scalar model we consider may be applied in arbitrary geometries, and it corresponds exactly to one polarization of the electromagnetic field in planar layered media. Starting from the field theory for electromagnetism, we work with the two decoupled polarizations in planar media and develop worldline path integrals, which represent the two polarizations separately, for computing both Casimir and Casimir-Polder potentials. We then show analytically that the path integrals for the transverse-electric polarization coupled to a dielectric medium converge to the proper solutions in certain special cases, including the Casimir-Polder potential of an atom near a planar interface, and the Casimir energy due to two planar interfaces. We also evaluate the path integrals numerically via Monte Carlo path-averaging for these cases, studying the convergence and performance of the resulting computational techniques. While these scalar methods are only exact in particular geometries, they may serve as an approximation for Casimir energies for the vector electromagnetic field in other geometries.

  7. Strategy using three layers of surface charge for computing solvation free energy of ions.

    PubMed

    Yang, Pei-Kun

    2013-12-31

    Continuum solvent model is the common used strategy for computing the solvation free energy. However, the dielectric polarization from Gauss's law differs from that obtained from molecular dynamics simulations. To mimic the dielectric polarization surrounding a solute in molecular dynamics simulations, the first-shell water molecule was modeled using a charge distribution of TIP4P molecule in a hard sphere. The dielectric polarization of the first-shell water was modeled as a pair of surface charge layers with a fixed distance between them, but with variable, equal, and opposite charge magnitudes that respond to the electric field on the first-shell water. The water outside the first shell water is treated as a bulk solvent, and the electric effect of the bulk solvent can be modeled as a surface charge. Based on this strategy, the analytical solution describing the solvation free energy of ions was derived, and the values of computed solvation free energy were compared to the values of experiments.

  8. Modulation of folding energy landscape by charge-charge interactions: linking experiments with computational modeling.

    PubMed

    Tzul, Franco O; Schweiker, Katrina L; Makhatadze, George I

    2015-01-20

    The kinetics of folding-unfolding of a structurally diverse set of four proteins optimized for thermodynamic stability by rational redesign of surface charge-charge interactions is characterized experimentally. The folding rates are faster for designed variants compared with their wild-type proteins, whereas the unfolding rates are largely unaffected. A simple structure-based computational model, which incorporates the Debye-Hückel formalism for the electrostatics, was used and found to qualitatively recapitulate the experimental results. Analysis of the energy landscapes of the designed versus wild-type proteins indicates the differences in refolding rates may be correlated with the degree of frustration of their respective energy landscapes. Our simulations indicate that naturally occurring wild-type proteins have frustrated folding landscapes due to the surface electrostatics. Optimization of the surface electrostatics seems to remove some of that frustration, leading to enhanced formation of native-like contacts in the transition-state ensembles (TSE) and providing a less frustrated energy landscape between the unfolded and TS ensembles. Macroscopically, this results in faster folding rates. Furthermore, analyses of pairwise distances and radii of gyration suggest that the less frustrated energy landscapes for optimized variants are a result of more compact unfolded and TS ensembles. These findings from our modeling demonstrates that this simple model may be used to: (i) gain a detailed understanding of charge-charge interactions and their effects on modulating the energy landscape of protein folding and (ii) qualitatively predict the kinetic behavior of protein surface electrostatic interactions.

  9. Influence of Finite Element Software on Energy Release Rates Computed Using the Virtual Crack Closure Technique

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald; Goetze, Dirk; Ransom, Jonathon (Technical Monitor)

    2006-01-01

    Strain energy release rates were computed along straight delamination fronts of Double Cantilever Beam, End-Notched Flexure and Single Leg Bending specimens using the Virtual Crack Closure Technique (VCCT). Th e results were based on finite element analyses using ABAQUS# and ANSYS# and were calculated from the finite element results using the same post-processing routine to assure a consistent procedure. Mixed-mode strain energy release rates obtained from post-processing finite elem ent results were in good agreement for all element types used and all specimens modeled. Compared to previous studies, the models made of s olid twenty-node hexahedral elements and solid eight-node incompatible mode elements yielded excellent results. For both codes, models made of standard brick elements and elements with reduced integration did not correctly capture the distribution of the energy release rate acr oss the width of the specimens for the models chosen. The results suggested that element types with similar formulation yield matching results independent of the finite element software used. For comparison, m ixed-mode strain energy release rates were also calculated within ABAQUS#/Standard using the VCCT for ABAQUS# add on. For all specimens mod eled, mixed-mode strain energy release rates obtained from ABAQUS# finite element results using post-processing were almost identical to re sults calculated using the VCCT for ABAQUS# add on.

  10. Interdisciplinary Team-Teaching Experience for a Computer and Nuclear Energy Course for Electrical and Computer Engineering Students

    ERIC Educational Resources Information Center

    Kim, Charles; Jackson, Deborah; Keiller, Peter

    2016-01-01

    A new, interdisciplinary, team-taught course has been designed to educate students in Electrical and Computer Engineering (ECE) so that they can respond to global and urgent issues concerning computer control systems in nuclear power plants. This paper discusses our experience and assessment of the interdisciplinary computer and nuclear energy…

  11. Geology and mineral and energy resources, Roswell Resource Area, New Mexico; an interactive computer presentation

    USGS Publications Warehouse

    Tidball, Ronald R.; Bartsch-Winkler, S. B.

    1995-01-01

    This Compact Disc-Read Only Memory (CD-ROM) contains a program illustrating the geology and mineral and energy resources of the Roswell Resource Area, an administrative unit of the U.S. Bureau of Land Management in east-central New Mexico. The program enables the user to access information on the geology, geochemistry, geophysics, mining history, metallic and industrial mineral commodities, hydrocarbons, and assessments of the area. The program was created with the display software, SuperCard, version 1.5, by Aldus. The program will run only on a Macintosh personal computer. This CD-ROM was produced in accordance with Macintosh HFS standards. The program was developed on a Macintosh II-series computer with system 7.0.1. The program is a compiled, executable form that is nonproprietary and does not require the presence of the SuperCard software.

  12. Expedited Holonomic Quantum Computation via Net Zero-Energy-Cost Control in Decoherence-Free Subspace

    PubMed Central

    Pyshkin, P. V.; Luo, Da-Wei; Jing, Jun; You, J. Q.; Wu, Lian-Ao

    2016-01-01

    Holonomic quantum computation (HQC) may not show its full potential in quantum speedup due to the prerequisite of a long coherent runtime imposed by the adiabatic condition. Here we show that the conventional HQC can be dramatically accelerated by using external control fields, of which the effectiveness is exclusively determined by the integral of the control fields in the time domain. This control scheme can be realized with net zero energy cost and it is fault-tolerant against fluctuation and noise, significantly relaxing the experimental constraints. We demonstrate how to realize the scheme via decoherence-free subspaces. In this way we unify quantum robustness merits of this fault-tolerant control scheme, the conventional HQC and decoherence-free subspace, and propose an expedited holonomic quantum computation protocol. PMID:27886234

  13. Measured energy savings and performance of power-managed personal computers and monitors

    SciTech Connect

    Nordman, B.; Piette, M.A.; Kinney, K.

    1996-08-01

    Personal computers and monitors are estimated to use 14 billion kWh/year of electricity, with power management potentially saving $600 million/year by the year 2000. The effort to capture these savings is lead by the US Environmental Protection Agency`s Energy Star program, which specifies a 30W maximum demand for the computer and for the monitor when in a {open_quote}sleep{close_quote} or idle mode. In this paper the authors discuss measured energy use and estimated savings for power-managed (Energy Star compliant) PCs and monitors. They collected electricity use measurements of six power-managed PCs and monitors in their office and five from two other research projects. The devices are diverse in machine type, use patterns, and context. The analysis method estimates the time spent in each system operating mode (off, low-, and full-power) and combines these with real power measurements to derive hours of use per mode, energy use, and energy savings. Three schedules are explored in the {open_quotes}As-operated,{close_quotes} {open_quotes}Standardized,{close_quotes} and `Maximum` savings estimates. Energy savings are established by comparing the measurements to a baseline with power management disabled. As-operated energy savings for the eleven PCs and monitors ranged from zero to 75 kWh/year. Under the standard operating schedule (on 20% of nights and weekends), the savings are about 200 kWh/year. An audit of power management features and configurations for several dozen Energy Star machines found only 11% of CPU`s fully enabled and about two thirds of monitors were successfully power managed. The highest priority for greater power management savings is to enable monitors, as opposed to CPU`s, since they are generally easier to configure, less likely to interfere with system operation, and have greater savings. The difficulties in properly configuring PCs and monitors is the largest current barrier to achieving the savings potential from power management.

  14. Measuring and tuning energy efficiency on large scale high performance computing platforms.

    SciTech Connect

    Laros, James H., III

    2011-08-01

    Recognition of the importance of power in the field of High Performance Computing, whether it be as an obstacle, expense or design consideration, has never been greater and more pervasive. While research has been conducted on many related aspects, there is a stark absence of work focused on large scale High Performance Computing. Part of the reason is the lack of measurement capability currently available on small or large platforms. Typically, research is conducted using coarse methods of measurement such as inserting a power meter between the power source and the platform, or fine grained measurements using custom instrumented boards (with obvious limitations in scale). To collect the measurements necessary to analyze real scientific computing applications at large scale, an in-situ measurement capability must exist on a large scale capability class platform. In response to this challenge, we exploit the unique power measurement capabilities of the Cray XT architecture to gain an understanding of power use and the effects of tuning. We apply these capabilities at the operating system level by deterministically halting cores when idle. At the application level, we gain an understanding of the power requirements of a range of important DOE/NNSA production scientific computing applications running at large scale (thousands of nodes), while simultaneously collecting current and voltage measurements on the hosting nodes. We examine the effects of both CPU and network bandwidth tuning and demonstrate energy savings opportunities of up to 39% with little or no impact on run-time performance. Capturing scale effects in our experimental results was key. Our results provide strong evidence that next generation large-scale platforms should not only approach CPU frequency scaling differently, but could also benefit from the capability to tune other platform components, such as the network, to achieve energy efficient performance.

  15. A Monte Carlo simulation study of the effect of energy windows in computed tomography images based on an energy-resolved photon counting detector.

    PubMed

    Lee, Seung-Wan; Choi, Yu-Na; Cho, Hyo-Min; Lee, Young-Jin; Ryu, Hyun-Ju; Kim, Hee-Joung

    2012-08-07

    The energy-resolved photon counting detector provides the spectral information that can be used to generate images. The novel imaging methods, including the K-edge imaging, projection-based energy weighting imaging and image-based energy weighting imaging, are based on the energy-resolved photon counting detector and can be realized by using various energy windows or energy bins. The location and width of the energy windows or energy bins are important because these techniques generate an image using the spectral information defined by the energy windows or energy bins. In this study, the reconstructed images acquired with K-edge imaging, projection-based energy weighting imaging and image-based energy weighting imaging were simulated using the Monte Carlo simulation. The effect of energy windows or energy bins was investigated with respect to the contrast, coefficient-of-variation (COV) and contrast-to-noise ratio (CNR). The three images were compared with respect to the CNR. We modeled the x-ray computed tomography system based on the CdTe energy-resolved photon counting detector and polymethylmethacrylate phantom, which have iodine, gadolinium and blood. To acquire K-edge images, the lower energy thresholds were fixed at K-edge absorption energy of iodine and gadolinium and the energy window widths were increased from 1 to 25 bins. The energy weighting factors optimized for iodine, gadolinium and blood were calculated from 5, 10, 15, 19 and 33 energy bins. We assigned the calculated energy weighting factors to the images acquired at each energy bin. In K-edge images, the contrast and COV decreased, when the energy window width was increased. The CNR increased as a function of the energy window width and decreased above the specific energy window width. When the number of energy bins was increased from 5 to 15, the contrast increased in the projection-based energy weighting images. There is a little difference in the contrast, when the number of energy bin is

  16. Low-energy light bulbs, computers, tablets and the blue light hazard.

    PubMed

    O'Hagan, J B; Khazova, M; Price, L L A

    2016-02-01

    The introduction of low energy lighting and the widespread use of computer and mobile technologies have changed the exposure of human eyes to light. Occasional claims that the light sources with emissions containing blue light may cause eye damage raise concerns in the media. The aim of the study was to determine if it was appropriate to issue advice on the public health concerns. A number of sources were assessed and the exposure conditions were compared with international exposure limits, and the exposure likely to be received from staring at a blue sky. None of the sources assessed approached the exposure limits, even for extended viewing times.

  17. A computer model of the energy-current loss instabilities in a recirculating accelerator system

    NASA Astrophysics Data System (ADS)

    Edighoffer, J. A.; Kim, K.-J.

    1995-04-01

    The computer program called ESRA (energy stability in a recirculating accelerator FELs) has been written to model bunches of particles in longitudinal phase space traversing a recirculating accelerator and the associated rf changes and aperture current losses. This code addresses stability issues and determines the transport, noise, feedback and other parameters for which these FEL systems are stable or unstable. A representative system is modeled, the Novosibirisk high power FEL race-track microtron for photochemical research. The system is stable with prudent choice of parameters.

  18. Low-energy light bulbs, computers, tablets and the blue light hazard

    PubMed Central

    O'Hagan, J B; Khazova, M; Price, L L A

    2016-01-01

    The introduction of low energy lighting and the widespread use of computer and mobile technologies have changed the exposure of human eyes to light. Occasional claims that the light sources with emissions containing blue light may cause eye damage raise concerns in the media. The aim of the study was to determine if it was appropriate to issue advice on the public health concerns. A number of sources were assessed and the exposure conditions were compared with international exposure limits, and the exposure likely to be received from staring at a blue sky. None of the sources assessed approached the exposure limits, even for extended viewing times. PMID:26768920

  19. Using an iterative eigensolver to compute vibrational energies with phase-spaced localized basis functions

    SciTech Connect

    Brown, James Carrington, Tucker

    2015-07-28

    Although phase-space localized Gaussians are themselves poor basis functions, they can be used to effectively contract a discrete variable representation basis [A. Shimshovitz and D. J. Tannor, Phys. Rev. Lett. 109, 070402 (2012)]. This works despite the fact that elements of the Hamiltonian and overlap matrices labelled by discarded Gaussians are not small. By formulating the matrix problem as a regular (i.e., not a generalized) matrix eigenvalue problem, we show that it is possible to use an iterative eigensolver to compute vibrational energy levels in the Gaussian basis.

  20. Lookup tables to compute high energy cosmic ray induced atmospheric ionization and changes in atmospheric chemistry

    SciTech Connect

    Atri, Dimitra; Melott, Adrian L.; Thomas, Brian C. E-mail: melott@ku.edu

    2010-05-01

    A variety of events such as gamma-ray bursts and supernovae may expose the Earth to an increased flux of high-energy cosmic rays, with potentially important effects on the biosphere. Existing atmospheric chemistry software does not have the capability of incorporating the effects of substantial cosmic ray flux above 10 GeV. An atmospheric code, the NASA-Goddard Space Flight Center two-dimensional (latitude, altitude) time-dependent atmospheric model (NGSFC), is used to study atmospheric chemistry changes. Using CORSIKA, we have created tables that can be used to compute high energy cosmic ray (10 GeV–1 PeV) induced atmospheric ionization and also, with the use of the NGSFC code, can be used to simulate the resulting atmospheric chemistry changes. We discuss the tables, their uses, weaknesses, and strengths.

  1. The potential of computed crystal energy landscapes to aid solid-form development.

    PubMed

    Price, Sarah L; Reutzel-Edens, Susan M

    2016-06-01

    Solid-form screening to identify all solid forms of an active pharmaceutical ingredient (API) has become increasingly important in ensuring the quality by design of pharmaceutical products and their manufacturing processes. However, despite considerable enlargement of the range of techniques that have been shown capable of producing novel solid forms, it is possible that practically important forms might not be found in the short timescales currently allowed for solid-form screening. Here, we report on the state-of-the-art use of computed crystal energy landscapes to complement pharmaceutical solid-form screening. We illustrate how crystal energy landscapes can help establish molecular-level understanding of the crystallization behavior of APIs and enhance the ability of solid-form screening to facilitate pharmaceutical development.

  2. Dual-energy computed tomography for detection of coronary artery disease

    PubMed Central

    Danad, Ibrahim; Ó Hartaigh, Bríain; Min, James K.

    2016-01-01

    Recent technological advances in computed tomography (CT) technology have fulfilled the prerequisites for the cardiac application of dual-energy CT (DECT) imaging. By exploiting the unique characteristics of materials when exposed to two different x-ray energies, DECT holds great promise for the diagnosis and management of coronary artery disease. It allows for the assessment of myocardial perfusion to discern the hemodynamic significance of coronary disease and possesses high accuracy for the detection and characterization of coronary plaques, while facilitating reductions in radiation dose. As such, DECT enabled cardiac CT to advance beyond the mere detection of coronary stenosis expanding its role in the evaluation and management of coronary atherosclerosis. PMID:26549789

  3. Real Gas Computation Using an Energy Relaxation Method and High-Order WENO Schemes

    NASA Technical Reports Server (NTRS)

    Montarnal, Philippe; Shu, Chi-Wang

    1998-01-01

    In this paper, we use a recently developed energy relaxation theory by Coquel and Perthame and high order weighted essentially non-oscillatory (WENO) schemes to simulate the Euler equations of real gas. The main idea is an energy decomposition into two parts: one part is associated with a simpler pressure law and the other part (the nonlinear deviation) is convected with the flow. A relaxation process is performed for each time step to ensure that the original pressure law is satisfied. The necessary characteristic decomposition for the high order WENO schemes is performed on the characteristic fields based on the first part. The algorithm only calls for the original pressure law once per grid point per time step, without the need to compute its derivatives or any Riemann solvers. Both one and two dimensional numerical examples are shown to illustrate the effectiveness of this approach.

  4. A Cross-Cultural Study of the Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Middle School Students' Science Knowledge and Argumentation Skills

    ERIC Educational Resources Information Center

    Hsu, P.-S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2016-01-01

    The purpose of this mixed-methods study was to explore how seventh graders in a suburban school in the United States and sixth graders in an urban school in Taiwan developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application (GOCAA). A total of 42…

  5. Career Oriented Mathematics, Teacher's Manual. [Includes Mastering Computational Skill: A Use-Based Program; Owning an Automobile and Driving as a Career; Retail Sales; Measurement; and Area-Perimeter.

    ERIC Educational Resources Information Center

    Mahaffey, Michael L.; McKillip, William D.

    This manual is designed for teachers using the Career Oriented Mathematics units on owning an automobile and driving as a career, retail sales, measurement, and area-perimeter. The volume begins with a discussion of the philosophy and scheduling of the program which is designed to improve students' attitudes and ability in computation by…

  6. Massively parallel computation of absolute binding free energy with well-equilibrated states

    NASA Astrophysics Data System (ADS)

    Fujitani, Hideaki; Tanida, Yoshiaki; Matsuura, Azuma

    2009-02-01

    A force field formulator for organic molecules (FF-FOM) was developed to assign bond, angle, and dihedral parameters to arbitrary organic molecules in a unified manner including proteins and nucleic acids. With the unified force field parametrization we performed massively parallel computations of absolute binding free energies for pharmaceutical target proteins and ligands. Compared with the previous calculation with the ff99 force field in the Amber simulation package (Amber99) and the ligand charges produced by the Austin Model 1 bond charge correction (AM1-BCC), the unified parametrization gave better absolute binding energies for the FK506 binding protein (FKBP) and ligand system. Our method is based on extensive work measurement between thermodynamic states to calculate the free energy difference and it is also the same as the traditional free energy perturbation. There are important requirements for accurate calculations. The first is a well-equilibrated bound structure including the conformational change of the protein induced by the binding of the ligand. The second requirement is the convergence of the work distribution with a sufficient number of trajectories and dense spacing of the coupling constant between the ligand and the rest of the system. Finally, the most important requirement is the force field parametrization.

  7. Computed tomography dosimetry with high-resolution detectors commonly used in radiotherapy - an energy dependence study.

    PubMed

    Liebmann, Mario; Poppe, Bjoern; von Boetticher, Heiner

    2015-09-08

    New methods of dosimetry in computed tomography (CT) X-ray fields require the use of high-resolution detectors instead of pencil-type ionization chambers typically used for CT dose index (CTDI) measurements. This paper presents a study on the suitability of a wide range of ionization chambers, diodes, and a two-dimensional detector array, used primarily in radiation therapy, for CT and cone-beam CT dosimetry. Specifically, the energy dependence of these detectors from 50 kVp up to 125 kVp is reported. All measurements were performed in reference to a calibrated diode for use in this energy region. The radiation quality correction factors provided by the manufacturer were used, depending on the measured half-value layer (HVL) for the particular X-ray beam. Our study demonstrated the general usability of thimble ionization chambers. These thimble ionization chambers showed a maximum variation in energy response of 5%. Ionization chambers with even smaller sensitive volume, and which exhibit similar variation in energy dependence, can be used if higher spatial resolution is required. Furthermore, the investigated detectors are better suited for dosimetry at CT and CBCT units than conventional large volume or flat detectors, due to their rotational symmetry. Nevertheless, a flat detector can be used for certain measurement tasks, such as the acquisition of percent depth-dose curves or beam profiles for nonrotating beams, which are important for beam characterization.

  8. Thermodynamic analysis of five compressed-air energy-storage cycles. [Using CAESCAP computer code

    SciTech Connect

    Fort, J. A.

    1983-03-01

    One important aspect of the Compressed-Air Energy-Storage (CAES) Program is the evaluation of alternative CAES plant designs. The thermodynamic performance of the various configurations is particularly critical to the successful demonstration of CAES as an economically feasible energy-storage option. A computer code, the Compressed-Air Energy-Storage Cycle-Analysis Program (CAESCAP), was developed in 1982 at the Pacific Northwest Laboratory. This code was designed specifically to calculate overall thermodynamic performance of proposed CAES-system configurations. The results of applying this code to the analysis of five CAES plant designs are presented in this report. The designs analyzed were: conventional CAES; adiabatic CAES; hybrid CAES; pressurized fluidized-bed CAES; and direct coupled steam-CAES. Inputs to the code were based on published reports describing each plant cycle. For each cycle analyzed, CAESCAP calculated the thermodynamic station conditions and individual-component efficiencies, as well as overall cycle-performance-parameter values. These data were then used to diagram the availability and energy flow for each of the five cycles. The resulting diagrams graphically illustrate the overall thermodynamic performance inherent in each plant configuration, and enable a more accurate and complete understanding of each design.

  9. Computing dispersive, polarizable, and electrostatic shifts of excitation energy in supramolecular systems: PTCDI crystal.

    PubMed

    Megow, Jörg

    2016-09-07

    The gas-to-crystal-shift denotes the shift of electronic excitation energies, i.e., the difference between ground and excited state energies, for a molecule transferred from the gas to the bulk phase. The contributions to the gas-to-crystal-shift comprise electrostatic as well as inductive polarization and dispersive energy shifts of the molecular excitation energies due to interaction with environmental molecules. For the example of 3,4,9,10-perylene-tetracarboxylic-diimide (PTCDI) bulk, the contributions to the gas-to-crystal shift are investigated. In the present work, electrostatic interaction is calculated via Coulomb interaction of partial charges while inductive and dispersive interactions are obtained using respective sum over states expressions. The coupling of higher transition densities for the first 4500 excited states of PTCDI was computed using transition partial charges based on an atomistic model of PTCDI bulk obtained from molecular dynamics simulations. As a result it is concluded that for the investigated model system of a PTCDI crystal, the gas to crystal shift is dominated by dispersive interaction.

  10. A survey and taxonomy on energy efficient resource allocation techniques for cloud computing systems

    SciTech Connect

    Hameed, Abdul; Khoshkbarforoushha, Alireza; Ranjan, Rajiv; Jayaraman, Prem Prakash; Kolodziej, Joanna; Balaji, Pavan; Zeadally, Sherali; Malluhi, Qutaibah Marwan; Tziritas, Nikos; Vishnu, Abhinav; Khan, Samee U.; Zomaya, Albert

    2014-06-06

    In a cloud computing paradigm, energy efficient allocation of different virtualized ICT resources (servers, storage disks, and networks, and the like) is a complex problem due to the presence of heterogeneous application (e.g., content delivery networks, MapReduce, web applications, and the like) workloads having contentious allocation requirements in terms of ICT resource capacities (e.g., network bandwidth, processing speed, response time, etc.). Several recent papers have tried to address the issue of improving energy efficiency in allocating cloud resources to applications with varying degree of success. However, to the best of our knowledge there is no published literature on this subject that clearly articulates the research problem and provides research taxonomy for succinct classification of existing techniques. Hence, the main aim of this paper is to identify open challenges associated with energy efficient resource allocation. In this regard, the study, first, outlines the problem and existing hardware and software-based techniques available for this purpose. Furthermore, available techniques already presented in the literature are summarized based on the energy-efficient research dimension taxonomy. The advantages and disadvantages of the existing techniques are comprehensively analyzed against the proposed research dimension taxonomy namely: resource adaption policy, objective function, allocation method, allocation operation, and interoperability.

  11. Computational Study of Environmental Effects on Torsional Free Energy Surface of N-Acetyl-N'-methyl-L-alanylamide Dipeptide

    ERIC Educational Resources Information Center

    Carlotto, Silvia; Zerbetto, Mirco

    2014-01-01

    We propose an articulated computational experiment in which both quantum mechanics (QM) and molecular mechanics (MM) methods are employed to investigate environment effects on the free energy surface for the backbone dihedral angles rotation of the small dipeptide N-Acetyl-N'-methyl-L-alanylamide. This computation exercise is appropriate for an…

  12. Computer simulation to predict energy use, greenhouse gas emissions and costs for production of fluid milk using alternative processing methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Computer simulation is a useful tool for benchmarking the electrical and fuel energy consumption and water use in a fluid milk plant. In this study, a computer simulation model of the fluid milk process based on high temperature short time (HTST) pasteurization was extended to include models for pr...

  13. User's manual: Computer-aided design programs for inductor-energy-storage dc-to-dc electronic power converters

    NASA Technical Reports Server (NTRS)

    Huffman, S.

    1977-01-01

    Detailed instructions on the use of two computer-aided-design programs for designing the energy storage inductor for single winding and two winding dc to dc converters are provided. Step by step procedures are given to illustrate the formatting of user input data. The procedures are illustrated by eight sample design problems which include the user input and the computer program output.

  14. A computational analysis of low-energy electron scattering from gaseous cyclopropane

    NASA Astrophysics Data System (ADS)

    Curík, R.; Gianturco, F. A.

    2002-02-01

    Absolute elastic cross sections, integral and differential, are computed for electron-cyclopropane collisions at energies from 1.0 up to 15.0 eV, spanning the region where possible shape resonance structures were detected by earlier experiments and calculations. The present results confirm the above findings and locate a resonance of A2' symmetry around 6.0 eV and a broader, weaker resonance of A2'' symmetry around 8 eV. The calculations are further shown to be in good agreement with the existing measurements of the angular distributions of the scattered electrons at energies from 2.0 up to 10.0 eV. The presently computed cross sections also agree with earlier R-matrix calculations (Beyer T, Nestmann B M, Sarpal B K and Peyerimhoff S D 1997 J. Phys. B: At. Mol. Opt. Phys. 30 3431) and with the available integral cross section measurements. A model local exchange potential of very simple usage is shown to provide quite good accord with the exact calculations at the static-exchange level.

  15. Development of a Learning-Oriented Computer Assisted Instruction Designed to Improve Skills in the Clinical Assessment of the Nutritional Status: A Pilot Evaluation

    PubMed Central

    García de Diego, Laura; Cuervo, Marta; Martínez, J. Alfredo

    2015-01-01

    Computer assisted instruction (CAI) is an effective tool for evaluating and training students and professionals. In this article we will present a learning-oriented CAI, which has been developed for students and health professionals to acquire and retain new knowledge through the practice. A two-phase pilot evaluation was conducted, involving 8 nutrition experts and 30 postgraduate students, respectively. In each training session, the software developed guides users in the integral evaluation of a patient’s nutritional status and helps them to implement actions. The program includes into the format clinical tools, which can be used to recognize possible patient’s needs, to improve the clinical reasoning and to develop professional skills. Among them are assessment questionnaires and evaluation criteria, cardiovascular risk charts, clinical guidelines and photographs of various diseases. This CAI is a complete software package easy to use and versatile, aimed at clinical specialists, medical staff, scientists, educators and clinical students, which can be used as a learning tool. This application constitutes an advanced method for students and health professionals to accomplish nutritional assessments combining theoretical and empirical issues, which can be implemented in their academic curriculum. PMID:25978456

  16. Quantum computing applied to calculations of molecular energies: CH2 benchmark.

    PubMed

    Veis, Libor; Pittner, Jiří

    2010-11-21

    Quantum computers are appealing for their ability to solve some tasks much faster than their classical counterparts. It was shown in [Aspuru-Guzik et al., Science 309, 1704 (2005)] that they, if available, would be able to perform the full configuration interaction (FCI) energy calculations with a polynomial scaling. This is in contrast to conventional computers where FCI scales exponentially. We have developed a code for simulation of quantum computers and implemented our version of the quantum FCI algorithm. We provide a detailed description of this algorithm and the results of the assessment of its performance on the four lowest lying electronic states of CH(2) molecule. This molecule was chosen as a benchmark, since its two lowest lying (1)A(1) states exhibit a multireference character at the equilibrium geometry. It has been shown that with a suitably chosen initial state of the quantum register, one is able to achieve the probability amplification regime of the iterative phase estimation algorithm even in this case.

  17. Software Aspects of IEEE Floating-Point Computations for Numerical Applications in High Energy Physics

    ScienceCinema

    None

    2016-07-12

    Floating-point computations are at the heart of much of the computing done in high energy physics. The correctness, speed and accuracy of these computations are of paramount importance. The lack of any of these characteristics can mean the difference between new, exciting physics and an embarrassing correction. This talk will examine practical aspects of IEEE 754-2008 floating-point arithmetic as encountered in HEP applications. After describing the basic features of IEEE floating-point arithmetic, the presentation will cover: common hardware implementations (SSE, x87) techniques for improving the accuracy of summation, multiplication and data interchange compiler options for gcc and icc affecting floating-point operations hazards to be avoided About the speaker Jeffrey M Arnold is a Senior Software Engineer in the Intel Compiler and Languages group at Intel Corporation. He has been part of the Digital->Compaq->Intel compiler organization for nearly 20 years; part of that time, he worked on both low- and high-level math libraries. Prior to that, he was in the VMS Engineering organization at Digital Equipment Corporation. In the late 1980s, Jeff spent 2½ years at CERN as part of the CERN/Digital Joint Project. In 2008, he returned to CERN to spent 10 weeks working with CERN/openlab. Since that time, he has returned to CERN multiple times to teach at openlab workshops and consult with various LHC experiments. Jeff received his Ph.D. in physics from Case Western Reserve University.

  18. A Computational Approach for Model Update of an LS-DYNA Energy Absorbing Cell

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G.; Jackson, Karen E.; Kellas, Sotiris

    2008-01-01

    NASA and its contractors are working on structural concepts for absorbing impact energy of aerospace vehicles. Recently, concepts in the form of multi-cell honeycomb-like structures designed to crush under load have been investigated for both space and aeronautics applications. Efforts to understand these concepts are progressing from tests of individual cells to tests of systems with hundreds of cells. Because of fabrication irregularities, geometry irregularities, and material properties uncertainties, the problem of reconciling analytical models, in particular LS-DYNA models, with experimental data is a challenge. A first look at the correlation results between single cell load/deflection data with LS-DYNA predictions showed problems which prompted additional work in this area. This paper describes a computational approach that uses analysis of variance, deterministic sampling techniques, response surface modeling, and genetic optimization to reconcile test with analysis results. Analysis of variance provides a screening technique for selection of critical parameters used when reconciling test with analysis. In this study, complete ignorance of the parameter distribution is assumed and, therefore, the value of any parameter within the range that is computed using the optimization procedure is considered to be equally likely. Mean values from tests are matched against LS-DYNA solutions by minimizing the square error using a genetic optimization. The paper presents the computational methodology along with results obtained using this approach.

  19. Computing the energy of a water molecule using multideterminants: A simple, efficient algorithm

    SciTech Connect

    Clark, Bryan K.; Morales, Miguel A; Mcminis, Jeremy; Kim, Jeongnim; Scuseria, Gustavo E

    2011-01-01

    Quantum Monte Carlo (QMC) methods such as variational Monte Carlo and fixed node diffusion Monte Carlo depend heavily on the quality of the trial wave function. Although Slater-Jastrow wave functions are the most commonly used variational ansatz in electronic structure, more sophisticated wave functions are critical to ascertaining new physics. One such wave function is the multi-Slater- Jastrow wave function which consists of a Jastrow function multiplied by the sum of Slater deter- minants. In this paper we describe a method for working with these wave functions in QMC codes that is easy to implement, efficient both in computational speed as well as memory, and easily par- allelized. The computational cost scales quadratically with particle number making this scaling no worse than the single determinant case and linear with the total number of excitations. Addition- ally, we implement this method and use it to compute the ground state energy of a water molecule. 2011 American Institute of Physics. [doi:10.1063/1.3665391

  20. Energy in Perspective: An Orientation Conference for Educators. Proceedings of a Conference (Tempe, Arizona, June 7-11, 1976).

    ERIC Educational Resources Information Center

    McKlveen, John W., Ed.

    The conference goal was to provide educators with knowledge and motivation about energy in order to establish an awareness of it in their classrooms. Speakers were from universities, research laboratories, utilities, government agencies, and private businesses. Coal, gas and oil, geothermal and solar sources of energy in Arizona were each…

  1. PREFACE: 21st International Conference on Computing in High Energy and Nuclear Physics (CHEP2015)

    NASA Astrophysics Data System (ADS)

    Sakamoto, H.; Bonacorsi, D.; Ueda, I.; Lyon, A.

    2015-12-01

    The International Conference on Computing in High Energy and Nuclear Physics (CHEP) is a major series of international conferences intended to attract physicists and computing professionals to discuss on recent developments and trends in software and computing for their research communities. Experts from the high energy and nuclear physics, computer science, and information technology communities attend CHEP events. This conference series provides an international forum to exchange experiences and the needs of a wide community, and to present and discuss recent, ongoing, and future activities. At the beginning of the successful series of CHEP conferences in 1985, the latest developments in embedded systems, networking, vector and parallel processing were presented in Amsterdam. The software and computing ecosystem massively evolved since then, and along this path each CHEP event has marked a step further. A vibrant community of experts on a wide range of different high-energy and nuclear physics experiments, as well as technology explorer and industry contacts, attend and discuss the present and future challenges, and shape the future of an entire community. In such a rapidly evolving area, aiming to capture the state-of-the-art on software and computing through a collection of proceedings papers on a journal is a big challenge. Due to the large attendance, the final papers appear on the journal a few months after the conference is over. Additionally, the contributions often report about studies at very heterogeneous statuses, namely studies that are completed, or are just started, or yet to be done. It is not uncommon that by the time a specific paper appears on the journal some of the work is over a year old, or the investigation actually happened in different directions and with different methodologies than originally presented at the conference just a few months before. And by the time the proceedings appear in journal form, new ideas and explorations have

  2. PREFACE: International Conference on Computing in High Energy and Nuclear Physics (CHEP'09)

    NASA Astrophysics Data System (ADS)

    Gruntorad, Jan; Lokajicek, Milos

    2010-11-01

    The 17th International Conference on Computing in High Energy and Nuclear Physics (CHEP) was held on 21-27 March 2009 in Prague, Czech Republic. CHEP is a major series of international conferences for physicists and computing professionals from the worldwide High Energy and Nuclear Physics community, Computer Science, and Information Technology. The CHEP conference provides an international forum to exchange information on computing experience and needs for the community, and to review recent, ongoing and future activities. Recent conferences were held in Victoria, Canada 2007, Mumbai, India in 2006, Interlaken, Switzerland in 2004, San Diego, USA in 2003, Beijing, China in 2001, Padua, Italy in 2000. The CHEP'09 conference had 600 attendees with a program that included plenary sessions of invited oral presentations, a number of parallel sessions comprising 200 oral and 300 poster presentations, and an industrial exhibition. We thanks all the presenters, for the excellent scientific content of their contributions to the conference. Conference tracks covered topics on Online Computing, Event Processing, Software Components, Tools and Databases, Hardware and Computing Fabrics, Grid Middleware and Networking Technologies, Distributed Processing and Analysis and Collaborative Tools. The conference included excursions to Prague and other Czech cities and castles and a banquet held at the Zofin palace in Prague. The next CHEP conference will be held in Taipei, Taiwan on 18-22 October 2010. We would like thank the Ministry of Education Youth and Sports of the Czech Republic and the EU ACEOLE project for the conference support, further to commercial sponsors, the International Advisory Committee, the Local Organizing Committee members representing the five collaborating Czech institutions Jan Gruntorad (co-chair), CESNET, z.s.p.o., Prague Andrej Kugler, Nuclear Physics Institute AS CR v.v.i., Rez Rupert Leitner, Charles University in Prague, Faculty of Mathematics and

  3. Intermolecular energy-band dispersion in oriented thin films of bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole) by angle-resolved photoemission

    NASA Astrophysics Data System (ADS)

    Hasegawa, Shinji; Mori, Takehiko; Imaeda, Kenichi; Tanaka, Shoji; Yamashita, Yoshiro; Inokuchi, Hiroo; Fujimoto, Hitoshi; Seki, Kazuhiko; Ueno, Nobuo

    1994-05-01

    Angle-resolved ultraviolet photoemission spectra using synchrotron radiation were measured for oriented thin films of bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole) (BTQBT) on graphite. From the photon energy dependence of normal emission spectra, the energy-band dispersion of π-bands were observed for the highest (HOMO) and next highest (NHOMO) bands. This is the first observation of intermolecular dispersion in a single-component organic molecular crystal. The results demonstrate that the BTQBT molecules have a strong intermolecular interaction, which can be derived from the introduction of a covalent interaction between sulfur atoms in addition to the usual intermolecular interaction by van der Waals forces.

  4. Free energy of contact formation in proteins: Efficient computation in the elastic network approximation

    NASA Astrophysics Data System (ADS)

    Hamacher, Kay

    2011-07-01

    Biomolecular simulations have become a major tool in understanding biomolecules and their complexes. However, one can typically only investigate a few mutants or scenarios due to the severe computational demands of such simulations, leading to a great interest in method development to overcome this restriction. One way to achieve this is to reduce the complexity of the systems by an approximation of the forces acting upon the constituents of the molecule. The harmonic approximation used in elastic network models simplifies the physical complexity to the most reduced dynamics of these molecular systems. The reduced polymer modeled this way is typically comprised of mass points representing coarse-grained versions of, e.g., amino acids. In this work, we show how the computation of free energy contributions of contacts between two residues within the molecule can be reduced to a simple lookup operation in a precomputable matrix. Being able to compute such contributions is of great importance: protein design or molecular evolution changes introduce perturbations to these pair interactions, so we need to understand their impact. Perturbation to the interactions occurs due to randomized and fixated changes (in molecular evolution) or designed modifications of the protein structures (in bioengineering). These perturbations are modifications in the topology and the strength of the interactions modeled by the elastic network models. We apply the new algorithm to (1) the bovine trypsin inhibitor, a well-known enzyme in biomedicine, and show the connection to folding properties and the hydrophobic collapse hypothesis and (2) the serine proteinase inhibitor CI-2 and show the correlation to Φ values to characterize folding importance. Furthermore, we discuss the computational complexity and show empirical results for the average case, sampled over a library of 77 structurally diverse proteins. We found a relative speedup of up to 10 000-fold for large proteins with respect to

  5. Comparison of Explicitly Correlated Methods for Computing High-Accuracy Benchmark Energies for Noncovalent Interactions.

    PubMed

    Sirianni, Dominic A; Burns, Lori A; Sherrill, C David

    2017-01-10

    The reliability of explicitly correlated methods for providing benchmark-quality noncovalent interaction energies was tested at various levels of theory and compared to estimates of the complete basis set (CBS) limit. For all systems of the A24 test set, computations were performed using both aug-cc-pVXZ (aXZ; X = D, T, Q, 5) basis sets and specialized cc-pVXZ-F12 (XZ-F12; X = D, T, Q, 5) basis sets paired with explicitly correlated coupled cluster singles and doubles [CCSD-F12n (n = a, b, c)] with triple excitations treated by the canonical perturbative method and scaled to compensate for their lack of explicit correlation [(T**)]. Results show that aXZ basis sets produce smaller errors versus the CBS limit than XZ-F12 basis sets. The F12b ansatz results in the lowest average errors for aTZ and larger basis sets, while F12a is best for double-ζ basis sets. When using aXZ basis sets (X ≥ 3), convergence is achieved from above for F12b and F12c ansatzë and from below for F12a. The CCSD(T**)-F12b/aXZ approach converges quicker with respect to basis than any other combination, although the performance of CCSD(T**)-F12c/aXZ is very similar. Both CCSD(T**)-F12b/aTZ and focal point schemes employing density-fitted, frozen natural orbital [DF-FNO] CCSD(T)/aTZ exhibit similar accuracy and computational cost, and both are much more computationally efficient than large-basis conventional CCSD(T) computations of similar accuracy.

  6. Refining the Resolution of Future Energy-Water Projection through High Performance Computing (Invited)

    NASA Astrophysics Data System (ADS)

    Kao, S.; Naz, B.; Ashfaq, M.; Mei, R.

    2013-12-01

    With the advance of high performance computing and more abundant historic observation, the resolution and accuracy of hydro-climate projection can now be efficiently improved. Based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections, a series of hydro-climatic models and datasets, including Regional Climate Models, Variable Infiltration Capacity (VIC) hydrologic model, historic runoff-generation relationships and a national hydropower dataset, are jointly utilized to project the future hydropower production at various U.S. regions. To refine spatial resolution and reduce modeling uncertainty, particular efforts were focused on calibrating the VIC hydrologic model at 4-Km spatial resolution. Driven by 1980-2008 DAYMET meteorological observation (biased adjusted by PRISM dataset), the simulated VIC total runoff (baseflow + surface runoff) was calibrated to U.S. Geological Survey WaterWatch monthly runoff observation at 2107 hydrologic Subbasins (HUC8s) in the Conterminous U.S. Each HUC8 was subdivided into 16, 32, or 48 computation units for parallel computing. The simulation was conducted using Oak Ridge National Laboratory's Titan supercomputer, a Cray XK7 system with 18,688 computational nodes, each equipped with four quad-core CPUs and two GPU cards. To date, ~2.5 million CPU-hours (i.e., the number of CPUs multiplied by the average hours used by each CPU) have been used to improve the modeling performance for most of the HUC8s. Using the calibrated model, hydro-climate projections will be produced for various dynamically-downscaled CMIP5 simulations, and will be utilized to project seasonal and monthly hydropower production for various U.S. regions. It is expected that with reduced modeling uncertainty, the regional water budget can be more accurately estimated and it will eventually lead to better simulation and allocation of limited water resources under climate, energy, and water nexus.

  7. Complementary contrast media for metal artifact reduction in dual-energy computed tomography

    PubMed Central

    Lambert, Jack W.; Edic, Peter M.; FitzGerald, Paul F.; Torres, Andrew S.; Yeh, Benjamin M.

    2015-01-01

    Abstract. Metal artifacts have been a problem associated with computed tomography (CT) since its introduction. Recent techniques to mitigate this problem have included utilization of high-energy (keV) virtual monochromatic spectral (VMS) images, produced via dual-energy CT (DECT). A problem with these high-keV images is that contrast enhancement provided by all commercially available contrast media is severely reduced. Contrast agents based on higher atomic number elements can maintain contrast at the higher energy levels where artifacts are reduced. This study evaluated three such candidate elements: bismuth, tantalum, and tungsten, as well as two conventional contrast elements: iodine and barium. A water-based phantom with vials containing these five elements in solution, as well as different artifact-producing metal structures, was scanned with a DECT scanner capable of rapid operating voltage switching. In the VMS datasets, substantial reductions in the contrast were observed for iodine and barium, which suffered from contrast reductions of 97% and 91%, respectively, at 140 versus 40 keV. In comparison under the same conditions, the candidate agents demonstrated contrast enhancement reductions of only 20%, 29%, and 32% for tungsten, tantalum, and bismuth, respectively. At 140 versus 40 keV, metal artifact severity was reduced by 57% to 85% depending on the phantom configuration. PMID:26839905

  8. A new approach to synchrotron energy-dispersive X-ray diffraction computed tomography.

    PubMed

    Lazzari, Olivier; Egan, Christopher K; Jacques, Simon D M; Sochi, Taha; Di Michiel, Marco; Cernik, Robert J; Barnes, Paul

    2012-07-01

    A new data collection strategy for performing synchrotron energy-dispersive X-ray diffraction computed tomography has been devised. This method is analogous to angle-dispersive X-ray diffraction whose diffraction signal originates from a line formed by intersection of the incident X-ray beam and the sample. Energy resolution is preserved by using a collimator which defines a small sampling voxel. This voxel is translated in a series of parallel straight lines covering the whole sample and the operation is repeated at different rotation angles, thus generating one diffraction pattern per translation and rotation step. The method has been tested by imaging a specially designed phantom object, devised to be a demanding validator for X-ray diffraction imaging. The relative strengths and weaknesses of the method have been analysed with respect to the classic angle-dispersive technique. The reconstruction accuracy of the method is good, although an absorption correction is required for lower energy diffraction because of the large path lengths involved. The spatial resolution is only limited to the width of the scanning beam owing to the novel collection strategy. The current temporal resolution is poor, with a scan taking several hours. The method is best suited to studying large objects (e.g. for engineering and materials science applications) because it does not suffer from diffraction peak broadening effects irrespective of the sample size, in contrast to the angle-dispersive case.

  9. Methods of determining loads and fiber orientations in anisotropic non-crystalline materials using energy flux deviation

    NASA Technical Reports Server (NTRS)

    Prosser, William H. (Inventor); Kriz, Ronald D. (Inventor); Fitting, Dale W. (Inventor)

    1993-01-01

    An ultrasonic wave is applied to an anisotropic sample material in an initial direction and an angle of flux deviation of the ultrasonic wave front is measured from this initial direction. This flux deviation angle is induced by the unknown applied load. The flux shift is determined between this flux deviation angle and a previously determined angle of flux deviation of an ultrasonic wave applied to a similar anisotropic reference material under an initial known load condition. This determined flux shift is then compared to a plurality of flux shifts of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift.

  10. Grand Challenges of Advanced Computing for Energy Innovation Report from the Workshop Held July 31-August 2, 2012

    SciTech Connect

    Larzelere, Alex R.; Ashby, Steven F.; Christensen, Dana C.; Crawford, Dona L.; Khaleel, Mohammad A.; John, Grosh; Stults, B. Ray; Lee, Steven L.; Hammond, Steven W.; Grover, Benjamin T.; Neely, Rob; Dudney, Lee Ann; Goldstein, Noah C.; Wells, Jack; Peltz, Jim

    2013-03-06

    On July 31-August 2 of 2012, the U.S. Department of Energy (DOE) held a workshop entitled Grand Challenges of Advanced Computing for Energy Innovation. This workshop built on three earlier workshops that clearly identified the potential for the Department and its national laboratories to enable energy innovation. The specific goal of the workshop was to identify the key challenges that the nation must overcome to apply the full benefit of taxpayer-funded advanced computing technologies to U.S. energy innovation in the ways that the country produces, moves, stores, and uses energy. Perhaps more importantly, the workshop also developed a set of recommendations to help the Department overcome those challenges. These recommendations provide an action plan for what the Department can do in the coming years to improve the nation’s energy future.

  11. Computation of binding energies including their enthalpy and entropy components for protein-ligand complexes using support vector machines.

    PubMed

    Koppisetty, Chaitanya A K; Frank, Martin; Kemp, Graham J L; Nyholm, Per-Georg

    2013-10-28

    Computing binding energies of protein-ligand complexes including their enthalpy and entropy terms by means of computational methods is an appealing approach for selecting initial hits and for further optimization in early stages of drug discovery. Despite the importance, computational predictions of thermodynamic components have evaded attention and reasonable solutions. In this study, support vector machines are used for developing scoring functions to compute binding energies and their enthalpy and entropy components of protein-ligand complexes. The binding energies computed from our newly derived scoring functions have better Pearson's correlation coefficients with experimental data than previously reported scoring functions in benchmarks for protein-ligand complexes from the PDBBind database. The protein-ligand complexes with binding energies dominated by enthalpy or entropy term could be qualitatively classified by the newly derived scoring functions with high accuracy. Furthermore, it is found that the inclusion of comprehensive descriptors based on ligand properties in the scoring functions improved the accuracy of classification as well as the prediction of binding energies including their thermodynamic components. The prediction of binding energies including the enthalpy and entropy components using the support vector machine based scoring functions should be of value in the drug discovery process.

  12. Analysis of colliding nuclear matter in terms of symmetry energy and cross-section using computational method

    SciTech Connect

    Sharma, Arun Bharti, Arun; Gautam, Sakshi

    2015-08-28

    Here we perform a systematic study to extract the information for colliding nuclear matter via symmetry energy and nucleon-nucleon cross section in the fragmentation of some asymmetric colliding nuclei (O{sup 16}+Br{sup 80,} {sup 84,} {sup 92}) in the energy range between 50-200 MeV/nucleon. The simulations are carried out using isospin-dependent quantum-molecular dynamics (IQMD) computational approach for central collisions. Our study reveals that fragmentation pattern of neutron-rich colliding nuclei is sensitive to symmetry energy at lower incident energies, whereas isospin dependence of nucleon-nucleon cross section becomes dominant for reactions at higher incident energies.

  13. PREFACE: International Conference on Computing in High Energy and Nuclear Physics (CHEP 2010)

    NASA Astrophysics Data System (ADS)

    Lin, Simon C.; Shen, Stella; Neufeld, Niko; Gutsche, Oliver; Cattaneo, Marco; Fisk, Ian; Panzer-Steindel, Bernd; Di Meglio, Alberto; Lokajicek, Milos

    2011-12-01

    The International Conference on Computing in High Energy and Nuclear Physics (CHEP) was held at Academia Sinica in Taipei from 18-22 October 2010. CHEP is a major series of international conferences for physicists and computing professionals from the worldwide High Energy and Nuclear Physics community, Computer Science, and Information Technology. The CHEP conference provides an international forum to exchange information on computing progress and needs for the community, and to review recent, ongoing and future activities. CHEP conferences are held at roughly 18 month intervals, alternating between Europe, Asia, America and other parts of the world. Recent CHEP conferences have been held in Prauge, Czech Republic (2009); Victoria, Canada (2007); Mumbai, India (2006); Interlaken, Switzerland (2004); San Diego, California(2003); Beijing, China (2001); Padova, Italy (2000) CHEP 2010 was organized by Academia Sinica Grid Computing Centre. There was an International Advisory Committee (IAC) setting the overall themes of the conference, a Programme Committee (PC) responsible for the content, as well as Conference Secretariat responsible for the conference infrastructure. There were over 500 attendees with a program that included plenary sessions of invited speakers, a number of parallel sessions comprising around 260 oral and 200 poster presentations, and industrial exhibitions. We thank all the presenters, for the excellent scientific content of their contributions to the conference. Conference tracks covered topics on Online Computing, Event Processing, Software Engineering, Data Stores, and Databases, Distributed Processing and Analysis, Computing Fabrics and Networking Technologies, Grid and Cloud Middleware, and Collaborative Tools. The conference included excursions to various attractions in Northern Taiwan, including Sanhsia Tsu Shih Temple, Yingko, Chiufen Village, the Northeast Coast National Scenic Area, Keelung, Yehliu Geopark, and Wulai Aboriginal Village

  14. Exact charge and energy conservation in implicit PIC with mapped computational meshes

    SciTech Connect

    Chen, Guangye; Barnes, D. C.

    2013-01-01

    This paper discusses a novel fully implicit formulation for a one-dimensional electrostatic particle-in-cell (PIC) plasma simulation approach. Unlike earlier implicit electrostatic PIC approaches (which are based on a linearized Vlasov Poisson formulation), ours is based on a nonlinearly converged Vlasov Amp re (VA) model. By iterating particles and fields to a tight nonlinear convergence tolerance, the approach features superior stability and accuracy properties, avoiding most of the accuracy pitfalls in earlier implicit PIC implementations. In particular, the formulation is stable against temporal (Courant Friedrichs Lewy) and spatial (aliasing) instabilities. It is charge- and energy-conserving to numerical round-off for arbitrary implicit time steps (unlike the earlier energy-conserving explicit PIC formulation, which only conserves energy in the limit of arbitrarily small time steps). While momentum is not exactly conserved, errors are kept small by an adaptive particle sub-stepping orbit integrator, which is instrumental to prevent particle tunneling (a deleterious effect for long-term accuracy). The VA model is orbit-averaged along particle orbits to enforce an energy conservation theorem with particle sub-stepping. As a result, very large time steps, constrained only by the dynamical time scale of interest, are possible without accuracy loss. Algorithmically, the approach features a Jacobian-free Newton Krylov solver. A main development in this study is the nonlinear elimination of the new-time particle variables (positions and velocities). Such nonlinear elimination, which we term particle enslavement, results in a nonlinear formulation with memory requirements comparable to those of a fluid computation, and affords us substantial freedom in regards to the particle orbit integrator. Numerical examples are presented that demonstrate the advertised properties of the scheme. In particular, long-time ion acoustic wave simulations show that numerical accuracy

  15. Event parallelism: Distributed memory parallel computing for high energy physics experiments

    SciTech Connect

    Nash, T.

    1989-05-01

    This paper describes the present and expected future development of distributed memory parallel computers for high energy physics experiments. It covers the use of event parallel microprocessor farms, particularly at Fermilab, including both ACP multiprocessors and farms of MicroVAXES. These systems have proven very cost effective in the past. A case is made for moving to the more open environment of UNIX and RISC processors. The 2nd Generation ACP Multiprocessor System, which is based on powerful RISC systems, is described. Given the promise of still more extraordinary increases in processor performance, a new emphasis on point to point, rather than bussed, communication will be required. Developments in this direction are described. 6 figs.

  16. Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

    PubMed Central

    Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

    2015-01-01

    Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  17. Comparative analysis of economic models in selected solar energy computer programs

    NASA Astrophysics Data System (ADS)

    Powell, J. W.; Barnes, K. A.

    1982-01-01

    The economic evaluation models in five computer programs widely used for analyzing solar energy systems (F-CHART 3.0, F-CHART 4.0, SOLCOST, BLAST, and DOE-2) are compared. Differences in analysis techniques and assumptions among the programs are assessed from the point of view of consistency with the Federal requirements for life cycle costing (10 CFR Part 436), effect on predicted economic performance, and optimal system size, case of use, and general applicability to diverse systems types and building types. The FEDSOL program developed by the National Bureau of Standards specifically to meet the Federal life cycle cost requirements serves as a basis for the comparison. Results of the study are illustrated in test cases of two different types of Federally owned buildings: a single family residence and a low rise office building.

  18. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    PubMed Central

    Ding, Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-01-01

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of −11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis. PMID:23718593

  19. The application of dual-energy computed tomography in the diagnosis of acute gouty arthritis.

    PubMed

    Wu, Huaxiang; Xue, Jing; Ye, Lu; Zhou, Qijing; Shi, Dan; Xu, Rongzhen

    2014-07-01

    The aim of the study was to investigate the sensitivity and specificity of dual-energy computed tomography in the diagnosis of acute gouty arthritis, and the related risk factors for urate crystal deposition. One hundred ninety-one patients (143 with acute gouty arthritis and 48 with other arthritic conditions) were studied. All patients had acute arthritic attack in the recent 15 days and underwent dual-energy computed tomography (DECT) scan with the affected joints. The urate volume was calculated by DECT and the basic information of these patients was recorded at the same time. Uric acid crystals were identified with DECT in 140 of 143 (97.9 %) gout patients and 6 of 48 (12.5 %) of nongout patients, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of DECT in the diagnosis of acute gouty arthritis were 97.9, 87.5, 95.9, and 93.3 %, respectively. The urate volumes were ranged from 0.57 to 54,543.27 mm(3) with a mean volume of 1,787.81 ± 7,181.54 mm(3). Interestingly, urate volume was correlated with the disease duration, serum uric acid levels, the presence of tophi, and bone erosion. Two-year follow-up data was available in one patient with recurrent gouty arthritis, whose urate volume was gradually reduced in size by DECT detection after urate-lowering therapies. DECT showed high sensitivity and specificity for the identification of urate crystals and diagnosis of acute gout. The risk factors for uric acid deposition include the disease duration, serum uric acid levels, the presence of tophi, and bone erosion. DECT has an important role in the differential diagnosis of arthritis, and also could be served as a follow-up tool.

  20. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    SciTech Connect

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-06-15

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of -11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis.

  1. FireProt: Energy- and Evolution-Based Computational Design of Thermostable Multiple-Point Mutants

    PubMed Central

    Sebestova, Eva; Bendl, Jaroslav; Khare, Sagar; Chaloupkova, Radka; Prokop, Zbynek; Brezovsky, Jan; Baker, David; Damborsky, Jiri

    2015-01-01

    There is great interest in increasing proteins’ stability to enhance their utility as biocatalysts, therapeutics, diagnostics and nanomaterials. Directed evolution is a powerful, but experimentally strenuous approach. Computational methods offer attractive alternatives. However, due to the limited reliability of predictions and potentially antagonistic effects of substitutions, only single-point mutations are usually predicted in silico, experimentally verified and then recombined in multiple-point mutants. Thus, substantial screening is still required. Here we present FireProt, a robust computational strategy for predicting highly stable multiple-point mutants that combines energy- and evolution-based approaches with smart filtering to identify additive stabilizing mutations. FireProt’s reliability and applicability was demonstrated by validating its predictions against 656 mutations from the ProTherm database. We demonstrate that thermostability of the model enzymes haloalkane dehalogenase DhaA and γ-hexachlorocyclohexane dehydrochlorinase LinA can be substantially increased (ΔT m = 24°C and 21°C) by constructing and characterizing only a handful of multiple-point mutants. FireProt can be applied to any protein for which a tertiary structure and homologous sequences are available, and will facilitate the rapid development of robust proteins for biomedical and biotechnological applications. PMID:26529612

  2. Computational Discovery of Metal-Organic Frameworks for CO2 Capture and Energy Storage

    NASA Astrophysics Data System (ADS)

    Siegel, Donald

    2015-03-01

    Because of their high surface areas, crystallinity, and tunable properties, metal -organic frameworks (MOFs) have attracted intense interest as materials for gas capture and energy storage. An often-cited benefit of MOFs is their large number of possible structures and compositions. Nevertheless, this design flexibility also has drawbacks, as pinpointing optimal compounds from thousands of candidates can be time consuming and costly using experimental approaches. Consequently, computational approaches are garnering increasing importance as a means to accelerate the discovery of high-performing MOFs. Here we combine several computational techniques to identify promising MOFs for CO2 capture and the storage of gaseous fuels (methane and hydrogen). The techniques include: (i) high-throughput screening based on data-mining and empirical correlations; (ii) Monte Carlo simulations based on quantum-mechanically-informed forcefields; and (iii) first-principles calculations of thermodynamics and electronic structure. For CO2 capture and CH4 storage, these techniques are used to explore metal-substituted variants of M-DOBDC and M-HKUST-1. In the case of H2, we identify trends and promising adsorbents amongst 4,000 compounds mined from the Cambridge Structure Database.

  3. Open-cycle ocean thermal energy conversion surface-condenser design analysis and computer program

    SciTech Connect

    Panchal, C.B.; Rabas, T.J.

    1991-05-01

    This report documents a computer program for designing a surface condenser that condenses low-pressure steam in an ocean thermal energy conversion (OTEC) power plant. The primary emphasis is on the open-cycle (OC) OTEC power system, although the same condenser design can be used for conventional and hybrid cycles because of their highly similar operating conditions. In an OC-OTEC system, the pressure level is very low (deep vacuums), temperature differences are small, and the inlet noncondensable gas concentrations are high. Because current condenser designs, such as the shell-and-tube, are not adequate for such conditions, a plate-fin configuration is selected. This design can be implemented in aluminum, which makes it very cost-effective when compared with other state-of-the-art vacuum steam condenser designs. Support for selecting a plate-fin heat exchanger for OC-OTEC steam condensation can be found in the sizing (geometric details) and rating (heat transfer and pressure drop) calculations presented. These calculations are then used in a computer program to obtain all the necessary thermal performance details for developing design specifications for a plate-fin steam condenser. 20 refs., 5 figs., 5 tabs.

  4. Open-cycle ocean thermal energy conversion surface-condenser design analysis and computer program

    NASA Astrophysics Data System (ADS)

    Panchal, C. B.; Rabas, T. J.

    1991-05-01

    This report documents a computer program for designing a surface condenser that condenses low-pressure steam in an ocean thermal energy conversion (OTEC) power plant. The primary emphasis is on the open-cycle (OC) OTEC power system, although the same condenser design can be used for conventional and hybrid cycles because of their highly similar operating conditions. In an OC-OTEC system, the pressure level is very low (deep vacuums), temperature differences are small, and the inlet noncondensable gas concentrations are high. Because current condenser designs, such as the shell-and-tube, are not adequate for such conditions, a plate-fin configuration is selected. This design can be implemented in aluminum, which makes it very cost-effective when compared with other state-of-the-art vacuum steam condenser designs. Support for selecting a plate-fin heat exchanger for OC-OTEC steam condensation can be found in the sizing (geometric details) and rating (heat transfer and pressure drop) calculations presented. These calculations are then used in a computer program to obtain all the necessary thermal performance details for developing design specifications for a plate-fin steam condenser.

  5. Structural Models of Zebrafish (Danio rerio) NOD1 and NOD2 NACHT Domains Suggest Differential ATP Binding Orientations: Insights from Computational Modeling, Docking and Molecular Dynamics Simulations

    PubMed Central

    Maharana, Jitendra; Sahoo, Bikash Ranjan; Bej, Aritra; Sahoo, Jyoti Ranjan; Dehury, Budheswar; Patra, Mahesh Chandra; Martha, Sushma Rani; Balabantray, Sucharita; Pradhan, Sukanta Kumar; Behera, Bijay Kumar

    2015-01-01

    Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) and NOD2 are cytosolic pattern recognition receptors playing pivotal roles in innate immune signaling. NOD1 and NOD2 recognize bacterial peptidoglycan derivatives iE-DAP and MDP, respectively and undergoes conformational alternation and ATP-dependent self-oligomerization of NACHT domain followed by downstream signaling. Lack of structural adequacy of NACHT domain confines our understanding about the NOD-mediated signaling mechanism. Here, we predicted the structure of NACHT domain of both NOD1 and NOD2 from model organism zebrafish (Danio rerio) using computational methods. Our study highlighted the differential ATP binding modes in NOD1 and NOD2. In NOD1, γ-phosphate of ATP faced toward the central nucleotide binding cavity like NLRC4, whereas in NOD2 the cavity was occupied by adenine moiety. The conserved ‘Lysine’ at Walker A formed hydrogen bonds (H-bonds) and Aspartic acid (Walker B) formed electrostatic interaction with ATP. At Sensor 1, Arg328 of NOD1 exhibited an H-bond with ATP, whereas corresponding Arg404 of NOD2 did not. ‘Proline’ of GxP motif (Pro386 of NOD1 and Pro464 of NOD2) interacted with adenine moiety and His511 at Sensor 2 of NOD1 interacted with γ-phosphate group of ATP. In contrast, His579 of NOD2 interacted with the adenine moiety having a relatively inverted orientation. Our findings are well supplemented with the molecular interaction of ATP with NLRC4, and consistent with mutagenesis data reported for human, which indicates evolutionary shared NOD signaling mechanism. Together, this study provides novel insights into ATP binding mechanism, and highlights the differential ATP binding modes in zebrafish NOD1 and NOD2. PMID:25811192

  6. Soft computing analysis of the possible correlation between temporal and energy release patterns in seismic activity

    NASA Astrophysics Data System (ADS)

    Konstantaras, Anthony; Katsifarakis, Emmanouil; Artzouxaltzis, Xristos; Makris, John; Vallianatos, Filippos; Varley, Martin

    2010-05-01

    This paper is a preliminary investigation of the possible correlation of temporal and energy release patterns of seismic activity involving the preparation processes of consecutive sizeable seismic events [1,2]. The background idea is that during periods of low-level seismic activity, stress processes in the crust accumulate energy at the seismogenic area whilst larger seismic events act as a decongesting mechanism releasing considerable energy [3,4]. A dynamic algorithm is being developed aiming to identify and cluster pre- and post- seismic events to the main earthquake following on research carried out by Zubkov [5] and Dobrovolsky [6,7]. This clustering technique along with energy release equations dependent on Richter's scale [8,9] allow for an estimate to be drawn regarding the amount of the energy being released by the seismic sequence. The above approach is being implemented as a monitoring tool to investigate the behaviour of the underlying energy management system by introducing this information to various neural [10,11] and soft computing models [1,12,13,14]. The incorporation of intelligent systems aims towards the detection and simulation of the possible relationship between energy release patterns and time-intervals among consecutive sizeable earthquakes [1,15]. Anticipated successful training of the imported intelligent systems may result in a real-time, on-line processing methodology [1,16] capable to dynamically approximate the time-interval between the latest and the next forthcoming sizeable seismic event by monitoring the energy release process in a specific seismogenic area. Indexing terms: pattern recognition, long-term earthquake precursors, neural networks, soft computing, earthquake occurrence intervals References [1] Konstantaras A., Vallianatos F., Varley M.R. and Makris J. P.: ‘Soft computing modelling of seismicity in the southern Hellenic arc', IEEE Geoscience and Remote Sensing Letters, vol. 5 (3), pp. 323-327, 2008 [2] Eneva M. and

  7. Field-SEA: a model for computing the solvation free energies of nonpolar, polar, and charged solutes in water.

    PubMed

    Li, Libo; Fennell, Christopher J; Dill, Ken A

    2014-06-19

    Previous work describes a computational solvation model called semi-explicit assembly (SEA). The SEA water model computes the free energies of solvation of nonpolar and polar solutes in water with good efficiency and accuracy. However, SEA gives systematic errors in the solvation free energies of ions and charged solutes. Here, we describe field-SEA, an improved treatment that gives accurate solvation free energies of charged solutes, including monatomic and polyatomic ions and model dipeptides, as well as nonpolar and polar molecules. Field-SEA is computationally inexpensive for a given solute because explicit-solvent model simulations are relegated to a precomputation step and because it represents solvating waters in terms of a solute's free-energy field. In essence, field-SEA approximates the physics of explicit-model simulations within a computationally efficient framework. A key finding is that an atom's solvation shell inherits characteristics of a neighboring atom, especially strongly charged neighbors. Field-SEA may be useful where there is a need for solvation free-energy computations that are faster than explicit-solvent simulations and more accurate than traditional implicit-solvent simulations for a wide range of solutes.

  8. Energy effects associated with e-commerce: a case-study concerning online sales of personal computers in The Netherlands.

    PubMed

    Reijnders, L; Hoogeveen, M J

    2001-07-01

    The introduction of e-commerce is changing purchase and distribution patterns dramatically. One of the observed effects is that logistics become more efficient as products are directly shipped from a manufacturer or wholesaler to an end-user. Another effect is that market transparency increases, which has a downward pressure on prices of many products sold via the Internet. This article addresses the energy implications of e-commerce at the micro level. This is done by quantifying the transport related energy savings in the case of a Dutch online computer reseller and by assessing the extra energy expenditure associated with increased buying power of online buyers. It is found that energy use per article sold by the online computer reseller is lower. However, taking into account indirect effects such as increased consumer buying power, there are scenarios that lead to an overall increase in energy use.

  9. Verification of energy dissipation rate scalability in pilot and production scale bioreactors using computational fluid dynamics.

    PubMed

    Johnson, Chris; Natarajan, Venkatesh; Antoniou, Chris

    2014-01-01

    Suspension mammalian cell cultures in aerated stirred tank bioreactors are widely used in the production of monoclonal antibodies. Given that production scale cell culture operations are typically performed in very large bioreactors (≥ 10,000 L), bioreactor scale-down and scale-up become crucial in the development of robust cell-culture processes. For successful scale-up and scale-down of cell culture operations, it is important to understand the scale-dependence of the distribution of the energy dissipation rates in a bioreactor. Computational fluid dynamics (CFD) simulations can provide an additional layer of depth to bioreactor scalability analysis. In this communication, we use CFD analyses of five bioreactor configurations to evaluate energy dissipation rates and Kolmogorov length scale distributions at various scales. The results show that hydrodynamic scalability is achievable as long as major design features (# of baffles, impellers) remain consistent across the scales. Finally, in all configurations, the mean Kolmogorov length scale is substantially higher than the average cell size, indicating that catastrophic cell damage due to mechanical agitation is highly unlikely at all scales.

  10. System-independent characterization of materials using dual-energy computed tomography

    SciTech Connect

    Azevedo, Stephen G.; Martz, Jr., Harry E.; Aufderheide, III, Maurice B.; Brown, William D.; Champley, Kyle M.; Kallman, Jeffrey S.; Roberson, G. Patrick; Schneberk, Daniel; Seetho, Isaac M.; Smith, Jerel A.

    2016-02-01

    In this study, we present a new decomposition approach for dual-energy computed tomography (DECT) called SIRZ that provides precise and accurate material description, independent of the scanner, over diagnostic energy ranges (30 to 200 keV). System independence is achieved by explicitly including a scanner-specific spectral description in the decomposition method, and a new X-ray-relevant feature space. The feature space consists of electron density, ρe, and a new effective atomic number, Ze, which is based on published X-ray cross sections. Reference materials are used in conjunction with the system spectral response so that additional beam-hardening correction is not necessary. The technique is tested against other methods on DECT data of known specimens scanned by diverse spectra and systems. Uncertainties in accuracy and precision are less than 3% and 2% respectively for the (ρe, Ze) results compared to prior methods that are inaccurate and imprecise (over 9%).

  11. System-independent characterization of materials using dual-energy computed tomography

    DOE PAGES

    Azevedo, Stephen G.; Martz, Jr., Harry E.; Aufderheide, III, Maurice B.; ...

    2016-02-01

    In this study, we present a new decomposition approach for dual-energy computed tomography (DECT) called SIRZ that provides precise and accurate material description, independent of the scanner, over diagnostic energy ranges (30 to 200 keV). System independence is achieved by explicitly including a scanner-specific spectral description in the decomposition method, and a new X-ray-relevant feature space. The feature space consists of electron density, ρe, and a new effective atomic number, Ze, which is based on published X-ray cross sections. Reference materials are used in conjunction with the system spectral response so that additional beam-hardening correction is not necessary. The techniquemore » is tested against other methods on DECT data of known specimens scanned by diverse spectra and systems. Uncertainties in accuracy and precision are less than 3% and 2% respectively for the (ρe, Ze) results compared to prior methods that are inaccurate and imprecise (over 9%).« less

  12. Computer-aided analysis of energy consumption in ethanol-water distillation operations

    NASA Astrophysics Data System (ADS)

    Nguyen, X. N.; Heyman, E. C.

    1982-02-01

    Existing computer programs have been used to evaluate the effects of various process parameters on the energy consumption of an ethanol distillation step. A savings of 250 kJ/mol ethanol produced is possible if the ethanol feed concentration is increased from 4 wt % to 8 wt %; further increases, however, result in only marginal additional savings. Preheating the feed to its saturated liquid condition is more advantageous than distilling the cold feed directly; the reboiler requires substantially less energy if the waste heat in the bottom flow is used to preheat the feed. About $45,000/y could be saved by a 38 ML/y plant by decreasing the operating reflux from 1.5 to 1.3 times the minimum reflux ratio. At ethanol concentrations above 15 wt %, about 40 kJ/mol ethanol produced could be saved by reducing the concentration of the ethanol feed to the dehydrating column to 92 wt %. Operating at 10 kPa (0.1 atm) instead of 100 kPa (1 atm) could save 125 kJ/mol ethanol produced, but an increase in noncondensible gases could lead to increased steam usage.

  13. Polynomial chaos for the computation of annual energy production in wind farm layout optimization

    NASA Astrophysics Data System (ADS)

    Padrón, A. S.; Stanley, A. P. J.; Thomas, J. J.; Alonso, J. J.; Ning, A.

    2016-09-01

    Careful management of wake interference is essential to further improve Annual Energy Production (AEP) of wind farms. Wake effects can be minimized through optimization of turbine layout, wind farm control, and turbine design. Realistic wind farm optimization is challenging because it has numerous design degrees of freedom and must account for the stochastic nature of wind. In this paper we provide a framework for calculating AEP for any relevant uncertain (stochastic) variable of interest. We use Polynomial Chaos (PC) to efficiently quantify the effect of the stochastic variables—wind direction and wind speed—on the statistical outputs of interest (AEP) for wind farm layout optimization. When the stochastic variable includes the wind direction, polynomial chaos is one order of magnitude more accurate in computing the AEP when compared to commonly used simplistic integration techniques (rectangle rule), especially for non grid-like wind farm layouts. Furthermore, PC requires less simulations for the same accuracy. This allows for more efficient optimization and uncertainty quantification of wind farm energy production.

  14. Computation of the binding free energy of peptides to graphene in explicit water.

    PubMed

    Welch, Corrinne M; Camden, Aerial N; Barr, Stephen A; Leuty, Gary M; Kedziora, Gary S; Berry, Rajiv J

    2015-07-28

    The characteristic properties of graphene make it useful in an assortment of applications. One particular application--the use of graphene in biosensors--requires a thorough understanding of graphene-peptide interactions. In this study, the binding of glycine (G) capped amino acid residues (termed GXG tripeptides) to trilayer graphene surfaces in aqueous solution was examined and compared to results previously obtained for peptide binding to single-layer free-standing graphene [A. N. Camden, S. A. Barr, and R. J. Berry, J. Phys. Chem. B 117, 10691-10697 (2013)]. In order to understand the interactions between the peptides and the surface, binding enthalpy and free energy values were calculated for each GXG system, where X cycled through the typical 20 amino acids. When the GXG tripeptides were bound to the surface, distinct conformations were observed, each with a different binding enthalpy. Analysis of the binding energy showed the binding of peptides to trilayer graphene was dominated by van der Waals interactions, unlike the free-standing graphene systems, where the binding was predominantly electrostatic in nature. These results demonstrate the utility of computational materials science in the mechanistic explanation of surface-biomolecule interactions which could be applied to a wide range of systems.

  15. CO2, energy and economy interactions: A multisectoral, dynamic, computable general equilibrium model for Korea

    NASA Astrophysics Data System (ADS)

    Kang, Yoonyoung

    While vast resources have been invested in the development of computational models for cost-benefit analysis for the "whole world" or for the largest economies (e.g. United States, Japan, Germany), the remainder have been thrown together into one model for the "rest of the world." This study presents a multi-sectoral, dynamic, computable general equilibrium (CGE) model for Korea. This research evaluates the impacts of controlling COsb2 emissions using a multisectoral CGE model. This CGE economy-energy-environment model analyzes and quantifies the interactions between COsb2, energy and economy. This study examines interactions and influences of key environmental policy components: applied economic instruments, emission targets, and environmental tax revenue recycling methods. The most cost-effective economic instrument is the carbon tax. The economic effects discussed include impacts on main macroeconomic variables (in particular, economic growth), sectoral production, and the energy market. This study considers several aspects of various COsb2 control policies, such as the basic variables in the economy: capital stock and net foreign debt. The results indicate emissions might be stabilized in Korea at the expense of economic growth and with dramatic sectoral allocation effects. Carbon dioxide emissions stabilization could be achieved to the tune of a 600 trillion won loss over a 20 year period (1990-2010). The average annual real GDP would decrease by 2.10% over the simulation period compared to the 5.87% increase in the Business-as-Usual. This model satisfies an immediate need for a policy simulation model for Korea and provides the basic framework for similar economies. It is critical to keep the central economic question at the forefront of any discussion regarding environmental protection. How much will reform cost, and what does the economy stand to gain and lose? Without this model, the policy makers might resort to hesitation or even blind speculation. With

  16. Tophaceous Gout in an Anorectic Patient Visualized by Dual Energy Computed Tomography (DECT)

    PubMed Central

    Christensen, Heidi Dahl; Sheta, Hussam Mahmoud; Morillon, Melanie Birger; Hansen, Inger Marie Jensen

    2016-01-01

    Patient: Female, 40 Final Diagnosis: Gout Symptoms: Joint pain Medication: — Clinical Procedure: Dual energy Computed tomography Specialty: Rheumatology Objective: Rare co-existance of disease or pathology Background: Gout is characterized by deposition of uric acid crystals (monosodium urate) in tissues and fluids. This can cause acute inflammatory arthritis. The 2015 ACR/EULAR criteria for the diagnosis of gout include dual energy computed tomography (DECT)-demonstrated monosodium urate crystals as a new criterion. DECT is a spectral decomposition that permits recognition of different types of tissues based on their characteristic energy-dependent photon attenuation. A positive scan is defined as the presence of urate at articular or periarticular sites. Case Report: We describe a 51-year-old woman known to have anorexia nervosa. During our clinical examination, we detected plenty of tophi on both hands, but no swollen joints. The diagnosis of gout was made by visualizing crystals in a biopsy from a tophus. The first line of treatment was allopurinol, the second line was rasburicase, and the current treatment is febuxostat 80 mg/day, allopurinol 300 mg twice a day, and colchicine 0.5 mg twice a day. The patient has unchanged arthralgia and the size and number of tophi remain the same as before treatment in spite of active treatment for 3 years. Previously the patient had problems with adherence, but now she claims that she follows the proposed treatment. The last plasma urate (P-urate) was 0.57 mmol/L. Following two years of treatment, DECT of hands visualized monosodium urate crystal deposits in the tophi, as seen on the clinical photos, but also crystals in relation to the tendons and soft tissue. Conclusions: DECT is an imaging modality useful to assess urate crystal deposits at diagnosis of gout and could be considered during treatment evaluation. Lack of adherence to treatment should be considered when P-urate values vary significantly and when DECT scans

  17. Segmentation and quantification of materials with energy discriminating computed tomography: A phantom study

    SciTech Connect

    Le, Huy Q.; Molloi, Sabee

    2011-01-15

    Purpose: To experimentally investigate whether a computed tomography (CT) system based on CdZnTe (CZT) detectors in conjunction with a least-squares parameter estimation technique can be used to decompose four different materials. Methods: The material decomposition process was divided into a segmentation task and a quantification task. A least-squares minimization algorithm was used to decompose materials with five measurements of the energy dependent linear attenuation coefficients. A small field-of-view energy discriminating CT system was built. The CT system consisted of an x-ray tube, a rotational stage, and an array of CZT detectors. The CZT array was composed of 64 pixels, each of which is 0.8x0.8x3 mm. Images were acquired at 80 kVp in fluoroscopic mode at 50 ms per frame. The detector resolved the x-ray spectrum into energy bins of 22-32, 33-39, 40-46, 47-56, and 57-80 keV. Four phantoms were constructed from polymethylmethacrylate (PMMA), polyethylene, polyoxymethylene, hydroxyapatite, and iodine. Three phantoms were composed of three materials with embedded hydroxyapatite (50, 150, 250, and 350 mg/ml) and iodine (4, 8, 12, and 16 mg/ml) contrast elements. One phantom was composed of four materials with embedded hydroxyapatite (150 and 350 mg/ml) and iodine (8 and 16 mg/ml). Calibrations consisted of PMMA phantoms with either hydroxyapatite (100, 200, 300, 400, and 500 mg/ml) or iodine (5, 15, 25, 35, and 45 mg/ml) embedded. Filtered backprojection and a ramp filter were used to reconstruct images from each energy bin. Material segmentation and quantification were performed and compared between different phantoms. Results: All phantoms were decomposed accurately, but some voxels in the base material regions were incorrectly identified. Average quantification errors of hydroxyapatite/iodine were 9.26/7.13%, 7.73/5.58%, and 12.93/8.23% for the three-material PMMA, polyethylene, and polyoxymethylene phantoms, respectively. The average errors for the four

  18. Segmentation and quantification of materials with energy discriminating computed tomography: A phantom study

    PubMed Central

    Le, Huy Q.; Molloi, Sabee

    2011-01-01

    Purpose: To experimentally investigate whether a computed tomography (CT) system based on CdZnTe (CZT) detectors in conjunction with a least-squares parameter estimation technique can be used to decompose four different materials. Methods: The material decomposition process was divided into a segmentation task and a quantification task. A least-squares minimization algorithm was used to decompose materials with five measurements of the energy dependent linear attenuation coefficients. A small field-of-view energy discriminating CT system was built. The CT system consisted of an x-ray tube, a rotational stage, and an array of CZT detectors. The CZT array was composed of 64 pixels, each of which is 0.8×0.8×3 mm. Images were acquired at 80 kVp in fluoroscopic mode at 50 ms per frame. The detector resolved the x-ray spectrum into energy bins of 22–32, 33–39, 40–46, 47–56, and 57–80 keV. Four phantoms were constructed from polymethylmethacrylate (PMMA), polyethylene, polyoxymethylene, hydroxyapatite, and iodine. Three phantoms were composed of three materials with embedded hydroxyapatite (50, 150, 250, and 350 mg∕ml) and iodine (4, 8, 12, and 16 mg∕ml) contrast elements. One phantom was composed of four materials with embedded hydroxyapatite (150 and 350 mg∕ml) and iodine (8 and 16 mg∕ml). Calibrations consisted of PMMA phantoms with either hydroxyapatite (100, 200, 300, 400, and 500 mg∕ml) or iodine (5, 15, 25, 35, and 45 mg∕ml) embedded. Filtered backprojection and a ramp filter were used to reconstruct images from each energy bin. Material segmentation and quantification were performed and compared between different phantoms. Results: All phantoms were decomposed accurately, but some voxels in the base material regions were incorrectly identified. Average quantification errors of hydroxyapatite∕iodine were 9.26∕7.13%, 7.73∕5.58%, and 12.93∕8.23% for the three-material PMMA, polyethylene, and polyoxymethylene phantoms, respectively. The

  19. Energy Management of the Multi-Mission Space Exploration Vehicle Using a Goal-Oriented Control System

    NASA Technical Reports Server (NTRS)

    Braman, Julia M. B.; Wagner, David A.

    2010-01-01

    Safe human exploration in space missions requires careful management of limited resources such as breathable air and stored electrical energy. Daily activities for astronauts must be carefully planned with respect to such resources, and usage must be monitored as activities proceed to ensure that they can be completed while maintaining safe resource margins. Such planning and monitoring can be complex because they depend on models of resource usage, the activities being planned, and uncertainties. This paper describes a system - and the technology behind it - for energy management of the NASA-Johnson Space Center's Multi-Mission Space Exploration Vehicles (SEV), that provides, in an onboard advisory mode, situational awareness to astronauts and real-time guidance to mission operators. This new capability was evaluated during this year's Desert RATS (Research and Technology Studies) planetary exploration analog test in Arizona. This software aided ground operators and crew members in modifying the day s activities based on the real-time execution of the plan and on energy data received from the rovers.

  20. Orienteering injuries

    PubMed Central

    Folan, Jean M.

    1982-01-01

    At the Irish National Orienteering Championships in 1981 a survey of the injuries occurring over the two days of competition was carried out. Of 285 individual competitors there was a percentage injury rate of 5.26%. The article discusses the injuries and aspects of safety in orienteering. Imagesp236-ap237-ap237-bp238-ap239-ap240-a PMID:7159815

  1. Digital computer simulation of inductor-energy-storage dc-to-dc converters with closed-loop regulators

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Owen, H. A.; Wilson, T. G.; Rodriguez, G. E.

    1974-01-01

    The simulation of converter-controller combinations by means of a flexible digital computer program which produces output to a graphic display is discussed. The procedure is an alternative to mathematical analysis of converter systems. The types of computer programming involved in the simulation are described. Schematic diagrams, state equations, and output equations are displayed for four basic forms of inductor-energy-storage dc to dc converters. Mathematical models are developed to show the relationship of the parameters.

  2. Planning and drilling geothermal energy extraction hole EE-2: a precisely oriented and deviated hole in hot granitic rock

    SciTech Connect

    Helmick, C.; Koczan, S.; Pettitt, R.

    1982-04-01

    During the preceding work (Phase I) of the Hot Dry Rock (HDR) Geothermal Energy Project at Fenton Hill, two holes were drilled to a depth of nearly 3048 m (10,000 ft) and connected by a vertical hydraulic fracture. In this phase, water was pumped through the underground reservoir for approximately 417 days, producing an energy equivalent of 3 to 5 MW(t). Energy Extraction Hole No. 2 (EE-2) is the first of two deep holes that will be used in the Engineering-Resource Development System (Phase II) of the ongoing HDR Project of the Los Alamos National Laboratory. This phase of the work consists of drilling two parallel boreholes, inclined in their lower, open-hole sections at 35/sup 0/ to the vertical and separated by a vertical distance of 366 m (1200 ft) between the inclined parts of the drill holes. The holes will be connected by a series of vertical, hydraulically produced fractures in the Precambrian granitic rock complex. EE-2 was drilled to a depth of 4660 m (15,289 ft), where the bottom-hole temperature is approximately 320/sup 0/C (608/sup 0/F). Directional drilling techniques were used to control the azimuth and deviation of the hole. Upgrading of the temperature capability of existing hardware, and development of new equipment was necessary to complete the drilling of the hole in the extremely hot, hard, and abrasive granitic formation. The drilling history and the problems with bits, directional tools, tubular goods, cementing, and logging are described. A discussion of the problems and recommendations for overcoming them are also presented.

  3. Experimental and Computational Studies of High Energy Density Plasma Streams Ablated from Fine Wires

    SciTech Connect

    Greenly, John B.; Seyler, Charles

    2014-03-30

    Experimental and computational studies of high energy density plasma streams ablated from fine wires. Laboratory of Plasma Studies, School of Electrical and Computer Engineering, Cornell University. Principal Investigators: Dr. John B. Greenly and Dr. Charles E. Seyler. This report summarizes progress during the final year of this project to study the physics of high energy density (HED) plasma streams of 10^17-10^20/cm3 density and high velocity (~100-500 km/s). Such streams are produced from 5-250 micrometer diameter wires heated and ionized by a 1 MA, 250 ns current pulse on the COBRA pulsed power facility at Cornell University. Plasma is ablated from the wires and is driven away to high velocity by unbalanced JxB force. A wire, or an array of wires, can persist as an essentially stationary, continuous source of this streaming plasma for >200 ns, even with driving magnetic fields of many Tesla and peak current densities in the plasma of many MA/cm2. At the heart of the ablation stream generation is the continuous transport of mass from the relatively cold, near-solid-density wire "core" into current-carrying plasma within 1 mm of the wire, followed by the magnetic acceleration of that plasma and its trapped flux to form a directed stream. In the first two years of this program, an advancing understanding of ablation physics led to the discovery of several novel wire ablation experimental regimes. In the final year, one of these new HED plasma regimes has been studied in quantitative detail. This regime studies highly reproducible magnetic reconnection in strongly radiating plasma with supersonic and superalfvenic flow, and shock structures in the outflow. The key discovery is that very heavy wires, e.g. 250 micrometer diameter Al or 150 micrometer Cu, behave in a qualitatively different way than the lighter wires typically used in wire-array Z-pinches. Such wires can be configured to produce a static magnetic X-point null geometry that stores magnetic and

  4. THE SAP3 COMPUTER PROGRAM FOR QUANTITATIVE MULTIELEMENT ANALYSIS BY ENERGY DISPERSIVE X-RAY FLUORESCENCE

    SciTech Connect

    Nielson, K. K.; Sanders, R. W.

    1982-04-01

    SAP3 is a dual-function FORTRAN computer program which performs peak analysis of energy-dispersive x-ray fluorescence spectra and then quantitatively interprets the results of the multielement analysis. It was written for mono- or bi-chromatic excitation as from an isotopic or secondary excitation source, and uses the separate incoherent and coherent backscatter intensities to define the bulk sample matrix composition. This composition is used in performing fundamental-parameter matrix corrections for self-absorption, enhancement, and particle-size effects, obviating the need for specific calibrations for a given sample matrix. The generalized calibration is based on a set of thin-film sensitivities, which are stored in a library disk file and used for all sample matrices and thicknesses. Peak overlap factors are also determined from the thin-film standards, and are stored in the library for calculating peak overlap corrections. A detailed description is given of the algorithms and program logic, and the program listing and flow charts are also provided. An auxiliary program, SPCAL, is also given for use in calibrating the backscatter intensities. SAP3 provides numerous analysis options via seventeen control switches which give flexibility in performing the calculations best suited to the sample and the user needs. User input may be limited to the name of the library, the analysis livetime, and the spectrum filename and location. Output includes all peak analysis information, matrix correction factors, and element concentrations, uncertainties and detection limits. Twenty-four elements are typically determined from a 1024-channel spectrum in one-to-two minutes using a PDP-11/34 computer operating under RSX-11M.

  5. A statistical iterative reconstruction framework for dual energy computed tomography without knowing tube spectrum

    NASA Astrophysics Data System (ADS)

    Chang, Shaojie; Mou, Xuanqin

    2016-09-01

    Dual energy computed tomography (DECT) has significant impacts on material characterization, bone mineral density inspection, nondestructive evaluation and so on. In spite of great progress has been made recently on reconstruction algorithms for DECT, there still exist two main problems: 1) For polyenergetic X-ray source, the tube spectrum needed in reconstruction is not always available. 2) The reconstructed image of DECT is very sensitive to noise which demands special noise suppression strategy in reconstruction algorithm design. In this paper, we propose a novel method for DECT reconstruction that reconstructs tube spectrum from projection data and suppresses image noise by introducing l1-norm based regularization into statistical reconstruction for polychromatic DECT. The contribution of this work is twofold. 1) A three parameters model is devised to represent spectrum of ployenergetic X-ray source. And the parameters can be estimated from projection data by solving an optimization problem. 2) With the estimated tube spectrum, we propose a computation framework of l1-norm regularization based statistical iterative reconstruction for polychromatic DECT. Simulation experiments with two phantoms were conducted to evaluate the proposed method. Experimental results demonstrate the accuracy and robustness of the spectrum model in terms of that comparable reconstruction image quality can be achieved with the estimated and ideal spectrum, and validate that the proposed method works with attractive performance in terms of accuracy of reconstructed image. The root mean square error (RMSE) between the reconstructed image and the ground truth image are 7.648 × 10-4 and 2.687 x 10-4 for the two phantoms, respectively.

  6. Programming in C at NMFECC (National Magnetic Fusion Energy Computing Center): A practical guide

    SciTech Connect

    Haney, S.W.; Crotinger, J.A.

    1989-07-26

    Despite its popularity elsewhere, C has not been extensively used for scientific programming on supercomputers. There are a number of reasons for this but perhaps the most compelling has been the lack of C compilers. However, this situation has recently begun to change at the National Magnetic Fusion Energy Computing Center (NMFECC) where two C development platforms --- the Hybrid C Compiler (HCC) written at the Livermore Computer Center and the Portable C Compiler (CC version 4.1) distributed by Cray Research, Inc. (CRI) --- have become available for use. These compilers produce object code for all of the Cray models at NMFECC and, in addition, possess good scalar optimization capabilities along with rudimentary vectorization capabilities. With the advent of the Cray C compilers, it is possible to consider physics code development in C at NMFECC. However, when one actually attempts to pursue this goal, one is quickly faced with a number of practical problems. For instance, How do I compile, link, and debug C codes What special features of C are useful to me as a scientific programmer Are there things I currently can't do in C programs How do I interface my C program to existing Fortran code Can I make use of the Basis code development system from C Over the last three years we have incorporated C into numerous physics codes written at NMFECC and, in the course of this work, we have had to develop solutions to all of the above problems. This turned out to be a surprisingly frustrating and time-consuming venture requiring some rather subtle techniques and hacks. This guide is an attempt to document these techniques.

  7. Computational model of in vivo human energy metabolism during semi-starvation and re-feeding

    PubMed Central

    Hall, Kevin D.

    2008-01-01

    Changes of body weight and composition are the result of complex interactions among metabolic fluxes contributing to macronutrient balances. To better understand these interactions, a mathematical model was constructed that used the measured dietary macronutrient intake during semi-starvation and re-feeding as model inputs and computed whole-body energy expenditure, de novo lipogenesis, gluconeogenesis, as well as turnover and oxidation of carbohydrate, fat and protein. Published in vivo human data provided the basis for the model components which were integrated by fitting a few unknown parameters to the classic Minnesota human starvation experiment. The model simulated the measured body weight and fat mass changes during semi-starvation and re-feeding and predicted the unmeasured metabolic fluxes underlying the body composition changes. The resting metabolic rate matched the experimental measurements and required a model of adaptive thermogenesis. Re-feeding caused an elevation of de novo lipogenesis which, along with increased fat intake, resulted in a rapid repletion and overshoot of body fat. By continuing the computer simulation with the pre-starvation diet and physical activity, the original body weight and composition was eventually restored, but body fat mass was predicted to take more than one additional year to return to within 5% of its original value. The model was validated by simulating a recently published short-term caloric restriction experiment without changing the model parameters. The predicted changes of body weight, fat mass, resting metabolic rate, and nitrogen balance matched the experimental measurements thereby providing support for the validity of the model. PMID:16449298

  8. High Energy Physics Forum for Computational Excellence: Working Group Reports (I. Applications Software II. Software Libraries and Tools III. Systems)

    SciTech Connect

    Habib, Salman; Roser, Robert

    2015-10-28

    Computing plays an essential role in all aspects of high energy physics. As computational technology evolves rapidly in new directions, and data throughput and volume continue to follow a steep trend-line, it is important for the HEP community to develop an effective response to a series of expected challenges. In order to help shape the desired response, the HEP Forum for Computational Excellence (HEP-FCE) initiated a roadmap planning activity with two key overlapping drivers -- 1) software effectiveness, and 2) infrastructure and expertise advancement. The HEP-FCE formed three working groups, 1) Applications Software, 2) Software Libraries and Tools, and 3) Systems (including systems software), to provide an overview of the current status of HEP computing and to present findings and opportunities for the desired HEP computational roadmap. The final versions of the reports are combined in this document, and are presented along with introductory material.

  9. Independent-Trajectory Thermodynamic Integration: a practical guide to protein-drug binding free energy calculations using distributed computing.

    PubMed

    Lawrenz, Morgan; Baron, Riccardo; Wang, Yi; McCammon, J Andrew

    2012-01-01

    The Independent-Trajectory Thermodynamic Integration (IT-TI) approach for free energy calculation with distributed computing is described. IT-TI utilizes diverse conformational sampling obtained from multiple, independent simulations to obtain more reliable free energy estimates compared to single TI predictions. The latter may significantly under- or over-estimate the binding free energy due to finite sampling. We exemplify the advantages of the IT-TI approach using two distinct cases of protein-ligand binding. In both cases, IT-TI yields distributions of absolute binding free energy estimates that are remarkably centered on the target experimental values. Alternative protocols for the practical and general application of IT-TI calculations are investigated. We highlight a protocol that maximizes predictive power and computational efficiency.

  10. A comparative study of methods to compute the free energy of an ordered assembly by molecular simulation.

    PubMed

    Moustafa, Sabry G; Schultz, Andrew J; Kofke, David A

    2013-08-28

    We present a comparative study of methods to compute the absolute free energy of a crystalline assembly of hard particles by molecular simulation. We consider all combinations of three choices defining the methodology: (1) the reference system: Einstein crystal (EC), interacting harmonic (IH), or r(-12) soft spheres (SS); (2) the integration path: Frenkel-Ladd (FL) or penetrable ramp (PR); and (3) the free-energy method: overlap-sampling free-energy perturbation (OS) or thermodynamic integration (TI). We apply the methods to FCC hard spheres at the melting state. The study shows that, in the best cases, OS and TI are roughly equivalent in efficiency, with a slight advantage to TI. We also examine the multistate Bennett acceptance ratio method, and find that it offers no advantage for this particular application. The PR path shows advantage in general over FL, providing results of the same precision with 2-9 times less computation, depending on the choice of a common reference. The best combination for the FL path is TI+EC, which is how the FL method is usually implemented. For the PR path, the SS system (with either TI or OS) proves to be most effective; it gives equivalent precision to TI+FL+EC with about 6 times less computation (or 12 times less, if discounting the computational effort required to establish the SS reference free energy). Both the SS and IH references show great advantage in capturing finite-size effects, providing a variation in free-energy difference with system size that is about 10 times less than EC. This result further confirms previous work for soft-particle crystals, and suggests that free-energy calculations for a structured assembly be performed using a hybrid method, in which the finite-system free-energy difference is added to the extrapolated (1/N→0) absolute free energy of the reference system, to obtain a result that is nearly independent of system size.

  11. Econometrically calibrated computable general equilibrium models: Applications to the analysis of energy and climate politics

    NASA Astrophysics Data System (ADS)

    Schu, Kathryn L.

    Economy-energy-environment models are the mainstay of economic assessments of policies to reduce carbon dioxide (CO2) emissions, yet their empirical basis is often criticized as being weak. This thesis addresses these limitations by constructing econometrically calibrated models in two policy areas. The first is a 35-sector computable general equilibrium (CGE) model of the U.S. economy which analyzes the uncertain impacts of CO2 emission abatement. Econometric modeling of sectors' nested constant elasticity of substitution (CES) cost functions based on a 45-year price-quantity dataset yields estimates of capital-labor-energy-material input substitution elasticities and biases of technical change that are incorporated into the CGE model. I use the estimated standard errors and variance-covariance matrices to construct the joint distribution of the parameters of the economy's supply side, which I sample to perform Monte Carlo baseline and counterfactual runs of the model. The resulting probabilistic abatement cost estimates highlight the importance of the uncertainty in baseline emissions growth. The second model is an equilibrium simulation of the market for new vehicles which I use to assess the response of vehicle prices, sales and mileage to CO2 taxes and increased corporate average fuel economy (CAFE) standards. I specify an econometric model of a representative consumer's vehicle preferences using a nested CES expenditure function which incorporates mileage and other characteristics in addition to prices, and develop a novel calibration algorithm to link this structure to vehicle model supplies by manufacturers engaged in Bertrand competition. CO2 taxes' effects on gasoline prices reduce vehicle sales and manufacturers' profits if vehicles' mileage is fixed, but these losses shrink once mileage can be adjusted. Accelerated CAFE standards induce manufacturers to pay fines for noncompliance rather than incur the higher costs of radical mileage improvements

  12. Tophaceous Gout in an Anorectic Patient Visualized by Dual Energy Computed Tomography (DECT).

    PubMed

    Christensen, Heidi Dahl; Sheta, Hussam Mahmoud; Morillon, Melanie Birger; Hansen, Inger Marie Jensen

    2016-07-15

    BACKGROUND Gout is characterized by deposition of uric acid crystals (monosodium urate) in tissues and fluids. This can cause acute inflammatory arthritis. The 2015 ACR/EULAR criteria for the diagnosis of gout include dual energy computed tomography (DECT)-demonstrated monosodium urate crystals as a new criterion. DECT is a spectral decomposition that permits recognition of different types of tissues based on their characteristic energy-dependent photon attenuation. A positive scan is defined as the presence of urate at articular or periarticular sites. CASE REPORT We describe a 51-year-old woman known to have anorexia nervosa. During our clinical examination, we detected plenty of tophi on both hands, but no swollen joints. The diagnosis of gout was made by visualizing crystals in a biopsy from a tophus. The first line of treatment was allopurinol, the second line was rasburicase, and the current treatment is febuxostat 80 mg/day, allopurinol 300 mg twice a day, and colchicine 0.5 mg twice a day. The patient has unchanged arthralgia and the size and number of tophi remain the same as before treatment in spite of active treatment for 3 years. Previously the patient had problems with adherence, but now she claims that she follows the proposed treatment. The last plasma urate (P-urate) was 0.57 mmol/L. Following two years of treatment, DECT of hands visualized monosodium urate crystal deposits in the tophi, as seen on the clinical photos, but also crystals in relation to the tendons and soft tissue.  CONCLUSIONS DECT is an imaging modality useful to assess urate crystal deposits at diagnosis of gout and could be considered during treatment evaluation. Lack of adherence to treatment should be considered when P-urate values vary significantly and when DECT scans over years persistently visualize monosodium urate crystals.

  13. Orientation and the Young Orienteer

    NASA Astrophysics Data System (ADS)

    Walsh, S. E.; Martland, J. R.

    Orientation within orienteering is dependent on the use of two basic strategies; that is, either a compass or Magnetic-North-based strategy, which relies on the use of one set of information; or the use of a map and landmark-based strategy which relies on the use of at least two sets of information. Walsh and found that, when given the choice, young children use the compass-based strategy when following complex potentially disorientating routes.The efficacy of these two basic orientation strategies was investigated within three different orienteering environments: (1) a familiar known environment; (2) a familiar unknown environment and (3) an unfamiliar unknown environment.Subjects, age range from 9 to 10think aloud particularly the introduction of basic skills to young performers. They support the argument that is essential to introduce the map and compass simultaneously and that relocation and orientation skills should be coached concurrently.

  14. Passive orientation apparatus

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Martinez, Michael A.

    2001-01-01

    An apparatus that can return a payload to a known orientation after unknown motion, without requiring external power or complex mechanical systems. The apparatus comprises a faceted cage that causes the system to rest in a stable position and orientation after arbitrary motion. A gimbal is mounted with the faceted cage and holds the payload, allowing the payload to move relative to the stable faceted cage. The payload is thereby placed in a known orientation by the interaction of gravity with the geometry of the faceted cage, the mass of the system, and the motion of the payload and gimbal. No additional energy, control, or mechanical actuation is required. The apparatus is suitable for use in applications requiring positioning of a payload to a known orientation after arbitrary or uncontrolled motion, including remote sensing and mobile robot applications.

  15. Developmental dysplasia of the hip: A computational biomechanical model of the path of least energy for closed reduction.

    PubMed

    Zwawi, Mohammed A; Moslehy, Faissal A; Rose, Christopher; Huayamave, Victor; Kassab, Alain J; Divo, Eduardo; Jones, Brendan J; Price, Charles T

    2016-10-20

    This study utilized a computational biomechanical model and applied the least energy path principle to investigate two pathways for closed reduction of high grade infantile hip dislocation. The principle of least energy when applied to moving the femoral head from an initial to a final position considers all possible paths that connect them and identifies the path of least resistance. Clinical reports of severe hip dysplasia have concluded that reduction of the femoral head into the acetabulum may occur by a direct pathway over the posterior rim of the acetabulum when using the Pavlik harness, or by an indirect pathway with reduction through the acetabular notch when using the modified Hoffman-Daimler method. This computational study also compared the energy requirements for both pathways. The anatomical and muscular aspects of the model were derived using a combination of MRI and OpenSim data. Results of this study indicate that the path of least energy closely approximates the indirect pathway of the modified Hoffman-Daimler method. The direct pathway over the posterior rim of the acetabulum required more energy for reduction. This biomechanical analysis confirms the clinical observations of the two pathways for closed reduction of severe hip dysplasia. The path of least energy closely approximated the modified Hoffman-Daimler method. Further study of the modified Hoffman-Daimler method for reduction of severe hip dysplasia may be warranted based on this computational biomechanical analysis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  16. PREFACE: International Conference on Computing in High Energy and Nuclear Physics (CHEP 2012)

    NASA Astrophysics Data System (ADS)

    Ernst, Michael; Düllmann, Dirk; Rind, Ofer; Wong, Tony

    2012-12-01

    The International Conference on Computing in High Energy and Nuclear Physics (CHEP) was held at New York University on 21- 25 May 2012. CHEP is a major series of international conferences for physicists and computing professionals from the High Energy and Nuclear Physics community and related scientific and technical fields. The CHEP conference provides a forum to exchange information on computing progress and needs for the community, and to review recent, ongoing and future activities. CHEP conferences are held at roughly 18-month intervals, alternating between Europe, Asia, the Americas and other parts of the world. Recent CHEP conferences have been held in Taipei, Taiwan (2010); Prague, Czech Republic (2009); Victoria, Canada (2007); Mumbai, India (2006); Interlaken, Switzerland (2004); San Diego, United States (2003); Beijing, China (2001); Padova, Italy (2000). CHEP 2012 was organized by Brookhaven National Laboratory (BNL) and co-sponsored by New York University. The organizational structure for CHEP consists of an International Advisory Committee (IAC) which sets the overall themes of the conference, a Program Organizing Committee (POC) that oversees the program content, and a Local Organizing Committee (LOC) that is responsible for local arrangements (lodging, transportation and social events) and conference logistics (registration, program scheduling, conference site selection and conference proceedings). There were over 500 attendees with a program that included plenary sessions of invited speakers, a number of parallel sessions comprising around 125 oral and 425 poster presentations and industrial exhibitions. We thank all the presenters for the excellent scientific content of their contributions to the conference. Conference tracks covered topics on Online Computing, Event Processing, Distributed Processing and Analysis on Grids and Clouds, Computer Facilities, Production Grids and Networking, Software Engineering, Data Stores and Databases and

  17. Liquid rocket combustion computer model with distributed energy release. DER computer program documentation and user's guide, volume 1

    NASA Technical Reports Server (NTRS)

    Combs, L. P.

    1974-01-01

    A computer program for analyzing rocket engine performance was developed. The program is concerned with the formation, distribution, flow, and combustion of liquid sprays and combustion product gases in conventional rocket combustion chambers. The capabilities of the program to determine the combustion characteristics of the rocket engine are described. Sample data code sheets show the correct sequence and formats for variable values and include notes concerning options to bypass the input of certain data. A seperate list defines the variables and indicates their required dimensions.

  18. Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines

    PubMed Central

    Seddiqzai, Meriam; Dahmen, Tobias; Sure, Rebecca

    2013-01-01

    Summary The intramolecular radical addition to aniline derivatives was investigated by DFT calculations. The computational methods were benchmarked by comparing the calculated values of the rate constant for the 5-exo cyclization of the hexenyl radical with the experimental values. The dispersion-corrected PW6B95-D3 functional provided very good results with deviations for the free activation barrier compared to the experimental values of only about 0.5 kcal mol−1 and was therefore employed in further calculations. Corrections for intramolecular London dispersion and solvation effects in the quantum chemical treatment are essential to obtain consistent and accurate theoretical data. For the investigated radical addition reaction it turned out that the polarity of the molecules is important and that a combination of electrophilic radicals with preferably nucleophilic arenes results in the highest rate constants. This is opposite to the Minisci reaction where the radical acts as nucleophile and the arene as electrophile. The substitution at the N-atom of the aniline is crucial. Methyl substitution leads to slower addition than phenyl substitution. Carbamates as substituents are suitable only when the radical center is not too electrophilic. No correlations between free reaction barriers and energies (ΔG ‡ and ΔG R) are found. Addition reactions leading to indanes or dihydrobenzofurans are too slow to be useful synthetically. PMID:24062821

  19. Experimental and Computational Investigations of Phase Change Thermal Energy Storage Canisters

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Kerslake, Thomas; Sokolov, Pavel; Tolbert, Carol

    1996-01-01

    Two sets of experimental data are examined in this paper, ground and space experiments, for cylindrical canisters with thermal energy storage applications. A 2-D computational model was developed for unsteady heat transfer (conduction and radiation) with phase-change. The radiation heat transfer employed a finite volume method. The following was found in this study: (1) Ground Experiments: the convection heat transfer is equally important to that of the radiation heat transfer; radiation heat transfer in the liquid is found to be more significant than that in the void; including the radiation heat transfer in the liquid resulted in lower temperatures (about 15 K) and increased the melting time (about 10 min.); generally, most of the heat flow takes place in the radial direction. (2) Space Experiments: radiation heat transfer in the void is found to be more significant than that in the liquid (exactly the opposite to the Ground Experiments); accordingly, the location and size of the void affects the performance considerably; including the radiation heat transfer in the void resulted in lower temperatures (about 40 K).

  20. Experimental, Theoretical and Computational Studies of Plasma-Based Concepts for Future High Energy Accelerators

    SciTech Connect

    Joshi, Chan; Mori, W.

    2013-10-21

    This is the final report on the DOE grant number DE-FG02-92ER40727 titled, “Experimental, Theoretical and Computational Studies of Plasma-Based Concepts for Future High Energy Accelerators.” During this grant period the UCLA program on Advanced Plasma Based Accelerators, headed by Professor C. Joshi has made many key scientific advances and trained a generation of students, many of whom have stayed in this research field and even started research programs of their own. In this final report however, we will focus on the last three years of the grant and report on the scientific progress made in each of the four tasks listed under this grant. Four tasks are focused on: Plasma Wakefield Accelerator Research at FACET, SLAC National Accelerator Laboratory, In House Research at UCLA’s Neptune and 20 TW Laser Laboratories, Laser-Wakefield Acceleration (LWFA) in Self Guided Regime: Experiments at the Callisto Laser at LLNL, and Theory and Simulations. Major scientific results have been obtained in each of the four tasks described in this report. These have led to publications in the prestigious scientific journals, graduation and continued training of high quality Ph.D. level students and have kept the U.S. at the forefront of plasma-based accelerators research field.

  1. Measurement of body composition in cats using computed tomography and dual energy X-ray absorptiometry.

    PubMed

    Buelund, Lene E; Nielsen, Dorte H; McEvoy, Fintan J; Svalastoga, Eiliv L; Bjornvad, Charlotte R

    2011-01-01

    Dual energy X-ray absorptiometry (DEXA) is a reference method for assessing body composition but is seldom `accessible in veterinary settings. Computed tomography (CT) can provide similar body composition estimates and we propose that it can be used in body composition studies in animals. We compared CT and DEXA data from 73 healthy adult neutered domestic cats. Three approaches for measuring adipose tissue percentage from full-body CT scans were explored. By examining the frequency distribution of voxels by Hounsfield unit (HU) value, it is possible to calculate a fat index (Fat%) that is in close agreement with the fat percentages obtained from DEXA scans. Fat% values obtained by the best of the methods had a mean difference of 0.96% (95% confidence interval 0.33-1.59%) from the DEXA results. Fat% obtained by the other two methods were characterized by good correlation but poor agreement and in one of the methods, the difference between the values from the two modalities was proportional to their mean. By using CT, it is possible to obtain body composition estimates that are in close agreement with those available using DEXA. While the significance of individual Fat% measurements obtained from CT can be difficult to interpret and to compare between centers, CT can contribute to research studies concerned either with nutrition or with obesity-related disorders.

  2. Role of Dual Energy Computed Tomography Imaging in the Diagnosis of Gout

    PubMed Central

    Sehra, Shiv T; Anand, Suneesh; Stallings, Gary W.; Danve, Abhijeet

    2017-01-01

    Gout is a well-known inflammatory arthritis and affects four percent of the United States population. It results from the deposition of uric acid crystals in joints, tendons, bursae, and other surrounding tissues. Prevalence of gout has increased in the recent decade. Gout is usually seen in conjunction with other chronic comorbid conditions like cardiac disease, metabolic syndrome, and renal disease. The diagnosis of this inflammatory arthritis is confirmed by visualization of monosodium urate (MSU) crystals in the synovial fluid. Though synovial fluid aspiration is the standard of care, it is often deferred because of inaccessibility of small joints, patient assessment during intercritical period, or procedural inexperience in a primary care office. Dual energy computed tomography (DECT) is a relatively new imaging modality which shows great promise in the diagnosis of gout. It is a good noninvasive alternative to synovial fluid aspiration. DECT is increasingly useful in diagnosing cases of gout where synovial fluid fails to demonstrate monosodium urate crystals. In this article, we will review the mechanism, types, advantages, and disadvantages of DECT. PMID:28229032

  3. Role of Dual Energy Computed Tomography Imaging in the Diagnosis of Gout.

    PubMed

    Jayakumar, Divya; Sehra, Shiv T; Anand, Suneesh; Stallings, Gary W; Danve, Abhijeet

    2017-01-20

    Gout is a well-known inflammatory arthritis and affects four percent of the United States population. It results from the deposition of uric acid crystals in joints, tendons, bursae, and other surrounding tissues. Prevalence of gout has increased in the recent decade. Gout is usually seen in conjunction with other chronic comorbid conditions like cardiac disease, metabolic syndrome, and renal disease. The diagnosis of this inflammatory arthritis is confirmed by visualization of monosodium urate (MSU) crystals in the synovial fluid. Though synovial fluid aspiration is the standard of care, it is often deferred because of inaccessibility of small joints, patient assessment during intercritical period, or procedural inexperience in a primary care office. Dual energy computed tomography (DECT) is a relatively new imaging modality which shows great promise in the diagnosis of gout. It is a good noninvasive alternative to synovial fluid aspiration. DECT is increasingly useful in diagnosing cases of gout where synovial fluid fails to demonstrate monosodium urate crystals. In this article, we will review the mechanism, types, advantages, and disadvantages of DECT.

  4. Energy conserving numerical methods for the computation of complex vortical flows

    NASA Astrophysics Data System (ADS)

    Allaneau, Yves

    One of the original goals of this thesis was to develop numerical tools to help with the design of micro air vehicles. Micro Air Vehicles (MAVs) are small flying devices of only a few inches in wing span. Some people consider that as their size becomes smaller and smaller, it would be increasingly more difficult to keep all the classical control surfaces such as the rudders, the ailerons and the usual propellers. Over the years, scientists took inspiration from nature. Birds, by flapping and deforming their wings, are capable of accurate attitude control and are able to generate propulsion. However, the biomimicry design has its own limitations and it is difficult to place a hummingbird in a wind tunnel to study precisely the motion of its wings. Our approach was to use numerical methods to tackle this challenging problem. In order to precisely evaluate the lift and drag generated by the wings, one needs to be able to capture with high fidelity the extremely complex vortical flow produced in the wake. This requires a numerical method that is stable yet not too dissipative, so that the vortices do not get diffused in an unphysical way. We solved this problem by developing a new Discontinuous Galerkin scheme that, in addition to conserving mass, momentum and total energy locally, also preserves kinetic energy globally. This property greatly improves the stability of the simulations, especially in the special case p=0 when the approximation polynomials are taken to be piecewise constant (we recover a finite volume scheme). In addition to needing an adequate numerical scheme, a high fidelity solution requires many degrees of freedom in the computations to represent the flow field. The size of the smallest eddies in the flow is given by the Kolmogoroff scale. Capturing these eddies requires a mesh counting in the order of Re³ cells, where Re is the Reynolds number of the flow. We show that under-resolving the system, to a certain extent, is acceptable. However our

  5. High-energy transmission Laue micro-beam X-ray diffraction: a probe for intra-granular lattice orientation and elastic strain in thicker samples.

    PubMed

    Hofmann, Felix; Song, Xu; Abbey, Brian; Jun, Tea-Sung; Korsunsky, Alexander M

    2012-05-01

    An understanding of the mechanical response of modern engineering alloys to complex loading conditions is essential for the design of load-bearing components in high-performance safety-critical aerospace applications. A detailed knowledge of how material behaviour is modified by fatigue and the ability to predict failure reliably are vital for enhanced component performance. Unlike macroscopic bulk properties (e.g. stiffness, yield stress, etc.) that depend on the average behaviour of many grains, material failure is governed by `weakest link'-type mechanisms. It is strongly dependent on the anisotropic single-crystal elastic-plastic behaviour, local morphology and microstructure, and grain-to-grain interactions. For the development and validation of models that capture these complex phenomena, the ability to probe deformation behaviour at the micro-scale is key. The diffraction of highly penetrating synchrotron X-rays is well suited to this purpose and micro-beam Laue diffraction is a particularly powerful tool that has emerged in recent years. Typically it uses photon energies of 5-25 keV, limiting penetration into the material, so that only thin samples or near-surface regions can be studied. In this paper the development of high-energy transmission Laue (HETL) micro-beam X-ray diffraction is described, extending the micro-beam Laue technique to significantly higher photon energies (50-150 keV). It allows the probing of thicker sample sections, with the potential for grain-level characterization of real engineering components. The new HETL technique is used to study the deformation behaviour of individual grains in a large-grained polycrystalline nickel sample during in situ tensile loading. Refinement of the Laue diffraction patterns yields lattice orientations and qualitative information about elastic strains. After deformation, bands of high lattice misorientation can be identified in the sample. Orientation spread within individual scattering volumes is

  6. De novo Cloning and Annotation of Genes Associated with Immunity, Detoxification and Energy Metabolism from the Fat Body of the Oriental Fruit Fly, Bactrocera dorsalis

    PubMed Central

    Yang, Wen-Jia; Yuan, Guo-Rui; Cong, Lin; Xie, Yi-Fei; Wang, Jin-Jun

    2014-01-01

    The oriental fruit fly, Bactrocera dorsalis, is a destructive pest in tropical and subtropical areas. In this study, we performed transcriptome-wide analysis of the fat body of B. dorsalis and obtained more than 59 million sequencing reads, which were assembled into 27,787 unigenes with an average length of 591 bp. Among them, 17,442 (62.8%) unigenes matched known proteins in the NCBI database. The assembled sequences were further annotated with gene ontology, cluster of orthologous group terms, and Kyoto encyclopedia of genes and genomes. In depth analysis was performed to identify genes putatively involved in immunity, detoxification, and energy metabolism. Many new genes were identified including serpins, peptidoglycan recognition proteins and defensins, which were potentially linked to immune defense. Many detoxification genes were identified, including cytochrome P450s, glutathione S-transferases and ATP-binding cassette (ABC) transporters. Many new transcripts possibly involved in energy metabolism, including fatty acid desaturases, lipases, alpha amylases, and trehalose-6-phosphate synthases, were identified. Moreover, we randomly selected some genes to examine their expression patterns in different tissues by quantitative real-time PCR, which indicated that some genes exhibited fat body-specific expression in B. dorsalis. The identification of a numerous transcripts in the fat body of B. dorsalis laid the foundation for future studies on the functions of these genes. PMID:24710118

  7. High confinement and high density with stationary plasma energy and strong edge radiation cooling in the upgraded Torus Experiment for Technology Oriented Research (TEXTOR-94)

    SciTech Connect

    Messiaen, A.M.; Ongena, J.; Unterberg, B.; Boedo, J.; Fuchs, G.; Jaspers, R.; Konen, L.; Koslowski, H.R.; Mank, G.; Rapp, J.; Samm, U.; Vandenplas, P.E.; Van Oost, G.; Van Wassenhove, G.; Waidmann, G.; Weynants, R.R.; Wolf, G.H.; Bertschinger, G.; Bonheure, G.; Brix, M.; Dumortier, P.; Durodie, F.; Finken, K.H.; Giesen, B.; Hillis, D.; Hutteman, P.; Koch, R.; Kramer-Flecken, A.; Lyssoivan, A.; Mertens, P.; Pospieszczyk, A.; Post-Zwicker, A.; Sauer, M.; Schweer, B.; Schwelberger, J.; Telesca, G.; Tokar, M.Z.; Uhlemann, R.; Vervier, M.; Winter, J. ||||

    1997-05-01

    An overview of the results obtained so far for the radiative I-mode regime on the upgraded Torus Experiment for Technology Oriented Research (TEXTOR-94) [{ital Proceedings of the 16th IEEE Symposium on Fusion Engineering} (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 1995), Vol. 1, p. 470] is given. This regime is obtained under quasistationary conditions with edge neon seeding in a pumped limiter tokamak with circular cross section. It combines high confinement and high {beta} (up to a normalized beta, {beta}{sub n}=2) with low edge q values (down to q{sub a}=2.8) and high density even above the Greenwald limit together with dominant edge radiative heat exhaust, and therefore shows promise for the future of fusion research. Bulk and edge properties of these discharges are described, and a detailed account is given of the energy and particle confinement and their scaling. Energy confinement scales linearly with density as for the nonsaturated Ohmic Neo-Alcator scaling, but the usual degradation with total power remains. No deleterious effects of the neon seeding on fusion reactivity and plasma stability have been observed. {copyright} {ital 1997 American Institute of Physics.}

  8. DESAE (Dynamic Energy System- Atomic Energy): Integrated Computer Model for Performing Global Analysis in INPRO Assessment Studies

    SciTech Connect

    Tsibulskiy, V.; Subbotin, S.; Khoroshev, M.; Depisch, F.

    2006-07-01

    The Agency's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) was established to help to ensure that nuclear energy is available to contribute, in a sustainable manner, to the energy needs in the 21. century. In 2005, its membership continued to grow, with Ukraine and United States of America becoming additional members, and total INPRO membership now stands at 24. (authors)

  9. Considerations of blood properties, outlet boundary conditions and energy loss approaches in computational fluid dynamics modeling.

    PubMed

    Moon, Ji Young; Suh, Dae Chul; Lee, Yong Sang; Kim, Young Woo; Lee, Joon Sang

    2014-02-01

    Despite recent development of computational fluid dynamics (CFD) research, analysis of computational fluid dynamics of cerebral vessels has several limitations. Although blood is a non-Newtonian fluid, velocity and pressure fields were computed under the assumptions of incompressible, laminar, steady-state flows and Newtonian fluid dynamics. The pulsatile nature of blood flow is not properly applied in inlet and outlet boundaries. Therefore, we present these technical limitations and discuss the possible solution by comparing the theoretical and computational studies.

  10. An Experiment in the Use of Computer-Based Education to Teach Energy Considerations in Architectural Design.

    ERIC Educational Resources Information Center

    Arumi, Francisco N.

    Computer programs capable of describing the thermal behavior of buildings are used to help architectural students understand environmental systems. The Numerical Simulation Laboratory at the Architectural School of the University of Texas at Austin was developed to provide the necessary software capable of simulating the energy transactions…

  11. Analyzing Orientations

    NASA Astrophysics Data System (ADS)

    Ruggles, Clive L. N.

    Archaeoastronomical field survey typically involves the measurement of structural orientations (i.e., orientations along and between built structures) in relation to the visible landscape and particularly the surrounding horizon. This chapter focuses on the process of analyzing the astronomical potential of oriented structures, whether in the field or as a desktop appraisal, with the aim of establishing the archaeoastronomical "facts". It does not address questions of data selection (see instead Chap. 25, "Best Practice for Evaluating the Astronomical Significance of Archaeological Sites", 10.1007/978-1-4614-6141-8_25) or interpretation (see Chap. 24, "Nature and Analysis of Material Evidence Relevant to Archaeoastronomy", 10.1007/978-1-4614-6141-8_22). The main necessity is to determine the azimuth, horizon altitude, and declination in the direction "indicated" by any structural orientation. Normally, there are a range of possibilities, reflecting the various errors and uncertainties in estimating the intended (or, at least, the constructed) orientation, and in more formal approaches an attempt is made to assign a probability distribution extending over a spread of declinations. These probability distributions can then be cumulated in order to visualize and analyze the combined data from several orientations, so as to identify any consistent astronomical associations that can then be correlated with the declinations of particular astronomical objects or phenomena at any era in the past. The whole process raises various procedural and methodological issues and does not proceed in isolation from the consideration of corroborative data, which is essential in order to develop viable cultural interpretations.

  12. Exponential vanishing of the ground-state gap of the quantum random energy model via adiabatic quantum computing

    SciTech Connect

    Adame, J.; Warzel, S.

    2015-11-15

    In this note, we use ideas of Farhi et al. [Int. J. Quantum. Inf. 6, 503 (2008) and Quantum Inf. Comput. 11, 840 (2011)] who link a lower bound on the run time of their quantum adiabatic search algorithm to an upper bound on the energy gap above the ground-state of the generators of this algorithm. We apply these ideas to the quantum random energy model (QREM). Our main result is a simple proof of the conjectured exponential vanishing of the energy gap of the QREM.

  13. Grain Boundary Plane Orientation Fundamental Zones and Structure-Property Relationships.

    PubMed

    Homer, Eric R; Patala, Srikanth; Priedeman, Jonathan L

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.

  14. Grain Boundary Plane Orientation Fundamental Zones and Structure-Property Relationships

    PubMed Central

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-01-01

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries. PMID:26498715

  15. Grain boundary plane orientation fundamental zones and structure-property relationships

    SciTech Connect

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.

  16. Grain boundary plane orientation fundamental zones and structure-property relationships

    DOE PAGES

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to themore » strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.« less

  17. Accurate computations of the structures and binding energies of the imidazole⋯benzene and pyrrole⋯benzene complexes

    NASA Astrophysics Data System (ADS)

    Ahnen, Sandra; Hehn, Anna-Sophia; Vogiatzis, Konstantinos D.; Trachsel, Maria A.; Leutwyler, Samuel; Klopper, Wim

    2014-09-01

    Using explicitly-correlated coupled-cluster theory with single and double excitations, the intermolecular distances and interaction energies of the T-shaped imidazole⋯benzene and pyrrole⋯benzene complexes have been computed in a large augmented correlation-consistent quadruple-zeta basis set, adding also corrections for connected triple excitations and remaining basis-set-superposition errors. The results of these computations are used to assess other methods such as Møller-Plesset perturbation theory (MP2), spin-component-scaled MP2 theory, dispersion-weighted MP2 theory, interference-corrected explicitly-correlated MP2 theory, dispersion-corrected double-hybrid density-functional theory (DFT), DFT-based symmetry-adapted perturbation theory, the random-phase approximation, explicitly-correlated ring-coupled-cluster-doubles theory, and double-hybrid DFT with a correlation energy computed in the random-phase approximation.

  18. An Analysis Framework for Investigating the Trade-offs Between System Performance and Energy Consumption in a Heterogeneous Computing Environment

    SciTech Connect

    Friese, Ryan; Khemka, Bhavesh; Maciejewski, Anthony A; Siegel, Howard Jay; Koenig, Gregory A; Powers, Sarah S; Hilton, Marcia M; Rambharos, Rajendra; Okonski, Gene D; Poole, Stephen W

    2013-01-01

    Rising costs of energy consumption and an ongoing effort for increases in computing performance are leading to a significant need for energy-efficient computing. Before systems such as supercomputers, servers, and datacenters can begin operating in an energy-efficient manner, the energy consumption and performance characteristics of the system must be analyzed. In this paper, we provide an analysis framework that will allow a system administrator to investigate the tradeoffs between system energy consumption and utility earned by a system (as a measure of system performance). We model these trade-offs as a bi-objective resource allocation problem. We use a popular multi-objective genetic algorithm to construct Pareto fronts to illustrate how different resource allocations can cause a system to consume significantly different amounts of energy and earn different amounts of utility. We demonstrate our analysis framework using real data collected from online benchmarks, and further provide a method to create larger data sets that exhibit similar heterogeneity characteristics to real data sets. This analysis framework can provide system administrators with insight to make intelligent scheduling decisions based on the energy and utility needs of their systems.

  19. Validation of Methods for Computational Catalyst Design: Geometries, Structures, and Energies of Neutral and Charged Silver Clusters

    SciTech Connect

    Duanmu, Kaining; Truhlar, Donald G.

    2015-04-30

    We report a systematic study of small silver clusters, Agn, Agn+, and Agn–, n = 1–7. We studied all possible isomers of clusters with n = 5–7. We tested 42 exchange–correlation functionals, and we assess these functionals for their accuracy in three respects: geometries (quantitative prediction of internuclear distances), structures (the nature of the lowest-energy structure, for example, whether it is planar or nonplanar), and energies. We find that the ingredients of exchange–correlation functionals are indicators of their success in predicting geometries and structures: local exchange–correlation functionals are generally better than hybrid functionals for geometries; functionals depending on kinetic energy density are the best for predicting the lowest-energy isomer correctly, especially for predicting two-dimensional to three-dimenstional transitions correctly. The accuracy for energies is less sensitive to the ingredient list. Our findings could be useful for guiding the selection of methods for computational catalyst design.

  20. Only lower limb controlled interactive computer gaming enables an effective increase in energy expenditure.

    PubMed

    Jordan, Mark; Donne, Bernard; Fletcher, David

    2011-07-01

    Limited research documents if new and existing interactive computer gaming "exergaming" increase energy expenditure and cardio-respiratory costs comparable to common exercise modalities. To address this, healthy male volunteers (n = 15) completed six by 12-min test elements: PlayStation2 (PS2(hand)), Nintendo Wii boxing, walk at 5.6 km h(-1), cycle at 120 W, playing an adapted lower limb controlled PS2 (PS2(limb)) and run at 9.6 km h(-1). In addition, they played PS2(limb) for 30 min and performed an incremental treadmill test to exhaustion. Data were analysed using repeated measures ANOVA with post hoc Tukey tests, P < 0.05 inferred significance. PS2(limb) increased energy expenditure (EE) and post-exercise blood lactate (BLa) significantly higher (P < 0.001) than PS2(hand), Wii gaming or walking at 5.6 km h(-1) (EE: 30.3 ± 4.9 vs. 4.7 ± 1.1, 22.0 ± 6.1 and 17.9 ± 1.9 kJ h(-1) kg(-1); BLa: 2.4 ± 1.5 vs. 1.0 ± 0.3, 1.8 ± 0.8 and 0.9 ± 0.2 mmol L(-1)), playing the PS2(limb) raised mean EE over six times greater than PS2(hand). Mean fat and carbohydrate oxidation rates during the 9- to 12-min period playing the PS2(limb) were five and ten times greater than PS2(hand) (0.25 ± 0.10 vs. 0.05 ± 0.10, 1.69 ± 0.52 vs. 0.15 ± 0.14 g min(-1), respectively). PS2(limb) met ACSM guidelines for cardiovascular fitness; however, current Wii technology failed. In conclusion, gaming interactive technology must be adapted or designed to include the lower limbs in order to provide a significant exercise stimulus.

  1. Physics-based control-oriented modeling and robust feedback control of the plasma safety factor profile and stored energy dynamics in ITER

    NASA Astrophysics Data System (ADS)

    Barton, Justin E.; Besseghir, Karim; Lister, Jo; Schuster, Eugenio

    2015-11-01

    Many challenging plasma control problems still need to be addressed in order for the ITER plasma control system (PCS) to be able to maintain the plasma within a predefined operational space and optimize the plasma state evolution in the tokamak, which will greatly aid in the successful achievement of ITER’s goals. Firstly in this work, a general control-oriented, physics-based modeling approach is developed to obtain first-principles-driven (FPD) models of the plasma magnetic profile and stored energy evolutions valid for high performance, high confinement (H-mode) scenarios, with the goal of developing model-based closed-loop algorithms to control the safety factor profile (q profile) and stored energy evolutions in the tokamak. The FPD model is tailored to H-mode burning plasma scenarios in ITER by employing the DINA-CH & CRONOS free-boundary tokamak simulation code, and the FPD model’s prediction capabilities are demonstrated by comparing the prediction to data obtained from DINA-CH & CRONOS. Secondly, a model-based feedback control algorithm is designed to simultaneously track target q profile and stored energy evolutions in H-mode burning plasma scenarios in ITER by embedding the developed FPD model of the magnetic profile evolution into the control design process. The feedback controller is designed to ensure that the closed-loop system is robust to uncertainties in the electron density, electron temperature and plasma resistivity, and is tested in simulations with the developed FPD model. The effectiveness of the controller is demonstrated by first tracking nominal q profile and stored energy target evolutions, and then modulating the generated fusion power while maintaining the q profile in a stationary condition. In the process, many key practical issues for plasma profile control in ITER are investigated, which will be useful for the development of the ITER PCS that has recently been initiated. Some of the more pertinent investigated issues are the

  2. Generalized and efficient algorithm for computing multipole energies and gradients based on Cartesian tensors

    NASA Astrophysics Data System (ADS)

    Lin, Dejun

    2015-09-01

    Accurate representation of intermolecular forces has been the central task of classical atomic simulations, known as molecular mechanics. Recent advancements in molecular mechanics models have put forward the explicit representation of permanent and/or induced electric multipole (EMP) moments. The formulas developed so far to calculate EMP interactions tend to have complicated expressions, especially in Cartesian coordinates, which can only be applied to a specific kernel potential function. For example, one needs to develop a new formula each time a new kernel function is encountered. The complication of these formalisms arises from an intriguing and yet obscured mathematical relation between the kernel functions and the gradient operators. Here, I uncover this relation via rigorous derivation and find that the formula to calculate EMP interactions is basically invariant to the potential kernel functions as long as they are of the form f(r), i.e., any Green's function that depends on inter-particle distance. I provide an algorithm for efficient evaluation of EMP interaction energies, forces, and torques for any kernel f(r) up to any arbitrary rank of EMP moments in Cartesian coordinates. The working equations of this algorithm are essentially the same for any kernel f(r). Recently, a few recursive algorithms were proposed to calculate EMP interactions. Depending on the kernel functions, the algorithm here is about 4-16 times faster than these algorithms in terms of the required number of floating point operations and is much more memory efficient. I show that it is even faster than a theoretically ideal recursion scheme, i.e., one that requires 1 floating point multiplication and 1 addition per recursion step. This algorithm has a compact vector-based expression that is optimal for computer programming. The Cartesian nature of this algorithm makes it fit easily into modern molecular simulation packages as compared with spherical coordinate-based algorithms. A

  3. Generalized and efficient algorithm for computing multipole energies and gradients based on Cartesian tensors.

    PubMed

    Lin, Dejun

    2015-09-21

    Accurate representation of intermolecular forces has been the central task of classical atomic simulations, known as molecular mechanics. Recent advancements in molecular mechanics models have put forward the explicit representation of permanent and/or induced electric multipole (EMP) moments. The formulas developed so far to calculate EMP interactions tend to have complicated expressions, especially in Cartesian coordinates, which can only be applied to a specific kernel potential function. For example, one needs to develop a new formula each time a new kernel function is encountered. The complication of these formalisms arises from an intriguing and yet obscured mathematical relation between the kernel functions and the gradient operators. Here, I uncover this relation via rigorous derivation and find that the formula to calculate EMP interactions is basically invariant to the potential kernel functions as long as they are of the form f(r), i.e., any Green's function that depends on inter-particle distance. I provide an algorithm for efficient evaluation of EMP interaction energies, forces, and torques for any kernel f(r) up to any arbitrary rank of EMP moments in Cartesian coordinates. The working equations of this algorithm are essentially the same for any kernel f(r). Recently, a few recursive algorithms were proposed to calculate EMP interactions. Depending on the kernel functions, the algorithm here is about 4-16 times faster than these algorithms in terms of the required number of floating point operations and is much more memory efficient. I show that it is even faster than a theoretically ideal recursion scheme, i.e., one that requires 1 floating point multiplication and 1 addition per recursion step. This algorithm has a compact vector-based expression that is optimal for computer programming. The Cartesian nature of this algorithm makes it fit easily into modern molecular simulation packages as compared with spherical coordinate-based algorithms. A

  4. Large Energy Storage Density and High Thermal Stability in a Highly Textured (111)-Oriented Pb0.8Ba0.2ZrO3 Relaxor Thin Film with the Coexistence of Antiferroelectric and Ferroelectric Phases.

    PubMed

    Peng, Biaolin; Zhang, Qi; Li, Xing; Sun, Tieyu; Fan, Huiqing; Ke, Shanming; Ye, Mao; Wang, Yu; Lu, Wei; Niu, Hanben; Zeng, Xierong; Huang, Haitao

    2015-06-24

    A highly textured (111)-oriented Pb0.8Ba0.2ZrO3 (PBZ) relaxor thin film with the coexistence of antiferroelectric (AFE) and ferroelectric (FE) phases was prepared on a Pt/TiOx/SiO2/Si(100) substrate by using a sol-gel method. A large recoverable energy storage density of 40.18 J/cm(3) along with an efficiency of 64.1% was achieved at room temperature. Over a wide temperature range of 250 K (from room temperature to 523 K), the variation of the energy density is within 5%, indicating a high thermal stability. The high energy storage performance was endowed by a large dielectric breakdown strength, great relaxor dispersion, highly textured orientation, and the coexistence of FE and AFE phases. The PBZ thin film is believed to be an attractive material for applications in energy storage systems over a wide temperature range.

  5. Computer simulation of ultrafast processes of energy migration between C-phycocyanin chromophores of the blue-green algae Agmenellum quadruplicatum

    NASA Astrophysics Data System (ADS)

    Demidov, Andrey A.; Borisov, A. Y.

    1993-06-01

    Our work is devoted to the investigation of some problems of energy migration among C- phycocyanin (C-PC) chromophores: (a) determination of energy migration rates between chromophores at various aggregation states of C-PC; (b) determination of the main routes of energy transfer in the rods consisting of 2 - 4 C-PC hexamers; (c) whether the position and orientation of C-PC chromophores are optimal for energy migration; and (d) disclosing of the probability function of statistic of exciton jumping times between chromophores. We developed two approaches, both being based on the statistical analysis of consecutive exciton interchromophore jumps (microscopic level) during its 'life'. The macroscopic parameters are obtained via statistical averaging. The first is the Monte-Carlo method and the second one implies direct calculation of energy migration rates. The latter method has yielded detailed information about the rates of energy migration among chromophores of C-phycocyanin at various aggregation states and conditions of chromophore orientations.

  6. Interaction Entropy: A New Paradigm for Highly Efficient and Reliable Computation of Protein-Ligand Binding Free Energy.

    PubMed

    Duan, Lili; Liu, Xiao; Zhang, John Z H

    2016-05-04

    Efficient and reliable calculation of protein-ligand binding free energy is a grand challenge in computational biology and is of critical importance in drug design and many other molecular recognition problems. The main challenge lies in the calculation of entropic contribution to protein-ligand binding or interaction systems. In this report, we present a new interaction entropy method which is theoretically rigorous, computationally efficient, and numerically reliable for calculating entropic contribution to free energy in protein-ligand binding and other interaction processes. Drastically different from the widely employed but extremely expensive normal mode method for calculating entropy change in protein-ligand binding, the new method calculates the entropic component (interaction entropy or -TΔS) of the binding free energy directly from molecular dynamics simulation without any extra computational cost. Extensive study of over a dozen randomly selected protein-ligand binding systems demonstrated that this interaction entropy method is both computationally efficient and numerically reliable and is vastly superior to the standard normal mode approach. This interaction entropy paradigm introduces a novel and intuitive conceptual understanding of the entropic effect in protein-ligand binding and other general interaction systems as well as a practical method for highly efficient calculation of this effect.

  7. COMPUTER SIMULATIONS WITH EXPLICIT SOLVENT: Recent Progress in the Thermodynamic Decomposition of Free Energies and in Modeling Electrostatic Effects

    NASA Astrophysics Data System (ADS)

    Levy, Ronald M.; Gallicchio, Emilio

    1998-10-01

    This review focuses on recent progress in two areas in which computer simulations with explicit solvent are being applied: the thermodynamic decomposition of free energies, and modeling electrostatic effects. The computationally intensive nature of these simulations has been an obstacle to the systematic study of many problems in solvation thermodynamics, such as the decomposition of solvation and ligand binding free energies into component enthalpies and entropies. With the revolution in computer power continuing, these problems are ripe for study but require the judicious choice of algorithms and approximations. We provide a critical evaluation of several numerical approaches to the thermodynamic decomposition of free energies and summarize applications in the current literature. Progress in computer simulations with explicit solvent of charge perturbations in biomolecules was slow in the early 1990s because of the widespread use of truncated Coulomb potentials in these simulations, among other factors. Development of the sophisticated technology described in this review to handle the long-range electrostatic interactions has increased the predictive power of these simulations to the point where comparisons between explicit and continuum solvent models can reveal differences that have their true physical origin in the inherent molecularity of the surrounding medium.

  8. Industrial Technology Orientation Curriculum Guide.

    ERIC Educational Resources Information Center

    Illinois State Board of Education, Springfield. Dept. of Adult, Vocational and Technical Education.

    The four courses in this guide were designed to meet the specifications for the career orientation level of Illinois' Education for Employment Curriculum Model. These orientation-level courses can be taken by high school students in any sequence: (1) communication technology; (2) energy utilization technology; (3) production technology; and (4)…

  9. Point contact spectroscopy in oriented La[sub 2-x]Sr[sub x]CuO[sub 4] superconductors; energy gap and Fermi velocity

    SciTech Connect

    Hass, N. ); Deutscher, G. ); Revcolevschi, A.; Dhalenne, G. )

    1994-08-01

    Point contact measurements in oriented La[sub 2-x]Sr[sub x]CuO[sub 4] samples were performed using metal tips. The current-voltage curves measured along the CuO plane direction (ab) are characteristic of the Andreev reflection phenomenon. The superconducting energy gap in the ab plane is determined, [Delta][sub ab] = 6 [+-] 1 meV, with a possibility for the existence of a lower subgap in the plane. A lower limit for the Fermi velocity in the CuO planes is also set by the measurements; V[sub F] [ge] 6 [times] 10[sup 7] cm/sec, which is significantly higher than the average velocity obtained by band calculations. The results are discussed in the context of different models for superconductivity in the layered oxides. In particular, the authors raise the possibility of an anisotropic gap parameter which may indicate a nonstandard s-wave pairing in La[sub 2-x]Sr[sub x]CuO[sub 4]. A comparison with previous results obtained on YBa[sub 2]Cu[sub 3]O[sub 7-[delta

  10. 16th Department of Energy Computer Security Group Training Conference: Proceedings

    SciTech Connect

    Not Available

    1994-04-01

    Various topic on computer security are presented. Integrity standards, smartcard systems, network firewalls, encryption systems, cryptography, computer security programs, multilevel security guards, electronic mail privacy, the central intelligence agency, internet security, and high-speed ATM networking are typical examples of discussed topics. Individual papers are indexed separately.

  11. On the variational computation of a large number of vibrational energy levels and wave functions for medium-sized molecules

    NASA Astrophysics Data System (ADS)

    Mátyus, Edit; Šimunek, Ján; Császár, Attila G.

    2009-08-01

    In a recent publication [J. Chem. Phys. 127, 084102 (2007)], the nearly variational DEWE approach (DEWE denotes Discrete variable representation of the Watson Hamiltonian using the Eckart frame and an Exact inclusion of a potential energy surface expressed in arbitrarily chosen coordinates) was developed to compute a large number of (ro)vibrational eigenpairs for medium-sized semirigid molecules having a single well-defined minimum. In this publication, memory, CPU, and hard disk usage requirements of DEWE, and thus of any DEWE-type approach, are carefully considered, analyzed, and optimized. Particular attention is paid to the sparse matrix-vector multiplication, the most expensive part of the computation, and to rate-determining steps in the iterative Lanczos eigensolver, including spectral transformation, reorthogonalization, and restart of the iteration. Algorithmic improvements are discussed in considerable detail. Numerical results are presented for the vibrational band origins of the C12H4 and C12H2D2 isotopologues of the methane molecule. The largest matrix handled on a personal computer during these computations is of the size of (4•108)×(4•108). The best strategy for determining vibrational eigenpairs depends largely on the actual details of the required computation. Nevertheless, for a usual scenario requiring a large number of the lowest eigenpairs of the Hamiltonian matrix the combination of the thick-restart Lanczos method, shift-fold filtering, and periodic reorthogonalization appears to result in the computationally most feasible approach.

  12. Industrial Orientation.

    ERIC Educational Resources Information Center

    Rasor, Leslie; Brooks, Valerie

    These eight modules for an industrial orientation class were developed by a project to design an interdisciplinary program of basic skills training for disadvantaged students in a Construction Technology Program (see Note). The Drafting module overviews drafting career opportunities, job markets, salaries, educational requirements, and basic…

  13. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

    PubMed Central

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images

  14. Generalized and efficient algorithm for computing multipole energies and gradients based on Cartesian tensors

    PubMed Central

    Lin, Dejun

    2015-01-01

    Accurate representation of intermolecular forces has been the central task of classical atomic simulations, known as molecular mechanics. Recent advancements in molecular mechanics models have put forward the explicit representation of permanent and/or induced electric multipole (EMP) moments. The formulas developed so far to calculate EMP interactions tend to have complicated expressions, especially in Cartesian coordinates, which can only be applied to a specific kernel potential function. For example, one needs to develop a new formula each time a new kernel function is encountered. The complication of these formalisms arises from an intriguing and yet obscured mathematical relation between the kernel functions and the gradient operators. Here, I uncover this relation via rigorous derivation and find that the formula to calculate EMP interactions is basically invariant to the potential kernel functions as long as they are of the form f(r), i.e., any Green’s function that depends on inter-particle distance. I provide an algorithm for efficient evaluation of EMP interaction energies, forces, and torques for any kernel f(r) up to any arbitrary rank of EMP moments in Cartesian coordinates. The working equations of this algorithm are essentially the same for any kernel f(r). Recently, a few recursive algorithms were proposed to calculate EMP interactions. Depending on the kernel functions, the algorithm here is about 4–16 times faster than these algorithms in terms of the required number of floating point operations and is much more memory efficient. I show that it is even faster than a theoretically ideal recursion scheme, i.e., one that requires 1 floating point multiplication and 1 addition per recursion step. This algorithm has a compact vector-based expression that is optimal for computer programming. The Cartesian nature of this algorithm makes it fit easily into modern molecular simulation packages as compared with spherical coordinate-based algorithms. A

  15. Generalized and efficient algorithm for computing multipole energies and gradients based on Cartesian tensors

    SciTech Connect

    Lin, Dejun

    2015-09-21

    Accurate representation of intermolecular forces has been the central task of classical atomic simulations, known as molecular mechanics. Recent advancements in molecular mechanics models have put forward the explicit representation of permanent and/or induced electric multipole (EMP) moments. The formulas developed so far to calculate EMP interactions tend to have complicated expressions, especially in Cartesian coordinates, which can only be applied to a specific kernel potential function. For example, one needs to develop a new formula each time a new kernel function is encountered. The complication of these formalisms arises from an intriguing and yet obscured mathematical relation between the kernel functions and the gradient operators. Here, I uncover this relation via rigorous derivation and find that the formula to calculate EMP interactions is basically invariant to the potential kernel functions as long as they are of the form f(r), i.e., any Green’s function that depends on inter-particle distance. I provide an algorithm for efficient evaluation of EMP interaction energies, forces, and torques for any kernel f(r) up to any arbitrary rank of EMP moments in Cartesian coordinates. The working equations of this algorithm are essentially the same for any kernel f(r). Recently, a few recursive algorithms were proposed to calculate EMP interactions. Depending on the kernel functions, the algorithm here is about 4–16 times faster than these algorithms in terms of the required number of floating point operations and is much more memory efficient. I show that it is even faster than a theoretically ideal recursion scheme, i.e., one that requires 1 floating point multiplication and 1 addition per recursion step. This algorithm has a compact vector-based expression that is optimal for computer programming. The Cartesian nature of this algorithm makes it fit easily into modern molecular simulation packages as compared with spherical coordinate-based algorithms. A

  16. Examining Motivational Orientation and Learning Strategies in Computer-Supported Self-Directed Learning (CS-SDL) for Mathematics: The Perspective of Intrinsic and Extrinsic Goals

    ERIC Educational Resources Information Center

    Lao, Andrew Chan-Chio; Cheng, Hercy N. H.; Huang, Mark C. L.; Ku, Oskar; Chan, Tak-Wai

    2017-01-01

    One-to-one technology, which allows every student to receive equal access to learning tasks through a personal computing device, has shown increasing potential for self-directed learning in elementary schools. With computer-supported self-directed learning (CS-SDL), students may set their own learning goals through the suggestions of the system…

  17. Effects of Gendered Language on Gender Stereotyping in Computer-Mediated Communication: The Moderating Role of Depersonalization and Gender-Role Orientation

    ERIC Educational Resources Information Center

    Lee, Eun-Ju

    2007-01-01

    This experiment examined what situational and dispositional features moderate the effects of linguistic gender cues on gender stereotyping in anonymous, text-based computer-mediated communication. Participants played a trivia game with an ostensible partner via computer, whose comments represented either prototypically masculine or feminine…

  18. Are Computer-Oriented Librarians Really Incompetent? Excerpts From the Proceedings of a LARC Meeting Held During the ALA Conference in Dallas, Texas, June 24, 1971.

    ERIC Educational Resources Information Center

    Library Automation Research and Consulting Association, Tempe, AZ.

    The May 1971 issue of "College and Research Libraries" featured an article by Dr. Ellsworth Mason which constitutes an all-out attack on the application of computer technology to library systems. Dr. Mason views the computer-based technology to library systems developed to date (at least the ones he has studied) as unqualified disasters from a…

  19. Communication: Two-component ring-coupled-cluster computation of the correlation energy in the random-phase approximation

    NASA Astrophysics Data System (ADS)

    Krause, Katharina; Klopper, Wim

    2013-11-01

    Within the framework of density-functional theory, the correlation energy is computed in the random-phase approximation (RPA) using spinors obtained from a two-component relativistic Kohn-Sham calculation accounting for spin-orbit interactions. Ring-coupled-cluster equations are solved to obtain the two-component RPA correlation energy. Results are presented for the hydrides of the halogens Br, I, and At as well as of the coinage metals Cu, Ag, and Au, based on two-component relativistic exact-decoupling Kohn-Sham calculations.

  20. Communication: Two-component ring-coupled-cluster computation of the correlation energy in the random-phase approximation

    SciTech Connect

    Krause, Katharina; Klopper, Wim

    2013-11-21

    Within the framework of density-functional theory, the correlation energy is computed in the random-phase approximation (RPA) using spinors obtained from a two-component relativistic Kohn–Sham calculation accounting for spin–orbit interactions. Ring-coupled-cluster equations are solved to obtain the two-component RPA correlation energy. Results are presented for the hydrides of the halogens Br, I, and At as well as of the coinage metals Cu, Ag, and Au, based on two-component relativistic exact-decoupling Kohn–Sham calculations.