WorldWideScience
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TEP process flow diagram  

Energy Technology Data Exchange (ETDEWEB)

This presentation describes the development of the proposed Process Flow Diagram (PFD) for the Tokamak Exhaust Processing System (TEP) of ITER. A brief review of design efforts leading up to the PFD is followed by a description of the hydrogen-like, air-like, and waterlike processes. Two new design values are described; the mostcommon and most-demanding design values. The proposed PFD is shown to meet specifications under the most-common and mostdemanding design values.

Wilms, R Scott [Los Alamos National Laboratory; Carlson, Bryan [Los Alamos National Laboratory; Coons, James [Los Alamos National Laboratory; Kubic, William [Los Alamos National Laboratory

2008-01-01

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TEP process flow diagram  

International Nuclear Information System (INIS)

This presentation describes the development of the proposed Process Flow Diagram (PFD) for the Tokamak Exhaust Processing System (TEP) of ITER. A brief review of design efforts leading up to the PFD is followed by a description of the hydrogen-like, air-like, and waterlike processes. Two new design values are described; the mostcommon and most-demanding design values. The proposed PFD is shown to meet specifications under the most-common and mostdemanding design values.

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Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Process Flow Diagram Mass Balance Calculations  

International Nuclear Information System (INIS)

The purpose of these calculations is to develop the material balances for documentation of the Canister Storage Building (CSB) Process Flow Diagram (PFD) and future reference. The attached mass balances were prepared to support revision two of the PFD for the CSB. The calculations refer to diagram H-2-825869

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Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Process Flow Diagram Mass Balance Calculations  

Energy Technology Data Exchange (ETDEWEB)

The purpose of these calculations is to develop the material balances for documentation of the Canister Storage Building (CSB) Process Flow Diagram (PFD) and future reference. The attached mass balances were prepared to support revision two of the PFD for the CSB. The calculations refer to diagram H-2-825869.

KLEM, M.J.

2000-05-11

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Does the process map influence the outcome of quality improvement work? A comparison of a sequential flow diagram and a hierarchical task analysis diagram  

OpenAIRE

Abstract Background Many quality and safety improvement methods in healthcare rely on a complete and accurate map of the process. Process mapping in healthcare is often achieved using a sequential flow diagram, but there is little guidance available in the literature about the most effective type of process map to use. Moreover there is evidence that the organisation of information in an external representation affects reasoning and decision making. This exploratory study exa...

Ww, Potts Henry; Anderson Janet E; Colligan Lacey; Berman Jonathan

2010-01-01

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Does the process map influence the outcome of quality improvement work? A comparison of a sequential flow diagram and a hierarchical task analysis diagram  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Many quality and safety improvement methods in healthcare rely on a complete and accurate map of the process. Process mapping in healthcare is often achieved using a sequential flow diagram, but there is little guidance available in the literature about the most effective type of process map to use. Moreover there is evidence that the organisation of information in an external representation affects reasoning and decision making. This exploratory study examined whether the type of process map - sequential or hierarchical - affects healthcare practitioners' judgments. Methods A sequential and a hierarchical process map of a community-based anti coagulation clinic were produced based on data obtained from interviews, talk-throughs, attendance at a training session and examination of protocols and policies. Clinic practitioners were asked to specify the parts of the process that they judged to contain quality and safety concerns. The process maps were then shown to them in counter-balanced order and they were asked to circle on the diagrams the parts of the process where they had the greatest quality and safety concerns. A structured interview was then conducted, in which they were asked about various aspects of the diagrams. Results Quality and safety concerns cited by practitioners differed depending on whether they were or were not looking at a process map, and whether they were looking at a sequential diagram or a hierarchical diagram. More concerns were identified using the hierarchical diagram compared with the sequential diagram and more concerns were identified in relation to clinical work than administrative work. Participants' preference for the sequential or hierarchical diagram depended on the context in which they would be using it. The difficulties of determining the boundaries for the analysis and the granularity required were highlighted. Conclusions The results indicated that the layout of a process map does influence perceptions of quality and safety problems in a process. In quality improvement work it is important to carefully consider the type of process map to be used and to consider using more than one map to ensure that different aspects of the process are captured.

Potts Henry WW

2010-01-01

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Quantifying the implicit process flow abstraction in SBGN-PD diagrams with Bio-PEPA  

Directory of Open Access Journals (Sweden)

Full Text Available For a long time biologists have used visual representations of biochemical networks to gain a quick overview of important structural properties. Recently SBGN, the Systems Biology Graphical Notation, has been developed to standardise the way in which such graphical maps are drawn in order to facilitate the exchange of information. Its qualitative Process Diagrams (SBGN-PD are based on an implicit Process Flow Abstraction (PFA that can also be used to construct quantitative representations, which can be used for automated analyses of the system. Here we explicitly describe the PFA that underpins SBGN-PD and define attributes for SBGN-PD glyphs that make it possible to capture the quantitative details of a biochemical reaction network. We implemented SBGNtext2BioPEPA, a tool that demonstrates how such quantitative details can be used to automatically generate working Bio-PEPA code from a textual representation of SBGN-PD that we developed. Bio-PEPA is a process algebra that was designed for implementing quantitative models of concurrent biochemical reaction systems. We use this approach to compute the expected delay between input and output using deterministic and stochastic simulations of the MAPK signal transduction cascade. The scheme developed here is general and can be easily adapted to other output formalisms.

Jane Hillston

2009-10-01

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Automation of process accountability flow diagrams at Los Alamos National Laboratory's Plutonium Facility  

International Nuclear Information System (INIS)

Many industrial processes (including reprocessing activities; nuclear fuel fabrication; and material storage, measurement and transfer) make use of process flow diagrams. These flows can be used for material accountancy and for data analysis. At Los Alamos National Laboratory (LANL), the Technical Area (TA)-55 Plutonium Facility is home to various research and development activities involving the use of special nuclear material (SNM). A facility conducting research and development (R and D) activities using SNM must satisfy material accountability guidelines. All processes involving SNM or tritium processing, at LANL, require a process accountability flow diagram (PAFD). At LANL a technique was developed to generate PAFDs that can be coupled to a relational database for use in material accountancy. These techniques could also be used for propagation of variance, measurement control, and inventory difference analysis. The PAFD is a graphical representation of the material flow during a specific process. PAFDs are currently stored as PowerPoint files. In the PowerPoint format, the data captured by the PAFD are not easily accessible. Converting the PAFDs to an accessible electronic format is desirable for several reasons. Any program will be able to access the data contained in the PAFD. For the PAFD data to be useful in applications such as an expert system for data checking, SNM accountability, inventory difference evaluation, measurement control, and other kinds of anmeasurement control, and other kinds of analysis, it is necessary to interface directly with the information contained within the PAFD. The PAFDs can be approved and distributed electronically, eliminating the paper copies of the PAFDs and ensuring that material handlers have the current PAFDs. Modifications to the PAFDs are often global. Storing the data in an accessible format would eliminate the need to manually update each of the PAFDs when a global change has occurred. The goal was to determine a software package that would store the PAFDs in an accessible format that could be interfaced by various programs. After evaluating several commercial relational database and graphing software packages, VISIO Enterprise was selected. LANL is in the process of completing conversion of the existing PAFDs into VISIO Enterprise. A number of the PAFDs have been converted to VISIO Enterprise, and the data from the drawings have been exported to an ACCESS database. After the conversion has taken place, the data contained in the PAFDs will be accessible for various programs. The data that was once stored in PowerPoint will now be available for tools, including expert analysis, propagation of a variance, SNM accountability, inventory difference analysis, measurement control, and other analysis tools that have yet to be identified. Converting from the PowerPoint format to a drawing stored as a relational database will improve the ability of plant personnel to interface with the PAFD

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Physiology Flow-Diagram Models  

Science.gov (United States)

A set of physiology flow-diagrams for the cardiovascular system, cardiac auto-rhythmic cell, cardiac contractile cell, respiratory system, coagulation/hemostasis, digestive system, excretion, and autonomic nervous system. These flow-diagrams show cause-and-effect markup and have accompanying tutorials.

PhD Sandra J Bruner (Polk Community College Biology)

2005-10-04

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Business Process Flow Diagrams in Tissue Bank Informatics System Design, and Identification and Communication of Best Practices: The Pharmaceutical Industry Experience.  

Science.gov (United States)

Pfizer, Inc.'s Tissue Bank, in conjunction with Pfizer's BioBank (biofluid repository), endeavored to create an overarching internal software package to cover all general functions of both research facilities, including sample receipt, reconciliation, processing, storage, and ordering. Business process flow diagrams were developed by the Tissue Bank and Informatics teams as a way of characterizing best practices both within the Bank and in its interactions with key internal and external stakeholders. Besides serving as a first step for the software development, such formalized process maps greatly assisted the identification and communication of best practices and the optimization of current procedures. The diagrams shared here could assist other biospecimen research repositories (both pharmaceutical and other settings) for comparative purposes or as a guide to successful informatics design. Therefore, it is recommended that biorepositories consider establishing formalized business process flow diagrams for their laboratories, to address these objectives of communication and strategy. PMID:23386924

McDonald, Sandra A; Velasco, Elizabeth; Ilasi, Nicholas T

2010-12-01

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Formalization of the Data Flow Diagram Rules for Consistency Check  

Directory of Open Access Journals (Sweden)

Full Text Available In system development life cycle (SDLC, a system model can be developed using Data Flow Diagram(DFD. DFD is graphical diagrams for specifying, constructing and visualizing the model of a system.DFD is used in defining the requirements in a graphical view. In this paper, we focus on DFD and itsrules for drawing and defining the diagrams. We then formalize these rules and develop the tool based onthe formalized rules. The formalized rules for consistency check between the diagrams are used indeveloping the tool. This is to ensure the syntax for drawing the diagrams is correct and strictly followed.The tool automates the process of manual consistency check between data flow diagrams.

Rosziati Ibrahim

2010-10-01

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Formalization of the data flow diagram rules for consistency check  

CERN Document Server

In system development life cycle (SDLC), a system model can be developed using Data Flow Diagram (DFD). DFD is graphical diagrams for specifying, constructing and visualizing the model of a system. DFD is used in defining the requirements in a graphical view. In this paper, we focus on DFD and its rules for drawing and defining the diagrams. We then formalize these rules and develop the tool based on the formalized rules. The formalized rules for consistency check between the diagrams are used in developing the tool. This is to ensure the syntax for drawing the diagrams is correct and strictly followed. The tool automates the process of manual consistency check between data flow diagrams.

Ibrahim, Rosziati; 10.5121/ijsea.2010.1406

2010-01-01

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Automated Methodologies for the Design of Flow Diagrams for Development and Maintenance Activities  

Science.gov (United States)

The Software Requirements Specification (SRS) of the organization is a text document prepared by strategic management incorporating the requirements of the organization. These requirements of ongoing business/ project development process involve the software tools, the hardware devices, the manual procedures, the application programs and the communication commands. These components are appropriately ordered for achieving the mission of the concerned process both in the project development and the ongoing business processes, in different flow diagrams viz. activity chart, workflow diagram, activity diagram, component diagram and deployment diagram. This paper proposes two generic, automatic methodologies for the design of various flow diagrams of (i) project development activities, (ii) ongoing business process. The methodologies also resolve the ensuing deadlocks in the flow diagrams and determine the critical paths for the activity chart. Though both methodologies are independent, each complements other in authenticating its correctness and completeness.

Shivanand M., Handigund; Shweta, Bhat

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Software Tool Integrating Data Flow Diagrams and Petri Nets  

Science.gov (United States)

Data Flow Diagram - Petri Net (DFPN) is a software tool for analyzing other software to be developed. The full name of this program reflects its design, which combines the benefit of data-flow diagrams (which are typically favored by software analysts) with the power and precision of Petri-net models, without requiring specialized Petri-net training. (A Petri net is a particular type of directed graph, a description of which would exceed the scope of this article.) DFPN assists a software analyst in drawing and specifying a data-flow diagram, then translates the diagram into a Petri net, then enables graphical tracing of execution paths through the Petri net for verification, by the end user, of the properties of the software to be developed. In comparison with prior means of verifying the properties of software to be developed, DFPN makes verification by the end user more nearly certain, thereby making it easier to identify and correct misconceptions earlier in the development process, when correction is less expensive. After the verification by the end user, DFPN generates a printable system specification in the form of descriptions of processes and data.

Thronesbery, Carroll; Tavana, Madjid

2010-01-01

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Planar quark diagrams and binary spin processes  

International Nuclear Information System (INIS)

Contributions of planar diagrams to the binary scattering processes are analyzed. The analysis is based on the predictions of quark-gluon picture of strong interactions for the coupling of reggeons with quarks as well as on the SU(6)-classification of hadrons. The dependence of contributions of nonplanar corrections on spins and quark composition of interacting particles is discussed

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A Formal Model for Data Flow Diagram Rules  

OpenAIRE

A formal model for data flow diagram (DFD) rules is developed by introducing a syntax and semantics for its rules. DFD has been chosen because it is an approach for specifying, constructing and visualizing the model of a system graphically and has been in practical use on a very wide basis but still lacks formal and precise understanding. This formal model can be used to check the correctness of the diagrams and consistency among the diagrams.

Rosziati Ibrahim; Siow Yen Yen

2011-01-01

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A Formal Model for Data Flow Diagram Rules  

Directory of Open Access Journals (Sweden)

Full Text Available A formal model for data flow diagram (DFD rules is developed by introducing a syntax and semantics for its rules. DFD has been chosen because it is an approach for specifying, constructing and visualizing the model of a system graphically and has been in practical use on a very wide basis but still lacks formal and precise understanding. This formal model can be used to check the correctness of the diagrams and consistency among the diagrams.

Rosziati Ibrahim

2011-05-01

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Material flow of production process  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with material flow of the production process. We present the block diagram of material flow and capacities of engine in various plants each other. In this paper is used IPO (Input ? Process ? Output diagram. IPO diagram described process with aspect to input and output. Production program regards string of precision, branch and paralel processes with aspect IPO diagram.Process is not important with aspect to events. We are looking on the process as a ?black box?. For process is used different materials and raw materials. The foudation for material analysis is detailed model of production process with defined flow material, energy, waste etc.Material flow is organised move of mass (material, money, informations, people etc.. Material analysis is made against destination of material flow (i.e. from ending to beginning. Material analysis is performed on the detection demand of individual materials, stocks, forms, etc.For elementary materials and raw materials in which is based production program and which to create better part of production costs is mainly necessary to dedicate the remark. The fluency of material flow concentrates on the respect of the capacitive parameters for individual node from aspect to standardized qualitative parameters and allowed limits.

Hanzelová Marcela

2001-12-01

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Introducing the Circular Flow Diagram to Business Students  

Science.gov (United States)

The circular flow of income diagram is a simplified representation of the functioning of a free-market economic system. It illustrates how businesses interact with the other economic participants within the key macroeconomic markets that coordinate the flow of income through the national economy. Therefore, it can provide students of business with…

Daraban, Bogdan

2010-01-01

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AUTO-LAY: automatic layout generation for procedure flow diagrams  

International Nuclear Information System (INIS)

Nuclear Power Plant Procedures can be seen from essentially two viewpoints: the process and the information management. From the first point of view, it is important to supply the knowledge apt to solve problems connected with the control of the process, from the second one the focus of attention is on the knowledge representation, its structure, elicitation and maintenance, formal quality assurance. These two aspects of procedure representation can be considered and solved separately. In particular, methodological, formal and management issues require long and tedious activities, that in most cases constitute a great barrier for procedures development and upgrade. To solve these problems, Ansaldo is developing DIAM, a wide integrated tool for procedure management to support in procedure writing, updating, usage and documentation. One of the most challenging features of DIAM is AUTO-LAY, a CASE sub-tool that, in a complete automatical way, structures parts or complete flow diagrams. This is a feature that is partially present in some other CASE products, that, anyway, do not allow complex graph handling and isomorphism between video and paper representation AUTO-LAY has the unique prerogative to draw graphs of any complexity, to section them in pages, and to automatically compose a document. This has been recognized in the literature as the most important second-generation CASE improvement. (author). 5 refs., 9 figs

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IGDS/TRAP Interface Program (ITIP). Software Design Document. [network flow diagrams for coal gasification studies  

Science.gov (United States)

The preliminary design of the IGDS/TRAP Interface Program (ITIP) is described. The ITIP is implemented on the PDP 11/70 and interfaces directly with the Interactive Graphics Design System and the Data Management and Retrieval System. The program provides an efficient method for developing a network flow diagram. Performance requirements, operational rquirements, and design requirements are discussed along with sources and types of input and destination and types of output. Information processing functions and data base requirements are also covered.

Jefferys, S.; Johnson, W.

1981-01-01

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Microsoft Visio 2013 business process diagramming and validation  

CERN Document Server

Microsoft Visio 2013 Business Process Diagramming and Validation provides a comprehensive and practical tutorial including example code and demonstrations for creating validation rules, writing ShapeSheet formulae, and much more.If you are a Microsoft Visio 2013 Professional Edition power user or developer who wants to get to grips with both the essential features of Visio 2013 and the validation rules in this edition, then this book is for you. A working knowledge of Microsoft Visio and optionally .NET for the add-on code is required, though previous knowledge of business process diagramming

Parker, David

2013-01-01

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Andreas Acrivos Dissertation Prize Lecture: Stability of inviscid flows from bifurcation diagrams exploiting a variational argument  

Science.gov (United States)

Steady fluid solutions play a special role in the dynamics of a flow: stable states may be realized in practice, while unstable ones may act as attractors. Unfortunately, determining stability is often a process far more laborious than finding steady states; indeed, even for simple vortex or wave flows, stability properties have often been the subject of debate. We consider here a stability idea originating with Lord Kelvin (1876), which involves using the second variation of the energy, 2?E, to establish bounds on a perturbation. However, for numerically obtained flows, computing 2?E explicitly is often not feasible. To circumvent this issue, Saffman & Szeto (1980) proposed an argument linking changes in 2?E to turning points in a bifurcation diagram, for families of steady flows. Later work has shown that this argument is unreliable; the two key issues are associated with the absence of a formal turning-point theory, and with the inability to detect bifurcations (Dritschel 1995, and references therein). In this work, we build on ideas from bifurcation theory, and link turning points in a velocity-impulse diagram to changes in 2?E; in addition, this diagram delivers the direction of the change of 2?E, thereby providing information as to whether stability is gained or lost. To detect hidden solution branches, we introduce to these fluid problems concepts from imperfection theory. The resulting approach, involving ``imperfect velocity-impulse" diagrams, leads us to new and surprising results for a wide range of fundamental vortex and wave flows; we mention here the calculation of the first steady vortices without any symmetry, and the uncovering of the complete solution structure for vortex pairs. In addition, we find precise agreement with available results from linear stability analysis.

Luzzatto-Fegiz, Paolo

2011-11-01

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Improving The Decisional Process By Using UML Diagrams  

Directory of Open Access Journals (Sweden)

Full Text Available In the last years, the world has moved from predominantly industrial society to information society, governed by a new set of rules, which allows access to digital technologies, processing, storage and transmission of information. Organizations include in their decisional process Business Intelligence components, which help the decision-makers to establish the conditions of financial equilibrium, to highlight weaknesses and strengths, to make predictions.Particularly, Unified Modelling Language (UML, as a formal and standardized language, allows the control of the system’s complexity, shows different but complementary views of the organization and ensures independence towards the implementation language and the domain of application. This article aims to show the way UML diagrams are used as support in a decisional process for a hotel company. UML diagrams designed help decisionmakers to analysis and discover the causes, to design and simulation of possible scenarios, to implement and measuring the results.

Udrica Mioara

2012-06-01

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Phase diagrams properties of the mixed traffic flow on a crossroad  

Science.gov (United States)

Based on the Ishibashi and Fukui crossroad traffic flow model [Y. Ishibashi and M. Fukui. J. Phys. Soc. Japan. 70 (2001) 2793], mixed traffic flow (i.e., the fast and slow vehicles with different maximum velocities are mixed) is investigated in this work. According to the numerical simulation results and the principle for constructing the phase diagram, phase diagrams for mixed traffic flow are constructed. It is noted that the topology of these phase diagrams is similar to that of phase diagrams for homogeneous vehicles (which refers to slow vehicles only). From the phase diagrams, it is evident that mixed traffic flow is influenced by the mixing rate f (fraction of slow and fast vehicles) in regions II and V, but not in other regions. Although a mixture of fast and slow vehicles is introduced in the crossroad traffic flow model, the separation between phases in the phase diagrams remains linear. For a given q (the vehicle density on the northbound road), one flow plateau appears in regions IIx or IVy, while two maximum flow plateaus appear in region V in each of the phase diagrams. The maximum flow values in region V reflect the maximum traffic capacity for the traffic system as defined in this work. Since mixed traffic flow is a common phenomenon in real traffic, this work may offer help in real traffic simulations and traffic management.

Li, Qi-Lang; Wang, Bing-Hong; Liu, Mu-Ren

2010-11-01

26

Diagram representations of charge pumping processes in CMOS transistors  

International Nuclear Information System (INIS)

A diagram representation method is proposed to interpret the complicated charge pumping (CP) processes. The fast and slow traps in CP measurement are defined. Some phenomena such as CP pulse rise/fall time dependence, frequency dependence, the voltage dependence for the fast and slow traps, and the geometric CP component are clearly illustrated at a glance by the diagram representation. For the slow trap CP measurement, there is a transition stage and a steady stage due to the asymmetry of the electron and hole capture, and the CP current is determined by the lower capturing electron or hole component. The method is used to discuss the legitimacy of the newly developed modified charge pumping method. (semiconductor devices)

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Diagram representations of charge pumping processes in CMOS transistors  

Energy Technology Data Exchange (ETDEWEB)

A diagram representation method is proposed to interpret the complicated charge pumping (CP) processes. The fast and slow traps in CP measurement are defined. Some phenomena such as CP pulse rise/fall time dependence, frequency dependence, the voltage dependence for the fast and slow traps, and the geometric CP component are clearly illustrated at a glance by the diagram representation. For the slow trap CP measurement, there is a transition stage and a steady stage due to the asymmetry of the electron and hole capture, and the CP current is determined by the lower capturing electron or hole component. The method is used to discuss the legitimacy of the newly developed modified charge pumping method. (semiconductor devices)

Huang Xinyun; Jiao Guangfan; Cao Wei; Huang Darning; Li Mingfu [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 201203 (China); Shen Chen, E-mail: mfli@fudan.edu.c [SNDL, ECE Department, National University of Singapore, Singapore 117576 (Singapore)

2010-08-15

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Direct control flow testing on function block diagrams  

International Nuclear Information System (INIS)

In this paper, we propose a testing technique that can directly test FBD programs without generating intermediate code for testing purpose. The previous PLC-based software testing generates an intermediate code such as C, which is equivalent to the original FBD, and targets an intermediate code. In order to apply unit and integration testing techniques to FBDs, we transform FBD program into a control flow graph and apply existing control flow testing coverage criteria to the graph. With our approach, PLC based software designed in FBD language can be tested cost-efficiently because we do not need to generate intermediate code. To demonstrate the usefulness of the proposed method, we use a trip logic of BP (Bistable Process) in DPPS (Digital Plant Protection System) RPS (Reactor Protection System), which is currently being developed at KNICS (KNICS, -) in Korea. (author)

29

Flow regimes and phase diagram of inertial particle suspensions  

CERN Document Server

The aim of this Letter is to characterize the flow regimes of suspensions of finite-size solid particles in a viscous fluid at finite inertia. We explore the system behavior as function of the particle volume fraction and the Reynolds number (the ratio of flow and particle inertia to viscous forces). Unlike single phase flows where a clear distinction exists between the laminar and the turbulent regime, three different states can be identified in the presence of a particulate phase, with smooth transitions between them. At low volume fractions, the flow becomes turbulent when increasing the Reynolds number, transitioning from the laminar regime dominated by viscous forces to the turbulent regime characterized by enhanced momentum transport by turbulent eddies. At larger volume fractions, we identify a new state characterized by an even larger increase of the wall friction. The wall friction increases with the Reynolds number (inertial effects) while the turbulent transport is unaffected, as in a state of inte...

Lashgari, Iman; Breugem, Wim-Paul; Brandt, Luca

2014-01-01

30

Fundamental diagram in traffic flow of mixed vehicles on multi-lane highway  

Science.gov (United States)

We study the fundamental diagram for traffic flow of vehicular mixture on a multi-lane highway. We present the car-following model of multi-lane traffic in which slow and fast vehicles flow with changing lanes. We investigate the traffic states of the vehicular mixture under the periodic boundary. Two values of the current appear at a density and two current curves are obtained. Vehicles move with changing lanes in the traffic state of high current, while vehicles move without changing lanes in the traffic state of low current. They depend on the density, the fraction of slow vehicles, and the initial condition. In the high-current curve, the jamming transition between the free flow and the jammed state occurs at a low density. The fundamental diagrams (current-density diagrams) are shown for the single-lane, two-lane, three-lane, and four-lane traffics.

Tanaka, Katsunori; Nagatani, Takashi; Masukura, Shuichi

2008-09-01

31

Stress-Minimizing Orthogonal Layout of Data Flow Diagrams with Ports  

OpenAIRE

We present a fundamentally different approach to orthogonal layout of data flow diagrams with ports. This is based on extending constrained stress majorization to cater for ports and flow layout. Because we are minimizing stress we are able to better display global structure, as measured by several criteria such as stress, edge-length variance, and aspect ratio. Compared to the layered approach, our layouts tend to exhibit symmetries, and eliminate inter-layer whitespace, ma...

Ru?egg, Ulf; Kieffer, Steve; Dwyer, Tim; Marriott, Kim; Wybrow, Michael

2014-01-01

32

Interpreting Evolutionary Diagrams: When Topology and Process Conflict  

Science.gov (United States)

The authors argue that some diagrams in biology textbooks and the popular press presented as depicting evolutionary relationships suggest an inappropriate (anagenic) conception of evolutionary history. The goal of this research was to provide baseline data that begin to document how college students conceptualize the evolutionary relationships…

Catley, Kefyn M.; Novick, Laura R.; Shade, Courtney K.

2010-01-01

33

Complex Fundamental Diagram of Traffic Flow in the Deep Lefortovo Tunnel (Moscow)  

CERN Document Server

The fundamental diagram for tunnel traffic is constructed based on the empirical data collected during the last two years in the deep long branch of the Lefortovo tunnel located on the 3$^\\text{rd}$ circular highway of Moscow. This tunnel of length 3 km is equipped with a dense system of stationary radiodetetors distributed uniformly along it chequerwise at spacing of 60 m. The data were averaged over 30 s. Each detector measures three characteristics of the vehicle ensemble; the flow rate, the car velocity, and the occupancy for three lanes individually. The conducted analysis reveals an original complex structure of the fundamental diagram.

Lubashevsky, Ihor; Livshits, Boris

2007-01-01

34

Microsoft excel's automatic data processing and diagram drawing of RIA internal quality control parameters  

International Nuclear Information System (INIS)

We did automatic data processing and diagram drawing of various parameters of RIA' s internal quality control (IQC)by the use of Microsoft Excel (ME). By use of AVERAGE and STDEV of ME, we got x-bar, s and CV%. With pearson, we got the serum quality control coefficients (r). Inputing the original data to diagram's self-definition item, the diagram was drawn automatically. By the use of logic judging, we got the quality control judging results with the status, timing and data of various quality control parameters. For the past four years, the ME data processing and diagram drawing as well as quality control judging have been showed to be accurate, convenient and correct. It was quick and easy to manage and the automatic computer processing of RIA's IQC was realized. Conclusion: the method is applicable to all types of RIA' s IQC. (authors)

35

Development of the Functional Flow Block Diagram for the J-2X Rocket Engine System  

Science.gov (United States)

The J-2X program calls for the upgrade of the Apollo-era Rocketdyne J-2 engine to higher power levels, using new materials and manufacturing techniques, and with more restrictive safety and reliability requirements than prior human-rated engines in NASA history. Such requirements demand a comprehensive systems engineering effort to ensure success. Pratt & Whitney Rocketdyne system engineers performed a functional analysis of the engine to establish the functional architecture. J-2X functions were captured in six major operational blocks. Each block was divided into sub-blocks or states. In each sub-block, functions necessary to perform each state were determined. A functional engine schematic consistent with the fidelity of the system model was defined for this analysis. The blocks, sub-blocks, and functions were sequentially numbered to differentiate the states in which the function were performed and to indicate the sequence of events. The Engine System was functionally partitioned, to provide separate and unique functional operators. Establishing unique functional operators as work output of the System Architecture process is novel in Liquid Propulsion Engine design. Each functional operator was described such that its unique functionality was identified. The decomposed functions were then allocated to the functional operators both of which were the inputs to the subsystem or component performance specifications. PWR also used a novel approach to identify and map the engine functional requirements to customer-specified functions. The final result was a comprehensive Functional Flow Block Diagram (FFBD) for the J-2X Engine System, decomposed to the component level and mapped to all functional requirements. This FFBD greatly facilitates component specification development, providing a well-defined trade space for functional trades at the subsystem and component level. It also provides a framework for function-based failure modes and effects analysis (FMEA), and a rigorous baseline for the functional architecture.

White, Thomas; Stoller, Sandra L.; Greene, WIlliam D.; Christenson, Rick L.; Bowen, Barry C.

2007-01-01

36

The phase diagram of quantum gravity from diffeomorphism-invariant RG-flows  

CERN Document Server

We evaluate the phase diagram of quantum gravity within a fully diffeomorphism-invariant renormalisation group approach. The construction is based on the geometrical or Vilkovisky-DeWitt effective action. We also resolve the difference between the fluctuation metric and the background metric. This allows for fully background-independent flows in gravity. The results provide further evidence for the ultraviolet fixed point scenario in quantum gravity with quantitative changes for the fixed point physics. We also find a stable infrared fixed point related to classical Einstein gravity. Implications and possible extensions are discussed.

Donkin, Ivan

2012-01-01

37

Power diagrams and interaction processes for unions of discs  

DEFF Research Database (Denmark)

We study a flexible class of finite disc process models with interaction between the discs. We let U denote the random set given by the union of discs, and use for the disc process an exponential family density with the canonical sufficient statistic only depending on geometric properties of U such as the area, perimeter, Euler-Poincar´e characteristic, and number of holes. This includes the quarmass-interaction process and the continuum random cluster model as special cases. Viewing our model as a connected component Markov point process, and thereby establish local and spatial Markov properties, becomes useful for handling the problem of edge effects when only U is observed within a bounded observation window. The power tessellation and its dual graph become major tools when establishing inclusion-exclusion formulae, formulae for computing geometric characteristics of U, and stability properties of the underlying disc process density. Algorithms for constructing the power tessellation of U and for simulating the disc process are discussed, and the software is made public available.

MØller, Jesper; Helisova, Katarina

2007-01-01

38

FMEF Electrical single line diagram and panel schedule verification process  

International Nuclear Information System (INIS)

Since the FMEF did not have a mission, a formal drawing verification program was not developed, however, a verification process on essential electrical single line drawings and panel schedules was established to benefit the operations lock and tag program and to enhance the electrical safety culture of the facility. The purpose of this document is to provide a basis by which future landlords and cognizant personnel can understand the degree of verification performed on the electrical single lines and panel schedules. It is the intent that this document be revised or replaced by a more formal requirements document if a mission is identified for the FMEF

39

Control structures for flow process  

Directory of Open Access Journals (Sweden)

Full Text Available In the industrial domain, a large number of applications is covered by slow processes, including the flow, the pressure, the temperature and the level control. Each control system must be treated in steady and dynamic states and from the point of view of the possible technical solutions. Based on mathematical models of the processes and design calculations, PC programs allow simulation and the determination of the control system performances.The paper presents a part of an industrial process with classical control loops of flow and temperature. The mathematical model of the flow control process was deducted, the control structure, based on experimental criterions, was designed and the version witch ensure the imposed performances was chosen. Using Matlab, the robustness performances were studied.

Mircea Dul?u

2011-12-01

40

IGDS/TRAP Interface Program (ITIP). Software User Manual (SUM). [network flow diagrams for coal gasification studies  

Science.gov (United States)

This specification establishes the requirements, concepts, and preliminary design for a set of software known as the IGDS/TRAP Interface Program (ITIP). This software provides the capability to develop at an Interactive Graphics Design System (IGDS) design station process flow diagrams for use by the NASA Coal Gasification Task Team. In addition, ITIP will use the Data Management and Retrieval System (DMRS) to maintain a data base from which a properly formatted input file to the Time-Line and Resources Analysis Program (TRAP) can be extracted. This set of software will reside on the PDP-11/70 and will become the primary interface between the Coal Gasification Task Team and IGDS, DMRS, and TRAP. The user manual for the computer program is presented.

Jefferys, S.; Johnson, W.; Lewis, R.; Rich, R.

1981-01-01

41

Mathematics Teaching and Learning as a Mediating Process: The Case of Tape Diagrams  

Science.gov (United States)

This article examines how visual representations may mediate the teaching and learning of mathematics over time in Japanese elementary classrooms. Using the Zone of Proximal Development Mathematical Learning Model (Murata & Fuson, 2006; Fuson & Murata, 2007), the process of mediation is explicated. The tape diagram, a central visual representation…

Murata, Aki

2008-01-01

42

Phase diagrams of heterogeneous traffic flow at a single intersection in a deterministic Fukui-Ishibashi cellular automata traffic model  

Science.gov (United States)

This paper studies heterogeneous traffic flow that comprises two types of vehicles with different lengths at a single intersection consisting of two perpendicular one-lane roads. Based on theoretical analysis and computer simulations, we have presented the phase diagrams which consist of five regions and the topological structure of which is independent of the maximum velocity of vehicles m. The analytical formulas of the flows on the two roads have been obtained in all regions of the phase diagram, which depends on whether m is even or odd or m = 1. The analytical formulas are in good agreement with simulation results.

Li, Qi-Lang; Jiang, Rui; Min, Jie; Xie, Jia-Rong; Wang, Bing-Hong

2014-10-01

43

Ring diagram analysis of near-surface flows in the Sun  

CERN Document Server

Ring diagram analysis of solar oscillation power spectra obtained from MDI data is carried out to study the velocity fields in the outer part of the solar convection zone. The three dimensional power spectra are fitted to a model which has a Lorentzian profile in frequency and which includes the advection of the wave front by horizontal flows, to obtain the two components of the sub-surface flows as a function of the horizontal wave number and radial order of the oscillation modes. This information is then inverted using OLA and RLS methods to infer the variation in horizontal flow velocity with depth. The average rotation velocity at different latitudes obtained by this technique agrees reasonably with helioseismic estimates made using frequency splitting data. The shear layer just below the solar surface appears to consist of two parts with the outer part up to a depth of 4 Mm, where the velocity gradient does not show any reversal up to a latitude of 60 degrees. In the deeper part the velocity gradient sho...

Basu, S; Tripathy, S C; Basu, Sarbani

1999-01-01

44

Flow-guided assembly processes.  

Science.gov (United States)

This Concept article focuses on capillary, hydrodynamics and electrokinetic flow-guided assembly processes that can produce patterned or gradient functional surfaces either on solid surfaces or in deep micro- and nanoscale channels. This concept has the potential to produce low-cost nanostructures, internal surface modifications, and devices in nanomedicine. PMID:18351685

Wang, Shengnian; Guan, Jingjiao; Lee, L James

2008-05-16

45

Padé approximants, optimal renormalization scales, and momentum flow in Feynman diagrams  

CERN Document Server

We show that the Padé Approximant (PA) approach for resummation of perturbative series in QCD provides a systematic method for approximating the flow of momentum in Feynman diagrams. In the large-$\\beta_0$ limit, diagonal PA's generalize the Brodsky-Lepage-Mackenzie (BLM) scale-setting method to higher orders in a renormalization scale- and scheme-invariant manner, using multiple scales that represent Neubert's concept of the distribution of momentum flow through a virtual gluon. If the distribution is non-negative, the PA's have only real roots, and approximate the distribution function by a sum of delta-functions, whose locations and weights are identical to the optimal choice provided by the Gaussian quadrature method for numerical integration. We show how the first few coefficients in a perturbative series can set rigorous bounds on the all-order momentum distribution function, if it is positive. We illustrate the method with the vacuum polarization function and the Bjorken sum rule computed in the large...

Brodsky, S J; Gardi, E; Karliner, M M; Samuel, Mark A; Brodsky, Stanley J.; Ellis, John; Gardi, Einan; Karliner, Marek; Samuel, Mark. A.

1997-01-01

46

Padé approximants, optimal renormalization scales, and momentum flow in Feynman diagrams  

Science.gov (United States)

We show that the Padé approximant (PA) approach for resummation of perturbative series in QCD provides a systematic method for approximating the flow of momentum in Feynman diagrams. In the large-?0 limit, diagonal PA's generalize the Brodsky-Lepage-Mackenzie (BLM) scale-setting method to higher orders in a renormalization scale- and scheme-invariant manner, using multiple scales that represent Neubert's concept of the distribution of momentum flow through a virtual gluon. If the distribution is non-negative, the PA's have only real roots, and approximate the distribution function by a sum of ? functions, whose locations and weights are identical to the optimal choice provided by the Gaussian quadrature method for numerical integration. We show how the first few coefficients in a perturbative series can set rigorous bounds on the all-order momentum distribution function, if it is positive. We illustrate the method with the vacuum polarization function and the Bjorken sum rule computed in the large-?0 limit.

Brodsky, Stanley J.; Ellis, John; Gardi, Einan; Karliner, Marek; Samuel, Mark A.

1997-12-01

47

Flow diagram of the longitudinal and Hall conductivities in ac regime in the disordered graphene quantum Hall system  

International Nuclear Information System (INIS)

We numerically study the behavior of ?xy(?) and ?xx (?) for graphene QHE system in the ac (frequency ?) domain. We interpret these conductivities with the dynamical scaling analysis. We also discuss the temperature flow of ?xy(?) — ?xx(?) diagram for graphene QHE system in the ac region.

48

Flow Logic for Process Calculi  

DEFF Research Database (Denmark)

Flow Logic is an approach to statically determining the behavior of programs and processes. It borrows methods and techniques from Abstract Interpretation, Data Flow Analysis and Constraint Based Analysis while presenting the analysis in a style more reminiscent of Type Systems. Traditionally developed for programming languages, this article provides a tutorial development of the approach of Flow Logic for process calculi based on a decade of research. We first develop a simple analysis for the ?-calculus; this consists of the specification, semantic soundness (in the form of subject reduction and adequacy results), and a Moore Family result showing that a least solution always exists, as well as providing insights on how to implement the analysis. We then show how to strengthen the analysis technology by introducing reachability components, interaction points, and localized environments, and finally, we extend it to a relational analysis. A Flow Logic is a program logic---in the same sense that a Hoare’s logic is. We conclude with an executive summary presenting the highlights of the approach from this perspective including a discussion of theoretical properties as well as implementation considerations. The electronic supplements present an application of the analysis techniques to a version of the ?-calculus incorporating distribution and code mobility; also the proofs of the main results can be found in the electronic supplements.

Nielson, Hanne Riis; Nielson, Flemming

2012-01-01

49

Potential - oxoacidity diagrams for electrochemical processing of actinides in molten-salt  

International Nuclear Information System (INIS)

Molten-salt based pyroprocessing of nuclear fuels, especially metallic fuels is being considered as a more effective method compared to wet processing route. Lithium and potassium chloride eutectic is one of the most investigated molten salt electrolyte for this purpose. Due to difference in the reduction potential of actinides, rare-earths and other fission products, actinides can be easily separated from other fission product during electrolytic pyroprocessing. However, due to close reduction potentials of actinide species Th, U, Pu, Am, Cm, their separation needs closer investigation of controlling parameters, pO2- and voltage. Therefore, potential-oxoacidity diagrams of these species were calculated in LiCL-KCI eutectic electrolyte at 743 K, with reference to Cl2(1 atm)/Cl- electrode. These diagrams helped in estimating the required oxygen potentials and voltages to selectively reduce different species of actinides to their metallic forms. (author)

50

Development of the web-based site investigation flow diagram in repository development program  

International Nuclear Information System (INIS)

In siting a repository for high level radioactive wastes (HLW), it is essential for consensus building intelligibly and visually present why and how the area is selected as a suitable site. However 'information asymmetry' exists especially between society and an implementation body because various types of investigation, analysis and assessment are implemented in site characterization on the basis of a wide variety of advanced science and technology. Communication between experts (e.g. surveyors and modelers) is also important for efficient and reliable site investigation/ characterization. The Web-based Site Investigation Flow Diagram (SIFD) has been developed as a tool for information sharing among stake holders and society-jointed decision making. To test applicability of the SIFD, virtual site characterization ('dry run') is performed using the existing site investigation data. It is concluded that the web-based SIFD enhance traceability and transparency of the site investigation/ characterization, and therefore it would be a powerful communication tool among experts for efficient and reliable site investigation/characterization and among stake holders for consensus building

51

Cascade processes in plane flows  

Science.gov (United States)

The diffusion of a tracer in a two dimensional turbulent flow which is forced by non-homogeneous distribution is dominated by the structures in the flow. In case of acceleration producing baroclinic vorticity due to density differences, Instabilities such as the Rayleigh-Taylor [1] or the Kelvin-Helmholtz appear. These are investigated using multi-fractal techniques, analyzing mixedness, [2], ESS [3]and higher order order structure functions, that indicate both direct or inverse cascades towards the large scales and producing spectral variations [4]. These can be studied numerically using both DNS and Kinematic Simulation (KS) forcing a set spectra. The direct comparison of the Eulerian and Lagrangian features The mixing processes are compared by mapping the different intermittency (Obtained by relating it to the sixth and third order structure function scaling exponents) and to the measured maximum Fractal dimension showing that and there are a set of functions that provide a complex intermittency scaling. [1] Redondo J.M. and Garzon G. (2004) Multifractal structure and intermittency in Rayleigh-Taylor Driven Fronts. Ed. S. Dalziel www.damtp.cam.ac.uk/iwpctm9/proceedings/IWPCTM9/Papers/Programme.htm [2] Redondo, J.M. and Cantalapiedra I.R. (1993) Mixing in Horizontally Heterogeneous Flows. Jour. Flow Turbulence and Combustion. 51. 217-222. [3] Benzi et al. (1995) On the scaling of 3D homogeneous and isotropic turbulence, Physica D 80, 385-398. [4] Castilla R, Redondo J.M., Gamez P.J., Babiano A. (2007) Coherent vortices and Lagrangian Dynamics in 2D Turbulence. Non-Linear Processes in Geophysics 14. 139-151.

Castilla, R.; Garzon, G.; Redondo, J. M.

2009-04-01

52

From State Diagram to Class Diagram  

DEFF Research Database (Denmark)

UML class diagram and Java source code are interrelated and Java code is a kind of interchange format. Working with UML state diagram in CASE tools, a corresponding xml file is maintained. Designing state diagrams is mostly performed manually using design patterns and coding templates - a time consuming process. This article demonstrates how to compile such a diagram into Java code and later, by reverse engineering, produce a class diagram. The process from state diagram via intermediate SAX parsed xml file to Apache Velocity generated Java code is described. The result is a fast reproducible Java code minimizing maintenance.

Borch, Ole; Madsen, Per Printz

2009-01-01

53

Constructing mammography examination process ontology using affinity diagram and hierarchical task analysis.  

Science.gov (United States)

Mammography is complex and difficult for beginner radiologic technologists (RTs) because knowledge and technical skills rely on one's experience, and it is often difficult for experienced RTs to verbally explain the process to co-workers or beginners. The purpose of this study was to construct a mammography examination process ontology for knowledge sharing among RTs and propose a new ontology construction method using an affinity diagram (AD) and hierarchical task analysis (HTA). First, tasks collected by brainstorming were clustered and connected using the AD. Subsequently, a hierarchical structure was constructed based on the clusters and relations determined in the AD. Finally, a mammography process ontology was determined based on the relations noted in the AD and HTA. As a result, the ontology contained 203 classes and 669 relations. PMID:23920833

Yagahara, Ayako; Tsuji, Shintarou; Fukuda, Akihisa; Yokooka, Yuki; Nishimoto, Naoki; Kurowarabi, Kunio; Ogasawara, Katsuhiko

2013-01-01

54

Two-state shear diagrams for complex fluids in shear flow  

OpenAIRE

The possible ``phase diagrams'' for shear-induced phase transitions between two phases are collected. We consider shear-thickening and shear-thinning fluids, under conditions of both common strain rate and common stress in the two phases, and present the four fundamental shear stress vs. strain-rate curves and discuss their concentration dependence. We outline how to construct more complicated phase diagrams, discuss in which class various experimental systems fall, and sket...

Olmsted, Peter D.

1999-01-01

55

UO2 flow freezing processes  

International Nuclear Information System (INIS)

Transient freezing of molten UO2 and UO2-steel mixtures in steel channels is an important functional heat transfer process which occurs in the course of Liquid Metal-Cooled Fast Breeder Reactor (LMFBR) Hypothetical Core Disruptive Accidents (HCDA). Fuel freezing processes can influence both the transient overpower (TOP) and transient undercooling (TUC) accidents. In the absence of freezing, either fuel sweepout or continuous fuel removal can lead to shutdown with a largely coolable geometry in the TOP case and greatly reduce concerns over recriticality in the TUC case. However, with fuel freezing either case may lead to a temporarily ''bottled-up core'' condition which is relieved by melting of the initially formed plugs. Whether further freezing occurs in either the upward or downward direction through the core support structure is of interest in determining the decay heat level for Post-Accident Heat Removal (PAHR). Attention is focused on the freezing of ceramic fuel in steel channels. A discussion of the conduction-controlled and bulk freezing mechanisms is given first. A fuel crust stability criterion is proposed, and an explicit formula providing a rough estimate of critical fuel crust disintegration conditions is developed. A comparison of the crust stability criterion with a number of explanatory experimental results is made. A steel ablation-fuel freezing mechanism is identified. If the conditions in the fuel flow are such to prevent fues in the fuel flow are such to prevent fuel crust growth, then the steel wall melting can become catastrophic. Steel ablation rapidly leads to fuel freezing in a bulk manner via turbulent mixing between the relatively ''cold'' molten steel and hot molten fuel. Based on this ablation-freezing concept, simple equations are developed for molten fuel penetration into steel channels. Comparison of the equations with the available experimental results proves favorable

56

Meaning and Abduction as Process-Structure: A Diagram of Reasoning  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is informed by Charles Sanders Peirce’s philosophy as semiotics or the doctrine of signs. The paper’s purpose is to explore Peirce’s category of abduction as not being limited to the inference to the best explanation. In the context of the logic of discovery, abduction is posited as a necessary although not sufficient condition for the production of meanings. The structure of a genuine sign is triadic and represents a synthesis between precognitive ideas and conceptual representations. The novel model of reasoning is offered, based on the mathematical formalism borrowed from Gauss’ interpretation of the complex number. It is suggested that this model in a form of a diagram not only represents a semiotic process-structure but also overcomes the long-standing paradox of new knowledge. For Peirce, it is a diagram as a visual representation that may yield solutions to the otherwise unsolvable logical problems. What appears to us as a paradox is the very presence of abductive, or hypothetical, inference, as Peircean generic category of Firstness within the Thirdness of the total thought-process. Firstness (feeling, Secondness (action, and Thirdness (reason together constitute a dynamic structure of experience.

Inna Semetsky

2009-11-01

57

Systematic fuel cycle systems engineering from 2D flow diagrams to 3D layout  

International Nuclear Information System (INIS)

The ITER fuel cycle systems are designed to supply deuterium-tritium gas mixtures to the ITER fueling systems and to process return gas streams from the vacuum vessel forming the closed inner fuel cycle. The radioactive nature of tritium requires implementation of a multiple barrier concept in order to assure the confinement of tritium within the process equipment. Ventilation and vent detritiation systems are the part of a dynamic confinement barrier which prevents tritium releases to the environment. The ITER fuel cycle systems, ventilation and tritium confinement systems all together form a rather complex chemical plant - the ITER Tritium Plant. Not only because of the complexity of the inner fuel cycle systems and numerous interfaces to the other systems within tritium plant but also because of the procurement sharing integrated planning is required. Interfaces management, configuration control and systems integration requires proper CAD tools and Project Data Management systems. CATIA V4 has been used in the past in ITER for 3D planning. However, only today's version of the software allows linking of the primarily 2D Pipe and Instrumentation Diagrams (P and IDs) into detailed 3D design and layout. The capabilities of the software were demonstrated through proof of principle activities in the ITER CAD office, eventually leading to the decision to deploy CATIA V5 Equipment and Systems (E and S) as general purpose single CAD tool for the design and integration of th tool for the design and integration of the ITER electrical, fluid and mechanical systems. In order to meet engineering requirements of ITER the CATIA V5 E and S project structure and project resources have been established starting from systems classifications, followed by the implementation of the applicable industrial standards, specifications and systems elements libraries into the Project Resources Management (PRM). Catalogues for the piping parts, piping specifications and standards specific for the design of the tritium processing systems and tritium confinement systems will assure implementation of the Design Guidelines and Quality Requirements for the Tritium Plant systems including the standardization of the equipment and design. The paper describes the CATIA V5 E and S project structure, the procedures to develop and maintain the PRM and how the tool is employed to detail the design of Tritium Plant systems. (orig.)

58

18 CFR 260.8 - System flow diagrams: Format No. FERC 567.  

Science.gov (United States)

18 Conservation of Power and Water Resources 1 2010-04-01...Section 260.8 Conservation of Power and Water Resources FEDERAL...31. For purposes of system peak deliveries, the heating...stated pressure and temperature base. (b) The diagram or...

2010-04-01

59

Evolution of the Near-surface Flows Inferred from High-resolution Ring-diagram Analysis of HMI Data  

Science.gov (United States)

Ring-diagram analysis of acoustic waves observed at the photosphere provides in principle a relatively robust determination of the sub-surface flows at a particular time under a particular region. The depth of penetration of the waves is related to the size of the region, hence the depth extent of the measured flows is inversely proportional to the spatial resolution. Most ring-analysis has focused on regions of extent ~15 deg (200 Mm) or more in order to provide reasonable mode sets for inversions. The HMI analysis pipeline however also provides a set of ring fit parameters on a scale three times smaller. These provide flow estimates for the outer 1% (7 Mm) of the Sun only, with very limited depth resolution, but with spatial resolution adequate to map structures.potentially associated with the belts and regions of magnetic activity. There are a number of systematic effects affecting the determination of flows from local helioseismic analysis of regions over different parts of the observable disc, not all well-understood. In this study we characterize those systematic effects with higher spatial resolution. This enable us to remove them more effectively as we map the temporal and spatial evolution of the flows, leaving open the question of their mean structure which is most affected by the systematics. We present results for the ring-diagram determination of the flow anomalies corresponding to the torsional oscillation pattern in differential rotation and analogous patterns in the meridional cell structure over the early part of the current solar cycle observed by HMI.

Bogart, Richard S.; Baldner, Charles; Basu, Sarbani

2014-06-01

60

Water conservation and reuse using the Water Sources Diagram method for batch process: case studies  

Directory of Open Access Journals (Sweden)

Full Text Available The water resources management has been an important factor for the sustainability of industrial processes, since there is a growing need for the development of methodologies aimed at the conservation and rational use of water. The objective of this work was to apply the heuristic-algorithmic method called Water Sources Diagram (WSD, which is used to define the target of minimum water consumption, to batch processes. Scenarios with reuse of streams were generated and evaluated with application of the method from the data of water quantity and concentration of contaminants in the operations. Two case studies aiming to show the reduction of water consumption and wastewater generation, and final treatment costs besides investment in storage tanks, were presented. The scenarios showed great promising, achieving reduction up to 45% in water consumption and wastewater generation, and a reduction of around 37% on cost of storage tanks, without the need to allocate regeneration processes. Thus, the WSD method showed to be a relevant and flexible alternative regarding to systemic tools aimed at minimizing the consumption of water in industrial processes, playing an important role within a program of water resources management.

Fernando Luiz Pellegrini Pessoa

2012-04-01

61

Chemical reactions and processes under flow conditions  

CERN Document Server

Pharmaceutical and fine chemical products are typically synthesised batchwise which is an anomaly since batch processes have a series of practical and economical disadvantages. On the contrary, flow continuous processes present a series of advantages leading to new ways to synthesise chemical products. Flow processes - * enable control reaction parameters more precisely (temperature, residence time, amount of reagents and solvent etc.), leading to better reproducibility, safer and more reliable processes * can be performed more advantageously using immobilized reagents or catalysts * improve t

Luis, Santiago V; Clark, James H

2009-01-01

62

CONVERSIÓN DE DIAGRAMAS DE PROCESOS EN DIAGRAMAS DE CASOS DE USO USANDO AToM³ / CONVERSION OF PROCESSES DIAGRAMS IN USE CASE DIAGRAMS USING AToM³  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Toda pieza de software se origina en el modelo verbal, con el cual se pueden definir los diferentes modelos conceptuales que acerquen el problema a una solución. Las herramientas convencionales para la construcción de los modelos conceptuales no toman en consideración las diferentes reglas de consis [...] tencia que se pueden presentar entre los diferentes modelos. En este artículo se emplea el AToM³ como herramienta para la definición de los meta-modelos del diagrama de procesos y el diagrama de casos de uso, con el fin de reexpresar el primero para obtener algunos elementos básicos del segundo. Abstract in english Every software piece has its origins in the verbal model. With this model, it’s possible to define several conceptual models that allow reaching a solution closer to the problem. Conventional tools for conceptual model building don’t take into account the different consistency rules between differen [...] t models. In this paper we use AToM³ as a tool for the meta-models’ definition of process diagram and use case diagrams, trying to redefine the first to obtain some basic elements from the second.

CARLOS M., ZAPATA J.; CARLOS ALBERTO, ÁLVAREZ..

2005-07-01

63

Digital image processing for flow visualization  

International Nuclear Information System (INIS)

The digital image processing for flow visualization pictures, including air-bubble, smoke tunnel, schlieren, and interference are described. The methods of calculating data are provided. The histogram equalization, spatial convolution, exponential transform, and Wallis transform are introduced

64

Flow, diffusion, and rate processes  

International Nuclear Information System (INIS)

This volume contains recent results obtained for the nonequilibrium thermodynamics of transport and rate processes are reviewed. Kinetic equations, conservation laws, and transport coefficients are obtained for multicomponent mixtures. Thermodynamic principles are used in the design of experiments predicting heat and mass transport coefficients. Highly nonstationary conditions are analyzed in the context of transient heat transfer, nonlocal diffusion in stress fields and thermohydrodynamic oscillatory instabilities. Unification of the dynamics of chemical systems with other sorts of processes (e.g. mechanical) is given. Thermodynamics of reacting surfaces is developed. Admissible reaction paths are studied and a consistency of chemical kinetics with thermodynamics is shown. Oscillatory reactions are analyzed in a unifying approach showing explosive, conservation or damped behavior. A comprehensive review of transport processes in electrolytes and membranes is given. Applications of thermodynamics to thermoelectric systems and ionized gas (plasma) systems are reviewed

65

ASPECTS OF ROBUSTNESS IN FLOW CONTROL PROCESSES  

Directory of Open Access Journals (Sweden)

Full Text Available In the industrial domain, a large number of applications is covered by slow processes, including the flow, the pressure, the temperature and the level control. Each control system must be treated in steady and dynamic states and from the point of view of the possible technical solutions. Based on mathematical models of the processes and design calculations, PC programs allow simulation and the determination of the control system performances. The paper presents a part of an industrial process with classical control loops of flow and temperature. The mathematical model of the flow control process was deducted, the control structure, based on experimental criterions, was designed and the version witch ensure the imposed performances was chosen. Using Matlab, the robustness performances were studied.

Mircea DULAU

2011-11-01

66

Prolog Visualization System Using Logichart Diagrams  

CERN Document Server

We have developed a Prolog visualization system that is intended to support Prolog programming education. The system uses Logichart diagrams to visualize Prolog programs. The Logichart diagram is designed to visualize the Prolog execution flow intelligibly and to enable users to easily correlate the Prolog clauses with its parts. The system has the following functions. (1) It visually traces Prolog execution (goal calling, success, and failure) on the Logichart diagram. (2) Dynamic change in a Prolog program by calling extra-logical predicates, such as `assertz' and `retract', is visualized in real time. (3) Variable substitution processes are displayed in a text widget in real time.

Adachi, Yoshihiro

2009-01-01

67

ESPC Overview: Cash Flows, Scenarios, and Associated Diagrams for Energy Savings Performance Contracts  

Energy Technology Data Exchange (ETDEWEB)

This document is meant to inform state and local decision makers about the process of energy savings performance contracts, and how projected savings and allocated energy-related budgets can be impacted by changes in utility prices.

Tetreault, T.; Regenthal, S.

2011-05-01

68

Three-dimensional flow field observation by laser holographic interferometry and image processing  

Science.gov (United States)

The use of multidirectional laser holographic interferometry and computer tomography to characterize the three-dimensional density field of an air flow is demonstrated. The case of the flow around a sharp cone at angle of attack 20 deg in the 10 x 10-cm test section of the NAL supersonic wind tunnel is presented. The processing steps include acquisition of interferograms, projection data construction, back-projection data construction, conversion to density data, and image processing and display as a computer image. Diagrams and sample images are provided.

Hara, N.; Yoshida, T.

69

On a generalized phase diagram of simultaneous transport processes - a two velocity universal plane of invariance  

International Nuclear Information System (INIS)

The problem concerning void fraction as an additional degree of freedom for a discontinuous density continuum e.g., two-phase systems, is theoretically investigated. A generalized phase diagram has been found to signify the evolution of two-phase systems. With due regard to the objective property of motion, the transformation functions and its properties clearly expose the invariance of relative velocity with superficial velocities as the vector quantities. A fundamental one-to-one mapping involving Euclidean point spaces has been derived demonstrating a two-velocity universal plane of invariance as two-phase equation-of-state. The utility of the phase diagram for steady-state operations is doubtless because of the fundamental property of motion. (author)

70

An Application of Pareto Analysis and Cause-and-Effect Diagram (CED for Minimizing Rejection of Raw Materials in Lamp Production Process  

Directory of Open Access Journals (Sweden)

Full Text Available Flange tube, Glass shell, Lead in Wire (LIW, Filament (Coil and Cap are the most important raw materials in case of Lamp Production Process. Manufacturing processes tend to produce operational wastages due to various reasons, which can be reduced by identifying and eliminating those reasons. It has been a very challenging engineering problem particularly in a multistage manufacturing, where maximum number of processes and activities are performed. With the help of Pareto diagrams, which are mostly used to identify critical areas, the manufacturing process defects in the each stage of the production belt have been prioritized by arranging them in decreasing order of importance. Then cause and effect diagram is being applied to explore possible causes/factors of defects and to determine the causes/factors, which has the greatest effect.
Key words: Lamp production process; Multistage manufacturing; Pareto diagrams; Production belt; Cause and effect diagram

Nafis Ahmad

2011-09-01

71

Process and Data Flow Control in KLOE  

Science.gov (United States)

The core of the KLOE distributed event building system is a switched network. The online processes are distributed over a large set of processors in this network. All processes have to change coherently their state of activity as a consequence of local or remote commands. A fast and reliable message system based on the SNMP protocol has been developed. A command server has been implemented as a non privileged daemon able to respond to "set" and "get" queries on private SNMP variables. This process is able to convert remote set operations into local commands and to map automatically an SNMP subtree on a user-defined set of process variables. Process activity can be continuously monitored by remotely accessing their variables by means of the command server. Only the command server is involved in these operations, without disturbing the process flow. Subevents coming from subdetectors are sent to different nodes of a computing farm for the last stage of event building. Based on features of the SNMP protocol and of the KLOE message system, the Data Flow Control System (DFC) is able to rapidly redirect network traffic, keeping in account the dynamics of the whole DAQ system in order to assure coherent subevent addressing in an asynchronous "push" architecture, without introducing dead time. The KLOE DFC is currently working in the KLOE DAQ system. Its main characteristics and performance are discussed.

Pasqualucci, E.; KLOE Collaboration

2001-10-01

72

Fluid Flow Properties of WAG Injection Processes  

OpenAIRE

Immiscible water-alternating-gas (IWAG) experiments performed on equilibrated fluids are summarised together with the corresponding two-phase gas-oil and water-oil displacements. Experimental studies at reservoir condition and also mechanistic experiments over many years have shown accelerated oil production and higher core flood oil recovery as a result of three-phase flow. The three-phase effects that are included and analysed are; trapped gas, and mobility for secondary process...

Dale, Elisabeth Iren; Skauge, Arne

2008-01-01

73

Grid diagrams and shellability  

OpenAIRE

We explore a somewhat unexpected connection between knot Floer homology and shellable posets, via grid diagrams. Given a grid presentation of a knot K inside S^3, we define a poset which has an associated chain complex whose homology is the knot Floer homology of K. We then prove that the closed intervals of this poset are shellable. This allows us to combinatorially associate a PL flow category to a grid diagram.

Sarkar, Sucharit

2009-01-01

74

Multiphase Flow Modeling of Biofuel Production Processes  

Energy Technology Data Exchange (ETDEWEB)

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01

75

Digital image processing in flow visualization  

International Nuclear Information System (INIS)

Flow visualization results from the interactions between light and matter. Classical methods such as shadowgraphy, schlieren photography, and interferometry visualize variation in the index of refraction induced by changes in density, pressure, or temperature. Nonuniformities of these physical observables modify the phase of optical waves, rendered visible by free-space propagation (shadowgraphy), optical processing in the back focal plane of a lens (schlieren photography), or interference with a reference wave (interferometry). The classical methods visualize variations of the index of refraction or spatial derivatives thereof integrated along the light path through the fluid. Three-dimensional space is projected onto a plane with the corresponding reduction in degrees of freedom. Except for axial symmetric or two-dimensional flows, spatial structures cannot be recovered from a single image

76

Carroll Diagrams  

Science.gov (United States)

In this number sorting activity students must use a Carroll Diagram to determine which two categories each number fits into. This activity can be completed in pairs or groups on printable versions or it can be completed as a whole class using the interactive white board (IWB). Included with this resource are printable versions of the Carroll Diagrams, guiding questions, extension and support suggestions, and a link to more challenging "More Carroll Diagrams".

Team, Nrich

2012-01-01

77

Work flow in process development for energy efficient processes  

International Nuclear Information System (INIS)

Increasing expenditures for energy require an optimization of chemical processes with regard to energy efficiency. Energy efficiency is of course only one aspect of a multi-objective optimization during process development. It will be shown how methods for increasing energy efficiency are integrated in the workflow of BASF's process development for new and existing processes. Special focus will be on the use of exergy analysis and its high relevance to industrial chemical processes. It will be shown how exergy analysis might be used for comparison of different process concepts. Additionally examples will emphasize how an increase of energy efficiency by change of operational conditions can be reached. Also these measures can be interpreted in terms of reduced exergy losses. For all examples the additional investment, if needed, is justified by the savings, which were altogether approximately 7 million euro per year. Highlights: ? Work flow for development of energy efficient processes for new and existing plants in the chemical industry is presented. ? Exergy analysis has been used to identify favorable process concepts. ? Examples with annual savings of about 7 million euro emphasize the use of the method.

78

Chaos and bifurcation in dynamical evolution process of traffic assignment with flow 'mutation'  

International Nuclear Information System (INIS)

Considering such a fact that the traffic demands freshly entering a network do not have perfect information about traffic condition and may then choose routes randomly, in this paper, we present an improved network traffic flow evolution model. The model's properties and fixed points are investigated. Numerical results obtained from a grid network show that the system can converge to one or more fixed points without requiring of positive route flows at initial time, and can be used to approximately simulate the process of realizing user equilibrium state. It is found that oscillations and such apparently irregular behaviors as chaos occur when the model parameter representing intensity of adjusting route flow and OD demand exceeds some values. Bifurcation diagrams of some route flows and OD demands with respect to this model parameter are presented.

79

Process Flow and Functional Analysis of the Iter Cryogenic System  

Science.gov (United States)

The ITER cryogenic system is presently under design by a large international collaboration. It will start commissioning at Cadarache, south of France in 2015. The system is designed to provide an equivalent refrigeration capacity of 65 kW at 4.5 K for the superconducting magnet and 1300 kW at 80 K for the cryoplant pre-cooling stages and the Cryostat Thermal Shields (CTS). The cryoplant consists of three 4.5 K refrigerators and two 80 K helium loops coupled with two LN2 modules. Two 4.5 K modules are dedicated to the magnet system and a small one is devoted to the cryopumps and Pellet Injection System. One Interconnection box interfaces the cryoplant and a complex cryodistribution system which includes 5 Auxiliary Cold Boxes dedicated to each cryogenic subsystem. The ITER cryogenic system will have to cope with various normal and abnormal operational modes including superconducting magnets quench recovery and fast energy discharge. We will present the general Process Flow Diagram of the cryoplant and cryodistribution system and the operation requirements. The functional analysis of the cryogenic system will be performed leading to a proposal of the cryogenic control system architecture. The instrumentation and control requirements will also be outlined.

Henry, D.; Chalifour, M.; Forgeas, A.; Kalinin, V.; Monneret, E.; Serio, L.; Vincent, G.; Voigt, T.

2010-04-01

80

Process optimization of templated DSA flows  

Science.gov (United States)

Directed Self-Assembly (DSA) of Block Co-Polymers (BCP) has become an intense field of study as a potential patterning solution for future generation devices. The most critical challenges that need to be understood and controlled include pattern placement accuracy, achieving low defectivity in DSA patterns and how to make chip designs DSA-friendly. The DSA program at imec includes efforts on these three major topics. Specifically, in this paper the progress in setting up flows for templated DSA within the imec program will be discussed. A process has been implemented based on a hard mask as the template layer. In this paper primarily the impact of local pattern density and BCP film thickness on the templated DSA process are discussed. The open hole rate and the placement accuracy of BCP patterns within the template are the primary figures of merit.

Gronheid, Roel; Bekaert, Joost; Murugesan Kuppuswamy, Vijaya-Kumar; Vandenbroeck, Nadia; Doise, Jan; Cao, Yi; Lin, Guanyang; Sayan, Safak; Parnell, Doni; Somervell, Mark

2014-03-01

81

Automation of Feynman diagram evaluations  

International Nuclear Information System (INIS)

A C-program DIANA (DIagram ANAlyser) for the automation of Feynman diagram evaluations is presented. It consists of two parts: the analyzer of diagrams and the interpreter of a special text manipulating language. This language can be used to create a source code for analytical or numerical evaluations and to keep the control of the process in general

82

Phase diagram effects in rapid thermal processing of REBa2Cu3O7-?  

International Nuclear Information System (INIS)

Recent investigations of rapid thermal processing of REBa2Cu3O7-? by drop tube melting, laser surface treatment and shock compaction have shown that the microstructure resulting from these processes is a complex mixture of non-equilibrium phases. While it is tempting to ascribe the variations in microstructure to variations in quench rates between the processes, we will demonstrate that with the exception of extremely rapid solidification from above the liquidus, the microstructure and phase distribution results from the heating rather than the cooling part of the curve. Since all of the above processes induce non-uniform heating, different parts of the sample reach different maximum temperatures. The maximum temperature reached, and the time spent near that maximum, uniquely determine the starting state of the quench. If the entire sample is not above the liquidus the sluggishness of the peritectic reactions results in similar microstructure regardless of the quench rate. Upon annealing the final microstructure is much more dependent on the number of nucleation sites than on the type of site resulting in a uniform REBa2Cu3O7-? microstructure over a broad range of processing parameters

83

Application of ISO22000, failure mode, and effect analysis (FMEA) cause and effect diagrams and pareto in conjunction with HACCP and risk assessment for processing of pastry products.  

Science.gov (United States)

The Failure Mode and Effect Analysis (FMEA) model has been applied for the risk assessment of pastry processing. A tentative approach of FMEA application to the pastry industry was attempted in conjunction with ISO22000. Preliminary Hazard Analysis was used to analyze and predict the occurring failure modes in a food chain system (pastry processing plant), based on the functions, characteristics, and/or interactions of the ingredients or the processes, upon which the system depends. Critical Control points have been identified and implemented in the cause and effect diagram (also known as Ishikawa, tree diagram, and fishbone diagram). In this work a comparison of ISO22000 analysis with HACCP is carried out over pastry processing and packaging. However, the main emphasis was put on the quantification of risk assessment by determining the Risk Priority Number (RPN) per identified processing hazard. Storage of raw materials and storage of final products at -18°C followed by freezing were the processes identified as the ones with the highest RPN (225, 225, and 144 respectively) and corrective actions were undertaken. Following the application of corrective actions, a second calculation of RPN values was carried out leading to considerably lower values (below the upper acceptable limit of 130). It is noteworthy that the application of Ishikawa (Cause and Effect or Tree diagram) led to converging results thus corroborating the validity of conclusions derived from risk assessment and FMEA. Therefore, the incorporation of FMEA analysis within the ISO22000 system of a pastry processing industry is considered imperative. PMID:21838557

Varzakas, Theodoros H

2011-09-01

84

On Class Diagrams, Crossings and Metrics  

OpenAIRE

As a standardized software engineering diagram, the UML class diagram provides various information on the static structure of views on software while design, implementation and maintenance phase. This talk gives an overview on drawing UML class diagrams in hierarchical fashion. Therefore, common elements of class diagrams are introduced and aesthetic rules for drawing UML class diagrams are given. These rules are based on four disciplines involved in the reading process of diagrams. After...

Eichelberger, Holger

2006-01-01

85

Comparison of microstructural evolution associated with the stress-strain diagrams for nickel and 304 stainless steel: an electron microscope study of microyielding and plastic flow  

International Nuclear Information System (INIS)

The microstructures attendant to specific peak strains along the strain axis of the stress-strain diagram for type 304-stainless steel and nickel have been examined and compared by transmission electron microscopy from epsilon = 0.05% to epsilon 55% in the former and from epsilon = 0.05% to epsilon = 35% in the latter. The onset of flow is characterised by the emission of dislocations from grain boundary ledge sources which form emission profiles resembling dislocation pile-ups in the stainless steel, and a random distribution of dislocations with evidence for very short emission profiles near the grain boundaries in nickel. The results are presented and discussed. (author)

86

Asymmetric exclusion process with next-nearest-neighbor interaction: Some comments on traffic flow and a nonequilibrium reentrance transition  

Science.gov (United States)

We study the steady-state behavior of a driven nonequilibrium lattice gas of hard-core particles with next-nearest-neighbor interaction. We calculate the exact stationary distribution of the periodic system and for a particular line in the phase diagram of the system with open boundaries where particles can enter and leave the system. For repulsive interactions the dynamics can be interpreted as a two-speed model for traffic flow. The exact stationary distribution of the periodic continuous-time system turns out to coincide with that of the asymmetric exclusion process (ASEP) with discrete-time parallel update. However, unlike in the (single-speed) ASEP, the exact flow diagram for the two-speed model resembles in some important features the flow diagram of real traffic. The stationary phase diagram of the open system obtained from Monte Carlo simulations can be understood in terms of a shock moving through the system and an overfeeding effect at the boundaries, thus confirming theoretical predictions of a recently developed general theory of boundary-induced phase transitions. In the case of attractive interaction we observe an unexpected reentrance transition due to boundary effects.

Antal, T.; Schütz, G. M.

2000-07-01

87

Asymmetric exclusion process with next-nearest-neighbor interaction some comments on traffic flow and a nonequilibrium reentrance transition  

CERN Document Server

We study the steady-state behavior of a driven non-equilibrium lattice gas of hard-core particles with next-nearest-neighbor interaction. We calculate the exact stationary distribution of the periodic system and for a particular line in the phase diagram of the system with open boundaries where particles can enter and leave the system. For repulsive interactions the dynamics can be interpreted as a two-speed model for traffic flow. The exact stationary distribution of the periodic continuous-time system turns out to coincide with that of the asymmetric exclusion process (ASEP) with discrete-time parallel update. However, unlike in the (single-speed) ASEP, the exact flow diagram for the two-speed model resembles in some important features the flow diagram of real traffic. The stationary phase diagram of the open system obtained from Monte Carlo simulations can be understood in terms of a shock moving through the system and an overfeeding effect at the boundaries, thus confirming theoretical predictions of a re...

Antal, T

2000-01-01

88

Biological processes, properties and molecular wiring diagrams of candidate low-penetrance breast cancer susceptibility genes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Recent advances in whole-genome association studies (WGASs for human cancer risk are beginning to provide the part lists of low-penetrance susceptibility genes. However, statistical analysis in these studies is complicated by the vast number of genetic variants examined and the weak effects observed, as a result of which constraints must be incorporated into the study design and analytical approach. In this scenario, biological attributes beyond the adjusted statistics generally receive little attention and, more importantly, the fundamental biological characteristics of low-penetrance susceptibility genes have yet to be determined. Methods We applied an integrative approach for identifying candidate low-penetrance breast cancer susceptibility genes, their characteristics and molecular networks through the analysis of diverse sources of biological evidence. Results First, examination of the distribution of Gene Ontology terms in ordered WGAS results identified asymmetrical distribution of Cell Communication and Cell Death processes linked to risk. Second, analysis of 11 different types of molecular or functional relationships in genomic and proteomic data sets defined the "omic" properties of candidate genes: i/ differential expression in tumors relative to normal tissue; ii/ somatic genomic copy number changes correlating with gene expression levels; iii/ differentially expressed across age at diagnosis; and iv/ expression changes after BRCA1 perturbation. Finally, network modeling of the effects of variants on germline gene expression showed higher connectivity than expected by chance between novel candidates and with known susceptibility genes, which supports functional relationships and provides mechanistic hypotheses of risk. Conclusion This study proposes that cell communication and cell death are major biological processes perturbed in risk of breast cancer conferred by low-penetrance variants, and defines the common omic properties, molecular interactions and possible functional effects of candidate genes and proteins.

Moreno Víctor

2008-12-01

89

Hanford Site Treated Effluent Disposal Facility process flow sheet  

International Nuclear Information System (INIS)

This report presents a novel method of using precipitation, destruction and recycle factors to prepare a process flow sheet. The 300 Area Treated Effluent Disposal Facility (TEDF) will treat process sewer waste water from the 300 Area of the Hanford Site, located near Richland, Washington, and discharge a permittable effluent flow into the Columbia River. When completed and operating, the TEDF effluent water flow will meet or exceed water quality standards for the 300 Area process sewer effluents. A preliminary safety analysis document (PSAD), a preconstruction requirement, needed a process flow sheet detailing the concentrations of radionuclides, inorganics and organics throughout the process, including the effluents, and providing estimates of stream flow quantities, activities, composition, and properties (i.e. temperature, pressure, specific gravity, pH and heat transfer rates). As the facility begins to operate, data from process samples can be used to provide better estimates of the factors, the factors can be entered into the flow sheet and the flow sheet will estimate more accurate steady state concentrations for the components. This report shows how the factors were developed and how they were used in developing a flow sheet to estimate component concentrations for the process flows. The report concludes with how TEDF sample data can improve the ability of the flow sheet to accurately predict concentrations of components in the process

90

Fluid flow for chemical and process engineers  

CERN Document Server

This major new edition of a popular undergraduate text covers topics of interest to chemical engineers taking courses on fluid flow. These topics include non-Newtonian flow, gas-liquid two-phase flow, pumping and mixing. It expands on the explanations of principles given in the first edition and is more self-contained. Two strong features of the first edition were the extensive derivation of equations and worked examples to illustrate calculation procedures. These have been retained. A new extended introductory chapter has been provided to give the student a thorough basis to understand the methods covered in subsequent chapters.

Holland, F

1995-01-01

91

Null flows, positive flows and the structure of stationary symmetric stable processes  

OpenAIRE

This paper elucidates the connection between stationary symmetric alpha-stable processes with 0flows on measure spaces by describing a new and unique decomposition of stationary stable processes into those corresponding to positive flows and those corresponding to null flows. We show that a necessary and sufficient for a stationary stable process to be ergodic is that its positive component vanishes.

Samorodnitsky, Gennady

2004-01-01

92

Flow processes in electric discharge drivers  

Science.gov (United States)

The performance of an electric discharge shock tube is discussed from the point of view that the conditions at the sonic station are the primary controlling variables (likewise in comparing designs), and that the analysis of the flow on either side of the sonic station should be done separately. The importance of considering mass-flow rate in matching a given driver design to the downstream flow required for a particular shock-wave speed is stressed. It is shown that a driver based on the principle of liquid injection (of H2) is superior to one based on the Ludwieg tube, because of the greater mass-flow rate and the absence of a massive diaphragm.

Baganoff, D.

1975-01-01

93

OVERLAND FLOW TREATMENT OF POULTRY PROCESSING WASTEWATER IN COLD CLIMATES  

Science.gov (United States)

This project evaluates a full-scale wastewater treatment facility emphasizing the overland flow process in northern Indiana, which has a cold climate. The other processes include mechanical pretreatment, a storage lagoon, a lagoon for batch chemical treatment of the overland flow...

94

Control Flow Pattern Recognition for BPMN Process Models  

Directory of Open Access Journals (Sweden)

Full Text Available Business process modeling is the first and the most important task in business process management (BPM. Business process models are implicitly composed of a set of control flow patterns, such as the Parallel Split, Synchronization, Exclusive Choice, and Simple Merge, etc. Several studies have proposed the concepts and definitions of control flow patterns. But, few analyzed the structure of process models to identify the constituent control flow patterns. This research proposes a three-phased framework to recognize the constituent control flow patterns and their interrelationship for a Business Process Modeling Notation (BPMN process model. The conceptual phase first describes the conceptual process for identifying the control flow patterns from a process model. The design phase then develops the detailed procedure and methods based on the proposed conceptual process to recognize the control flow patterns for a BPMN process model. Finally, the implementation phase carries out the proposed procedure and methods by developing a workflow pattern representation system for BPMN process models.

Yeh-Chun Juan

2013-06-01

95

Phase diagrams  

International Nuclear Information System (INIS)

The description is presented of binary phase diagrams of titanium alloyed with the following elements: silver, aluminium, arsenic, gold, boron, barium, beryllium, bismuth, carbon, calcium, cadmium, cobalt, chromium, copper, iron, gallium, germanium, hydrogen, hafnium, indium, iridium, potassium, lithium, magnesium, manganese, molybdenum, nitrogen, sodium, niobium, nickel, oxygen, osmium, phosphorus, lead, palladium, platinum, plutonium, rhenium, lanthanium, cerium, preseodymium, neodymium, gadolinium, erbium, terbium, thulium, lutetium, rhodium, ruthenium, scandium, silicon, tin, strontium, tantalum, technetium, thorium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc and zirconium

96

Processes | Special Issue : Design and Engineering of Microreactor and Smart-Scaled Flow Processes  

SCPinfonet

... Volker Hessel Micro Flow Chemistry and Process Technology, Department of Chemical Engineering and Chemistry, Technische Universiteit Eindhoven, P. O....nl Phone: +31 40 247 2973 Interests: micro process technology; flow chemistry; process intensification; green processing; holistic evaluation; flow systems engineering; life ... In the last years, micro process technology was not only used for the very problematic synthetic issues which formerly had a dead-end position ... The same holds for the combination of reactions and separations in micro-flow. To achieve throughputs relevant for industrial production, smart scale-out ...

97

The story of Feynman diagrams  

International Nuclear Information System (INIS)

Physicists are no strangers to Feynman diagrams, but the meaning of the diagrams is not always clear, even to those who have used them. That confusion has deep roots, as Kaiser clearly and convincingly explains. To Feynman himself, a diagram depicted an actual physical process in space-time, such as the exchange of photons that occurs when an electron and proton collide. However, he also saw it as shorthand for the contributions to the amplitude of a physical process made by the element of the process it depicted. The best part of this new book covers the early history, social history and 'conceptual history' of Feynman diagrams. Disagreements and criticisms aside, the book will be invaluable to historians and sociologists of physics interested in the growth of Feynman diagrams. (U.K.)

98

Impact of flow velocity on biochemical processes – a laboratory experiment  

OpenAIRE

Understanding and predicting hydraulic and chemical properties of natural environments are current crucial challenges. It requires considering hydraulic, chemical and biological processes and evaluating how hydrodynamic properties impact on biochemical reactions. In this context, an original laboratory experiment to study the impact of flow velocity on biochemical reactions along a one-dimensional flow streamline has been developed. Based on the example of n...

Boisson, A.; Roubinet, D.; Aquilina, L.; Bour, O.; Davy, P.

2014-01-01

99

Stochastic flows with interaction and measure-valued processes  

OpenAIRE

We consider the new class of the Markov measure-valued stochastic processes with constant mass. We give the construction of such processes with the family of the probabilities which describe the motion of single particles. We also consider examples related to stochastic flows with the interactions and the local times for such processes.

Dorogovtsev, Andrey A.

2003-01-01

100

Phase Diagram  

Science.gov (United States)

The thermodynamics of several aspects of the carbothermic reduction of alumina have been examined. In Part I, the results of measuring the evolved CO from the reaction between Al2O3 and C mixtures were used to determine the temperature and carbon contents for carbide formation at alumina saturation and at carbide saturation in the Al2O3-Al4C3 system. In this part of the paper, results are presented for a thermogravimetric study of the reactions of Al2O3 with carbon, as well as those for the determination of the Al2O3 liquidus line and the Al2O3-Al4O4C eutectic in the Al2O3-Al4C3 phase diagram. The critical temperature for Al2O3 and C to react, producing gas at 1 atm., was in agreement with that predicted from thermodynamics and measured in Part I of this paper. However, the Al2O3 liquidus appeared to be steeper and the eutectic temperature lower than the predicted phase diagram.

Walker, Matthew S.; Fruehan, Richard J.

2014-08-01

101

Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005  

Science.gov (United States)

This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by modifying horizontal conductances assembled by the Block-Centered Flow (BCF), Layer-Property Flow (LPF), or Hydrogeologic-Unit Flow Packages (HUF) of MODFLOW-2005. For both conduit flow pipes (CFPM1) and preferential flow layers (CFPM2), critical Reynolds numbers are used to determine if flow is laminar or turbulent. Due to conservation of momentum, flow in a laminar state tends to remain laminar and flow in a turbulent state tends to remain turbulent. This delayed transition between laminar and turbulent flow is introduced in the CFP, which provides an additional benefit of facilitating convergence of the computer algorithm during iterations of transient simulations. Specifically, the user can specify a higher critical Reynolds number to determine when laminar flow within a pipe converts to turbulent flow, and a lower critical Reynolds number for determining when a pipe with turbulent flow switches to laminar flow. With CFPM1, the Hagen-Poiseuille equation is used for laminar flow conditions and the Darcy-Weisbach equation is applied to turbulent flow conditions. With CFPM2, turbulent flow is approximated by reducing the laminar hydraulic conductivity by a nonlinear function of the Reynolds number, once the critical head difference is exceeded. This adjustment approximates the reductions in mean velocity under turbulent ground-water flow conditions.

Shoemaker, W. Barclay; Kuniansky, Eve L.; Birk, Steffen; Bauer, Sebastian; Swain, Eric D.

2007-01-01

102

A multi-phase flow model for electrospinning process  

Directory of Open Access Journals (Sweden)

Full Text Available An electrospinning process is a multi-phase and multi-physicical process with flow, electric and magnetic fields coupled together. This paper deals with establishing a multi-phase model for numerical study and explains how to prepare for nanofibers and nanoporous materials. The model provides with a powerful tool to controlling over electrospinning parameters such as voltage, flow rate, and others.

Xu Lan

2013-01-01

103

Information systems for material flow management in construction processes  

Science.gov (United States)

The article describes the options for the management of material flows in the construction process. Management and resource planning is one of the key factors influencing the effectiveness of construction project. It is very difficult to set these flows correctly. The current period offers several options and tools to do this. Information systems and their modules can be used just for the management of materials in the construction process.

Mesároš, P.; Mandi?ák, T.

2015-01-01

104

Space Based Multi-level Process Flow and Logistics Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available In order to thoroughly promote the enterprise digital construction and meet the demand of production management, the space based multi-level process data organization model has been put forward. Firstly, according to the practical division situation of enterprise production space, the multi-level organization method of production space has been proposed. Then through analyzing the manufacturing process of the products in different space layers, the space based multi-level process flow idea has been presented. At the same time, the mathematical model and formalized expression of multi-level technological process have been established. Finally, the in-output material flow relationship between different levels process flow units has been analyzed and the source of input object as well as the disposition of the output object of various level process flow units has been put into detailed analysis. At the mean time, particular statistical sum and trace arithmetic are provided so as to profoundly illustrate the essence of manufacturing process in theory. As a result, the models proposed in this study are not only express the manufacturing process flow of the product in an intuitive and clear way, but also satisfy all types of demands of production management.

Zhou Qiu-Zhong

2013-01-01

105

Simulation of Flow Fluid in the BOF Steelmaking Process  

Science.gov (United States)

The basic oxygen furnace (BOF) smelting process consists of different chemical reactions among oxygen, slag, and molten steel, which engenders a vigorous stirring process to promote slagging, dephosphorization, decarbonization, heating of molten steel, and homogenization of steel composition and temperature. Therefore, the oxygen flow rate, lance height, and slag thickness vary during the smelting process. This simulation demonstrated a three-dimensional mathematical model for a 100 t converter applying four-hole supersonic oxygen lance and simulated the effect of oxygen flow rate, lance height, and slag thickness on the flow of molten bath. It is found that as the oxygen flow rate increases, the impact area and depth increases, which increases the flow speed in the molten bath and decreases the area of dead zone. Low oxygen lance height benefits the increase of impact depth and accelerates the flow speed of liquid steel on the surface of the bath, while high oxygen lance height benefits the increase of impact area, thereafter enhances the uniform distribution of radial velocity in the molten steel and increases the flow velocity of molten steel at the bottom of furnace hearth. As the slag thickness increases, the diameter of impinging cavity on the slag and steel surface decreases. The radial velocity of liquid steel in the molten bath is well distributed when the jet flow impact on the slag layer increases.

Lv, Ming; Zhu, Rong; Guo, Ya-Guang; Wang, Yong-Wei

2013-12-01

106

DESIGN MODEL FOR THE OVERLAND FLOW PROCESS  

Science.gov (United States)

A design model in the 'Process Design Manual, Land Treatment of Municipal Wastewater' was verified as to removal of biochemical oxygen demand (BOD) and further developed to include removal of total suspended solids, ammonia, and total organic carbon by this field investigation. T...

107

Accurate, reliable control of process gases by mass flow controllers  

Energy Technology Data Exchange (ETDEWEB)

The thermal mass flow controller, or MFC, has become an instrument of choice for the monitoring and controlling of process gas flow throughout the materials processing industry. These MFCs are used on CVD processes, etching tools, and furnaces and, within the semiconductor industry, are used on 70% of the processing tools. Reliability and accuracy are major concerns for the users of the MFCs. Calibration and characterization technologies for the development and implementation of mass flow devices are described. A test facility is available to industry and universities to test and develop gas floe sensors and controllers and evaluate their performance related to environmental effects, reliability, reproducibility, and accuracy. Additional work has been conducted in the area of accuracy. A gravimetric calibrator was invented that allows flow sensors to be calibrated in corrosive, reactive gases to an accuracy of 0.3% of reading, at least an order of magnitude better than previously possible. Although MFCs are typically specified with accuracies of 1% of full scale, MFCs may often be implemented with unwarranted confidence due to the conventional use of surrogate gas factors. Surrogate gas factors are corrections applied to process flow indications when an MFC has been calibrated on a laboratory-safe surrogate gas, but is actually used on a toxic, or corrosive process gas. Previous studies have indicated that the use of these factors may cause process flow errors of typically 10%, but possibly as great as 40% of full scale. This paper will present possible sources of error in MFC process gas flow monitoring and control, and will present an overview of corrective measures which may be implemented with MFC use to significantly reduce these sources of error.

Hardy, J.; McKnight, T.

1997-02-01

108

Automatic Test case Generation from UML Activity Diagrams  

Directory of Open Access Journals (Sweden)

Full Text Available Test Case Generation is an important phase in software development. Nowadays much of the research is done on UML diagrams for generating test cases. Activity diagrams are different from flow diagrams in the fact that activity diagrams express parallel behavior which flow diagrams cannot express. This paper concentrates on UML 2.0 Activity Diagram for generating test cases. Fork and join pair in activity diagram are used to represent concurrent activities. A novel method is proposed to generate test case for concurrent and non concurrent activities. Proposed approach details about the importance of concurrent nodes and their execution order in path generation.

V.Mary Sumalatha*1

2014-05-01

109

Self-Sustaining Nonlinear Dynamo Process in Keplerian Shear Flows  

International Nuclear Information System (INIS)

A three-dimensional nonlinear dynamo process is identified in rotating plane Couette flow in the Keplerian regime. It is analogous to the hydrodynamic self-sustaining process in nonrotating shear flows and relies on the magnetorotational instability of a toroidal magnetic field. Steady nonlinear solutions are computed numerically for a wide range of magnetic Reynolds numbers but are restricted to low Reynolds numbers. This process may be important to explain the sustenance of coherent fields and turbulent motions in Keplerian accretion disks, where all its basic ingredients are present

110

A Stability Diagram for Dense Suspensions of Model Colloidal Al2O3-Particles in Shear Flow  

OpenAIRE

In Al2O3 suspensions, depending on the experimental conditions very different microstructures can be found, comprising fluid like suspensions, a repulsive structure, and a clustered microstructure. For technical processing in ceramics, the knowledge of the microstructure is of importance, since it essentially determines the stability of a workpiece to be produced. To enlighten this topic, we investigate these suspensions under shear by means of simulations. We observe cluste...

Hecht, Martin; Harting, Jens; Herrmann, Hans J.

2006-01-01

111

A Conductivity Relationship for Steady-state Unsaturated Flow Processes under Optimal Flow Conditions  

Energy Technology Data Exchange (ETDEWEB)

Optimality principles have been used for investigating physical processes in different areas. This work attempts to apply an optimal principle (that water flow resistance is minimized on global scale) to steady-state unsaturated flow processes. Based on the calculus of variations, we show that under optimal conditions, hydraulic conductivity for steady-state unsaturated flow is proportional to a power function of the magnitude of water flux. This relationship is consistent with an intuitive expectation that for an optimal water flow system, locations where relatively large water fluxes occur should correspond to relatively small resistance (or large conductance). Similar results were also obtained for hydraulic structures in river basins and tree leaves, as reported in other studies. Consistence of this theoretical result with observed fingering-flow behavior in unsaturated soils and an existing model is also demonstrated.

Liu, H. H.

2010-09-15

112

Numerical Modeling of Fluid Flow in the Tape Casting Process  

OpenAIRE

The flow behavior of the fluid in the tape casting process is analyzed. A simple geometry is assumed for running the numerical calculations in ANSYS Fluent and the main parameters are expressed in non-dimensional form. The effect of different values for substrate velocity and pressure force on the flow pattern as well as resultant tape thickness is evaluated. The analysis deals with the case of parallel blades and focuses on the ratio between the present hydrostatic pressure and the magnitude...

Jabbari, Masoud; Hattel, Jesper Henri

2011-01-01

113

Rotating Thermal Flows in Natural and Industrial Processes  

CERN Document Server

Rotating Thermal Flows in Natural and Industrial Processes provides the reader with a systematic description of the different types of thermal convection and flow instabilities in rotating systems, as present in materials, crystal growth, thermal engineering, meteorology, oceanography, geophysics and astrophysics. It expressly shows how the isomorphism between small and large scale phenomena becomes beneficial to the definition and ensuing development of an integrated comprehensive framework.  This allows the reader to understand and assimilate the underlying, quintessential mechanisms w

Lappa, Marcello

2012-01-01

114

OF.CPP : Consistent Packet Processing for OpenFlow  

OpenAIRE

This paper demonstrates a new class of bugs that is likely to occur in enterprise OpenFlow deployments. In particular, step-by-step, reactive establishment of paths can cause network-wide inconsistencies or performance- and space-related inefficiencies. The cause for this behavior is inconsistent packet processing: as the packets travel through the network they do not encounter consistent state at the OpenFlow controller. To mitigate this problem, we propose to use transactional semantics at ...

Peresini, Peter; Kuzniar, Maciej; Vasic, Nedeljko; Canini, Marco; Kostic, Dejan

2013-01-01

115

OF.CPP: Consistent Packet Processing for OpenFlow  

OpenAIRE

This paper demonstrates a new class of bugs that is likely to occur in enterprise OpenFlow deployments. In particular, step-by-step, reactive establishment of paths can cause network-wide inconsistencies or performance- and space-related inefficiencies. The cause for this behavior is inconsistent packet processing: as the packets travel through the network they do not encounter consistent state at the OpenFlow controller. To mitigate this problem, we propose to use transactional semantics at ...

Peresini, Peter; Kuzniar, Maciej; Vasic, Nedeljko; Canini, Marco; Kostic, Dejan

2013-01-01

116

Modeling a novel glass immobilization waste treatment process using flow  

International Nuclear Information System (INIS)

One option for control and disposal of surplus fissile materials is the Glass Material Oxidation and Dissolution System (GMODS), a process developed at ORNL for directly converting Pu-bearing material into a durable high-quality glass waste form. This paper presents a preliminary assessment of the GMODS process flowsheet using FLOW, a chemical process simulator. The simulation showed that the glass chemistry postulated ion the models has acceptable levels of risks

117

A viscous flow analysis for the tip vortex generation process  

Science.gov (United States)

A three dimensional, forward-marching, viscous flow analysis is applied to the tip vortex generation problem. The equations include a streamwise momentum equation, a streamwise vorticity equation, a continuity equation, and a secondary flow stream function equation. The numerical method used combines a consistently split linearized scheme for parabolic equations with a scalar iterative ADI scheme for elliptic equations. The analysis is used to identify the source of the tip vortex generation process, as well as to obtain detailed flow results for a rectangular planform wing immersed in a high Reynolds number free stream at 6 degree incidence.

Shamroth, S. J.; Briley, W. R.

1979-01-01

118

Arrows in Comprehending and Producing Mechanical Diagrams  

Science.gov (United States)

Mechanical systems have structural organizations--parts, and their relations--and functional organizations--temporal, dynamic, and causal processes--which can be explained using text or diagrams. Two experiments illustrate the role of arrows in diagrams of mechanical systems. In Experiment 1, people described diagrams with or without arrows,…

Heiser, Julie; Tversky, Barbara

2006-01-01

119

IGDS/TRAP Interface Program (ITIP). Detailed Design Specification (DDS). [network flow diagrams for coal gasification studies  

Science.gov (United States)

The software modules which comprise the IGDS/TRAP Interface Program are described. A hierarchical input processing output (HIPO) chart for each user command is given. The description consists of: (1) function of the user command; (2) calling sequence; (3) moduls which call this use command; (4) modules called by this user command; (5) IGDS commands used by this user command; and (6) local usage of global registers. Each HIPO contains the principal functions performed within the module. Also included with each function are a list of the inputs which may be required to perform the function and a list of the outputs which may be created as a result of performing the function.

Jefferys, S.; Johnson, W.; Lewis, R.; Rich, R.

1981-01-01

120

29 CFR 1910.119 - Process safety management of highly hazardous chemicals.  

Science.gov (United States)

...more complex and will show all main flow streams including valves...along with key utilities on process flow diagrams. Piping and instrument...technical reports on topics such as two phase flow for venting devices. This...

2010-07-01

121

29 CFR 1926.64 - Process safety management of highly hazardous chemicals.  

Science.gov (United States)

...more complex and will show all main flow streams including valves...along with key utilities on process flow diagrams. Piping and instrument...technical reports on topics such as two phase flow for venting devices. This...

2010-07-01

122

Flow manipulation and control methodologies for vacuum infusion processes  

Science.gov (United States)

Vacuum Infusion Processes (VIPs) are very attractive composite manufacturing processes since large structures such as fuselages and wind blades can be fabricated in a cost effective manner. In VIPs, the fabric layers are placed on a one sided mold which is closed by enveloping the entire mold with a thin plastic film and evacuating the air out. The vacuum compresses the fabric and when a resin inlet is opened, resin flows into the mold. The resin is allowed to cure before demolding the structure. However, VIPs causes non-repeatable and problematic resin filling patterns due to the heterogeneous nature of the material, nesting between various layers, and the hand labor utilized for laying up the fabric. The design of the manufacturing process routinely involves a trial and error model which make manufacturing costs and development time difficult to estimate. The clear solution to improving the reliability and robustness of VIPs is to implement a system capable of on-line flow control. While on-line flow control has been studied and developed for other composite manufacturing processes, the VIPs have been largely ignored as there are few process parameters that lend themselves to effective flow control. In this work, two new processes were discovered with the goal of on-line control of VIPs in mind. These two processes referred to as Flow Flooding Chamber (FFC) and Vacuum Induced Preform Relaxation (VIPR) will be discussed. They both employ an external vacuum chamber to influence the permeability of the fabric temporarily which allows one to redirect the resin flow to resin starved regions of the mold. The VIPR process in addition uses a low and regulated vacuum pressure in the external chamber to increase the permeability of the fabric in a controllable manner. The objective is to understand how the VIPR process affects the resin flow in order to implement it into a complete flow control and automated environment which will reduce or eliminate the variability experienced. First, the effect on permeability is characterized, so the process can be simulated and the flow front patterns can be predicted. It was found that using the VIPR process in combination with tool side injection gates is a very effective method to control resin flow. Based on this understanding several control algorithms were developed to use the process in an automated manufacturing environment which were tested and validated in a virtual environment. To implement and demonstrate the approach, an experimental workstation was built and various infusion examples were performed in the automated environment to validate the capability of the VIPR process with the control methodologies. The VIPR process with control consistently performed better than the process without control. This contribution should prove useful in making VIPs more reliable in the production of large scale composite structures.

Alms, Justin B.

123

Jamming phase diagram for frictional particles.  

Science.gov (United States)

We investigate the jamming transition of frictional particulate systems via discrete element simulations, reporting the existence of new regimes, which are conveniently described in a jamming phase diagram with axes density, shear stress, and friction coefficient. The resulting jammed states are characterized by different mechanical and structural properties and appear not to be "fragile" as speculated. In particular, we find a regime, characterized by extremely long processes, with a diverging time scale, whereby a suspension first flows but then suddenly jams. We link this sudden jamming transition to the presence of impeded dilatancy. PMID:22181136

Ciamarra, Massimo Pica; Pastore, Raffaele; Nicodemi, Mario; Coniglio, Antonio

2011-10-01

124

Elements of flow and diffusion processes in separation nozzles  

International Nuclear Information System (INIS)

The present monograph is an attempt to systematize the results of studies performed by the author and his colleagues on the physics of the separation nozzle process, which is based on pressure diffusion in curved flows of uranium hexafluoride and a light auxiliary gas. The description of the complex flow and diffusion in separation nozzles includes transient separation effects in ternary mixtures of gases, as well as non-equilibrium phenomena typical of low-density flows of disparate mass mixtures. In addition, the principles and designs of the most important types of separation nozzles are explained in detail. In view of the practical application of the separation nozzle process, general correlations are pointed out between the physics of aerodynamic separation and the technical expenditure for large-scale production of enriched uranium. (orig./WL)

125

Coaching, lean processes and the concept of flow  

DEFF Research Database (Denmark)

The chapter takes us inside Nordea Bank to look at how coaching was used to support their leadership development as they underwent a major change effort implementation. Drawing on the literature on Lean processes, flow and coaching, it demonstrates some of the challenges and opportunities of working with coaching in a systematic way across broader initiatives in organizations.

Skytte GØrtz, Kim Erik

2008-01-01

126

Impact of flow velocity on biochemical processes - a laboratory experiment  

Science.gov (United States)

Understanding and predicting hydraulic and chemical properties of natural environments are current crucial challenges. It requires considering hydraulic, chemical and biological processes and evaluating how hydrodynamic properties impact on biochemical reactions. In this context, an original laboratory experiment to study the impact of flow velocity on biochemical reactions along a one-dimensional flow streamline has been developed. Based on the example of nitrate reduction, nitrate-rich water passes through plastic tubes at several flow velocities (from 6.2 to 35 mm min-1), while nitrate concentration at the tube outlet is monitored for more than 500 h. This experimental setup allows assessing the biologically controlled reaction between a mobile electron acceptor (nitrate) and an electron donor (carbon) coming from an immobile phase (tube) that produces carbon during its degradation by microorganisms. It results in observing a dynamic of the nitrate transformation associated with biofilm development which is flow-velocity dependent. It is proposed that the main behaviors of the reaction rates are related to phases of biofilm development through a simple analytical model including assimilation. Experiment results and their interpretation demonstrate a significant impact of flow velocity on reaction performance and stability and highlight the relevance of dynamic experiments over static experiments for understanding biogeochemical processes.

Boisson, A.; Roubinet, D.; Aquilina, L.; Bour, O.; Davy, P.

2014-08-01

127

Impact of flow velocity on biochemical processes – a laboratory experiment  

Directory of Open Access Journals (Sweden)

Full Text Available Understanding and predicting hydraulic and chemical properties of natural environments are current crucial challenges. It requires considering hydraulic, chemical and biological processes and evaluating how hydrodynamic properties impact on biochemical reactions. In this context, an original laboratory experiment to study the impact of flow velocity on biochemical reactions along a one-dimensional flow streamline has been developed. Based on the example of nitrate reduction, nitrate-rich water passes through plastic tubes at several flow velocities (from 6.2 to 35 mm min?1, while nitrate concentration at the tube outlet is monitored for more than 500 h. This experimental setup allows assessing the biologically controlled reaction between a mobile electron acceptor (nitrate and an electron donor (carbon coming from an immobile phase (tube that produces carbon during its degradation by microorganisms. It results in observing a dynamic of the nitrate transformation associated with biofilm development which is flow-velocity dependent. It is proposed that the main behaviors of the reaction rates are related to phases of biofilm development through a simple analytical model including assimilation. Experiment results and their interpretation demonstrate a significant impact of flow velocity on reaction performance and stability and highlight the relevance of dynamic experiments over static experiments for understanding biogeochemical processes.

A. Boisson

2014-08-01

128

Flows of engineered nanomaterials through the recycling process in Switzerland.  

Science.gov (United States)

The use of engineered nanomaterials (ENMs) in diverse applications has increased during the last years and this will likely continue in the near future. As the number of applications increase, more and more waste with nanomaterials will be generated. A portion of this waste will enter the recycling system, for example, in electronic products, textiles and construction materials. The fate of these materials during and after the waste management and recycling operations is poorly understood. The aim of this work is to model the flows of nano-TiO2, nano-ZnO, nano-Ag and CNT in the recycling system in Switzerland. The basis for this study is published information on the ENMs flows on the Swiss system. We developed a method to assess their flow after recycling. To incorporate the uncertainties inherent to the limited information available, we applied a probabilistic material flow analysis approach. The results show that the recycling processes does not result in significant further propagation of nanomaterials into new products. Instead, the largest proportion will flow as waste that can subsequently be properly handled in incineration plants or landfills. Smaller fractions of ENMs will be eliminated or end up in materials that are sent abroad to undergo further recovery processes. Only a reduced amount of ENMs will flow back to the productive process of the economy in a limited number of sectors. Overall, the results suggest that risk assessment during recycling should focus on occupational exposure, release of ENMs in landfills and incineration plants, and toxicity assessment in a small number of recycled inputs. PMID:25524750

Caballero-Guzman, Alejandro; Sun, Tianyin; Nowack, Bernd

2015-02-01

129

Phase Diagrams for Traffics on the Crossroad  

Science.gov (United States)

The traffic flows on two one-lane roads, crossing at a point, are studied on the basis of the local occupation probability method. The phase diagrams are constructed for the cases of various maximum car velocities. It has turned out that the phase diagrams consist essentailly of five regions.

Ishibashi, Yoshihiro; Fukui, Minoru

2001-09-01

130

Features, Events, and Processes in UZ Flow and Transport  

International Nuclear Information System (INIS)

Unsaturated zone (UZ) flow and radionuclide transport is a component of the natural barriers that affects potential repository performance. The total system performance assessment (TSPA) model, and underlying process models, of this natural barrier component capture some, but not all, of the associated features, events, and processes (FEPs) as identified in the FEPs Database (Freeze, et al. 2001 [154365]). This analysis and model report (AMR) discusses all FEPs identified as associated with UZ flow and radionuclide transport. The purpose of this analysis is to give a comprehensive summary of all UZ flow and radionuclide transport FEPs and their treatment in, or exclusion from, TSPA models. The scope of this analysis is to provide a summary of the FEPs associated with the UZ flow and radionuclide transport and to provide a reference roadmap to other documentation where detailed discussions of these FEPs, treated explicitly in TSPA models, are offered. Other FEPs may be screened out from treatment in TSPA by direct regulatory exclusion or through arguments concerning low probability and/or low consequence of the FEPs on potential repository performance. Arguments for exclusion of FEPs are presented in this analysis. Exclusion of specific FEPs from the UZ flow and transport models does not necessarily imply that the FEP is excluded from the TSPA. Similarly, in the treatment of included FEPs, only the way in which the FEPs are included in the UZ flow and transport models is discussed in this document. This report has been prepared in accordance with the technical work plan for the unsaturated zone subproduct element (CRWMS MandO 2000 [153447]). The purpose of this report is to document that all FEPs are either included in UZ flow and transport models for TSPA, or can be excluded from UZ flow and transport models for TSPA on the basis of low probability or low consequence. Arguments for exclusion are presented in this analysis. Exclusion of specific FEPs from UZ flow and transport models does not necessarily imply that the FEP is excluded from the TSPA. Similarly, in the treatment of included FEPs, only the way in which FEPs are included in UZ flow and transport models is discussed in this document

131

Features, Events, and Processes in UZ Flow and Transport  

Energy Technology Data Exchange (ETDEWEB)

Unsaturated zone (UZ) flow and radionuclide transport is a component of the natural barriers that affects potential repository performance. The total system performance assessment (TSPA) model, and underlying process models, of this natural barrier component capture some, but not all, of the associated features, events, and processes (FEPs) as identified in the FEPs Database (Freeze, et al. 2001 [154365]). This analysis and model report (AMR) discusses all FEPs identified as associated with UZ flow and radionuclide transport. The purpose of this analysis is to give a comprehensive summary of all UZ flow and radionuclide transport FEPs and their treatment in, or exclusion from, TSPA models. The scope of this analysis is to provide a summary of the FEPs associated with the UZ flow and radionuclide transport and to provide a reference roadmap to other documentation where detailed discussions of these FEPs, treated explicitly in TSPA models, are offered. Other FEPs may be screened out from treatment in TSPA by direct regulatory exclusion or through arguments concerning low probability and/or low consequence of the FEPs on potential repository performance. Arguments for exclusion of FEPs are presented in this analysis. Exclusion of specific FEPs from the UZ flow and transport models does not necessarily imply that the FEP is excluded from the TSPA. Similarly, in the treatment of included FEPs, only the way in which the FEPs are included in the UZ flow and transport models is discussed in this document. This report has been prepared in accordance with the technical work plan for the unsaturated zone subproduct element (CRWMS M&O 2000 [153447]). The purpose of this report is to document that all FEPs are either included in UZ flow and transport models for TSPA, or can be excluded from UZ flow and transport models for TSPA on the basis of low probability or low consequence. Arguments for exclusion are presented in this analysis. Exclusion of specific FEPs from UZ flow and transport models does not necessarily imply that the FEP is excluded from the TSPA. Similarly, in the treatment of included FEPs, only the way in which FEPs are included in UZ flow and transport models is discussed in this document.

J.E. Houseworth

2001-04-10

132

On-line sample processing methods in flow analysis  

DEFF Research Database (Denmark)

In this chapter, the state of the art of flow injection and related approaches thereof for automation and miniaturization of sample processing regardless of the aggregate state of the sample medium is overviewed. The potential of the various generation of flow injection for implementation of in-line dilution, derivatization, separation and preconcentration methods encompassing solid reactors, solvent extraction, sorbent extraction, precipitation/coprecipitation, hydride/vapor generation and digestion/leaching protocols as hyphenated to a plethora of detection devices is discussed in detail and relevant examples published in the literature up to April 2007 are pinpointed.

Miró, Manuel; Hansen, Elo Harald

2008-01-01

133

Calculation of flow and diffusion processes in gas centrifuges  

International Nuclear Information System (INIS)

The calculation of the flow and diffusion processes within high-velocity gas centrifuges is accomplished by numerically solving the rotation-symmetric conservation equations. The flow field, initially assumed to be homogeneous and ideal, is calculated within the realm of continuity by a numerical integration of the transient linear, or alternatively, non-linear Navier-Stokes equations in rotating systems. The solution of the system of equations is conducted by Beam and Warming's implicit non-iterative, cubically factored finite difference algorithm. The physical boundary conditions are implemented both explicitly and implicitly as a result of the improved stability characteristics when applying large temporal increments. (orig./HP)

134

Ground-state phase diagram and magnetization process of the exactly solved mixed spin-(1,1/2) Ising diamond chain  

Energy Technology Data Exchange (ETDEWEB)

The ground state and magnetization process of the mixed spin-(1,1/2) Ising diamond chain are exactly solved by employing the generalized decoration–iteration mapping transformation and the transfer-matrix method. The decoration–iteration transformation is first used in order to establish a rigorous mapping equivalence with the corresponding spin-1 Blume-Emery-Griffiths chain in a non-zero magnetic field, which is subsequently exactly treated within the framework of the transfer-matrix technique. It is shown that the ground-state phase diagram includes just four different ground states and the low-temperature magnetization curve may exhibit an intermediate plateau precisely at one half of the saturation magnetization. Our rigorous results disprove recent Monte Carlo simulations of Xin et al. [Z. Xin, S. Chen, C. Zhang, J. Magn. Magn. Mater. 324 (2012) 3704], which imply an existence of the other magnetization plateaus at 0.283 and 0.426 of the saturation magnetization. - Highlights: • Mixed spin-(1,1/2) Ising diamond chain is exactly solved. • Ground-state phase diagram consists of four different phases. • Magnetization plateaus at zero and half of the saturation magnetization were found.

Lisnyi, Bohdan, E-mail: lisnyj@icmp.lviv.ua [Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia); Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, 79011 L' viv (Ukraine); Stre?ka, Jozef, E-mail: jozef.strecka@upjs.sk [Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia)

2013-11-15

135

Multilevel flow modelling of process plant for diagnosis and control  

International Nuclear Information System (INIS)

The paper describes the multilevel flow modelling methodology which can be used to construct functional models of energy and material processing systems. The models describe mass and energy flow topology on different levels of abstraction and represent the hierarchical functional structure of complex systems. A model of a nuclear power plant (PWR) is presented in the paper for illustration. Due to the consistency of the method, multilevel flow models provide specifications of plant goals and functions and may be used as a basis for design of computer-based support systems for the plant operator. Plant control requirements can be derived from the models and due to independence of the actual controller implementation the method may be used as basic for design of control strategies and for the allocation of control tasks to the computer and the plant operator. (author)

136

Flow processes in the meshed fissure rock model  

International Nuclear Information System (INIS)

Assuming an idealized, schematic form of fissure systems and based on the known laws of fissure flow, the influence of fissure distribution and fissure aperture size on the flow processes in rock has been studied. Based on the assumed parameters of fissures, 40 cases with different fissure geometry have been solved. The computer programme has been developed from an existent programme for meshed pipe networks. By means of some selected examples the most essential results are presented as patterns of potential and flow distribution. The comprehensive interpretation of the model results permits conclusions to be drawn for practical application in groundwater hydrology. The results obtained are of importance, for example in evaluating the effects to be expected as a result of groundwater drawdown in the construction of deep rock excavations or of drawdown due to wells. Conclusions regarding the migration of contaminants and localization of contamination sources may also be drawn. (orig.)

137

The investigate of flow in direct extrusion process of heterogeneous materials flow  

OpenAIRE

The results of experimental investigations were introduced in range of verification of model investigations results (in utilization of supplementary materials) with results of investigations on real materials are presented in this work. To this aim the matrix became constructed with interchangeable little eye made possible extrusion process of real materials at three reduction ratio: ? = 1,5 1,75 and 2,0. Analysis of heterogeneous materials flow process shows, that of principle onto extrusio...

Patejuk, A.; Piwnik, J.; Gabrylewski, M.

2007-01-01

138

Evaluation of the MODFLOW-2005 Conduit Flow Process.  

Science.gov (United States)

The recent development of the Conduit Flow Process (CFP) by the U.S. Geological Survey (USGS) provides hydrogeologic modelers with a new tool that incorporates the non-Darcian, multiporosity components of flow characteristic of karst aquifers. CFP introduces new parameters extending beyond those of traditional Darcian groundwater flow codes. We characterize a karst aquifer to collect data useful for evaluating this new tool at a test site in west-central Florida, where the spatial distribution and cross-sectional area of the conduit network are available. Specifically, we characterize: (1) the potential for Darcian/non-Darcian flow using estimates of specific discharge vs. observed hydraulic gradients, and (2) the temporal variation for the direction and magnitude of fluid exchange between the matrix and conduit network during extreme hydrologic events. We evaluate the performance of CFP Mode 1 using a site-scale dual-porosity model and compare its performance with a comparable laminar equivalent continuum model (ECM) using MODFLOW-2005. Based on our preliminary analyses, hydraulic conductivity coupled with conduit wall conductance improved the match between observed and simulated discharges by 12% to 40% over turbulent flow alone (less than 1%). PMID:20113361

Hill, Melissa E; Stewart, Mark T; Martin, Angel

2010-01-01

139

Recharge and flow processes in a till aquitard  

DEFF Research Database (Denmark)

Eastern Denmark is primarily covered by clay till. The transformation of the excess rainfall into laterally diverted groundwater flow, drain flow, stream flow, and recharge to the underlying aquifer is governed by complicatedinterrelated processes. Distributed hydrological models provide a framework for assessing the individual flow components and forestablishing the overall water balance. Traditionally such models are calibrated against measurements of stream flow, head in the aquiferand perhaps drainage flow. The head in the near surface clay till deposits have generally not been measured and therefore not consideredin the calibration procedure.In a 16 km2 rural catchment, 15 shallow wells were installed in the upstream end for continuous measurements of the fluctuations in hydraulic head. In addition data were obtained from two wells penetrating to the deeper artesian aquifer, one located near the shallow wells and one in the valley adjacent to the stream. Precipitation and stream flow gauging along with potential evaporation estimates from a nearby weather station provide the basic data for the overall water balance assessment. The geological composition was determined from geoelectrical surveys along three transects, supported by geophysical logs in deepwells, lowflow records at the outlet of the catchment and three tributaries, and soil maps. Slug tests were carried to obtain data forhydraulic conductivity.The time series of hydraulic head depth in the shallow wells were analyzed using linear transfer noise functions on driving input timeseries and kriging techniques in order to identify correlation structures in time and space among the wells.The distributed and physically based hydrological model code MIKE SHE was applied to the catchment. The model considers one-dimensional flow in the unsaturated zone and three-dimensional below. Drainage flow isempirically modelled as a linear reservoir using a time constant related to drain pipe capacity, spacing and soil hydraulic conductivity.Key parameters are calibrated against records of precipitation, potential evaporation and stream flow. Simulation based on historicalrecords prior to the installation of subsurface drainage in 1/3 of the catchment was carried out in order to investigate the impact ofdrainage on streamflow and access the use of the linear reservoir assumption. Subsequently, data from the shallow wells wereconsidered in order to analyse the value of such data in the calibration procedure and particularly in estimating the areal variation inrecharge.

SchrØder, Thomas Morville; HØgh Jensen, Karsten

1999-01-01

140

Preface "Nonlinear processes in oceanic and atmospheric flows"  

Directory of Open Access Journals (Sweden)

Full Text Available Nonlinear phenomena are essential ingredients in many oceanic and atmospheric processes, and successful understanding of them benefits from multidisciplinary collaboration between oceanographers, meteorologists, physicists and mathematicians. The present Special Issue on "Nonlinear Processes in Oceanic and Atmospheric Flows" contains selected contributions from attendants to the workshop which, in the above spirit, was held in Castro Urdiales, Spain, in July 2008. Here we summarize the Special Issue contributions, which include papers on the characterization of ocean transport in the Lagrangian and in the Eulerian frameworks, generation and variability of jets and waves, interactions of fluid flow with plankton dynamics or heavy drops, scaling in meteorological fields, and statistical properties of El Niño Southern Oscillation.

E. García-Ladona

2010-05-01

141

Production process flow optimization at Euro-Plastifoam (Pty) Ltd  

OpenAIRE

Various methods, tools and techniques will be applied in order to improve, and ultimately optimize, the production process flow at Euro-Plastifoam. Work measurement will be performed, followed by value stream analysis as well as the application of problem identification methods. This again, will be followed by layout analysis and improvement. Other proposed solutions include the introduction of a Kanban system, 5S House keeping and Single Minute Exchange of Dies (SMED).

Zietsman, Ignatius

2011-01-01

142

Numerical modelling of river processes: flow and river bed deformation  

OpenAIRE

The morphology of alluvial river channels is a consequence of complex interaction among a number of constituent physical processes, such as flow, sediment transport and river bed deformation. This is, an alluvial river channel is formed from its own sediment. From time to time, alluvial river channels are subject to disturbances in their immediate environment caused by natural or artificial effects, namely variable inflow, sediment supply, and various human activities such as channel regul...

Tassi, Pablo

2007-01-01

143

Nonlinear Flow Process: A New Package to Compute Nonlinear Flow in MODFLOW.  

Science.gov (United States)

A new MODFLOW package (Nonlinear Flow Process; NLFP) simulating nonlinear flow following the Forchheimer equation was developed and implemented in MODLFOW-2005. The method is based on an iterative modification of the conductance calculated and used by MODFLOW to obtain an effective Forchheimer conductance. The package is compatible with the different layer types, boundary conditions, and solvers as well as the wetting capability of MODFLOW. The correct implementation is demonstrated using four different benchmark scenarios for which analytical solutions are available. A scenario considering transient flow in a more realistic setting and a larger model domain with a higher number of cells demonstrates that NLFP performs well under more complex conditions, although it converges moderately slower than the standard MODFLOW depending on the nonlinearity of flow. Thus, this new tool opens a field of opportunities to groundwater flow simulation with MODFLOW, especially for core sample simulation or vuggy karstified aquifers as well as for nonlinear flow in the vicinity of pumping wells. PMID:25059312

Mayaud, Cyril; Walker, Patrica; Hergarten, Stefan; Birk, Steffen

2014-07-24

144

Electrochemical analysis on the process of flow accelerated corrosion  

International Nuclear Information System (INIS)

Flow accelerated corrosion behavior concerning both activation and mass transfer process of low alloy steel was studied using rotating cyclinder electrode in room temperature alkaline solution by electrochemical techniques. Passive film was formed pH 9.8 by step oxidation of ferrous product into hydroxyl compound. Corrosion potential shifted slightly upward with rotating velocity through the diffusion of cathodic species. From the analysis between corrosion current and limiting current, there seems that activation process, which represents formation of passive film on the bare metal surface, controls the entire corrosion kinetics

145

Flow effects on benthic stream invertebrates and ecological processes  

Science.gov (United States)

Flow is the main abiotic factor in the streams. Flow affects the organisms in many direct and indirect ways. The organisms are directly affected by various hydrodynamic forces and mass transfer processes like drag forces, drift, shear stress, food and gases supply and washing metabolites away. Indirect effects on the organisms are determining and distribution of the particle size and structure of the substrate and determining the morphology of riverbeds. Flow does not affect only on individual organism, but also on many ecological effects. To expose just the most important: dispersal of the organisms, habitat use, resource acquisition, competition and predator-prey interactions. Stream invertebrates are adapted to the various flow conditions in many kinds of way. Some of them are avoiding the high flow with living in a hyporeic zone, while the others are adapted to flow with physical adaptations (the way of feeding, respiration, osmoregulation and resistance to draught), morphological adaptations (dorsoventrally flattened shape of organism, streamlined shape of organism, heterogeneous suckers, silk, claws, swimming hair, bristles and ballast gravel) or with behaviour. As the flow characteristics in a particular stream vary over a broad range of space and time scales, it is necessary to measure accurately the velocity in places where the organisms are present to determine the actual impact of flow on aquatic organisms. By measuring the mean flow at individual vertical in a single cross-section, we cannot get any information about the velocity situation close to the bottom of the riverbed where the stream invertebrates are living. Just measuring the velocity near the bottom is a major problem, as technologies for measuring the velocity and flow of natural watercourses is not adapted to measure so close to the bottom. New researches in the last two decades has shown that the thickness of laminar border layer of stones in the stream is only a few 100 micrometers, what is not enough to make a shelter for stream invertebrates. It serves as a shelter only for microorganisms, but the stream invertebrates have to avoid the swift flow or adapt to flow with adaptations described above. To understand what conditions are subject to aquatic organisms and how to adapt, it is essential. Both, knowledge of fluid dynamics in natural watercourses and ecology are needed to understand to what conditions the stream invertebrates are exposed and how they cope with them. Some investigations of near bed flow will be performed on the Glinšica stream. The acoustic Doppler velocimeter SonTek will be adapted to measure so close to the bed as possible. It is expected we should be able to measure the velocities just 0,5 cm above the bed surface. We intend to measure the velocities on a natural and on a regulated reach and then compare the results.

Koprivsek, Maja; Brilly, Mitja

2010-05-01

146

Investigation of flow and microstructure in rheometric and processing flow conditions for liquid crystalline pitch  

Science.gov (United States)

The microstructure development within mesophase pitch-based carbon materials depends on the flow history that the pitch is subjected to. Therefore, a fundamental understanding of flow and its influence on the microstructure is required to obtain carbon materials with desired properties. The objective of this research was to investigate the flow and microstructural behavior of a synthetic mesophase pitch (AR-HP) in rheometric and processing flow conditions. In addition, simulation studies were performed to establish a frame work for modeling the flow behavior of this complex material in different flow situations. The steady-shear viscosities obtained from a cone-plate rheometer during increasing rate-sweep experiments exhibited shear-thinning (Region I) and plateau (Region II) responses. However, the slope of the shear-thinning region was only about -0.2, much lower than -0.5 observed in some pitches and liquid-crystalline polymers. This difference could arise from the different molecular constituents of pitches. At higher shear rates, as measured from capillary rheometers, the viscosity values remained almost constant. The transient shear stress responses, as measured from cone-plate rheometer, exhibited nonmonotonic behavior as a function of applied strain at all shear rates and temperatures tested. After rheological experiments, the samples were collected by developing a new experimental protocol for preservation of the sample for microstructural analysis. Microstructural observations obtained from three orthogonal sections, reported for the first time in the literature, indicate that the local maximum in shear stress was due to yielding of initial microstructure. The microstructure became flow oriented with further shearing, and the structure size decreased with increasing shear rates. In addition to high-strain experiments, dynamic experiments were also performed in the linear viscoelastic region where no significant deformation of fluid takes place. The elastic response was found to be strongly dependent on the microstructure, and a lower slope of 0.8 for the elastic modulus in the low-frequency terminal region was observed as compared to 2 observed for flexible chain polymers. Relaxation of microstructure resulted in an increase of storage moduli. However, the relaxation time did not follow the scaling argument, tau ˜ etaa2/ K. It is postulated that the relaxation process is influenced not only by the textural size, but also by layer-plane orientation. The flow-microstructural study was extended to the processing flow conditions and in this case AR-HP mesophase pitch was extruded through custom-made dies using a single-screw extruder. Due to changing dimensions of these dies, the mesophase pitch was subjected to varying shear rates. Microstructural observations suggest that in the capillary region of these dies, the orientation of the layer-plane was approximately radial near the wall. Away from the wall, the deviation of orientation of the layer-planes from the radial direction was significant and some layer-planes were oriented tangentially. In the core, the microstructure was coarse and no preferred orientation of mesophase layerplanes was observed. Simulation studies were performed using constitutive equations for discotic liquid-crystalline materials in simple shear flow, corresponding with the experimental studies. The simulation studies were performed for two different initial conditions that resemble the experimental results. At steady state, the bulk of the discs were found to be oriented at a flow-aligned angle of -64.1°, which is consistent with the theoretical predictions. Although, the simulation studies could not capture the complex microstructure observed experimentally, similarities in flow-aligned domains were observed. This study establishes a frame work to simulate the flow dynamics of complex mesophase pitch in multiscale-mulidimensional problems using the computational facility and expertise of the Center for Advanced Engineering Fibers and Films (CAEFF).

Kundu, Santanu

147

Diagrams and parameters of process heat supply from commercial-heating plants on the base of HTGR reactors  

International Nuclear Information System (INIS)

Comparative analysis of several versions of basic layouts of process heat supply from dual-cycle steam-turbine plants with HTGR reactors is considered. The versions differ in organization of heating steam extraction in steam conversion plants (SCP) and by the ways of using drainage of heating steam. Temperature gradient in evaporator is taken as an optimized parameter. It is shown that design solutions affect slightly the optimized parameter. The decisive effect of the steam transportation distance and the degree of process steam overheating in SCP on efficiency of considered layouts was revealed

148

Do health technology assessments comply with QUOROM diagram guidance? An empirical study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The Quality of Reporting of Meta-analyses (QUOROM statement provides guidance for improving the quality of reporting of systematic reviews and meta-analyses. To make the process of study selection transparent it recommends "a flow diagram providing information about the number of RCTs identified, included, and excluded and the reasons for excluding them". We undertook an empirical study to identify the extent of compliance in the UK Health Technology Assessment (HTA programme. Methods We searched Medline to retrieve all systematic reviews of therapeutic interventions in the HTA monograph series published from 2001 to 2005. Two researchers recorded whether each study contained a meta-analysis of controlled trials, whether a QUOROM flow diagram was presented and, if so, whether it expressed the relationship between the number of citations and the number of studies. We used Cohen's kappa to test inter-rater reliability. Results 87 systematic reviews were retrieved. There was good and excellent inter-rater reliability for, respectively, whether a review contained a meta-analysis and whether each diagram contained a citation-to-study relationship. 49% of systematic reviews used a study selection flow diagram. When only systematic reviews containing a meta-analysis were analysed, compliance was only 32%. Only 20 studies (23% of all systematic reviews; 43% of those having a study selection diagram had a diagram which expressed the relationship between citations and studies. Conclusion Compliance with the recommendations of the QUOROM statement is not universal in systematic reviews or meta-analyses. Flow diagrams make the conduct of study selection transparent only if the relationship between citations and studies is clearly expressed. Reviewers should understand what they are counting: citations, papers, studies and trials are fundamentally different concepts which should not be confused in a diagram.

Booth Andrew

2007-11-01

149

Design flow for implementing image processing in FPGAs  

Science.gov (United States)

A design flow for implementing a dynamic gamma algorithm in an FPGA is described. Real-time video processing makes enormous demands on processing resources. An FPGA solution offers some advantages over commercial video chip and DSP implementation alternatives. The traditional approach to FPGA development involves a system engineer designing, modeling and verifying an algorithm and writing a specification. A hardware engineer uses the specification as a basis for coding in VHDL and testing the algorithm in the FPGA with supporting electronics. This process is work intensive and the verification of the image processing algorithm executing on the FPGA does not occur until late in the program. The described design process allows the system engineer to design and verify a true VHDL version of the algorithm, executing in an FPGA. This process yields reduced risk and development time. The process is achieved by using Xilinx System Generator in conjunction with Simulink® from The MathWorks. System Generator is a tool that bridges the gap between the high level modeling environment and the digital world of the FPGA. System Generator is used to develop the dynamic gamma algorithm for the contrast enhancement of a candidate display product. The results of this effort are to increase the dynamic range of the displayed video, resulting in a more useful image for the user.

Trakalo, M.; Giles, G.

2007-04-01

150

Numerical Modeling of Fluid Flow in the Tape Casting Process  

DEFF Research Database (Denmark)

The flow behavior of the fluid in the tape casting process is analyzed. A simple geometry is assumed for running the numerical calculations in ANSYS Fluent and the main parameters are expressed in non-dimensional form. The effect of different values for substrate velocity and pressure force on the flow pattern as well as resultant tape thickness is evaluated. The analysis deals with the case of parallel blades and focuses on the ratio between the present hydrostatic pressure and the magnitude of the viscous force. A new non-dimensional height for the tape thickness is proposed and the effect of the substrate velocity is evaluated. The results of the modeling show that a relatively uniform tape thickness can be achieved. Moreover, the results are compared with selected experimental and analytical data from literature and good agreement is found.

Jabbari, Masoud; Hattel, Jesper Henri

2011-01-01

151

Coded ultrasound for blood flow estimation using subband processing  

DEFF Research Database (Denmark)

This paper further investigates the use of coded excitation for blood flow estimation in medical ultrasound. Traditional autocorrelation estimators use narrow-band excitation signals to provide sufficient signal-to-noise-ratio (SNR) and velocity estimation performance. In this paper, broadband coded signals are used to increase SNR, followed by sub-band processing. The received broadband signal, is filtered using a set of narrow-band filters. Estimating the velocity in each of the bands and averaging the results yields better performance compared to what would be possible when transmitting a narrow-band pulse directly. Also, the spatial resolution of the narrow-band pulse would be too poor for brightness-mode (B-mode) imaging and additional transmissions would be required to update the B-mode image. In the described approach, there is no need for additional transmissions, because the excitation signal is broadband and has good spatial resolution after pulse compression. Two different codin-schemes are used inthis paper, Barker codes and Golay codes. The performance of the codes for velocity estimation is compared to a conventional approach transmitting a narrow-band pulse. The study was carried out using an experimental ultrasound scanner and a commercial linear array 7 MHz transducer. A circulating flow rig was scanned with a beam-to-flow angle of 60 degrees. The flow in the rig was laminar and had a parabolic flow-profile with a peak velocity of 0.09 m/s. The mean relative standard deviation of the reference method using an eight cycle excitation pulse at 7 MHz was 0.544% compared to the peak velocity in the rig. Two Barker codes were tested with a length of 5 and 13 bits, respectively. The corresponding mean relative standard deviations were 0.367% and 0.310%, respectively. For the Golay coded experiment, two 8 bit codes were used, and the mean relative standard deviation was 0.335%.

Gran, Fredrik; Udesen, Jesper

2007-01-01

152

RANS-based simulation of turbulent wave boundary layer and sheet-flow sediment transport processes  

DEFF Research Database (Denmark)

A numerical model coupling the horizontal component of the incompressible Reynolds-averaged Navier–Stokes (RANS) equationswith two-equation k?? turbulence closure is presented and used to simulate a variety of turbulent wave boundary layer processes. The hydrodynamic model is additionally coupled with bed and suspended load descriptions, the latter based on an unsteady turbulent-diffusion equation, for simulation of sheet-flow sediment transport processes. In addition to standard features common within such RANS-based approaches, the present model includes: (1) hindered settling velocities at high suspended sediment concentrations, (2) turbulence suppression due to density gradients in the water–sand mixture, (3) boundary layer streaming due to convective terms, and (4) converging–diverging effects due to a sloping bed. The present model therefore provides a framework for simultaneous inclusion of a number of local factors important within cross-shore wave boundary layer and sediment transport dynamics. The hydrodynamic model is validated for both hydraulically smooth and rough conditions, based on wave friction factor diagrams and boundary layer streaming profiles, with the results in excellent agreement with experimental and/or previous numerical work. The sediment transport model is likewise validated against oscillatory tunnel experiments involving both velocity-skewed and acceleration-skewed flows, as well as against measurements beneath real progressive waves.Model capabilities are exploited to investigate the importance of boundary layer streaming effects on sediment transport in selected velocity-skewed conditions. For the medium sand grain conditions considered, the model results suggest that streaming effects can enhance onshore sediment transport rates by asmuch as a factor of two.Moreover, for fine sand conditions streaming (and related convective) effects are demonstrated to potentially reverse the direction of net transport (i.e. from offshore to onshore) relative that predicted in oscillatory tunnel conditions. The developed model is implemented within the popular Matlab environment, and hence may be attractive for both research and educational purposes.

Fuhrman, David R.; SchlØer, Signe

2013-01-01

153

Post-processing methods of PIV instantaneous flow fields for unsteady flows in turbomachines  

OpenAIRE

The Particle Image Velocimetry is undoubtedly one of the most important technique in Fluid-dynamics since it allows to obtain a direct and instantaneous visualization of the flow field in a non-intrusive way. This innovative technique spreads in a wide number of research fields, from aerodynamics to medicine, from biology to turbulence researches, from aerodynamics to combustion processes. The book is aimed at presenting the PIV technique and its wide range of possible applications so as to p...

Cavazzini, Giovanna; Dazin, Antoine; Pavesi, Giorgio; Dupont, Patrick; Bois, Ge?rard

2012-01-01

154

Extrinsic Curvature Embedding Diagrams  

CERN Document Server

Embedding diagrams have been used extensively to visualize the properties of curved space in Relativity. We introduce a new kind of embedding diagram based on the {\\it extrinsic} curvature (instead of the intrinsic curvature). Such an extrinsic curvature embedding diagram, when used together with the usual kind of intrinsic curvature embedding diagram, carries the information of how a surface is {\\it embedded} in the higher dimensional curved space. Simple examples are given to illustrate the idea.

Lu, J L

2003-01-01

155

Tree Diagrams and Probability  

Science.gov (United States)

This lesson is designed to develop students' ability to create tree diagrams and figure probabilities of events based on those diagrams. This lesson provides links to discussions and activities related to tree diagrams as well as suggested ways to work them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

156

Analysis of Nike distribution facility's outbound process flow  

OpenAIRE

A simulation study was conducted to run different scenarios on the outbound process flow affected by the Soccer World Cup 2010 event. Along with Excel spreadsheets this simulation proved to be vital in the decision making of the build up for the World Cup. The results obtained showed that not all KPI’s where at their optimal level, thus changes where made in the number of resource at certain workstations. It also indicated that the system was resistant to change and modifications on proc...

Wagenaar, Werner

2009-01-01

157

Microfluidic-SANS: flow processing of complex fluids  

Science.gov (United States)

Understanding and engineering the flow-response of complex and non-Newtonian fluids at a molecular level is a key challenge for their practical utilisation. Here we demonstrate the coupling of microfluidics with small angle neutron scattering (SANS). Microdevices with high neutron transmission (up to 98%), low scattering background (), broad solvent compatibility and high pressure tolerance (~3-15 bar) are rapidly prototyped via frontal photo polymerisation. Scattering from single microchannels of widths down to 60 ?m, with beam footprint of 500 ?m diameter, was successfully obtained in the scattering vector range 0.01-0.3 Å-1, corresponding to real space dimensions of . We demonstrate our approach by investigating the molecular re-orientation and alignment underpinning the flow response of two model complex fluids, namely cetyl trimethylammonium chloride/pentanol/D2O and sodium lauryl sulfate/octanol/brine lamellar systems. Finally, we assess the applicability and outlook of microfluidic-SANS for high-throughput and flow processing studies, with emphasis of soft matter.

Lopez, Carlos G.; Watanabe, Takaichi; Martel, Anne; Porcar, Lionel; Cabral, João T.

2015-01-01

158

Microfluidic-SANS: flow processing of complex fluids.  

Science.gov (United States)

Understanding and engineering the flow-response of complex and non-Newtonian fluids at a molecular level is a key challenge for their practical utilisation. Here we demonstrate the coupling of microfluidics with small angle neutron scattering (SANS). Microdevices with high neutron transmission (up to 98%), low scattering background (), broad solvent compatibility and high pressure tolerance (?3-15 bar) are rapidly prototyped via frontal photo polymerisation. Scattering from single microchannels of widths down to 60??m, with beam footprint of 500??m diameter, was successfully obtained in the scattering vector range 0.01-0.3?Å(-1), corresponding to real space dimensions of . We demonstrate our approach by investigating the molecular re-orientation and alignment underpinning the flow response of two model complex fluids, namely cetyl trimethylammonium chloride/pentanol/D2O and sodium lauryl sulfate/octanol/brine lamellar systems. Finally, we assess the applicability and outlook of microfluidic-SANS for high-throughput and flow processing studies, with emphasis of soft matter. PMID:25578326

Lopez, Carlos G; Watanabe, Takaichi; Martel, Anne; Porcar, Lionel; Cabral, João T

2015-01-01

159

Analysis of the Flow Pipe Arrangement in RTM Process  

Directory of Open Access Journals (Sweden)

Full Text Available In RTM process, the condition which the flow of resin in the pipeline according with the Darcy's law is the movement of laminar fluid and the Reynolds number less than 1. This paper simulated the flow of the resin in the pipeline by changing the length and diameter of the passageway of pipeline with finite element analytical method. In the result, the relationship of the fluid speed on the exit in pipeline and Reynolds number, also the scope of flow rate of the resin in the pipes can be gained. The test result shows that: exit velocity had little to do with the length, but the ratio of pipeline diameter. When the diameter of entrance assume value of 6 mm,10mm,16mm and 20mm and the diameter of exit 6 mm, 10mm and 16 mm respectively, the maximum speed should be 694.442 mm per second, 416.667 mm per second and 260.414 mm per second accordingly.

Jinliang Liu

2009-02-01

160

Coded Ultrasound for Blood Flow Estimation Using Subband Processing  

DEFF Research Database (Denmark)

This paper investigates the use of coded excitation for blood flow estimation in medical ultrasound. Traditional autocorrelation estimators use narrow-band excitation signals to provide sufficient signal-to-noise-ratio (SNR) and velocity estimation performance. In this paper, broadband coded signals are used to increase SNR, followed by subband processing. The received broadband signal is filtered using a set of narrow-band filters. Estimating the velocity in each of the bands and averaging the results yields better performance compared with what would be possible when transmitting a narrow-band pulse directly. Also, the spatial resolution of the narrow-band pulse would be too poor for brightness-mode (B-mode) imaging, and additional transmissions would be required to update the B-mode image. For the described approach in the paper, there is no need for additional transmissions, because the excitation signal is broadband and has good spatial resolution after pulse compression. This means that time can be saved by using the same data for B-mode imaging and blood flow estimation. Two different coding schemes are used in this paper, Barker codes and Golay codes. The performance of the codes for velocity estimation is compared with a conventional approach transmitting a narrow-band pulse. The study was carried out using an experimental ultrasound scanner and a commercial linear array 7 MHz transducer. A circulating flow rig was scanned with a beam-to-flow angle of 60°. The flow in the rig was laminar and had a parabolic flow-profile with a peak velocity of 0.09 m/s. The mean relative standard deviation of the velocity estimate using the reference method with an 8-cycle excitation pulse at 7 MHz was 0.544% compared with the peak velocity in the rig. Two Barker codes were tested with a length of 5 and 13 bits, respectively. The corresponding mean relative standard deviations were 0.367% and 0.310%, respectively. For the Golay coded experiment, two 8-bit codes were used, and the mean relative standard deviation was 0.335%.

Gran, Fredrik; Udesen, Jesper

2008-01-01

161

Features, Events and Processes in UZ Flow and Transport  

International Nuclear Information System (INIS)

The purpose of this report is to evaluate and document the inclusion or exclusion of the unsaturated zone (UZ) features, events, and processes (FEPs) with respect to modeling that supports the total system performance assessment (TSPA) for license application (LA) for a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either Included or Excluded, is given for each FEP, along with the technical basis for the screening decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 173273]. The FEPs deal with UZ flow and radionuclide transport, including climate, surface water infiltration, percolation, drift seepage, and thermally coupled processes. This analysis summarizes the implementation of each FEP in TSPA-LA (that is, how the FEP is included) and also provides the technical basis for exclusion from TSPA-LA (that is, why the FEP is excluded). This report supports TSPA-LA

162

Features, Events, and Processes in UZ Flow and Transport  

International Nuclear Information System (INIS)

The purpose of this report is to evaluate and document the inclusion or exclusion of the unsaturated zone (UZ) features, events, and processes (FEPs) with respect to modeling that supports the total system performance assessment (TSPA) for license application (LA) for a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either ''Included'' or ''Excluded'', is given for each FEP, along with the technical basis for the screening decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 156605]. The FEPs deal with UZ flow and radionuclide transport, including climate, surface water infiltration, percolation, drift seepage, and thermally coupled processes. This analysis summarizes the implementation of each FEP in TSPA-LA (that is, how the FEP is included) and also provides the technical basis for exclusion from TSPA-LA (that is, why the FEP is excluded). This report supports TSPA-LA

163

Between Analogue and Digital Diagrams  

OpenAIRE

This essay is about the interstitial. About how the diagram, as a method of design, has lead fromthe analogue deconstruction of the eighties to the digital processes of the turn of the millennium.Specifically, the main topic of the text is the interpretation and the critique of folding (as a diagram)in the beginning of the nineties. It is necessary then to unfold its relationship with immediatelypreceding and following architectural trends, that is to say we have to look both backwards andfor...

Zoltan Bun

2012-01-01

164

The thermal process diagram and equipment of the secondary coolant circuit of a nuclear power station unit based on the BREST-OD-300 reactor installation for subcritical steam conditions  

Science.gov (United States)

The 300-MWe power unit based on an experimental-demonstration two-circuit 700-MWt reactor installation with lead coolant is briefly described. The thermal process diagram of the secondary coolant circuit for the subcritical steam conditions 17 MPa and 505°C at the outlet from steam generators is presented.

Nesterov, Yu. V.; Lisyanskii, A. S.; Makarova, E. I.; Bal'Va, L. Ya.; Prikhod'Ko, P. Yu.

2011-06-01

165

Hyporheic flow and transport processes: Mechanisms, models, and biogeochemical implications  

Science.gov (United States)

years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed.

Boano, F.; Harvey, J. W.; Marion, A.; Packman, A. I.; Revelli, R.; Ridolfi, L.; Wörman, A.

2014-12-01

166

Modelling of energy flows in potato crisp frying processes  

International Nuclear Information System (INIS)

Food frying is very energy intensive and in industrial potato crisp production lines frying is responsible for more than 90% of the total energy consumption of the process. This paper considers the energy flows in crisp frying using a First Law of Thermodynamics modelling approach which was verified against data from a potato crisp production line. The results indicate that for the frying process considered, most of the energy used is associated with the evaporation of water present in the potato and on the surface of potato slices. The remainder is from evaporation of frying oil and air of the ventilation system and heat losses from the fryer wall surfaces by convection and radiation. The frying oil is heated by an industrial gas furnace and the efficiency of this process was calculated to be 84%. The efficiency of the overall frying process which was found to be of the order of 70% can be improved by employing exhaust heat recovery and optimising other operating and control parameters such as exhaust gas recirculation.

167

Hyporheic flow and transport processes: mechanisms, models, and biogeochemical implications  

Science.gov (United States)

Fifty years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed."

Boano, Fulvio; Harvey, Judson W.; Marion, Andrea; Packman, Aaron I.; Revelli, Roberto; Ridolfi, Luca; Anders, Wörman

2014-01-01

168

Engineered Barrier System Degradation, Flow, and Transport Process Model Report  

International Nuclear Information System (INIS)

The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II)

169

Engineered Barrier System Degradation, Flow, and Transport Process Model Report  

Energy Technology Data Exchange (ETDEWEB)

The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).

E.L. Hardin

2000-07-17

170

Features, Events, and Processes in SZ Flow and Transport  

International Nuclear Information System (INIS)

This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either ''Included'' or ''Excluded'', is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), (f) (DIRS 156605). This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded)

171

Features, Events, and Processes in SZ Flow and Transport  

International Nuclear Information System (INIS)

This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.11(d), (e), (f) [DIRS 173273]. This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded)

172

Features, Events, and Processes in SZ Flow and Transport  

Energy Technology Data Exchange (ETDEWEB)

This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either ''Included'' or ''Excluded'', is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), (f) (DIRS 156605). This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded).

K. Economy

2004-11-16

173

Features, Events, and Processes in SZ Flow and Transport  

Energy Technology Data Exchange (ETDEWEB)

This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.11(d), (e), (f) [DIRS 173273]. This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded).

S. Kuzio

2005-08-20

174

Manufacturing process planning optimisation in reconfigurable multiple parts flow lines  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This paper explores the capabilities of genetic algorithms in handling optimization of the criticalissues mentioned above for the purpose of manufacturing process planning in reconfigurable manufacturingactivities. Two modified genetic algorithms are devised and employed to provide the best approximate processplanning solution. Modifications included adapting genetic operators to the problem specific knowledge andimplementing application specific heuristics to enhance the search efficiency.Design/methodology/approach: The genetic algorithm methodology implements a genetic algorithmthat is augmented by application specific heuristics in order to guide the search for an optimal solution.The case study is based on the manufacturing system. Raw materials enter the system through an input stageand exit the system through an output stage. The system is composed of sixteen (16 processing modulesthat are arranged in four processing stages.Findings: The results indicate that the two genetic algorithms are able to converge to optimal solutionsin reasonable time. A computational study shows that improved solutions can be obtained by implementinga genetic algorithm with an extended diversity control mechanism.Research limitations/implications: This paper has examined the issues of MPP optimization in a reconfigurablemanufacturing framework with the help of a reconfigurable multiparts manufacturing flow line.Originality/value: The results of the case illustration have demonstrated the practical use of diversity controlimplemented in the MGATO technique. In comparison to MGAWTO, the implemented MGATO improves thepopulation diversity through a customized threshold operator. It was clear that the MGATO can obtain bettersolution quality by foiling the tendency towards premature convergence.

N. Ismail

2008-12-01

175

Material flow simulation in a nuclear chemical process  

International Nuclear Information System (INIS)

At a nuclear fuel reprocessing plant the special nuclear materials (SNM) are received as constituents of spent fuel assemblies, are converted to liquid form, and undergo a series of chemical processes. Uncertainties in measurements of SNM at each stage of reprocessing limit the accuracy of simple material balance accounting as a safeguards method. To be effective, a formal safeguards program must take into account all sources of measurement error yet detect any diversion of SNM. An analytical method for assessing the accountability of selected constituent SNM is demonstrated. A combined discrete-continuous, time-dependent model using the GASP IV simulation language is developed to simulate mass flow, material accountability and measurement error at each stage of the reprocessing plant

176

Measuring information flow in networks of stochastic processes  

CERN Document Server

Social networks are considered in this paper as networks of interacting stochastic processes. We study the problem of inferring the circulation of information between network nodes. To take into account feedback between signals, as well as instantaneous interaction, we show that the adequate measures of information flow are the directed information and the causal conditional directed information. We relate the framework based on directed information theory to the theory of Granger causality in multivariate time series. An important result of the paper is the proof that linear implementation of Granger causality and directed information theory are equivalent in the Gaussian case. This is proved for the bivariate analysis as well as for the multivariate analysis, for which we extend some of Geweke's results. The relations between directed information and transfer entropy are provided. A simulation illustrates the main results obtained in the paper through the problem of inferring effective connectivity in a net...

Amblard, Pierre-Olivier

2009-01-01

177

Braided chord diagrams  

OpenAIRE

The notion of a braided chord diagram is introduced and studied. An equivalence relation is given which identifies all braidings of a fixed chord diagram. It is shown that finite-type invariants are stratified by braid index for knots which can be represented as closed 3-braids. Partial results are obtained about spanning sets for the algebra of chord diagrams of braid index 3.

Birman, Joan S.; Trapp, Rolland

1998-01-01

178

Eigenanalysis of a neural network for optic flow processing  

International Nuclear Information System (INIS)

Flies gain information about self-motion during free flight by processing images of the environment moving across their retina. The visual course control center in the brain of the blowfly contains, among others, a population of ten neurons, the so-called vertical system (VS) cells that are mainly sensitive to downward motion. VS cells are assumed to encode information about rotational optic flow induced by self-motion (Krapp and Hengstenberg 1996 Nature 384 463-6). Recent evidence supports a connectivity scheme between the VS cells where neurons with neighboring receptive fields are connected to each other by electrical synapses at the axonal terminals, whereas the boundary neurons in the network are reciprocally coupled via inhibitory synapses (Haag and Borst 2004 Nat. Neurosci. 7 628-34; Farrow et al 2005 J. Neurosci. 25 3985-93; Cuntz et al 2007 Proc. Natl Acad. Sci. USA). Here, we investigate the functional properties of the VS network and its connectivity scheme by reducing a biophysically realistic network to a simplified model, where each cell is represented by a dendritic and axonal compartment only. Eigenanalysis of this model reveals that the whole population of VS cells projects the synaptic input provided from local motion detectors on to its behaviorally relevant components. The two major eigenvectors consist of a horizontal and a slanted line representing the distribution of vertical motion components across the fly's azimuth. They are, thus, ideally su fly's azimuth. They are, thus, ideally suited for reliably encoding translational and rotational whole-field optic flow induced by respective flight maneuvers. The dimensionality reduction compensates for the contrast and texture dependence of the local motion detectors of the correlation-type, which becomes particularly pronounced when confronted with natural images and their highly inhomogeneous contrast distribution

179

Global quantum Hall phase diagram from visibility diagrams  

CERN Document Server

We propose a construction of a global phase diagram for the quantum Hall effect. This global phase diagram is based on our previous constructions of visibility diagrams in the context of the Quantum Hall Effect. The topology of the phase diagram we obtain is in good agreement with experimental observations (when the spin effect can be neglected). This phase diagram does not show floating.

Chandelier, F; Masson, T; Wallet, J C; Chandelier, Frederique; Georgelin, Yvon; Masson, Thierry; Wallet, Jean-Christophe

2002-01-01

180

Hertzsprung-Russell Diagram  

Science.gov (United States)

This activity teaches students about the Hertzsprung-Russell diagram. The students will first describe differences between near and bright stars. Then they will discern a relationship between temperature and brightness. Finally they will correlate the evolution of stars to plotting the H-R diagram.

Slater, Tim P.

2004-07-16

181

Fractional Flow Theory Applicable to Non-Newtonian Behavior in EOR Processes:  

OpenAIRE

The method of characteristics, or fractional-flow theory, is extremely useful in understanding complex Enhanced Oil Recovery (EOR) processes and in calibrating simulators. One limitation has been its restriction to Newtonian rheology except in rectilinear flow. Its inability to deal with non-Newtonian rheology in polymer and foam EOR has been a serious limitation. We extend fractional flow methods for two-phase flow to non-Newtonian fluids in one-dimensional cylindrical flow, where rheology c...

Rossen, W. R.; Venkatraman, A.; Johns, R. T.; Kibodeaux, K. R.; Lai, H.; Moradi Tehrani, N.

2011-01-01

182

Logical reasoning with diagrams  

CERN Document Server

PART A: Theoretical Issues. 1. Visual Information and Valid Reasoning, Jon Barwise and John Etchemendy. 2. Operational Constraints in Diagrammatic Reasoning, Atsushi Shimojima. 3. Diagrams and the Concept of Logical System, Jon Barwise and Eric Hammer. PART B: Case Studies. 4. Situation-Theoretic Account of Valid Reasoning with Venn Diagrams, Sun-Joo Shin. 5. Towards a Model Theory of Venn Diagrams, eric Hammer and Norman Danner. 6. Peircean Graphs for Propositional Logic, Eric Hammer. 7. A Diagrammatic Subsystem of Hilbert''s Geometry, Isabel Luengo. PART C: Heterogenous Systems. 8. Heterogenous Logic, Jon Barwise and John Etchemendy. 9. Toward the Rigorous Use of Diagrams in Reasoning about Hardware, Steven D. Johnson, Jon Barwise, and Gerard Allwein. 10. Exploiting the Potential of Diagrams in Guiding Hardware Reasoning, Kathi D. Fisler

Allwein, Gerard

1996-01-01

183

Fourier processing of liquid chromatograms using flow radioactive detection.  

Science.gov (United States)

Flow radioactivity counters coupled to liquid chromatography devices cause a systematic bias to the separation by broadening peaks within the radiochromatogram. Such signal smearing may be evaluated on standardization runs with a single peak, using the ratio between Fourier transforms of whole chromatographic data for the measured radioactivity time series (radioactivity channel) and for the concentration time series (optical density channel). This ratio constitutes a kernel suitable to perform the deconvolution of any radiochromatogram performed under similar conditions. Through deconvolution, the signal smearing is removed, reverting to peaks with the same geometry as in the concentration chromatogram: same retention time, peak width, and shape. The deconvolution method in processing radiochromatograms allows an easier interpretation and gives more reliable radioactivity quantification (improved linearity of the measured response). Fourier transformation of the radiochromatogram also allows the removal of transitory events (noise) through the correlation procedure. This method may provide substantial gain in sensitivity, depending upon the residence time of the sample in the counting cell. PMID:7710093

Bonnot, G; Febvay, G

1995-01-01

184

Neuro-flow Dynamics and the Learning Processes  

CERN Document Server

A new description of the neural activity is introduced by the neuro-flow dynamics and the extended Hebb rule. The remarkable characteristics of the neuro-flow dynamics, such as the primacy and the recency effect during awakeness or sleep, are pointed out.

Tatsuno, M

1997-01-01

185

Modal Object Diagrams  

OpenAIRE

While object diagrams (ODs) are widely used as a means to document object-oriented systems, they are expressively weak, as they are limited to describe specific possible snapshots of the system at hand. In this paper we introduce modal object diagrams (MODs), which extend the classical OD language with positive/negative and example/invariant modalities. The extended language allows the designer to specify not only positive example models but also negative examples, ones that...

Maoz, Shahar; Ringert, Jan Oliver; Rumpe, Bernhard

2014-01-01

186

INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 26. TITANIUM INDUSTRY  

Science.gov (United States)

The titanium industry produces two principal products, titanium metal and titanium dioxide. For purposes of analyses, therefore, the industry is considered in two segments: titanium metal production and titanium dioxide production. Two industrial process flow diagrams and eleven ...

187

Large eddy simulations of turbulent flows on graphics processing units: Application to film-cooling flows  

Science.gov (United States)

Computational Fluid Dynamics (CFD) simulations can be very computationally expensive, especially for Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS) of turbulent ows. In LES the large, energy containing eddies are resolved by the computational mesh, but the smaller (sub-grid) scales are modeled. In DNS, all scales of turbulence are resolved, including the smallest dissipative (Kolmogorov) scales. Clusters of CPUs have been the standard approach for such simulations, but an emerging approach is the use of Graphics Processing Units (GPUs), which deliver impressive computing performance compared to CPUs. Recently there has been great interest in the scientific computing community to use GPUs for general-purpose computation (such as the numerical solution of PDEs) rather than graphics rendering. To explore the use of GPUs for CFD simulations, an incompressible Navier-Stokes solver was developed for a GPU. This solver is capable of simulating unsteady laminar flows or performing a LES or DNS of turbulent ows. The Navier-Stokes equations are solved via a fractional-step method and are spatially discretized using the finite volume method on a Cartesian mesh. An immersed boundary method based on a ghost cell treatment was developed to handle flow past complex geometries. The implementation of these numerical methods had to suit the architecture of the GPU, which is designed for massive multithreading. The details of this implementation will be described, along with strategies for performance optimization. Validation of the GPU-based solver was performed for fundamental bench-mark problems, and a performance assessment indicated that the solver was over an order-of-magnitude faster compared to a CPU. The GPU-based Navier-Stokes solver was used to study film-cooling flows via Large Eddy Simulation. In modern gas turbine engines, the film-cooling method is used to protect turbine blades from hot combustion gases. Therefore, understanding the physics of this problem as well as techniques to improve it is important. Fundamentally, a film-cooling configuration is an inclined cooling jet in a hot cross-flow. A known problem in the film-cooling method is jet lift-off, where the jet of coolant moves away from the surface to be cooled due to mutual vortex induction by the counter-rotating vortex pair embedded in the jet, resulting in decreased cooling at the surface. To counteract this, a micro-ramp vortex generator was added downstream of the film-cooling jet, which generated near-wall counter-rotating vortices of opposite sense to the vortex pair in the jet. It was found that the micro-ramp vortices created a downwash effect toward the wall, which helped entrain coolant from the jet and transport it to the wall, resulting in better cooling. Results are reported using two film-cooling configurations, where the primary difference is the way the jet exit boundary conditions are prescribed. In the first configuration, the jet is prescribed using a precursor simulation and in the second the jet is modeled using a plenum/pipe configuration. The latter configuration was designed based on previous wind tunnel experiments at NASA Glenn Research Center, and the present results were meant to supplement those experiments.

Shinn, Aaron F.

188

Evolution of Plastic Strain During a Flow Forming Process  

CERN Document Server

The distribution of equivalent plastic strain through the thickness of several AISI 1020 steel plates formed under different conditions over a smooth cylindrical mandrel using a single-roller forward flow forming operation was studied by measuring the local micro-indentation hardness of the deformed material. The equivalent plastic strain was higher at the inner and outer surfaces and lowest at the center of the workpiece. Empirical expressions are presented which describe the contribution of the roller and mandrel to the total local equivalent plastic strain within the flow formed part. The dependence of these expressions upon the thickness reduction during flow forming is discussed.

Roy, M J; Wood, J T; 10.1016/j.jmatprotec.2008.03.030

2011-01-01

189

Determination of forming limit stress diagrams for the characterization of material for sheet metal forming  

Energy Technology Data Exchange (ETDEWEB)

Forming limit diagrams (FLD) are usually used to predict the possible failure of the material in a sheet metal forming process. The FLD shows the maximum strain to failure as a function of the strain state. Another way of describing the deformation limit of a material is a forming limit stress diagram (FLSD), which shows the equivalent stress to failure as a function of the principal stresses. The FLSD is independent of the deformation history and the deformation path of the material, which is in contrast to the commonly used forming limit diagram (FLD). FLSDs for five different deep drawing steel grades have been calculated from data of previously determined FLDs, flow curves, and anisotropy coefficients. (orig.)

Kaluza, W.; Kim, I.; Bleck, W. [RWTH Aachen Univ. of Technology (Germany). Dept. of Ferrous Metallurgy

2002-04-01

190

Stochastic Modelling of Shiroro River Stream flow Process  

Directory of Open Access Journals (Sweden)

Full Text Available Economists, social scientists and engineers provide insights into the drivers of anthropogenic climate change and the options for adaptation and mitigation, and yet other scientists, including geographers and biologists, study the impacts of climate change. This project concentrates mainly on the discharge from the Shiroro River. A stochastic approach is presented for modeling a time series by an Autoregressive Moving Average model (ARMA. The development and use of a stochastic stream flow model involves some basic steps such as obtain stream flow record and other information, Selecting models that best describes the marginal probability distribution of flows. The flow discharge of about 22 years (1990-2011 was gotten from the Meteorological Station at Shiroro and analyzed with three different models namely; Autoregressive (AR model, Autoregressive Moving Average (ARMA model and Autoregressive Integrated Moving Average (ARIMA model. The initial model identification is done by using the autocorrelation function (ACF and partial autocorrelation function (PACF. Based on the model analysis and evaluations, proper predictions for the effective usage of the flow from the river for farming activities and generation of power for both industrial and domestic us were made. It also highlights some recommendations to be made to utilize the possible potentials of the river effectively

Musa, J. J

2013-01-01

191

Probing the QCD phase diagram with measurements of phi-meson production and elliptic flow in heavy-ion collisions at STAR  

Science.gov (United States)

We present measurements of phi-meson production and elliptic flow (v2) at mid-rapidity in Au + Au collisions at = 7.7 - 200 GeV. Energy dependence of nuclear modification factor (RCP) of phi meson is presented. The phi-meson RCP has a value >= 1.0 for = 19.6 GeV, which can be considered as an evidence of partonic collectivity. We observe that phi-meson v2 falls off the trend from the other hadrons at highest measured pT values by 1.8? and 2.3? at = 7.7 and 11.5 GeV, respectively.

Nasim, Md; Star Collaboration

2014-05-01

192

Energy-flow-reversing N processes in elastically anisotropic crystals  

Science.gov (United States)

Energy- and momentum-conserving phonon-phonon interactions can give rise to a reversal in the net energy flow per unit area, U, in crystals having sufficient elastic anisotropy. This results because the direction of phonon momentum is, in general, not parallel to the energy-flow vector in elastically anisotropic crystals. Conditions for energy-flow reversal (EFR) about a or reference axis have been calculated for cubic crystals when the wave vectors of the three interacting phonons are constrained to a \\{100\\} or [110\\} symmetry plane. Six interactions qualify for EFR under these conditions when the elastic anisotropy factor A>1 two qualify when AEFR in one or more of these interactions. A proposed room-temperature experiment is described to demonstrate EFR in tetragonal paratellurite.

McCurdy, A. K.

1988-11-01

193

Geometries from Young diagrams  

International Nuclear Information System (INIS)

Type IIB string theory on spacetimes that are asymptotically AdS5 x S5 can be defined using four dimensional N = 4 super Yang-Mills theory. Six of the dimensions of the string theory are holographically reconstructed in the Yang-Mills theory. In this article we study how these dimensions and local physics in these dimensions emerge. We reorganize the dynamics of the 1/2 BPS sector of the field theory by rewriting it in terms of Schur polynomials. The Young diagram labeling of these polynomials can be viewed as a book keeping device which summarizes how the operator is constructed. We show that aspects of the geometry of the extra holographic dimensions are captured very naturally by the Young diagram. Gravitons which are localized at a specific position in the bulk correspond to boxes added at a specific location on the Young diagram.

194

Microreactors with integrated UV/Vis spectroscopic detection for online process analysis under segmented flow.  

Science.gov (United States)

Combining reaction and detection in multiphase microfluidic flow is becoming increasingly important for accelerating process development in microreactors. We report the coupling of UV/Vis spectroscopy with microreactors for online process analysis under segmented flow conditions. Two integration schemes are presented: one uses a cross-type flow-through cell subsequent to a capillary microreactor for detection in the transmission mode; the other uses embedded waveguides on a microfluidic chip for detection in the evanescent wave field. Model experiments reveal the capabilities of the integrated systems in real-time concentration measurements and segmented flow characterization. The application of such integration for process analysis during gold nanoparticle synthesis is demonstrated, showing its great potential in process monitoring in microreactors operated under segmented flow. PMID:24178763

Yue, Jun; Falke, Floris H; Schouten, Jaap C; Nijhuis, T Alexander

2013-12-21

195

Influence of surface processes on gas flow in nanoscale capillaries  

International Nuclear Information System (INIS)

Theoretical study of free molecular gas flow in nanoscale capillary taking into account joint effect of different schemes of molecule scattering by the capillary wall and surface diffusion of adsorbed molecules is conducted. The problem of radiation-induced drift of molecules in capillaries is discussed. Influence of adsorbable foreign gases on phase transitions in nanoscale capillaries is considered. (authors)

196

Modeling field scale unsaturated flow and transport processes  

International Nuclear Information System (INIS)

The scales of concern in subsurface transport of contaminants from low-level radioactive waste disposal facilities are in the range of 1 to 1,000 m. Natural geologic materials generally show very substantial spatial variability in hydraulic properties over this range of scales. Such heterogeneity can significantly influence the migration of contaminants. It is also envisioned that complex earth structures will be constructed to isolate the waste and minimize infiltration of water into the facility. The flow of water and gases through such facilities must also be a concern. A stochastic theory describing unsaturated flow and contamination transport in naturally heterogeneous soils has been enhanced by adopting a more realistic characterization of soil variability. The enhanced theory is used to predict field-scale effective properties and variances of tension and moisture content. Applications illustrate the important effects of small-scale heterogeneity on large-scale anisotropy and hysteresis and demonstrate the feasibility of simulating two-dimensional flow systems at time and space scales of interest in radioactive waste disposal investigations. Numerical algorithms for predicting field scale unsaturated flow and contaminant transport have been improved by requiring them to respect fundamental physical principles such as mass conservation. These algorithms are able to provide realistic simulations of systems with very dry initial conditions and high degrees of heterogeneity. Numerical simulation of the movement of water and air in unsaturated soils has demonstrated the importance of air pathways for contaminant transport. The stochastic flow and transport theory has been used to develop a systematic approach to performance assessment and site characterization. Hypothesis-testing techniques have been used to determine whether model predictions are consistent with observed data

197

Novel process windows for enabling, accelerating, and uplifting flow chemistry.  

Science.gov (United States)

Novel Process Windows make use of process conditions that are far from conventional practices. This involves the use of high temperatures, high pressures, high concentrations (solvent-free), new chemical transformations, explosive conditions, and process simplification and integration to boost synthetic chemistry on both the laboratory and production scale. Such harsh reaction conditions can be safely reached in microstructured reactors due to their excellent transport intensification properties. This Review discusses the different routes towards Novel Process Windows and provides several examples for each route grouped into different classes of chemical and process-design intensification. PMID:23606410

Hessel, Volker; Kralisch, Dana; Kockmann, Norbert; Noël, Timothy; Wang, Qi

2013-05-01

198

Simulations of ductile flow in brittle material processing  

Energy Technology Data Exchange (ETDEWEB)

Research is continuing on the effects of thermal properties of the cutting tool and workpiece on the overall temperature distribution. Using an Eulerian finite element model, diamond and steel tools cutting aluminum have been simulated at various, speeds, and depths of cut. The relative magnitude of the thermal conductivity of the tool and the workpiece is believed to be a primary factor in the resulting temperature distribution in the workpiece. This effect is demonstrated in the change of maximum surface temperatures for diamond on aluminum vs. steel on aluminum. As a preliminary step toward the study of ductile flow in brittle materials, the relative thermal conductivities of diamond on polycarbonate is simulated. In this case, the maximum temperature shifts from the rake face of the tool to the surface of the machined workpiece, thus promoting ductile flow in the workpiece surface.

Luh, M.H.; Strenkowski, J.S.

1988-12-01

199

Stochastic Modelling of Shiroro River Stream flow Process  

OpenAIRE

Economists, social scientists and engineers provide insights into the drivers of anthropogenic climate change and the options for adaptation and mitigation, and yet other scientists, including geographers and biologists, study the impacts of climate change. This project concentrates mainly on the discharge from the Shiroro River. A stochastic approach is presented for modeling a time series by an Autoregressive Moving Average model (ARMA). The development and use of a stochastic stream flow m...

Musa, J. J.

2013-01-01

200

Gaussian process emulators for uncertainty analysis in groundwater flow  

OpenAIRE

In the field of underground radioactive waste disposal, complex computer models are used to describe the flow of groundwater through rocks. An important property in this context is transmissivity, the ability of the groundwater to pass through rocks, and the transmissivity field can be represented by a stochastic model. The stochastic model is included in complex computer models which determine the travel time for radionuclides released at one point to reach another. As well as the uncerta...

Stone, Nicola

2011-01-01

201

Microfluidic-SANS: flow processing of complex fluids  

OpenAIRE

Understanding and engineering the flow-response of complex and non-Newtonian fluids at a molecular level is a key challenge for their practical utilisation. Here we demonstrate the coupling of microfluidics with small angle neutron scattering (SANS). Microdevices with high neutron transmission (up to 98%), low scattering background (), broad solvent compatibility and high pressure tolerance (?3–15 bar) are rapidly prototyped via frontal photo polymerisation. Scattering from single microch...

Lopez, Carlos G.; Watanabe, Takaichi; Martel, Anne; Porcar, Lionel; Cabral, Joa?o T.

2015-01-01

202

Integrated flow and transport processes in subsurface -drained agricultural fields  

OpenAIRE

Describing water and solute movement in subsurface-drained agricultural fields is challenging due, in part, to an array of macropores that network the soil matrix. Using the hypothesis that subsurface-drained fields integrate the effects of spatial heterogeneity, effective parameters was calibrated for a flow and transport model (HYDRUS-2D) using drain outflow data. Though some success in simulating water flux was achieved using a dual-porosity representation, the effective parameter simulati...

Haws, Nathan W.

2003-01-01

203

Flow-Injection Responses of Diffusion Processes and Chemical Reactions  

DEFF Research Database (Denmark)

The technique of Flow-injection Analysis (FIA), now aged 25 years, offers unique analytical methods that are fast, reliable and consuming an absolute minimum of chemicals. These advantages together with its inherent feasibility for automation warrant the future applications of FIA as an attractive tool of automated analytical chemistry. The need for an even lower consumption of chemicals and for computer analysis has motivated a study of the FIA peak itself, that is, a theoretical model was developed, that provides detailed knowledge of the FIA profile. It was shown that the flow in a FIA manifold may be characterised by a diffusion coefficient that depends on flow rate, denoted as the kinematic diffusion coefficient. The description was applied to systems involving species of chromium, both in the case of simple diffusion and in the case of chemical reactions. It is suggested that it may be used in the resolution of FIA profiles to obtain information about the content of interference’s, in the study of chemical reaction kinetics and to measure absolute concentrations within the FIA-detector cell.

Andersen, Jens Enevold Thaulov

2000-01-01

204

Venn Diagrams and Logic  

Science.gov (United States)

This math lesson from Illuminations uses Venn diagrams to illustrate direct, indirect and transitive reasoning. Students will learn the definitions of direct, indirect and transitive reasoning and give examples of each. Several student activity sheets are included. The material is intended for grades 9-12 and should require 2 and a half class periods to complete.

2011-01-04

205

Reading Diagrams. Pipefitter.  

Science.gov (United States)

Developed by the ABCs of Construction National Workplace Literacy Project, these curriculum materials for the occupational area of pipefitting contain a lesson that deals with reading diagrams. The lesson consists of an objective, instruction, and 10 exercises. Three types of problems are provided in each exercise: "try it,""apply it," and "go…

Greater Baton Rouge Chamber of Commerce, LA.

206

Octopaminergic Modulation of Temporal Frequency Coding in an Identified Optic Flow-Processing Interneuron  

OpenAIRE

Flying generates predictably different patterns of optic flow compared with other locomotor states. A sensorimotor system tuned to rapid responses and a high bandwidth of optic flow would help the animal to avoid wasting energy through imprecise motor action. However, neural processing that covers a higher input bandwidth itself comes at higher energetic costs which would be a poor investment when the animal was not flying. How does the blowfly adjust the dynamic range of its optic flow-proce...

KitD.Longden

2010-01-01

207

A validation process for multi-phase reacting flow CFD code  

Energy Technology Data Exchange (ETDEWEB)

Computational fluid dynamic (CFD) code calculates flow properties for the analysis of a flow system. Flow properties are computed based on conservation principles and various phenomenological models. The accuracy of the computed flow properties highly depends on the validity of the models and the degree of numerical convergence. Validation of a CFD code is essential for application of an engineering system. Multiphase reacting flows are common in industrial applications and few CFD code are available. A CFD code was developed for the simulation of multiphase reacting flows. A validation process was also developed for such a CFD code. The validation was performed for several cases. Examples of industrial devices which are multiphase reacting flow systems include catalytic cracking reactors, glass melting furnaces, coal-fired combustors, and diesel engines.

Chang, S. L.; Zhou, C. Q.; Petrick, M.

2000-05-09

208

Special Issue: Design and Engineering of Microreactor and Smart-Scaled Flow Processes  

Directory of Open Access Journals (Sweden)

Full Text Available Reaction-oriented research in flow chemistry and microreactor has been extensively focused upon in special journal issues and books. On a process level, this resembled the “drop-in” (retrofit concept with the microreactor replacing a conventional (batch reactor. Meanwhile, with the introduction of the mobile, compact, modular container technology, the focus is more on the process side, including also providing an end-to-end vision of intensified process design. Exactly this is the focus of the current special issue “Design and Engineering of Microreactor and Smart-Scaled Flow Processes” of the journal “Processes”. This special issue comprises three review papers, five research articles and two communications. [...

Volker Hessel

2014-12-01

209

A theoretical study of resin flows for thermosetting materials during prepreg processing  

Science.gov (United States)

A flow model which describes the process of resin consolidation during prepreg lamination was developed. The salient features of model predictions were explored. It is assumed that resin flows in all directions originate from squeezing action between two approaching adjacent fiber/fabric layers. In the horizontal direction, a squeezing flow between two nonporous parallel plates is analyzed, while in the vertical direction a poiseuille type pressure flow through porous media is assumed. Proper force and mass balance was established for the whole system which is composed of these two types of flow. A flow parameter, CF, shows to be a measure of processibility for the curing resin. For a given external load-F the responses of resin flow during prepreg lamination, as measured by CF, are categorized into three regions: (1) the low CF region where resin flows are inhibited by the high chemoviscosity during initial curing stages; (2) the median CF region where resin flows are properly controllable; and (3) the high CF region where resin flows are ceased due to fiber/fabric compression effects. Resin losses in both directions are calculated. Potential uses of this model and quality control of incoming prepreg material are discussed.

Hou, T. H.

1984-01-01

210

Distribution flow: A general process in the top layer of water repellent soils  

Energy Technology Data Exchange (ETDEWEB)

Water and solute input rates on the soil surface may vary considerably from place to place. Distribution flow, i.e., the process of water and solute flow in a lateral direction over and through the very first millimeter or centimeter of the soil profile, is an extremely important process in distributing the rainfall toward places where vertical transport occurs. This study was carried out to quantify the process the distribution flow and its underlying process mechanism. A KBr tracer was applied on two water repellent sandy soils to follow the actual flow paths of water and solutes in the upper part of the profile. On both experimental fields, distribution flow actually displaced the applied bromide laterally through a very thin layer on the top of the soil profile, referred to as the {open_quotes}distribution layer.{close_quotes} Distribution flow was directed to locations within the 0- to 2.5- cm layer, where the soil was the least water repellent. On these relatively wet areas, the highest concentrations of bromide could be found. There was an acceleration in the vertical transport of water and bromide on these sites. Effects of distribution flow on the local concentration of water and solutes can be expected to be even more pronounced in uneven terrains, where lateral displacements may increase from the millimeter-centimeter scale to tens of meters. Implications for modeling field-scale water and solute flow are outlined. 71 refs., 9 figs., 2 tabs.

Ritsema, C.J.; Dekker, L.W. [DLO Winand Staring Centre for Integrated Land, Wageningen (Netherlands)

1995-05-01

211

Sensitivity analysis of reacting two-phase flow in nuclear heat-based gasification process  

Directory of Open Access Journals (Sweden)

Full Text Available Current work investigates influence of operating parameters on chemical reactions occuring within two-phase reacting flow. This particular flow analysed, corresponds to processes in coal gasifier unit supplied in heat by a high temperature gas cooled nuclear reactor (HTGR.Due to the fact that gasification is a complex process, in which multiphase mixture undergoes chemical reactions, it crucial to answer questions about sensitivity to parameters changes. Performed analysis was dedicated to answer question about the optimal flow parameters. Controll of flow patern, namely the swirl of coal-oxygen mixture traversing the gasifier domain, allowed creating efficiency curve, relating gas composition with non-axial component of the velocity vector.Using numerical model of the process, numbers of simulations were run in order to determine operation point yielding the highest efficiency, defined as a ratio of lower heating values of a syngas product of gasification process and coal feed into the unit.

Jakub Marcin Kupecki

2011-01-01

212

Views on the calculation of flow and dispersion processes in fractured rock  

International Nuclear Information System (INIS)

In the report some basic aspects on model types, physical processes, determination of parameters are discussed in relation to a description of flow and dispersion processes in fractured rocks. As far as model types concern it is shown that Darcy's law and the dispersion equation are not especially applicable. These equations can only describe an average situation of flow and spreading while in reality very large deviations could exist between an average situation and the flow and concentration distribution for a certain fracture geometry. The reason for this is primarily the relation between the length scales for the repository and the near field and the fracture system respectively and the poor connectivity between fractures or expressed in another way - the geosphere can not be treated as a continuous medium. The statistical properties of the fractures and the fracture geometry cause large uncertainties in at least two respects: * boundary conditions as to groundwater flow at the repository and thus the mass flow of radioactive material * distribution of flows and concentrations in planes in the geosphere on different distances from the repository. A realistic evaluation of transport and spreading of radioactive material by the groundwater in the geosphere thus requires that the possible variation or uncertainty of the water conducting characteristics of the fracture system is considered. A possible approach is then to describe flow in the geosphere on the basic of the flow in single fractures which are hydraulically connected to each other so that a flow in a fracture system is obtained. The discussion on physical processes which might influence the flow description in single fractures is concentrated to three aspects - factors driving the flow besides the ordinary hydraulic gradient, the viscous properties of water in a very small space (such as a fracture), the influence on the flow of heat release from the repository. (42 figs., 28 refs.)

213

Process and apparatus for analyzing gas flows inside hollow bodies  

International Nuclear Information System (INIS)

This invention concerns a real time technique for analyzing a gas flow moving through a hollow body such as a turbomachine, for obtaining three-dimensional information on the path taken by the gas when it passes through the motor. The difficulties to be overcome are constituted by the rate at which the gases move in the motor, the spreading of the gas flow in the body and the fact that the tracer employed in this analysis contaminates the exhaust gases, and possibly some of the motor, thereby leading to possible pollution hazards. This invention overcomes these troubles by using isotopes specially chosen for their short half life and the high radiation energy they generate, and by ensuring that the irradiation of the tracer substance occurs so as to produce an activity in the isotopes that is as great as possible and at the same time so as to enable the tracer to be injected in the motor as from the irradiation chamber for a very short period. The isotopes can be produced by bombardments of neutrons or by charged particles on to appropriate targets. A cyclotron is preferred as a source of charged particles

214

Heat transfer processes in the upper crust : influence of structure, fluid flow, and palaeoclimate  

OpenAIRE

Numerical models constrained by geological and geophysical data form the basis of understanding the thermal regime of the Earth's crust. This dissertation focuses on modelling heat transport in the upper crust, studying the relative contributions of different processes to the specific heat flow distribution. Its vertical variation is a well known fact, caused by different processes such as changes in surface temperature, fluid flow, and heterogeneity. In particular, the first one can provide ...

Mottaghy, Darius Christopher

2007-01-01

215

Sensitivity analysis of reacting two-phase flow in nuclear heat-based gasification process  

OpenAIRE

Current work investigates influence of operating parameters on chemical reactions occuring within two-phase reacting flow. This particular flow analysed, corresponds to processes in coal gasifier unit supplied in heat by a high temperature gas cooled nuclear reactor (HTGR).Due to the fact that gasification is a complex process, in which multiphase mixture undergoes chemical reactions, it crucial to answer questions about sensitivity to parameters changes. Performed analysis was dedicated to ...

Jakub Marcin Kupecki; Henryk Anglart; Krzysztof Badyda

2011-01-01

216

PROBLEMS AND TERMS OF THE IMPLEMENTATION OF OPTIMAL FLOW PROCESSES MANAGEMENT  

OpenAIRE

The relevance of the logistics concept concerning the solution of flow processes optimal control problems of industrial enterprises is discussed in the article. Modern tools of logistics make it possible to resolve the existing contradictions in Ukrainian economy by unifying business-structures into a single efficient system.While dealing with enterprise optimal management as a total combination of flow processes, logistics plays the main role as a regulator between an enterprise and resource...

Dzobko, I.; Zinkovsky, M.

2012-01-01

217

Generalized performance diagrams for steam turbine systems  

International Nuclear Information System (INIS)

Two generalized diagrams have been prepared for the steam turbine performance estimate. The diagrams can predict the turbine net heat rate for various turbine exhaust pressures and loadings. The turbine systems covered in these diagrams have the steam conditions either supercritical or subcritical, and the power output in the range of 400,000 kW to 800,000 kW. The turbine has 4 or 6 exhaust flows and the last stage blade length 23, 26, 30 or 33.5 inches. The basic approach is to normalize the turbine heat rates and express them in terms of turbine heat rates and express them in terms of turbine output per unit area of exhaust flow. The turbine exhaust pressure is treated as a parameter. Approximately 30 steam turbine system have been simulated by computer and the performance data were utilized in the construction of the generalized diagrams. The values predicted by this approach are in good agreement with the actual data

218

Comparison of Inflation Processes at the 1859 Mauna Loa Flow, HI, and the McCartys Flow Field, NM  

Science.gov (United States)

Basaltic lavas typically form channels or tubes during flow emplacement. However, the importance of sheet flow in the development of basalt ic terrains received recognition over the last 15 years. George Walke r?s research on the 1859 Mauna Loa Flow was published posthumously in 2009. In this paper he discusses the concept of endogenous growth, or inflation, for the distal portion of this otherwise channeldominated lava flow. We used this work as a guide when visiting the 1859 flow to help us better interpret the inflation history of the McCartys flow field in NM. Both well preserved flows display similar clues about the process of inflation. The McCartys lava flow field is among the you ngest (approx.3000 yrs) basaltic lava flows in the continental United States. It was emplaced over slopes of <1 degree, which is similar to the location within the 1859 flow where inflation occurred. Although older than the 1859 flow, the McCartys is located in an arid environ ment and is among the most pristine examples of sheet flow morphologies. At the meter scale the flow surface typically forms smooth, undula ting swales that create a polygonal terrain. The literature for simil ar features includes multiple explanatory hypotheses, original breakouts from adjacent lobes, or inflation related upwarping of crust or sa gging along fractures that enable gas release. It is not clear which of these processes is responsible for polygonal terrains, and it is po ssible that one explanation is not the sole cause of this morphology between all inflated flows. Often, these smooth surfaces within an inflated sheet display lineated surfaces and occasional squeeze-ups alon g swale contacts. We interpret the lineations to preserve original fl ow direction and have begun mapping these orientations to better interpret the emplacement history. At the scale of 10s to 100s of meters t he flow comprises multiple topographic plateaus and depressions. Some depressions display level floors with surfaces as described above, while some are bowl shaped with floors covered in broken lava slabs. Th e boundaries between plateaus and depressions are also typically smoo th, grooved surfaces that have been tilted to angles sometimes approaching vertical. The upper margin of these tilted surfaces displays lar ge cracks, sometimes containing squeeze-ups. The bottom boundary with smooth floored depressions typically shows embayment by younger lavas. It appears that this style of terrain represents the emplacement of an extensive sheet that experiences inflation episodes within prefer red regions where lateral spreading of the sheet is inhibited, thereby forming plateaus. Depressions are often the result of non-inflation and can be clearly identified by lateral squeeze-outs along the pit walls that form when the rising crust exposes the still liquid core of the sheet. Our current efforts are focused on.

Bleacher, Jacob E.; Garry, W. Brent; Zimbelman, James R.; Crumpler, Larry S.

2012-01-01

219

Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes  

Energy Technology Data Exchange (ETDEWEB)

In this report, the thrust areas include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

Yortsos, Yanis C.

2002-10-08

220

On the flow processes in sharply inclined and stalled airfoils in parallel movement and rotation  

Science.gov (United States)

The purpose of this study is to obtain a deeper insight into the complicated flow processes on airfoils in the region of the buoyancy maxima. To this end calculated and experimental investigations are carried out on a straight stationary, a twisted stationary and a straight rotating rectangular wing. According to the available results the method gives results which can be applied sufficiently for flow applied firmly on all sides for all rotation values. The reliability of the method may be questioned for a flow undergoing transition from the attached to the separated state or for totally separated flow and higher rotation values.

Kohler, M.

1984-01-01

221

Equivalent Temperature-Enthalpy Diagram for the Study of Ejector Refrigeration Systems  

Directory of Open Access Journals (Sweden)

Full Text Available The Carnot factor versus enthalpy variation (heat diagram has been used extensively for the second law analysis of heat transfer processes. With enthalpy variation (heat as the abscissa and the Carnot factor as the ordinate the area between the curves representing the heat exchanging media on this diagram illustrates the exergy losses due to the transfer. It is also possible to draw the paths of working fluids in steady-state, steady-flow thermodynamic cycles on this diagram using the definition of “the equivalent temperature” as the ratio between the variations of enthalpy and entropy in an analyzed process. Despite the usefulness of this approach two important shortcomings should be emphasized. First, the approach is not applicable for the processes of expansion and compression particularly for the isenthalpic processes taking place in expansion valves. Second, from the point of view of rigorous thermodynamics, the proposed ratio gives the temperature dimension for the isobaric processes only. The present paper proposes to overcome these shortcomings by replacing the actual processes of expansion and compression by combinations of two thermodynamic paths: isentropic and isobaric. As a result the actual (not ideal refrigeration and power cycles can be presented on equivalent temperature versus enthalpy variation diagrams. All the exergy losses, taking place in different equipments like pumps, turbines, compressors, expansion valves, condensers and evaporators are then clearly visualized. Moreover the exergies consumed and produced in each component of these cycles are also presented. The latter give the opportunity to also analyze the exergy efficiencies of the components. The proposed diagram is finally applied for the second law analysis of an ejector based refrigeration system.

Mohammed Khennich

2014-05-01

222

29 CFR 1926.64 - Process safety management of highly hazardous chemicals.  

Science.gov (United States)

...control loops are usually shown along with key utilities on process flow diagrams...Classification Guide,” 6th Edition, May 1987, Dow Chemical Company; Midland, Michigan 48674...Chemical Exposure Index,” May 1988, Dow Chemical Company; Midland, Michigan...

2010-07-01

223

29 CFR 1910.119 - Process safety management of highly hazardous chemicals.  

Science.gov (United States)

...control loops are usually shown along with key utilities on process flow diagrams...Classification Guide,” 6th Edition, May 1987, Dow Chemical Company; Midland, Michigan 48674...Chemical Exposure Index,” May 1988, Dow Chemical Company; Midland, Michigan...

2010-07-01

224

Trion ladder diagrams  

CERN Document Server

We first derive a new ``commutation technique'' for an exciton interacting with electrons, inspired from the one we recently developed for excitons interacting with excitons. These techniques allow to take \\emph{exactly} into account the possible exchanges between carriers. We use it to get the $\\mathrm{X}^-$ trion creation operator in terms of exciton and free-electron creation operators. In a last part we generate the ladder diagrams associated to these trions. Although similar to the exciton ladder diagrams, with the hole replaced by an exciton, they are actually much more tricky : (i) Due to the composite nature of the exciton, one cannot identify an exciton-electron potential similar to the Coulomb potential between electron and hole ; (ii) the spins are unimportant for excitons while they are crucial for trions, singlet and triplet states having different energies.

Combescot, M

2002-01-01

225

Peircean diagrams of time  

DEFF Research Database (Denmark)

Some very good arguments can be given in favor of the Augustinean wisdom, according to which it is impossible to provide a satisfactory definition of the concept of time. However, even in the absence of a proper definition, it is possible to deal with conceptual problems regarding time. It can be done in terms of analogies and metaphors. In particular, it is attractive to make use of Peirce's diagrams by means of which various kinds of conceptual experimentation can be carried out. This paper investigates how Peircean diagrams can be used within the study of time. In particular, we discuss 1) the topological properties of time, 2) the implicative structure in tense logic, 3) the notions of open future and branching time models, and finally 4) tenselogical alternatives to branching time models.

ØhrstrØm, Peter

2011-01-01

226

Control wiring diagrams  

International Nuclear Information System (INIS)

This paper discusses the changes in electrical document requirements that occur when construction is complete and a generating station starts commercial operation. The needs of operations and maintenance (O and M) personnel are analyzed and contrasted with those of construction to illustrate areas in which the construction documents (drawings, diagrams, and databases) are difficult to use for work at an operating station. The paper discusses the O and M electrical documents that the Arizona Nuclear Power Project (ANPP) believes are most beneficial for the three operating units at Palo Verde; these are control wiring diagrams and an associated document cross-reference list. The benefits offered by these new, station O and M-oriented documents are weighted against the cost of their creation and their impact on drawing maintenance

227

An Introduction to Tree Diagrams  

Science.gov (United States)

This brief article describes the use of tree diagrams in calculating probabilities. The author provides examples of how tree diagrams are used to calculate specific probabilities and why the language chosen relates to the operations used to find the probability.

Cork, Stu

2014-01-01

228

Physical model of fluid flow characteristics in RH-TOP vacuum refining process  

Science.gov (United States)

To understand the characteristic of circulation flow rate in 250-t RH-TOP vacuum refining process, the l:4 water model test was established through the bubble behavior and gas holdup in the up-leg to investigate the effects of different processes and equipment parameters on the RH circulation flow rate. With the increases of lifting gas flow rate, lifting bubble travel, and the internal diameter of the up-leg, and the decrease of nozzle diameter, the work done by bubble floatage and the circulation flow rate increase. The expression of circulation flow rate was derived from the regression analysis of experiment data. Meanwhile, the influences of vacuum chamber pressure and nozzle blockage situation on the circulation flow rate were discussed in detail by the bubble behavior and gas holdup in the up-leg. It is necessary to maintain a certain vacuum chamber liquid level in the molten steel circulation flow. Compared with a nozzle with symmetrical blockage in the up-leg, when a nozzle with non-symmetrical blockage is applied, the lifting gas distribution is non-uniform, causing a great effect on the molten steel circulation flow and making the circulation flow drop largely.

Lin, Lu; Bao, Yan-ping; Yue, Feng; Zhang, Li-qiang; Ou, Hong-lin

2012-06-01

229

Laminar flow and convective transport processes scaling principles and asymptotic analysis  

CERN Document Server

Laminar Flow and Convective Transport Processes: Scaling Principles and Asymptotic Analysis presents analytic methods for the solution of fluid mechanics and convective transport processes, all in the laminar flow regime. This book brings together the results of almost 30 years of research on the use of nondimensionalization, scaling principles, and asymptotic analysis into a comprehensive form suitable for presentation in a core graduate-level course on fluid mechanics and the convective transport of heat. A considerable amount of material on viscous-dominated flows is covered.A unique feat

Brenner, Howard

1992-01-01

230

Optimizing evacuation flow in a two-channel exclusion process  

CERN Document Server

We use a basic setup of two coupled exclusion processes to model a stylised situation in evacuation dynamics, in which evacuees have to choose between two escape routes. The coupling between the two processes occurs through one common point at which particles are injected, the process can be controlled by directing incoming individuals into either of the two escape routes. Based on a mean-field approach we determine the phase behaviour of the model, and analytically compute optimal control strategies, maximising the total current through the system. Results are confirmed by numerical simulations. We also show that dynamic intervention, exploiting fluctuations about the mean-field stationary state, can lead to a further increase in total current.

Galla, Tobias

2011-01-01

231

Conservative Generalized Bifurcation Diagrams  

OpenAIRE

Bifurcation cascades in conservative systems are shown to exhibit a generalized diagram, which contains all relevant informations regarding the location of periodic orbits (resonances), their width (island size), irrational tori and the infinite higher-order resonances, showing the intricate way they are born. Contraction rates for islands sizes, along period-doubling bifurcations, are estimated to be $\\alpha_I\\sim 3.9$. Results are demonstrated for the standard map and for ...

Manchein, Cesar; Beims, Marcus W.

2012-01-01

232

The Tinsley diagram revisited  

CERN Document Server

Motivated by the recent determinations of the Hubble constant (H_0) from observations of Cepheid variables in NGC4571 and M100, we plot the Tinsley diagram with level curves of the cosmological constant (\\Lambda). Based on current estimates of the absolute ages of globular clusters we conclude that \\Lambda > 0 and, irrespective of the background spatial curvature, the universe will not recollapse. These conclusions hold for both relativistic and Newtonian models and are {\\it independent} of the density parameter.

Leonard, S; Leonard, Stephen; Lake, Kayll

1995-01-01

233

Compressing Binary Decision Diagrams  

DEFF Research Database (Denmark)

The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1-2 bits per node. Empirical results for our compression technique are presented, including comparisons with previously introduced techniques, showing that the new technique dominate on all tested instances

Hansen, Esben Rune; Satti, Srinivasa Rao

2008-01-01

234

Compressing Binary Decision Diagrams  

CERN Document Server

The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1-2 bits per node. Empirical results for our compression technique are presented, including comparisons with previously introduced techniques, showing that the new technique dominate on all tested instances.

Hansen, Esben Rune; Tiedemann, Peter

2008-01-01

235

Process and device for measuring speed of flow and gas volume of a liquid metal flow  

International Nuclear Information System (INIS)

The magnetic probe immersed in the liquid metal flow (sodium) produces two voltages in two predetermined volumes on the Faraday induction principle, which are taken to two amplifiers. There is a correlator for determining the cross correlation function and the transport period. The outputs of the amplifiers are switched to a measuring instrument which responds quickly to determine the gas volume. The magnetic probe itself consists of a tube closed at one end, which is concentrically mounted in a jacket tube, and forms an annulus with this, through which the liquid metal flows. There are two disc-shaped permanent magnets made, for example, of AlNiCo 450 at a certain spacing from each other in the magnetic probe, and there are two pairs of electrodes associated with them. These give the voltage signals for the amplifiers. The material of the probes and the jacket tube is V2A. (HP)

236

Voronoi diagrams and their applications  

OpenAIRE

In these theses are pepresented the Voronoi diagram and Network Voronoi diagram. The shortest path Dijkstra’s algorithm was modified in this way that calculates shortest paths from several Voronoi generators at the same time. The first result - partition of the nodes of the network. The seond result - arcs of the network are attributed to the generators, considering especially their direction and asymmetric costs. Applications allow compare Network Voronoi diagrams to Voronoi diagrams. For ...

Z?vikaite?, Laura

2005-01-01

237

Flow Processes and Sedimentation Associated with Erosion and Filling of Sinuous Submarine Channels  

Science.gov (United States)

Sinuous submarine channels are common on all of Earth's siliciclastic continental margins. Approaches to studying flow processes and sedimentation of gravity flows in sinuous submarine channels is limited to direct measurements of the modern seafloor, physics-based numerical models, analytical solutions, physical experiments. While these approaches provide insight, no study documents distinctions in flow properties and sedimentation associated with erosion and filling of a natural sinuous submarine channel. Measurements from the modern seafloor cannot be used as their lifespan exceeds that of humans. Therefore, a sinuous submarine channel can not be monitored through its lifespan. However, outcrops of sinuous submarine channels and their fill contain a record of the erosional and depositional stages of the channel's evolution. The Beacon Channel of the Brushy Canyon Formation crops out on multiple cliff faces revealing two complete bends in the sinuous submarine channel. This study uses measurements from a 3D exposure to document how flow properties and sedimentation differ between erosional and filling stages of channels. Two units, recording the sequential evolution of the channel are documented. Unit 1 records gravity flows that deepened and laterally migrated the channel. These gravity flows were mud-rich with a wide grain-size distribution. Flow heights exceeded the depth of the channel resulting in the deposition of levees. Strong secondary flow is evident with a helical pattern reversed to subaerial channels. Point bars have coarsening upward grain-size profiles. Point bars and levees were deposited by tractive processes. Unit 2 records gravity flows that filled the channel. These gravity flows were sand-rich with a relatively narrow grain-size distribution. Flow heights scaled to the depth of the channel, and they contain no evidence for secondary flow. Associated strata are horizontal and deposited primarily from suspension.

Pyles, D. R.; Tomasso, M.; Jennette, D.

2011-12-01

238

Vista Data Flow System: Pipeline Processing for WFCAM and VISTA  

Science.gov (United States)

The UKIRT Wide Field Camera (WFCAM) on Mauna Kea and the VISTA IR mosaic camera at ESO, Paranal, with respectively 4 Rockwell 2k × 2k and 16 Raytheon 2k × 2k IR arrays on 4m-class telescopes, represent an enormous leap in deep IR survey capability. However with an expected data rate of an image of the sky every 5-30s and combined nightly data-rates of typically 1 TB, automated pipeline processing and data management requirements are paramount. Pipeline processing of IR data is far more technically challenging than for optical data. IR detectors are inherently more unstable, while the sky emission is over 100 times brighter than most objects of interest, and varies in a complex spatial and temporal manner. The pipelines are designed around a selectable modular scheme, driven by processing recipes for maximum flexibility. Our general philosophy is that all fundamental data products are in multi-extension FITS files with headers describing the data taking protocols in sufficient detail to trigger the appropriate pipeline processing components. All derived information, DQC, photometric and astrometric calibration and processing details are also incorporated into the FITS headers. Generated catalogues are stored in FITS binary tables. The headers provide a basis for ingest into databases for archiving, real time monitoring of survey progress and survey planning. To reduce the data storage I/O overheads and transport requirements, we intend to use, as much as possible, the lossless Rice tile compression scheme as used transparently, for example, in CFITSIO. For this type of data (32 bit integer) the algorithm typically gives a factor of 3-4 compression

Lewis, J. R.; Irwin, M. J.; Hodgkin, S. T.; Bunclark, P. S.; Evans, D. W.; McMahon, R. G.

2005-12-01

239

An Improved Experimental Method for Simulating Erosion Processes by Concentrated Channel Flow  

OpenAIRE

Rill erosion is an important process that occurs on hill slopes, including sloped farmland. Laboratory simulations have been vital to understanding rill erosion. Previous experiments obtained sediment yields using rills of various lengths to get the sedimentation process, which disrupted the continuity of the rill erosion process and was time-consuming. In this study, an improved experimental method was used to measure the rill erosion processes by concentrated channel flow. By using this met...

Chen, Xiao-yan; Zhao, Yu; Mo, Bin; Mi, Hong-xing

2014-01-01

240

Some Remarks on Non-Planar Diagrams  

CERN Document Server

Two criteria for planarity of a Feynman diagram upon its propagators (momentum flows) are presented. Instructive Mathematica programs that solve the problem and examples are provided. A simple geometric argument is used to show that while one can planarize non-planar graphs by embedding them on higher-genus surfaces (in the example it is a torus), there is still a problem with defining appropriate dual variables since the corresponding faces of the graph are absorbed by torus generators.

Bielas, Krzysztof; Gluza, Janusz; Riemann, Tord

2013-01-01

241

Stochastic flows, reaction-diffusion processes, and morphogenesis  

International Nuclear Information System (INIS)

Recently, an exact procedure has been introduced [C. A. Walsh and J. J. Kozak, Phys. Rev. Lett.. 47: 1500 (1981)] for calculating the expected walk length for a walker undergoing random displacements on a finite or infinite (periodic) d-dimensional lattice with traps (reactive sites). The method (which is based on a classification of the symmetry of the sites surrounding the central deep trap and a coding of the fate of the random walker as it encounters a site of given symmetry) is applied here to several problems in lattice statistics for each of which exact results are presented. First, we assess the importance of lattice geometry in influencing the efficiency of reaction-diffusion processs in simple and multiple trap systems by reporting values of for square (cubic) versus hexagonal lattices in d = 2,3. We then show how the method may be applied to variable-step (distance-dependent) walks for a single walker on a given lattice and also demonstrate the calculation of the expected walk length for the case of multiple walkers. Finally, we make contact with recent discussions of ''mixing'' by showing that the degree of chaos associated with flows in certain lattice-systems can be calibrated by monitoring the lattice walks induced by the Poincare map of a certain parabolic function

242

Multilayer roll bonded aluminium foil: processing, microstructure and flow stress  

International Nuclear Information System (INIS)

Bulk aluminium has been produced by warm-rolling followed by cold-rolling of commercial purity (99% purity) aluminium foil. The bonding appeared perfect from observation with the naked eye, light and transmission electron microscopy. By comparison with bulk aluminium of similar purity (AA1200) rolled to a similar strain (90%RA), the roll-bonded metal showed a much higher density of high-angle grain boundaries, similar strength and improved thermal stability. This study has implications for a number of applications in relation to the processing of aluminium. Roll bonding is of interest as a method for grain size refinement; oxide-containing materials have increased strength, enhanced work-hardening behaviour, and exhibit alterations in recrystallisation behaviour. The behaviour of the hard oxide film is of interest in aluminium processing, and has been investigated by characterising the size and distribution of oxide particles in the roll-bonded samples

243

Study on Flow Stress Model and Processing Map of Homogenized Mg-Gd-Y-Zn-Zr Alloy During Thermomechanical Processes  

Science.gov (United States)

Quantities of billets were compressed with 50% height reduction on a hot process simulator to study the plastic flow behaviors of homogenized as-cast Mg-13Gd-4Y-2Zn-0.6Zr alloy. The test alloy was heat treated at 520 °C for 12 h before thermomechanical experiments. The temperature of the processes ranged from 300 to 480 °C. The strain rate was varied between 0.001 and 0.5 s-1. According to the Arrhenius type equation, a flow stress model was established. In this model, flow stress was regarded as the function of the stress peak, strain peak, and the strain. A softening factor was used to characterize the dynamic softening phenomenon that occurred in the deformation process. Meanwhile, the processing maps based on the dynamic material modeling were constructed. The optimum temperature and strain rate for hot working of the test alloy were 480 °C and 0.01 s-1, respectively. Furthermore, the flow instability occurred in the two areas where the temperature ranged from 350 to 480 °C at strain rate of 0.01-0.1 s-1, and the temperature ranged from 450 to 480 °C with a strain rate of 0.1 s-1. According to the determined hot deformation parameters, four components were successfully formed, and the ultimate tensile strength, yield strength, and elongation of the component were 386 MPa, 331 MPa, and 6.3%, respectively.

Xue, Yong; Zhang, Zhimin; Lu, Guang; Xie, Zhiping; Yang, Yongbiao; Cui, Ya

2014-11-01

244

Variable heat-flow patterns and hydrothermal processes near the Mid-Atlantic Ridge  

Science.gov (United States)

Oceanic heat-flow is commonly affected by water circulation. The primary mechanism was identified by Lister (1972) near the Juan de Fuca ridge (NE Pacific) and attributed to hydrothermal flow within the oceanic basement: sea-water recharges at certain seamounts, flows within the high-permeability basement below the sediments and discharges at other seamounts. As a result, the heat-flow measured at the ocean bottom is significantly lower than expected for a conductively cooling lithosphere, as long as the fluid is not in equilibrium with the host rock. But this is not the only mechanism for low heat-flow values in the oceanic lithosphere: near the Mid-Atlantic ridge, Langseth et al (1992) have identified the process of sea-water drawdown into the sediments. Here we present results from a recent heat-flow survey (OCEANOGRAFLU, June 2013) on the Mid-Atlantic Ridge flanks at about 35°N, close to the Oceanographer fracture zone, where we have observed similar evidences that sea-water can flow directly into the surficial sediments. Where the heat-flow is lower than the conductive cooling values, the temperature-depth profiles are systematically non-linear, showing sigmoid shapes or negative gradients, and the sediment porewaters have compositions close to that of sea-water. No clear evidence for basement recharge or discharge is observed, which differs significantly from the results of a previous study 400 km North, where the heat-flow pattern was more consistent with water flowing into the oceanic basement rather than into the sediment (Lucazeau et al, 2006). We will present the relevant observations and examine the possible causes for the different processes affecting the heat-flow in the Mid-Atlantic Ridge flanks.

Lucazeau, Francis

2014-05-01

245

An experimental investigation of steam-water flow in direct condensation process  

International Nuclear Information System (INIS)

Direct contact condensation processes of mixing streams at high speed ratio are observed within condensing ejector and ECCS of reactor etc. In this paper, the pressure fluctuations of steam-water flow in direct condensation process are treated with especially at high speed ratio(Wv/Wl = 500 - 1200). The characteristics of their pressure fluctuations are analysed by PDF(Probability Density Function) and FFT(Fast Fourier Trabaform). The results are shown that the variance of PDF depends on the flow characteristics and there exists the frequency peak caused by condensing process. (author)

246

A self-sustaining nonlinear dynamo process in Keplerian shear flows  

CERN Document Server

A three-dimensional nonlinear dynamo process is identified in rotating plane Couette flow in the Keplerian regime. It is analogous to the hydrodynamic self-sustaining process in non-rotating shear flows and relies on the magneto-rotational instability of a toroidal magnetic field. Steady nonlinear solutions are computed numerically for a wide range of magnetic Reynolds numbers but are restricted to low Reynolds numbers. This process may be important to explain the sustenance of coherent fields and turbulent motions in Keplerian accretion disks, where all its basic ingredients are present.

Rincon, F; Proctor, M R E

2007-01-01

247

Processing the ground vibration signal produced by debris flows: the methods of amplitude and impulses compared  

Science.gov (United States)

Ground vibration sensors have been increasingly used and tested, during the last few years, as devices to monitor debris flows and they have also been proposed as one of the more reliable devices for the design of debris flow warning systems. The need to process the output of ground vibration sensors, to diminish the amount of data to be recorded, is usually due to the reduced storing capabilities and the limited power supply, normally provided by solar panels, available in the high mountain environment. There are different methods that can be found in literature to process the ground vibration signal produced by debris flows. In this paper we will discuss the two most commonly employed: the method of impulses and the method of amplitude. These two methods of data processing are analyzed describing their origin and their use, presenting examples of applications and their main advantages and shortcomings. The two methods are then applied to process the ground vibration raw data produced by a debris flow occurred in the Rebaixader Torrent (Spanish Pyrenees) in 2012. The results of this work will provide means for decision to researchers and technicians who find themselves facing the task of designing a debris flow monitoring installation or a debris flow warning equipment based on the use of ground vibration detectors.

Arattano, M.; Abancó, C.; Coviello, V.; Hürlimann, M.

2014-12-01

248

Micro-particle image velocimetry measurement of blood flow: validation and analysis of data pre-processing and processing methods  

International Nuclear Information System (INIS)

The intent of this paper is to investigate the application of a pre-processing method previously validated on glycerol to blood flows in microchannels and to compare the accuracy of results obtained when applied to a non-homogeneous fluid such as blood with results from previously applied processing methods for blood data. Comparisons of common processing methods are desired for a clear measure of accuracy in order to make recommendations for various flows. It is hypothesized that increasing the correlation window overlap improves the profile prediction. The amount of correlation window overlap and window shape in the processing of data have a significant effect on the results. Image pre-processing is explored to improve the correlation using the ‘image overlapping’ which is extended to the case of blood and the blood-specific pre-processing ‘base-clipping’ or ‘thresholding’ technique currently applied to blood. Both pre-processing methods are tested with multiple processing methods for two channel geometries: a straight rectangular channel and a Y-channel resulting in a controlled shear flow. The resulting profiles and calculations demonstrate that ‘image-overlapping’ is found to achieve a profile closer to the predicted theoretical profile than current blood pre-processing methods when both are applied to the same set of data and both are superior to conventional cross-correlation on its own. In all cases, pre-processing decreases the smoothness of the predicted profile. The use of ‘image-overlapping’ is shown to have greater accuracy when calculating the shear rate at the wall of the channel as well. (paper)

249

Conservative generalized bifurcation diagrams  

International Nuclear Information System (INIS)

Bifurcation cascades in conservative systems are shown to exhibit a generalized diagram, which contains all relevant informations regarding the location of periodic orbits (resonances), their width (island size), irrational tori and the infinite higher-order resonances, showing the intricate way they are born. Contraction rates for islands sizes, along period-doubling bifurcations, are estimated to be ?I?3.9. Results are demonstrated for the standard map and for the continuous Hénon–Heiles potential. The methods used here are very suitable to find periodic orbits in conservative systems, and to characterize the regular, mixed or chaotic dynamics as the nonlinear parameter is varied.

250

Conservative generalized bifurcation diagrams  

Energy Technology Data Exchange (ETDEWEB)

Bifurcation cascades in conservative systems are shown to exhibit a generalized diagram, which contains all relevant informations regarding the location of periodic orbits (resonances), their width (island size), irrational tori and the infinite higher-order resonances, showing the intricate way they are born. Contraction rates for islands sizes, along period-doubling bifurcations, are estimated to be ?{sub I}?3.9. Results are demonstrated for the standard map and for the continuous Hénon–Heiles potential. The methods used here are very suitable to find periodic orbits in conservative systems, and to characterize the regular, mixed or chaotic dynamics as the nonlinear parameter is varied.

Manchein, Cesar, E-mail: cmanchein@gmail.com [Departamento de Física, Universidade do Estado de Santa Catarina, 89219-710 Joinville (Brazil); Beims, Marcus W., E-mail: mbeims@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, 81531-980 Curitiba (Brazil)

2013-04-01

251

Post-Processing of Discrete Flow Field Data for Particle Tracking Velocimetry  

Directory of Open Access Journals (Sweden)

Full Text Available To measure the surface flow in a physical river model, a brief introduction was given to the method of Particle Tracking Velocimetry (PTV. According to the characteristics of PTV by seeding particles on the water surface, particle images can be captured by CCD cameras and recognized by image division. PTV algorithm gives one vector for each particle based on the principle the trajectory of an individual particle is continuous. The key problem of analyzing the flow speed field accurately is post-processing of discrete flow field data. Errors of measurement discrete data are removed by the basic law of water movement. To attain the whole flow speed field, the methods of interpolation of discrete flow field data were proposed. In addition, the graphics of streamlines, velocity isolines and vortex isolines were drawn by the theory of hydraulic calculation.

Wang Pengtao

2013-01-01

252

Non-Linear Flow Process (NLFP): a new package implementing the Forchheimer equation in MODFLOW  

Science.gov (United States)

Groundwater flow in porous media is usually considered to be laminar and to follow Darcy's law (i.e. a linear relationship between the specific discharge and the hydraulic gradient). However, flow can become non-linear or turbulent if a critical Reynolds number is exceeded. This is known to occur, for example, within the solution conduits of karst aquifers or in the vicinity of pumping wells. As most of the existing distributive groundwater models such as MODFLOW-2005 are based on Darcy's law, there is a lack of tools accounting for the non-linear or turbulent flow conditions encountered in these settings. For this reason, a new MODFLOW package (Non-Linear Flow Process; NLFP) simulating non-linear flow following the Forchheimer equation was developed and implemented in MODLFOW-2005. This package is essentially based on an iterative modification of the linear conductance used by MODFLOW. The resulting effective Forchheimer conductance decreases with increasing specific discharge and thus mimics the effect of the non-linear term of the Forchheimer equation. The method was implemented such that the different layer types, boundaries conditions, and solvers as well as the wetting capability of MODFLOW are supported. The NLFP package was also successfully integrated in the current version of the conduit flow process CFP (Shoemaker et al., U.S. Geological Survey Techniques and Methods 6-A24, 2008). The correct implementation of the package is demonstrated using three different benchmark scenarios for which analytical solutions are available. Finally, a scenario considering transient flow in a more realistic karst setting and a larger model grid demonstrates that NLFP performs well under more complex conditions, although it converges moderately slower than the standard MODFLOW depending on the non-linearity of flow. Thus, this new tool opens a field of opportunities to non-linear groundwater flow simulation with MODFLOW-2005, especially for core sample simulation or vuggy karstified aquifers as well as for non-linear flow in vicinity of pumping wells.

Mayaud, Cyril; Walker, Patrica; Hergarten, Stefan; Birk, Steffen

2014-05-01

253

Effect of Inlet and Outlet Flow Conditions on Natural Gas Parameters in Supersonic Separation Process  

OpenAIRE

A supersonic separator has been introduced to remove water vapour from natural gas. The mechanisms of the upstream and downstream influences are not well understood for various flow conditions from the wellhead and the back pipelines. We used a computational model to investigate the effect of the inlet and outlet flow conditions on the supersonic separation process. We found that the shock wave was sensitive to the inlet or back pressure compared to the inlet temperature. The shock position s...

Yang, Yan; Wen, Chuang; Wang, Shuli; Feng, Yuqing

2014-01-01

254

Expanding the toolbox of asymmetric organocatalysis by continuous-flow process.  

Science.gov (United States)

Despite all the organic chemistry reaction methodologies already developed for the continuous-flow process, asymmetric synthesis is one that has gained less attention. Since the pioneering work of Barbas and MacMillan, organocatalysis has emerged as the third pillar of asymmetric catalysis. In this review, we present a survey of literature regarding the use of organocatalysis under continuous-flow conditions. PMID:25585518

Finelli, Fernanda G; Miranda, Leandro S M; de Souza, Rodrigo O M A

2015-02-17

255

Process of radiation chlorination of benzene in the continuous flow system  

International Nuclear Information System (INIS)

The process of radiation chlorination of benzene was studied in the continuous flow system. The influence of the following parameters: the flow rate of benzene, irradiation dose, concentration of chlorine in benzene, temperature and the dose rate on the rate of reaction and the composition of the obtained product was determined. Comparative experiments with the solvents: dichloromethane and tetrachloroethane were also carried out. A possibility of the industrial application of the method is discussed. 6 refs., 2 figs., 2 tabs. (author)

256

POWER FLOW ANALYSIS OF A CONTINUOUS PROCESS PLANT: (A CASE STUDY)  

OpenAIRE

For the continuous evaluation of the performance of the power system, power flow solutions are essential for exhibiting suitable control actions in case of requirement. This case study presents analysis of the electrical power system of continuous process plant having its own captive generation along with the provision of the Grid connectivity. The different power system elements are modeled as per the manufacturer’s data sheet. To evaluate the steady state performance, power flow simulatio...

Smita Acharya, Pragati Gupta

2013-01-01

257

Analysis of nuclear material flow for experimental DUPIC fuel fabrication process at DFDF  

Energy Technology Data Exchange (ETDEWEB)

This report describes facilities necessary for manufacturing experiment for DUPIC fuel, manufacturing process and equipment. Nuclear material flows among facilities, in PIEF and IMEF, for irradiation test, for post examination of DUPIC fuel, for quality control, for chemical analysis and for treatment of radioactive waste have been analyzed in details. This may be helpful for DUPIC project participants and facility engineers working in related facilities to understand overall flow for nuclear material and radioactive waste. (Author). 14 refs., 15 tabs., 41 figs.

Lee, H. H.; Park, J. J.; Shin, J. M.; Lee, J. W.; Yang, M. S.; Baik, S. Y.; Lee, E. P

1999-08-01

258

Taming hazardous chemistry in flow: the continuous processing of diazo and diazonium compounds.  

Science.gov (United States)

The synthetic utilities of the diazo and diazonium groups are matched only by their reputation for explosive decomposition. Continuous processing technology offers new opportunities to make and use these versatile intermediates at a range of scales with improved safety over traditional batch processes. In this minireview, the state of the art in the continuous flow processing of reactive diazo and diazonium species is discussed. PMID:25404044

Deadman, Benjamin J; Collins, Stuart G; Maguire, Anita R

2015-02-01

259

Materials And Carbon Flow In A Waste Refinery Process Using Enzymes  

OpenAIRE

Recovery of resources from mixed Municipal Solid Waste (MSW) is a crucial aspect of waste management practices. In this paper the materials and carbon flows of an innovative waste refinery process using enzymes are presented. Through enzymatic treatment the process produces two main streams from the initial mixed MSW: a bioslurry (liquefied paper and organics) and a solid fraction (non-degradable materials). The discussion is based on the performance of the process in separating recyclables a...

Tonini, Davide; Woods, M.; Astrup, Thomas

2011-01-01

260

Preliminary flashing multiphase flow analysis with application to letdown valves in coal-conversion processes  

Energy Technology Data Exchange (ETDEWEB)

As part of the Oak Ridge National Laboratory's technical support to large coal liquefaction projects, attempts have been made to (1) develop the methodology for characterizing and predicting multicomponent, multiphase, non-Newtonian flow behavior within letdown valves and devices, and (2) analyze the fluid flow in the entire letdown region of the process. An engineering model that can be used in the analysis of multicomponent, multiphase, flashing, flowing systems has been developed. A preliminary version of a user-oriented computer code for this model has been developed and is fully described.

Ott, L. J.; Khan, A. A.

1982-09-01

261

Map estimation of air-flow dipole source positions using array signal processing  

OpenAIRE

In nature, fish have the ability to form flow-based maps to assist localizing predator or prey using the lateral-line system. Yet it is not fully understood what techniques are used by fish to draw these flow maps. Biologists try to figure out fish techniques by investigating different hypotheses [1]. Inspired by the lateral line of fish, we propose in this paper model based array signal processing techniques used to visualize the air-flow maps. The results show an ability to visualize the fl...

Dagamseh, A. M. K.; Krijnen, G. J. M.

2010-01-01

262

Development of an Industrial SPECT to Study Dynamic Behavior of Plant Process Flow  

International Nuclear Information System (INIS)

Radioisotope technologies are currently widely used to investigate the spatial distribution, flow pattern, and mixing characteristics of process media. It is still, however, a great challenge to obtain a satisfactory result for a multiphase flow that can be easily found in a refinery, petrochemical plant. The radioactive particle tracking (RPT) technique was recently proposed as a promising method, which can, however, supply only very limited information on the flow dynamics. Legoupil et al. developed an industrial single photon emission computed tomography (SPECT) and applied it to visualizing the flow dynamics of a process system. The industrial SPECT allows a real-time analysis of flow distribution based on the distribution of radioactive tracer injected in the system. In the present study, several different geometries of the industrial SPECT were evaluated for imaging a labscale flow system by the Monte Carlo method, in terms of imaging quality for a 99mTc gamma radiation source. Based on the test results, an optimal geometry of the imaging system was determined for imaging the lab-scale flow system

263

Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors  

Energy Technology Data Exchange (ETDEWEB)

The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach the equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and also to compare with equilibrium batch experiments for CyMe{sub 4}- BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, around 8% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). The general conclusion is that the development of a process flow sheet needs investigation of the kinetic behaviour in the actual equipment used. (authors)

Magnusson, D. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340 D-76125 Karlsruhe (Germany)]|[Chalmers University of Technology, Nuclear Chemistry, Deparment of Chemical and Biological Engineering, Gothenburg (Sweden); Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340 D-76125 Karlsruhe (Germany); Modolo, G. [Forschungszentrum Juelich, Institute for Energy Research, Safety Research and Reactor Technology, D-52425 Juelich (Germany); Sorel, C. [Commissariat a l' Energie Atomique Valrho (CEA), DRCP/SCPS, BP17171, 30207 Bagnols-sur-Ceze (France)

2008-07-01

264

Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors  

International Nuclear Information System (INIS)

The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach the equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and also to compare with equilibrium batch experiments for CyMe4- BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, around 8% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). The general conclusion is that the development of a process flow sheet needs investigation of the kinetic behaviour in the actual equipment used. (authors)

265

Using Eye Tracking to Investigate Semantic and Spatial Representations of Scientific Diagrams During Text-Diagram Integration  

Science.gov (United States)

We investigated strategies used by readers when reading a science article with a diagram and assessed whether semantic and spatial representations were constructed while reading the diagram. Seventy-one undergraduate participants read a scientific article while tracking their eye movements and then completed a reading comprehension test. Our results showed that the text-diagram referencing strategy was commonly used. However, some readers adopted other reading strategies, such as reading the diagram or text first. We found all readers who had referred to the diagram spent roughly the same amount of time reading and performed equally well. However, some participants who ignored the diagram performed more poorly on questions that tested understanding of basic facts. This result indicates that dual coding theory may be a possible theory to explain the phenomenon. Eye movement patterns indicated that at least some readers had extracted semantic information of the scientific terms when first looking at the diagram. Readers who read the scientific terms on the diagram first tended to spend less time looking at the same terms in the text, which they read after. Besides, presented clear diagrams can help readers process both semantic and spatial information, thereby facilitating an overall understanding of the article. In addition, although text-first and diagram-first readers spent similar total reading time on the text and diagram parts of the article, respectively, text-first readers had significantly less number of saccades of text and diagram than diagram-first readers. This result might be explained as text-directed reading.

Jian, Yu-Cin; Wu, Chao-Jung

2015-02-01

266

Online traffic flow model applying dynamic flow-density relation  

International Nuclear Information System (INIS)

This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic flow is simplified and classified into three traffic states depending on the propagation of congestion. The traffic states are represented on a phase diagram with the upstream demand axis and the interaction strength axis which was defined in this research. The states diagram and the phase diagram provide a basis for the development of the dynamic flow-density relation. The first-order hydrodynamic traffic flow model was programmed according to the cell-transmission scheme extended by the modification of flow dependent sending/receiving functions, the classification of cells and the determination strategy for the flow-density relation in the cells. The unreasonable results of macroscopic traffic flow models, which may occur in the first and last cells in certain conditions are alleviated by applying buffer cells between the traffic data and the model. The sending/receiving functions of the cells are determined dynamically based on the classification of the traffic states by employing fuzzy logic and the shock wave theory. The model is extended to describe also the propagation of congestion in the motorway sections with ramps by considering the capacity reduction caused by the interaction between the traffic flow of the mainstream and the ramps. This research represents the potential of the macroscopic traffic flow models for the application to online traffic control systems by applying the dynamic flow-density relation. The new modelling approach alleviates a critical problem, i.e. the parameter calibration problem, of existing traffic flow models. (orig.)

267

Gas/slurry flow in coal-liquefaction processes (fluid dynamics in 3-phase flow column)  

Energy Technology Data Exchange (ETDEWEB)

This work is a continuation of studies on the fluid dynamics of 3-phase flow to support the design of the 6000 T/D dissolver for the SRC-I demonstration plant. This plant will employ vertical tubular reactors feeding slurry and gas concurrently upward through these vessels. This reactor is essentially an empty vessel with only a distributor plate located near the inlet. Because the commercial plant represents a considerable scale-up, this program is addressing the need for additional data on behavior of three phase systems in large vessels. Parameters are being studied at conditions that relate directly to the projected demonstration plant operating conditions. The results show that the liquid axial dispersion coefficient was independent of liquid velocity regardless of the presence of solids, the solids concentration and their particle size. Increasing gas velocity, however, increased the liquid dispersion coefficient in all conditions. All the results clearly indicated a decrease in liquid dispersion coefficient as well as liquid backmixing in the presence of solid particles. The predicted axial dispersion coefficients from this correlation agree reasonably well with our experimental values for the air/water system.

Ying, D. H.S.; Sivasubramanian, R.; Givens, E. N.

1980-05-01

268

Using turbine expanders to recover exothermic reaction heat--flow sheet development for typical chemical processes  

International Nuclear Information System (INIS)

The integration of a turbine expander into different types of high pressure, exothermic chemical synthesis processes is considered. In conventional systems, the reaction heat is often transferred to generate steam to drive steam turbines or used for heat integration. The heat is reduced in quality due to the temperature driving forces in the heat exchange equipment. Reaction heat can be utilised at the maximum possible temperature by placing a turbine expander directly after the reactor. The power generated from such combined power and chemical systems can either be exported or used to satisfy the process compressor requirements. A methodology is presented to lend structure to the development and analysis of the flow sheets for the mentioned systems. The methodology involves the consideration of various factors that were identified to impact on the flow sheet development. These factors are discussed and a brief overview of the flow sheet development for four different case studies is given. Process data generated from simulations are used

269

Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing  

Directory of Open Access Journals (Sweden)

Full Text Available The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.

Cally Gill

2013-09-01

270

Continuous-Flow Processes in Heterogeneously Catalyzed Transformations of Biomass Derivatives into Fuels and Chemicals  

Directory of Open Access Journals (Sweden)

Full Text Available Continuous flow chemical processes offer several advantages as compared to batch chemistries. These are particularly relevant in the case of heterogeneously catalyzed transformations of biomass-derived platform molecules into valuable chemicals and fuels. This work is aimed to provide an overview of key continuous flow processes developed to date dealing with a series of transformations of platform chemicals including alcohols, furanics, organic acids and polyols using a wide range of heterogeneous catalysts based on supported metals, solid acids and bifunctional (metal + acidic materials.

Antonio A. Romero

2012-07-01

271

A new enabling technology for convenient laboratory scale continuous flow processing at low temperatures.  

Science.gov (United States)

A new machine for conducting continuous flow processes at low temperatures on a laboratory scale is reported. The use of this cryogenic flow reactor has been demonstrated by the preparation of a variety of (hetero)aromatic boronic acids and esters via lithium halogen exchange chemistry. Furthermore, scale-up of the reaction conditions not only demonstrates the application of this device for the preparation of useful building blocks but also combines the ability to process n-butyllithium directly through pump heads attached to the unit. PMID:21615126

Browne, Duncan L; Baumann, Marcus; Harji, Bashir H; Baxendale, Ian R; Ley, Steven V

2011-07-01

272

Sintering diagrams of UO2  

International Nuclear Information System (INIS)

Ashby's method (see Acta Met., vol. 22, p. 275, 1974) of constructing sintering diagrams has been modified to obtain contribution diagrams directly from the computer. The interplay of sintering variables and mechanisms are studied and the factors that affect the participation of mechanisms in UO2 are determined. By studying the physical properties, it emerges that the order of inaccuracies is small in most cases and do not affect the diagrams. On the other hand, even a 10% error in activation energies, which is quite plausible, would make a significant difference to the diagram. The main criticism of Ashby's approach is that the numerous properties and equations used, communicate their inaccuracies to the diagrams and make them unreliable. The present study has considerably reduced the number of factors that need to be refined to make the sintering diagrams more meaningful. (Auth.)

273

FPGA Implementations of Ladder Diagrams  

Directory of Open Access Journals (Sweden)

Full Text Available The performance of programmable logic controllers is often constrained by the microprocessor and the real-time firmware of the controller. Field programmable gate arrays (FPGAs are an attractive potential implementation medium for high-speed control because of their fast and parallel execution and programmable nature. Ladder Diagrams are a standard graphical programming method for industrial controllers, but compilers from Ladder Diagrams to FPGA hardware do not yet exist. This paper explores the comparative speed of four different classes of FGPA implementation of Ladder Diagrams - Interpreted Software, Compiled Software, Interpreted Hardware and Compiled Hardware. It also explores parallel versus serial execution of Ladder Diagrams in hardware, and identifies timers as a major resource user in parallel implementations. Overall, a Shared Timer Serial Compiled Hardware system for FPGA implementation of Ladder Diagrams is recommended. Using comparable FPGA resources to other alternatives it provides a 20-600 times speed improvement over other solutions whilst maintaining correct Ladder Diagram semantics.

Neil William Bergmann

2013-02-01

274

Case study: Class diagram restructuring  

OpenAIRE

This case study is an update-in-place refactoring transformation on UML class diagrams. Its aim is to remove clones of attributes from a class diagram, and to identify new classes which abstract groups of classes that share common data features. It is used as one of a general collection of transformations (such as the removal of redundant inheritance, or multiple inheritance) which aim to improve the quality of a specification or design level class diagram. The transf...

Lano, K.; Kolahdouz Rahimi, S.

2013-01-01

275

PROBLEMS AND TERMS OF THE IMPLEMENTATION OF OPTIMAL FLOW PROCESSES MANAGEMENT  

Directory of Open Access Journals (Sweden)

Full Text Available The relevance of the logistics concept concerning the solution of flow processes optimal control problems of industrial enterprises is discussed in the article. Modern tools of logistics make it possible to resolve the existing contradictions in Ukrainian economy by unifying business-structures into a single efficient system.While dealing with enterprise optimal management as a total combination of flow processes, logistics plays the main role as a regulator between an enterprise and resources market on the one hand, and an enterprise and sales market of finished goods on the other hand. Thus, there is a constant exchange (supply of matter, energy and information between the links of a continuous chain (supply chain.Such a definition as "variability" is suggested as a fundamental reason of inconsistency. The concept of variability is explained as any deviation at input / output processes from the desired ideal values. From this points of view the fundamental way to improve system efficiency is to reduce this variability.The current management of an enterprise should take into consideration integration and innovation aspects of economy. It should be based on consistency and compliance of flow processes of an enterprise, and be predictive. The conditions for implementation of optimal (logistics management of flow processes were outlined.

I. Dzobko

2012-06-01

276

Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors  

Energy Technology Data Exchange (ETDEWEB)

The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe{sub 4}-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed. (orig.)

Magnusson, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Chalmers Univ. of Technology, Gothenburg (Sweden). Nuclear Chemistry, Dept. of Chemical and Biological Engineering; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Modolo, G. [Forschungszentrum Juelich GmbH (Germany). Inst. for Energy Research, Safety Research and Reactor Technology; Sorel, C. [Commissariat a l' Energie Atomique Valrho (CEA), DRCP/SCPS, Bagnols-sur-Ceze (France)

2009-07-01

277

Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors  

International Nuclear Information System (INIS)

The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe4-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed. (orig.)

278

Modeling Unsaturated Flow and Transport Processes in Fractured Tuffs of Yucca Mountain  

International Nuclear Information System (INIS)

This paper presents a field modeling study characterizing fluid flow and tracer transport in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository for storing high-level radioactive waste. The 500 to 700 meter thick unsaturated zone of Yucca Mountain consists of highly heterogeneous layers of anisotropic, fractured ash flow and air fall tuffs. Characterization of fluid flow and heat transfer through such a system has been a challenge due to the heterogeneities prevalent on various scales. Quantitative evaluation of water, gas, and heat flow by means of numerical simulation is essential for design and performance assessment of the repository. A three-dimensional numerical flow and transport model will be discussed. The model has been calibrated against field-measured data and takes into account the coupled processes of unsaturated flow and tracer transport in the highly heterogeneous, unsaturated fractured porous rock. The modeling approach of the model is based on a dual-continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. As application examples, effects of current and future climates on the unsaturated zone processes are evaluated to aid in the assessment of the proposed repository's system performance

279

Modeling studies for multiphase fluid and heat flow processes in nuclear waste isolation  

International Nuclear Information System (INIS)

Multiphase fluid and heat flow plays an important role in many problems relating to the disposal of nuclear wastes in geologic media. Examples include boiling and condensation processes near heat-generating wastes, flow of water and formation gas in partially saturated formations, evolution of a free gas phase from waste package corrosion in initially water-saturated environments, and redistribution (dissolution, transport, and precipitation) of rock minerals in non-isothermal flow fields. Such processes may strongly impact upon waste package and repository design considerations and performance. This paper summarizes important physical phenomena occurring in multiphase and nonisothermal flows, as well as techniques for their mathematical modeling and numerical simulation. Illustrative applications are given for a number of specific fluid and heat flow problems, including: thermohydrologic conditions near heat-generating waste packages in the unsaturated zone; repository-wide convection effects in the unsaturated zone; effects of quartz dissolution and precipitation for disposal in the saturated zone; and gas pressurization and flow corrosion of low-level waste packages. 34 refs; 7 figs; 2 tabs

280

Behind the folding funnel diagram.  

Science.gov (United States)

This Commentary clarifies the meaning of the funnel diagram, which has been widely cited in papers on protein folding. To aid in the analysis of the funnel diagram, this Commentary reviews historical approaches to understanding the mechanism of protein folding. The primary role of free energy in protein folding is discussed, and it is pointed out that the decrease [corrected] in the configurational entropy as the native state is approached hinders folding, rather than guiding it. Diagrams are introduced that provide a less ambiguous representation of the factors governing the protein folding reaction than the funnel diagram. PMID:21685880

Karplus, Martin

2011-07-01

281

A pseudo-haptic knot diagram interface  

Science.gov (United States)

To make progress in understanding knot theory, we will need to interact with the projected representations of mathematical knots which are of course continuous in 3D but significantly interrupted in the projective images. One way to achieve such a goal would be to design an interactive system that allows us to sketch 2D knot diagrams by taking advantage of a collision-sensing controller and explore their underlying smooth structures through a continuous motion. Recent advances of interaction techniques have been made that allow progress to be made in this direction. Pseudo-haptics that simulates haptic effects using pure visual feedback can be used to develop such an interactive system. This paper outlines one such pseudo-haptic knot diagram interface. Our interface derives from the familiar pencil-and-paper process of drawing 2D knot diagrams and provides haptic-like sensations to facilitate the creation and exploration of knot diagrams. A centerpiece of the interaction model simulates a "physically" reactive mouse cursor, which is exploited to resolve the apparent conflict between the continuous structure of the actual smooth knot and the visual discontinuities in the knot diagram representation. Another value in exploiting pseudo-haptics is that an acceleration (or deceleration) of the mouse cursor (or surface locator) can be used to indicate the slope of the curve (or surface) of whom the projective image is being explored. By exploiting these additional visual cues, we proceed to a full-featured extension to a pseudo-haptic 4D visualization system that simulates the continuous navigation on 4D objects and allows us to sense the bumps and holes in the fourth dimension. Preliminary tests of the software show that main features of the interface overcome some expected perceptual limitations in our interaction with 2D knot diagrams of 3D knots and 3D projective images of 4D mathematical objects.

Zhang, Hui; Weng, Jianguang; Hanson, Andrew J.

2011-01-01

282

Geo-Hydro Statistical Characterization of Preferential Flow and Transport Processes in Karst Groundwater Systems  

Science.gov (United States)

Karst groundwater systems are highly productive and provide an important fresh water resource for human development and ecological integrity. Their high productivity is often associated with conduit flow and high matrix permeability. The same characteristics that make these aquifers productive also make them highly vulnerable to contamination and a likely for contaminant exposure. Of particular interest are chlorinated organic contaminants and phthalates derived from industrial solvents and plastic by-products. These chemicals have been identified as potential precursors of pre-term birth, a leading cause of neonatal complications with a significant health and societal cost. The general objectives of this work are to: (1) develop fundamental knowledge and determine the processes controlling the release, mobility, persistence, and possible pathways of contaminants in karst groundwater systems, and (2) characterize transport processes in conduit and diffusion-dominated flow under base flow and storm flow conditions. The work presented herein focuses on the development of geo-hydro statistical tools to characterize flow and transport processes under different flow regimes. Multidimensional, laboratory-scale Geo-Hydrobed models were developed and tested for this purpose. The models consist of stainless-steel tanks containing karstified limestone blocks collected from the karst aquifer formation of northern Puerto Rico. The models a network of sampling wells to monitor flow, pressure, and solute concentrations temporally and spatially. Experimental work entailed making a series of point injections in wells while monitoring the hydraulic response in other wells. Statistical mixed models were applied to spatial probabilities of hydraulic response and weighted injected volume data, and were used to determinate the best spatial correlation structure to represent paths of preferential flow in the limestone units under different groundwater flow regimes. Preliminary testing of the karstified models show that the system can be used to represent the variable transport regime characterized by conduit and diffuses flow in the karst systems. Initial hydraulic characterization indicates a highly heterogeneous system resulting in large preferential flow components. Future works involve characterization of dual porosity system using conservative tracers, fate and transport experiments using phthalates and chlorinated solvents, geo-temporal statistical modeling, and the testing of "green" remediation technologies in karst groundwater. This work is supported by the U.S. Department of Energy, Savannah River (Grant Award No. DE-FG09-07SR22571), and the National Institute of Environmental Health Sciences (NIEHS, Grant Award No. P42ES017198).

Anaya, A. A.; Padilla, I. Y.; Macchiavelli, R. E.

2011-12-01

283

Numerical Analysis of the Molten Steel Flow Consider Solidification at the Continuous Casting Process  

International Nuclear Information System (INIS)

Continuous casting process is widely used for making mid stage of manufactured steel product. Characteristics of steel flow in the mold is very important for mold design and SEN(Submerged Entry Nozzle) and using CFD analysis, numerical approach to molten steel flow can be very useful in understanding its flow characteristics in the mold and also make us easily understand growing of solidification shell thickness near mold wall. This study was done for predicting solidification shell thickness in the beam blank model for continuous casting of steel, using commercial FVM Cartesian Solver, STREAM V6. For considering turbulent flow, the low Reynolds number ?-? model was used. Solidification of molten steel is calculated through the temperature recovery method. And this solidification model was also applied to benchmark cases for validating with experimental and numerical results of other researchers

284

Hydrodynamic viability of chemical looping processes by means of cold flow model investigation  

International Nuclear Information System (INIS)

Highlights: ? Double loop circulating fluidized bed is proposed for chemical looping processes. ? Overview of the cold flow model (CFM) scaling criteria is provided. ? A full scale CFM was built for hydrodynamics validation and scale-up estimations. ? The CFM was tested resembling design conditions, off-design, reforming, etc. ? The CFM performance is described in terms of solids exchange and pressure. -- Abstract: SINTEF Energy Research and the Norwegian University of Science and Technology – NTNU have proposed a 150 kWth reactor system design aiming at further development of chemical looping processes. It consists of a double loop circulating fluidized bed, meant to be used as a platform to study atmospheric chemical looping combustion configurations, as well as other possible chemical looping processes e.g. gas turbine combustion and reforming. The hydrodynamic viability of the design needs to be tested by means of a cold flow model, operated without chemical reactions. An evaluation of the state of the art within cold flow model testing was done. It led to the choice of building a full scale (i.e. 1:1) cold model of the 150 kWth hot rig design, in order to reduce wall-effects which have considerably larger influence at smaller reactor diameters than on larger ones. The cold flow model was extensively tested and experimental results are presented. The aimed design condition, mirroring a chemical looping combustion process adapted to steam generation, was achieved successfully and in a stable way. The performance of the reactor system was further tested in off-design conditions to define operational guidelines for the hot operation. In addition, attempts were done to resemble other chemical looping processes, getting some understanding of how the reactor system may perform and consequently providing solid hydrodynamic bases to improve the design for those applications. In all cases, stable operational sets were found in order to satisfy the cold flow model hydrodynamic requirements consistently with the actual high temperature processes.

285

The transient flow in a centrifugal pump during the discharge valve rapid opening process  

International Nuclear Information System (INIS)

Research highlights: ? DES is suitable for transient performance simulation of pump. ? Rotor-stator interaction phenomenon in transient process is captured. ? The transient performance deviates from the steady performance obviously. ? The flow acceleration and vortics revolution influence pump's transient performance. - Abstract: During the rapid opening period of the discharge valve in the pump system commonly used in nuclear reactor operation, the flow-rate of the pump increases impulsively. In this paper, we report on experiment and numerical simulations which were implemented to investigate the external transient hydrodynamic performance and the internal flow mechanism of the pump during this transient process. External and internal characteristics under different flow-rates were measured with an experimental system. The simulation for steady conditions was based on detached eddy simulation (DES) and sliding mesh was verified by comparing the simulation with test results. More importantly, the transient characteristics during the valve's rapid opening process were simulated using a similar method. Results show that the Q-H curve deviates from the steady-state value. The external characteristics are further explained by analyzing the relative velocity on the middle stream surfaces S1m and S2m between blades. The pump performance during the valve's rapid opening process is influenced both by the fluid acceleration and instantaneous evolcceleration and instantaneous evolutions of the vortex structure.

286

Functional correlates of optic flow motion processing in Parkinson’s disease  

Directory of Open Access Journals (Sweden)

Full Text Available The visual input created by the relative motion between an individual and the environment, also called optic flow, influences the sense of self-motion, postural orientation, veering of gait, and visuospatial cognition. An optic flow network comprising visual motion areas V6, V3A, and MT+, as well as visuo-vestibular areas including posterior insula vestibular cortex (PIVC and cingulate sulcus visual area (CSv, has been described as uniquely selective for parsing egomotion depth cues in humans. Individuals with Parkinson's disease (PD have known behavioral deficits in optic flow perception and visuospatial cognition compared to age- and education-matched control adults (MC. The present study used functional magnetic resonance imaging to investigate neural correlates related to impaired optic flow perception in PD. We conducted fMRI on 40 non-demented participants (23 PD and 17 MC during passive viewing of simulated optic flow motion and random motion. We hypothesized that compared to the MC group, PD participants would show abnormal neural activity in regions comprising this optic flow network. MC participants showed robust activation across all regions in the optic flow network, consistent with studies in young adults, suggesting intact optic flow perception at the neural level in healthy aging. PD participants showed diminished activity compared to MC particularly within visual motion area MT+ and the visuo-vestibular region CSv. Further, activation in visuo-vestibular region CSv was associated with disease severity. These findings suggest that behavioral reports of impaired optic flow perception and visuospatial performance may be a result of impaired neural processing within visual motion and visuo-vestibular regions in PD.

Deepti Putcha

2014-07-01

287

Effects Of Thermal Exchange On Material Flow During Steel Thixoextrusion Process  

International Nuclear Information System (INIS)

Semisolid processing is an innovative technology for near net-shape production of components, where the metallic alloys are processed in the semisolid state. Taking advantage of the thixotropic behavior of alloys in the semisolid state, significant progress has been made in semisolid processing. However, the consequences of such behavior on the flow during thixoforming are still not completely understood. To explore and better understand the influence of the different parameters on material flow during thixoextrusion process, thixoextrusion experiments were performed using the low carbon steel C38. The billet was partially melted at high solid fraction. Effects of various process parameters including the initial billet temperature, the temperature of die, the punch speed during process and the presence of a Ceraspray layer at the interface of tool and billet were investigated through experiments and simulation. After analyzing the results thus obtained, it was identified that the aforementioned parameters mainly affect thermal exchanges between die and part. The Ceraspray layer not only plays a lubricant role, but also acts as a thermal barrier at the interface of tool and billet. Furthermore, the thermal effects can affect the material flow which is composed of various distinct zones.

288

Transactions on Computational Science IX : Special Issue on Voronoi Diagrams in Science and Engineering  

DEFF Research Database (Denmark)

The 9th issue of the Transactions on Computational Science journal, edited by François Anton, is devoted to the subject of Voronoi diagrams in science and engineering. The 9 papers included in the issue constitute extended versions of selected papers from the International Symposium on Voronoi Diagrams, held in Copenhagen, Denmark, June 23-36, 2009. Topics covered include: divide and conquer construction of Voronoi diagrams; new generalized Voronoi diagrams or properties of existing generalized Voronoi diagrams; and applications of Voronoi diagrams and their duals in graph theory, computer graphics, bioinformatics, and spatial process simulation.

2011-01-01

289

Arc numbers from Gauss diagrams  

OpenAIRE

We characterize planar diagrams which may be divided into n arc embeddings in terms of their chord diagrams, generalizing a result of Taniyama for the case n = 2. Two algorithms are provided, one which finds a minimal arc embedding (in quadradic time in the number of crossings), and one which constructs a minimal subdiagram having same arc number as D.

Hagge, Tobias

2010-01-01

290

Cohomology of diagrams of algebras  

OpenAIRE

We consider cohomology of diagrams of algebras by Beck's approach, using comonads. We then apply this theory to computing the cohomology of $\\Psi$-rings. Our main result is that there is a spectral sequence connecting the cohomology of the diagram of an algebra to the cohomology of the underlying algebra.

Robinson, Michael

2008-01-01

291

Recent results in Ring Diagram analysis  

CERN Document Server

The ring-diagram technique was developed by Frank Hill 25 years ago and developed quickly during the late 1990s. It is nowadays one of the most commonly used techniques in local helioseismology. The method consists in the power spectral analysis of solar acoustic oscillations on small regions (2 to 30 degrees) of the solar surface. The power spectrum resembles a set of trumpets nested inside each other and, for a given frequency, it looks like a ring, hence the technique's name. It provides information on the horizontal flow field and thermodynamic structure in the layers immediately below the photosphere. With data regularly provided by MDI (on board SOHO), GONG+ network and more recently HMI (on SDO), many important results have been achieved. In recently years, these results include estimations of the meridional circulation and its evolution with solar cycle; flows associated with active regions, as well as, flow divergence and vorticity; and thermal structure beneath and around active regions. Much progre...

Rabello-Soares, M Cristina

2013-01-01

292

Recleaning of HEPA filters by reverse flow - evaluation of the underlying processes and the cleaning technique  

International Nuclear Information System (INIS)

HEPA filter operation at high concentrations of fine dusts requires the periodic recleaning of the filter units in their service locations. Due to the low mechanical stress induced during the recleaning process the regenration via low pressure reverse flow is a very suitable technique. Recleanability of HEPA filter had been attained for particle diameter >0,4 ?m at air velocities up to 1 m/s, but filter clogging occurred in case of smaller particles. The recleaning forces are too weak for particles <0,4 ?m. With respect to the low tensile strength of HEPA filter media higher flow velocities are excluded. The analysis of reverse flow recleaning in a single pleat device showed extremly non uniform flow pattern in conventional deep-pleat pack geometries. More uniform flow conditions are attained by changing the pleat geometry. The realisation of high flow velocities at the glas fiber medium inside the filter pack requires shortening of the pleates to some 150 mm and the adaptation of the distance between filter pack and the recleaning device with respect to the nozzle diameter and the width of the filter pleats. (orig.). 44 figs., 36 refs

293

A Control-flow Pattern based Horizontal Business Process Model Transformation Approach  

Directory of Open Access Journals (Sweden)

Full Text Available Due to company mergers and business to business interoperability, there is a need for model transformations in the area of business process modeling to facilitate scenarios like model integration and model synchronization. General model transformation approaches do not consider the special properties of business process models and horizontal transformation scenarios. Since different business process modeling languages use different modeling elements and syntax constraints, a business process may have very different representations in different languages. So in many cases it is not easy to transform business process models correctly only using an element-2-element mapping. In order to solve this problem and improve the correction rate of horizontal business process model transformation, in this work we propose CP-BPMT(Control-flow Pattern based Business Process Model Transformation, a horizontal business process model transformation approach in which the operation granularity has been increased from model elements to model fragments illustrating certain control-flow patterns. CP-BPMT is feasible in practice and it can generate transformation results better than element-based approaches. In order to illustrate CP-BPMT approach, a UML-AD2YAWL case study is conducted.

Huang Wenqing

2013-01-01

294

Effective parameters, effective processes: From porous flow physics to in situ remediation technology  

International Nuclear Information System (INIS)

This paper examines the conceptualization of multiphase flow processes on the macroscale, as needed in field applications. It emphasizes that upscaling from the pore-level will in general not only introduce effective parameters but will also give rise to ''effective processes,'' i.e., the emergence of new physical effects that may not have a microscopic counterpart. ''Phase dispersion'' is discussed as an example of an effective process for the migration and remediation of non-aqueous phase liquid (NAPL) contaminants in heterogeneous media. An approximate space-and-time scaling invariance is derived for gravity-driven liquid flow in unsaturated two-dimensional porous media (fractures). Issues for future experimental and theoretical work are identified

295

A Signal Pre-processing Algorithm Applied for Ultrasonic Flow-Meter  

Directory of Open Access Journals (Sweden)

Full Text Available In order to solve the problem of time difference ultrasonic flow meter’s low accuracy, against the basic characteristics of the sample data, a data-processing algorithm is proposed. First, we use shell sort do a data pre-processing to the samples, then remove the error of the sample space by complex digital filter, and use the error compensation algorithm to get the final sample results. Among them, the complex digital filter is mainly composed by median filtering algorithm, sliding window, Peters algorithm and the weighted average algorithm. This kind of data processing algorithm can effectively filter out the error of the sample space. It can also make a large improvement to the accuracy of ultrasonic flow meter while ensure the stability and real-time.

Rang-ding Wang

2013-09-01

296

Evaluation of alternative flow sheets for upgrade of the Process Waste Treatment Plant  

International Nuclear Information System (INIS)

Improved chemical precipitation and/or ion-exchange (IX) methods are being developed at the Oak Ridge National Laboratory (ORNL) in an effort to reduce waste generation at the Process Waste Treatment Plant (PWTP). A wide variety of screening tests were performed on potential precipitation techniques and IX materials on a laboratory scale. Two of the more promising flow sheets have been tested on pilot and full scales. The data were modeled to determine the operating conditions and waste generation at plant-scale and used to develop potential flow sheets for use at the PWTP. Each flow sheet was evaluated using future-valve economic analysis and performance ratings (where numerical values were assigned to costs, process flexibility and simplicity, stage of development, waste reduction, environmental and occupational safety, post-processing requirements, and final waste form). The results of this study indicated that several potential flow sheets should be considered for further development, and more detailed cost estimates should be made before a final selection is made for upgrade of the PWTP. 19 refs., 52 figs., 22 tabs

297

POWER FLOW ANALYSIS OF A CONTINUOUS PROCESS PLANT: (A CASE STUDY  

Directory of Open Access Journals (Sweden)

Full Text Available For the continuous evaluation of the performance of the power system, power flow solutions are essential for exhibiting suitable control actions in case of requirement. This case study presents analysis of the electrical power system of continuous process plant having its own captive generation along with the provision of the Grid connectivity. The different power system elements are modeled as per the manufacturer’s data sheet. To evaluate the steady state performance, power flow simulations and analysis of the complex power system for various invasive operating conditions are carried out.

SMITA ACHARYA, PRAGATI GUPTA, M.A.MUJAWAR

2013-06-01

298

A Thermodynamic Hypothesis to Reconcile Optimality Principles for Flow Processes in Geosystems  

CERN Document Server

This letter proposes a new thermodynamic hypothesis that states that an open and nonlinear natural system, involving positive feedbacks, tends to minimize its resistance to the flow process through it that is imposed by its environment. It allows for a straightforward reconciliation of the two well-known and seemingly inconsistent optimality principles: the minimization of the energy expenditure rate for a river basin, and the maximization of entropy production in the Earth-atmosphere system. We also demonstrate that the hypothesis is consistent with water flow behavior in saturated and unsaturated porous media.

Liu, Hui-Hai

2013-01-01

299

Automating First-Principles Phase Diagram Calculations  

CERN Document Server

Devising a computational tool that assesses the thermodynamic stability of materials is among the most important steps required to build a ``virtual laboratory'', where materials could be designed from first-principles without relying on experimental input. Although the formalism that allows the calculation of solid state phase diagrams from first principles is well established, its practical implementation remains a tedious process. The development of a fully automated algorithm to perform such calculations serves two purposes. First, it will make this powerful tool available to large number of researchers. Second, it frees the calculation process from arbitrary parameters, guaranteeing that the results obtained are truly derived from the underlying first-principles calculations. The proposed algorithm formalizes the most difficult step of phase diagram calculations, namely the determination of the ``cluster expansion'', which is a compact representation of the configurational dependence of the alloy's energ...

De van Walle, A

2002-01-01

300

A new approach of a limiting process for multi-dimensional flows  

Science.gov (United States)

An enhanced Multi-dimensional Limiting Process (e-MLP) is developed for the accurate and efficient computation of multi-dimensional flows based on the Multi-dimensional Limiting Process (MLP). The new limiting process includes a distinguishing step and an enhanced multi-dimensional limiting process. First, the distinguishing step, which is independent of high order interpolation and flux evaluation, is newly introduced. It performs a multi-dimensional search of a discontinuity. The entire computational domain is then divided into continuous, linear discontinuous and nonlinear discontinuous regions. Second, limiting functions are appropriately switched according to the type of each region; in a continuous region, there are no limiting processes and only higher order accurate interpolation is performed. In linear discontinuous and nonlinear discontinuous regions, TVD criterion and MLP limiter are respectively used to remove oscillation. Hence, e-MLP has a number of advantages, as it incorporates useful features of MLP limiter such as multi-dimensional monotonicity and straightforward extensionality to higher order interpolation. It is applicable to local extrema and prevents excessive damping in a linear discontinuous region through application of appropriate limiting criteria. It is efficient because a limiting function is applied only to a discontinuous region. In addition, it is robust against shock instability due to the strict distinction of the computational domain and the use of regional information in a flux scheme as well as a high order interpolation scheme. This new limiting process was applied to numerous test cases including one-dimensional shock/sine wave interaction problem, oblique stationary contact discontinuity, isentropic vortex flow, high speed flow in a blunt body, planar shock/density bubble interaction, shock wave/vortex interaction and, particularly, magnetohydrodynamic (MHD) cloud-shock interaction problems. Through these tests, it was verified that e-MLP substantially enhances the accuracy and efficiency with both continuous and discontinuous multi-dimensional flows.

Kang, Hyung-Min; Kim, Kyu Hong; Lee, Dong-Ho

2010-09-01

301

Phase diagram determinations in Y(x) Nd(1-x) Ba(2) Cu(3) O(y) systems via novel containerless processing techniques  

Science.gov (United States)

Containerless melt processing experiments have been performed on the copper oxide superconductors YBasb2Cusb3Osb{7-delta}, NdBasb2Cusb3Osb{x}, and several partial substitutions of Nd for Y utilizing aero-acoustic levitation and drop tube processing. Aero-acoustic levitation experiments were performed in air on the YBasb2Cusb3Osb{7-delta} compound. In these experiments, the liquidus at this composition and the solidification velocity of the peritectic transformation Ysb2BaCuOsb5\\ + liquid ->\\ YBasb2Cusb3Osb{7-delta} were determined. Drop tube experiments were performed in 20%Osb2-He on YBasb2Cusb3Osb{7-delta} at 1650, 1720, and 1750sp°C and in oxygen on YBasb2Cusb3Osb{7-delta}, Ysb{.9}Ndsb{.l}Basb2Cusb3Osb{x}, Ysb{.8}Ndsb{.2}Basb2Cusb3Osb{x}, Ysb{.7}Ndsb{.3}Basb2Cusb3Osb{x}, Ysb{.5}Ndsb{.5}Basb2Cusb3Osb{x}, Ysb{.3}Ndsb{.7}Basb2Cusb3Osb{x}, Ysb{.1}Ndsb{.9}Basb2Cusb3Osb{x}, and NdBasb2Cusb3Osb{x} at temperatures of 1400-1800sp°C. In oxygen experiments, the liquidus was determined between pure YBasb2Cusb3Osb{7-delta} and NdBasb2Cusb3Osb{x} and determinations of the range of solid solution of the REBasb2Cusb3Osb{x} were attempted at several compositions.

Olive, James Randall

302

A radionuclide tracer method to investigate flow distributions in technical electrolytic systems  

International Nuclear Information System (INIS)

A sampling method using dipping probes is described. It renders possible the performance of multiple measurements in radionuclide tracer investigations of technical systems, yielding flow distribution diagrams. Experimental results of flow distribution measurments in electrolytic copper refining processes are presented. (author)

303

Anomaly diagram contribution in ?- lepton decay  

International Nuclear Information System (INIS)

The branching ratio of the ?- ? ??- ?? decay channel according to the obtained expression of weak hadron currents between pseudoscalar and vector meson states is equal to zero. This channel can be realized via effects of secondary importance, for example, via anomaly diagrams. Using Lagrangian we have defined the acquired matrix element of this process. Further the obtained partial width for the ?- ? ??-?? decay channel is discussed and compared with the available theoretical and experimental data. (A.A.D.)

304

Upscaling of two-phase flow processes in CO2 geological storage  

Science.gov (United States)

Only few current multiphase flow and reactive transport models take into account the impact of heterogeneity on front spreading and mass transfer between high and low permeability zones of the heterogeneous medium and the impact of physical heterogeneity and chemical heterogeneity on chemical reactions rates. Effective equations are available for single-phase conservative and reactive transport and under development for multiphase flow. In the present work, we aim specifically at the upscaling of the two-phase flow dynamics related to processes of CO2 geological storage. The impact of heterogeneity on the two-phase flow dynamics can be quantified in the framework of a multi-continuum approach. This approach allows for the quantification of mass exchange between mobile (background material) and immobile (inclusions) zones of the medium. In this way it accounts systematically for local scale non-equilibrium and thus for the complex flow dynamics in highly heterogeneous and fractured media. The mass exchange between mobile and immobile zones is taken into account by a Multi-Rate Mass Transfer (MRMT) model. Effective equations were formulated in order to describe the impact of spatial heterogeneity on the large-scale two-phase flow behavior. The model was implemented into a MatLab code. Heterogeneity in the hydraulic conductivity of the storage aquifer was accounted through a Gaussian random field. Numerical simulations of 2D two-phase flow through this heterogeneous media were run to obtain the evolution of the actual CO2-rich phase saturation distribution. An equivalent effective model of 1D two-phase flow in homogenous media with MRMT was used to describe the 2D heterogeneous results. The numerical simulations show that a simple 1D homogeneous model with MRMT, capillarity at mobile-immobile interface and in the mobile zone is able to describe two-phase flow in heterogeneous media. However, gravity and macrodispersion terms still have to be included. Extension to heterogeneous multiphase flow is straightforward. The present methodology could contribute significantly to the quantification of the heterogeneity-induced uncertainty of the predicted large-scale multiphase flow and transport behavior in CO2 geological storage.

Silva, O.; Neuweiler, I.; Dentz, M.; Saaltink, M.; Carrera, J.

2012-04-01

305

GDS-based Mask Data Preparation Flow: Data Volume Containment by Hierarchical Data Processing  

Science.gov (United States)

As the industry enters the development of the 65nm node the pressure on the data path and tapeout flow is growing. Design complexity and increased deployment of resolution enhancement techniques (RET) result in rapidly growing file sizes, which turns what used to be the relatively simple task of mask data preparation into a real bottleneck. This discussion introduces the data preparation scheme in the mask house and analyzes its evolution. Mask data preparation (MDP) has evolved from a flow that only needed to support a single mask lithography tool data format (MEBES) with minimal data alteration steps to one which requires the support of many mask lithography tool data formats and at the same time requires significant data alteration to support the increased precision necessary for today"s advanced masks.. However, the MDP flow developed around the MEBES format and it"s derivatives still exists. The design community has migrated towards the use of hierarchical data formats and processes to control file size and processing time. MDP, which from a file size and process complexity point of view is beginning to look more and more like the advanced RET operations performed on the data prior to mask manufacturing, is still standardized on a flat data format that is poorly optimized for a growing number of mask lithography tools. Based on examples it will be shown how this complicates the data handling further. An alternate data preparation flow accommodating the larger files and re-gaining flexibility for turnaround time (TAT) and throughput management is suggested. This flow utilizes the hierarchical GDS-II format as the exchange format for mask data preparation. It complements the existing flow for the most complex designs. The introduction of a hierarchical exchange format enables the transfer of a number of necessary data preparation steps into the hierarchical domain. Data processing strategies are discussed. The paper illustrates the benefit of hierarchical processing based on GDS-II files with experimental data on file size reduction and TAT improvement for direct format conversions vs. re-fracturing as well as other processing steps. The implications for the established data preparation approaches and potential alternatives for the communication between the mask manufacturer and the customer will be discussed. The potential for further enhancements by converting to a hierarchical format that has a more efficient data representation than the commonly used GDS-II format will be discussed and illustrated.

Schulze, Steffen F.; LaCour, Pat; Buck, Peter D.

2002-12-01

306

Signal processing and statistical descriptive reanalysis of steady state chute-flow experiments  

Science.gov (United States)

An accurate knowledge of snow rheology is needed for the mitigation against avalanche hazard. Indeed snow avalanches have a significant impact on the livelihoods and economies of alpine communities. To do so, 60 small-scale in-situ flow experiments were performed with various slopes, temperatures and flow depths. The investigation of these data previously seemed to show the dense flow of dry snow may be composed of two layers; a sheared basal layer made of single snow grains and a less sheared upper layer made of large aggregates. These outcomes were mainly based on the mean velocity profile of the flow and on interpretation in terms of rheological behavior of granular materials and snow microstructure [Pierre G. Rognon et al., 2007]. Here, the main objective remains the same, but the rheological and physical viewpoints are put aside to extract as much information contained in the data as possible various using signal processing methods and descriptive statistics methods as the maximum overlap discrete wavelet transform (MODWT), transfer entropy (TE) and maximum cross-correlation (MCC). Specifically, we aim at the improving the velocity estimations as function of the depth particularly the velocity fluctuations around the mean profile to better document the behavior of dense dry snow flows during a steady and uniform chute regime. The data are composed of pairs of voltage signals (right and left), which makes that the velocity is known indirectly only. The MCC method is classically used to determine the time lag between both signals. Previously, the MCC method that showed the mean velocity profile may be fitted by a simple bilinear function [Pierre G. Rognon et al., 2007], but no interesting temporal dynamics could be highlighted. Hence, a new process method was developed to provide velocity series with much better temporal resolution. The process is mainly made of a MODWT-based denoising method and the choice of window size for correlation. The results prove to be good enough in term of reasonable variability and measurement numbers. A statistical descriptive analysis of the velocity results shows a disagreement with the previous outcomes. Indeed, the clustering method and the empirical probability distribution functions show that the vertical velocity profile may reflect three different behaviors, possibly corresponding to three layers and/or to transient flow layers. These flow layers are located at different heights depending on initial conditions of flow experiments (temperature, slope and depth). Keywords: Maximum cross correlation, MODWT, probability distribution function

truong, hoan; eckert, nicolas; keylock, chris; naaim, mohamed; bellot, hervé

2014-05-01

307

The Mathematical Model of the Coal Gasification Process in a Flow  

Directory of Open Access Journals (Sweden)

Full Text Available The work purpose - perfection of gasification technologies of processing low reactive high zole coals. For purpose achievement the method of an intensification of process of gasification of coal in an ascending stream of the oxidizer activated by nanocatalyst, and also a mathematical model of the specified process is offered. A mathematical model of a process of coal gasification in a one-dimensional steady flow in the form of a system of ordinary differential equations of energy and changes in the concentrations of the reactants is represented in this paper. Model is based on the kinetics of chemical reactions that determine the process. The offered mathematical model will allow to make calculations of parameters of macrokinetics and heat exchange at coal gasification in an ascending stream.

Nikolai Nikolaevich Efimov

2014-11-01

308

Research on fracture analysis, groundwater flow and sorption processes in fractured rocks  

Energy Technology Data Exchange (ETDEWEB)

Due to increasing demand for numerous industrial facilities including nuclear power plants and waste repositories, the feasibility of rocks masses as sites for the facilities has been a geological issue of concern. Rock masses, in general, comprises systems of fractures which can provide pathways for groundwater flow and may also affect the stability of engineered structures. such properties of fractures stimulate a synthetic study on (1) analyses of fracture systems, and (2) characterization of groundwater flow and sorption processes in fractured rocks to establish a preliminary model for assessing suitable sites for industrial facilities. The analyses of fracture systems cover (1) reconstruction of the Cenozoic tectonic movements and estimation of frequency indices for the Holocene tectonic movements, (2) determination of distributions and block movements of the Quaternary marine terraces, (3) investigation of lithologic and geotechnical nature of study area, and (4) examination of the Cenozoic volcanic activities and determination of age of the dike swarms. Using data obtained from above mentioned analyses along with data related to earthquakes and active faults, probabilistic approach is performed to determine various potential hazards which may result from the Quaternary or the Holocene tectonic movements. In addition, stepwise and careful integration of various data obtained from field works and laboratory experiments are carried out to analyze groundwater flow in fractures rocks as follows; (1) investigation of geological feature of the site, (2) identification and characterization of fracture systems using core and televiewer logs, (3) determination of conductive fractures using electrical conductivity, temperature, and flow logs, (4) identification of hydraulic connections between fractures using televiewer logs with tracer tests within specific zones. The results obtained from these processes allow a qualitative interpretation of groundwater flow patterns in the study area. Column experiments of some reactive radionuclides are also performed to examine sorption processes of the radionuclides including retardation coefficients. (author). 118 refs., 18 tabs., 35 figs.

Lee, Dae Ha [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

309

Research on fracture analysis, groundwater flow and sorption processes in fractured rocks  

Energy Technology Data Exchange (ETDEWEB)

Due to increasing demand for numerous industrial facilities including nuclear power plants and waste repositories, the feasibility of rocks masses as sites for the facilities has been a geological issue of concern. Rock masses, in general, comprises systems of fractures which can provide pathways for groundwater flow and may also affect the stability of engineered structures. For the study of groundwater flow and sorption processes in fractured rocks, five boreholes were drilled. A stepwise and careful integration of various data obtained from field works and laboratory experiments were carried out to analyze groundwater flow in fractured rocks as follows; (1) investigation of geological feature of the site, (2) identification and characterization of fracture systems using core and televiewer logs, (3) determination of hydrogeological properties of fractured aquifers using geophysical borehole logging, pumping and slug tests, and continuous monitoring of groundwater level and quality, (4) evaluation of groundwater flow patterns using fluid flow modeling. The results obtained from these processes allow a qualitative interpretation of fractured aquifers in the study area. Column experiments of some reactive radionuclides were also performed to examine sorption processes of the radionuclides including retardation coefficients. In addition, analyses of fracture systems covered (1) reconstruction of the Cenozoic tectonic movements and estimation of frequency indices for the Holocene tectonic movements, (2) determination of distributions and block movements of the Quaternary marine terraces, (3) investigation of lithologic and geotechnical nature of study area, and (4) examination of the Cenozoic volcanic activities and determination of age of the dike swarms. Using data obtained from above mentioned analyses along with data related to earthquakes and active faults, probabilistic approach was performed to determine various potential hazards which may result from the Quaternary or the Holocene tectonic movements. (author). 223 refs., 55 tabs., 144 figs.

Lee, Dae-Ha; Kim, Won-Young; Lee, Seung-Gu [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

1999-12-01

310

Numerical simulations of the laminar-turbulent transition process in plane Poiseuille flow  

International Nuclear Information System (INIS)

Laminar-turbulent transition in plane Poiseuille flow is simulated by numerical integration of the time-dependent three-dimensional Navier-Stokes equations for incompressible flow. The mathematical model of a spatially periodic, timewise developing flow in a moving frame of reference is used to match vibrating-ribbon experiments of Nishioka et al. The numerical discretisation is based on a spectral method with Fourier and Chebyshev polynomial expansions in space and second order finite differences in time. The pressure is calculated using a new method which enforces incompressibility and boundary conditions exactly. This is achieved by deriving the correct boundary conditions for the pressure Poisson equation. The numerical results obtained for two-dimensional finite amplitude disturbances are consistent with nonlinear stability theory. The time-periodic secondary flow is attained by the time-dependent calculation with reasonable accuracy after a long quasi-steady state. No sign of two-dimensional instability, but strong three-dimensional instability as well of the periodic secondary flow as of the quasi-steady state is found. This secondary three-dimensional instability is shown to be responsible for transition. It is shown that the three-dimensional simulations presented here reproduce the experimentally observed transition process up to the spike stage. Detailed comparisons with measurements of mean velocity, rms-values of fluctuation and instantaneous velocity distribution reveal very satisfactory agreement. The formation of peak-valley structure, longitudinal vortices, local high-shear layers and distinct spike-type signals is shown. In addition, the three-dimensional flow field structure before breakdown is investigated. An array of horseshoe vortices similar to those inferred from boundary layer flow visualization experiments is found. Spike signals are produced by local accumulations of low-speed fluid in the downstream loops of these vortices. (orig.)

311

A numerical investigation of the resin flow front tracking applied to the RTM process  

Directory of Open Access Journals (Sweden)

Full Text Available Resin Transfer Molding (RTM is largely used for the manufacturing of high-quality composite components and the key stage during processing is the resin infiltration. The complete understanding of this phenomenon is of utmost importance for efficient mold construction and the fast production of high quality components. This paper investigates the resin flow phenomenon within the mold. A computational application was developed to track the resin flow-front position, which uses a finite volume method to determine the pressure field and a FAN (Flow Analysis Network technique to track the flow front. The mass conservation problem observed with traditional FE-CV (Finite Element-Control Volume methods is also investigated and the use of a finite volume method to minimize this inconsistency is proposed. Three proposed case studies are used to validate the methodology by direct comparison with analytical and a commercial software solutions. The results show that the proposed methodology is highly efficient to determine the resin flow front, showing an improvement regarding mass conservation across volumes.

Jeferson Avila Souza

2011-09-01

312

A numerical investigation of the resin flow front tracking applied to the RTM process  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Resin Transfer Molding (RTM) is largely used for the manufacturing of high-quality composite components and the key stage during processing is the resin infiltration. The complete understanding of this phenomenon is of utmost importance for efficient mold construction and the fast production of high [...] quality components. This paper investigates the resin flow phenomenon within the mold. A computational application was developed to track the resin flow-front position, which uses a finite volume method to determine the pressure field and a FAN (Flow Analysis Network) technique to track the flow front. The mass conservation problem observed with traditional FE-CV (Finite Element-Control Volume) methods is also investigated and the use of a finite volume method to minimize this inconsistency is proposed. Three proposed case studies are used to validate the methodology by direct comparison with analytical and a commercial software solutions. The results show that the proposed methodology is highly efficient to determine the resin flow front, showing an improvement regarding mass conservation across volumes.

Jeferson Avila, Souza; Luiz Alberto Oliveira, Rocha; Sandro Campos, Amico; José Viriato Coelho, Vargas.

2011-09-01

313

Large Eddy Simulation of Transient Flow, Solidification, and Particle Transport Processes in Continuous-Casting Mold  

Science.gov (United States)

The current study developed a coupled computational model to simulate the transient fluid flow, solidification, and particle transport processes in a slab continuous-casting mold. Transient flow of molten steel in the mold is calculated using the large eddy simulation. An enthalpy-porosity approach is used for the analysis of solidification processes. The transport of bubble and non-metallic inclusion inside the liquid pool is calculated using the Lagrangian approach based on the transient flow field. A criterion of particle entrapment in the solidified shell is developed using the user-defined functions of FLUENT software (ANSYS, Inc., Canonsburg, PA). The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern inside the liquid pool exhibits quite satisfactory agreement with the corresponding measurements. The predicted complex instantaneous velocity field is composed of various small recirculation zones and multiple vortices. The transport of particles inside the liquid pool and the entrapment of particles in the solidified shell are not symmetric. The Magnus force can reduce the entrapment ratio of particles in the solidified shell, especially for smaller particles, but the effect is not obvious. The Marangoni force can play an important role in controlling the motion of particles, which increases the entrapment ratio of particles in the solidified shell obviously.

Liu, Zhongqiu; Li, Linmin; Li, Baokuan; Jiang, Maofa

2014-07-01

314

Modifications to the Conduit Flow Process Mode 2 for MODFLOW-2005  

Science.gov (United States)

As a result of rock dissolution processes, karst aquifers exhibit highly conductive features such as caves and conduits. Within these structures, groundwater flow can become turbulent and therefore be described by nonlinear gradient functions. Some numerical groundwater flow models explicitly account for pipe hydraulics by coupling the continuum model with a pipe network that represents the conduit system. In contrast, the Conduit Flow Process Mode 2 (CFPM2) for MODFLOW-2005 approximates turbulent flow by reducing the hydraulic conductivity within the existing linear head gradient of the MODFLOW continuum model. This approach reduces the practical as well as numerical efforts for simulating turbulence. The original formulation was for large pore aquifers where the onset of turbulence is at low Reynolds numbers (1 to 100) and not for conduits or pipes. In addition, the existing code requires multiple time steps for convergence due to iterative adjustment of the hydraulic conductivity. Modifications to the existing CFPM2 were made by implementing a generalized power function with a user-defined exponent. This allows for matching turbulence in porous media or pipes and eliminates the time steps required for iterative adjustment of hydraulic conductivity. The modified CFPM2 successfully replicated simple benchmark test problems. ?? 2011 The Author(s). Ground Water ?? 2011, National Ground Water Association.

Reimann, T.; Birk, S.; Rehrl, C.; Shoemaker, W.B.

2012-01-01

315

Water-droplet cooling process in a steam-turbine bypass flow  

Energy Technology Data Exchange (ETDEWEB)

In industrial power plant operations the performance of a co-generator is equally important to that of a main gas turbine system. Controlling steam temperature in a bypass pipe system needs to be carefully performed by a cooling system in a steam turbine co-generator in order to enhance the system efficiency and life. This paper presents a study of the numerical simulations of a steam flow and heat transfer behavior when subjected to a cooling water spray in the pipe downstream from a high-pressure turbine bypass valve. The structure of a cooling water spray injected into a steam flow was studied for the purpose of developing a physical model to investigate the dissipation and evaporation processes of the cooling water droplets in a high temperature, high turbulent steam flow passage. Heat transfer rates were calculated for a better understanding of the temperature variations in the entire system. A dispersed two-phase model was incorporated for the particle tracking of the droplets injected into the steam flow and the water evaporation process was observed. Further, this study was continued by installing a perforated plate in the pipe section downstream from the water cooling injections. The results of the calculations are quite reasonable, and show a physically sound state.

Amano, R.S.; Draxler, G.R.; Golembiewski, J.M. [Univ. of Wisconsin, Milwaukee, WI (United States). Dept. of Mechanical Engineering

1996-12-31

316

Modifications to the Conduit Flow Process Mode 2 for MODFLOW-2005.  

Science.gov (United States)

As a result of rock dissolution processes, karst aquifers exhibit highly conductive features such as caves and conduits. Within these structures, groundwater flow can become turbulent and therefore be described by nonlinear gradient functions. Some numerical groundwater flow models explicitly account for pipe hydraulics by coupling the continuum model with a pipe network that represents the conduit system. In contrast, the Conduit Flow Process Mode 2 (CFPM2) for MODFLOW-2005 approximates turbulent flow by reducing the hydraulic conductivity within the existing linear head gradient of the MODFLOW continuum model. This approach reduces the practical as well as numerical efforts for simulating turbulence. The original formulation was for large pore aquifers where the onset of turbulence is at low Reynolds numbers (1 to 100) and not for conduits or pipes. In addition, the existing code requires multiple time steps for convergence due to iterative adjustment of the hydraulic conductivity. Modifications to the existing CFPM2 were made by implementing a generalized power function with a user-defined exponent. This allows for matching turbulence in porous media or pipes and eliminates the time steps required for iterative adjustment of hydraulic conductivity. The modified CFPM2 successfully replicated simple benchmark test problems. PMID:21371024

Reimann, Thomas; Birk, Steffen; Rehrl, Christoph; Shoemaker, W Barclay

2012-01-01

317

Batch-processed carbon nanotube wall as pressure and flow sensor  

Science.gov (United States)

A pressure and flow sensor based on the electrothermal-thermistor effect of a batch-processed carbon nanotube wall (CNT wall) is presented. The negative temperature coefficient of resistance (TCR) of CNTs and the temperature dependent tunneling rate through the CNT/silicon junction enable vacuum pressure and flow velocity sensing because the heat transfer rate between CNTs and the surrounding gas molecules differs depending on pressure and flow rate. The CNT walls are synthesized by thermal chemical vapor deposition (CVD) on an array of microelectrodes fabricated on a silicon-on-insulator (SOI) wafer. The CNTs are self-assembled between the microelectrodes and substrate across the thickness of a buried oxide layer during the synthesis process, and the simple batch fabrication results in high throughput and yield. A wide pressure range, down to 3 × 10 - 3 from 105 Pa, and a nitrogen flow velocity range between 1 and 52.4 mm s - 1, are sensed. Further experimental characterizations of the bias voltage dependent response of the sensor as a vacuum pressure gauge are presented.

Choi, Jungwook; Kim, Jongbaeg

2010-03-01

318

Batch-processed carbon nanotube wall as pressure and flow sensor  

International Nuclear Information System (INIS)

A pressure and flow sensor based on the electrothermal-thermistor effect of a batch-processed carbon nanotube wall (CNT wall) is presented. The negative temperature coefficient of resistance (TCR) of CNTs and the temperature dependent tunneling rate through the CNT/silicon junction enable vacuum pressure and flow velocity sensing because the heat transfer rate between CNTs and the surrounding gas molecules differs depending on pressure and flow rate. The CNT walls are synthesized by thermal chemical vapor deposition (CVD) on an array of microelectrodes fabricated on a silicon-on-insulator (SOI) wafer. The CNTs are self-assembled between the microelectrodes and substrate across the thickness of a buried oxide layer during the synthesis process, and the simple batch fabrication results in high throughput and yield. A wide pressure range, down to 3 x 10-3 from 105 Pa, and a nitrogen flow velocity range between 1 and 52.4 mm s-1, are sensed. Further experimental characterizations of the bias voltage dependent response of the sensor as a vacuum pressure gauge are presented.

319

Toward a Grid Work flow Formal Composition  

Energy Technology Data Exchange (ETDEWEB)

This paper exposes a new approach for the composition of grid work flow models. This approach proposes an abstract syntax for the UML Activity Diagrams (UML-AD) and a formal foundation for grid work flow composition in form of a work flow algebra based on UML-AD. This composition fulfils the need for collaborative model development particularly the specification and the reduction of the complexity of grid work flow model verification. This complexity has arisen with the increase in scale of grid work flow applications such as science and e-business applications since large amounts of computational resources are required and multiple parties could be involved in the development process and in the use of grid work flows. Furthermore, the proposed algebra allows the definition of work flow views which are useful to limit the access to predefined users in order to ensure the security of grid work flow applications. (Author)

Hlaoui, Y. B.; BenAyed, L. J.

2007-07-01

320

Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes; SEMIANNUAL  

International Nuclear Information System (INIS)

The emphasis of this work was on investigating the mechanisms and factors that control the recovery of heavy oil with the objective to improve recovery efficiencies. For this purpose the interaction of flow transport and reaction at various scales from the pore network to the field scales were studied. Particular mechanisms to be investigated included the onset of gas flow in foamy oil production and in in-situ steam drive, gravity drainage in steam processes, the development of sustained combustion fronts and the propagation of foams in porous media. Analytical, computational and experimental methods were utilized to advance the state of the art in heavy oil recovery. Successful completion of this research was expected to lead to improvements in the Recovery efficiency of various heavy oil processes

321

Three-dimensional particle tracking velocimetry measurement for bubbly flow with digital color image processing  

International Nuclear Information System (INIS)

In this paper we present the study on a three-dimensional PTV (particle tracking velocimetry) measurement of bubbly flow with color digital image processing. The tracers for the liquid motions shine with yellow-green by an ultra-violet illumination. The bubbles are shadow of the incandescent lights with red-colored cellophane sheets. By using six mirrors we lead the image of the test section seen from different three directions to a high-speed color video camera. Color digital image processing makes the bubbles and tracers extracted from background light. We calculate the velocity vectors, trajectories and the three-dimensional characteristics of the bubbles. We reconstruct the whole bubbly flow and present one by OpenGL. (author)

322

Nonabelian Cut Diagrams and their Applications  

OpenAIRE

A new kind of cut diagram is introduced to sum Feynman diagrams with nonabelian vertices. Unlike the Cutkosky diagrams which compute the discontinuity of single Feynman diagrams, the nonabelian cut diagrams represent a resummation of both the real and the imaginary parts of Feynman diagrams related by permutations. Several applications of the technique are reported, including a resolution of the apparent inconsistency of the baryon problem in large-$N_c$ QCD, a simplified ca...

Lam, C. S.

1996-01-01

323

Numerical simulation of powder volume fraction variation during powder injection molding filling flow process  

OpenAIRE

The variation of powder volume fraction during powder injection molding filling flow process was simulated based on the two-fluid model. The region in which the serious separation between powders and binder occurs was visually observed in the three-dimensional distribution graph, and the industrial CT was used to verify the results. The results indicate that the simulating variation of powder volume fraction can be obtained with this method. The serious separation between powders and binder o...

Fang, W.; He, X-b; Zhang, R-j; Zhang, S-z; Qu, X-h

2013-01-01

324

Calibration in process monitoring by using unsegmented continuous-flow systems  

OpenAIRE

An overview is presented of the different aspects of the role of analytical chemistry in process monitoring and control. On-line monitoring is currently the most attractive option in this area, especially with unsegmented-flow techniques. In addition to allowing automation of these systems, the variety of ways in which calibration and recalibration can be performed allows their adaptation to any situation by using extremely simple, home-made manifolds. The most relevant d...

Castro, M. D. Luque; Valca?rcel, M.

1989-01-01

325

Octopaminergic modulation of temporal frequency coding in an identified optic flow-processing interneuron  

Directory of Open Access Journals (Sweden)

Full Text Available Flying generates predictably different patterns of optic flow compared with other locomotor states. A sensorimotor system tuned to rapid responses and a high bandwidth of optic flow would help the animal to avoid wasting energy through imprecise motor action. However, neural processing that covers a higher input bandwidth itself comes at higher energetic costs which would be a poor investment when the animal was not flying. How does the blowfly adjust the dynamic range of its optic flow-processing neurons to the locomotor state? Octopamine (OA is a biogenic amine central to the initiation and maintenance of flight in insects. We used an OA agonist chlordimeform (CDM to simulate the widespread OA release during flight and recorded the effects on the temporal frequency coding of the H2 cell. This cell is a visual interneuron known to be involved in flight stabilization reflexes. The application of CDM resulted in i an increase in the cell's spontaneous activity, expanding the inhibitory signalling range ii an initial response gain to moving gratings (20 – 60 ms post-stimulus that depended on the temporal frequency of the grating and iii a reduction in the rate and magnitude of motion adaptation that was also temporal frequency-dependent. To our knowledge, this is the first demonstration that the application of a neuromodulator can induce velocity-dependent alterations in the gain of a wide-field optic flow-processing neuron. The observed changes in the cell’s response properties resulted in a 33% increase of the cell’s information rate when encoding random changes in temporal frequency of the stimulus. The increased signalling range and more rapid, longer lasting responses employed more spikes to encode each bit, and so consumed a greater amount of energy. It appears that for the fly investing more energy in sensory processing during flight is more efficient than wasting energy on under-performing motor control.

KitD.Longden

2010-11-01

326

Diagrams and Proofs in Analysis  

DEFF Research Database (Denmark)

The article discusses the role of diagrams in mathematical reasoning based on a case study in analysis.   In the presented example certain combinatorial expressions were first found by using diagrams. In the published proofs the pictures are replaced by reasoning about permutation groups. This paper argues that, even though the diagrams are not present in the papers, they still play a role in the formulation of the proofs. It is shown that they play a role in concept formation as well as representations of proofs. In addition we note that `visualizaton' is used in different ways. In the first sense visualization denotes our inner mental pictures, which enables us to see that a certain fact holds, whereas in the other sense, `visualization' denotes a diagram or representation of something.

Carter, Jessica M H Grund

2010-01-01

327

Jerarquización no paramétrica en procesos caracterizados por múltiples indicadores, mediante diagramas de HASSE y conjuntos parcialmente ordenados: Aplicaciones en ingeniería / Non-parametric ranking in multi-indicator processes using HASSE diagrams and partially ordered sets: Enineering applicarions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish El artículo presenta la aplicación de dos enfoques no paramétricos que permiten jerarquizar procesos a partir de los múltiples indicadores que los caracterizan: el diagrama de Hasse y la teoría de conjuntos parcialmente ordenados. Procesos como la evaluación de un conjunto de proyectos de ingeniería [...] , pueden ser caracterizados por diversos atributos o indicadores que miden aspectos técnicos, financieros, sociales y ambientales, entre otros. A diferencia de otras técnicas que buscan determinar una valor agregado de calidad para cada proceso, mediante el uso de información subjetiva, las técnicas no paramétricas no requieren información adicional y permiten realizar un análisis a priori para: a) evaluar si es posible definir una única jerarquía en forma natural; b) si existen jerarquías en determinados subconjuntos de objetos; o c) si es necesario utilizar algún método que permita realizar la jerarquización únicamente mediante la información de la matriz de múltiples indicadores. Las técnicas seleccionadas se ilustran en tres ejemplos relacionados con el área de la ingeniería. Abstract in english This paper presents the application of two non-parametric approaches allowing the ranking of processes characterized by a multi-indicator matrix: the Hasse diagram and the partial order set theory. Processes like the assessment of engineering projects, are described by a set of technical, financial, [...] social and environmental attributes, among others. While parametric techniques try to determine an aggregate value for each process using subjective information, non-parametric approaches do not require additional information allowing an a priori analysis for: a) assessing if it is possible to define a unique natural ranking; b) determining if there are set of objects that could be partially ranked; or c) applying selected techniques for determine a ranking based only in the information provided by a multi-indicator matrix. The selected approaches are illustrated in three examples, related to engineering problems.

Claudio M, Rocco S; Elvis, Hernández.

2013-06-01

328

An experimental study of fluidization behavior using flow visualization and image processing  

International Nuclear Information System (INIS)

A program of experimental study of fluidization of heavy spherical pellets with water using image processing technique has been started in the Nuclear Engineering Department of the Federal University of Rio Grande do Sul. Fluidization for application in nuclear reactors requires very detailed knowledge of its behavior as the reactivity is closely dependent on the porosity of the fluidized bed. A small modular nuclear reactor concept with suspended core is under study. A modified version of the reactor involves the choice of is to make conical the shape of the reactor core to produce a non-fluctuating bed and consequently guarantee the dynamic stability of the reactor. A 5 mm diameter steel ball are fluidized with water in a conical Plexiglass tube. A pump circulate the water in a loop feeding the room temperature water from the tank into the fluidization system and returning it back to the tank. A controllable valve controls the flow velocity. A high velocity digital CCD camera captures the images of the pellets moving in the fluidized tube. At different flow velocities, the individual pellets can be tracked by processing the sequential frames. A DVT digital tape record stores the images and by acquisition through interface board into a microcomputer. A special program process the data later on. Different algorithm of image treatment determines the velocity fields of the pellets. The behavior of the pellets under different flow velocity and porosity are carefully studw velocity and porosity are carefully studied. (author)

329

An experimental study of fluidization behavior using flow visualization and image processing  

International Nuclear Information System (INIS)

A program of experimental study of fluidization of heavy spherical pellets with water using image processing technique has been started in the Nuclear Engineering Department of the Federal University of Rio Grande do Sul. Fluidization for application in nuclear reactors requires very detailed knowledge of its behavior as the reactivity id closely dependent on the porosity of the fluidized bed. A small modular nuclear reactor concept with suspended core is under study. A modified version of the reactor involves the choice of is to make conical the shape of the reactor core to produce a non-fluctuating bed and consequently guarantee the dynamic stability of the reactor. A 5 mm diameter steel ball are fluidized with water in a conical Plexiglass tube. A pump circulate the water in a loop feeding the room temperature water from the tank into the fluidization system and returning it back to the tank. A controllable valve controls the flow velocity. A high velocity digital CCD camera captures the images of the pellets moving in the fluidized tube. At different flow velocities, the individual pellets can be tracked by processing the sequential frames. A DVT digital tape record stores the images and by acquisition through interface board into a microcomputer. A spatial program process the data later on. Different algorithm of image treatment determines the velocity fields of the pellets. The behavior of the pellets under different flow velocity and porosity are carefully studw velocity and porosity are carefully studied. (author)

330

Phase diagrams of the elements  

International Nuclear Information System (INIS)

A summary of the pressure-temperature phase diagrams of the elements is presented, with graphs of the experimentally determined solid-solid phase boundaries and melting curves. Comments, including theoretical discussion, are provided for each diagram. The crystal structure of each solid phase is identified and discussed. This work is aimed at encouraging further experimental and theoretical research on phase transitions in the elements

331

Phase Diagrams for Sonoluminescing Bubbles  

OpenAIRE

Sound driven gas bubbles in water can emit light pulses. This phenomenon is called sonoluminescence (SL). Two different phases of single bubble SL have been proposed: diffusively stable and diffusively unstable SL. We present phase diagrams in the gas concentration vs forcing pressure state space and also in the ambient radius vs gas concentration and vs forcing pressure state spaces. These phase diagrams are based on the thresholds for energy focusing in the bubble and two ...

Hilgenfeldt, Sascha; Lohse, Detlef; Brenner, Michael P.

1996-01-01

332

SINR Diagram with Interference Cancellation  

OpenAIRE

In this paper we study the reception zones of a wireless network in the SINR model with receivers that employ \\emph{interference cancellation} (IC), a technique that allows a receiver to decode interfering signals, and \\emph{cancel} them from the received signal in order to decode its intended message. We first derive some important topological properties of the diagram describing the reception zones and their connections to \\emph{high-order Voronoi diagrams} and other relat...

Avin, Chen; Cohen, Asaf; Haddad, Yoram; Kantor, Erez; Lotker, Zvi; Parter, Merav; Peleg, David

2013-01-01

333

Phase Diagram of Doped Manganates  

CERN Document Server

The phase diagram of doped manganate compounds La_{1-x}A_xMnO_3 (with divalent A) is studied. We analyze an extension of the double exchange model using the Schwinger boson formalism. Earlier work by de Gennes on the existence of a canted phase is reproduced, although this phase is shown to be unstable towards phase separation in a broad regime of physical interest. We numerically solve the model's mean field equations and plot its phase diagram.

Arovas, D P; Arovas, Daniel P.; Guinea, Francisco

1997-01-01

334

Phase Diagrams for Traffics on the Crossroad: II. The Cases of Different Velocities  

Science.gov (United States)

Cell automaton simulations have been performed for the traffic flows on two one-lane roads, crossing at a point, where the maximum velocities of the northbound and the eastbound cars are different. The phase diagrams are constructed, and it has turned out that the phase diagrams consist of six regions. The obtained phase diagrams are interpreted on the basis of the local occupation probability method.

Ishibashi, Yoshihiro; Fukui, Minoru

2001-12-01

335

Reheating Phase Diagram for Higgs Inflation  

CERN Document Server

We investigate the impact on the inflationary predictions from various reheating histories which are characterized by an e-folding number $N_{\\mathrm{reh}}$ and an effective equation-of-state parameter $w_{\\mathrm{reh}}$ during reheating process. For Higgs inflation with a non-minimal coupling to gravity, the predictions are obtained on the $N_{\\mathrm{reh}}\\!\\!-\\!w_{\\mathrm{reh}}$ reheating phase diagram. We find that the predictions are insensitive to reheating phase. Within the $1\\sigma$ region of the scalar spectral index $n_s$ reported by Planck 2014 Preliminary, almost all possible reheating histories are allowed on the reheating phase diagram, where Higgs inflation with canonical reheating history $w_{\\mathrm{reh}}=0$ lies near the upper edge of the $1\\sigma$ range of $n_s$. Future measurements of $n_s$ with high precision will identify the reheating physics of Higgs inflation.

Cai, Rong-Gen; Wang, Shao-Jiang

2015-01-01

336

An adaptive optimisation scheme for controlling air flow process with satisfactory transient performance  

Directory of Open Access Journals (Sweden)

Full Text Available A non-identifier-based adaptive PI controller is designed using a gradient approach to improve the performance of a control system when device aging and environmental factors degrade the efficiency of the process. The design approach is based on the model reference adaptive control technique. The controller drives the difference (error between the process response and desired model output to zero asymptotically at a rate constrained by the desired characteristics of the model. The tuning rules are designed and justified for a non-linear process with dominant dynamics of second order. The advantage of this method for tracking and regulation compared to adaptive MIT control was validated in real time by conducting experiments on a laboratory air flow control system using the dSPACE interface in the SIMULINK software. The experimental results show that the process with adaptive PI controller has better dynamic performance and robustness than that with traditional adaptive MIT controller.

Sivakumar Dakshinamurthy

2010-07-01

337

Analyzing the Makespan using Processing Time Splitting Technique in Permutation Flow Shop Scheduling Problems  

Directory of Open Access Journals (Sweden)

Full Text Available In the shop floor, the production target is always a challenging job for any planning engineer. Meeting the due date is critical for the financial claims and marketing purposes. While scheduling, sometimes two or more operations are combined for processing and considered as a single job. Similarly, one machine may be overloaded with longer processing times. Some may be intentional, whereas, some may be unknowingly done. Clear definition of the processes and the corresponding spans before scheduling the jobs is highly significant for the speedy completion of all the jobs. In this paper, both the situations are analyzed with a numerical example. The effects of splitting the processing times and introducing an additional similar machine in the production line are studied for a permutation flow shop scheduling problem.

Baskar A

2014-11-01

338

The Measurement Of Relative Blood Flow: An Example Of Centralized Radiological Image Processing  

Science.gov (United States)

The ability to perform post-processing on diagnostic images is becomming more and more important especially as an effort to extract additional information to aid diagnosis. However, it is often the case that researchers need to implement their own image analysis which is beyond the ability of manufacturer-supplied software. This analysis can be done by either directly programming the clinical device or performing the analysis on a centralized image processing system. This paper presents an example where advanced image analysis was performed on a centralized system. Digital fluorographic (DF) blood flow analysis was done after DF images were transferred from the Angiographic Laboratory to the Image Processing Laboratory. The advantages and disadvantages of the use of such a centralized processing scheme are discussed in the light of the DF example.

Mankovich, Nicholas J.; Papin, Patrick J.; Chuang, Keh-Shih; Lo, Shih-Chung B.; Huang, H. K.; Hernandez-Armas, Jose

1984-06-01

339

Step bunching process induced by the flow of steps at the sublimated crystal surface  

CERN Document Server

Stepped GaN(0001) surface is studied by the kinetic Monte Carlo method and compared with the model based on Burton-Carbera-Frank equations. Successive stages of surface pattern evolution during high temperature sublimation process are discussed. At low sublimation rates clear, well defined step bunches form. The process happens in the absence or for very low Schwoebel barriers at the ideal surface. Bunches of several steps are well separated, move slowly and are rather stiff. Character of the process changes for more rapid sublimation process where double step formations become dominant and together with meanders and local bunches assemble into the less ordered surface pattern. Solution of the analytic equations written for one dimensional system confirms that step bunching is induced by the particle advection caused by step-flow anisotropy. This anisotropy becomes important when due to the low Schwoebel barrier both sides of step are symmetric. Simulations show that in the opposite limit of very high Schwoeb...

Zaluska-Kotur, M A; Krukowski, S

2012-01-01

340

Coupled modeling of hydrologic and hydrodynamic processes including overland and channel flow  

Science.gov (United States)

A coupling framework between a hydrologic model and a hydrodynamic model has been developed. The resultant coupled model, tRIBS-OFM, considers spatially-distributed, physically-based hydrologic processes over the land-surface and subsurface by using the TIN (Triangulated Irregular Network)-Based Real Time Integrated Basin Simulator (tRIBS); the hydrodynamic component is the overland flow model (OFM), which solves the two-dimensional Saint-Venant (shallow-water) equations using Roe's approximate Riemann solver on an unstructured grid. The original OFM formulation targeted hydraulic applications and did not provide an accurate solution for partially-submerged mesh cells. Modifications of the hydrodynamic model are presented here that affect the calculation of flux, bottom slope, and friction slope terms of the Saint-Venant formulation by applying a new method of reconstruction of variables. The proposed method significantly enhances the accuracy of hydrologic applications by resolving the typical numerical artifacts associated with low precipitation and runoff production rates. Several comparisons with analytical solutions, observed data, and other numerical models have been carried out for different domain geometries and various flow conditions. Two applications to a synthetic domain and a real-world basin, the Peacheater Creek watershed (64 km2) located near Christie, OK, USA, are also presented to demonstrate the scalability of the model's application and its robust performance. Various physically-based metrics of watershed simulation are illustrated, such as the runoff production occurrences and rates, streamflow, flow depth, velocity, etc. The coupled model makes feasible a range of real-world problems that models based on the kinematic or inertia-free approximations cannot simulate accurately. These include microtopographic flow disturbances due to vegetation and obstacles, backwater effects, and converging-diverging flow characteristics. The coupled model thus provides more comprehensive simulation capabilities that are not affected by assumptions regarding the reproduced flow regime.

Kim, Jongho; Warnock, April; Ivanov, Valeriy Y.; Katopodes, Nikolaos D.

2012-03-01

341

Diagrams of real stresses of metallic materials irradiated by neutrons  

International Nuclear Information System (INIS)

True stress-strain diagrams obtained using optico-electronic extensometer (OEE) for certain neutron-irradiated materials with bcc and fcc crystal lattices (steel 12Kh18N10T, commercial molybdenum) are presented. It is shown that true flow stresses of both initial and irradiated materials, determined using the optical-electronic extensometer differ considerably from conditional stresses calculated by standard techniques

342

Overland flow generation processes in sub-humid Mediterranean forest stands  

Science.gov (United States)

Forest soils in north and central Portugal have suffered and continue to suffer major structural changes as a result of forest management techniques, such as clear-felling and as a result of wildfire and rip-ploughing, which is carried out to prepare the ground for planting tree seedlings. In soils that have undergone these changes, the characteristics tend to be different for coniferous plantations, where the root system tends to die when the trees are cut following fire and subsequently may be consumed by fire to form a macropore network, and other types of tree plantations where the root system remains alive and allows regrowth from the sawn tree stumps. Overland flow thresholds decrease sharply as a result of rip-ploughing and forest fires and increase following clear-felling. The time taken for trees to reach maturity after wildfire differs markedly betwen the two main species (Pinus pinaster Aiton and Eucalyptus globulus Labill.) stands. In this paper, overland flow is considered in relation to rainfall, throughfall and throughflow, both in terms of hydrology and hydrochemistry in an attempt to understand overland flow generation mechanisms for a variety of forest land uses (mature pine and eucalyptus, pine seedling regrowth and eucalyptus regrowth from tree stumps, eucalyptus plantations and burned pine). Overland flow generation processes change sharply, even within a single rainfall event, as reflected in the soil hydrological processes and the hydrochemical fingerprints. These effects result from the different contact times for water and soil, which cause differences in the absorption and exhudation processes for the two species

Ferreira, A. J. D.; Ferreira, C. S. S.; Coelho, C. O. A.; Walsh, R. P. D.; Shakesby, R. A.

2012-04-01

343

The penguin diagram and the process ????  

International Nuclear Information System (INIS)

It is pointed out that the ''penguin''-contribution is the only part of the standard ?S=1 weak Hamiltonian which contributes to the decay modes ?-??-? and ?-??-?. These decay modes could therefore potentially be good tests of the coefficients of the ''penguin' operators. Matrix elements of the weak Hamiltonian between baryon states are estimated within a quark model (mainly the bag model). The theoretical predictions for the branching ratios are found to be uncertain. But the analysis indicates that Br(?-??-?) approximately 10-5 to 10-4 and Br(?-??-?) approximately 10-6 to 10-5. (Auth.)

344

Method for coding and documentation of reliability block-diagram  

International Nuclear Information System (INIS)

Reliability block-diagram is a widely used method in risk, availability and reliability analysis. In comparison with the faulttree method it offers many advantages, eg better functional analogy with the analyzed process. This analogy, however, easily disappears if the amount of details to be modelled is large. This paper describes a method, developed during the PRA of TVO 1, which makes it possible to create reliability block-diagrams in a hierarchial way without loosing any essential information

345

On Hardy's paradox, weak measurements, and multitasking diagrams  

International Nuclear Information System (INIS)

We discuss Hardy's paradox and weak measurements by using multitasking diagrams, which are introduced to illustrate the progress of quantum probabilities through the double interferometer system. We explain how Hardy's paradox is avoided and elaborate on the outcome of weak measurements in this context. -- Highlights: ? Hardy's paradox explained and eliminated. ? Weak measurements: what is really measured? ? Multitasking diagrams: introduced and used to discuss quantum mechanical processes.

346

Transient Heat and Material Flow Modeling of Friction Stir Processing of Magnesium Alloy using Threaded Tool  

Energy Technology Data Exchange (ETDEWEB)

A three-dimensional transient computational fluid dynamics (CFD) model was developed to investigate the material flow and heat transfer during friction stir processing (FSP) in an AZ31B magnesium alloy. The material was assumed to be a non-Newtonian viscoplastic fluid, and the Zener-Hollomon parameter was used to describe the dependence of material viscosity on temperature and strain rate. The material constants used in the constitutive equation were determined experimentally from compression tests of the AZ31B Mg alloy under a wide range of strain rates and temperatures. A dynamic mesh method, combining both Lagrangian and Eulerian formulations, was used to capture the material flow induced by the movement of the threaded tool pin. Massless inert particles were embedded in the simulation domain to track the detailed history of material flow. The actual FSP was also carried out on a wrought Mg plate where temperature profiles were recorded by embedding thermocouples. The predicted transient temperature history was found to be consistent with that measured during FSP. Finally, the influence of the thread on the simulated results of thermal history and material flow was studied by comparing two models: one with threaded pin and the other with smooth pin surface.

Yu, Zhenzhen [ORNL; Zhang, Wei [ORNL; Choo, Hahn [ORNL; Feng, Zhili [ORNL

2012-01-01

347

Flow regimes of condensation processes in the emergency condenser test facility. Final report  

International Nuclear Information System (INIS)

Within the framework of research project 15 NU 09485, 'Calculation and configuration of the passive emergency condenser of an innovative, natural-convection BWR (SWR600) using the ATHLET code', which is closely connected with research project 15 NU 9050, 'Emergency condenser for a medium-output BWR - experiments for performance assessment', measurements were carried out at the NOKO experimental facility for identification of flow regimes and condensation processes. The task was to measure the flow regimes in the NOKO tube by means of needle-type conductuivity probes. The probes were placed into a single heat transfer tube (NOKO single tube) specifically installed for this purpose at the NOKO experimental facility. Several probes were inserted in each of two selected flow sections so that the phase distribution could be measured dynamically during liquid level lowering, i.e. at the probes positioned in downward level direction. The shape of the phase boundaries was reconstructed from the measured data. This arrangement of the probes detects and yields measured data of the various flow regimes occurring. (orig./DG)

348

Hydrodynamic analysis of binary immiscible metallurgical flow in a novel mixing process: rheomixing  

Science.gov (United States)

This paper presents a hydrodynamic analysis of binary immiscible metallurgical flow by a numerical simulation of the rheomixing process. The concept of multi-control is proposed for classifying complex processes and identifying individual processes in an immiscible alloy system in order to perform simulations. A brief review of fabrication methods for immiscible alloys is given, and fluid-flow aspects of a novel fabrication method: rheomixing by a twin-screw extruder (TSE), are analysed. Fundamental hydrodynamic micromechanisms in a TSE are simulated by a piecewise-linear volume-of-fluid (VOF) method coupled with the continuum surface force algorithm. This revealed that continuous reorientation in the TSE process could produce fine droplets and the best mixing efficiency. It is verified that a TSE is a better mixing device than a single-screw extruder and can achieve finer droplets. Numerical results show good qualitative agreement with experimental results. It is concluded that rheomixing by a TSE can be successfully employed for casting immiscible engineering alloys due to its unique characteristics of reorientation and surface renewal.

Tang, H.; Wrobel, L. C.; Fan, Z.

2005-08-01

349

Modern approaches to processing large hyperspectral and multispectral aerospace data flows  

Science.gov (United States)

We consider approaches to processing large hyperspectral and multispectral imaging flows produced in aerospace monitoring for solving a wide range of problems of management of natural resources, environmental security, prevention of natural disasters and technogenic accidents, as well as problems of real economy, and basic and applied sciences. We analyze the specific features of the phases of hyperspectral data analysis and describe a software and hardware system that uses new and improved methods and algorithms for processing large flows of hyperspectral and other aerospace data and has a high-performance computer. This system contains different types of software for identifying the types of given objects by solving inverse problems of remote sensing as well as by analyzing their qualitative and quantitative characteristics, combined multiparameter processing of hyperspectral aerospace data, tracking the local changes including those related to changes in meteorological conditions and vegetation periods, detecting and identifying the types of small objects on the basis of analysis of individual parts of the image, detecting and identifying heat sources, etc. We bring examples of processing of hyperspectral and multispectral satellite images with the help of software and hardware tools developed.

Bondur, V. G.

2014-12-01

350

Using digital flow cytometry to assess the degradation of three cyanobacteria species after oxidation processes.  

Science.gov (United States)

Depending on drinking water treatment conditions, oxidation processes may result in the degradation of cyanobacteria cells causing the release of toxic metabolites (microcystin), odorous metabolites (MIB, geosmin), or disinfection byproduct precursors. In this study, a digital flow cytometer (FlowCAM(®)) in combination with chlorophyll-a analysis was used to evaluate the ability of ozone, chlorine, chlorine dioxide, and chloramine to damage or lyse cyanobacteria cells added to Colorado River water. Microcystis aeruginosa (MA), Oscillatoria sp. (OSC) and Lyngbya sp. (LYN) were selected for the study due to their occurrence in surface water supplies, metabolite production, and morphology. Results showed that cell damage was observed without complete lysis or fragmentation of the cell membrane under many of the conditions tested. During ozone and chlorine experiments, the unicellular MA was more susceptible to oxidation than the filamentous OSC and LYN. Rate constants were developed based on the loss of chlorophyll-a and oxidant exposure, which showed the oxidants degraded MA, OSC, and LYN according to the order of ozone > chlorine ~ chlorine dioxide > chloramine. Digital and binary images taken by the digital flow cytometer provided qualitative insight regarding cell damage. When applying this information, drinking water utilities can better understand the risk of cell damage or lysis during oxidation processes. PMID:23726712

Wert, Eric C; Dong, Mei Mei; Rosario-Ortiz, Fernando L

2013-07-01

351

High resolution measurements of mixing and reaction processes in turbulent flows  

Science.gov (United States)

High resolution multi-dimensional imaging measurements were reported of the detailed structure of mixing and combustion processes in turbulent flows. These measurements are unique because they provide the first fully-resolved quantitative data on scalar dissipation rate field structure in turbulent reacting flows. These molecular mixing rate data were coupled with a two-parameter non-equilibrium reaction chemistry formulation to generate instantaneous maps of combustion species concentration and reaction rate fields in turbulent flames under varying degrees of chemical non-equilibrium. Results showed that the reaction zone structure transitioned smoothly from a thin layer-like structure to broad distributed reaction zones as the flame extinction limit was approached. Additionally, fully-resolved four-dimensional spatio-temporal imaging measurements were used to measure the larger scale topology of these scalar dissipation layers. Results showed that the distribution of layer separations is very nearly lognormal. This finding verified a recent analytical model of the multiplicative character of the repeated stretching and folding processes leading to this layer-like structure in the scalar dissipation fields in turbulent flows. This model, coupled with this two-parameter non-equilibrium reaction chemistry formulation, provides a simple approach for predicting the fine structure of molecular mixing and non-equilibrium reaction chemistry in turbulent combustion.

Dahm, Werner J.

1992-11-01

352

Inline chemical process analysis in micro-plants based on thermoelectric flow and impedimetric sensors  

International Nuclear Information System (INIS)

In micro-plants, as used in chemical micro-process engineering, an integrated inline analytics is regarded as an important factor for the development and optimization of chemical processes. Up to now, there is a lack of sensitive, robust and low-priced micro-sensors for monitoring mixing and chemical conversion in micro-fluidic channels. In this paper a novel sensor system combining an impedimetric sensor and a novel pressure stable thermoelectric flow sensor for monitoring chemical reactions in micro-plants is presented. The CMOS-technology-based impedimetric sensor mainly consists of two capacitively coupled interdigital electrodes on a silicon chip. The thermoelectric flow sensor consists of a heater in between two thermopiles on a perforated membrane. The pulsed and constant current feeds of the heater were analyzed. Both sensors enable the analysis of chemical conversion by means of changes in the thermal and electrical properties of the liquid. The homogeneously catalyzed synthesis of n-butyl acetate as a chemical model system was studied. Experimental results revealed that in an overpressure regime, relative changes of less than 1% in terms of thermal and electrical properties can be detected. Furthermore, the transition from one to two liquid phases accompanied by the change in slug flow conditions could be reproducibly detected

353

Identification Method of Fluidized Bed's Gas-solid Two Phase Flow Regime Based on Images Processing and Genetic Neural Network  

Science.gov (United States)

Gas-solid two-phase flow widely exists in modern industry process. Two-phase flow and heat transfer characters are extremely influenced by the flow regimes. Therefore, a flow regime identification method based on images statistical features of gray histogram and genetic neural network is proposed. Gas-solid fluidized bed flow images are captured by a high speed photography system in a self-designed and built fluidized bed device. The images statistical features of the gray histogram are extracted using image processing techniques. Then the images statistical eigenvectors of flow regime are established. The genetic neural network is trained using those eigenvectors as flow regime samples and the flow regime intelligent identification is realized. The test result shows after successful training the genetic neural network not only can effectively identify five typical flow regimes of gas-solid two-phase flow in fluidized bed, but also can solve the convergence problem in the network trains effectively. The whole identification accuracy is 99.72%, opening up a new avenue for the flow pattern recognition.

Zhou, Y. L.; Fan, Z. R.

2010-03-01

354

River flow forecasting with Artificial Neural Networks using satellite observed precipitation pre-processed with flow length and travel time information: case study of the Ganges river basin  

Directory of Open Access Journals (Sweden)

Full Text Available This paper explores the use of flow length and travel time as a pre-processing step for incorporating spatial precipitation information into Artificial Neural Network (ANN models used for river flow forecasting. Spatially distributed precipitation is commonly required when modelling large basins, and it is usually incorporated in distributed physically-based hydrological modelling approaches. However, these modelling approaches are recognised to be quite complex and expensive, especially due to the data collection of multiple inputs and parameters, which vary in space and time. On the other hand, ANN models for flow forecasting are frequently developed only with precipitation and discharge as inputs, usually without taking into consideration the spatial variability of precipitation. Full inclusion of spatially distributed inputs into ANN models still leads to a complex computational process that may not give acceptable results. Therefore, here we present an analysis of the flow length and travel time as a basis for pre-processing remotely sensed (satellite rainfall data. This pre-processed rainfall is used together with local stream flow measurements of previous days as input to ANN models. The case study for this modelling approach is the Ganges river basin. A comparative analysis of multiple ANN models with different hydrological pre-processing is presented. The ANN showed its ability to forecast discharges 3-days ahead with an acceptable accuracy. Within this forecast horizon, the influence of the pre-processed rainfall is marginal, because of dominant influence of strongly auto-correlated discharge inputs. For forecast horizons of 7 to 10 days, the influence of the pre-processed rainfall is noticeable, although the overall model performance deteriorates. The incorporation of remote sensing data of spatially distributed precipitation information as pre-processing step showed to be a promising alternative for the setting-up of ANN models for river flow forecasting.

M. K. Akhtar

2009-04-01

355

River flow forecasting with artificial neural networks using satellite observed precipitation pre-processed with flow length and travel time information: case study of the Ganges river basin  

Directory of Open Access Journals (Sweden)

Full Text Available This paper explores the use of flow length and travel time as a pre-processing step for incorporating spatial precipitation information into Artificial Neural Network (ANN models used for river flow forecasting. Spatially distributed precipitation is commonly required when modelling large basins, and it is usually incorporated in distributed physically-based hydrological modelling approaches. However, these modelling approaches are recognised to be quite complex and expensive, especially due to the data collection of multiple inputs and parameters, which vary in space and time. On the other hand, ANN models for flow forecasting are frequently developed only with precipitation and discharge as inputs, usually without taking into consideration the spatial variability of precipitation. Full inclusion of spatially distributed inputs into ANN models still leads to a complex computational process that may not give acceptable results. Therefore, here we present an analysis of the flow length and travel time as a basis for pre-processing remotely sensed (satellite rainfall data. This pre-processed rainfall is used together with local stream flow measurements of previous days as input to ANN models. The case study for this modelling approach is the Ganges river basin. A comparative analysis of multiple ANN models with different hydrological pre-processing is presented. The ANN showed its ability to forecast discharges 3-days ahead with an acceptable accuracy. Within this forecast horizon, the influence of the pre-processed rainfall is marginal, because of dominant influence of strongly auto-correlated discharge inputs. For forecast horizons of 7 to 10 days, the influence of the pre-processed rainfall is noticeable, although the overall model performance deteriorates. The incorporation of remote sensing data of spatially distributed precipitation information as pre-processing step showed to be a promising alternative for the setting-up of ANN models for river flow forecasting.

M. K. Akhtar

2009-09-01

356

River flow forecasting with artificial neural networks using satellite observed precipitation pre-processed with flow length and travel time information: case study of the Ganges river basin  

Science.gov (United States)

This paper explores the use of flow length and travel time as a pre-processing step for incorporating spatial precipitation information into Artificial Neural Network (ANN) models used for river flow forecasting. Spatially distributed precipitation is commonly required when modelling large basins, and it is usually incorporated in distributed physically-based hydrological modelling approaches. However, these modelling approaches are recognised to be quite complex and expensive, especially due to the data collection of multiple inputs and parameters, which vary in space and time. On the other hand, ANN models for flow forecasting are frequently developed only with precipitation and discharge as inputs, usually without taking into consideration the spatial variability of precipitation. Full inclusion of spatially distributed inputs into ANN models still leads to a complex computational process that may not give acceptable results. Therefore, here we present an analysis of the flow length and travel time as a basis for pre-processing remotely sensed (satellite) rainfall data. This pre-processed rainfall is used together with local stream flow measurements of previous days as input to ANN models. The case study for this modelling approach is the Ganges river basin. A comparative analysis of multiple ANN models with different hydrological pre-processing is presented. The ANN showed its ability to forecast discharges 3-days ahead with an acceptable accuracy. Within this forecast horizon, the influence of the pre-processed rainfall is marginal, because of dominant influence of strongly auto-correlated discharge inputs. For forecast horizons of 7 to 10 days, the influence of the pre-processed rainfall is noticeable, although the overall model performance deteriorates. The incorporation of remote sensing data of spatially distributed precipitation information as pre-processing step showed to be a promising alternative for the setting-up of ANN models for river flow forecasting.

Akhtar, M. K.; Corzo, G. A.; van Andel, S. J.; Jonoski, A.

2009-09-01

357

An Approach to Code Generation from UML Diagrams  

Directory of Open Access Journals (Sweden)

Full Text Available The Unified Modeling Language (UML has now become the de-facto industry standard for object-oriented (OO software development. UML provides a set of diagrams to model structural and behavioral aspects of an object-oriented system. Automatic translation of UML diagrams to object oriented code is highly desirable because it eliminates the chances of introduction of human errors in the translation process. Automatic code generation is efficient which, in turn, helps the software engineers deliver the software on time. However, major challenges in this area include checking consistency of UML models, and ensuring accuracy, maintainability, and efficiency of the generated code. This paper represents an approach to generate efficient and compact executable code from UML diagram. By analyzing the characteristics UML diagram, a coding strategy is proposed, and a structure identification and coding algorithm are put forward for code generation from UML diagram. Based on the coding strategy an algorithm is proposed to generate code from UML diagrams using some intermediate steps. The main objective of this paper is to generate the code from UML diagram.

Harshal D. Gurad

2014-01-01

358

Experimental and theoretical study of flowing foam and of the liquid film formed on the wall for the improvement of decontamination processes using foams  

International Nuclear Information System (INIS)

Amongst chemical decontamination techniques, the foam cleaning process has the advantage of reducing the amount of liquid used, thus limiting the quantity of the chemical reagents and the secondary waste volume. In order to improve this process, it is essential to understand the behaviour of the foam in the vicinity of the contaminated surface. Two methods of study have been initiated. Firstly, the characterization of the liquid film formed on the wall, and secondly, the characterization of the foam bed. Furthermore, our goal is to set up a drainage model which enables a choice of process parameters. Flush-mounted conductance probes have been developed in order to determine the thickness of the liquid film at the surface and the foam liquid fraction. The influence of the foam on the film structure and the interpretation of the thickness measured is discussed. The process studied consists of filling the facility with foam and letting the foam drain once the facility is full. It was demonstrated that the liquid film thickness varies between a few microns and 50 ?m and that the value depends on position and time. Furthermore, a strong correlation links the film thickness and the foam liquid fraction. A drift-flux model has been built to describe the drainage of the upstream flow or static foam. The model is solved by using the method of characteristics. Analytical solutions are obtained and the liquid fraction evolution can easily be represented on a single diagram. The parameters of the void-drift closure law have been deducted from the experiments. The comparison to experimental data has shown that the model is well adapted. The laboratory therefore has experimental and theoretical equipment to study any foam. Finally, the model is applied to realistic decontamination configurations in order to present how determine the parameters of the process. (author)

359

Gas Hydrate Stability and Sampling: The Future as Related to the Phase Diagram  

OpenAIRE

The phase diagram for methane + water is explained, in relation to hydrate applications, such as in flow assurance and in nature. For natural applications, the phase diagram determines the regions for hydrate formation for two- and three-phase conditions. Impacts are presented for sample preparation and recovery. We discuss an international study for “Round Robin” hydrate sample preparation protocols and testing.

Dendy Sloan, E.; Sum, Amadeu K.; Koh, Carolyn A.

2010-01-01

360

Design of Natural Fiber Composites Chemical Container Using Resin Flow Simulation of VARTML Process  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an investigation on mechanical properties of flax natural fiber composite is performed as a precedent study on the design of eco-friendly structure using flax natural fiber composite. The Vacuum Assisted Resin Transfer Molding-Light (VARTML manufacturing method is adopted for manufacturing the flax fiber composite panel. The VARTML is a manufacturing process that the resin is injected into the dry layered –up fibers enclosed by a rigid mold tool under vacuum. In this work, the resin flow analysis of VARTM manufacturing method is performed. A series of flax composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of chemical storage tank for agricultural vehicle was performed using flax/vinyl ester. After structural design and analysis, the resin flow analysis of VARTM manufacturing method was performed

Changduk Kong

2014-08-01

361

Modeling of temperature field and fluid flow in hybrid welding process  

Directory of Open Access Journals (Sweden)

Full Text Available Mathematical and numerical model of the temperature field and the velocity field in melted zone concerning the hybrid laser – arc process was presented in this paper. The temperature field was determined by solution the transient heat transfer equation with activity of inner heat sources. Fluid flow in welding pool was determined by solution of the Navier – Stokes equation in Chorin’s projection. The fuzzy solidification front was assumed in a numerical algorithm with linear approximation of the solid phase in mushy zone. Fluid flow through porous medium was considered in mushy zone according to Darcy’s model. In the base of elaborated models and realized algorithms, results of computer simulations were presented in this study. Temperature distribution in the weld and velocity distribution in melted zone as well as welding pool shape and heat affected zone were illustrated.

W. Piekarska

2009-07-01

362

Preliminary flow sheet and process design for ZnSe thermochemical cycle  

Energy Technology Data Exchange (ETDEWEB)

A preliminary design of the ZnSe cycle for thermochemical hydrogen production has been prepared for use in deriving economic costs for hydrogen production. The process flowsheet identifies key equipment items as well as major streams. Flow and heat loads have been estimated based on one mole of hydrogen output. The thermal efficiency of this cycle depends on two factors: (1) the ability to perform the dissolution of ZnSO/sub 4/ and the hydrolysis of ZnSe with a minimum amount of aqueous HCl, and (2) the ability to match the process heat requirements with available heat from the exothermic steps in the cycle. Estimates of the cycle's thermal efficiency range from 34--57 percent depending upon the process heat utilization.

Otsuki, H. H.; Cox, K. E.

1976-06-21

363

Frequency pattern of turbulent flow and sediment entrainment over ripples using image processing  

Directory of Open Access Journals (Sweden)

Full Text Available River channel change and bed scourings are source of major environmental problem for fish and aquatic habitat. The bed form such as ripples and dunes is the result of an interaction between turbulent flow structure and sediment particles at the bed. The structure of turbulent flow over ripples is important to understand initiation of sediment entrainment and its transport. The focus of this study is the measurement and analysis of the dominant bursting events and the flow structure over ripples in the bed of a channel. Two types of ripples with sinusoidal and triangular forms were tested in this study. The velocities of flow over the ripples were measured in three dimensions using an Acoustic Doppler Velocimeter with a sampling rate of 50 Hz. These velocities were measured at different points within the flow depth from the bed and at different longitudinal positions along the flume. A CCD camera was used to capture 1500 sequential images from the bed and to monitor sediment movement at different positions along the bed. Application of image processing technique enabled us to compute the number of entrained and deposited particles over the ripples. From a quadrant decomposition of instantaneous velocity fluctuations close to the bed, it was found that bursting events downstream of the second ripple, in Quadrants 1 and 3, were dominant whereas upstream of the ripple, Quadrants 2 and 4 were dominant. More importantly consideration of these results indicates that the normalized occurrence probabilities of sweep events along the channel are in phase with the bed forms whereas those of ejection events are out of phase with the bed form. Therefore entrainment would be expected to occur upstream and deposition occurs downstream of the ripple. These expectations were confirmed by measurement of entrained and deposited sediment particles from the bed. These above information can be used in practical application for rivers where restoration is required.

A. Keshavarzi

2012-01-01

364

Frequency pattern of turbulent flow and sediment entrainment over ripples using image processing  

Science.gov (United States)

River channel change and bed scourings are source of major environmental problem for fish and aquatic habitat. The bed form such as ripples and dunes is the result of an interaction between turbulent flow structure and sediment particles at the bed. The structure of turbulent flow over ripples is important to understand initiation of sediment entrainment and its transport. The focus of this study is the measurement and analysis of the dominant bursting events and the flow structure over ripples in the bed of a channel. Two types of ripples with sinusoidal and triangular forms were tested in this study. The velocities of flow over the ripples were measured in three dimensions using an Acoustic Doppler Velocimeter with a sampling rate of 50 Hz. These velocities were measured at different points within the flow depth from the bed and at different longitudinal positions along the flume. A CCD camera was used to capture 1500 sequential images from the bed and to monitor sediment movement at different positions along the bed. Application of image processing technique enabled us to compute the number of entrained and deposited particles over the ripples. From a quadrant decomposition of instantaneous velocity fluctuations close to the bed, it was found that bursting events downstream of the second ripple, in Quadrants 1 and 3, were dominant whereas upstream of the ripple, Quadrants 2 and 4 were dominant. More importantly consideration of these results indicates that the normalized occurrence probabilities of sweep events along the channel are in phase with the bed forms whereas those of ejection events are out of phase with the bed form. Therefore entrainment would be expected to occur upstream and deposition occurs downstream of the ripple. These expectations were confirmed by measurement of entrained and deposited sediment particles from the bed. These above information can be used in practical application for rivers where restoration is required.

Keshavarzi, A.; Ball, J.; Nabavi, H.

2012-01-01

365

River flow forecasting with Artificial Neural Networks using satellite observed precipitation pre-processed with flow length and travel time information: case study of the Ganges river basin  

OpenAIRE

This paper explores the use of flow length and travel time as a pre-processing step for incorporating spatial precipitation information into Artificial Neural Network (ANN) models used for river flow forecasting. Spatially distributed precipitation is commonly required when modelling large basins, and it is usually incorporated in distributed physically-based hydrological modelling approaches. However, these modelling approaches are recognised to be quite complex and expensive, especially due...

Akhtar, M. K.; Corzo, G. A.; Andel, S. J.; Jonoski, A.

2009-01-01

366

Conservação e reúso de águas usando o método Diagrama de Fontes de Água para processos em batelada: estudo de casos / Water conservation and reuse using the Water Sources Diagram method for batch process: case studies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O gerenciamento de recursos hídricos tem sido um fator importante para a sustentabilidade dos processos industriais, visto que há uma necessidade crescente pelo desenvolvimento de metodologias voltadas para conservação e uso racional da água. O objetivo deste trabalho foi aplicar o método Diagrama d [...] e Fontes de Água (DFA), usado na definição de metas de mínimo consumo de água, a processos que operam em regime batelada. Foram gerados e avaliados cenários de reúso de correntes obtidos pela aplicação do método a partir de dados de quantidade de água e concentração de contaminantes nas operações. Foram apresentados dois estudos de caso com o objetivo de demonstrar a redução de consumo de água e da geração de efluentes, além de custos de tratamento final e de investimento em tanques de estocagem, em relação à configuração inicial. Os cenários mostraram-se bastante promissores, com reduções que alcançam 45%, em termos de consumo hídrico e geração de efluentes, e 37%, em termos de custos de tanques, sem a necessidade de processos de regeneração. Com isso, a técnica empregada mostrou-se relevante e flexível como alternativa às ferramentas sistemáticas voltadas para a minimização do consumo de água em processos industriais, exercendo importante papel em um programa de gerenciamento de recursos hídricos. Abstract in english The water resources management has been an important factor for the sustainability of industrial processes, since there is a growing need for the development of methodologies aimed at the conservation and rational use of water. The objective of this work was to apply the heuristic-algorithmic method [...] called Water Sources Diagram (WSD), which is used to define the target of minimum water consumption, to batch processes. Scenarios with reuse of streams were generated and evaluated with application of the method from the data of water quantity and concentration of contaminants in the operations. Two case studies aiming to show the reduction of water consumption and wastewater generation, and final treatment costs besides investment in storage tanks, were presented. The scenarios showed great promising, achieving reduction up to 45% in water consumption and wastewater generation, and a reduction of around 37% on cost of storage tanks, without the need to allocate regeneration processes. Thus, the WSD method showed to be a relevant and flexible alternative regarding to systemic tools aimed at minimizing the consumption of water in industrial processes, playing an important role within a program of water resources management.

Reinaldo Coelho, Mirre; Shaula Christine Leal, Ferreira; Aline Rodrigues, Dias; Fernando Luiz Pellegrini, Pessoa.

2012-03-01

367

Bosonic Loop Diagrams as Perturbative Solutions of the Classical Field Equations in $\\phi^4$-Theory  

CERN Document Server

Solutions of the classical $\\phi^4$-theory in Minkowski space-time are analyzed in a perturbation expansion in the nonlinearity. Using the language of Feynman diagrams, the solution of the Cauchy problem is expressed in terms of tree diagrams which involve the retarded Green's function and have one outgoing leg. In order to obtain general tree diagrams, we set up a "classical measurement process" in which a virtual observer of a scattering experiment modifies the field and detects suitable energy differences. By adding a classical stochastic background field, we even obtain all loop diagrams. The expansions are compared with the standard Feynman diagrams of the corresponding quantum field theory.

Finster, Felix

2012-01-01

368

Bosonic Loop Diagrams as Perturbative Solutions of the Classical Field Equations in ?4-Theory  

Science.gov (United States)

Solutions of the classical ?4-theory in Minkowski space-time are analyzed in a perturbation expansion in the nonlinearity. Using the language of Feynman diagrams, the solution of the Cauchy problem is expressed in terms of tree diagrams which involve the retarded Green's function and have one outgoing leg. In order to obtain general tree diagrams, we set up a "classical measurement process" in which a virtual observer of a scattering experiment modifies the field and detects suitable energy differences. By adding a classical stochastic background field, we even obtain all loop diagrams. The expansions are compared with the standard Feynman diagrams of the corresponding quantum field theory.

Finster, Felix; Tolksdorf, Jürgen

2012-05-01

369

Toxic metals in WEEE: Characterization and substance flow analysis in waste treatment processes  

International Nuclear Information System (INIS)

Waste electrical and electronic equipment (WEEE) has received extensive attention as a secondary source of metals. Because WEEE also contains toxic substances such as heavy metals, appropriate management of these substances is important in the recycling and treatment of WEEE. As a basis for discussion toward better management of WEEE, this study characterizes various types of WEEE in terms of toxic metal contents. The fate of various metals contained in WEEE, including toxic metals, was also investigated in actual waste treatment processes. Cathode-ray tube televisions showed the highest concentration and the largest total amount of toxic metals such as Ba, Pb, and Sb, so appropriate recycling and disposal of these televisions would greatly contribute to better management of toxic metals in WEEE. A future challenge is the management of toxic metals in mid-sized items such as audio/visual and ICT equipment because even though the concentrations were not high in these items, the total amount of toxic metals contained in them is not negligible. In the case of Japan, such mid-sized WEEE items as well as small electronic items are subject to municipal solid waste treatment. A case study showed that a landfill was the main destination of toxic metals contained in those items in the current treatment systems. The case study also showed that changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. Because the flow changes might lead to an increase in the amount of toxic metals released to the environment, the flows of toxic metals and the materials targeted for resource recovery should be considered simultaneously. - Highlights: ? Appropriate management of toxic metals contained in WEEE is important during recycling and treatment of WEEE. ? CRT TVs contain large amount of toxic metals with high concentration and thus appropriate management is highly important. ? Mid-sized equipment is a future target for managing toxic metals in WEEE because the total amount is not negligible. ? Changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. ? The flows of toxic metals and valuable materials should be managed simultaneously in recycling and treatment of WEEE

370

Toxic metals in WEEE: Characterization and substance flow analysis in waste treatment processes  

Energy Technology Data Exchange (ETDEWEB)

Waste electrical and electronic equipment (WEEE) has received extensive attention as a secondary source of metals. Because WEEE also contains toxic substances such as heavy metals, appropriate management of these substances is important in the recycling and treatment of WEEE. As a basis for discussion toward better management of WEEE, this study characterizes various types of WEEE in terms of toxic metal contents. The fate of various metals contained in WEEE, including toxic metals, was also investigated in actual waste treatment processes. Cathode-ray tube televisions showed the highest concentration and the largest total amount of toxic metals such as Ba, Pb, and Sb, so appropriate recycling and disposal of these televisions would greatly contribute to better management of toxic metals in WEEE. A future challenge is the management of toxic metals in mid-sized items such as audio/visual and ICT equipment because even though the concentrations were not high in these items, the total amount of toxic metals contained in them is not negligible. In the case of Japan, such mid-sized WEEE items as well as small electronic items are subject to municipal solid waste treatment. A case study showed that a landfill was the main destination of toxic metals contained in those items in the current treatment systems. The case study also showed that changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. Because the flow changes might lead to an increase in the amount of toxic metals released to the environment, the flows of toxic metals and the materials targeted for resource recovery should be considered simultaneously. - Highlights: ? Appropriate management of toxic metals contained in WEEE is important during recycling and treatment of WEEE. ? CRT TVs contain large amount of toxic metals with high concentration and thus appropriate management is highly important. ? Mid-sized equipment is a future target for managing toxic metals in WEEE because the total amount is not negligible. ? Changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. ? The flows of toxic metals and valuable materials should be managed simultaneously in recycling and treatment of WEEE.

Oguchi, Masahiro, E-mail: oguchi.masahiro@nies.go.jp; Sakanakura, Hirofumi; Terazono, Atsushi

2013-10-01

371

MODELING COUPLED PROCESSES OF MULTIPHASE FLOW AND HEAT TRANSFER IN UNSATURATED FRACTURED ROCK  

International Nuclear Information System (INIS)

A mountain-scale, thermal-hydrologic (TH) numerical model is developed for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository at Yucca Mountain, Nevada, USA. The TH model, consisting of three-dimensional (3-D) representations of the unsaturated zone, is based on the current repository design, drift layout, and thermal loading scenario under estimated current and future climate conditions. More specifically, the TH model implements the current geological framework and hydrogeological conceptual models, and incorporates the most updated, best-estimated input parameters. This mountain-scale TH model simulates the coupled TH processes related to mountain-scale multiphase fluid flow, and evaluates the impact of radioactive waste heat on the hydrogeological system, including thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. For a better description of the ambient geothermal condition of the unsaturated zone system, the TH model is first calibrated against measured borehole temperature data. The ambient temperature calibration provides the necessary surface and water table boundary as well as initial conditions. Then, the TH model is used to obtain scientific understanding of TH processes in the Yucca Mountain unsaturated zone under the designed schedule of repository thermal load

372

Effect of rheology on flow displacement during cementing process in oil wells  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a set of numerical simulations of the displacement flow of three non-Newtonian fluids through annular eccentric wells. The main application of this work is the studying of drilling and completion processes of oil wells where a cement slurry pushes the drilling mud, used in the drilling process to lubricate the drill and to remove the produced drilling cuts. To avoid contamination, a spacer fluid is usually inserted between them. Both drilling mud and cement slurry behave as non-Newtonian fluids, and the spacer fluid can be Newtonian or non-Newtonian. The analysis of flow and interface configuration between these fluids helps to determine contamination, and is an important tool for the process optimization. The numerical solution of the governing conservation equations of mass and momentum is obtained with the Fluent software, using the finite volume technique and the volume of fluid method. The effects of rheological parameters, density ratios and pumped volume of the spacer fluid are investigated. The results obtained show that the displacement is better when a more viscous spacer fluid is used. The results also show that using lower amounts of the spacer fluid can lead to contamination, which is worse in the smaller gap region of the annular space, in the case of non-rectilinear well. It was also observed that the density ratios play a major role in the cementing operation. (author)

Braghini, Andre; Naccache, Monica F.; Fonseca, Marcos I. [Dept. Mechanical Engineering. Pontificia Universidade Catolica (PUR-Rio), Rio de Janeiro, RJ (Brazil)], e-mails: mnaccache@puc-rio.br; Miranda, Cristiane R. de; Martins, Andre L.; Aranha, Pedro E. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)], e-mails: crisrichard@petrobras.com.br, aleibsohn@petrobras.com.br, pearanha@petrobras.com.br

2010-07-01

373

Corrosion barriers processed by Al electroplating and their resistance against flowing Pb-15.7Li  

Science.gov (United States)

In the HCLL blanket design, ferritic-martensitic steels are in direct contact with the flowing liquid breeder Pb-15.7Li and have to withstand severe corrosion attack. Beyond corrosion, T-permeation from the breeder into the RAFM-steels is also an important issue and has to be reduced significantly. Earlier work showed that Al-based coatings can act as barriers for both, however, applied processes e.g. HDA or VPS exhibited strong drawbacks in the past. Meanwhile new industrial relevant coating processes, using electroplating technology are under development and called ECA (electrochemical aluminization) and ECX (electrochemical deposition from ionic liquids) process. In this study electrochemically Al-coated and heat-treated Eurofer samples were tested in PICOLO loop for exposure times up to 12,000 h (ECA) and 2000 h (first results ECX) respectively to determine corrosion properties in flowing Pb-15.7Li (550 °C, 0.1 m/s). Cross section analysis afterward corrosion testing proved the ability of thin Al-based barriers made by electrochemical techniques to protect the bare Eurofer from corrosion attack even at exposure times of 12,000 h. Determined radial corrosion rates lay between 10 and 20 ?m/a. First results for ECX coated samples (2000 h) revealed more homogeneous corrosion behavior of the barrier layer itself compared to ECA.

Krauss, Wolfgang; Konys, Jürgen; Wulf, Sven-Erik

2014-12-01

374

The study of flow pattern and phase-change problem in die casting process  

Science.gov (United States)

The flow pattern and solidification phenomena in die casting process have been investigated in the first phase study. The flow pattern in filling process is predicted by using a VOF (volume of fluid) method. A good agreement with experimental observation is obtained for filling the water into a die cavity with different gate geometry and with an obstacle in the cavity. An enthalpy method has been applied to solve the solidification problem. By treating the latent heat implicitly into the enthalpy instead of explicitly into the source term, the CPU time can be reduced at least 20 times. The effect of material properties on solidification fronts is tested. It concludes that the dependence of properties on temperature is significant. The influence of the natural convection over the diffusion has also been studied. The result shows that the liquid metal solidification phenomena is diffusion dominant, and the natural convection can affect the shape of the interface. In the second phase study, the filling and solidification processes will be considered simultaneously.

Wang, T. S.; Wei, H.; Chen, Y. S.; Shang, H. M.

1996-01-01

375

A flow-through chromatography process for influenza A and B virus purification.  

Science.gov (United States)

Vaccination is still the most efficient measure to protect against influenza virus infections. Besides the seasonal wave of influenza, pandemic outbreaks of bird or swine flu represent a high threat to human population. With the establishment of cell culture-based processes, there is a growing demand for robust, economic and efficient downstream processes for influenza virus purification. This study focused on the development of an economic flow-through chromatographic process avoiding virus strain sensitive capture steps. Therefore, a three-step process consisting of anion exchange chromatography (AEC), Benzonase(®) treatment, and size exclusion chromatography with a ligand-activated core (LCC) was established, and tested for purification of two influenza A virus strains and one influenza B virus strain. The process resulted in high virus yields (?68%) with protein contamination levels fulfilling requirements of the European Pharmacopeia for production of influenza vaccines for human use. DNA was depleted by ?98.7% for all strains. The measured DNA concentrations per dose were close to the required limits of 10ng DNA per dose set by the European Pharmacopeia. In addition, the added Benzonase(®) could be successfully removed from the product fraction. Overall, the presented downstream process could potentially represent a simple, robust and economic platform technology for production of cell culture-derived influenza vaccines. PMID:24992667

Weigel, Thomas; Solomaier, Thomas; Peuker, Alessa; Pathapati, Trinath; Wolff, Michael W; Reichl, Udo

2014-10-01

376

The Amplituhedron from Momentum Twistor Diagrams  

OpenAIRE

We propose a new diagrammatic formulation of the all-loop scattering amplitudes/Wilson loops in planar N=4 SYM, dubbed the "momentum-twistor diagrams". These are on-shell-diagrams obtained by gluing trivalent black and white vertices defined in momentum twistor space, which, in the reduced diagram case, are known to be related to diagrams in the original twistor space. The new diagrams are manifestly Yangian invariant, and they naturally represent factorization and forward-l...

Bai, Yuntao; He, Song

2014-01-01

377

Phase diagram for assembly of biologically-active peptide amphiphiles.  

Science.gov (United States)

We construct a phase diagram for self-assembling biologically active peptide amphiphiles. The structure and stability of the assemblies are studied as a function of pH and salinity of the solution. The general features of the phase diagram are predicted based on theoretical modeling of the self-assembly process, as well as experimental data, and further experiments are performed to verify and ascertain the boundary locations of the diagram. Depending on solution conditions, the amphiphiles can form cylindrical or spherical micelles, intermediate structures between these, or may not assemble at all. We also demonstrate that changing conditions may result in phase transitions among these structures. This type of phase diagram could be useful in the design of certain supramolecular nanostructures by providing information on the necessary conditions to form them. PMID:18088110

Tsonchev, Stefan; Niece, Krista L; Schatz, George C; Ratner, Mark A; Stupp, Samuel I

2008-01-17

378

Interface flow process audit: using the patient's career as a tracer of quality of care and of system organisation  

Directory of Open Access Journals (Sweden)

Full Text Available Objectives: This case study aims to demonstrate the method's feasibility and capacity to improve quality of care. Several drawbacks attached to tracer condition and selected procedure audits oblige clinicians to rely on external evaluators. Interface flow process audit is an alternative method, which also favours integration of health care across institutions divide. Methods: An action research study was carried out to test the feasibility of interface flow process audit and its impact on quality improvement. An anonymous questionnaire was carried out to assess the participants' perception of the process. Results: In this study, interface flow process audit brought together general practitioners and hospital doctors to analyse the co-ordination of their activities across the primary-secondary interface. Human factors and organisational characteristics had a clear influence on implementation of the solutions. In general, the participants confirmed that the interface flow process audit helped them to analyse the quality of case management both at primary and secondary care level. Conclusions: The interface flow process audit appears a useful method for regular in-service self-evaluation. Its practice enabled to address a wide scope of clinical, managerial and economical problems. Bridging the primary-secondary care gap, interface flow process audit's focus on the patient's career combined with the broad scope of problems that can be analysed are particularly powerful features. The methodology would benefit from an evaluation of its practice on larger scale.

Jean-Pierre Unger

2004-05-01

379

Influence of Mass Transfer Processes on Couette Flow of Magnetic Fluid  

Directory of Open Access Journals (Sweden)

Full Text Available This article describes the results of a theoretical study of magnetic fluid two-dimensional Couett flow in magnetic fluid seal model in view of mass transfer processes. It has been shown that very inhomogeneous magnetic field in seal gap lead to magnetic particle concentration rearrangement due to magnetophoresis and Brownian diffusion. In turn, it lead to inhomogeneous magnetic fluid viscosity and change in local and integral shearing force at channel walls. Integral shearing force has been shown to depend on magnetic field and magnetic fluid parameters. Closely-packed fluid density distribution conditions have been defined. Proposed theory covers real magnetic fluid seal performance features adequately.

V.G. Bashtovoi

2013-12-01

380

Numerical simulation of free surface flows in die casting injection processes  

OpenAIRE

This paper presents a numerical study of the flow of molten metal in the shot sleeve of horizontal high-pressure die-casting machines during the injection process. The analysis of the wave of molten metal created by plunger motion can be of help in reducing porosity in manufactured parts caused by entrapment in the molten metal of a certain amount of the initial air in the die cavity and in the shot sleeve. The amount of trapped air can be reduced by selecting appropriate operating cond...

Go?mez-del-pino, Pablo Joaqui?n; Lo?pez Rodri?guez, Joaqui?n; Faura Mateu, Fe?lix; Herna?ndez Rodri?guez, Julio

2000-01-01

381

Finite element simulation of dynamic wetting flows as an interface formation process  

OpenAIRE

A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem of capillary rise. The motivation for this work comes from the fact that, as discovered experimentally more than a decade ago, the key variable in dynamic wetting flows - the dynamic contact angle - depends not just on the velocity of the three-phase contac...

Sprittles, Je; Shikhmurzaev, Yd

2013-01-01

382

Simplifying the Scientific Writing and Review Process with SciFlow  

Directory of Open Access Journals (Sweden)

Full Text Available Scientific writing is an essential part of a student’s and researcher’s everyday life. In this paper we investigate the particularities of scientific writing and explore the features and limitations of existing tools for scientific writing. Deriving from this analysis and an online survey of the scientific writing processes of students and researchers at the University of Paderborn, we identify key principles to simplify scientific writing and reviewing. Finally, we introduce a novel approach to support scientific writing with a tool called SciFlow that builds on these principles and state of the art technologies like cloud computing.

Wolfgang Reinhardt

2010-12-01

383

Neutron monitors for monitoring process and waste flow in a reprocessing plant  

International Nuclear Information System (INIS)

The detection of neutrons offers the possibility of determining the plutonium and monitoring the criticality directly at the part of the plant concerned. The state of neutron monitor development and the basic possibilities of application for process and safety monitoring are shown. Requirements for the equipment and necessary quality assurance measures are discussed with examples. Examples are explained for passive neutron measurement (Pu cleaning cycles, Pu loading of refined material flow) and for the active measurement of neutrons using a steady neutron source (Pu and Cm/Pu on fuel element cans, criticality for vibration of rods, fuel element monitors etc.). (orig./RB)

384

Deriving bedform phase diagrams  

Science.gov (United States)

Students prepare for this activity by working with a unidirectional flume with a sand bed. We adjust water depth, flow velocity, and channel slope to achieve a range of bed states, in an effort for them to understand the controls on bedforms. This portion of the activity could be done in lecture or via another exercise that makes use of digital video of actual experiments. The activity itself is a jigsaw: students form groups of three, each group responsible for plotting depth vs. velocity plots of bedform state for a single sand grain size range (0.10-0.14 mm, 0.5-0.64 mm, and 1.3-1.8 mm). These data are provided to them as Excel files and the data were directly 'stolen' from the original depth vs. velocity plots in Middleton and Southard (1984), Mechanics of Sediment Movement, SEPM Short Course Number 3. Datathief software (available free on the web) was used to steal the data. The data are arranged in columns: depth, velocity, and bedform type. Students must plot each of the different bedform types with a different symbol, then they have to define field boundaries. It is critical that they have never seen the original plots in their textbook. The goal is for them to derive them on their own, not to regurgitate what is in their textbook or elsewhere. After they complete their plots for each grain size range, the groups re-arrange themselves into groups of three with one representative from each of the grain size groups. They then must try to evaluate the effects of changing grain size on bedform state. Finally, after completing the exercise, the bedform analysis is linked to the cross stratification that is produced under conditions of high sediment fallout rates and the given bed state. The activity gives students practice working with realistic datasets, exposure to the role of physical modeling in sedimentary geology, and a chance to plot and interpret real data. Furthermore, it really solidifies the link between cross stratification and its dynamic interpretation from the rock record.

Hickson, Tom

385

The Quasar SED Mixing Diagram  

Science.gov (United States)

We present a useful new diagram for characterizing the quasar-host-reddening mixture for AGN SEDs. This "mixing diagram" is based on a detailed study of 413 X-ray selected Type 1 AGN SEDs from the XMM-COSMOS Survey (Elvis, Hao, et al., 2011). The mixing diagram plots the near-IR (1-3micron) spectral slope against the optical (0.3-1micron) slope to form a generalized 'color-color' diagram. A pure AGN continuum (Elvis et al., 1994, E94) and pure host galaxies are located at clear and distinct positions on the mixing diagram. The lines joining them indicate the fraction of host contribution to each AGN. The reddening vector is almost perpendicular to these mixing lines, and so is easily measured independently. The mixing diagram shows that 90% of the AGNs lie on mixing curves between the mean E94 AGN SED and a host galaxy, with only modest reddening [E(B-V)=0.1-0.2] (Hao et al., 2011a). Lower luminosity and lower Eddington ratio AGNs have a larger host galaxy fraction, as expected. Optically selected samples (SDSS) have smaller host galaxy fractions. There is some intrinsic scatter around the E94 mean SED. A substantial minority, 10%, of the XMM-COSMOS AGNs are inconsistent with any AGN+host+reddening mix. These AGNs have weak or non-existent near-IR bumps, suggesting a lack of the hot dust characteristic of AGNs (Hao et al., 2010). A similar fraction of these "hot dust poor" (HDP) quasars are found in the Elvis et al. 1994 (BQS) and Richards et al. 2006 (SDSS) samples (Hao et al., 2011b). The fraction of "hot dust poor" AGNs grows to 20% at z>2 (Hao et al. 2010). The proposed 'cosmic cycle' of SMBH and galaxy co-evolution (e.g. Hopkins et al., 2006) can be shown as tracks on the mixing diagram. The mixing diagram definition could also be expanded to other wavelengths.

Hao, Heng; Elvis, M.; Civano, F.

2011-05-01

386

Simulation of Coupled Processes of Flow, Transport, and Storage of CO2 in Saline Aquifers  

Energy Technology Data Exchange (ETDEWEB)

This report is the final scientific one for the award DE- FE0000988 entitled “Simulation of Coupled Processes of Flow, Transport, and Storage of CO2 in Saline Aquifers.” The work has been divided into six tasks. In task, “Development of a Three-Phase Non-Isothermal CO2 Flow Module,” we developed a fluid property module for brine-CO2 mixtures designed to handle all possible phase combinations of aqueous phase, sub-critical liquid and gaseous CO2, supercritical CO2, and solid salt. The thermodynamic and thermophysical properties of brine-CO2 mixtures (density, viscosity, and specific enthalpy of fluid phases; partitioning of mass components among the different phases) use the same correlations as an earlier fluid property module that does not distinguish between gaseous and liquid CO2-rich phases. We verified the fluid property module using two leakage scenarios, one that involves CO2 migration up a blind fault and subsequent accumulation in a secondary “parasitic” reservoir at shallower depth, and another investigating leakage of CO2 from a deep storage reservoir along a vertical fault zone. In task, “Development of a Rock Mechanical Module,” we developed a massively parallel reservoir simulator for modeling THM processes in porous media brine aquifers. We derived, from the fundamental equations describing deformation of porous elastic media, a momentum conservation equation relating mean stress, pressure, and temperature, and incorporated it alongside the mass and energy conservation equations from the TOUGH2 formulation, the starting point for the simulator. In addition, rock properties, namely permeability and porosity, are functions of effective stress and other variables that are obtained from the literature. We verified the simulator formulation and numerical implementation using analytical solutions and example problems from the literature. For the former, we matched a one-dimensional consolidation problem and a two-dimensional simulation of the Mandel-Cryer effect. For the latter, we obtained a good match of temperature and gas saturation profiles, and surface uplift, after injection of hot fluid into a model of a caldera structure. In task, “Incorporation of Geochemical Reactions of Selected Important Species,” we developed a novel mathematical model of THMC processes in porous and fractured saline aquifers, simulating geo-chemical reactions associated with CO2 sequestration in saline aquifers. Two computational frameworks, sequentially coupled and fully coupled, were used to simulate the reactions and transport. We verified capabilities of the THMC model to treat complex THMC processes during CO2 sequestration by analytical solutions and we constructed reactive transport models to analyze the THMC process quantitatively. Three of these are 1D reactive transport under chemical equilibrium, a batch reaction model with equilibrium chemical reactions, and a THMC model with CO2 dissolution. In task “Study of Instability in CO2 Dissolution-Diffusion-Convection Processes,” We reviewed literature related to the study of density driven convective flows and on the instability of CO2 dissolution-diffusion-convection processes. We ran simulations that model the density-driven flow instability that would occur during CO2 sequestration. CO2 diffused through the top of the system and dissolved in the aqueous phase there, increasing its density. Density fingers formed along the top boundary, and coalesced into a few prominent ones, causing convective flow that forced the fluid to the system bottom. These simulations were in two and three dimensions. We ran additional simulations of convective mixing with density contrast caused by variable dissolved CO2 concentration in saline water, modeled after laboratory experiments in which supercritical CO2 was circulated in the headspace above a brine saturated packed sand in a pressure vessel. As CO2 dissolved into the upper part of the saturated sand, liquid phase density increases causing instability and setting off convective mixing. We obtained good agreement

Wu, Yu-Shu; Chen, Zizhong; Kazemi, Hossein; Yin, Xiaolong; Pruess, Karsten; Oldenburg, Curt; Winterfeld, Philip; Zhang, Ronglei

2014-09-30

387

Transformation of BPMN Diagrams to YAWL Nets  

Directory of Open Access Journals (Sweden)

Full Text Available Business Process Modeling Notation (BPMN is the de facto standard for modeling business processes on a conceptual level. However, BPMN lacks a formal semantics and many of its features need to be further interpret, Consequently that hinders  BPMN as a standard to statically check the semantic correctness of models. YAWL (Yet Another Workflow Language allows the specification of executable workflow models. A transformation between these two languages enables the integration of different levels of abstraction in process modeling. This paper discusses how to transform BPMN diagrams to YAWL nets. The benefits of the transformation are threefold. Firstly, it clarifies the semantics of BPMN via a mapping to YAWL. Secondly, the deployment of BPMN business process models is simplified. Thirdly, BPMN models can be analyzed with YAWL verification tools.

Jianhong Ye

2010-04-01

388

Determination of sulfate in the wet-process of phosphoric acid by reverse flow injection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english An improved method based on reverse flow injection is proposed for determining sulfate concentration in the wet-process of phosphoric acid (WPA). The effect of reagent composition, flow rate, temperature, acid concentration, length of the reaction coil, and linear response range on the flow system i [...] s discussed in detail. Optimal conditions are established for determining sulfate in the WPA samples. Baseline drift is avoided by a periodic washing step with EDTA in an alkaline medium. A linear response is observed within a range of 20 - 360 mg L-1, given by the equation A = 0.0020C (mg L-1) + 0.0300, R² = 0.9991. The detection limit of the proposed method for sulfate analysis is 3 mg L-1, and the relative standard deviation (n = 12) of sulfate absorbance peak is less than 1.60%. This method has a rate of up to 29 samples per hour, and the results compare well with those obtained with gravimetric method.

Wenhui, Shi; Lin, Yang; Quanjun, Fu; Zhiye, Zhang; Xinlong, Wang.

1357-13-01

389

Finite Element Simulation of Dynamic Wetting Flows as an Interface Formation Process  

CERN Document Server

A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem of capillary rise. The motivation for this work comes from the fact that, as discovered experimentally more than a decade ago, the key variable in dynamic wetting flows -the dynamic contact angle - depends not just on the velocity of the three-phase contact line but on the entire flow field/geometry. Hence, to describe this effect, it becomes necessary to use the mathematical model that has this dependence as its integral part. A new physical effect, termed the `hydrodynamic resist to dynamic wetting', is discovered where the influence of the capillary's radius on the dynamic contact angle, and hence on the global flow, is computed. The capabilities of the numerical framework are then demonstrated by comparing the results to experiments on the unsteady capillary rise, where...

Sprittles, James

2012-01-01

390

Finite element simulation of dynamic wetting flows as an interface formation process  

Science.gov (United States)

A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem of capillary rise. The motivation for this work comes from the fact that, as discovered experimentally more than a decade ago, the key variable in dynamic wetting flows — the dynamic contact angle — depends not just on the velocity of the three-phase contact line but on the entire flow field/geometry. Hence, to describe this effect, it becomes necessary to use the mathematical model that has this dependence as its integral part. A new physical effect, termed the 'hydrodynamic resist to dynamic wetting', is discovered where the influence of the capillary's radius on the dynamic contact angle, and hence on the global flow, is computed. The capabilities of the numerical framework are then demonstrated by comparing the results to experiments on the unsteady capillary rise, where excellent agreement is obtained. Practical recommendations on the spatial resolution required by the numerical scheme for a given set of non-dimensional similarity parameters are provided, and a comparison to asymptotic results available in limiting cases confirms that the code is converging to the correct solution. The appendix gives a user-friendly step-by-step guide specifying the entire implementation and allowing the reader to easily reproduce all presented results, including the benchmark calculations.

Sprittles, J. E.; Shikhmurzaev, Y. D.

2013-01-01

391

Experimental determination of the flow capacity coefficient for control valves of process  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english A test bench was conceived in order to determine experimentally the flow coefficient [C V] for process control valves, operating with compressible fluids, under established regulations by the standards ANSI/ISA-75.02-1996 and ANSI/ISA-75.01.01-2002. This test bench is used to verify the calibration [...] of valves with continually variable opening, after they have been repaired. The measurements in the test bench allow establishing the C V of these valves for various opening percentages. It was necessary to go through the C V equation for compressible fluids, to proceed with the flow sensor selection. This equation was obtained under similarity conditions by the equality of Euler numbers between prototype and model (test specimen). It is also described the electronic instrumentation for measuring flow, temperature and pressure difference, the design and the development of electronic circuits which control the instrumentation, and the algorithms for the operation and acquisition of measurements.

G., Aragón-Camarasa; G., Aragón-González; A., Canales-Palma; A., León-Galicia.

2009-01-01

392

Interface flow process audit: using the patient's career as a tracer of care and of system organisation  

OpenAIRE

OBJECTIVES: This case study aims to demonstrate the method's feasibility and capacity to improve quality of care. Several drawbacks attached to tracer condition and selected procedure audits oblige clinicians to rely on external evaluators. Interface flow process audit is an alternative method, which also favours integration of health care across institutions divide. METHODS: An action research study was carried out to test the feasibility of interface flow process audit and its impact on qua...

Unger, J. P.; Marchal, B.; Dugas, S.; Wuidar, M. J.; Burdet, D.; Leemans, P.; Unger, J.

2004-01-01

393

Preliminary economic evaluation of the Alkox process  

International Nuclear Information System (INIS)

A new chemical process has been invented at Battelle Pacific Northwest Laboratories for converting alkanes to alcohols. This new chemistry has been named the ''Alkox Process.'' Pacific Northwest Laboratory prepared a preliminary economic analysis for converting cyclohexane to cyclohexanol, which may be one of the most attractive applications of the Alkox process. A process flow scheme and a material balance were prepared to support rough equipment sizing and costing. The results from the economic analysis are presented in the non-proprietary section of this report. The process details, including the flow diagram and material balance, are contained in separate section of this report that is proprietary to Battelle. 7 refs., 4 tabs

394

Streamline topology and dilute particle dynamics in a Karman vortex street flow  

OpenAIRE

Three types of streamline topology in a Karman vortex street flow are shown under the variation of spatial parameters. For the motion of dilute particles in the K\\'arm\\'an vortex street flow, there exist a route of bifurcation to a chaotic orbit and more attractors in a bifurcation diagram for the proportion of particle density to fluid density. Along with the increase of spatial parameters in the flow filed, the bifurcation process is suspended, as well as more and more att...

Wu, Zuo-bing

2004-01-01

395

Removal of paraquat and linuron from water by continuous flow adsorption/ ultrafiltration membrane processes  

International Nuclear Information System (INIS)

The magnetic activated carbon (MAC) was prepared, characterized and compared with powdered activated carbon (PAC) for its adsorptive parameters. Both adsorbents were then used in combination ultrafiltration (UF) membrane as pretreatment for the removal of paraquat and linuron from water. The comparison of membrane parameters like percent retention, permeate flux and backwash times for PAC/UF and MAC/UF hybrid processes showed that percent retention of paraquat and linuron was high for PAC due to its high surface area. However due to cake formation over membrane surface the decline permeate fluxes and long backwash times for PAC were observed. PAC also caused blackening of pipes and flow meter. MAC (an iron oxide and PAC composite) was removed from slurry through magnet thus no cake formation and secondary problems observed for PAC was not encountered. Also the backwash times were minimum for MAC/UF process. (author)

396

A work process and information flow description of control room operations  

International Nuclear Information System (INIS)

The control room workplace is the location from which all plant operations are supervised and controlled on a shift-to-shift basis. The activities comprising plant operations are structured into a number of work processes, and information is the common currency that is used to convey work requirements, communicate business and operating decisions, specify work practice, and describe the ongoing plant and work status. This paper describes the motivation for and early experience with developing a work process and information flow model of CANDU control room operations, and discusses some of the insights developed from model examination that suggest ways in which changes in control centre work specification, organization of resources, or asset layout could be undertaken to achieve operational improvements. (author)

397

Performance Analysis Of Various Anti-Reset Windup Algorithms For A Flow Process Station  

Directory of Open Access Journals (Sweden)

Full Text Available The study was aimed to develop the various aspects of Anti reset windup or Integral windup and also the different algorithms available to eliminate the phenomenon of windup. Different open loop responses were obtained from a Flow process Station using MATLAB and SIMULINK and VI Microsystems process control software. The open loop responses were evaluated and different system models were generated using the two point method. The system models were found to follow a decreasing order of Gain values and an increasing order of Td and T values. A SIMULINK model was obtained to implement Back calculation combined with Conditional Integration. The models for the system obtained were simulated using the SIMULINK model and a PID controller and the closed loop responses were generated. The closed loop responses using a PID controller with Back calculation and Conditional integration were found to follow the set point as expected.

Shaunak Chakrabartty

2014-05-01

398

Heat flow processes in the positive column of a glow discharge  

International Nuclear Information System (INIS)

The electronic thermal conductivity of ionised gases such as air, hydrogen, nitrogen and oxygen has been measured for discharge currents varying from 2 mA to 8 mA. The problem of heat flow processes in the positive column of the glow discharge has been investigated utilizing the first order perturbation technique to Boltzmann Transport equation incorporating the radial distribution of charged particles which is assumed to be Bessalian. The loss is due to heat conductivity of electrons, ions and neutral particles and also due to ambipolar diffusion of electrons. The experimental results enable to calculate separately the contribution by different processes and it is observed that the major part of the heat loss is due to diffusion. Further from the experimental results it has been possible to calculate

399

Evaluating the flow processes in ultrafine-grained materials at elevated temperatures  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english When polycrystalline materials are tested in tension at elevated temperatures, the flow mechanisms depend upon various parameters including the temperature of testing, the applied stress and the material grain size. The plotting of deformation mechanism maps is a procedure used widely in displaying [...] and interpreting the creep properties of conventional coarse-grained metals but there have been few attempts to date to use this same procedure for ultrafine-grained and nanocrystalline materials produced through the application of severe plastic deformation (SPD). This report examines the potential for using deformation mechanism mapping for materials processed by SPD and presents examples for materials processed using equal-channel angular pressing and high-pressure torsion.

Megumi, Kawasaki; Terence G., Langdon.

2013-06-01

400

Effects of flow scarcity on leaf-litter processing under oceanic climate conditions in calcareous streams.  

Science.gov (United States)

Although temporary streams represent a high proportion of the total number and length of running waters, historically the study of intermittent streams has received less attention than that of perennial ones. The goal of the present study was to assess the effects of flow cessation on litter decomposition in calcareous streams under oceanic climate conditions. For this, leaf litter of alder was incubated in four streams (S1, S2, S3 and S4) with different flow regimes (S3 and S4 with zero-flow periods) from northern Spain. To distinguish the relative importance and contribution of decomposers and detritivores, fine- and coarse-mesh litter bags were used. We determined processing rates, leaf-C, -N and -P concentrations, invertebrate colonization in coarse bags and benthic invertebrates. Decomposition rates in fine bags were similar among streams. In coarse bags, only one of the intermittent streams, S4, showed a lower rate than that in the other ones as a consequence of lower invertebrate colonization. The material incubated in fine bags presented higher leaf-N and -P concentrations than those in the coarse ones, except in S4, pointing out that the decomposition in this stream was driven mainly by microorganisms. Benthic macroinvertebrate and shredder density and biomass were lower in intermittent streams than those in perennial ones. However, the bags in S3 presented a greater amount of total macroinvertebrates and shredders comparing with the benthos. The most suitable explanation is that the fauna find a food substrate in bags less affected by calcite precipitation, which is common in the streambed at this site. Decomposition rate in coarse bags was positively related to associated shredder biomass. Thus, droughts in streams under oceanic climate conditions affect mainly the macroinvertebrate detritivore activity, although macroinvertebrates may show distinct behavior imposed by the physicochemical properties of water, mainly travertine precipitation, which can override the flow intermittence effects. PMID:24962591

Martínez, Aingeru; Pérez, Javier; Molinero, Jon; Sagarduy, Mikel; Pozo, Jesús

2015-01-15

401

Flow and sediment processes in a cutoff meander of the Danube Delta during episodic flooding  

Science.gov (United States)

This article analyzes the water and suspended solid fluxes through a straightened meander of the southern branch of the Danube Delta (the St. George branch) during episodic flooding. The Mahmudia study site corresponds to a vast natural meander which was cut off in 1984-1988 by an artificial canal opened to shipping. The meander correction accelerated fluxes through the artificial canal and dramatically enhanced deposition in the former meander. After his formation, the cutoff meander acted as sediment storage locations, essentially removing channel and point bar sediments from the active sediment budget of the main channel. Increases in slope and stream power in reaches upstream and downstream have also occurred, but to a lesser degree. During the one-hundred-year recurrent flood in April 2006, bathymetry, flow velocity and discharge data were acquired across several sections of both natural and artificial channels with an acoustic Doppler current profiler (aDcp Workhorse Sentinel 600 kHz, Teledyne RDI) in order to investigate the distribution of the flow and sediment and his impact on sedimentation in a channelized reach and its adjacent cutoff. The contrasting hydro-sedimentary processes at work in both channels and bifurcation/confluence nodal points are analyzed from the measured flux distribution, morphological profiles and velocity and concentration patterns. In the cutoff, a diminishing of the intensity of the flow velocity (c. 50%) and of the SSC was observed correlated with the aggradation of the river bed. In the bifurcation/confluence nodal points and in the artificial canal were observed the most intensive hydrodynamic activity (high flow velocity, SSC concentration, degradation of the river bad). Both the event-scale and long-term morphological trends of the alluvial system are discussed analyzing the boundary shear stress and SSC variability. Excess boundary shear stress in the sub-reaches directly affected by cutoffs resulted in scour that increased downstream bed material load. These high sediment loads play a key role in driving morphological adjustments towards equilibrium in the cutoff channel. The approach followed in this paper combines detailed episodic in-situ aDcp measurements and robust numerical 1D modeling in order to provide a practical comprehension of the relevant morphodynamical processes. The 1D model reproduces robustly the continuity of hydrodynamical variables along the streamwise axes of the two-channel network. The simulated are used in the paper for highlighting reach-scale morphological processes, at both event and long-term scales.

Jugaru Tiron, Laura; Le Coz, Jérôme; Provansal, Mireille; Panin, Nicolae; Raccasi, Guillaume; Dramais, Guillaume; Dussouillez, Philippe

2009-05-01

402

Use of the GranuFlow Process in Coal Preparation Plants to Improve Energy Recovery and Reduce Coal Processing Wastes  

Energy Technology Data Exchange (ETDEWEB)

With the increasing use of screen-bowl centrifuges in today's fine coal cleaning circuits, a significant amount of low-ash, high-Btu coal can be lost during the dewatering step due to the difficulty in capturing coal of this size consist (< 100 mesh or 0.15mm). The GranuFlow{trademark} technology, developed and patented by an in-house research group at DOE-NETL, involves the addition of an emulsified mixture of high-molecular-weight hydrocarbons to a slurry of finesized coal before cleaning and/or mechanical dewatering. The binder selectively agglomerates the coal, but not the clays or other mineral matter. In practice, the binder is applied so as to contact the finest possible size fraction first (for example, froth flotation product) as agglomeration of this fraction produces the best result for a given concentration of binder. Increasing the size consist of the fine-sized coal stream reduces the loss of coal solids to the waste effluent streams from the screen bowl centrifuge circuit. In addition, the agglomerated coal dewaters better and is less dusty. The binder can also serve as a flotation conditioner and may provide freeze protection. The overall objective of the project is to generate all necessary information and data required to commercialize the GranuFlow{trademark} Technology. The technology was evaluated under full-scale operating conditions at three commercial coal preparation plants to determine operating performance and economics. The handling, storage, and combustion properties of the coal produced by this process were compared to untreated coal during a power plant combustion test.

Glenn A. Shirey; David J. Akers

2005-12-31

403

Summary of applications of TOUGH2 to the evaluation of multiphase flow processes at the WIPP  

International Nuclear Information System (INIS)

The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) research and development facility for the underground disposal of transuranic waste in southeastern New Mexico. The WIPP repository is located 655 m below the land surface in the lower portion of the Salado Formation, which is comprised of beds of pure and impure halite with thin interbeds of anhydrite and related clay seams. The regional dip of the Salado Formation is approximately 1 degree southeast in the vicinity of the repository. The proposed waste storage area has eight waste disposal panels, each of which will contain seven rooms. The repository is designed to follow a single stratigraphic horizon. Due to the dip, the north end of the repository will be about 10 meters higher than the south end. Waste that is emplaced in the disposal rooms will generate gas due to microbial degradation, anoxic corrosion, and radiolysis. Brine inflow to the rooms from the surrounding Salado Formation may significantly influence the gas generation rate and the total amount of gas generated. The salt surrounding the repository will creep in response to the excavation, reducing the room volume. Gas generation in the room may increase the pressure sufficiently to drive brine and gas into the surrounding Salado Formation. Migration of gas and brine in the Salado is an important factor in evaluating the performance of the repository. The studies summarized in this paper have. been performed to evaluate brine and gas flow processes in the WIPP disposal system and to identify some of the important processes. These studies are done in support of, but are not part of, the formal Performance Assessment (PA) effort. Because of probabilistic and system-scale requirements, the PA effort uses the Sandia-developed BRAGFLO (BRine And Gas FLOw) code for multiphase flow calculations

404

Modeling of reverse flow partial oxidation process for gasifier product gas upgrading  

Energy Technology Data Exchange (ETDEWEB)

Second generation biofuels use non-food crops such as agriculture waste and forest residue for the production of fuels. Biomass gasification is an important process for utilization of cellulose rich biomass. The gas produced in gasification contains carbon monoxide (CO), hydrogen (H{sub 2}), water (H{sub 2}O), carbon dioxide (CO{sub 2}), light hydrocarbons and tars. The light hydrocarbons can contain as much as 50 per cent of the total energy contents in the gas, depending on the type of gasifier, the operating conditions and the fuel. The gas also contains catalyst poisons such as sulfur, as hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS). This paper presented simulation work of a reverse flow partial oxidation reformer that reaches efficiencies approaching conventional catalytic processes. The study also investigated different reactor designs and parameter variations, such as pressure. Natural gas simulations were provided for comparative evaluations. They demonstrated the benefits of using reverse flow operation with lean gases such as gasifier product gas. 14 refs., 2 tabs., 7 figs.

Tuna, P.; Svensson, H.; Brandin, J. [Lund Univ., Lund (Sweden). Dept. of Chemical Engineering

2010-07-01

405

The diagram for phyllotactic series  

OpenAIRE

Many authors studying phyllotaxis in various plant species have reported the occurrence of many different numbers of contact parastichy pairs that are members of different Fibonacci-like series. On the basis of these reports a diagram was constructed in which any theoretically possible series was represented by the two first members of a given series.

Joanna Szymanowska-Pu?ka; Wies?aw W?och

1997-01-01

406

The diagram for phyllotactic series  

Directory of Open Access Journals (Sweden)

Full Text Available Many authors studying phyllotaxis in various plant species have reported the occurrence of many different numbers of contact parastichy pairs that are members of different Fibonacci-like series. On the basis of these reports a diagram was constructed in which any theoretically possible series was represented by the two first members of a given series.

Joanna Szymanowska-Pu?ka

1997-06-01

407

Algorithmic approach to diagram techniques  

International Nuclear Information System (INIS)

An algorithmic approach to diagram techniques of elementary particles is proposed. The definition and axiomatics of the theory of algorithms are presented, followed by the list of instructions of an algorithm formalizing the construction of graphs and the assignment of mathematical objects to them. (T.A.)

408

Trigeneration System: Visualization through Ternary Diagrams  

Directory of Open Access Journals (Sweden)

Full Text Available The simultaneous production of power, heat and refrigeration in trigeneration plants is potentially more efficient than producing these same utilities in separate facilities, mainly due to the increased opportunities for process integration. Hence, trigeneration is also inherently more cost-effective and thermodynamically efficient, resulting in lower CO2 footprint. Various methods have been developed for the synthesis of such plants. In this study, we propose a graphical approach where power, heat and refrigeration or cooling form the vertices of a ternary diagram. A thermal process unit may thus be represented as a point within the ternary diagram, with its coordinates denoting the ratios of its heat, power and cooling outputs. Thus, units producing two streams lie along the edges of the triangular field while those producing three streams fall inside it. Subsequently sizing of such process units that make up a trigeneration plant can be accomplished using lever-arm mixing rules within this triangular coordinate system. The use of the graphical methodology is illustrated with two case studies.

R.R. Tan

2014-01-01

409

The on-line graph processing study on phase separation of two-phase flow in T-tube  

International Nuclear Information System (INIS)

The on-line graph processing measure system is equipped with and experimental study of phase separation of air-water bubbly flow in the horizontal T-junction is carried out. For the first time, the author have found and defined the new type of complete phase separation, by the visual experiment, which shows that under certain conditions, the air flow entering the T junction will flow into the run outlet completely, which had never been reported in the literature Also, the pressure wave feed back effect and the branch bubble flow reorganization effect were found and analyzed. The complexity of this phase separation phenomenon in the T junction has been further revealed via the on-line graph processing technology. Meanwhile the influences of the inlet mass flow rate W1, the inlet mass quality X1, and the mass extraction rate G3/G1 on phase separation were analyzed

410

Preferential flow and mixing process in the chemical recharge in subsurface catchments: observations and modeling  

Science.gov (United States)

Shallow groundwater that develops on hillslopes is the main compartment in headwater catchments for flow and solute transport to rivers. Although spatial and temporal variations in its chemical composition are reported in the literature, there is no coherent description of the way these variations are organized, nor is there an accepted conceptual model for the recharge mechanisms and flows in the groundwater involved. We instrumented an intensive farming and subsurface dominant catchment located in Oceanic Western Europe (Kerbernez, Brittany, France), a headwater catchment included in the Observatory for Research on Environment AgrHyS (Agro-Hydro-System) and a part of the French Network of catchments for environmental research (SOERE RBV focused on the Critical Zone). These systems are strongly constrained by anthropogenic pressures (agriculture) and are characterized by a clear non-equilibrium status. A network of 42 nested piezometers was installed along a 200 m hillslope allowing water sampling along two transects in the permanent water table as well as in what we call the "fluctuating zone", characterized by seasonal alternance of saturated and unsaturated conditions. Water composition was monitored at high frequency (weekly) over a 3-year period for major anion composition and over a one year period for detailed 15N, CFC, SF6 and other dissolved gases. The results demonstrated that (i) the anionic composition in water table fluctuation zone varied significantly compared to deeper portions of the aquifer on the hillslope, confirming that this layer constitutes a main compartment for the mixing of new recharge water and old groundwater, (ii) seasonally, the variations of 15N and CFC are much higher during the recharge period than during the recession period, confirming the preferential flow during early recharge events, iii) variations of nitrate 15N and O18 composition was suggesting any significant denitrification process in the fluctuating zone, confirming the dominance of the mixing processes in the fluctuating zone, iv) deeper parts of the aquifer exhibited seasonal variations with structured hysteretic patterns, suggesting that mixing process also occurred at greater depths and v) these hysteretic patterns were dampered from upslope to downslope, indicating an increased influence of lateral flow downslope. A first modeling approach has been tested adding to a convection-dispersion model a mobile-immobile model, representing a mixing process between the pre-recharge water and the recharge water, and therefore taken into account the mixing processes varying from the surface to depth.As of now, we can deduce from these results that the residence times calculated from end member approaches considering the groundwater as homogeneous lumped reservoir are likely to be highly underestimated. We can also dedude that the water sampled in the shallow groundwater during the first part of the recharge period is chemically different from the water sampled after. Instrumented observatories including spatial and temporal monitoring of the hillslope groundwater are required to understand the anthropogenic and environmental processes and their interactions, to model and predict the effect and the response time of such systems under different constraints. This work is funded by AN-08-STRA-01 (National research Agency). Legout, C.; Molenat, J.; Aquilina, L.; Gascuel-Odoux, C.; Faucheux, M.; Fauvel, Y.; Bariac, T. 2007. Solute transfer in the unsaturated zone-groundwater continuum of a headwater catchment. Journal of Hydrology. 332 (2-4), 427-441. Rouxel, M., Molenat, J., Ruiz, L., Legout C., Faucheux, M., Gascuel-Odoux C., 2011. Seasonal and spatial variation in groundwater quality at the hillslope scale: study in an agricultural headwater catchment in Brittany (France). Hydrological Processes, 25, 831-841.

Gascuel-Odoux, C.; Rouxel, M.; Molenat, J.; Ruiz, L.; Aquilina, L.; Faucheux, M.; Labasque, T.; Sebilo, M.

2012-04-01

411

Assessment of Controlling Processes for Field-Scale Uranium Reactive Transport under Highly Transient Flow Conditions  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a comprehensive model-based analysis of a uranium tracer test conducted at the U.S Department of Energy Hanford 300 Area (300A) IFRC site. A three-dimensional multi-component reactive transport model was employed to assess the key factors and processes that control the field-scale uranium reactive transport. Taking into consideration of relevant physical and chemical processes, the selected conceptual/numerical model replicates the spatial and temporal variations of the observed U(VI) concentrations reasonably well in spite of the highly complex field conditions. A sensitivity analysis was performed to interrogate the relative importance of various processes and factors for reactive transport of U(VI) at the field-scale. The results indicate that multi-rate U(VI) sorption/desorption, U(VI) surface complexation reactions, and initial U(VI) concentrations were the most important processes and factors controlling U(VI) migration. On the other hand, cation exchange reactions, the choice of the surface complexation model, and dual-domain mass transfer processes, which were previously identified to be important in laboratory experiments, played less important roles under the field-scale experimental condition at the 300A site. However, the model simulations also revealed that the groundwater chemistry was relatively stable during the uranium tracer experiment and therefore presumably not dynamic enough to appropriately assess the effects of ion exchange reaction and the choice of surface complexation models on U(VI) sorption and desorption. Furthermore, it also showed that the field experimental duration (16 days) was not sufficiently long to precisely assess the role of a majority of the sorption sites that were accessed by slow kinetic processes within the dual domain model. The sensitivity analysis revealed the crucial role of the intraborehole flow that occurred within the long-screened monitoring wells and thus significantly affected both field-scale measurements and simulated U(VI) concentrations as a combined effect of aquifer heterogeneity and highly dynamic flow conditions. Overall, this study, which provides one of the few detailed and highly data-constrained uranium transport simulations, highlights the difference in controlling processes between laboratory and field scale that prevent a simple direct upscaling of laboratory-scale models.

Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John M.

2014-02-13

412

Basics of introduction to Feynman diagrams and electroweak interactions physics  

International Nuclear Information System (INIS)

The Feynman diagrams are the main computational method for the evaluation of the matrix elements of different processes. Although it is a perturbative method, its significance is not restricted to perturbation theory only. In this book, the elements of quantum field theory, the Feynman diagram method, the theory of electroweak interactions and other topics are discussed. A number of classical weak and electroweak processes are considered in details. This involves, first of all, the construction of the matrix elements of the process using both the Feynman diagram method (when perturbation theory can be applied) and the invariance principles (when perturbation theory fails). Then the cross sections and the decay probabilities are computed. The text is providing widely used computational techniques and some experimental data. (A.B.). 32 refs., 7 appendix

413

Nano-microscale models of periosteocytic flow show differences in stresses imparted to cell body and processes.  

Science.gov (United States)

In order to understand how local changes in mechanical environment are translated into cellular activity underlying tissue level bone adaptation, there is a need to explore fluid flow regimes at small scales such as the osteocyte. Recent developments in computational fluid dynamics (CFD) provide impetus to elucidate periosteocytic flow through development of a nanomicroscale model to study local effects of fluid flow on the osteocyte cell body, which contains the cellular organelles, and on the osteocyte processes, which connect the cell to the entire cellular network distributed throughout bone tissue. For each model, fluid flow was induced via a pressure gradient and the velocity profile and wall shear stress at the cell-fluid interface were calculated using a CFD software package designed for nano/micro-electromechanical-systems device development. Periosteocytic flow was modeled, taking into consideration the nanoscale dimensions of the annular channels and the flow pathways of the periosteocytic flow volume, to analyze the local effects of fluid flow on the osteocyte cell body (within the lacuna) and its processes (within the canaliculi). Based on the idealized model presented in this article, the osteocyte cell body is exposed primarily to effects of hydrodynamic pressure and the cell processes (CP) are exposed primarily to fluid shear stress, with highest stress gradients at sites where the process meets the cell body and where two CP link at the gap junction. Hence, this model simulates subcellular effects of fluid flow and suggests, for the first time to our knowledge, major differences in modes of loading between the domain of the cell body and that of the cell process. PMID:15709705

Anderson, Eric J; Kaliyamoorthy, Sathya; Iwan, J; Alexander, D; Knothe Tate, Melissa L

2005-01-01

414

Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes  

Science.gov (United States)

The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or calculated deliveries. IWFM utilizes a very straight-forward input file structure, allowing rapid development of complex simulations. A key feature of IWFM is a new algorithm for computation of groundwater flow across element faces. Enhancements to version 3.0 include automatic time-tracking of input and output data sets, linkage with the HEC-DSS database, and dynamic crop allocation using logit functions. Utilities linking IWFM to the PEST automated calibration suite are also available. All source code, executables and documentation are available for download from the DWR web site. IWFM is currently being used to develop hydrologic simulations of California's Central Valley (C2VSIM); the west side of California's San Joaquin Valley (WESTSIM); Butte County, CA; Solano County, CA; Merced County, CA; and the Oregon side of the Walla Walla River Basin.

Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

2006-12-01

415

Pilot results for a revolutionary cross-flow, fluid bed upgrading process  

Energy Technology Data Exchange (ETDEWEB)

The I{sup Y}Q Upgrading technology developed by Calgary-based ETX Systems Inc. merges 2 commercial technologies, notably cross flow fluid beds and thermal processing of heavy oil on fluid beds. The process has much lower commercialization risks than technologies based on more step-outs. ETX Systems conducted a pilot scale demonstration of its proprietary process as part of its commercialization strategy. A 1 bbl/d hot pilot plant was constructed in 2006 at the National Centre for Upgrading Technology in Devon, Alberta to verify the yield and quality claims of the I{sup Y}Q Upgrading technology. Although the results from the pilot project fully supported ETX's yield and quality claims, challenges were encountered with the pilot plant operation because of the small scale of the demonstration exercise. Through a targeted troubleshooting program, performance of the pilot unit was gradually increased to the point where it could accept pitch feed, as intended. This paper summarized the challenges encountered in the pilot program. To date, over 140 runs have been completed in the pilot unit. The pilot work supports the original claims regarding increased hydrogen retention in the product liquids, resulting in a significant environmental benefit through a reduction in upstream and downstream processing, thereby reducing intensities on a lifecycle basis. 4 refs., 2 tabs., 6 figs.

Lesage, B.; Monaghan, G.; Brown, W.A. [ETX Systems Inc., Calgary, AB (Canada)

2009-07-01

416

Effect of die shape on the metal flow pattern during direct extrusion process  

International Nuclear Information System (INIS)

The geometric shape of the tools is the main factor by which an optimum technological process can be developed. In the case of extrusion process the strain distribution and other important variables that influence material structure, such as hydrostatic stress, are strongly dependent on the geometry of the die. Careful design of the extrusion die profile can therefore control the product structure and can be used to minimise the amount of inhomogeneity imparted into the product. A possibility to minimise the amount of product inhomogeneity is the using of a flat die with a fillet radius in front to the bearing surface with leads to a minimum dead zone and consequently to a minimum friction at billet-container interface. In the case of aluminium alloy type 2024, for an extrusion ratio of R=8.5, good results were obtained with a fillet radius of 3.0 mm. The experimental data have been used for the finite element numerical simulation of the extrusion process. The data obtained by numerical simulation with FORGE2 programme confirm the theoretical and experimental outcomes. The aim of this paper is to study the influence of such flat die on the material flow during direct extrusion process and consequently on extruded product microstructure and mechanical properties. (Author).

417

Process development of Chemical etching and Diffusion Bonding for Helium Flow Channel  

International Nuclear Information System (INIS)

This research aimed at developing a wet chemical etching technique to machine the He flow channel of the process heat exchanger(PHE) made of Hastelloy X or equivalent high temperature high corrosion resistance material such as Alloy 617 and establishing an optimum diffusion bonding condition of these materials to assemble the PHE. The project is dealt with finding an optimum chemical etchant to develop about 0.5mm depth and 1.0 mm width on the surface of about 1.5mm thick Hastelloy-X sheet materials(or equivalents) and an process parameters for the diffusion bonding of the Hastelloy-X plates. Moderate performance results of etching process for high corrosion resistance material such as Alloy 617 was obtained. Namely, We could get the optimum chemical etchant to develop about 0.1?0.2mm depth and 1.0 mm width on the surface of about 1.5mm thick sheet materials. We could get a process parameters for the diffusion bonding of the Hastelloy X plates. Tensile strength test for diffusion bonded sample was performed and above eighty percent of original material strength was obtained

418

Step bunching process induced by the flow of steps at the sublimated crystal surface  

Science.gov (United States)

Stepped GaN(0001) surface is studied by the kinetic Monte Carlo method and compared with the model based on Burton-Cabrera-Frank equations. Successive stages of surface pattern evolution during high temperature sublimation process are discussed. At low sublimation rates, clear, well defined step bunches form. The process happens in the absence or for very low Schwoebel barriers. Bunches of several steps are well separated, move slowly and stay straight. Character of the process changes for more rapid sublimation process where double step formations become dominant and together with meanders and local bunches assemble into the less ordered surface pattern. Solution of the analytic equations written for one dimensional system confirms that step bunching is induced by the particle advection caused by step movement. Relative particle flow towards moving steps becomes important when due to the low Schwoebel barrier both sides of the step are symmetric. Simulations show that in the opposite limit of very high Schwoebel barrier steps fracture and rough surface builds up.

Za?uska-Kotur, Magdalena A.; Krzy?ewski, Filip

2012-06-01

419

Modeling gas-water processes in fractures with fracture flow properties obtained through upscaling  

Science.gov (United States)

Many environmental systems are driven by complex gas-water processes in fractured aquifers. One example is degassing processes occurring in fractures in the vicinity of radioactive waste disposal sites. These fractures can represent a potential fast track for radioactive substances to reach the surface: due to buoyancy effects, the created gas phase can move relatively quickly to the surface. The aim of this paper is to investigate and model the involved processes. First, a model for a single fracture is developed. Based on statistical properties of real fractures, an aperture distribution (raster element model) is created. A percolation-renormalization model yields effective properties, such as relative permeabilities and capillary pressure, and provides the size of a representative elementary volume. These effective relationships represent the basis for modeling the migration of the created gas phase through the fractured aquifer of the subsurface. An example modeling degassing and flow in a single fracture is shown and compared to experimental data. The presented model represents a conceptual method for degassing processes and the subsequent migration of the gas phase in fracture-matrix systems, improving predictions on the fate of radioactive substances.

Nuske, Philipp; Faigle, Benjamin; Helmig, Rainer; Niessner, Jennifer; Neuweiler, Insa

2010-09-01

420

Autoclave processing for composite material fabrication. 1: An analysis of resin flows and fiber compactions for thin laminate  

Science.gov (United States)

High quality long fiber reinforced composites, such as those used in aerospace and industrial applications, are c