WorldWideScience

Sample records for modeling net geochemical

  1. An interactive code (NETPATH) for modeling NET geochemical reactions along a flow PATH, version 2.0

    Science.gov (United States)

    Plummer, L. Niel; Prestemon, Eric C.; Parkhurst, David L.

    1994-01-01

    NETPATH is an interactive Fortran 77 computer program used to interpret net geochemical mass-balance reactions between an initial and final water along a hydrologic flow path. Alternatively, NETPATH computes the mixing proportions of two to five initial waters and net geochemical reactions that can account for the observed composition of a final water. The program utilizes previously defined chemical and isotopic data for waters from a hydrochemical system. For a set of mineral and (or) gas phases hypothesized to be the reactive phases in the system, NETPATH calculates the mass transfers in every possible combination of the selected phases that accounts for the observed changes in the selected chemical and (or) isotopic compositions observed along the flow path. The calculations are of use in interpreting geochemical reactions, mixing proportions, evaporation and (or) dilution of waters, and mineral mass transfer in the chemical and isotopic evolution of natural and environmental waters. Rayleigh distillation calculations are applied to each mass-balance model that satisfies the constraints to predict carbon, sulfur, nitrogen, and strontium isotopic compositions at the end point, including radiocarbon dating. DB is an interactive Fortran 77 computer program used to enter analytical data into NETPATH, and calculate the distribution of species in aqueous solution. This report describes the types of problems that can be solved, the methods used to solve problems, and the features available in the program to facilitate these solutions. Examples are presented to demonstrate most of the applications and features of NETPATH. The codes DB and NETPATH can be executed in the UNIX or DOS1 environment. This report replaces U.S. Geological Survey Water-Resources Investigations Report 91-4078, by Plummer and others, which described the original release of NETPATH, version 1.0 (dated December, 1991), and documents revisions and enhancements that are included in version 2.0. 1 The

  2. Geochemical modeling: a review

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A.

    1981-06-01

    Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

  3. Monitoring, field experiments, and geochemical modeling of Fe(II) oxidation kinetics in a stream dominated by net-alkaline coal-mine drainage, Pennsylvania, USA

    Science.gov (United States)

    Cravotta, Charles A.

    2015-01-01

    Watershed-scale monitoring, field aeration experiments, and geochemical equilibrium and kinetic modeling were conducted to evaluate interdependent changes in pH, dissolved CO2, O2, and Fe(II) concentrations that typically take place downstream of net-alkaline, circumneutral coal-mine drainage (CMD) outfalls and during aerobic treatment of such CMD. The kinetic modeling approach, using PHREEQC, accurately simulates observed variations in pH, Fe(II) oxidation, alkalinity consumption, and associated dissolved gas concentrations during transport downstream of the CMD outfalls (natural attenuation) and during 6-h batch aeration tests on the CMD using bubble diffusers (enhanced attenuation). The batch aeration experiments demonstrated that aeration promoted CO2 outgassing, thereby increasing pH and the rate of Fe(II) oxidation. The rate of Fe(II) oxidation was accurately estimated by the abiotic homogeneous oxidation rate law −d[Fe(II)]/dt = k1·[O2]·[H+]−2·[Fe(II)] that indicates an increase in pH by 1 unit at pH 5–8 and at constant dissolved O2 (DO) concentration results in a 100-fold increase in the rate of Fe(II) oxidation. Adjusting for sample temperature, a narrow range of values for the apparent homogeneous Fe(II) oxidation rate constant (k1′) of 0.5–1.7 times the reference value of k1 = 3 × 10−12 mol/L/min (for pH 5–8 and 20 °C), reported by Stumm and Morgan (1996), was indicated by the calibrated models for the 5-km stream reach below the CMD outfalls and the aerated CMD. The rates of CO2 outgassing and O2ingassing in the model were estimated with first-order asymptotic functions, whereby the driving force is the gradient of the dissolved gas concentration relative to equilibrium with the ambient atmosphere. Although the progressive increase in DO concentration to saturation could be accurately modeled as a kinetic function for the conditions evaluated, the simulation of DO as an instantaneous equilibrium process did not affect the

  4. Proceedings of the workshop on geochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices.

  5. Geochemical modelling baseline compositions of groundwater

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard;

    2008-01-01

    and variations in water chemistry that are caused by large scale geochemical processes taking place at the timescale of thousands of years. The most important geochemical processes are ion exchange (Valreas and Aveiro) where freshwater solutes are displacing marine ions from the sediment surface, and carbonate...... dissolution (East Midlands, Valreas and Aveiro). Reactive transport models, employing the code PHREEQC, which included these geochemical processes and one-dimensional solute transport were able to duplicate the observed patterns in water quality. These models may provide a quantitative understanding...

  6. Modelling Inteligent Systems with Level Petri Nets

    Directory of Open Access Journals (Sweden)

    Corina BOCĂNEALĂ

    2008-12-01

    Full Text Available Level Petri Nets are formalism for modeling hierarchical multi-agent system. They are a Petri nets extension, allowing tokens to be nets themselves. This paper is inspired by two classes of level Petri nets: object Petri nets and nested Petri nets. We present some concepts from the artificial intelligence field and we use them to illustrate the modeling power of Petri nets with multi levels.

  7. Modeling Low-temperature Geochemical Processes

    Science.gov (United States)

    Nordstrom, D. K.

    2003-12-01

    Geochemical modeling has become a popular and useful tool for a wide number of applications from research on the fundamental processes of water-rock interactions to regulatory requirements and decisions regarding permits for industrial and hazardous wastes. In low-temperature environments, generally thought of as those in the temperature range of 0-100 °C and close to atmospheric pressure (1 atm=1.01325 bar=101,325 Pa), complex hydrobiogeochemical reactions participate in an array of interconnected processes that affect us, and that, in turn, we affect. Understanding these complex processes often requires tools that are sufficiently sophisticated to portray multicomponent, multiphase chemical reactions yet transparent enough to reveal the main driving forces. Geochemical models are such tools. The major processes that they are required to model include mineral dissolution and precipitation; aqueous inorganic speciation and complexation; solute adsorption and desorption; ion exchange; oxidation-reduction; or redox; transformations; gas uptake or production; organic matter speciation and complexation; evaporation; dilution; water mixing; reaction during fluid flow; reaction involving biotic interactions; and photoreaction. These processes occur in rain, snow, fog, dry atmosphere, soils, bedrock weathering, streams, rivers, lakes, groundwaters, estuaries, brines, and diagenetic environments. Geochemical modeling attempts to understand the redistribution of elements and compounds, through anthropogenic and natural means, for a large range of scale from nanometer to global. "Aqueous geochemistry" and "environmental geochemistry" are often used interchangeably with "low-temperature geochemistry" to emphasize hydrologic or environmental objectives.Recognition of the strategy or philosophy behind the use of geochemical modeling is not often discussed or explicitly described. Plummer (1984, 1992) and Parkhurst and Plummer (1993) compare and contrast two approaches for

  8. Mechanisms and Geochemical Models of Core Formation

    CERN Document Server

    Rubie, David C

    2015-01-01

    The formation of the Earth's core is a consequence of planetary accretion and processes in the Earth's interior. The mechanical process of planetary differentiation is likely to occur in large, if not global, magma oceans created by the collisions of planetary embryos. Metal-silicate segregation in magma oceans occurs rapidly and efficiently unlike grain scale percolation according to laboratory experiments and calculations. Geochemical models of the core formation process as planetary accretion proceeds are becoming increasingly realistic. Single stage and continuous core formation models have evolved into multi-stage models that are couple to the output of dynamical models of the giant impact phase of planet formation. The models that are most successful in matching the chemical composition of the Earth's mantle, based on experimentally-derived element partition coefficients, show that the temperature and pressure of metal-silicate equilibration must increase as a function of time and mass accreted and so m...

  9. Modeling of economic systems with Petri nets

    Directory of Open Access Journals (Sweden)

    Pavel Valeryevich Skorodumov

    2014-09-01

    Full Text Available Modeling is one of the most important tools to study complex systems. Components of both continuous and discrete nature are present in the behavior of contemporary economic systems. The article uses formalism of nested hybrid Petri nets as a tool to study complex economic systems. The author describes basic approaches of simulation modelling, concepts of classical Petri nets, modified means of nested hybrid Petri nets, benefits of their use for systems modeling. The article presents the concept of a universal system of simulation modeling. On the basis of considered approaches the article proposes to develop a universal system of simulation modeling on the basis of the modified machine Petri nets

  10. Petri nets and other models of concurrency

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Sassone, Vladimiro

    1998-01-01

    This paper retraces, collects, and summarises contributions of the authors - in collaboration with others - on the theme of Petri nets and their categorical relationships to other models of concurrency.......This paper retraces, collects, and summarises contributions of the authors - in collaboration with others - on the theme of Petri nets and their categorical relationships to other models of concurrency....

  11. Geochemical modeling of magmatic gas scrubbing

    Directory of Open Access Journals (Sweden)

    B. Gambardella

    2005-06-01

    Full Text Available The EQ3/6 software package, version 7.2 was successfully used to model scrubbing of magmatic gas by pure water at 0.1 MPa, in the liquid and liquid-plus-gas regions. Some post-calculations were necessary to account for gas separation effects. In these post-calculations, redox potential was considered to be fixed by precipitation of crystalline a-sulfur, a ubiquitous and precocious process. As geochemical modeling is constrained by conservation of enthalpy upon water-gas mixing, the enthalpies of the gas species of interest were reviewed, adopting as reference state the liquid phase at the triple point. Our results confirm that significant emissions of highly acidic gas species (SO2(g, HCl(g, and HF(g are prevented by scrubbing, until dry conditions are established, at least locally. Nevertheless important outgassing of HCl(g can take place from acid, HCl-rich brines. Moreover, these findings support the rule of thumb which is generally used to distinguish SO2-, HCl-, and HF-bearing magmatic gases from SO2-, HCl-, and HF-free hydrothermal gases.

  12. The Aqueous Alteration of CR Chondrites: Experiments and Geochemical Modeling

    Science.gov (United States)

    Perronnet, M.; Berger, G.; Zolensky, M. E.; Toplis, M. J.; Kolb, V. M.; Bajagic, M.

    2007-03-01

    Laboratory alteration experiments were performed on mineralogical assemblages having the unaltered CR composition. The mineralogy of reaction products was compared to that of Renazzo and GRO 95577 and to predictions of geochemical modeling.

  13. Modeling and analysis using hybrid Petri nets

    CERN Document Server

    Ghomri, Latéfa

    2007-01-01

    This paper is devoted to the use of hybrid Petri nets (PNs) for modeling and control of hybrid dynamic systems (HDS). Modeling, analysis and control of HDS attract ever more of researchers' attention and several works have been devoted to these topics. We consider in this paper the extensions of the PN formalism (initially conceived for modeling and analysis of discrete event systems) in the direction of hybrid modeling. We present, first, the continuous PN models. These models are obtained from discrete PNs by the fluidification of the markings. They constitute the first steps in the extension of PNs toward hybrid modeling. Then, we present two hybrid PN models, which differ in the class of HDS they can deal with. The first one is used for deterministic HDS modeling, whereas the second one can deal with HDS with nondeterministic behavior. Keywords: Hybrid dynamic systems; D-elementary hybrid Petri nets; Hybrid automata; Controller synthesis

  14. Geochemical Modeling of ILAW Lysimeter Water Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-22

    Geochemical modeling results of water extracts from simulated immobilized low-activity waste (ILAW) glasses, placed in lysimeters for eight years suggest that the secondary phase reaction network developed using product consistency test (PCT) results at 90°C may need to be modified for field conditions. For sediment samples that had been collected from near the glass samples, the impact of glass corrosion could be readily observed based upon the pH of their water extracts. For unimpacted sediments the pH ranged from 7.88 to 8.11 with an average of 8.04. Sediments that had observable impacts from glass corrosion exhibited elevated pH values (as high as 9.97). For lysimeter sediment samples that appear to have been impacted by glass corrosion to the greatest extent, saturation indices determined for analcime, calcite, and chalcedony in the 1:1 water extracts were near equilibrium and were consistent with the secondary phase reaction network developed using PCT results at 90°C. Fe(OH)3(s) also appears to be essentially at equilibrium in extracts impacted by glass corrosion, but with a solubility product (log Ksp) that is approximately 2.13 units lower than that used in the secondary phase reaction network developed using PCT results at 90°C. The solubilities of TiO2(am) and ZrO2(am) also appear to be much lower than that assumed in the secondary phase reaction network developed using PCT results at 90°C. The extent that the solubility of TiO2(am) and ZrO2(am) were reduced relative to that assumed in the secondary phase reaction network developed using PCT results at 90°C could not be quantified because the concentrations of Ti and Zr in the extracts were below the estimated quantification limit. Gibbsite was consistently highly oversaturated in the extract while dawsonite was at or near equilibrium. This suggests that dawsonite might be a more suitable phase for the secondary phase reaction network

  15. Modeling workflow using XML and Petri net

    Institute of Scientific and Technical Information of China (English)

    杨东; 温泉; 张申生

    2004-01-01

    Nowadays an increasing number of workflow products and research prototypes begin to adopt XML for representing workflow models owing to its easy use and well understanding for people and machines. However, most of workflow products and research prototypes provide the few supports for the verification of XML-based workflow model, such as free-deadlock properties, which is essential to successful application of workflow technology. In this paper, we tackle this problem by mapping the XML-based workflow model into Petri-net, a kind of well-known formalism for modeling,analyzing and verifying system. As a result, the XML-based workflow model can be automatically verified with the help of general Petri-net tools, such as DANAMICS. The presented approach not only enables end users to represent workflow model with XML-based modeling language, but also the correctness of model can be ensured, thus satisfying the needs of business processes.

  16. This year`s model: Geochemical modeling and groundwater quality

    Energy Technology Data Exchange (ETDEWEB)

    Tuchfeld, H.A.; Simmons, S.P.; Jesionek, K.S. [GeoSyntec Consultants, Walnut Creek, CA (United States)]|[GeoSyntec Consultants, Atlanta, GA (United States); Romito, A.A. [Browning-Ferris Industries, Inc., Houston, TX (United States)

    1998-07-01

    It has been determined that landfill gas migration is a source of volatile organic compounds (VOCs) in groundwater. This can occur through: direct partitioning of migrating gas constituents into the groundwater; alteration of the physiochemical properties of the groundwater; and by indirect means (such as migration of landfill gas condensate and vadose zone water contaminated by landfill gas). This article examines the use of geochemical modeling as a useful tool for differentiating the effects of municipal solid waste (MSW) landfill gas versus leachate on groundwater quality at MSW landfill sites.

  17. Deep Belief Nets for Topic Modeling

    DEFF Research Database (Denmark)

    Maaløe, Lars; Arngren, Morten; Winther, Ole

    2015-01-01

    . Efficient retrieval can be carried out in the latent representation. We work both on public benchmarks and digital media content provided by Issuu, an on-line publishing platform. This article also comes with a newly developed deep belief nets toolbox for topic modeling tailored towards performance...

  18. Numerical modeling of geochemical variations caused by crustal relamination

    NARCIS (Netherlands)

    Vogt, Katharina; Castro, Antonio; Gerya, Taras

    2013-01-01

    Geochemical consequences of composite diapirs formed in subduction zones have been studied using a thermomechanical numerical model of an ocean-continent subduction zone. This model includes dehydration of subducted crust, aqueous fluid transport, partial melting, and melt emplacement. Subduction of

  19. Interactive Model Visualization for NET-VISA

    Science.gov (United States)

    Kuzma, H. A.; Arora, N. S.

    2013-12-01

    NET-VISA is a probabilistic system developed for seismic network processing of data measured on the International Monitoring System (IMS) of the Comprehensive nuclear Test Ban Treaty Organization (CTBTO). NET-VISA is composed of a Generative Model (GM) and an Inference Algorithm (IA). The GM is an explicit mathematical description of the relationships between various factors in seismic network analysis. Some of the relationships inside the GM are deterministic and some are statistical. Statistical relationships are described by probability distributions, the exact parameters of which (such as mean and standard deviation) are found by training NET-VISA using recent data. The IA uses the GM to evaluate the probability of various events and associations, searching for the seismic bulletin which has the highest overall probability and is consistent with a given set of measured arrivals. An Interactive Model Visualization tool (IMV) has been developed which makes 'peeking into' the GM simple and intuitive through a web-based interfaced. For example, it is now possible to access the probability distributions for attributes of events and arrivals such as the detection rate for each station for each of 14 phases. It also clarifies the assumptions and prior knowledge that are incorporated into NET-VISA's event determination. When NET-VISA is retrained, the IMV will be a visual tool for quality control both as a means of testing that the training has been accomplished correctly and that the IMS network has not changed unexpectedly. A preview of the IMV will be shown at this poster presentation. Homepage for the IMV IMV shows current model file and reference image.

  20. Validation of the WATEQ4 geochemical model for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.

    1983-09-01

    As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite (UO/sub 2/(OH)/sub 2/ . H/sub 2/O), UO/sub 2/(OH)/sub 2/, and rutherfordine ((UO/sub 2/CO/sub 3/) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions.

  1. Geochemical modeling of cyanide in tailing dam gold processing plant

    Science.gov (United States)

    Khodadadi, Ahmad; Monjezi, M.; Mehrpouya, H.; Dehghani, H.

    2009-09-01

    This research is aimed at investigating possible neutralization of cyanide in tailing dam of Muteh gold processing plant in Isfahan, Iran at various conditions such as pH and temperature using USEPA Visual MINTEQ geochemical model simulation. The model is based on geochemical equilibrium which uses the simultaneous solution of the non-linear mass action expressions and linear mass balance relationships to formulate and solve the multiple-component chemical equilibrium problems. In this study the concentration of aqueous species in tailing dam as an aqueous, solid and gaseous were used as input in the model. Temperature and pH variation were simulated. The results of the model indicated that cyanide may be complexes in 10 < pH < 5. In other pH values complexation is not important. The results also indicated that cyanide reduction mechanism in acidic pH and temperature above 30°C is due to cyanide acid formation which is vaporized.

  2. Adaptive Multiscale Modeling of Geochemical Impacts on Fracture Evolution

    Science.gov (United States)

    Molins, S.; Trebotich, D.; Steefel, C. I.; Deng, H.

    2016-12-01

    Understanding fracture evolution is essential for many subsurface energy applications, including subsurface storage, shale gas production, fracking, CO2 sequestration, and geothermal energy extraction. Geochemical processes in particular play a significant role in the evolution of fractures through dissolution-driven widening, fines migration, and/or fracture sealing due to precipitation. One obstacle to understanding and exploiting geochemical fracture evolution is that it is a multiscale process. However, current geochemical modeling of fractures cannot capture this multi-scale nature of geochemical and mechanical impacts on fracture evolution, and is limited to either a continuum or pore-scale representation. Conventional continuum-scale models treat fractures as preferential flow paths, with their permeability evolving as a function (often, a cubic law) of the fracture aperture. This approach has the limitation that it oversimplifies flow within the fracture in its omission of pore scale effects while also assuming well-mixed conditions. More recently, pore-scale models along with advanced characterization techniques have allowed for accurate simulations of flow and reactive transport within the pore space (Molins et al., 2014, 2015). However, these models, even with high performance computing, are currently limited in their ability to treat tractable domain sizes (Steefel et al., 2013). Thus, there is a critical need to develop an adaptive modeling capability that can account for separate properties and processes, emergent and otherwise, in the fracture and the rock matrix at different spatial scales. Here we present an adaptive modeling capability that treats geochemical impacts on fracture evolution within a single multiscale framework. Model development makes use of the high performance simulation capability, Chombo-Crunch, leveraged by high resolution characterization and experiments. The modeling framework is based on the adaptive capability in Chombo

  3. Geochemical modelling baseline compositions of groundwater

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard

    2008-01-01

    Reactive transport models, were developed to explore the evolution in groundwater chemistry along the flow path in three aquifers; the Triassic East Midland aquifer (UK), the Miocene aquifer at Valreas (F) and the Cretaceous aquifer near Aveiro (P). All three aquifers contain very old groundwaters...... of the evolution in natural baseline properties in groundwater....

  4. Greenhouse Modeling Using Continuous Timed Petri Nets

    Directory of Open Access Journals (Sweden)

    José Luis Tovany

    2013-01-01

    Full Text Available This paper presents a continuous timed Petri nets (ContPNs based greenhouse modeling methodology. The presented methodology is based on the definition of elementary ContPN modules which are designed to capture the components of a general energy and mass balance differential equation, like parts that are reducing or increasing variables, such as heat, CO2 concentration, and humidity. The semantics of ContPN is also extended in order to deal with variables depending on external greenhouse variables, such as solar radiation. Each external variable is represented by a place whose marking depends on an a priori known function, for instance, the solar radiation function of the greenhouse site, which can be obtained statistically. The modeling methodology is illustrated with a greenhouse modeling example.

  5. Model Checking Workflow Net Based on Petri Net

    Institute of Scientific and Technical Information of China (English)

    ZHOU Conghua; CHEN Zhenyu

    2006-01-01

    The soundness is a very important criterion for the correctness of the workflow.Specifying the soundness with Computation Tree Logic (CTL) allows us to verify the soundness with symbolic model checkers.Therefore the state explosion problem in verifying soundness can be overcome efficiently.When the property is not satisfied by the system,model checking can give a counter-example, which can guide us to correct the workflow.In addition, relaxed soundness is another important criterion for the workflow.We also prove that Computation Tree Logic * (CTL * ) can be used to character the relaxed soundness of the workflow.

  6. Modelling Knowledge Systems using Relation Nets and Hypernets

    OpenAIRE

    Rooyen, Hendrik O. van; Geldenhuys, Aletta E.; Stetter, Franz

    2004-01-01

    In the book "Knowledge Representation and Relation Nets" we introduced a structural model called a Relation Net and a special relation net called a Concept Relationship Knowledge Structure (CRKS). In this work we broaden the notion of a relation net to produce a new but associated structural model, a Hypernet. We show that the general theory of hypernets has applications in the acquisition/learning, representation, retrieval, accommodation and assimilation, management and communication/teachi...

  7. Access Nets: Modeling Access to Physical Spaces

    Science.gov (United States)

    Frohardt, Robert; Chang, Bor-Yuh Evan; Sankaranarayanan, Sriram

    Electronic, software-managed mechanisms using, for example, radio-frequency identification (RFID) cards, enable great flexibility in specifying access control policies to physical spaces. For example, access rights may vary based on time of day or could differ in normal versus emergency situations. With such fine-grained control, understanding and reasoning about what a policy permits becomes surprisingly difficult requiring knowledge of permission levels, spatial layout, and time. In this paper, we present a formal modeling framework, called AccessNets, suitable for describing a combination of access permissions, physical spaces, and temporal constraints. Furthermore, we provide evidence that model checking techniques are effective in reasoning about physical access control policies. We describe our results from a tool that uses reachability analysis to validate security policies.

  8. A New Geochemical Reaction Model for Groundwater Systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Through a survey of the literature on geology, hydrogeology and hydrogeochemistry, this paper presents a hydrogeochemical model for the groundwater system in a dross-dumping area of the Shandong Aluminium Plant. It is considered that the groundwater-bearing medium is a mineral aggregate and that the interactions between groundwater and the groundwater-bearing medium can be described as a series of geochemical reactions. On that basis, the principle of minimum energy and the equations of mass balance, electron balance and electric neutrality are applied to construct a linear programming mathematical model for the calculation of mass transfer between water and rock with the simplex method.

  9. Numerical modelling of new rockfall interception nets

    Science.gov (United States)

    von Boetticher, Albrecht; Volkwein, Axel; Wendeler, Corinna

    2010-05-01

    The design and certification of effective rockfall protection barriers is mainly achieved through 1:1 prototype testing. In order to reduce development costs of a prototype it is recommended that pre-studies using numerical simulations are performed. A large component to modelling rockfall protection systems is the numerical simulation of the nets. To date there exist several approaches to model the different mesh types such as ring nets or diagonal meshes (Nicot 1999, Cazzani et al. 2002, Volkwein 2004). However, the consideration of chain link meshes has not yet been realised. Chain link meshes are normally found as standard fence structures. However, they also exist in setups using high-strength steel and wire bundles. These variants show an enormous capacity to retain loads e.g. rockfalls, and at the same time are very efficient due to their low demand of steel material. The increasing application of chain link mesh in barrier systems requires an accurate model is available to complete prototype studies. A new approach now aims to perform a Finite Element simulation of such chain link meshes. The main challenge herein is to achieve the net deformation behaviour that is observed in field tests also in the simulation. A simulation using simple truss elements would not work since it neglects the out-of-plane-height of the mesh construction providing important reserves for local and global high deformations. Thus addressing this, a specially developed Discrete Element is able to reconstruct the mechanical behaviour of the single chain wire (bundles). As input parameters it utilises typical properties such as longitudinal and transversal mesh widths, and break loads resulting from in-plane-tension tests and steel strength. The single chain elements then can be combined to a complete mesh (e.g. 130 x 65 mm, 3 - 4 mm wire with a strength of 1770 N-mm2). Combining these elements with a supporting structure consisting of posts, ropes and energy absorbers, enables the

  10. MODELING MONOMETHYLMERCURY AND TRIBUTYLTIN SPECIATION WITH EPA'S GEOCHEMICAL SPECIATION MODEL MINTEQA2

    Science.gov (United States)

    Given the complexity of the various, simultaneous (and competing) equilibrium reactions governing the speciation of ionic species in aquatic systems, EPA has developed and distributed the geochemical speciation model MINTEQA2 (Brown and Allison, 1987, Allison et al., 1991; Hydrog...

  11. WATEQ3 geochemical model: thermodynamic data for several additional solids

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Jenne, E.A.

    1982-09-01

    Geochemical models such as WATEQ3 can be used to model the concentrations of water-soluble pollutants that may result from the disposal of nuclear waste and retorted oil shale. However, for a model to competently deal with these water-soluble pollutants, an adequate thermodynamic data base must be provided that includes elements identified as important in modeling these pollutants. To this end, several minerals and related solid phases were identified that were absent from the thermodynamic data base of WATEQ3. In this study, the thermodynamic data for the identified solids were compiled and selected from several published tabulations of thermodynamic data. For these solids, an accepted Gibbs free energy of formation, ..delta..G/sup 0//sub f,298/, was selected for each solid phase based on the recentness of the tabulated data and on considerations of internal consistency with respect to both the published tabulations and the existing data in WATEQ3. For those solids not included in these published tabulations, Gibbs free energies of formation were calculated from published solubility data (e.g., lepidocrocite), or were estimated (e.g., nontronite) using a free-energy summation method described by Mattigod and Sposito (1978). The accepted or estimated free energies were then combined with internally consistent, ancillary thermodynamic data to calculate equilibrium constants for the hydrolysis reactions of these minerals and related solid phases. Including these values in the WATEQ3 data base increased the competency of this geochemical model in applications associated with the disposal of nuclear waste and retorted oil shale. Additional minerals and related solid phases that need to be added to the solubility submodel will be identified as modeling applications continue in these two programs.

  12. A HYBRID PETRI-NET MODEL OF GRID WORKFLOW

    Institute of Scientific and Technical Information of China (English)

    Ji Yimu; Wang Ruchuan; Ren Xunyi

    2008-01-01

    In order to effectively control the random tasks submitted and executed in grid workflow, a grid workflow model based on hybrid petri-net is presented. This model is composed of random petri-net, colored petri-net and general petri-net. Therein random petri-net declares the relationship between the number of grid users' random tasks and the size of service window and computes the server intensity of grid system. Colored petri-net sets different color for places with grid services and provides the valid interfaces for grid resource allocation and task scheduling. The experiment indicated that the model presented in this letter could compute the valve between the number of users' random tasks and the size of grid service window in grid workflow management system.

  13. Transactions on Petri Nets and Other Models of Concurrency VI

    DEFF Research Database (Denmark)

    The sixth volume of ToPNoC includes revised versions of selected papers from workshops and tutorials held at the 32nd International Conference on Application and Theory of Petri Nets and Concurrency. It also contains a special section on Networks, Protocols, and Services, as well as a contributed...... paper submitted through the regular submission track of ToPNoC. The 14 papers cover a diverse range of topics including model checking and system verification, synthesis, foundational work on specific classes of Petri nets, and innovative applications of Petri nets and other models of concurrency. Thus...... this volume gives a good view of ongoing concurrent systems and Petri nets research....

  14. GEOCHEMICAL RECOGNITION OF SPILLED SEDIMENTS USED IN NUMERICAL MODEL VALIDATION

    Institute of Scientific and Technical Information of China (English)

    Jens R.VALEUR; Steen LOMHOLT; Christian KNUDSEN

    2004-01-01

    A fixed link (tunnel and bridge,in total 16 km) was constructed between Sweden and Denmark during 1995-2000.As part of the work,approximately 16 million tonnes of seabed materials (limestone and clay till) were dredged,and about 0.6 million tonnes of these were spilled in the water.Modelling of the spreading and sedimentation of the spilled sediments took place as part of the environmental monitoring of the construction activities.In order to verify the results of the numerical modelling of sediment spreading and sedimentation,a new method with the purpose of distinguishing between the spilled sediments and the naturally occurring sediments was developed.Because the spilled sediments tend to accumulate at the seabed in areas with natural sediments of the same size,it is difficult to separate these based purely on the physical properties.The new method is based on the geo-chemical differences between the natural sediment in the area and the spill.The basic properties used are the higher content of calcium carbonate material in the spill as compared to the natural sediments and the higher Ca/Sr ratio in the spill compared to shell fragments dominating the natural calcium carbonate deposition in the area.The reason for these differences is that carbonate derived from recent shell debris can be discriminated from Danien limestone,which is the material in which the majority of the dredging took place,on the basis of the Ca/Sr ratio being 488 in Danien Limestone and 237 in shell debris.The geochemical recognition of the origin of the sediments proved useful in separating the spilled from the naturally occurring sediments.Without this separation,validation of the modelling of accumulation of spilled sediments would not have been possible.The method has general validity and can be used in many situations where the origin ora given sediment is sought.

  15. Reactive surface area in geochemical models - Lessons learned from a natural analogue

    NARCIS (Netherlands)

    Koenen, M.; Wasch, L.J.

    2013-01-01

    Many uncertainties exist in geochemical modeling. Mineral reactive surface area is one of the uncertain parameters. QEMSCAN analyses are performed on sandstone samples from a Dutch CO2 natural analogue to determine reactive surface areas. Geochemical modeling is performed using QEMSCAN surface areas

  16. SpaceNet: Modeling and Simulating Space Logistics

    Science.gov (United States)

    Lee, Gene; Jordan, Elizabeth; Shishko, Robert; de Weck, Olivier; Armar, Nii; Siddiqi, Afreen

    2008-01-01

    This paper summarizes the current state of the art in interplanetary supply chain modeling and discusses SpaceNet as one particular method and tool to address space logistics modeling and simulation challenges. Fundamental upgrades to the interplanetary supply chain framework such as process groups, nested elements, and cargo sharing, enabled SpaceNet to model an integrated set of missions as a campaign. The capabilities and uses of SpaceNet are demonstrated by a step-by-step modeling and simulation of a lunar campaign.

  17. SpaceNet: Modeling and Simulating Space Logistics

    Science.gov (United States)

    Lee, Gene; Jordan, Elizabeth; Shishko, Robert; de Weck, Olivier; Armar, Nii; Siddiqi, Afreen

    2008-01-01

    This paper summarizes the current state of the art in interplanetary supply chain modeling and discusses SpaceNet as one particular method and tool to address space logistics modeling and simulation challenges. Fundamental upgrades to the interplanetary supply chain framework such as process groups, nested elements, and cargo sharing, enabled SpaceNet to model an integrated set of missions as a campaign. The capabilities and uses of SpaceNet are demonstrated by a step-by-step modeling and simulation of a lunar campaign.

  18. Transactions on Petri Nets and Other Models of Concurrency VII

    DEFF Research Database (Denmark)

    The first section is concerned with the creation of Petri net models and their validation The second section addresses semantic issues and analysis methods The third section is devoted to the automatic synthesis of Petri nets These Transactions publish archival papers in the broad area of Petri n...

  19. Modeling Background Radiation in our Environment Using Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas

    2015-02-01

    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  20. PNet: A Python Library for Petri Net Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Zhu En Chay

    2016-07-01

    Full Text Available Petri Net is a formalism to describe changes between 2 or more states across discrete time and has been used to model many systems. We present PNet – a pure Python library for Petri Net modeling and simulation in Python programming language. The design of PNet focuses on reducing the learning curve needed to define a Petri Net by using a text-based language rather than programming constructs to define transition rules. Complex transition rules can be refined as regular Python functions. To demonstrate the simplicity of PNet, we present 2 examples – bread baking, and epidemiological models.

  1. Geochemical controls on shale groundwaters: Results of reaction path modeling

    Energy Technology Data Exchange (ETDEWEB)

    Von Damm, K.L.; VandenBrook, A.J.

    1989-03-01

    The EQ3NR/EQ6 geochemical modeling code was used to simulate the reaction of several shale mineralogies with different groundwater compositions in order to elucidate changes that may occur in both the groundwater compositions, and rock mineralogies and compositions under conditions which may be encountered in a high-level radioactive waste repository. Shales with primarily illitic or smectitic compositions were the focus of this study. The reactions were run at the ambient temperatures of the groundwaters and to temperatures as high as 250/degree/C, the approximate temperature maximum expected in a repository. All modeling assumed that equilibrium was achieved and treated the rock and water assemblage as a closed system. Graphite was used as a proxy mineral for organic matter in the shales. The results show that the presence of even a very small amount of reducing mineral has a large influence on the redox state of the groundwaters, and that either pyrite or graphite provides essentially the same results, with slight differences in dissolved C, Fe and S concentrations. The thermodynamic data base is inadequate at the present time to fully evaluate the speciation of dissolved carbon, due to the paucity of thermodynamic data for organic compounds. In the illitic cases the groundwaters resulting from interaction at elevated temperatures are acid, while the smectitic cases remain alkaline, although the final equilibrium mineral assemblages are quite similar. 10 refs., 8 figs., 15 tabs.

  2. PETRI NET MODELING OF COMPUTER VIRUS LIFE CYCLE

    African Journals Online (AJOL)

    Dr Obe

    dynamic system analysis is applied to model the virus life cycle. Simulation of the .... of successful applications of Petri nets include distributed database systems, communication protocols, .... Concepts and Design". McGraw-Hill Computer.

  3. Comparison of the performance of net radiation calculation models

    DEFF Research Database (Denmark)

    Kjærsgaard, Jeppe Hvelplund; Cuenca, R H; Martinez-Cob, A

    2009-01-01

    values of net radiation were calculated using three net outgoing long-wave radiation models and compared to measured values. Four meteorological datasets representing two climate regimes, a sub-humid, high-latitude environment and a semi-arid mid-latitude environment, were used to test the models...... meteorological input data is limited. Model predictions were found to have a higher bias and scatter when using summed calculated hourly time steps compared to using daily input data.......Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily...

  4. Data Sources for NetZero Ft Carson Model

    Data.gov (United States)

    U.S. Environmental Protection Agency — Table of values used to parameterize and evaluate the Ft Carson NetZero integrated Model with published reference sources for each value. This dataset is associated...

  5. Precipitation of heavy metals from acid mine drainage and their geochemical modeling

    Science.gov (United States)

    Petrilakova, Aneta; Balintova, Magdalena; Holub, Marian

    2014-06-01

    Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia) with the results obtained by geochemical modeling software Visual Minteq 3.0.

  6. Precipitation of heavy metals from acid mine drainage and their geochemical modeling

    Directory of Open Access Journals (Sweden)

    Petrilakova Aneta

    2014-06-01

    Full Text Available Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD. AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia with the results obtained by geochemical modeling software Visual Minteq 3.0.

  7. Aquifer Storage and Recovery : Physical and Geochemical Modelling (SWIFTPHREEQC)of British Aquifers for Aquifer Storage and Recovery Purposes. Part 1, physical modelling and geochemical model calibration

    OpenAIRE

    2000-01-01

    This report describes the progress that has been made in developing models simulating both the physical and geochemical aspects of Aquifer Storage Recovery (ASR) schemes. This work is part of a 30 month project, entitled ASR-UK, which started in April 1999. The report describes progress to the end of 1999. SWIFT is a fully transient 3-Dimensional model that simulates flow and transport of fluids. It is ideally suited to modelling ASR and has been used to simulate the response o...

  8. Resolving the Multi-scale Behavior of Geochemical Weathering in the Critical Zone Using High Resolution Hydro-geochemical Models

    Science.gov (United States)

    Pandey, S.; Rajaram, H.

    2015-12-01

    This work investigates hydrologic and geochemical interactions in the Critical Zone (CZ) using high-resolution reactive transport modeling. Reactive transport models can be used to predict the response of geochemical weathering and solute fluxes in the CZ to changes in a dynamic environment, such as those pertaining to human activities and climate change in recent years. The scales of hydrology and geochemistry in the CZ range from days to eons in time and centimeters to kilometers in space. Here, we present results of a multi-dimensional, multi-scale hydro-geochemical model to investigate the role of subsurface heterogeneity on the formation of mineral weathering fronts in the CZ, which requires consideration of many of these spatio-temporal scales. The model is implemented using the reactive transport code PFLOTRAN, an open source subsurface flow and reactive transport code that utilizes parallelization over multiple processing nodes and provides a strong framework for simulating weathering in the CZ. The model is set up to simulate weathering dynamics in the mountainous catchments representative of the Colorado Front Range. Model parameters were constrained based on hydrologic, geochemical, and geophysical observations from the Boulder Creek Critical Zone Observatory (BcCZO). Simulations were performed in fractured rock systems and compared with systems of heterogeneous and homogeneous permeability fields. Tracer simulations revealed that the mean residence time of solutes was drastically accelerated as fracture density increased. In simulations that include mineral reactions, distinct signatures of transport limitations on weathering arose when discrete flow paths were included. This transport limitation was related to both advective and diffusive processes in the highly heterogeneous systems (i.e. fractured media and correlated random permeability fields with σlnk > 3). The well-known time-dependence of mineral weathering rates was found to be the most

  9. Geochemical Modeling of Carbon Sequestration, MMV, and EOR in the Illinois Basin

    Science.gov (United States)

    Berger, P.M.; Roy, W.R.; Mehnert, E.

    2009-01-01

    The Illinois State Geologic Survey is conducting several ongoing CO2 sequestration projects that require geochemical models to gain an understanding of the processes occurring in the subsurface. The ISGS has collected brine and freshwater samples associated with an enhanced oil recovery project in the Loudon oil field. Geochemical modeling allows us to understand reactions with carbonate and silicate minerals in the reservoir, and the effects they have had on brine composition. For the Illinois Basin Decatur project, geochemical models should allow predictions of the reactions that will take place before CO2 injection begins. ?? 2009 Elsevier Ltd. All rights reserved.

  10. GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Millings, M.; Denham, M.; Looney, B.

    2012-05-08

    From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors

  11. Precipitation of heavy metals from acid mine drainage and their geochemical modeling

    OpenAIRE

    Petrilakova Aneta; Balintova Magdalena; Holub Marian

    2014-01-01

    Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results o...

  12. A geochemical model of the Platanares geothermal system, Honduras

    Science.gov (United States)

    Janik, C.J.; Truesdell, A.H.; Goff, F.; Shevenell, L.; Stallard, M.L.; Trujillo, P.E.; Counce, D.

    1991-01-01

    Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three coreholes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at 450 to 680 m depth. Large volume artesian flows of 160-165??C, predominantly bicarbonate water are chemically similar to, but slightly less saline than widespread boiling hot-spring waters. The chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells. Chemical, isotope, and gas geothermometers indicate a deep fluid temperature of 200-245??C and reflect a relatively short residence time in the fractures feeding the wells. Chloride-enthalpy relations as well as isotopic and chemical compositions of well discharges, thermal springs, and local cold waters support a conceptual model of ascending high-temperature (minimum 225??C) parent fluid that has cooled conductively to form the 160-165??C shallow (to 680 m) fluid encountered by the wells. The hot-spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid. The more dilute boiling spring waters (Cl = ???32 mg/kg) have cooled from > 225??C to about 160??C by conduction and from 160??C to 98??C by boiling. The most concentrated boiling spring waters (Cl = 37 mg/kg) have cooled from > 225??C to about 200??C by conduction and from 200??C to 98??C by boiling. Intermediate concentrations reflect mixed cooling paths. ?? 1991.

  13. Fluid Survival Tool: A Model Checker for Hybrid Petri Nets

    NARCIS (Netherlands)

    Postema, Björn; Remke, Anne; Haverkort, Boudewijn R.; Ghasemieh, Hamed

    2014-01-01

    Recently, algorithms for model checking Stochastic Time Logic (STL) on Hybrid Petri nets with a single general one-shot transition (HPNG) have been introduced. This paper presents a tool for model checking HPNG models against STL formulas. A graphical user interface (GUI) not only helps to demonstra

  14. Modelling geochemical and microbial consumption of dissolved oxygen after backfilling a high level radiactive waste repository.

    Science.gov (United States)

    Yang, Changbing; Samper, Javier; Molinero, Jorge; Bonilla, Mercedes

    2007-08-15

    Dissolved oxygen (DO) left in the voids of buffer and backfill materials of a deep geological high level radioactive waste (HLW) repository could cause canister corrosion. Available data from laboratory and in situ experiments indicate that microbes play a substantial role in controlling redox conditions near a HLW repository. This paper presents the application of a coupled hydro-bio-geochemical model to evaluate geochemical and microbial consumption of DO in bentonite porewater after backfilling of a HLW repository designed according to the Swedish reference concept. In addition to geochemical reactions, the model accounts for dissolved organic carbon (DOC) respiration and methane oxidation. Parameters for microbial processes were derived from calibration of the REX in situ experiment carried out at the Aspö underground laboratory. The role of geochemical and microbial processes in consuming DO is evaluated for several scenarios. Numerical results show that both geochemical and microbial processes are relevant for DO consumption. However, the time needed to consume the DO trapped in the bentonite buffer decreases dramatically from several hundreds of years when only geochemical processes are considered to a few weeks when both geochemical reactions and microbially-mediated DOC respiration and methane oxidation are taken into account simultaneously.

  15. A framework for quantifying net benefits of alternative prognostic models

    DEFF Research Database (Denmark)

    Rapsomaniki, Eleni; White, Ian R; Wood, Angela M

    2012-01-01

    New prognostic models are traditionally evaluated using measures of discrimination and risk reclassification, but these do not take full account of the clinical and health economic context. We propose a framework for comparing prognostic models by quantifying the public health impact (net benefit...

  16. A framework for quantifying net benefits of alternative prognostic models

    NARCIS (Netherlands)

    Rapsomaniki, Eleni; White, Ian R.; Wood, Angela M.; Thompson, Simon G.

    2012-01-01

    New prognostic models are traditionally evaluated using measures of discrimination and risk reclassification, but these do not take full account of the clinical and health economic context. We propose a framework for comparing prognostic models by quantifying the public health impact (net benefit) o

  17. Possibilistic Fuzzy Net Present Value Model and Application

    Directory of Open Access Journals (Sweden)

    S. S. Appadoo

    2014-01-01

    Full Text Available The cash flow values and the interest rate in the net present value (NPV model are usually specified by either crisp numbers or random variables. In this paper, we first discuss some of the recent developments in possibility theory and find closed form expressions for fuzzy possibilistic net present value (FNPV. Then, following Carlsson and Fullér (2001, we discuss some of the possibilistic moments related to FNPV model along with an illustrative numerical example. We also give a unified approach to find higher order moments of FNPV by using the moment generating function introduced by Paseka et al. (2011.

  18. Petri nets extension to model state-varying failure rates

    DEFF Research Database (Denmark)

    Lazarova-Molnar, Sanja

    2013-01-01

    One of the most common assumptions in reliability modeling is the constant failure rate. This has been increasingly changing lately, yielding significant research towards abandoning simulation results based on this assumption; thus, deeming constant failure rates as inadequate to model failures......-varying failure rates and extend the formalism of Petri nets to model them. To illustrate our approach we provide an example model that features state-varying failure rates....

  19. Modeling humanoid swarm robots with petri nets

    OpenAIRE

    2015-01-01

    Robots have become a hot topic in today‟s electronic world. There are many definitions for it. One of the definition in Oxford dictionary states “a robot is a machine capable for carrying out a complex series of action automatically especially one programmable by a computer”. This paper deals with a special kind of robot, which is also known as humanoid robot. These robots are replication of human beings with head, torso, arms and legs. A model of human is presented in this paper as discre...

  20. Dynamic properties of fuzzy Petri net model and related analysis

    Institute of Scientific and Technical Information of China (English)

    周恺卿; Azlan Mohd Zain; 莫礼平

    2015-01-01

    Fuzzy Petri net (FPN) has been extensively applied in industrial fields for knowledge-based systems or systems with uncertainty. Although the applications of FPN are known to be successful, the theoretical research of FPN is still at an initial stage. To pave a way for further study, this work explores related dynamic properties of FPN including reachability, boundedness, safeness, liveness and fairness. The whole methodology is divided into two phases. In the first phase, a comparison between elementary net system (EN_system) and FPN is established to prove that the FPN is an extensive formalism of Petri nets using a backwards-compatible extension method. Next, current research results of dynamic properties are utilized to analyze FPN model. The results illustrate that FPN model is bounded, safe, weak live and fair, and can support theoretical evidences for designing related decomposition algorithm.

  1. Geochemical characteristics of the Permian basins and their provenances across the Solonker Suture Zone: Assessment of net crustal growth during the closure of the Palaeo-Asian Ocean

    Science.gov (United States)

    Eizenhöfer, Paul R.; Zhao, Guochun; Zhang, Jian; Han, Yigui; Hou, Wenzhu; Liu, Dongxing; Wang, Bo

    2015-05-01

    The Solonker Suture Zone is commonly recognised as the location of the Late Permian to Early Triassic closure of the Palaeo-Asian Ocean in the southeastern segment of the Central Asian Orogenic Belt. However, the absence of typical suture-related features, as a consequence of uncommon collisional geometries, gave it a cryptic nature. Thus, the tectonic setting, which led to suturing, still remains enigmatic. A geochemical characterisation of Permian sedimentary and volcanic rocks across the suture was carried out. Supplemented with Hf and Nd isotopic analyses, this approach enables not only a better definition of such regional suture, but also estimates on the long-controversial issue of net crustal growth in accretionary tectonic environments. The results indicate short sedimentary transport distances between the arc basins and their provenances, of which the studied volcanic rocks were a major contributor. Similar enrichment and depletion patterns with respect to N-MORB and average continental crust further corroborate a close source-sediment relationship. Immobile element provenance analyses indicate that the active continental northern margin of the North China Craton was a major source for arc basins to the south of the Solonker Suture Zone. To its north, arc basins are interpreted to be sourced by a more complex mixture of provenances, e.g., the Baolidao volcanic arc suite and the heterogenous Precambrian basement of southern Mongolia. An overall collisional tectonic setting across the suture is recognised. The geochemical signature of sedimentary rocks to the south of the suture points at an active continental arc setting, whereas the bimodal geochemical distribution of the samples to the north shows a contemporaneous active oceanic island arc as well as a passive margin environment. These features favour a double-sided subduction of the Palaeo-Asian Ocean beneath the North China Craton and the Mongolian Arcs throughout the Palaeozoic, including back

  2. Risk evaluation of uranium mining: A geochemical inverse modelling approach

    Science.gov (United States)

    Rillard, J.; Zuddas, P.; Scislewski, A.

    2011-12-01

    It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the

  3. Finite petri nets as models for recursive causal behaviour

    NARCIS (Netherlands)

    Goltz, Ursula; Rensink, Arend

    1994-01-01

    Goltz (1988) discussed whether or not there exist finite Petri nets (with unbounded capacities) modelling the causal behaviour of certain recursive CCS terms. As a representative example, the following term is considered: B=(a.nil | b.B)+c.nil. We will show that the answer depends on the chosen

  4. Modelling, design, and optimization of net-zero energy buildings

    CERN Document Server

    Athienitis, Andreas

    2015-01-01

    Building energy design is currently going through a period of major changes. One key factor of this is the adoption of net-zero energy as a long term goal for new buildings in most developed countries. To achieve this goal a lot of research is needed to accumulate knowledge and to utilize it in practical applications. In this book, accomplished international experts present advanced modeling techniques as well as in-depth case studies in order to aid designers in optimally using simulation tools for net-zero energy building design. The strategies and technologies discussed in this book are, ho

  5. Petri net model for analysis of concurrently processed complex algorithms

    Science.gov (United States)

    Stoughton, John W.; Mielke, Roland R.

    1986-01-01

    This paper presents a Petri-net model suitable for analyzing the concurrent processing of computationally complex algorithms. The decomposed operations are to be processed in a multiple processor, data driven architecture. Of particular interest is the application of the model to both the description of the data/control flow of a particular algorithm, and to the general specification of the data driven architecture. A candidate architecture is also presented.

  6. Delayed geochemical hazard: Concept, digital model and case study

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming; FENG Liu; Jacques Yvon

    2005-01-01

    Delayed Geochemical Hazard (DGH briefly) presents the whole process of a kind of serious ecological and environmental hazard caused by sudden reactivation and sharp release of long-term accumulated pollutant from stable species to active ones in soil or sediment system due to the change of physical-chemical conditions (such as temperature, pH, Eh, moisture, the concentrations of organic matters, etc.) or the decrease of environment capacity. The characteristics of DGH are discussed. The process of a typical DGH can be expressed as a nonlinear polynomial. The points where the derivative functions of the first and second orders of the polynomial reach zero, minimum and maximum are keys for risk assessment and harzard pridication.The process and mechanism of the hazard is due to the transform of pollutant among different species principally. The concepts of "total releasable content of pollutant", TRCP, and "total concentration of active specie", TCAS, are necessarily defined to describe the mechanism of DGH. The possibility of the temporal and spatial propagation is discussed. Case study shows that there exists a transform mechanism of "gradual release" and "chain reaction" among the species of the exchangeable and the bounds to carbonate, iron and manganese oxides and organic matter, thus causing the delayed geochemical hazard.

  7. Petri net based modeling and analysis for weldingflexible manufacturing cell

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Due to the development of advanced manufacturing technology and the introduction of Smart-Manufacturing notion in the field of modern industrial production, welding flexible manufacturing using robot technology has become the inevitable developing direction on welding automation. Based on a new intelligent arc-welding flexible manufacturing cell (WFMC), its system structure and control policies are studied in this paper. Aiming at the different information flows among every subsystem and central monitoring computer in this WFMC, Petri net theory is introduced into the process of welding manufacturing. A discrete control model of WFMC has been constructed, in which the system’s status is regarded as place and the control process is regarded as transition. Moreover, grounded on automation Petri net principle, the judging and utilizing of information obtained from welding sensors are imported into Petri net structure, which extends the traditional Petri net concepts. The control model and policies researched in this paper have established foundation for further intelligent real-time control on welding flexible manufacturing cell and system.

  8. Perti Net-Based Workflow Access Control Model

    Institute of Scientific and Technical Information of China (English)

    陈卓; 骆婷; 石磊; 洪帆

    2004-01-01

    Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current access control models. The model supports roles assignment and dynamic authorization. The paper defines the workflow using Petri net. It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM). Finally, an example of an e-commerce workflow access control model is discussed in detail.

  9. Coarse graining methods for spin net and spin foam models

    CERN Document Server

    Dittrich, Bianca; Martin-Benito, Mercedes

    2011-01-01

    We undertake first steps in making a class of discrete models of quantum gravity, spin foams, accessible to a large scale analysis by numerical and computational methods. In particular, we apply Migdal-Kadanoff and Tensor Network Renormalization schemes to spin net and spin foam models based on finite Abelian groups and introduce `cutoff models' to probe the fate of gauge symmetries under various such approximated renormalization group flows. For the Tensor Network Renormalization analysis, a new Gauss constraint preserving algorithm is introduced to improve numerical stability and aid physical interpretation. We also describe the fixed point structure and establish an equivalence of certain models.

  10. A Network Attack Model based on Colored Petri Net

    Directory of Open Access Journals (Sweden)

    Xinlei Li

    2014-07-01

    Full Text Available The researches have shown that not all the Petri Net machines can be used to describe attack behavior. When Petri Net machines adapted for attack behavior modeling are detecting the network, for some event of current status, if there is matching event in the model, it has only one corresponding transition; otherwise that may cause errors. Since sharing synthesis and synchronization synthesis of traditional machines cannot ensure synthetic model reserves original detection capability, we propose the novel concept for synthesis operation and colored synthetic operation. By the analysis on the relation among these operations, the ability to reserve original detection is verified. Then an improved colored judgement Petri Net machine is adopted for modeling and renewing the knowledge repository. The inductive learning method is used to extend the attack modes. It creates a four-layered concept space, which actually provides a depth-first search path for matching. To solve the problems in multi-pattern matching and incremental learning, various modes are generalized by colored operation. We also adopt the decomposition and synthesis operation to handle the pattern matching of distributed attack behavior and attack information fusion. Finally the actual cases verify that our algorithm is feasible

  11. An Attack Modeling Based on Colored Petri Net

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shijie; QIN Zhiguang; ZHANG Feng; LIU Jinde

    2004-01-01

    A color petri net (CPN) based attack modeling approach is addressed.Compared with graph-based modeling,CPN based attack model is fiexible enough to model Intemet intrusions,because of their static and dynamic features.The processes and rules of building CPN based attack model from attack tree are also presented.In order to evaluate the risk of intrusion,some cost elements are added to CPN based attack modeling.This extended model is useful in intrusion detection and risk evaluation.Experiences show that it is easy to exploit CPN based attack modeling approach to provide the controlling functions,such as intrusion response and intrusion defense.A case study given in this paper shows that CPN based attack model has many unique characters which attack tree model hasn't.

  12. Modeling of Testability Requirement Based on Generalized Stochastic Petri Nets

    Institute of Scientific and Technical Information of China (English)

    SU Yong-ding; QIU Jing; LIU Guan-jun; QIAN Yan-ling

    2009-01-01

    Testability design is an effective way to realize the fault detection and isolation. Its important step is to determine testability figures of merits (TFOM). Firstly, some influence factors for TFOMs are analyzed, such as the processes of system operation, maintenance and support, fault detection and isolation and so on. Secondly, a testability requirement analysis model is built based on generalized stochastic Petri net (GSPN). Then, the system's reachable states are analyzed based on the model, a Markov chain isomorphic with Petri net is constructed, a state transition matrix is created and the system's steady state probability is obtained. The relationship between the steady state availability and testability parameters can be revealed and reasoned. Finally, an example shows that the proposed method can determine TFOM, such as fault detection rate and fault isolation rate, effectively and reasonably.

  13. Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

    Energy Technology Data Exchange (ETDEWEB)

    Viani, B.E.; Bruton, C.J.

    1992-06-01

    Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs or Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites.

  14. Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

    Energy Technology Data Exchange (ETDEWEB)

    Viani, B.E.; Bruton, C.J. [Lawrence Livermore National Lab., CA (United States)

    1992-12-31

    Potential disposal of high-level nuclear waste at Yucca Mtn., Nevada requires the means to simulate ion-exchange behavior of clays and zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs and Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites. 15 refs., 5 figs., 1 tab.

  15. Interactive Multimedia Synchronization Model Based on Petri Nets

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiqiang; PENG Xiaogang; JI Zhen

    2007-01-01

    The multimedia synchronization is used to coordinate the timing of each multimedia object in the multimedia system.After studying different multimedia synchronization systems that have been published, an Interactive Synchronization multimedia based on Petri Nets model (ISPN) is proposed in this paper. The system is capable of describing the dynamic timing actions of multimedia objects vividly as well as controlling them interactively to maintain the system level synchronization balance.

  16. Experiments and geochemical modelling of CO{sub 2} sequestration by olivine: Potential, quantification

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, B., E-mail: Bruno.Garcia@ifp.fr [Institut Francais du Petrole, 1 et 4 Avenue du Bois Preau, 92852 Rueil Malmaison (France); Beaumont, V.; Perfetti, E.; Rouchon, V.; Blanchet, D. [Institut Francais du Petrole, 1 et 4 Avenue du Bois Preau, 92852 Rueil Malmaison (France); Oger, P.; Dromart, G. [Universite de Lyon, CNRS, UMR 5570, ENS de Lyon, Site Monod, 15 Parvis Rene Descartes BP 7000, Lyon F-69342 (France); Huc, A.-Y.; Haeseler, F. [Institut Francais du Petrole, 1 et 4 Avenue du Bois Preau, 92852 Rueil Malmaison (France)

    2010-09-15

    Aqueous solutions equilibrated with supercritical CO{sub 2} (150 deg. C and total pressure of 150 bar) were investigated in order to characterize their respective conditions of carbonation. Dissolution of olivine and subsequent precipitation of magnesite with a net consumption of CO{sub 2} were expected. A quantified pure mineral phase (powders with different olivine grain diameter [20-80 {mu}m], [80-125 {mu}m], [125-200 {mu}m] and [>200 {mu}m]), and CO{sub 2} (as dried ice) were placed in closed-batch reactors (soft Au tubes) in the presence of solutions. Different salinities (from 0 to 3400 mM) and different ratios of solution/solid (mineral phase) (from 0.1 to 10) were investigated. Experiments were performed over periods from 2 to 8 weeks. Final solid products were quantified by the Rock-Eval 6 technique, and identified using X-ray diffraction, Raman spectroscopy, electron microprobe and scanning electron microscopy. Gaseous compounds were quantified by a vacuum line equipped with a Toepler pump and identified and measured by gas chromatography (GC). Carbon mass balances were calculated. Olivine reacted completely with CO{sub 2}, trapping up to 57 {+-} 2% (eqC of initial CO{sub 2}) as magnesite; some amorphous silica also formed. Olivine grain diameter and solution/mineral ratios appeared to be the primary controls on the reaction, salinity acting as a second order parameter. During the experiments, fluid analyses may not be performed with approach adopted but, geochemical modelling was attempted to give information about the solution composition. This showed an interesting mineral matrix evolution. Under the experimental conditions, olivine appeared to be a good candidate for CO{sub 2} trapping into a geologically stable carbonate, magnesite. The possible use of mafic and ultramafic rocks for CO{sub 2} sequestration is discussed.

  17. Cumulants of Net-Proton, Net-Kaon and Net-Charge Multiplicity Distributions in Au+Au Collisions at RHIC BES Energies from UrQMD Model

    CERN Document Server

    Xu, Ji; Liu, Feng; Luo, Xiaofeng

    2016-01-01

    Fluctuations of conserved quantities are sensitive observables to probe the signature of QCD phase transition and critical point in heavy-ion collisions. With the UrQMD model, we have studied the centrality and energy dependence of various order cumulants and cumulant ratios (up to fourth order) of net-proton,net-charge and net-kaon multiplicity distributions in Au+Au collisions at $\\sqrt{s_{NN}}$= 7.7, 11.5, 19.6, 27, 39, 62.4, 200 GeV. The model results show that the production mechanism of the particles and anti-particles have significant impacts on the cumulants of net-particles multiplicity distributions and show strong energy dependence. We also made comparisons between model calculations and experimental data measured in the first phase of the beam energy scan (BES) program by the STAR experiment at RHIC. The comparisons indicate that the baryon conservation effect strongly suppress the cumulants of net-proton distributions at low energies and the non-monotonic energy dependence for the net-proton {\\KV...

  18. Spatial analysis and modelling of glaciogenic geochemical dispersion - Implication for mineral exploration in Finland

    Science.gov (United States)

    Sarala, Pertti; Nykänen, Vesa

    2017-04-01

    Spatial modelling for prospectivity mapping involves the integration of various geoscientific digital map data. It is essential that the quality of data is high class and that the geological processes involved are well understood. Effects of glacial dynamics and glaciogenic geochemical dispersion need to be taken into consideration when using till geochemistry as one of such input dataset for prospectivity modelling. This paper investigates this issue by developing a fuzzy logic prospectivity model that integrates airborne geophysical data with two different till geochemical datasets. First we use the original geochemical sample set and secondly a spatially corrected dataset that is based on the knowledge of glacial dynamics on the regional scale within the study area. The effect of this correction is tested by comparing the modelling results of both cases using the receiver operating characteristics (ROC) technique to validate the models by using the location of known gold deposits represented by exploration drilling. This study confirms that by taking into consideration the transport caused by the glaciation we can significantly improve the performance of a prospectivity model using till geochemical data.

  19. Neural Net Gains Estimation Based on an Equivalent Model

    Directory of Open Access Journals (Sweden)

    Karen Alicia Aguilar Cruz

    2016-01-01

    Full Text Available A model of an Equivalent Artificial Neural Net (EANN describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN. The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB the factors based on the functional error and the reference signal built with the past information of the system.

  20. Neural Net Gains Estimation Based on an Equivalent Model

    Science.gov (United States)

    Aguilar Cruz, Karen Alicia; Medel Juárez, José de Jesús; Fernández Muñoz, José Luis; Esmeralda Vigueras Velázquez, Midory

    2016-01-01

    A model of an Equivalent Artificial Neural Net (EANN) describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN). The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB) the factors based on the functional error and the reference signal built with the past information of the system. PMID:27366146

  1. Principle Generalized Net Model of a Human Stress Reaction

    Directory of Open Access Journals (Sweden)

    Anthony Shannon

    2008-04-01

    Full Text Available The present study was aimed at investigating the mechanism of a human stress reaction by means of Generalized Nets (GNs. A principle GN-model of the main structures, organs and systems of the human body taking part in the acute and chronic reaction of the organism to a stress stimulus is generated. A possible application of the GN-model of the human stress reaction for testing the effect of known or newly synthesized pharmacological products as well as of food supplements is discussed.

  2. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.

    2014-01-01

    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed

  3. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.

    2014-01-01

    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed wi

  4. Interpretation of heavy metal speciation in sequential extraction using geochemical modelling

    NARCIS (Netherlands)

    Cui, Yanshan; Weng, Liping

    2015-01-01

    Environmental context Heavy metal pollution is a worldwide environmental concern, and the risk depends not only on their total concentration, but also on their chemical speciation. Based on state-of-the-art geochemical modelling, we pinpoint the heavy metal pools approached by the widely used seq

  5. Geochemical modelling of hydrogen gas migration in an unsaturated bentonite buffer

    NARCIS (Netherlands)

    Sedighi, M.; Thomas, H.R.; Al Masum, S.; Vardon, P.J.; Nicholson, D.; Chen, Q.

    2014-01-01

    This paper presents an investigation of the transport and fate of hydrogen gas through compacted bentonite buffer. Various geochemical reactions that may occur in the multiphase and multicomponent system of the unsaturated bentonite buffer are considered. A reactive gas transport model, developed wi

  6. Net-Zero-Energy Model for Sustainable Wastewater Treatment.

    Science.gov (United States)

    Yan, Peng; Qin, Rong-Cong; Guo, Jin-Song; Yu, Qiang; Li, Zhe; Chen, You-Peng; Shen, Yu; Fang, Fang

    2017-01-17

    A large external energy input prevents wastewater treatment from being environmentally sustainable. A net-zero-energy (NZE) wastewater treatment concept based on biomass energy recycling was proposed to avoid wasting resources and to promote energy recycling in wastewater treatment plants (WWTPs). Simultaneously, a theoretical model and boundary condition based on energy balance were established to evaluate the feasibility of achieving NZE in WWTPs; the model and condition were employed to analyze data from 20 conventional WWTPs in China. A total of six WWTPs can currently export excess energy, eight WWTPs can achieve 100% energy self-sufficiency by adjusting the metabolic material allocation, and six municipal WWTPs cannot achieve net-zero energy consumption based on the evaluation of the theoretical model. The NZE model offset 79.5% of the electricity and sludge disposal cost compared with conventional wastewater treatment. The NZE model provides a theoretical basis for the optimization of material regulation for the effective utilization of organic energy from wastewater and promotes engineering applications of the NZE concept in WWTPs.

  7. A Petri Net model for distributed energy system

    Energy Technology Data Exchange (ETDEWEB)

    Konopko, Joanna [Warsaw University of Technology, The Faculty of Electronics and Information Technology, Institute of Computer Science, Nowowiejska Street 15/19, Warsaw 00-665 (Poland)

    2015-12-31

    Electrical networks need to evolve to become more intelligent, more flexible and less costly. The smart grid is the next generation power energy, uses two-way flows of electricity and information to create a distributed automated energy delivery network. Building a comprehensive smart grid is a challenge for system protection, optimization and energy efficient. Proper modeling and analysis is needed to build an extensive distributed energy system and intelligent electricity infrastructure. In this paper, the whole model of smart grid have been proposed using Generalized Stochastic Petri Nets (GSPN). The simulation of created model is also explored. The simulation of the model has allowed the analysis of how close the behavior of the model is to the usage of the real smart grid.

  8. A Petri Net model for distributed energy system

    Science.gov (United States)

    Konopko, Joanna

    2015-12-01

    Electrical networks need to evolve to become more intelligent, more flexible and less costly. The smart grid is the next generation power energy, uses two-way flows of electricity and information to create a distributed automated energy delivery network. Building a comprehensive smart grid is a challenge for system protection, optimization and energy efficient. Proper modeling and analysis is needed to build an extensive distributed energy system and intelligent electricity infrastructure. In this paper, the whole model of smart grid have been proposed using Generalized Stochastic Petri Nets (GSPN). The simulation of created model is also explored. The simulation of the model has allowed the analysis of how close the behavior of the model is to the usage of the real smart grid.

  9. A Quantitative Geochemical Target for Modeling the Formation of the Earth and Moon

    Science.gov (United States)

    Boyce, Jeremy W.; Barnes, Jessica J.; McCubbin, Francis M.

    2017-01-01

    The past decade has been one of geochemical, isotopic, and computational advances that are bringing the laboratory measurements and computational modeling neighborhoods of the Earth-Moon community to ever closer proximity. We are now however in the position to become even better neighbors: modelers can generate testable hypthotheses for geochemists; and geochemists can provide quantitive targets for modelers. Here we present a robust example of the latter based on Cl isotope measurements of mare basalts.

  10. Petri Net Modeling and Performance Analyzing for MGC

    Institute of Scientific and Technical Information of China (English)

    HUANGYongfeng; LIXing; ZHANGKe

    2004-01-01

    This article analyses the advantages of disassembled gateway based on its functions, and introduces the processing of signaling and media streams. Moreover, a function-separated gateway is designed and implemented, which consists of media gateway controller and media gateway. So we propose originally the Stochastic Petri-net model of media gateway controller, and educe the mathematical relationship between load of gateway controller and other factors such as rate of call initialing, delay of call setup, and delay of call release. Lastly, we summarize some important factors which affect performances of gateway, and make a conclusion that decreasing the delay of call setup will improve Media gateway controller efficiency.

  11. Formal Requirements Modeling for Reactive Systems with Coloured Petri Nets

    DEFF Research Database (Denmark)

    Tjell, Simon

    This dissertation presents the contributions of seven publications all concerned with the application of Coloured Petri Nets (CPN) to requirements modeling for reactive systems. The publications are introduced along with relevant background material and related work, and their contributions...... interface composed of recognizable artifacts and activities. The presentation of the three publications related to Use Cases is followed by a the presentation of a publication formalizing some of the guidelines applied for structuring the CPN requirements models|namely the guidelines that make it possible...... activity. The traces are automatically recorded during execution of the model. The second publication presents a formally specified framework for automating a large part of the tasks related to integrating Problem Frames with CPN. The framework is specified in VDM++, and allows the modeler to automatically...

  12. Detection and Modeling of Cyber Attacks with Petri Nets

    Directory of Open Access Journals (Sweden)

    Bartosz Jasiul

    2014-12-01

    Full Text Available The aim of this article is to present an approach to develop and verify a method of formal modeling of cyber threats directed at computer systems. Moreover, the goal is to prove that the method enables one to create models resembling the behavior of malware that support the detection process of selected cyber attacks and facilitate the application of countermeasures. The most common cyber threats targeting end users and terminals are caused by malicious software, called malware. The malware detection process can be performed either by matching their digital signatures or analyzing their behavioral models. As the obfuscation techniques make the malware almost undetectable, the classic signature-based anti-virus tools must be supported with behavioral analysis. The proposed approach to modeling of malware behavior is based on colored Petri nets. This article is addressed to cyber defense researchers, security architects and developers solving up-to-date problems regarding the detection and prevention of advanced persistent threats.

  13. A COMSOL-GEMS interface for modeling coupled reactive-transport geochemical processes

    Science.gov (United States)

    Azad, Vahid Jafari; Li, Chang; Verba, Circe; Ideker, Jason H.; Isgor, O. Burkan

    2016-07-01

    An interface was developed between COMSOL MultiphysicsTM finite element analysis software and (geo)chemical modeling platform, GEMS, for the reactive-transport modeling of (geo)chemical processes in variably saturated porous media. The two standalone software packages are managed from the interface that uses a non-iterative operator splitting technique to couple the transport (COMSOL) and reaction (GEMS) processes. The interface allows modeling media with complex chemistry (e.g. cement) using GEMS thermodynamic database formats. Benchmark comparisons show that the developed interface can be used to predict a variety of reactive-transport processes accurately. The full functionality of the interface was demonstrated to model transport processes, governed by extended Nernst-Plank equation, in Class H Portland cement samples in high pressure and temperature autoclaves simulating systems that are used to store captured carbon dioxide (CO2) in geological reservoirs.

  14. Multifractal interpolation and spectrum-area fractal modeling of stream sediment geochemical data: Implications for mapping exploration targets

    Science.gov (United States)

    Parsa, Mohammad; Maghsoudi, Abbas; Yousefi, Mahyar; Carranza, Emmanuel John M.

    2017-04-01

    The spectrum-area (S-A) fractal model is a powerful tool for decomposition of complex anomaly patterns of gridded geochemical data. Ordinary moving average interpolation techniques are commonly being used for gridding geochemical data; however, these methods suffer from two major drawbacks of (1) ignoring the locally high values and (2) smoothing the interpolated surface. Multifractal moving average interpolation methods have been developed to overcome the shortcomings of ordinary moving average methods. This study seeks to compare two sets of multifractal and ordinary gridded geochemical data using success rate curves and applies the S-A fractal model to decompose anomalous geochemical patterns. A set of stream sediment geochemical data in Ahar area, NW Iran, was used as a case study. Then, a mineralization-related multi-element geochemical signature was gridded by ordinary and multifractal approaches and considered for further analyses. The S-A fractal method was applied to decompose anomaly and background components of the resultant multi-element geochemical signature. Exploration targets were delimited and further evaluated using two bivariate statistical procedures of Student's t-value and normalized density index. The results revealed that (a) application of multifractal gridded data enhances the predicting ability of geochemical signatures, (b) application of S-A fractal model on multifractal gridded data allows for superior discrimination of geochemical anomalies, and (c) the multi-element geochemical anomalies in the Ahar area related to porphyry-Cu deposits were properly delineated through sequence application of multifractal interpolation and S-A fractal model.

  15. Text Summarization Using FrameNet-Based Semantic Graph Model

    Directory of Open Access Journals (Sweden)

    Xu Han

    2016-01-01

    Full Text Available Text summarization is to generate a condensed version of the original document. The major issues for text summarization are eliminating redundant information, identifying important difference among documents, and recovering the informative content. This paper proposes a Semantic Graph Model which exploits the semantic information of sentence using FSGM. FSGM treats sentences as vertexes while the semantic relationship as the edges. It uses FrameNet and word embedding to calculate the similarity of sentences. This method assigns weight to both sentence nodes and edges. After all, it proposes an improved method to rank these sentences, considering both internal and external information. The experimental results show that the applicability of the model to summarize text is feasible and effective.

  16. GEOCHEMICAL TESTING AND MODEL DEVELOPMENT - RESIDUAL TANK WASTE TEST PLAN

    Energy Technology Data Exchange (ETDEWEB)

    CANTRELL KJ; CONNELLY MP

    2010-03-09

    This Test Plan describes the testing and chemical analyses release rate studies on tank residual samples collected following the retrieval of waste from the tank. This work will provide the data required to develop a contaminant release model for the tank residuals from both sludge and salt cake single-shell tanks. The data are intended for use in the long-term performance assessment and conceptual model development.

  17. Manual hierarchical clustering of regional geochemical data using a Bayesian finite mixture model

    Science.gov (United States)

    Ellefsen, Karl J.; Smith, David

    2016-01-01

    Interpretation of regional scale, multivariate geochemical data is aided by a statistical technique called “clustering.” We investigate a particular clustering procedure by applying it to geochemical data collected in the State of Colorado, United States of America. The clustering procedure partitions the field samples for the entire survey area into two clusters. The field samples in each cluster are partitioned again to create two subclusters, and so on. This manual procedure generates a hierarchy of clusters, and the different levels of the hierarchy show geochemical and geological processes occurring at different spatial scales. Although there are many different clustering methods, we use Bayesian finite mixture modeling with two probability distributions, which yields two clusters. The model parameters are estimated with Hamiltonian Monte Carlo sampling of the posterior probability density function, which usually has multiple modes. Each mode has its own set of model parameters; each set is checked to ensure that it is consistent both with the data and with independent geologic knowledge. The set of model parameters that is most consistent with the independent geologic knowledge is selected for detailed interpretation and partitioning of the field samples.

  18. Autonomic Model for Self-Configuring C#.NET Applications

    CERN Document Server

    Bassil, Youssef

    2012-01-01

    With the advances in computational technologies over the last decade, large organizations have been investing in Information Technology to automate their internal processes to cut costs and efficiently support their business projects. However, this comes to a price. Business requirements always change. Likewise, IT systems constantly evolves as developers make new versions of them, which require endless administrative manual work to customize and configure them, especially if they are being used in different contexts, by different types of users, and for different requirements. Autonomic computing was conceived to provide an answer to these ever-changing requirements. Essentially, autonomic systems are self-configuring, self-healing, self-optimizing, and self-protecting; hence, they can automate all complex IT processes without human intervention. This paper proposes an autonomic model based on Venn diagram and set theory for self-configuring C#.NET applications, namely the self-customization of their GUI, ev...

  19. Hydrologic and geochemical modeling of a karstic Mediterranean watershed

    Directory of Open Access Journals (Sweden)

    N. P. Nikolaidis

    2012-01-01

    Full Text Available The SWAT model was modified to simulate the hydrologic and chemical response of karstic systems and assess the impacts of land use management and climate change of an intensively managed Mediterranean watershed in Crete, Greece. A methodology was developed for the determination of the extended karst area contributing to the spring flow as well as the degree of dilution of nitrates due to permanent karst water volume. The modified SWAT model has been able to capture the temporal variability of both karst flow and surface runoff using high frequency monitoring data collected since 2004 in addition to long term flow time series collected since 1973. The overall hydrologic budget of the karst was estimated and its evaporative losses were calculated to be 28% suggesting a very high rate of karst infiltration. Nitrate chemistry of the karst was simulated by calibrating a dilution factor allowing for the estimation of the total karstic groundwater volume to approximately 500 million m3 of reserve water. The nitrate simulation results suggested a significant impact of livestock grazing on the karstic groundwater and on surface water quality. Finally, simulation results for a set of climate change scenarios suggested a 17% decrease in precipitation, 8% decrease in ET and 22% decrease in flow in 2030–2050 compared to 2010–2020. A validated tool for integrated water management of karst areas has been developed, providing policy makers an instrument for water management that could tackle the increasing water scarcity in the island.

  20. Thermodynamic Data for Geochemical Modeling of Carbonate Reactions Associated with CO2 Sequestration – Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, Kenneth M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2010-09-01

    Permanent storage of anthropogenic CO2 in deep geologic formations is being considered as a means to reduce the concentration of atmospheric CO2 and thus its contribution to global climate change. To ensure safe and effective geologic sequestration, numerous studies have been completed of the extent to which the CO2 migrates within geologic formations and what physical and geochemical changes occur in these formations when CO2 is injected. Sophisticated, computerized reservoir simulations are used as part of field site and laboratory CO2 sequestration studies. These simulations use coupled multiphase flow-reactive chemical transport models and/or standalone (i.e., no coupled fluid transport) geochemical models to calculate gas solubility, aqueous complexation, reduction/oxidation (redox), and/or mineral solubility reactions related to CO2 injection and sequestration. Thermodynamic data are critical inputs to modeling geochemical processes. The adequacy of thermodynamic data for carbonate compounds has been identified as an important data requirement for the successful application of these geochemical reaction models to CO2 sequestration. A review of thermodynamic data for CO2 gas and carbonate aqueous species and minerals present in published data compilations and databases used in geochemical reaction models was therefore completed. Published studies that describe mineralogical analyses from CO2 sequestration field and natural analogue sites and laboratory studies were also reviewed to identify specific carbonate minerals that are important to CO2 sequestration reactions and therefore require thermodynamic data. The results of the literature review indicated that an extensive thermodynamic database exists for CO2 and CH4 gases, carbonate aqueous species, and carbonate minerals. Values of ΔfG298° and/or log Kr,298° are available for essentially all of these compounds. However, log Kr,T° or heat capacity values at temperatures above 298 K exist for less than

  1. Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems

    Science.gov (United States)

    Giles, Stuart A.; Granitto, Matthew; Eppinger, Robert G.

    2009-01-01

    The database herein was initiated, designed, and populated to collect and integrate geochemical, geologic, and mineral deposit data in an organized manner to facilitate geoenvironmental mineral deposit modeling. The Microsoft Access database contains data on a variety of mineral deposit types that have variable environmental effects when exposed at the ground surface by mining or natural processes. The data tables describe quantitative and qualitative geochemical analyses determined by 134 analytical laboratory and field methods for over 11,000 heavy-mineral concentrate, rock, sediment, soil, vegetation, and water samples. The database also provides geographic information on geology, climate, ecoregion, and site contamination levels for over 3,000 field sites in North America.

  2. Modules based on the geochemical model PHREEQC for use in scripting and programming languages

    Science.gov (United States)

    Charlton, Scott R.; Parkhurst, David L.

    2011-10-01

    The geochemical model PHREEQC is capable of simulating a wide range of equilibrium reactions between water and minerals, ion exchangers, surface complexes, solid solutions, and gases. It also has a general kinetic formulation that allows modeling of nonequilibrium mineral dissolution and precipitation, microbial reactions, decomposition of organic compounds, and other kinetic reactions. To facilitate use of these reaction capabilities in scripting languages and other models, PHREEQC has been implemented in modules that easily interface with other software. A Microsoft COM (component object model) has been implemented, which allows PHREEQC to be used by any software that can interface with a COM server—for example, Excel ®, Visual Basic ®, Python, or MATLAB ®. PHREEQC has been converted to a C++ class, which can be included in programs written in C++. The class also has been compiled in libraries for Linux and Windows that allow PHREEQC to be called from C++, C, and Fortran. A limited set of methods implements the full reaction capabilities of PHREEQC for each module. Input methods use strings or files to define reaction calculations in exactly the same formats used by PHREEQC. Output methods provide a table of user-selected model results, such as concentrations, activities, saturation indices, and densities. The PHREEQC module can add geochemical reaction capabilities to surface-water, groundwater, and watershed transport models. It is possible to store and manipulate solution compositions and reaction information for many cells within the module. In addition, the object-oriented nature of the PHREEQC modules simplifies implementation of parallel processing for reactive-transport models. The PHREEQC COM module may be used in scripting languages to fit parameters; to plot PHREEQC results for field, laboratory, or theoretical investigations; or to develop new models that include simple or complex geochemical calculations.

  3. Modules based on the geochemical model PHREEQC for use in scripting and programming languages

    Science.gov (United States)

    Charlton, Scott R.; Parkhurst, David L.

    2011-01-01

    The geochemical model PHREEQC is capable of simulating a wide range of equilibrium reactions between water and minerals, ion exchangers, surface complexes, solid solutions, and gases. It also has a general kinetic formulation that allows modeling of nonequilibrium mineral dissolution and precipitation, microbial reactions, decomposition of organic compounds, and other kinetic reactions. To facilitate use of these reaction capabilities in scripting languages and other models, PHREEQC has been implemented in modules that easily interface with other software. A Microsoft COM (component object model) has been implemented, which allows PHREEQC to be used by any software that can interface with a COM server—for example, Excel®, Visual Basic®, Python, or MATLAB". PHREEQC has been converted to a C++ class, which can be included in programs written in C++. The class also has been compiled in libraries for Linux and Windows that allow PHREEQC to be called from C++, C, and Fortran. A limited set of methods implements the full reaction capabilities of PHREEQC for each module. Input methods use strings or files to define reaction calculations in exactly the same formats used by PHREEQC. Output methods provide a table of user-selected model results, such as concentrations, activities, saturation indices, and densities. The PHREEQC module can add geochemical reaction capabilities to surface-water, groundwater, and watershed transport models. It is possible to store and manipulate solution compositions and reaction information for many cells within the module. In addition, the object-oriented nature of the PHREEQC modules simplifies implementation of parallel processing for reactive-transport models. The PHREEQC COM module may be used in scripting languages to fit parameters; to plot PHREEQC results for field, laboratory, or theoretical investigations; or to develop new models that include simple or complex geochemical calculations.

  4. Transactions on Petri Nets and Other Models of Concurrency VII

    DEFF Research Database (Denmark)

    -stage refereeing process. ToPNoC contains: - Revised versions of a selection of the best papers from workshops and tutorials at the annual Petri net conferences - Special sections/issues within particular subareas (similar to those published in the Advances in Petri Nets series) - Other papers invited...

  5. PhreeqcRM: A reaction module for transport simulators based on the geochemical model PHREEQC

    Science.gov (United States)

    Parkhurst, David L.; Wissmeier, Laurin

    2015-09-01

    PhreeqcRM is a geochemical reaction module designed specifically to perform equilibrium and kinetic reaction calculations for reactive transport simulators that use an operator-splitting approach. The basic function of the reaction module is to take component concentrations from the model cells of the transport simulator, run geochemical reactions, and return updated component concentrations to the transport simulator. If multicomponent diffusion is modeled (e.g., Nernst-Planck equation), then aqueous species concentrations can be used instead of component concentrations. The reaction capabilities are a complete implementation of the reaction capabilities of PHREEQC. In each cell, the reaction module maintains the composition of all of the reactants, which may include minerals, exchangers, surface complexers, gas phases, solid solutions, and user-defined kinetic reactants. PhreeqcRM assigns initial and boundary conditions for model cells based on standard PHREEQC input definitions (files or strings) of chemical compositions of solutions and reactants. Additional PhreeqcRM capabilities include methods to eliminate reaction calculations for inactive parts of a model domain, transfer concentrations and other model properties, and retrieve selected results. The module demonstrates good scalability for parallel processing by using multiprocessing with MPI (message passing interface) on distributed memory systems, and limited scalability using multithreading with OpenMP on shared memory systems. PhreeqcRM is written in C++, but interfaces allow methods to be called from C or Fortran. By using the PhreeqcRM reaction module, an existing multicomponent transport simulator can be extended to simulate a wide range of geochemical reactions. Results of the implementation of PhreeqcRM as the reaction engine for transport simulators PHAST and FEFLOW are shown by using an analytical solution and the reactive transport benchmark of MoMaS.

  6. A Petri net-based approach for supporting aspect-oriented modeling

    Institute of Scientific and Technical Information of China (English)

    Lianwei GUAN; Xingyu LI; Hao HU; Jian LU

    2008-01-01

    The concept of aspect-orientation allows for modularizing crosscutting concerns as aspect modules. Aspect-orientation originally emerged at the program-ming level, and has stretched over other development phases now. Among them aspect-oriented modeling (AOM) is a hot topic, and there are many approaches supporting it. Petri net is a good formalism which can provide the foundations for modeling software and simulating its execution, but fails to resolve the prob-lem of crosscutting concerns to support AOM. So, this paper presents an approach which extends the Petri net so as to support the AOM. In this paper, the basic functions of the system are modeled as base net by Petri net, and the crosscutting concerns are modeled as aspect nets. In order to analyze the whole system, woven mechanism is proposed to compose the aspect nets and base net together. The problems about aspect-aspect conflict and conflict relations may exist among the aspect nets matching the shared join point, thus this paper propose solutions to resolve them. The Object Petri net which is an extension of traditional Petri net is also extended so as to support aspect-oriented mod-eling here.

  7. Coloured Petri Nets and CPN Tools for Modelling and Validation of Concurrent Systems

    DEFF Research Database (Denmark)

    Jensen, Kurt; Kristensen, Lars Michael; Wells, Lisa Marie

    2007-01-01

    Coloured Petri Nets (CPNs) is a language for the modeling and validation og systems in which concurrency, communication, and synchronisation play a major role. Coloured Petri Nets is a descrete-event modeling language combining Petri Nets with the funcitonal programming language Standard ML. Petr...... with user-defined Standard ML functions. A license for CPN Tools can be obtained free of charge, also for commercial use....

  8. Experimental modelling of transverse oscillations in aquaculture netting parallel to the flow — Sounds baffling

    Science.gov (United States)

    Johnson, Andrew; Balash, Cheslav

    2015-06-01

    Numerous studies have been undertaken to improve the viability, durability and suitability of materials and methods used for aquaculture enclosures. While many of the previous studies considered macro-deformation of nets, there is a paucity of information on netting micro-deformation. When aquaculture pens are towed, industry operators have observed the motion described as "baffling" — the transverse oscillation of the net planes parallel and near parallel to the flow. The difficulty to observe and assess baffling motion in a controlled experimental environment is to sufficiently reproduce netting boundary conditions and the flow environment experienced at sea. The focus of the present study was to develop and assess experimental methods for visualisation and quantification of these transverse oscillations. Four net-rig configurations with varied boundary conditions and model-netting properties were tested in a flume tank. While the Reynolds number was not equivalent to full-scale, usage of the pliable and fine mesh model netting that enabled baffling to develop at low flow velocities was deemed to be of a larger relevance to this initial study. Baffling was observed in the testing frame that constrained the net sheet on the leading edge, similarly to a flag attachment onto a pole. Baffling motion increased the hydrodynamic drag of the net by 35%-58% when compared to the previously developed formula for taut net sheets aligned parallel to the flow. Furthermore, it was found that the drag due to baffling decreased with the increasing velocity over the studied Reynolds numbers (below 200); and the drag coefficient was non-linear for Reynolds numbers below 120. It is hypothesised that baffling motion is initially propagated by vortex shedding of the netting twine which causes the netting to oscillate; there after the restoring force causes unstable pressure differences on each side of the netting which excites the amplitude of the netting oscillations.

  9. Leaching of chromium from chromium contaminated soil: Speciation study and geochemical modeling

    Directory of Open Access Journals (Sweden)

    Anđelković Darko H.

    2012-01-01

    Full Text Available Distribution of chromium between soil and leachate was monitored. A natural process of percolating rainwater through the soil was simulated in the laboratory conditions and studied with column leaching extraction. Migration of chromium in the soil is conditioned by the level of chromium soil contamination, the soil organic matter content, and rainwater acidity. Chromium (III and chromium(VI were determined by spectrophotometric method with diphenilcarbazide in acidic media. Comparing the results of chromium speciation in leachate obtained by experimental model systems and geochemical modelling calculations using Visual MINTEQ model, a correlation was observed regarding the influence of the tested parameters. Leachate solutions showed that the concentration of Cr depended on the organic matter content. The influence of pH and soil organic matter content is in compliance after its definition through experimental and theoretical way. The computer model - Stockholm Humic Model used to evaluate the leaching results corresponded rather well with the measured values.

  10. Testing Benjamin Graham’s net current asset value model

    Directory of Open Access Journals (Sweden)

    Chongsoo An

    2015-02-01

    Full Text Available The objective of this paper is to empirically test one of Graham’s investment methods based on the net current asset value (NCAV. The NCAV is truly unique, and conservative, and commonly known as the net-net method.  The ratio of the net current asset value to market value (NCAV/MV was employed in this study to test a stock’s performance comparing to the performance of S&P 500 as the market index. We used all stocks in Portfolio123 whose raw data were supplied by Compustat, Standard & Poors, Capital IQ, and Reuters for the period of January 2, 1999 to August 31, 2012. The overall results show that the firms with high net current asset values outperform the market. These results are strong in the up market. It can be argued that the firms with a high NCAV/MV ratio are likely to move toward their fundamental value and generate high excess return because its stock prices are now undervalued. The implications of the study are: (a a positive NCAV/MV ratio may be a good indicator of the underpriced security; (b investing in the growth period and avoiding the downturn period leads investors to earn much higher returns from the firms with a high NCAV/MV ratio; and (c The NCAV/MV strategy requires a longer holding period of the portfolio in order to generate excess returns.

  11. A geochemical transport model for thermo-hydro-chemical (THC) coupled processes with saline water

    Science.gov (United States)

    Xie, Mingliang; Kolditz, Olaf; Moog, Helge C.

    2011-02-01

    Anhydrous MgSO4 is considered as a potential sealing material for the isolation of high-level-waste repositories in salt rock. When an aqueous solution, usually a brine type, penetrates the sealing, different MgSO4 hydrates along with other mineral phases form, removing free water from the solution. The uptake of water leads to an overall increase of solid phase volume. If deformation is constrained, the pore volume decreases and permeability is reduced. In order to simulate such processes, especially for conditions without free water, a coupling between OpenGeoSys and thermodynamic equilibrium calculations were implemented on the basis of the commercially available thermodynamic simulator ChemApp and the object-oriented programming finite-element method simulator OpenGeoSys. ChemApp uses the Gibbs energy minimization approach for the geochemical reaction simulation. Based on this method, the thermodynamic equilibrium of geochemical reactions can be calculated by giving the amount of each system component and the molar Gibbs energy of formation for all the possible phases and phase constituents. Activity coefficients in high-saline solutions were calculated using the Pitzer formalism. This model has the potential to handle 1-D, 2-D, and 3-D saturated and nonsaturated thermo-hydro-chemical coupled processes even with highly saline solutions under complex conditions. The model was verified by numerical comparison with other simulators and applied for the modeling of SVV experimental data.

  12. Geochemical modeling of groundwater evolution in a volcanic aquifer system of Kumamoto area, Japan

    Science.gov (United States)

    Hossain, S.; Hosono, T.; Ide, K.; Shimada, J.

    2013-12-01

    Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater in a volcanic aquifer system of Kumamoto area (103 Km2) in southern Japan. The modeling was based on flow paths proposed by different researcher using different techniques, and detailed chemical analysis of groundwater along the flow paths. Potential phases were constrained using general trends in hydrochemical data of groundwater, mineralogical data, and saturation indices data of minerals in groundwater. Hydrochemical data from a total of 180 spring, river and well water samples were used to evaluate water quality and to determine processes that control groundwater chemistry. The samples from the area were classified as recharge zone water (Ca-HCO3 and Ca-SO4 type), lateral flow to discharge zone water (Ca-HCO3 and Na-HCO3 type) and stagnant zone water (Na-Cl type). The inverse geochemical modeling demonstrated that relatively few phases are required to derive water chemistry in the area. The downstream changes in groundwater chemistry could be largely explained by the weathering of plagioclase to kaolinite, with possible contributions from weathering of biotite and pyroxene. In a broad sense, the reactions responsible for the hydrochemical evolution in the area fall into three categories (1) silicate weathering reactions (2) precipitation of amorphous silica and clay minerals and (3) Cation exchange reactions of Ca2+ to Na+.

  13. Integrating Geochemical and Geodynamic Numerical Models of Mantle Evolution and Plate Tectonics

    Science.gov (United States)

    Tackley, P. J.; Xie, S.

    2001-12-01

    The thermal and chemical evolution of Earth's mantle and plates are inextricably coupled by the plate tectonic - mantle convective system. Convection causes chemical differentiation, recycling and mixing, while chemical variations affect the convection through physical properties such as density and viscosity which depend on composition. It is now possible to construct numerical mantle convection models that track the thermo-chemical evolution of major and minor elements, and which can be used to test prospective models and hypotheses regarding Earth's chemical and thermal evolution. Model thermal and chemical structures can be compared to results from seismic tomography, while geochemical signatures (e.g., trace element ratios) can be compared to geochemical observations. The presented, two-dimensional model combines a simplified 2-component major element model with tracking of the most important trace elements, using a tracer method. Melting is self-consistently treated using a solidus, with melt placed on the surface as crust. Partitioning of trace elements occurs between melt and residue. Decaying heat-producing elements and secular cooling of the mantle and core provide the driving heat sources. Pseudo-plastic yielding of the lithosphere gives a first-order approximation of plate tectonics, and also allows planets with a rigid lid or intermittent plate tectonics to be modeled simply by increasing the yield strength. Preliminary models with an initially homogeneous mantle show that regions with a HIMU-like signature can be generated by crustal recycling, and regions with high 3He/4He ratios can be generated by residuum recycling. Outgassing of Argon is within the observed range. Models with initially layered mantles will also be investigated. In future it will be important to include a more realistic bulk compositional model that allows continental crust as well as oceanic crust to form, and to extend the model to three dimensions since toroidal flow may alter

  14. Model predictive combustion control based on neural nets

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, D. [Powitec Intelligent Technologies GmbH, Essen (Germany); Kampschreuer, T. [AVR Afvalverwerking B.V., Duiven/Arnheim (Netherlands)

    2008-07-01

    The first closed-loop Neural Net combustion controller in the Netherlands has been installed at the HVC plant in Alkmaar. During the summer 2006 the first of the 'old' three lines was equipped with an individually controllable primary air distribution. As 'fire controller' the combustion optimiser from Powitec, the PiT Navigator, was selected, a system using digital image processing and neural nets. This paper shows the results from operating the plant with and without the NMPC optimiser and from the performance tests. (orig.)

  15. A hybrid model of the CO2 geochemical cycle and its application to large impact events

    Science.gov (United States)

    Kasting, J. F.; Pollack, J. B.; Toon, O. B.; Richardson, S. M.

    1986-01-01

    The effects of a large asteriod or comet impact on modern and ancient marine biospheres are analyzed. A hybrid model of the carbonate-silicate geochemical cycle, which is capable of calculating the concentrations of carbon dioxide in the atmosphere, ocean, and sedimentary rocks, is described. The differences between the Keir and Berger (1983) model and the hybrid model are discussed. Equilibrium solutions are derived for the preindustrial atmosphere/ocean system and for a system similar to that of the late Cretaceous Period. The model data reveal that globl darkening caused by a stratospheric dust veil could destroy the existing phytoplankton within a period of several weeks or months, nd the dissolution of atmospheric NO(x) compounds would lower the pH of ocean surface waters and release CO2 into the atmosphere. It is noted that the surface temperatures could be increased by several degrees and surface oceans would be uninhabitable for calcaerous organisms for approximately 20 years.

  16. Gluon Saturation Model with Geometric Scaling for Net-Baryon Distributions in Relativistic Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    李双; 冯笙琴

    2012-01-01

    The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. The net-baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions are investigated by taking advantage of the gluon saturation model with geometric scaling. Predications are made for the net-baryon rapidity distributions, mean rapidity loss and gluon saturation features in central Pb + Pb collisions at LHC.

  17. BioModels.net Web Services, a free and integrated toolkit for computational modelling software.

    Science.gov (United States)

    Li, Chen; Courtot, Mélanie; Le Novère, Nicolas; Laibe, Camille

    2010-05-01

    Exchanging and sharing scientific results are essential for researchers in the field of computational modelling. BioModels.net defines agreed-upon standards for model curation. A fundamental one, MIRIAM (Minimum Information Requested in the Annotation of Models), standardises the annotation and curation process of quantitative models in biology. To support this standard, MIRIAM Resources maintains a set of standard data types for annotating models, and provides services for manipulating these annotations. Furthermore, BioModels.net creates controlled vocabularies, such as SBO (Systems Biology Ontology) which strictly indexes, defines and links terms used in Systems Biology. Finally, BioModels Database provides a free, centralised, publicly accessible database for storing, searching and retrieving curated and annotated computational models. Each resource provides a web interface to submit, search, retrieve and display its data. In addition, the BioModels.net team provides a set of Web Services which allows the community to programmatically access the resources. A user is then able to perform remote queries, such as retrieving a model and resolving all its MIRIAM Annotations, as well as getting the details about the associated SBO terms. These web services use established standards. Communications rely on SOAP (Simple Object Access Protocol) messages and the available queries are described in a WSDL (Web Services Description Language) file. Several libraries are provided in order to simplify the development of client software. BioModels.net Web Services make one step further for the researchers to simulate and understand the entirety of a biological system, by allowing them to retrieve biological models in their own tool, combine queries in workflows and efficiently analyse models.

  18. Solid phase studies and geochemical modelling of low-cost permeable reactive barriers

    Energy Technology Data Exchange (ETDEWEB)

    Bartzas, Georgios, E-mail: gbartzas@metal.ntua.gr [Laboratory of Metallurgy, School of Mining and Metallurgical Engineering, National Technical University of Athens, Zografos Campus, 15780 Athens (Greece); Komnitsas, Kostas [Department of Mineral Resources Engineering, Technical University of Crete, 73100 Chania (Greece)

    2010-11-15

    A continuous column experiment was carried out under dynamic flow conditions in order to study the efficiency of low-cost permeable reactive barriers (PRBs) to remove several inorganic contaminants from acidic solutions. A 50:50 w/w waste iron/sand mixture was used as candidate reactive media in order to activate precipitation and promote sorption and reduction-oxidation mechanisms. Solid phase studies of the exhausted reactive products after column shutdown, using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), confirmed that the principal Fe corrosion products identified in the reactive zone are amorphous iron (hydr)oxides (maghemite/magnetite and goethite), intermediate products (sulfate green rust), and amorphous metal sulfides such as amFeS and/or mackinawite. Geochemical modelling of the metal removal processes, including interactions between reactive media, heavy metal ions and sulfates, and interpretation of the ionic profiles was also carried out by using the speciation/mass transfer computer code PHREEQC-2 and the WATEQ4F database. Mineralogical characterization studies as well as geochemical modelling calculations also indicate that the effect of sulfate and silica sand on the efficiency of the reactive zone should be considered carefully during design and operation of low-cost field PRBs.

  19. Fluid-rock geochemical interaction for modelling calibration in geothermal exploration in Indonesia

    Science.gov (United States)

    Deon, Fiorenza; Barnhoorn, Auke; Lievens, Caroline; Ryannugroho, Riskiray; Imaro, Tulus; Bruhn, David; van der Meer, Freek; Hutami, Rizki; Sibarani, Besteba; Sule, Rachmat; Saptadij, Nenny; Hecker, Christoph; Appelt, Oona; Wilke, Franziska

    2017-04-01

    Indonesia with its large, but partially unexplored geothermal potential is one of the most interesting and suitable places in the world to conduct geothermal exploration research. This study focuses on geothermal exploration based on fluid-rock geochemistry/geomechanics and aims to compile an overview on geochemical data-rock properties from important geothermal fields in Indonesia. The research carried out in the field and in the laboratory is performed in the framework of the GEOCAP cooperation (Geothermal Capacity Building program Indonesia- the Netherlands). The application of petrology and geochemistry accounts to a better understanding of areas where operating power plants exist but also helps in the initial exploration stage of green areas. Because of their relevance and geological setting geothermal fields in Java, Sulawesi and the sedimentary basin of central Sumatra have been chosen as focus areas of this study. Operators, universities and governmental agencies will benefit from this approach as it will be applied also to new green-field terrains. By comparing the characteristic of the fluids, the alteration petrology and the rock geochemistry we also aim to contribute to compile an overview of the geochemistry of the important geothermal fields in Indonesia. At the same time the rock petrology and fluid geochemistry will be used as input data to model the reservoir fluid composition along with T-P parameters with the geochemical workbench PHREEQC. The field and laboratory data are mandatory for both the implementation and validation of the model results.

  20. Estimating net present value variability for deterministic models

    NARCIS (Netherlands)

    van Groenendaal, W.J.H.

    1995-01-01

    For decision makers the variability in the net present value (NPV) of an investment project is an indication of the project's risk. So-called risk analysis is one way to estimate this variability. However, risk analysis requires knowledge about the stochastic character of the inputs. For large, long

  1. Geochemical modelling of bentonite porewater in high-level waste repositories

    Science.gov (United States)

    Wersin, Paul

    2003-03-01

    The description of the geochemical properties of the bentonite backfill that serves as engineered barrier for nuclear repositories is a central issue for perfomance assessment since these play a large role in determining the fate of contaminants released from the waste. In this study the porewater chemistry of bentonite was assessed with a thermodynamic modelling approach that includes ion exchange, surface complexation and mineral equilibrium reactions. The focus was to identify the geochemical reactions controlling the major ion chemistry and acid-base properties and to explore parameter uncertainties specifically at high compaction degrees. First, the adequacy of the approach was tested with two distinct surface complexation models by describing recent experimental data performed at highly varying solid/liquid ratios and ionic strengths. The results indicate adequate prediction of the entire experimental data set. Second, the modelling was extended to repository conditions, taking as an example the current Swiss concept for high-level waste where the compacted bentonite backfill is surrounded by argillaceous rock. The main reactions controlling major ion chemistry were found to be calcite equilibrium and concurrent Na-Ca exchange reactions and de-protonation of functional surface groups. Third, a sensitivity analysis of the main model parameters was performed. The results thereof indicate a remarkable robustness of the model with regard to parameter uncertainties. The bentonite system is characterised by a large acid-base buffering capacity which leads to stable pH-conditions. The uncertainty in pH was found to be mainly induced by the pCO 2 of the surrounding host rock. The results of a simple diffusion-reaction model indicate only minor changes of porewater composition with time, which is primarily due to the geochemical similarities of the bentonite and the argillaceous host rock. Overall, the results show the usefulness of simple thermodynamic models to

  2. Computational Modeling aided Near Net Shape Manufacturing for Aluminum Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will focus on developing and validating computational models for near-net shape processing of aluminum alloys. Computational models will be developed...

  3. Fast and Flexible Modelling of Real-Time Systems with RTCP-Nets

    Directory of Open Access Journals (Sweden)

    Marcin Szpyrka

    2004-01-01

    Full Text Available A large number of formalisms has been proposed for real-time systems modelling. However, formal methods are not widely used in industrial software development. Such a situation could be treated as a result of a lack of suitable tools for fast designing of a model, its analysis and modification. RTCP-nets have been defined to facilitate fast modelling of embedded systems incorporating rule-based systems. Computer tools that are being developed for RTCP-nets, use a template mechanism to allow users to design models and manipulate its properties fast and effectively. Both theoretical and practical aspects of RTCP-nets are presented in the paper.

  4. Metal availability in a highly contaminated, dredged-sediment disposal site: Field measurements and geochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lions, Julie, E-mail: j.lions@brgm.f [BRGM, 3 Avenue Claude Guillemin, 45060 Orleans Cedex 2 (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France); Guerin, Valerie; Bataillard, Philippe [BRGM, 3 Avenue Claude Guillemin, 45060 Orleans Cedex 2 (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France); Lee, Jan van der [Mines ParisTech, Centre de Geosciences, 77305 Fontainebleau Cedex (France); Laboudigue, Agnes [Univ Lille Nord de France, F-59000 Lille (France); EMDouai, MPE-GCE, F-59500 Douai (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France)

    2010-09-15

    Two complementary approaches were used to characterize arsenic and metal mobilizations from a dredged-sediment disposal site: a detailed field study combined with hydrogeochemical modeling. Contaminants in sediments were found to be mainly present as sulfides subject to oxidation. Secondary phases (carbonates, sulfates, (hydr)oxides) were also observed. Oxidative processes occurred at different rates depending on physicochemical conditions and contaminant contents in the sediment. Two distinct areas were identified on the site, each corresponding to a specific contaminant mobility behavior. In a reducing area, Fe and As were highly soluble and illustrated anoxic behavior. In well-oxygenated material, groundwater was highly contaminated in Zn, Cd and Pb. A third zone in which sediments and groundwater were less contaminated was also characterized. This study enabled us to prioritize remediation work, which should aim to limit infiltration and long-term environmental impact. - A detailed case study of metal behavior in a dredged-sediment disposal site combined with geochemical modeling.

  5. Modeling of geochemical interactions between acidic and neutral fluids in the Onikobe Geothermal Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Todaka, Norifumi; Akasaka, Chitoshi; Xu, Tianfu; Pruess, Karsten

    2003-01-10

    Two types of fluids are encountered in the Onikobe geothermal reservoir, one is neutral and the other is acidic (pH=3). It is hypothesized that acidic fluid might be upwelling along a fault zone and that an impermeable barrier might be present between the acidic and neutral fluid zones. We carried out reactive geothermal transport simulations using TOUGHREACT (Xu and Pruess, 1998 and 2001) to test such a conceptual model. One-dimensional models were used to study the geochemical behavior due to mixing of the two fluids. Mn-rich smectite precipitated near the mixing front and is likely to form an impermeable barrier between regions with acidic and neutral fluids.

  6. Error Propagation in Equations for Geochemical Modeling of Radiogenic Isotopes in Two-Component Mixing

    Indian Academy of Sciences (India)

    Surendra P Verma

    2000-03-01

    This paper presents error propagation equations for modeling of radiogenic isotopes during mixing of two components or end-members. These equations can be used to estimate errors on an isotopic ratio in the mixture of two components, as a function of the analytical errors or the total errors of geological field sampling and analytical errors. Two typical cases (``Small errors'' and ``Large errors'') are illustrated for mixing of Sr isotopes. Similar examples can be formulated for the other radiogenic isotopic ratios. Actual isotopic data for sediment and basalt samples from the Cocos plate are also included to further illustrate the use of these equations. The isotopic compositions of the predicted mixtures can be used to constrain the origin of magmas in the central part of the Mexican Volcanic Belt. These examples show the need of high quality experimental data for them to be useful in geochemical modeling of magmatic processes.

  7. Influence of ammonia on leaching behaviors of incineration fly ash and its geochemical modeling

    DEFF Research Database (Denmark)

    Astrup, Thomas Fruergaard; Guan, Zhen Zhen; Chen, De Zhen

    2013-01-01

    Incineration fly ash could be contaminated with NH3 that was slipped from the ammonia-based selective non-catalytic reduction(SNCR) process and from evaporation of municipal solid wastes' leachate involved in the wastes. This research was conducted to investigate the impacts of ammonia on leaching...... of dissolved organic carbon (DOC) and metals from incineration fly ash in the pH range of 3.66-12.44 with an active ammonia spike. A geochemical modeling software Visual MINTEQ was adopted to calculate the chemical speciation of metals under the leaching conditions to reveal the mechanism behind the impacts...... by precipitation/dissolution and surface complexation/precipitation processes; Visual MINTEQ modeling could well describe the leaching behaviors of Al, Cu, Pb and Zn from incineration fly ash....

  8. Thermo-hydro-geochemical modelling of the bentonite buffer. LOT A2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sena, Clara; Salas, Joaquin; Arcos, David (Amphos 21 Consulting S.L., Barcelona (Spain))

    2010-12-15

    The Swedish Nuclear Fuel and waste management company (SKB) is conducting a series of long term buffer material (LOT) tests at the Aespoe Hard Rock Laboratory (HRL) to test the behaviour of the bentonite buffer under conditions similar to those expected in a KBS-3 deep geological repository for high level nuclear waste (HLNW). In the present work a numerical model is developed to simulate (i) the thermo-hydraulic, (ii) transport and (iii) geochemical processes that have been observed in the LOT A2 test parcel. The LOT A2 test lasted approximately 6 years, and consists of a 4 m long vertical borehole drilled in diorite rock, from the ground of the Aespoe HRL tunnel. The borehole is composed of a central heater, maintained at 130 deg C in the lower 2 m of the borehole, a copper tube surrounding the heater and a 100 mm thick ring of pre-compacted Wyoming MX-80 bentonite around the copper tube /Karnland et al. 2009/. The numerical model developed here is a 1D axis-symmetric model that simulates the water saturation of the bentonite under a constant thermal gradient; the transport of solutes; and, the geochemical reactions observed in the bentonite blocks. Two cases have been modelled, one considering the highest temperature reached by the bentonite (at 3 m depth in the borehole, where temperatures of 130 and 85 deg C have been recorded near the copper tube and near the granitic host rock, respectively) and the other case assuming a constant temperature of 25 deg C, representing the upper part of borehole, where the bentonite has not been heated. In the LOT A2 test, the initial partially saturated bentonite becomes progressively water saturated, due to the injection of Aespoe granitic groundwater at granite - bentonite interface. The transport of solutes during the bentonite water saturation stage is believed to be controlled by water uptake from the surrounding groundwater to the wetting front and, additionally, in the case of heated bentonite, by a cyclic evaporation

  9. Modelling Feature Interaction Patterns in Nokia Mobile Phones using Coloured Petri Nets and Design/CPN

    DEFF Research Database (Denmark)

    Lorentsen, Louise; Tuovinen, Antti-Pekka; Xu, Jianli

    2002-01-01

    This paper describes the first results of a project on modelling of important feature interaction patterns of Nokia mobile phones using Coloured Petri Nets. A modern mobile phone supports many features: voice and data calls, text messaging, personal information management (phonebook and calendar....... In this paper, we look at the problem of feature interaction in the user interface of Nokia mobile phones. We present a categorization of feature interactions and describe our approach to the modelling of feature interactions using Coloured Petri Nets (CP-nets or CPN). The CPN model is extended...

  10. Geochemical modeling of iron, sulfur, oxygen and carbon in a coastal plain aquifer

    Science.gov (United States)

    Brown, C.J.; Schoonen, M.A.A.; Candela, J.L.

    2000-01-01

    Fe(III) reduction in the Magothy aquifer of Long Island, NY, results in high dissolved-iron concentrations that degrade water quality. Geochemical modeling was used to constrain iron-related geochemical processes and redox zonation along a flow path. The observed increase in dissolved inorganic carbon is consistent with the oxidation of sedimentary organic matter coupled to the reduction of O2 and SO4/2- in the aerobic zone, and to the reduction of SO4/2- in the anaerobic zone; estimated rates of CO2 production through reduction of Fe(III) were relatively minor by comparison. The rates of CO2 production calculated from dissolved inorganic carbon mass transfer (2.55 x 10-4 to 48.6 x 10-4 mmol 1-1 yr-1) generally were comparable to the calculated rates of CO2 production by the combined reduction of O2, Fe(III) and SO4/2- (1.31 x 10-4 to 15 x 10-4 mmol 1-1 yr-1). The overall increase in SO4/2- concentrations along the flow path, together with the results of mass-balance calculations, and variations in ??34S values along the flow path indicate that SO4/2- loss through microbial reduction is exceeded by SO4/2- gain through diffusion from sediments and through the oxidation of FeS2. Geochemichal and microbial data on cores indicate that Fe(III) oxyhydroxide coatings on sediment grains in local, organic carbon- and SO4/2- -rich zones have localized SO4/2- -reducing zones in which the formation of iron disulfides been depleted by microbial reduction and resulted in decreases dissolved iron concentrations. These localized zones of SO4/2- reduction, which are important for assessing zones of low dissolved iron for water-supply development, could be overlooked by aquifer studies that rely only on groundwater data from well-water samples for geochemical modeling. (C) 2000 Elsevier Science B.V.Fe(III) reduction in the Magothy aquifer of Long Island, NY, results in high dissolved-iron concentrations that degrade water quality. Geochemical modeling was used to constrain iron

  11. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110462 Chen Furong(Anhui Institute of Geological Survey,Hefei 230001,China)Ore-Search Prospects of Gold and Tungsten Geochemical Anomalies in Ningdun Area,Anhui Province(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,34(2),2010,p.150-153,5 illus.,2 tables,6 refs.)Key words:gold ores,tungsten ores,geochemical exploration,AnhuiGeochemical anomalies of gold and tungsten in Ningdun area are dominated by the element association of Au-As-W-Bi.These anomalies are well coincident with

  12. The CAFE model: A net production model for global ocean phytoplankton

    Science.gov (United States)

    Silsbe, Greg M.; Behrenfeld, Michael J.; Halsey, Kimberly H.; Milligan, Allen J.; Westberry, Toby K.

    2016-12-01

    The Carbon, Absorption, and Fluorescence Euphotic-resolving (CAFE) net primary production model is an adaptable framework for advancing global ocean productivity assessments by exploiting state-of-the-art satellite ocean color analyses and addressing key physiological and ecological attributes of phytoplankton. Here we present the first implementation of the CAFE model that incorporates inherent optical properties derived from ocean color measurements into a mechanistic and accurate model of phytoplankton growth rates (μ) and net phytoplankton production (NPP). The CAFE model calculates NPP as the product of energy absorption (QPAR), and the efficiency (ϕμ) by which absorbed energy is converted into carbon biomass (CPhyto), while μ is calculated as NPP normalized to CPhyto. The CAFE model performance is evaluated alongside 21 other NPP models against a spatially robust and globally representative set of direct NPP measurements. This analysis demonstrates that the CAFE model explains the greatest amount of variance and has the lowest model bias relative to other NPP models analyzed with this data set. Global oceanic NPP from the CAFE model (52 Pg C m-2 yr-1) and mean division rates (0.34 day-1) are derived from climatological satellite data (2002-2014). This manuscript discusses and validates individual CAFE model parameters (e.g., QPAR and ϕμ), provides detailed sensitivity analyses, and compares the CAFE model results and parameterization to other widely cited models.

  13. Geochemical Modeling of Evaporation Processes on Mars: Insight From the Sedimentary Record at Meridiani Planum

    Science.gov (United States)

    Tosca, N. J.; McLennan, S. M.

    2004-12-01

    The Opportunity rover's analysis of an impure evaporite component present in the Martian sedimentary record reveals a unique geochemical system. The evaporation of basaltic weathering fluids is a process which is rare on Earth, but is likely to have played a major role in the formation of sedimentary rocks at Meridiani Planum. Adequately modeling the evaporation processes in this system must involve adding additional components to current thermodynamic models, namely Fe(II) and Fe(III). The goals of this study are to: (1) develop a thermodynamic database suitable for modeling evaporation of basaltic weathering fluids in the Meridiani system and (2) to apply the model to experimental fluid data obtained in our laboratory from weathering synthetic Martian basalt, which will allow for the testing of hypotheses related to the geochemical evolution of the Meridiani site. The evaporation of these fluids is simulated using an expanded version of the Harvie-Moller-Weare model which employs Pitzer's ion interaction approach in calculating activity coefficients in high ionic strength solutions. This model has been expanded using recent data to include Fe(II) and Fe(III). Although a full set of experimentally-derived data allowing the inclusion of Fe(III) into such models is not yet available, an adequate set of interaction parameters was built, based on viable assumptions and substitutions using analog data (e.g., Al3+, Ga3+, Cr3+). The accuracy of the thermodynamic model in predicting Fe(II) and Fe(III) activities in a multi-component system can be assessed. This is accomplished by comparing calculated Eh values (proportional to aFe2+/aFe3+) to those measured in the field from high ionic strength acid mine waters containing all of the relevant components of the model. The agreement between calculated and observed values suggests that the model calculations are adequate for reaction path calculations. New thermodynamic data for several Fe(II) and/or Fe(III) containing

  14. Geomechanical/Geochemical Modeling Studies Conducted within theInternational DECOVALEX Project

    Energy Technology Data Exchange (ETDEWEB)

    Birkholzer, J.T.; Rutqvist, J.; Sonnenthal, E.L.; Barr, D.; Chijimatsu, M.; Kolditz, O.; Liu, Q.; Oda, Y.; Wang, W.; Xie, M.; Zhang, C.

    2005-10-19

    The DECOVALEX project is an international cooperative project initiated by SKI, the Swedish Nuclear Power Inspectorate, with participation of about 10 international organizations. The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled thermo-hydro-mechanical-chemical (THMC) processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. One of the research tasks, initiated in 2004 by the U.S. Department of Energy (DOE), addresses the long-term impact of geomechanical and geochemical processes on the flow conditions near waste emplacement tunnels. Within this task, four international research teams conduct predictive analysis of the coupled processes in two generic repositories, using multiple approaches and different computer codes. Below, we give an overview of the research task and report its current status.

  15. A model of the geochemical and physical fluctuations of the lava lake at Erebus volcano, Antarctica

    Science.gov (United States)

    Molina, Indira; Burgisser, Alain; Oppenheimer, Clive

    2015-12-01

    Erebus volcano, Antarctica, exhibits periodical surface fluctuations of both geochemical and physical nature. Modeling the physics driving the lake oscillation is a challenge, even with a relatively simple theoretical framework. We present a quantitative analysis that aims to reconcile both lake level and gas geochemical cycles. Our model is based on the assumption that the periodicity is caused by the regular release of magma batches and/or core annular flow that have a fixed volume of melt and ascend and degas in equilibrium. Results suggest that cycles are not caused by the mixing between magma residing in the lake and a deep magma but by two distinct deep sources that rise separately. These sources of bubbly magma come from at most 2-3 km depth and rise buoyantly. Individual batches detach from the rising magmas at depths of 20-250 m. The two batch types can coexist in a single conduit up to a depth of ~ 30 m, above which they rise alternately to release respectively 19 and 23 kg/s of gas at the lake surface every 10 min. The temperature of the descending flow is between 890 and 950 °C, which is roughly 100 °C colder than the ascending currents. Batch pairs have shapes likely constrained by the conduit width. Regardless of their shapes, the pairs reach very high porosities near the surface and have diameters of 4-14 m that are consistent with video observations showing spreading waves at the lake surface. The alternating arrival of these large batches suggests a lava lake mostly filled with gas-rich magma.

  16. Geochemical modelling of groundwater evolution and residence time at the Haestholmen site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy, Helsinki (Finland); Leino- Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    2001-01-01

    An understanding of the geochemical evolution of groundwater is an essential part of the performance assessment and safety analysis of the geological final disposal of radioactive waste. The performance of technical barriers and migration of possibly released radionuclides depend on the geochemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions that control chemical conditions in groundwater. The objective of this study is to interpret the processes and factors that control the hydrogeochemistry, such as pH and redox conditions. A model of the hydrogeochemical progress in different parts of the crystalline bedrock at Haestholmen has been created and the significance of geochemical reactions and groundwater mixing along different flow paths calculated. Long term hydrodynamics have also been evaluated. The interpretation and modelling are based on water samples (64 altogether) obtained from precipitation, the Baltic Sea, the soil layer, shallow wells in the bedrock, and 14 deep boreholes in the bedrock for which a comprehensive data set on dissolved chemical species and isotopes was available. Some analyses of dissolved gases and their isotopic measurements were also utilised. The data covers the bedrock at Haestholmen to a depth of 1000 m. The results from groundwater chemistry, isotopes, petrography, hydrogeology of the site, geomicrobial studies, and PCA and speciation calculations were used to evaluate evolutionary processes at the site. The geochemical interpretation of water-rock interaction, isotope-chemical evolution ({delta}{sup 13}C and {delta}{sup 34}S) and mixing of palaeo-water types were approached by mass-balance calculations (NETPATH). Reaction-path calculations (EQ3/6) were used to verify the thermodynamic feasibility of the reaction models obtained. The interpretation and calculation of hydrochemical data from Haestholmen suggest that changes in external conditions, such as glaciation

  17. A Petri Net-Based Software Process Model for Developing Process-Oriented Information Systems

    Science.gov (United States)

    Li, Yu; Oberweis, Andreas

    Aiming at increasing flexibility, efficiency, effectiveness, and transparency of information processing and resource deployment in organizations to ensure customer satisfaction and high quality of products and services, process-oriented information systems (POIS) represent a promising realization form of computerized business information systems. Due to the complexity of POIS, explicit and specialized software process models are required to guide POIS development. In this chapter we characterize POIS with an architecture framework and present a Petri net-based software process model tailored for POIS development with consideration of organizational roles. As integrated parts of the software process model, we also introduce XML nets, a variant of high-level Petri nets as basic methodology for business processes modeling, and an XML net-based software toolset providing comprehensive functionalities for POIS development.

  18. Bigraphical Nets

    Directory of Open Access Journals (Sweden)

    Ian Mackie

    2013-02-01

    Full Text Available Interaction nets are a graphical model of computation, which has been used to define efficient evaluators for functional calculi, and specifically lambda calculi with patterns. However, the flat structure of interaction nets forces pattern matching and functional behaviour to be encoded at the same level, losing some potential parallelism. In this paper, we introduce bigraphical nets, or binets for short, as a generalisation of interaction nets using ideas from bigraphs and port graphs, and we present a formal notation and operational semantics for binets. We illustrate their expressive power by examples of applications.

  19. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>20081182 Chen Guoguang(China University of Geosciences,Wuhan 430074,China);Zhou Guohua Eco-Geochemical Assessment Based On Geosciences(Resources Survey & Environment,ISSN1671-4814,CN32-1640/N,28(2),2007,p.79-84,2 tables,6 refs.)Key words:regional geochemical

  20. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131784 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China);Lei Yingping Geochemical Characteristics and Metallogenic Prospecting Areas in Yunkai Area,Guangxi(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,36

  1. Alligator Rivers Analogue project. Geochemical modelling of present-day groundwaters. Final Report - Volume 12

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, D. A. [The John Hopkins Univ, Dept of Earth and Planetary Sciences, Baltimore (United States)

    1992-12-31

    The main purpose of this report is to summarize geochemical modeling studies of the present-day Koongarra groundwaters. Information on the present-day geochemistry and geochemical processes at Koongarra forms a basis for a present-day analogue for nuclear waste migration. The present-day analogue is built on studies of the mineralogy and petrology of the Koongarra deposit, and chemical analyses of present-day groundwaters from the deposit. The overall approach taken in the present study has been to carry out a series of aqueous speciation and state of saturation calculations, including chemical mass transfer calculations, to address the possible control over the chemistry of the present-day for the groundwaters at Koongarra. The most important implication of the present study for the migration of radionuclides is the strong role played by the water-rock interactions, both above and below the water table, influencing the overall chemical evolution of the groundwaters. Thus, the results show that the chemical evolution of waters is strongly controlled by the initial availability of CO{sub 2} and the mineral assemblage encountered, which together determine the major element evolution of the waters by controlling the pH. The relative rates of evolution of the pH and the oxidation state of the groundwaters are also critical to the mobility of uranium. The shallow Koongarra waters are sufficiently oxidising that they can dissolve and transport uranium even under acidic conditions. Under the more reducing condition of the deep groundwaters, is the pH level that permits uranium transport as carbonate complexes. However, if the oxidation state decreases to much lower levels, it would be expected that uranium become immobile. All the speciation and state of saturation calculations carried out in the present study are available from the author, on request 22 refs., 7 tabs., 18 figs.

  2. Modelling of leaching and geochemical processes in an aged MSWIBA subbase layer

    Energy Technology Data Exchange (ETDEWEB)

    Bendz, David; Suer, Pascal; Sloot, Hans van der; Kosson, David; Flyhammar, Peter

    2009-07-15

    In a previous project, the accumulated effects of leaching and aging in a subbase layer of bottom ash in a test road were investigated. The test road were constructed in 1987 in Linkoeping, Sweden, and was in use until the start of the Vaendoera Q4-241 study in September 2003. The overall objective of the present study is to bring the evaluation of the previous project (Q4-241) further by taking advantage of the existing data, perform complementary laboratory experiments on four composite samples reflecting different degree of exposure to atmosphere and leaching. The specific objectives were to investigate: (i) what processes and mineral phases that govern leaching of macro- and trace elements and DOC in the bottom ash after 16 years (1987- 2003) of aging under field conditions. (ii) how the hydrologic conditions, infiltration of water and leachate production has evolved with time. The following tests were performed on the composite samples: pH-stat test, column test, Fe/Al oxide extraction and TOC fractioning. Geochemical and hydrological modelling where performed with LeachXS/Orchestra and Hydrus 2-D. Daily precipitation data from the Swedish Meteorological and Hydrological Institute (SMHI) from the Malmslaett (Linkoeping) measurement station was used in the hydrological modelling of January 1988 to the 1st of september 2003. The hydraulic modeling results show that the bottom ash subbase layer endure seasonal wet and dry cycles. The results confirm that, depending on the boundary conditions along the shoulders the capillary potential may drive moisture either in or out of the road body. The water retention parameters for bottom ash were crucial in the hydraulic modeling and the capillary forces in bottom ash were found to be significant with a water retention curve close to silt. This explains the observed depletion of easily soluble salts in the test road. The results showed that the accumulated LS ratio for the bottom ash subbase layer reached about LS:10 in

  3. Geochemical modeling of fluid-fluid and fluid-mineral interactions during geological CO2 storage

    Science.gov (United States)

    Zhu, C.; Ji, X.; Lu, P.

    2013-12-01

    The long time required for effective CO2 storage makes geochemical modeling an indispensable tool for CCUS. One area of geochemical modeling research that is in urgent need is impurities in CO2 streams. Permitting impurities, such as H2S, in CO2 streams can lead to potential capital and energy savings. However, predicting the consequences of co-injection of CO2 and impurities into geological formations requires the understanding of the phase equilibrium and fluid-fluid interactions. To meet this need, we developed a statistical associating fluid theory (SAFT)-based equation of state (EOS) for the H2S-CO2-H2O-NaCl system at 373.15 dew pressures decrease with increasing H2S content, while the mass density increases at low pressures and decreases at high pressures. Furthermore, the EoS can be incorporated into reservoir simulators so that the dynamic development of mixed fluid plumes in the reservoir can be simulated. Accurate modeling of fluid-mineral interactions must confront unresolved uncertainties of silicate dissolution - precipitation reaction kinetics. Most prominent among these uncertainties is the well-known lab-field apparent discrepancy in dissolution rates. Although reactive transport models that simulate the interactions between reservoir rocks and brine, and their attendant effects on porosity and permeability changes, have proliferated, whether these results have acceptable uncertainties are unknown. We have conducted a series of batch experiments at elevated temperatures and numerical simulations of coupled dissolution and precipitation reactions. The results show that taking into account of reaction coupling is able to reduce the gap between the field and lab rates by about two orders of magnitude at elevated temperatures of 200-300 oC. Currently, we are using Si isotopes as a new tool to unravel the coupled reactions in ambient temperature laboratory experiments. These new experimental data, together with coupled reactive mass transport modeling

  4. Modelling of phase change materials in the Toronto SUI net zero energy house using TRNSYS

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, O.; Fung, A.; Zhang, D. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Mechanical and Industrial Engineering

    2008-08-15

    In the context of building applications, phase change materials (PCM), can be defined as any heat storage material that can absorb a large amount of thermal energy while undergoing a change in phase, such as from a solid to a liquid phase. The incorporation of PCM into the building envelope can enhance occupant comfort through the reduction of indoor temperature fluctuations. It has also been shown to cause a decrease in the overall energy consumption associated with the heating and cooling of buildings. This paper extended the analysis of the impact of using PCM, which has traditionally focused on homes of ordinary construction, to incorporate low to zero energy homes using a model of the Toronto net zero energy house developed in TRNSYS. The paper provided a description of the TRNSYS model/methodology, with reference to the wall layer used in the net zero energy house, and model of the layout of the net zero energy house in TRYNSYS. The TRYNSYS/type 204 PCM component was also presented along with the simulation results in terms of the temperature profile of the third floor of the net zero energy house on a typical winter day with varying PCM concentrations; the temperature profile of the third floor of the net zero energy house on a typical summer day with varying PCM concentrations; yearly heating/cooling load requirements of the net zero energy house for a variety of thermal mass used; temperature profile of the third floor of the net zero energy house on a typical summer day when PCM and concrete slab was used; yearly temperature profile of the third floor of the net zero energy house, illustrating the impact of using PCM; and the yearly heating/cooling load of the net zero energy house as the concentration of PCM was varied. It was concluded that the use of building integrated PCM can reduce temperature fluctuations considerably in the summer but only slightly in the winter. 16 refs., 1 tab., 8 figs.

  5. A review of the hydrogeologic-geochemical model for Cerro Prieto

    Science.gov (United States)

    Lippmann, M.J.; Truesdell, A.H.; Halfman-Dooley, S. E.; Mañónm, A.

    1991-01-01

    With continued exploitation of the Cerro Prieto, Mexico, geothermal field, there is increasing evidence that the hydrogeologic model developed by Halfman and co-workers presents the basic features controlling the movement of geothermal fluids in the system. In mid-1987 the total installed capacity at Cerro Prieto reached 620 MWc, requiring a large rate of fluid production (more than 10,500 tonnes/hr of a brine-steam mixture; August 1988). This significant mass extraction has led to changes in reservoir thermodynamic conditions and in the chemistry of the produced fluids. Pressure drawdown has caused an increase in cold water recharge in the southern and western edges of the field, and local and general reservoir boiling in parts of the geothermal system. After reviewing the hydrogeologic and geochemical models of Cerro Prieto, the exploitation-induced cold water recharge and reservoir boiling (and plugging) observed in different areas of the field, are discussed and interpreted on the basis of these models and schematic flow models that describe the hydrogeology. ?? 1991.

  6. Reliability modelling of repairable systems using Petri nets and fuzzy Lambda-Tau methodology

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, J.; Odoom, E.R

    2001-07-01

    A methodology is developed which uses Petri nets instead of the fault tree methodology and solves for reliability indices utilising fuzzy Lambda-Tau method. Fuzzy set theory is used for representing the failure rate and repair time instead of the classical (crisp) set theory because fuzzy numbers allow expert opinions, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into the system model. Petri nets are used because unlike the fault tree methodology, the use of Petri nets allows efficient simultaneous generation of minimal cut and path sets.

  7. Modelling and simulation of signal transductions in an apoptosis pathway by using timed Petri nets

    Indian Academy of Sciences (India)

    Chen Li; Qi-Wei Ge; Mitsuru Nakata; Hiroshi Matsuno; Satoru Miyano

    2007-01-01

    This paper first presents basic Petri net components representing molecular interactions and mechanisms of signalling pathways, and introduces a method to construct a Petri net model of a signalling pathway with these components. Then a simulation method of determining the delay time of transitions, by using timed Petri nets – i.e. the time taken in firing of each transition – is proposed based on some simple principles that the number of tokens flowed into a place is equivalent to the number of tokens flowed out. Finally, the availability of proposed method is confirmed by observing signalling transductions in biological pathways through simulation experiments of the apoptosis signalling pathways as an example.

  8. Geochemical modeling of diagenetic reactions in Snorre Field reservoir sandstones: a comparative study of computer codes

    Directory of Open Access Journals (Sweden)

    Marcos Antonio Klunk

    Full Text Available ABSTRACTDiagenetic reactions, characterized by the dissolution and precipitation of minerals at low temperatures, control the quality of sedimentary rocks as hydrocarbon reservoirs. Geochemical modeling, a tool used to understand diagenetic processes, is performed through computer codes based on thermodynamic and kinetic parameters. In a comparative study, we reproduced the diagenetic reactions observed in Snorre Field reservoir sandstones, Norwegian North Sea. These reactions had been previously modeled in the literature using DISSOL-THERMAL code. In this study, we modeled the diagenetic reactions in the reservoirs using Geochemist's Workbench (GWB and TOUGHREACT software, based on a convective-diffusive-reactive model and on the thermodynamic and kinetic parameters compiled for each reaction. TOUGHREACT and DISSOL-THERMAL modeling showed dissolution of quartz, K-feldspar and plagioclase in a similar temperature range from 25 to 80°C. In contrast, GWB modeling showed dissolution of albite, plagioclase and illite, as well as precipitation of quartz, K-feldspar and kaolinite in the same temperature range. The modeling generated by the different software for temperatures of 100, 120 and 140°C showed similarly the dissolution of quartz, K-feldspar, plagioclase and kaolinite, but differed in the precipitation of albite and illite. At temperatures of 150 and 160°C, GWB and TOUGHREACT produced different results from the DISSOL-THERMAL, except for the dissolution of quartz, plagioclase and kaolinite. The comparative study allows choosing the numerical modeling software whose results are closer to the diagenetic reactions observed in the petrographic analysis of the modeled reservoirs.

  9. Distinguishing Environment and System in Coloured Petri Net Models of Reactive Systems

    DEFF Research Database (Denmark)

    Tjell, Simon

    2007-01-01

    This paper introduces and formally defines the environment-and-system-partitioned property for behavioral models of reactive systems expressed in the formal modeling language Coloured Petri Net. The purpose of the formalization is to make it possible to automatically validate any CPN model with r...... code-generation from models. A prototypical tool has been implemented for performing the structural analysis of Coloured Petri Net models and the principles of this tool is described. The aim of the paper is to make the guidelines and their formalized definitions along with a proof...

  10. Integration of Genome-Scale Metabolic Nodels of Iron-Reducing Bacteria With Subsurface Flow and Geochemical Reactive Transport Models

    Science.gov (United States)

    Scheibe, T. D.; Mahadevan, R.; Fang, Y.; Garg, S.; Long, P. E.; Lovley, D. M.

    2008-12-01

    Several field and laboratory experiments have demonstrated that the growth and activity of iron-reducing bacteria can be stimulated in many subsurface environments by amendment of groundwater with a soluble electron donor. Under strong iron-reducing conditions, these organisms mediate reactions that can impact a wide range of subsurface contaminants including chlorinated hydrocarbons, metals, and radionuclides. Therefore there is strong interest in in-situ bioremediation as a potential technology for cleanup of contaminated aquifers. To evaluate and design bioremediation systems, as well as to evaluate the viability of monitored natural attenuation as an alternative, quantitative models of biogeochemically reactive transport are needed. To date, most such models represent microbial activity in terms of kinetic rate (e.g., Monod- type) formulations. Such models do not account for fundamental changes in microbial functionality (such as utilization of alternative respiratory pathways) that occur as the result of spatial and temporal variations in the geochemical environment experienced by microorganisms. Constraint-based genome-scale in silico models of microbial metabolism present an alternative to simplified rate formulations that provide flexibility to account for changes in microbial function in response to local geochemical conditions. We have developed and applied a methodology for coupling a constraint-based in silico model of Geobacter sulfurreducens with a conventional model of groundwater flow, transport, and geochemical reaction. Two uses of the in silico model are tested: 1) incorporation of modified microbial growth yield coefficients based on the in silico model, and 2) variation of reaction rates in a reactive transport model based on in silico modeling of a range of local geochemical conditions. Preliminary results from this integrated model will be presented.

  11. The Role of Geochemical Modeling in Predicting Quality Evolution of Acid Mine Drainage

    Directory of Open Access Journals (Sweden)

    Andrea Šlesárová

    2004-12-01

    Full Text Available In recent years the massive reduction of raw materials production brings a wide scale of problems. Among the most frequent exposes of mining activities belong besides old spoil heaps and sludge lagoons, also the drainage of acidic and highly mineralized mine waters known as “the Acid Mine Drainage” (thereinafter AMD from old mine workings. The acid mine drainage presents to the surrounding environment a massive problem. These waters are toxic to the plant and animal life, including fishes and aquatic insects. The primary control of the drainage pH and the metal content is the exposure of sulphide minerals to weathering, the availability of atmospheric oxygen, and the sensitivity of non-sulphide minerals to buffer acidity. A geochemical modeling software is increasingly used to solve evolution of the complex chemical systems such as the interaction of acid mine drainage with wall rocks, migration of AMD components. Beyond the better computer facilities it allows to study of thermodynamic properties substances and to enlarge thermodynamic databases. A model is a simplified version of reality based on its observation and experiments. A goal of the modeling process is the tendency to better understand processes taking place inside of the system, the attempt to assume the system’s behaviour in the future or to predict the effect of changed conditions in the system’s environment on the system itself.

  12. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091835 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Zhuang Guangmin The Cd Geochemical Province in the Source Area of the Yangtze River and the Output Fluxes of Cd for Its Major Water Systems(Earth Science Frontiers,ISSN1005-2321,CN11-3370/P,15(5),2008,p.203-211,5 illus.,5 tables,25 refs.,with English abstract)Key words:cadmium,geochemical province,Qinghai-Tibetan Plateau20091836 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Yang Zhongfang A New Round of Global Geochemical

  13. Predicting species’ tolerance to salinity and alkalinity using distribution data and geochemical modelling: a case study using Australian grasses

    Science.gov (United States)

    Saslis-Lagoudakis, C. Haris; Hua, Xia; Bui, Elisabeth; Moray, Camile; Bromham, Lindell

    2015-01-01

    Background and Aims Salt tolerance has evolved many times independently in different plant groups. One possible explanation for this pattern is that it builds upon a general suite of stress-tolerance traits. If this is the case, then we might expect a correlation between salt tolerance and other tolerances to different environmental stresses. This association has been hypothesized for salt and alkalinity tolerance. However, a major limitation in investigating large-scale patterns of these tolerances is that lists of known tolerant species are incomplete. This study explores whether species’ salt and alkalinity tolerance can be predicted using geochemical modelling for Australian grasses. The correlation between taxa found in conditions of high predicted salinity and alkalinity is then assessed. Methods Extensive occurrence data for Australian grasses is used together with geochemical modelling to predict values of pH and electrical conductivity to which species are exposed in their natural distributions. Using parametric and phylogeny-corrected tests, the geochemical predictions are evaluated using a list of known halophytes as a control, and it is determined whether taxa that occur in conditions of high predicted salinity are also found in conditions of high predicted alkalinity. Key Results It is shown that genera containing known halophytes have higher predicted salinity conditions than those not containing known halophytes. Additionally, taxa occurring in high predicted salinity tend to also occur in high predicted alkalinity. Conclusions Geochemical modelling using species’ occurrence data is a potentially useful approach to predict species’ relative natural tolerance to challenging environmental conditions. The findings also demonstrate a correlation between salinity tolerance and alkalinity tolerance. Further investigations can consider the phylogenetic distribution of specific traits involved in these ecophysiological strategies, ideally by

  14. Model-based analysis of the role of biological, hydrological and geochemical factors affecting uranium bioremediation.

    Science.gov (United States)

    Zhao, Jiao; Scheibe, Timothy D; Mahadevan, R

    2011-07-01

    Uranium contamination is a serious concern at several sites motivating the development of novel treatment strategies such as the Geobacter-mediated reductive immobilization of uranium. However, this bioremediation strategy has not yet been optimized for the sustained uranium removal. While several reactive-transport models have been developed to represent Geobacter-mediated bioremediation of uranium, these models often lack the detailed quantitative description of the microbial process (e.g., biomass build-up in both groundwater and sediments, electron transport system, etc.) and the interaction between biogeochemical and hydrological process. In this study, a novel multi-scale model was developed by integrating our recent model on electron capacitance of Geobacter (Zhao et al., 2010) with a comprehensive simulator of coupled fluid flow, hydrologic transport, heat transfer, and biogeochemical reactions. This mechanistic reactive-transport model accurately reproduces the experimental data for the bioremediation of uranium with acetate amendment. We subsequently performed global sensitivity analysis with the reactive-transport model in order to identify the main sources of prediction uncertainty caused by synergistic effects of biological, geochemical, and hydrological processes. The proposed approach successfully captured significant contributing factors across time and space, thereby improving the structure and parameterization of the comprehensive reactive-transport model. The global sensitivity analysis also provides a potentially useful tool to evaluate uranium bioremediation strategy. The simulations suggest that under difficult environments (e.g., highly contaminated with U(VI) at a high migration rate of solutes), the efficiency of uranium removal can be improved by adding Geobacter species to the contaminated site (bioaugmentation) in conjunction with the addition of electron donor (biostimulation). The simulations also highlight the interactive effect of

  15. Geochemical modelling of groundwater evolution and residence time at the Kivetty site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy, Helsinki (Finland); Leino-Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    1998-12-01

    An understanding of the geochemical evolution of groundwater is an essential part of the performance assessment and safety analysis of the final disposal of radioactive waste into the bedrock. The performance of technical barriers and migration of possibly released radionuclides depend on chemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions which control chemical conditions in groundwater. The objective of this study is to interpret the processes and factors which control the hydrogeochemistry, such as pH and redox conditions. A model of the hydrogeochemical progress in different parts of the bedrock at Kivetty has been created and the significance of chemical reactions along different flowpaths calculated. Long term hydrodynamics have also been evaluated. The interpretation and modelling are based on groundwater samples (38 altogether) obtained from the soil layer, shallow wells in the bedrock, and five deep multi-packered boreholes (KRI-KR5) in the bedrock for which a comprehensive data set on dissolved chemical species and isotopes was available. Some analyses of dissolved gases and their isotopic measurements were also utilised. The data covers the bedrock at Kivetty to a depth of 850m. The results from groundwater chemistry, isotopes, petrography, hydrogeology of the site, geomicrobial studies, and PCA and speciation calculations were used in the evaluation of evolutionary processes at the site. The geochemical interpretation of water-rock interaction, isotope-chemical evolution and C-14 age calculations of groundwater was given a mass-balance approach (NETPATH). Reaction-path calculations (EQ3/6) were used to verify the thermodynamic feasibility of the reaction models obtained. The hydrogeochemistry of Kivetty is characterised by evolution from low-saline-carbonate-rich recharge water towards Na-Ca-Cl-type water. The salinity remains low. The most important changes in the chemistry of the

  16. The Role of Volcanic Sour Gas on the Alteration of Martian Basalt: Insights from Geochemical Modeling

    Science.gov (United States)

    Berger, G.; Treguier, E.; D'Uston, C.; Pinet, P.; Toplis, M. J.

    2008-03-01

    We assess the chemical constraints of the alteration of basaltic material by a cold aqueous phase under atmospheric sour gas containing SO3. Secondary chemistry and mineralogy are calculated by a geochemical simulator and compared to MER data.

  17. MODELING AND SIMULATION OF QUEUE WAITING THROUGH THE CONCEPT OF PETRI NETS

    Directory of Open Access Journals (Sweden)

    Emilija KAMCEVA

    2011-08-01

    Full Text Available Petri Nets-PN are a graphical formalism which is gaining popularity in recent years as a tool in Matlab for the representation of complex logical interactions among physical components or activities in a system. This notes are devoted to introduce the formalism of Petri nets with particular emphasis on the application of the methodology in the area of the performance and reliability modelling and analysis of systems. A technique is presented whereby queueing network models and generalized stochastic Petri nets are combined in such a way as to exploit the best features of both modeling techniques. The resulting hierarchical modeling approach is useful in the solution of complex models of system behavior.

  18. A nonlinear programming optimization model to maximize net revenue in cheese manufacture.

    Science.gov (United States)

    Papadatos, A; Berger, A M; Pratt, J E; Barbano, D M

    2002-11-01

    A nonlinear programming optimization model was developed to maximize net revenue in cheese manufacture and is described in this paper. The model identifies the optimal mix of milk resources together with the types of cheeses and co-products that maximize net revenue. It works in Excel while it takes the data specified by the user from a user-friendly interface created in Access. The user can specify any number of resources, cheese types, and co-products. To demonstrate the capabilities of the model, we determined the impact of variation in milk price and composition in the period 1998 to 2000 on the optimal mix of resources and optimal type of co-product for Cheddar and low-moisture, part-skim Mozzarella. It was also desired to determine the impact of variation in protein content of nonfat dry milk (NDM) on net revenue, and examine the effect of reconstitution of NDM with water versus milk on net revenue. The optimal mix of resources and the net revenue markedly varied as milk resource prices and composition varied. The net revenue for Mozzarella was much higher than for Cheddar when the price of cream was high. Cheese plants that did not optimize the use of resources in response to variations in prices and composition missed a significant profit opportunity. Whey powder was more profitable than 34% whey protein concentrate and lactose in most months. The use of high-protein NDM led to an appreciable increase in net revenue. When the value of the nonfat portion of raw milk was high, reconstitution of NDM with water rather than milk markedly raised net revenue.

  19. A Mean-Value Analysis of Stochastic Petri Net Models of Slotted Rings

    NARCIS (Netherlands)

    Coyle, Andrew; Haverkort, Boudewijn R.; Henderson, William; Pearce, Charles E.M.

    1996-01-01

    In this paper, we analyse Stochastic Petri Net (SPN) models of slotted-ring networks. We show that a simple SPN model of a slotted-ring network, which exhibits a product-form solution, yields similar results to a more detailed SPN model that has to be analysed by numerical means. Furthermore, we dem

  20. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152642 Baoyinwuliji(Inner Mongolia Institute of Geological Survey,Hohhot 010020,China);Zhao Wentao Geochemical Anomaly and Metallogenic Potential of the Naomugengsumu Lithium Mineralization Area in Inner Mongolia(Geology and Resources,ISSN1671

  1. Experimental Investigation and Simplistic Geochemical Modeling of CO2 Mineral Carbonation Using the Mount Tawai Peridotite

    Directory of Open Access Journals (Sweden)

    Omeid Rahmani

    2016-03-01

    Full Text Available In this work, the potential of CO2 mineral carbonation of brucite (Mg(OH2 derived from the Mount Tawai peridotite (forsterite based (Mg2SiO4 to produce thermodynamically stable magnesium carbonate (MgCO3 was evaluated. The effect of three main factors (reaction temperature, particle size, and water vapor were investigated in a sequence of experiments consisting of aqueous acid leaching, evaporation to dryness of the slurry mass, and then gas-solid carbonation under pressurized CO2. The maximum amount of Mg converted to MgCO3 is ~99%, which occurred at temperatures between 150 and 175 °C. It was also found that the reduction of particle size range from >200 to <75 µm enhanced the leaching rate significantly. In addition, the results showed the essential role of water vapor in promoting effective carbonation. By increasing water vapor concentration from 5 to 10 vol %, the mineral carbonation rate increased by 30%. This work has also numerically modeled the process by which CO2 gas may be sequestered, by reaction with forsterite in the presence of moisture. In both experimental analysis and geochemical modeling, the results showed that the reaction is favored and of high yield; going almost to completion (within about one year with the bulk of the carbon partitioning into magnesite and that very little remains in solution.

  2. Geochemical inputs for hydrological models of deep-lying sedimentary units: Loss of mineral hydration water

    Science.gov (United States)

    Graf, D. L.; Anderson, D. E.

    1981-12-01

    Hydrological models that treat phenomena occurring deep in sedimentary piles, such as petroleum maturation and retention of chemical and radioactive waste, may require time spans of at least several million years. Many input quantities classically treated as constants will be variables on this time scale. Models sophisticated enough to include transport contributions from such processes as chemical diffusion, mineral dehydration and shale membrane behavior require considerable knowledge about regional geological history as well as the pertinent mineralogical and geochemical relationships. Simple dehydrations such as those of gypsum and halloysite occur at sharply-defined temperatures but, as with all mineral dehydration reactions, the equilibrium temperature is strongly dependent on the pore-fluid salinity and degree of overpressuring encountered in the subsurface. The dehydrations of analcime and smectite proceed by reactions involving other sedimentary minerals. The smectite reaction is crystallographically complex, yielding a succession of mixed-layered illite/smectites, and on the U.S.A. Gulf of Mexico coast continues over several million years at a particular stratigraphic interval.

  3. Derivation of in situ opalinus clay porewater compositions from experimental and geochemical modelling studies

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, M.H.; Baeyens, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-12-01

    Many countries are considering argillaceous sedimentary rocks as potential formations for the disposal of high level radioactive waste. One of the main attractions of such formations from a waste management viewpoint are their generally low groundwater flow rates. However, porewater chemistry constitutes an important basic data set for performance assessment studies and the low transmissivities often mean that it is very difficult, or even impossible, to obtain good in situ water samples. This report describes procedures based on physico-chemical characterisation of whole rock samples and geochemical modelling which were developed as an additional tool for determining porewater compositions in low porosity/permeability clay rich systems. The methodology was applied to core samples of opalinus clay within the framework of an international investigation being carried out at Mt. Terri, Canton Jura, Switzerland. The calculated porewater compositions are described and discussed in relation to experimental data from the analyses of borehole seepage water and water samples obtained from squeezing tests. Because the latter two waters were clearly out of the equilibrium, only a comparison based on general aqueous features was attempted. In all three cases the groundwaters were high ionic strength Na-Cl types. The experimentally determined pH values were in the range 7.5-8 whereas for the modelled porewater a value near 6 was calculated. This discrepancy was explained by postulating that the sampled waters lost dissolved CO{sub 2} through out-gassing. (author) 5 figs., 11 tabs., refs.

  4. Carbon sequestration via reaction with basaltic rocks: geochemical modeling and experimental results

    Science.gov (United States)

    Rosenbauer, Robert J.; Thomas, Burt; Bischoff, James L.; Palandri, James

    2012-01-01

    Basaltic rocks are potential repositories for sequestering carbon dioxide (CO2) because of their capacity for trapping CO2 in carbonate minerals. We carried out a series of thermodynamic equilibrium models and high pressure experiments, reacting basalt with CO2-charged fluids over a range of conditions from 50 to 200 °C at 300 bar. Results indicate basalt has a high reactivity to CO2 acidified brine. Carbon dioxide is taken up from solution at all temperatures from 50 to 200 °C, 300 bar, but the maximum extent and rate of reaction occurs at 100 °C, 300 bar. Reaction path simulations utilizing the geochemical modeling program CHILLER predicted an equilibrium carbonate alteration assemblage of calcite, magnesite, and siderite, but the only secondary carbonate identified in the experiments was a ferroan magnesite. The amount of uptake at 100 °C, 300 bar ranged from 8% by weight for a typical tholeite to 26% for a picrite. The actual amount of CO2 uptake and extent of rock alteration coincides directly with the magnesium content of the rock suggesting that overall reaction extent is controlled by bulk basalt Mg content. In terms of sequestering CO2, an average basaltic MgO content of 8% is equivalent to 2.6 × 108 metric ton CO2/km3 basalt.

  5. Net Acid Production, Acid Neutralizing Capacity, and Associated Mineralogical and Geochemical Characteristics of Animas River Watershed Igneous Rocks Near Silverton, Colorado

    Science.gov (United States)

    Yager, Douglas B.; Choate, LaDonna; Stanton, Mark R.

    2008-01-01

    This report presents results from laboratory and field studies involving the net acid production (NAP), acid neutralizing capacity (ANC), and magnetic mineralogy of 27 samples collected in altered volcanic terrain in the upper Animas River watershed near Silverton, Colo., during the summer of 2005. Sampling focused mainly on the volumetrically important, Tertiary-age volcanic and plutonic rocks that host base- and precious-metal mineralization in the study area. These rocks were analyzed to determine their potential for neutralization of acid-rock drainage. Rocks in the study area have been subjected to a regional propylitic alteration event, which introduced calcite, chlorite (clinochlore), and epidote that have varying amounts and rates of acid neutralizing capacity (ANC). Locally, hydrothermal alteration has consumed any ANC and introduced minerals, mainly pyrite, that have a high net acid production (NAP). Laboratory studies included hydrogen pyroxide (H2O2) acid digestion and subsequent sodium hydroxide (NaOH) titration to determine NAP, and sulfuric acid (H2SO4) acid titration experiments to determine ANC. In addition to these environmental rock-property determinations, mineralogical, chemical, and petrographic characteristics of each sample were determined through semiquantitative X-ray diffractometry (Rietveld method), optical mineralogy, wavelength dispersive X-ray fluorescence, total carbon-carbonate, and inductively coupled plasma?mass spectrometric analysis. An ANC ranking was assigned to rock samples based on calculated ANC quantity in kilograms/ton (kg/t) calcium carbonate equivalent and ratios of ANC to NAP. Results show that talus near the southeast Silverton caldera margin, composed of andesite clasts of the Burns Member of the Silverton Volcanics, has the highest ANC (>100 kg/t calcium carbonate equivalent) with little to no NAP. The other units found to have moderate to high ANC include (a) andesite lavas and volcaniclastic rocks of the San Juan

  6. Coupling R and PHREEQC: an interactive and extensible environment for efficient programming of geochemical models

    Science.gov (United States)

    De Lucia, Marco; Kühn, Michael

    2013-04-01

    manipulations and visualization in a powerful high level language, and benefiting from an enormous amount of third-party open source R extensions. The possibility to rapidly prototype complex algorithms involving geochemical modelling is in our opinion a huge advantage. A demonstration is given by the successful evaluation of a strategy to reduce the CPU-time needed to perform reactive transport simulations in a sequential coupling scheme. The idea is the "reduction" of the number of actual chemical simulations to perform at every time step, by searching for "duplicates" of each chemical simulations in the grid: such comparison involves typically a huge number of elements (one chemical simulation for grid element for time step) and a quite large number of variables (concentrations and mineral abundances). However, through the straightforward implementation of the prototype algorithm through the R/PHREEQC interface, we found out that the scan is extremely cost-effective in terms of CPU-time and typically allows a relevant speedup for simulations starting from a homogeneous or zone-homogeneous state. This speedup can even greatily exceed that of parallelization in some favorable but not unfrequent case. This feature should therefore be implemented in reactive transport simulators. References [1] Parkhurst D, Appelo C (1999) Users guide to PHREEQC (version 2). Tech. rep, U.S. Geological Survey. [2] Beyer C, Li D, De Lucia M, Kühn M, Bauer S (2012): Modelling CO2-induced fluid-rock interactions in the Altensalzwedel gas reservoir. Part II: coupled reactive transport simulation. Environ. Earth Sci., 67, 2, 573-588. [3] R Core Team (2012) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org/. [4] Kühn M, Münch U (2012) CLEAN: CO2 Large-Scale Enhanced Gas Recovery. GEOTECHNOLOGIEN Science Report No. 19. Series: Advanced. Technologies in Earth Sciences, 199 p, ISBN 978-3-642-31676-0.

  7. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122626 Li Dongfeng ( Liaoning Institute of Mineral Resources Exploration,Shenyang 110032,China ) Application of Comprehensive Geophysical-Geochemical Method in Toudao-yingzi Gold Field ( Journal of Liaoning Technical University ( Natural Sciences ), ISSN1008-0562,CN21-1379 / N,30 ( 6 ), 2011,p.849-852,1illus.,2tables,10refs. ) Key words:gold ores,geophysical exploration,geochemical exploration,Liaoning Province

  8. Modelling of Biometric Identification System with Given Parameters Using Colored Petri Nets

    Science.gov (United States)

    Petrosyan, G.; Ter-Vardanyan, L.; Gaboutchian, A.

    2017-05-01

    Biometric identification systems use given parameters and function on the basis of Colored Petri Nets as a modelling language developed for systems in which communication, synchronization and distributed resources play an important role. Colored Petri Nets combine the strengths of Classical Petri Nets with the power of a high-level programming language. Coloured Petri Nets have both, formal intuitive and graphical presentations. Graphical CPN model consists of a set of interacting modules which include a network of places, transitions and arcs. Mathematical representation has a well-defined syntax and semantics, as well as defines system behavioural properties. One of the best known features used in biometric is the human finger print pattern. During the last decade other human features have become of interest, such as iris-based or face recognition. The objective of this paper is to introduce the fundamental concepts of Petri Nets in relation to tooth shape analysis. Biometric identification systems functioning has two phases: data enrollment phase and identification phase. During the data enrollment phase images of teeth are added to database. This record contains enrollment data as a noisy version of the biometrical data corresponding to the individual. During the identification phase an unknown individual is observed again and is compared to the enrollment data in the database and then system estimates the individual. The purpose of modeling biometric identification system by means of Petri Nets is to reveal the following aspects of the functioning model: the efficiency of the model, behavior of the model, mistakes and accidents in the model, feasibility of the model simplification or substitution of its separate components for more effective components without interfering system functioning. The results of biometric identification system modeling and evaluating are presented and discussed.

  9. Using Petri Nets For Resource Management Modeling In The Operating Systems

    Directory of Open Access Journals (Sweden)

    Adalat Karimov

    2012-01-01

    Full Text Available Nowadays, with advances in computer science and increase in processor speed, modeling methods have found extensive applications in industrial fields. Petri Nets are one of these modeling methods. Petri Nets are based on graph theory and are applied specifically for concurrent and asynchronous applications. As executable models, they are capable of graphical description of complicated systems. On the other hand, development of hardware and other peripheral computer resources and development of various computer software systems call for efficient and powerful operating systems, so that users can use the software and hardware items in an effective manner. The purpose of this article is to study the application of Petri Nets for modeling resource management in operating systems with the aim of optimal utilization of resources and Deadlock Avoidance in the Operating Systems.

  10. Formal and Executable Specification of Random Waypoint Mobility Model Using Timed Coloured Petri Nets for WMN

    Directory of Open Access Journals (Sweden)

    Naeem Akhtar Khan

    2014-01-01

    Full Text Available The wireless mesh network (WMN is an emerging and cost-effective alternative paradigm for the next generation wireless networks in many diverse applications. In the performance evaluation of routing protocol for the WMN, it is essential that it should be evaluated under realistic conditions. The usefulness of specific mobility protocol can be determined by selection of mobility model. This paper introduces a coloured Petri nets (CP-nets based formal model for implementation, simulation, and analysis of most widely used random waypoint (RWP mobility model for WMNs. The formal semantics of hierarchical timed CP-nets allow us to investigate the terminating behavior of the transitions using state space analysis techniques. The proposed implementation improves the RWP mobility model by removing the “border effect” and resolves the “speed decay” problem.

  11. Generic Procedure for Coupling the PHREEQC Geochemical Modeling Framework with Flow and Solute Transport Simulators

    Science.gov (United States)

    Wissmeier, L. C.; Barry, D. A.

    2009-12-01

    Computer simulations of water availability and quality play an important role in state-of-the-art water resources management. However, many of the most utilized software programs focus either on physical flow and transport phenomena (e.g., MODFLOW, MT3DMS, FEFLOW, HYDRUS) or on geochemical reactions (e.g., MINTEQ, PHREEQC, CHESS, ORCHESTRA). In recent years, several couplings between both genres of programs evolved in order to consider interactions between flow and biogeochemical reactivity (e.g., HP1, PHWAT). Software coupling procedures can be categorized as ‘close couplings’, where programs pass information via the memory stack at runtime, and ‘remote couplings’, where the information is exchanged at each time step via input/output files. The former generally involves modifications of software codes and therefore expert programming skills are required. We present a generic recipe for remotely coupling the PHREEQC geochemical modeling framework and flow and solute transport (FST) simulators. The iterative scheme relies on operator splitting with continuous re-initialization of PHREEQC and the FST of choice at each time step. Since PHREEQC calculates the geochemistry of aqueous solutions in contact with soil minerals, the procedure is primarily designed for couplings to FST’s for liquid phase flow in natural environments. It requires the accessibility of initial conditions and numerical parameters such as time and space discretization in the input text file for the FST and control of the FST via commands to the operating system (batch on Windows; bash/shell on Unix/Linux). The coupling procedure is based on PHREEQC’s capability to save the state of a simulation with all solid, liquid and gaseous species as a PHREEQC input file by making use of the dump file option in the TRANSPORT keyword. The output from one reaction calculation step is therefore reused as input for the following reaction step where changes in element amounts due to advection

  12. Hierarchical Colored Timed Petri Nets for Maintenance Process Modeling of Civil Aircraft

    Institute of Scientific and Technical Information of China (English)

    FU Cheng-cheng; SUN You-chao; LU Zhong

    2008-01-01

    Civil aircraft maintenance process simulation model is an effective method for analyzing the maintainability of a civil aircraft. First, we present the Hierarchical Colored Timed Petri Nets for maintenance process modeling of civil aircraft. Then, we expound a general method of civil aircraft maintenance activities, determine the maintenance level for decomposition, and propose the methods of describing logic of relations between the maintenance activities based on Petri Net. Finally, a time Colored Petri multi-level network modeling and simulation procedures and steps are given with the maintenance example of the landing gear burst tire of a certain type of aircraft. The feasibility of the method is proved by the example.

  13. METHOD OF DISPLAYING AN EXECUTABLE BUSINESS PROCESS MODELS INTO PETRI NETS

    Directory of Open Access Journals (Sweden)

    Igor G. Fedorov

    2013-01-01

    Full Text Available Executable business process models, as well as programs, require evidence of a defect-free finish. The methods based on the formalism of Petri nets are widely used. A business process is a network of dishes, and its properties are set by the analysis of the properties of the network. The aim is to study the methods of displaying an executable business process model in a Petri net. Analysis of the properties of the resulting model allows us to prove a number of important properties: it is a network of free choice and clean without looping.

  14. Hydro-geochemical modeling of subalpine urbanized area: geochemical characterization of the shallow and deep aquifers of the urban district of Como (first results).

    Science.gov (United States)

    Terrana, Silvia; Brunamonte, Fabio; Frascoli, Francesca; Ferrario, Maria Francesca; Michetti, Alessandro Maria; Pozzi, Andrea; Gambillara, Roberto; Binda, Gilberto

    2016-04-01

    One of the greatest environmental and social-economics threats is climate change. This topic, in the next few years, will have a significant impact on the availability of water resources of many regions. This is compounded by the strong anthropization of water systems that shows an intensification of conflicts for water resource exploitation. Therefore, it is necessary a sustainable manage of natural resources thorough knowledge of the hosting territories. The development of investigation and data processing methods are essential to reduce costs for the suitable use and protection of resources. Identify a sample area for testing the best approach is crucial. This research aims to find a valid methodology for the characterization, modeling and management of subalpine urban aquifers, and the urban district of Como appears perfect. The city of Como is located at the southern end of the western sector of Lake Como (N Italy). It is a coastal town, placed on a small alluvial plain, therefore in close communication with the lake. The plain is drained by two streams, which are presently artificially buried, and have an underground flow path in the urban section till the mouth. This city area, so, is suitable for this project as it is intensely urbanized, its dimensions is not too extensive and it is characterized by two aquifers very important and little known. These are a shallow aquifer and a deep aquifer, which are important not only for any water supply, but also for the stability of the ground subsidence in the city. This research is also the opportunity to work in a particular well-known area with high scientific significance; however, there is complete absence of information regarding the deep aquifer. Great importance has also the chosen and used of the more powerful open source software for this type of area, such as PHREEQC, EnvironInsite, PHREEQE etc., used for geological and geochemical data processing. The main goal of this preliminary work is the

  15. Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.

    Science.gov (United States)

    Wang, Lei; Chen, Qi; Jamro, Imtiaz Ali; Li, Rundong; Li, Yanlong; Li, Shaobai; Luan, Jingde

    2016-06-01

    Municipal solid waste incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions.

  16. [Influence of ammonia on leaching behaviors of incineration fly ash and its geochemical modeling].

    Science.gov (United States)

    Guan, Zhen-Zhen; Chen, De-Zhen; Thomas, Astrup

    2013-06-01

    Incineration fly ash could be contaminated with NH3 that was slipped from the ammonia-based selective non-catalytic reduction(SNCR) process and from evaporation of municipal solid wastes' leachate involved in the wastes. This research was conducted to investigate the impacts of ammonia on leaching of dissolved organic carbon (DOC) and metals from incineration fly ash in the pH range of 3.66-12.44 with an active ammonia spike. A geochemical modeling software Visual MINTEQ was adopted to calculate the chemical speciation of metals under the leaching conditions to reveal the mechanism behind the impacts. It was proved that at pH > 9, the leaching of DOC increased significantly in the presence of high concentrations of ammonia (> or = 1 357 mg x L(-1)), but there was little effect when the ammonia level in eluates was not higher than 537 mg x L(-1). At pH or = 3 253 mg x L(-1)) mobilized Cd, Cu, Ni and Zn significantly due to the formation of soluble metal-ammonia complexes, and the leaching rates reached their peaks at pH around 9; however, ammonia had little impacts on Al and Pb leaching within this pH range. At pH > 12, for Cd, Cu, Ni and Zn, their leaching species were predominantly in the form of hydroxide complexes. Under the ammonia concentration of 3253 mg x L(-1), the Visual MINTEQ modeling results were compared with the experimental data, and it was proved that the leaching of Al, Pb and Zn was mainly controlled by precipitation/dissolution modeling, while Cd, Cu and Ni were controlled by precipitation/dissolution and surface complexation/precipitation processes; Visual MINTEQ modeling could well describe the leaching behaviors of Al, Cu, Pb and Zn from incineration fly ash.

  17. Geochemical modeling of leaching from MSVI air-pollution-control residues

    DEFF Research Database (Denmark)

    Astrup, Thomas; Dijkstra, J.J.; Comans, R.N.J.

    2006-01-01

    This paper provides an improved understanding of the leaching behavior of waste incineration air-pollution-control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts from...... residues. Leaching experiments were performed at a range of pH-values using carbonated and noncarbonated versions of two APC residues. The leaching data were evaluated by geochemical speciation modeling and discussed with respect to possible solubility control. The leaching of major elements as well...... of Al, Ba, Ca, Cr, Pb, S, Si, V, and Zn was found influenced by solubility control from Al2O3, Al(OH)3, Ba(S,Cr)O4 solid solutions, BaSO4, Ca6Al2(SO4)3(OH)12â26H2O, CaAl2Si4O12â2H2O, Ca-(OH)2, CaSiO3, CaSO4â2H2O, CaZn2(OH)6â2H2O, KAlSi2O6, PbCO3, PbCrO4, Pb2O3, Pb2V2O7, Pb3(VO4)2, ZnO, Zn2SiO4, and Zn...

  18. Modeling function calls in program control flow in terms of Petri Nets

    Directory of Open Access Journals (Sweden)

    Dmitriy Kharitonov

    Full Text Available This article presents a method for representing the C/C++ function call in terms of compositional Petri Nets. Principles of modeling function and function call in the program are described. Formal composition operations to construct program model from mod ...

  19. A hybrid architecture for the implementation of the Athena neural net model

    Science.gov (United States)

    Koutsougeras, C.; Papachristou, C.

    1989-01-01

    The implementation of an earlier introduced neural net model for pattern classification is considered. Data flow principles are employed in the development of a machine that efficiently implements the model and can be useful for real time classification tasks. Further enhancement with optical computing structures is also considered.

  20. Geophysical modeling and geochemical analysis for hydrogeologic assessment of the Steamboat Hills area, Nevada

    Science.gov (United States)

    Skalbeck, John David

    2001-07-01

    Three studies constitute the hydrogeologic assessment of the Steamboat Hills area, Washoe County, Nevada. Geophysical modeling and geochemical analysis are used to assess the hydrogeologic connection between a fractured bedrock geothermal system used to produce electrical power and surrounding alluvial aquifer basins used for municipal drinking water supply. Understanding the hydrogeologic connection between these two water resources is important for long-term management of these resources. Coupled 2.75-D forward modeling of multiple gravity and aeromagnetic profiles constrained by geological and physical properties (density, magnetic susceptibility, remanent magnetic) data yields a detailed 3-D geologic model of the geothermal system and the alluvial basins. A new method is presented for modeling the geothermal reservoir based on altered physical properties of host rock that yields a reservoir volume estimate that is double the previously assumed volume. The configuration of the modeled geothermal reservoir suggests that a previously unrecognized thermal water up-flow zone may exist along the west flank of the Steamboat Hills. Model results delineate the elevation and thickness of geologic units that can be used in numerical modeling of groundwater flow, planning exploration drilling, and evaluating fully 3-D forward modeling software. The Steamboat Hills geothermal resource area offers an excellent opportunity to test an exploration strategy using magnetics. A zone of demagnetized rock within the geothermal resource area resulting from thermochemical alteration due to thermal water flow along faults and fractures is apparent as an aeromagnetic low anomaly. Anomalously low ground magnetic data delineate a fault that conducts thermal water from the geothermal system to an alluvial aquifer. Vertical magnetic susceptibility from core measurements yields an average value for altered granodiorite used in forward modeling. Permeable fractures and a major fault zone

  1. Improved Geothermometry Through Multivariate Reaction-path Modeling and Evaluation of Geomicrobiological Influences on Geochemical Temperature Indicators: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mattson, Earl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fujita, Yoshiko [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Carl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Reed, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Vicki [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    The project was aimed at demonstrating that the geothermometric predictions can be improved through the application of multi-element reaction path modeling that accounts for lithologic and tectonic settings, while also accounting for biological influences on geochemical temperature indicators. The limited utilization of chemical signatures by individual traditional geothermometer in the development of reservoir temperature estimates may have been constraining their reliability for evaluation of potential geothermal resources. This project, however, was intended to build a geothermometry tool which can integrate multi-component reaction path modeling with process-optimization capability that can be applied to dilute, low-temperature water samples to consistently predict reservoir temperature within ±30 °C. The project was also intended to evaluate the extent to which microbiological processes can modulate the geochemical signals in some thermal waters and influence the geothermometric predictions.

  2. Geochemical simulation of the formation of brine and salt minerals based on Pitzer model in Caka Salt Lake

    Institute of Scientific and Technical Information of China (English)

    LIU; Xingqi; CAI; Keqin; YU; Shengsong

    2004-01-01

    The geochemical simulation of the formation of brine and salt minerals based on Pitzer model was made in Caka Salt Lake. The evolution of the mixed surface-water and the mineral sequences were calculated and compared with the hydrochemical compositions of the brine and the salt minerals of the deposit in Caka Salt Lake. The results show that the formation temperature of the lake is between 0℃ and 5℃, which is well identical with other studies. The mixing of salt-karst water with the surface waters, neglected by the former researchers, is very important to the formation of the lake, indicating that the initial waters resulting in the formation of the lake are multi-source. It is the first time to use Pitzer model in China for making geochemical simulation of the formation and evolution of inland salt lake and satisfactory results have been achieved.

  3. Modelling Local and Global Behaviour: Petri Nets and Event Coordination

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    2011-01-01

    Today, it is possible to generate major parts of a software system from models. Most of the generated code, however, concerns the structural parts of the software; the parts that concern the functionality or behaviour of a system are still programmed manually. In order to overcome this problem, we...... are developing the concept of coordination diagrams that define the global behaviour on top of structural software models. Basically, these diagrams define how the local behaviour of an element is coordinated with the behaviour of the elements it is connected to. The exact concepts of these coordination diagrams...... and their notation is still under development, but there exists a first prototype for experimenting and for fine-tuning its features. We call it the Event Coordination Notation (ECNO). For experimenting with the ECNO, we implemented also a simple modelling notation for the local behaviour, which is based on Petri...

  4. The ADAPT Tool: From AADL Architectural Models to Stochastic Petri Nets through Model Transformation

    CERN Document Server

    Rugina, Ana E; Kaaniche, Mohamed

    2008-01-01

    ADAPT is a tool that aims at easing the task of evaluating dependability measures in the context of modern model driven engineering processes based on AADL (Architecture Analysis and Design Language). Hence, its input is an AADL architectural model annotated with dependability-related information. Its output is a dependability evaluation model in the form of a Generalized Stochastic Petri Net (GSPN). The latter can be processed by existing dependability evaluation tools, to compute quantitative measures such as reliability, availability, etc.. ADAPT interfaces OSATE (the Open Source AADL Tool Environment) on the AADL side and SURF-2, on the dependability evaluation side. In addition, ADAPT provides the GSPN in XML/XMI format, which represents a gateway to other dependability evaluation tools, as the processing techniques for XML files allow it to be easily converted to a tool-specific GSPN.

  5. NetLand: quantitative modeling and visualization of Waddington's epigenetic landscape using probabilistic potential.

    Science.gov (United States)

    Guo, Jing; Lin, Feng; Zhang, Xiaomeng; Tanavde, Vivek; Zheng, Jie

    2017-05-15

    Waddington's epigenetic landscape is a powerful metaphor for cellular dynamics driven by gene regulatory networks (GRNs). Its quantitative modeling and visualization, however, remains a challenge, especially when there are more than two genes in the network. A software tool for Waddington's landscape has not been available in the literature. We present NetLand, an open-source software tool for modeling and simulating the kinetic dynamics of GRNs, and visualizing the corresponding Waddington's epigenetic landscape in three dimensions without restriction on the number of genes in a GRN. With an interactive and graphical user interface, NetLand can facilitate the knowledge discovery and experimental design in the study of cell fate regulation (e.g. stem cell differentiation and reprogramming). NetLand can run under operating systems including Windows, Linux and OS X. The executive files and source code of NetLand as well as a user manual, example models etc. can be downloaded from http://netland-ntu.github.io/NetLand/ . zhengjie@ntu.edu.sg. Supplementary data are available at Bioinformatics online.

  6. STOCHASTIC OBJECT-ORIENTED PETRI NETS (SOPNS) AND ITS APPLICATION IN MODELING OF MANUFACTURING SYSTEM RELIABILITY

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhibin; He Junming

    2003-01-01

    Object-oriented Petri nets (OPNs) is extended into stochastic object-oriented Petri nets (SOPNs) by associating the OPN of an object with stochastic transitions and introducing stochastic places. The stochastic transition of the SOPNs of a production resources can be used to model its reliability, while the SOPN of a production resource can describe its performance with reliability considered. The SOPN model of a case production system is built to illustrate the relationship between the system's performances and the failures of individual production resources.

  7. A Model for the Calculation of Velocity Reduction Behind A Plane Fishing Net

    Institute of Scientific and Technical Information of China (English)

    GUI Fu-kun; LI Yu-cheng; ZHAO Yun-peng; DONG Guo-hai

    2006-01-01

    A model for the calculation of velocity reduction behind a fishing net is proposed in this paper. Comparisons are made between the calculated results and experimental data. It is shown that by the application of the effective adjacent area coefficient of fluid flowing around a solid structure to the fishing net, the calculated results agree well with the experimental data. The model proposed in this paper can also be applied to the analysis of the velocity reduction within a fishing cage and can be introduced into the numerical simulation of the hydrodynamic behavior of fishing cages for the improvement of computational accuracy.

  8. Geochemical modelling for predicting the long-term performance of zeolite-PRB to treat lead contaminated groundwater

    Science.gov (United States)

    Obiri-Nyarko, Franklin; Kwiatkowska-Malina, Jolanta; Malina, Grzegorz; Kasela, Tomasz

    2015-06-01

    The feasibility of using geochemical modelling to predict the performance of a zeolite-permeable reactive barrier (PRB) for treating lead (Pb2 +) contaminated water was investigated in this study. A short-term laboratory column experiment was first performed with the zeolite (clinoptilolite) until the elution of 50 PV (1 PV = ca. 283 mL). Geochemical simulations of the one-dimensional transport of the Pb2+, considering removal processes including: ion-exchange, adsorption and complexation; the concomitant release of exchangeable cations (Ca2 +, Mg2 +, Na+, and K+) and the changes in pH were subsequently performed using the geochemical model PHREEQC. The results showed a reasonable agreement between the experimental results and the numerical simulations, with the exception of Ca2 + for which a great discrepancy was observed. The model also indicated the formation of secondary mineral precipitates such as goethite and hematite throughout the experiment, of which the effect on the hydraulic conductivity was found to be negligible. The results were further used to extrapolate the long-term performance of the zeolite. We found the capacity would be completely exhausted at PV = 250 (ca. 3 days). The study, thus, generally demonstrates the applicability of PHREEQC to predict the short and long-term performance of zeolite-PRBs. Therefore, it can be used to assist in the design and for management purposes of such barriers.

  9. Geochemical modelling for predicting the long-term performance of zeolite-PRB to treat lead contaminated groundwater.

    Science.gov (United States)

    Obiri-Nyarko, Franklin; Kwiatkowska-Malina, Jolanta; Malina, Grzegorz; Kasela, Tomasz

    2015-01-01

    The feasibility of using geochemical modelling to predict the performance of a zeolite-permeable reactive barrier (PRB) for treating lead (Pb(2+)) contaminated water was investigated in this study. A short-term laboratory column experiment was first performed with the zeolite (clinoptilolite) until the elution of 50 PV (1 PV=ca. 283 mL). Geochemical simulations of the one-dimensional transport of the Pb(2+), considering removal processes including: ion-exchange, adsorption and complexation; the concomitant release of exchangeable cations (Ca(2+), Mg(2+), Na(+), and K(+)) and the changes in pH were subsequently performed using the geochemical model PHREEQC. The results showed a reasonable agreement between the experimental results and the numerical simulations, with the exception of Ca(2+) for which a great discrepancy was observed. The model also indicated the formation of secondary mineral precipitates such as goethite and hematite throughout the experiment, of which the effect on the hydraulic conductivity was found to be negligible. The results were further used to extrapolate the long-term performance of the zeolite. We found the capacity would be completely exhausted at PV=250 (ca. 3 days). The study, thus, generally demonstrates the applicability of PHREEQC to predict the short and long-term performance of zeolite-PRBs. Therefore, it can be used to assist in the design and for management purposes of such barriers.

  10. Geochemical monitoring of volcanic lakes. A generalized box model for active crater lakes

    Directory of Open Access Journals (Sweden)

    Franco Tassi

    2011-06-01

    Full Text Available

    In the past, variations in the chemical contents (SO42−, Cl−, cations of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes, taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area, lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf- kg/s –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.

  11. Geochemical Modeling of Leaching from MSWI Air-Pollution-Control Residues

    Energy Technology Data Exchange (ETDEWEB)

    Astrup, T.; Christensen, T.H. [Institute of Environment and Resources, Technical University of Denmark, Building 115, DK-2800 Lyngby (Denmark); Dijkstra, J.J.; Van der Sloot, H.A. [Energy Research Centre of The Netherlands (ECN), PO Box 1, 1755 ZG Petten (Netherlands); Comans, R.N.J. [Wageningen University, Department of Soil Quality, P.O. Box 8005, 6700 EC Wageningen (Netherlands)

    2006-04-15

    This paper provides an improved understanding of the leaching behavior of waste incineration air-pollution-control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts from residues. Leaching experiments were performed at a range of pH-values using carbonated and noncarbonated versions of two APC residues. The leaching data were evaluated by geochemical speciation modeling and discussed with respect to possible solubility control. The leaching of major elements as well as trace elements was generally found to be strongly dependent on pH. As leaching characterization was performed in the absence of high salt levels, the presented results represent long-term leaching after initial washout from a disposal site, that is, liquid-to solid ratios above 1-2 L/kg. The leaching of Al, Ba, Ca, Cr, Pb, S, Si, V, and Zn was found influenced by solubility control from Al2O3, Al(OH)3, Ba(S,Cr)O4 solid solutions, BaSO4, Ca6Al2(SO4)3(OH)12.26H2O, CaAl2Si4O12.2H2O, Ca(OH)2, CaSiO3, CaSO4.2H2O, CaZn2(OH)6.2H2O, KAlSi2O6, PbCO3, PbCrO4, Pb2O3, Pb2V2O7, Pb3(VO4)2, ZnO, Zn2SiO4, and ZnSiO3. The presented dataset and modeling results form a thorough contribution to the assessment of long-term leaching behavior of APC residues under a wide range of conditions.

  12. BiomeNet: a Bayesian model for inference of metabolic divergence among microbial communities.

    Directory of Open Access Journals (Sweden)

    Mahdi Shafiei

    2014-11-01

    Full Text Available Metagenomics yields enormous numbers of microbial sequences that can be assigned a metabolic function. Using such data to infer community-level metabolic divergence is hindered by the lack of a suitable statistical framework. Here, we describe a novel hierarchical Bayesian model, called BiomeNet (Bayesian inference of metabolic networks, for inferring differential prevalence of metabolic subnetworks among microbial communities. To infer the structure of community-level metabolic interactions, BiomeNet applies a mixed-membership modelling framework to enzyme abundance information. The basic idea is that the mixture components of the model (metabolic reactions, subnetworks, and networks are shared across all groups (microbiome samples, but the mixture proportions vary from group to group. Through this framework, the model can capture nested structures within the data. BiomeNet is unique in modeling each metagenome sample as a mixture of complex metabolic systems (metabosystems. The metabosystems are composed of mixtures of tightly connected metabolic subnetworks. BiomeNet differs from other unsupervised methods by allowing researchers to discriminate groups of samples through the metabolic patterns it discovers in the data, and by providing a framework for interpreting them. We describe a collapsed Gibbs sampler for inference of the mixture weights under BiomeNet, and we use simulation to validate the inference algorithm. Application of BiomeNet to human gut metagenomes revealed a metabosystem with greater prevalence among inflammatory bowel disease (IBD patients. Based on the discriminatory subnetworks for this metabosystem, we inferred that the community is likely to be closely associated with the human gut epithelium, resistant to dietary interventions, and interfere with human uptake of an antioxidant connected to IBD. Because this metabosystem has a greater capacity to exploit host-associated glycans, we speculate that IBD

  13. Modeling injection molding of net-shape active ceramic components.

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Tomas (Gram Inc.); Cote, Raymond O.; Grillet, Anne Mary; Yang, Pin; Hopkins, Matthew Morgan; Noble, David R.; Notz, Patrick K.; Rao, Rekha Ranjana; Halbleib, Laura L.; Castaneda, Jaime N.; Burns, George Robert; Mondy, Lisa Ann; Brooks, Carlton, F.

    2006-11-01

    To reduce costs and hazardous wastes associated with the production of lead-based active ceramic components, an injection molding process is being investigated to replace the current machining process. Here, lead zirconate titanate (PZT) ceramic particles are suspended in a thermoplastic resin and are injected into a mold and allowed to cool. The part is then bisque fired and sintered to complete the densification process. To help design this new process we use a finite element model to describe the injection molding of the ceramic paste. Flow solutions are obtained using a coupled, finite-element based, Newton-Raphson numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. Thermal, rheological, and wetting properties of the PZT paste are measured for use as input to the model. The viscosity of the PZT is highly dependent both on temperature and shear rate. One challenge in modeling the injection process is coming up with appropriate constitutive equations that capture relevant phenomenology without being too computationally complex. For this reason we model the material as a Carreau fluid and a WLF temperature dependence. Two-dimensional (2D) modeling is performed to explore the effects of the shear in isothermal conditions. Results indicate that very low viscosity regions exist near walls and that these results look similar in terms of meniscus shape and fill times to a simple Newtonian constitutive equation at the shear-thinned viscosity for the paste. These results allow us to pick a representative viscosity to use in fully three-dimensional (3D) simulation, which because of numerical complexities are restricted to using a Newtonian constitutive equation. Further 2D modeling at nonisothermal conditions shows that the choice of

  14. Assessment of the expected construction company’s net profit using neural network and multiple regression models

    Directory of Open Access Journals (Sweden)

    H.H. Mohamad

    2013-09-01

    This research aims to develop a mathematical model for assessing the expected net profit of any construction company. To achieve the research objective, four steps were performed. First, the main factors affecting firms’ net profit were identified. Second, pertinent data regarding the net profit factors were collected. Third, two different net profit models were developed using the Multiple Regression (MR and the Neural Network (NN techniques. The validity of the proposed models was also investigated. Finally, the results of both MR and NN models were compared to investigate the predictive capabilities of the two models.

  15. A reformulation of the Cost Plus Net Value Change (C+NVC) model of wildfire economics

    Science.gov (United States)

    Geoffrey H. Donovan; Douglas B. Rideout

    2003-01-01

    The Cost plus Net Value Change (C+NVC) model provides the theoretical foundation for wildland fire economics and provides the basis for the National Fire Management Analysis System (NFMAS). The C+NVC model is based on the earlier least Cost plus Loss model (LC+L) expressed by Sparhawk (1925). Mathematical and graphical analysis of the LC+L model illustrates two errors...

  16. Bioenergetic modeling reveals that Chinese green tree vipers select postprandial temperatures in laboratory thermal gradients that maximize net energy intake.

    Science.gov (United States)

    Tsai, Tein-Shun; Lee, How-Jing; Tu, Ming-Chung

    2009-11-01

    With bioenergetic modeling, we tested the hypothesis that reptiles maximize net energy gain by postprandial thermal selection. Previous studies have shown that Chinese green tree vipers (Trimeresurus s. stejnegeri) have postprandial thermophily (mean preferred temperature T(p) for males =27.8 degrees C) in a linear thigmothermal gradient when seclusion sites and water existed. With some published empirical models of digestion associated factors for this snake, we calculated the average rate (E(net)) and efficiency (K(net)) of net energy gain from possible combinations of meal size, activity level, and feeding frequency at each temperature. The simulations consistently revealed that E(net) maximizes at the T(p) of these snakes. Although the K(net) peaks at a lower temperature than E(net), the value of K(net) remains high (>=0.85 in ratio to maximum) at the peak temperature of E(net). This suggested that the demands of both E(net) and K(net) can be attained by postprandial thermal selection in this snake. In conclusion, the data support our prediction that postprandial thermal selection may maximize net energy gain.

  17. Modelling Local and Global Behaviour: Petri Nets and Event Coordination

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    2012-01-01

    to address this problem, we developed the notation of coordination diagrams, which allows us to define the global behaviour of a software system on top of existing class diagrams. One of the major objectives of coordination diagrams was to make it easy to integrate them and the code generated from them...... call it the Event Coordination Notation (ECNO). ECNO’s coordination diagrams define the global behaviour of a system only: they define how the local behaviour is coordinated and jointly executed in so-called interactions. In principle, ECNO is independent from a specific notation for modelling...

  18. Geochemical modelling of groundwater evolution and residence time at the Olkiluoto site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy (Finland); Leino-Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    1999-05-01

    An understanding of the geochemical evolution of groundwater is an essential part of the performance assessment and safety analysis of the final disposal of radioactive waste into the bedrock. The performance of technical barriers and migration of possibly released radionuclides depend on chemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions which control chemical conditions in groundwater. The objective of this study is to interpret the processes and factors which control the hydrogeochemistry, such as pH and redox conditions. A model of the hydrogeochemical progress in different parts of the crystalline bedrock at Olkiluoto has been created and the significance of chemical reactions and groundwater mixing along different flowpaths calculated. Long term hydrodynamics have also been evaluated. The interpretation and modelling are based on water samples (63 altogether) obtained from precipitation, Baltic Sea, soil layer, shallow wells in the bedrock, and eight deep boreholes in the bedrock for which a comprehensive data set on dissolved chemical species and isotopes was available. Some analyses of dissolved gases and fracture calcite and their isotopic measurements were also utilised. The data covers the bedrock at Olkiluoto to a depth of 1000 m. The results from groundwater chemistry, isotopes, petrography, hydrogeology of the site, geomicrobial studies, and PCA and speciation calculations were used in the evaluation of evolutionary processes at the site. The geochemical interpretation of water-rock interaction, isotope-chemical evolution and mixing of palaeo water types were approached by mass-balance calculations (NETPATH). Reaction-path calculations (EQ3/6) were used to verify the thermodynamic feasibility of the reaction models obtained. The interpretation and calculation of hydrochemical data from Olkiluoto reveals the complex nature of hydrogeochemical evolution at the site. Changes in

  19. ScaleNet: a literature-based model of scale insect biology and systematics.

    Science.gov (United States)

    García Morales, Mayrolin; Denno, Barbara D; Miller, Douglass R; Miller, Gary L; Ben-Dov, Yair; Hardy, Nate B

    2016-01-01

    Scale insects (Hemiptera: Coccoidea) are small herbivorous insects found on all continents except Antarctica. They are extremely invasive, and many species are serious agricultural pests. They are also emerging models for studies of the evolution of genetic systems, endosymbiosis and plant-insect interactions. ScaleNet was launched in 1995 to provide insect identifiers, pest managers, insect systematists, evolutionary biologists and ecologists efficient access to information about scale insect biological diversity. It provides comprehensive information on scale insects taken directly from the primary literature. Currently, it draws from 23,477 articles and describes the systematics and biology of 8194 valid species. For 20 years, ScaleNet ran on the same software platform. That platform is no longer viable. Here, we present a new, open-source implementation of ScaleNet. We have normalized the data model, begun the process of correcting invalid data, upgraded the user interface, and added online administrative tools. These improvements make ScaleNet easier to use and maintain and make the ScaleNet data more accurate and extendable. Database URL: http://scalenet.info.

  20. MAGic: A comprehensive model for earth system geochemical cycling over Phanerozoic time

    Science.gov (United States)

    MacKenzie, F. T.; Arvidson, R. S.; Guidry, M.

    2003-04-01

    Thirty years ago, Garrels and Mackenzie published a model describing the steady state behavior of the elements involved in the formation and destruction of sedimentary rocks: Al, C, Ca, Cl, Fe, K, Mg, Na, S, Si, and Ti (Garrels and Mackenzie 1972). We offer an update of that original work in a model that incorporates the basic reactions controlling atmospheric carbon dioxide and oxygen concentrations: continental and seafloor weathering of silicate and carbonate rocks, net ecosystem productivity, seawater-basalt exchange reactions, precipitation and diagenesis of chemical sediments (including production of authigenic silicates by ``reverse weathering''), oxidation-reduction reactions involving carbon, sulfur, and iron, and subduction-decarbonation reactions. Although this model contains feedback and forcing functions similar to those used in the GEOCARB models (Berner, 1991, 1994; Berner and Kothavala 2001), these functions are incorporated in a reservoir-reaction scheme that is considerably more detailed. Coupled reservoirs include shallow and deep cratonic silicate and carbonate rocks and sediments, seawater, atmosphere, oceanic sediments and basalts, and the shallow mantle. This model is consistent with constraints from recent work on the history of seawater and atmosphere composition from the evaporite, isotopic, floral, and mineralogical records. We have used this model to test the sensitivity to various uncertainties in the history of the earth-ocean-atmosphere system over the past 500 Ma: the advent of pelagic carbonate sedimentation, the stoichiometry of the seawater-basalt exchange reactions, the role of authigenic silicates, the importance of burial versus early diagenetic dolomite formation, and the relationship of these processes to rates of global tectonism. General results (consistent with proxies for seawater composition) include a net transfer of Mg from the carbonate (dolomite) to the silicate reservoir, elevated relative atmospheric CO_2

  1. GeoSys.Chem: Estimate of reservoir fluid characteristics as first step in geochemical modeling of geothermal systems

    Science.gov (United States)

    Verma, Mahendra P.

    2012-12-01

    A computer code GeoSys.Chem for the calculation of deep geothermal reservoir fluid characteristics from the measured physical-chemical parameters of separated water and condensed vapor samples obtained from drilled wells is presented. It was written as a dynamic link library (DLL) in Visual Basic in Visual Studio 2010 (VB.NET). Using this library a demonstration program GeoChem was developed in VB.NET, which accepts the input data file in the XML format. A stepwise calculation of deep reservoir fluid characteristics of 11 production wells of Los Azufres geothermal system is performed. The calculated concentration of CO2 (e.g.=1270 mmole/kg in the well AZ-09) in the vapor, discharged into the atmosphere at the weir box, from the water sample indicates some problem in the analysis of carbonic species concentrations. In the absence of good quality analysis of carbonic species it is suggested to consider the CO2 in the vapor sample at the separator and the total dissolved carbonic species concentration in the water sample (i.e., without considering the liberation of CO2 in the atmospheric vapor at the weir box) for the geothermal reservoir fluid composition calculations. Similarly, it presents various diagrams developed in Excel for the thermodynamic evolution of Los Azufres geothermal reservoir.

  2. RECONFIGURABLE PRODUCTION LINE MODELING AND SCHEDULING USING PETRI NETS AND GENETIC ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    XIE Nan; LI Aiping

    2006-01-01

    In response to the production capacity and functionality variations, a genetic algorithm (GA) embedded with deterministic timed Petri nets(DTPN) for reconfigurable production line(RPL) is proposed to solve its scheduling problem. The basic DTPN modules are presented to model the corresponding variable structures in RPL, and then the scheduling model of the whole RPL is constructed. And in the scheduling algorithm, firing sequences of the Petri nets model are used as chromosomes, thus the selection, crossover, and mutation operator do not deal with the elements in the problem space, but the elements of Petri nets model. Accordingly, all the algorithms for GA operations embedded with Petri nets model are proposed. Moreover, the new weighted single-objective optimization based on reconfiguration cost and E/T is used. The results of a DC motor RPL scheduling suggest that the presented DTPN-GA scheduling algorithm has a significant impact on RPL scheduling, and provide obvious improvements over the conventional scheduling method in practice that meets duedate, minimizes reconfiguration cost, and enhances cost effectivity.

  3. Health safety nets can break cycles of poverty and disease: a stochastic ecological model.

    Science.gov (United States)

    Plucinski, Mateusz M; Ngonghala, Calistus N; Bonds, Matthew H

    2011-12-07

    The persistence of extreme poverty is increasingly attributed to dynamic interactions between biophysical processes and economics, though there remains a dearth of integrated theoretical frameworks that can inform policy. Here, we present a stochastic model of disease-driven poverty traps. Whereas deterministic models can result in poverty traps that can only be broken by substantial external changes to the initial conditions, in the stochastic model there is always some probability that a population will leave or enter a poverty trap. We show that a 'safety net', defined as an externally enforced minimum level of health or economic conditions, can guarantee ultimate escape from a poverty trap, even if the safety net is set within the basin of attraction of the poverty trap, and even if the safety net is only in the form of a public health measure. Whereas the deterministic model implies that small improvements in initial conditions near the poverty-trap equilibrium are futile, the stochastic model suggests that the impact of changes in the location of the safety net on the rate of development may be strongest near the poverty-trap equilibrium.

  4. A modeling method of semiconductor fabrication flows with extended knowledge hybrid Petri nets

    Institute of Scientific and Technical Information of China (English)

    Zhou Binghai; Jiang Shuyu; Wang Shijin; Wu bin

    2008-01-01

    A modeling method of extended knowledge hybrid Petri nets (EKHPNs), incorporating object-oriented methods into hybrid Petri nets (HPNs), was presented and used for the representation and modeling of semiconductor wafer fabrication flows. To model the discrete and continuous parts of a complex semiconductor wafer fabrication flow, the HPNs were introduced into the EKHPNs. Object-oriented methods were combined into the EKHPNs for coping with the complexity of the fabrication flow. Knowledge annotations were introduced to solve input and output conflicts of the EKHPNs.Finally, to demonstrate the validity of the EKHPN method, a real semiconductor wafer fabrication case was used to illustrate the modeling procedure. The modeling results indicate that the proposed method can be used to model a complex semiconductor wafer fabrication flow expediently.

  5. Formalization and Verification of Business Process Modeling Based on UML and Petri Nets

    Institute of Scientific and Technical Information of China (English)

    YAN Zhi-jun; GAN Ren-chu

    2005-01-01

    In order to provide a quantitative analysis and verification method for activity diagrams based business process modeling, a formal definition of activity diagrams is introduced. And the basic requirements for activity diagrams based business process models are proposed. Furthermore, the standardized transformation technique between business process models and basic Petri nets is presented and the analysis method for the soundness and well-structured properties of business processes is introduced.

  6. Model-Based Testing of a Reactive System with Coloured Petri Nets

    DEFF Research Database (Denmark)

    Tjell, Simon

    2006-01-01

    In this paper, a reactive and nondeterministic system is tested. This is doneby applying a generic model that has been specified as a configurable Coloured PetriNet. In this way, model-based testing is possible for a wide class of reactive system atthe level of discrete events. Concurrently...... executed tasks are specified at a high levelof abstraction and test traces are collected through state space analysis of the model....

  7. Modeling and Control of Welding Flexible Manufacturing Cell Using Petri Net

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new welding flexible manufacturing cell (WFMC) with intelligent welding sensors was investigated. Based on the analysis of information flow in WFMC, automation Petri net control model has been studied, which can be extended to complex welding flexible manufacturing system in the future.

  8. Representing Resources in Petri Net Models: Hardwiring or Soft-coding?

    OpenAIRE

    2011-01-01

    This paper presents an interesting design problem in developing a new tool for discrete-event dynamic systems (DEDS). A new tool known as GPenSIM was developed for modeling and simulation of DEDS; GPenSIM is based on Petri Nets. The design issue this paper talks about is whether to represent resources in DEDS hardwired as a part of the Petri net structure (which is the widespread practice) or to soft code as common variables in the program code. This paper shows that soft coding resources giv...

  9. Assessing the Graphical and Algorithmic Structure of Hierarchical Coloured Petri Net Models

    Directory of Open Access Journals (Sweden)

    George Benwell

    1994-11-01

    Full Text Available Petri nets, as a modelling formalism, are utilised for the analysis of processes, whether for explicit understanding, database design or business process re-engineering. The formalism, however, can be represented on a virtual continuum from highly graphical to largely algorithmic. The use and understanding of the formalism will, in part, therefore depend on the resultant complexity and power of the representation and, on the graphical or algorithmic preference of the user. This paper develops a metric which will indicate the graphical or algorithmic tendency of hierarchical coloured Petri nets.

  10. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20151884 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing100083,China)Regional Geochemistry of Sanjiang Region in Yunnan Province and Its Copper-Polymetallic Prospecting Significance(Geophysical and Geochemical Exploration,ISSN1000-8918,

  11. Accounting for geochemical alterations of caprock fracture permeability in basin-scale models of leakage from geologic CO2 reservoirs

    Science.gov (United States)

    Guo, B.; Fitts, J. P.; Dobossy, M.; Bielicki, J. M.; Peters, C. A.

    2012-12-01

    Climate mitigation, public acceptance and energy, markets demand that the potential CO2 leakage rates from geologic storage reservoirs are predicted to be low and are known to a high level of certainty. Current approaches to predict CO2 leakage rates assume constant permeability of leakage pathways (e.g., wellbores, faults, fractures). A reactive transport model was developed to account for geochemical alterations that result in permeability evolution of leakage pathways. The one-dimensional reactive transport model was coupled with the basin-scale Estimating Leakage Semi-Analytical (ELSA) model to simulate CO2 and brine leakage through vertical caprock pathways for different CO2 storage reservoir sites and injection scenarios within the Mt. Simon and St. Peter sandstone formations of the Michigan basin. Mineral dissolution in the numerical reactive transport model expands leakage pathways and increases permeability as a result of calcite dissolution by reactions driven by CO2-acidified brine. A geochemical model compared kinetic and equilibrium treatments of calcite dissolution within each grid block for each time step. For a single fracture, we investigated the effect of the reactions on leakage by performing sensitivity analyses of fracture geometry, CO2 concentration, calcite abundance, initial permeability, and pressure gradient. Assuming that calcite dissolution reaches equilibrium at each time step produces unrealistic scenarios of buffering and permeability evolution within fractures. Therefore, the reactive transport model with a kinetic treatment of calcite dissolution was coupled to the ELSA model and used to compare brine and CO2 leakage rates at a variety of potential geologic storage sites within the Michigan basin. The results are used to construct maps based on the susceptibility to geochemically driven increases in leakage rates. These maps should provide useful and easily communicated inputs into decision-making processes for siting geologic CO2

  12. Co-Sequestration Geochemical Modeling: Simple Brine Solution + CO2-O2-SO2

    Science.gov (United States)

    Verba, C.; Kutchko, B. G.; Reed, M. H.

    2012-12-01

    Class H well cement (LaFarge) was exposed to supercritical CO2 to evaluate the impact of brine chemistry on the well cement. Simulated experimental downhole conditions include a pressure of 28.6 MPa and a temperature of 50oC. Brine composition was formulated from the NETL NATCARB database, resulting in a simple solution of 1 M (NaCl, MgCl2, CaCl2). It was determined that the brine chemistry plays a vital role in determining the degree and type of alteration of cement in carbon sequestration conditions. The implications of co-sequestration (CO2/O2/SO2 mixtures) from of oxy-fueled combustion, coal gasification and sour gas have been considered. Geochemical modeling was conducted to understand the interaction between formation brine, cement and co-contaminant gases, using a gas composition of 95.5% CO2, 4% O2, and 1.5% SO2. The modeling results are significant in determining the validity of co-sequestering coal flue gas containing SOx gases or sour hydrocarbon gas which could potentially produce pyrite or other sulfur-bearing species in the cement via mineralization trapping. Thermodynamic components of aqueous species, gases, and minerals were used to calculate the pH and mineral saturation indices using CHIM-XPT. The computed pH of the solution is 4.34. The total sulfate molality within the brine is 0.0095 M. In experimental conditions of 600 mL of brine, 0.0057 moles of sulfate will be converted into 5.7 mL of sulfuric acid. The modeling shows that an excess of 31% O2 forms, indicating that H2S from SO2 disporportionation is oxidized to sulfate, thus no gaseous H2S will form. Remaining SO2 in the experimental headspace has a predicted mole fraction is 10-46. Additional SO2 gas added to the system produces the reaction to precipitate gypsum. Additional gas reactions precipitate gypsum, anhydrite, calcite, and dolomite.

  13. Modeling and Simulation of Metallurgical Process Based on Hybrid Petri Net

    Science.gov (United States)

    Ren, Yujuan; Bao, Hong

    2016-11-01

    In order to achieve the goals of energy saving and emission reduction of iron and steel enterprises, an increasing number of modeling and simulation technologies are used to research and analyse metallurgical production process. In this paper, the basic principle of Hybrid Petri net is used to model and analyse the Metallurgical Process. Firstly, the definition of Hybrid Petri Net System of Metallurgical Process (MPHPNS) and its modeling theory are proposed. Secondly, the model of MPHPNS based on material flow is constructed. The dynamic flow of materials and the real-time change of each technological state in metallurgical process are simulated vividly by using this model. The simulation process can implement interaction between the continuous event dynamic system and the discrete event dynamic system at the same level, and play a positive role in the production decision.

  14. Threat driven modeling framework using petri nets for e-learning system.

    Science.gov (United States)

    Khamparia, Aditya; Pandey, Babita

    2016-01-01

    Vulnerabilities at various levels are main cause of security risks in e-learning system. This paper presents a modified threat driven modeling framework, to identify the threats after risk assessment which requires mitigation and how to mitigate those threats. To model those threat mitigations aspects oriented stochastic petri nets are used. This paper included security metrics based on vulnerabilities present in e-learning system. The Common Vulnerability Scoring System designed to provide a normalized method for rating vulnerabilities which will be used as basis in metric definitions and calculations. A case study has been also proposed which shows the need and feasibility of using aspect oriented stochastic petri net models for threat modeling which improves reliability, consistency and robustness of the e-learning system.

  15. Rank-Defect Adjustment Model for Survey-Line Systematic Errors in Marine Survey Net

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper,the structure of systematic and random errors in marine survey net are discussed in detail and the adjustment method for observations of marine survey net is studied,in which the rank-defect characteristic is discovered first up to now.On the basis of the survey-line systematic error model,the formulae of the rank-defect adjustment model are deduced according to modern adjustment theory.An example of calculations with really observed data is carried out to demonstrate the efficiency of this adjustment model.Moreover,it is proved that the semi-systematic error correction method used at present in marine gravimetry in China is a special case of the adjustment model presented in this paper.

  16. Petri Net-Based R&D Process Modeling and Optimization for Composite Materials

    Directory of Open Access Journals (Sweden)

    Xiaomei Hu

    2013-01-01

    Full Text Available Considering the current R&D process for new composite materials involves some complex details, such as formula design, specimen/sample production, materials/sample test, assessment, materials/sample feedback from customers, and mass production, the workflow model of Petri net-based R&D process for new composite materials’ is proposed. By analyzing the time property of the whole Petri net, the optimized model for new composite materials R&D workflow is further proposed. By analyzing the experiment data and application in some materials R&D enterprise, it is demonstrated that the workflow optimization model shortens the period of R&D on new materials for 15%, definitely improving the R&D efficiency. This indicates the feasibility and availability of the model.

  17. Robust modelling and simulation integration of SIMIO with coloured petri nets

    CERN Document Server

    De La Mota, Idalia Flores; Mujica Mota, Miguel; Angel Piera, Miquel

    2017-01-01

    This book presents for the first time a methodology that combines the power of a modelling formalism such as colored petri nets with the flexibility of a discrete event program such as SIMIO. Industrial practitioners have seen the growth of simulation as a methodology for tacking problems in which variability is the common denominator. Practically all industrial systems, from manufacturing to aviation are considered stochastic systems. Different modelling techniques have been developed as well as mathematical techniques for formalizing the cause-effect relationships in industrial and complex systems. The methodology in this book illustrates how complexity in modelling can be tackled by the use of coloured petri nets, while at the same time the variability present in systems is integrated in a robust fashion. The book can be used as a concise guide for developing robust models, which are able to efficiently simulate the cause-effect relationships present in complex industrial systems without losing the simulat...

  18. Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters.

    Science.gov (United States)

    Liu, Fei; Heiner, Monika; Yang, Ming

    2016-01-01

    Stochastic Petri nets (SPNs) have been widely used to model randomness which is an inherent feature of biological systems. However, for many biological systems, some kinetic parameters may be uncertain due to incomplete, vague or missing kinetic data (often called fuzzy uncertainty), or naturally vary, e.g., between different individuals, experimental conditions, etc. (often called variability), which has prevented a wider application of SPNs that require accurate parameters. Considering the strength of fuzzy sets to deal with uncertain information, we apply a specific type of stochastic Petri nets, fuzzy stochastic Petri nets (FSPNs), to model and analyze biological systems with uncertain kinetic parameters. FSPNs combine SPNs and fuzzy sets, thereby taking into account both randomness and fuzziness of biological systems. For a biological system, SPNs model the randomness, while fuzzy sets model kinetic parameters with fuzzy uncertainty or variability by associating each parameter with a fuzzy number instead of a crisp real value. We introduce a simulation-based analysis method for FSPNs to explore the uncertainties of outputs resulting from the uncertainties associated with input parameters, which works equally well for bounded and unbounded models. We illustrate our approach using a yeast polarization model having an infinite state space, which shows the appropriateness of FSPNs in combination with simulation-based analysis for modeling and analyzing biological systems with uncertain information.

  19. Petri Net Modeling of the Brain Circuit Involved in Aggressive Behavior

    OpenAIRE

    Moreno, Carlos B.; Díaz, José-Luis; Martínez, J. H.

    2015-01-01

    The purpose of this work in to demonstrate the initial results of a research project having as its goal to develop dynamic models of the brain network involved in aggressive behavior. In this way, the complex neural process correlated to basic anger emotions and resulting in aggressive behaviors is purportedly schematized by the use of Petri nets, a work-flow computational tool. Initially, the modeling technique is introduced taking into account the most recent and accepted notion of the neur...

  20. Coordination buyer-supplier in supply chain models from net present value perspective

    OpenAIRE

    Hamontree, Chaowalit

    2014-01-01

    This thesis examines four parts of production and inventory models for buyer-supplier in the supply chain under deterministic conditions. The main objective is to find optimal lot-sizing decisions and inventory policies which derive from the classical inventory and Net Present Value (NPV) framework. Firstly, we study the production and inventory models from the classical framework to identify how to value the holding cost for buyer and supplier in the average profit or cost functions. Secondl...

  1. FINE-GRAINED DISTRIBUTED MULTIMEDIA SYNCHRONIZA- TION MODEL--ENHANCED FUZZY-TIMING PETRI NET

    Institute of Scientific and Technical Information of China (English)

    韩莹洁; 孙永强; 吴哲辉

    2001-01-01

    A fine-grained distributed multimedia synchronization model--Enhanced Fuzzy timing Petri Net was proposed which is good at modeling indeterminacy and fuzzy. To satisfy the need of maximum tolerable jitter, the sufficient conditions are given in intra-object synchronization. Method to find a proper granularity in inter-object synchronization is also given to satisfy skew. Exceptions are detected and corrected as early as possible using restricted blocking method.

  2. JiffyNet: a web-based instant protein network modeler for newly sequenced species.

    Science.gov (United States)

    Kim, Eiru; Kim, Hanhae; Lee, Insuk

    2013-07-01

    Revolutionary DNA sequencing technology has enabled affordable genome sequencing for numerous species. Thousands of species already have completely decoded genomes, and tens of thousands more are in progress. Naturally, parallel expansion of the functional parts list library is anticipated, yet genome-level understanding of function also requires maps of functional relationships, such as functional protein networks. Such networks have been constructed for many sequenced species including common model organisms. Nevertheless, the majority of species with sequenced genomes still have no protein network models available. Moreover, biologists might want to obtain protein networks for their species of interest on completion of the genome projects. Therefore, there is high demand for accessible means to automatically construct genome-scale protein networks based on sequence information from genome projects only. Here, we present a public web server, JiffyNet, specifically designed to instantly construct genome-scale protein networks based on associalogs (functional associations transferred from a template network by orthology) for a query species with only protein sequences provided. Assessment of the networks by JiffyNet demonstrated generally high predictive ability for pathway annotations. Furthermore, JiffyNet provides network visualization and analysis pages for wide variety of molecular concepts to facilitate network-guided hypothesis generation. JiffyNet is freely accessible at http://www.jiffynet.org.

  3. Enabling Grid Computing resources within the KM3NeT computing model

    Directory of Open Access Journals (Sweden)

    Filippidis Christos

    2016-01-01

    Full Text Available KM3NeT is a future European deep-sea research infrastructure hosting a new generation neutrino detectors that – located at the bottom of the Mediterranean Sea – will open a new window on the universe and answer fundamental questions both in particle physics and astrophysics. International collaborative scientific experiments, like KM3NeT, are generating datasets which are increasing exponentially in both complexity and volume, making their analysis, archival, and sharing one of the grand challenges of the 21st century. These experiments, in their majority, adopt computing models consisting of different Tiers with several computing centres and providing a specific set of services for the different steps of data processing such as detector calibration, simulation and data filtering, reconstruction and analysis. The computing requirements are extremely demanding and, usually, span from serial to multi-parallel or GPU-optimized jobs. The collaborative nature of these experiments demands very frequent WAN data transfers and data sharing among individuals and groups. In order to support the aforementioned demanding computing requirements we enabled Grid Computing resources, operated by EGI, within the KM3NeT computing model. In this study we describe our first advances in this field and the method for the KM3NeT users to utilize the EGI computing resources in a simulation-driven use-case.

  4. Enabling Grid Computing resources within the KM3NeT computing model

    Science.gov (United States)

    Filippidis, Christos

    2016-04-01

    KM3NeT is a future European deep-sea research infrastructure hosting a new generation neutrino detectors that - located at the bottom of the Mediterranean Sea - will open a new window on the universe and answer fundamental questions both in particle physics and astrophysics. International collaborative scientific experiments, like KM3NeT, are generating datasets which are increasing exponentially in both complexity and volume, making their analysis, archival, and sharing one of the grand challenges of the 21st century. These experiments, in their majority, adopt computing models consisting of different Tiers with several computing centres and providing a specific set of services for the different steps of data processing such as detector calibration, simulation and data filtering, reconstruction and analysis. The computing requirements are extremely demanding and, usually, span from serial to multi-parallel or GPU-optimized jobs. The collaborative nature of these experiments demands very frequent WAN data transfers and data sharing among individuals and groups. In order to support the aforementioned demanding computing requirements we enabled Grid Computing resources, operated by EGI, within the KM3NeT computing model. In this study we describe our first advances in this field and the method for the KM3NeT users to utilize the EGI computing resources in a simulation-driven use-case.

  5. Speciation of magnesium in monohydrocalcite: XANES, ab initio and geochemical modeling

    Science.gov (United States)

    Fukushi, Keisuke; Suzuki, Yuma; Kawano, Jun; Ohno, Takeshi; Ogawa, Masahiro; Yaji, Toyonari; Takahashi, Yoshio

    2017-09-01

    Monohydrocalcite (MHC: CaCO3·H2O), a rare carbonate mineral formed under surface conditions, is usually observed in nature as containing a variable amount of Mg, with a 0.007-0.45 Mg/Ca mole ratio. The variable Mg composition in MHC is anticipated as a promising proxy to assess paleo-hydrochemistry especially in saline lakes. Although the roles of Mg on the formation and stability of MHC have been studied intensively, the Mg speciation in MHC has remained unclear and controversial. This study examined Mg speciation in MHC using X-ray absorption near edge structure (XANES), ab initio molecular simulation, and geochemical modeling. Mg-XANES spectra of MHC with different Mg/Ca ratios prepared from mixing solutions of Na2CO3, CaCl2 and MgCl2 revealed that the Mg in MHC is a mixture of amorphous Mg carbonate (AMC) and other Mg containing phase. The contribution of AMC to total Mg is negatively correlated to the crystallinity of MHC. Results show that AMC might play a protective role in the crystallization and the transformation to stable calcium carbonates. Ab initio calculation of Mg2+ substitution into MHC showed that a limited amount of Mg2+ can be incorporated into the MHC structure. Six-fold coordination of Mg2+ is substituted for eight-fold coordination of Ca2+ in the MHC structure. The other type of Mg in MHC revealed from the XANES analyses most likely corresponds to the structural Mg in MHC. The contribution of the structural Mg is almost constant at 0.06 in Mg/Ca, representing the limit of solid solubility of Mg in MHC. The solubility products of the MHC with the limit of solid solubility of Mg and the AMC associated with MHC were estimated from the reacted solution compositions. Prediction of the Mg/Ca ratio as a function of the initial solution conditions using solubility reasonably reproduces the observed apparent Mg/Ca ratios in MHC from the present study and earlier studies. The apparent Mg/Ca ratio of MHC is useful to elucidate water chemistry

  6. Applying a semantic information Petri Net modeling method to AUV systems design

    Institute of Scientific and Technical Information of China (English)

    FENG Xiao-ning; WANG Shuo; WANG Zhuo; LIU Qun

    2008-01-01

    This paper informally introduces colored object-oriented Petri Nets(COOPN) with the application of the AUV system. According to the characteristic of the AUV system's running environment,the object-oriented method is used in this paper not only to dispart system modules but also construct the refined running model of AUV system,then the colored Petri Net method is used to establish hierarchically detailed model in order to get the performance analyzing information of the system. After analyzing the model implementation,the errors of architecture designing and function realization can be found. If the errors can be modified on time,the experiment time in the pool can be reduced and the cost can be saved.

  7. Fuzzy reasoning model using fuzzy Petri Nets for the monitoring of robotic assembly

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper presented a fuzzy Petri net model to deal with the monitoring of robotic assembly. Based on the fuzzy Petri net model. All efficient composite reasoning mode was proposed to perform fuzzy reasoning automatically. It can determine whether there exists an antecedent-consequence relationship between two contact states. Furthermore, various types of sensor signals can be converted to the same form of real values between zero and one, and the contradiction among large number, high degree of truth and importance of input conditions can be resolved very well by introducing the weight factors and priorities for sensor signals. Finally, a pegin-the-hole example was given to illustrate the reasonability and feasibility of the proposed model.

  8. Evaluation of Model Results and Measured Performance of Net-Zero Energy Homes in Hawaii: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Norton, P.; Kiatreungwattana, K.; Kelly, K. J.

    2013-03-01

    The Kaupuni community consists of 19 affordable net-zero energy homes that were built within the Waianae Valley of Oahu, Hawaii in 2011. The project was developed for the native Hawaiian community led by the Department of Hawaiian Homelands. This paper presents a comparison of the modeled and measured energy performance of the homes. Over the first year of occupancy, the community as a whole performed within 1% of the net-zero energy goals. The data show a range of performance from house to house with the majority of the homes consistently near or exceeding net-zero, while a few fall short of the predicted net-zero energy performance. The impact of building floor plan, weather, and cooling set point on this comparison is discussed. The project demonstrates the value of using building energy simulations as a tool to assist the project to achieve energy performance goals. Lessons learned from the energy performance monitoring has had immediate benefits in providing feedback to the homeowners, and will be used to influence future energy efficient designs in Hawaii and other tropical climates.

  9. Comparing global models of terrestrial net primary productivity (NPP): Global pattern and differentiation by major biomes

    Science.gov (United States)

    Kicklighter, D.W.; Bondeau, A.; Schloss, A.L.; Kaduk, J.; McGuire, A.D.

    1999-01-01

    Annual and seasonal net primary productivity estimates (NPP) of 15 global models across latitudinal zones and biomes are compared. The models simulated NPP for contemporary climate using common, spatially explicit data sets for climate, soil texture, and normalized difference vegetation index (NDVI). Differences among NPP estimates varied over space and time. The largest differences occur during the summer months in boreal forests (50??to 60??N) and during the dry seasons of tropical evergreen forests. Differences in NPP estimates are related to model assumptions about vegetation structure, model parameterizations, and input data sets.

  10. Geochemical models of melting and magma storage conditions for basalt lava from Santorini Volcano, Greece

    Science.gov (United States)

    Baziotis, Ioannis; Kimura, Jun-Ichi; Pantazidis, Avgoustinos; Klemme, Stephan; Berndt, Jasper; Asimow, Paul

    2017-04-01

    Santorini volcano sits ˜150 km above the Wadati-Benioff zone of the Aegean arc, where the African plate subducts northward beneath the Eurasian continent (Papazachos et al. 2000). Santorini volcano has a long history: activity started ca. 650 ka (mainly rhyolites and rhyodacites), with active pulses following ca. 550 ka (basalt to rhyodacite) and ca. 360 ka (large explosive eruptions of andesite to rhyodacite and minor basalt), culminating in the caldera-forming Bronze-age Minoan event (Druitt et al. 1999). As in many arc volcanoes, scenarios of fractional crystallization with or without mixing between felsic and mafic magmas have been proposed to explain the compositions, textures, and eruptive styles of Santorini products (e.g., Huijsmans & Barton 1989; Montazavi & Sparks 2004; Andújar et al. 2015). Here we focus on a basalt lava from the southern part of Santorini volcano (Balos cove, 36˚ 21.7'N, 25˚ 23.8'E), one of the few basaltic localities in the Aegean arc. The goals are to infer constraints on the magma chamber conditions which lead to mafic eruption at Santorini Volcano and to evaluate the slab and mantle wedge conditions via geochemical and petrological mass balance modelling. We collected and characterised 20 samples for texture (SEM), mineral chemistry (FE-EPMA) and whole-rock chemistry (XRF). The basalts contain phenocrystic olivine (Ol) and clinopyroxene (Cpx) (Santorini basalts exhibit a pilotaxitic to trachytic texture defined by randomly to flow-oriented tabular Pl, respectively. The predominant minerals are calcic Pl (core An78-85 and rim An60-76; 45-50 vol.%), Cpx (En36-48Wo41-44Fs11-21; 10-15 vol.%) and Ol (Fo74-88; 10-12 vol.%). Idiomorphic to subidiomorphic Mt (<10μm diameter) with variable TiO2 contents (1.9-16.5 wt%) is a minor constituent (˜1-2 vol.%) in the less mafic samples. Observed mineralogy and major element chemistry suggest fractionation in a shallow magma chamber. Using the major element chemistry and PRIMACALC2 (Kimura

  11. Evaluation of Cyber Security and Modelling of Risk Propagation with Petri Nets

    Directory of Open Access Journals (Sweden)

    Marcin Szpyrka

    2017-02-01

    Full Text Available This article presents a new method of risk propagation among associated elements. On thebasis of coloured Petri nets, a new class called propagation nets is defined. This class providesa formal model of a risk propagation. The proposed method allows for model relations betweennodes forming the network structure. Additionally, it takes into account the bidirectional relationsbetween components as well as relations between isomorphic, symmetrical components in variousbranches of the network. This method is agnostic in terms of use in various systems and it canbe adapted to the propagation model of any systems’ characteristics; however, it is intentionallyproposed to assess the risk of critical infrastructures. In this paper, as a proof of concept example, weshow the formal model of risk propagation proposed within the project Cyberspace Security ThreatsEvaluation System of the Republic of Poland. In the article, the idea of the method is presented aswell as its use case for evaluation of risk for cyber threats. With the adaptation of Petri nets, it ispossible to evaluate the risk for the particular node and assess the impact of this risk for all relatednodes including hierarchic relations of components as well as isomorphism of elements.

  12. Web Services modeling and composition approach using Objects-Oriented Petri Nets

    Directory of Open Access Journals (Sweden)

    Sofiane Chemaa

    2012-07-01

    Full Text Available Nowadays, with the emergence and the evolution of new technologies, such as e-business, a large number of companies are connected to Internet, and have proposed web services to trade. Web services as presented, are conceptually limited components to relatively simple functionalities. Generally, a single service does not satisfy the users needs that are more and more complex. Therefore, services must be made able to be composed to offer added value services. In this paper, a web services composition approach, modelled by Objects-Oriented Petri nets, is presented. In his context, an expressive algebra, which successfully solves the web services complex composition problem, is proposed. A java tool that allows automating this approach; based on a definite algebra and a G-nets meta-model, proposed by us, is developed.

  13. Experimental, numerical and analytical modelling of a newly developed rockfall protective cable-net structure

    Directory of Open Access Journals (Sweden)

    S. Dhakal

    2011-12-01

    Full Text Available An innovative configuration of pocket-type rockfall protective cable-net structure, known as Long-span Pocket-type Rock-net (LPR, has been developed in Japan. The global performance of the proposed system was initially checked by the experimental (full-scale modelling. Given the various limitations of the physical experiments, particularly for the parametric study to have a detailed understanding of the newly developed system, a reliable and simplified method of numerical modelling is felt necessary. Again, given the sophistication involved with the method of numerical simulation, a yet simplified modelling approach may prove more effective. On top of this background, this paper presents a three-tier modelling of a design of LPR. After physical modelling, which has revealed that the displacement response may be taken more vital for LPR performance, Finite Element based numerical modelling is presented. The programme LS-DYNA is used and the models are calibrated and verified with the element- and structure-level experiments. Finally, a simple analytical modelling consisting of the equivalently linear and elastic, lumped-mass, single-degree-of-freedom system, capable of predicting the global displacement response, is proposed based on the basic principles of conservation of linear momentum and energy. The model is back-calculated and modified from the analyses of the verified numerical model.

  14. Downlink MIMO HetNets: Modeling, Ordering Results and Performance Analysis

    OpenAIRE

    Dhillon, Harpreet S.; Kountouris, Marios; Andrews, Jeffrey G.

    2013-01-01

    We develop a general downlink model for multi-antenna heterogeneous cellular networks (HetNets), where base stations (BSs) across tiers may differ in terms of transmit power, target signal-to-interference-ratio (SIR), deployment density, number of transmit antennas and the type of multi-antenna transmission. In particular, we consider and compare space division multiple access (SDMA), single user beamforming (SU-BF), and baseline single-input single-output (SISO) transmission. For this genera...

  15. User`s guide to the META-Net economic modeling system. Version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Lamont, A.

    1994-11-24

    In a market economy demands for commodities are met through various technologies and resources. Markets select the technologies and resources to meet these demands based on their costs. Over time, the competitiveness of different technologies can change due to the exhaustion of resources they depend on, the introduction of newer, more efficient technologies, or even shifts in user demands. As this happens, the structure of the economy changes. The Market Equilibrium and Technology Assessment Network Modelling System, META{center_dot}Net, has been developed for building and solving multi-period equilibrium models to analyze the shifts in the energy system that may occur as new technologies are introduced and resources are exhausted. META{center_dot}Net allows a user to build and solve complex economic models. It models` a market economy as a network of nodes representing resources, conversion processes, markets, and end-use demands. Commodities flow through this network from resources, through conversion processes and market, to the end-users. META{center_dot}Net then finds the multiperiod equilibrium prices and quantities. The solution includes the prices and quantities demanded for each commodity along with the capacity additions (and retirements) for each conversion process, and the trajectories of resource extraction. Although the changes in the economy are largely driven by consumers` behavior and the costs of technologies and resources, they are also affected by various government policies. These can include constraints on prices and quantities, and various taxes and constraints on environmental emissions. META{center_dot}Net can incorporate many of these mechanisms and evaluate their potential impact on the development of the economic system.

  16. Strategic Design, Optimization, and Modelling Issues of Net-Zero Energy Solar Buildings

    OpenAIRE

    ATHIENITIS, Andreas; Attia, Shady

    2010-01-01

    The design of net-zero energy solar buildings (NZESBs) presents a challenge because there is no established design strategy to systematically reach this goal and many of the available building energy tools have limited applicability for such advanced buildings. This paper reviews current design practice and tools for designing NZESBs through a literature review and a survey. It also discusses modelling issues and presents the procedure used in several redesign and optimization case studies of...

  17. ScaleNet: a literature-based model of scale insect biology and systematics

    OpenAIRE

    García Morales, Mayrolin; Denno, Barbara D.; Miller, Douglass R.; Miller, Gary L.; Ben-Dov, Yair; Hardy, Nate B.

    2016-01-01

    Scale insects (Hemiptera: Coccoidea) are small herbivorous insects found on all continents except Antarctica. They are extremely invasive, and many species are serious agricultural pests. They are also emerging models for studies of the evolution of genetic systems, endosymbiosis and plant-insect interactions. ScaleNet was launched in 1995 to provide insect identifiers, pest managers, insect systematists, evolutionary biologists and ecologists efficient access to information about scale insec...

  18. Tools and data for the geochemical modeling. Thermodynamic data for sulfur species and background salts and tools for the uncertainty analysis; WEDA. Werkzeuge und Daten fuer die Geochemische Modellierung. Thermodynamische Daten fuer Schwefelspezies und Hintergrundsalze sowie Tools zur Unsicherheitsanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, Sven; Schoenwiese, Dagmar; Scharge, Tina

    2015-07-15

    The report on tools and data for the geochemical modeling covers the following issues: experimental methods and theoretical models, design of a thermodynamic model for reduced sulfur species, thermodynamic models for background salts, tools for the uncertainty and sensitivity analyses of geochemical equilibrium modeling.

  19. Spatial distribution and leaching behavior of pollutants from phosphogypsum stocked in a gypstack: Geochemical characterization and modeling.

    Science.gov (United States)

    Bisone, Sara; Gautier, Mathieu; Chatain, Vincent; Blanc, Denise

    2017-05-15

    Phosphogypsum (PPG) is the byproduct of the production of phosphoric acid and phosphate fertilizers from phosphate rocks (PR) by acid digestion. Despite the technical feasibility, the impurities present in this waste make its reuse critical and large amounts of PPG are stockpiled, resulting in the production of polluted acid leachates. The aim of the present study was to characterize the spatial variability and evolution in time of a 20-year-old gypstack and to study the geochemical behavior of the waste in order to assess the best management options. Chemical and mineralogical analyses were performed on core samples taken from 4 different depths of the stack down to 13.5 m. Despite the high homogeneity shown by chemical and mineral characterization, leaching tests revealed a different chemical behavior with depth. pH-dependent leaching tests were also performed to measure the acid neutralization capacity of the studied matrices and to determine the leachability of the elements or pollutants of concern as a function of pH. The study was focused on Ca, Fe Na, Si, Cd and Sr and on F(-), PO4(3-) and SO4(2-) anions. The geochemical modeling of these tests with PHREEQC enabled the identification of the minor phases controlling the solubilization of the elements analyzed. Validation of the model by the simulation of a column leaching test suggested that the model could be used as a predictive tool to assess different management scenarios.

  20. Modeling multicomponent ionic transport in groundwater with IPhreeqc coupling: Electrostatic interactions and geochemical reactions in homogeneous and heterogeneous domains

    Science.gov (United States)

    Muniruzzaman, Muhammad; Rolle, Massimo

    2016-12-01

    The key role of small-scale processes like molecular diffusion and electrochemical migration has been increasingly recognized in multicomponent reactive transport in saturated porous media. In this study, we propose a two-dimensional multicomponent reactive transport model taking into account the electrostatic interactions during transport of charged ions in physically and chemically heterogeneous porous media. The modeling approach is based on the local charge balance and on the description of compound-specific and spatially variable diffusive/dispersive fluxes. The multicomponent ionic transport code is coupled with the geochemical code PHREEQC-3 by utilizing the IPhreeqc module, thus enabling to perform the geochemical calculations included in the PHREEQC's reaction package. The multicomponent reactive transport code is benchmarked with different 1-D and 2-D transport problems. Successively, conservative and reactive transport examples are presented to demonstrate the capability of the proposed model to simulate transport of charged species in heterogeneous porous media with spatially variable physical and chemical properties. The results reveal that the Coulombic cross-coupling between dispersive fluxes can significantly influence conservative as well as reactive transport of charged species both at the laboratory and at the field scale.

  1. SilMush: A procedure for modeling of the geochemical evolution of silicic magmas and granitic rocks

    Science.gov (United States)

    Hertogen, Jan; Mareels, Joyce

    2016-07-01

    A boundary layer crystallization modeling program is presented that specifically addresses the chemical fractionation in silicic magma systems and the solidification of plutonic bodies. The model is a Langmuir (1989) type approach and does not invoke crystal settling in high-viscosity silicic melts. The primary aim is to model a granitic rock as a congealed crystal-liquid mush, and to integrate major element and trace element modeling. The procedure allows for some exploratory investigation of the exsolution of H2O-fluids and of the fluid/melt partitioning of trace elements. The procedure is implemented as a collection of subroutines for the MS Excel spreadsheet environment and is coded in the Visual Basic for Applications (VBA) language. To increase the flexibility of the modeling, the procedure is based on discrete numeric process simulation rather than on solution of continuous differential equations. The program is applied to a study of the geochemical variation within and among three granitic units (Senones, Natzwiller, Kagenfels) from the Variscan Northern Vosges Massif, France. The three units cover the compositional range from monzogranite, over syenogranite to alkali-feldspar granite. An extensive set of new major element and trace element data is presented. Special attention is paid to the essential role of accessory minerals in the fractionation of the Rare Earth Elements. The crystallization model is able to reproduce the essential major and trace element variation trends in the data sets of the three separate granitic plutons. The Kagenfels alkali-feldspar leucogranite couples very limited variation in major element composition to a considerable and complex variation of trace elements. The modeling results can serve as a guide for the reconstruction of the emplacement sequence of petrographically distinct units. Although the modeling procedure essentially deals with geochemical fractionation within a single pluton, the modeling results bring up a

  2. A Formal Model of OSI X.25/FR Gateway Based on High Level Petri Net

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Specification and validation of protocol conversion in a gatewayis a difficult problem in protocol engineering. During design and implementation of an OSI X.25/FR gateway, a high-level Petri Net called EPr/TN is introduced as a formal specification tool to solve this problem. A formal model of the gateway is constructed by using Epr/TN. Based on this model, the process of protocol conversion and data transmission in the gateway are analyzed and validated. With object-oriented techniques, this model is also utilized in the software development of the gateway.

  3. Model-Based Requirements Analysis for Reactive Systems with UML Sequence Diagrams and Coloured Petri Nets

    DEFF Research Database (Denmark)

    Tjell, Simon; Lassen, Kristian Bisgaard

    2008-01-01

    In this paper, we describe a formal foundation for a specialized approach to automatically checking traces against real-time requirements. The traces are obtained from simulation of Coloured Petri Net (CPN) models of reactive systems. The real-time requirements are expressed in terms...... of a derivative of UML 2.0 high-level Sequence Diagrams. The automated requirement checking is part of a bigger tool framework in which VDM++ is applied to automatically generate initial CPN models based on Problem Diagrams. These models are manually enhanced to provide behavioral descriptions of the environment...

  4. Petri net-based modelling of human-automation conflicts in aviation.

    Science.gov (United States)

    Pizziol, Sergio; Tessier, Catherine; Dehais, Frédéric

    2014-01-01

    Analyses of aviation safety reports reveal that human-machine conflicts induced by poor automation design are remarkable precursors of accidents. A review of different crew-automation conflicting scenarios shows that they have a common denominator: the autopilot behaviour interferes with the pilot's goal regarding the flight guidance via 'hidden' mode transitions. Considering both the human operator and the machine (i.e. the autopilot or the decision functions) as agents, we propose a Petri net model of those conflicting interactions, which allows them to be detected as deadlocks in the Petri net. In order to test our Petri net model, we designed an autoflight system that was formally analysed to detect conflicting situations. We identified three conflicting situations that were integrated in an experimental scenario in a flight simulator with 10 general aviation pilots. The results showed that the conflicts that we had a-priori identified as critical had impacted the pilots' performance. Indeed, the first conflict remained unnoticed by eight participants and led to a potential collision with another aircraft. The second conflict was detected by all the participants but three of them did not manage the situation correctly. The last conflict was also detected by all the participants but provoked typical automation surprise situation as only one declared that he had understood the autopilot behaviour. These behavioural results are discussed in terms of workload and number of fired 'hidden' transitions. Eventually, this study reveals that both formal and experimental approaches are complementary to identify and assess the criticality of human-automation conflicts. Practitioner Summary: We propose a Petri net model of human-automation conflicts. An experiment was conducted with general aviation pilots performing a scenario involving three conflicting situations to test the soundness of our formal approach. This study reveals that both formal and experimental approaches

  5. Testing geochemical models of bentonite pore water evolution against laboratory experimental data

    Science.gov (United States)

    Savage, David; Arthur, Randy; Watson, Claire; Wilson, James; Strömberg, Bo

    The determination of a bentonite pore water composition and understanding its evolution with time underpins many radioactive waste disposal issues, such as buffer erosion, canister corrosion, and radionuclide solubility, sorption, and diffusion, inter alia. Previous modelling approaches have tended to ignore clay dissolution-precipitation reactions, a consequence of which is that montmorillonite is theoretically preserved indefinitely in the repository system. Here, we investigate the applicability of an alternative clay pore fluid evolution model, that incorporates clay dissolution-precipitation reactions as an integral component and test it against well-characterised laboratory experimental data, where key geochemical parameters, Eh and pH, have been measured directly in compacted bentonite. Simulations have been conducted using different computer codes (Geochemist’s Workbench, PHREEQC, and QPAC) to test the applicability of this model. Thermodynamic data for the Gibb’s free energy of formation of MX-80 smectite used in the calculations were estimated using two different methods (‘Polymer’ and ‘Vieillard’ Models). Simulations of ‘end-point’ pH measurements in batch bentonite-water slurry experiments showed different pH values according to the complexity of the system studied. The most complete system investigated revealed pH values were a strong function of partial pressure of carbon dioxide, with pH increasing with decreasing PCO 2 (with log PCO 2 values ranging from -3.5 to -7.5 bars produced pH values ranging from 7.9 to 9.6). A second set of calculations investigated disequilibrium between clay and pore fluid in laboratory squeezing cell tests involving pure water (pH = 9.0) or a 1 M NaOH solution (pH = 12.1). Simulations carried out for 100 days (the same timescale as the experiments) showed that smectite remained far from equilibrium throughout, and that the lowering of pH due to smectite hydrolysis was trivial. However, extending the

  6. Description and evaluation of a net energy intake model as a function of dietary chewing index

    DEFF Research Database (Denmark)

    Jensen, L.M.; Markussen, B.; Nielsen, N.I.

    2016-01-01

    Previously, a linear relationship has been found between net energy intake (NEI) and dietary chewing index (CI) of the diet for different types of cattle. Therefore, we propose to generalize and calibrate this relationship into a new model for direct prediction of NEI by dairy cows from CI values...... and a was estimated to have a value of 2, implying a constant maximum daily chewing time. The intercept NEI0 in the regression of NEI on CINE may be interpreted as metabolic net energy intake capacity of the cows fed without physical constraints on intake. Based on experimental data, the maximum chewing time...... was estimated as 1/(4 × k). The NEI0 values were parameterized as a linear function of metabolic body size, energy-corrected milk yield (kg/d), days in milk, and days in milk squared. Prediction accuracy was evaluated by mean square prediction error (MSPE) and its decomposition into central tendency, regression...

  7. Description and evaluation of a net energy intake model as a function of dietary chewing index

    DEFF Research Database (Denmark)

    Jensen, Laura Mie; Markussen, Bo; Nielsen, N. I.

    2016-01-01

    Previously, a linear relationship has been found between net energy intake (NEI) and dietary chewing index (CI) of the diet for different types of cattle. Therefore, we propose to generalize and calibrate this relationship into a new model for direct prediction of NEI by dairy cows from CI values...... a value of 2, implying a constant maximum daily chewing time. The intercept NEI0 in the regression of NEI on CINE may be interpreted as metabolic net energy intake capacity of the cows fed without physical constraints on intake. Based on experimental data, the maximum chewing time was estimated as 1....../(4 × k). The NEI0 values were parameterized as a linear function of metabolic body size, energy-corrected milk yield (kg/d), days in milk, and days in milk squared. Prediction accuracy was evaluated by mean square prediction error (MSPE) and its decomposition into central tendency, regression...

  8. The Relevance of Value Net Integrator and Shared Infrastructure Business Models in Managing Chronic Conditions

    Directory of Open Access Journals (Sweden)

    Susan Lambert

    2005-11-01

    Full Text Available There is widespread support for chronic condition management (CCM programs that require a multi-disciplinary, care-team approach. Implementation of such programs represents a paradigm shift in primary care service delivery and has significant resource implications for the general practice. Integral to the widespread uptake of care-team based CCM is information collection, storage and dissemination amongst the care-team members. This paper looks to ebusiness models for assistance in understanding the requirements of general practitioners (GPs in providing multi-disciplinary team care to patients with chronic conditions. The role required of GPs in chronic condition management is compared to that of a value net integrator. The essential characteristics of value net integrators are identified and compared to those of GPs providing multi-disciplinary team care to patients with chronic conditions. It is further suggested that a shared infrastructure is required.

  9. Designing a mathematical model of management techniques (TQM, BPR in Zahedan , weave fishing net industries

    Directory of Open Access Journals (Sweden)

    Dr.Baqer Kord, Dr. Habibollah Salarzehi, Hamed Aramesh, Somayeh Mousavi

    2010-10-01

    Full Text Available Currently reengineering and Total Quality Management (TQM techniques known improvement in organizations. in this research initially a Mathematical model was designed to find out the main factors in relative reengineering and TQM. Based on finding factors of Model, a 40 element questionary formed and the questionnaire distributed among the staff of fishing net factory in a random order, finding by using of SPSS, the data analyzed and concluding Remark shows the installation and acceptance of TQM by using reengineering is possible to the factory.

  10. Symmetry-enriched string nets: Exactly solvable models for SET phases

    Science.gov (United States)

    Heinrich, Chris; Burnell, Fiona; Fidkowski, Lukasz; Levin, Michael

    2016-12-01

    We construct exactly solvable models for a wide class of symmetry-enriched topological (SET) phases. Our construction applies to two-dimensional (2D) bosonic SET phases with finite unitary on-site symmetry group G and we conjecture that our models realize every phase in this class that can be described by a commuting projector Hamiltonian. Our models are designed so that they have a special property: If we couple them to a dynamical lattice gauge field with gauge group G , the resulting gauge theories are equivalent to string-net models. This property is what allows us to analyze our models in generality. As an example, we present a model for a phase with the same anyon excitations as the toric code and with a Z2 symmetry which exchanges the e and m type anyons. We further illustrate our construction with a number of additional examples.

  11. Geochemical Modeling of Trivalent Chromium Migration in Saline-Sodic Soil during Lasagna Process: Impact on Soil Physicochemical Properties

    Directory of Open Access Journals (Sweden)

    Salihu Lukman

    2014-01-01

    Full Text Available Trivalent Cr is one of the heavy metals that are difficult to be removed from soil using electrokinetic study because of its geochemical properties. High buffering capacity soil is expected to reduce the mobility of the trivalent Cr and subsequently reduce the remedial efficiency thereby complicating the remediation process. In this study, geochemical modeling and migration of trivalent Cr in saline-sodic soil (high buffering capacity and alkaline during integrated electrokinetics-adsorption remediation, called the Lasagna process, were investigated. The remedial efficiency of trivalent Cr in addition to the impacts of the Lasagna process on the physicochemical properties of the soil was studied. Box-Behnken design was used to study the interaction effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil pH, electroosmotic volume, soil electrical conductivity, current, and remedial efficiency of trivalent Cr in saline-sodic soil that was artificially spiked with Cr, Cu, Cd, Pb, Hg, phenol, and kerosene. Overall desirability of 0.715 was attained at the following optimal conditions: voltage gradient 0.36 V/cm; polarity reversal rate 17.63 hr; soil pH 10.0. Under these conditions, the expected trivalent Cr remedial efficiency is 64.75 %.

  12. Net Operations

    Institute of Scientific and Technical Information of China (English)

    蒋昌俊; 吴哲辉

    1992-01-01

    Two kinds of net operations.addition and Cartesian production of P/T nets,are introduced.They are defined on the set of underlying net of P/T systems.The conditions for preserving structural properties of Petri net after these operations are discussed.It is shown that the set of P/T nets forms and Abelian group for net addition operation and the inverse net of a P/T net in usual meaning of net theory is exactly the inverse of this P/T net as an element of the P/T net group;and that the set of P/T nets forms an Abelian ring for net addition and Caresian product operations.

  13. e-Commerce and supply chains: Modelling of dynamics through fuzzy enhanced high level petri net

    Indian Academy of Sciences (India)

    Vipul Jain; S Wadhwa; S G Deshmukh

    2005-04-01

    Although information plays a major role in effective functioning of supply chain networks (SCNs), studies that deal specifically with the dynamics of supply chains are few. This problem is relatively new since fast communications and the means to employ it for effective management of supply chains did not exist till recently. In order to provide a vehicle for dynamic modelling and analysis of supply chain operations in vague and uncertain environments, we propose a fuzzy enhanced high level petri net (FEHLPN) model. The proposed model captures the capability of petri nets for graphical and analytical representation of dynamic SCNs with the management of uncertain information provided by fuzzy logic. The dynamics associated with two production planning and control policies are modelled, viz. make-to-stock and assemble-to-order in vague and ambiguous situations in electronic commerce environment. A fuzzy set and fuzzy truth-values are attached to an uncertain fuzzy token to model imprecision and uncertainty. The proposed FEHLPN incorporates essential aspects of rule-based systems, such as conservation of facts, refraction, and closed-world assumption.

  14. Generalized stochastic Petri nets based models for performance analysis of communication networks of IEC61850 system

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong; RU Feng; XUE Jun-yi

    2006-01-01

    In this paper, data streams are classified into four types conforming to a standardized infrastructure of communication networks for a substation automation system (SAS) based on IEC61850 system. The data exchanged on the net are demonstrated to be stochastic according to investigation on the Ethernet communication principles. Four generalized stochastic Petri nets (GSPN) based models for performance analysis of communication networks of IEC61850 system are developed based on the three-level structure of SAS, different time requirements of the four data streams and different networks topology for different voltage level. The GSPN-based model associated with immediate and exponential transitions is proven to be theoretically isomorphic with Markov chain; hence we apply the mathematic methods of performance evaluation contained in Markov chain to the GSPN models proposed. The computer simulation of the model including only sample value data streams shows that it can meet performance evaluation needs of communication networks of IEC61850 system. Further researches should be focused on the performance of the other three models to explain clear how those different data streams are interrelated to and interact on each other.

  15. Actualistic and Geochemical Modeling of Reservoir Rock, CO2 and Formation Fluid Interaction, Citronelle Oil Field, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Weislogel, Amy [West Virginia Univ., Morgantown, WV (United States)

    2014-01-31

    This report includes description of the Citronelle field study area and the work carried out in the project to characterize the geology and composition of reservoir rock material and to collect an analyze the geochemical composition of produced fluid waters from the Citronelle field. Reservoir rock samples collected from well bore core were made into thin-sections and assessed for textural properties, including pore types and porosity distribution. Compositional framework grain modal data were collected via point-counting, and grain and cement mineralogy was assessed using SEM-EDS. Geochemistry of fluid samples is described and modeled using PHREEQC. Composition of rock and produced fluids were used as inputs for TOUGHREACT reactive transport modeling, which determined the rock-fluid system was in disequilibrium.

  16. Actualistic and Geochemical Modeling of Reservoir Rock, CO2 and Formation Fluid Interaction, Citronelle Oil Field, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Weislogel, Amy

    2014-01-31

    This report includes description of the Citronelle field study area and the work carried out in the project to characterize the geology and composition of reservoir rock material and to collect an analyze the geochemical composition of produced fluid waters from the Citronelle field. Reservoir rock samples collected from well bore core were made into thin-sections and assessed for textural properties, including pore types and porosity distribution. Compositional framework grain modal data were collected via point-counting, and grain and cement mineralogy was assessed using SEM-EDS. Geochemistry of fluid samples is described and modeled using PHREEQC. Composition of rock and produced fluids were used as inputs for TOUGHREACT reactive transport modeling, which determined the rock-fluid system was in disequilibrium.

  17. Development of a geochemical model to predict leachate water quality associated with coal mining practices / Karl Nicolaus van Zweel

    OpenAIRE

    2015-01-01

    South Africa mines coal to supply in the growing energy demands of the country. A majority of these mines are opencast resulting in back filled pits and above ground disposal facilities. Leachate emanating from these disposal sites are saline and in most cases highly acidic. Currently the standard testing procedure to quantify expected leachate qualities include Acid Base Accounting (ABA), Net-acid Generating test (NAG), static-and kinetic leaching. The aim of this study is to model standa...

  18. Petri nets in Snoopy: a unifying framework for the graphical display, computational modelling, and simulation of bacterial regulatory networks.

    Science.gov (United States)

    Marwan, Wolfgang; Rohr, Christian; Heiner, Monika

    2012-01-01

    Using the example of phosphate regulation in enteric bacteria, we demonstrate the particular suitability of stochastic Petri nets to model biochemical phenomena and their simulative exploration by various features of the software tool Snoopy.

  19. INEEL Subregional Conceptual Model Report Volume 2: Summary of Existing Knowledge of Geochemical Influences on the Fate and Transport of Contaminants in the Subsurface at the INEEL

    Energy Technology Data Exchange (ETDEWEB)

    Paul L. Wichlacz; Robert C. Starr; Brennon Orr

    2003-09-01

    This document summarizes previous descriptions of geochemical system conceptual models for the vadose zone and groundwater zone (aquifer) beneath the Idaho National Engineering and Environmental Laboratory (INEEL). The primary focus is on groundwater because contaminants derived from wastes disposed at INEEL are present in groundwater, groundwater provides a pathway for potential migration to receptors, and because geochemical characteristics in and processes in the aquifer can substantially affect the movement, attenuation, and toxicity of contaminants. The secondary emphasis is perched water bodies in the vadose zone. Perched water eventually reaches the regional groundwater system, and thus processes that affect contaminants in the perched water bodies are important relative to the migration of contaminants into groundwater. Similarly, processes that affect solutes during transport from nearsurface disposal facilities downward through the vadose zone to the aquifer are relevant. Sediments in the vadose zone can affect both water and solute transport by restricting the downward migration of water sufficiently that a perched water body forms, and by retarding solute migration via ion exchange. Geochemical conceptual models have been prepared by a variety of researchers for different purposes. They have been published in documents prepared by INEEL contractors, the United States Geological Survey (USGS), academic researchers, and others. The documents themselves are INEEL and USGS reports, and articles in technical journals. The documents reviewed were selected from citation lists generated by searching the INEEL Technical Library, the INEEL Environmental Restoration Optical Imaging System, and the ISI Web of Science databases. The citation lists were generated using the keywords ground water, groundwater, chemistry, geochemistry, contaminant, INEL, INEEL, and Idaho. In addition, a list of USGS documents that pertain to the INEEL was obtained and manually searched

  20. Modeling and Optimizing Energy Utilization of Steel Production Process: A Hybrid Petri Net Approach

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2013-01-01

    Full Text Available The steel industry is responsible for nearly 9% of anthropogenic energy utilization in the world. It is urgent to reduce the total energy utilization of steel industry under the huge pressures on reducing energy consumption and CO2 emission. Meanwhile, the steel manufacturing is a typical continuous-discrete process with multiprocedures, multiobjects, multiconstraints, and multimachines coupled, which makes energy management rather difficult. In order to study the energy flow within the real steel production process, this paper presents a new modeling and optimization method for the process based on Hybrid Petri Nets (HPN in consideration of the situation above. Firstly, we introduce the detailed description of HPN. Then the real steel production process from one typical integrated steel plant is transformed into Hybrid Petri Net model as a case. Furthermore, we obtain a series of constraints of our optimization model from this model. In consideration of the real process situation, we pick the steel production, energy efficiency and self-made gas surplus as the main optimized goals in this paper. Afterwards, a fuzzy linear programming method is conducted to obtain the multiobjective optimization results. Finally, some measures are suggested to improve this low efficiency and high whole cost process structure.

  1. The evolution of the magmatic arc of Southern Peru (200-60 Ma), Arequipa area: insight from geochemical modeling

    Science.gov (United States)

    Demouy, S.; Benoit, M.; De Saint Blanquat, M.; Brunet, P.

    2012-12-01

    Cordilleran-type batholiths are built by prolonged arc activity along continental margins and may provide detailed magmatic records of the subduction system evolution. The magmas produced in subduction context involve both mantellic and crustal end members and are subject to various petrological processes. The MASH zones (Hildreth and Moorbath, 1988), at the basis of the continental crust, are the best places for the genesis of such hybrid magmas. The various geochemical signatures observed in the plutonic rocks, may also be attributed to source heterogeneities or generated by subsequent petrological processes. This study has focused in the Arequipa section of the Coastal Batholith of Southern Peru (200-60 Ma), in an area extending over 80x40 km. Major and trace elements as well as Sr and Nd isotopic analyses were performed in a set of 100 samples ranging from gabbro to granite. The obtained data highlight the wide heterogeneity of the geochemical signatures that is not related to the classification of the rocks. In first step, Rb/Sr systematic was used to isolate a set of samples plotting along a Paleocene isochron and defining a cogenetic suite. This suite appears to have evolved by simple fractional crystallization. By using reverse modeling, the parameters controlling the fractional crystallization process were defined, as partition coefficients, initial concentrations and amount of fractional crystallization. The other magmatic suites display a wide range of isotopic and geochemical signatures. To explain this heterogeneity, a model involving competition between fractional crystallization and magma mixing into MASH zones was proposed. A large range of hybrid magma types is potentially generated during the maturation of the system, but this range tends to disappear as fractionation and mixing occurs. Finally the model predicts the genesis of a homogeneous reservoir created at depth, from which magmas may evolve only by fractional crystallization. Therefore

  2. Modeling the Net Ecosystem Carbon Balance and Net Ecosystem Exchange of Agroecosystems of the Mid-Continent Intensive Campaign Region during 2000-2008

    Science.gov (United States)

    Izaurralde, R. C.; Zhang, X.; Post, W. M.; Thomson, A. M.; West, T. O.; Williams, J. R.; Manowitz, D.; Nichols, J.; Bandaru, V.; Doraiswamy, P. C.

    2009-12-01

    The terrestrial ecosystem model EPIC (Environment Policy Integrated Climate) is used to simulate the Net Ecosystem Carbon Balance (NECB) and Net Ecosystem Exchange (NEE) in the Mid-Continent Intensive Campaign Region during 2000-2008. EPIC simulates NECB as the difference between C additions (surface and subsurface litter, organic amendments) and C losses (harvest, heterotrophic respiration, soil erosion, and leaching), and NEE as the difference between net primary productivity and heterotrophic respiration. We used the USDA Crop Data Layer to delineate croplands and pasturelands, NCEP Reanalysis data to construct weather files, the SSURGO database to build soil layer files, the NRI database to build management files, and the CTIC database to capture the evolution of tillage practices during the study period. Each site is simulated multiple times by varying input parameters in order to estimate output uncertainty. Simulations of NECB and NEE are aggregated to and reported at the county scale in order to be compared with C flux results obtained using atmospheric inversion methods.

  3. Optimal management of reconfigurable manufacturing system modeling with Petri nets developed three-dimensional - RPD3D

    Science.gov (United States)

    Teodor, F.; Marinescu, V.; Epureanu, A.

    2016-11-01

    Modeling of reconfigurable manufacturing systems would have done using existing Petri net types, but the complexity and dynamics of the new manufacturing system, mainly data reconfiguration feature, required looking for a more compact representation with many variables that to model as accurately not only the normal operation of the production system but can capture and model and reconfiguration process. Thus, it was necessary to create a new class of Petri nets, called RPD3D (Developed Petri nets with three dimensional) showing the name of both lineage (new class derived from Petri nets developed, created in 2000 by Prof. Dr. Ing Vasile Marinescu in his doctoral thesis) [1], but the most important of the new features defining (transformation from one 2D model into a 3D model).The idea was to introduce the classical model of a Petri third dimension to be able to overlay multiple levels (layers) formed in 2D or 3D Petri nets that interact with each other (receiving or giving commands to enable or disable the various modules together simulating the operation of reconfigurable manufacturing systems). The aim is to present a new type of Petri nets called RPD3D - Developed Petri three-dimensional model used for optimal control and simulation of reconfigurable manufacturing systems manufacture of products such systems.

  4. Smart Kd-values, their uncertainties and sensitivities - Applying a new approach for realistic distribution coefficients in geochemical modeling of complex systems.

    Science.gov (United States)

    Stockmann, M; Schikora, J; Becker, D-A; Flügge, J; Noseck, U; Brendler, V

    2017-08-23

    One natural retardation process to be considered in risk assessment for contaminants in the environment is sorption on mineral surfaces. A realistic geochemical modeling is of high relevance in many application areas such as groundwater protection, environmental remediation, or disposal of hazardous waste. Most often concepts with constant distribution coefficients (Kd-values) are applied in geochemical modeling with the advantage to be simple and computationally fast, but not reflecting changes in geochemical conditions. In this paper, we describe an innovative and efficient method, where the smart Kd-concept, a mechanistic approach mainly based on surface complexation modeling, is used (and modified for complex geochemical models) to calculate and apply realistic distribution coefficients. Using the geochemical speciation code PHREEQC, multidimensional smart Kd-matrices are computed as a function of varying (or uncertain) environmental conditions. On the one hand, sensitivity and uncertainty statements for the distribution coefficients can be derived. On the other hand, smart Kd-matrices can be used in reactive transport (or migration) codes (not shown here). This strategy has various benefits: (1) rapid computation of Kd-values for large numbers of environmental parameter combinations; (2) variable geochemistry is taken into account more realistically; (3) efficiency in computing time is ensured, and (4) uncertainty and sensitivity analysis are accessible. Results are presented exemplarily for the sorption of uranium(VI) onto a natural sandy aquifer material and are compared to results based on the conventional Kd-concept. In general, the sorption behavior of U(VI) in dependence of changing geochemical conditions is described quite well. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. A Method for Modeling the Virtual Instrument Automatic Test System Based on the Petri Net

    Institute of Scientific and Technical Information of China (English)

    MA Min; CHEN Guang-ju

    2005-01-01

    Virtual instrument is playing the important role in automatic test system. This paper introduces a composition of a virtual instrument automatic test system and takes the VXIbus based a test software platform which is developed by CAT lab of the UESTC as an example. Then a method to model this system based on Petri net is proposed. Through this method, we can analyze the test task scheduling to prevent the deadlock or resources conflict. At last, this paper analyzes the feasibility of this method.

  6. Geochemical modeling and multivariate statistical evaluation of trace elements in arsenic contaminated groundwater systems of Viterbo Area, (Central Italy).

    Science.gov (United States)

    Sappa, Giuseppe; Ergul, Sibel; Ferranti, Flavia

    2014-01-01

    Contamination of groundwater by naturally occurring arsenic has recently become a disturbing environmental problem in Viterbo area, Central Italy. Arsenic concentrations in most of the public supply networks exceed the maximum allowable limit of 10 μg/l (WHO) for drinking water. The primary purpose of this paper is to obtain a better understanding of the factors contributing to the high levels of As in water supply networks. This study focuses on (a) the determination of basic hydrochemical characteristics of groundwater, (b) the identification of the major sources and processes controlling the As contamination in public supply networks, (c) to find out possible relationships among the As and other trace elements through principal component analysis (PCA). Groundwater samples from public water supply wells and springs were collected and analysed for physico-chemical parameters and trace elements. Springs and well water samples are predominantly of the Na-HCO3, Na -Ca-HCO3 and Ca-HCO3 types and the highest arsenic concentrations were observed in Na-HCO3 type water. Eh-pH diagrams reveal that H2AsO4 (-) and HAsO4 (2-), As(V) arsenate, are the dominating As species highlighting slightly to moderately oxidizing conditions. Geochemical modeling indicates that arsenic-bearing phases were undersaturated in the groundwater, however most of the samples were saturated with respect to Fe (i.e. magnetite, hematite and goethite) and Al (diaspore and boehmite) oxide and hydroxide minerals. Concentrations of As, Li, B, Co, Sr, Mo, U and Se are highly correlated (r > 0.7) with each other, however in some groundwater samples As show also good correlations (r > 0.5) with Fe and Mn elements reflecting the relationships among the trace elements result from different geochemical processes. Evaluation of the principal component (PCA) analysis and geochemical modeling suggest that the occurrence of As and other trace element concentrations in groundwater are probably derived

  7. High performance hybrid functional Petri net simulations of biological pathway models on CUDA.

    Science.gov (United States)

    Chalkidis, Georgios; Nagasaki, Masao; Miyano, Satoru

    2011-01-01

    Hybrid functional Petri nets are a wide-spread tool for representing and simulating biological models. Due to their potential of providing virtual drug testing environments, biological simulations have a growing impact on pharmaceutical research. Continuous research advancements in biology and medicine lead to exponentially increasing simulation times, thus raising the demand for performance accelerations by efficient and inexpensive parallel computation solutions. Recent developments in the field of general-purpose computation on graphics processing units (GPGPU) enabled the scientific community to port a variety of compute intensive algorithms onto the graphics processing unit (GPU). This work presents the first scheme for mapping biological hybrid functional Petri net models, which can handle both discrete and continuous entities, onto compute unified device architecture (CUDA) enabled GPUs. GPU accelerated simulations are observed to run up to 18 times faster than sequential implementations. Simulating the cell boundary formation by Delta-Notch signaling on a CUDA enabled GPU results in a speedup of approximately 7x for a model containing 1,600 cells.

  8. Game Coloured Petri Nets

    DEFF Research Database (Denmark)

    Westergaard, Michael

    2006-01-01

    This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachability...... analysis of this net class, and an application of game coloured Petri nets to automatically generate easy-to-understand visualizations of the model by exploiting the knowledge that some parts of the model are not interesting from a visualization perspective (i.e. they are part of the environment...

  9. SteatoNet: the first integrated human metabolic model with multi-layered regulation to investigate liver-associated pathologies.

    Directory of Open Access Journals (Sweden)

    Adviti Naik

    2014-12-01

    Full Text Available Current state-of-the-art mathematical models to investigate complex biological processes, in particular liver-associated pathologies, have limited expansiveness, flexibility, representation of integrated regulation and rely on the availability of detailed kinetic data. We generated the SteatoNet, a multi-pathway, multi-tissue model and in silico platform to investigate hepatic metabolism and its associated deregulations. SteatoNet is based on object-oriented modelling, an approach most commonly applied in automotive and process industries, whereby individual objects correspond to functional entities. Objects were compiled to feature two novel hepatic modelling aspects: the interaction of hepatic metabolic pathways with extra-hepatic tissues and the inclusion of transcriptional and post-transcriptional regulation. SteatoNet identification at normalised steady state circumvents the need for constraining kinetic parameters. Validation and identification of flux disturbances that have been proven experimentally in liver patients and animal models highlights the ability of SteatoNet to effectively describe biological behaviour. SteatoNet identifies crucial pathway branches (transport of glucose, lipids and ketone bodies where changes in flux distribution drive the healthy liver towards hepatic steatosis, the primary stage of non-alcoholic fatty liver disease. Cholesterol metabolism and its transcription regulators are highlighted as novel steatosis factors. SteatoNet thus serves as an intuitive in silico platform to identify systemic changes associated with complex hepatic metabolic disorders.

  10. A two Layer Convecting Mantle With Exchange : A Unified Model Based on Geochemical, Seismic and Heat Flow Observations

    Science.gov (United States)

    Allègre, C. J.; Jaupart, C.; Nolet, G.

    2007-12-01

    The question of layered versus whole mantle convection has been pending since early models of mantle convection (Oxburgh and Turcotte, 1967; McKenzie and Richter, 1978). In a first phase, layered mantle models appeared to be the winners, because they explained most of geochemical observations. They of course also explained the seismic focal solutions (compressive/ non compressive) in subducting plate and the heat flow constraints (Richter, 1980). Later on, the discovery that slabs could penetrate the lower mantle was considered as proof of whole mantle convection. Most numerical experiments were then developed in this context, overlooking many geochemical observations such as rare gas isotopes or radioactive elements. In this presentation, we will examine the different data one by one. a) geochemical constraints include the budget equations for Sr, Nd, Hf, isotopes, the budget equation for He, Ne, Ar, the budget for heat producing elements U, Th, K (including Th/U and K/U ratios). (Allègre and al., 1979, 1982; De Paolo and Wasserburg, 1977; O'Nions and al.,1977). b) Constrains linking geochemical observations and geodynamics. How the so-called depleted mantle is generated ? Continuities and affinities between MORB and OIB, including the Dupal and Non Dupal provinces: The non-pristine source for OIB based on Pb isotope data. The marble cake structure for upper mantle. Continental crust recycling via sediments and delamination processes. In thise respect, we emphasize the difference in statistical variance of isotope or trace element ratios in the different/types of basalts reflecting the difference in stirring intensity in their sources. We also use information from extinct radioactivities 142Nd and 129Xe. In each case, we estimate the errors for measurements and models. c) The seismic evidence of slab penetration into the lower mantle are from Creager and Jordan(1984) to Van der Hilst et al.(1991), Sparkman and al.(1993), with the counter example of non

  11. Estimating the carrying capacity of green mussel cultivation by using net nutrient removal model.

    Science.gov (United States)

    Srisunont, Chayarat; Babel, Sandhya

    2016-11-15

    This study aims to evaluate the nutrient removal potential and carrying capacity of green mussel cultivation by using the mass balance model. The developed model takes into consideration the green mussel growth rate, density and chlorophyll a concentration. The data employed in this study were based on culture conditions at Sriracha Fisheries Research Station, Thailand. Results show that net nutrient removal by green mussel is 3302, 380, and 124mg/year/indv for carbon, nitrogen, and phosphorus respectively. The carrying capacity of green mussel cultivation was found to be 300indv/m(2) based on chlorophyll a concentration which will not release phosphorus in the water environment beyond the standard (45μg-PO4(-3)-P/L). Higher chlorophyll a concentration results in lowered green mussel carrying capacity. This model can assist farm operators with possible management strategies for a sustainable mussel cultivation and protection of the marine environment.

  12. Dependency Modeling of a SOA Based System Through Colored Petri Nets

    Directory of Open Access Journals (Sweden)

    Pawan Kumar

    2016-09-01

    Full Text Available Dependency relationships play an important role in testing, maintenance and configuration management of software systems. The informal dependency representations fail to observe behavioral connections among subsystems and cause ambiguity in representing different types of dependency relationships. Therefore, dependency in a software system requires a formal and unambiguous representation so that its correct effects can be visualized. In this paper, we present a Colored Petri Net based dependency analysis of a Service Oriented Architecture (SOA based system that represents specification of dependency relationships and models the dependencies in a SOA based system at conceptual level. Different types of dependency relations are represented in a formal manner by using Service Algebra. A module SOA based system ‘Online Bookshop’ has been developed and used for the purpose of modeling and example demonstration. Such modeling can help in identification of inconsistency among services, and web services can be verified for safety and reliability.

  13. Modelling and analysis of the feeding regimen induced entrainment of hepatocyte circadian oscillators using petri nets.

    Directory of Open Access Journals (Sweden)

    Samar Hayat Khan Tareen

    Full Text Available Circadian rhythms are certain periodic behaviours exhibited by living organism at different levels, including cellular and system-wide scales. Recent studies have found that the circadian rhythms of several peripheral organs in mammals, such as the liver, are able to entrain their clocks to received signals independent of other system level clocks, in particular when responding to signals generated during feeding. These studies have found SIRT1, PARP1, and HSF1 proteins to be the major influencers of the core CLOCKBMAL1:PER-CRY circadian clock. These entities, along with abstracted feeding induced signals were modelled collectively in this study using Petri Nets. The properties of the model show that the circadian system itself is strongly robust, and is able to continually evolve. The modelled feeding regimens suggest that the usual 3 meals/day and 2 meals/day feeding regimens are beneficial with any more or less meals/day negatively affecting the system.

  14. Modelling and analysis of the feeding regimen induced entrainment of hepatocyte circadian oscillators using petri nets.

    Science.gov (United States)

    Tareen, Samar Hayat Khan; Ahmad, Jamil

    2015-01-01

    Circadian rhythms are certain periodic behaviours exhibited by living organism at different levels, including cellular and system-wide scales. Recent studies have found that the circadian rhythms of several peripheral organs in mammals, such as the liver, are able to entrain their clocks to received signals independent of other system level clocks, in particular when responding to signals generated during feeding. These studies have found SIRT1, PARP1, and HSF1 proteins to be the major influencers of the core CLOCKBMAL1:PER-CRY circadian clock. These entities, along with abstracted feeding induced signals were modelled collectively in this study using Petri Nets. The properties of the model show that the circadian system itself is strongly robust, and is able to continually evolve. The modelled feeding regimens suggest that the usual 3 meals/day and 2 meals/day feeding regimens are beneficial with any more or less meals/day negatively affecting the system.

  15. Petri Nets Based Modelling of Control Flow for Memory-Aid Interactive Programs in Telemedicine

    CERN Document Server

    Khoromskaia, V K

    2004-01-01

    Petri Nets (PN) based modelling of the control flow for the interactive memory assistance programs designed for personal pocket computers and having special requirements for robustness is considered. The proposed concept allows one to elaborate the programs which can give users a variety of possibilities for a day-time planning in the presence of environmental and time restrictions. First, a PN model for a known simple algorithm is constructed and analyzed using the corresponding state equations and incidence matrix. Then a PN graph for a complicated algorithm with overlapping actions and choice possibilities is designed, supplemented by an example of its analysis. Dynamic behaviour of this graph is tested by tracing of all possible paths of the flow of control using the PN simulator. It is shown that PN based modelling provides reliably predictable performance of interactive algorithms with branched structures and concurrency requirements.

  16. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111167 Cao Zhonghuang(Wuhan Iron & Steel Group Minerals Company,Wuhan 430063,China);Luo Xianrong Comparative Study of Copper-Nickel Deposit Exploration by the Geoelectro-chemical Extraction Method in Different Overburden Areas(Geology and Prospecting,ISSN0495-5331,CN11-2043/P,46(3),2010,p.476-482,4 illus.,5 tables,20 refs.)Key words:geo-electrochemical methods,copper ores,nickel ores,Gansu Province,Jilin Province The authors have made a comparative study of quantitative and qualitative analysis and application of the geoelectro-chemical extraction method in different overburden areas in southward extension of Jinchuan in Gansu Province and Hongqiling in Jilin Province.The authors found that this method extracted very few ions in arid areas covered with debris,but the prospecting effect was almost the same as that in moist areas covered with thick overburden.And this method could show objectively differences of geochemical characters

  17. Colored petri nets to model gene mutation and amino acids classification.

    Science.gov (United States)

    Yang, Jinliang; Gao, Rui; Meng, Max Q-H; Tarn, Tzyh-Jong

    2012-05-07

    The genetic code is the triplet code based on the three-letter codons, which determines the specific amino acid sequences in proteins synthesis. Choosing an appropriate model for processing these codons is a useful method to study genetic processes in Molecular Biology. As an effective modeling tool of discrete event dynamic systems (DEDS), colored petri net (CPN) has been used for modeling several biological systems, such as metabolic pathways and genetic regulatory networks. According to the genetic code table, CPN is employed to model the process of genetic information transmission. In this paper, we propose a CPN model of amino acids classification, and further present the improved CPN model. Based on the model mentioned above, we give another CPN model to classify the type of gene mutations via contrasting the bases of DNA strands and the codons of amino acids along the polypeptide chain. This model is helpful in determining whether a certain gene mutation will cause the changes of the structures and functions of protein molecules. The effectiveness and accuracy of the presented model are illustrated by the examples in this paper.

  18. Hydrogeological and geochemical modeling of hydrothermal fluids circulation in active ultramafic-hosted systems under CAST3M

    Science.gov (United States)

    Perez, F.; Mugler, C.; Jean-Baptiste, P.; Charlou, J. L.; Donval, J.; Vidal, O.; Marcailloux, C.; Munoz, M.

    2010-12-01

    Hydrothermal circulation at mid-ocean ridges is a fundamental process that impacts the transfer of energy and water from the interior of the Earth to the Crust, Hydrosphere and biosphere. Along the Mid-Atlantic Ridge (MAR), at precisely located ultramafic-hosted systems, important fluxes of heat, hydrogen and Iron are observed (Charlou et al., 2010 AGU Monograph series). It is now demonstrated that high and low-temperature hydrothermal activity and mantle degassing are indicators of ongoing serpentinization process. For a real understanding of this process and to estimate heat and hydrogen fluxes, numerical modeling leant on field data and laboratory experiments can yield results of interest. We thus developed a thermo-hydrogeological numerical model using a Finite Volume method to simulate heat driven fluid flows in geological layers, encoded under CAST3M, and presented here. For homogeneous medias, we successfully obtained exiting fluid temperatures that natural hydrothermal fluids usually reach. Considering laboratory experiments, we coupled, under CAST3M, our thermo-hydrogeological model to a geochemical model of serpentinization reaction. This last model is based on a reaction front velocity model calibrated by laboratory experiments. Primary results are presented here.

  19. APPLICATION OF WATER FLOW AND GEOCHEMICAL MODELS TO SUPPORT THE REMEDIATION OF ACID ROCK DRAINAGE FROM THE URANIUM MINING SITE OF POCOS DE CALDAS, BRAZIL

    Science.gov (United States)

    This paper discusses the use of two numerical models (HYDRUS-2D and STEADQL-v4) for simulating water flow and relevant geochemical processes in one of the waste rock piles of the first uranium mine in Brazil, in order to facilitate the selection of appropriate remediation strategies. The long time s...

  20. Solid-solution partitioning of heavy metals in floodplain soils of the rivers Rhine and Meuse : Field sampling and geochemical modelling

    NARCIS (Netherlands)

    Schröder, T.J.

    2005-01-01

    In this study, the solid-solution partitioning of Cd, Cr, Cu, Ni, Pb, Zn and As in floodplain soils of the Dutch part of the rivers Rhine and Meuse is assessed by combining extensive field sampling with advanced geochemical modelling. The aim of this study was threefold: to develop tools to study th

  1. A modeling approach to compute modification of net joint forces caused by coping movements in obstetric brachial plexus palsy

    OpenAIRE

    2013-01-01

    Background Many disorders of the musculoskeletal system are caused by modified net joint forces resulting from individual coping movement strategies of patients suffering from neuromuscular diseases. Purpose of this work is to introduce a personalized biomechanical model which allows the calculation of individual net joint forces via inverse dynamics based on anthropometry and kinematics of the upper extremity measured by 3D optoelectronical motion analysis. Methods The determined resulting n...

  2. Document Representation and Clustering with WordNet Based Similarity Rough Set Model

    Directory of Open Access Journals (Sweden)

    Koichi Yamada

    2011-09-01

    Full Text Available Most studies on document clustering till date use Vector Space Model (VSM to represent documents in the document space, where documents are denoted by a vector in a word vector space. The standard VSM does not take into account the semantic relatedness between terms. Thus, terms with some semantic similarity are dealt with in the same way as terms with no semantic relatedness. Since this unconcern about semantics reduces the quality of clustering results, many studies have proposed various approaches to introduce knowledge of semantic relatedness into VSM model. Those approaches give better results than the standard VSM. However they still have their own issues. We propose a new approach as a combination of two approaches, one of which uses Rough Sets theory and co-occurrence of terms, and the other uses WordNet knowledge to solve these issues. Experiments for its evaluation show advantage of the proposed approach over the others.

  3. Modelling Net Ecosystem Exchange and LUE in Mediterranean Oak Forest by Satellite Remote Sensing

    Science.gov (United States)

    Tramontana, Gianluca; Papale, Dario

    2011-01-01

    Net Ecosystem Exchange (NEE) is a key factor defining CO2 fluxes between atmosphere and ecosystems and CO2 flux measurements at individual eddy covariance flux sites provide valuable information on the seasonal dynamics of NEE. In this work, we developed and validated a satellite-based Light Use Efficiency (LUE) model to estimate NEE for a typical oak forest located in Central Italy. Satellite data were acquired by Moderate resolution spectroradiometer (MODIS) sensor installed on board Terra satellite. Oak forest studied is coppice managed; 2 eddy-covariance towers are located inside two forests parcels having different ages. We proposed to estimate LUE like function of mean brightness temperature, Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI). Empirical multiple regressions models (MR) and Artificial Neural Network (ANN) were parameterized and validated using subset of data acquired by both the stations. Daily, 8-day and monthly temporal resolutions were investigated and accuracy estimation in space and time was performed.

  4. Discussion of using artificial neural nets to identify the well-test interpretation model

    Energy Technology Data Exchange (ETDEWEB)

    Yeung, K. (Univ. of Alberta, Edmonton, Alberta (Canada)); Chakrabarty, C. (Golder Associates, Nottingham (United Kingdom)); Wu, S. (Univ. of Melbourne (Australia))

    1994-09-01

    Use of artificial neural nets (ANN's) to identify noisy and apparently unrecognizable patterns is common for many real-world problems, ranging from applications such as speech recognition to stock market prediction. ANN approaches are often good candidates for recognizing patterns when rigid mathematical models do not exist or are insufficient to meet a full-scale identification requirement. Al-Kaabi and Lee's proposal of using ANN's to identify the well-test interpretation model is appropriate because well-test data is often highly nonlinear and noisy. The purpose of this discussion is to present some of the authors results in a similar study and to suggest a simple technique that would enhance the use of ANN's in Al-Kaabi and Lee's approach.

  5. Bayesian Inference using Neural Net Likelihood Models for Protein Secondary Structure Prediction

    Directory of Open Access Journals (Sweden)

    Seong-Gon Kim

    2011-06-01

    Full Text Available Several techniques such as Neural Networks, Genetic Algorithms, Decision Trees and other statistical or heuristic methods have been used to approach the complex non-linear task of predicting Alpha-helicies, Beta-sheets and Turns of a proteins secondary structure in the past. This project introduces a new machine learning method by using an offline trained Multilayered Perceptrons (MLP as the likelihood models within a Bayesian Inference framework to predict secondary structures proteins. Varying window sizes are used to extract neighboring amino acid information and passed back and forth between the Neural Net models and the Bayesian Inference process until there is a convergence of the posterior secondary structure probability.

  6. Global net land carbon sink: Results from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP)

    Science.gov (United States)

    Huntzinger, D. N.; Schwalm, C. R.; Michalak, A. M.; Cook, R. B.; Jacobson, A. R.; Schaefer, K. M.; Dasgupta, A.; Poco, J.

    2013-12-01

    The Multi-scale Synthesis and Model Intercomparison Project (MsTMIP) is a formal model intercomparison effort focused on improving the diagnosis and attribution of carbon exchange at regional and global scales. Here we present results from the terrestrial biospheric models participating in the MsTMIP effort, focusing on global and regional model estimates of the net land carbon sink. When compared to estimates of the residual net land sink inferred from atmospheric CO2 observations (i.e., fossil fuel emission + land use land cover change - atmospheric increase - ocean uptake), MsTMIP models predict, on average, a weaker global net land uptake of carbon. There is a large spread in MsTMIP estimates of the net land sink (e.g., -2.5 to 5.0 Pg C/yr in 2010, where a negative flux represents a net release to the atmosphere). Some models consistently show the land surface as a net source of carbon to the atmosphere, which is inconsistent with the atmospheric record. In addition, we examine how model estimates of the cumulative global net sink diverge over the period 1900 to 2010, and the degree to which model sensitivity to forcing factors and fundamental differences in model formulation contribute to this divergence. We link differences in estimates of the cumulative land sink back to each model's sensitivity to key forcing factors including climate variability, CO2 fertilization, nitrogen limitation, and land cover / land-use change. For example, the strength of carbon uptake in most models appears to be strongly coupled with atmospheric CO2 concentrations (CO2 fertilization effect). The strength of this relationship, however, varies across models with some models exhibiting a very strong CO2 fertilization effect (e.g., ORCHIDEE), while others not so (e.g., CLM). To inform the comparison across models, structural differences (i.e., which processes are included and how those processes are parameterized) among the participating models are evaluated using hierarchical

  7. Uncertainty estimation of the velocity model for the TrigNet GPS network

    Science.gov (United States)

    Hackl, Matthias; Malservisi, Rocco; Hugentobler, Urs; Wonnacott, Richard

    2010-05-01

    Satellite based geodetic techniques - above all GPS - provide an outstanding tool to measure crustal motions. They are widely used to derive geodetic velocity models that are applied in geodynamics to determine rotations of tectonic blocks, to localize active geological features, and to estimate rheological properties of the crust and the underlying asthenosphere. However, it is not a trivial task to derive GPS velocities and their uncertainties from positioning time series. In general time series are assumed to be represented by linear models (sometimes offsets, annual, and semi-annual signals are included) and noise. It has been shown that models accounting only for white noise tend to underestimate the uncertainties of rates derived from long time series and that different colored noise components (flicker noise, random walk, etc.) need to be considered. However, a thorough error analysis including power spectra analyses and maximum likelihood estimates is quite demanding and are usually not carried out for every site, but the uncertainties are scaled by latitude dependent factors. Analyses of the South Africa continuous GPS network TrigNet indicate that the scaled uncertainties overestimate the velocity errors. So we applied a method similar to the Allan Variance that is commonly used in the estimation of clock uncertainties and is able to account for time dependent probability density functions (colored noise) to the TrigNet time series. Finally, we compared these estimates to the results obtained by spectral analyses using CATS. Comparisons with synthetic data show that the noise can be represented quite well by a power law model in combination with a seasonal signal in agreement with previous studies.

  8. A novel transferable individual tree crown delineation model based on Fishing Net Dragging and boundary classification

    Science.gov (United States)

    Liu, Tao; Im, Jungho; Quackenbush, Lindi J.

    2015-12-01

    This study provides a novel approach to individual tree crown delineation (ITCD) using airborne Light Detection and Ranging (LiDAR) data in dense natural forests using two main steps: crown boundary refinement based on a proposed Fishing Net Dragging (FiND) method, and segment merging based on boundary classification. FiND starts with approximate tree crown boundaries derived using a traditional watershed method with Gaussian filtering and refines these boundaries using an algorithm that mimics how a fisherman drags a fishing net. Random forest machine learning is then used to classify boundary segments into two classes: boundaries between trees and boundaries between branches that belong to a single tree. Three groups of LiDAR-derived features-two from the pseudo waveform generated along with crown boundaries and one from a canopy height model (CHM)-were used in the classification. The proposed ITCD approach was tested using LiDAR data collected over a mountainous region in the Adirondack Park, NY, USA. Overall accuracy of boundary classification was 82.4%. Features derived from the CHM were generally more important in the classification than the features extracted from the pseudo waveform. A comprehensive accuracy assessment scheme for ITCD was also introduced by considering both area of crown overlap and crown centroids. Accuracy assessment using this new scheme shows the proposed ITCD achieved 74% and 78% as overall accuracy, respectively, for deciduous and mixed forest.

  9. The case for NetCDF as a groundwater model output format using R: Example using USGS MODFLOW

    Science.gov (United States)

    Coulibaly, K. M.; Barnes, M.; Barnes, D.

    2011-12-01

    The USGS MODFLOW code has become the most widely used groundwater flow code throughout the world since its release in 1989. Because MODFLOW is a plain FORTRAN code with no graphical user interface (GUI) or visualization capabilities, model results visualization and analysis is usually done with commercial or open-source packages, and self-made FORTRAN snippets. The output format of MODFLOW is a FORTRAN binary which may vary depending on compilers and platforms. NetCDF, on the other hand, is a standardized, sharable and compact format which can be read and visualized with numerous free and commercial packages including R. It is also possible to embed useful geospatial information like coordinates, projection and grid discretization in the NetCDF which are absent in the FORTRAN binary. Using NetCDF as a standard model output format would allow modelers and non-modelers to easily share, visualize and plot model results using readily available software (R, ArcGIS, MS Excel, Paraview, GRASS GIS, SAGA GIS...etc). NetCDF is a particularly good format for storing large, multidimensional datasets. Many NetCDF tools were designed for the climate community, whose datasets are often orders of magnitude larger than datasets typically used in groundwater modeling. In this study R was used to generate a NetCDF file from a MODFLOW binary output and example analyses and visualizations were implemented. R has extensive statistical and plotting capabilities which are available to the user once MODFLOW outputs are available in NetCDF format.

  10. EcoCasting: Using NetLogo models of aquatic ecosystems to teach scientific inquiry

    Science.gov (United States)

    Buzby, C. K.; Jona, K.

    2010-12-01

    The EcoCasting project from the Office of STEM Education Partnerships (OSEP) at Northwestern University has developed a computer model-based curriculum for high school environmental science classes to study complexity in aquatic ecosystems. EcoCasting aims to deliver cutting edge scientific research on bioaccumulation in invaded Great Lakes food webs to high school classes. Scientists and environmental engineers at Northwestern are investigating unusual bioaccumulation patterns in invaded food webs of the Great Lakes. High school students are exploring this authentic data to understand what is causing the anomalies in the data. Students use a series of NetLogo agent-based models of an aquatic ecosystem to study how toxins accumulate in the food web. Using these models, students learn about predator-prey relationships, bioaccumulation, and invasive species. Students are confronted with contradictory data collected by scientists and investigate alternative food web mechanisms at work. By studying the individual variables, students learn common scientific principles. When multiple variables are combined in a unifying model, students learn that the interactions lead to unexpected outcomes. Students learn about the complexity of the ecosystem and gain proficiency interpreting computer models and scientific data collection in this curriculum. Model of aquatic food chain

  11. Modelling of long term geochemical evolution and study of mechanical perturbation of bentonite buffer of a KBS-3 repository

    Energy Technology Data Exchange (ETDEWEB)

    Marsal, Francois; Pellegrini, Delphine; Deleruyelle, Frederic; Serres, Christophe (French Institute for Radiological Protection and Nuclear Safety (IRSN) (FR)); Windt, Laurent de (Paris School of Mines (ENSMP) (FR))

    2008-03-15

    The Swedish Nuclear Fuel and Waste Management Co. (SKB) has recently completed a safety assessment project named SR-Can, related to the KBS-3 disposal concept. In this concept, the waste packages are surrounded by a buffer made of either MX-80 or Deponit CA-N bentonite. Interactions between the buffer and groundwater may modify the buffer composition and thus its containment properties. The Swedish Radiation Protection Authorities (SSI) requested the French Institute for Radiological Protection and Nuclear Safety (IRSN) to perform the present study in support of SSI review of the SR-Can report. The purpose is to assess the geochemical evolution of both potential buffer materials due to the intrusion of different types of groundwater, with a similar modelling layout to that reported in SR-Can. Three main categories of water inflows via a fracture intersecting a deposition hole are considered: the Forsmark reference groundwater, a high-salinity groundwater to account for up-rise of deep-seated brines and a diluted water representing ice-melting derived groundwater. In addition to this, the redox buffering capacity of Deponit CA-N bentonite and the thermal effect on MX-80 bentonite geochemistry have been assessed. This modelling work has been performed using the reactive transport modelling code HYTEC. The main outcome of the present study is that the intrusion of the considered groundwaters should not affect drastically the geochemistry of neither the Deponit CA-N nor the MX-80 bentonite on the long-term (100,000 y). Bentonite pH may reach high values (up to 10.5) in some cases but does not reach SKB criterion value related to bentonite chemical stability. Dissolution-precipitation of accessory minerals is not significant enough to induce important porosity changes (rise by maximum 2 %). Globally, the montmorillonite exchanger undergoes Na by Ca partial replacement, which may decrease the swelling pressure of the bentonite. The simulated intrusion of oxidizing waters

  12. Solid phase evolution in the Biosphere 2 hillslope experiment as predicted by modeling of hydrologic and geochemical fluxes

    Directory of Open Access Journals (Sweden)

    K. Dontsova

    2009-12-01

    Full Text Available A reactive transport geochemical modeling study was conducted to help predict the mineral transformations occurring over a ten year time-scale that are expected to impact soil hydraulic properties in the Biosphere 2 (B2 synthetic hillslope experiment. The modeling sought to predict the rate and extent of weathering of a granular basalt (selected for hillslope construction as a function of climatic drivers, and to assess the feedback effects of such weathering processes on the hydraulic properties of the hillslope. Flow vectors were imported from HYDRUS into a reactive transport code, CrunchFlow2007, which was then used to model mineral weathering coupled to reactive solute transport. Associated particle size evolution was translated into changes in saturated hydraulic conductivity using Rosetta software. We found that flow characteristics, including velocity and saturation, strongly influenced the predicted extent of incongruent mineral weathering and neo-phase precipitation on the hillslope. Results were also highly sensitive to specific surface areas of the soil media, consistent with surface reaction controls on dissolution. Effects of fluid flow on weathering resulted in significant differences in the prediction of soil particle size distributions, which should feedback to alter hillslope hydraulic conductivities.

  13. Coupled modeling of hydrologic and geochemical fluxes for prediction of solid phase evolution in the Biosphere 2 hillslope experiment

    Science.gov (United States)

    Dontsova, K.; Steefel, C. I.; Desilets, S.; Thompson, A.; Chorover, J.

    2009-06-01

    A reactive transport geochemical modeling study was conducted to help predict the mineral transformations occurring over a ten year time-scale that are expected to impact soil hydraulic properties in the Biosphere 2 (B2) synthetic hillslope experiment. The modeling sought to predict the rate and extent of weathering of a granular basalt (selected for hillslope construction) as a function of climatic drivers, and to assess the feedback effects of such weathering processes on the hydraulic properties of the hillslope. Flow vectors were imported from HYDRUS into a reactive transport code, CrunchFlow2007, which was then used to model mineral weathering coupled to reactive solute transport. Associated particle size evolution was translated into changes in saturated hydraulic conductivity using Rosetta software. We found that flow characteristics, including velocity and saturation, strongly influenced the predicted extent of incongruent mineral weathering and neo-phase precipitation on the hillslope. Results were also highly sensitive to specific surface areas of the soil media, consistent with surface reaction controls on dissolution. Effects of fluid flow on weathering resulted in significant differences in the prediction of soil particle size distributions, which should feedback to alter hillslope hydraulic conductivities.

  14. Solid phase evolution in the Biosphere 2 hillslope experiment as predicted by modeling of hydrologic and geochemical fluxes

    Science.gov (United States)

    Dontsova, K.; Steefel, C. I.; Desilets, S.; Thompson, A.; Chorover, J.

    2009-12-01

    A reactive transport geochemical modeling study was conducted to help predict the mineral transformations occurring over a ten year time-scale that are expected to impact soil hydraulic properties in the Biosphere 2 (B2) synthetic hillslope experiment. The modeling sought to predict the rate and extent of weathering of a granular basalt (selected for hillslope construction) as a function of climatic drivers, and to assess the feedback effects of such weathering processes on the hydraulic properties of the hillslope. Flow vectors were imported from HYDRUS into a reactive transport code, CrunchFlow2007, which was then used to model mineral weathering coupled to reactive solute transport. Associated particle size evolution was translated into changes in saturated hydraulic conductivity using Rosetta software. We found that flow characteristics, including velocity and saturation, strongly influenced the predicted extent of incongruent mineral weathering and neo-phase precipitation on the hillslope. Results were also highly sensitive to specific surface areas of the soil media, consistent with surface reaction controls on dissolution. Effects of fluid flow on weathering resulted in significant differences in the prediction of soil particle size distributions, which should feedback to alter hillslope hydraulic conductivities.

  15. Solid phase evolution in the Biosphere 2 hillslope experiment as predicted by modeling of hydrologic and geochemical fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Dontsova, K.; Steefel, C.I.; Desilets, S.; Thompson, A.; Chorover, J.

    2009-07-15

    A reactive transport geochemical modeling study was conducted to help predict the mineral transformations occurring over a ten year time-scale that are expected to impact soil hydraulic properties in the Biosphere 2 (B2) synthetic hillslope experiment. The modeling sought to predict the rate and extent of weathering of a granular basalt (selected for hillslope construction) as a function of climatic drivers, and to assess the feedback effects of such weathering processes on the hydraulic properties of the hillslope. Flow vectors were imported from HYDRUS into a reactive transport code, CrunchFlow2007, which was then used to model mineral weathering coupled to reactive solute transport. Associated particle size evolution was translated into changes in saturated hydraulic conductivity using Rosetta software. We found that flow characteristics, including velocity and saturation, strongly influenced the predicted extent of incongruent mineral weathering and neo-phase precipitation on the hillslope. Results were also highly sensitive to specific surface areas of the soil media, consistent with surface reaction controls on dissolution. Effects of fluid flow on weathering resulted in significant differences in the prediction of soil particle size distributions, which should feedback to alter hillslope hydraulic conductivities.

  16. Centrality dependence of chemical freeze-out parameters from net-proton and net-charge fluctuations using hadron resonance gas model

    CERN Document Server

    Adak, Rama Prasad; Ghosh, Sanjay K; Ray, Rajarshi; Samanta, Subhasis

    2016-01-01

    We extract chemical freeze-out parameters in HRG and EVHRG model, analysing the experimental information of net-proton and net-charge fluctuations measured in Au + Au collisions by the STAR collaboration at RHIC. We observe that chemical freeze-out parameters extracted from lower and higher order fluctuations are though almost same for $\\sqrt{s_{NN}} > 27$ GeV, they tend to deviate from each other at lower $\\sqrt{s_{NN}}$. Moreover, these separations increase with decrease of $\\sqrt{s_{NN}}$ and for a fixed $\\sqrt{s_{NN}}$ increase towards central collisions. This may be an indication of approach of critical region at lower $\\sqrt{s_{NN}}$. Furthermore, we observe an approximate scaling behaviour of $(\\mu_B/T)/(\\mu_B/T)_{central}$ with $(N_{part})/(N_{part})_{central}$ for the parameters extracted from lower order fluctuations for 11.5 GeV $\\le \\sqrt{s_{NN}} \\le$ 200 GeV. Scaling is violated for the parameters extracted from higher order fluctuations for $\\sqrt{s_{NN}}= 11.5$ and 19.6 GeV. It is observed that...

  17. Accelerometer signal-based human activity recognition using augmented autoregressive model coefficients and artificial neural nets.

    Science.gov (United States)

    Khan, A M; Lee, Y K; Kim, T S

    2008-01-01

    Automatic recognition of human activities is one of the important and challenging research areas in proactive and ubiquitous computing. In this work, we present some preliminary results of recognizing human activities using augmented features extracted from the activity signals measured using a single triaxial accelerometer sensor and artificial neural nets. The features include autoregressive (AR) modeling coefficients of activity signals, signal magnitude areas (SMA), and title angles (TA). We have recognized four human activities using AR coefficients (ARC) only, ARC with SMA, and ARC with SMA and TA. With the last augmented features, we have achieved the recognition rate above 99% for all four activities including lying, standing, walking, and running. With our proposed technique, real time recognition of some human activities is possible.

  18. The use of the Petri net method in the simulation modeling of mitochondrial swelling

    Directory of Open Access Journals (Sweden)

    Yu. V. Danylovych

    2016-08-01

    Full Text Available Using photon correlation spectroscopy, which allows investigating changes in the hydrodynamic dia­meter of the particles in suspension, it was shown that ultrahigh concentrations of Ca2+ (over 10 mM induce swelling of isolated mitochondria. An increase in hydrodynamic diameter was caused by an increase of non-specific mitochondrial membrane permeability to Ca ions, matrix Ca2+ overload, activation of ATP- and Ca2+-sensitive K+-channels, as well as activation of cyclosporin-sensitive permeability transition pore. To formalize the experimental data and to assess conformity of experimental results with theoretical predictions we developed a simulation model using the hybrid functional Petri net method.

  19. c060: Extended Inference with Lasso and Elastic-Net Regularized Cox and Generalized Linear Models

    Directory of Open Access Journals (Sweden)

    Martin Sill

    2014-12-01

    Full Text Available We have developed the R package c060 with the aim of improving R software func- tionality for high-dimensional risk prediction modeling, e.g., for prognostic modeling of survival data using high-throughput genomic data. Penalized regression models provide a statistically appealing way of building risk prediction models from high-dimensional data. The popular CRAN package glmnet implements an efficient algorithm for fitting penalized Cox and generalized linear models. However, in practical applications the data analysis will typically not stop at the point where the model has been fitted. One is for example often interested in the stability of selected features and in assessing the prediction performance of a model and we provide functions to deal with both of these tasks. Our R functions are computationally efficient and offer the possibility of speeding up computing time through parallel computing. Another feature which can drastically reduce computing time is an efficient interval-search algorithm, which we have implemented for selecting the optimal parameter combination for elastic net penalties. These functions have been useful in our daily work at the Biostatistics department (C060 of the German Cancer Research Center where prognostic modeling of patient survival data is of particular interest. Although we focus on a survival data application of penalized Cox models in this article, the functions in our R package are in general applicable to all types of regression models implemented in the glmnet package, with the exception of prediction error curves, which are specific to time-to-event data.

  20. A kinetic model for estimating net photosynthetic rates of cos lettuce leaves under pulsed light.

    Science.gov (United States)

    Jishi, Tomohiro; Matsuda, Ryo; Fujiwara, Kazuhiro

    2015-04-01

    Time-averaged net photosynthetic rate (P n) under pulsed light (PL) is known to be affected by the PL frequency and duty ratio, even though the time-averaged photosynthetic photon flux density (PPFD) is unchanged. This phenomenon can be explained by considering that photosynthetic intermediates (PIs) are pooled during light periods and then consumed by partial photosynthetic reactions during dark periods. In this study, we developed a kinetic model to estimate P n of cos lettuce (Lactuca sativa L. var. longifolia) leaves under PL based on the dynamics of the amount of pooled PIs. The model inputs are average PPFD, duty ratio, and frequency; the output is P n. The rates of both PI accumulation and consumption at a given moment are assumed to be dependent on the amount of pooled PIs at that point. Required model parameters and three explanatory variables (average PPFD, frequency, and duty ratio) were determined for the simulation using P n values under PL based on several combinations of the three variables. The model simulation for various PL levels with a wide range of time-averaged PPFDs, frequencies, and duty ratios further demonstrated that P n under PL with high frequencies and duty ratios was comparable to, but did not exceed, P n under continuous light, and also showed that P n under PL decreased as either frequency or duty ratio was decreased. The developed model can be used to estimate P n under various light environments where PPFD changes cyclically.

  1. Reactive transport modeling of geochemical controls on secondary water quality impacts at a crude oil spill site near Bemidji, MN

    Science.gov (United States)

    Ng, Gene-Hua Crystal.; Bekins, Barbara A.; Cozzarelli, Isabelle M.; Baedecker, Mary Jo; Bennett, Philip C.; Amos, Richard T.; Herkelrath, William N.

    2015-01-01

    Anaerobic biodegradation of organic amendments and contaminants in aquifers can trigger secondary water quality impacts that impair groundwater resources. Reactive transport models help elucidate how diverse geochemical reactions control the spatiotemporal evolution of these impacts. Using extensive monitoring data from a crude oil spill site near Bemidji, Minnesota (USA), we implemented a comprehensive model that simulates secondary plumes of depleted dissolved O2 and elevated concentrations of Mn2+, Fe2+, CH4, and Ca2+ over a two-dimensional cross section for 30 years following the spill. The model produces observed changes by representing multiple oil constituents and coupled carbonate and hydroxide chemistry. The model includes reactions with carbonates and Fe and Mn mineral phases, outgassing of CH4 and CO2 gas phases, and sorption of Fe, Mn, and H+. Model results demonstrate that most of the carbon loss from the oil (70%) occurs through direct outgassing from the oil source zone, greatly limiting the amount of CH4 cycled down-gradient. The vast majority of reduced Fe is strongly attenuated on sediments, with most (91%) in the sorbed form in the model. Ferrous carbonates constitute a small fraction of the reduced Fe in simulations, but may be important for furthering the reduction of ferric oxides. The combined effect of concomitant redox reactions, sorption, and dissolved CO2 inputs from source-zone degradation successfully reproduced observed pH. The model demonstrates that secondary water quality impacts may depend strongly on organic carbon properties, and impacts may decrease due to sorption and direct outgassing from the source zone.

  2. Fate of inorganic contaminants post treatment of acid mine drainage by cryptocrystalline magnesite: Complimenting experimental results with a geochemical model

    CSIR Research Space (South Africa)

    Masindi, V

    2016-03-01

    Full Text Available This study assessed the fate of inorganic contaminants post treatment of acid mine drainage by cryptocrystalline magnesite. To accomplish that, neutralization and metal attenuation were evaluated and complemented with simulations using geochemical...

  3. Estimation of net primary productivity using a process-based model in Gansu Province, Northwest China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peijuan; Xie, Donghui; Zhou, Yuyu; E, Youhao; Zhu, Qijiang

    2014-01-16

    The ecological structure in the arid and semi-arid region of Northwest China with forest, grassland, agriculture, Gobi, and desert, is complex, vulnerable, and unstable. It is a challenging and sustaining job to keep the ecological structure and improve its ecological function. Net primary productivity (NPP) modeling can help to improve the understanding of the ecosystem, and therefore, improve ecological efficiency. The boreal ecosystem productivity simulator (BEPS) model provides the possibility of NPP modeling in terrestrial ecosystem, but it has some limitations for application in arid and semi-arid regions. In this paper we improve the BEPS model, in terms of its water cycle by adding the processes of infiltration and surface runoff, to be applicable in arid and semi-arid regions. We model the NPP of forest, grass, and crop in Gansu Province as an experimental area in Northwest China in 2003 using the improved BEPS model, parameterized with moderate resolution remote sensing imageries and meteorological data. The modeled NPP using improved BEPS agrees better with the ground measurements in Qilian Mountain than that with original BEPS, with a higher R2 of 0.746 and lower root mean square error (RMSE) of 46.53 gC/m2 compared to R2 of 0.662 and RMSE of 60.19 gC/m2 from original BEPS. The modeled NPP of three vegetation types using improved BEPS show evident differences compared to that using original BEPS, with the highest difference ratio of 9.21% in forest and the lowest value of 4.29% in crop. The difference ratios between different vegetation types lie on the dependence on natural water sources. The modeled NPP in five geographic zones using improved BEPS are higher than those with original BEPS, with higher difference ratio in dry zones and lower value in wet zones.

  4. Study of the leaching behaviour of ladle slags by means of leaching tests combined with geochemical modelling and mineralogical investigations.

    Science.gov (United States)

    Loncnar, Mojca; van der Sloot, Hans A; Mladenovič, Ana; Zupančič, Marija; Kobal, Lara; Bukovec, Peter

    2016-11-05

    In this study, the leachability of freshly produced ladle slag derived from both austenitic and ferritic stainless steel production, and from electrical and structural steel production, was investigated, in order to determine whether variations in the chemical and mineralogical composition of these slags affect their leaching behaviour. The effect of the method used for slag cooling was also studied. The results obtained by using the single batch test were combined with those obtained by means of more sophisticated characterisation leaching tests, which, in combination with geochemical speciation modelling, helped to better identify the release mechanisms and phases that control the release of individual elements. It was found that, although variations in the chemical composition of the slag can affect the slag's minerology, neither such variations, nor the choice of the slag cooling treatment, have a significant effect on the leachability of individual elements, since the leaching is governed by surface phenomena. In fact, the mineral transformations on the slag surface, rather than the bulk mineral composition, dictate the release of these elements from the ladle slag. The solubility-controlling phases were predicted by multi-element modelling, and verified to the extent made possible by the performed mineralogical investigations.

  5. Pan-Arctic modelling of net ecosystem exchange of CO2.

    Science.gov (United States)

    Shaver, G R; Rastetter, E B; Salmon, V; Street, L E; van de Weg, M J; Rocha, A; van Wijk, M T; Williams, M

    2013-08-19

    Net ecosystem exchange (NEE) of C varies greatly among Arctic ecosystems. Here, we show that approximately 75 per cent of this variation can be accounted for in a single regression model that predicts NEE as a function of leaf area index (LAI), air temperature and photosynthetically active radiation (PAR). The model was developed in concert with a survey of the light response of NEE in Arctic and subarctic tundras in Alaska, Greenland, Svalbard and Sweden. Model parametrizations based on data collected in one part of the Arctic can be used to predict NEE in other parts of the Arctic with accuracy similar to that of predictions based on data collected in the same site where NEE is predicted. The principal requirement for the dataset is that it should contain a sufficiently wide range of measurements of NEE at both high and low values of LAI, air temperature and PAR, to properly constrain the estimates of model parameters. Canopy N content can also be substituted for leaf area in predicting NEE, with equal or greater accuracy, but substitution of soil temperature for air temperature does not improve predictions. Overall, the results suggest a remarkable convergence in regulation of NEE in diverse ecosystem types throughout the Arctic.

  6. Contribution of aboveground biomass uncertainty to bias in modeled global net ecosystem exchange

    Science.gov (United States)

    Poulter, B.; Delbart, N.; Maignan, F.; Saatchi, S. S.; Sitch, S.; Ciais, P.

    2011-12-01

    Biomass is a key ecosystem property that links biogeochemical fluxes with the accumulation of carbon. The spatial and temporal dynamics of biomass have implications for climate stability and other ecosystem services. Globally, terrestrial forest ecosystems store approximately 383 Pg C in aboveground biomass, about 45% compared to the amount of carbon in the atmosphere. Model-data comparisons of aboveground biomass have so far been limited by a lack of wall-to-wall coverage, which has recently been resolved from satellite remote sensing. These recent satellite products use lidar to measure forest structure directly or have developed novel data-fusion techniques. Here, we compare biomass estimates among terrestrial carbon cycle models, and benchmark these estimates with inventory and satellite-based estimates. Using an ensemble of dynamic global vegetation model simulations from the TRENDY archive, we then use the distribution of biomass estimates to evaluate bias in net ecosystem exchange caused by uncertainty from carbon turnover. By identifying detailed model structure and parameters that are linked to carbon turnover, targeted improvements can be made to more realistically simulate aboveground biomass.

  7. A Comprehensive Availability Modeling and Analysis of a Virtualized Servers System Using Stochastic Reward Nets

    Directory of Open Access Journals (Sweden)

    Tuan Anh Nguyen

    2014-01-01

    Full Text Available It is important to assess availability of virtualized systems in IT business infrastructures. Previous work on availability modeling and analysis of the virtualized systems used a simplified configuration and assumption in which only one virtual machine (VM runs on a virtual machine monitor (VMM hosted on a physical server. In this paper, we show a comprehensive availability model using stochastic reward nets (SRN. The model takes into account (i the detailed failures and recovery behaviors of multiple VMs, (ii various other failure modes and corresponding recovery behaviors (e.g., hardware faults, failure and recovery due to Mandelbugs and aging-related bugs, and (iii dependency between different subcomponents (e.g., between physical host failure and VMM, etc. in a virtualized servers system. We also show numerical analysis on steady state availability, downtime in hours per year, transaction loss, and sensitivity analysis. This model provides a new finding on how to increase system availability by combining both software rejuvenations at VM and VMM in a wise manner.

  8. MODELING MULTI-TRAFFIC ADMISSION CONTROL IN OFDMA SYSTEM USING COLORED PETRI NET

    Institute of Scientific and Technical Information of China (English)

    Yao Yuanyuan; Lu Yanhui; Yang Shouyi

    2012-01-01

    Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks.In this paper,we develop an executable top-down hierarchical Colored Petri Net (CPN) model for multi-traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system.By theoretic analysis and CPN simulation,it is demonstrated that the CPN model is isomorphic to Markov Chain (MC) assuming that each data stream follows Poisson distribution and the corresponding arrival time interval is an exponential random variable,and it breaks through MC's explicit limitation,which includes MC's memoryless property and proneness to state space explosion in evaluating CAC process.Moreover,we present four CAC schemes based on CPN model taking into account call-level and packet-level Quality of Service (QoS).The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performance with less computational complexity in addition to its flexibility and adaptability to different scenarios.

  9. A modeling approach to compute modification of net joint forces caused by coping movements in obstetric brachial plexus palsy

    Science.gov (United States)

    2013-01-01

    Background Many disorders of the musculoskeletal system are caused by modified net joint forces resulting from individual coping movement strategies of patients suffering from neuromuscular diseases. Purpose of this work is to introduce a personalized biomechanical model which allows the calculation of individual net joint forces via inverse dynamics based on anthropometry and kinematics of the upper extremity measured by 3D optoelectronical motion analysis. Methods The determined resulting net joint forces in the anatomical axis of movement may be used to explain the reason for possible malfunction of the musculoskeletal system, especially joint malformation. For example the resulting net joint forces in the humerothoracic joint from simulations are compared to a sample of children presenting obstetric brachial plexus palsy showing an internal shoulder rotation position and a sample of healthy children. Results The results presented from the simulation show that an increased internal shoulder rotation position leads to increased net joint forces in the humerothoracic joint. A similar behavior is presented for the subjects suffering from brachial plexus palsy with an internal shoulder rotation position. Conclusions The increased net joint forces are a possible reason for joint malformation in the humerothoracic joint caused by coping movements resulting from neuromuscular dysfunction as stated in literature. PMID:24139445

  10. Australian net (1950s–1990 soil organic carbon erosion: implications for CO2 emission and land–atmosphere modelling

    Directory of Open Access Journals (Sweden)

    A. Chappell

    2014-05-01

    Full Text Available The debate about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2 remains unresolved. There is little historical land use and management context to this debate which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally-induced soil erosion. We use "catchment" scale (∼25 km2 estimates of 137Cs-derived net (1950s–1990 soil redistribution of all processes (wind, water and tillage to calculate the net soil organic carbon (SOC redistribution across Australia. We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s–1990 SOC redistribtion across Australia and estimate erosion by all processes ∼4 Tg SOC yr−1 which represents a~loss of ∼2% of the total carbon stock (0–10 cm of Australia. Assuming this net SOC loss is mineralised, the flux (∼15 Tg CO2-e yr−1 represents an omitted 12% of CO2-e emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes and its omission from land surface models likely creates more uncertainty than has been previously recognised.

  11. Australian net (1950s-1990) soil organic carbon erosion: implications for CO2 emission and land-atmosphere modelling

    Science.gov (United States)

    Chappell, A.; Webb, N. P.; Viscarra Rossel, R. A.; Bui, E.

    2014-09-01

    The debate remains unresolved about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2. There is little historical land use and management context to this debate, which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally-induced soil erosion. We use "catchment" scale (∼25 km2) estimates of 137Cs-derived net (1950s-1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia. We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s-1990) SOC redistribution across Australia and estimate erosion by all processes to be ∼4 Tg SOC yr-1, which represents a loss of ∼2% of the total carbon stock (0-10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (∼15 Tg CO2-equivalents yr-1) represents an omitted 12% of CO2-equivalent emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes, and its omission from land surface models likely creates more uncertainty than has been previously recognised.

  12. Annotating Coloured Petri Nets

    DEFF Research Database (Denmark)

    Lindstrøm, Bo; Wells, Lisa Marie

    2002-01-01

    Coloured Petri nets (CP-nets) can be used for several fundamentally different purposes like functional analysis, performance analysis, and visualisation. To be able to use the corresponding tool extensions and libraries it is sometimes necessary to include extra auxiliary information in the CP-ne...... a certain use of the CP-net. We define the semantics of annotations by describing a translation from a CP-net and the corresponding annotation layers to another CP-net where the annotations are an integrated part of the CP-net....... a method which makes it possible to associate auxiliary information, called annotations, with tokens without modifying the colour sets of the CP-net. Annotations are pieces of information that are not essential for determining the behaviour of the system being modelled, but are rather added to support...

  13. HLW glass dissolution in the presence of magnesium carbonate: Diffusion cell experiment and coupled modeling of diffusion and geochemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Debure, Mathieu, E-mail: mathieu.debure@gmail.com [CEA Marcoule, DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Cèze Cedex (France); Geosciences Dept., Mines-ParisTech, 35 Rue St-Honoré, 77305 Fontainebleau (France); De Windt, Laurent [Geosciences Dept., Mines-ParisTech, 35 Rue St-Honoré, 77305 Fontainebleau (France); Frugier, Pierre; Gin, Stéphane [CEA Marcoule, DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Cèze Cedex (France)

    2013-11-15

    Highlights: •Diffusion of dissolved elements in pore water impacts nuclear glass alteration. •The glass/magnesium carbonate system has been studied in diffusion cells. •Glass alteration is enhanced by Mg–silicates precipitation but slowed down by diffusion. •Coupling between dissolution, diffusion and secondary phases controls the glass alteration. •The ability of reactive transport models to simulate the whole processes is investigated. -- Abstract: The influence of diffusion of reactive species in aqueous solutions on the alteration rate of borosilicate glass of nuclear interest in the presence of magnesium carbonate (hydromagnesite: 4MgCO{sub 3}·Mg(OH){sub 2}·4H{sub 2}O) is investigated together with the ability of coupled chemistry/transport models to simulate the processes involved. Diffusion cells in which the solids are separated by an inert stainless steel sintered filter were used to establish parameters for direct comparison with batch experiments in which solids are intimately mixed. The chemistry of the solution and solid phases was monitored over time by various analytical techniques including ICP-AES, XRD, and SEM. The primary mechanism controlling the geochemical evolution of the system remains the consumption of silicon from the glass by precipitation of magnesium silicates. The solution chemistry and the dissolution and precipitation of solid phases are correctly described by 2D modeling with the GRAAL model implemented in the HYTEC reactive transport code. The spatial symmetry of the boron concentrations in both compartments of the cells results from dissolution coupled with simple diffusion, whereas the spatial asymmetry of the silicon and magnesium concentrations is due to strong coupling between dissolution, diffusion, and precipitation of secondary phases. A sensitivity analysis on the modeling of glass alteration shows that the choice of these phases and their thermodynamic constants have only a moderate impact whereas the

  14. National Geochemical Database: Soil

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of soil samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US...

  15. National Geochemical Database: Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment in...

  16. National Geochemical Database: Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment...

  17. Geochemical modelling study on the age and evolution of the groundwater at the Romuvaara site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Vuorinen, U.; Leino-Forsman, H. [Technical Research Centre of Finland, Espoo (Finland); Snellman, M. [Imatran Voima Oy, Helsinki (Finland)

    1996-09-01

    The objective of the study was to interpret the processes and factors which control the hydrogeochemistry (e.g. pH and redox conditions) in the radioactive waste disposal environment. A model of the hydrogeochemical evolution and the chemical flowpaths in different parts of the bedrock at the Romuvaara (in Finland) site has been created. The significance of chemical reactions along different flowpaths is calculated. Furthermore, the consistency of the hydrogeochemical model and the hydrogeological model is examined. (107 refs.).

  18. Model checking of time Petri nets using the state class timed automaton

    DEFF Research Database (Denmark)

    Lime, Didier; Roux, Olivier H.

    2006-01-01

    In this paper, we propose a method for building the state class graph of a bounded time Petri net (TPN) as a timed automaton (TA), which we call the state class timed automaton. We consider bounded TPN, whose underlying net is not necessarily bounded. We prove that our translation preserves...

  19. Assessment of co-contaminant effects on uranium and thorium speciation in freshwater using geochemical modelling.

    Science.gov (United States)

    Lofts, Stephen; Fevrier, Laureline; Horemans, Nele; Gilbin, Rodolphe; Bruggeman, Christophe; Vandenhove, Hildegarde

    2015-11-01

    Speciation modelling of uranium (as uranyl) and thorium, in four freshwaters impacted by mining activities, was used to evaluate (i) the influence of the co-contaminants present on the predicted speciation, and (ii) the influence of using nine different model/database combinations on the predictions. Generally, co-contaminants were found to have no significant effects on speciation, with the exception of Fe(III) in one system, where formation of hydrous ferric oxide and adsorption of uranyl to its surface impacted the predicted speciation. Model and database choice on the other hand clearly influenced speciation prediction. Complexes with dissolved organic matter, which could be simulated by three of the nine model/database combinations, were predicted to be important in a slightly acidic, soft water. Model prediction of uranyl and thorium speciation needs to take account of database comprehensiveness and cohesiveness, including the capability of the model and database to simulate interactions with dissolved organic matter. Measurement of speciation in natural waters is needed to provide data that may be used to assess and improve model capabilities and to better constrain the type of predictive modelling work presented here.

  20. Lattice Boltzmann based multicomponent reactive transport model coupled with geochemical solver for scale simulations

    NARCIS (Netherlands)

    Patel, R.A.; Perko, J.; Jaques, D.; De Schutter, G.; Ye, G.; Van Breugel, K.

    2013-01-01

    A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multi-component transport model is then coupled with the well

  1. Inverse geochemical modeling of groundwater evolution with emphasis on arsenic in the Mississippi River Valley alluvial aquifer, Arkansas (USA)

    Science.gov (United States)

    Sharif, M.U.; Davis, R.K.; Steele, K.F.; Kim, B.; Kresse, T.M.; Fazio, J.A.

    2008-01-01

    Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater with emphasis on arsenic (As) release under reducing conditions in the shallow (25-30 m) Mississippi River Valley Alluvial aquifer, Arkansas, USA. The modeling was based on flow paths defined by high-precision (??2 cm) water level contour map; X-ray diffraction (XRD), scanning electron microscopic (SEM), and chemical analysis of boring-sediments for minerals; and detailed chemical analysis of groundwater along the flow paths. Potential phases were constrained using general trends in chemical analyses data of groundwater and sediments, and saturation indices data (MINTEQA2) of minerals in groundwater. Modeling results show that calcite, halite, fluorite, Fe oxyhydroxide, organic matter, H2S (gas) were dissolving with mole transfers of 1.40E - 03, 2.13E - 04, 4.15E - 06, 1.25E + 01, 3.11, and 9.34, respectively along the dominant flow line. Along the same flow line, FeS, siderite, and vivianite were precipitating with mole transfers of 9.34, 3.11, and 2.64E - 07, respectively. Cation exchange reactions of Ca2+ (4.93E - 04 mol) for Na+ (2.51E - 04 mol) on exchange sites occurred along the dominant flow line. Gypsum dissolution reactions were dominant over calcite dissolution in some of the flow lines due to the common ion effect. The concentration of As in groundwater ranged from modeling indicate that reductive dissolution of Fe oxyhydroxide is the dominant process of As release in the groundwater. The relative rate of reduction of Fe oxyhydroxide over SO42 - with co-precipitation of As into sulfide is the limiting factor controlling dissolved As in groundwater. ?? 2007 Elsevier B.V. All rights reserved.

  2. Characterizing uncertainties in recent trends of global terrestrial net primary production through ensemble modeling

    Science.gov (United States)

    Wang, W.; Hashimoto, H.; Ganguly, S.; Votava, P.; Nemani, R. R.; Myneni, R. B.

    2010-12-01

    Large uncertainties exist in our understanding of the trends and variability in global net primary production (NPP) and its controls. This study attempts to address this question through a multi-model ensemble experiment. In particular, we drive ecosystem models including CASA, LPJ, Biome-BGC, TOPS-BGC, and BEAMS with a long-term climate dataset (i.e., CRU-NCEP) to estimate global NPP from 1901 to 2009 at a spatial resolution of 0.5 x 0.5 degree. We calculate the trends of simulated NPP during different time periods and test their sensitivities to climate variables of solar radiation, air temperature, precipitation, vapor pressure deficit (VPD), and atmospheric CO2 levels. The results indicate a large diversity among the simulated NPP trends over the past 50 years, ranging from nearly no trend to an increasing trend of ~0.1 PgC/yr. Spatial patterns of the NPP generally show positive trends in boreal forests, induced mainly by increasing temperatures in these regions; they also show negative trends in the tropics, although the spatial patterns are more diverse. These diverse trends result from different climatic sensitivities of NPP among the tested models. Depending the ecological processes (e.g., photosynthesis or respiration) a model emphasizes, it can be more or less responsive to changes in solar radiation, temperatures, water, or atmospheric CO2 levels. Overall, these results highlight the limit of current ecosystem models in simulating NPP, which cannot be easily observed. They suggest that the traditional single-model approach is not ideal for characterizing trends and variability in global carbon cycling.

  3. Optimization of end-members used in multiple linear regression geochemical mixing models

    Science.gov (United States)

    Dunlea, Ann G.; Murray, Richard W.

    2015-11-01

    Tracking marine sediment provenance (e.g., of dust, ash, hydrothermal material, etc.) provides insight into contemporary ocean processes and helps construct paleoceanographic records. In a simple system with only a few end-members that can be easily quantified by a unique chemical or isotopic signal, chemical ratios and normative calculations can help quantify the flux of sediment from the few sources. In a more complex system (e.g., each element comes from multiple sources), more sophisticated mixing models are required. MATLAB codes published in Pisias et al. solidified the foundation for application of a Constrained Least Squares (CLS) multiple linear regression technique that can use many elements and several end-members in a mixing model. However, rigorous sensitivity testing to check the robustness of the CLS model is time and labor intensive. MATLAB codes provided in this paper reduce the time and labor involved and facilitate finding a robust and stable CLS model. By quickly comparing the goodness of fit between thousands of different end-member combinations, users are able to identify trends in the results that reveal the CLS solution uniqueness and the end-member composition precision required for a good fit. Users can also rapidly check that they have the appropriate number and type of end-members in their model. In the end, these codes improve the user's confidence that the final CLS model(s) they select are the most reliable solutions. These advantages are demonstrated by application of the codes in two case studies of well-studied datasets (Nazca Plate and South Pacific Gyre).

  4. Urban net-zero water treatment and mineralization: experiments, modeling and design.

    Science.gov (United States)

    Englehardt, James D; Wu, Tingting; Tchobanoglous, George

    2013-09-01

    Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H2O2 disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10-20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed.

  5. Modeling hydrochory effects on the Tunisian island populations of Pancratium maritimum L. using colored Petri nets.

    Science.gov (United States)

    Sanaa, Adnen; Ben Abid, Samir; Boulila, Abdennacer; Messaoud, Chokri; Boussaid, Mohamed; Ben Fadhel, Najeh

    2015-03-01

    Hydrochory, the seed dispersal by water, is a strategy used by many aquatic and some terrestrial plants to move into areas appropriate for establishment. In this paper we model the hydrochory effects on the Tunisian island populations of Pancratium maritimum L. using colored Petri nets. Nineteen Tunisian coastal sites were considered including fourteen mainland and five island sites. The model was simulated for 400 thousand Atlantic Tunisian Current cycles (years). Snapshots of the island population's genetic makeup were taken for 50, 200 and 400 thousand years. The evolution of the obtained dendrograms showed a clear divide between the northern and southern island populations according to their estimated genetic make-up for the considered simulation durations. Hydrochory is not only with important ecological consequences, such as maintaining the populations of P. maritimum but also it may move species into areas appropriate for establishment. In this context, in situ and ex situ conservation measures of P. maritimum populations should be adopted very fast. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Communication Modeling and Mobile Object Monitoring by Using Colored Petri Nets

    Directory of Open Access Journals (Sweden)

    Dalė Dzemydienė

    2013-08-01

    Full Text Available Monitoring moving objects and analyzing their statuses are the best opportunities currently offered by mobile technology. The methods and software for wireless systems allow the exchange of many possible data formats (e.g., text, visual or audio communication and provide information about the state of the object’s geographical coordinates in real time. The necessary information is received from the sensors and mobile device’s contextual information. Information is sent to remote servers whenever applicable, and, after some calculation, more accurate data is obtained. Software to identify different situations has been designed and implemented. The software and therefore the identification of the situations of technical equipment can send data, warnings or reminders to a given situation. Colored Petri nets (CPN allowed to more precisely model complex situations of scenarios and to capture the information any time, anywhere provided in advance of a moving object. Mobile devices detect the necessary data via the external or internal physical environment through sensors. The mobile device components are interacting with internal or external physical environment and have the sensor detectors’ parameters. Such information is stored into data-warehouses in which the knowledge discovery is made by CPN models, which represent rules of analysis.

  7. Communication Modeling and Mobile Object Monitoring by Using Colored Petri Nets

    Directory of Open Access Journals (Sweden)

    Ramunas Dzindzalieta

    2011-08-01

    Full Text Available Summary. Monitoring moving objects and analyzing their statuses are the best opportunities currently offered by mobile technology. The methods and software for wireless systems allow the exchange of many possible data formats (e.g., text, visual or audio communication and provide information about the state of the object’s geographical coordinates in real time. The necessary information is received from the sensors and mobile device’s contextual information. Information is sent to remote servers whenever applicable, and, after some calculation, more accurate data is obtained. Software to identify different situations has been designed and implemented. The software and therefore the identification of the situations of technical equipment can send data, warnings or reminders to a given situation. Colored Petri nets (CPN allowed to more precisely model complex situations of scenarios and to capture the information any time, anywhere provided in advance of a moving object. Mobile devices detect the necessary data via the external or internal physical environment through sensors. The mobile device components are interacting with internal or external physical environment and have the sensor detectors’ parameters. Such information is stored into data-warehouses in which the knowledge discovery is made by CPN models, which represent rules of analysis.

  8. A Petri-Nets Based Unified Modeling Approach for Zachman Framework Cells

    Science.gov (United States)

    Ostadzadeh, S. Shervin; Nekoui, Mohammad Ali

    With a trend toward becoming more and more information based, enterprises constantly attempt to surpass the accomplishments of each other by improving their information activities. In this respect, Enterprise Architecture (EA) has proven to serve as a fundamental concept to accomplish this goal. Enterprise architecture clearly provides a thorough outline of the whole enterprise applications and systems with their relationships to enterprise business goals. To establish such an outline, a logical framework needs to be laid upon the entire information system called Enterprise Architecture Framework (EAF). Among various proposed EAF, Zachman Framework (ZF) has been widely accepted as a standard scheme for identifying and organizing descriptive representations that have critical roles in enterprise management and development. One of the problems faced in using ZF is the lack of formal and verifiable models for its cells. In this paper, we proposed a formal language based on Petri nets in order to obtain verifiable models for all cells in ZF. The presented method helps developers to validate and verify completely integrated business and IT systems which results in improve the effectiveness or efficiency of the enterprise itself.

  9. Status of geochemical modeling of groundwater evolution at the Tono in-situ tests site, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Sasamoto, Hiroshi; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Arthur, R.C. [Monitor Scientific, L.L.C., Denver, Colorado (United States)

    1999-12-01

    Hydrochemical investigation of Tertiary sedimentary rocks at JNC's Tono in-situ tests site indicate the groundwaters are: meteoric in origin, chemically reducing at depths greater than a few tens of meters in the sedimentary rock, relatively old [carbon-14 ages of groundwaters collected from the lower part of the sedimentary sequence range from 13,000 to 15,000 years BP (before present)]. Ca-Na-HCO{sub 3} type solutions near the surface, changing to Na-HCO{sub 3} type groundwaters with increasing depth. The chemical evolution of the groundwaters is modeled assuming local equilibrium for selected mineral-fluid reactions, taking into account the rainwater origin of these solutions. Results suggest it is possible to interpret approximately the 'real' groundwater chemistry (i.e., pH, Eh, total dissolved concentrations of Si, Na, Ca, K, Al, carbonate and sulfate) if the following assumptions are adopted: CO{sub 2} concentration in the gas phase contacting pore solutions in the overlying soil zone=10{sup -1} bar, minerals in the rock zone that control the solubility of respective elements in the groundwater include; chalcedony (Si), albite (Na), kaolinite (Al), calcite (Ca and carbonate), muscovite (K) and pyrite (Eh and sulfate). It is noted, however, that the available field data may not be sufficient to adequately constrain parameters in the groundwater evolution model. In particular, more detailed information characterizing certain site properties (e.g., the actual mineralogy of 'plagioclase', 'clay' and 'zeolite') are needed to improve the model. Alternative conceptual models of key reactions may also be necessary. For this reason, a model that accounts for ion-exchange reactions among clay minerals, and which is based on the results of laboratory experiments, has also been evaluated in the present study. Further improvements of model considering ion-exchange reactions are needed in future, however. (author)

  10. Incorporating Geochemical And Microbial Kinetics In Reactive Transport Models For Generation Of Acid Rock Drainage

    Science.gov (United States)

    Andre, B. J.; Rajaram, H.; Silverstein, J.

    2010-12-01

    Acid mine drainage, AMD, results from the oxidation of metal sulfide minerals (e.g. pyrite), producing ferrous iron and sulfuric acid. Acidophilic autotrophic bacteria such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans obtain energy by oxidizing ferrous iron back to ferric iron, using oxygen as the electron acceptor. Most existing models of AMD do not account for microbial kinetics or iron geochemistry rigorously. Instead they assume that oxygen limitation controls pyrite oxidation and thus focus on oxygen transport. These models have been successfully used for simulating conditions where oxygen availability is a limiting factor (e.g. source prevention by capping), but have not been shown to effectively model acid generation and effluent chemistry under a wider range of conditions. The key reactions, oxidation of pyrite and oxidation of ferrous iron, are both slow kinetic processes. Despite being extensively studied for the last thirty years, there is still not a consensus in the literature about the basic mechanisms, limiting factors or rate expressions for microbially enhanced oxidation of metal sulfides. An indirect leaching mechanism (chemical oxidation of pyrite by ferric iron to produce ferrous iron, with regeneration of ferric iron by microbial oxidation of ferrous iron) is used as the foundation of a conceptual model for microbially enhanced oxidation of pyrite. Using literature data, a rate expression for microbial consumption of ferrous iron is developed that accounts for oxygen, ferrous iron and pH limitation. Reaction rate expressions for oxidation of pyrite and chemical oxidation of ferrous iron are selected from the literature. A completely mixed stirred tank reactor (CSTR) model is implemented coupling the kinetic rate expressions, speciation calculations and flow. The model simulates generation of AMD and effluent chemistry that qualitatively agrees with column reactor and single rock experiments. A one dimensional reaction

  11. Modeling reactive geochemical transport of concentrated aqueous solutions in variably saturated media

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guoxiang; Zheng, Zuoping; Wan, Jiamin

    2004-01-28

    Concentrated aqueous solutions (CAS) have unique thermodynamic and physical properties. Chemical components in CAS are incompletely dissociated, especially those containing divalent or polyvalent ions. The problem is further complicated by the interaction between CAS flow processes and the naturally heterogeneous sediments. As the CAS migrates through the porous media, the composition may be altered subject to fluid-rock interactions. To effectively model reactive transport of CAS, we must take into account ion-interaction. A combination of the Pitzer ion-interaction and the ion-association model would be an appropriate way to deal with multiple-component systems if the Pitzer' parameters and thermodynamic data of dissolved components and the related minerals are available. To quantify the complicated coupling of CAS flow and transport, as well as the involved chemical reactions in natural and engineered systems, we have substantially extended an existing reactive biogeochemical transport code, BIO-CORE{sup 2D}{copyright}, by incorporating a comprehensive Pitzer ion-interaction model. In the present paper, the model, and two test cases against measured data were briefly introduced. Finally we present an application to simulate a laboratory column experiment studying the leakage of the high alkaline waste fluid stored in Hanford (a site of the U.S. Department of Energy, located in Washington State, USA). With the Pitzer ion-interaction ionic activity model, our simulation captures measured pH evolution. The simulation indicates that all the reactions controlling the pH evolution, including cation exchanges, mineral precipitation and dissolution, are coupled.

  12. Construction and Experimental Validation of a Petri Net Model of Wnt/β-Catenin Signaling.

    Directory of Open Access Journals (Sweden)

    Annika Jacobsen

    Full Text Available The Wnt/β-catenin signaling pathway is important for multiple developmental processes and tissue maintenance in adults. Consequently, deregulated signaling is involved in a range of human diseases including cancer and developmental defects. A better understanding of the intricate regulatory mechanism and effect of physiological (active and pathophysiological (hyperactive WNT signaling is important for predicting treatment response and developing novel therapies. The constitutively expressed CTNNB1 (commonly and hereafter referred to as β-catenin is degraded by a destruction complex, composed of amongst others AXIN1 and GSK3. The destruction complex is inhibited during active WNT signaling, leading to β-catenin stabilization and induction of β-catenin/TCF target genes. In this study we investigated the mechanism and effect of β-catenin stabilization during active and hyperactive WNT signaling in a combined in silico and in vitro approach. We constructed a Petri net model of Wnt/β-catenin signaling including main players from the plasma membrane (WNT ligands and receptors, cytoplasmic effectors and the downstream negative feedback target gene AXIN2. We validated that our model can be used to simulate both active (WNT stimulation and hyperactive (GSK3 inhibition signaling by comparing our simulation and experimental data. We used this experimentally validated model to get further insights into the effect of the negative feedback regulator AXIN2 upon WNT stimulation and observed an attenuated β-catenin stabilization. We furthermore simulated the effect of APC inactivating mutations, yielding a stabilization of β-catenin levels comparable to the Wnt-pathway activities observed in colorectal and breast cancer. Our model can be used for further investigation and viable predictions of the role of Wnt/β-catenin signaling in oncogenesis and development.

  13. Marine geochemical data assimilation in an efficient Earth System Model of global biogeochemical cycling

    Directory of Open Access Journals (Sweden)

    A. Ridgwell

    2007-01-01

    Full Text Available We have extended the 3-D ocean based "Grid ENabled Integrated Earth system model" (GENIE-1 to help understand the role of ocean biogeochemistry and marine sediments in the long-term (~100 to 100 000 year regulation of atmospheric CO2, and the importance of feedbacks between CO2 and climate. Here we describe the ocean carbon cycle, which in its first incarnation is based around a simple single nutrient (phosphate control on biological productivity. The addition of calcium carbonate preservation in deep-sea sediments and its role in regulating atmospheric CO2 is presented elsewhere (Ridgwell and Hargreaves, 2007. We have calibrated the model parameters controlling ocean carbon cycling in GENIE-1 by assimilating 3-D observational datasets of phosphate and alkalinity using an ensemble Kalman filter method. The calibrated (mean model predicts a global export production of particulate organic carbon (POC of 8.9 PgC yr−1, and reproduces the main features of dissolved oxygen distributions in the ocean. For estimating biogenic calcium carbonate (CaCO3 production, we have devised a parameterization in which the CaCO3:POC export ratio is related directly to ambient saturation state. Calibrated global CaCO3 export production (1.2 PgC yr-1 is close to recent marine carbonate budget estimates. The GENIE-1 Earth system model is capable of simulating a wide variety of dissolved and isotopic species of relevance to the study of modern global biogeochemical cycles as well as past global environmental changes recorded in paleoceanographic proxies. Importantly, even with 12 active biogeochemical tracers in the ocean and including the calculation of feedbacks between atmospheric CO2 and climate, we achieve better than 1000 years per (2.4 GHz CPU hour on a desktop PC. The GENIE-1 model thus provides a viable alternative to box and zonally-averaged models for studying global biogeochemical cycling over all but the very longest (>1 000 000 year time-scales.

  14. Marine geochemical data assimilation in an efficient Earth System Model of global biogeochemical cycling

    Directory of Open Access Journals (Sweden)

    A. Ridgwell

    2006-08-01

    Full Text Available We have extended the 3-D ocean based "Grid ENabled Integrated Earth system model'' (GENIE-1 to help understand the role of ocean biogeochemistry and marine sediments in the "long-term'' (~100 to 100 000 year regulation of atmospheric CO2, and the importance of feedbacks between CO2 and climate. Here we describe the ocean carbon cycle, which is based around a simple single nutrient (phosphate control on biological productivity. The addition of ocean-sediment interactions is presented elsewhere (Ridgwell and Hargreaves, 2006.

    We have calibrated the model parameters controlling ocean carbon cycling in GENIE-1 by assimilating 3-D observational datasets of phosphate and alkalinity using an ensemble Kalman filter method. The calibrated (mean model predicts a global export production of particulate organic carbon (POC of 8.9 PgC yr−1, and reproduces the main features of dissolved oxygen distributions in the ocean. For estimating biogenic calcium carbonate (CaCO3 production, we have devised a parameterization in which the CaCO3:POC export ratio is related directly to ambient saturation state. Calibrated global CaCO3 export production (1.2 PgC yr−1 is close to recent marine carbonate budget estimates.

    The GENIE-1 Earth system model is capable of simulating a wide variety of dissolved and isotopic species of relevance to the study of modern global biogeochemical cycles as well as past global environmental changes recorded in paleoceanographic proxies. Importantly, even with 12 active biogeochemical tracers in the ocean and including the calculation of feedbacks between atmospheric CO2 and climate, we achieve better than 1000 years per (2.4 GHz CPU hour on a desktop PC. The GENIE-1 model thus provides a viable alternative to box and zonally-averaged models for studying global biogeochemical cycling over all but the very longest

  15. Predictive modeling of CO2 sequestration in deep saline sandstone reservoirs: Impacts of geochemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Balashov, Victor N.; Guthrie, George D.; Hakala, J. Alexandra; Lopano, Christina L.; Rimstidt, J. Donald; Brantley, Susan L.

    2013-03-01

    One idea for mitigating the increase in fossil-fuel generated CO{sub 2} in the atmosphere is to inject CO{sub 2} into subsurface saline sandstone reservoirs. To decide whether to try such sequestration at a globally significant scale will require the ability to predict the fate of injected CO{sub 2}. Thus, models are needed to predict the rates and extents of subsurface rock-water-gas interactions. Several reactive transport models for CO{sub 2} sequestration created in the last decade predicted sequestration in sandstone reservoirs of ~17 to ~90 kg CO{sub 2} m{sup -3|. To build confidence in such models, a baseline problem including rock + water chemistry is proposed as the basis for future modeling so that both the models and the parameterizations can be compared systematically. In addition, a reactive diffusion model is used to investigate the fate of injected supercritical CO{sub 2} fluid in the proposed baseline reservoir + brine system. In the baseline problem, injected CO{sub 2} is redistributed from the supercritical (SC) free phase by dissolution into pore brine and by formation of carbonates in the sandstone. The numerical transport model incorporates a full kinetic description of mineral-water reactions under the assumption that transport is by diffusion only. Sensitivity tests were also run to understand which mineral kinetics reactions are important for CO{sub 2} trapping. The diffusion transport model shows that for the first ~20 years after CO{sub 2} diffusion initiates, CO{sub 2} is mostly consumed by dissolution into the brine to form CO{sub 2,aq} (solubility trapping). From 20-200 years, both solubility and mineral trapping are important as calcite precipitation is driven by dissolution of oligoclase. From 200 to 1000 years, mineral trapping is the most important sequestration mechanism, as smectite dissolves and calcite precipitates. Beyond 2000 years, most trapping is due to formation of aqueous HCO{sub 3}{sup -}. Ninety-seven percent of the

  16. A Compilation of Rate Parameters of Water-Mineral Interaction Kinetics for Application to Geochemical Modeling

    Science.gov (United States)

    2004-03-01

    Experimental study of the hydrothermal formation of kaolinite. Chem. Geol. 156, 171-190. Hull A. B. and Hull J. R. (1987) Geometric modeling of...A. and Barnes H. L. (1991a) Mechanisms of pyrite and marcasite formation from solution: III. Hydrothermal processes. Geochim. Cosmochim. Acta 55...12 3.1.1.2 Amorphous SiO2, Cristobalite , and SiO2 Polymorph Precipitation...................... 14 3.1.2 Feldspars

  17. Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

    OpenAIRE

    Lee, Younjoo J.; Matrai, Patricia A.; Friedrichs, Marjorie A. M; Vincent S. Saba; Aumont, Olivier; Babin, Marcel; Buitenhuis, Erik T.; Chevallier, Matthieu; de Mora, Lee; Dessert, Morgane; Dunne, John P.; Ellingsen, Ingrid; Feldman, Doron; Frouin, Robert; Gehlen, Marion

    2016-01-01

    The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO3), mixed layer depth (MLD), euphotic layer depth (Zeu), and sea ice concentration, by comparing results against a newly updated, quality-controlled in situ NPP database for the Arctic Ocean (1959-2011). The models broadly captured the spatial features of integrated NPP (i...

  18. Application of Thermal Modelling for Geochemical Characterization of Gadvan Formation, Persian Gulf, Iran

    Directory of Open Access Journals (Sweden)

    Ahmad Vaezian

    2014-12-01

    Full Text Available In the this research, the hydrocarbon generation potential of the Gadvan Formation as a probable source rock was investigated in the central part of the Persian Gulf at the borders of Iran. Type and maturity level of kerogen were investigated in six wells using the results of Rock-Eval pyrolysis and compared with results yielded by the modelling software program known as Pars Basin Modeler (PBM. The cross-plot of hydrogen index (HI versus maximum temperature suggests that the Gadvan Formation reached early to mid-maturity stages in the studied area, which means that it could act as a gas prone source rock. Furthermore, the burial and thermal history of the Gadvan Formation was determined in one well. Two methods, Easy %Ro and time-temperature index (TTI were used for the reconstruction of thermal modelling and studying the thermal maturity level in all of the drilled wells reaching the Gadvan Formation. The results of the TTI and Easy %Ro methods were in good agreement and both of confirmed the results of Rock Eval analysis. An integrated approach using different techniques showed that the Gadvan Formation can be classified as a poor gas bearing source rock in the studied area, while its maturity increases towards the southern parts of the Persian Gulf.

  19. Modelling the limits on the response of net carbon exchange to fertilization in a south-eastern pine forest

    Science.gov (United States)

    Chun-Tai. Lai; G. Katul; J. Butnor; M. Siqueira; D. Ellsworth; C. Maier; Kurt Johnsen; S. Mickeand; R. Oren

    2002-01-01

    Using a combination of model simulations and detailed measurements at a hierarchy of scales conducted at a sandhills forest site, the effect of fertilization on net ecosystem exchange (NEE) and its components in 6-year-old Pinus taeda stands was quantified. The detailed measurements, collected over a 20-d period in September and October, included gas...

  20. Transparency about net neutrality : A translation of the new European rules into a multi-stakeholder model

    NARCIS (Netherlands)

    Nooren, P.; Prins, M.J.

    2011-01-01

    The new European framework directive contains a number of policy objectives in the area of net neutrality. In support of these objectives, the universal service directive includes a transparency obligation for ISPs. This paper proposes a multi-stakeholder model for the implementation of this transpa

  1. Game Coloured Petri Nets

    DEFF Research Database (Denmark)

    Westergaard, Michael

    2006-01-01

    This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachabilit......, and not controllable by the system itself, or they are part of the system itself and therefore we need not worry about them)....

  2. Produced water re-injection in a non-fresh water aquifer with geochemical reaction, hydrodynamic molecular dispersion and adsorption kinetics controlling: model development and numerical simulation

    Science.gov (United States)

    Obe, Ibidapo; Fashanu, T. A.; Idialu, Peter O.; Akintola, Tope O.; Abhulimen, Kingsley E.

    2017-06-01

    An improved produced water reinjection (PWRI) model that incorporates filtration, geochemical reaction, molecular transport, and mass adsorption kinetics was developed to predict cake deposition and injectivity performance in hydrocarbon aquifers in Nigeria oil fields. Thus, the improved PWRI model considered contributions of geochemical reaction, adsorption kinetics, and hydrodynamic molecular dispersion mechanism to alter the injectivity and deposition of suspended solids on aquifer wall resulting in cake formation in pores during PWRI and transport of active constituents in hydrocarbon reservoirs. The injectivity decline and cake deposition for specific case studies of hydrocarbon aquifers in Nigeria oil fields were characterized with respect to its well geometry, lithology, and calibrations data and simulated in COMSOL multiphysics software environment. The PWRI model was validated by comparisons to assessments of previous field studies based on data and results supplied by operator and regulator. The results of simulation showed that PWRI performance was altered because of temporal variations and declinations of permeability, injectivity, and cake precipitation, which were observed to be dependent on active adsorption and geochemical reaction kinetics coupled with filtration scheme and molecular dispersion. From the observed results and findings, transition time t r to cake nucleation and growth were dependent on aquifer constituents, well capacity, filtration coefficients, particle-to-grain size ratio, water quality, and more importantly, particle-to-grain adsorption kinetics. Thus, the results showed that injectivity decline and permeability damage were direct contributions of geochemical reaction, hydrodynamic molecular diffusion, and adsorption kinetics to the internal filtration mechanism, which are largely dependent on the initial conditions of concentration of active constituents of produced water and aquifer capacity.

  3. Produced water re-injection in a non-fresh water aquifer with geochemical reaction, hydrodynamic molecular dispersion and adsorption kinetics controlling: model development and numerical simulation

    Science.gov (United States)

    Obe, Ibidapo; Fashanu, T. A.; Idialu, Peter O.; Akintola, Tope O.; Abhulimen, Kingsley E.

    2016-12-01

    An improved produced water reinjection (PWRI) model that incorporates filtration, geochemical reaction, molecular transport, and mass adsorption kinetics was developed to predict cake deposition and injectivity performance in hydrocarbon aquifers in Nigeria oil fields. Thus, the improved PWRI model considered contributions of geochemical reaction, adsorption kinetics, and hydrodynamic molecular dispersion mechanism to alter the injectivity and deposition of suspended solids on aquifer wall resulting in cake formation in pores during PWRI and transport of active constituents in hydrocarbon reservoirs. The injectivity decline and cake deposition for specific case studies of hydrocarbon aquifers in Nigeria oil fields were characterized with respect to its well geometry, lithology, and calibrations data and simulated in COMSOL multiphysics software environment. The PWRI model was validated by comparisons to assessments of previous field studies based on data and results supplied by operator and regulator. The results of simulation showed that PWRI performance was altered because of temporal variations and declinations of permeability, injectivity, and cake precipitation, which were observed to be dependent on active adsorption and geochemical reaction kinetics coupled with filtration scheme and molecular dispersion. From the observed results and findings, transition time t r to cake nucleation and growth were dependent on aquifer constituents, well capacity, filtration coefficients, particle-to-grain size ratio, water quality, and more importantly, particle-to-grain adsorption kinetics. Thus, the results showed that injectivity decline and permeability damage were direct contributions of geochemical reaction, hydrodynamic molecular diffusion, and adsorption kinetics to the internal filtration mechanism, which are largely dependent on the initial conditions of concentration of active constituents of produced water and aquifer capacity.

  4. Geochemical modelling and speciation studies of metal pollutants present in selected water systems in South Africa

    Science.gov (United States)

    Magu, M. M.; Govender, P. P.; Ngila, J. C.

    2016-04-01

    Metal pollutants in water poses great threats to living beings and hence requires to be monitored regularly to avoid loss of lives. Various analytical methods are available to monitor these pollutants in water and can be improved with time. Modelling of metal pollutants in any water system helps chemists, engineers and environmentalists to greatly understand the various chemical processes in such systems. Water samples were collected from waste water treatment plant and river from highlands close to its source all the way to the ocean as it passing through areas with high anthropogenic activities. Pre-concentration of pollutants in the samples was done through acid digestion and metal pollutants were analysed using inductively coupled plasma-optical emission spectra (ICP-OES) to determine the concentration levels. Metal concentrations ranged between 0.1356-0.4658 mg/L for Al; 0.0031-0.0050 mg/L for Co, 0.0019-0.0956 mg/L for Cr; 0.0028-0.3484 mg/L for Cu; 0.0489-0.3474 mg/L for Fe; 0.0033-0.0285 mg/L for Mn; 0.0056-0.0222 mg/L for Ni; 0.0265-0.4753 mg/L for Pb and 0.0052-0.5594 mg/L for Zn. Modelling work was performed using PHREEQC couple with Geochemist's workbench (GWB) to determine speciation dynamics and bioavailability of these pollutants. Modelling thus adds value to analytical methods and hence a better complementary tool to laboratory-based experimental studies.

  5. Modeling electroencephalography waveforms with semi-supervised deep belief nets: fast classification and anomaly measurement

    Science.gov (United States)

    Wulsin, D. F.; Gupta, J. R.; Mani, R.; Blanco, J. A.; Litt, B.

    2011-06-01

    Clinical electroencephalography (EEG) records vast amounts of human complex data yet is still reviewed primarily by human readers. Deep belief nets (DBNs) are a relatively new type of multi-layer neural network commonly tested on two-dimensional image data but are rarely applied to times-series data such as EEG. We apply DBNs in a semi-supervised paradigm to model EEG waveforms for classification and anomaly detection. DBN performance was comparable to standard classifiers on our EEG dataset, and classification time was found to be 1.7-103.7 times faster than the other high-performing classifiers. We demonstrate how the unsupervised step of DBN learning produces an autoencoder that can naturally be used in anomaly measurement. We compare the use of raw, unprocessed data—a rarity in automated physiological waveform analysis—with hand-chosen features and find that raw data produce comparable classification and better anomaly measurement performance. These results indicate that DBNs and raw data inputs may be more effective for online automated EEG waveform recognition than other common techniques.

  6. Modeling the Economic Feasibility of Large-Scale Net-Zero Water Management: A Case Study.

    Science.gov (United States)

    Guo, Tianjiao; Englehardt, James D; Fallon, Howard J

      While municipal direct potable water reuse (DPR) has been recommended for consideration by the U.S. National Research Council, it is unclear how to size new closed-loop DPR plants, termed "net-zero water (NZW) plants", to minimize cost and energy demand assuming upgradient water distribution. Based on a recent model optimizing the economics of plant scale for generalized conditions, the authors evaluated the feasibility and optimal scale of NZW plants for treatment capacity expansion in Miami-Dade County, Florida. Local data on population distribution and topography were input to compare projected costs for NZW vs the current plan. Total cost was minimized at a scale of 49 NZW plants for the service population of 671,823. Total unit cost for NZW systems, which mineralize chemical oxygen demand to below normal detection limits, is projected at ~$10.83 / 1000 gal, approximately 13% above the current plan and less than rates reported for several significant U.S. cities.

  7. Regional differences in modelled net production and shallow remineralization in the North Atlantic subtropical Gyre

    Directory of Open Access Journals (Sweden)

    B. Fernández-Castro

    2011-12-01

    Full Text Available We used 5-year concomitant data of tracers distribution from the BATS (Bermuda Time-series Study and ESTOC (European Station for Time-Series in the Ocean, Canary Islands sites to build a 1-D tracer model conservation including horizontal advection and compute net production and shallow remineralization rates at both sites. Net production rates computed below the mixed layer to 110 m from April to December for oxygen, dissolved inorganic carbon and nitrate at BATS (1.34 ± 0.79 mol O2 m−2, −1.73 ± 0.52 mol C m−2 and −125 ± 36 mmol N m−2 showed no statistically significant differences compared to ESTOC (1.03 ± 0.62 mol O2 m−2, −1.42 ± 0.30 mol C m−2 and −213 ± 56 mmol N m−2. Shallow remineralization rates between 110 and 250 m computed at ESTOC (−3.9 ± 1.0 mol O2 m−2, 1.53 ± 0.43 mol C m−2 and 38 ± 155 mmol N m−2 were statistically higher for oxygen compared to BATS (−1.81 ± 0.37 mol O2 m−2, 1.52 ± 0.30 mol C m−2 and 147 ± 43 mmol N m−2. Lateral advection, which was more significant at ESTOC, was responsible for the differences in estimated oxygen remineralization rates between both stations. Due to the relevance of the horizontal transport at ESTOC, we cannot assert that the differences in shallow remineralization rates computed for both stations can explain the observed descrepancies in the flux of sinking organic matter.

  8. Modelling of long term geochemical evolution and study of mechanical perturbation of bentonite buffer of a KBS-3 repository

    Energy Technology Data Exchange (ETDEWEB)

    Marsal, Francois; Pellegrini, Delphine; Deleruyelle, Frederic; Serres, Christophe (French Inst. for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses (FR)); Windt, Laurent de (Ecole des Mines de Paris, Paris (FR))

    2008-03-15

    PART I: The Swedish Nuclear Fuel and Waste Management Co. (SKB) has recently completed a safety assessment project named SR-Can, related to the KBS-3 disposal concept. In this concept, the waste packages are surrounded by a buffer made of either MX-80 or Deponit CA-N bentonite. Interactions between the buffer and groundwater may modify the buffer composition and thus its containment properties. The Swedish Radiation Protection Authorities (SSI) requested the French Institute for Radiological Protection and Nuclear Safety (IRSN) to perform the present study in support of SSI review of the SR-Can report. The purpose is to assess the geochemical evolution of both potential buffer materials due to the intrusion of different types of groundwater, with a similar modelling layout to that reported in SR-Can and detailed in Arcos et al. Three main categories of water inflows via a fracture intersecting a deposition hole are considered: the Forsmark reference groundwater, a high-salinity groundwater to account for up-rise of deep-seated brines and a diluted water representing ice-melting derived-groundwater. In addition to this, the redox buffering capacity of Deponit CA-N bentonite and the thermal effect on MX-80 bentonite geochemistry have been assessed. This modelling work has been performed using the reactive transport modelling code HYTEC. The main outcome of the present study is that the intrusion of the considered groundwaters should not affect drastically the geochemistry of neither the Deponit CA-N nor the MX-80 bentonite on the longterm (100,000 y). Bentonite pH may reach high values (up to 10.5) in some cases but does not reach SKB criterion value related to bentonite chemical stability. Dissolution-precipitation of accessory minerals is not significant enough to induce important porosity changes (rise by maximum 2 %). Globally, the montmorillonite exchanger undergoes Na by Ca partial replacement, which may decrease the swelling pressure of the bentonite. The

  9. Intercomparison of Cement Solid-Solution Models. Issues Affecting the Geochemical Evolution of Repositories for Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    Benbow, Steven; Savage, David [Quintessa Ltd., Henley-on-Thames (United Kingdom); Walker, Colin [Dept. of Mineralogy, The Natural History Museum London (United Kingdom)

    2007-05-15

    Many concepts for the geological storage of radioactive waste incorporate cement based materials, which act to provide a chemical barrier, impede groundwater flow or provide structural integrity of the underground structures. Thus, it is important to understand the long-term behaviour of these materials when modelling scenarios for the potential release and migration of radionuclides. In the presence of invasive groundwater, the chemical and physical properties of cement, such as its pH buffering capacity, resistance to flow, and its mechanical properties, are expected to evolve with time. Modelling the degradation of cement is complicated by the fact that the long term pH buffer is controlled by the incongruent dissolution behaviour of calcium-silicate-hydrate (C-S-H) gel. It has been previously shown (SKI Report 2005:64) that it is possible to simulate the long term evolution of both the physical and chemical properties of cement based materials in an invasive groundwater using a fully coupled geochemical transport model. The description of the incongruent dissolution of C-S-H gel was based on a binary solid solution aqueous solution (SSAS) between end-member components portlandite (Ca(OH){sub 2}) and a C-S-H gel composition expressed by its component oxides (CaH{sub 2}SiO{sub 4}). The models considered a range of uncertainties including different groundwater compositions, parameterised couplings between the evolution of porosity with permeability and diffusivity and alternative secondary mineral assemblages. The results of the modelling suggested that alternative evolutions were possible under these different conditions. The focus of this report is to address the uncertainty regarding the choice of model for the C-S-H gel dissolution. We compare two alternative C-S-H SSAS models with the one that was used in the previous report, with an emphasis on a direct comparison of the model predictions. Thus we have chosen one simple simulated experimental model based on

  10. Coloured Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt

    1991-01-01

    This paper describes how Coloured Petri Nets (CP-nets) have been developed — from being a promising theoretical model to being a full-fledged language for the design, specification, simulation, validation and implementation of large software systems (and other systems in which human beings and...... use of CP-nets — because it means that the function representation and the translations (which are a bit mathematically complex) no longer are parts of the basic definition of CP-nets. Instead they are parts of the invariant method (which anyway demands considerable mathematical skills...

  11. Laboratory Experiments Concerning Upwellings From the Slab-Graveyard: Implications For Geochemical and Seismic Models

    Science.gov (United States)

    Harris, A. C.; Kincaid, C.; Hall, P.

    2005-12-01

    The ongoing plume debate appears to focus on upwellings characterized by large heads and smaller tails, that form from a deep or basal thermal boundary layer (BTBL), which are driven by temperature excesses in the range of 200° C. We use 3-D laboratory experiments to explore how upwellings might differ from this common plume description when BTBLs are influenced by subducted plates. An important aspect of the models is the representation of ridge chemical differentiation processes resulting in slabs with two distinct layers; a lighter, depleted upper mantle component (Harzburgite:H) and a heavier, iron-rich crustal component (Basalt/Eclogite:B/E). Laboratory experiments utilize a working fluid of glucose syrup with temperature dependent density and viscosity. Compositionally distinct mantle reservoirs are represented through isothermal density/viscosity contrasts controlled by water content. The ambient fluid (AF) is contained within a rectangular tank that is heated from below and cooled from above to produce background convection with a Rayleigh number of 10-5-10-6. Highly viscous, tabular slabs are produced by pouring compositionally distinct syrup from two slab reservoirs (B/E and H) into a mold which is chilled to -5° C. The viscous layered slab is emplaced at the fluid surface and subsequently sinks through, stalls and spreads within a BTBL roughly twice the slab thickness (1 cm). Results show that a wide variety in upwelling morphologies form when layered slabs reside within the BTBL and that plume heads/tails are largely dissimilar to those of the standard plume model. The manner in which the slab laminae vs. AF in the BTBL combine (or segregate) within upwellings depends on viscosity/density contrasts, how slabs collapse in the BTBL, and time. End-member regimes include: experiments dominated by a very light H-slab component with early, cold H-plumes and late, hot B/E-AF plumes and experiments where density differences between H, B/E and AF are small and

  12. Geochemical Impact on the Caprock Porous Structure during CO2 Geological Storage : A Laboratory and Modeling Study

    Science.gov (United States)

    Rhenals Garrido, D. R.; Lafortune, S.; Souli, H.; Dubujet, P.

    2013-12-01

    CO2 storage is envisioned as a technique which reduces large quantities of CO2 rejected in the atmosphere because of many human activities. The effectiveness of this technique is mainly related to the storage capacity as well as its safety. The safety of this operation is primarily based on the conservation of petro-physical properties of the caprock, which prevents the transport of CO2 towards the surface. However when CO2 reaches the reservoir/caprock interface due to buoyancy effects, the interaction between interstitial fluid and injected fluid creates a serie of dissolution/precipitation reactions affecting the properties of containment of the caprock, which is generally characterized by low transport properties. This study aims to assess the impact caused by CO2/interstitial fluid interaction on the nanostructure of a caprock under geological storage conditions. In order to do this, degradation experiments at high pressure of CO2 (88 bar) and isothermal (55°C) conditions have been conducted using batch reactors for 3.5 months. The sample used for these experiments is a well characterized shale, from the Tournemire formation (Aveyron-France). Porosity evolution has been followed by using volumetric adsorption at low pressure, from advanced NLFDT and classical theories based on the micropores filling, and capillary condensation phenomena. Results showed a slight variation in both mesopores and micropores size distributions, as a result of dissolution processes, which dominated at laboratoty time scale. Furthermore, chemical analysis from the water sampled showed an overall increase in Ca,Mg,K,Si,Na. The results obtained by physical adsorption and water chemistry analysis were consistent, with geochemical modeling, which suggested reaction paths with calcite dissolution as the main mineral, by producing porosity at short term and (clays, feldspars) dissolution of aluminosilicates dominating at long term.

  13. Alligator Rivers Analogue project. Geochemical modelling of secondary uranium ore formation. Final Report - Volume 11

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, D. [The John Hopkins Univ, Dept of Earth and Planetary Sciences, Baltimore (United States); Bennett, D.G.; Read, D. [W.S. Atkins Science and Technology, Epsom Surrey, (United Kingdom)

    1992-12-31

    The purpose of the present study was to establish how the uranyl phosphate zone at the Koongarra site was formed. The overall approach taken in the present study employed theoretical chemical mass transfer calculations and models that permit investigation and reconstruction of the kinds of waters that could produce the uranyl phosphate zone. These calculations have used the geological and mineralogical data for the Koongarra weathered zone (Volumes 2, 8, and 9 of this series), to constrain the initial compositions and reactions undergone by groundwater during the formation of the uranyl phosphate zone. In carrying out these calculations the present-day analyses of Koongarra waters are used only as a guide to the possible initial composition of the fluids associated with the formation of the phosphate zone. Aqueous speciation, saturation state and chemical mass transfer calculations were carried out using the computer programs EQ3NR and EQ6 (Wolery, 1983; Wolery et al., 1984) and a thermodynamic database generated at The Johns Hopkins University over the last eight years which is tabulated in the Appendix 1 to Volume 12 of this series. Despite uncertainties in the thermodynamic characterisation of species, all the above calculations suggest that the uranyl phosphate zone at Koongarra has not formed from present-day groundwaters (Volume 12 of this series). The present-day groundwaters in the weathered zone (eg. at 13 m depth) appear to be undersaturated with respect to saleeite. Furthermore, as present-day groundwaters descend below the water table they rapidly lose their atmospheric oxygen imprint, as is typical of most groundwaters, and become even more reducing in character. Under these circumstances, the groundwaters become more undersaturated with respect to saleeite than the shallow groundwaters. Because much of the phosphate zone is currently below the water table, under saturated zone conditions, it is suggested in the present study that the uranyl phosphate

  14. Effects of volume corrections and resonance decays on cumulants of net-charge distributions in a Monte Carlo hadron resonance gas model

    Science.gov (United States)

    Xu, Hao-jie

    2017-02-01

    The effects of volume corrections and resonance decays (the resulting correlations between positive charges and negative charges) on cumulants of net-proton distributions and net-charge distributions are investigated by using a Monte Carlo hadron resonance gas (MCHRG) model. The required volume distributions are generated by a Monte Carlo Glauber (MC-Glb) model. Except the variances of net-charge distributions, the MCHRG model with more realistic simulations of volume corrections, resonance decays and acceptance cuts can reasonably explain the data of cumulants of net-proton distributions and net-charge distributions reported by the STAR collaboration. The MCHRG calculations indicate that both the volume corrections and resonance decays make the cumulant products of net-charge distributions deviate from the Skellam expectations: the deviations of Sσ and κσ2 are dominated by the former effect while the deviations of ω are dominated by the latter one.

  15. IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

    Science.gov (United States)

    Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

  16. Modeling and Solving the Three Seaside Operational Problems Using an Object-Oriented and Timed Predicate/Transition Net

    Directory of Open Access Journals (Sweden)

    Hsien-Pin Hsu

    2017-02-01

    Full Text Available Container terminals (CTs play an essential role in the global transportation system. To deal with growing container shipments, a CT needs to better solve the three essential seaside operational problems; berth allocation problem (BAP, quay crane assignment problem (QCAP, and quay crane scheduling problem (QCSP, which affect the performance of a CT considerably. In past studies, the three seaside operational problems have often been solved individually or partially, which is likely to result in poor overall system performance. However, solving the three seaside operational problems simultaneously is in fact a very complicated task. In this research, we dealt with the three seaside operational problems at the same time by using a novel high-level Petri net, termed an Object-Oriented and Timed Predicate/Transition Net (OOTPr/Tr net. After defining the three seaside operational problems formally, we integrated them as a three-level framework that was further transformed into an OOTPr/Tr net model. Then, using the Prolog programming language, we implemented this model as a simulation tool to find the best solution based on the various combinations of heuristic rules used.

  17. Net Gains

    Science.gov (United States)

    Fielker, David

    2008-01-01

    The Easter conference 2008 had several activities which for the author raised the same questions on cube nets in some work with eight-year-olds some time ago. In this article, the author muses on some problems from the Easter conference regarding nets of shapes. (Contains 1 note.)

  18. Control of groundwater pH during bioremediation: Improvement and validation of a geochemical model to assess the buffering potential of ground silicate minerals

    Science.gov (United States)

    Lacroix, Elsa; Brovelli, Alessandro; Holliger, Christof; Barry, D. A.

    2014-05-01

    Accurate control of groundwater pH is of critical importance for in situ biological treatment of chlorinated solvents. The use of ground silicate minerals mixed with groundwater is an appealing buffering strategy as silicate minerals may act as long-term sources of alkalinity. In a previous study, we developed a geochemical model for evaluation of the pH buffering capacity of such minerals. The model included the main microbial processes driving groundwater acidification as well as mineral dissolution. In the present study, abiotic mineral dissolution experiments were conducted with five silicate minerals (andradite, diopside, fayalite, forsterite, nepheline). The goal of the study was to validate the model and to test the buffering capacity of the candidate minerals identified previously. These five minerals increased the pH from acidic to neutral and slightly basic values. The model was revised and improved to represent better the experimental observations. In particular, the experiments revealed the importance of secondary mineral precipitation on the buffering potential of silicates, a process not included in the original formulation. The main secondary phases likely to precipitate were identified through model calibration, as well as the degree of saturation at which they formed. The predictions of the revised geochemical model were in good agreement with the observations, with a correlation coefficient higher than 0.9 in most cases. This study confirmed the potential of silicates to act as pH control agents and showed the reliability of the geochemical model, which can be used as a design tool for field applications.

  19. Control of groundwater pH during bioremediation: improvement and validation of a geochemical model to assess the buffering potential of ground silicate minerals.

    Science.gov (United States)

    Lacroix, Elsa; Brovelli, Alessandro; Holliger, Christof; Barry, D A

    2014-05-01

    Accurate control of groundwater pH is of critical importance for in situ biological treatment of chlorinated solvents. The use of ground silicate minerals mixed with groundwater is an appealing buffering strategy as silicate minerals may act as long-term sources of alkalinity. In a previous study, we developed a geochemical model for evaluation of the pH buffering capacity of such minerals. The model included the main microbial processes driving groundwater acidification as well as mineral dissolution. In the present study, abiotic mineral dissolution experiments were conducted with five silicate minerals (andradite, diopside, fayalite, forsterite, nepheline). The goal of the study was to validate the model and to test the buffering capacity of the candidate minerals identified previously. These five minerals increased the pH from acidic to neutral and slightly basic values. The model was revised and improved to represent better the experimental observations. In particular, the experiments revealed the importance of secondary mineral precipitation on the buffering potential of silicates, a process not included in the original formulation. The main secondary phases likely to precipitate were identified through model calibration, as well as the degree of saturation at which they formed. The predictions of the revised geochemical model were in good agreement with the observations, with a correlation coefficient higher than 0.9 in most cases. This study confirmed the potential of silicates to act as pH control agents and showed the reliability of the geochemical model, which can be used as a design tool for field applications.

  20. Net primary productivity of China's terrestrial ecosystems from a process model driven by remote sensing.

    Science.gov (United States)

    Feng, X; Liu, G; Chen, J M; Chen, M; Liu, J; Ju, W M; Sun, R; Zhou, W

    2007-11-01

    The terrestrial carbon cycle is one of the foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, China's terrestrial NPP was simulated using the Boreal Ecosystem Productivity Simulator (BEPS), a carbon-water coupled process model based on remote sensing inputs. For these purposes, a national-wide database (including leaf area index, land cover, meteorology, vegetation and soil) at a 1 km resolution and a validation database were established. Using these databases and BEPS, daily maps of NPP for the entire China's landmass in 2001 were produced, and gross primary productivity (GPP) and autotrophic respiration (RA) were estimated. Using the simulated results, we explore temporal-spatial patterns of China's terrestrial NPP and the mechanisms of its responses to various environmental factors. The total NPP and mean NPP of China's landmass were 2.235 GtC and 235.2 gCm(-2)yr(-1), respectively; the total GPP and mean GPP were 4.418 GtC and 465 gCm(-2)yr(-1); and the total RA and mean RA were 2.227 GtC and 234 gCm(-2)yr(-1), respectively. On average, NPP was 50.6% of GPP. In addition, statistical analysis of NPP of different land cover types was conducted, and spatiotemporal patterns of NPP were investigated. The response of NPP to changes in some key factors such as LAI, precipitation, temperature, solar radiation, VPD and AWC are evaluated and discussed.

  1. Modeling and performance analysis of a closed-loop supply chain using first-order hybrid Petri nets

    Directory of Open Access Journals (Sweden)

    Imane Outmal

    2016-05-01

    Full Text Available Green or closed-loop supply chain had been the focus of many manufacturers during the last decade. The application of closed-loop supply chain in today’s manufacturing is not only due to growing environmental concerns and the recognition of its benefits in reducing greenhouse gas emissions, energy consumption, and meeting a more strict environmental regulations but it also offers economic competitive advantages if appropriately managed. First-order hybrid Petri nets represent a powerful graphical and mathematical formalism to map and analyze the dynamics of complex systems such as closed-loop supply chain networks. This article aims at illustrating the use of first-order hybrid Petri nets to model a closed-loop supply chain network and evaluate its operational, financial, and environmental performance measures under different management policies. Actual data from auto manufacturer in the United States are used to validate network’s performance under both tactical and strategic decision-making, namely, (1 tactical decision—production policies: increase of recovered versus new components and (2 strategic decision—closed-loop supply chain network structure: manufacturer internal recovery process or recovery process done by a third-party collection and recovery center. The work presented in this article is an extension of the use of first-order hybrid Petri nets as a modeling and performance analysis tool from supply chain to closed-loop supply chain. The modularity property of first-order hybrid Petri nets has been used in the modeling process, and the simulation and analysis of the modeled network are done in MATLAB® environment. The results of the experiments depict that first-order hybrid Petri nets are a powerful modeling and analysis formalism for closed-loop supply chain networks and can be further used as an efficient decision-making tool at both tactical and strategic levels. Unlike other researches on modeling supply chain

  2. Protein-protein interaction network construction for cancer using a new L1/2-penalized Net-SVM model.

    Science.gov (United States)

    Chai, H; Huang, H H; Jiang, H K; Liang, Y; Xia, L Y

    2016-07-25

    Identifying biomarker genes and characterizing interaction pathways with high-dimensional and low-sample size microarray data is a major challenge in computational biology. In this field, the construction of protein-protein interaction (PPI) networks using disease-related selected genes has garnered much attention. Support vector machines (SVMs) are commonly used to classify patients, and a number of useful tools such as lasso, elastic net, SCAD, or other regularization methods can be combined with SVM models to select genes that are related to a disease. In the current study, we propose a new Net-SVM model that is different from other SVM models as it is combined with L1/2-norm regularization, which has good performance with high-dimensional and low-sample size microarray data for cancer classification, gene selection, and PPI network construction. Both simulation studies and real data experiments demonstrated that our proposed method outperformed other regularization methods such as lasso, SCAD, and elastic net. In conclusion, our model may help to select fewer but more relevant genes, and can be used to construct simple and informative PPI networks that are highly relevant to cancer.

  3. Modeling the effect of physiological responses to green pruning on net biomass production of Eucalyptus nitens.

    Science.gov (United States)

    Pinkard, E. A.; Battaglia, M.; Beadle, C. L.; Sands, P. J.

    1999-01-01

    Green pruning of Eucalyptus nitens (Deane and Maiden) Maiden increases instantaneous rates of light-saturated CO(2) assimilation (A), and changes patterns of total leaf area and foliage distribution. We investigated the importance of such changes on the rate of recovery of growth following pruning. A simple process-based model was developed to estimate daily net biomass production (G(d)) of three-year-old plantation-grown trees over a 20-month period. The trees had been pruned by removal of 0, 50 or 70% of the length of green crown, equivalent to removal of 0, 55 or 88% of leaf area, respectively, when the plantation verged on canopy closure. Total G(d) was reduced by only 20% immediately following the 50%-pruning treatment, as a result of both the high leaf dark respiration and low A in the portion of the crown removed compared to the top of the crown. Pruning at the time of canopy closure preempted a natural and rapid decline in G(d) of the lower crown. Although leaf area index (L) was approximately 6.0 at the time of pruning, high light interception (95%) occurred with an L of 4.0. The 50%-pruning treatment reduced L to 3.5, but the physiological responses to pruning were sufficient to compensate fully for the reduction in intercepted radiation within 110 days of pruning. The 70%-pruning treatment reduced L to 1.9, and reduced G(d) by 77%, reflecting the removal of branches with high A in the mid and upper crown. Physiological responses to the 70%-pruning treatment were insufficient to increase G(d) to the value of unpruned trees during the study. Model sensitivity analysis showed that increases in A following pruning increased G(d) by 20 and 25% in the 50- and 70%-pruned trees, respectively, 20 months after pruning. Changes in leaf area/foliage distribution had a greater effect on G(d) of 50%-pruned trees (47% increase) than did changes in A. However, the reduction in photosynthetic potential associated with the 70%-pruning treatment resulted in only small

  4. Porosity Development in a Coastal Setting: A Reactive Transport Model to Assess the Influence of Heterogeneity of Hydrological, Geochemical and Lithological Conditions

    Science.gov (United States)

    Maqueda, A.; Renard, P.; Cornaton, F. J.

    2014-12-01

    Coastal karst networks are formed by mineral dissolution, mainly calcite, in the freshwater-saltwater mixing zone. The problem has been approached first by studying the kinetics of calcite dissolution and then coupling ion-pairing software with flow and mass transport models. Porosity development models require high computational power. A workaround to reduce computational complexity is to assume the calcite dissolution reaction is relatively fast, thus equilibrium chemistry can be used to model it (Sanford & Konikow, 1989). Later developments allowed the full coupling of kinetics and transport in a model. However kinetics effects of calcite dissolution were found negligible under the single set of assumed hydrological and geochemical boundary conditions. A model is implemented with the coupling of FeFlow software as the flow & transport module and PHREEQC4FEFLOW (Wissmeier, 2013) ion-pairing module. The model is used to assess the influence of heterogeneities in hydrological, geochemical and lithological boundary conditions on porosity evolution. The hydrologic conditions present in the karst aquifer of Quintana Roo coast in Mexico are used as a guide for generating inputs for simulations.

  5. A Web-Based Electronic Book (e-book) Library: The netLibrary Model.

    Science.gov (United States)

    Connaway, Lynn Silipigni

    2001-01-01

    Identifies elements that are important for academic libraries to use in evaluating electronic books, including content; acquisition and collection development; software and hardware standards and protocols; digital rights management; access; archiving; privacy; the market and pricing; and enhancements and ideal features. Describes netLibrary, a…

  6. A Web-Based Electronic Book (e-book) Library: The netLibrary Model.

    Science.gov (United States)

    Connaway, Lynn Silipigni

    2001-01-01

    Identifies elements that are important for academic libraries to use in evaluating electronic books, including content; acquisition and collection development; software and hardware standards and protocols; digital rights management; access; archiving; privacy; the market and pricing; and enhancements and ideal features. Describes netLibrary, a…

  7. Fluid-Dacite Interaction in the PACMANUS Subseafloor Hydrothermal System - Preliminary Results From Secondary Mineral Chemistry and Geochemical Modeling

    Science.gov (United States)

    Yeats, C. J.; Bach, W.; Vanko, D. A.; Roberts, S.; Lackschewitz, K.; Paulick, H.

    2001-12-01

    During Ocean Drilling Program Leg 193, several holes (as deep as 386 meters below sea floor) intersected variably altered and veined dacites on Pual Ridge in the eastern Manus back-arc basin. The hydothermal alteration is complex and multi-stage, and includes pervasive alteration and alteration halos along anhydrite±pyrite±quartz veins. Our preliminary interpretation is that an early pervasive "chloritic" alteration (chlorite, chlorite/smectite, quartz, +/-albite, +/-magnetite) is overprinted locally by illite-pyrophyllite-anhydrite+/-diaspore alteration followed by silica (quartz and cristobalite) flooding. Two drill holes at Snowcap, a site of diffuse venting, reveal alteration profiles of strongly illite-pyrophyllite-anhydrite altered rocks in the shallow parts grading downwards into rocks that show dominant chloritic alteration. At Roman Ruins, a site of discrete venting, K-feldspar and illite-smectite mixed layer phases are abundant and magnetite is rare. K-feldspar appears to be part of the "chloritic" alteration assemblage. Anhydrite is locally abundant but generally less common than at Snowcap. There is a strong lateral heterogeneity in basement alteration as revealed by the differences between sites in the depths of cristobalite-quartz transition and the zones of prevailing alteration styles. Geochemical modeling suggests that the rocks have been altered at temperatures of about 250 to 300° C under variable fluid-to-rock ratios. While all the mineral assemblages are consistent with quartz/cristobalite saturation of the fluids, the formation of diaspore must be related to episodic interaction of the rocks with fluids highly undersaturated in quartz. The early stage of chloritic alteration represents interaction of the dacites with fluids of a fairly high pH ({>}4). In contrast, the occurrence of pyrophyllite and local diaspore suggests lower pH fluid ({hydrothermal stages. A zone of abundant alunite at 350 m deep in the basement at Snowcap may represent

  8. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps, to...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  9. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps, to...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  10. Petri Nets and Semantics of System Descriptions

    DEFF Research Database (Denmark)

    Jensen, Kurt; Kyng, Morten

    1982-01-01

    This paper discusses the use of Petri nets as a semantic tool in the design of languages and in the construction and analysis of system descriptions. The topics treated are: Languages based on nets. The problem of time in nets. Nets and related models. Nets and formal semantics. Parallel program...

  11. Petroleum generation and migration in the Berkine (Ghadames) Basin, Eastern Algeria. An organic geochemical and basin modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Yahi, N.

    1999-07-01

    In this study the petroleum system of one of the most important hydrocarbon bearing basins in Algeria, the Berkine Basin, was reconstructed by combining the geological knowledge of the basin and the results of geochemical and basin modelling studies. In this order, total organic carbon (C{sub org}) measurements, Rock-Eval pyrolyses, vitrinite reflectance measurements, gas chromatography (GC) analyses as well as gas chromatography-mass spectrometry (GC-MS) analyses were performed in order to evaluate the source rocks with respect to organic richness, kerogen type, depositional environment and maturity. Following the previous evaluation, the burial, erosion and temperature developments within the basin were reconstructed applying both one-dimensional (PDI/1D) and two-dimensional (PetroMod/2D) basin modelling programs. The hydrocarbon generation history of two major Palaeozoic source rocks was reconstructed based on the predetermined temperature history and kinetic model for hydrocarbon (oil and gas) generation. The basin has the benefit of multiple hydrocarbon sources deposited duirng the Silurian and the Frasnian periods within a continental shelf environment. The development of anoxic to dysoxic bottom water conditions was a prerequisite for the deposition of these organic rich units. While increasing the commercial value of the basin by increasing the hydrocarbon potential, these source rocks by generating hydrocarbons at different epochs during the basin evolution generally complicate the understanding of the petroleum system and the oil and gas accumulations. Therefore, the 2D finite element program PetroMod was used to discuss the history of hydrocarbon generation, expulsion and accumulation along a 205 km long selected transect which crosses various oil and gas fields. The major goal was to understand these hydrocarbon accumulations of which the origin and emplacement are still unsolved up to date. The understanding of such important petroleum geology aspects

  12. Reaction of Topopah Spring tuff with J-13 water: a geochemical modeling approach using the EQ3/6 reaction path code

    Energy Technology Data Exchange (ETDEWEB)

    Delany, J.M.

    1985-11-25

    EQ3/6 geochemical modeling code package was used to investigate the interaction of the Topopah Spring Tuff and J-13 water at high temperatures. EQ3/6 input parameters were obtained from the results of laboratory experiments using USW G-1 core and J-13 water. Laboratory experiments were run at 150 and 250{sup 0}C for 66 days using both wafer-size and crushed tuff. EQ3/6 modeling reproduced results of the 150{sup 0}C experiments except for a small increase in the concentration of potassium that occurs in the first few days of the experiments. At 250{sup 0}C, the EQ3/6 modeling reproduced the major water/rock reactions except for a small increase in potassium, similar to that noted above, and an overall increase in aluminum. The increase in potassium concentration cannot be explained at this time, but the increase in A1 concentration is believed to be caused by the lack of thermodynamic data in the EQ3/6 data base for dachiardite, a zeolite observed as a run product at 250{sup 0}C. The ability to reproduce the majority of the experimental rock/water interactions at 150{sup 0}C validates the use of EQ3/6 as a geochemical modeling tool that can be used to theoretically investigate physical/chemical environments in support of the Waste Package Task of NNWSI.

  13. An ice-ocean model study to explore climate change mechanisms in comparison with interannual-to-decadal variability of geochemical tracers

    Institute of Scientific and Technical Information of China (English)

    Motoyoshi Ikeda

    2014-01-01

    One way to identify the mechanisms that are crucial to Arctic climate change is to use existing data that exhibit interannual-to-decadal variability in the sea ice and ocean interior due to atmospheric forcing. Since around 1960s, valuable geochemical data of the ocean interior, together with atmospheric and sea ice data, have been analyzed and examined in a coupled ice–ocean model with an idealized configuration of the Arctic Basin. This is fundamentally driven by negative salt flux, in addition to atmospheric circulation and cooling. This strategy has a clear advantage over more sophisticated models with higher resolution that require extensive data collections for veriifcation. Around 1990, the dominant atmospheric mode shifted from the Northern Annular Mode (NAM) to the Arctic Dipole Mode (ADM). The variability of sea ice cover was explained by these two modes sequentially and reproduced in the model. In particular, the geochemical ifelds indicated a movement of the Transpolar Drift Stream due to the NAM and an oscillation of the Paciifc water between the Atlantic and Paciifc sides due to the ADM. Both these features were reproduced reasonably well by the oceanic tracers in the model, including the time lags of about one third of the oscillation periods. Thus, this strategy can suggest methods and locations for monitoring oceanographic responses to Arctic climate change.

  14. An Exploratory Analysis of the .Net Component Model and Uniframe Paradigm Using a Collaborative Approach

    Science.gov (United States)

    2004-08-01

    84 disparate platforms. An organization with numerous applications needs EAI solution and corporations that are extending their processes with...attempts a retry for a certain value nretry and even if the communicatin fails, the LM is marked as dead by removing it from its list of known LMs and...MIC01a] Obermeyer, P. and J. Hawkins, Microsoft Corporation , “Microsoft .NET Remoting – A Technical Overview,” Official MSDN Website, 2001, http

  15. Development of a New Zealand SedNet model for assessment of catchment-wide soil-conservation works

    Science.gov (United States)

    Dymond, John R.; Herzig, Alexander; Basher, Les; Betts, Harley D.; Marden, Mike; Phillips, Chris J.; Ausseil, Anne-Gaelle E.; Palmer, David J.; Clark, Maree; Roygard, Jon

    2016-03-01

    Much hill country in New Zealand has been converted from indigenous forest to pastoral agriculture, resulting in increased soil erosion. Following a severe storm that hit the Manawatu-Wanaganui region in 2004 and caused 62,000 landslides, the Horizons Regional Council have implemented the Sustainable Land Use Initiative (SLUI), a programme of widespread soil conservation. We have developed a New Zealand version (SedNetNZ) of the Australian SedNet model to evaluate the impact of the SLUI programme in the 5850 km2 Manawatu catchment. SedNetNZ spatially distributes budgets of fine sediment in the landscape. It incorporates landslide, gully, earthflow erosion, surficial erosion, bank erosion, and flood-plain deposition, the important forms of soil erosion in New Zealand. Modelled suspended sediment loads compared well with measured suspended sediment loads with an R2 value of 0.85 after log transformation. A sensitivity analysis gave the uncertainty of estimated suspended sediment loads to be approximately plus or minus 50% (at the 95% confidence level). It is expected that by 2040, suspended sediment loads in targeted water management zones will decrease by about 40%. The expected decrease for the whole catchment is 34%. The expected reduction is due to maturity of tree planting on land at risk to soil erosion. The 34% reduction represents an annual rate of return of 20% on 20 million NZ of investment on soil conservation works through avoided damage to property and infrastructure and avoided clean-up costs.

  16. [Prediction model of net photosynthetic rate of ginseng under forest based on optimized parameters support vector machine].

    Science.gov (United States)

    Wu, Hai-wei; Yu, Hai-ye; Zhang, Lei

    2011-05-01

    Using K-fold cross validation method and two support vector machine functions, four kernel functions, grid-search, genetic algorithm and particle swarm optimization, the authors constructed the support vector machine model of the best penalty parameter c and the best correlation coefficient. Using information granulation technology, the authors constructed P particle and epsilon particle about those factors affecting net photosynthetic rate, and reduced these dimensions of the determinant. P particle includes the percent of visible spectrum ingredients. Epsilon particle includes leaf temperature, scattering radiation, air temperature, and so on. It is possible to obtain the best correlation coefficient among photosynthetic effective radiation, visible spectrum and individual net photosynthetic rate by this technology. The authors constructed the training set and the forecasting set including photosynthetic effective radiation, P particle and epsilon particle. The result shows that epsilon-SVR-RBF-genetic algorithm model, nu-SVR-linear-grid-search model and nu-SVR-RBF-genetic algorithm model obtain the correlation coefficient of up to 97% about the forecasting set including photosynthetic effective radiation and P particle. The penalty parameter c of nu-SVR-linear-grid-search model is the minimum, so the model's generalization ability is the best. The authors forecasted the forecasting set including photosynthetic effective radiation, P particle and epsilon particle by the model, and the correlation coefficient is up to 96%.

  17. Net ecosystem CO2 exchange and evapotranspiration of a sphagnum mire: field measurements and model simulations

    Science.gov (United States)

    Olchev, Alexander; Volkova, Elena; Karataeva, Tatiana; Zatsarinnaya, Dina; Novenko, Elena

    2014-05-01

    The spatial and temporal variability of net ecosystem exchange of CO2 (NEE) and evapotranspiration (ET) of a karst-hole sphagnum peat mire situated at the boundary between broad-leaved and forest-steppe zones in the central part of European Russia (54.06N, 37.59E, 260 m a.s.l.) was described using results of field measurements and simulations with Mixfor-3D model. The area of the mire is about 1.2 ha and it is surrounded by a broadleaved forest stand. It is a typical peat mire according to water and mineral supply as well as to vegetation composition. The vegetation of the peripheral parts of the mire is typical eutrophic whereas the vegetation in its central part is represented by meso-oligothrophic plant communities. To describe the spatial variability of NEE and ET within the mire a portable measuring system consisting of a transparent ventilated chamber combined with an infrared CO2 and H2O analyzer LI-840A (Li-Cor, USA) was used. The measurements were provided along a transect from the southern peripheral part of the mire to its center under sunny clear-sky weather conditions in the period from May to September of 2012 and from May 2013 to October 2013. The chamber method was used for measurements of NEE and ET fluxes because of small size of the mire, a very uniform surrounding forest stand and the mosaic mire vegetation. All these factors promote very heterogeneous exchange conditions within the mire and make it difficult to apply, for example, an eddy covariance method that is widely used for flux measurements in the field. The results of the field measurements showed a significant spatial and temporal variability of NEE and ET that was mainly influenced by incoming solar radiation, air temperature and ground water level. During the entire growing season the central part of the mire was a sink of CO2 for the atmosphere (up to 6.8±4.2 µmol m-2 s-1 in June) whereas its peripheral part, due to strong shading by the surrounding forest, was mainly a source of

  18. Decoding recent mud-volcano activity in the westernmost Mediterranean: Evidence from sediment/porewater data and geochemical modeling

    Science.gov (United States)

    López-Rodríguez, Carmina; Martínez-Ruíz, Francisca; Mogollón, José M.; Comas, Menchu; Nieto, Fernando; Böning, Philipp; Pahnke, Katharina; Sapart, Célia; De Lange, Gert J.

    2017-04-01

    Recent studies have demonstrated the occurrence of active mud volcanism in the West Alboran Basin. Though most of the mud volcanoes (MVs) discovered in this region are dormant, a few structures evidence active hydrocarbon venting, as Carmen MV. This study focuses on sedimentological and geochemical investigations on one piston core, GP05PC, recovered from the summit of Carmen MV during the Gasalb-Pelagia cruise (2011). Although the full core consists of mud breccia sediments, a dramatic change occurs between enhanced methane concentrations in its lowermost and dissolved SO42- in its uppermost sediments. At the boundary of 150 cm, methane is oxidized and sulphate reduced. In the lowermost interval, the depletion of major elements (i.e., Ca2+ and Mg2+), the enrichment of trace species (i.e., Li+ and B) and the radiogenic 87Sr all point to a deep fluid source. The δ18Opw and δDpw compositions of pore water (5.7‰ and -10‰ VSMOW, respectively) together with the mineralogical results (presence of randomly insterstrafied (R0) illite-smectite minerals (I/S) to more illitic (>50% I) and ordered ones (R1-R3)) indicate smectite to illite transformation at greater depth and support smectite dehydration as the main porewater freshening mechanism. Water formation temperatures calculated through the application of empirical geo-thermometers (K-Na, K-Mg and K-Ca) together with the presence from I/S mixed layers (R3) suggest that fluids were generated at temperatures 100-200°C. This temperature indicates that, under a regional geothermal gradient, the fluid source originates from 8 km depth. From an adjacent borehole it is known that sedimentary units of Early to Middle Miocene age occur at that depth (Jurado and Comas et al., 1992). The δ13Cmethane and δDmethane composition of methane (-59‰ VPDB and -184‰ VSMOW, respectively) of the deepest sample also may be associated to a thermogenic origin. The absence of hemipelagic sediment draping, the distinctive seawater

  19. Modelling Effects of Water Table Depth Variations on Net Ecosystem CO2 Exchange of a Western Canadian Peatland

    Science.gov (United States)

    Mezbahuddin, S.; Grant, R. F.; Flanagan, L. B.

    2014-12-01

    Water table depth (WTD) is one of the key drivers affecting aggradation and degradation of peatlands. Variations in WTD can alter the balance between gross primary productivity (GPP) and ecosystem respiration (Re) and so cause a peatland to change between a sink and a source of carbon. Process based mathematical modelling can provide insights on WTD-net ecosystem productivity (NEP) interactions over peatlands. We deployed a process-based ecosystem model ecosys to examine the WTD effects on variations in NEP of a fen peatland in Alberta, Canada. Our modelled results showed that a growing season (May-August) WTD drawdown of ~0.3m from 2004-2007 caused more rapid decomposition in deeper peat layers so that Re increased by ~180 g C m-2 growing season -1. However, similar increase in GPP (~ 170 g C m-2 growing season -1) under deeper WTD condition due to more rapid microbial and root growth, and hence more rapid mineralization and nutrient uptake, left no net effect of WTD drawdown on NEP. The modelled ecosystem was overall a large sink of C (~ 100 g C m-2 yr-1) over the study period of 2004-2009. However, gradually diminishing GPP by ~ 70 g C m-2 growing season -1 with progressively deeper WTD during 2008-2009 indicated that further drawdown of WTD could alter the source sink status of these peatlands. These modelled results were corroborated against hourly eddy covariance (EC) net CO2 fluxes, latent heat and sensible heat fluxes (R2~0.75, a→0, b→1); and annual estimates of EC-gap filled NEP and partitioned GPP and Re over the site from 2004-2009. Our findings indicated the needs for coupling of soil-plant-atmosphere schemes for gases, water, energy, carbon and nutrients in models to adequately simulate WTD effects on peatland C stocks.

  20. FILTER-NET STRUCTURE AND PUMPING ACTIVITY IN THE POLYCHAETE NEREIS-DIVERSICOLOR - EFFECTS OF TEMPERATURE AND PUMP-MODELING

    DEFF Research Database (Denmark)

    Riisgård, H.U.; Vedel, A.; Boye, H.

    1992-01-01

    and a halving of the net cycle length. At low temperatures a tendency towards an extended pause between pumping periods was noticed. The N. diversicolor pump was modelled as a positive displacement leaking unit, and earlier data on back pressure characteristics were examined in light of the proposed model....... diversicolor muscular positive displacement pump (unlike for viscous ciliary pumps)....... on water processing were measured as clearance of suspended algal cells or measured directly. Pumping activity (undulating body movements of worms kept in glass tubes) was monitored using an infrared phototransducer technique. In the temperature interval from 5 to about 15-degrees-C there was a linear...

  1. The applicability and limitations of the geochemical models and tools used in simulating radionuclide behaviour in natural waters. Lessons learned from the Blind Predictive Modelling exercises performed in conjunction with Natural Analogue studies

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Duro, L.; Grive, M. [QuantiSci SL, Parc Tecnologic del Valles (Spain)

    2001-07-01

    One of the key applications of Natural Analogue studies to the Performance Assessment (PA) of nuclear waste disposal has been the possibility to test the geochemical models and tools to be used in describing the migration of radionuclides in a future radioactive waste repository system. To this end, several geochemical modelling testing exercises (commonly denoted as Blind Predictive Modelling), have formed an integral part of Natural Analogue Studies over the last decade. Consequently, we thought that this is a timely occasion to make an evaluation of the experience gained and lessons learnt. We have reviewed, discussed and compared the results obtained from the Blind Prediction Modelling (BPM) exercises carried out within 7 Natural Analogue Studies: Oman, Pocos de Caldas, Cigar Lake, Maqarin, El Berrocal, Oklo and Palmottu. To make this comparison meaningful, we present the main geochemical characteristics of each site in order to highlight the most relevant mineralogical and hydrochemical differences. From the complete list of elements studied at all the investigated sites we have made a selection based on the relevance of a given element from a PA viewpoint and on the frequency this element has been included in the BPM exercises. The elements selected for discussion are: Sr, Ba, Sn, Pb, Se, Ni, Zn, REEs, Th and U. We have based our discussion on the results obtained from the speciation as well as solubility calculations. From the comparison of the results it is concluded that we can differentiate between three element categories: 1. Elements whose geochemical behaviour can be fairly well described by assuming solubility control exerted by pure solid phases of the given element (i.e. Th, U under reducing conditions and U in some sites under oxidising conditions); 2. Elements for which the association to major geochemical components of the system must be considered in order to explain their concentrations in groundwaters (i.e. Sr, Ba, Zn, Se, REEs and U under

  2. Autonomy-subnet based structural synthesis and liveness guarantying policy of Petri net model of flexible manufacturing system

    Institute of Scientific and Technical Information of China (English)

    XUE Lei; HAO Yue

    2004-01-01

    In this paper, an autonomous subnet based structural methodology for bottom-up synthesis of Petri Nets for Flexible Manufacturing Systems is proposed. Furthermore, the theoretical analysis of the model constructed by the method is carried by intensively using model's structural information, such as invariants, siphons, etc.. As a result, the analysis leads us to draw the general conclusion that the model obtained is conservativeness and thus bound, and characterize its liveness in terms of zero-marking minimal siphons. It is based on model's structural information that distinguishes our method from others. In line of this thought, a liveness guarantying policy for the obtained model is proposed. Some control subnets are merged into the original model according to the proposed synthesis rules in this paper to ensure that no minimal siphons are emptied in any state, therefore the liveness is guaranteed. As a result, a live, conservative and revertible Petri Nets is obtained. A practical example is also presented to demonstrate the effectiveness of this method.

  3. Development of a numerical model for fluid-structure interaction analysis of flow through and around an aquaculture net cage

    DEFF Research Database (Denmark)

    Chen, Hao; Christensen, Erik Damgaard

    2017-01-01

    In the present work, we developed a numerical model for fluid-structure interaction analysis of flow through and around an aquaculture net cage. The numerical model is based on the coupling between the porous media model and the lumped mass structural model. A novel interface was implemented...... was approximated by a set of dynamic porous zones, where the grid cells were updated at every iteration based on the transferred nodal positions from the structural model. A time stepping procedure was introduced, so the solver is applicable in both steady and unsteady conditions. In order to reduce...... the computational effort, sub-cycling was applied for the structural solver within each time step, based on the quasi-steady state assumption. The numerical model was validated against experiments in both steady and unsteady conditions. In general, the agreement is satisfactory....

  4. RESTful NET

    CERN Document Server

    Flanders, Jon

    2008-01-01

    RESTful .NET is the first book that teaches Windows developers to build RESTful web services using the latest Microsoft tools. Written by Windows Communication Foundation (WFC) expert Jon Flanders, this hands-on tutorial demonstrates how you can use WCF and other components of the .NET 3.5 Framework to build, deploy and use REST-based web services in a variety of application scenarios. RESTful architecture offers a simpler approach to building web services than SOAP, SOA, and the cumbersome WS- stack. And WCF has proven to be a flexible technology for building distributed systems not necessa

  5. Targeting Neuroblastoma Cell Surface Proteins: Recommendations for Homology Modeling of hNET, ALK, and TrkB

    Science.gov (United States)

    Haddad, Yazan; Heger, Zbyněk; Adam, Vojtech

    2017-01-01

    Targeted therapy is a promising approach for treatment of neuroblastoma as evident from the large number of targeting agents employed in clinical practice today. In the absence of known crystal structures, researchers rely on homology modeling to construct template-based theoretical structures for drug design and testing. Here, we discuss three candidate cell surface proteins that are suitable for homology modeling: human norepinephrine transporter (hNET), anaplastic lymphoma kinase (ALK), and neurotrophic tyrosine kinase receptor 2 (NTRK2 or TrkB). When choosing templates, both sequence identity and structure quality are important for homology modeling and pose the first of many challenges in the modeling process. Homology modeling of hNET can be improved using template models of dopamine and serotonin transporters instead of the leucine transporter (LeuT). The extracellular domains of ALK and TrkB are yet to be exploited by homology modeling. There are several idiosyncrasies that require direct attention throughout the process of model construction, evaluation and refinement. Shifts/gaps in the alignment between the template and target, backbone outliers and side-chain rotamer outliers are among the main sources of physical errors in the structures. Low-conserved regions can be refined with loop modeling method. Residue hydrophobicity, accessibility to bound metals or glycosylation can aid in model refinement. We recommend resolving these idiosyncrasies as part of “good modeling practice” to obtain highest quality model. Decreasing physical errors in protein structures plays major role in the development of targeting agents and understanding of chemical interactions at the molecular level. PMID:28163672

  6. Targeting Neuroblastoma Cell Surface Proteins: Recommendations for Homology Modeling of hNET, ALK, and TrkB.

    Science.gov (United States)

    Haddad, Yazan; Heger, Zbyněk; Adam, Vojtech

    2017-01-01

    Targeted therapy is a promising approach for treatment of neuroblastoma as evident from the large number of targeting agents employed in clinical practice today. In the absence of known crystal structures, researchers rely on homology modeling to construct template-based theoretical structures for drug design and testing. Here, we discuss three candidate cell surface proteins that are suitable for homology modeling: human norepinephrine transporter (hNET), anaplastic lymphoma kinase (ALK), and neurotrophic tyrosine kinase receptor 2 (NTRK2 or TrkB). When choosing templates, both sequence identity and structure quality are important for homology modeling and pose the first of many challenges in the modeling process. Homology modeling of hNET can be improved using template models of dopamine and serotonin transporters instead of the leucine transporter (LeuT). The extracellular domains of ALK and TrkB are yet to be exploited by homology modeling. There are several idiosyncrasies that require direct attention throughout the process of model construction, evaluation and refinement. Shifts/gaps in the alignment between the template and target, backbone outliers and side-chain rotamer outliers are among the main sources of physical errors in the structures. Low-conserved regions can be refined with loop modeling method. Residue hydrophobicity, accessibility to bound metals or glycosylation can aid in model refinement. We recommend resolving these idiosyncrasies as part of "good modeling practice" to obtain highest quality model. Decreasing physical errors in protein structures plays major role in the development of targeting agents and understanding of chemical interactions at the molecular level.

  7. IRETHERM: Developing a Strategic and Holistic Understanding of Ireland's Geothermal Energy Potential through Integrated Modelling of New and Existing Geophysical, Geochemical and Geological Data

    Science.gov (United States)

    Jones, Alan G.; Daly, Stephen; Vozar, Jan; Rath, Volker; Campanya, Joan; Blake, Sarah; Delhaye, Robert; Fritschle, Tobias; Willmot Noller, Nicola; Long, Mike; Waters, Tim

    2015-04-01

    The Science Foundation Ireland funded academia-government-industry collaborative IRETHERM project (www.iretherm.ie), initiated in 2011, is developing a strategic understanding of Ireland's (all-island) deep geothermal energy potential through integrated modelling of new and existing geophysical, geochemical and geological data. Potential applications include both low enthalpy district space heating of large urban centres and electricity generation from intermediate-temperature waters. IRETHERM comprises three broad geothermal target types; 1) Assessment of the geothermal energy potential of Ireland's radiogenic granites (EGS), (2) Assessment of the geothermal energy potential of Ireland's deep sedimentary basins (HSA), and, (3) Assessment of the geothermal energy potential of warm springs. The geophysical subsurface imaging techniques of choice are controlled-source (CSEM) and natural-source (magnetotellurics, MT) electromagnetic methods. Electrical conductivity, being a transport property, is a proxy for permeability, and appropriate porosity-permeability relations are being developed. To date, MT measurements have been made at 466 sites over sedimentary basins (190 sites), granites (156 sites) and warm springs (120 sites), with CSEM across one warm spring. An ongoing continuous geochemical (temperature and electrical conductivity every 15 mins) and time-lapse seasonal hydrochemical sampling programmes are in progress at six warm spring sites. A database on heat production in Irish rocks has been compiled, of more than 3,300 geochemical sample measurements, with 3,000 retrieved from various archives and over 300 new analyses. Geochemistry, geochronology and isotopic analyses have been conducted on subsurface granites and exposed analogues astride the Iapetus Suture Zone in order to understand the underlying reasons for their radiogenic heat production. Finally, thermal conductivity measurements have been made on borehole samples from representative lithologies

  8. Geochemical Origin of Biological Molecules

    Science.gov (United States)

    Bassez, Marie-Paule

    2013-04-01

    Conference and abstract in OLEB, 2008, 39 (3-4) 223. BASSEZ M.P. 2009 Prebiotic synthesis under hydothermal conditions, C. R. Chimie, Académie des Sciences, Paris 12 (6-7) : 801-807. BASSEZ M.P. 2012 A model for a geochemical origin of life in preparation BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009a Organic analysis of peridotite rocks from Ashadze and Logatchev hydrothermal sites, Int. J. Mol. Sci. 10(7): 2986-2998. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009b Organic analysis of peridotite rocks from the MAR, AGU fall meeting, P43C-1441, San Francisco, 14-18/12/2009. BASSEZ M.P., TAKANO Y. 2010a Prebiotic organic globules, Nature Precedings: Posted 21 Jul http://hdl:10101/npre.2010.4694.1. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2010b Organic analysis of peridotite rocks, First chemical steps towards the Origin of Life colloquium, Turin 16-17/09/2010. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011a A search for prebiotic molecular signatures inside rocks, Geobiology in Space exploration workshop, P sans n°, Marrakech 07-14/02/2011. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011b Detection of molecular biosignatures inside rocks, Origins 2011 ISSOL and Bioastronomy conference, P2-17, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y., 2011c Organic microstructures, Origins 2011 ISSOL and Bioastronomy conference, P2-34, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y. KOBAYASHI K. 2011d Prebiotic organic microstructures, Nature Precedings: Posted 14 Nov. http://hdl.handle.net/10101/npre.2011.4694.2 BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012a Prebiotic organic microstructures, Origin of Life Gordon Research Conference P4, Galveston, 08-13/01/2012. BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012b Prebiotic organic microstructures, Orig. Life Evol. Biosph. 42 (4) : 307-316.

  9. The geochemical reactions resulting from CO{sub 2} injection into the Midale Formation, Weyburn oilfield : a laboratory experimental and modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Azaroual, M.; Durst, P.; Czernichowski-Lauriol, I. [Bureau de Recherches Geologiques et Minieres, Orleans (France); Olsen, D.; Stentoft, N.; Springer, N. [Geological Survey of Denmark and Greenland (Denmark); Rochelle, C.A.; Pearce, J.; Bateman, K.; Birchall, D. [British Geological Survey, Nottingham (United Kingdom)

    2005-07-01

    One aspect of the International Energy Agency's (IEA) Weyburn CO2 Monitoring and Storage Project is the identification of geochemical changes that occur following the injection of carbon dioxide (CO{sub 2}) into the Midale Formation of the Weyburn Field in southern Saskatchewan. This paper summarized the fluid chemical and mineralogical changes noted during laboratory experiments on Midale core from the Weyburn Field. The reactions between injected CO{sub 2}, Midale lithologies and porewaters under temperatures and pressures representative of in-situ conditions were explored. The laboratory studies involved closed system batch experiments reacting samples of Midale reservoir rocks and cap rock with synthetic saline reservoir porewaters. Flow experiments were also performed based on both core flood approaches and column experiments. The duration of experiments ranged from 1 week to 6 months. Changes in fluid chemistry, mineralogy, porosity and permeability were measured. The results were then used to verify predictions from geochemical modelling activities. Experimental and theoretical studies of the effects of CO{sub 2} injection into the Midale lithologies showed variable amounts of carbonate mineral dissolution, some precipitation of gypsum, inhibition of anhydrite dissolution, and slow reactivity of alumino-silicate minerals. These indications helped develop an hypothesis and approaches to simulate the long term evolution of a one dimensional model representing CO{sub 2} injection into the host Midale Marly formation. . 3 refs., 4 figs.

  10. Grassland and cropland net ecosystem production of the U.S. Great Plains: Regression tree model development and comparative analysis

    Science.gov (United States)

    Wylie, Bruce K.; Howard, Daniel; Dahal, Devendra; Gilmanov, Tagir; Ji, Lei; Zhang, Li; Smith, Kelcy

    2016-01-01

    This paper presents the methodology and results of two ecological-based net ecosystem production (NEP) regression tree models capable of up scaling measurements made at various flux tower sites throughout the U.S. Great Plains. Separate grassland and cropland NEP regression tree models were trained using various remote sensing data and other biogeophysical data, along with 15 flux towers contributing to the grassland model and 15 flux towers for the cropland model. The models yielded weekly mean daily grassland and cropland NEP maps of the U.S. Great Plains at 250 m resolution for 2000–2008. The grassland and cropland NEP maps were spatially summarized and statistically compared. The results of this study indicate that grassland and cropland ecosystems generally performed as weak net carbon (C) sinks, absorbing more C from the atmosphere than they released from 2000 to 2008. Grasslands demonstrated higher carbon sink potential (139 g C·m−2·year−1) than non-irrigated croplands. A closer look into the weekly time series reveals the C fluctuation through time and space for each land cover type.

  11. TargetNet: a web service for predicting potential drug-target interaction profiling via multi-target SAR models.

    Science.gov (United States)

    Yao, Zhi-Jiang; Dong, Jie; Che, Yu-Jing; Zhu, Min-Feng; Wen, Ming; Wang, Ning-Ning; Wang, Shan; Lu, Ai-Ping; Cao, Dong-Sheng

    2016-05-01

    Drug-target interactions (DTIs) are central to current drug discovery processes and public health fields. Analyzing the DTI profiling of the drugs helps to infer drug indications, adverse drug reactions, drug-drug interactions, and drug mode of actions. Therefore, it is of high importance to reliably and fast predict DTI profiling of the drugs on a genome-scale level. Here, we develop the TargetNet server, which can make real-time DTI predictions based only on molecular structures, following the spirit of multi-target SAR methodology. Naïve Bayes models together with various molecular fingerprints were employed to construct prediction models. Ensemble learning from these fingerprints was also provided to improve the prediction ability. When the user submits a molecule, the server will predict the activity of the user's molecule across 623 human proteins by the established high quality SAR model, thus generating a DTI profiling that can be used as a feature vector of chemicals for wide applications. The 623 SAR models related to 623 human proteins were strictly evaluated and validated by several model validation strategies, resulting in the AUC scores of 75-100 %. We applied the generated DTI profiling to successfully predict potential targets, toxicity classification, drug-drug interactions, and drug mode of action, which sufficiently demonstrated the wide application value of the potential DTI profiling. The TargetNet webserver is designed based on the Django framework in Python, and is freely accessible at http://targetnet.scbdd.com .

  12. TargetNet: a web service for predicting potential drug-target interaction profiling via multi-target SAR models

    Science.gov (United States)

    Yao, Zhi-Jiang; Dong, Jie; Che, Yu-Jing; Zhu, Min-Feng; Wen, Ming; Wang, Ning-Ning; Wang, Shan; Lu, Ai-Ping; Cao, Dong-Sheng

    2016-05-01

    Drug-target interactions (DTIs) are central to current drug discovery processes and public health fields. Analyzing the DTI profiling of the drugs helps to infer drug indications, adverse drug reactions, drug-drug interactions, and drug mode of actions. Therefore, it is of high importance to reliably and fast predict DTI profiling of the drugs on a genome-scale level. Here, we develop the TargetNet server, which can make real-time DTI predictions based only on molecular structures, following the spirit of multi-target SAR methodology. Naïve Bayes models together with various molecular fingerprints were employed to construct prediction models. Ensemble learning from these fingerprints was also provided to improve the prediction ability. When the user submits a molecule, the server will predict the activity of the user's molecule across 623 human proteins by the established high quality SAR model, thus generating a DTI profiling that can be used as a feature vector of chemicals for wide applications. The 623 SAR models related to 623 human proteins were strictly evaluated and validated by several model validation strategies, resulting in the AUC scores of 75-100 %. We applied the generated DTI profiling to successfully predict potential targets, toxicity classification, drug-drug interactions, and drug mode of action, which sufficiently demonstrated the wide application value of the potential DTI profiling. The TargetNet webserver is designed based on the Django framework in Python, and is freely accessible at http://targetnet.scbdd.com.

  13. Grassland and Cropland Net Ecosystem Production of the U.S. Great Plains: Regression Tree Model Development and Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Bruce Wylie

    2016-11-01

    Full Text Available This paper presents the methodology and results of two ecological-based net ecosystem production (NEP regression tree models capable of up scaling measurements made at various flux tower sites throughout the U.S. Great Plains. Separate grassland and cropland NEP regression tree models were trained using various remote sensing data and other biogeophysical data, along with 15 flux towers contributing to the grassland model and 15 flux towers for the cropland model. The models yielded weekly mean daily grassland and cropland NEP maps of the U.S. Great Plains at 250 m resolution for 2000–2008. The grassland and cropland NEP maps were spatially summarized and statistically compared. The results of this study indicate that grassland and cropland ecosystems generally performed as weak net carbon (C sinks, absorbing more C from the atmosphere than they released from 2000 to 2008. Grasslands demonstrated higher carbon sink potential (139 g C·m−2·year−1 than non-irrigated croplands. A closer look into the weekly time series reveals the C fluctuation through time and space for each land cover type.

  14. Modelling M/G/1 queueing systems with server vacations using stochastic Petri nets

    Directory of Open Access Journals (Sweden)

    K Ramanath

    2006-12-01

    Full Text Available The theory of non-Markovian stochastic Petri nets is employed in this paper to derive an alternative method for studying the steady state behaviour of the M/G/1 vacation queueing system with a limited service discipline. Three types of vacation schemes are considered, and sytems with both a finite population and those with an infinite population (but finite capacity are considered. Simple numerical examples are also provided to illustrate the functionality of the methods and some useful performance measures for the system are obtained.

  15. Modeling the Scheduling Problem of Identical Parallel Machines with Load Balancing by Time Petri Nets

    Directory of Open Access Journals (Sweden)

    Sekhri Larbi

    2014-12-01

    Full Text Available The optimal resources allocation to tasks was the primary objective of the research dealing with scheduling problems. These problems are characterized by their complexity, known as NP-hard in most cases. Currently with the evolution of technology, classical methods are inadequate because they degrade system performance (inflexibility, inefficient resources using policy, etc.. In the context of parallel and distributed systems, several computing units process multitasking applications in concurrent way. Main goal of such process is to schedule tasks and map them on the appropriate machines to achieve the optimal overall system performance (Minimize the Make-span and balance the load among the machines. In this paper we present a Time Petri Net (TPN based approach to solve the scheduling problem by mapping each entity (tasks, resources and constraints to correspondent one in the TPN. In this case, the scheduling problem can be reduced to finding an optimal sequence of transitions leading from an initial marking to a final one. Our approach improves the classical mapping algorithms by introducing a control over resources allocation and by taking into consideration the resource balancing aspect leading to an acceptable state of the system. The approach is applied to a specific class of problems where the machines are parallel and identical. This class is analyzed by using the TiNA (Time Net Analyzer tool software developed in the LAAS laboratory (Toulouse, France.

  16. Discrepant estimates of primary and export production from satellite algorithms, a biogeochemical model, and geochemical tracer measurements in the North Pacific Ocean

    Science.gov (United States)

    Palevsky, Hilary I.; Quay, Paul D.; Nicholson, David P.

    2016-08-01

    Estimates of primary and export production (PP and EP) based on satellite remote sensing algorithms and global biogeochemical models are widely used to provide year-round global coverage not available from direct observations. However, observational data to validate these approaches are limited. We find that no single satellite algorithm or model can reproduce seasonal and annual geochemically determined PP, export efficiency (EP/PP), and EP rates throughout the North Pacific basin, based on comparisons throughout the full annual cycle at time series stations in the subarctic and subtropical gyres and basin-wide regions sampled by container ship transects. The high-latitude regions show large PP discrepancies in winter and spring and strong effects of deep winter mixed layers on annual EP that cannot be accounted for in current satellite-based approaches. These results underscore the need to evaluate satellite- and model-based estimates using multiple productivity parameters measured over broad ocean regions throughout the annual cycle.

  17. National Geochemical Database: Concentrate

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemistry of concentrates from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US and...

  18. XAr/T-net: an Artifact-centered business process modeling method%XAr/T-net:一种用于以业务单据为中心的业务流程建模方法

    Institute of Scientific and Technical Information of China (English)

    王颖; 刘国华; 黄震

    2013-01-01

    To analyze the characteristics of key data in business process and the interaction between them,a variant of high-level Petri net-XAr/T-net was proposed by describing the structure and operation of Artifact with eXtensible Markup Language (XML),and the Artifact-centered business process was also modeled.The research result showed that XAr/T-net model not only could analyze the uniqueness,accessibility and persistence of Artifact in each independent business process,but also express the interaction between different types Artifact was expressed in business process.%为分析业务流程中关键数据的特性及数据之间的交互关系,用可扩展标记语言形式描述业务流程中的数据实体Artifact的结构及其操作,提出一种高级Petri网的变体XAr/T-net,对以Artifact为中心的业务流程进行建模.研究结果表明,XAr/T-net模型既可以分析各个独立的业务子流程中Artifact的唯一性、可达性和持久性,又可以表达业务流程中各类型Artifact之间的交互.

  19. Is different better? Models of teaching and their influence on the net financial outcome for general practice teaching posts

    Science.gov (United States)

    2011-01-01

    Background In Australia, training for general practice (GP) occurs within private practices and their involvement in teaching can have significant financial costs. At the same time there are growing demands for clinical places for all disciplines and for GP there is concern that there are insufficient teaching practices to meet the demand at the medical student, prevocational and vocational training levels. One option to address this may be to change how teaching occurs in the practice. A question that arises in posing such an option is whether different models of teaching change the costs for a teaching practice. The aim of this study is to determine the net financial outcome of teaching models in private GP. Methods Modelling the financial implications for a range of teaching options using a costing framework developed from a survey of teaching practices in South Australia. Each option was compared with the traditional model of teaching where one GP supervisor is singularly responsible for one learner. The main outcome measure was net financial outcome per week. Decisions on the model cost parameters were made by the study's Steering Group which comprised of experienced GP supervisors. Four teaching models are presented. Model 1 investigates the gains from teaching multiple same level learners, Models 2 and 3, the benefits of vertically integrated teaching using different permutations, and Model 4 the concept of a GP teacher who undertakes all the teaching. Results There was a significant increase in net benefits of Aus$547 per week (95% confidence intervals $459, $668) to the practice when a GP taught two same level learners (Model 1) and when a senior registrar participated in teaching a prevocational doctor (Model 3, Aus$263, 95% confidence intervals $80, $570). For Model 2, a practice could significantly reduce the loss if a registrar was involved in vertically integrated teaching which included the training of a medical student (Aus$551, 95% confidence

  20. Is different better? Models of teaching and their influence on the net financial outcome for general practice teaching posts

    Directory of Open Access Journals (Sweden)

    Cheah Carolyn

    2011-07-01

    Full Text Available Abstract Background In Australia, training for general practice (GP occurs within private practices and their involvement in teaching can have significant financial costs. At the same time there are growing demands for clinical places for all disciplines and for GP there is concern that there are insufficient teaching practices to meet the demand at the medical student, prevocational and vocational training levels. One option to address this may be to change how teaching occurs in the practice. A question that arises in posing such an option is whether different models of teaching change the costs for a teaching practice. The aim of this study is to determine the net financial outcome of teaching models in private GP. Methods Modelling the financial implications for a range of teaching options using a costing framework developed from a survey of teaching practices in South Australia. Each option was compared with the traditional model of teaching where one GP supervisor is singularly responsible for one learner. The main outcome measure was net financial outcome per week. Decisions on the model cost parameters were made by the study's Steering Group which comprised of experienced GP supervisors. Four teaching models are presented. Model 1 investigates the gains from teaching multiple same level learners, Models 2 and 3, the benefits of vertically integrated teaching using different permutations, and Model 4 the concept of a GP teacher who undertakes all the teaching. Results There was a significant increase in net benefits of Aus$547 per week (95% confidence intervals $459, $668 to the practice when a GP taught two same level learners (Model 1 and when a senior registrar participated in teaching a prevocational doctor (Model 3, Aus$263, 95% confidence intervals $80, $570. For Model 2, a practice could significantly reduce the loss if a registrar was involved in vertically integrated teaching which included the training of a medical student (Aus

  1. Numerical simulation of in-situ chemical oxidation (ISCO) and biodegradation of petroleum hydrocarbons using a coupled model for bio-geochemical reactive transport

    Science.gov (United States)

    Marin, I. S.; Molson, J. W.

    2013-05-01

    Petroleum hydrocarbons (PHCs) are a major source of groundwater contamination, being a worldwide and well-known problem. Formed by a complex mixture of hundreds of organic compounds (including BTEX - benzene, toluene, ethylbenzene and xylenes), many of which are toxic and persistent in the subsurface and are capable of creating a serious risk to human health. Several remediation technologies can be used to clean-up PHC contamination. In-situ chemical oxidation (ISCO) and intrinsic bioremediation (IBR) are two promising techniques that can be applied in this case. However, the interaction of these processes with the background aquifer geochemistry and the design of an efficient treatment presents a challenge. Here we show the development and application of BIONAPL/Phreeqc, a modeling tool capable of simulating groundwater flow, contaminant transport with coupled biological and geochemical processes in porous or fractured porous media. BIONAPL/Phreeqc is based on the well-tested BIONAPL/3D model, using a powerful finite element simulation engine, capable of simulating non-aqueous phase liquid (NAPL) dissolution, density-dependent advective-dispersive transport, and solving the geochemical and kinetic processes with the library Phreeqc. To validate the model, we compared BIONAPL/Phreeqc with results from the literature for different biodegradation processes and different geometries, with good agreement. We then used the model to simulate the behavior of sodium persulfate (NaS2O8) as an oxidant for BTEX degradation, coupled with sequential biodegradation in a 2D case and to evaluate the effect of inorganic geochemistry reactions. The results show the advantages of a treatment train remediation scheme based on ISCO and IBR. The numerical performance and stability of the integrated BIONAPL/Phreeqc model was also verified.

  2. Bio-inspired Artificial Intelligence: А Generalized Net Model of the Regularization Process in MLP

    Directory of Open Access Journals (Sweden)

    Stanimir Surchev

    2013-10-01

    Full Text Available Many objects and processes inspired by the nature have been recreated by the scientists. The inspiration to create a Multilayer Neural Network came from human brain as member of the group. It possesses complicated structure and it is difficult to recreate, because of the existence of too many processes that require different solving methods. The aim of the following paper is to describe one of the methods that improve learning process of Artificial Neural Network. The proposed generalized net method presents Regularization process in Multilayer Neural Network. The purpose of verification is to protect the neural network from overfitting. The regularization is commonly used in neural network training process. Many methods of verification are present, the subject of interest is the one known as Regularization. It contains function in order to set weights and biases with smaller values to protect from overfitting.

  3. Analysis of Petri net model and task planning heuristic algorithms for product reconfiguration

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Reconfiguration planning is recognized as an important factor for reducing the cost of manufacturing reconfigurable products, and the associated main task is to generate a set of optimal or near-optimal reconfiguration sequences using some effect algorithms. A method is developed to generate a Petri net as the reconfiguration tree to represent two-state-transit of product, which solved the representation problem of reconfiguring interfaces replacement. Relating with this method, two heuristic algorithms are proposed to generate task sequences which considering economics to search reconfiguration paths effectively. At last,an objective evaluation is applied to compare these two heuristic algorithms to other ones. The developed reconfiguration task planning heuristic algorithms can generate better strategies and plans for reconfiguration. The research finds are exemplified with struts reconfiguration of reconfigurable parallel kinematics machine (RPKM).

  4. Ar/T-Net:一种面向Artifact的业务过程概念模型%Ar/T-Net: An Artifact-Oriented Business Process Conceptual Model

    Institute of Scientific and Technical Information of China (English)

    王颖; 赵威; 赵丹枫; 刘国华

    2010-01-01

    以数据为中心是业务过程管理发展的新趋势,面向Artifact的业务过程管理是一种具有代表性的以数据为中心的业务过程管理技术.概念模型设计是面向Artifact的业务过程设计的关键步骤,但目前还没有成型的建模和分析工具.利用谓词/变迁Petri-Net建模的优势,根据Artifact的特点,用嵌套关系模式定义Artifact的结构;以描述Artifact的嵌套关系模式作为谓词,提出了一种适合于概念模型设计的谓词/变迁Petri-Net,即Ar/T-Net.以可达性分析为例,讨论了Ar/T-Net的功能.

  5. The Impact of Outliers on Net-Benefit Regression Model in Cost-Effectiveness Analysis.

    Science.gov (United States)

    Wen, Yu-Wen; Tsai, Yi-Wen; Wu, David Bin-Chia; Chen, Pei-Fen

    2013-01-01

    Ordinary least square (OLS) in regression has been widely used to analyze patient-level data in cost-effectiveness analysis (CEA). However, the estimates, inference and decision making in the economic evaluation based on OLS estimation may be biased by the presence of outliers. Instead, robust estimation can remain unaffected and provide result which is resistant to outliers. The objective of this study is to explore the impact of outliers on net-benefit regression (NBR) in CEA using OLS and to propose a potential solution by using robust estimations, i.e. Huber M-estimation, Hampel M-estimation, Tukey's bisquare M-estimation, MM-estimation and least trimming square estimation. Simulations under different outlier-generating scenarios and an empirical example were used to obtain the regression estimates of NBR by OLS and five robust estimations. Empirical size and empirical power of both OLS and robust estimations were then compared in the context of hypothesis testing. Simulations showed that the five robust approaches compared with OLS estimation led to lower empirical sizes and achieved higher empirical powers in testing cost-effectiveness. Using real example of antiplatelet therapy, the estimated incremental net-benefit by OLS estimation was lower than those by robust approaches because of outliers in cost data. Robust estimations demonstrated higher probability of cost-effectiveness compared to OLS estimation. The presence of outliers can bias the results of NBR and its interpretations. It is recommended that the use of robust estimation in NBR can be an appropriate method to avoid such biased decision making.

  6. A geochemical transport model for redox-controlled movement of mineral fronts in groundwater flow systems: A case of nitrate removal by oxidation of pyrite

    Science.gov (United States)

    Engesgaard, Peter; Kipp, Kenneth L.

    1992-01-01

    A one-dimensional prototype geochemical transport model was developed in order to handle simultaneous precipitation-dissolution and oxidation-reduction reactions governed by chemical equilibria. Total aqueous component concentrations are the primary dependent variables, and a sequential iterative approach is used for the calculation. The model was verified by analytical and numerical comparisons and is able to simulate sharp mineral fronts. At a site in Denmark, denitrification has been observed by oxidation of pyrite. Simulation of nitrate movement at this site showed a redox front movement rate of 0.58 m yr−1, which agreed with calculations of others. It appears that the sequential iterative approach is the most practical for extension to multidimensional simulation and for handling large numbers of components and reactions. However, slow convergence may limit the size of redox systems that can be handled.

  7. The effects of physical and geochemical heterogeneities on hydro-geochemical transport and effective reaction rates.

    Science.gov (United States)

    Atchley, Adam L; Navarre-Sitchler, Alexis K; Maxwell, Reed M

    2014-09-01

    The role of coupled physical and geochemical heterogeneities in hydro-geochemical transport is investigated by simulating three-dimensional transport in a heterogeneous system with kinetic mineral reactions. Ensembles of 100 physically heterogeneous realizations were simulated for three geochemical conditions: 1) spatially homogeneous reactive mineral surface area, 2) reactive surface area positively correlated to hydraulic heterogeneity, and 3) reactive surface area negatively correlated to hydraulic heterogeneity. Groundwater chemistry and the corresponding effective reaction rates were calculated at three transverse planes to quantify differences in plume evolution due to heterogeneity in mineral reaction rates and solute residence time (τ). The model is based on a hypothetical CO2 intrusion into groundwater from a carbon capture utilization and storage (CCUS) operation where CO2 dissolution and formation of carbonic acid created geochemical dis-equilibrium between fluids and the mineral galena that resulted in increased aqueous lead (Pb(2+)) concentrations. Calcite dissolution buffered the pH change and created conditions of galena oversaturation, which then reduced lead concentrations along the flow path. Near the leak kinetic geochemical reactions control the release of solutes into the fluid, but further along the flow path mineral solubility controls solute concentrations. Simulation results demonstrate the impact of heterogeneous distribution of geochemical reactive surface area in coordination with physical heterogeneity on the effective reaction rate (Krxn,eff) and Pb(2+) concentrations within the plume. Dissimilarities between ensemble Pb(2+) concentration and Krxn,eff are attributed to how geochemical heterogeneity affects the time (τeq) and therefore advection distance (Leq) required for the system to re-establish geochemical equilibrium. Only after geochemical equilibrium is re-established, Krxn,eff and Pb(2+) concentrations are the same for all

  8. A unified and efficient framework for court-net sports video analysis using 3D camera modeling

    Science.gov (United States)

    Han, Jungong; de With, Peter H. N.

    2007-01-01

    The extensive amount of video data stored on available media (hard and optical disks) necessitates video content analysis, which is a cornerstone for different user-friendly applications, such as, smart video retrieval and intelligent video summarization. This paper aims at finding a unified and efficient framework for court-net sports video analysis. We concentrate on techniques that are generally applicable for more than one sports type to come to a unified approach. To this end, our framework employs the concept of multi-level analysis, where a novel 3-D camera modeling is utilized to bridge the gap between the object-level and the scene-level analysis. The new 3-D camera modeling is based on collecting features points from two planes, which are perpendicular to each other, so that a true 3-D reference is obtained. Another important contribution is a new tracking algorithm for the objects (i.e. players). The algorithm can track up to four players simultaneously. The complete system contributes to summarization by various forms of information, of which the most important are the moving trajectory and real-speed of each player, as well as 3-D height information of objects and the semantic event segments in a game. We illustrate the performance of the proposed system by evaluating it for a variety of court-net sports videos containing badminton, tennis and volleyball, and we show that the feature detection performance is above 92% and events detection about 90%.

  9. Coloured Petri Nets

    CERN Document Server

    Jensen, Kurt

    2009-01-01

    Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. This book introduces the constructs of the CPN modelling language and presents the related analysis methods. It provides a comprehensive road map for the practical use of CPN.

  10. Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.

    Directory of Open Access Journals (Sweden)

    Laith Yakob

    Full Text Available Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs. In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.

  11. Nearly Net-Zero Exergy Districts as Models for Smart Energy Systems

    Directory of Open Access Journals (Sweden)

    Şiir Kilkiş

    2017-03-01

    Full Text Available The planning of urban settlements requires a targeted approach towards more sustainable energy, water, and environment systems. This research work analyses the city of Uppsala and a district that is an urban renewal project at the site of former high voltage power lines, namely Östra Sala backe, which will have a new energy concept. The latter is analysed based on proposals for two phases that aim to reach a net-zero district target based on the quality of energy (exergy. An indicator set with five main categories is introduced based on per capita values to enable a comparable basis between the scales of the city and the district, including exergy per capita as a new indicator. The present status of Uppsala is further analysed based on Sankey diagrams to provide insight into the present urban metabolism of the city. The results indicate that the best practice values of Östra Sala backe based on phase two can achieve significant savings in per capita values, which include 5.5 MWh of energy usage, 6.1 MWh of exergy consumption, 33 m3 of water consumption, 22 kg of waste generation, and 4.2 tonnes of carbon dioxide (CO2 emissions. Additional scenarios for Uppsala indicate that the district can be about 10 years ahead of the city’s existing performance.

  12. USING OF NET PRESENT VALUE (NPV) TO TEST THE INTEGRATED MODEL IN BUILDING MANAGEMENT INFORMATION SYSTEMS

    OpenAIRE

    Omar, Mohammad; Abdullah, Khairul

    2017-01-01

    The integrated model is a new model that is recently developed in order to build the management information systems (MIS's) by using the classical approach system development methodology. The integrated model aims to address the drawbacks of the classical approach in consumption additional time and cost while building the MIS's. The integrated model was subjected to two tests by using the mathematical probability theories in order to ensure the validity of the integrated model in it...

  13. Modelling effects of seasonal variation in water table depth on net ecosystem CO2 exchange of a tropical peatland

    Directory of Open Access Journals (Sweden)

    M. Mezbahuddin

    2013-08-01

    Full Text Available Seasonal variation in water table depth (WTD determines the balance between aggradation and degradation of tropical peatlands. Longer dry seasons together with human interventions (e.g. drainage can cause WTD drawdowns making tropical peatland C storage highly vulnerable. Better predictive capacity for effects of WTD on net CO2 exchange is thus essential to guide conservation of tropical peat deposits. Mathematical modelling of basic eco-hydrological processes under site-specific conditions can provide such predictive capacity. We hereby deploy a mathematical model ecosys to study effects of seasonal variation in WTD on net ecosystem productivity (NEP of an Indonesian peatland. We simulated lower NEPs (~ –2 g C m–2 d–1 during rainy seasons with shallow WTD, higher NEPs (~ +1 g C m–2 d–1 during early dry seasons with intermediate WTD and again lower NEPs (~ –4 g C mm–2 d–1 during late dry seasons with deep WTD during 2002–2005. These values were corroborated by regressions (P 2 fluxes which yielded R2 > 0.8, intercepts approaching 0 and slopes approaching 1. We also simulated a gradual increase in annual NEPs from 2002 (−609 g C m–2 to 2005 (−373 g C m–2 with decreasing WTD which was corroborated by EC-gap filled annual NEP estimates. These WTD effects on NEP were modelled from basic eco-hydrological processes including microbial and root oxidation-reduction reactions driven by soil and root O2 transport and uptake which in turn drove soil and plant C, N and P transformations within a soil-plant-atmosphere water transfer scheme driven by water potential gradients. This modelling should therefore provide a predictive capacity for WTD management programs to reduce tropical peat degradation.

  14. Geochemical Investigations of Groundwater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)

    2006-05-15

    The report describes geochemical parameters and methods that provide information about the hydrodynamic stability of groundwaters in low permeability fractured rocks that are potential hosts for radioactive waste repositories. Hydrodynamic stability describes the propensity for changes in groundwater flows over long timescales, in terms of flow rates and flow directions. Hydrodynamic changes may also cause changes in water compositions, but the related issue of geochemical stability of a potential repository host rock system is outside the scope of this report. The main approaches to assessing groundwater stability are numerical modelling, measurement and interpretation of geochemical indicators in groundwater compositions, and analyses and interpretations of secondary minerals and fluid inclusions in these minerals. This report covers the latter two topics, with emphasis on geochemical indicators. The extent to which palaeohydrogeology and geochemical stability indicators have been used in past safety cases is reviewed. It has been very variable, both in terms of the scenarios considered, the stability indicators considered and the extent to which the information was explicitly or implicitly used in assessing FEPs and scenarios in the safety cases. Geochemical indicators of hydrodynamic stability provide various categories of information that are of hydrogeological relevance. Information about groundwater mixing, flows and water sources is potentially provided by the total salinity of groundwaters, their contents of specific non-reactive solutes (principally chloride) and possibly of other solutes, the stable isotopic ratio of water, and certain characteristics of secondary minerals and fluid inclusions. Information pertaining directly to groundwater ages and the timing of water and solute movements is provided by isotopic systems including tritium, carbon-14, chlorine-36, stable oxygen and hydrogen isotopes, uranium isotopes and dissolved mobile gases in

  15. Evaluation of Geochemical Fracture Conductivity Alterations in Shale under Laboratory Conditions

    Science.gov (United States)

    Radonjic, M.; Olabode, A.

    2015-12-01

    In large scale subsurface injection of carbondioxide as obtainable in carbon sequestration programs and in environmentally friendly hydraulic fracturing processes (using supercritical CO2), rock-fluid interaction can affect reservoir and seal rocks properties which are essential in monitoring the progress of these operations. The mineralogical components of sedimentary rocks are geochemically active particularly under enormous earth stresses. While geomechanical properties such as rock stiffness, Poisson's ratio and fracture geometry largely govern fluid flow characteristics in deep fractured formations, the effect of mineralization can lead to flow impedance in the presence of favorable geochemical and thermodynamic conditions. Experimental works which employed the use of analytical tools such as ICP-OES, XRD, SEM/EDS, TOC and BET techniques in investigating diagenetic and micro-structural properties of crushed shale caprock/CO2-brine system concluded that net precipitation reaction processes can affect the distribution of petrophysical nanopores in the shale as a result of rock-fluid interactions. Simulation results previously reported, suggest that influx-induced mineral dissolution/precipitation reactions within clay-based sedimentary rocks can continuously close micro-fracture networks, though injection pressure and effective-stress transformation first rapidly expand these fractures. This experimental modelling research investigated the impact of in-situ geochemical precipitation on conductivity of fractures under geomechanical stress conditions. Conductivity is measured as differential-pressure drop equivalence, using a pressure pulse-decay liquid permeametry/core flooding system, as geochemically saturated-fluid is transported through composite cores with embedded micro-tubings that mimic fractures. The reactive fluid is generated from crushed shale rocks of known mineralogical composition when flooded with aqueous CO2 at elevated temperature and pressure

  16. Distribution, Microfabric, and Geochemical Characteristics of Siliceous Rocks in Central Orogenic Belt, China: Implications for a Hydrothermal Sedimentation Model

    Directory of Open Access Journals (Sweden)

    Hongzhong Li

    2014-01-01

    Full Text Available Marine siliceous rocks are widely distributed in the central orogenic belt (COB of China and have a close connection to the geological evolution and metallogenesis. They display periodic distributions from Mesoproterozoic to Jurassic with positive peaks in the Mesoproterozoic, Cambrian—Ordovician, and Carboniferous—Permian and their deposition is enhanced by the tensional geological settings. The compressional regimes during the Jinning, Caledonian, Hercynian, Indosinian, and Yanshanian orogenies resulted in sudden descent in their distribution. The siliceous rocks of the Bafangshan-Erlihe ore deposit include authigenic quartz, syn-depositional metal sulphides, and scattered carbonate minerals. Their SiO2 content (71.08–95.30%, Ba (42.45–503.0 ppm, and ΣREE (3.28–19.75 ppm suggest a hydrothermal sedimentation origin. As evidenced by the Al/(Al + Fe + Mn, Sc/Th, (La/YbN, and (La/CeN ratios and δCe values, the studied siliceous rocks were deposited in a marginal sea basin of a limited ocean. We suggest that the Bafangshan-Erlihe area experienced high- and low-temperature stages of hydrothermal activities. The hydrothermal sediments of the former stage include metal sulphides and silica, while the latter was mainly composed of silica. Despite the hydrothermal sedimentation of the siliceous rocks, minor terrigenous input, magmatism, and biological activity partly contributed to geochemical features deviating from the typical hydrothermal characteristics.

  17. Formal verification of business process models using Petri nets%业务过程模型的Petri网形式化检查方法

    Institute of Scientific and Technical Information of China (English)

    邓建; 陈智; 曾家智

    2011-01-01

    为解决企业间业务协同模型形式化检查的问题,将采用标准业务过程建模符号的业务模型转换为Petri网,构造出一种可建模企业问复杂业务协同的业务过程流网.采用过程定义可扩展标记语言2.1版本,开发了一种具有通用性的业务过程模型转换和检查工具.采用业务过程流网对供应链中企业间采购订单过程进行了建模.实验结果表明,业务过程流网能将符合过程定义町扩展标记语占规范的业务模型完整地转换为Petri网,得到的Petri网易于化简和分析.%To resolve the formal checking of business collaboration model cross enterprises, a special Petri net named Business Process Flow net (BPF-net) was constructed to transform business process modeled by Business Process Modeling Notation (BPMN) into Petri nets.With the use of eXtensible Markup Language (XML) Process Definition Language (XPDL) 2.1 version, a universal tool was also developed to convert and check business process model.An inter-organizational order process in supply chain was modeled by using of BPF-net.Experimental results showed that BPF-net could transform the bueiness model which met the XPDL specifications into Petri net, and easy to be simplified and analyzed.

  18. Modeling and Analysis of Hybrid Dynamic Systems Using Hybrid Petri Nets

    OpenAIRE

    GHOMRI Latefa; Alla, Hassane

    2008-01-01

    Some extensions of PNs permitting HDS modeling were presented here. The first models to be presented are continuous PNs. This model may be used for modeling either a continuous system or a discrete system. In this case, it is an approximation that is often satisfactory. Hybrid PNs combine in the same formalism a discrete PN and a continuous PN. Two hybrid PN models were considered in this chapter. The first, called the hybrid PN, has a deterministic behavior; this means that we can predict th...

  19. Changes in net ecosystem productivity and greenhouse gas exchange with fertilization of Douglas fir: Mathematical modeling in ecosys

    Science.gov (United States)

    Grant, R. F.; Black, T. A.; Jassal, R. S.; Bruemmer, C.

    2010-12-01

    The application of nitrogen fertilizers to Douglas fir forests is known to raise net ecosystem productivity (NEP), but also N2O emissions, the CO2 equivalent of which may offset gains in NEP when accounting for net greenhouse gas (GHG) exchange. However, total changes in NEP and N2O emissions caused by fertilizer between times of application and harvest, while needed for national GHG inventories, are difficult to quantify except through modeling. In this study, integrated hypotheses for soil and plant N processes within the ecosystem model ecosys were tested against changes in CO2 and N2O fluxes recorded with eddy covariance (EC) and surface flux chambers for 1 year after applying 20 g N m-2 of urea to a mature Douglas fir stand in British Columbia. Parameters from annual regressions of hourly modeled versus measured CO2 fluxes conducted before and after fertilization were unchanged (b = 1.0, R2 = 0.8, RMSD = 3.4 μmol m-2 s-1), indicating that model hypotheses for soil and plant N processes did not introduce bias into CO2 fluxes modeled after fertilization. These model hypotheses were then used to project changes in NEP and GHG exchange attributed to the fertilizer during the following 10 years until likely harvest of the Douglas fir stand. Increased CO2 uptake caused modeled and EC-derived annual NEP to rise from 443 and 386 g C m-2 in the year before fertilization to 591 and 547 g C m-2 in the year after. These gains contributed to a sustained rise in modeled wood C production with fertilization, which was partly offset by a decline in soil C attributed in the model to reduced root C productivity and litterfall. Gains in net CO2 uptake were further offset in the model by a rise of 0.74 g N m-2 yr-1 in N2O emissions during the first year after fertilization, which was consistent with one of 1.05 g N m-2 yr-1 estimated from surface flux chamber measurements. Further N2O emissions were neither modeled nor measured after the first year. At the end of the 11 year

  20. Fluid Source-based Modeling of Melt Initiation within the Subduction Zone Mantle Wedge: Implications for Geochemical Trends in Arc Lavas

    Science.gov (United States)

    Hebert, L. B.; Asimow, P. D.; Antoshechkina, P. M.

    2008-12-01

    The GyPSM-S (Geodynamic and Petrological Synthesis Model for Subduction) scheme couples a petrological model (pHMELTS) with a 2D thermal and variable viscosity flow model (ConMan), to describe and compare fundamental processes occurring within subduction zones. Here we supplement basic GyPSM-S models with a more sophisticated treatment of trace element partitioning in the fluid phase and of melt transport regimes to investigate the influences of slab fluid source lithology and fluid transport mechanisms on melt geochemistry, the implications of mantle source depletion related to fluid fluxing, and potential melt migration processes. Changing model parameters indicate that slab age and slab dip are the primary controls on slab-adjacent low-viscosity channel (LVC) shape and thickness, due to changes in the fluid release patterns. Slab age and convergence velocity, which contribute to the slab thermal structure, are significant for the locations of dehydration reactions within the different lithological layers of the slab. The fluid source lithology determines the fluid flux and the fluid-mobile trace element input to the wedge. This study focuses on two cases that represent extremes within our model set, an old slab with a low rate of convergence and and a relatively young slab with a higher rate of convergence. Results are compared to actual geochemical datasets for the Izu-Bonin intra-oceanic subduction system and the Central Costa Rican part of the Central American arc. We find that there is a progression of geochemical characteristics described in studies of cross-arc and along-arc lavas that can be duplicated assuming (i) limited fluid-rock interaction within the mantle wedge and (ii) that melt migration preserves the spatial distinction among melts initiated in different areas of the wedge. Specifically, volcanic front lavas have significant contributions from shallower slab fluid sources, and rear-arc lavas have significant contributions from deeper slab fluid

  1. Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

    Science.gov (United States)

    Lee, Younjoo J.; Matrai, Patricia A.; Friedrichs, Marjorie A. M.; Saba, Vincent S.; Aumont, Olivier; Babin, Marcel; Buitenhuis, Erik T.; Chevallier, Matthieu; de Mora, Lee; Dessert, Morgane; Dunne, John P.; Ellingsen, Ingrid H.; Feldman, Doron; Frouin, Robert; Gehlen, Marion; Gorgues, Thomas; Ilyina, Tatiana; Jin, Meibing; John, Jasmin G.; Lawrence, Jon; Manizza, Manfredi; Menkes, Christophe E.; Perruche, Coralie; Le Fouest, Vincent; Popova, Ekaterina E.; Romanou, Anastasia; Samuelsen, Annette; Schwinger, Jörg; Séférian, Roland; Stock, Charles A.; Tjiputra, Jerry; Tremblay, L. Bruno; Ueyoshi, Kyozo; Vichi, Marcello; Yool, Andrew; Zhang, Jinlun

    2016-12-01

    The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO3), mixed layer depth (MLD), euphotic layer depth (Zeu), and sea ice concentration, by comparing results against a newly updated, quality-controlled in situ NPP database for the Arctic Ocean (1959-2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan-Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO3, MLD, and Zeu throughout the regions. Among the models, iNPP exhibited little difference over sea ice condition (ice-free versus ice-influenced) and bottom depth (shelf versus deep ocean). The models performed relatively well for the most recent decade and toward the end of Arctic summer. In the Barents and Greenland Seas, regional model skill of surface NO3 was best associated with how well MLD was reproduced. Regionally, iNPP was relatively well simulated in the Beaufort Sea and the central Arctic Basin, where in situ NPP is low and nutrients are mostly depleted. Models performed less well at simulating iNPP in the Greenland and Chukchi Seas, despite the higher model skill in MLD and sea ice concentration, respectively. iNPP model skill was constrained by different factors in different Arctic Ocean regions. Our study suggests that better parameterization of biological and ecological microbial rates (phytoplankton growth and zooplankton grazing) are needed for improved Arctic Ocean biogeochemical modeling.

  2. An empirical model of net photosynthesis for the desert plant Hammada scoparia (Pomel) Iljin : I. Description and test of the model.

    Science.gov (United States)

    Schulze, E -D; Lange, O L; Evenari, M; Kappen, L; Buschbom, U

    1976-12-01

    An empirical model for describing daily courses of net photosynthesis in Hammada scoparia is being developed. The model is based on the functional relationships, by which various environmental factors affect the photosynthetic activity and which can be measured by experiment in the field. In a sequence of steady-states daily courses of net photosynthesis are predicted during a growing season considering the variability of the physiological states and the capacity for regulative adaptations. The rate of net photosynthesis at a certain date is calculated from the maximal rate of CO2 uptake being expected at that season and from the effects of light, temperature, and air humidity which are scaled from 0 to 1. All factors are connected multiplicatively. The light function accounts for the seasonal changes in the light curve, the temperature function is based on the seasonal shift of the temperature optimum, and the humidity function considers the increasing sensitivity of the stomatal humidity response at increasing water stress. The model is built to be a submodel of a general ecosystem model, where various other submodels (i.e. water stress model, phenology model) are supplied. The present model is tested by predicting daily courses at extreme climatic conditions during the year and by comparing the predicted values of gas exchange with values being measured in an independent experimental procedure. The result shows that the model is able to simulate the natural behaviour of Hammada scoparia during the growing and dry season of a desert habitat. The problems of incorporating the influence of water stress, the interaction of the various factors, and the phenological aspect of the photosynthetic activity is being discussed.

  3. Introduktion til udvikling af bayesianske net

    DEFF Research Database (Denmark)

    Aagaard, Morten

    2007-01-01

    Bogen introducerer på let og uformelt de centrale grundbegreber i bayesianske net og introducerer til en udviklingsmetode for software, som inkluderer bayesianske net. Metoden kaldes BNAD og inkluderer aktiviteterne preprojekt, kvalitativ modellering, kvantitativ modellering samt...

  4. The hydrothermal system of the Domuyo volcanic complex (Argentina): A conceptual model based on new geochemical and isotopic evidences

    Science.gov (United States)

    Tassi, F.; Liccioli, C.; Agusto, M.; Chiodini, G.; Vaselli, O.; Calabrese, S.; Pecoraino, G.; Tempesti, L.; Caponi, C.; Fiebig, J.; Caliro, S.; Caselli, A.

    2016-12-01

    The Domuyo volcanic complex (Neuquén Province, Argentina) hosts one of the most promising geothermal systems of Patagonia, giving rise to thermal manifestations discharging hot and Cl--rich fluids. This study reports a complete geochemical dataset of gas and water samples collected in three years (2013, 2014 and 2015) from the main fluid discharges of this area. The chemical and isotopic composition (δD-H2O and δ18O-H2O) of waters indicates that rainwater and snow melting are the primary recharge of a hydrothermal reservoir located at relative shallow depth (400-600 m) possibly connected to a second deeper (2-3 km) reservoir. Reactive magmatic gases are completely scrubbed by the hydrothermal aquifer(s), whereas interaction of meteoric waters at the surface causes a significant air contamination and dilution of the fluid discharges located along the creeks at the foothill of the Cerro Domuyo edifice. Thermal discharges located at relatively high altitude ( 3150 m a.s.l.), namely Bramadora, are less affected by this process, as also shown by their relatively high R/Ra values (up to 6.91) pointing to the occurrence of an actively degassing magma batch located at an unknown depth. Gas and solute geothermometry suggests equilibrium temperatures up to 220-240 °C likely referred to the shallower hydrothermal reservoir. These results, confirming the promising indications of the preliminary surveys carried out in the 1980‧s, provide useful information for a reliable estimation of the geothermal potential of this extinct volcanic system, although a detailed geophysical measurements is required for the correct estimation of depth and dimensions of the fluid reservoir(s).

  5. Simulating spatiotemporal dynamics of sichuan grassland net primary productivity using the CASA model and in situ observations.

    Science.gov (United States)

    Tang, Chuanjiang; Fu, Xinyu; Jiang, Dong; Fu, Jingying; Zhang, Xinyue; Zhou, Su

    2014-01-01

    Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (ε), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε) varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000-5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

  6. Technical note: 3-hourly temporal downscaling of monthly global terrestrial biosphere model net ecosystem exchange

    Science.gov (United States)

    Fisher, Joshua B.; Sikka, Munish; Huntzinger, Deborah N.; Schwalm, Christopher; Liu, Junjie

    2016-07-01

    The land surface provides a boundary condition to atmospheric forward and flux inversion models. These models require prior estimates of CO2 fluxes at relatively high temporal resolutions (e.g., 3-hourly) because of the high frequency of atmospheric mixing and wind heterogeneity. However, land surface model CO2 fluxes are often provided at monthly time steps, typically because the land surface modeling community focuses more on time steps associated with plant phenology (e.g., seasonal) than on sub-daily phenomena. Here, we describe a new dataset created from 15 global land surface models and 4 ensemble products in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), temporally downscaled from monthly to 3-hourly output. We provide 3-hourly output for each individual model over 7 years (2004-2010), as well as an ensemble mean, a weighted ensemble mean, and the multi-model standard deviation. Output is provided in three different spatial resolutions for user preferences: 0.5° × 0.5°, 2.0° × 2.5°, and 4.0° × 5.0° (latitude × longitude). These data are publicly available from doi:10.3334/ORNLDAAC/1315.

  7. Comparing Process-Based Net Primary Productivity Models in a Mediterranean Watershed

    Science.gov (United States)

    Donmez, C.; Berberoglu, S.; Forrest, M.; Cilek, A.; Hickler, T.

    2013-10-01

    The aim of this study was to compare the estimation capability of two different process-based NPP models (CASA and LPJGUESS) in a Mediterranean watershed. Remotely sensed data and climate time series (temperature, precipitation and solar radiation) were input to these models in the example of Goksu River Basin which is located in the Eastern Mediterranean Part of Turkey. The comparison of these models was based on output variables. These variables were divided into three groups; (i) spatiallyinterpolated total NPP estimations, (ii) NPP distribution of land cover classes, (iii) annual and monthly based NPP variations. Different model approaches were evaluated within their capability to prove the relationship between annual / monthly NPP and major climatic variables. The effect of vegetation distribution on the accuracy of models was examined. The uncertainities of the CASA and LPJ-GUESS model were evaluated by incorporating remotely sensed data, percent tree cover and ground measurements. The differences between model outputs were guided to enhance modelling strategies by means of remotely sensed data and other input parameters.

  8. Geochemical Calculations Using Spreadsheets.

    Science.gov (United States)

    Dutch, Steven Ian

    1991-01-01

    Spreadsheets are well suited to many geochemical calculations, especially those that are highly repetitive. Some of the kinds of problems that can be conveniently solved with spreadsheets include elemental abundance calculations, equilibrium abundances in nuclear decay chains, and isochron calculations. (Author/PR)

  9. Biological Petri Nets

    CERN Document Server

    Wingender, E

    2011-01-01

    It was suggested some years ago that Petri nets might be well suited to modeling metabolic networks, overcoming some of the limitations encountered by the use of systems employing ODEs (ordinary differential equations). Much work has been done since then which confirms this and demonstrates the usefulness of this concept for systems biology. Petri net technology is not only intuitively understood by scientists trained in the life sciences, it also has a robust mathematical foundation and provides the required degree of flexibility. As a result it appears to be a very promising approach to mode

  10. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealized model applied to the Yangtze Estuary

    Science.gov (United States)

    Alebregtse, N. C.; de Swart, H. E.

    2016-07-01

    Tidal propagation in, and division of net water transport over different channels in an estuarine network are analyzed using a newly developed idealized model. The water motion in this model is governed by the cross-sectionally averaged shallow water equations and is forced by tides at the seaward boundaries and by river discharge. Approximate analytical solutions are constructed by means of a harmonic truncation and a perturbation expansion in a small parameter, being the ratio of tidal amplitude and depth. The net water transport results from an imposed river discharge and from residual water transport generated by nonlinear tidal rectification. Two new drivers are identified that contribute to the net water transport in tidal estuarine networks, viz. the generation of residual water transport due to gradients in dynamic pressure and due to a coupling between the tidally averaged and quarter diurnal currents through the quadratic bottom stress. The model is applied in a case study on the Yangtze Estuary, to investigate tides and division of net water transport over its multiple channels during the wet and dry season, as well as before and after the construction of the Deepwater Navigation Channel. Model results agree fairly well with observations. Process analysis reveals that the decrease in tides from dry to wet season is due to enhanced bottom stress generated by river-tide interactions. Also, the seasonal variations in net water transport are explained. It is furthermore shown and explained that due to the Deepwater Navigation Channel tidal currents have increased and net water transport has decreased in the North Passage. These changes have profound implications for net sediment transport and salinity intrusion.

  11. Regional Geochemical Division-A Tool for Delineating Geochemical Block

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2-D map. The scheme of regional geochemical division includes non-supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.

  12. The geochemical atlas of Alaska, 2016

    Science.gov (United States)

    Lee, Gregory K.; Yager, Douglas B.; Mauk, Jeffrey L.; Granitto, Matthew; Denning, Paul D.; Wang, Bronwen; Werdon, Melanie B.

    2016-06-21

    A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska; careful treatment of such data may provide significant and revealing geochemical maps that may be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas. To maximize the spatial density and extent of data coverage for statewide mapping of element distributions, we compiled and integrated analyses of more than 175,000 sediment and soil samples from three major, separate sources: the U.S. Geological Survey, the National Uranium Resource Evaluation program, and the Alaska Division of Geological & Geophysical Surveys geochemical databases. Various types of heterogeneity and deficiencies in these data presented major challenges to our development of coherently integrated datasets for modeling and mapping of element distributions. Researchers from many different organizations and disparate scientific studies collected samples that were analyzed using highly variable methods throughout a time period of more than 50 years, during which many changes in analytical techniques were developed and applied. Despite these challenges, the U.S. Geological Survey has produced a new systematically integrated compilation of sediment and soil geochemical data with an average sample site density of approximately 1 locality per 10 square kilometers (km2) for the entire State of Alaska, although density varies considerably among different areas. From that compilation, we have modeled and mapped the distributions of 68 elements, thus creating an updated geochemical atlas for the State.

  13. Dynamic modeling of thermal conditions for hot-water district-heating net- works

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shou-jun; TIAN Mao-cheng; ZHAO You-en; GUO Min

    2014-01-01

    To investigate the dynamic characteristics of the thermal conditions of hot-water district-heating networks, a dynamic modeling method is proposed with consideration of the heat dissipations in pipes and the characteristic line method is adopted to solve it. Besides, the influences of different errors, space steps and initial values on the convergence of the dynamic model results are analyzed for a model network. Finally, a part of a certain city district-heating system is simulated and the results are compared with the actual operation data in half an hour from 6 secondary heat stations. The results indicate that the relative errors for the supply pressure and temperature in 5 stations are all within 2%, except in one station, where the relative error approaches 4%. So the proposed model and algorithm are validated.

  14. Development of an RMS Model based on Colored Object-Oriented Petri Nets with Changeable Structures

    NARCIS (Netherlands)

    Zhang, Linda L.; Ittoo, Ashwin; Qi, ES; Cheng, G; Shen, JA; Dou, RL

    2009-01-01

    Current research on reconfigurable manufacturing systems (RMSs) only highlights the isolated empirical study with a limited attempt to explore the modeling and design support issues surrounding this economically important class of system development problems. This paper proposes colored

  15. net/files/pics/CEU.gif"/> A competence executive coaching model

    OpenAIRE

    Pieter Koortzen; Rudolf M. Oosthuizen

    2010-01-01

    Orientation: Psychologists in industry are increasingly required to provide executive coaching services in their organisations or as part of their consulting services. An evaluation of coaching models as well as the development needs of individuals being trained as coaches, both locally and internationally, has led the authors to believe that there is a need for a competence executive coaching model.Research purpose: The purpose of this article is to address the training and development needs...

  16. Systems Execution Modeling Technologies for Large-Scale Net-Centric Department of Defense Systems

    Science.gov (United States)

    2011-12-01

    represents an indivisible unit of functionality, such as an EJB or CORBA component. A configuration is a valid composition of Features that produces a...Component-based middleware, such as the Lightweight CORBA Component Model, are increasingly used to implement large-scale distributed, real-time and...development, packaging, and deployment frameworks for a wide range of component middleware. Although originally developed for the CORBA Component Model

  17. Implementing Network Common Data Form (netCDF) for the 3DWF Model

    Science.gov (United States)

    2016-02-01

    findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents...12 Fig. 6 Illustration of grid’s AGL heights in a small portion of a cross section along the x-z axis (shown...Research Laboratory’s (ARL) Three-dimensional Wind Field (3DWF) model and its Graphical User Interface (GUI) to allow the model to use and to generate

  18. Design and analysis of a Petri net model of the Von Hippel-Lindau (VHL tumor suppressor interaction network.

    Directory of Open Access Journals (Sweden)

    Giovanni Minervini

    Full Text Available Von Hippel-Lindau (VHL syndrome is a hereditary condition predisposing to the development of different cancer forms, related to germline inactivation of the homonymous tumor suppressor pVHL. The best characterized function of pVHL is the ubiquitination dependent degradation of Hypoxia Inducible Factor (HIF via the proteasome. It is also involved in several cellular pathways acting as a molecular hub and interacting with more than 200 different proteins. Molecular details of pVHL plasticity remain in large part unknown. Here, we present a novel manually curated Petri Net (PN model of the main pVHL functional pathways. The model was built using functional information derived from the literature. It includes all major pVHL functions and is able to credibly reproduce VHL syndrome at the molecular level. The reliability of the PN model also allowed in silico knockout experiments, driven by previous model analysis. Interestingly, PN analysis suggests that the variability of different VHL manifestations is correlated with the concomitant inactivation of different metabolic pathways.

  19. Study of Multi-source Fusion B2C Business Process Reengineering of the Petri net Model

    Directory of Open Access Journals (Sweden)

    Feng Tian

    2013-11-01

    Full Text Available In order to fuse a multi-source B2C E-commerce system, this paper implements a new multi-source fusion B2C mode business system application development, which can provide customers with efficient and reliable comparison and cross-platform business system of choose and buy goods. By analyzing the Multi-source fusion B2C E-commerce system demand of business process reengineering and Petri net theory, the B2C electronic commerce system of multi-source fusion structure is proposed, graphical workflow modeling methods is adopted, the multi-source fusion of B2C business process reengineering Petri model is established, with the help of CPNtool simulation system and the establishment of correlation matrix analysis of the model. The experimental simulation analysis and output of experimental reports indicate that the business processes are properly designed, no deadlocks node exist at runtime, accessibility meets which provides the reference model for the development of multi-source fusion of B2C electronic commerce system.    

  20. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealized model applied to the Yangtze Estuary

    NARCIS (Netherlands)

    Alebregtse, N. C.|info:eu-repo/dai/nl/345704304; de Swart, H. E.|info:eu-repo/dai/nl/073449725

    2016-01-01

    Tidal propagation in, and division of net water transport over different channels in an estuarine network are analyzed using a newly developed idealized model. The water motion in this model is governed by the cross-sectionally averaged shallow water equations and is forced by tides at the seaward b

  1. Developing Inventory Projection Models Using Empirical Net Forest Growth and Growing-Stock Density Relationships Across U.S. Regions and Species Group

    Science.gov (United States)

    Prakash Nepal; Peter J. Ince; Kenneth E. Skog; Sun J. Chang

    2012-01-01

    This paper describes a set of empirical net forest growth models based on forest growing-stock density relationships for three U.S. regions (North, South, and West) and two species groups (softwoods and hardwoods) at the regional aggregate level. The growth models accurately predict historical U.S. timber inventory trends when we incorporate historical timber harvests...

  2. NetDiff - Bayesian model selection for differential gene regulatory network inference.

    Science.gov (United States)

    Thorne, Thomas

    2016-12-16

    Differential networks allow us to better understand the changes in cellular processes that are exhibited in conditions of interest, identifying variations in gene regulation or protein interaction between, for example, cases and controls, or in response to external stimuli. Here we present a novel methodology for the inference of differential gene regulatory networks from gene expression microarray data. Specifically we apply a Bayesian model selection approach to compare models of conserved and varying network structure, and use Gaussian graphical models to represent the network structures. We apply a variational inference approach to the learning of Gaussian graphical models of gene regulatory networks, that enables us to perform Bayesian model selection that is significantly more computationally efficient than Markov Chain Monte Carlo approaches. Our method is demonstrated to be more robust than independent analysis of data from multiple conditions when applied to synthetic network data, generating fewer false positive predictions of differential edges. We demonstrate the utility of our approach on real world gene expression microarray data by applying it to existing data from amyotrophic lateral sclerosis cases with and without mutations in C9orf72, and controls, where we are able to identify differential network interactions for further investigation.

  3. A reactive transport model for the geochemical response, detection and potential mitigation of CO2 leakage into a confined aquifer

    Science.gov (United States)

    Maher, K.; Druhan, J. L.; Vialle, S.; Benson, S. M.; Agarwal, A.

    2013-12-01

    Long-term storage of anthropogenic CO2 in the subsurface generally assumes that caprock formations will serve as physical barriers to upward migration of CO2. Stability and coherence of the caprocks are thus important criteria for site selection, but caprock integritycannot be guaranteed with total certainty over the lifetime of the project. As a result, carbon capture and storage projects require reliable techniques to monitor geologic storage sites for newly formed leaks, and the ability to rapidly deploy mitigation measures should leakage occur. Here, we present two-dimensional reactive transport simulations to evaluate the hydrogeochemical characteristics of a newly formed CO2 leak into an overlying reservoir. Simulations use the ToughReact multi-component reactive transport code and hypothetical reservoir characteristics. We focus on the comparatively short time period of days to months following formation of the leak to consider (1) geochemical shifts in formation water indicative of the leak, (2) hydrodynamics of pumping wells in the vicinity of the leak, and (3) delivery of a sealant to the leak through an adjacent well bore. Our results suggest that characteristic shifts in pH and dissolved inorganic carbon might be detected in down-gradient mentoring wells prior to the breakthrough of CO2, and could offer a potential means of identifying small and newly formed leaks. Injecting water into the aquifer through pumping wells in the vicinity of the leak provides a hydrodynamic control that can prevent CO2 from reaching the top of the reservoir, but this action will likely have only minor influence on the rate of leakage through the caprock defect. Injection of a hypothetical sealant through an adjacent pumping well is considered using an aqueous solute with pH-dependent equilibrium constraints such that the species is soluble in the basic pH range but forms a precipitate at neutral to acidic pH conditions associated with CO2-rich water. Injection of this

  4. Estimating Net Primary Production of Swedish Forest Landscapes by Combining Mechanistic Modeling and Remote Sensing

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Smith, Benjamin; Løfgren, Anders;

    2009-01-01

    The aim of this study was to investigate a combination of satellite images of leaf area index (LAI) with processbased vegetation modeling for the accurate assessment of the carbon balances of Swedish forest ecosystems at the scale of a landscape. Monthly climatologic data were used as inputs in a...

  5. Development of an RMS Model based on Colored Object-Oriented Petri Nets with Changeable Structures

    NARCIS (Netherlands)

    Zhang, Linda L.; Ittoo, Ashwin; Qi, ES; Cheng, G; Shen, JA; Dou, RL

    2009-01-01

    Current research on reconfigurable manufacturing systems (RMSs) only highlights the isolated empirical study with a limited attempt to explore the modeling and design support issues surrounding this economically important class of system development problems. This paper proposes colored object-orien

  6. ScaleNet: A literature-based model of scale insect biology and systematics

    Science.gov (United States)

    Scale insects (Hemiptera: Coccoidea) are small herbivorous insects found in all continents except Antarctica. They are extremely invasive, and many species are serious agricultural pests. They are also emerging models for studies of the evolution of genetic systems, endosymbiosis, and plant-insect i...

  7. Net Influence of an Internally Generated Guasi-biennial Oscillation on Modelled Stratospheric Climate and Chemistry

    Science.gov (United States)

    Hurwitz, Margaret M.; Oman, Luke David; Newman, Paul A.; Song, InSun

    2013-01-01

    A Goddard Earth Observing System Chemistry- Climate Model (GEOSCCM) simulation with strong tropical non-orographic gravity wave drag (GWD) is compared to an otherwise identical simulation with near-zero tropical non-orographic GWD. The GEOSCCM generates a quasibiennial oscillation (QBO) zonal wind signal in response to a tropical peak in GWD that resembles the zonal and climatological mean precipitation field. The modelled QBO has a frequency and amplitude that closely resembles observations. As expected, the modelled QBO improves the simulation of tropical zonal winds and enhances tropical and subtropical stratospheric variability. Also, inclusion of the QBO slows the meridional overturning circulation, resulting in a generally older stratospheric mean age of air. Slowing of the overturning circulation, changes in stratospheric temperature and enhanced subtropical mixing all affect the annual mean distributions of ozone, methane and nitrous oxide. Furthermore, the modelled QBO enhances polar stratospheric variability in winter. Because tropical zonal winds are easterly in the simulation without a QBO, there is a relative increase in tropical zonal winds in the simulation with a QBO. Extratropical differences between the simulations with and without a QBO thus reflect the westerly shift in tropical zonal winds: a relative strengthening of the polar stratospheric jet, polar stratospheric cooling and a weak reduction in Arctic lower stratospheric ozone.

  8. A high resolution 3D velocity model beneath the Tokyo Metropolitan area by MeSO-net

    Science.gov (United States)

    Nakagawa, S.; Sakai, S.; Honda, R.; Kimura, H.; Hirata, N.

    2015-12-01

    Beneath the Tokyo metropolitan area, the Philippine Sea Plate (PSP) subducts and causes devastating mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9). An M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating serious loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that an M7+ earthquake will cause 23,000 fatalities and 95 trillion yen (about 1 trillion US$) economic loss. We have launched the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters in collaboration with scientists, engineers, and social-scientists in nationwide institutions since 2012. We analyze data from the dense seismic array called Metropolitan Seismic Observation network (MeSO-net), which has 296 seismic stations with spacing of 5 km (Sakai and Hirata, 2009; Kasahara et al., 2009). We applied the double-difference tomography method (Zhang and Thurber, 2003) and estimated the velocity structure and the upper boundary of PSP (Nakagawa et al., 2010). The 2011 Tohoku-oki earthquake (M9.0) has activated seismicity also in Kanto region, providing better coverage of ray paths for tomographic analysis. We obtain much higher resolution velocity models from whole dataset observed by MeSO-net between 2008 and 2015. A detailed image of tomograms shows that PSP contacts Pacific plate at a depth of 50 km beneath northern Tokyo bay. A variation of velocity along the oceanic crust suggests dehydration reaction to produce seismicity in a slab, which may related to the M7+ earthquake. Acknowledgement: This study was supported by the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters of MEXT, Japan and the Earthquake Research Institute cooperative research program.

  9. Linear Logic on Petri Nets

    DEFF Research Database (Denmark)

    Engberg, Uffe Henrik; Winskel, Glynn

    This article shows how individual Petri nets form models of Girard's intuitionistic linear logic. It explores questions of expressiveness and completeness of linear logic with respect to this interpretation. An aim is to use Petri nets to give an understanding of linear logic and give some apprai...

  10. Spatial models for the rational allocation of routinely distributed bed nets to public health facilities in Western Kenya.

    Science.gov (United States)

    Macharia, Peter M; Odera, Patroba A; Snow, Robert W; Noor, Abdisalan M

    2017-09-12

    In high to moderate malaria transmission areas of Kenya, long-lasting insecticidal nets (LLINs) are provided free of charge to pregnant women and infants during routine antenatal care (ANC) and immunization respectively. Quantities of LLINs distributed to clinics are quantified based on a combination of monthly consumption data and population size of target counties. However, this approach has been shown to lead to stock-outs in targeted clinics. In this study, a novel LLINs need quantification approach for clinics in the routine distribution system was developed. The estimated need was then compared to the actual allocation to identify potential areas of LLIN over- or under-allocation in the high malaria transmission areas of Western Kenya. A geocoded database of public health facilities was developed and linked to monthly LLIN allocation. A network analysis approach was implemented using the location of all public clinics and topographic layers to model travel time. Estimated travel time, socio-economic and ANC attendance data were used to model clinic catchment areas and the probability of ANC service use within these catchments. These were used to define the number of catchment population who were likely to use these clinics for the year 2015 equivalent to LLIN need. Actual LLIN allocation was compared with the estimated need. Clinics were then classified based on whether allocation matched with the need, and if not, whether they were over or under-allocated. 888 (70%) public health facilities were allocated 591,880 LLINs in 2015. Approximately 682,377 (93%) pregnant women and infants were likely to have attended an LLIN clinic. 36% of the clinics had more LLIN than was needed (over-allocated) while 43% had received less (under-allocated). Increasing efficiency of allocation by diverting over supply of LLIN to clinics with less stock and fully covering 43 clinics that did not receive nets in 2015 would allow for complete matching of need with distribution. The

  11. F-Nets and Software Cabling: Deriving a Formal Model and Language for Portable Parallel Programming

    Science.gov (United States)

    DiNucci, David C.; Saini, Subhash (Technical Monitor)

    1998-01-01

    Parallel programming is still being based upon antiquated sequence-based definitions of the terms "algorithm" and "computation", resulting in programs which are architecture dependent and difficult to design and analyze. By focusing on obstacles inherent in existing practice, a more portable model is derived here, which is then formalized into a model called Soviets which utilizes a combination of imperative and functional styles. This formalization suggests more general notions of algorithm and computation, as well as insights into the meaning of structured programming in a parallel setting. To illustrate how these principles can be applied, a very-high-level graphical architecture-independent parallel language, called Software Cabling, is described, with many of the features normally expected from today's computer languages (e.g. data abstraction, data parallelism, and object-based programming constructs).

  12. A Stochastic Net Model for Controlling Bullwhip Effect in Virtual Multi-Tier Retail Network

    CERN Document Server

    Sarkar, Bidyut Biman; Chaki, Nabendu

    2011-01-01

    Supply Chain operation is an integrated business process starting from primary supplier to end user and the process produce products, services and information. A successful chain will explore technology, lean operations, and quality management by adding value for customers and stakeholders. It is a strategic alliance among the partnering enterprises without geographical boundary. Every chain has its own unique set of market demands and operating challenges. Retailing is one such service domain of Supply Chain vulnerable to bullwhip effects. Demand uncertainty is one of the root causes of Bullwhip effects. This paper calls for modeling of a demand driven multi-tier stochastic Retail Chain to work against the Bullwhip effect. The proposed model of the operational chain will ensure significant return of share to the retailer through the sophisticated transaction management, real-time inventory management and the ability to track all inventory movements.

  13. NCEP and GISS solar radiation data sets available for ecosystem modeling: Description, differences, and impacts on net primary production

    Science.gov (United States)

    Hicke, Jeffrey A.

    2005-06-01

    Downwelling surface solar radiation is an important input to ecosystem models, and global models require spatially extensive data sets that vary interannually to capture effects that potentially drive changes in ecosystem function. In this paper, I describe and compare solar radiation data sets from two representative sources, National Centers for Environmental Prediction (NCEP) reanalyses and Goddard Institute for Space Studies (GISS) calculations that included satellite observations of cloud properties. The CASA ecosystem model, which uses solar radiation and satellite-derived vegetation information, was run with the two solar radiation data sets to explore how differences affect estimated net primary production (NPP). GISS solar radiation matched ground-based observations better than NCEP solar radiation. Mean global NCEP solar radiation exceeded that from GISS by 16%, likely as a result of lower cloudiness within the NCEP reanalyses compared to satellite observations. Neither data set resulted in a significant trend over the study period (1984-2000). Locally, relative differences were up to 40% in the mean and 10% in the trend of solar radiation and NPP, and varied in sign across the globe. Because reanalysis solar radiation is only indirectly constrained by observations in contrast to the satellite-derived data, it is recommended that studies use the GISS solar radiation when possible.

  14. Modeled dosage-response relationship on the net photosynthetic rate for the sensitivity to acid rain of 21 plant species.

    Science.gov (United States)

    Deng, Shihuai; Gou, Shuzhen; Sun, Baiye; Lv, Wenlin; Li, Yuanwei; Peng, Hong; Xiao, Hong; Yang, Gang; Wang, Yingjun

    2012-08-01

    This study investigated the sensitivity of plant species to acid rain based on the modeled dosage-response relationship on the net photosynthetic rate (P (N)) of 21 types of plant species, subjected to the exposure of simulated acid rain (SAR) for 5 times during a period of 50 days. Variable responses of P (N) to SAR occurred depending on the type of plant. A majority (13 species) of the dosage-response relationship could be described by an S-shaped curve and be fitted with the Boltzmann model. Model fitting allowed quantitative evaluation of the dosage-response relationship and an accurate estimation of the EC(10), termed as the pH of the acid rain resulting in a P (N) 10 % lower than the reference value. The top 9 species (Camellia sasanqua, Cinnamomum camphora, etc. EC(10) ≤ 3.0) are highly endurable to very acid rain. The rare, relict plant Metasequoia glyptostroboides was the most sensitive species (EC(10) = 5.1) recommended for protection.

  15. Net Proton Flow and Nuclear Transparency Effects at RHIC : A Multiple Fireball Model approach

    CERN Document Server

    Uddin, Saeed; Shabir, Jan; Mir, M Farooq

    2009-01-01

    Recently Beccattini and Cleymamns have proposed a model to understand the p-pbar data obtained at RHIC and SPS. We have shown that this model has a much greater applicability and can very well be used to describe the rapidity spectra of protons and antiprotons separately measured at the highest energy of Relativistic Heavy Ion Collider i.e., 200 GeV/A by BRAHMS Collaboration. We have also determined that the contribution of the decay products of the heavier resonances like delta, lambda etc. actually dominate over the protons (antiprotons) of pure thermal origin. We have also imposed the criteria of exact strangeness conservation in each fireball separately. It is shown that it is possible to explain not only the p-pbar data but the complete set of data viz. the rapidity distributions of protons, antiprotons and the ratio pbar/p simultaneously quite well with a single set of model parameters which includes a single value of the temperature parameter T chosen for all the fireballs. We have also fitted the Kaon...

  16. The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model

    Science.gov (United States)

    Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.

    2004-01-01

    We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

  17. The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model

    Science.gov (United States)

    Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.

    2004-01-01

    We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

  18. Petri Net-Based Model of Helicobacter pylori Mediated Disruption of Tight Junction Proteins in Stomach Lining during Gastric Carcinoma

    Directory of Open Access Journals (Sweden)

    Anam Naz

    2017-09-01

    Full Text Available Tight junctions help prevent the passage of digestive enzymes and microorganisms through the space between adjacent epithelial cells lining. However, Helicobacter pylori encoded virulence factors negatively regulate these tight junctions and contribute to dysfunction of gastric mucosa. Here, we have predicted the regulation of important tight junction proteins, such as Zonula occludens-1, Claudin-2 and Connexin32 in the presence of pathogenic proteins. Molecular events such as post translational modifications and crosstalk between phosphorylation, O-glycosylation, palmitoylation and methylation are explored which may compromise the integrity of these tight junction proteins. Furthermore, the signaling pathways disrupted by dysregulated kinases, proteins and post-translational modifications are reviewed to design an abstracted computational model showing the situation-dependent dynamic behaviors of these biological processes and entities. A qualitative hybrid Petri Net model is therefore constructed showing the altered host pathways in the presence of virulence factor cytotoxin-associated gene A, leading to the disruption of tight junction proteins. The model is qualitative logic-based, which does not depend on any kinetic parameter and quantitative data and depends on knowledge derived from experiments. The designed model provides insights into the tight junction disruption and disease progression. Model is then verified by the available experimental data, nevertheless formal in vitro experimentation is a promising way to ensure its validation. The major findings propose that H. pylori activated kinases are responsible to trigger specific post translational modifications within tight junction proteins, at specific sites. These modifications may favor alterations in gastric barrier and provide a route to bacterial invasion into host cells.

  19. Effects of ozone on net primary production and carbon sequestration in the conterminous United States using a biogeochemistry model

    Science.gov (United States)

    Felzer, B.; Kicklighter, D.; Melillo, J.; Wang, C.; Zhuang, Q.; Prinn, R.

    2004-07-01

    The effects of air pollution on vegetation may provide an important control on the carbon cycle that has not yet been widely considered. Prolonged exposure to high levels of ozone, in particular, has been observed to inhibit photosynthesis by direct cellular damage within the leaves and through possible changes in stomatal conductance. We have incorporated empirical equations derived for trees (hardwoods and pines) and crops into the Terrestrial Ecosystem Model to explore the effects of ozone on net primary production (NPP) and carbon sequestration across the conterminous United States. Our results show a 2.6 6.8% mean reduction for the United States in annual NPP in response to modelled historical ozone levels during the late 1980s-early 1990s. The largest decreases (over 13% in some locations) occur in the Midwest agricultural lands, during the mid-summer when ozone levels are highest. Carbon sequestration since the 1950s has been reduced by 18 38 Tg C yr1 with the presence of ozone. Thus the effects of ozone on NPP and carbon sequestration should be factored into future calculations of the United States' carbon budget.

  20. Modeling the impact of net primary production dynamics on post-disturbance Amazon savannization

    Directory of Open Access Journals (Sweden)

    MÔNICA C.A. SENNA

    2014-06-01

    Full Text Available Amazon tropical forests are being replaced by pasturelands and croplands, but they sometimes revert to regrowth forest when abandoned after a period of agricultural use. Research suggests that this secondary regrowth is limited by climate and nutrient availability and, using a coupled biosphere-atmosphere model, we investigated patterns in the regrowth of the Amazon rainforest after a full deforestation event, considering different types of nutrient stress. We found that, over a 50 year regrowth period, the reduction of precipitation caused by large-scale deforestation was not sufficient to prevent secondary forest regrowth, but this decrease in precipitation combined with nutrient limitation, due to logging and frequent fires, did indeed prevent forest regrowth in central and southern Amazonia, leading to a savannization. These results are concerning, as the northern Mato Grosso region has the highest clearing rate in Amazonia. The low resilience of the forest under nutrient stress indicates that a large scale disturbance could greatly expand the area suitable for cropland, accelerating forest disappearance.

  1. YAWL到BPMN的映射研究%From YAWL Nets to BPMN Models

    Institute of Scientific and Technical Information of China (English)

    叶双; 叶剑虹; 宋文; 孙世新

    2011-01-01

    针对YAWL语言目前存在较多OR逻辑二义性的情况,提出将YAWL转换成BPMN语言.转换不仅可以解决YAWL在多实例、同步和取消等模式表达上存在的不足,转换后更为简洁的BPMN模型也有利于进一步性质分析.算法的最终实现已嵌入到最新的ProM5.2平台中.%According to the ambiguous OR syntaxes of YAWL,a mapping algorithm from YAWL to BPMN is presented in this paper. Some patterns (e. G. Involving multiple instances,complex synchronizations or non-local withdrawals) which are not easy showed by YAWL can be presented on BPMN diagrams. The transformation benefits the analysis of model because the deployment of BPMN is simplified. A mapping algorithm plug-in is integrated in open-source process mining framework named ProM 5. 2.

  2. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealised model applied to the Yangtze Estuary

    Science.gov (United States)

    de Swart, Huib E.; Alebregtse, Niels C.

    2015-04-01

    Many estuaries in the world show a complex pattern of interconnected branches. The water motion in these estuarine networks is dominated by tides and by net water transport, the latter being primarily forced by river discharge and by nonlinear tidal rectification processes. The behaviour of tides (sea surface height and currents) and the distribution of net water transport over the branches is an important topic of research, e.g. for flushing of pollutants, salinity intrusion and sediment transport. Field observations, e.g. in the Yangtze Estuary, show that tides and distribution of net water transport over the branches are highly sensitive to river discharge (wet and dry season) and to changes in geometry, e.g. due to navigational works. To understand such sensivities, this contribution presents a semi-analytical model that yields explicit solutions for tides and net water transport for arbitrary tidal network configurations. The model accounts for tide-river interactions, which in particular affect friction, and for tidal rectification processes. The model is subsequently applied to the Yangtze Estuary. It will be shown that tide-river interactions are crucial to understand the observed differences in tidal propagation between the wet and dry season. Furthermore, the relative increase of the net water transport driven by tidal rectification with respect to that driven by river discharge explains the observed differences in distribution of water transport over the branches between wet and dry season in this estuary. Finally, it will be shown that the construction of navigational works resulted in an increase of tidal currents, a decrease of net water transport and an increase in ebb-dominance in the North Passage of the Yangtze Estuary, consistent with observations.

  3. Modeling the significance of including C redistribution when determining changes in net carbon storage along a cultivated toposequence

    Science.gov (United States)

    Chirinda, Ngonidzashe; Olesen, Jørgen E.; Heckrath, Goswin; Paradelo Pérez, Marcos; Taghizadeh-Toosi, Arezoo

    2016-04-01

    Globally, soil carbon (C) reserves are second only to those in the ocean, and accounts for a significant C reservoir. In the case of arable soils, the quantity of stored C is influenced by various factors (e.g. management practices). Currently, the topography related influences on in-field soil C dynamics remain largely unknown. However, topography is known to influence a multiplicity of factors that regulate C input, storage and redistribution. To understand the patterns and untangle the complexity of soil C dynamics in arable landscapes, our study was conducted with soils from shoulderslope and footslope positions on a 7.1 ha winter wheat field in western Denmark. We first collected soil samples from shoulderslope and footslope positions with various depth intervals down to 100 cm and analyzed them for physical and chemical properties including texture and soil organic C contents. In-situ carbon dioxide (CO2) concentrations were measured at different soil profile depths at both positions for a year. Soil moisture content and temperature at 5 and 40 cm depth was measured continuously. Additionally, surface soil CO2 fluxes at shoulderslope and footslope positions were measured. We then used measurement data collected from the two landscape positions to calibrate the one-dimensional mechanistic model SOILCO2 module of the HYDRUS-1D software package and obtained soil CO2 fluxes from soil profile at two landscape positions. Furthermore, we tested whether the inclusion of vertical and lateral soil C movement improved the modeling of C dynamics in cultivated landscapes. For that, soil profile CO2 fluxes were compared with those obtained using a simple process-based soil whole profile C model, C-TOOL, which was modified to include vertical and lateral movement of C on landscape. Our results highlight the need to consider vertical and lateral soil C movement in the modeling of C dynamics in cultivated landscapes, for better qualification of net carbon storage.

  4. Modeling the Metabolism of Arabidopsis thaliana: Application of Network Decomposition and Network Reduction in the Context of Petri Nets

    Directory of Open Access Journals (Sweden)

    Ina Koch

    2017-06-01

    Full Text Available Motivation:Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. Nevertheless, the system is not yet fully understood, although many mechanisms are described, and information for many processes exists. However, the combination and interpretation of the large amount of biological data remain a big challenge, not only because data sets for metabolic paths are still incomplete. Moreover, they are often inconsistent, because they are coming from different experiments of various scales, regarding, for example, accuracy and/or significance. Here, theoretical modeling is powerful to formulate hypotheses for pathways and the dynamics of the metabolism, even if the biological data are incomplete. To develop reliable mathematical models they have to be proven for consistency. This is still a challenging task because many verification techniques fail already for middle-sized models. Consequently, new methods, like decomposition methods or reduction approaches, are developed to circumvent this problem.Methods: We present a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. We used the Petri net formalism to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency we applied concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs.Results: We formulated the core metabolism of Arabidopsis thaliana based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism. By applying network decomposition and reduction techniques at steady-state conditions, we suggest a straightforward mathematical modeling process. We demonstrate that potential steady-state pathways exist, which provide the

  5. Time Petri Net Model with Mixed Semantics%混合语义时间Petri网模型

    Institute of Scientific and Technical Information of China (English)

    潘理; 丁志军; 郭观七

    2011-01-01

    提出了时间Petri网的混合语义模型,通过在变迁及其非冲突变迁集的最小上界处设置强制实施点,排除冲突变迁对变迁可实施性的影响,达到既能扩大模型调度范围又可保证任务调度时限性的目的,以解决现有语义模型在调度分析上的缺陷.进一步证明了混合语义模型的图灵等价性及标识可达性问题的不可判定性,然后界定了3种语义模型的时间语言接受能力.最后提出了状态类分析方法,用于模型的可调度性分析和时间计算,并以一个柔性制造系统为例,比较和验证了3种语义模型的调度分析能力.%This paper presents a time Petri net (TPN) model with mixed semantics that efficiently addresses the schedulability analysis problem of the existing semantics models. The proposed model associates each firahle transition with a mandatory firing point that is set to the least upper bound of the transition and its non-conflicting transitions. This treatment not only eliminates the effect of conflicting transitions on the transition friability and extends the scheduling scope of the TPN model, but also ensures the time limit of thc task scheduling. To determine thc exprcssiveness of the mixed model, the study proves that the mixed semantics model has the power of Turing machines and its marking reachability problem is undecidable. The timed expressiveness of three semantics models with respect to timed language acceptance is also comparcd. A statc class approach is then proposed for the scheduling analysis of thc mixed model. Finally, a flexible manufacturing system is used as an example to compare the scheduling ability of three semantics models.

  6. The flotation tailings of the former Pb-Zn mine of Touiref (NW Tunisia): mineralogy, mine drainage prediction, base-metal speciation assessment and geochemical modeling.

    Science.gov (United States)

    Othmani, Mohamed Ali; Souissi, Fouad; Bouzahzah, Hassan; Bussière, Bruno; da Silva, Eduardo Ferreira; Benzaazoua, Mostafa

    2015-02-01

    The underground extraction of Pb-Zn mineralization in the Touiref area stopped in 1958. A large volume of flotation tailings (more than 500 Mt) containing sulfides were deposited in a tailings impoundment. The goals of this study are to evaluate the neutralization capacity of the unoxidized and oxidized tailings, to assess the speciation of metals between the different components of the tailings material, and to assess the mobility of metals and the secondary minerals' precipitation in pore waters using geochemical modeling. To accomplish these objectives, representative samples from both fresh and oxidized zones were collected along a vertical profile through the tailings pile. Physical, chemical (ICP-MS), and mineralogical characterization (X-ray diffraction (XRD), reflected light microscopy, scanning electron microscope (SEM)) of these samples was performed. Grain size analysis shows that the tailings are dominated by silt- to sand-sized fractions. The microscopic observation highlights the presence of pyrite, marcasite, galena, and sphalerite as primary minerals in a carbonated matrix. The study reveals also the presence of secondary minerals represented by cerussite, smithsonite, anglesite, and Fe oxi-hydroxides as important scavengers for trace elements. The static tests show that the presence of calcite in the tailing samples ensures acid-neutralizing capacity (ANC), which is significantly greater than the acidity potential (PA). The geochemical characterization of the unoxidized samples shows higher Cd, Pb, and Zn concentrations than the oxidized samples containing the highest values for Fe and SO4. Sequential extraction tests show that significant percentages of metals are distributed between the acid-soluble fractions (Cd, Pb, and Zn) and the reducible one (Zn). Pore water analysis indicates that Ca is the dominant cation (8,170 and 6,200 mg L(-1), respectively), whereas sulfate is the principal anion (6,900 and 5,100 mg L(-1), respectively). Saturation

  7. Inverse Geochemical Reaction Path Modelling and the Impact of Climate Change on Hydrologic Structure in Snowmelt-Dominated Catchments in the Southwestern USA

    Science.gov (United States)

    Driscoll, J. M.; Meixner, T.; Molotch, N. P.; Sickman, J. O.; Williams, M. W.; McIntosh, J. C.; Brooks, P. D.

    2011-12-01

    Snowmelt from alpine catchments provides 70-80% of the American Southwest's water resources. Climate change threatens to alter the timing and duration of snowmelt in high elevation catchments, which may also impact the quantity and the quality of these water resources. Modelling of these systems provides a robust theoretical framework to process the information extracted from the sparse physical measurement available in these sites due to their remote locations. Mass-balance inverse geochemical models (via PHREEQC, developed by the USGS) were applied to two snowmelt-dominated catchments; Green Lake 4 (GL4) in the Rockies and Emerald Lake (EMD) in the Sierra Nevada. Both catchments primarily consist of granite and granodiorite with a similar bulk geochemistry. The inputs for the models were the initial (snowpack) and final (catchment output) hydrochemistry and a catchment-specific suite of mineral weathering reactions. Models were run for wet and dry snow years, for early and late time periods (defined hydrologically as 1/2 of the total volume for the year). Multiple model solutions were reduced to a representative suite of reactions by choosing the model solution with the fewest phases and least overall phase change. The dominant weathering reactions (those which contributed the most solutes) were plagioclase for GL4 and albite for EMD. Results for GL4 show overall more plagioclase weathering during the dry year (214.2g) than wet year (89.9g). Both wet and dry years show more weathering in the early time periods (63% and 56%, respectively). These results show that the snowpack and outlet are chemically more similar during wet years than dry years. A possible hypothesis to explain this difference is a change in contribution from subsurface storage; during the wet year the saturated catchment reduces contact with surface materials that would result in mineral weathering reactions by some combination of reduced infiltration and decreased subsurface transit time. By

  8. MagNet中参数化建模程序开发%Development of Parametric Modeling Program in MagNet

    Institute of Scientific and Technical Information of China (English)

    侯义明; 黄英晓

    2012-01-01

    介绍了在Excel软件环境下,利用VBA编程,在MagNet软件环境中自动建立3D仿真模型的程序开发方法。%The developing method to establish 3D simulation model automatically in Mag- Net under Excell with VBA is presented.

  9. Uranium transport around the reactor zone at Bangombé and Okélobondo (Oklo): examples of hydrogeological and geochemical model integration and data evaluation

    Science.gov (United States)

    Gurban, I.; Laaksoharju, M.; Madé, B.; Ledoux, E.

    2003-03-01

    The sites at Bangombé and Okélobondo (Oklo) in Gabon provide a unique opportunity to study the behaviour of products from natural nuclear reactions in the vicinity of reactor zones which were active around two billion years ago. The Commission of the European Communities initiated the Oklo Natural Analogue Programme. One of the principal aims was to study indications of present time migration of elements from the reactor zones under ambient conditions. The hydrogeological and hydrochemical data from the Oklo sites were modelled in order to better understand the geochemical behaviour of radionuclides in the natural system, by using independent models and by comparing the modelling outcome. Two modelling approaches were used: M3 code (hydrochemical mixing and mass balance model), developed by the Swedish Nuclear Fuel and Waste Management Company (SKB) and HYTEC (reactive transport model) developed by Ecole des Mines de Paris. Two different reactor zones were studied: Bangombé, a shallow site, the reactor being at 11 m depth, and OK84 at Okélobondo, situated at about 450 m depth, more comparable with a real repository location. This allowed the validation of modelling tools in two different sedimentary environments: one shallow, with a more homogeneous layering situated in an area of meteoric alteration, and the other offering the opportunity to study radionuclide migration from the reaction zone over a distance of 450 m through very heterogeneous sedimentary layers. The modeling results indicate that the chemical reactions retarding radionuclide transport are very different at the two sites. At Bangombé, the decomposition of organic material consumes oxygen and at Okélobondo the oxygen is consumed by inorganic reactions resulting, in both cases, in uranium retardation. Both modelling approaches (statistic with M3 code and deterministic with HYTEC code) could describe this situation. The goal of this exercise is to test codes which can help to describe and

  10. Constraining Runoff Source Fraction Contributions from Alpine Glaciers through the Combined Application of Geochemical Proxies and Bayesian Monte Carlo Isotope Mixing Models

    Science.gov (United States)

    Arendt, C. A.; Aciego, S.; Hetland, E.

    2015-12-01

    glacial decline will make snowmelt the dominant water reservoir. Second, the calculated source fraction water volumes are a starting point for additional geochemical models to investigate water storage within the subglacial hydrological network.

  11. Brine Migration from a Flooded Salt Mine in the Genesee Valley, Livingston County, New York: Geochemical Modeling and Simulation of Variable-Density Flow

    Science.gov (United States)

    Yager, Richard M.; Misut, Paul E.; Langevin, Christian D.; Parkhurst, David L.

    2009-01-01

    The Retsof salt mine in upstate New York was flooded from 1994 to 1996 after two roof collapses created rubble chimneys in overlying bedrock that intersected a confined aquifer in glacial sediments. The mine now contains about 60 billion liters of saturated halite brine that is slowly being displaced as the weight of overlying sediments causes the mine cavity to close, a process that could last several hundred years. Saline water was detected in the confined aquifer in 2002, and a brine-mitigation project that includes pumping followed by onsite desalination was implemented in 2006 to prevent further migration of saline water from the collapse area. A study was conducted by the U.S. Geological Survey using geochemical and variable-density flow modeling to determine sources of salinity in the confined aquifer and to assess (1) processes that control movement and mixing of waters in the collapse area, (2) the effect of pumping on salinity, and (3) the potential for anhydrite dissolution and subsequent land subsidence resulting from mixing of waters induced by pumping. The primary source of salinity in the collapse area is halite brine that was displaced from the flooded mine and transported upward by advection and dispersion through the rubble chimneys and surrounding deformation zone. Geochemical and variable-density modeling indicate that salinity in the upper part of the collapse area is partly derived from inflow of saline water from bedrock fracture zones during water-level recovery (January 1996 through August 2006). The lateral diversion of brine into bedrock fracture zones promoted the upward migration of mine water through mixing with lower density waters. The relative contributions of mine water, bedrock water, and aquifer water to the observed salinity profile within the collapse area are controlled by the rates of flow to and from bedrock fracture zones. Variable-density simulations of water-level recovery indicate that saline water has probably not

  12. iMarNet: an ocean biogeochemistry model inter-comparison project within a common physical ocean modelling framework

    Directory of Open Access Journals (Sweden)

    L. Kwiatkowski

    2014-07-01

    Full Text Available Ocean biogeochemistry (OBGC models span a wide range of complexities from highly simplified, nutrient-restoring schemes, through nutrient-phytoplankton-zooplankton-detritus (NPZD models that crudely represent the marine biota, through to models that represent a broader trophic structure by grouping organisms as plankton functional types (PFT based on their biogeochemical role (Dynamic Green Ocean Models; DGOM and ecosystem models which group organisms by ecological function and trait. OBGC models are now integral components of Earth System Models (ESMs, but they compete for computing resources with higher resolution dynamical setups and with other components such as atmospheric chemistry and terrestrial vegetation schemes. As such, the choice of OBGC in ESMs needs to balance model complexity and realism alongside relative computing cost. Here, we present an inter-comparison of six OBGC models that were candidates for implementation within the next UK Earth System Model (UKESM1. The models cover a large range of biological complexity (from 7 to 57 tracers but all include representations of at least the nitrogen, carbon, alkalinity and oxygen cycles. Each OBGC model was coupled to the Nucleus for the European Modelling of the Ocean (NEMO ocean general circulation model (GCM, and results from physically identical hindcast simulations were compared. Model skill was evaluated for biogeochemical metrics of global-scale bulk properties using conventional statistical techniques. The computing cost of each model was also measured in standardised tests run at two resource levels. No model is shown to consistently outperform or underperform all other models across all metrics. Nonetheless, the simpler models that are easier to tune are broadly closer to observations across a number of fields, and thus offer a high-efficiency option for ESMs that prioritise high resolution climate dynamics. However, simpler models provide limited insight into more complex

  13. Petri net-based approach to modeling and analysis of selected aspects of the molecular regulation of angiogenesis

    Science.gov (United States)

    Formanowicz, Dorota; Radom, Marcin; Zawierucha, Piotr; Formanowicz, Piotr

    2017-01-01

    The functioning of both normal and pathological tissues depends on an adequate supply of oxygen through the blood vessels. A process called angiogenesis, in which new endothelial cells and smooth muscles interact with each other, forming new blood vessels either from the existing ones or from a primary vascular plexus, is particularly important and interesting, due to new therapeutic possibilities it offers. This is a multi-step and very complex process, so an accurate understanding of the underlying mechanisms is a significant task, especially in recent years, with the constantly increasing amount of new data that must be taken into account. A systems approach is necessary for these studies because it is not sufficient to analyze the properties of the building blocks separately and an analysis of the whole network of interactions is essential. This approach is based on building a mathematical model of the system, while the model is expressed in the formal language of a mathematical theory. Recently, the theory of Petri nets was shown to be especially promising for the modeling and analysis of biological phenomena. This analysis, based mainly on t-invariants, has led to a particularly important finding that a direct link (close connection) exist between transforming growth factor β1 (TGF-β1), endothelial nitric oxide synthase (eNOS), nitric oxide (NO), and hypoxia-inducible factor 1, the molecules that play a crucial roles during angiogenesis. We have shown that TGF-β1 may participate in the inhibition of angiogenesis through the upregulation of eNOS expression, which is responsible for catalyzing NO production. The results obtained in the previous studies, concerning the effects of NO on angiogenesis, have not been conclusive, and therefore, our study may contribute to a better understanding of this phenomenon. PMID:28253310

  14. Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

    Directory of Open Access Journals (Sweden)

    Chuanjiang Tang

    2014-01-01

    Full Text Available Net primary productivity (NPP is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR, light use efficiency (ε, and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

  15. A livelock control policy for a flexible manufacturing system modeling with a subclass of generalized Petri nets

    Directory of Open Access Journals (Sweden)

    C.Q. Hou

    2014-12-01

    Full Text Available Livelocks, like deadlocks, can result in the serious problems in running process of flexible manufacturing systems (FMSs as well. Current deadlock control policies based on the approaches of siphon detection and control, cannot cope with livelocks in a system of sequential systems with shared resources (S4R, a typical subclass of Petri nets that can model FMSs. On the basis of the mixed integer programming method, this study proposes a livelock control policy (LCP that can not only solve the new smart siphons (NSSs associated with livelocks or deadlocks in an S4R system directly, but also make the solved NSSs max′-controlled by adding the corresponding control places (CPs. As a result, an original S4R system with livelocks or deadlocks can be turned into the live controlled one in which no NSSs can be found. The related theoretical analysis and several examples are given to demonstrate the proposed LCP. Compared with the existing methods in the literature, the proposed one is more general and powerful.

  16. Imaging geochemical heterogeneities using inverse reactive transport modeling: An example relevant for characterizing arsenic mobilization and distribution

    DEFF Research Database (Denmark)

    Fakhreddine, Sarah; Lee, Jonghyun; Kitanidis, Peter K.

    2016-01-01

    -bearing reactive minerals as aquifer contaminants. We use synthetic applications to demonstrate the ability of inverse modeling techniques combined with mechanistic reactive transport models to image reactive mineral lenses in the subsurface and quantify estimation error using indirect, commonly measured...... such as managed aquifer recharge and recovery operations. The modeling investigation is carried out at various scales and considers different flow-through domains including (i) a ID lab-scale column (SO cm), (ii) a 2D lab-scale setup (60 cm x 30 cm) and (iii) a 2D field scale domain (20 nix 4 m). In these setups......, synthetic dissolved oxygen data and forward reactive transport simulations are used to image the spatial distribution of As-bearing pyrite using the Principal Component Geostatistical Approach (PCGA) for inverse modeling. (C) 2015 Elsevier Ltd. All rights reserved....

  17. Net community production of oxygen derived from in vitro and in situ 1-D modeling techniques in a cyclonic mesoscale eddy in the Sargasso Sea

    Directory of Open Access Journals (Sweden)

    B. Mouriño-Carballido

    2009-08-01

    Full Text Available It has been proposed that the disagreement traditionally reported between in vitro incubation and in situ estimates of oxygen net community production (NCP could be explained, at least partially, by undersampling episodic pulses of net autotrophy associated with mesoscale dynamics. In this study we compare in vitro incubation estimates of net community production with in situ estimates, derived from oxygen profiles and a 1-D model, within a cyclonic eddy investigated in the Sargasso Sea in summer 2004. The in vitro NCP rates measured at the center of the eddy showed a shift from net autotrophy (7±3 mmol O2 m−2 d−1 to net heterotrophy (−25±5 mmol O2 m−2 d−1 from late June to early August. The model-derived NCP rates also showed a temporal decline (19±6 to −3±7 and 11±8 mmol O2 m−2 d−1, but they were systematically higher than the in vitro estimates and reported net autotrophy or balance for the sampling period. In this comparison episodic pulses in photosynthesis or respiration driven by mesoscale eddies can not explain the discrepancy between the in vitro and in situ estimates of NCP. This points to methodological artefacts or temporal or submesoscale variability as the mechanisms responsible for the disagreement between the techniques, at least in this dataset.

  18. 生化网络的随机Petri网建模与分析%Modeling and analyzing biochemical networks using stochastic Petri nets

    Institute of Scientific and Technical Information of China (English)

    丁德武; 李文泽

    2012-01-01

    细胞的行为是随机性的,学习细胞中的随机性有助于理解细胞的组织,设计和进化.建立、确认和分析随机的生化网络模型是当前计算系统生物学领域的一个重要研究主题.当前,标准的Petri网模型已经成为生化网络模拟和定性分析的有力工具.尝试使用随机Petri网对生化网络进行建模与分析,简单描述了随机Petri网理论对标准Petri网的扩充,通过对二聚作用和肌动蛋白这两个典型例子的建模与演化模拟,介绍、论证了随机Petri网理论的新应用.%Cellular behavior is stochastic, and studying stochastic in the cell can help to understand the organization, design and evolution of the cell. Establishment, identification and analysis of stochastic biochemical network models is an important research topic in the field of computational systems biology. At present, the standard Petri net model has become a powerful tool for biochemical network modeling and qualitative analysis. This paper attempts to apply stochastic Petri nets to modeling and analyzing biochemical network, it briefly describes the expansion of the stochastic Petri net theory to standard Petri nets, then by modeling and evolution simulating two classic examples (dimerization and actin), it demonstrates new applications of stochastic Petri nets theory.

  19. Fluctuations and Correlations of net baryon number, electric charge, and strangeness: A comparison of lattice QCD results with the hadron resonance gas model

    CERN Document Server

    Bazavov, A; DeTar, C E; Ding, H -T; Gottlieb, Steven; Gupta, Rajan; Hegde, P; Heller, Urs; Karsch, F; Laermann, E; Levkova, L; Mukherjee, Swagato; Petreczky, P; Schmidt, Christian; Soltz, R A; Soeldner, W; Sugar, R; Vranas, Pavlos M

    2012-01-01

    We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results in the continuum limit are obtained using calculations with tree level improved gauge and the highly improved staggered quark (HISQ) actions with almost physical light and strange quark masses at three different values of the lattice cut-off. We compare our results with the hadron resonance gas (HRG) model calculations and find agreement with HRG model results only for temperatures T < 150 MeV. We observe significant deviations in the temperature range 160 MeV < T < 170 MeV and qualitative differences in the behavior of the three conserved charge sectors. At $T \\simeq 160 MeV$ quadratic net baryon number fluctuations in QCD agree with HRG model calculations while, the net electric charge fluctuations in QCD are about 10% smaller and net strangeness fluctuations are about 20% larger. These fin...

  20. Estimation of Ecosystem Parameters of the Community Land Model with DREAM: Evaluation of the Potential for Upscaling Net Ecosystem Exchange

    Science.gov (United States)

    Hendricks Franssen, H. J.; Post, H.; Vrugt, J. A.; Fox, A. M.; Baatz, R.; Kumbhar, P.; Vereecken, H.

    2015-12-01

    Estimation of net ecosystem exchange (NEE) by land surface models is strongly affected by uncertain ecosystem parameters and initial conditions. A possible approach is the estimation of plant functional type (PFT) specific parameters for sites with measurement data like NEE and application of the parameters at other sites with the same PFT and no measurements. This upscaling strategy was evaluated in this work for sites in Germany and France. Ecosystem parameters and initial conditions were estimated with NEE-time series of one year length, or a time series of only one season. The DREAM(zs) algorithm was used for the estimation of parameters and initial conditions. DREAM(zs) is not limited to Gaussian distributions and can condition to large time series of measurement data simultaneously. DREAM(zs) was used in combination with the Community Land Model (CLM) v4.5. Parameter estimates were evaluated by model predictions at the same site for an independent verification period. In addition, the parameter estimates were evaluated at other, independent sites situated >500km away with the same PFT. The main conclusions are: i) simulations with estimated parameters reproduced better the NEE measurement data in the verification periods, including the annual NEE-sum (23% improvement), annual NEE-cycle and average diurnal NEE course (error reduction by factor 1,6); ii) estimated parameters based on seasonal NEE-data outperformed estimated parameters based on yearly data; iii) in addition, those seasonal parameters were often also significantly different from their yearly equivalents; iv) estimated parameters were significantly different if initial conditions were estimated together with the parameters. We conclude that estimated PFT-specific parameters improve land surface model predictions significantly at independent verification sites and for independent verification periods so that their potential for upscaling is demonstrated. However, simulation results also indicate

  1. Modeling the geochemical distribution of rare earth elements (REEs using multivariate statistics in the eastern part of Marvast placer, the Yazd province

    Directory of Open Access Journals (Sweden)

    Amin Hossein Morshedy

    2017-07-01

    Full Text Available Introduction Nowadays, exploration of rare earth element (REE resources is considered as one of the strategic priorities, which has a special position in the advanced and intelligent industries (Castor and Hedrick, 2006. Significant resources of REEs are found in a wide range of geological settings, including primary deposits associated with igneous and hydrothermal processes (e.g. carbonatite, (per alkaline-igneous rocks, iron-oxide breccia complexes, scarns, fluorapatite veins and pegmatites, and secondary deposits concentrated by sedimentary processes and weathering (e.g. heavy-mineral sand deposits, fluviatile sandstones, unconformity-related uranium deposits, and lignites (Jaireth et al., 2014. Recent studies on various parts of Iran led to the identification of promising potential of these elements, including Central Iran, alkaline rocks in the Eslami Peninsula, iron and apatite in the Hormuz Island, Kahnouj titanium deposit, granitoid bodies in Yazd, Azerbaijan, and Mashhad and associated dikes, and finally placers related to the Shemshak formation in Marvast, Kharanagh, and Ardekan indicate high concentration of REE in magmatogenic iron–apatite deposits in Central Iran and placers in Marvast area in Yazd (Ghorbani, 2013. Materials and methods In the present study, the geochemical behavior of rare earth elements is modeled by using multivariate statistical methods in the eastern part of the Marvast placer. Marvast is located 185 km south of the city of Yazd in central Iran between Yazd and Mehriz. This area lies within the southeastern part of the Sanandaj-Sirjan Zone (Alipour-Asll et al., 2012. The samples of 53 wells were analyzed for Whole-rock trace-element concentrations (including REE by inductively coupled plasma-mass spectrometry (ICP-MS (GSI, 2004. The clustering techniques such as multivariate statistical analysis technique can be employed to find appropriate groups in data sets. One of the main objectives of data clustering

  2. Modeling of Carbon Sequestration on Eucalyptus Plantation in Brazililian Cerrado Region for Better Characterization of Net Primary Productivity

    Science.gov (United States)

    Echeverri, J. D.; Siqueira, M. B.

    2013-05-01

    Managed Forests have important roles in climate change due to their contribution to CO2 sequestration stored in their biomass, soils and products therefrom. Terrestrial net primary production (NPP, kgC/m2), equal to gross primary production minus autotrophic respiration, represents the carbon available for plant allocation to leaves, stems, roots, defensive compounds, and reproduction and is the basic measure of biological productivity. Tree growth, food production, fossil fuel production, and atmospheric CO2 levels are all strongly controlled by NPP. Accurate quantification of NPP at local to global scales is therefore central topic for carbon cycle researchers, foresters, land and resource managers, and politicians. For recent or current NPP estimates, satellite remote sensing can be used but for future climate scenarios, simulation models are required. There is an increasing trend to displace natural Brazilian Cerrado to Eucalyptus for paper mills and energy conversion from biomass. The objective of this research exercise is to characterize NPP from managed Eucalyptus plantation in the Brazilian Cerrado. The models selected for this study were the 3-PG and Biome-BGC. The selection of these models aims to cover a range of complexity that allow the evaluation of the processes modeled as to its relevance to a best estimate of productivity in eucalyptus forests. 3-PG model is the simplest of the models chosen for this exercise. Its main purpose is to estimate productivity of forests in timber production. The model uses the relationship of quantum efficiency in the transformation of light energy into biomass for vegetative growth calculations in steps in time of one month. Adverse weather conditions are treated with reduction factors applied in the top efficiency. The second model is the Biome-BGC that uses biology and geochemistry principles to estimate leaf-level photosynthesis based on limiting factors such as availability of light and nutrient constraints. The

  3. Modeling multicomponent ionic transport in groundwater with IPhreeqc coupling: Electrostatic interactions and geochemical reactions in homogeneous and heterogeneous domains

    DEFF Research Database (Denmark)

    Muniruzzaman, Muhammad; Rolle, Massimo

    2016-01-01

    The key role of small-scale processes like molecular diffusion and electrochemical migration has been increasingly recognized in multicomponent reactive transport in saturated porous media. In this study, we propose a two-dimensional multicomponent reactive transport model taking into account...... the electrostatic interactions during transport of charged ions in physically and chemically heterogeneous porous media. The modeling approach is based on the local charge balance and on the description of compound-specific and spatially variable diffusive/dispersive fluxes. The multicomponent ionic transport code...

  4. A consistent geochemical modelling approach for the leaching and reactive transport of major and trace elements in MSWI bottom ash

    NARCIS (Netherlands)

    Dijkstra, J.J.; Meeussen, J.C.L.; Sloot, van der H.A.; Comans, R.N.J.

    2008-01-01

    To improve the long-term environmental risk assessment of waste applications, a predictive "multi-surface" modelling approach has been developed to simultaneously predict the leaching and reactive transport of a broad range of major and trace elements (i.e., pH, Na, Al, Fe, Ca, SO4, Mg, Si, PO4, CO3

  5. A coupled geochemical-transport-geomechanical model to address caprock integrity during long-term CO2 storage

    NARCIS (Netherlands)

    Veer, E.F. van der; Waldmann, S.; Fokker, P.A.

    2015-01-01

    Underground storage of CO2 will lead to chemical fluid-rock interactions which may potentially alter the porosity and the flow patterns in faults. In this study, we present a coupled numerical model combining chemical fluid-rock interactions, aqueous diffusion, fluid flow, and mechanical processes,

  6. FORWARD AND INVERSE BIO-GEOCHEMICAL MODELING OF MICROBIALLY INDUCED PRECIPITATION IN 0.5M COLUMNAR EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Tammer Barkouki; Brian Martinez; Brina Mortensen; Tess Weathers; Jason DeJong; Nic Spycher; Tim Ginn; Yoshiko Fujita; Robert Smith

    2009-09-01

    Microbial ureolysis-induced calcite precipitation may offer an in situ remediation for heavy metal and radionuclide contamination, as well as an alternative to traditional soil strengthening techniques. A microbially mediated calcite precipitation model was built in TOUGHREACT v2 and calibrated to batch and columnar experimental data. Kinetic ureolysis and calcite precipitation-rate expressions were parameterized by coupling TOUCHREACT with UCODE.

  7. A consistent geochemical modelling approach for the leaching and reactive transport of major and trace elements in MSWI bottom ash

    NARCIS (Netherlands)

    Dijkstra, J.J.; Meeussen, J.C.L.; Sloot, van der H.A.; Comans, R.N.J.

    2008-01-01

    To improve the long-term environmental risk assessment of waste applications, a predictive "multi-surface" modelling approach has been developed to simultaneously predict the leaching and reactive transport of a broad range of major and trace elements (i.e., pH, Na, Al, Fe, Ca, SO4, Mg, Si, PO4, CO3

  8. Modelling the impact of soil Carbonic Anhydrase on the net ecosystem exchange of OCS at Harvard forest using the MuSICA model

    Science.gov (United States)

    Launois, Thomas; Ogée, Jérôme; Commane, Roisin; Wehr, Rchard; Meredith, Laura; Munger, Bill; Nelson, David; Saleska, Scott; Wofsy, Steve; Zahniser, Mark; Wingate, Lisa

    2016-04-01

    The exchange of CO2 between the terrestrial biosphere and the atmosphere is driven by photosynthetic uptake and respiratory loss, two fluxes currently estimated with considerable uncertainty at large scales. Model predictions indicate that these biosphere fluxes will be modified in the future as CO2 concentrations and temperatures increase; however, it still unclear to what extent. To address this challenge there is a need for better constraints on land surface model parameterisations. Additional atmospheric tracers of large-scale CO2 fluxes have been identified as potential candidates for this task. In particular carbonyl sulphide (OCS) has been proposed as a complementary tracer of gross photosynthesis over land, since OCS uptake by plants is dominated by carbonic anhydrase (CA) activity, an enzyme abundant in leaves that catalyses CO2 hydration during photosynthesis. However, although the mass budget at the ecosystem is dominated by the flux of OCS into leaves, some OCS is also exchanged between the atmosphere and the soil and this component of the budget requires constraining. In this study, we adapted the process-based isotope-enabled model MuSICA (Multi-layer Simulator of the Interactions between a vegetation Canopy and the Atmosphere) to include the transport, reaction, diffusion and production of OCS within a forested ecosystem. This model was combined with 3 years (2011-2013) of in situ measurements of OCS atmospheric concentration profiles and fluxes at the Harvard Forest (Massachussets, USA) to test hypotheses on the mechanisms responsible for CA-driven uptake by leaves and soils as well as possible OCS emissions during litter decomposition. Model simulations over the three years captured well the impact of diurnally and seasonally varying environmental conditions on the net ecosystem OCS flux. A sensitivity analysis on soil CA activity and soil OCS emission rates was also performed to quantify their impact on the vertical profiles of OCS inside the

  9. Leaching, geochemical modelling and field verification of a municipal solid waste and a predominantly non-degradable waste landfill.

    Science.gov (United States)

    van der Sloot, H A; Kosson, D S; van Zomeren, A

    2017-05-01

    In spite of the known heterogeneity, wastes destined for landfilling can be characterised for their leaching behaviour by the same protocols as soil, contaminated soil, sediments, sludge, compost, wood, waste and construction products. Characterisation leaching tests used in conjunction with chemical speciation modelling results in much more detailed insights into release controlling processes and factors than single step batch leaching tests like TCLP (USEPA) and EN12457 (EU Landfill Directive). Characterisation testing also can provide the potential for mechanistic impact assessments by making use of a chemical speciation fingerprint (CSF) derived from pH dependence leaching test results. This CSF then forms the basis for subsequent chemical equilibrium and reactive transport modelling to assess environmental impact in a landfill scenario under relevant exposure conditions, including conditions not readily evaluated through direct laboratory testing. This approach has been applied to municipal solid waste (MSW) and predominantly non-degradable waste (PNW) that is representative of a significant part of waste currently being landfilled. This work has shown that a multi-element modelling approach provides a useful description of the release from each of these matrices because relevant release controlling properties and parameters (mineral dissolution/precipitation, sorption on Fe and Al oxides, clay interaction, interaction with dissolved and particulate organic carbon and incorporation in solid solutions) are taken into consideration. Inclusion of dissolved and particulate organic matter in the model is important to properly describe release of the low concentration trace constituents observed in the leachate. The CSF allows the prediction of release under different redox and degradation conditions in the landfill by modifying the redox status and level of dissolved and particulate organic matter in the model runs. The CSF for MSW provides a useful starting point

  10. Modeling net primary productivity of terrestrial ecosystems in the semi-arid climate of the Mongolian Plateau using LSWI-based CASA ecosystem model

    Science.gov (United States)

    Bao, Gang; Bao, Yuhai; Qin, Zhihao; Xin, Xiaoping; Bao, Yulong; Bayarsaikan, Sainbuyin; Zhou, Yi; Chuntai, Bilegtmandakh

    2016-04-01

    Since the estimate of moisture stress coefficients (MSC) in the current Carnegie-Ames-Stanford-Approach (CASA) model still requires considerable inputs from ground meteorological data and many soil parameters, here we present a modified CASA model by introducing the land-surface water index (LSWI) and scaled precipitation to model the vegetation net primary productivity (NPP) in the arid and semiarid climate of the Mongolian Plateau. The field-observed NPP data and a previously proposed model (the Yu-CASA model) were used to evaluate the performance of our LSWI-based CASA model. The results show that the NPP predicted by both the LSWI-based CASA model and the Yu-CASA model showed good agreement with the observed NPP in the grassland ecosystems in the study area, with coefficients of determination of 0.717 and 0.714, respectively. The LSWI-based CASA model also performed comparably with the Yu-CASA model at both biome and per-pixel scales when keeping other inputs unchanged, with a difference of approximately 16 g C in the growing-season total NPP and an average value of 2.3 g C bias for each month. This indicates that, unlike an earlier method that estimated MSC based entirely on climatic variables or a soil moisture model, the method proposed here simplifies the model structure, reduces the need for ground measurements, and can provide results comparable with those from earlier models. The LSWI-based CASA model is potentially an alternative method for modelling NPP for a wide range of vegetation types in the Mongolian Plateau.

  11. Predictive modeling of CO{sub 2} sequestration in deep saline sandstone reservoirs: Impacts of geochemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Balashov, Victor N; Guthrie, George D; Hakala, J Alexandra; Lopano, Christina L. J.; Rimstidt, Donald; Brantley, Susan L

    2013-03-01

    One idea for mitigating the increase in fossil-fuel generated CO{sub 2} in the atmosphere is to inject CO{sub 2} into subsurface saline sandstone reservoirs. To decide whether to try such sequestration at a globally significant scale will require the ability to predict the fate of injected CO{sub 2}. Thus, models are needed to predict the rates and extents of subsurface rock-water-gas interactions. Several reactive transport models for CO{sub 2} sequestration created in the last decade predicted sequestration in sandstone reservoirs of ~17 to ~90 kg CO{sub 2} m{sup -3|. To build confidence in such models, a baseline problem including rock + water chemistry is proposed as the basis for future modeling so that both the models and the parameterizations can be compared systematically. In addition, a reactive diffusion model is used to investigate the fate of injected supercritical CO{sub 2} fluid in the proposed baseline reservoir + brine system. In the baseline problem, injected CO{sub 2} is redistributed from the supercritical (SC) free phase by dissolution into pore brine and by formation of carbonates in the sandstone. The numerical transport model incorporates a full kinetic description of mineral-water reactions under the assumption that transport is by diffusion only. Sensitivity tests were also run to understand which mineral kinetics reactions are important for CO{sub 2} trapping. The diffusion transport model shows that for the first ~20 years after CO{sub 2} diffusion initiates, CO{sub 2} is mostly consumed by dissolution into the brine to form CO{sub 2,aq} (solubility trapping). From 20-200 years, both solubility and mineral trapping are important as calcite precipitation is driven by dissolution of oligoclase. From 200 to 1000 years, mineral trapping is the most important sequestration mechanism, as smectite dissolves and calcite precipitates. Beyond 2000 years, most trapping is due to formation of aqueous HCO{sub 3}{sup -}. Ninety-seven percent of the

  12. De-coupling of net community production and new production in the euphotic zone of the equatorial Pacific: A model study

    Science.gov (United States)

    Wang, Xiujun; Murtugudde, Ragu; Busalacchi, Antonio J.; Le Borgne, Robert

    2005-11-01

    A physical-biogeochemical model is employed to estimate rates of nitrogen based primary production (PP*), net community production (NCP*), and new production (NP) in the equatorial Pacific. The model reproduces observed vertical differences between ammonium regeneration and uptake: uptake > regeneration above 40 m and uptake over-consumption in the upper ocean of the equatorial Pacific with implications for predicting sinks/sources of CO2.

  13. The importance of sea-ice area biases in 21st century multi-model projections of Antarctic net precipitation and temperature and their relative change

    Science.gov (United States)

    Bracegirdle, T.

    2015-12-01

    Climate models exhibit large biases in sea ice area (SIA) in their historical simulations. This study has explored the impacts of these biases on multi-model uncertainty in CMIP5 ensemble projections of 21st century change in Antarctic surface temperature, net precipitation and SIA. The analysis is based on time slice climatologies in the RCP8.5 future scenario (2070-2099) and historical (1970-1999) simulations across 37 different CMIP5 models. Projected changes in net precipitation, temperature and SIA are found to be strongly associated with simulated historical mean SIA (e.g. cross-model correlations of r = 0.77, 0.70 and -0.86, respectively). Furthermore, historical SIA bias is found to have a large impact on the simulated ratio between net precipitation response and temperature response. This ratio is smaller in models with smaller-than-observed historical SIA. These findings are particularly relevant to quantifying and reducing model uncertainty in projections of Antarctic surface mass balance and associated contributions to sea level change.

  14. 旅游网式供应系统的ANP战略决策模型%ANP Strategic Decision-Making Model in Tourism Net-Supply System

    Institute of Scientific and Technical Information of China (English)

    秦立公; 吴娇; 董津津; 刘钰霞

    2011-01-01

    提出旅游网式供应系统内涵,运用ANP网络分析法建立了旅游网式供应系统战略决策模型,其指标体系的目标是旅游供需平衡,准则层包括找准需求点和迅速反应,网络层共6个指标即旅游服务、旅游人员、旅游物流、旅游E化、旅游金融、旅游规范.采用Super Decisions软件对2005、2008、2011年的数据组进行处理,快速实现了ANP模型的复杂计算,不同时期旅游网式供应的发展重点不同,从旅游网式供应组织关系、运作方式及服务流程阐述了旅游网式供应战略的实现.%Tourism net-supply system is defined and ANP strategic decision-making model based on ANP ( analytic network process) method is established. ANP network index system of the model consists of one target, two criterions in criteria cluster and six indexes in net cluster. The target is tourism supply-demand balance. One of the two criterions is finding out demand-points, the other is quick-response. The six indexes in net cluster are tourism service, tourism-human resource, tourism-logistics, e-tourism, tourism-finance, travel specialization. The data in 2005, 2008 and 2011 is done faster with Super Decisions (2003) software in the calculation of ANP. Finally, tourism net-supply strategy implementation is described with tourism net-supply relationship of organizations, operation model and service procedures.

  15. Perti Net-Based Workflow Access Control Model%基于Perti网的工作流访问控制模型研究

    Institute of Scientific and Technical Information of China (English)

    陈卓; 骆婷; 石磊; 洪帆

    2004-01-01

    Access control is an important protection mechanism for information systems.This paper shows how to make access control in workflow system.We give a workflow access control model (WACM) based on several current access control models.The model supports roles assignment and dynamic authorization.The paper defines the workflow using Petri net.It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM).Finally, an example of an e-commerce workflow access control model is discussed in detail.

  16. Contribution to the modelling and analysis of logistics system performance by Petri nets and simulation models: Application in a supply chain

    Science.gov (United States)

    Azougagh, Yassine; Benhida, Khalid; Elfezazi, Said

    2016-02-01

    In this paper, the focus is on studying the performance of complex systems in a supply chain context by developing a structured modelling approach based on the methodology ASDI (Analysis, Specification, Design and Implementation) by combining the modelling by Petri nets and simulation using ARENA. The linear approach typically followed in conducting of this kind of problems has to cope with a difficulty of modelling due to the complexity and the number of parameters of concern. Therefore, the approach used in this work is able to structure modelling a way to cover all aspects of the performance study. The modelling structured approach is first introduced before being applied to the case of an industrial system in the field of phosphate. Results of the performance indicators obtained from the models developed, permitted to test the behaviour and fluctuations of this system and to develop improved models of the current situation. In addition, in this paper, it was shown how Arena software can be adopted to simulate complex systems effectively. The method in this research can be applied to investigate various improvements scenarios and their consequences before implementing them in reality.

  17. Changes of net primary productivity in China during recent 11 years detected using an ecological model driven by MODIS data

    Institute of Scientific and Technical Information of China (English)

    Yibo LIU; Weimin JU; Honglin HE; Shaoqiang WANG; Rui SUN; Yuandong ZHANG

    2013-01-01

    Net primary productivity (NPP) is an important component of the terrestrial carbon cycle.Accurately mapping the spatial-temporal variations of NPP in China is crucial for global carbon cycling study.In this study the process-based Boreal Ecosystem Productivity Simulator (BEPS) was employed to study the changes of NPP in China's ecosystems for the period from 2000 to 2010.The BEPS model was first validated using gross primary productivity (GPP) measured at typical flux sites and forest NPP measured at different regions.Then it was driven with leaf area index (LAI) inversed from the Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance and land cover products and meteorological data interpolated from observations at753 national basic meteorological stations to simulate NPP at daily time steps and a spatial resolution of 500 m from January 1,2000 to December 31,2010.Validations show that BEPS is able to capture the seasonal variations of tower-based GPP and the spatial variability of forest NPP in different regions of China.Estimated national total of annual NPP varied from 2.63 to 2.84Pg C·yr-1,averaging 2.74Pg C.yr-1 during the study period.Simulated terrestrial NPP shows spatial patterns decreasing from the east to the west and from the south to the north,in association with land cover types and climate.South-west China makes the largest contribution to the national total of NPP while NPP in the North-west account for only 3.97%of the national total.During the recent 11 years,the temporal changes of NPP were heterogamous.NPP increased in 63.8% of China's landmass,mainly in areas north of the Yangtze River and decreased in most areas of southern China,owing to the low temperature freezing in early 2008 and the severe drought in late 2009.

  18. Changes of net primary productivity in China during recent 11 years detected using an ecological model driven by MODIS data

    Science.gov (United States)

    Liu, Yibo; Ju, Weimin; He, Honglin; Wang, Shaoqiang; Sun, Rui; Zhang, Yuandong

    2013-03-01

    Net primary productivity (NPP) is an important component of the terrestrial carbon cycle. Accurately mapping the spatial-temporal variations of NPP in China is crucial for global carbon cycling study. In this study the process-based Boreal Ecosystem Productivity Simulator (BEPS) was employed to study the changes of NPP in China's ecosystems for the period from 2000 to 2010. The BEPS model was first validated using gross primary productivity (GPP) measured at typical flux sites and forest NPP measured at different regions. Then it was driven with leaf area index (LAI) inversed from the Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance and land cover products and meteorological data interpolated from observations at 753 national basic meteorological stations to simulate NPP at daily time steps and a spatial resolution of 500 m from January 1, 2000 to December 31, 2010. Validations show that BEPS is able to capture the seasonal variations of tower-based GPP and the spatial variability of forest NPP in different regions of China. Estimated national total of annual NPP varied from 2.63 to 2.84Pg C·yr-1, averaging 2.74 Pg C·yr-1 during the study period. Simulated terrestrial NPP shows spatial patterns decreasing from the east to the west and from the south to the north, in association with land cover types and climate. South-west China makes the largest contribution to the national total of NPP while NPP in the North-west account for only 3.97% of the national total. During the recent 11 years, the temporal changes of NPP were heterogamous. NPP increased in 63.8% of China's landmass, mainly in areas north of the Yangtze River and decreased in most areas of southern China, owing to the low temperature freezing in early 2008 and the severe drought in late 2009.

  19. Integrated geochemical modelling of magmatic degassing and hydrothermal interaction: a case study from Kawah Ijen volcano, Indonesia

    Science.gov (United States)

    Vigouroux-Caillibot, N.; Williams-Jones, G.; Berlo, K.; van Hinsberg, V.; Palmer, S.; Scher, S.; Williams-Jones, W.; Wallace, P. J.

    2010-12-01

    Monitoring active volcanoes requires an understanding of magmatic degassing in relation to magma depth, temperature, composition, style of degassing (open vs closed) and interactions with hydrothermal systems. This study combines results of subsurface degassing (interpreted from melt inclusions) with measurements of fumarole gases and acid spring waters from Kawah Ijen volcano, Indonesia. Kawah Ijen is a stratovolcano with a growing rhyolite dome on the shore of a hyperacidic crater lake. The dome is emitting sulfur-rich gases from high temperature fumaroles (350-450°C). Matrix glass and melt inclusion compositions (including H2O, CO2, S, Cl and F) were measured for basaltic, dacitic and rhyolitic magmas. The behavior of the volatile species (Dvap-melt) during ascent, degassing and crystallization were modeled for an open system (including vapor fluxing) assuming Rayleigh fractionation, and for closed system processes assuming batch degassing and crystallization. The variable H2O-CO2 contents of the melt inclusions suggest that open system vapor fluxing (XH2Ovapor = 0.25-0.95 for basalt; 0.9-0.95 for dacite) is the dominant degassing style. The modeled S Dvap-melt values for basalt remain low (2-10) as the melt ascends (P= 400 to 100 MPa), then increase sharply to 200 at pressures independent of pressure. Evolution from dacite to rhyolite is characterized by a constant Dvap-melt value of 35. Chlorine behavior is strongly affected by crystallization of Cl-rich apatite in the basaltic magma. In dacite and rhyolite, Cl is mostly dissolved in the melt. The Dvap-melt values range from 7-9 as basalt evolves to dacite and reach 5 for dacite to rhyolite (low pressure degassing). Fluorine contents are highly variable due to crystallization of F-apatite, especially in the more evolved rocks. This precludes meaningful modeling of F-release to the vapor. The best-fit modeled gas compositions (mass ratio) are: CO2/H2O = 0.13-0.27, CO2/S(total) = 2.9-5.7, H2O/S(total) = 21

  20. Data-driven approach to identify field-scale biogeochemical transitions using geochemical and geophysical