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Sample records for combustion code ncc

  1. Assessment of Turbulence-Chemistry Interaction Models in the National Combustion Code (NCC) - Part I

    Science.gov (United States)

    Wey, Thomas Changju; Liu, Nan-suey

    2011-01-01

    This paper describes the implementations of the linear-eddy model (LEM) and an Eulerian FDF/PDF model in the National Combustion Code (NCC) for the simulation of turbulent combustion. The impacts of these two models, along with the so called laminar chemistry model, are then illustrated via the preliminary results from two combustion systems: a nine-element gas fueled combustor and a single-element liquid fueled combustor.

  2. Assessment of Microphysical Models in the National Combustion Code (NCC) for Aircraft Particulate Emissions: Particle Loss in Sampling Lines

    Science.gov (United States)

    Wey, Thomas; Liu, Nan-Suey

    2008-01-01

    This paper at first describes the fluid network approach recently implemented into the National Combustion Code (NCC) for the simulation of transport of aerosols (volatile particles and soot) in the particulate sampling systems. This network-based approach complements the other two approaches already in the NCC, namely, the lower-order temporal approach and the CFD-based approach. The accuracy and the computational costs of these three approaches are then investigated in terms of their application to the prediction of particle losses through sample transmission and distribution lines. Their predictive capabilities are assessed by comparing the computed results with the experimental data. The present work will help establish standard methodologies for measuring the size and concentration of particles in high-temperature, high-velocity jet engine exhaust. Furthermore, the present work also represents the first step of a long term effort of validating physics-based tools for the prediction of aircraft particulate emissions.

  3. Comparing Spray Characteristics from Reynolds Averaged Navier-Stokes (RANS) National Combustion Code (NCC) Calculations Against Experimental Data for a Turbulent Reacting Flow

    Science.gov (United States)

    Iannetti, Anthony C.; Moder, Jeffery P.

    2010-01-01

    Developing physics-based tools to aid in reducing harmful combustion emissions, like Nitrogen Oxides (NOx), Carbon Monoxide (CO), Unburnt Hydrocarbons (UHC s), and Sulfur Dioxides (SOx), is an important goal of aeronautics research at NASA. As part of that effort, NASA Glenn Research Center is performing a detailed assessment and validation of an in-house combustion CFD code known as the National Combustion Code (NCC) for turbulent reacting flows. To assess the current capabilities of NCC for simulating turbulent reacting flows with liquid jet fuel injection, a set of Single Swirler Lean Direct Injection (LDI) experiments performed at the University of Cincinnati was chosen as an initial validation data set. This Jet-A/air combustion experiment operates at a lean equivalence ratio of 0.75 at atmospheric pressure and has a 4 percent static pressure drop across the swirler. Detailed comparisons of NCC predictions for gas temperature and gaseous emissions (CO and NOx) against this experiment are considered in a previous work. The current paper is focused on detailed comparisons of the spray characteristics (radial profiles of drop size distribution and at several radial rakes) from NCC simulations against the experimental data. Comparisons against experimental data show that the use of the correlation for primary spray break-up implemented by Raju in the NCC produces most realistic results, but this result needs to be improved. Given the single or ten step chemical kinetics models, use of a spray size correlation gives similar, acceptable results

  4. Spray and High-Pressure Flow Computations in the National Combustion Code (NCC) Improved

    Science.gov (United States)

    Raju, Manthena S.

    2002-01-01

    Sprays occur in a wide variety of industrial and power applications and in materials processing. A liquid spray is a two-phase flow with a gas as the continuous phase and a liquid as the dispersed phase in the form of droplets or ligaments. The interactions between the two phases--which are coupled through exchanges of mass, momentum, and energy--can occur in different ways at disparate time and length scales involving various thermal, mass, and fluid dynamic factors. An understanding of the flow, combustion, and thermal properties of a rapidly vaporizing spray requires careful modeling of the ratecontrolling processes associated with turbulent transport, mixing, chemical kinetics, evaporation, and spreading rates of the spray, among many other factors. With the aim of developing an efficient solution procedure for use in multidimensional combustor modeling, researchers at the NASA Glenn Research Center have advanced the state-of-the-art in spray computations in several important ways.

  5. NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

    Science.gov (United States)

    Liu, Nan-Suey; Quealy, Angela

    1999-01-01

    A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

  6. NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

    Science.gov (United States)

    Liu, Nan-Suey; Quealy, Angela

    1999-01-01

    A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

  7. Assessment of the Partially Resolved Numerical Simulation (PRNS) Approach in the National Combustion Code (NCC) for Turbulent Nonreacting and Reacting Flows

    Science.gov (United States)

    Shih, Tsan-Hsing; Liu, Nan-Suey

    2008-01-01

    This paper describes an approach which aims at bridging the gap between the traditional Reynolds-averaged Navier-Stokes (RANS) approach and the traditional large eddy simulation (LES) approach. It has the characteristics of the very large eddy simulation (VLES) and we call this approach the partially-resolved numerical simulation (PRNS). Systematic simulations using the National Combustion Code (NCC) have been carried out for fully developed turbulent pipe flows at different Reynolds numbers to evaluate the PRNS approach. Also presented are the sample results of two demonstration cases: nonreacting flow in a single injector flame tube and reacting flow in a Lean Direct Injection (LDI) hydrogen combustor.

  8. NCC: A Physics-Based Design and Analysis Tool for Combustion Systems

    Science.gov (United States)

    Liu, Nan-Suey; Quealy, Angela

    2000-01-01

    The National Combustion Code (NCC) is an integrated system of computer codes for physics-based design and analysis of combustion systems. It uses unstructured meshes and runs on parallel computing platforms. The NCC is composed of a set of distinct yet closely related modules. They are: (1) a gaseous flow module solving 3-D Navier-Stokes equations; (2) a turbulence module containing the non-linear k-epsilon models; (3) a chemistry module using either the conventional reduced kinetics approach of solving species equations or the Intrinsic Low Dimensional Manifold (ILDM) kinetics approach of table looking up in conjunction with solving the equations of the progressive variables; (4) a turbulence-chemistry interaction module including the option of solving the joint probability density function (PDF) for species and enthalpy; and (5) a spray module for solving the liquid phase equations. In early 1995, an industry-government team was formed to develop the NCC. In July 1998, the baseline beta version was completed and presented in two NCC sessions at the 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 1998. An overview of this baseline beta version was presented at the NASA HPCCP/CAS Workshop 98, August 1998. Since then, the effort has been focused on the streamlining, validation, and enhancement of the th baseline beta version. The progress is presented in two NCC sessions at the AIAA 38 Aerospace Sciences Meeting & Exhibit, January 2000. At this NASA HPCCP/CAS Workshop 2000, an overview of the NCC papers presented at the AIAA 38 th Aerospace Sciences Meeting & Exhibit is presented, with emphasis on the reduction of analysis time of simulating the (gaseous) reacting flows in full combustors. In addition, results of NCC simulation of a modern turbofan combustor will also be reported.

  9. NCC: A Physics-Based Design and Analysis Tool for Combustion Systems

    Science.gov (United States)

    Liu, Nan-Suey; Quealy, Angela

    2000-01-01

    The National Combustion Code (NCC) is an integrated system of computer codes for physics-based design and analysis of combustion systems. It uses unstructured meshes and runs on parallel computing platforms. The NCC is composed of a set of distinct yet closely related modules. They are: (1) a gaseous flow module solving 3-D Navier-Stokes equations; (2) a turbulence module containing the non-linear k-epsilon models; (3) a chemistry module using either the conventional reduced kinetics approach of solving species equations or the Intrinsic Low Dimensional Manifold (ILDM) kinetics approach of table looking up in conjunction with solving the equations of the progressive variables; (4) a turbulence-chemistry interaction module including the option of solving the joint probability density function (PDF) for species and enthalpy; and (5) a spray module for solving the liquid phase equations. In early 1995, an industry-government team was formed to develop the NCC. In July 1998, the baseline beta version was completed and presented in two NCC sessions at the 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 1998. An overview of this baseline beta version was presented at the NASA HPCCP/CAS Workshop 98, August 1998. Since then, the effort has been focused on the streamlining, validation, and enhancement of the th baseline beta version. The progress is presented in two NCC sessions at the AIAA 38 Aerospace Sciences Meeting & Exhibit, January 2000. At this NASA HPCCP/CAS Workshop 2000, an overview of the NCC papers presented at the AIAA 38 th Aerospace Sciences Meeting & Exhibit is presented, with emphasis on the reduction of analysis time of simulating the (gaseous) reacting flows in full combustors. In addition, results of NCC simulation of a modern turbofan combustor will also be reported.

  10. Validation of the NCC Code for Staged Transverse Injection and Computations for a RBCC Combustor

    Science.gov (United States)

    Ajmani, Kumud; Liu, Nan-Suey

    2005-01-01

    The NCC code was validated for a case involving staged transverse injection into Mach 2 flow behind a rearward facing step. Comparisons with experimental data and with solutions from the FPVortex code was then used to perform computations to study fuel-air mixing for the combustor of a candidate rocket based combined cycle engine geometry. Comparisons with a one-dimensional analysis and a three-dimensional code (VULCAN) were performed to assess the qualitative and quantitative performance of the NCC solver.

  11. Subgrid Combustion Modeling for the Next Generation National Combustion Code

    Science.gov (United States)

    Menon, Suresh; Sankaran, Vaidyanathan; Stone, Christopher

    2003-01-01

    In the first year of this research, a subgrid turbulent mixing and combustion methodology developed earlier at Georgia Tech has been provided to researchers at NASA/GRC for incorporation into the next generation National Combustion Code (called NCCLES hereafter). A key feature of this approach is that scalar mixing and combustion processes are simulated within the LES grid using a stochastic 1D model. The subgrid simulation approach recovers locally molecular diffusion and reaction kinetics exactly without requiring closure and thus, provides an attractive feature to simulate complex, highly turbulent reacting flows of interest. Data acquisition algorithms and statistical analysis strategies and routines to analyze NCCLES results have also been provided to NASA/GRC. The overall goal of this research is to systematically develop and implement LES capability into the current NCC. For this purpose, issues regarding initialization and running LES are also addressed in the collaborative effort. In parallel to this technology transfer effort (that is continuously on going), research has also been underway at Georgia Tech to enhance the LES capability to tackle more complex flows. In particular, subgrid scalar mixing and combustion method has been evaluated in three distinctly different flow field in order to demonstrate its generality: (a) Flame-Turbulence Interactions using premixed combustion, (b) Spatially evolving supersonic mixing layers, and (c) Temporal single and two-phase mixing layers. The configurations chosen are such that they can be implemented in NCCLES and used to evaluate the ability of the new code. Future development and validation will be in spray combustion in gas turbine engine and supersonic scalar mixing.

  12. Overview of the NCC

    Science.gov (United States)

    Liu, Nan-Suey

    2001-01-01

    A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between then NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Glenn Research Center (LeRC), and Pratt & Whitney (P&W). The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration. The development of the NCC beta version was essentially completed in June 1998. Technical details of the NCC elements are given in the Reference List. Elements such as the baseline flow solver, turbulence module, and the chemistry module, have been extensively validated; and their parallel performance on large-scale parallel systems has been evaluated and optimized. However the scalar PDF module and the Spray module, as well as their coupling with the baseline flow solver, were developed in a small-scale distributed

  13. Combustion chamber analysis code

    Science.gov (United States)

    Przekwas, A. J.; Lai, Y. G.; Krishnan, A.; Avva, R. K.; Giridharan, M. G.

    1993-05-01

    A three-dimensional, time dependent, Favre averaged, finite volume Navier-Stokes code has been developed to model compressible and incompressible flows (with and without chemical reactions) in liquid rocket engines. The code has a non-staggered formulation with generalized body-fitted-coordinates (BFC) capability. Higher order differencing methodologies such as MUSCL and Osher-Chakravarthy schemes are available. Turbulent flows can be modeled using any of the five turbulent models present in the code. A two-phase, two-liquid, Lagrangian spray model has been incorporated into the code. Chemical equilibrium and finite rate reaction models are available to model chemically reacting flows. The discrete ordinate method is used to model effects of thermal radiation. The code has been validated extensively against benchmark experimental data and has been applied to model flows in several propulsion system components of the SSME and the STME.

  14. A Radiation Solver for the National Combustion Code

    Science.gov (United States)

    Sockol, Peter M.

    2015-01-01

    A methodology is given that converts an existing finite volume radiative transfer method that requires input of local absorption coefficients to one that can treat a mixture of combustion gases and compute the coefficients on the fly from the local mixture properties. The Full-spectrum k-distribution method is used to transform the radiative transfer equation (RTE) to an alternate wave number variable, g . The coefficients in the transformed equation are calculated at discrete temperatures and participating species mole fractions that span the values of the problem for each value of g. These results are stored in a table and interpolation is used to find the coefficients at every cell in the field. Finally, the transformed RTE is solved for each g and Gaussian quadrature is used to find the radiant heat flux throughout the field. The present implementation is in an existing cartesian/cylindrical grid radiative transfer code and the local mixture properties are given by a solution of the National Combustion Code (NCC) on the same grid. Based on this work the intention is to apply this method to an existing unstructured grid radiation code which can then be coupled directly to NCC.

  15. Beta Testing of CFD Code for the Analysis of Combustion Systems

    Science.gov (United States)

    Yee, Emma; Wey, Thomas

    2015-01-01

    A preliminary version of OpenNCC was tested to assess its accuracy in generating steady-state temperature fields for combustion systems at atmospheric conditions using three-dimensional tetrahedral meshes. Meshes were generated from a CAD model of a single-element lean-direct injection combustor, and the latest version of OpenNCC was used to calculate combustor temperature fields. OpenNCC was shown to be capable of generating sustainable reacting flames using a tetrahedral mesh, and the subsequent results were compared to experimental results. While nonreacting flow results closely matched experimental results, a significant discrepancy was present between the code's reacting flow results and experimental results. When wide air circulation regions with high velocities were present in the model, this appeared to create inaccurately high temperature fields. Conversely, low recirculation velocities caused low temperature profiles. These observations will aid in future modification of OpenNCC reacting flow input parameters to improve the accuracy of calculated temperature fields.

  16. Towards Accurate Prediction of Turbulent, Three-Dimensional, Recirculating Flows with the NCC

    Science.gov (United States)

    Iannetti, A.; Tacina, R.; Jeng, S.-M.; Cai, J.

    2001-01-01

    The National Combustion Code (NCC) was used to calculate the steady state, nonreacting flow field of a prototype Lean Direct Injection (LDI) swirler. This configuration used nine groups of eight holes drilled at a thirty-five degree angle to induce swirl. These nine groups created swirl in the same direction, or a corotating pattern. The static pressure drop across the holes was fixed at approximately four percent. Computations were performed on one quarter of the geometry, because the geometry is considered rotationally periodic every ninety degrees. The final computational grid used was approximately 2.26 million tetrahedral cells, and a cubic nonlinear k - epsilon model was used to model turbulence. The NCC results were then compared to time averaged Laser Doppler Velocimetry (LDV) data. The LDV measurements were performed on the full geometry, but four ninths of the geometry was measured. One-, two-, and three-dimensional representations of both flow fields are presented. The NCC computations compare both qualitatively and quantitatively well to the LDV data, but differences exist downstream. The comparison is encouraging, and shows that NCC can be used for future injector design studies. To improve the flow prediction accuracy of turbulent, three-dimensional, recirculating flow fields with the NCC, recommendations are given.

  17. NCC kujundas kontori koduks

    Index Scriptorium Estoniae

    2005-01-01

    25. XI 2005 pidas NCC Ehituse AS Tallinnas Kalamaja t. 4 Kodupoe avapidu. Kodupoes müüakse NCC arendatud ja ehitatud kortereid. Elamispindade müügibüroo kujundas koduna Kadri Pärtelpoeg. 3 värv. ill

  18. NCC kujundas kontori koduks

    Index Scriptorium Estoniae

    2005-01-01

    25. XI 2005 pidas NCC Ehituse AS Tallinnas Kalamaja t. 4 Kodupoe avapidu. Kodupoes müüakse NCC arendatud ja ehitatud kortereid. Elamispindade müügibüroo kujundas koduna Kadri Pärtelpoeg. 3 värv. ill

  19. Integration of CFD codes and advanced combustion models for quantitative burnout determination

    Energy Technology Data Exchange (ETDEWEB)

    Javier Pallares; Inmaculada Arauzo; Alan Williams [University of Zaragoza, Zaragoza (Spain). Centre of Research for Energy Resources and Consumption (CIRCE)

    2007-10-15

    CFD codes and advanced kinetics combustion models are extensively used to predict coal burnout in large utility boilers. Modelling approaches based on CFD codes can accurately solve the fluid dynamics equations involved in the problem but this is usually achieved by including simple combustion models. On the other hand, advanced kinetics combustion models can give a detailed description of the coal combustion behaviour by using a simplified description of the flow field, this usually being obtained from a zone-method approach. Both approximations describe correctly general trends on coal burnout, but fail to predict quantitative values. In this paper a new methodology which takes advantage of both approximations is described. In the first instance CFD solutions were obtained of the combustion conditions in the furnace in the Lamarmora power plant (ASM Brescia, Italy) for a number of different conditions and for three coals. Then, these furnace conditions were used as inputs for a more detailed chemical combustion model to predict coal burnout. In this, devolatilization was modelled using a commercial macromolecular network pyrolysis model (FG-DVC). For char oxidation an intrinsic reactivity approach including thermal annealing, ash inhibition and maceral effects, was used. Results from the simulations were compared against plant experimental values, showing a reasonable agreement in trends and quantitative values. 28 refs., 4 figs., 4 tabs.

  20. Current Status of Superheat Spray Modeling With NCC

    Science.gov (United States)

    Raju, M. S.; Bulzan, Dan L.

    2012-01-01

    An understanding of liquid fuel behavior at superheat conditions is identified to be a topic of importance in the design of modern supersonic engines. As a part of the NASA's supersonics project office initiative on high altitude emissions, we have undertaken an effort to assess the accuracy of various existing CFD models used in the modeling of superheated sprays. As a part of this investigation, we have completed the implementation of a modeling approach into the national combustion code (NCC), and then applied it to investigate the following three cases: (1) the validation of a flashing jet generated by the sudden release of pressurized R134A from a cylindrical nozzle, (2) the differences between two superheat vaporization models were studied based on both hot and cold flow calculations of a Parker-Hannifin pressure swirl atomizer, (3) the spray characteristics generated by a single-element LDI (Lean Direct Injector) experiment were studied to investigate the differences between superheat and non-superheat conditions. Further details can be found in the paper.

  1. Numerical Simulations of Two-Phase Reacting Flow in a Single-Element Lean Direct Injection (LDI) Combustor Using NCC

    Science.gov (United States)

    Liu, Nan-Suey; Shih, Tsan-Hsing; Wey, C. Thomas

    2011-01-01

    A series of numerical simulations of Jet-A spray reacting flow in a single-element lean direct injection (LDI) combustor have been conducted by using the National Combustion Code (NCC). The simulations have been carried out using the time filtered Navier-Stokes (TFNS) approach ranging from the steady Reynolds-averaged Navier-Stokes (RANS), unsteady RANS (URANS), to the dynamic flow structure simulation (DFS). The sub-grid model employed for turbulent mixing and combustion includes the well-mixed model, the linear eddy mixing (LEM) model, and the filtered mass density function (FDF/PDF) model. The starting condition of the injected liquid spray is specified via empirical droplet size correlation, and a five-species single-step global reduced mechanism is employed for fuel chemistry. All the calculations use the same grid whose resolution is of the RANS type. Comparisons of results from various models are presented.

  2. NCC and Computers in Education.

    Science.gov (United States)

    Brown, Ron L.

    1982-01-01

    This introduction to the work of the National Computing Centre (NCC), looks at industry/education links, the development of case studies, the use of computers in training, work in the Department of Industry - Micros in Schools Scheme, and at the Department of Education and Science-Micro-Electronics in Education Programme. (MP)

  3. GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 3: Assessment Manual

    Energy Technology Data Exchange (ETDEWEB)

    Müller, C.; Hughes, E. D.; Niederauer, G. F.; Wilkening, H.; Travis, J. R.; Spore, J. W.; Royl, P.; Baumann, W.

    1998-10-01

    Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best- estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containment and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included. Volume

  4. National Combustion Code Validated Against Lean Direct Injection Flow Field Data

    Science.gov (United States)

    Iannetti, Anthony C.

    2003-01-01

    Most combustion processes have, in some way or another, a recirculating flow field. This recirculation stabilizes the reaction zone, or flame, but an unnecessarily large recirculation zone can result in high nitrogen oxide (NOx) values for combustion systems. The size of this recirculation zone is crucial to the performance of state-of-the-art, low-emissions hardware. If this is a large-scale combustion process, the flow field will probably be turbulent and, therefore, three-dimensional. This research dealt primarily with flow fields resulting from lean direct injection (LDI) concepts, as described in Research & Technology 2001. LDI is a concept that depends heavily on the design of the swirler. The LDI concept has the potential to reduce NOx values from 50 to 70 percent of current values, with good flame stability characteristics. It is cost effective and (hopefully) beneficial to do most of the design work for an LDI swirler using computer-aided design (CAD) and computer-aided engineering (CAE) tools. Computational fluid dynamics (CFD) codes are CAE tools that can calculate three-dimensional flows in complex geometries. However, CFD codes are only beginning to correctly calculate the flow fields for complex devices, and the related combustion models usually remove a large portion of the flow physics.

  5. A high-order public domain code for direct numerical simulations of turbulent combustion

    CERN Document Server

    Babkovskaia, N; Brandenburg, A

    2010-01-01

    A high-order scheme for direct numerical simulations of turbulent combustion is discussed. Its implementation in the massively parallel and publicly available Pencil Code is validated with the focus on hydrogen combustion. Ignition delay times (0D) and laminar flame velocities (1D) are calculated and compared with results from the commercially available Chemkin code. The scheme is verified to be fifth order in space. Upon doubling the resolution, a 32-fold increase in the accuracy of the flame front is demonstrated. Finally, also turbulent and spherical flame front velocities are calculated and the implementation of the non-reflecting so-called Navier-Stokes Characteristic Boundary Condition is validated in all three directions.

  6. Non-linear simulations of combustion instabilities with a quasi-1D Navier-Stokes code

    CERN Document Server

    Haugen, Nils Erland L; Sannan, Sigurd

    2010-01-01

    As lean premixed combustion systems are more susceptible to combustion instabilities than non-premixed systems, there is an increasing demand for improved numerical design tools that can predict the occurrence of combustion instabilities with high accuracy. The inherent non-linearities in combustion instabilities can be of crucial importance, and we here propose an approach in which the one-dimensional Navier-Stokes and scalar transport equations are solved for geometries of variable cross-section. The focus is on attached flames, and for this purpose a new phenomenological model for the unsteady heat release from a flame front is introduced. In the attached flame method (AFM) the heat release occurs over the full length of the flame. The non-linear code with the use of the AFM approach is validated against results from an experimental study of thermoacoustic instabilities in oxy-fuel flames by Ditaranto and Hals [Combustion and Flame, 146, 493-512 (2006)]. The numerical simulations are in accordance with the...

  7. Combustion

    CERN Document Server

    Glassman, Irvin

    1987-01-01

    Combustion, Second Edition focuses on the underlying principles of combustion and covers topics ranging from chemical thermodynamics and flame temperatures to chemical kinetics, detonation, ignition, and oxidation characteristics of fuels. Diffusion flames, flame phenomena in premixed combustible gases, and combustion of nonvolatile fuels are also discussed. This book consists of nine chapters and begins by introducing the reader to heats of reaction and formation, free energy and the equilibrium constants, and flame temperature calculations. The next chapter explores the rates of reactio

  8. An ecotoxicological characterization of nanocrystalline cellulose (NCC).

    Science.gov (United States)

    Kovacs, Tibor; Naish, Valerie; O'Connor, Brian; Blaise, Christian; Gagné, Francois; Hall, Lauren; Trudeau, Vance; Martel, Pierre

    2010-09-01

    The pulp and paper industry in Canada is developing technology for the production and use of nanocrystalline cellulose (NCC). A key component of the developmental work is an assessment of potential environmental risks. Towards this goal, NCC samples as well as carboxyl methyl cellulose (CMC), a surrogate of the parent cellulosic material, were subjected to an ecotoxicological evaluation. This involved toxicity tests with rainbow trout hepatocytes and nine aquatic species. The hepatocytes were most sensitive (EC20s between 10 and 200 mg/l) to NCC, although neither NCC nor CMC caused genotoxicity. In tests with the nine species, NCC affected the reproduction of the fathead minnow at (IC25) 0.29 g/l, but no other effects on endpoints such as survival and growth occurred in the other species at concentrations below 1 g/l, which was comparable to CMC. Based on this ecotoxicological characterization, NCC was found to have low toxicity potential and environmental risk.

  9. Sodium combustion computer code ASSCOPS version 2.0 user`s manual

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Hiroyasu; Futagami, Satoshi; Ohno, Shuji; Seino, Hiroshi; Miyake, Osamu [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-12-01

    ASSCOPS (Analysis of Simultaneous Sodium Combustion in Pool and Spray) has been developed for analyses of thermal consequences of sodium leak and fire accidents in LMFBRs. This report presents a description of the computational models, input, and output as the user`s manual of ASSCOPS version 2.0. ASSCOPS is an integrated code based on the sodium pool fire code SOFIRE II developed by the Atomics International Division of Rockwell International, and the sodium spray fire code SPRAY developed by the Hanford Engineering Development Laboratory in the U.S. The experimental studies conducted at PNC have been reflected in the ASSCOPS improvement. The users of ASSCOPS need to specify the sodium leak conditions (leak flow rate and temperature, etc.), the cell geometries (volume and structure surface area and thickness, etc.), and the atmospheric initial conditions, such as gas temperature, pressure, and gas composition. ASSCOPS calculates the time histories of atmospheric pressure and temperature changes along with those of the structural temperatures. (author)

  10. The NCC project: A quality management perspective

    Science.gov (United States)

    Lee, Raymond H.

    1993-01-01

    The Network Control Center (NCC) Project introduced the concept of total quality management (TQM) in mid-1990. The CSC project team established a program which focused on continuous process improvement in software development methodology and consistent deliveries of high quality software products for the NCC. The vision of the TQM program was to produce error free software. Specific goals were established to allow continuing assessment of the progress toward meeting the overall quality objectives. The total quality environment, now a part of the NCC Project culture, has become the foundation for continuous process improvement and has resulted in the consistent delivery of quality software products over the last three years.

  11. Phosphorylation regulates NCC stability and transporter activity in vivo.

    Science.gov (United States)

    Yang, Sung-Sen; Fang, Yu-Wei; Tseng, Min-Hua; Chu, Pei-Yi; Yu, I-Shing; Wu, Han-Chung; Lin, Shu-Wha; Chau, Tom; Uchida, Shinichi; Sasaki, Sei; Lin, Yuh-Feng; Sytwu, Huey-Kang; Lin, Shih-Hua

    2013-10-01

    A T60M mutation in the thiazide-sensitive sodium chloride cotransporter (NCC) is common in patients with Gitelman's syndrome (GS). This mutation prevents Ste20-related proline and alanine-rich kinase (SPAK)/oxidative stress responsive kinase-1 (OSR1)-mediated phosphorylation of NCC and alters NCC transporter activity in vitro. Here, we examined the physiologic effects of NCC phosphorylation in vivo using a novel Ncc T58M (human T60M) knock-in mouse model. Ncc(T58M/T58M) mice exhibited typical features of GS with a blunted response to thiazide diuretics. Despite expressing normal levels of Ncc mRNA, these mice had lower levels of total Ncc and p-Ncc protein that did not change with a low-salt diet that increased p-Spak. In contrast to wild-type Ncc, which localized to the apical membrane of distal convoluted tubule cells, T58M Ncc localized primarily to the cytosolic region and caused an increase in late distal convoluted tubule volume. In MDCK cells, exogenous expression of phosphorylation-defective NCC mutants reduced total protein expression levels and membrane stability. Furthermore, our analysis found diminished total urine NCC excretion in a cohort of GS patients with homozygous NCC T60M mutations. When Wnk4(D561A/+) mice, a model of pseudohypoaldosteronism type II expressing an activated Spak/Osr1-Ncc, were crossed with Ncc(T58M/T58M) mice, total Ncc and p-Ncc protein levels decreased and the GS phenotype persisted over the hypertensive phenotype. Overall, these data suggest that SPAK-mediated phosphorylation of NCC at T60 regulates NCC stability and function, and defective phosphorylation at this residue corrects the phenotype of pseudohypoaldosteronism type II.

  12. GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 2: User's Manual

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, B. D.; Mueller, C.; Necker, G. A.; Travis, J. R.; Spore, J. W.; Lam, K. L.; Royl, P.; Wilson, T. L.

    1998-10-01

    Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best-estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containment and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included. Volume III

  13. Calculation of Sodium Fire Test-I (Run-E6) using sodium combustion analysis code ASSCOPS version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Nakagiri, Toshio; Ohno, Shuji; Miyake, Osamu [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-11-01

    The calculation of Sodium Fire Test-I (Run-E6) was performed using the ASSCOPS (Analysis of Simultaneous Sodium Combustions in Pool and Spray) code version 2.0 in order to determine the parameters used in the code for the calculations of sodium combustion behavior of small or medium scale sodium leak, and to validate the applicability of the code. The parameters used in the code were determined and the validation of the code was confirmed because calculated temperatures, calculated oxygen concentration and other calculated values almost agreed with the test results. (author)

  14. DEVELOPING OF A NEW COMPREHENSIVE SPARK IGNITION ENGINES CODE FOR HEAT LOSS ANALYSIS WITHIN COMBUSTION CHAMBER WALLS

    Directory of Open Access Journals (Sweden)

    Shahram Khalilarya

    2010-01-01

    Full Text Available The objective of this work is to develop the existing a zero-dimensional model named ODES to provide detailed insights into the internal process of the modern high speed spark ignition engines. Therefore, it has been concentrated on the development of new sub models for incorporation in an extended form of ODES, as follows: - the existing semi-empirical combustion model has been replaced by a new comprehensive model, which is based on the turbulent flame speed in the combustion chamber. - the existing three wall heat transfer model has been replaced by a new one in which, the combustion chamber is divided in to three zones including cylinder head, cylinder wall, and piston head. The steady-state heat transfer equation is solved through finite difference method with replaced boundary and initial conditions. The results gave the temperature distribution of combustion chamber walls. The rate of heat losses from combustion chamber to the coolant is calculated by using the mean temperature of each part. The code has been extensively validated with respect to performance and heat transfer against experimental results obtained on XU7JP spark ignition engine with two kinds of fuel, gasoline and compresed natural gas and gave good agreement with available experimental.

  15. Nanocrystalline cellulose (NCC) reinforced alginate based biodegradable nanocomposite film.

    Science.gov (United States)

    Huq, Tanzina; Salmieri, Stephane; Khan, Avik; Khan, Ruhul A; Le Tien, Canh; Riedl, Bernard; Fraschini, Carole; Bouchard, Jean; Uribe-Calderon, Jorge; Kamal, Musa R; Lacroix, Monique

    2012-11-06

    Nanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control. Incorporation of NCC also significantly improved water vapor permeability (WVP) of the nanocomposite showing a 31% decrease due to 5 wt% NCC loading. Molecular interactions between alginate and NCC were supported by Fourier Transform Infrared Spectroscopy. The X-ray diffraction studies also confirmed the appearance of crystalline peaks due to the presence of NCC inside the films. Thermal stability of alginate-based nanocomposite films was improved after incorporation of NCC. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. NESREA AND NCC REGULATIONS ON TELECOMMUNICATION ...

    African Journals Online (AJOL)

    munication masts are injurious to human health and the environment. The ... contended further that the MTN base station had met NCC's regulation of five metres set ..... food is to the body', yet there are claims that these electromagnetic radia- ... are so low that the temperature increases are insignificant and do not affect.

  17. Analysis of the microturbine combustion chamber by using the CHEMKIN III computer code; Analise da camara de combustao de microturbinas empregando-se o codigo computacional CHEMKIN III

    Energy Technology Data Exchange (ETDEWEB)

    Madela, Vinicius Zacarias; Pauliny, Luis F. de A.; Veras, Carlos A. Gurgel [Brasilia Univ., DF (Brazil). Dept. de Engenharia Mecanica]. E-mail: gurgel@enm.unb.br; Costa, Fernando de S. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: fernando@cptec.inpe.br

    2000-07-01

    This work presents the results obtained with the simulation of multi fuel micro turbines combustion chambers. In particular, the predictions for the methane and Diesel burning are presented. The appropriate routines of the CHEMKIN III computer code were used.

  18. Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533.

    Science.gov (United States)

    Hertzberger, Rosanne Y; Pridmore, R David; Gysler, Christof; Kleerebezem, Michiel; Teixeira de Mattos, M Joost

    2013-01-01

    Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533. The probiotic Lactobacillus johnsonii NCC 533 is relatively sensitive to oxidative stress; the presence of oxygen causes a lower biomass yield due to early growth stagnation. We show however that oxygen can also be beneficial to this organism as it relieves the requirement for acetate and CO2 during growth. Both on agar- and liquid-media, anaerobic growth of L. johnsonii NCC 533 requires CO2 supplementation of the gas phase. Switching off the CO2 supply induces growth arrest and cell death. The presence of molecular oxygen overcomes the CO2 dependency. Analogously, L. johnsonii NCC 533 strictly requires media with acetate to sustain anaerobic growth, although supplementation at a level that is 100-fold lower (120 microM) than the concentration in regular growth medium for lactobacilli already suffices for normal growth. Analogous to the CO2 requirement, oxygen supply relieves this acetate-dependency for growth. The L. johnsonii NCC 533 genome indicates that this organism lacks genes coding for pyruvate formate lyase (PFL) and pyruvate dehydrogenase (PDH), both CO2 and acetyl-CoA producing systems. Therefore, C1- and C2- compound production is predicted to largely depend on pyruvate oxidase activity (POX). This proposed role of POX in C2/C1-generation is corroborated by the observation that in a POX deficient mutant of L. johnsonii NCC 533, oxygen is not able to overcome acetate dependency nor does it relieve the CO2 dependency.

  19. GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 1: Theory and Computational Model

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, B.D.; Mueller, C.; Necker, G.A.; Travis, J.R.; Spore, J.W.; Lam, K.L.; Royl, P.; Redlinger, R.; Wilson, T.L.

    1998-10-01

    Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best-estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containments and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior (1) in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and (2) during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included

  20. Network Control Center User Planning System (NCC UPS)

    Science.gov (United States)

    Dealy, Brian

    1991-01-01

    NCC UPS is presented in the form of the viewgraphs. The following subject areas are covered: UPS overview; NCC UPS role; major NCC UPS functional requirements; interactive user access levels; UPS interfaces; interactive user subsystem; interface navigation; scheduling screen hierarchy; interactive scheduling input panels; autogenerated schedule request panel; schedule data tabular display panel; schedule data graphic display panel; graphic scheduling aid design; and schedule data graphic display.

  1. NCC toodab korruselamuid tehases / tõlk. Mait Eelrand

    Index Scriptorium Estoniae

    2006-01-01

    Komplett-ehituskontseptsioonist. Komplett-tehnoloogia alusel on alustatud korruselamute tööstuslikku tootmist Rootsis Hallstahammaris paiknevas tehases. Soome NCC juhataja Timo U. Korhonen Komplett-majade arvatavast jõudmisest Soome. NCC Ehitus AS-i juhatuse liige Jaan Lehtsaar uuest kontseptsioonist

  2. NCC toodab korruselamuid tehases / tõlk. Mait Eelrand

    Index Scriptorium Estoniae

    2006-01-01

    Komplett-ehituskontseptsioonist. Komplett-tehnoloogia alusel on alustatud korruselamute tööstuslikku tootmist Rootsis Hallstahammaris paiknevas tehases. Soome NCC juhataja Timo U. Korhonen Komplett-majade arvatavast jõudmisest Soome. NCC Ehitus AS-i juhatuse liige Jaan Lehtsaar uuest kontseptsioonist

  3. NCC simulation model. Phase 2: Simulating the operations of the Network Control Center and NCC message manual

    Science.gov (United States)

    Benjamin, Norman M.; Gill, Tepper; Charles, Mary

    1994-01-01

    The network control center (NCC) provides scheduling, monitoring, and control of services to the NASA space network. The space network provides tracking and data acquisition services to many low-earth orbiting spacecraft. This report describes the second phase in the development of simulation models for the FCC. Phase one concentrated on the computer systems and interconnecting network.Phase two focuses on the implementation of the network message dialogs and the resources controlled by the NCC. Performance measures were developed along with selected indicators of the NCC's operational effectiveness.The NCC performance indicators were defined in terms of the following: (1) transfer rate, (2) network delay, (3) channel establishment time, (4) line turn around time, (5) availability, (6) reliability, (7) accuracy, (8) maintainability, and (9) security. An NCC internal and external message manual is appended to this report.

  4. Phosphorylation decreases ubiquitylation of the thiazide-sensitive cotransporter NCC and subsequent clathrin-mediated endocytosis.

    Science.gov (United States)

    Rosenbaek, Lena L; Kortenoeven, Marleen L A; Aroankins, Takwa S; Fenton, Robert A

    2014-05-09

    The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20-30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT.

  5. Phosphorylation Decreases Ubiquitylation of the Thiazide-sensitive Cotransporter NCC and Subsequent Clathrin-mediated Endocytosis*

    Science.gov (United States)

    Rosenbaek, Lena L.; Kortenoeven, Marleen L. A.; Aroankins, Takwa S.; Fenton, Robert A.

    2014-01-01

    The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20–30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT. PMID:24668812

  6. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC

    DEFF Research Database (Denmark)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B

    2012-01-01

    DAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin-angiotensin-aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1......The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho...

  7. Neuro-endoscopic management of intraventricular neurocysticercosis (NCC).

    Science.gov (United States)

    Husain, M; Jha, D K; Rastogi, M; Husain, N; Gupta, R K

    2007-01-01

    Various approaches including endoscopy have been used for the treatment of intraventricular and cisternal NCC. We present our technique of Neuro-endoscopic management of intraventricular NCC. Twenty-one cases, 13 females and 8 males (age range 12-50 years; mean, 25.7 years), of intraventricular NCC [lateral (n = 6), third (n = 6), fourth (n = 10) ventricles including a patient with both lateral and third ventricular cysts] producing obstructive hydrocephalus formed the group of study. Gaab Universal Endoscope System along with 4 mm 0 degrees and 30 degrees rigid telescopes were used through a frontal burr-hole for removal of intraventricular including intra-fourth ventricular (n = 10) NCC. Endoscopic third ventriculostomy (ETV) was done for internal cerebrospinal fluid (CSF) diversion. Average follow up was 18 months. Complete (n = 18) or partial (n = 2) removal of NCC was done in 20 patients, while a cyst located at foramen of Monro slipped and migrated to occipital or temporal horn in 1 patient. Thirty-degree 4-mm rigid telescope provided excellent image quality with ability to address even intra-fourth ventricular NCC through the dilated aqueduct using a curved tip catheter. No patient required further surgery for their hydrocephalus. There was no operative complication and post-operative ventriculitis was not seen in any case despite partial removal of NCC. Neuro-endoscopic surgery is an effective treatment modality for patients with intraventricular NCC. It effectively restores CSF flow and is capable of removing cysts completely or partially from accessible locations causing mass effect. Partial removal or rupture of the cyst does not affect the clinical outcome of the patients.

  8. Numerical Study of Outlet Boundary Conditions for Unsteady Turbulent Internal Flows Using the NCC

    Science.gov (United States)

    Liu, Nan-Suey; Shih, Tsan-Hsing

    2009-01-01

    This paper presents the results of studies on the outlet boundary conditions for turbulent internal flow simulations. Several outlet boundary conditions have been investigated by applying the National Combustion Code (NCC) to the configuration of a LM6000 single injector flame tube. First of all, very large eddy simulations (VLES) have been performed using the partially resolved numerical simulation (PRNS) approach, in which both the nonlinear and linear dynamic subscale models were employed. Secondly, unsteady Reynolds averaged Navier- Stokes (URANS) simulations have also been performed for the same configuration to investigate the effects of different outlet boundary conditions in the context of URANS. Thirdly, the possible role of the initial condition is inspected by using three different initial flow fields for both the PRNS/VLES simulation and the URANS simulation. The same grid is used for all the simulations and the number of mesh element is about 0.5 million. The main purpose of this study is to examine the long-time behavior of the solution as determined by the imposed outlet boundary conditions. For a particular simulation to be considered as successful under the given initial and boundary conditions, the solution must be sustainable in a physically meaningful manner over a sufficiently long period of time. The commonly used outlet boundary condition for steady Reynolds averaged Navier-Stokes (RANS) simulation is a fixed pressure at the outlet with all the other dependent variables being extrapolated from the interior. The results of the present study suggest that this is also workable for the URANS simulation of the LM6000 injector flame tube. However, it does not work for the PRNS/VLES simulation due to the unphysical reflections of the pressure disturbances at the outlet boundary. This undesirable situation can be practically alleviated by applying a simple unsteady convection equation for the pressure disturbances at the outlet boundary. The

  9. Aldosterone Modulates the Association between NCC and ENaC.

    Science.gov (United States)

    Wynne, Brandi M; Mistry, Abinash C; Al-Khalili, Otor; Mallick, Rickta; Theilig, Franziska; Eaton, Douglas C; Hoover, Robert S

    2017-06-23

    Distal sodium transport is a final step in the regulation of blood pressure. As such, understanding how the two main sodium transport proteins, the thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC), are regulated is paramount. Both are expressed in the late distal nephron; however, no evidence has suggested that these two sodium transport proteins interact. Recently, we established that these two sodium transport proteins functionally interact in the second part of the distal nephron (DCT2). Given their co-localization within the DCT2, we hypothesized that NCC and ENaC interactions might be modulated by aldosterone (Aldo). Aldo treatment increased NCC and αENaC colocalization (electron microscopy) and interaction (coimmunoprecipitation). Finally, with co-expression of the Aldo-induced protein serum- and glucocorticoid-inducible kinase 1 (SGK1), NCC and αENaC interactions were increased. These data demonstrate that Aldo promotes increased interaction of NCC and ENaC, within the DCT2 revealing a novel method of regulation for distal sodium reabsorption.

  10. Investigation on effect of equivalence ratio and engine speed on homogeneous charge compression ignition combustion using chemistry based CFD code

    Directory of Open Access Journals (Sweden)

    Ghafouri Jafar

    2014-01-01

    Full Text Available Combustion in a large-bore natural gas fuelled diesel engine operating under Homogeneous Charge Compression Ignition mode at various operating conditions is investigated in the present paper. Computational Fluid Dynamics model with integrated chemistry solver is utilized and methane is used as surrogate of natural gas fuel. Detailed chemical kinetics mechanism is used for simulation of methane combustion. The model results are validated using experimental data by Aceves, et al. (2000, conducted on the single cylinder Volvo TD100 engine operating at Homogeneous Charge Compression Ignition conditions. After verification of model predictions using in-cylinder pressure histories, the effect of varying equivalence ratio and engine speed on combustion parameters of the engine is studied. Results indicate that increasing engine speed provides shorter time for combustion at the same equivalence ratio such that at higher engine speeds, with constant equivalence ratio, combustion misfires. At lower engine speed, ignition delay is shortened and combustion advances. It was observed that increasing the equivalence ratio retards the combustion due to compressive heating effect in one of the test cases at lower initial pressure. Peak pressure magnitude is increased at higher equivalence ratios due to higher energy input.

  11. Turbulent Chemical Interaction Models in NCC: Comparison

    Science.gov (United States)

    Norris, Andrew T.; Liu, Nan-Suey

    2006-01-01

    The performance of a scalar PDF hydrogen-air combustion model in predicting a complex reacting flow is evaluated. In addition the results are compared to those obtained by running the same case with the so-called laminar chemistry model and also a new model based on the concept of mapping partially stirred reactor data onto perfectly stirred reactor data. The results show that the scalar PDF model produces significantly different results from the other two models, and at a significantly higher computational cost.

  12. A model of turbocharger radial turbines appropriate to be used in zero- and one-dimensional gas dynamics codes for internal combustion engines modelling

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, J.R.; Arnau, F.J.; Dolz, V.; Tiseira, A. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Cervello, C. [Conselleria de Cultura, Educacion y Deporte, Generalitat Valenciana (Spain)

    2008-12-15

    The paper presents a model of fixed and variable geometry turbines. The aim of this model is to provide an efficient boundary condition to model turbocharged internal combustion engines with zero- and one-dimensional gas dynamic codes. The model is based from its very conception on the measured characteristics of the turbine. Nevertheless, it is capable of extrapolating operating conditions that differ from those included in the turbine maps, since the engines usually work within these zones. The presented model has been implemented in a one-dimensional gas dynamic code and has been used to calculate unsteady operating conditions for several turbines. The results obtained have been compared with success against pressure-time histories measured upstream and downstream of the turbine during on-engine operation. (author)

  13. National Counterdrug Center (NCC) Simulation System Operational Requirements Document (ORD) Version 2

    Energy Technology Data Exchange (ETDEWEB)

    Holter, Gregory M.

    2001-01-26

    This Operational Requirements Document (ORD) describes the capabilities that need to be incorporated in the NCC interactive simulation system being developed under the auspices of the NCC development program. The ORD addresses the necessary capabilities (i.e. what the system needs to be able to do); it defines the envelope of situations and circumstances that the NCC system must be able to represent and operate within. The NCC system will be developed in modules over a period of several years. This ORD, Version 2, supersedes the previous version. Future updates of this ORD are anticipated to be issued as needed to guide the development of later versions of the NCC system.

  14. National Counterdrug Center (NCC) Simulation System Operational Requirements Document (ORD) Version 2

    Energy Technology Data Exchange (ETDEWEB)

    Holter, Gregory M

    2001-01-26

    This Operational Requirements Document (ORD) describes the capabilities that need to be incorporated in the NCC interactive simulation system being developed under the auspices of the NCC development program. The ORD addresses the necessary capabilities (i.e. what the system needs to be able to do); it defines the envelope of situations and circumstances that the NCC system must be able to represent and operate within. The NCC system will be developed in modules over a period of several years. This ORD, Version 2, supersedes the previous version. Future updates of this ORD are anticipated to be issued as needed to guide the development of later versions of the NCC system.

  15. Aldosterone acutely stimulates NCC activity via a SPAK-mediated pathway.

    Science.gov (United States)

    Ko, Benjamin; Mistry, Abinash C; Hanson, Lauren; Mallick, Rickta; Wynne, Brandi M; Thai, Tiffany L; Bailey, James L; Klein, Janet D; Hoover, Robert S

    2013-09-01

    Hypertension is a leading cause of morbidity and mortality worldwide, and disordered sodium balance has long been implicated in its pathogenesis. Aldosterone is perhaps the key regulator of sodium balance and thus blood pressure. The sodium chloride cotransporter (NCC) in the distal convoluted tubule of the kidney is a major site of sodium reabsorption and plays a key role in blood pressure regulation. Chronic exposure to aldosterone increases NCC protein expression and function. However, more acute effects of aldosterone on NCC are unknown. In our salt-abundant modern society where chronic salt deprivation is rare, understanding the acute effects of aldosterone is critical. Here, we examined the acute effects (12-36 h) of aldosterone on NCC in the rodent kidney and in a mouse distal convoluted tubule cell line. Studies demonstrated that aldosterone acutely stimulated NCC activity and phosphorylation without affecting total NCC abundance or surface expression. This effect was dependent upon the presence of the mineralocorticoid receptor and serum- and glucocorticoid-regulated kinase 1 (SGK1). Furthermore, STE20/SPS-1-related proline/alanine-rich kinase (SPAK) phosphorylation also increased, and gene silencing of SPAK eliminated the effect of aldosterone on NCC activity. Aldosterone administration via a minipump in adrenalectomized rodents confirmed an increase in NCC phosphorylation without a change in NCC total protein. These data indicate that acute aldosterone-induced SPAK-dependent phosphorylation of NCC increases individual transporter activity.

  16. A seismic field test with a Low-level Acoustic Combustion Source and Pseudo-Noise codes

    Science.gov (United States)

    Askeland, Bjørn; Ruud, Bent Ole; Hobæk, Halvor; Mjelde, Rolf

    2009-01-01

    The Low-level Acoustic Combustion Source (LACS) which can fire its pulses at a high rate, has been tested successfully as a seismic marine source on shallow ice-age sediments in Byfjorden at Bergen, Norway. Pseudo-Noise pulsed signals with spiky autocorrelation functions were used to detect the sediments. Each transmitted sequence lasted 10 s and contained 43 pulses. While correlation gave a blurry result, deconvolution between the near-field recordings and the streamer recordings gave a clear seismic section. Compared to the section acquired with single air-gun shots along the same profile, the LACS gave a more clear presentation of the sediments and basement.

  17. Functionomics of NCC mutations in Gitelman syndrome using a novel mammalian cell-based activity assay.

    Science.gov (United States)

    Valdez-Flores, Marco A; Vargas-Poussou, Rosa; Verkaart, Sjoerd; Tutakhel, Omar A Z; Valdez-Ortiz, Angel; Blanchard, Anne; Treard, Cyrielle; Hoenderop, Joost G J; Bindels, René J M; Jeleń, Sabina

    2016-12-01

    Gitelman syndrome (GS) is an autosomal recessive salt-wasting tubular disorder resulting from loss-of-function mutations in the thiazide-sensitive NaCl cotransporter (NCC). Functional analysis of these mutations has been limited to the use of Xenopus laevis oocytes. The aim of the present study was, therefore, to analyze the functional consequences of NCC mutations in a mammalian cell-based assay, followed by analysis of mutated NCC protein expression as well as glycosylation and phosphorylation profiles using human embryonic kidney (HEK) 293 cells. NCC activity was assessed with a novel assay based on thiazide-sensitive iodide uptake in HEK293 cells expressing wild-type or mutant NCC (N59I, R83W, I360T, C421Y, G463R, G731R, L859P, or R861C). All mutations caused a significantly lower NCC activity. Immunoblot analysis of the HEK293 cells revealed that 1) all NCC mutants have decreased NCC protein expression; 2) mutant N59I, R83W, I360T, C421Y, G463R, and L859P have decreased NCC abundance at the plasma membrane; 3) mutants C421Y and L859P display impaired NCC glycosylation; and 4) mutants N59I, R83W, C421Y, C731R, and L859P show affected NCC phosphorylation. In conclusion, we developed a mammalian cell-based assay in which NCC activity assessment together with a profiling of mutated protein processing aid our understanding of the pathogenic mechanism of the NCC mutations. Copyright © 2016 the American Physiological Society.

  18. Spherical nanocrystalline cellulose (NCC) from oil palm empty fruit bunch pulp via ultrasound assisted hydrolysis.

    Science.gov (United States)

    Zianor Azrina, Z A; Beg, M Dalour H; Rosli, M Y; Ramli, Ridzuan; Junadi, Norhafzan; Alam, A K M Moshiul

    2017-04-15

    Nanocrystalline cellulose (NCC) was isolated from oil palm empty fruit bunch pulp (EFBP) using ultrasound assisted acid hydrolysis. The obtained NCC was analysed using FESEM, XRD, FTIR, and TGA, and compared with raw empty fruit bunch fibre (REFB), empty fruit bunch pulp (EFBP), and treated empty fruit bunch pulp (TEFBP). Based on FESEM analysis, it was found that NCC has a spherical shaped after acid hydrolysis with the assistance of ultrasound. This situation was different compared to previous studies that obtained rod-like shaped of NCC. Furthermore, the crystallinity of NCC is higher compared to REFB and EFBP. According to thermal stability, the NCC obtained shows remarkable sign of high thermal stability compared to REFB and EFBP.

  19. Exploring the intricate regulatory network controlling the thiazide-sensitive NaCl cotransporter (NCC).

    Science.gov (United States)

    Dimke, Henrik

    2011-12-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays key roles in renal electrolyte transport and blood pressure maintenance. Regulation of this cotransporter has received increased attention recently, prompted by the discovery that mutations in the with-no-lysine (WNK) kinases are the molecular explanation for pseudohypoaldosteronism type II (PHAII). Studies suggest that WNK4 regulates NCC via two distinct pathways, depending on its state of activation. Furthermore, an intact STE20-related proline-alanine-rich kinase (SPAK)/oxidative stress response 1 kinase (OSR1) pathway was found to be necessary for a WNK4 PHAII mutation to increase NCC phosphorylation and blood pressure in mice. The mouse protein 25α is a novel regulator of the SPAK/OSR1 kinase family, which greatly increases their activity. The phosphorylation status of NCC and the WNK is regulated by the serum- and glucocorticoid-inducible kinase 1, suggesting novel mechanisms whereby aldosterone modulates NCC activity. Dephosphorylation of NCC by protein phosphatase 4 strongly influences the activity of the cotransporter, confirming an important role for NCC phosphorylation. Finally, γ-adducin increases NCC activity. This stimulatory effect is dependent on the phosphorylation status of the cotransporter. γ-Adducin only binds the dephosphorylated cotransporter, suggesting that phosphorylation of NCC causes the dissociation of γ-adducin. Since γ-adducin is not a kinase, it is tempting to speculate that the protein exerts its function by acting as a scaffold between the dephosphorylated cotransporter and the regulatory kinase. As more molecular regulators of NCC are identified, the system-controlling NCC activity is becoming increasingly complex. This intricacy confers an ability to integrate a variety of stimuli, thereby regulating NCC transport activity and ultimately blood pressure.

  20. Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells.

    Science.gov (United States)

    Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna; Staub, Olivier; Fenton, Robert A

    2017-08-01

    The thiazide-sensitive sodium chloride cotransporter NCC is important for maintaining serum sodium (Na(+)) and, indirectly, serum potassium (K(+)) levels. Functional studies on NCC have used cell lines with native NCC expression, transiently transfected nonpolarized cell lines, or Xenopus laevis oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust thiazide-sensitive and chloride dependent sodium-22 ((22)Na) uptake from the apical side. To minimize cost and maximize throughput, assays were modified to use cells grown on plastic. On plastic, cells had similar thiazide-sensitive (22)Na uptakes that increased following preincubation of cells in chloride-free solutions. NCC was detected in the plasma membrane, and both membrane abundance and phosphorylation of NCC were increased by incubation in chloride-free solutions. Furthermore, in cells exposed for 15 min to low or high extracellular K(+), the levels of phosphorylated NCC increased and decreased, respectively. To demonstrate that the system allows rapid and systematic assessment of mutated NCC, three phosphorylation sites in NCC were mutated, and NCC activity was examined. (22)Na fluxes in phosphorylation-deficient mutants were reduced to baseline levels, whereas phosphorylation-mimicking mutants were constitutively active, even without chloride-free stimulation. In conclusion, this system allows the activity, cellular localization, and abundance of wild-type or mutant NCC to be examined in the same polarized mammalian expression system in a rapid, easy, and low-cost fashion. Copyright © 2017 the American Physiological Society.

  1. Exploring the intricate regulatory network controlling the thiazide-sensitive NaCl cotransporter (NCC)

    DEFF Research Database (Denmark)

    Dimke, Henrik Anthony

    2011-01-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays key roles in renal electrolyte transport and blood pressure maintenance. Regulation of this cotransporter has received increased attention recently, prompted by the discovery that mutations in the with-no-lysine (WNK) kinases are the molecular...... by acting as a scaffold between the dephosphorylated cotransporter and the regulatory kinase. As more molecular regulators of NCC are identified, the system-controlling NCC activity is becoming increasingly complex. This intricacy confers an ability to integrate a variety of stimuli, thereby regulating NCC...

  2. WNK4 enhances the degradation of NCC through a sortilin-mediated lysosomal pathway.

    Science.gov (United States)

    Zhou, Bo; Zhuang, Jieqiu; Gu, Dingying; Wang, Hua; Cebotaru, Liudmila; Guggino, William B; Cai, Hui

    2010-01-01

    WNK kinase is a serine/threonine kinase that plays an important role in electrolyte homeostasis. WNK4 significantly inhibits the surface expression of the sodium chloride co-transporter (NCC) by enhancing the degradation of NCC through a lysosomal pathway, but the mechanisms underlying this trafficking are unknown. Here, we investigated the effect of the lysosomal targeting receptor sortilin on NCC expression and degradation. In Cos-7 cells, we observed that the presence of WNK4 reduced the steady-state amount of NCC by approximately half. Co-transfection with truncated sortilin (a dominant negative mutant) prevented this WNK4-induced reduction in NCC. NCC immunoprecipitated with both wild-type sortilin and, to a lesser extent, truncated sortilin. Immunostaining revealed that WNK4 increased the co-localization of NCC with the lysosomal marker cathepsin D, and NCC co-localized with wild-type sortilin, truncated sortilin, and WNK4 in the perinuclear region. These findings suggest that WNK4 promotes NCC targeting to the lysosome for degradation via a mechanism involving sortilin.

  3. WNK4 is the major WNK positively regulating NCC in the mouse kidney.

    Science.gov (United States)

    Takahashi, Daiei; Mori, Takayasu; Nomura, Naohiro; Khan, Muhammad Zakir Hossain; Araki, Yuya; Zeniya, Moko; Sohara, Eisei; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2014-05-09

    By analysing the pathogenesis of a hereditary hypertensive disease, PHAII (pseudohypoaldosteronism type II), we previously discovered that WNK (with-no-lysine kinase)-OSR1/SPAK (oxidative stress-responsive 1/Ste20-like proline/alanine-rich kinase) cascade regulates NCC (Na-Cl co-transporter) in the DCT (distal convoluted tubules) of the kidney. However, the role of WNK4 in the regulation of NCC remains controversial. To address this, we generated and analysed WNK4-/- mice. Although a moderate decrease in SPAK phosphorylation and a marked increase in WNK1 expression were evident in the kidneys of WNK4-/- mice, the amount of phosphorylated and total NCC decreased to almost undetectable levels, indicating that WNK4 is the major WNK positively regulating NCC, and that WNK1 cannot compensate for WNK4 deficiency in the DCT. Insulin- and low-potassium diet-induced NCC phosphorylation were abolished in WNK4-/- mice, establishing that both signals to NCC were mediated by WNK4. As shown previously, a high-salt diet decreases phosphorylated and total NCC in WNK4+/+ mice via AngII (angiotensin II) and aldosterone suppression. This was not ameliorated by WNK4 knock out, excluding the negative regulation of WNK4 on NCC postulated to be active in the absence of AngII stimulation. Thus, WNK4 is the major positive regulator of NCC in the kidneys.

  4. Characterization of a novel phosphorylation site in the sodium–chloride cotransporter, NCC

    Science.gov (United States)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B; MacAulay, N; Fenton, R A

    2012-01-01

    The sodium–chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antibodies targeting pS124-NCC demonstrated a band of 160 kDa in the kidney cortex, but not medulla, which was preabsorbed by a corresponding phosphorylated peptide. Confocal microscopy with kidney tubule segment-specific markers localized pS124-NCC to all distal convoluted tubule cells. Double immunogold electron microscopy demonstrated that pS124-NCC co-localized with total NCC in the apical plasma membrane of distal convoluted tubule cells and intracellular vesicles. Acute treatment of Munich–Wistar rats or vasopressin-deficient Brattleboro rats with the vasopressin type 2 receptor-specific agonist dDAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin–angiotensin–aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1-related proline–alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and mTOR/FRAP) showed weak but significant phosphorylation activity at S124. In oocytes, 36Cl uptake studies combined with biochemical analysis showed decreased activity of plasma membrane-associated NCC when replacing S124 with alanine (A) or aspartic acid (D). In novel tetracycline-inducible MDCKII-NCC cell lines, S124A and S124D mutants were able to traffic to the plasma membrane similarly to wildtype NCC. PMID:22966159

  5. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC.

    Science.gov (United States)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B; MacAulay, N; Fenton, R A

    2012-12-01

    The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antibodies targeting pS124-NCC demonstrated a band of 160 kDa in the kidney cortex, but not medulla, which was preabsorbed by a corresponding phosphorylated peptide. Confocal microscopy with kidney tubule segment-specific markers localized pS124-NCC to all distal convoluted tubule cells. Double immunogold electron microscopy demonstrated that pS124-NCC co-localized with total NCC in the apical plasma membrane of distal convoluted tubule cells and intracellular vesicles. Acute treatment of Munich-Wistar rats or vasopressin-deficient Brattleboro rats with the vasopressin type 2 receptor-specific agonist dDAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin-angiotensin-aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1-related proline-alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and mTOR/FRAP) showed weak but significant phosphorylation activity at S124. In oocytes, (36)Cl uptake studies combined with biochemical analysis showed decreased activity of plasma membrane-associated NCC when replacing S124 with alanine (A) or aspartic acid (D). In novel tetracycline-inducible MDCKII-NCC cell lines, S124A and S124D mutants were able to traffic to the plasma membrane similarly to wildtype NCC.

  6. NCC izgotavlivajet na zavode mnogo-etazhnõje doma / tõlk. Mait Eelrand

    Index Scriptorium Estoniae

    2006-01-01

    Komplett-ehituskontseptsioonist. Komplett-tehnoloogia alusel on alustatud korruselamute tööstuslikku tootmist Rootsis Hallstahammaris paiknevas tehases. Soome NCC juhataja Timo U. Korhonen Komplett-majade arvatavast jõudmisest Soome. NCC Ehitus AS-i juhatuse liige Jaan Lehtsaar uuest kontseptsioonist

  7. Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells

    DEFF Research Database (Denmark)

    Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna

    2017-01-01

    oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust...

  8. Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533

    NARCIS (Netherlands)

    Hertzberger, R.Y.; Pridmore, R.D.; Gysler, C.; Kleerebezem, M.; Teixeira de Mattos, M.J.

    2013-01-01

    Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533. The probiotic Lactobacillus johnsonii NCC 533 is relatively sensitive to oxidative stress; the presence of oxygen causes a lower biomass yield due to early growth stagnation. We show however that oxygen can also be

  9. NCC izgotavlivajet na zavode mnogo-etazhnõje doma / tõlk. Mait Eelrand

    Index Scriptorium Estoniae

    2006-01-01

    Komplett-ehituskontseptsioonist. Komplett-tehnoloogia alusel on alustatud korruselamute tööstuslikku tootmist Rootsis Hallstahammaris paiknevas tehases. Soome NCC juhataja Timo U. Korhonen Komplett-majade arvatavast jõudmisest Soome. NCC Ehitus AS-i juhatuse liige Jaan Lehtsaar uuest kontseptsioonist

  10. Modulation of NCC activity by low and high K+ intake: insights into the signaling pathways involved

    Science.gov (United States)

    Castañeda-Bueno, María; Cervantes-Perez, Luz Graciela; Rojas-Vega, Lorena; Arroyo-Garza, Isidora; Vázquez, Norma; Moreno, Erika

    2014-01-01

    Modulation of Na+-Cl− cotransporter (NCC) activity is essential to adjust K+ excretion in the face of changes in dietary K+ intake. We used previously characterized genetic mouse models to assess the role of Ste20-related proline-alanine-rich kinase (SPAK) and with-no-lysine kinase (WNK)4 in the modulation of NCC by K+ diets. SPAK knockin and WNK4 knockout mice were placed on normal-, low-, or high-K+-citrate diets for 4 days. The low-K+ diet decreased and high-K+ diet increased plasma aldosterone levels, but both diets were associated with increased phosphorylation of NCC (phospho-NCC, Thr44/Thr48/Thr53) and phosphorylation of SPAK/oxidative stress responsive kinase 1 (phospho-SPAK/OSR1, Ser383/Ser325). The effect of the low-K+ diet on SPAK phosphorylation persisted in WNK4 knockout and SPAK knockin mice, whereas the effects of ANG II on NCC and SPAK were lost in both mouse colonies. This suggests that for NCC activation by ANG II, integrity of the WNK4/SPAK pathway is required, whereas for the low-K+ diet, SPAK phosphorylation occurred despite the absence of WNK4, suggesting the involvement of another WNK (WNK1 or WNK3). Additionally, because NCC activation also occurred in SPAK knockin mice, it is possible that loss of SPAK was compensated by OSR1. The positive effect of the high-K+ diet was observed when the accompanying anion was citrate, whereas the high-KCl diet reduced NCC phosphorylation. However, the effect of the high-K+-citrate diet was aldosterone dependent, and neither metabolic alkalosis induced by bicarbonate, nor citrate administration in the absence of K+ increased NCC phosphorylation, suggesting that it was not due to citrate-induced metabolic alkalosis. Thus, the accompanying anion might modulate the NCC response to the high-K+ diet. PMID:24761002

  11. Modulation of NCC activity by low and high K(+) intake: insights into the signaling pathways involved.

    Science.gov (United States)

    Castañeda-Bueno, María; Cervantes-Perez, Luz Graciela; Rojas-Vega, Lorena; Arroyo-Garza, Isidora; Vázquez, Norma; Moreno, Erika; Gamba, Gerardo

    2014-06-15

    Modulation of Na(+)-Cl(-) cotransporter (NCC) activity is essential to adjust K(+) excretion in the face of changes in dietary K(+) intake. We used previously characterized genetic mouse models to assess the role of Ste20-related proline-alanine-rich kinase (SPAK) and with-no-lysine kinase (WNK)4 in the modulation of NCC by K(+) diets. SPAK knockin and WNK4 knockout mice were placed on normal-, low-, or high-K(+)-citrate diets for 4 days. The low-K(+) diet decreased and high-K(+) diet increased plasma aldosterone levels, but both diets were associated with increased phosphorylation of NCC (phospho-NCC, Thr(44)/Thr(48)/Thr(53)) and phosphorylation of SPAK/oxidative stress responsive kinase 1 (phospho-SPAK/OSR1, Ser(383)/Ser(325)). The effect of the low-K(+) diet on SPAK phosphorylation persisted in WNK4 knockout and SPAK knockin mice, whereas the effects of ANG II on NCC and SPAK were lost in both mouse colonies. This suggests that for NCC activation by ANG II, integrity of the WNK4/SPAK pathway is required, whereas for the low-K(+) diet, SPAK phosphorylation occurred despite the absence of WNK4, suggesting the involvement of another WNK (WNK1 or WNK3). Additionally, because NCC activation also occurred in SPAK knockin mice, it is possible that loss of SPAK was compensated by OSR1. The positive effect of the high-K(+) diet was observed when the accompanying anion was citrate, whereas the high-KCl diet reduced NCC phosphorylation. However, the effect of the high-K(+)-citrate diet was aldosterone dependent, and neither metabolic alkalosis induced by bicarbonate, nor citrate administration in the absence of K(+) increased NCC phosphorylation, suggesting that it was not due to citrate-induced metabolic alkalosis. Thus, the accompanying anion might modulate the NCC response to the high-K(+) diet. Copyright © 2014 the American Physiological Society.

  12. Mechanisms of angiotensin II stimulation of NCC are time-dependent in mDCT15 cells.

    Science.gov (United States)

    Ko, Benjamin; Mistry, Abinash; Hanson, Lauren; Mallick, Rickta; Hoover, Robert S

    2015-04-01

    Angiotensin II (ANG II) increases thiazide-sensitive sodium-chloride cotransporter (NCC) activity both acutely and chronically. ANG II has been implicated as a switch that turns WNK4 from an inhibitor of NCC into an activator of NCC, and ANG II's effect on NCC appears to require WNK4. Chronically, ANG II stimulation of NCC results in an increase in total and phosphorylated NCC, but the role of NCC phosphorylation in acute ANG II actions is unclear. Here, using a mammalian cell model with robust native NCC activity, we corroborate the role that ANG II plays in WNK4 regulation and clarify the role of Ste20-related proline alanine-rich kinase (SPAK)-induced NCC phosphorylation in ANG II action. ANG II was noted to have a biphasic effect on NCC, with a peak increase in NCC activity in the physiologic range of 10(-11) M ANG II. This effect was apparent as early as 15 min and remained sustained through 120 min. These changes correlated with significant increases in NCC surface protein expression. Knockdown of WNK4 expression sharply attenuated the effect of ANG II. SPAK knockdown did not affect ANG II action at early time points (15 and 30 min), but it did attenuate the response at 60 min. Correspondingly, NCC phosphorylation did not increase at 15 or 30 min, but increased significantly at 60 min. We therefore conclude that within minutes of an increase in ANG II, NCC is rapidly trafficked to the cell surface in a phosphorylation-independent but WNK4-dependent manner. Then, after 60 min, ANG II induces SPAK-dependent phosphorylation of NCC.

  13. SPAK-mediated NCC regulation in response to low-K+ diet.

    Science.gov (United States)

    Wade, James B; Liu, Jie; Coleman, Richard; Grimm, P Richard; Delpire, Eric; Welling, Paul A

    2015-04-15

    The NaCl cotransporter (NCC) of the renal distal convoluted tubule is stimulated by low-K(+) diet by an unknown mechanism. Since recent work has shown that the STE20/SPS-1-related proline-alanine-rich protein kinase (SPAK) can function to stimulate NCC by phosphorylation of specific N-terminal sites, we investigated whether the NCC response to low-K(+) diet is mediated by SPAK. Using phospho-specific antibodies in Western blot and immunolocalization studies of wild-type and SPAK knockout (SPAK(-/-)) mice fed a low-K(+) or control diet for 4 days, we found that low-K(+) diet strongly increased total NCC expression and phosphorylation of NCC. This was associated with an increase in total SPAK expression in cortical homogenates and an increase in phosphorylation of SPAK at the S383 activation site. The increased pNCC in response to low-K(+) diet was blunted but not completely inhibited in SPAK(-/-) mice. These findings reveal that SPAK is an important mediator of the increased NCC activation by phosphorylation that occurs in the distal convoluted tubule in response to a low-K(+) diet, but other low-potassium-activated kinases are likely to be involved. Copyright © 2015 the American Physiological Society.

  14. Cortisol regulates sodium homeostasis by stimulating the transcription of sodium-chloride transporter (NCC) in zebrafish (Danio rerio).

    Science.gov (United States)

    Lin, Chia-Hao; Hu, Huei-Jyun; Hwang, Pung-Pung

    2016-02-15

    In mammals, sodium/hydrogen exchanger (NHE) and sodium-chloride cotransporter (NCC) are expressed in renal tubules, and exhibit functional redundancy and mutual compensation in Na(+) uptake. In teleosts, the gills of the adult and skin of the embryonic stage function as external kidneys, and ionocytes are responsible for ionoregulation in these tissues. NHE- and NCC-expressing ionocytes mutually cooperate to adjust Na(+) uptake, which is analogous to the activity of the mammalian kidney. Cortisol is a hormone that controls Na(+) uptake through regulating NCC expression and activity in mammals; however, cortisol-mediated control of NCC expression is little understood in non-mammalian vertebrates, such as teleosts. It is essential for our understanding of the evolution of such regulation to determine whether cortisol has a conserved effect on NCC in vertebrates. In the present study, we treated zebrafish embryos with low Na(+) medium (LNa, 0.04 mM Na(+)) for 3 d to stimulate the mRNA expression of nhe3b, ncc, and cyp11b1 (a cortisol-synthesis enzyme) and whole body cortisol level. Exogenous cortisol treatment (20 mg/l, 3 d) resulted in an elevation of whole-body Na(+) content, ncc expression, and the density of ncc-expressing cells in zebrafish larvae. In loss-of-function experiments, microinjection of glucocorticoid receptor (gr) morpholino (MO) suppressed sodium content, ncc expression, and the density of ncc-expressing cells, but injection of mr MO had no such effects. In addition, exogenous cortisol treatment and gr MO injection also altered ncc expression and the density of ncc-expressing cells in gcm2 morphant larvae. Taken together, cortisol and GR appear to regulate Na(+) absorption through stimulating ncc expression and the differentiation of ncc-expressing ionocytes, providing new insights into the actions of cortisol on Na(+) uptake.

  15. Hydrogen peroxide production by Lactobacillus johnsonii NCC 533 and its role in anti-Salmonella activity.

    Science.gov (United States)

    Pridmore, Raymond David; Pittet, Anne-Cécile; Praplan, Fabienne; Cavadini, Christoph

    2008-06-01

    The human intestinal isolate Lactobacillus johnsonii NCC 533 (La1) is a probiotic strain with well-documented antimicrobial properties. Previous research has identified the production of lactic acid and bacteriocins as important factors, but that other unidentified factors are also involved. We used the recently published genome sequence of L. johnsonii NCC 533 to search for novel antipathogen factors and identified three potential gene products that may catalyze the synthesis of the known antimicrobial factor hydrogen peroxide, H(2)O(2). In this work, we confirmed the ability of NCC 533 as well as eight different L. johnsonii strains and Lactobacillus gasseri to produce H(2)O(2) when resting cells were incubated in the presence of oxygen, and that culture supernatant containing NCC 533-produced H(2)O(2) was effective in killing the model pathogen Salmonella enterica serovar Typhimurium SL1344 in vitro.

  16. Software metrics: The key to quality software on the NCC project

    Science.gov (United States)

    Burns, Patricia J.

    1993-01-01

    Network Control Center (NCC) Project metrics are captured during the implementation and testing phases of the NCCDS software development lifecycle. The metrics data collection and reporting function has interfaces with all elements of the NCC project. Close collaboration with all project elements has resulted in the development of a defined and repeatable set of metrics processes. The resulting data are used to plan and monitor release activities on a weekly basis. The use of graphical outputs facilitates the interpretation of progress and status. The successful application of metrics throughout the NCC project has been instrumental in the delivery of quality software. The use of metrics on the NCC Project supports the needs of the technical and managerial staff. This paper describes the project, the functions supported by metrics, the data that are collected and reported, how the data are used, and the improvements in the quality of deliverable software since the metrics processes and products have been in use.

  17. Liquid crystal behavior induced assembling fabrication of conductive chiral MWCNTs@NCC nanopaper

    Science.gov (United States)

    Ren, Yumei; Wang, Tianjiao; Chen, Zhimin; Li, Jing; Tian, Qiuge; Yang, Hongxia; Xu, Qun

    2016-11-01

    The conductive chiral MWCNTs@NCC nanopapers obtained by the assembly of nanocrystalline cellulose liquid crystals (NCC LCs) host matrix along with one-dimensional (1-D) multi-walled carbon nanotubes (MWCNTs) have been studied in this work. Circular dichroism (CD) studies show strong signals stemming from the chiral nematic structure. Notably, the introduction of the MWCNTs has a pronounced effect on the chiral structure of the as-prepared nanopaper. Our experimental results indicate the multiple weak molecular interactions existing between MWCNTs and NCC are responsible for the effective dispersion and stabilization of MWCNTs. Moreover it also confirms the resulting nanopaper has an increased conductivity of 4.2 S/m at 1.96 wt% MWCNTs. So the co-assembly of the nanocomposite herein opens a gateway for preparing functional materials combining the photonic properties of the NCC LCs matrix with other building blocks that can supply other advantageous functions.

  18. Neurocysticercosis (NCC) with Hydrocephalus, Optic Atrophy and Vision Loss: A Rare Presentation.

    Science.gov (United States)

    Chaudhary, Nagendra; Mahato, Shyam Kumar; Khan, Salamat; Pathak, Santosh; Bhatia, B D

    2015-02-01

    Neurocysticercosis (NCC) is one of the most common parasitic infestations (Taenia solium) of central nervous system (CNS) in children. Seizures are the common presenting symptoms. Hydrocephalus and optic atrophy are rare complications which may require neurosurgical interventions. We report a case of NCC with hydrocephalus and bilateral optic atrophy associated with vision loss in a Nepalese patient who improved with anti-parasitic therapy followed by ventriculo-peritoneal (VP) shunting.

  19. Liquid crystal behavior induced assembling fabrication of conductive chiral MWCNTs@NCC nanopaper

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yumei; Wang, Tianjiao; Chen, Zhimin; Li, Jing; Tian, Qiuge; Yang, Hongxia; Xu, Qun, E-mail: qunxu@zzu.edu.cn

    2016-11-01

    Highlights: • In this study conductive chiral MWCNTs@NCC nanopapers were prepared. • The introduction of the MWCNTs has a pronounced effect on the chiral structure of the as-prepared nanopaper. • The multiple weak molecular interactions existing between MWCNTs and NCC are responsible for the effective dispersion and stabilization of MWCNTs. • The resulting nanopaper has an increased conductivity. - Abstract: The conductive chiral MWCNTs@NCC nanopapers obtained by the assembly of nanocrystalline cellulose liquid crystals (NCC LCs) host matrix along with one-dimensional (1-D) multi-walled carbon nanotubes (MWCNTs) have been studied in this work. Circular dichroism (CD) studies show strong signals stemming from the chiral nematic structure. Notably, the introduction of the MWCNTs has a pronounced effect on the chiral structure of the as-prepared nanopaper. Our experimental results indicate the multiple weak molecular interactions existing between MWCNTs and NCC are responsible for the effective dispersion and stabilization of MWCNTs. Moreover it also confirms the resulting nanopaper has an increased conductivity of 4.2 S/m at 1.96 wt% MWCNTs. So the co-assembly of the nanocomposite herein opens a gateway for preparing functional materials combining the photonic properties of the NCC LCs matrix with other building blocks that can supply other advantageous functions.

  20. CERA: Clerkships Need National Curricula on Care Delivery, Awareness of Their NCC Gaps.

    Science.gov (United States)

    Cochella, Susan; Liaw, Winston; Binienda, Juliann; Hustedde, Carol

    2016-06-01

    The Society of Teachers of Family Medicine's (STFM) National Clerkship Curriculum (NCC) was created to standardize and improve teaching of a minimum core curriculum in family medicine clerkships, promoting the Triple Aim of better care and population health at lower cost. It includes competencies all clerkships should teach and tools to support clerkship directors (CDs). This 2014 CERA survey of clerkship directors is one of several needs assessments that guide STFM's NCC Editorial Board in targeting improvements and peer-review processes. CERA's 2014 survey of CDs was sent to all 137 CDs at US and Canadian allopathic medical schools. Primary aims included: (1) Identify curricular topics of greatest need, (2) Inventory the percent of family medicine clerkships teaching each NCC topic, and (3) Determine if longitudinal or blended clerkship have unique needs. This survey also assessed use of NCC to advocate for teaching resources and collaborate with colleagues at other institutions. Ninety-one percent of CDs completed the survey. Sixty-four percent reported their clerkship covers all of the NCC minimum core, but on detailed analysis, only 1% teach all topics. CDs need curricula on care delivery topics (cost-effective approach to acute care, role of family medicine in the health care system, quality/safety, and comorbid substance abuse). Single-question assessments overestimate the percentage of clerkships teaching all of the NCC minimum core. Clerkships need national curricula on care delivery topics and tools to help them find their curricular gaps.

  1. WNK-OSR1/SPAK-NCC signal cascade has circadian rhythm dependent on aldosterone.

    Science.gov (United States)

    Susa, Koichiro; Sohara, Eisei; Isobe, Kiyoshi; Chiga, Motoko; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2012-11-02

    Blood pressure and renal salt excretion show circadian rhythms. Recently, it has been clarified that clock genes regulate circadian rhythms of renal transporter expression in the kidney. Since we discovered the WNK-OSR1/SPAK-NaCl cotransporter (NCC) signal cascade, which is important for regulating salt balance and blood pressure, we have sought to determine whether NCC protein expression or phosphorylation shows diurnal rhythms in the mouse kidneys. Male C57BL/6J mice were sacrificed every 4h (at 20:00, 0:00, 4:00, 8:00, 12:00, and 16:00), and the expression and phosphorylation of WNK4, OSR1, SPAK, and NCC were determined by immunoblot. (Lights were turned on at 8:00, which was the start of the rest period, and turned off at 20:00, which was the start of the active period, since mice are nocturnal.) Although expression levels of each protein did not show diurnal rhythm, the phosphorylation levels of OSR1, SPAK, and NCC were increased around the start of the active period and decreased around the start of the rest period. Oral administration of eplerenone (10mg/day) attenuated the phosphorylation levels of these proteins and also diminished the diurnal rhythm of NCC phosphorylation. Thus, the activity of the WNK4-OSR1/SPAK-NCC cascade was shown to have a diurnal rhythm in the kidney that may be governed by aldosterone. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Novel NCC mutants and functional analysis in a new cohort of patients with Gitelman syndrome.

    Science.gov (United States)

    Glaudemans, Bob; Yntema, Helger G; San-Cristobal, Pedro; Schoots, Jeroen; Pfundt, Rolph; Kamsteeg, Erik-J; Bindels, René J; Knoers, Nine V A M; Hoenderop, Joost G; Hoefsloot, Lies H

    2012-03-01

    Gitelman syndrome (GS) is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis in conjunction with significant hypomagnesemia and hypocalciuria. The GS phenotype is caused by mutations in the solute carrier family 12, member 3 (SLC12A3) gene that encodes the thiazide-sensitive NaCl cotransporter (NCC). We analyzed DNA samples of 163 patients with a clinical suspicion of GS by direct sequencing of all 26 exons of the SLC12A3 gene. In total, 114 different mutations were identified, 31 of which have not been reported before. These novel variants include 3 deletions, 18 missense, 6 splice site and 4 nonsense mutations. We selected seven missense mutations to investigate their effect on NCC activity and plasma membrane localization by using the Xenopus laevis oocyte expression system. The Thr392Ile mutant did not display transport activity (probably class 2 mutation), while the Asn442Ser and Gln1030Arg NCC mutants showed decreased plasma membrane localization and consequently function, likely due to impaired trafficking (class 3 mutation). Even though the NaCl uptake was hampered for NCC mutants Glu121Asp, Pro751Leu, Ser475Cys and Tyr489His, the transporters reached the plasma membrane (class 4 mutation), suggesting an effect on NCC regulation or ion affinity. The present study shows the identification of 38 novel mutations in the SLC12A3 gene and provides insight into the mechanisms that regulate NCC.

  3. PTH modulation of NCC activity regulates TRPV5 Ca2+ reabsorption.

    Science.gov (United States)

    Hoover, Robert S; Tomilin, Viktor; Hanson, Lauren; Pochynyuk, Oleh; Ko, Benjamin

    2016-01-15

    Since parathyroid hormone (PTH) is known to increase transient receptor potential vanilloid (TRPV)5 activity and decrease Na(+)-Cl(-) cotransporter (NCC) activity, we hypothesized that decreased NCC-mediated Na(+) reabsorption contributes to the enhanced TRPV5 Ca(2+) reabsorption seen with PTH. To test this, we used mDCT15 cells expressing functional TRPV5 and ruthenium red-sensitive (45)Ca(2+) uptake. PTH increased (45)Ca(2+) uptake to 8.8 ± 0.7 nmol·mg(-1)·min(-1) (n = 4, P NCC activity from 75.4 ± 2.7 to 20.3 ± 1.3 nmol·mg(-1)·min(-1) (n = 4, P NCC is required for RasGRP1 knockdown to impact the PTH effect on TRPV5 activity. Knockdown of with no lysine kinase (WNK)4 resulted in an attenuation of the increase in PTH-mediated TRPV5 activity. TRPV5 activity increased by 36% compared with 45% in control (n = 4, P NCC activity contributes to the response to PTH, implying a role for hormonal modulation of NCC activity in distal Ca(2+) handling.

  4. Construction of nanometer cisplatin core-ferritin (NCC-F) and proteomic analysis of gastric cancer cell apoptosis induced with cisplatin released from the NCC-F.

    Science.gov (United States)

    Ji, Xue-Tao; Huang, Lin; Huang, He-Qing

    2012-06-18

    Both transmission electron microscopy (TEM) and fluorescence spectrometry were used to reveal the characteristics of both subunit disassociation and recombination in apo-pig pancreas ferritin (apoPPF) in an alkaline medium ranging reversibly from pH 7.0 to 13.0. The experimental results indicated that apoPPF could be completely disassociated into 24 free subunits at pH 13.0, and then these subunits could be quickly reassembled into the original apoPPF once the pH of the reactive medium was returned to pH7.0. This novel and simple method could be used to effectively construct a novel nanometer cisplatin core-PPF (NCC-PPF). The major characteristics of NCC-PPF were investigated using various analytical methods such as ultraviolet-spectrometry, circular dichroism spectrometry and TEM, which indicated that its molecular structure was still similar to that of the original apoPPF. Results from the inductively coupled plasma mass spectrometer (ICP-MS) method showed that 11.26 cisplatin (CDDP) molecules were successfully packaged within the NCC-PPF shell, indicating that each molecule of apoPPF had the ability to enwrap 11.26 CDDP molecules for constructing the NCC-PPF. Flow cytometry showed that NCC-PPF also had the ability to release CDDP for inducing the apoptosis of gastric cancer cells BGC823 (GCC), but this phenomenon could scarcely be observed using apoPPF. A differential proteomic technique using two-dimensional electrophoresis (2-DE) gels selected and identified the differential proteins from cell apoptosis in order to reveal the molecular pathway of GCC apoptosis by both NCC-PPF and free CDDP, giving 13 differential expression proteins. These differential proteins could be further classified into six groups, which were described as being involved in the regulation of apoptosis, RNA transcription, oxidative stress response, signal transduction, cell metabolism, and cytoskeleton changes. In addition, a real-time PCR method was used to prove the expression level of

  5. Increasing plasma [K+] by intravenous potassium infusion reduces NCC phosphorylation and drives kaliuresis and natriuresis.

    Science.gov (United States)

    Rengarajan, Srinivas; Lee, Donna H; Oh, Young Taek; Delpire, Eric; Youn, Jang H; McDonough, Alicia A

    2014-05-01

    Dietary potassium loading results in rapid kaliuresis, natriuresis, and diuresis associated with reduced phosphorylation (p) of the distal tubule Na(+)-Cl(-) cotransporter (NCC). Decreased NCC-p inhibits NCC-mediated Na(+) reabsorption and shifts Na(+) downstream for reabsorption by epithelial Na(+) channels (ENaC), which can drive K(+) secretion. Whether the signal is initiated by ingesting potassium or a rise in plasma K(+) concentration ([K(+)]) is not understood. We tested the hypothesis, in male rats, that an increase in plasma [K(+)] is sufficient to reduce NCC-p and drive kaliuresis. After an overnight fast, a single 3-h 2% potassium (2%K) containing meal increased plasma [K(+)] from 4.0 ± 0.1 to 5.2 ± 0.2 mM; increased urinary K(+), Na(+), and volume excretion; decreased NCC-p by 60%; and marginally reduced cortical Na(+)-K(+)-2Cl(-) cotransporter (NKCC) phosphorylation 25% (P = 0.055). When plasma [K(+)] was increased by tail vein infusion of KCl to 5.5 ± 0.1 mM over 3 h, significant kaliuresis and natriuresis ensued, NCC-p decreased by 60%, and STE20/SPS1-related proline alanine-rich kinase (SPAK) phosphorylation was marginally reduced 35% (P = 0.052). The following were unchanged at 3 h by either the potassium-rich meal or KCl infusion: Na(+)/H(+) exchanger 3 (NHE3), NHE3-p, NKCC, ENaC subunits, and renal outer medullary K(+) channel. In summary, raising plasma [K(+)] by intravenous infusion to a level equivalent to that observed after a single potassium-rich meal triggers renal kaliuretic and natriuretic responses, independent of K(+) ingestion, likely driven by decreased NCC-p and activity sufficient to shift sodium reabsorption downstream to where Na(+) reabsorption and flow drive K(+) secretion.

  6. WNK4 inhibits NCC protein expression through MAPK ERK1/2 signaling pathway.

    Science.gov (United States)

    Zhou, Bo; Wang, Dexuan; Feng, Xiuyan; Zhang, Yiqian; Wang, Yanhui; Zhuang, Jieqiu; Zhang, Xuemei; Chen, Guangping; Delpire, Eric; Gu, Dingying; Cai, Hui

    2012-03-01

    WNK [with no lysine (K)] kinase is a subfamily of serine/threonine kinases. Mutations in two members of this family (WNK1 and WNK4) cause pseudohypoaldosteronism type II featuring hypertension, hyperkalemia, and metabolic acidosis. WNK1 and WNK4 were shown to regulate sodium chloride cotransporter (NCC) activity through phosphorylating SPAK and OSR1. Previous studies including ours have also shown that WNK4 inhibits NCC function and its protein expression. A recent study reported that a phorbol ester inhibits NCC function via activation of extracellular signal-regulated kinase (ERK) 1/2 kinase. In the current study, we investigated whether WNK4 affects NCC via the MAPK ERK1/2 signaling pathway. We found that WNK4 increased ERK1/2 phosphorylation in a dose-dependent manner in mouse distal convoluted tubule (mDCT) cells, whereas WNK4 mutants with the PHA II mutations (E562K and R1185C) lost the ability to increase the ERK1/2 phosphorylation. Hypertonicity significantly increased ERK1/2 phosphorylation in mDCT cells. Knock-down of WNK4 expression by siRNA resulted in a decrease of ERK1/2 phosphorylation. We further showed that WNK4 knock-down significantly increases the cell surface and total NCC protein expressions and ERK1/2 knock-down also significantly increases cell surface and total NCC expression. These data suggest that WNK4 inhibits NCC through activating the MAPK ERK1/2 signaling pathway.

  7. The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate.

    Science.gov (United States)

    Mistry, Abinash C; Wynne, Brandi M; Yu, Ling; Tomilin, Viktor; Yue, Qiang; Zhou, Yiqun; Al-Khalili, Otor; Mallick, Rickta; Cai, Hui; Alli, Abdel A; Ko, Benjamin; Mattheyses, Alexa; Bao, Hui-Fang; Pochynyuk, Oleh; Theilig, Franziska; Eaton, Douglas C; Hoover, Robert S

    2016-10-01

    The thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC) are two of the most important determinants of salt balance and thus systemic blood pressure. Abnormalities in either result in profound changes in blood pressure. There is one segment of the nephron where these two sodium transporters are coexpressed, the second part of the distal convoluted tubule. This is a key part of the aldosterone-sensitive distal nephron, the final regulator of salt handling in the kidney. Aldosterone is the key hormonal regulator for both of these proteins. Despite these shared regulators and coexpression in a key nephron segment, associations between these proteins have not been investigated. After confirming apical localization of these proteins, we demonstrated the presence of functional transport proteins and native association by blue native PAGE. Extensive coimmunoprecipitation experiments demonstrated a consistent interaction of NCC with α- and γ-ENaC. Mammalian two-hybrid studies demonstrated direct binding of NCC to ENaC subunits. Fluorescence resonance energy transfer and immunogold EM studies confirmed that these transport proteins are within appropriate proximity for direct binding. Additionally, we demonstrate that there are functional consequences of this interaction, with inhibition of NCC affecting the function of ENaC. This novel finding of an association between ENaC and NCC could alter our understanding of salt transport in the distal tubule. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  8. Renal NCC is unchanged in the midpregnant rat and decreased in the late pregnant rat despite avid renal Na+ retention.

    Science.gov (United States)

    West, Crystal A; McDonough, Alicia A; Masilamani, Shyama M E; Verlander, Jill W; Baylis, Chris

    2015-07-01

    Pregnancy is characterized by plasma volume expansion due to Na(+) retention, driven by aldosterone. The aldosterone-responsive epithelial Na(+) channel is activated in the kidney in pregnancy. In the present study, we investigated the aldosterone-responsive Na(+)-Cl(-) cotransporter (NCC) in mid- and late pregnant rats compared with virgin rats. We determined the abundance of total NCC, phosphorylated NCC (pNCC; pT53, pS71 and pS89), phosphorylated STE20/SPS-1-related proline-alanine-rich protein kinase (pSPAK; pS373), and phosphorylated oxidative stress-related kinase (pOSR1; pS325) in the kidney cortex. We also measured mRNA expression of NCC and members of the SPAK/NCC regulatory kinase network, serum and glucocorticoid-regulated kinase (SGK)1, total with no lysine kinase (WNK)1, WNK3, and WNK4. Additionally, we performed immunohistochemistry for NCC kidneys from virgin and pregnant rats. Total NCC, pNCC, and pSPAK/OSR1 abundance were unchanged in midpregnant versus virgin rats. In late pregnant versus virgin rats, total NCC and pNCC were decreased; however, pSPAK/OSR1 was unchanged. We detected no differences in mRNA expression of NCC, SGK1, total WNK1, WNK3, and WNK4. By immunohistochemistry, NCC was mainly localized to the apical region in virgin rats, and density in the apical region was reduced in late pregnancy. Therefore, despite high circulating aldosterone levels in pregnancy, the aldosterone-responsive transporter NCC is not increased in total or activated (phosphorylated) abundance or in apical localization in midpregnant rats, and all are reduced in late pregnancy. This contrasts to the mineralocorticoid-mediated activation of the epithelial Na(+) channel, which we have previously reported. Why and how NCC escapes aldosterone activation in pregnancy is not clear but may relate to regional differences in aldosterone sensitivity the increased K(+) intake or other undefined mechanisms. Copyright © 2015 the American Physiological Society.

  9. Acute hypertension provokes acute trafficking of distal tubule Na-Cl cotransporter (NCC) to subapical cytoplasmic vesicles.

    Science.gov (United States)

    Lee, Donna H; Riquier, Anne D M; Yang, Li E; Leong, Patrick K K; Maunsbach, Arvid B; McDonough, Alicia A

    2009-04-01

    When blood pressure (BP) is elevated above baseline, a pressure natriuresis-diuresis response ensues, critical to volume and BP homeostasis. Distal convoluted tubule Na(+)-Cl(-) cotransporter (NCC) is regulated by trafficking between the apical plasma membrane (APM) and subapical cytoplasmic vesicles (SCV). We aimed to determine whether NCC trafficking contributes to pressure diuresis by decreasing APM NCC or compensates for increased volume flow to the DCT by increasing APM NCC. BP was raised 50 mmHg (high BP) in rats by arterial constriction for 5 or 20-30 min, provoking a 10-fold diuresis at both times. Kidneys were excised, and NCC subcellular distribution was analyzed by 1) sorbitol density gradient fractionation and immunoblotting and 2) immunoelectron microscopy (immuno-EM). NCC distribution did not change after 5-min high BP. After 20-30 min of high BP, 20% of NCC redistributed from low-density, APM-enriched fractions to higher density, endosome-enriched fractions, and, by quantitative immuno-EM, pool size of APM NCC decreased 14% and SCV pool size increased. Because of the time lag of the response, we tested the hypothesis that internalization of NCC was secondary to the decrease in ANG II that accompanies high BP. Clamping ANG II at a nonpressor level by coinfusion of captopril (12 microg/min) and ANG II (20 ng.kg(-1).min(-1)) during 30-min high BP reduced diuresis to eightfold and prevented redistribution of NCC from APM- to SCV-enriched fractions. We conclude that DCT NCC may participate in pressure natriuresis-diuresis by retraction out of apical plasma membranes and that the retraction is, at least in part, driven by the fall in ANG II that accompanies acute hypertension.

  10. Model of the containment building of Almaraz NPP and the system of recombiners PARs, with the GOTHIC code, for the study of the diffusion of combustible gases; Modelo del edificio de contencion de C.N. Almaraz y del sistema de recombinadores PARs, con el codigo GOTHIC, para el estudio de la difusion de gases combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gonzalez, M.; Huelamo, E.; Mazrtinez, M.; Perez, J. R.

    2014-07-01

    This paper presents the analysis of distribution of gases within the containment building carried out a simulation model with the code Thermo hydraulic GOTHIC, which has been evaluated based on passive autocatalytic recombiners gas control system. The model considers scenarios of severe accident with specific conditions that produce the most hydrogen generation rates. Intended to verify the effectiveness of the control system of gas expected to be installed in the Almaraz Nuclear power plant so that the number and location of recombiners equipment meets its function of preventing the formation of explosive atmospheres which impairs the integrity of the containment, reducing and limiting the concentration of combustible gases during the postulated accident. (Author)

  11. Albuminuria enhances NHE3 and NCC via stimulation of mitochondrial oxidative stress/angiotensin II axis.

    Science.gov (United States)

    Jia, Zhanjun; Zhuang, Yibo; Hu, Caiyu; Zhang, Xintong; Ding, Guixia; Zhang, Yue; Rohatgi, Rajeev; Hua, Hu; Huang, Songming; He, John Ci-Jiang; Zhang, Aihua

    2016-07-26

    Imbalance of salt and water is a frequent and challenging complication of kidney disease, whose pathogenic mechanisms remain elusive. Employing an albumin overload mouse model, we discovered that albuminuria enhanced the expression of NHE3 and NCC but not other transporters in murine kidney in line with the stimulation of angiotensinogen (AGT)/angiotensin converting enzyme (ACE)/angiotensin (Ang) II cascade. In primary cultures of renal tubular cells, albumin directly stimulated AGT/ACE/Ang II and upregulated NHE3 and NCC expression. Blocking Ang II production with an ACE inhibitor normalized the upregulation of NHE3 and NCC in cells. Interestingly, albumin overload significantly reduced mitochondrial superoxide dismutase (SOD2), and administration of a SOD2 mimic (MnTBAP) normalized the expression of NHE3, NCC, and the components of AGT/ACE pathway affected by albuminuria, indicating a key role of mitochondria-derived oxidative stress in modulating renin-angiotensin system (RAS) and renal sodium transporters. In addition, the functional data showing the reduced urinary excretion of Na and Cl and enhanced response to specific NCC inhibitor further supported the regulatory results of sodium transporters following albumin overload. More importantly, the upregulation of NHE3 and NCC and activation of ACE/Ang II signaling pathway were also observed in albuminuric patient kidneys, suggesting that our animal model accurately replicates the human condition. Taken together, these novel findings demonstrated that albuminuria is of importance in resetting renal salt handling via mitochondrial oxidative stress-initiated stimulation of ACE/Ang II cascade. This may also offer novel, effective therapeutic targets for dealing with salt and water imbalance in proteinuric renal diseases.

  12. NCC Simulation Model: Simulating the operations of the network control center, phase 2

    Science.gov (United States)

    Benjamin, Norman M.; Paul, Arthur S.; Gill, Tepper L.

    1992-01-01

    The simulation of the network control center (NCC) is in the second phase of development. This phase seeks to further develop the work performed in phase one. Phase one concentrated on the computer systems and interconnecting network. The focus of phase two will be the implementation of the network message dialogues and the resources controlled by the NCC. These resources are requested, initiated, monitored and analyzed via network messages. In the NCC network messages are presented in the form of packets that are routed across the network. These packets are generated, encoded, decoded and processed by the network host processors that generate and service the message traffic on the network that connects these hosts. As a result, the message traffic is used to characterize the work done by the NCC and the connected network. Phase one of the model development represented the NCC as a network of bi-directional single server queues and message generating sources. The generators represented the external segment processors. The served based queues represented the host processors. The NCC model consists of the internal and external processors which generate message traffic on the network that links these hosts. To fully realize the objective of phase two it is necessary to identify and model the processes in each internal processor. These processes live in the operating system of the internal host computers and handle tasks such as high speed message exchanging, ISN and NFE interface, event monitoring, network monitoring, and message logging. Inter process communication is achieved through the operating system facilities. The overall performance of the host is determined by its ability to service messages generated by both internal and external processors.

  13. Beneficial effect of Lactococcus lactis NCC 2287 in a murine model of eosinophilic esophagitis.

    Science.gov (United States)

    Holvoet, S; Doucet-Ladevèze, R; Perrot, M; Barretto, C; Nutten, S; Blanchard, C

    2016-12-01

    Eosinophilic esophagitis (EoE) is a severe inflammatory disease of the esophagus which is characterized histologically by an eosinophilic infiltration into the esophageal tissue. The efficacy of probiotics in the context of atopic diseases has been well investigated but, to date, there has been no study which has evaluated probiotic effects on EoE inflammation. This study sought to identify a probiotic which improves esophageal inflammation in experimental EoE. Two candidate probiotics, Lactococcus lactis NCC 2287 and Bifidobacterium lactis NCC 2818, were tested in a murine model of EoE elicited by epicutaneous sensitization with Aspergillus fumigatus protein extract. Administration of bacterial strains in drinking water was used, respectively, as a preventive or treatment measure, or continuously throughout the study. Inflammatory parameters were assessed in the esophagus, skin, and lungs after allergen challenge. In this EoE model, supplementation with L. lactis NCC 2287 significantly decreased esophageal and bronchoalveolar eosinophilia but only when given as a therapeutic treatment. No significant effect on eosinophilia was observed when NCC 2287 was given as a preventive or a continuous intervention. NCC 2287 supplementation had no significant effect on immunoglobulin levels, skin symptom scores, or on transepidermal water loss. Supplementation with another probiotic, B. lactis NCC 2818, had no significant effect on esophageal eosinophilia. We identified a L. lactis strain, able to attenuate esophageal eosinophilic inflammation in a preclinical model of EoE. This effect is strain specific and depends on the timing and duration of bacterial supplementation. Confirmation of these observations in human clinical trials is warranted. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Constitutively Active SPAK Causes Hyperkalemia by Activating NCC and Remodeling Distal Tubules.

    Science.gov (United States)

    Grimm, P Richard; Coleman, Richard; Delpire, Eric; Welling, Paul A

    2017-09-01

    Aberrant activation of with no lysine (WNK) kinases causes familial hyperkalemic hypertension (FHHt). Thiazide diuretics treat the disease, fostering the view that hyperactivation of the thiazide-sensitive sodium-chloride cotransporter (NCC) in the distal convoluted tubule (DCT) is solely responsible. However, aberrant signaling in the aldosterone-sensitive distal nephron (ASDN) and inhibition of the potassium-excretory renal outer medullary potassium (ROMK) channel have also been implicated. To test these ideas, we introduced kinase-activating mutations after Lox-P sites in the mouse Stk39 gene, which encodes the terminal kinase in the WNK signaling pathway, Ste20-related proline-alanine-rich kinase (SPAK). Renal expression of the constitutively active (CA)-SPAK mutant was specifically targeted to the early DCT using a DCT-driven Cre recombinase. CA-SPAK mice displayed thiazide-treatable hypertension and hyperkalemia, concurrent with NCC hyperphosphorylation. However, thiazide-mediated inhibition of NCC and consequent restoration of sodium excretion did not immediately restore urinary potassium excretion in CA-SPAK mice. Notably, CA-SPAK mice exhibited ASDN remodeling, involving a reduction in connecting tubule mass and attenuation of epithelial sodium channel (ENaC) and ROMK expression and apical localization. Blocking hyperactive NCC in the DCT gradually restored ASDN structure and ENaC and ROMK expression, concurrent with the restoration of urinary potassium excretion. These findings verify that NCC hyperactivity underlies FHHt but also reveal that NCC-dependent changes in the driving force for potassium secretion are not sufficient to explain hyperkalemia. Instead, a DCT-ASDN coupling process controls potassium balance in health and becomes aberrantly activated in FHHt. Copyright © 2017 by the American Society of Nephrology.

  15. Aldosterone does not require angiotensin II to activate NCC through a WNK4-SPAK-dependent pathway

    NARCIS (Netherlands)

    N. van der Lubbe (Nils); C.H. Lim (Christina); M.E. Meima (Marcel); R. van Veghel (Richard); L.L. Rosenbaek (Lena Lindtoft); K. Mutig (Kerim); A.H.J. Danser (Jan); R.A. Fenton (Robert); R. Zietse (Robert); E.J. Hoorn (Ewout)

    2012-01-01

    textabstractWe and others have recently shown that angiotensin II can activate the sodium chloride cotransporter (NCC) through a WNK4-SPAK-dependent pathway. Because WNK4 was previously shown to be a negative regulator of NCC, it has been postulated that angiotensin II converts WNK4 to a positive re

  16. Aldosterone does not require angiotensin II to activate NCC through a WNK4-SPAK-dependent pathway

    NARCIS (Netherlands)

    N. van der Lubbe (Nils); C.H. Lim (Christina); M.E. Meima (Marcel); R. van Veghel (Richard); L.L. Rosenbaek (Lena Lindtoft); K. Mutig (Kerim); A.H.J. Danser (Jan); R.A. Fenton (Robert); R. Zietse (Bob); E.J. Hoorn (Ewout)

    2012-01-01

    textabstractWe and others have recently shown that angiotensin II can activate the sodium chloride cotransporter (NCC) through a WNK4-SPAK-dependent pathway. Because WNK4 was previously shown to be a negative regulator of NCC, it has been postulated that angiotensin II converts WNK4 to a positive

  17. Double knockout of carbonic anhydrase II (CAII) and Na(+)-Cl(-) cotransporter (NCC) causes salt wasting and volume depletion.

    Science.gov (United States)

    Xu, Jie; Barone, Sharon; Brooks, Mary-Beth; Soleimani, Manoocher

    2013-01-01

    The thiazide-sensitive Na(+)-Cl(-) cotransporter NCC and the Cl(-)/HCO3(-)exchanger pendrin are expressed on apical membranes of distal cortical nephron segments and mediate salt absorption, with pendrin working in tandem with the epithelial Na(+) channel (ENaC) and the Na(+)-dependent chloride/bicarbonate exchanger (NDCBE), whereas NCC is working by itself. A recent study showed that NCC and pendrin compensate for loss of each other under basal conditions, therefore masking the role that each plays in salt reabsorption. Carbonic anhydrase II (CAII, CA2 or CAR2) plays an important role in acid-base transport and salt reabsorption in the proximal convoluted tubule and acid-base transport in the collecting duct. Animals with CAII deletion show remodeling of intercalated cells along with the downregulation of pendrin. NCC KO mice on the other hand show significant upregulation of pendrin and ENaC. Neither model shows any significant salt wasting under baseline conditions. We hypothesized that the up-regulation of pendrin is essential for the prevention of salt wasting in NCC KO mice. To test this hypothesis, we generated NCC/CAII double KO (dKO) mice by crossing mice with single deletion of NCC and CAII. The NCC/CAII dKO mice displayed significant downregulation of pendrin, along with polyuria and salt wasting. As a result, the dKO mice developed volume depletion, which was associated with the inability to concentrate urine. We conclude that the upregulation of pendrin is essential for the prevention of salt and water wasting in NCC deficient animals and its downregulation or inactivation will result in salt wasting, impaired water conservation and volume depletion in the setting of NCC inactivation or inhibition. © 2014 S. Karger AG, Basel.

  18. Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill

    Science.gov (United States)

    Breves, Jason P.; Serizier, Sandy B.; Goffin, Vincent; McCormick, Stephen D.; Karlstrom, Rolf O.

    2013-01-01

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na+/Cl− cotransporter (ncc; slc12a10.2), Na+/H+ exchanger (nhe3b; slc9a3.2), and epithelial Ca2+ channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl− uptake in zebrafish for the first time.

  19. Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill.

    Science.gov (United States)

    Breves, Jason P; Serizier, Sandy B; Goffin, Vincent; McCormick, Stephen D; Karlstrom, Rolf O

    2013-04-30

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na(+)/Cl(-) cotransporter (ncc; slc12a10.2), Na(+)/H(+) exchanger (nhe3b; slc9a3.2), and epithelial Ca(2+) channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl(-) uptake in zebrafish for the first time. Copyright © 2013. Published by Elsevier Ireland Ltd.

  20. FUNCTIONOMICS OF NCC MUTATIONS IN GITELMAN SYNDROME USING A NOVEL MAMMALIAN CELL-BASED ACTIVITY ASSAY.

    NARCIS (Netherlands)

    Valdez-Flores, M.A.; Vargas-Poussou, R.; Verkaart, S.; Tutakhel, O.A.Z.; Valdez-Ortiz, A.; Blanchard, A.; Treard, C.; Hoenderop, J.G.J.; Bindels, R.J.M.; Jelen, S.

    2016-01-01

    Gitelman syndrome (GS) is an autosomal recessive salt-wasting tubular disorder resulting from loss-of-function mutations in the thiazide-sensitive NaCl cotransporter (NCC). Functional analysis of these mutations has been limited to the use of Xenopus laevis oocytes. The aim of the present study was,

  1. Computational Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Mizobuchi, Y; Poinsot, T J; Smith, P J; Warnatz, J

    2004-08-26

    Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surface and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.

  2. Criticality calculations of a generic fuel container for fuel assemblies PWR, by means of the code MCNP; Calculos de criticidad de un contenedor de combustible generico para ensambles combustibles PWR, mediante el codigo MCNP

    Energy Technology Data Exchange (ETDEWEB)

    Vargas E, S.; Esquivel E, J.; Ramirez S, J. R., E-mail: samuel.vargas@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    The purpose of the concept of burned consideration (Burn-up credit) is determining the capacity of the calculation codes, as well as of the nuclear data associates to predict the isotopic composition and the corresponding neutrons effective multiplication factor in a generic container of spent fuel during some time of relevant storage. The present work has as objective determining this capacity of the calculation code MCNP in the prediction of the neutrons effective multiplication factor for a fuel assemblies arrangement type PWR inside a container of generic storage. The calculations are divided in two parts, the first, in the decay calculations with specified nuclide concentrations by the reference for a pressure water reactor (PWR) with enriched fuel to 4.5% and a discharge burned of 50 GW d/Mtu. The second, in criticality calculations with isotopic compositions dependent of the time for actinides and important fission products, taking 30 time steps, for two actinide groups and fission products. (Author)

  3. Preparation and Characterization of NCC/Modified Nano-silica/PVA Blend Membrane%NCC/改性纳米SiO2/PVA共混膜的制备及表征

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Nanocrystalline cellulose(NCC)/modified nano-silica(SiO2)/polyvinyl alcohol(PVA) blend membrane was prepared by blending method. The results of fourier transform infrared(FTIR) spectroscopy analysis showed that blending mode of NCC/modified nano-SiO2/PVA blend membrane was simple physical blending of hydrogen bonding interactions. The results of mechanical performance analysis showed that tensile strength of NCC/modified nano-SiO2/PVA blend membrane was higher than that of PVA membrane, the average tensile strength of NCC/modified nano-SiO2/PVA blend membrane was 128.41MPa. The results of thermal performance analysis showed that the thermal stability of NCC/modified nano-SiO2/PVA blend membrane was better than that of PVA membrane, the maximum thermal weight loss temperature of NCC/modified nano-SiO2/PVA blend membrane was 238 ℃.The results of scanning electron microscopy(SEM) analysis showed that surface morphology and cross-section morphology of NCC/modified nano-SiO2/PVA blend membrane was more structured.%  采用共混法制备了纳米纤维素(NCC)/改性纳米二氧化硅(SiO2)/聚乙烯醇(PVA)共混膜。傅里叶变换红外(FTIR)光谱分析结果表明NCC/改性纳米SiO2/PVA共混膜的共混模式为存在氢键作用力的简单物理共混。力学性能分析结果表明NCC/改性纳米SiO2/PVA共混膜较PVA膜具有较高的拉伸强度,其拉伸强度平均值为128.41 MPa。热学性能分析结果表明NCC/改性纳米SiO2/PVA共混膜较PVA膜具有较好的热稳定性,其最大热失重温度为238℃。扫描电子显微镜(SEM)图分析结果表明NCC/改性纳米SiO2/PVA共混膜样品的表面和断面形貌较规整。

  4. Double knockout of pendrin and Na-Cl cotransporter (NCC) causes severe salt wasting, volume depletion, and renal failure.

    Science.gov (United States)

    Soleimani, Manoocher; Barone, Sharon; Xu, Jie; Shull, Gary E; Siddiqui, Faraz; Zahedi, Kamyar; Amlal, Hassane

    2012-08-14

    The Na-Cl cotransporter (NCC), which is the target of inhibition by thiazides, is located in close proximity to the chloride-absorbing transporter pendrin in the kidney distal nephron. Single deletion of pendrin or NCC does not cause salt wasting or excessive diuresis under basal conditions, raising the possibility that these transporters are predominantly active during salt depletion or in response to excess aldosterone. We hypothesized that pendrin and NCC compensate for loss of function of the other under basal conditions, thereby masking the role that each plays in salt absorption. To test our hypothesis, we generated pendrin/NCC double knockout (KO) mice by crossing pendrin KO mice with NCC KO mice. Pendrin/NCC double KO mice displayed severe salt wasting and sharp increase in urine output under basal conditions. As a result, animals developed profound volume depletion, renal failure, and metabolic alkalosis without hypokalemia, which were all corrected with salt replacement. We propose that the combined inhibition of pendrin and NCC can provide a strong diuretic regimen without causing hypokalemia for patients with fluid overload, including patients with congestive heart failure, nephrotic syndrome, diuretic resistance, or generalized edema.

  5. Circadian exosomal expression of renal thiazide-sensitive NaCl cotransporter (NCC) and prostasin in healthy individuals.

    Science.gov (United States)

    Castagna, Annalisa; Pizzolo, Francesca; Chiecchi, Laura; Morandini, Francesca; Channavajjhala, Sarath Kiran; Guarini, Patrizia; Salvagno, Gianluca; Olivieri, Oliviero

    2015-06-01

    A circadian timing system is involved in the maintenance of fluid and electrolyte balance and blood pressure control. Aldosterone and vasopressin modulate ion transporters and channels crucial in sodium (Na) and water reabsorption such as the epithelium Na channel and the renal thiazide-sensitive NaCl cotransporter (NCC). We analyzed in urinary exosomes the intraday variations of NCC and prostasin expression and the association with electrolytes and water balance parameters. Blood and urine samples were collected at five time points during the day from five healthy subjects. Blood renin, aldosterone, cortisol, ACTH, and plasmatic and urinary Na, potassium, creatinine, adiuretin (ADH), NCC, and prostasin were evaluated. ACTH and cortisol showed a circadian pattern, similarly to aldosterone, while exosomal NCC and prostasin pattern were similar to urinary ADH, decreased in the morning and subsequently increased in the afternoon and evening. In urinary exosomes, NCC and prostasin had a diurnal pattern parallel to ADH and aquaporin 2, confirming that, in healthy subjects, both prostasin and NCC relate to water balance. These results provide suggestions for a possible chronotherapeutic approach in patients treated with thiazides, diuretic drugs acting as specific inhibitors of NCC-mediated Na reabsorption. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Verification of Serpent code for the fuel analysis of a PBMR; Verificacion del codigo SERPENT para el analisis de combustible para un PBMR

    Energy Technology Data Exchange (ETDEWEB)

    Bastida O, G. E.; Francois L, J. L., E-mail: gbo729@yahoo.com.mx [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

    2015-09-15

    In this paper the models and simulations with the Monte Carlo code Serpent are presented, as well as the obtained results of the different analyzed cases in order to verify the suitability or reliability of the use of this code to ensure favorable results in the realization of a neutronic analysis of fuel for a Pebble Bed Modular Reactor (PBMR). Comparisons were made with the results reported in a report by the OECD/Nea relative to a high temperature reactor of spheres bed with plutonium reactor grade as fuel. The results show that the use of Serpent is appropriate, as these results are comparable with those reported in the report. (Author)

  7. Inactivation of the Na-Cl co-transporter (NCC) gene is associated with high BMD through both renal and bone mechanisms: analysis of patients with Gitelman syndrome and Ncc null mice.

    Science.gov (United States)

    Nicolet-Barousse, Laurence; Blanchard, Anne; Roux, Christian; Pietri, Laurence; Bloch-Faure, May; Kolta, Sami; Chappard, Christine; Geoffroy, Valérie; Morieux, Caroline; Jeunemaitre, Xavier; Shull, Gary E; Meneton, Pierre; Paillard, Michel; Houillier, Pascal; De Vernejoul, Marie-Christine

    2005-05-01

    Chronic thiazide treatment is associated with high BMD. We report that patients and mice with null mutations in the thiazide-sensitive NaCl cotransporter (NCC) have higher renal tubular Ca reabsorption, higher BMD, and lower bone remodeling than controls, as well as abnormalities in Ca metabolism, mainly caused by Mg depletion. Chronic thiazide treatment decreases urinary Ca excretion (UVCa) and increases BMD. To understand the underlying mechanisms, Ca and bone metabolism were studied in two models of genetic inactivation of the thiazide-sensitive NaCl cotransporter (NCC): patients with Gitelman syndrome (GS) and Ncc knockout (Ncc(-/-)) mice. Ca metabolism was analyzed in GS patients and Ncc(-/-) mice under conditions of low dietary Ca. BMD was measured by DXA in patients and mice, and bone histomorphometry was analyzed in mice. GS patients had low plasma Mg. They exhibited reduced UVCa, but similar serum Ca and GFR as control subjects, suggesting increased renal Ca reabsorption. Blood PTH was lower despite lower serum ionized Ca, and Mg repletion almost corrected both relative hypoparathyroidism and low UVCa. BMD was significantly increased in GS patients at both lumbar (+7%) and femoral (+16%) sites, and osteocalcin was reduced. In Ncc(-/-) mice, serum Ca and GFR were unchanged, but UVCa was reduced and PTH was elevated; Mg repletion largely corrected both abnormalities. Trabecular and cortical BMD were higher than in Ncc(+/+) mice (+4% and +5%, respectively), and despite elevated PTH, were associated with higher cortical thickness and lower endosteal osteoclastic surface. Higher BMD is observed in GS patients and Ncc(-/-) mice. Relative hypoparathyroidism (human) and bone resistance to PTH (mice), mainly caused by Mg depletion, can explain the low bone remodeling and normal/low serum Ca despite increased renal Ca reabsorption.

  8. Thermomechanical analysis of fuel rods during transitory events using the RAMONA and FETMA codes; Analisis termomecanico de barras combustibles durante eventos transitorios usando los codigos RAMONA y FETMA

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez L, H. [ININ, Departamento de Sistemas Nucleares, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)], e-mail: hector.hernandez@inin.gob.mx

    2009-10-15

    In National Institute of Nuclear Research, the fuel management system (FMS) has been used by long time to simulate the BWR operation in stationary state, as well as during a transitory event. To evaluate the thermomechanical behavior of a fuel element was created and interface between the FMS codes and the fuel element thermo mechanical analysis (FETMA) code properly developed and implemented. In this work, the results of thermomechanical behavior of fuel rods that compose the hot channel during the simulation of a transitory event of a BWR are shown. The transitory events considered in this work are a load rejection and failure in controller of feed water, which are events more important that can to occur in a BWR. The results show that during the developed conditions by both transitory events some failure is not presented in fuel rods. Also, that the transitory event of load rejection is more claimant in security terms that of controller failure of feed water. (Author)

  9. Manifold methods for methane combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yang, B.; Pope, S.B. [Cornell Univ., Ithaca, NY (United States)

    1995-10-01

    Great progresses have been made in combustion research, especially, the computation of laminar flames and the probability density function (PDF) method in turbulent combustion. For one-dimensional laminar flames, by considering the transport mechanism, the detailed chemical kinetic mechanism and the interactions between these two basic processes, today it is a routine matter to calculate flame velocities, extinction, ignition, temperature, and species distributions from the governing equations. Results are in good agreement with those obtained for experiments. However, for turbulent combustion, because of the complexities of turbulent flow, chemical reactions, and the interaction between them, in the foreseeable future, it is impossible to calculate the combustion flow field by directly integrating the basic governing equations. So averaging and modeling are necessary in turbulent combustion studies. Averaging, on one hand, simplifies turbulent combustion calculations, on the other hand, it introduces the infamous closure problems, especially the closure problem with chemical reaction terms. Since in PDF calculations of turbulent combustion, the averages of the chemical reaction terms can be calculated, PDF methods overcome the closure problem with the reaction terms. It has been shown that the PDF method is a most promising method to calculate turbulent combustion. PDF methods have been successfully employed to calculate laboratory turbulent flames: they can predict phenomena such as super equilibrium radical levels, and local extinction. Because of these advantages, PDF methods are becoming used increasingly in industry combustor codes.

  10. PVA/NCC-金胺O/PVA复合荧光膜的制备和表征%Preparation and characterization of PVA/NCC-auramine O/PVA composite fluorescent membrane

    Institute of Scientific and Technical Information of China (English)

    刘志明; 杨少丽

    2013-01-01

    以金胺O为荧光染色剂,纳米纤维素(NCC)为增强相,氢键为驱动力,层层自组装PVA/NCC-金胺O/PVA复合荧光膜.NCC的性能表征结果为NCC为纤维素Ⅰ型,结晶度为65.55%,平均尺寸为477.2nm,呈棒状.PVA/NCC-金胺O/PVA复合荧光膜的性能表征结果为PVA/NCC-金胺O/PVA复合荧光膜具有优良的拉伸强度,其拉伸强度较纯PVA膜相比,横向拉伸增加了66.8%,纵向拉伸增加了230.9%.PVA/NCC-金胺O/PVA复合荧光膜具有良好的荧光效应,且PVA/NCC-金胺O/PVA复合荧光膜的荧光发射波长为520nm.

  11. Acute inhibition of NCC does not activate distal electrogenic Na+ reabsorption or kaliuresis.

    Science.gov (United States)

    Hunter, Robert W; Craigie, Eilidh; Homer, Natalie Z M; Mullins, John J; Bailey, Matthew A

    2014-02-15

    Na(+) reabsorption from the distal renal tubule involves electroneutral and electrogenic pathways, with the latter promoting K(+) excretion. The relative activities of these two pathways are tightly controlled, participating in the minute-to-minute regulation of systemic K(+) balance. The pathways are interdependent: the activity of the NaCl cotransporter (NCC) in the distal convoluted tubule influences the activity of the epithelial Na(+) channel (ENaC) downstream. This effect might be mediated by changes in distal Na(+) delivery per se or by molecular and structural adaptations in the connecting tubule and collecting ducts. We hypothesized that acute inhibition of NCC activity would cause an immediate increase in Na(+) flux through ENaC, with a concomitant increase in renal K(+) excretion. We tested this using renal clearance methodology in anesthetized mice, by the administration of hydrochlorothiazide (HCTZ) and/or benzamil (BZM) to exert specific blockade of NCC and ENaC, respectively. Bolus HCTZ elicited a natriuresis that was sustained for up to 110 min; urinary K(+) excretion was not affected. Furthermore, the magnitude of the natriuresis was no greater during concomitant BZM administration. This suggests that ENaC-mediated Na(+) reabsorption was not normally limited by Na(+) delivery, accounting for the absence of thiazide-induced kaliuresis. After dietary Na(+) restriction, HCTZ elicited a kaliuresis, but the natiuretic effect of HCTZ was not enhanced by BZM. Our findings support a model in which inhibition of NCC activity does not increase Na(+) reabsorption through ENaC solely by increasing distal Na(+) delivery but rather by inducing a molecular and structural adaptation in downstream nephron segments.

  12. Aldosterone does not require angiotensin II to activate NCC through a WNK4-SPAK-dependent pathway.

    Science.gov (United States)

    van der Lubbe, Nils; Lim, Christina H; Meima, Marcel E; van Veghel, Richard; Rosenbaek, Lena Lindtoft; Mutig, Kerim; Danser, Alexander H J; Fenton, Robert A; Zietse, Robert; Hoorn, Ewout J

    2012-06-01

    We and others have recently shown that angiotensin II can activate the sodium chloride cotransporter (NCC) through a WNK4-SPAK-dependent pathway. Because WNK4 was previously shown to be a negative regulator of NCC, it has been postulated that angiotensin II converts WNK4 to a positive regulator. Here, we ask whether aldosterone requires angiotensin II to activate NCC and if their effects are additive. To do so, we infused vehicle or aldosterone in adrenalectomized rats that also received the angiotensin receptor blocker losartan. In the presence of losartan, aldosterone was still capable of increasing total and phosphorylated NCC twofold to threefold. The kinases WNK4 and SPAK also increased with aldosterone and losartan. A dose-dependent relationship between aldosterone and NCC, SPAK, and WNK4 was identified, suggesting that these are aldosterone-sensitive proteins. As more functional evidence of increased NCC activity, we showed that rats receiving aldosterone and losartan had a significantly greater natriuretic response to hydrochlorothiazide than rats receiving losartan only. To study whether angiotensin II could have an additive effect, rats receiving aldosterone with losartan were compared with rats receiving aldosterone only. Rats receiving aldosterone only retained more sodium and had twofold to fourfold increase in phosphorylated NCC. Together, our results demonstrate that aldosterone does not require angiotensin II to activate NCC and that WNK4 appears to act as a positive regulator in this pathway. The additive effect of angiotensin II may favor electroneutral sodium reabsorption during hypovolemia and may contribute to hypertension in diseases with an activated renin-angiotensin-aldosterone system.

  13. Assessment of Literature Related to Combustion Appliance Venting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  14. The Application of ARGO Data to the Global Ocean Data Assimilation Operational System of NCC

    Institute of Scientific and Technical Information of China (English)

    LIU Yimin; ZHANG Renhe; YIN Yonghong; NIU Tao

    2005-01-01

    In this paper, we have preliminarily studied the application of ARGO (Array for Real-time Geostrophic Oceanography) data to the Global Ocean Data Assimilation System of National Climate Center of China (NCC-GODAS), which mainly contains 4 sub-systems such as data preprocessing, real-time wind stress calculating, variational analysis and interpolating, and ocean dynamic model. For the sake of using ARGO data, the relevant adjustment and improvement have been made at the corresponding aspects in the subsystems.Using the observation data from 1981 to 2003 including the ARGO data of 2001 to July. 2003, we have performed a series of numerical experiments on this system. Comparing with the corresponding results of NCEP, It is illustrated that using ARGO data can improve the results of NCC-GODAS in the region of the Middle Pacific, for instance SST, SSTA (SST anomalies), Nino index, sea sub-surface temperature,etc. Furthermore, it is obtained that NCC-GODAS benefits from ARGO data in the other regions such as Atlantic Ocean, Indian Ocean, and extratropical Pacific Ocean much more than in the tropical Pacific.

  15. 2014 KLCSG-NCC Korea Practice Guidelines for the management of hepatocellular carcinoma: HCC diagnostic algorithm.

    Science.gov (United States)

    Lee, Jeong Min; Park, Joong-Won; Choi, Byung Ihn

    2014-01-01

    Hepatocellular carcinoma (HCC) is the fifth most commonly occurring cancer in Korea and typically has a poor prognosis with a 5-year survival rate of only 28.6%. Therefore, it is of paramount importance to achieve the earliest possible diagnosis of HCC and to recommend the most up-to-date optimal treatment strategy in order to increase the survival rate of patients who develop this disease. After the establishment of the Korean Liver Cancer Study Group (KLCSG) and the National Cancer Center (NCC), Korea jointly produced for the first time the Clinical Practice Guidelines for HCC in 2003, revised them in 2009, and published the newest revision of the guidelines in 2014, including changes in the diagnostic criteria of HCC and incorporating the most recent medical advances over the past 5 years. In this review, we will address the noninvasive diagnostic criteria and diagnostic algorithm of HCC included in the newly established KLCSG-NCC guidelines in 2014, and review the differences in the criteria for a diagnosis of HCC between the KLCSG-NCC guidelines and the most recent imaging guidelines endorsed by the European Organisation for Research and Treatment of Cancer (EORTC), the Liver Imaging Reporting and Data System (LI-RADS), the Organ Procurement and Transplantation Network (OPTN) system, the Asian Pacific Association for the Study of the Liver (APASL) and the Japan Society of Hepatology (JSH).

  16. Chromatin Dynamics During DNA Replication and Uncharacterized Replication Factors determined by Nascent Chromatin Capture (NCC) Proteomics

    Science.gov (United States)

    Alabert, Constance; Bukowski-Wills, Jimi-Carlo; Lee, Sung-Bau; Kustatscher, Georg; Nakamura, Kyosuke; de Lima Alves, Flavia; Menard, Patrice; Mejlvang, Jakob; Rappsilber, Juri; Groth, Anja

    2014-01-01

    SUMMARY To maintain genome function and stability, DNA sequence and its organization into chromatin must be duplicated during cell division. Understanding how entire chromosomes are copied remains a major challenge. Here, we use Nascent Chromatin Capture (NCC) to profile chromatin proteome dynamics during replication in human cells. NCC relies on biotin-dUTP labelling of replicating DNA, affinity-purification and quantitative proteomics. Comparing nascent chromatin with mature post-replicative chromatin, we provide association dynamics for 3995 proteins. The replication machinery and 485 chromatin factors like CAF-1, DNMT1, SUV39h1 are enriched in nascent chromatin, whereas 170 factors including histone H1, DNMT3, MBD1-3 and PRC1 show delayed association. This correlates with H4K5K12diAc removal and H3K9me1 accumulation, while H3K27me3 and H3K9me3 remain unchanged. Finally, we combine NCC enrichment with experimentally derived chromatin probabilities to predict a function in nascent chromatin for 93 uncharacterized proteins and identify FAM111A as a replication factor required for PCNA loading. Together, this provides an extensive resource to understand genome and epigenome maintenance. PMID:24561620

  17. THE LEGAL STATUS OF PROFESSIONALS IN THE CONTEXT OF CHANGES BROUGHT BY THE NEW CIVIL CODE

    Directory of Open Access Journals (Sweden)

    OANA-CARMEN RĂVAŞ

    2014-12-01

    Full Text Available Adoption of the New Civil Code (NCC meant a "turning point" for the radical concept of the subjects participating in legal relations which, according to the Commercial Code (now repealed almost all provisions usually were traders. Currently, the Unification of Private Law, according to the monistic conception embraced by NCC there are a series of difficulties in the conceptual framework of "professionals", the "company" and, especially, the professional traders. Professional traders are individuals: the individual, authorized individual and family business. The legal status of the three categories of individuals falling into the category of professionals traders is regulated by Ordinance no. 44/2008, amended.

  18. Pituitary control of branchial NCC, NKCC and Na(+), K (+)-ATPase α-subunit gene expression in Nile tilapia, Oreochromis niloticus.

    Science.gov (United States)

    Breves, Jason P; Seale, Andre P; Moorman, Benjamin P; Lerner, Darren T; Moriyama, Shunsuke; Hopkins, Kevin D; Grau, E Gordon

    2014-05-01

    This study investigated endocrine control of branchial ionoregulatory function in Nile tilapia (Oreochromis niloticus) by prolactin (Prl188 and Prl177), growth hormone (Gh) and cortisol. Branchial expression of Na(+)/Cl(-) cotransporter (ncc) and Na(+)/K(+)/2Cl(-) cotransporter (nkcc) genes were employed as specific markers for freshwater- and seawater-type ionocytes, respectively. We further investigated whether Prl, Gh and cortisol direct expression of two Na(+), K(+)-ATPase (nka)-α1 subunit genes, denoted nka-α1a and nka-α1b. Tilapia transferred to fresh water following hypophysectomy failed to adequately activate gill ncc expression; ncc expression was subsequently restored by Prl replacement. Prl188 and Prl177 stimulated ncc expression in cultured gill filaments in a concentration-related manner, suggesting that ncc is regulated by Prl in a gill-autonomous fashion. Tilapia transferred to brackish water (23 ‰) following hypophysectomy exhibited a reduced capacity to up-regulate nka-α1b expression. However, Gh and cortisol failed to affect nka-α1b expression in vivo. Similarly, we found no clear effects of Gh or cortisol on nkcc expression both in vivo and in vitro. When considered with patterns previously described in euryhaline Mozambique tilapia (O. mossambicus), the current study suggests that ncc is a conserved target of Prl in tilapiine cichlids. In addition, we revealed contrasting dependencies upon the pituitary to direct nka-α1b expression in hyperosmotic environments between Nile and Mozambique tilapia.

  19. Combustion physics

    Science.gov (United States)

    Jones, A. R.

    1985-11-01

    Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

  20. Applied combustion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    From the title, the reader is led to expect a broad practical treatise on combustion and combustion devices. Remarkably, for a book of modest dimension, the author is able to deliver. The text is organized into 12 Chapters, broadly treating three major areas: combustion fundamentals -- introduction (Ch. 1), thermodynamics (Ch. 2), fluid mechanics (Ch. 7), and kinetics (Ch. 8); fuels -- coal, municipal solid waste, and other solid fuels (Ch. 4), liquid (Ch. 5) and gaseous (Ch. 6) fuels; and combustion devices -- fuel cells (Ch. 3), boilers (Ch. 4), Otto (Ch. 10), diesel (Ch. 11), and Wankel (Ch. 10) engines and gas turbines (Ch. 12). Although each topic could warrant a complete text on its own, the author addresses each of these major themes with reasonable thoroughness. Also, the book is well documented with a bibliography, references, a good index, and many helpful tables and appendices. In short, Applied Combustion does admirably fulfill the author`s goal for a wide engineering science introduction to the general subject of combustion.

  1. Building America Expert Meeting. Combustion Safety

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Larry [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States)

    2013-03-01

    This is an overview of "The Best Approach to Combustion Safety in a Direct Vent World," held June 28, 2012, in San Antonio, TX. The objective of this Expert Meeting was to identify gaps and barriers that need to be addressed by future research, and to develop data-driven technical recommendations for code updates so that a common approach for combustion safety can be adopted by all members of the building energy efficiency and code communities.

  2. Building America Expert Meeting: Combustion Safety

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L.

    2013-03-01

    This is a meeting overview of 'The Best Approach to Combustion Safety in a Direct Vent World', held June 28, 2012, in San Antonio, Texas. The objective of this Expert Meeting was to identify gaps and barriers that need to be addressed by future research, and to develop data-driven technical recommendations for code updates so that a common approach for combustion safety can be adopted by all members of the building energy efficiency and code communities.

  3. Embedding the Ni-SOD mimetic Ni-NCC within a polypeptide sequence alters the specificity of the reaction pathway.

    Science.gov (United States)

    Krause, Mary E; Glass, Amanda M; Jackson, Timothy A; Laurence, Jennifer S

    2013-01-07

    The unique metal abstracting peptide asparagine-cysteine-cysteine (NCC) binds nickel in a square planar 2N:2S geometry and acts as a mimic of the enzyme nickel superoxide dismutase (Ni-SOD). The Ni-NCC tripeptide complex undergoes rapid, site-specific chiral inversion to dld-NCC in the presence of oxygen. Superoxide scavenging activity increases proportionally with the degree of chiral inversion. Characterization of the NCC sequence within longer peptides with absorption, circular dichroism (CD), and magnetic CD (MCD) spectroscopies and mass spectrometry (MS) shows that the geometry of metal coordination is maintained, though the electronic properties of the complex are varied to a small extent because of bis-amide, rather than amine/amide, coordination. In addition, both Ni-tripeptide and Ni-pentapeptide complexes have charges of -2. This study demonstrates that the chiral inversion chemistry does not occur when NCC is embedded in a longer polypeptide sequence. Nonetheless, the superoxide scavenging reactivity of the embedded Ni-NCC module is similar to that of the chirally inverted tripeptide complex, which is consistent with a minor change in the reduction potential for the Ni-pentapeptide complex. Together, this suggests that the charge of the complex could affect the SOD activity as much as a change in the primary coordination sphere. In Ni-NCC and other Ni-SOD mimics, changes in chirality, superoxide scavenging activity, and oxidation of the peptide itself all depend on the presence of dioxygen or its reduced derivatives (e.g., superoxide), and the extent to which each of these distinct reactions occurs is ruled by electronic and steric effects that emenate from the organization of ligands around the metal center.

  4. Biofuels combustion.

    Science.gov (United States)

    Westbrook, Charles K

    2013-01-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  5. Expression and phosphorylation of the Na+-Cl- cotransporter NCC in vivo is regulated by dietary salt, potassium, and SGK1.

    Science.gov (United States)

    Vallon, Volker; Schroth, Jana; Lang, Florian; Kuhl, Dietmar; Uchida, Shinichi

    2009-09-01

    The Na-Cl cotransporter NCC is expressed in the distal convoluted tubule, activated by phosphorylation, and has been implicated in renal NaCl and K(+) homeostasis. The serum and glucocorticoid inducible kinase 1 (SGK1) contributes to renal NaCl retention and K(+) excretion, at least in part, by stimulating the epithelial Na(+) channel and Na(+)-K(+)-ATPase in the downstream segments of aldosterone-sensitive Na(+)/K(+) exchange. In this study we confirmed in wild-type mice (WT) that dietary NaCl restriction increases renal NCC expression and its phosphorylation at Thr(53), Thr(58), and Ser(71), respectively. This response, however, was attenuated in mice lacking SGK1 (Sgk1(-/-)), which may contribute to impaired NaCl retention in those mice. Total renal NCC expression and phosphorylation at Thr(53), Thr(58), and Ser(71) in WT were greater under low- compared with high-K(+) diet. This finding is consistent with a regulation of NCC to modulate Na(+) delivery to downstream segments of Na(+)/K(+) exchange, thereby modulating K(+) excretion. Dietary K(+)-dependent variation in renal expression of total NCC and phosphorylated NCC were not attenuated in Sgk1(-/-) mice. In fact, high-K(+) diet-induced NCC suppression was enhanced in Sgk1(-/-) mice. The hyperkalemia induced in Sgk1(-/-) mice by a high-K(+) diet may have augmented NCC suppression, thereby increasing Na(+) delivery and facilitating K(+) excretion in downstream segments of impaired Na(+)/K(+) exchange. In summary, changes in NaCl and K(+) intake altered NCC expression and phosphorylation, an observation consistent with a role of NCC in NaCl and K(+) homeostasis. The two maneuvers dissociated plasma aldosterone levels from NCC expression and phosphorylation, implicating additional regulators. Regulation of NCC expression and phosphorylation by dietary NaCl restriction appears to involve SGK1.

  6. WNK-SPAK-NCC cascade revisited: WNK1 stimulates the activity of the Na-Cl cotransporter via SPAK, an effect antagonized by WNK4.

    Science.gov (United States)

    Chávez-Canales, María; Zhang, Chong; Soukaseum, Christelle; Moreno, Erika; Pacheco-Alvarez, Diana; Vidal-Petiot, Emmanuelle; Castañeda-Bueno, María; Vázquez, Norma; Rojas-Vega, Lorena; Meermeier, Nicholas P; Rogers, Shaunessy; Jeunemaitre, Xavier; Yang, Chao-Ling; Ellison, David H; Gamba, Gerardo; Hadchouel, Juliette

    2014-11-01

    The with-no-lysine (K) kinases, WNK1 and WNK4, are key regulators of blood pressure. Their mutations lead to familial hyperkalemic hypertension (FHHt), associated with an activation of the Na-Cl cotransporter (NCC). Although it is clear that WNK4 mutants activate NCC via Ste20 proline-alanine-rich kinase, the mechanisms responsible for WNK1-related FHHt and alterations in NCC activity are not as clear. We tested whether WNK1 modulates NCC through WNK4, as predicted by some models, by crossing our recently developed WNK1-FHHt mice (WNK1(+/FHHt)) with WNK4(-/-) mice. Surprisingly, the activated NCC, hypertension, and hyperkalemia of WNK1(+/FHHt) mice remain in the absence of WNK4. We demonstrate that WNK1 powerfully stimulates NCC in a WNK4-independent and Ste20 proline-alanine-rich kinase-dependent manner. Moreover, WNK4 decreases the WNK1 and WNK3-mediated activation of NCC. Finally, the formation of oligomers of WNK kinases through their C-terminal coiled-coil domain is essential for their activity toward NCC. In conclusion, WNK kinases form a network in which WNK4 associates with WNK1 and WNK3 to regulate NCC. © 2014 American Heart Association, Inc.

  7. Effect of angiotensin II on the WNK-OSR1/SPAK-NCC phosphorylation cascade in cultured mpkDCT cells and in vivo mouse kidney.

    Science.gov (United States)

    Talati, Gulibaha; Ohta, Akihito; Rai, Tatemitsu; Sohara, Eisei; Naito, Shotaro; Vandewalle, Alain; Sasaki, Sei; Uchida, Shinichi

    2010-03-19

    In our recent study using Wnk4(D561A/+) knockin mice, we determined that the WNK-OSR1/SPAK-NaCl cotransporter (NCC) phosphorylation cascade is important for regulating NCC function in vivo. Phosphorylation of NCC was necessary for its plasma membrane localization. Previously, angiotensin II infusion was shown to increase apical membrane expression of NCC in rats. Therefore, we investigated whether angiotensin II was an upstream regulator for the WNK-OSR1/SPAK-NCC cascade in cultured cells and in vivo kidney. In mpkDCT cells, the phosphorylation of OSR1 and NCC was increased 30 min after the addition of angiotensin II (10(-9)-10(-7)M) but returned to baseline after 18 h. In mice, a 5-min infusion of angiotensin II (5 ng/g/min) increased NCC phosphorylation in the kidney at 30 min and 2h after the injection but returned to baseline 24h later. This increase was inhibited by angiotensin II receptor blocker (valsartan) but not by aldosterone receptor blocker (eplerenone). Ten-day infusions of angiotensin II (720 ng/day) also increased phosphorylation of OSR1 and NCC in the mouse kidney, and both valsartan and eplerenone inhibited the increased phosphorylation. Although angiotensin II is identified as an upstream regulator for the WNK-OSR1/SPAK-NCC cascade in vivo, aldosterone appears to be the major regulator of this signal cascade in the long-term regulation by angiotensin II. Copyright 2010 Elsevier Inc. All rights reserved.

  8. WNK4 inhibits plasma membrane targeting of NCC through regulation of syntaxin13 SNARE formation.

    Science.gov (United States)

    Chung, Woo Young; Park, Hyun Woo; Han, Jung Woo; Lee, Min Goo; Kim, Joo Young

    2013-12-01

    WNK4, a serine/threonine kinase, plays a critical role in the expression of membrane proteins in the cell surface; however, the underlying mechanism of WNK4 is not clear. Here, we demonstrate that WNK4 inhibits the fusion of plasma membrane delivering vesicle with sorting/recycling endosome through disrupting SNARE formation of syntaxin13, an endosomal t-SNARE and VAMP2, the v-SNARE in plasma membrane delivering vesicle. Their interaction and co-localization were enhanced by hyperosmotic stimulation which is known for WNK4 activation. The kinase domain of WNK4 interacts with the transmembrane domain (TM) of syntaxin13 and this interaction was abolished when the TM was replaced with that of syntaxin16. Interestingly, cell fractionation using sucrose gradients revealed that WNK4 inhibited the formation of the syntaxin13/VAMP2 SNARE complex in the endosomal compartment, but not syntaxin16/VAMP2 or syntaxin13/VAMP7. Syntaxin13 was not phosphorylated by WNK4 and WNK4KI also showed the same binding strength and similar inhibitory regulation on SNARE formation of syntaxin13. Physiological relevance of this mechanism was proved with the expression of NCC (Na(+) C1(-) co-transporter) in the cell surface. The inhibiting activity of WNK4 on surface expression of NCC was abolished by syntaxin13 siRNA transfection. These results suggest that WNK4 attenuates PM targeting of NCC proteins through regulation of syntaxin13 SNARE complex formation with VAMP2 in recycling and sorting endosome. © 2013.

  9. TECHNICAL DESIGN REPORT FOR A NOSECONE CALORIMETER (NCC) FOR THE PHENIX EXPERIMENT.

    Energy Technology Data Exchange (ETDEWEB)

    PHENIX EXPERIMENT; OBRIEN,E.; BOOSE, S.; CHIU, M.; JOHNSON, B.M.; KISTENEV, E.P.; LYNCH, D.; NOUICER, R.; PAK, R.; PISANI, R.; STOLL, S.P.; SUKHANOV, A.; WOODY, C.L.; LI, Z.; RADEKA, V.; RESCIA, S.; (PHENIX EXPERIMENT COLLABORATORS)

    2007-08-01

    A remarkable result has emerged from the first several years of data taking at RHIC--the high temperature and density phase of QCD matter created in heavy ion collisions at RHIC is best described as a near perfect fluid--the strongly interacting Quark-Gluon-Plasma (sQGP). This state is characterized by a small viscosity to entropy ratio, and a high density of color charges which induces huge energy losses of partons transversing the medium. The task for the future is to understand the characteristics of the sQGP, and perhaps more importantly--to gain some insight into how and why such a medium is created. The PHENIX detector has been one of the primary experimental tools at RHIC; in particular the electromagnetic calorimeter has been a critical component of many of the measurements leading to this discovery. The coverage of the present PHENIX electromagnetic calorimeter is rather limited, covering half the azimuth and -0.35< {eta} <0.35 Further progress requires larger coverage of electromagnetic calorimetry, both to increase the rate for low cross section phenomena, and to cover a broader range of pseudorapidity to study the rapidity dependence of the medium. A pair of Nosecone Calorimeters (NCC) has been designed covering both positive and negative rapidity regions 1< |{eta}| <3 of the PHENIX detector. The NCC will make it possible to perform tomographic studies of the jet energy dependence of energy loss and medium response, by using direct photons as trigger particles over a large rapidity range. The technique of correlating trigger hadrons with low momentum hadrons has been powerfully exploited at RHIC to study the evolution of back to back jets [1, 2] and hence the response of the medium. The NCC will make it possible to do such studies using direct photons as the trigger particles. The direct photon in such ''photon-jet'' events tags the transverse momentum of outgoing parton which then fragments into lower energy particles. Together with

  10. RESEARCH NOTE Static dielectric constant of the polarizable NCC water model

    Science.gov (United States)

    Millot, Jean-Christophe Soetens Marilia T. C. Martins Costa Claude

    The static dielectric constant epsilon0 of the ab initio water model NCC including polarizability (Niesar, U., Corongiu, G., Clementi, E., Kneller, G. R., and Bhattacharya, D. K., 1990, J. phys. Chem., 94, 7949) has been computed by molecular dynamics simulation at 25oC and a density of 1gcm-3. The long range electrostatic interactions are taken into account by the reaction field method. Values of 100 8 and 8ps are found for the static dielectric constant and dielectric relaxation time, respectively.

  11. Lactococcus lactis NCC 2287 Alleviates Food Allergic Manifestations in Sensitized Mice by Reducing IL-13 Expression Specifically in the Ileum

    Directory of Open Access Journals (Sweden)

    Adrian W. Zuercher

    2012-01-01

    Full Text Available Objective. Utilizing a food allergy murine model, we have investigated the intrinsic antiallergic potential of the Lactococcus lactis NCC 2287 strain. Methods. BALB/c mice were sensitized at weekly intervals with ovalbumin (OVA plus cholera toxin (CT by the oral route for 7 weeks. In this model, an oral challenge with a high dose of OVA at the end of the sensitization period leads to clinical symptoms. Lactococcus lactis NCC 2287 was given to mice via the drinking water during sensitization (prevention phase or after sensitization (management phase. Results. Lactococcus lactis NCC 2287 administration to sensitized mice strikingly reduced allergic manifestations in the management phase upon challenge, when compared to control mice. No preventive effect was observed with the strain. Lactococcus lactis NCC 2287 significantly decreased relative expression levels of the Th-2 cytokine, IL-13, and associated chemokines CCL11 (eotaxin-1 and CCL17 (TARC in the ileum. No effect was observed in the jejunum. Conclusion/Significance. These results taken together designate Lactococcus lactis NCC 2287 as a candidate probiotic strain appropriate in the management of allergic symptoms.

  12. Lactococcus lactis NCC 2287 Alleviates Food Allergic Manifestations in Sensitized Mice by Reducing IL-13 Expression Specifically in the Ileum

    Science.gov (United States)

    Zuercher, Adrian W.; Weiss, Marietta; Holvoet, Sébastien; Moser, Mireille; Moussu, Hélène; van Overtvelt, Laurence; Horiot, Stéphane; Moingeon, Philippe; Nutten, Sophie; Prioult, Guénolée; Singh, Anurag; Mercenier, Annick

    2012-01-01

    Objective. Utilizing a food allergy murine model, we have investigated the intrinsic antiallergic potential of the Lactococcus lactis NCC 2287 strain. Methods. BALB/c mice were sensitized at weekly intervals with ovalbumin (OVA) plus cholera toxin (CT) by the oral route for 7 weeks. In this model, an oral challenge with a high dose of OVA at the end of the sensitization period leads to clinical symptoms. Lactococcus lactis NCC 2287 was given to mice via the drinking water during sensitization (prevention phase) or after sensitization (management phase). Results. Lactococcus lactis NCC 2287 administration to sensitized mice strikingly reduced allergic manifestations in the management phase upon challenge, when compared to control mice. No preventive effect was observed with the strain. Lactococcus lactis NCC 2287 significantly decreased relative expression levels of the Th-2 cytokine, IL-13, and associated chemokines CCL11 (eotaxin-1) and CCL17 (TARC) in the ileum. No effect was observed in the jejunum. Conclusion/Significance. These results taken together designate Lactococcus lactis NCC 2287 as a candidate probiotic strain appropriate in the management of allergic symptoms. PMID:21961022

  13. Lactococcus lactis NCC 2287 alleviates food allergic manifestations in sensitized mice by reducing IL-13 expression specifically in the ileum.

    Science.gov (United States)

    Zuercher, Adrian W; Weiss, Marietta; Holvoet, Sébastien; Moser, Mireille; Moussu, Hélène; van Overtvelt, Laurence; Horiot, Stéphane; Moingeon, Philippe; Nutten, Sophie; Prioult, Guénolée; Singh, Anurag; Mercenier, Annick

    2012-01-01

    Utilizing a food allergy murine model, we have investigated the intrinsic antiallergic potential of the Lactococcus lactis NCC 2287 strain. BALB/c mice were sensitized at weekly intervals with ovalbumin (OVA) plus cholera toxin (CT) by the oral route for 7 weeks. In this model, an oral challenge with a high dose of OVA at the end of the sensitization period leads to clinical symptoms. Lactococcus lactis NCC 2287 was given to mice via the drinking water during sensitization (prevention phase) or after sensitization (management phase). Lactococcus lactis NCC 2287 administration to sensitized mice strikingly reduced allergic manifestations in the management phase upon challenge, when compared to control mice. No preventive effect was observed with the strain. Lactococcus lactis NCC 2287 significantly decreased relative expression levels of the Th-2 cytokine, IL-13, and associated chemokines CCL11 (eotaxin-1) and CCL17 (TARC) in the ileum. No effect was observed in the jejunum. These results taken together designate Lactococcus lactis NCC 2287 as a candidate probiotic strain appropriate in the management of allergic symptoms.

  14. Turbulent combustion

    Energy Technology Data Exchange (ETDEWEB)

    Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

  15. Assessment of Reduced-Kinetics Mechanisms for Combustion of Jet Fuel in CFD Applications

    Science.gov (United States)

    Ajmani, Kumud; Kundu, Krihna P.; Yungster, Shaye J.

    2014-01-01

    A computational effort was undertaken to analyze the details of fluid flow in Lean-Direct Injection (LDI) combustors for next-generation LDI design. The National Combustor Code (NCC) was used to perform reacting flow computations on single-element LDI injector configurations. The feasibility of using a reduced chemical-kinetics approach, which optimizes the reaction rates and species to model the emissions characteristics typical of lean-burning gas-turbine combustors, was assessed. The assessments were performed with Reynolds- Averaged Navier-Stokes (RANS) and Time-Filtered Navier Stokes (TFNS) time-integration, with a Lagrangian spray model with the NCC code. The NCC predictions for EINOx and combustor exit temperature were compared with experimental data for two different single-element LDI injector configurations, with 60deg and 45deg axially swept swirler vanes. The effects of turbulence-chemistry interaction on the predicted flow in a typical LDI combustor were studied with detailed comparisons of NCC TFNS with experimental data.

  16. Geochemistry of khondalites from the central portion of North China craton (NCC): implications for the continental cratonization in the Neoarchean

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Within the high-grade metamorphic basement, the central portion of North China Craton (NCC), a group of Neoarchean khondalites (KS) is identified. They are characterized by large ion lithophile elements (LILE) enrichment, lower abundances of Zr, Hf and Sr. Their rare earth element (REE) distribution has significant LREE enrichment and negative Eu anomalies. The protoliths of KS are interpreted as feldspathic quartzite, shale or pelite and carbonite, deposited in a shallow sea upon cratonic shelf distant from the land. KS's source region might be dominated by granitic rocks, with a minor amount of TTG, underwent comparatively severe chemical weathering. Considering relevent tectonic constraints, we suggest that khondalites from central portion of NCC, an important metamophosed sedimentary cover, are the most significant exogenetic marker of Neoarchean continental cratonization for NCC.

  17. Regulation of blood pressure and renal function by NCC and ENaC: lessons from genetically engineered mice.

    Science.gov (United States)

    Verouti, Sophia N; Boscardin, Emilie; Hummler, Edith; Frateschi, Simona

    2015-04-01

    The activity of the thiazide-sensitive Na(+)/Cl(-) cotransporter (NCC) and of the amiloride-sensitive epithelial Na(+) channel (ENaC) is pivotal for blood pressure regulation. NCC is responsible for Na(+) reabsorption in the distal convoluted tubule (DCT) of the nephron, while ENaC reabsorbs the filtered Na(+) in the late DCT and in the cortical collecting ducts (CCD) providing the final renal adjustment to Na(+) balance. Here, we aim to highlight the recent advances made using transgenic mouse models towards the understanding of the regulation of NCC and ENaC function relevant to the control of sodium balance and blood pressure. We thus like to pave the way for common mechanisms regulating these two sodium-transporting proteins and their potential implication in structural remodeling of the nephron segments and Na(+) and Cl(-) reabsorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. COMBUSTION SIMULATION IN A SPARK IGNITION ENGINE CYLINDER: EFFECTS OF AIR-FUEL RATIO ON THE COMBUSTION DURATION

    Directory of Open Access Journals (Sweden)

    Nureddin Dinler

    2010-01-01

    Full Text Available Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion equations were solved. The k-e turbulence model was employed. The fuel mass fraction transport equation was used for modeling of the combustion. For this purpose a computational fluid dynamics code was developed by using the finite volume method with FORTRAN programming code. The moving mesh was utilized to simulate the piston motion. The developed code simulates four strokes of engine continuously. In the case of laminar flow combustion, Arrhenius type combustion equations were employed. In the case of turbulent flow combustion, eddy break-up model was employed. Results were given for rich, stoichiometric, and lean mixtures in contour graphs. Contour graphs showed that lean mixture (l = 1.1 has longer combustion duration.

  19. ENaC activity in collecting ducts modulates NCC in cirrhotic mice.

    Science.gov (United States)

    Mordasini, David; Loffing-Cueni, Dominique; Loffing, Johannes; Beatrice, Rohrbach; Maillard, Marc P; Hummler, Edith; Burnier, Michel; Escher, Geneviève; Vogt, Bruno

    2015-12-01

    Cirrhosis is a frequent and severe disease, complicated by renal sodium retention leading to ascites and oedema. A better understanding of the complex mechanisms responsible for renal sodium handling could improve clinical management of sodium retention. Our aim was to determine the importance of the amiloride-sensitive epithelial sodium channel (ENaC) in collecting ducts in compensate and decompensate cirrhosis. Bile duct ligation was performed in control mice (CTL) and collecting duct-specific αENaC knockout (KO) mice, and ascites development, aldosterone plasma concentration, urinary sodium/potassium ratio and sodium transporter expression were compared. Disruption of ENaC in collecting ducts (CDs) did not alter ascites development, urinary sodium/potassium ratio, plasma aldosterone concentrations or Na,K-ATPase abundance in CCDs. Total αENaC abundance in whole kidney increased in cirrhotic mice of both genotypes and cleaved forms of α and γ ENaC increased only in ascitic mice of both genotypes. The sodium chloride cotransporter (NCC) abundance was lower in non-ascitic KO, compared to non-ascitic CTL, and increased when ascites appeared. In ascitic mice, the lack of αENaC in CDs induced an upregulation of total ENaC and NCC and correlated with the cleavage of ENaC subunits. This revealed compensatory mechanisms which could also take place when treating the patients with diuretics. These compensatory mechanisms should be considered for future development of therapeutic strategies.

  20. Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural from the waste liquid of acid hydrolysis NCC.

    Science.gov (United States)

    Sun, Yonghui; Liu, Pengtao; Liu, Zhong

    2016-05-20

    The principal goal of this work was to reuse the carbohydrates and recycle sulfuric acid in the waste liquid of acid hydrolysis nanocrystalline cellulose (NCC). Therefore, in this work, the optimizations of further hydrolysis of waste liquid of acid hydrolysis NCC and catalytic conversion of L4 to 5-hydroxymethylfurfural (5-HMF) were studied. Sulfuric acid was separated by spiral wound diffusion dialysis (SWDD). The results revealed that cellulose can be hydrolyze to glucose absolutely under the condition of temperature 35 °C, 3 h, and sulfuric acid's concentration 62 wt%. And 78.3% sulfuric acid was recovered by SWDD. The yield of 5-HMF was highest in aqueous solution under the optimal condition was as follows, temperature 160 °C, 3 h, and sulfuric acid's concentration 12 wt%. Then the effect of biphasic solvent systems catalytic conversion and inorganic salt as additives were still examined. The results showed that both of them contributed to prepare 5-HMF. The yield and selectivity of 5-HMF was up to 21.0% and 31.4%, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Vibration extraction based on fast NCC algorithm and high-speed camera.

    Science.gov (United States)

    Lei, Xiujun; Jin, Yi; Guo, Jie; Zhu, Chang'an

    2015-09-20

    In this study, a high-speed camera system is developed to complete the vibration measurement in real time and to overcome the mass introduced by conventional contact measurements. The proposed system consists of a notebook computer and a high-speed camera which can capture the images as many as 1000 frames per second. In order to process the captured images in the computer, the normalized cross-correlation (NCC) template tracking algorithm with subpixel accuracy is introduced. Additionally, a modified local search algorithm based on the NCC is proposed to reduce the computation time and to increase efficiency significantly. The modified algorithm can rapidly accomplish one displacement extraction 10 times faster than the traditional template matching without installing any target panel onto the structures. Two experiments were carried out under laboratory and outdoor conditions to validate the accuracy and efficiency of the system performance in practice. The results demonstrated the high accuracy and efficiency of the camera system in extracting vibrating signals.

  2. Advanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [NETL

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

  3. Data and the associated R code used to estimate health and economic burden of neurocysticercosis in India

    Science.gov (United States)

    Singh, B.B.; Khatkar, M.S.; Gill, J.P.S.; Dhand, N.K.

    2016-01-01

    This article contains epidemiological, demographic and other data used for estimating health and economic burden of neurocysticercosis (NCC)-associated active epilepsy in India [1]. Most of the data are embedded in the R-code used for analyses so that the reader is able to replicate the results or adapt the code to their own data. However, data used to conduct sensitivity analyses to evaluate the effect of changing important input values such as prevalence and per capita income on health and economic impact of NCC in India are included in tables. Results from sensitivity analyses are also presented in tables and figures. The paper also includes three scenarios with different age weighting (k) and time discounting (r) values used to estimate health and economic burden of NCC in India. The data for the scenario without any age weighting and time discounting are presented in “Estimation of the health and economic burden of neurocysticercosis in India” [1]. PMID:27054160

  4. Data and the associated R code used to estimate health and economic burden of neurocysticercosis in India.

    Science.gov (United States)

    Singh, B B; Khatkar, M S; Gill, J P S; Dhand, N K

    2016-06-01

    This article contains epidemiological, demographic and other data used for estimating health and economic burden of neurocysticercosis (NCC)-associated active epilepsy in India [1]. Most of the data are embedded in the R-code used for analyses so that the reader is able to replicate the results or adapt the code to their own data. However, data used to conduct sensitivity analyses to evaluate the effect of changing important input values such as prevalence and per capita income on health and economic impact of NCC in India are included in tables. Results from sensitivity analyses are also presented in tables and figures. The paper also includes three scenarios with different age weighting (k) and time discounting (r) values used to estimate health and economic burden of NCC in India. The data for the scenario without any age weighting and time discounting are presented in "Estimation of the health and economic burden of neurocysticercosis in India" [1].

  5. Analysis of host-inducing proteome changes in bifidobacterium longum NCC2705 grown in Vivo.

    Science.gov (United States)

    Yuan, Jing; Wang, Bin; Sun, Zhongke; Bo, Xin; Yuan, Xitong; He, Xiang; Zhao, Hongqing; Du, Xinying; Wang, Fang; Jiang, Zheng; Zhang, Ling; Jia, Leili; Wang, Yufei; Wei, Kaihua; Wang, Jie; Zhang, Xuemin; Sun, Yansong; Huang, Liuyu; Zeng, Ming

    2008-01-01

    To investigate the molecular mechanisms underlying the adaptation of Bifidobacterium longum to the intestinal tract, we utilized a new model for rabbit intestinal culture of B. longum and reported the changes in proteomic profiles after incubation in the in vivo environment. By 2D-PAGE coupled with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and/or electrospray ionization tandem mass spectrometry (ESI-MS/MS) analyses, proteomic profiles of B. longum strain NCC2705 grown in the in vivo and in vitro environments were compared. Confirmed by semiquantitative RT-PCR, which exhibited at least a 3-fold change or greater, 19 up-regulated proteins, 14 down-regulated proteins, and 4 proteins with mobility changes were identified during intestinal growth. These identified proteins include key stress proteins, metabolism-related proteins, and proteins related to translation. Our results indicate that some useful proteins are expressed at higher levels in cells during intestinal growth. These proteins reflected the adaptation of B. longum NCC2705 to the intestine, such as EF-Tu which contributes to the retention or attachment as a Bifidobacterium adhesin-like factor, bile salt hydrolase (BSH) which might play an important role in the molecular mechanisms for the initial interaction of probiotic with the intestinal environment, and stress proteins which defend B. longum against the action of bile salts and other harmful ingredients of the gastrointestinal tract (GIT). The most striking fact of our observation was that four proteins GlnA1, PurC, LuxS, and Pgk exhibit clear post-translational modification. Western blot (WB) analysis and Pro-Q Diamond staining revealed that substances of the GIT trigger Pgk and LuxS phosphorylation at Ser/Thr residues for bacteria grown in vivo. These proteins were identified for the first time as bifidobacterial phosphoproteins. Our data suggest that the phosphorylated autoinducer-2 production

  6. Phosphatidylinositol 3-kinase/Akt signaling pathway activates the WNK-OSR1/SPAK-NCC phosphorylation cascade in hyperinsulinemic db/db mice.

    Science.gov (United States)

    Nishida, Hidenori; Sohara, Eisei; Nomura, Naohiro; Chiga, Motoko; Alessi, Dario R; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2012-10-01

    Metabolic syndrome patients have insulin resistance, which causes hyperinsulinemia, which in turn causes aberrant increased renal sodium reabsorption. The precise mechanisms underlying this greater salt sensitivity of hyperinsulinemic patients remain unclear. Abnormal activation of the recently identified with-no-lysine kinase (WNK)-oxidative stress-responsive kinase 1 (OSR1)/STE20/SPS1-related proline/alanine-rich kinase (SPAK)-NaCl cotransporter (NCC) phosphorylation cascade results in the salt-sensitive hypertension of pseudohypoaldosteronism type II. Here, we report a study of renal WNK-OSR1/SPAK-NCC cascade activation in the db/db mouse model of hyperinsulinemic metabolic syndrome. Thiazide sensitivity was increased, suggesting greater activity of NCC in db/db mice. In fact, increased phosphorylation of OSR1/SPAK and NCC was observed. In both SpakT243A/+ and Osr1T185A/+ knock-in db/db mice, which carry mutations that disrupt the signal from WNK kinases, increased phosphorylation of NCC and elevated blood pressure were completely corrected, indicating that phosphorylation of SPAK and OSR1 by WNK kinases is required for the increased activation and phosphorylation of NCC in this model. Renal phosphorylated Akt was increased in db/db mice, suggesting that increased NCC phosphorylation is regulated by the phosphatidylinositol 3-kinase/Akt signaling cascade in the kidney in response to hyperinsulinemia. A phosphatidylinositol 3-kinase inhibitor (NVP-BEZ235) corrected the increased OSR1/SPAK-NCC phosphorylation. Another more specific phosphatidylinositol 3-kinase inhibitor (GDC-0941) and an Akt inhibitor (MK-2206) also inhibited increased NCC phosphorylation. These results indicate that the phosphatidylinositol 3-kinase/Akt signaling pathway activates the WNK-OSR1/SPAK-NCC phosphorylation cascade in db/db mice. This mechanism may play a role in the pathogenesis of salt-sensitive hypertension in human hyperinsulinemic conditions, such as the metabolic syndrome.

  7. PI3K/Akt Signaling Pathway Activates the WNK-OSR1/SPAK-NCC Phosphorylation Cascade in Hyperinsulinemic db/db Mice

    Science.gov (United States)

    Nishida, Hidenori; Sohara, Eisei; Nomura, Naohiro; Chiga, Motoko; Alessi, Dario R; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2013-01-01

    Metabolic syndrome patients have insulin resistance, which causes hyperinsulinemia, which in turn causes aberrant increased renal sodium reabsorption. The precise mechanisms underlying this greater salt-sensitivity of hyperinsulinemic patients remain unclear. Abnormal activation of the recently-identified WNK kinase-OSR1/SPAK kinases-NCC transporter phosphorylation cascade results in the salt-sensitive hypertension of pseudohypoaldosteronism type II. Here, we report a study of renal WNK-OSR1/SPAK-NCC cascade activation in the db/db mouse model of hyperinsulinemic metabolic syndrome. Thiazide sensitivity was increased, suggesting greater activity of NCC in db/db mice. In fact, increased phosphorylation of OSR1/SPAK and NCC was observed. In both SpakT243A/+ and Osr1T185A/+ knock-in db/db mice, which carry mutations that disrupt the signal from WNK kinases, increased phosphorylation of NCC and elevated blood pressure were completely corrected, indicating that phosphorylation of SPAK and OSR1 by WNK kinases is required for the increased activation and phosphorylation of NCC in this model. Renal phosphorylated Akt was increased in db/db mice, suggesting that increased NCC phosphorylation is regulated by the PI3K/Akt signaling cascade in the kidney in response to hyperinsulinemia. A PI3K inhibitor (NVP-BEZ235) corrected the increased OSR1/SPAK-NCC phosphorylation. Another more specific PI3K inhibitor (GDC-0941) and an Akt inhibitor (MK-2206) also inhibited increased NCC phosphorylation. These results indicate that the PI3K/Akt signaling pathway activates the WNK-OSR1/SPAK-NCC phosphorylation cascade in db/db mice. This mechanism may play a role in the pathogenesis of salt-sensitive hypertension in human hyperinsulinemic conditions such as the metabolic syndrome. PMID:22949526

  8. The Probiotic Lactobacillus johnsonii NCC 533 produces high-molecular-mass inulin from sucrose by using an inulosucrase enzyme

    NARCIS (Netherlands)

    Anwar, Munir A.; Kralj, Slavko; van der Maarel, Marc J. E. C.; Dijkhuizen, Lubbert

    Fructansucrase enzymes polymerize the fructose moiety of sucrose into levan or inulin fructans, with beta(2-6) and beta(2-1) linkages, respectively. The probiotic bacterium Lactobacillus johnsonii strain NCC 533 possesses a single fructansucrase gene (open reading frame AAS08734) annotated as a

  9. The Assessment Supplement: A Faculty-Designed Addition to NCC's Manual, "Concepts & Procedures for Academic Assessment." First Edition.

    Science.gov (United States)

    Nassau Community Coll., Garden City, NY.

    This document is the first in a series of annual, faculty-designed supplements to Nassau Community College's (NCC's) (New York) manual, "Concepts & Procedures for Academic Assessment." The supplements are intended to provide faculty a forum through which they can communicate assessment designs and the impacts of those designs on…

  10. Using CLIPS in a distributed system: The Network Control Center (NCC) expert system

    Science.gov (United States)

    Wannemacher, Tom

    1990-01-01

    This paper describes an intelligent troubleshooting system for the Help Desk domain. It was developed on an IBM-compatible 80286 PC using Microsoft C and CLIPS and an AT&T 3B2 minicomputer using the UNIFY database and a combination of shell script, C programs and SQL queries. The two computers are linked by a lan. The functions of this system are to help non-technical NCC personnel handle trouble calls, to keep a log of problem calls with complete, concise information, and to keep a historical database of problems. The database helps identify hardware and software problem areas and provides a source of new rules for the troubleshooting knowledge base.

  11. Renal tubular NEDD4-2 deficiency causes NCC-mediated salt-dependent hypertension.

    Science.gov (United States)

    Ronzaud, Caroline; Loffing-Cueni, Dominique; Hausel, Pierrette; Debonneville, Anne; Malsure, Sumedha Ram; Fowler-Jaeger, Nicole; Boase, Natasha A; Perrier, Romain; Maillard, Marc; Yang, Baoli; Stokes, John B; Koesters, Robert; Kumar, Sharad; Hummler, Edith; Loffing, Johannes; Staub, Olivier

    2013-02-01

    The E3 ubiquitin ligase NEDD4-2 (encoded by the Nedd4L gene) regulates the amiloride-sensitive epithelial Na+ channel (ENaC/SCNN1) to mediate Na+ homeostasis. Mutations in the human β/γENaC subunits that block NEDD4-2 binding or constitutive ablation of exons 6-8 of Nedd4L in mice both result in salt-sensitive hypertension and elevated ENaC activity (Liddle syndrome). To determine the role of renal tubular NEDD4-2 in adult mice, we generated tetracycline-inducible, nephron-specific Nedd4L KO mice. Under standard and high-Na+ diets, conditional KO mice displayed decreased plasma aldosterone but normal Na+/K+ balance. Under a high-Na+ diet, KO mice exhibited hypercalciuria and increased blood pressure, which were reversed by thiazide treatment. Protein expression of βENaC, γENaC, the renal outer medullary K+ channel (ROMK), and total and phosphorylated thiazide-sensitive Na+Cl- cotransporter (NCC) levels were increased in KO kidneys. Unexpectedly, Scnn1a mRNA, which encodes the αENaC subunit, was reduced and proteolytic cleavage of αENaC decreased. Taken together, these results demonstrate that loss of NEDD4-2 in adult renal tubules causes a new form of mild, salt-sensitive hypertension without hyperkalemia that is characterized by upregulation of NCC, elevation of β/γENaC, but not αENaC, and a normal Na+/K+ balance maintained by downregulation of ENaC activity and upregulation of ROMK.

  12. NCC-RANSAC: a fast plane extraction method for 3-D range data segmentation.

    Science.gov (United States)

    Qian, Xiangfei; Ye, Cang

    2014-12-01

    This paper presents a new plane extraction (PE) method based on the random sample consensus (RANSAC) approach. The generic RANSAC-based PE algorithm may over-extract a plane, and it may fail in case of a multistep scene where the RANSAC procedure results in multiple inlier patches that form a slant plane straddling the steps. The CC-RANSAC PE algorithm successfully overcomes the latter limitation if the inlier patches are separate. However, it fails if the inlier patches are connected. A typical scenario is a stairway with a stair wall where the RANSAC plane-fitting procedure results in inliers patches in the tread, riser, and stair wall planes. They connect together and form a plane. The proposed method, called normal-coherence CC-RANSAC (NCC-RANSAC), performs a normal coherence check to all data points of the inlier patches and removes the data points whose normal directions are contradictory to that of the fitted plane. This process results in separate inlier patches, each of which is treated as a candidate plane. A recursive plane clustering process is then executed to grow each of the candidate planes until all planes are extracted in their entireties. The RANSAC plane-fitting and the recursive plane clustering processes are repeated until no more planes are found. A probabilistic model is introduced to predict the success probability of the NCC-RANSAC algorithm and validated with real data of a 3-D time-of-flight camera-SwissRanger SR4000. Experimental results demonstrate that the proposed method extracts more accurate planes with less computational time than the existing RANSAC-based methods.

  13. The mineralocorticoid receptor (MR) regulates ENaC but not NCC in mice with random MR deletion.

    Science.gov (United States)

    Czogalla, Jan; Vohra, Twinkle; Penton, David; Kirschmann, Moritz; Craigie, Eilidh; Loffing, Johannes

    2016-05-01

    Aldosterone binds to the mineralocorticoid receptor (MR) and increases renal Na(+) reabsorption via up-regulation of the epithelial Na(+) channel (ENaC) and the Na(+)-K(+)-ATPase in the collecting system (CS) and possibly also via the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). However, whether aldosterone directly regulates NCC via MR or indirectly through systemic alterations remains controversial. We used mice with deletion of MR in ∼20 % of renal tubule cells (MR/X mice), in which MR-positive (MR(wt)) and -negative (MR(ko)) cells can be studied side-by-side in the same physiological context. Adult MR/X mice showed similar mRNA and protein levels of renal ion transport proteins to control mice. In MR/X mice, no differences in NCC abundance and phosphorylation was seen between MR(wt) and MR(ko) cells and dietary Na(+) restriction up-regulated NCC to similar extent in both groups of cells. In contrast, MR(ko) cells in the CS did not show any detectable alpha-ENaC abundance or apical targeting of ENaC neither on control diet nor in response to dietary Na(+) restriction. Furthermore, Na(+)-K(+)-ATPase expression was unaffected in MR(ko) cells of the DCT, while it was lost in MR(ko) cells of the CS. In conclusion, MR is crucial for ENaC and Na(+)-K(+)-ATPase regulation in the CS, but is dispensable for NCC and Na(+)-K(+)-ATPase regulation in the DCT.

  14. WNK3-SPAK interaction is required for the modulation of NCC and other members of the SLC12 family.

    Science.gov (United States)

    Pacheco-Alvarez, Diana; Vázquez, Norma; Castañeda-Bueno, María; de-Los-Heros, Paola; Cortes-González, César; Moreno, Erika; Meade, Patricia; Bobadilla, Norma A; Gamba, Gerardo

    2012-01-01

    The serine/threonine with no lysine kinase 3 (WNK3) modulates the activity of the electroneutral cation-coupled chloride cotransporters (CCC) to promote Cl(-) influx and prevent Cl(-) efflux, thus fitting the profile for a putative "Cl(-)-sensing kinase". The Ste20-type kinases, SPAK/OSR1, become phosphorylated in response to reduction in intracellular chloride concentration and regulate the activity of NKCC1. Several studies have now shown that WNKs function upstream of SPAK/OSR1. This study was designed to analyze the role of WNK3-SPAK interaction in the regulation of CCCs with particular emphasis on NCC. In this study we used the functional expression system of Xenopus laevis oocytes to show that different SPAK binding sites in WNK3 ((241, 872, 1336)RFxV) are required for the kinase to have effects on CCCs. WNK3-F1337A no longer activated NKCC2, but the effects on NCC, NKCC1, and KCC4 were preserved. In contrast, the effects of WNK3 on these cotransporters were prevented in WNK3-F242A. The elimination of F873 had no consequence on WNK3 effects. WNK3 promoted NCC phosphorylation at threonine 58, even in the absence of the unique SPAK binding site of NCC, but this effect was abolished in the mutant WNK3-F242A. Thus, our data support the hypothesis that the effects of WNK3 upon NCC and other CCCs require the interaction and activation of the SPAK kinase. The effect is dependent on one of the three binding sites for SPAK that are present in WNK3, but not on the SPAK binding sites on the CCCs, which suggests that WNK3 is capable of binding both SPAK and CCCs to promote their phosphorylation. Copyright © 2012 S. Karger AG, Basel.

  15. Adenylyl cyclase 6 enhances NKCC2 expression and mediates vasopressin-induced phosphorylation of NKCC2 and NCC.

    Science.gov (United States)

    Rieg, Timo; Tang, Tong; Uchida, Shinichi; Hammond, H Kirk; Fenton, Robert A; Vallon, Volker

    2013-01-01

    Arginine vasopressin (AVP) affects kidney function via vasopressin V2 receptors that are linked to activation of adenylyl cyclase (AC) and an increase in cyclic adenosine monophosphate formation. AVP/cyclic adenosine monophosphate enhance the phosphorylation of the Na-K-2Cl cotransporter (NKCC2) at serine residue 126 (pS126 NKCC2) and of the Na-Cl cotransporter (NCC) at threonine 58 (pT58 NCC). The isoform(s) of AC involved in these responses, however, were unknown. Phosphorylation of S126 NKCC2 and T58 NCC, induced by the V2 receptor agonist (1-desamino-8-D-arginine vasopressin) in wild-type mice, is lacking in knockout mice for AC isoform 6 (AC6). With regard to NKCC2 phosphorylation, the stimulatory effect of 1-desamino-8-D-AVP and the defect in AC6(-/-) mice seem to be restricted to the medullary portion of the thick ascending limb. AC6 is also a stimulator of total renal NKCC2 protein abundance in medullary and cortical thick ascending limb. Consequently, mice lacking AC6 have lower NKCC2 expression and a mild Bartter syndrome-like phenotype, including lower plasma concentrations of K+ and H+ and compensatory upregulation of NCC. Increased AC6-independent phosphorylation of NKCC2 at S126 might help to stabilize NKCC2 activity in the absence of AC6. Renal AC6 determines total NKCC2 expression and mediates vasopressin-induced NKCC2/NCC phosphorylation. These regulatory mechanisms, which are defective in AC knockout mice, are likely responsible for the observed mild Bartter syndrome. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  16. Combustion Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Combustion Research Laboratory facilitates the development of new combustion systems or improves the operation of existing systems to meet the Army's mission for...

  17. High Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL's High-Pressure Combustion Research Facility in Morgantown, WV, researchers can investigate new high-pressure, high-temperature hydrogen turbine combustion...

  18. Combustion chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  19. P2Y2 receptor activation inhibits the expression of the sodium-chloride cotransporter NCC in distal convoluted tubule cells.

    Science.gov (United States)

    Gailly, P; Szutkowska, M; Olinger, E; Debaix, H; Seghers, F; Janas, S; Vallon, V; Devuyst, O

    2014-11-01

    Luminal nucleotide stimulation is known to reduce Na(+) transport in the distal nephron. Previous studies suggest that this mechanism may involve the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC), which plays an essential role in NaCl reabsorption in the cells lining the distal convoluted tubule (DCT). Here we show that stimulation of mouse DCT (mDCT) cells with ATP or UTP promoted Ca(2+) transients and decreased the expression of NCC at both mRNA and protein levels. Specific siRNA-mediated silencing of P2Y2 receptors almost completely abolished ATP/UTP-induced Ca(2+) transients and significantly reduced ATP/UTP-induced decrease of NCC expression. To test whether local variations in the intracellular Ca(2+) concentration ([Ca(2+)]i) may control NCC transcription, we overexpressed the Ca(2+)-binding protein parvalbumin selectively in the cytosol or in the nucleus of mDCT cells. The decrease in NCC mRNA upon nucleotide stimulation was abolished in cells overexpressing cytosolic PV but not in cells overexpressing either a nuclear-targeted PV or a mutated PV unable to bind Ca(2+). Using a firefly luciferase reporter gene strategy, we observed that the activity of NCC promoter region from -1 to -2,200 bp was not regulated by changes in [Ca(2+)]i. In contrast, high cytosolic calcium level induced instability of NCC mRNA. We conclude that in mDCT cells: (1) P2Y2 receptor is essential for the intracellular Ca(2+) signaling induced by ATP/UTP stimulation; (2) P2Y2-mediated increase of cytoplasmic Ca(2+) concentration down-regulates the expression of NCC; (3) the decrease of NCC expression occurs, at least in part, via destabilization of its mRNA.

  20. Large eddy simulation and combustion instabilities; Simulation des grandes echelles et instabilites de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lartigue, G.

    2004-11-15

    The new european laws on pollutants emission impose more and more constraints to motorists. This is particularly true for gas turbines manufacturers, that must design motors operating with very fuel-lean mixtures. Doing so, pollutants formation is significantly reduced but the problem of combustion stability arises. Actually, combustion regimes that have a large excess of air are naturally more sensitive to combustion instabilities. Numerical predictions of these instabilities is thus a key issue for many industrial involved in energy production. This thesis work tries to show that recent numerical tools are now able to predict these combustion instabilities. Particularly, the Large Eddy Simulation method, when implemented in a compressible CFD code, is able to take into account the main processes involved in combustion instabilities, such as acoustics and flame/vortex interaction. This work describes a new formulation of a Large Eddy Simulation numerical code that enables to take into account very precisely thermodynamics and chemistry, that are essential in combustion phenomena. A validation of this work will be presented in a complex geometry (the PRECCINSTA burner). Our numerical results will be successfully compared with experimental data gathered at DLR Stuttgart (Germany). Moreover, a detailed analysis of the acoustics in this configuration will be presented, as well as its interaction with the combustion. For this acoustics analysis, another CERFACS code has been extensively used, the Helmholtz solver AVSP. (author)

  1. Activation of nonspecific cytotoxic cells (NCC) with synthetic oligodeoxynucleotides and bacterial genomic DNA: binding, specificity and identification of unique immunostimulatory motifs.

    Science.gov (United States)

    Oumouna, M; Jaso-Friedmann, L; Evans, D L

    2002-04-01

    We have analyzed the effects of synthetic oligodeoxynucleotides (sODNs) and bacterial DNA (bDNA) on the in vitro activation of NCC. Teleost NCC recognition of DNA appeared to differ from that which occurs in higher vertebrates. NCC contain at least two different receptor specificities for DNA. Both oligodeoxyguanosine 20-mers (dG20) and 5'-TGCTGCTTGTGCTTGTGCTT-3' (4GC-2T) bound specifically to NCC. The existence of different receptor specificities was indicated by reciprocal cold target inhibition experiments. dG20 competed with 4GC-2T binding but sODNs composed of GpC or CpG nests did not compete with recognition by NCC of the dG20. ODN binding by NCC primarily depended on the presence of GpC or CpG nests with a preference for -G- serving as the anchor nucleotide. Secondarily, and similar to models of ODN activation in mammals, palindrome sequences of pu-pu-CpG-py-py activated NCC cytotoxicity. Additional analysis of the requirements for ODN activation indicated that guanosine could not substitute for adenosine as a purine spacer and that CpG motifs containing flanking thymidine (i.e.-GTCpGTT-) augmented the activity of the sODN containing this flanking base. Other evidence for the participation of both G and C in the recognition of specific nucleotides by NCC was that poly-dC20, dA20 or dT20 had no activating properties. Methylation of all cytosine nucleotides within an ODN abrogated activation. A canonical ODN motif of 5'-C/AT/AGCTT-3' can now be suggested for teleosts. Additional studies were done to examine the effects of in vitro treatment of NCC with bDNA. bDNA from three different disease isolates of Streptococcus iniae activated NCC cytotoxicity. Treatment of the bDNA with DNase abrogated the enhancement of cytotoxicity. Also, treatment of NCC with eukaryotic DNA had no effects on cytotoxicity. These studies suggested that NCC recognize bacterial nonmethylated DNA. The consequences of these interactions may be increased innate and acquired anti

  2. Oxygen-enhanced combustion

    CERN Document Server

    Baukal, Charles E

    2013-01-01

    Combustion technology has traditionally been dominated by air/fuel combustion. However, two developments have increased the significance of oxygen-enhanced combustion-new technologies that produce oxygen less expensively and the increased importance of environmental regulations. Advantages of oxygen-enhanced combustion include less pollutant emissions as well as increased energy efficiency and productivity. Oxygen-Enhanced Combustion, Second Edition compiles information about using oxygen to enhance industrial heating and melting processes. It integrates fundamental principles, applications, a

  3. A minor role of WNK3 in regulating phosphorylation of renal NKCC2 and NCC co-transporters in vivo.

    Science.gov (United States)

    Oi, Katsuyuki; Sohara, Eisei; Rai, Tatemitsu; Misawa, Moko; Chiga, Motoko; Alessi, Dario R; Sasaki, Sei; Uchida, Shinichi

    2012-02-15

    Mutations in WNK1 and WNK4 kinase genes have been shown to cause a human hereditary hypertensive disease, pseudohypoaldosteronism type II (PHAII). We previously discovered that WNK kinases phosphorylate and activate OSR1/SPAK kinases that regulate renal SLC12A family transporters such as NKCC2 and NCC, and clarified that the constitutive activation of this cascade causes PHAII. WNK3, another member of the WNK kinase family, was reported to be a strong activator of NCC/NKCC2 when assayed in Xenopus oocytes, suggesting that WNK3 also plays a major role in regulating blood pressure and sodium reabsorption in the kidney. However, it remains to be determined whether WNK3 is in fact involved in the regulation of these transporters in vivo. To clarify this issue, we generated and analyzed WNK3 knockout mice. Surprisingly, phosphorylation and expression of OSR1, SPAK, NKCC2 and NCC did not decrease in knockout mouse kidney under normal and low-salt diets. Similarly, expression of epithelial Na channel and Na/H exchanger 3 were not affected in knockout mice. Na(+) and K(+) excretion in urine in WNK3 knockout mice was not affected under different salt diets. Blood pressure in WNK3 knockout mice was not lower under normal diet. However, lower blood pressure was observed in WNK3 knockout mice fed low-salt diet. WNK4 and WNK1 expression was slightly elevated in the knockout mice under low-salt diet, suggesting compensation for WNK3 knockout by these WNKs. Thus, WNK3 may have some role in the WNK-OSR1/SPAK-NCC/NKCC2 signal cascade in the kidney, but its contribution to total WNK kinase activity may be minimal.

  4. Chronic candesartan alters expression and activity of NKCC2, NCC, and ENaC in the obese Zucker rat.

    Science.gov (United States)

    Madala Halagappa, Veerendra K; Tiwari, Swasti; Riazi, Shahla; Hu, Xinqun; Ecelbarger, Carolyn M

    2008-05-01

    The obese Zucker rat reportedly has increased activity of the intrarenal renin-angiotensin-aldosterone system, which conceptually could contribute to elevated salt sensitivity and blood pressure (BP). Our aim was to determine whether there was increased angiotensin II type 1 receptor (AT(1)R)-mediated upregulation of expression or activity of the bumetanide-sensitive Na-K-2Cl cotransporter, the thiazide-sensitive Na-Cl cotransporter (NCC), and/or the epithelial sodium channel (ENaC) in obese vs. lean Zucker rats. Male obese and lean Zucker rats (10-wk old) were fed either 1) control chow (1% NaCl) or 2) chow with candesartan (CAN), an AT(1)R antagonist (25 mg/kg.diet) for 14 wk (n = 8/treatment/body type). BP measured by radiotelemetry, was markedly reduced by CAN ( approximately 20-25 mmHg) in both lean and obese rats with no body-type differences. Obese rats had significantly greater net natriuretic response to single injections of hydrochlorothiazide and benzamil, suggesting increased activity of NCC and ENaC, respectively; however, only the response to benzamil was reduced by CAN. CAN led to a significant reduction in whole kidney levels of NCC and gamma-ENaC (70-kDa band) in both lean and obese rats. However, it significantly increased alpha-ENaC and Na-K-2Cl cotransporter levels, and these increases were greater in obese rats. These studies suggest that relatively increased ENaC, but not NCC activity, in obese rats is due to enhanced AT(1)R activity. CAN attenuated the reduction of several renal transporters in the obese rat kidney. Finally, differences in intrarenal AT(1)R activity do not seem directly responsible for BP differences between lean and obese rats.

  5. A minor role of WNK3 in regulating phosphorylation of renal NKCC2 and NCC co-transporters in vivo

    Directory of Open Access Journals (Sweden)

    Katsuyuki Oi

    2012-02-01

    Mutations in WNK1 and WNK4 kinase genes have been shown to cause a human hereditary hypertensive disease, pseudohypoaldosteronism type II (PHAII. We previously discovered that WNK kinases phosphorylate and activate OSR1/SPAK kinases that regulate renal SLC12A family transporters such as NKCC2 and NCC, and clarified that the constitutive activation of this cascade causes PHAII. WNK3, another member of the WNK kinase family, was reported to be a strong activator of NCC/NKCC2 when assayed in Xenopus oocytes, suggesting that WNK3 also plays a major role in regulating blood pressure and sodium reabsorption in the kidney. However, it remains to be determined whether WNK3 is in fact involved in the regulation of these transporters in vivo. To clarify this issue, we generated and analyzed WNK3 knockout mice. Surprisingly, phosphorylation and expression of OSR1, SPAK, NKCC2 and NCC did not decrease in knockout mouse kidney under normal and low-salt diets. Similarly, expression of epithelial Na channel and Na/H exchanger 3 were not affected in knockout mice. Na+ and K+ excretion in urine in WNK3 knockout mice was not affected under different salt diets. Blood pressure in WNK3 knockout mice was not lower under normal diet. However, lower blood pressure was observed in WNK3 knockout mice fed low-salt diet. WNK4 and WNK1 expression was slightly elevated in the knockout mice under low-salt diet, suggesting compensation for WNK3 knockout by these WNKs. Thus, WNK3 may have some role in the WNK-OSR1/SPAK-NCC/NKCC2 signal cascade in the kidney, but its contribution to total WNK kinase activity may be minimal.

  6. Biotransformation of caffeoyl quinic acids from green coffee extracts by Lactobacillus johnsonii NCC 533.

    Science.gov (United States)

    Bel-Rhlid, Rachid; Thapa, Dinesh; Kraehenbuehl, Karin; Hansen, Carl Erik; Fischer, Lutz

    2013-01-01

    The potential of Lactobacillus johnsonii NCC 533 to metabolize chlorogenic acids from green coffee extract was investigated. Two enzymes, an esterase and a hydroxycinnamate decarboxylase (HCD), were involved in this biotransformation. The complete hydrolysis of 5-caffeoylquinic acid (5-CQA) into caffeic acid (CA) by L. johnsonii esterase occurred during the first 16 h of reaction time. No dihydrocaffeic acid was identified in the reaction mixture. The decarboxylation of CA into 4-vinylcatechol (4-VC) started only when the maximum concentration of CA was reached (10 μmol/ml). CA was completely transformed into 4-VC after 48 h of incubation. No 4-vinylphenol or other derivatives could be identified in the reaction media. In this study we demonstrate the capability of L. johnsonii to transform chlorogenic acids from green coffee extract into 4-VC in two steps one pot reaction. Thus, the enzymatic potential of certain lactobacilli might be explored to generate flavor compounds from plant polyphenols.

  7. Implementation of a Surface Runoff Model with Horton and Dunne Mechanisms into the Regional Climate Model RegCM_NCC

    Institute of Scientific and Technical Information of China (English)

    SHI Xueli; XIE Zhenghui; LIU Yiming; YANG Hongwei

    2007-01-01

    A surface runoff parameterization scheme that dynamically represents both Horton and Dunne runoff generation mechanisms within a model grid cell together with a consideration of the subgrid-scale soil heterogeneity, is implemented into the National Climate Center regional climate model (RegCM_NCC). The effects of the modified surface runoff scheme on RegCM_NCC performance are tested with an abnormal heavy rainfall process which occurred in summer 1998. Simulated results show that the model with the original surface runoff scheme (noted as CTL) basically captures the spatial pattern of precipitation, circulation and land surface variables, but generally overestimates rainfall compared to observations. The model with the new surface runoff scheme (noted as NRM) reasonably reproduces the distribution pattern of various variables and effectively diminishes the excessive precipitation in the CTL. The processes involved in the improvement of NRM-simulated rainfall may be as follows: with the new surface runoff scheme, simulated surface runoff is larger, soil moisture and evaporation (latent heat flux) are decreased, the available water into the atmosphere is decreased; correspondingly, the atmosphere is drier and rainfall is decreased through various processes. Therefore, the implementation of the new runoff scheme into the RegCM_NCC has a significant effect on results at not only the land surface, but also the overlying atmosphere.

  8. Oral health knowledge, attitude and practice among NCC Navy Cadets and their correlation with oral hygiene in south India.

    Science.gov (United States)

    Singh, Abhinav

    2009-01-01

    The objective of the present study was to determine oral health knowledge, attitude and practice among National Cadet Corps (NCC) Navy Cadets and their correlation with oral hygiene in South India. A questionnaire study was conducted among 412 high school students who were voluntary participants of an NCC unit in South India. Knowledge, attitude and practice scores were calculated, and then were correlated with Simplified Oral Hygiene Index (OHI-S) values. Spearman's correlation test was used to measure the correlation. The significance value was set at P NCC Cadets' knowledge about gum diseases and the use of fluoride-containing dentifrice was found to be low, dental visits were infrequent and the consumption of sweets was found to be high. There was no correlation between knowledge and attitude scores with that of OHI-S, but a significant correlation was seen between practice and OHI-S scores. Most of the cadets did not have knowledge about the causes and the prevention of dental diseases. A significant number of participants sought further information, hence it can be said that the cadets had a positive attitude towards oral health. There was no correlation seen between knowledge and attitude scores with that of OHI-S measured, but a significant correlation was noted between practice and OHI-S scores.

  9. Combustion 2000

    Energy Technology Data Exchange (ETDEWEB)

    A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

    2001-06-30

    . To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization

  10. Combustion 2000

    Energy Technology Data Exchange (ETDEWEB)

    A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

    2001-06-30

    . To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization

  11. Proteogenomic analysis of NCC-S1M, a gastric cancer stem cell-like cell line that responds to anti-PD-1.

    Science.gov (United States)

    Park, Jun Won; Um, Hyejin; Yang, Hanna; Ko, Woori; Kim, Dae-Yong; Kim, Hark Kyun

    2017-03-11

    To elucidate signaling pathways that regulate gastric cancer stem cell (CSC) phenotypes and immune checkpoint, we performed a proteogenomic analysis of NCC-S1M, which is a gastric cancer cell line with CSC-like characteristics and is the only syngeneic gastric tumor cell line transplant model created in the scientific community. We found that the NCC-S1M allograft was responsive to anti-PD-1 treatment, and overexpressed Cd274 encoding PD-L1. PD-L1 was transcriptionally activated by loss of the TGF-β signaling. Il1rl1 protein was overexpressed in NCC-S1M cells compared with NCC-S1 cells that are less tumorigenic and less chemoresistant. Il1rl1 knockdown in NCC-S1M cells reduced tumorigenic potential and in vivo chemoresistance. Our proteogenomic analysis demonstrates a role of Smad4 loss in the PD-L1 immune evasion, as well as Il1rl1's role in CSC-like properties of NCC-S1M. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Transient combustion modeling of an oscillating lean premixed methane/air flam

    NARCIS (Netherlands)

    Withag, J.A.M.; Kok, Jacobus B.W.; Syed, Khawar

    2009-01-01

    The main objective of the present study is to demonstrate accurate low frequency transient turbulent combustion modeling. For accurate flame dynamics some improvements were made to the standard TFC combustion model for lean premixed combustion. With use of a 1D laminar flamelet code, predictions

  13. MCTP, a code for the thermo-mechanical analysis of a fuel rod of BWR type reactors (Neutron part); MCTP, un codigo para el analisis termo-mecanico de una barra combustible de reactores tipo BWR (Parte Neutronica)

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez L, H.; Ortiz V, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: hhl@nuclear.inin.mx

    2003-07-01

    In the National Institute of Nuclear Research of Mexico a code for the thermo-mechanical analysis of the fuel rods of the BWR type reactors of the Nucleo electric Central of Laguna Verde is developed. The code solves the diffusion equation in cylindrical coordinates with several energy groups. The code, likewise, calculates the temperature distribution and power distribution in those fuel rods. The code is denominated Multi groups With Temperatures and Power (MCTP). In the code, the energy with which the fission neutrons are emitted it is divided in six groups. They are also considered the produced perturbations by the changes in the temperatures of the materials that constitute the fuel rods, the content of fission products, the uranium consumption and in its case the gadolinium, as well as the plutonium production. In this work there are present preliminary results obtained with the code, using data of operation of the Nucleo electric Central of Laguna Verde. (Author)

  14. Expression of the sodium potassium chloride cotransporter (NKCC1) and sodium chloride cotransporter (NCC) and their effects on rat lens transparency.

    Science.gov (United States)

    Chee, K N; Vorontsova, I; Lim, J C; Kistler, J; Donaldson, P J

    2010-05-04

    To characterize the expression patterns of the Na+-K+-Cl(-) cotransporter (NKCC) 1 and NKCC2, and the Na+-Cl(-) cotransporter (NCC) in the rat lens and to determine if they play a role in regulating lens volume and transparency. RT-PCR was performed on RNA extracted from fiber cells to identify sodium dependent cotransporters expressed in the rat lens. Western blotting and immunohistochemistry, using NKCC1, NKCC2, and NCC antibodies, were used to verify expression at the protein level and to localize transporter expression. Organ cultured rat lenses were incubated in Artificial Aqueous Humor (AAH) of varying osmolarities or isotonic AAH that contained either the NKCC specific inhibitor bumetanide, or the NCC specific inhibitor thiazide for up to 18 h. Lens transparency was monitored with dark field microscopy, while tissue morphology and antibody labeling patterns were recorded using a confocal microscope. Molecular experiments showed that NKCC1 and NCC were expressed in the lens at both the transcript and protein levels, but NKCC2 was not. Immunohistochemistry showed that both NKCC1 and NCC were expressed in the lens cortex, but NCC expression was also found in the lens core. In the lens cortex the majority of labeling for both transporters was cytoplasmic in nature, while in the lens core, NCC labeling was associated with the membrane. Exposure of lenses to either hypotonic or hypertonic AAH had no noticeable effects on the predominantly cytoplasmic location of either transporter in the lens cortex. Incubation of lenses in isotonic AAH plus the NKCC inhibitor bumetanide for 18 h induced a cortical opacity that was initiated by a shrinkage of peripheral fiber cells and the dilation of the extracellular space between fiber cells in a deeper zone located some approximately 150 microm in from the capsule. In contrast, lenses incubated in isotonic AAH and the NCC inhibitor thiazide maintained both their transparency and their regular fiber cell morphology. We have

  15. On supersonic combustion

    Institute of Scientific and Technical Information of China (English)

    袁生学

    1999-01-01

    Some basic concepts and features of supersonic combustion are explained from the view point of macroscopic aerodynamics. Two kinds of interpretations of supersonic combustion are proposed. The difference between supersonic combustion and subsonic combustion is discussed, and the mechanism of supersonic combustion propagation and the limitation of heat addition in supersonic flow are pointed out. The results of the calculation of deflagration in supersonic flow show that the entropy increment and the total pressure loss of the combustion products may decrease with the increase of combustion velocity. It is also demonstrated that the oblique detonation wave angle may not be controlled by the wedge angle under weak underdriven solution conditions and be determined only by combustion velocity. Therefore, the weak underdriven solution may become self-sustaining oblique detonation waves with a constant wave angle.

  16. Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — For more than 30 years The Combustion Research Facility (CRF) has served as a national and international leader in combustion science and technology. The need for a...

  17. Integrated compensatory network is activated in the absence of NCC phosphorylation.

    Science.gov (United States)

    Grimm, P Richard; Lazo-Fernandez, Yoskaly; Delpire, Eric; Wall, Susan M; Dorsey, Susan G; Weinman, Edward J; Coleman, Richard; Wade, James B; Welling, Paul A

    2015-05-01

    Thiazide diuretics are used to treat hypertension; however, compensatory processes in the kidney can limit antihypertensive responses to this class of drugs. Here, we evaluated compensatory pathways in SPAK kinase-deficient mice, which are unable to activate the thiazide-sensitive sodium chloride cotransporter NCC (encoded by Slc12a3). Global transcriptional profiling, combined with biochemical, cell biological, and physiological phenotyping, identified the gene expression signature of the response and revealed how it establishes an adaptive physiology. Salt reabsorption pathways were created by the coordinate induction of a multigene transport system, involving solute carriers (encoded by Slc26a4, Slc4a8, and Slc4a9), carbonic anhydrase isoforms, and V-type H⁺-ATPase subunits in pendrin-positive intercalated cells (PP-ICs) and ENaC subunits in principal cells (PCs). A distal nephron remodeling process and induction of jagged 1/NOTCH signaling, which expands the cortical connecting tubule with PCs and replaces acid-secreting α-ICs with PP-ICs, were partly responsible for the compensation. Salt reabsorption was also activated by induction of an α-ketoglutarate (α-KG) paracrine signaling system. Coordinate regulation of a multigene α-KG synthesis and transport pathway resulted in α-KG secretion into pro-urine, as the α-KG-activated GPCR (Oxgr1) increased on the PP-IC apical surface, allowing paracrine delivery of α-KG to stimulate salt transport. Identification of the integrated compensatory NaCl reabsorption mechanisms provides insight into thiazide diuretic efficacy.

  18. Generation of neutron cross sections library for the Thermos code of the Fuel management System (FMS); Generacion de la biblioteca de secciones eficaces de neutrones para el codigo Thermos del sistema de administracion de combustible (FMS)

    Energy Technology Data Exchange (ETDEWEB)

    Alonso V, G.; Viais J, J. [ININ, Gcia. Sistemas Nucleares, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1990-10-15

    There is developed a method to generate the library of neutron cross sections for the Thermos code by means of the database ENDF-B/IV and the NJOY code. The obtained results are compared with the version previous of the library of neutron cross sections which was processed using the version ENDF-B/III. (Author)

  19. Generation of the library of neutron cross sections for the Record code of the Fuel Management System (FMS); Generacion de la biblioteca de secciones eficaces de neutrones para el codigo Record del Sistema de Administracion de Combustible (FMS)

    Energy Technology Data Exchange (ETDEWEB)

    Alonso V, G.; Hernandez L, H. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1991-11-15

    On the basis of the library structure of the RECORD code a method to generate the neutron cross sections by means of the ENDF-B/IV database and the NJOY code has been developed. The obtained cross sections are compared with those of the current library which was processed using the ENDF-B/III version. (Author)

  20. Thiazide-sensitive Na+ -Cl- cotransporter (NCC) gene inactivation results in increased duodenal Ca2+ absorption, enhanced osteoblast differentiation and elevated bone mineral density.

    Science.gov (United States)

    Hsu, Yu-Juei; Yang, Sung-Sen; Cheng, Chih-Jen; Liu, Shu-Ting; Huang, Shih-Ming; Chau, Tom; Chu, Pauling; Salter, Donald M; Lee, Herng-Sheng; Lin, Shih-Hua

    2015-01-01

    Inactivation of the thiazide-sensitive sodium chloride cotransporter (NCC) due to genetic mutations in Gitelman's syndrome (GS) or pharmacological inhibition with thiazide diuretics causes hypocalciuria and increased bone mineral density (BMD) with unclear extrarenal calcium (Ca(2+) ) regulation. We investigated intestinal Ca(2+) absorption and bone Ca(2+) metabolism in nonsense Ncc Ser707X (S707X) homozygous knockin mice (Ncc(S707X/S707X) mice). Compared to wild-type and heterozygous knockin littermates, Ncc(S707X/S707X) mice had increased intestinal absorption of (45) Ca(2+) and expression of the active Ca(2+) transport machinery (transient receptor potential vanilloid 6, calbindin-D9K , and plasma membrane Ca(2+) ATPase isoform 1b). Ncc(S707X/S707X) mice had also significantly increased Ca(2+) content accompanied by greater mineral apposition rate (MAR) in their femurs and higher trabecular bone volume, cortical bone thickness, and BMD determined by μCT. Their osteoblast differentiation markers, such as bone alkaline phosphatase, procollagen I, osteocalcin, and osterix, were also significantly increased while osteoclast activity was unaffected. Analysis of marrow-derived bone cells, either treated with thiazide or directly cultured from Ncc S707X knockin mice, showed that the differentiation of osteoblasts was associated with increased phosphorylation of mechanical stress-induced focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In conclusion, NCC inhibition stimulates duodenal Ca(2+) absorption as well as osteoblast differentiation and bone Ca(2+) storage, possibly through a FAK/ERK dependent mechanism. © 2014 American Society for Bone and Mineral Research.

  1. Oral administration of Lactobacillus paracasei NCC 2461 for the modulation of grass pollen allergic rhinitis: a randomized, placebo-controlled study during the pollen season.

    Science.gov (United States)

    Nembrini, Chiara; Singh, Anurag; De Castro, Carlos Antonio; Mercenier, Annick; Nutten, Sophie

    2015-01-01

    The efficacy of Lactobacillus paracasei NCC 2461 in modulating allergic rhinitis was previously evaluated in two exploratory clinical studies. Oral administration with NCC 2461 reduced specific subjective symptoms following nasal provocation tests with controlled grass pollen allergen concentrations. Our aim was to confirm the anti-allergic effect of NCC 2461 in grass pollen allergic subjects exposed to natural doses of allergens during the pollen season. A double-blind, randomized, placebo-controlled, parallel study was conducted with 131 grass pollen allergic subjects from May to July 2012 in concomitance with the pollen season in Berlin. NCC 2461 or placebo was administered daily for an 8-week period to adult subjects with clinical history of allergic rhinitis to grass pollen, positive skin prick test and IgE to grass pollen. During the 8 weeks, symptoms and quality of life questionnaires were filled out, and plasma was collected for IgE analysis at screening and at the end of the intervention. All subjects were included within a 5-day interval, ensuring exposure to similar air pollen counts for each individual during the trial period. The results obtained show that symptoms increased with pollen loads, confirming a natural exposure to the allergen and presence of pollen-induced allergic rhinitis in the subjects. However, no significant differences were observed in allergic rhinitis symptoms scores, quality of life, or specific IgE levels between subjects receiving NCC 2461 as compared to placebo administration. In contrast to previous findings, oral administration of NCC 2461 did not show a beneficial effect on allergic rhinitis in a field trial. The influence of study design, allergen exposure and intervention window on the efficacy of NCC 2461 in modulating respiratory allergy should be further evaluated.

  2. Numerical models for the phenomenological study of flameless combustion

    Directory of Open Access Journals (Sweden)

    Bernardo Argemiro Herrera Múnera

    2010-07-01

    Full Text Available Flameless combustion is a technique which offers environmental advantages such as lower than 100 ppm NOx and CO emis- sions due to below 200 K temperature gradients. Flameless combustion also supplies higher than 70% energy efficiency. Knowledge of the phenomena in this combustion regime has been facilitated by using numerical simulation. This paper reviewed the specialised literature about the most commonly used turbulence, combustion, heat transfer and NOx formation models in modelling flameless combustion with CFD codes. The review concluded that the k-ε standard model is the most used for turbu- lence. Finite rate/eddy dissipation with modified constants and eddy dissipation concept models are suitable for combustion reac- tions, discrete ordinates and weighted sum gray gas (WSGG models are used for radiation and thermal, prompt and N2O inter- mediate models are used for NOx.

  3. Analysis of high fidelity of a BWR fuel element with COBRA-TF/PARCS codes and TRACE; Analisis de Alta Fidelidad de un Elemento Combustible BWR con los codigos COBRA-TF/PARCS y TRACE

    Energy Technology Data Exchange (ETDEWEB)

    Abarca, A.; Miro, R.; Barrachina, T.; Verdu, G.; Solar, A.; Concejal, A.; Melara, J.; Albendea, M.

    2013-07-01

    It has been modeled a 10 x 10 BWR fuel element, containing 91 fuel rods (81 of 10 partial length and total length) and a great water bar of square section in the central part of it. Such fuel element has been modeled in detail: at the level of sub-channel code COBRA-TF and using parametric models for fuel elements BWR that owns the plant code TRACE. Has been an exercise in comparison of the results obtained by both codes in the simulation of a stationary and a small transient flow injection, highlighting the differences observed.

  4. Description of modelling to be implemented in the fuel rod thermomechanics code Cyrano3; Description des modeles a introduire dans le logiciel de thermomecanique du crayon combustible Cyrano3

    Energy Technology Data Exchange (ETDEWEB)

    Baron, D.; Bouffioux, P.

    1993-06-01

    CYRANO3 is the new EDF thermomechanical code developed to evaluate the overall fuel rod behavior under irradiation. In that context, this paper presents the phenomena to be simulated and the correlations adopted for modelling purposes. The empirical models presented are taken from the CYRANO2 code and a compilation of the relevant literature. The present revision corrects and supplements version B on the basis of its use during the software coding phase from January 1991 to May 1993. (authors). figs., tabs., 120 refs.

  5. NCC-AUC: an AUC optimization method to identify multi-biomarker panel for cancer prognosis from genomic and clinical data.

    Science.gov (United States)

    Zou, Meng; Liu, Zhaoqi; Zhang, Xiang-Sun; Wang, Yong

    2015-10-15

    In prognosis and survival studies, an important goal is to identify multi-biomarker panels with predictive power using molecular characteristics or clinical observations. Such analysis is often challenged by censored, small-sample-size, but high-dimensional genomic profiles or clinical data. Therefore, sophisticated models and algorithms are in pressing need. In this study, we propose a novel Area Under Curve (AUC) optimization method for multi-biomarker panel identification named Nearest Centroid Classifier for AUC optimization (NCC-AUC). Our method is motived by the connection between AUC score for classification accuracy evaluation and Harrell's concordance index in survival analysis. This connection allows us to convert the survival time regression problem to a binary classification problem. Then an optimization model is formulated to directly maximize AUC and meanwhile minimize the number of selected features to construct a predictor in the nearest centroid classifier framework. NCC-AUC shows its great performance by validating both in genomic data of breast cancer and clinical data of stage IB Non-Small-Cell Lung Cancer (NSCLC). For the genomic data, NCC-AUC outperforms Support Vector Machine (SVM) and Support Vector Machine-based Recursive Feature Elimination (SVM-RFE) in classification accuracy. It tends to select a multi-biomarker panel with low average redundancy and enriched biological meanings. Also NCC-AUC is more significant in separation of low and high risk cohorts than widely used Cox model (Cox proportional-hazards regression model) and L1-Cox model (L1 penalized in Cox model). These performance gains of NCC-AUC are quite robust across 5 subtypes of breast cancer. Further in an independent clinical data, NCC-AUC outperforms SVM and SVM-RFE in predictive accuracy and is consistently better than Cox model and L1-Cox model in grouping patients into high and low risk categories. In summary, NCC-AUC provides a rigorous optimization framework to

  6. Simulation of the heat transfer of a irradiated fuel storage container with code CFD STAR- CCM+; Simulacion de la transferencia de calor de un contenedor de almacenamiento de combustible irradiado con el codigo CFD STAR-CCM+

    Energy Technology Data Exchange (ETDEWEB)

    Barrera matalla, J. E.; Hernandez Gomez, J.; Riverala Gurruchaga, J.

    2012-07-01

    Irradiated fuel has become an object of interest in the industry by the importance of ensuring its safety during long periods of storage time. New containers, stores, methods and codes will be used to ensure a suitable cooling and residual heat removal, and secure the safety of fuel elements in dry storage. The codes CFD (Computational Fluid Dynamics) have great potential to help in design of containers and stores, improving thermal-hydraulic performance and the extraction of heat generated.

  7. Increased renal alpha-ENaC and NCC abundance and elevated blood pressure are independent of hyperaldosteronism in vasopressin escape.

    Science.gov (United States)

    Tiwari, Swasti; Packer, Randall K; Hu, Xinqun; Sugimura, Yoshihisa; Verbalis, Joseph G; Ecelbarger, Carolyn A

    2006-07-01

    Previously, we demonstrated that rats undergoing vasopressin escape had increased mean arterial blood pressure (MAP), plasma and urine aldosterone, and increased renal protein abundance of the alpha-subunit of the epithelial sodium channel (ENaC), the thiazide-sensitive Na-Cl cotransporter (NCC), and the 70-kDa band of gamma-ENaC (Song J, Hu X, Khan O, Tian Y, Verbalis JG, and Ecelbarger CA. Am J Physiol Renal Physiol 287: F1076-F1083, 2004; Ecelbarger CA, Knepper MA, and Verbalis JG. J Am Soc Nephrol 12: 207-217, 2001). Here, we determine whether changes in these renal proteins and MAP require elevated aldosterone levels. We performed adrenalectomies (ADX) or sham surgeries on male Sprague-Dawley rats. Corticosterone and aldosterone were replaced to clamp these hormone levels. MAP was monitored by radiotelemetry. Rats were infused with 1-deamino-[8-D-arginine]-vasopressin (dDAVP) via osmotic minipumps (5 ng/h). At day 3 of dDAVP infusion, seven rats in each group were offered a liquid diet [water load (WL)] or continued on a solid diet (SD). Plasma aldosterone and corticosterone and urine aldosterone were increased by WL in sham rats. ADX-WL rats escaped, as assessed by early natriuresis followed by diuresis; however, urine volume and natriuresis were somewhat blunted. WL did not reduce the abundance or activity of 11-beta-hydroxsteroid dehydrogenase type 2. Furthermore, the previously observed increase in renal aldosterone-sensitive proteins and escape-associated increased MAP persisted in clamped rats. The densitometry of immunoblots for NCC, alpha- and gamma-70 kDa ENaC, respectively, were (% sham-SD): sham-WL, 159, 278, 233; ADX-SD, 69, 212, 171; ADX-WL, 116, 302, 161. However, clamping corticosteroids blunted the rise at least for NCC and gamma-ENaC (70 kDa). Overall, the increase in aldosterone observed in vasopressin escape is not necessary for the increased expression of NCC, alpha- or gamma-ENaC or increased MAP associated with "escape."

  8. Generation and analysis of the thiazide-sensitive Na+ -Cl- cotransporter (Ncc/Slc12a3) Ser707X knockin mouse as a model of Gitelman syndrome.

    Science.gov (United States)

    Yang, Sung-Sen; Lo, Yi-Fen; Yu, I-Shing; Lin, Shu-Wha; Chang, Tai-Hsiang; Hsu, Yu-Juei; Chao, Tai-Kuang; Sytwu, Huey-Kang; Uchida, Shinichi; Sasaki, Sei; Lin, Shih-Hua

    2010-12-01

    Gitelman syndrome (GS) is characterized by salt-losing hypotension, hypomagnesemia, hypokalemic metabolic alkalosis, and hypocalciuria. To better model human GS caused by a specific mutation in the thiazide-sensitive Na(+) -Cl(-) cotransporter (NCC) gene SLC12A3, we generated a nonsense Ncc Ser707X knockin mouse corresponding to human p.Ser710X (c.2135C>A), a recurrent mutation with severe phenotypes in Chinese GS patients. Compared with wild-type or heterozygous littermates, homozygous (Hom) knockin mice fully recapitulated the phenotype of human GS. The markedly reduced Ncc mRNA and virtually absent Ncc protein expression in kidneys of Hom mice was primarily due to nonsense-mediated mRNA decay (NMD) surveillance mechanisms. Expression of epithelial Na(+) channel (Enac), Ca(2+) channels (Trpv5 and Trpv6), and K(+) channels (Romk1 and maxi-K) were significantly increased. Late distal convoluted tubules (DCT) volume was increased and DCT cell ultrastructure appeared intact. High K(+) intake could not correct hypokalemia but caused a further increase in maxi-K but not Romk1 expression. Renal tissue from a patient with GS also showed the enhanced TRPV5 and ROMK1 expression in distal tubules. We suggest that the upregulation of TRPV5/6 and of ROMK1 and Maxi-K may contribute to hypocalciuria and hypokalemia in Ncc Ser707X knockin mice and human GS, respectively. © 2010 Wiley-Liss, Inc.

  9. Boiler using combustible fluid

    Science.gov (United States)

    Baumgartner, H.; Meier, J.G.

    1974-07-03

    A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

  10. Simplified Two-Time Step Method for Calculating Combustion and Emission Rates of Jet-A and Methane Fuel With and Without Water Injection

    Science.gov (United States)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified kinetic scheme for Jet-A, and methane fuels with water injection was developed to be used in numerical combustion codes, such as the National Combustor Code (NCC) or even simple FORTRAN codes. The two time step method is either an initial time averaged value (step one) or an instantaneous value (step two). The switch is based on the water concentration in moles/cc of 1x10(exp -20). The results presented here results in a correlation that gives the chemical kinetic time as two separate functions. This two time step method is used as opposed to a one step time averaged method previously developed to determine the chemical kinetic time with increased accuracy. The first time averaged step is used at the initial times for smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, initial water to fuel mass ratio, temperature, and pressure. The second instantaneous step, to be used with higher water concentrations, gives the chemical kinetic time as a function of instantaneous fuel and water mole concentration, pressure and temperature (T4). The simple correlations would then be compared to the turbulent mixing times to determine the limiting rates of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. Chemical kinetic time equations for fuel, carbon monoxide and NOx are obtained for Jet-A fuel and methane with and without water injection to water mass loadings of 2/1 water to fuel. A similar correlation was also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium concentrations of carbon monoxide and nitrogen oxide as functions of overall equivalence ratio, water to fuel mass ratio, pressure and temperature (T3). The temperature of the gas entering

  11. New Reduced Two-Time Step Method for Calculating Combustion and Emission Rates of Jet-A and Methane Fuel With and Without Water Injection

    Science.gov (United States)

    Molnar, Melissa; Marek, C. John

    2004-01-01

    A simplified kinetic scheme for Jet-A, and methane fuels with water injection was developed to be used in numerical combustion codes, such as the National Combustor Code (NCC) or even simple FORTRAN codes that are being developed at Glenn. The two time step method is either an initial time averaged value (step one) or an instantaneous value (step two). The switch is based on the water concentration in moles/cc of 1x10(exp -20). The results presented here results in a correlation that gives the chemical kinetic time as two separate functions. This two step method is used as opposed to a one step time averaged method previously developed to determine the chemical kinetic time with increased accuracy. The first time averaged step is used at the initial times for smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, initial water to fuel mass ratio, temperature, and pressure. The second instantaneous step, to be used with higher water concentrations, gives the chemical kinetic time as a function of instantaneous fuel and water mole concentration, pressure and temperature (T4). The simple correlations would then be compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates were then used to calculate the necessary chemical kinetic times. Chemical kinetic time equations for fuel, carbon monoxide and NOx were obtained for Jet-A fuel and methane with and without water injection to water mass loadings of 2/1 water to fuel. A similar correlation was also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium concentrations of carbon monoxide and nitrogen oxide as functions of overall equivalence ratio, water to fuel mass ratio, pressure and temperature (T3

  12. Thermomechanical analysis of a fuel rod in a BWR reactor using the FUELSIM code; Analisis termomecanico de una barra de combustible de un reactor BWR utilizando el codigo FUELSIM

    Energy Technology Data Exchange (ETDEWEB)

    Pantoja C, R. [Escuela Superior de Fisica y Matematicas, Departamento de Ingenieria Nuclear, IPN, Av. Instituto Politecnico Nacional s/n, Col. San Pedro Zacatenco, 07738 Mexico, D. F. (Mexico); Ortiz V, J.; Araiza M, E. [ININ, Departamento de Sistemas Nucleares, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)], e-mail: rapaca78@yahoo.com.mx

    2009-10-15

    The thermomechanical behaviour of a fuel rod exposed to irradiation is a complex process in which are coupled great quantity of interrelated physical-chemical phenomena, for that analysis of rod performance in the core of a nuclear power reactor is realized generally with computation codes that integrate several phenomena expected during the time life of fuel rod in the core. An application of this type of thermomechanical codes is to predict, inside certain reliability margin, the design parameters that would be required to adjust, in order to get a better economy or rod performance, for a systematic approach to the fuel design optimization. FUELSIM is a thermomechanical code based on the models of FRAPCON code, which was developed under auspice of Nuclear Regulatory Commission of USA. FUELSIM allows iterative calculations like part of its programming structure, allowing search of extreme cases of behaviour, probabilistic analysis (or statistical), parametric analysis (or sensibility) and also can include as entrance data to the uncertainties associated with production data, code parameters and associated models. In this work is reported a first analysis of thermomechanical performance of a typical fuel rod used in a BWR 5/6. Results of maximum temperatures are presented in the fuel center and of axial deformation, for the 10 axial nodes in that the active longitude of fuel rod was divided. (Author)

  13. Geochemistry of khondalites from the central portion of North China craton (NCC):implications for the continental cratonization in the Neoarchean

    Institute of Scientific and Technical Information of China (English)

    李江海; 钱祥麟; 刘树文

    2000-01-01

    Within the high-grade metamorphic basement, the central portion of North China Craton (NCC), a group of Neoarchean khondalites (KS) is identified. They are characterized by large ion lithophile elements (LILE) enrichment, lower abundances of Zr, Hf and Sr. Their rare earth element (REE) distribution has significant LREE enrichment and negative Eu anomalies. The protoliths of KS are interpreted as feldspathic quartzite, shale or petite and carbonite, deposited in a shallow sea upon cratonic shelf distant from the land. KS’s source region might be dominated by granitic rocks, with a minor amount of TTG, underwent comparatively severe chemical weathering. Considering relevent tectonic constraints, we suggest that khondalites from central portion of NCC, an important metamophosed sedimentary cover, are the most significant exogenetic marker of Neoarchean continental cratonization for NCC.

  14. Use of genetic algorithms for optimization of subchannel simulations; Application des algorithmes genetiques pour l'optimisation d'un code d'analyse des sous-canaux d'une grappe de combustible nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Nava Dominguez, A

    2004-07-01

    To facilitate the modeling of a rod fuel bundle, the most common used method consist in dividing the complex cross-sectional area in small subsections called subchannels. To close the system equations, a mixture model is used to represent the intersubchannel interactions. These interactions are as follows: diversion cross-flow, turbulent void diffusion, void drift and buoyancy drift. Amongst these mechanisms, the turbulent void diffusion and void drift are frequently modelled using diffusion coefficients. In this work, a novel approach has been employed where an existing subchannel code coupled to a genetic algorithm code which were used to optimize these coefficients. After several numerical simulations, a new objective function based in the principle of minimum dissipated energy was developed. The use of this function in the genetic algorithm coupled to the subchannel code, gave results in good agreement with the experimental data.

  15. Coal combustion products

    Science.gov (United States)

    Kalyoncu, R.S.; Olson, D.W.

    2001-01-01

    Coal-burning powerplants, which supply more than half of U.S. electricity, also generate coal combustion products, which can be both a resource and a disposal problem. The U.S. Geological Survey collaborates with the American Coal Ash Association in preparing its annual report on coal combustion products. This Fact Sheet answers questions about present and potential uses of coal combustion products.

  16. Research Combustion Laboratory (RCL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Research Combustion Laboratory (RCL) develops aerospace propulsion technology by performing tests on propulsion components and materials. Altitudes up to 137,000...

  17. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    Ashlines: To promote and support the commercially viable and environmentally sound recycling of coal combustion byproducts for productive uses through scientific research, development, and field testing.

  18. Research Combustion Laboratory (RCL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Research Combustion Laboratory (RCL) develops aerospace propulsion technology by performing tests on propulsion components and materials. Altitudes up to 137,000...

  19. Compact Kinetic Mechanisms for Petroleum-Derived and Alternative Aviation Fuels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To be useful for computational combustor design and analysis using tools like the National Combustion Code (NCC), low-dimensional chemical kinetic mechanisms for...

  20. Coding Partitions

    Directory of Open Access Journals (Sweden)

    Fabio Burderi

    2007-05-01

    Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.

  1. Fuel management inside the reactor. Impact of the substitution of the basic libraries of the Eclipse and Record codes of the FMS system of fuel management; Administracion de combustible dentro del reactor. Impacto de la sustitucion de las bibliotecas basicas de los codigos Eclipse y Record del sistema FMS de administracion de combustible

    Energy Technology Data Exchange (ETDEWEB)

    Alonso V, G.; Hernandez L, H. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1992-12-15

    The present work is given to know the repercussions in the obtained results by the ECLIPSE-RECORD system of the package of fuel management FMS of SCANDPOWER, with the use of the libraries of effective sections of neutrons, for both codes, generated starting from the ENDF-B/IV database. Inside of the Institute it doesn't have any version of the ECLIPSE code it which drove us to make use of the versions of the THERMOS and GADPOL codes. The obtained results with the libraries generated were compared against those that are obtained making use of the libraries that it possesses the code, generated starting from the ENDF-B/III database, and the data that General Electric Co. reports for the cells that were used for this work. The calculations with the THERMOS-GADPOL-RECORD system, installed in 830 CDC machine of the Institute, its were carried out following the calculation sequence that it is continued during the generation of nuclear databases proposed by CFE only for the series 1 and 2. The obtained results are reported in the Appendixes B and C as well as some of the enter files for the codes used in the Appendix D, which are specified for those installed versions. (Author)

  2. Combustion Safety Simplified Test Protocol Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L [Gas Technology Inst., Des Plaines, IL (United States); Cautley, D. [Gas Technology Inst., Des Plaines, IL (United States); Bohac, D. [Gas Technology Inst., Des Plaines, IL (United States); Francisco, P. [Gas Technology Inst., Des Plaines, IL (United States); Shen, L. [Gas Technology Inst., Des Plaines, IL (United States); Gloss, S. [Gas Technology Inst., Des Plaines, IL (United States)

    2015-11-05

    "9Combustions safety is an important step in the process of upgrading homes for energy efficiency. There are several approaches used by field practitioners, but researchers have indicated that the test procedures in use are complex to implement and provide too many false positives. Field failures often mean that the house is not upgraded until after remediation or not at all, if not include in the program. In this report the PARR and NorthernSTAR DOE Building America Teams provide a simplified test procedure that is easier to implement and should produce fewer false positives. A survey of state weatherization agencies on combustion safety issues, details of a field data collection instrumentation package, summary of data collected over seven months, data analysis and results are included. The project provides several key results. State weatherization agencies do not generally track combustion safety failures, the data from those that do suggest that there is little actual evidence that combustion safety failures due to spillage from non-dryer exhaust are common and that only a very small number of homes are subject to the failures. The project team collected field data on 11 houses in 2015. Of these homes, two houses that demonstrated prolonged and excessive spillage were also the only two with venting systems out of compliance with the National Fuel Gas Code. The remaining homes experienced spillage that only occasionally extended beyond the first minute of operation. Combustion zone depressurization, outdoor temperature, and operation of individual fans all provide statistically significant predictors of spillage.

  3. Strobes: An oscillatory combustion

    NARCIS (Netherlands)

    Corbel, J.M.L.; Lingen, J.N.J. van; Zevenbergen, J.F.; Gijzeman, O.L.J.; Meijerink, A.

    2012-01-01

    Strobe compositions belong to the class of solid combustions. They are mixtures of powdered ingredients. When ignited, the combustion front evolves in an oscillatory fashion, and flashes of light are produced by intermittence. They have fascinated many scientists since their discovery at the beginni

  4. Strobes: An Oscillatory Combustion

    NARCIS (Netherlands)

    Corbel, J.M.L.; van Lingen, J.N.J.; Zevenbergen, J.F.; Gijzeman, O.L.J.; Meijerink, A.

    2012-01-01

    Strobe compositions belong to the class of solid combustions. They are mixtures of powdered ingredients. When ignited, the combustion front evolves in an oscillatory fashion, and flashes of light are produced by intermittence. They have fascinated many scientists since their discovery at the beginni

  5. Lectures on combustion theory

    Energy Technology Data Exchange (ETDEWEB)

    Burstein, S.Z.; Lax, P.D.; Sod, G.A. (eds.)

    1978-09-01

    Eleven lectures are presented on mathematical aspects of combustion: fluid dynamics, deflagrations and detonations, chemical kinetics, gas flows, combustion instability, flame spread above solids, spark ignition engines, burning rate of coal particles and hydrocarbon oxidation. Separate abstracts were prepared for three of the lectures. (DLC)

  6. Fifteenth combustion research conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-06-01

    The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers.

  7. Coal Combustion Science

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. (ed.); Fletcher, T.H.; Hurt, R.H.; Baxter, L.L. (Sandia National Labs., Livermore, CA (United States))

    1991-08-01

    The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. Specific tasks for this activity include: (1) coal devolatilization - the objective of this risk is to characterize the physical and chemical processes that constitute the early devolatilization phase of coal combustion as a function of coal type, heating rate, particle size and temperature, and gas phase temperature and oxidizer concentration; (2) coal char combustion -the objective of this task is to characterize the physical and chemical processes involved during coal char combustion as a function of coal type, particle size and temperature, and gas phase temperature and oxygen concentration; (3) fate of mineral matter during coal combustion - the objective of this task is to establish a quantitative understanding of the mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distribution of mineral species in the unreacted coal, and the local gas temperature and composition.

  8. Combustion of coffee husks

    Energy Technology Data Exchange (ETDEWEB)

    Saenger, M.; Hartge, E.-U.; Werther, J. [Technical Univ. Hamburg-Harburg, Chemical Engineering 1, Hamburg (Germany); Ogada, T.; Siagi, Z. [Moi Univ., Dept. of Production Engineering, Eldoret (Kenya)

    2001-05-01

    Combustion mechanisms of two types of coffee husks have been studied using single particle combustion techniques as well as combustion in a pilot-scale fluidized bed facility (FBC), 150 mm in diameter and 9 m high. Through measurements of weight-loss and particle temperatures, the processes of drying, devolatilization and combustion of coffee husks were studied. Axial temperature profiles in the FBC were also measured during stationary combustion conditions to analyse the location of volatile release and combustion as a function of fuel feeding mode. Finally the problems of ash sintering were analysed. The results showed that devolatilization of coffee husks (65-72% volatile matter, raw mass) starts at a low temperature range of 170-200degC and takes place rapidly. During fuel feeding using a non water-cooled system, pyrolysis of the husks took place in the feeder tube leading to blockage and non-uniform fuel flow. Measurements of axial temperature profiles showed that during under-bed feeding, the bed and freeboard temperatures were more or less the same, whereas for over-bed feeding, freeboard temperatures were much higher, indicating significant combustion of the volatiles in the freeboard. A major problem observed during the combustion of coffee husks was ash sintering and bed agglomeration. This is due to the low melting temperature of the ash, which is attributed to the high contents of K{sub 2}O (36-38%) of the coffee husks. (Author)

  9. Algorithmic Enhancements for Unsteady Aerodynamics and Combustion Applications

    Science.gov (United States)

    Venkateswaran, Sankaran; Olsen, Michael (Technical Monitor)

    2001-01-01

    Research in the FY01 focused on the analysis and development of enhanced algorithms for unsteady aerodynamics and chemically reacting flowfields. The research was performed in support of NASA Ames' efforts to improve the capabilities of the in-house computational fluid dynamics code, OVERFLOW. Specifically, the research was focused on the four areas: (1) investigation of stagnation region effects; (2) unsteady preconditioning dual-time procedures; (3) dissipation formulation for combustion; and (4) time-stepping methods for combustion.

  10. Internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Helmich, M.J.; Hoagland, M.C.; Hubbard, R.L.; Schaub, F.S.

    1981-12-22

    A method of combusting natural gas fuel in a two cycle, turbocharged internal combustion engine substantially reduces the production of nitrogen-oxygen emissions. An improved turbocharger design provides increased air charging pressure, produces a controlled lean air/fuel mixture and lowers peak combustion temperatures. A jet cell ignition device ensures uniform, reliable ignition of the lean air/fuel mixture under all operating conditions and the lean air/fuel mixture in turn encourages complete fuel combustion and provides excellent combustion characteristics with methane, ethane and heavier paraffinic hydrocarbon fuels. These structural modifications and adjustment of other operating parameters combine to reduce nitric oxide (NO) and nitrogen dioxide (NO/sub 2/) emissions by as much as 75% while effecting only a negligible increase in fuel consumption.

  11. Fuels and Combustion

    KAUST Repository

    Johansson, Bengt

    2016-08-17

    This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

  12. Assessment of Literature Related to Combustion Appliance Venting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Vi H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stratton, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-06-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is constrained by concerns about related impacts on the safety of naturally vented combustion appliances. Tighter housing units more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spillage. Several test methods purportedly assess the potential for depressurization-induced backdrafting and spillage, but these tests are not robustly reliable and repeatable predictors of venting performance, in part because they do not fully capture weather effects on venting performance. The purpose of this literature review is to investigate combustion safety diagnostics in existing codes, standards, and guidelines related to combustion appliances. This review summarizes existing combustion safety test methods, evaluations of these test methods, and also discusses research related to wind effects and the simulation of vent system performance. Current codes and standards related to combustion appliance installation provide little information on assessing backdrafting or spillage potential. A substantial amount of research has been conducted to assess combustion appliance backdrafting and spillage test methods, but primarily focuses on comparing short-term (stress) induced tests and monitoring results. Monitoring, typically performed over one week, indicated that combinations of environmental and house operation characteristics most conducive to combustion spillage were rare. Research, to an extent, has assessed existing combustion safety diagnostics for house depressurization, but the objectives of the diagnostics, both stress and monitoring, are not clearly defined. More research is also needed to quantify the frequency of test “failure” occurrence throughout the building stock and assess the statistical effects of weather (especially wind) on house depressurization and in turn on combustion appliance venting

  13. Thermodynamic Model of Aluminum Combustion in SDF Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, . L

    2006-06-19

    Thermodynamic states encountered during combustion of Aluminum powder in Shock-Dispersed-Fuel (SDF) explosions were analyzed with the Cheetah code. Results are displayed in the Le Chatelier diagram: the locus of states of specific internal energy versus temperature. Accuracy of the results was confirmed by comparing the fuel and products curves with the heats of detonation and combustion, and species composition as measured in bomb calorimeter experiments. Results were fit with analytic functions u = f(T) suitable for specifying the thermodynamic properties required for gas-dynamic models of combustion in explosions.

  14. Pressurized circulating fluidized bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez-Malebran, S.; Anglesea, W.T. [Fluent Europe Limited, Sheffield (United Kingdom)

    1998-12-31

    This report describes how the FLUENT computations fluid dynamics code has been provided with a granular (gas-solids), multiphase flow-modelling capability in order to simulate the operation of a circulating fluidized bed combustion chamber. The new multiphase module solves the conservation equations for each phase on an Eulerian basis and it currently enables gas phase reactions and interphase heat and momentum transfer to be modelled. Because of fundng restrictions, the module has not yet been provided with a general capability for modelling interphase mass transfer and therefore approximations have to be made when simulating coal combustion. Having developed the code and carried out basic testing, it has been used to simulate one set of conditions in the circulating fluidized bed combustion test facility operated by RWE Energie AG at Niederaussem Germany. Considering the simplifications made in this simulation, the level of agreement between the code results and the available measurements and observations is very encouraging. 18 refs., 5 figs., 2 tabs.

  15. CD8(+) T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension.

    Science.gov (United States)

    Liu, Yunmeng; Rafferty, Tonya M; Rhee, Sung W; Webber, Jessica S; Song, Li; Ko, Benjamin; Hoover, Robert S; He, Beixiang; Mu, Shengyu

    2017-01-09

    Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8(+) T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8(+) T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8(+) T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K(+) channel Kir4.1, and stimulation of the Cl(-) channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension.

  16. Addition by subtraction in coupled-cluster theory: a reconsideration of the CC and CI interface and the nCC hierarchy.

    Science.gov (United States)

    Bartlett, Rodney J; Musiał, Monika

    2006-11-28

    The nCC hierarchy of coupled-cluster approximations, where n guarantees exactness for n electrons and all products of n electrons are derived and applied to several illustrative problems. The condition of exactness for n=2 defines nCCSD=2CC, with nCCSDT=3CC and nCCSDTQ=4CC being exact for three and four electrons. To achieve this, the minimum number of diagrams is evaluated, which is less than in the corresponding CC model. For all practical purposes, nCC is also the proper definition of a size-extensive CI. 2CC is also an orbitally invariant coupled electron pair approximation. The numerical results of nCC are close to those for the full CC variant, and in some cases are closer to the full CI reference result. As 2CC is exact for separated electron pairs, it is the natural zeroth-order approximation for the correlation problem in molecules with other effects introduced as these units start to interact. The nCC hierarchy of approximations has all the attractive features of CC including its size extensivity, orbital invariance, and orbital insensitivity, but in a conceptually appealing form suited to bond breaking, while being computationally less demanding. Excited states from the equation of motion (EOM-2CC) are also reported, which show results frequently approaching those of EOM-CCSDT.

  17. CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension

    Science.gov (United States)

    Liu, Yunmeng; Rafferty, Tonya M.; Rhee, Sung W.; Webber, Jessica S.; Song, Li; Ko, Benjamin; Hoover, Robert S.; He, Beixiang; Mu, Shengyu

    2017-01-01

    Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8+ T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8+ T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8+ T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K+ channel Kir4.1, and stimulation of the Cl− channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension. PMID:28067240

  18. Combustion Engines Development Mixture Formation, Combustion, Emissions and Simulation

    CERN Document Server

    Schwarz, Christian; Teichmann, Rüdiger

    2012-01-01

    In the development of engines and vehicles it is nowadays standard practice to use commercially available computing programmes for simulation, not only of the transient reaction of vehicles or of the complete driveshaft, but also of the highly unsteady processes in the combustion chamber of an engine. Normally the source code is not available for these computing programmes and it takes too much time to study the respective specifications, so the users often do not have sufficient knowledge about the physical and chemical contents of the approaches that the programmes are based on. We have often been faced with this fact in talks to employees or in discussions during the presentation of results of simulation. Therefore it is our aim to point out different physical and chemical approaches and to show the possibilities and limits of the models used.

  19. Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

    Directory of Open Access Journals (Sweden)

    Jeremy M. Rawson

    2004-08-01

    Full Text Available The dithiadiazolyl radical p-NCC6F4C6F4CNSSN• (4 retains its monomericnature in the solid state with molecules linked together into chains via supramolecularCN···S interactions. Variable temperature magnetic studies on 4 show that it behaves as anear-ideal Curie paramagnet (|θ| less than 0.1 K, indicating negligible intermolecularexchange. The effective magnetic moment (1.78 μB is temperature independent and inexcellent agreement with the value expected for an S = 1⁄2 paramagnet with g = 2.01(1.74μB. The lack of exchange coupling between radicals is attributed to the absence ofsignificant orbital overlap between radical centres.

  20. Optimization of analysis best-estimate of a fuel element BWR with Code STAR-CCM+; Optimizacion del analisis best-estimate de un elemento combustible BWR con el codigo STAR-CCM+

    Energy Technology Data Exchange (ETDEWEB)

    Morgado Canada, E.; Concejal Barmejo, A.; Jimenez Varas, G.; Solar Martinez, A.

    2014-07-01

    The objective of the project is the evaluation of the code STAR-CCM +, as well as the establishment of guidelines and standardized procedures for the discretization of the area of study and the selection of physical models suitable for the simulation of BWR fuel. For this purpose several of BFBT experiments have simulated [1] provide a data base for the development of experiments for measuring distribution of fractions of holes to changes in power in order to find the most appropriate models for the simulation of the problem. (Author)

  1. Lateral hydraulic forces calculation on PWR fuel assemblies with computational fluid dynamics codes; Calculo de fuerzas laterales hidraulicas en elementos combustibles tipo PWR con codigos de dinamica de fluidos coputacional

    Energy Technology Data Exchange (ETDEWEB)

    Corpa Masa, R.; Jimenez Varas, G.; Moreno Garcia, B.

    2016-08-01

    To be able to simulate the behavior of nuclear fuel under operating conditions, it is required to include all the representative loads, including the lateral hydraulic forces which were not included traditionally because of the difficulty of calculating them in a reliable way. Thanks to the advance in CFD codes, now it is possible to assess them. This study calculates the local lateral hydraulic forces, caused by the contraction and expansion of the flow due to the bow of the surrounding fuel assemblies, on of fuel assembly under typical operating conditions from a three loop Westinghouse PWR reactor. (Author)

  2. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Clifford Smith

    2003-09-01

    Application and testing of the new combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this 12th quarterly report. In this quarter, continued validation and testing of the combustion LES code was performed for the DOE-SimVal combustor. Also, beta testing by six consortium members was performed for various burner and combustor configurations. A list of suggested code improvements by the beta testers was itemized. Work will continue in FY04. A conditional modification to the contract will be granted. The additional work will focus on modeling/analyzing the SimVal experiments.

  3. Regulation of NHE3, NKCC2, and NCC abundance in kidney during aldosterone escape phenomenon: role of NO.

    Science.gov (United States)

    Turban, Sharon; Wang, Xiao-Yan; Knepper, Mark A

    2003-11-01

    Escape from aldosterone-induced renal NaCl retention is an important homeostatic mechanism in pathophysiological states in which plasma aldosterone levels are inappropriately elevated, e.g., in primary aldosteronism. Our previous studies demonstrated that the escape process occurs largely as a result of a marked suppression of the abundance of the thiazide-sensitive Na-Cl cotransporter (NCC) of the distal convoluted tubule but have also demonstrated a paradoxical increase in the protein abundance of the apical Na/H exchanger of the proximal tubule (NHE3). In the present study, we confirmed the increase in NHE3 and also showed that a similar increase in NHE3 protein abundance occurs in escape from ANG II-mediated NaCl retention. To investigate the potential role of nitric oxide (NO) in the observed upregulation of NHE3, we repeated the aldosterone escape experiment with a superimposed infusion of a NO synthase inhibitor, NG-nitro-l-arginine methyl ester (l-NAME). l-NAME infusion abolished the increase in NHE3 protein abundance. Furthermore, in a different experiment, NO synthase inhibition uncovered an associated decrease in the abundance of the Na-K-2Cl cotransporter (NKCC2) of the thick ascending limb, not seen with simple aldosterone escape. However, NO synthase inhibition did not block the decrease in NCC abundance normally seen with aldosterone escape. Furthermore, l-NAME infusion in aldosterone-treated rats markedly decreased both NHE3 and NKCC2 protein abundance, without changes in the corresponding mRNA levels. We conclude that NHE3 and NKCC2 protein abundances in kidney are positively regulated by NO and that the increase in NHE3 abundance seen in the aldosterone escape phenomenon is NO dependent.

  4. Climate Change Projections for the 21st Century by the NCC/IAP T63 Model with SRES Scenarios

    Institute of Scientific and Technical Information of China (English)

    XU Ying; ZHAO Zongci; LUO Yong; GAO Xuejie

    2005-01-01

    The projections of climate change in the globe and East Asia by the NCC/IAP T63 model with the SRES A2 and A1B scenarios have been investigated in this paper. The results pointed out a global warming of 3.6℃/100 yr and 2.5℃/100 yr for A2 and A1B during the 21st century, respectively. The warming in high and middle latitudes will be more obvious than that in low latitudes, especially in the winter hemisphere.The warming of 5.1℃/100 yr for A2 and 3.6℃/100 yr for A1B over East Asia in the 21st century will be much higher than that in the globe. The global mean precipitation will increase by about 4.3%/100 yr for A2 and 3.4%/100 yr for A1B in the 21st century, respectively. The precipitation will increase in most parts of the low and high latitudes and decrease in some regions of the subtropical latitudes. The linear trends of the annual mean precipitation anomalies over East Asia will be 9.8%/100 yr for A2 and 5.2%/100 yr for A1B, respectively. The drier situations will occur over the northwestern and southeastern parts of East Asia.The changes of the annual mean temperature and precipitation in the globe for the 21st century by the NCC/IAP T63 model with SRES A2 and A1B scenarios are in agreement with a number of the model projections.

  5. Modification of the technical properties of Lactobacillus johnsonii NCC 533 by supplementing the growth medium with unsaturated fatty acids.

    Science.gov (United States)

    Muller, J A; Ross, R P; Sybesma, W F H; Fitzgerald, G F; Stanton, C

    2011-10-01

    The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 μg/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 μg/ml). Following acid exposure, significantly higher (P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical

  6. Perinatal maternal administration of Lactobacillus paracasei NCC 2461 prevents allergic inflammation in a mouse model of birch pollen allergy.

    Science.gov (United States)

    Schabussova, Irma; Hufnagl, Karin; Tang, Mimi L K; Hoflehner, Elisabeth; Wagner, Angelika; Loupal, Gerhard; Nutten, Sophie; Zuercher, Adrian; Mercenier, Annick; Wiedermann, Ursula

    2012-01-01

    The hygiene hypothesis implies that microbial agents including probiotic bacteria may modulate foetal/neonatal immune programming and hence offer effective strategies for primary allergy prevention; however their mechanisms of action are poorly understood. We investigated whether oral administration of Lactobacillus paracasei NCC 2461 to mothers during gestation/lactation can protect against airway inflammation in offspring in a mouse model of birch pollen allergy, and examined the immune mechanisms involved. BALB/c mice were treated daily with L. paracasei in drinking water or drinking water alone in the last week of gestation and during lactation. Their offspring were sensitized with recombinant Bet v 1, followed by aerosol challenge with birch pollen extract. Maternal exposure to L. paracasei prevented the development of airway inflammation in offspring, as demonstrated by attenuation of eosinophil influx in the lungs; reduction of IL-5 levels in bronchoalveolar lavage, and in lung and mediastinal lymph node cell cultures; and reduced peribronchial inflammatory infiltrate and mucus hypersecretion. While allergen-specific IgE and IgG antibody levels remained unchanged by the treatment, IL-4 and IL-5 production in spleen cell cultures were significantly reduced upon allergen stimulation in offspring of L. paracasei treated mice. Offspring of L. paracasei supplemented mothers had significantly reduced Bet v 1-specific as well as Concanavalin A-induced responses in spleen and mesenteric lymph node cell cultures, suggesting the modulation of both antigen-specific and mitogen-induced immune responses in offspring. These effects were associated with increased Foxp3 mRNA expression in the lungs and increased TGF-beta in serum. Our data show that in a mouse model of birch pollen allergy, perinatal administration of L. paracasei NCC 2461 to pregnant/lactating mothers protects against the development of airway inflammation in offspring by activating regulatory pathways

  7. Perinatal maternal administration of Lactobacillus paracasei NCC 2461 prevents allergic inflammation in a mouse model of birch pollen allergy.

    Directory of Open Access Journals (Sweden)

    Irma Schabussova

    Full Text Available BACKGROUND: The hygiene hypothesis implies that microbial agents including probiotic bacteria may modulate foetal/neonatal immune programming and hence offer effective strategies for primary allergy prevention; however their mechanisms of action are poorly understood. We investigated whether oral administration of Lactobacillus paracasei NCC 2461 to mothers during gestation/lactation can protect against airway inflammation in offspring in a mouse model of birch pollen allergy, and examined the immune mechanisms involved. METHODS: BALB/c mice were treated daily with L. paracasei in drinking water or drinking water alone in the last week of gestation and during lactation. Their offspring were sensitized with recombinant Bet v 1, followed by aerosol challenge with birch pollen extract. RESULTS: Maternal exposure to L. paracasei prevented the development of airway inflammation in offspring, as demonstrated by attenuation of eosinophil influx in the lungs; reduction of IL-5 levels in bronchoalveolar lavage, and in lung and mediastinal lymph node cell cultures; and reduced peribronchial inflammatory infiltrate and mucus hypersecretion. While allergen-specific IgE and IgG antibody levels remained unchanged by the treatment, IL-4 and IL-5 production in spleen cell cultures were significantly reduced upon allergen stimulation in offspring of L. paracasei treated mice. Offspring of L. paracasei supplemented mothers had significantly reduced Bet v 1-specific as well as Concanavalin A-induced responses in spleen and mesenteric lymph node cell cultures, suggesting the modulation of both antigen-specific and mitogen-induced immune responses in offspring. These effects were associated with increased Foxp3 mRNA expression in the lungs and increased TGF-beta in serum. CONCLUSION: Our data show that in a mouse model of birch pollen allergy, perinatal administration of L. paracasei NCC 2461 to pregnant/lactating mothers protects against the development of airway

  8. Numerical simulation of fuel sprays and combustion in a premixed lean diesel engine; Kihaku yokongo diesel kikan ni okeru nenryo funmu to nensho no suchi simulation

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, T.; Harada, A.; Sasaki, S.; Shimazaki, N.; Hashizume, T.; Akagawa, H.; Tsujimura, K.

    1997-10-01

    Fuel sprays and combustion in a direct injection Premixed lean Diesel Combustion (PREDIC) engine, which can make smokeless combustion with little NOx emission, is studied numerically. Numerical simulation was carried out by means of KIVA II based computer code with a combustion submodel. The combustion submodel describes the formation of combustible fuel vapor by turbulent mixing and four-step chemical reaction which includes low temperature oxidation. Comparison between computation and experiment shows qualitatively good agreement in terms of heat release rate and NO emission. Computational results indicate that the combustion is significantly influenced by fuel spray characteristics and injection timing to vary NO emission. 10 refs., 8 figs., 1 tab.

  9. Downregulation of NCC and NKCC2 cotransporters by kidney-specific WNK1 revealed by gene disruption and transgenic mouse models.

    Science.gov (United States)

    Liu, Zhen; Xie, Jian; Wu, Tao; Truong, Thao; Auchus, Richard J; Huang, Chou-Long

    2011-03-01

    WNK1 (with-no-lysine[K]-1) is a protein kinase of which mutations cause a familial hypertension and hyperkalemia syndrome known as pseudohypoaldosteronism type 2 (PHA2). Kidney-specific (KS) WNK1 is an alternatively spliced form of WNK1 kinase missing most of the kinase domain. KS-WNK1 downregulates the Na(+)-Cl(-) cotransporter NCC by antagonizing the effect of full-length WNK1 when expressed in Xenopus oocytes. The physiological role of KS-WNK1 in the regulation of NCC and potentially other Na(+) transporters in vivo is unknown. Here, we report that mice overexpressing KS-WNK1 in the kidney exhibited renal Na(+) wasting, elevated plasma levels of angiotensin II and aldosterone yet lower blood pressure relative to wild-type littermates. Immunofluorescent staining revealed reduced surface expression of total and phosphorylated NCC and the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 in the distal convoluted tubule and the thick ascending limb of Henle's loop, respectively. Conversely, mice with targeted deletion of exon 4A (the first exon for KS-WNK1) exhibited Na(+) retention, elevated blood pressure on a high-Na(+) diet and increased surface expression of total and phosphorylated NCC and NKCC2 in respective nephron segments. Thus, KS-WNK1 is a negative regulator of NCC and NKCC2 in vivo and plays an important role in the control of Na(+) homeostasis and blood pressure. These results have important implications to the pathogenesis of PHA2 with WNK1 mutations.

  10. Expression of renal distal tubule transporters TRPM6 and NCC in a rat model of cyclosporine nephrotoxicity and effect of EGF treatment.

    Science.gov (United States)

    Ledeganck, Kristien J; Boulet, Gaëlle A; Horvath, Caroline A; Vinckx, Marleen; Bogers, Johannes J; Van Den Bossche, Rita; Verpooten, Gert A; De Winter, Benedicte Y

    2011-09-01

    Renal magnesium (Mg(2+)) and sodium (Na(+)) loss are well-known side effects of cyclosporine (CsA) treatment in humans, but the underlying mechanisms still remain unclear. Recently, it was shown that epidermal growth factor (EGF) stimulates Mg(2+) reabsorption in the distal convoluted tubule (DCT) via TRPM6 (Thébault S, Alexander RT, Tiel Groenestege WM, Hoenderop JG, Bindels RJ. J Am Soc Nephrol 20: 78-85, 2009). In the DCT, the final adjustment of renal sodium excretion is regulated by the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC), which is activated by the renin-angiotensin-aldosterone system (RAAS). The aim of this study was to gain more insight into the molecular mechanisms of CsA-induced hypomagnesemia and hyponatremia. Therefore, the renal expression of TRPM6, TRPM7, EGF, EGF receptor, claudin-16, claudin-19, and the NCC, and the effect of the RAAS on NCC expression, were analyzed in vivo in a rat model of CsA nephrotoxicity. Also, the effect of EGF administration on these parameters was studied. CsA significantly decreased the renal expression of TRPM6, TRPM7, NCC, and EGF, but not that of claudin-16 and claudin-19. Serum aldosterone was significantly lower in CsA-treated rats. In control rats treated with EGF, an increased renal expression of TRPM6 together with a decreased fractional excretion of Mg(2+) (FE Mg(2+)) was demonstrated. EGF did not show this beneficial effect on TRPM6 and FE Mg(2+) in CsA-treated rats. These data suggest that CsA treatment affects Mg(2+) homeostasis via the downregulation of TRPM6 in the DCT. Furthermore, CsA downregulates the NCC in the DCT, associated with an inactivation of the RAAS, resulting in renal sodium loss.

  11. Paradoxical activation of the sodium chloride cotransporter (NCC) without hypertension in kidney deficient in a regulatory subunit of Na,K-ATPase, FXYD2.

    Science.gov (United States)

    Arystarkhova, Elena; Ralph, Donna L; Liu, Yi Bessie; Bouley, Richard; McDonough, Alicia A; Sweadner, Kathleen J

    2014-12-01

    Na,K-ATPase generates the driving force for sodium reabsorption in the kidney. Na,K-ATPase functional properties are regulated by small proteins belonging to the FXYD family. In kidney FXYD2 is the most abundant: it is an inhibitory subunit expressed in almost every nephron segment. Its absence should increase sodium pump activity and promote Na(+) retention, however, no obvious renal phenotype was detected in mice with global deletion of FXYD2 (Arystarkhova et al. 2013). Here, increased total cortical Na,K-ATPase activity was documented in the Fxyd2(-/-) mouse, without increased α1β1 subunit expression. We tested the hypothesis that adaptations occur in distal convoluted tubule (DCT), a major site of sodium adjustments. Na,K-ATPase immunoreactivity in DCT was unchanged, and there was no DCT hypoplasia. There was a marked activation of thiazide-sensitive sodium chloride cotransporter (NCC; Slc12a3) in DCT, predicted to increase Na(+) reabsorption in this segment. Specifically, NCC total increased 30% and NCC phosphorylated at T53 and S71, associated with activation, increased 4-6 fold. The phosphorylation of the closely related thick ascending limb (TAL) apical NKCC2 (Slc12a1) increased at least twofold. Abundance of the total and cleaved (activated) forms of ENaC α-subunit was not different between genotypes. Nonetheless, no elevation of blood pressure was evident despite the fact that NCC and NKCC2 are in states permissive for Na(+) retention. Activation of NCC and NKCC2 may reflect an intracellular linkage to elevated Na,K-ATPase activity or a compensatory response to Na(+) loss proximal to the TAL and DCT. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  12. Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S; Dibble, R; Flowers, D; Smith, J R; Westbrook, C K

    1999-07-19

    This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.

  13. Sandia Combustion Research: Technical review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

  14. Holographic codes

    CERN Document Server

    Latorre, Jose I

    2015-01-01

    There exists a remarkable four-qutrit state that carries absolute maximal entanglement in all its partitions. Employing this state, we construct a tensor network that delivers a holographic many body state, the H-code, where the physical properties of the boundary determine those of the bulk. This H-code is made of an even superposition of states whose relative Hamming distances are exponentially large with the size of the boundary. This property makes H-codes natural states for a quantum memory. H-codes exist on tori of definite sizes and get classified in three different sectors characterized by the sum of their qutrits on cycles wrapped through the boundaries of the system. We construct a parent Hamiltonian for the H-code which is highly non local and finally we compute the topological entanglement entropy of the H-code.

  15. Sharing code

    OpenAIRE

    Kubilius, Jonas

    2014-01-01

    Sharing code is becoming increasingly important in the wake of Open Science. In this review I describe and compare two popular code-sharing utilities, GitHub and Open Science Framework (OSF). GitHub is a mature, industry-standard tool but lacks focus towards researchers. In comparison, OSF offers a one-stop solution for researchers but a lot of functionality is still under development. I conclude by listing alternative lesser-known tools for code and materials sharing.

  16. Improving combustion efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Bulsari, A.; Wemberg, A.; Multas, A. [Nonlinear Solutions Oy (Finland)

    2009-06-15

    The paper describes how nonlinear models are used to improve the efficiency of coal combustion while keeping NOx and other emissions under desired limits in the Naantali 2 boiler of Fortum Power and Heat Oy. 16 refs., 6 figs.

  17. Fluidized coal combustion

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L.

    1979-01-01

    Fluidized-bed coal combustion process, in which pulverized coal and limestone are burned in presence of forced air, may lead to efficient, reliable boilers with low sulfur dioxide and nitrogen dioxide emissions.

  18. Modelling diesel combustion

    CERN Document Server

    Lakshminarayanan, P A; Shi, Yu; Reitz, Rolf D

    2010-01-01

    The underlying principles of combustion phenomena are presented here, providing the basis for quantitative evaluation. These phenomena - ignition delay, fuel air mixing, rate of release, etc. - are then modelled for greater understanding and applicability.

  19. TENORM: Coal Combustion Residuals

    Science.gov (United States)

    Burning coal in boilers to create steam for power generation and industrial applications produces a number of combustion residuals. Naturally radioactive materials that were in the coal mostly end up in fly ash, bottom ash and boiler slag.

  20. Scramjet Combustion Processes

    Science.gov (United States)

    2010-09-01

    plan for these flights is as follows: Scramjet Combustion Processes RTO-EN-AVT-185 11 - 21 HyShot 5 – A Free-Flying Hypersonic Glider HyShot...5 will be a hypersonic glider designed to fly at Mach 8. It will separate from its rocket booster in space and perform controlled manoeuvres as it...RTO-EN-AVT-185 11 - 1 Scramjet Combustion Processes Michael Smart and Ray Stalker Centre for Hypersonics The University of Queensland

  1. Sandia Combustion Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, S.C.; Palmer, R.E.; Montana, C.A. (eds.)

    1988-01-01

    During the late 1970s, in response to a national energy crisis, Sandia proposed to the US Department of Energy (DOE) a new, ambitious program in combustion research. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''user facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative-involving US inventories, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions several research projects which have been simulated by working groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship program, supported through the Office of Energy Research, has been instrumental in the success of some of these joint efforts. The remainder of this report presents results of calendar year 1988, separated thematically into eleven categories. Referred journal articles appearing in print during 1988 and selected other publications are included at the end of Section 11. Our traditional'' research activities--combustion chemistry, reacting flows, diagnostics, engine and coal combustion--have been supplemented by a new effort aimed at understanding combustion-related issues in the management of toxic and hazardous materials.

  2. METC Combustion Research Facility

    Energy Technology Data Exchange (ETDEWEB)

    Halow, J.S.; Maloney, D.J.; Richards, G.A.

    1993-11-01

    The objective of the Morgantown Energy Technology Center (METC) high pressure combustion facility is to provide a mid-scale facility for combustion and cleanup research to support DOE`s advanced gas turbine, pressurized, fluidized-bed combustion, and hot gas cleanup programs. The facility is intended to fill a gap between lab scale facilities typical of universities and large scale combustion/turbine test facilities typical of turbine manufacturers. The facility is now available to industry and university partners through cooperative programs with METC. High pressure combustion research is also important to other DOE programs. Integrated gasification combined cycle (IGCC) systems and second-generation, pressurized, fluidized-bed combustion (PFBC) systems use gas turbines/electric generators as primary power generators. The turbine combustors play an important role in achieving high efficiency and low emissions in these novel systems. These systems use a coal-derived fuel gas as fuel for the turbine combustor. The METC facility is designed to support coal fuel gas-fired combustors as well as the natural gas fired combustor used in the advanced turbine program.

  3. A combustion model for studying the effects of ideal gas properties on jet noise

    Science.gov (United States)

    Jacobs, Jerin; Tinney, Charles

    2016-11-01

    A theoretical combustion model is developed to simulate the influence of ideal gas effects on various aeroacoustic parameters over a range of equivalence ratios. The motivation is to narrow the gap between laboratory and full-scale jet noise testing. The combustion model is used to model propane combustion in air and kerosene combustion in air. Gas properties from the combustion model are compared to real lab data acquired at the National Center for Physical Acoustics at the University of Mississippi as well as outputs from NASA's Chemical Equilibrium Analysis code. Different jet properties are then studied over a range of equivalence ratios and pressure ratios for propane combustion in air, kerosene combustion in air and heated air. The findings reveal negligible differences between the three constituents where the density and sound speed ratios are concerned. Albeit, the area ratio required for perfectly expanded flow is shown to be more sensitive to gas properties, relative to changes in the temperature ratio.

  4. Effect of CO Combustion Promoters on Combustion Air Partition in FCC under Nearly Complete Combustion

    Institute of Scientific and Technical Information of China (English)

    王锐; 罗雄麟; 许锋

    2014-01-01

    With CO combustion promoters, the role of combustion air flow rate for concerns of economics and control is important. The combustion air is conceptually divided to three parts:the air consumed by coke burning, the air consumed by CO combustion and the air unreacted. A mathematical model of a fluid catalytic cracking (FCC) unit, which includes a quantitative correlation of CO heterogeneous combustion and the amount of CO combustion promoters, is introduced to investigate the effects of promoters on the three parts of combustion air. The results show that the air consumed by coke burning is almost linear to combustion air flow rate, while the air consumed by CO combustion promoters tends to saturate as combustion air flow rate increases, indicating that higher air flow rate can only be used as a manipulated variable to control the oxygen content for an economic concern.

  5. Genome-wide and Function Analysis of the Secretory Proteins of Bifidobacterium longum NCC2705%长双歧杆菌NCC2705分泌蛋白的全基因组预测和功能分析

    Institute of Scientific and Technical Information of China (English)

    朱德全; 王茗悦; 栗金柳; 孟祥晨; 程广东; 岳丽红; 王长平; 薛勇

    2016-01-01

    With the genome proteins sequences of Bifidobacterium longum FNCC2705 as study objects,SignalP 4.0,LipoP,TMHMM 2.0 software were used to analyze the secretory proteins and types of signal peptide.Function of secretory proteins was also analyzed by COG ( Cluster of Or-thologous Groups of proteins) database.Results showed a total of 37 secretion proteins through Sec pathway which included 27 secreted proteins recognized by SPaseⅠand 10 secreted proteins recognized by SPaseⅡ.Maximum length of their signal peptide is 52 aa and minimum length is 10 aa respectively.The functions of Bifidobacterium secretory protein showed there were many hypothetical proteins.Secretory protein with annotation of COG functions were mainly involved in amino acid transport and metabolism,carbohydrate transport and metabolism,inorganic ion transport and metabolism,etc..The functions of these secretory proteins can help bifidobacterium adapt to its host environment.%以长双歧杆菌NCC2705基因组序列为研究对象,使用SignalP 4.0、LipoP、TMHMM 2.0软件分析该基因组中的分泌蛋白及其信号肽的类型,同时采用COG ( Cluster of Orthologous Groups of proteins)功能数据库对预测的分泌蛋白进行功能注释和聚类分析。结果表明,长双岐杆菌NCC2705中共有37个Sec途径分泌蛋白,其中Sec途径分泌蛋白包括27个被I型( SPaseⅠ)信号肽酶和10个Ⅱ型信号肽酶( SpaseII)识别的蛋白,Sec 途径分泌蛋白信号肽长度最多的有52个氨基酸,最少的有10个氨基酸。分泌蛋白的功能分析表明,该菌株分泌蛋白中含有大部分的假定蛋白,主要参与氨基酸代谢与转运、碳水化合物代谢转运,无机盐离子代谢转运,细胞壁和细胞膜生物合成的功能有关。

  6. Transformations of inorganic coal constituents in combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. (ed.); Srinivasachar, S.; Wilemski, G.; Boni, A.A. (PSI Technology Co., Andover, MA (United States)); Kang, Shim-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Peterson, T.W.; Wendt, O.L.; Gallagher, N.B.; Bool, L. (Arizona Univ., Tucson, AZ (United States)); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. (Kentucky Univ., Lexington

    1992-11-01

    This report contains the computer codes developed for the coal combustion project. In Subsection B.1 the FORTRAN code developed for the percolative fragmentation model (or the discrete model, since a char is expressed as a collection of discrete elements in a discrete space) is presented. In Subsection B.2 the code for the continuum model (thus named because mineral inclusions are distributed in a continuum space) is presented. A stereological model code developed to obtain the pore size distribution from a two-dimensional data is presented in Subsection B.3.

  7. Speaking Code

    DEFF Research Database (Denmark)

    Cox, Geoff

    Speaking Code begins by invoking the “Hello World” convention used by programmers when learning a new language, helping to establish the interplay of text and code that runs through the book. Interweaving the voice of critical writing from the humanities with the tradition of computing and software...

  8. Polar Codes

    Science.gov (United States)

    2014-12-01

    QPSK Gaussian channels . .......................................................................... 39 vi 1. INTRODUCTION Forward error correction (FEC...Capacity of BSC. 7 Figure 5. Capacity of AWGN channel . 8 4. INTRODUCTION TO POLAR CODES Polar codes were introduced by E. Arikan in [1]. This paper...Under authority of C. A. Wilgenbusch, Head ISR Division EXECUTIVE SUMMARY This report describes the results of the project “More reliable wireless

  9. MELCOR computer code manuals

    Energy Technology Data Exchange (ETDEWEB)

    Summers, R.M.; Cole, R.K. Jr.; Smith, R.C.; Stuart, D.S.; Thompson, S.L. [Sandia National Labs., Albuquerque, NM (United States); Hodge, S.A.; Hyman, C.R.; Sanders, R.L. [Oak Ridge National Lab., TN (United States)

    1995-03-01

    MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor nuclear power plants. MELCOR is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission as a second-generation plant risk assessment tool and the successor to the Source Term Code Package. A broad spectrum of severe accident phenomena in both boiling and pressurized water reactors is treated in MELCOR in a unified framework. These include: thermal-hydraulic response in the reactor coolant system, reactor cavity, containment, and confinement buildings; core heatup, degradation, and relocation; core-concrete attack; hydrogen production, transport, and combustion; fission product release and transport; and the impact of engineered safety features on thermal-hydraulic and radionuclide behavior. Current uses of MELCOR include estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications. This publication of the MELCOR computer code manuals corresponds to MELCOR 1.8.3, released to users in August, 1994. Volume 1 contains a primer that describes MELCOR`s phenomenological scope, organization (by package), and documentation. The remainder of Volume 1 contains the MELCOR Users Guides, which provide the input instructions and guidelines for each package. Volume 2 contains the MELCOR Reference Manuals, which describe the phenomenological models that have been implemented in each package.

  10. Modelling and simulation of wood chip combustion in a hot air generator system

    National Research Council Canada - National Science Library

    Rajika, J K. A. T; Narayana, Mahinsasa

    2016-01-01

    .... Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool...

  11. Internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.J.

    1986-06-03

    A variable power internal combustion engine is described which consists of: a separate air compressor for receiving and compressing a flow of air to a given pressure, the compressor having an inlet valve introducing a flow of air into the compressor and an outlet valve for exhausting compressed air out of the compressor into a compressed air storage means, at least one expander having a cylinder, a cylinder head closing an end of the cylinder, a piston reciprocally mounted in the cylinder for movement away from the cylinder head in a power stroke from an initial position defining a combustion chamber within the cylinder between the cylinder head and the piston, the compressed air storage means receiving the pressurized flow of air from the compressor and being of a volume adequate to provide compressed air in the combustion chamber essentially at the given pressure essentially over the power output of the engine, means for introducing an amount of combustible fuel in the compressed charge to be present with compressed air in the combustion chamber and providing combustion of the amount of fuel in the cylinder with the inlet and exhaust valves closed, cam shaft means in contact with the piston for absorbing and storing the energy of the power stroke of the piston and controlling movement of the piston within the cylinder during the exhaust stroke; the means for varying the volume of the combustion chamber being controlled in accordance with power requirements to provide variable power output and improved efficiency of the engine at power outputs reduced relative to a given design power output of the engine by providing a variable expansion ratio of a minimum of at least about 30 to 1 at the given design power output and higher with reduced power output.

  12. Qualification of the Darwin code for the studies of the fuel cycle relative to the boiling water reactors; Qualification du formulaire Darwin pour les etudes du cycle du combustible pour les reacteurs a eau bouillante

    Energy Technology Data Exchange (ETDEWEB)

    Allais, V

    1998-03-01

    This thesis was carried out in the framework of fuel cycles studies in partnership with COGEMA; the aim is to determine physics parameters characterising Boiling Reactor Assemblies. Those reactors Firstly distinguish themselves from Pressurised Water Reactor by the boiling of the moderator in the core and secondary by the strong neutronics heterogeneity due to complex design. The diphasic mixture formed is characterised by the void fraction parameter. The loss of information, and neutronic studies characteristics of Boiling Water Reactors led us to make preliminary studies having in view to quantify the void fraction impact on the isotopics evolution. Studies on neutronics influence of assemblies and control rods from the immediate environment allows to define the cluster size to describe. The radial description optimisation with APOLLO-2 is necessary to improve the calculation performance and to reduce the errors coming from the modelization. The following points were studied: pellet radial discretization, clustering of cells characterized by a similar behaviour, options in flux spatial calculation (interface current formalism), self-shielding optimisation (specific to each isotopes). The three dimensional modelization with CRONOS-2 and the simplified accounting of the thermohydraulics / neutronics coupling done by a procedure developed and written during this thesis, allow an evaluation of axial distribution of void fraction, power and burn-up during the irradiation. The comparison with experimental analytic results of complete assembly and pin samples dissolutions allows the qualification of this procedure and confirms the necessity to take into account the void fraction axial variation during the evolution. The application of an automatic coupling with the DARWIN cycle code will allow a precise burnup calculation to be utilized in an industrial procedure. (author)

  13. CFD Investigation into Diesel PCCI Combustion with Optimized Fuel Injection

    Directory of Open Access Journals (Sweden)

    Lipeng Lu

    2011-03-01

    Full Text Available A multi-pulse injection strategy for premixed charge compression ignition (PCCI combustion was investigated in a four-valve, direct-injection diesel engine by a computational fluid dynamics (CFD simulation using KIVA-3V code coupled with detailed chemistry. The effects of fuel splitting proportion, injection timing, spray angles, and injection velocity were examined. The mixing process and formation of soot and nitrogen oxide (NOx emissions were investigated as the focus of the research. The results show that the fuel splitting proportion and the injection timing impacted the combustion and emissions significantly due to the considerable changes of the mixing process and fuel distribution in the cylinder. While the spray, inclusion angle and injection velocity at the injector exit, can be adjusted to improve mixing, combustion and emissions, appropriate injection timing and fuel splitting proportion must be jointly considered for optimum combustion performance.

  14. Combustible structural composites and methods of forming combustible structural composites

    Science.gov (United States)

    Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D; Swank, William D.

    2011-08-30

    Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

  15. The Role of Epithelial Sodium Channel ENaC and the Apical Cl-/HCO3- Exchanger Pendrin in Compensatory Salt Reabsorption in the Setting of Na-Cl Cotransporter (NCC) Inactivation.

    Science.gov (United States)

    Patel-Chamberlin, Mina; Varasteh Kia, Mujan; Xu, Jie; Barone, Sharon; Zahedi, Kamyar; Soleimani, Manoocher

    2016-01-01

    The absence of NCC does not cause significant salt wasting in NCC deficient mice under basal conditions. We hypothesized that ENaC and pendrin play important roles in compensatory salt absorption in the setting of NCC inactivation, and their inhibition and/or downregulation can cause significant salt wasting in NCC KO mice. WT and NCC KO mice were treated with a daily injection of either amiloride, an inhibitor of ENaC, or acetazolamide (ACTZ), a blocker of salt and bicarbonate reabsorption in the proximal tubule and an inhibitor of carbonic anhydrases in proximal tubule and intercalated cells, or a combination of acetazolamide plus amiloride for defined durations. Animals were subjected to daily balance studies. At the end of treatment, kidneys were harvested and examined. Blood samples were collected for electrolytes and acid base analysis. Amiloride injection significantly increased the urine output (UO) in NCC KO mice (from 1.3 ml/day before to 2.5 ml/day after amiloride, p0.05). The increase in UO in NCC KO mice was associated with a significant increase in sodium excretion (from 0.25 mmol/24 hrs at baseline to 0.35 mmol/24 hrs after amiloride injection, p80% reduction of kidney pendrin expression in both WT and NCC KO mice. However, ACTZ treatment noticeably increased urine output and salt excretion only in NCC KO mice (with urine output increasing from a baseline of 1.1 ml/day to 2.3 ml/day and sodium excretion increasing from 0.22 mmole/day before to 0.31 mmole/day after ACTZ) in NCC KO mice; both parameters were significantly higher than in WT mice. Western blot analysis demonstrated significant enhancement in ENaC expression in medulla and cortex of NCC KO and WT mice in response to ACTZ injection for 6 days, and treatment with amiloride in ACTZ-pretreated mice caused a robust increase in salt excretion in both NCC KO and WT mice. Pendrin KO mice did not display a significant increase in urine output or salt excretion after treatment with amiloride or

  16. Combustion and regulation; Combustion et reglementation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This conference was organized after the publication of the French by-law no 2010 relative to combustion installations and to the abatement of atmospheric pollution. Five topics were discussed during the conference: the new regulations, their content, innovations and modalities of application; the means of energy suppliers to face the new provisions and their schedule; the manufacturers proposals for existing installations and the new equipments; the administration control; and the impact of the new measures on exploitation and engineering. Twenty papers and 2 journal articles are reported in these proceedings. (J.S.)

  17. Randomised double-blind placebo-controlled study of the effect of Lactobacillus paracasei NCC 2461 on skin reactivity.

    Science.gov (United States)

    Gueniche, A; Philippe, D; Bastien, P; Reuteler, G; Blum, S; Castiel-Higounenc, I; Breton, L; Benyacoub, J

    2014-06-01

    In recent decades, the prevalence of subjects with reactive skin has considerably increased in industrialised countries. 50% of women and 30% of men report cutaneous discomfort classified under reactive/sensitive skin. Several topical approaches have been proposed, in particular through improvement of galenic forms or protection of epidermal surface. We propose to act differently, deeply from inside the body via an innovative nutritional approach. To this purpose, Lactobacillus paracasei NCC 2461 (ST11) was selected because of its specific beneficial skin properties discovered in in vitro studies, i.e. diminution of neurogenic inflammation and promotion of the recovery of skin barrier function. We designed a randomised double-blind placebo-controlled clinical study with a two-month supplementation in two female treatment groups (n=32 per group). A capsaicin test was performed to monitor the time course of skin sensitivity. Moreover, transepidermal water loss was assessed to analyse the rate of skin barrier function recovery; dryness of the leg and roughness of the cheeks was investigated by a dermatologist as well as by self-assessment. The results of the present clinical trial show that oral supplementation with the probiotic decreases skin sensitivity and increases the rate of barrier function recovery. Thus, the data provide evidence that daily intake of ST11 could improve reactive skin condition.

  18. KCNJ10 determines the expression of the apical Na-Cl cotransporter (NCC) in the early distal convoluted tubule (DCT1).

    Science.gov (United States)

    Zhang, Chengbiao; Wang, Lijun; Zhang, Junhui; Su, Xiao-Tong; Lin, Dao-Hong; Scholl, Ute I; Giebisch, Gerhard; Lifton, Richard P; Wang, Wen-Hui

    2014-08-12

    The renal phenotype induced by loss-of-function mutations of inwardly rectifying potassium channel (Kir), Kcnj10 (Kir4.1), includes salt wasting, hypomagnesemia, metabolic alkalosis and hypokalemia. However, the mechanism by which Kir.4.1 mutations cause the tubulopathy is not completely understood. Here we demonstrate that Kcnj10 is a main contributor to the basolateral K conductance in the early distal convoluted tubule (DCT1) and determines the expression of the apical Na-Cl cotransporter (NCC) in the DCT. Immunostaining demonstrated Kcnj10 and Kcnj16 were expressed in the basolateral membrane of DCT, and patch-clamp studies detected a 40-pS K channel in the basolateral membrane of the DCT1 of p8/p10 wild-type Kcnj10(+/+) mice (WT). This 40-pS K channel is absent in homozygous Kcnj10(-/-) (knockout) mice. The disruption of Kcnj10 almost completely eliminated the basolateral K conductance and decreased the negativity of the cell membrane potential in DCT1. Moreover, the lack of Kcnj10 decreased the basolateral Cl conductance, inhibited the expression of Ste20-related proline-alanine-rich kinase and diminished the apical NCC expression in DCT. We conclude that Kcnj10 plays a dominant role in determining the basolateral K conductance and membrane potential of DCT1 and that the basolateral K channel activity in the DCT determines the apical NCC expression possibly through a Ste20-related proline-alanine-rich kinase-dependent mechanism.

  19. Research on Spray, Combustion and Emission Characteristics for DI Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To improve the combustion chamber shape that can decrease the directed injection (DI) diesel emission, the theories of DI diesel spray, combustion and pollutant formation model are analysed and implemented based on the CFD code FIRE. Results show that the chamber with contracting orifice can get stronger squish swirl intensity. The results of the verification studies show a good accordance with the measurements and reveal that the individual processes of spray evolution, combustion and pollutant formation are well captured in FIRE. Finally, based on the analyzing and comparing of the calculation results of different chambers, a combustion chamber of contracting orifice geometry with lower emission is proposed.

  20. Studies in combustion dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Koszykowski, M.L. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to develop a fundamental understanding and a quantitative predictive capability in combustion modeling. A large part of the understanding of the chemistry of combustion processes comes from {open_quotes}chemical kinetic modeling.{close_quotes} However, successful modeling is not an isolated activity. It necessarily involves the integration of methods and results from several diverse disciplines and activities including theoretical chemistry, elementary reaction kinetics, fluid mechanics and computational science. Recently the authors have developed and utilized new tools for parallel processing to implement the first numerical model of a turbulent diffusion flame including a {open_quotes}full{close_quotes} chemical mechanism.

  1. Alcohol combustion chemistry

    KAUST Repository

    Sarathy, Mani

    2014-10-01

    Alternative transportation fuels, preferably from renewable sources, include alcohols with up to five or even more carbon atoms. They are considered promising because they can be derived from biological matter via established and new processes. In addition, many of their physical-chemical properties are compatible with the requirements of modern engines, which make them attractive either as replacements for fossil fuels or as fuel additives. Indeed, alcohol fuels have been used since the early years of automobile production, particularly in Brazil, where ethanol has a long history of use as an automobile fuel. Recently, increasing attention has been paid to the use of non-petroleum-based fuels made from biological sources, including alcohols (predominantly ethanol), as important liquid biofuels. Today, the ethanol fuel that is offered in the market is mainly made from sugar cane or corn. Its production as a first-generation biofuel, especially in North America, has been associated with publicly discussed drawbacks, such as reduction in the food supply, need for fertilization, extensive water usage, and other ecological concerns. More environmentally friendly processes are being considered to produce alcohols from inedible plants or plant parts on wasteland. While biofuel production and its use (especially ethanol and biodiesel) in internal combustion engines have been the focus of several recent reviews, a dedicated overview and summary of research on alcohol combustion chemistry is still lacking. Besides ethanol, many linear and branched members of the alcohol family, from methanol to hexanols, have been studied, with a particular emphasis on butanols. These fuels and their combustion properties, including their ignition, flame propagation, and extinction characteristics, their pyrolysis and oxidation reactions, and their potential to produce pollutant emissions have been intensively investigated in dedicated experiments on the laboratory and the engine scale

  2. Radiative Augmented Combustion.

    Science.gov (United States)

    1985-08-12

    86-0085 In 00I to RADIATIVE AUGMENTED COMBUSTION MOSHE LAVID M.L. ENERGIA , INC. P.O. BOX 1468 1 PRINCETON, NEW JERSEY 08542 AUGUST 1985 *.. plo...Combustion conducted at M.L. ENERGIA . It is funded by the Air Force Office of Scientific Research under Contract No. F49620-83-C-0133, with Dr. J.M...reported. It covers the second year of the contract, from July 15, 1984 through July 14, 1985. The work was performed at ENERGIA , Princeton, New Jersey

  3. Transition nozzle combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won-Wook; McMahan, Kevin Weston; Maldonado, Jaime Javier

    2016-11-29

    The present application provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle extending from the head end to the aft end, and an impingement sleeve surrounding the transition nozzle. The impingement sleeve may define a first cavity in communication with the head end for a first portion of the cooling flow and a second cavity in communication with the aft end for a second portion of the cooling flow. The transition nozzle may include a number of cooling holes thereon in communication with the second portion of the cooling flow.

  4. Toxicology of Biodiesel Combustion products

    Science.gov (United States)

    1. Introduction The toxicology of combusted biodiesel is an emerging field. Much of the current knowledge about biological responses and health effects stems from studies of exposures to other fuel sources (typically petroleum diesel, gasoline, and wood) incompletely combusted. ...

  5. Evaluation of reduced chemical kinetic mechanisms used for modeling mild combustion for natural gas

    Directory of Open Access Journals (Sweden)

    Hamdi Mohamed

    2009-01-01

    Full Text Available A numerical and parametric study was performed to evaluate the potential of reduced chemistry mechanisms to model natural gas chemistry including NOx chemistry under mild combustion mode. Two reduced mechanisms, 5-step and 9-step, were tested against the GRI-Mech3.0 by comparing key species, such as NOx, CO2 and CO, and gas temperature predictions in idealized reactors codes under mild combustion conditions. It is thus concluded that the 9-step mechanism appears to be a promising reduced mechanism that can be used in multi-dimensional codes for modeling mild combustion of natural gas.

  6. Speech coding

    Energy Technology Data Exchange (ETDEWEB)

    Ravishankar, C., Hughes Network Systems, Germantown, MD

    1998-05-08

    Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

  7. Experimental combustion an introduction

    CERN Document Server

    Mishra, D P

    2014-01-01

    ""… other books available in this area do not cover the detailed topics covered here. Energy and combustion is a hot issue. It is expected to be even hotter with more demand in this area as we search for cleaner methods of energy conversion from chemical to thermal energy.""-Ashwani K. Gupta, Department of Mechanical Engineering, University of Maryland, College Park, USA

  8. Coal combustion research

    Energy Technology Data Exchange (ETDEWEB)

    Daw, C.S.

    1996-06-01

    This section describes research and development related to coal combustion being performed for the Fossil Energy Program under the direction of the Morgantown Energy Technology Center. The key activity involves the application of chaos theory for the diagnosis and control of fossil energy processes.

  9. Optical Tomography in Combustion

    DEFF Research Database (Denmark)

    Evseev, Vadim

    . JQSRT 113 (2012) 2222, 10.1016/j.jqsrt.2012.07.015] included in the PhD thesis as an attachment. The knowledge and experience gained in the PhD project is the first important step towards introducing the advanced optical tomography methods of combustion diagnostics developed in the project to future...

  10. Combustion Models in Finance

    CERN Document Server

    Tannous, C

    2001-01-01

    Combustion reaction kinetics models are used for the description of a special class of bursty Financial Time Series. The small number of parameters they depend upon enable financial analysts to predict the time as well as the magnitude of the jump of the value of the portfolio. Several Financial Time Series are analysed within this framework and applications are given.

  11. Flameless Combustion Workshop

    Science.gov (United States)

    2005-09-20

    operating hours, to produce low emission levels of NOx, CO and UHC . Gas turbine combustion stability has increasingly become a crucial design issue as...achieved proved: "* Safe and reliable operation ofgas turbine combustors "* Low emissions of NO., CO and UHC These results have clear economically

  12. Speaking Code

    DEFF Research Database (Denmark)

    Cox, Geoff

    ; alternatives to mainstream development, from performances of the live-coding scene to the organizational forms of commons-based peer production; the democratic promise of social media and their paradoxical role in suppressing political expression; and the market’s emptying out of possibilities for free...... development, Speaking Code unfolds an argument to undermine the distinctions between criticism and practice, and to emphasize the aesthetic and political aspects of software studies. Not reducible to its functional aspects, program code mirrors the instability inherent in the relationship of speech...... expression in the public realm. The book’s line of argument defends language against its invasion by economics, arguing that speech continues to underscore the human condition, however paradoxical this may seem in an era of pervasive computing....

  13. Effects of combustible stacking in large compartments

    DEFF Research Database (Denmark)

    Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco

    2013-01-01

    of non uniform distribution of the combustible materials and fire propagation. These aspects are discussed in this paper with reference to an industrial steel building, taken as case study. Fires triggered by the burning of wooden pallets stored in the premises have been investigated with respect...... to different stacking configurations of the pallets with the avail of a CFD code. The results in term of temperatures of the hot gasses and of the steel elements composing the structural system are compared with simplified analytical model of localized and post-flashover fires, with the aim of highlighting...

  14. External combustion wankel engine for solar applications

    Energy Technology Data Exchange (ETDEWEB)

    Kovarsky, N.; Kaftori, D.; Gamzon, E.; Dgani, E. [Silver Arrow (Israel)

    1999-03-01

    An External Combustion Wankel Engine (ECWE), intended for use in a dish-engine solar power plant is discussed. The engine operates in a Brayton cycle using a gaseous working fluid, which is heated outside of the engine by concentrated solar radiation or fossil fuel. A computer simulation code that models the ECWE's operation and performance has been developed The program takes into account all of the engine's characteristics, subsystems and operating conditions. In the present work, the advantages and features of ECWE are considered in detail, together with simulation results of its performance. (authors)

  15. Theoretical studies of nonadiabatic and spin-forbidden processes: Investigations of the reactions and spectroscopy of radical species relevant to combustion reactions and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Yarkony, D.R. [Johns Hopkins Univ., Baltimore, MD (United States)

    1993-12-01

    This research program focusses on studies of spin-forbidden and electronically nonadiabatic processes involving radical species relevant to combustion reactions and combustion diagnostics. To study the electronic structure aspects of these processes a unique and powerful system of electronic structure programs, developed over the past nine years, the BROOKLYN codes, is employed. These programs enable the authors to address questions basic to the understanding of elementary combustion processes not tractable using more standard quantum chemistry codes.

  16. Multidimensional modeling of Dimethyl Ether(DME) spray combustion in DI diesel engine

    Institute of Scientific and Technical Information of China (English)

    WEN Hua; LIU Yong-chang; WEI Ming-rui; ZHANG Yu-sheng

    2005-01-01

    In the present study a modified CFD code KIVA3V was used to simulate the spray combustion in a small DI diesel engine fueled with DME. The improved spray models consider more spray phenomena such as cavitation flow in nozzle hole, jet atomization, droplet second breakup and spray wall interaction. Otherwise, a reduced DME reaction mechanism is implemented in the combustion model, and a new turbulent combustion model-Partial Stirred Reactor (PaSR) model is selected to simulate the spray combustion process, the effects of turbulent mixing on the reaction rate are considered. The results of engine modeling based on those models agreed well with the experimental measurements. Study of temperature fields variation and particle traces in the combustion chamber revealed that the engine combustion system originally used for diesel fuel must be optimized for DME.

  17. Pulverized coal torch combustion in a furnace with plasma-coal system

    Science.gov (United States)

    Messerle, V. E.; Ustimenko, A. B.; Askarova, A. S.; Nagibin, A. O.

    2010-09-01

    Combustion of a pulverized coal torch has been numerically simulated on the basis of the equations of multicomponent turbulent two-phase flows. The results of three-dimensional simulation of conventional and plasma activated coal combustion in a furnace are presented. Computer code Cinar ICE was verified at coal combustion in the experimental furnace with thermal power of 3 MW that was equipped with plasma-fuel system. Operation of the furnace has been studied at the conventional combustion mode and with plasma activation of coal combustion. Influence of plasma activation of combustion on thermotechnical characteristics of the torch and decrease of carbon loss and nitrogen oxides concentration at the furnace outlet has been revealed.

  18. Combustion calorimetry experimental chemical thermodynamics

    CERN Document Server

    Sunner, Stig

    1979-01-01

    Combustion Calorimetry deals with expertise knowledge concerning the calorimetry of combustion reactions of an element or compound. After defining the use of units and physical constants, the book discusses the basic principles of combustion calorimetry and the various instruments and calorimeters used in the experiments to measure operations concerning temperatures and its time variations. One paper discusses the theory and design criteria of combustion calorimeter calibration. Another paper discusses the results obtained from a combustion calorimeter after it has measured the energy or entha

  19. Modelling of CWS combustion process

    Science.gov (United States)

    Rybenko, I. A.; Ermakova, L. A.

    2016-10-01

    The paper considers the combustion process of coal water slurry (CWS) drops. The physico-chemical process scheme consisting of several independent parallel-sequential stages is offered. This scheme of drops combustion process is proved by the particle size distribution test and research stereomicroscopic analysis of combustion products. The results of mathematical modelling and optimization of stationary regimes of CWS combustion are provided. During modeling the problem of defining possible equilibrium composition of products, which can be obtained as a result of CWS combustion processes at different temperatures, is solved.

  20. The Aster code; Code Aster

    Energy Technology Data Exchange (ETDEWEB)

    Delbecq, J.M

    1999-07-01

    The Aster code is a 2D or 3D finite-element calculation code for structures developed by the R and D direction of Electricite de France (EdF). This dossier presents a complete overview of the characteristics and uses of the Aster code: introduction of version 4; the context of Aster (organisation of the code development, versions, systems and interfaces, development tools, quality assurance, independent validation); static mechanics (linear thermo-elasticity, Euler buckling, cables, Zarka-Casier method); non-linear mechanics (materials behaviour, big deformations, specific loads, unloading and loss of load proportionality indicators, global algorithm, contact and friction); rupture mechanics (G energy restitution level, restitution level in thermo-elasto-plasticity, 3D local energy restitution level, KI and KII stress intensity factors, calculation of limit loads for structures), specific treatments (fatigue, rupture, wear, error estimation); meshes and models (mesh generation, modeling, loads and boundary conditions, links between different modeling processes, resolution of linear systems, display of results etc..); vibration mechanics (modal and harmonic analysis, dynamics with shocks, direct transient dynamics, seismic analysis and aleatory dynamics, non-linear dynamics, dynamical sub-structuring); fluid-structure interactions (internal acoustics, mass, rigidity and damping); linear and non-linear thermal analysis; steels and metal industry (structure transformations); coupled problems (internal chaining, internal thermo-hydro-mechanical coupling, chaining with other codes); products and services. (J.S.)

  1. Optimal codes as Tanner codes with cyclic component codes

    DEFF Research Database (Denmark)

    Høholdt, Tom; Pinero, Fernando; Zeng, Peng

    2014-01-01

    In this article we study a class of graph codes with cyclic code component codes as affine variety codes. Within this class of Tanner codes we find some optimal binary codes. We use a particular subgraph of the point-line incidence plane of A(2,q) as the Tanner graph, and we are able to describe...... the codes succinctly using Gröbner bases....

  2. Proteomic comparison of the cytosolic proteins of three Bifidobacterium longum human isolates and B. longum NCC2705

    Directory of Open Access Journals (Sweden)

    Champomier-Vergès Marie-Christine

    2010-01-01

    Full Text Available Abstract Background Bifidobacteria are natural inhabitants of the human gastrointestinal tract. In full-term newborns, these bacteria are acquired from the mother during delivery and rapidly become the predominant organisms in the intestinal microbiota. Bifidobacteria contribute to the establishment of healthy intestinal ecology and can confer health benefits to their host. Consequently, there is growing interest in bifidobacteria, and various strains are currently used as probiotic components in functional food products. However, the probiotic effects have been reported to be strain-specific. There is thus a need to better understand the determinants of the observed benefits provided by these probiotics. Our objective was to compare three human B. longum isolates with the sequenced model strain B. longum NCC2705 at the chromosome and proteome levels. Results Pulsed field electrophoresis genotyping revealed genetic heterogeneity with low intraspecies strain relatedness among the four strains tested. Using two-dimensional gel electrophoresis, we analyzed qualitative differences in the cytosolic protein patterns. There were 45 spots that were present in some strains and absent in others. Spots were excised from the gels and subjected to peptide mass fingerprint analysis for identification. The 45 spots represented 37 proteins, most of which were involved in carbohydrate metabolism and cell wall or cell membrane synthesis. Notably, the protein patterns were correlated with differences in cell membrane properties like surface hydrophobicity and cell agglutination. Conclusion These results showed that proteomic analysis can be valuable for investigating differences in bifidobacterial species and may provide a better understanding of the diversity of bifidobacteria and their potential use as probiotics.

  3. Analysis of Power Laws, Shape Collapses, and Neural Complexity: New Techniques and MATLAB Support via the NCC Toolbox.

    Science.gov (United States)

    Marshall, Najja; Timme, Nicholas M; Bennett, Nicholas; Ripp, Monica; Lautzenhiser, Edward; Beggs, John M

    2016-01-01

    Neural systems include interactions that occur across many scales. Two divergent methods for characterizing such interactions have drawn on the physical analysis of critical phenomena and the mathematical study of information. Inferring criticality in neural systems has traditionally rested on fitting power laws to the property distributions of "neural avalanches" (contiguous bursts of activity), but the fractal nature of avalanche shapes has recently emerged as another signature of criticality. On the other hand, neural complexity, an information theoretic measure, has been used to capture the interplay between the functional localization of brain regions and their integration for higher cognitive functions. Unfortunately, treatments of all three methods-power-law fitting, avalanche shape collapse, and neural complexity-have suffered from shortcomings. Empirical data often contain biases that introduce deviations from true power law in the tail and head of the distribution, but deviations in the tail have often been unconsidered; avalanche shape collapse has required manual parameter tuning; and the estimation of neural complexity has relied on small data sets or statistical assumptions for the sake of computational efficiency. In this paper we present technical advancements in the analysis of criticality and complexity in neural systems. We use maximum-likelihood estimation to automatically fit power laws with left and right cutoffs, present the first automated shape collapse algorithm, and describe new techniques to account for large numbers of neural variables and small data sets in the calculation of neural complexity. In order to facilitate future research in criticality and complexity, we have made the software utilized in this analysis freely available online in the MATLAB NCC (Neural Complexity and Criticality) Toolbox.

  4. Numerical Analysis on Combustion Characteristic of Leaf Spring Rotary Engine

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2015-08-01

    Full Text Available The purpose of this paper is to investigate combustion characteristics for rotary engine via numerical studies. A 3D numerical model was developed to study the influence of several operative parameters on combustion characteristics. A novel rotary engine called, “Leaf Spring Rotary Engine”, was used to illustrate the structure and principle of the engine. The aims are to (1 improve the understanding of combustion process, and (2 quantify the influence of rotational speed, excess air ratio, initial pressure and temperature on combustion characteristics. The chamber space changed with crankshaft rotation. Due to the complexity of chamber volume, an equivalent modeling method was presented to simulate the chamber space variation. The numerical simulations were performed by solving the incompressible, multiphase Unsteady Reynolds-Averaged Navier–Stokes Equations via the commercial code FLUENT using a transport equation-based combustion model; a realizable  turbulence model and finite-rate/eddy-dissipation model were used to account for the effect of local factors on the combustion characteristics.

  5. Modelling of fuel spray and combustion in diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen, M.T.; Kaario, O.T. [VTT Energy, Espoo (Finland)

    1997-12-31

    Fuel spray and air motion characteristics and combustion in direct injection (DI) diesel engines was studied using computational models of the commercial CFD-code FIRE. Physical subprocesses modelled included Lagrangian spray droplet movement and behaviour (atomisation, evaporation and interaction of spray droplets) and combustion of evaporated liquid spray in the gas phase. Fuel vapour combustion rate was described by the model of Magnussen and Hjertager. The standard k,{epsilon}-model was used for turbulence. In order to be able to predict combustion accurately, the fuel spray penetration should be predicted with reasonable accuracy. In this study, the standard drag coefficient had to be reduced in order to match the computed penetration to the measured one. In addition, the constants in the submodel describing droplet breakup also needed to be adjusted for closer agreement with the measurements. The characteristic time scale of fuel consumption rate k/C{sub R} {epsilon} strongly influenced the heat release and in-cylinder pressure. With a value around 2.0 to 5.0 for C{sub R}, the computed in-cylinder pressure during the compression stroke agreed quite well with the measurements. On the other hand, the in-cylinder pressure was underpredicted during the expansion stroke. This is partly due to the fact that hydrocarbon fuel combustion was modelled as a one-step reaction reading to CO{sub 2} and H{sub 2}O and inadequate description of the mixing of reactants and combustion products. (author) 16 refs.

  6. Time Resolved FTIR Analysis of Combustion of Ethanol and Gasoline Combustion in AN Internal Combustion Engine

    Science.gov (United States)

    White, Allen R.; Sakai, Stephen; Devasher, Rebecca B.

    2011-06-01

    In order to pursue In Situ measurements in an internal combustion engine, a MegaTech Mark III transparent spark ignition engine was modified with a sapphire combustion chamber. This modification will allow the transmission of infrared radiation for time-resolved spectroscopic measurements by an infrared spectrometer. By using a Step-scan equipped Fourier transform spectrometer, temporally resolved infrared spectral data were acquired and compared for combustion in the modified Mark III engine. Measurements performed with the FTIR system provide insight into the energy transfer vectors that precede combustion and also provides an in situ measurement of the progress of combustion. Measurements were performed using ethanol and gasoline.

  7. Experimental chemical thermodynamics. Volume I. Combustion calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sunner, S.; Mansson, M. (eds.)

    1979-01-01

    This book contains 18 chapters. The information included is: units and physical constants; basic principles of combustion calorimetry; calibration of combustion calorimeters; test and auxiliary substances in combustion calorimetry; strategies in the calculation of standard-state energies of combustion from the experimentally determined quantities; assignments of uncertainties; presentation of combustion calorimetric data in the primary literature; general techniques for combustion of liquid/solid organic compounds by oxygen bomb calorimetry; combustion of liquid/solid organic compounds with non-metallic hetero-atoms; combustion calorimetry of metals and simple metallic compounds; combustion calorimetry of organometallic compounds; combustion in fluorine and other halogens; bomb combustion of gaseous compounds in oxygen; oxygen flame calorimetry; fluorine flame calorimetry; combustion calorimetry as a technological service; trends in combustion calorimetry; and from the history of combustion calorimetry. (DP)

  8. Chemical kinetics and combustion modelling with CFX 4

    Energy Technology Data Exchange (ETDEWEB)

    Stopford, P. [AEA Technology, Computational Fluid Dynamics Services Harwell, Oxfordshire (United Kingdom)

    1997-12-31

    The presentation describes some recent developments in combustion and kinetics models used in the CFX software of AEA Technology. Three topics are highlighted: the development of coupled solvers in a traditional `SIMPLE`-based CFD code, the use of detailed chemical kinetics mechanism via `look-up` tables and the application of CFD to large-scale multi-burner combustion plant. The aim is identify those physical approximations and numerical methods that are likely to be most useful in the future and those areas where further developments are required. (author) 6 refs.

  9. A role for the circadian clock protein Per1 in the regulation of the NaCl co-transporter (NCC) and the with-no-lysine kinase (WNK) cascade in mouse distal convoluted tubule cells.

    Science.gov (United States)

    Richards, Jacob; Ko, Benjamin; All, Sean; Cheng, Kit-Yan; Hoover, Robert S; Gumz, Michelle L

    2014-04-25

    It has been well established that blood pressure and renal function undergo circadian fluctuations. We have demonstrated that the circadian protein Per1 regulates multiple genes involved in sodium transport in the collecting duct of the kidney. However, the role of Per1 in other parts of the nephron has not been investigated. The distal convoluted tubule (DCT) plays a critical role in renal sodium reabsorption. Sodium is reabsorbed in this segment through the actions of the NaCl co-transporter (NCC), which is regulated by the with-no-lysine kinases (WNKs). The goal of this study was to test if Per1 regulates sodium transport in the DCT through modulation of NCC and the WNK kinases, WNK1 and WNK4. Pharmacological blockade of nuclear Per1 entry resulted in decreased mRNA expression of NCC and WNK1 but increased expression of WNK4 in the renal cortex of mice. These findings were confirmed by using Per1 siRNA and pharmacological blockade of Per1 nuclear entry in mDCT15 cells, a model of the mouse distal convoluted tubule. Transcriptional regulation was demonstrated by changes in short lived heterogeneous nuclear RNA. Chromatin immunoprecipitation experiments demonstrated interaction of Per1 and CLOCK with the promoters of NCC, WNK1, and WNK4. This interaction was modulated by blockade of Per1 nuclear entry. Importantly, NCC protein expression and NCC activity, as measured by thiazide-sensitive, chloride-dependent (22)Na uptake, were decreased upon pharmacological inhibition of Per1 nuclear entry. Taken together, these data demonstrate a role for Per1 in the transcriptional regulation of NCC, WNK1, and WNK4.

  10. A Role for the Circadian Clock Protein Per1 in the Regulation of the NaCl Co-transporter (NCC) and the with-no-lysine Kinase (WNK) Cascade in Mouse Distal Convoluted Tubule Cells*

    Science.gov (United States)

    Richards, Jacob; Ko, Benjamin; All, Sean; Cheng, Kit-Yan; Hoover, Robert S.; Gumz, Michelle L.

    2014-01-01

    It has been well established that blood pressure and renal function undergo circadian fluctuations. We have demonstrated that the circadian protein Per1 regulates multiple genes involved in sodium transport in the collecting duct of the kidney. However, the role of Per1 in other parts of the nephron has not been investigated. The distal convoluted tubule (DCT) plays a critical role in renal sodium reabsorption. Sodium is reabsorbed in this segment through the actions of the NaCl co-transporter (NCC), which is regulated by the with-no-lysine kinases (WNKs). The goal of this study was to test if Per1 regulates sodium transport in the DCT through modulation of NCC and the WNK kinases, WNK1 and WNK4. Pharmacological blockade of nuclear Per1 entry resulted in decreased mRNA expression of NCC and WNK1 but increased expression of WNK4 in the renal cortex of mice. These findings were confirmed by using Per1 siRNA and pharmacological blockade of Per1 nuclear entry in mDCT15 cells, a model of the mouse distal convoluted tubule. Transcriptional regulation was demonstrated by changes in short lived heterogeneous nuclear RNA. Chromatin immunoprecipitation experiments demonstrated interaction of Per1 and CLOCK with the promoters of NCC, WNK1, and WNK4. This interaction was modulated by blockade of Per1 nuclear entry. Importantly, NCC protein expression and NCC activity, as measured by thiazide-sensitive, chloride-dependent 22Na uptake, were decreased upon pharmacological inhibition of Per1 nuclear entry. Taken together, these data demonstrate a role for Per1 in the transcriptional regulation of NCC, WNK1, and WNK4. PMID:24610784

  11. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  12. Advanced modeling of oxy-fuel combustion of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Chungen Yin

    2011-01-15

    The main goal of this small-scale project is to investigate oxy-combustion of natural gas (NG) through advanced modeling, in which radiation, chemistry and mixing will be reasonably resolved. 1) A state-of-the-art review was given regarding the latest R and D achievements and status of oxy-fuel technology. The modeling and simulation status and achievements in the field of oxy-fuel combustion were also summarized; 2) A computer code in standard c++, using the exponential wide band model (EWBM) to evaluate the emissivity and absorptivity of any gas mixture at any condition, was developed and validated in detail against data in literature. A new, complete, and accurate WSGGM, applicable to both air-fuel and oxy-fuel combustion modeling and applicable to both gray and non-gray calculation, was successfully derived, by using the validated EWBM code as the reference mode. The new WSGGM was implemented in CFD modeling of two different oxy-fuel furnaces, through which its great, unique advantages over the currently most widely used WSGGM were demonstrated. 3) Chemical equilibrium calculations were performed for oxy-NG flame and air-NG flame, in which dissociation effects were considered to different degrees. Remarkable differences in oxy-fuel and air-fuel combustion were revealed, and main intermediate species that play key roles in oxy-fuel flames were identified. Different combustion mechanisms are compared, e.g., the most widely used 2-step global mechanism, refined 4-step global mechanism, a global mechanism developed for oxy-fuel using detailed chemical kinetic modeling (CHEMKIN) as reference. 4) Over 15 CFD simulations were done for oxy-NG combustion, in which radiation, chemistry, mixing, turbulence-chemistry interactions, and so on were thoroughly investigated. Among all the simulations, RANS combined with 2-step and refined 4-step mechanism, RANS combined with CHEMKIN-based new global mechanism for oxy-fuel modeling, and LES combined with different combustion

  13. Combustion science and engineering

    CERN Document Server

    Annamalai, Kalyan

    2006-01-01

    Introduction and Review of Thermodynamics Introduction Combustion Terminology Matter and Its Properties Microscopic Overview of Thermodynamics Conservation of Mass and Energy and the First Law of Thermodynamics The Second Law of Thermodynamics Summary Stoichiometry and Thermochemistry of Reacting Systems Introduction Overall Reactions Gas Analyses Global Conservation Equations for Reacting Systems Thermochemistry Summary Appendix Reaction Direction and Equilibrium Introduction Reaction Direction and Chemical Equilibrium Chemical Equilibrium Relations Vant Hoff Equation Adi

  14. Combustion Characteristics of Sprays

    Science.gov (United States)

    1989-08-01

    regarded by implication or otherwise, or in any way licensing the holder or any other person or corporation, or conveying any rights or permission to...00 _’N 1. TI TLE inctuat Security CZaaafication5 Combustion Characteristics of Sprays 12. PERSONAL AUTHOR(S) Sohrab, Siavash H. 13& TYPE OF REPORT...to ?!HF of rich butane/air 3unsen flames. .lso, the rotacion speed and :he oerodic temDeracure fluc:uations of rotacfng ?HF are examined. :’!naily

  15. Combustible Cartridge Case Characterization

    Science.gov (United States)

    1984-02-01

    University (NYU) has resulted in the selection of two cross-linked melamine / formaldehyde acrylic styrene resin systems that can be used in the beater additive... melamine resin Akaradit II stabilizer 20. ABSTRACT (con) Test coupons of combustible cartridge case material were fabricated using these recommended...and agitated for 30 min before the pH was slowly lowered to 3 with p-toluene sulfonic acid. In order to maintain this pH in the felting tank, it was

  16. High Gravity (g) Combustion

    Science.gov (United States)

    2006-02-01

    required thrust-to-weight ratio goals. Shorter residence times in the combustion chamber may reduce the NOx emissions, but the CO and UHC emissions then...Emissions analyzing equipment is available to detect CO, CO2, NOx, O2, and total unburned hydrocarbons ( UHC ) at the combustor exit plane. Emissions... UHC ) emissions along with the CO data, as seen in Fig. 24, shows that Configuration 1 had much higher UHC levels. The reactions from hydrocarbons to

  17. Internal combustion engine using premixed combustion of stratified charges

    Science.gov (United States)

    Marriott, Craig D.; Reitz, Rolf D. (Madison, WI

    2003-12-30

    During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

  18. The Diesel Combustion Collaboratory: Combustion Researchers Collaborating over the Internet

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Pancerella; L. A. Rahn; C. Yang

    2000-02-01

    The Diesel Combustion Collaborator (DCC) is a pilot project to develop and deploy collaborative technologies to combustion researchers distributed throughout the DOE national laboratories, academia, and industry. The result is a problem-solving environment for combustion research. Researchers collaborate over the Internet using DCC tools, which include: a distributed execution management system for running combustion models on widely distributed computers, including supercomputers; web-accessible data archiving capabilities for sharing graphical experimental or modeling data; electronic notebooks and shared workspaces for facilitating collaboration; visualization of combustion data; and video-conferencing and data-conferencing among researchers at remote sites. Security is a key aspect of the collaborative tools. In many cases, the authors have integrated these tools to allow data, including large combustion data sets, to flow seamlessly, for example, from modeling tools to data archives. In this paper the authors describe the work of a larger collaborative effort to design, implement and deploy the DCC.

  19. Internal combustion piston engines

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1977-07-01

    Current worldwide production of internal combustion piston engines includes many diversified types of designs and a very broad range of sizes. Engine sizes range from a few horsepower in small mobile units to over 40,000 brake horsepower in large stationary and marine units. The key characteristics of internal combustion piston engines considered appropriate for use as prime movers in Integrated Community Energy Systems (ICES) are evaluated. The categories of engines considered include spark-ignition gas engines, compression-ignition oil (diesel) engines, and dual-fuel engines. The engines are evaluated with respect to full-load and part-load performance characteristics, reliability, environmental concerns, estimated 1976 cost data, and current and future status of development. The largest internal combustion piston engines manufactured in the United States range up to 13,540 rated brake horsepower. Future development efforts are anticipated to result in a 20 to 25% increase in brake horsepower without increase in or loss of weight, economy, reliability, or life expectancy, predicated on a simple extension of current development trends.

  20. Issues in waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Lennart; Robertson, Kerstin; Tullin, Claes [Swedish National Testing and Research Inst., Boraas (Sweden); Sundquist, Lena; Wrangensten, Lars [AaF-Energikonsult AB, Stockholm (Sweden); Blom, Elisabet [AaF-Processdesign AB, Stockholm (Sweden)

    2003-05-01

    The main purpose of this review is to provide an overview of the state-of-the-art on research and development issues related to waste combustion with relevance for Swedish conditions. The review focuses on co-combustion in grate and fluidised bed furnaces. It is primarily literature searches in relevant databases of scientific publications with to material published after 1995. As a complement, findings published in different report series, have also been included. Since the area covered by this report is very wide, we do not claim to cover the issues included completely and it has not been possitile to evaluate the referred studies in depth. Basic knowledge about combustion issues is not included since such information can be found elsewhere in the literature. Rather, this review should be viewed as an overview of research and development in the waste-to-energy area and as such we hope that it will inspire scientists and others to further work in relevant areas.

  1. Development of flameless combustion; Desarrollo de la combustion sin flama

    Energy Technology Data Exchange (ETDEWEB)

    Flores Sauceda, M. Leonardo; Cervantes de Gortari, Jaime Gonzalo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: 8344afc@prodigy.net.mx; jgonzalo@servidor.unam.mx

    2010-11-15

    The paper intends contribute to global warming mitigation joint effort that develops technologies to capture the CO{sub 2} produced by fossil fuels combustion and to reduce emission of other greenhouse gases like the NO{sub x}. After reviewing existing combustion bibliography is pointed out that (a) touches only partial aspects of the collective system composed by Combustion-Heat transfer process-Environment, whose interactions are our primary interest and (b) most specialists think there is not yet a clearly winning technology for CO{sub 2} capture and storage. In this paper the study of combustion is focused as integrated in the aforementioned collective system where application of flameless combustion, using oxidant preheated in heat regenerators and fluent gas recirculation into combustion chamber plus appropriated heat and mass balances, simultaneously results in energy saving and environmental impact reduction. [Spanish] El trabajo pretende contribuir al esfuerzo conjunto de mitigacion del calentamiento global que aporta tecnologias para capturar el CO{sub 2} producido por la combustion de combustibles fosiles y para disminuir la emision de otros gases invernadero como NOx. De revision bibliografica sobre combustion se concluye que (a) trata aspectos parciales del sistema compuesto por combustion-proceso de trasferencia de calor-ambiente, cuyas interacciones son nuestro principal interes (b) la mayoria de especialistas considera no hay todavia una tecnologia claramente superior a las demas para captura y almacenaje de CO{sub 2}. Se estudia la combustion como parte integrante del mencionado sistema conjunto, donde la aplicacion de combustion sin flama, empleando oxidante precalentado mediante regeneradores de calor y recirculacion de gases efluentes ademas de los balances de masa y energia adecuados, permite tener simultaneamente ahorros energeticos e impacto ambiental reducido.

  2. Multi-year Simulations and Experimental Seasonal Predictions for Rainy Seasons in China by Using a Nested Regional Climate Model (RegCM_NCC). Part Ⅰ: Sensitivity Study

    Institute of Scientific and Technical Information of China (English)

    DING Yihui; SHI Xueli; LIU Yiming; LIU Yan; LI Qingquan; QIAN Yongfu; MIAO Manqian; ZHAI Guoqing; GAO Kun

    2006-01-01

    A modified version of the NCAR/RegCM2 has been developed at the National Climate Center (NCC), China Meteorological Administration, through a series of sensitivity experiments and multi-year simulations and hindcasts, with a special emphasis on the adequate choice of physical parameterization schemes suitable for the East Asian monsoon climate. This regional climate model is nested with the NCC/IAP (Institute of Atmospheric Physics) T63 coupled GCM to make an experimental seasonal prediction for China and East Asia. The four-year (2001 to 2004) prediction results are encouraging. This paper is the first part of a two-part paper, and it mainly describes the sensitivity study of the physical process parameterization represented in the model. The systematic errors produced by the different physical parameterization schemes such as the land surface processes, convective precipitation, cloud-radiation transfer process, boundary layer process and large-scale terrain features have been identified based on multi-year and extreme flooding event simulations. A number of comparative experiments has shown that the mass flux scheme (MFS) and Betts-Miller scheme (BM) for convective precipitation, the LPMI (land surface process model I) and LPMII (land surface process model Ⅱ) for the land surface process, the CCM3 radiation transfer scheme for cloud-radiation transfer processes, the TKE (turbulent kinetic energy) scheme for the boundary layer processes and the topography treatment schemes for the Tibetan Plateau are suitable for simulations and prediction of the East Asia monsoon climate in rainy seasons. Based on the above sensitivity study, a modified version of the RegCM2 (RegCM_NCC) has been set up for climate simulations and seasonal predictions.

  3. Decreased ENaC expression compensates the increased NCC activity following inactivation of the kidney-specific isoform of WNK1 and prevents hypertension.

    Science.gov (United States)

    Hadchouel, Juliette; Soukaseum, Christelle; Büsst, Cara; Zhou, Xiao-ou; Baudrie, Véronique; Zürrer, Tany; Cambillau, Michelle; Elghozi, Jean-Luc; Lifton, Richard P; Loffing, Johannes; Jeunemaitre, Xavier

    2010-10-19

    Mutations in WNK1 and WNK4 lead to familial hyperkalemic hypertension (FHHt). Because FHHt associates net positive Na(+) balance together with K(+) and H(+) renal retention, the identification of WNK1 and WNK4 led to a new paradigm to explain how aldosterone can promote either Na(+) reabsorption or K(+) secretion in a hypovolemic or hyperkalemic state, respectively. WNK1 gives rise to L-WNK1, an ubiquitous kinase, and KS-WNK1, a kinase-defective isoform expressed in the distal convoluted tubule. By inactivating KS-WNK1 in mice, we show here that this isoform is an important regulator of sodium transport. KS-WNK1(-/-) mice display an increased activity of the Na-Cl cotransporter NCC, expressed specifically in the distal convoluted tubule, where it participates in the fine tuning of sodium reabsorption. Moreover, the expression of the ROMK and BKCa potassium channels was modified in KS-WNK1(-/-) mice, indicating that KS-WNK1 is also a regulator of potassium transport in the distal nephron. Finally, we provide an alternative model for FHHt. Previous studies suggested that the activation of NCC plays a central role in the development of hypertension and hyperkalemia. Even though the increase in NCC activity in KS-WNK1(-/-) mice was less pronounced than in mice overexpressing a mutant form of WNK4, our study suggests that the activation of Na-Cl cotransporter is not sufficient by itself to induce a hyperkalemic hypertension and that the deregulation of other channels, such as the Epithelial Na(+) channel (ENaC), is probably required.

  4. Effect of heterozygous deletion of WNK1 on the WNK-OSR1/ SPAK-NCC/NKCC1/NKCC2 signal cascade in the kidney and blood vessels.

    Science.gov (United States)

    Susa, Koichiro; Kita, Satomi; Iwamoto, Takahiro; Yang, Sung-Sen; Lin, Shih-Hua; Ohta, Akihito; Sohara, Eisei; Rai, Tatemitsu; Sasaki, Sei; Alessi, Dario R; Uchida, Shinichi

    2012-08-01

    We found that a mechanism of hypertension in pseudohypoaldosteronism type II (PHAII) caused by a WNK4 missense mutation (D561A) was activation of the WNK-OSR1/SPAK-NCC signal cascade. However, the pathogenic effect of intronic deletions in WNK1 genes also observed in PHAII patients remains unclear. To understand the pathophysiological roles of WNK1 in vivo, WNK1(+/-)mice have been analyzed, because homozygous WNK1 knockout is embryonic lethal. Although WNK1(+/-) mice have been reported to have hypotension, detailed analyses of the WNK signal cascade in the kidney and other organs of WNK1(+/-) mice have not been performed. We assess the effect of heterozygous deletion of WNK1 on the WNK-OSR1/SPAK-NCC/NKCC1/NKCC2 signal cascade in the kidney and blood vessels. Contrary to the previous report, the blood pressure of WNK1(+/-) mice was not decreased, even under a low-salt diet. Under a WNK4(D561A/+) background, the heterozygous deletion of the WNK1 gene did not reduce the high blood pressure either. We then evaluated the phosphorylation status of OSR1, SPAK, NCC, NKCC1, and NKCC2 in the kidney, but no significant decrease in the phosphorylation was observed in WNK1(+/-) mice or WNK1(+/-)WNK4(D561A/+) mice. In contrast, a significant decrease in NKCC1 phosphorylation in the aorta and a decreased pressure-induced myogenic response in the mesenteric arteries were observed in WNK1(+/-) mice. The contribution of WNK1 to total WNK kinase activity in the kidney may be small, but that WNK1 may play a substantial role in the regulation of blood pressure in the arteries.

  5. Mining novel starch-converting Glycoside Hydrolase 70 enzymes from the Nestlé Culture Collection genome database: The Lactobacillus reuteri NCC 2613 GtfB.

    Science.gov (United States)

    Gangoiti, Joana; van Leeuwen, Sander S; Meng, Xiangfeng; Duboux, Stéphane; Vafiadi, Christina; Pijning, Tjaard; Dijkhuizen, Lubbert

    2017-08-30

    The Glycoside hydrolase (GH) family 70 originally was established for glucansucrases of lactic acid bacteria (LAB) converting sucrose into α-glucan polymers. In recent years we have identified 3 subfamilies of GH70 enzymes (designated GtfB, GtfC and GtfD) as 4,6-α-glucanotransferases, cleaving (α1 → 4)-linkages in maltodextrins/starch and synthesizing new (α1 → 6)-linkages. In this work, 106 putative GtfBs were identified in the Nestlé Culture Collection genome database with ~2700 genomes, and the L. reuteri NCC 2613 one was selected for further characterization based on variations in its conserved motifs. Using amylose the L. reuteri NCC 2613 GtfB synthesizes a low-molecular-mass reuteran-like polymer consisting of linear (α1 → 4) sequences interspersed with (α1 → 6) linkages, and (α1 → 4,6) branching points. This product specificity is novel within the GtfB subfamily, mostly comprising 4,6-α-glucanotransferases synthesizing consecutive (α1 → 6)-linkages. Instead, its activity resembles that of the GtfD 4,6-α-glucanotransferases identified in non-LAB strains. This study demonstrates the potential of large-scale genome sequence data for the discovery of enzymes of interest for the food industry. The L. reuteri NCC 2613 GtfB is a valuable addition to the starch-converting GH70 enzyme toolbox. It represents a new evolutionary intermediate between families GH13 and GH70, and provides further insights into the structure-function relationships of the GtfB subfamily enzymes.

  6. Post combustion in converter steelmaking

    Energy Technology Data Exchange (ETDEWEB)

    Oghbasilasie, H.; Holappa, L.

    1997-12-31

    The purpose of this work is to study the fundamentals of post combustion and the effect of different process parameters on the post combustion ratio (PCR) and heat transfer efficiency (HTE) in converter steelmaking process. The PCR and HTE have been determined under normal operating conditions. Trials assessed the effect of lance height, vessel volume, foaming slag and pellet additions on PCR and HTE. Based on enthalpy considerations, post combustion of CO gas is regarded as one of the most effective means of increasing the heat supply to the BOP. The thermodynamic study of gas-metal-slag reactions gives the limiting conditions for post combustion inside the converter reactor. Different process parameters influencing both thermodynamic equilibria and kinetic conditions can greatly affect the post combustion ratio. Different features of converter processes as well smelting reduction processes utilizing post combustion have been reviewed. (orig.) SULA 2 Research Programme; 26 refs.

  7. Sulfur Chemistry in Combustion I

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Glarborg, Peter

    2000-01-01

    of the sulphur compounds in fossil fuels and the possibilities to remove them will be given. Then the combustion of sulphur species and their influence on the combustion chemistry and especially on the CO oxidation and the NOx formation will be described. Finally the in-situ removal of sulphur in the combustion...... process by reaction between SO2 and calcium containing sorbents and the influence on the NOx chemistry will be treated....

  8. Numerical and Experimental Study on the Combustion and Emission Characteristics of a Dimethyl Ether (DME) Fueled Compression Ignition Engine Études numériques et expérimentales sur les caractéristiques de combustion et d’émissions d’un éther diméthylique (EDM)- moteur à auto-allumage rempli de combustible

    National Research Council Canada - National Science Library

    Kim Hyung Jun; Park Sung Wook; Lee Chang Sik

    2012-01-01

    ...) with wide ranges of injection timings in compression ignition engines. In order to simulate DME combustion processes, a KIVA-3V code coupled with a chemistry solver was used to solve the detailed chemical kinetics model of DME oxidation...

  9. Pulsating combustion - Combustion characteristics and reduction of emissions

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, Annika

    1999-11-01

    In the search for high efficiency combustion systems pulsating combustion has been identified as one of the technologies that potentially can meet the objectives of clean combustion and good fuel economy. Pulsating combustion offers low emissions of pollutants, high heat transfer and efficient combustion. Although it is an old technology, the interest in pulsating combustion has been renewed in recent years, due to its unique features. Various applications of pulsating combustion can be found, mainly as drying and heating devices, of which the latter also have had commercial success. It is, however, in the design process of a pulse combustor, difficult to predict the operating frequency, the heat release etc., due to the lack of a well founded theory of the phenomenon. Research concerning control over the combustion process is essential for developing high efficiency pulse combustors with low emissions. Natural gas fired Helmholtz type pulse combustors have been the experimental objects of this study. In order to investigate the interaction between the fluid dynamics and the chemistry in pulse combustors, laser based measuring techniques as well as other conventional measuring techniques have been used. The experimental results shows the possibilities to control the combustion characteristics of pulsating combustion. It is shown that the time scales in the large vortices created at the inlet to the combustion chamber are very important for the operation of the pulse combustor. By increasing/decreasing the time scale for the large scale mixing the timing of the heat release is changed and the operating characteristics of the pulse combustor changes. Three different means for NO{sub x} reduction in Helmholtz type pulse combustors have been investigated. These include exhaust gas recirculation, alteration of air/fuel ratio and changed inlet geometry in the combustion chamber. All used methods achieved less than 10 ppm NO{sub x} emitted (referred to stoichiometric

  10. NOVEL BIPHASE CODE -INTEGRATED SIDELOBE SUPPRESSION CODE

    Institute of Scientific and Technical Information of China (English)

    Wang Feixue; Ou Gang; Zhuang Zhaowen

    2004-01-01

    A kind of novel binary phase code named sidelobe suppression code is proposed in this paper. It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes. It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes-Barker codes. For example, the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length.

  11. The modes of gaseous combustion

    CERN Document Server

    Rubtsov, Nickolai M

    2016-01-01

    This book provides an analysis of contemporary problems in combustion science, namely flame propagation, detonation and heterophaseous combustion based on the works of the author. The current problems in the area of gas combustion, as well as the methods allowing to calculate and estimate limiting conditions of ignition, and flame propagation on the basis of experimental results are considered. The book focuses on the virtually inaccessible works of Russian authors and will be useful for experienced students and qualified scientists in the area of experimental studies of combustion processes.

  12. Combustion from basics to applications

    CERN Document Server

    Lackner, Maximilian; Winter, Franz

    2013-01-01

    Combustion, the process of burning, is defined as a chemical reaction between a combustible reactant (the fuel) and an oxidizing agent (such as air) in order to produce heat and in most cases light while new chemical species (e.g., flue gas components) are formed. This book covers a gap on the market by providing a concise introduction to combustion. Most of the other books currently available are targeted towards the experienced users and contain too many details and/or contain knowledge at a fairly high level. This book provides a brief and clear overview of the combustion basics, suitable f

  13. Mathematical Modeling in Combustion Science

    CERN Document Server

    Takeno, Tadao

    1988-01-01

    An important new area of current research in combustion science is reviewed in the contributions to this volume. The complicated phenomena of combustion, such as chemical reactions, heat and mass transfer, and gaseous flows, have so far been studied predominantly by experiment and by phenomenological approaches. But asymptotic analysis and other recent developments are rapidly changing this situation. The contributions in this volume are devoted to mathematical modeling in three areas: high Mach number combustion, complex chemistry and physics, and flame modeling in small scale turbulent flow combustion.

  14. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the...

  15. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the operational...

  16. Basic Aerodynamics of Combustion Chambers,

    Science.gov (United States)

    1981-05-20

    8217, tie imnrulse foree eyuilibr-um c’ the bomd’~ leye - is 173 pv-:irJ p~76vJbK 2sO) IL !-. = Zn pT -- a , bV T. z -,,r y.re C era 3oia * ~~I" onc art-=e...heat by combustion all have very large influences on the capabilities of a combustion chamber. A yellow- colored flame represents diffusion combustion in...the wakes of fuel droplets. Blue- colored flames represent gaseous combustion of evaporated vapors which have already left the fuel droplets. The

  17. From concatenated codes to graph codes

    DEFF Research Database (Denmark)

    Justesen, Jørn; Høholdt, Tom

    2004-01-01

    We consider codes based on simple bipartite expander graphs. These codes may be seen as the first step leading from product type concatenated codes to more complex graph codes. We emphasize constructions of specific codes of realistic lengths, and study the details of decoding by message passing...

  18. A dominant nuclear mutation in Chlamydomonas identifies a factor controlling chloroplast mRNA stability by acting on the coding region of the atpA transcript.

    Science.gov (United States)

    Drapier, Dominique; Girard-Bascou, Jacqueline; Stern, David B; Wollman, Francis-André

    2002-09-01

    We have characterized a nuclear mutation, mda1-ncc1, that affects mRNA stability for the atpA gene cluster in the chloroplast of Chlamydomonas. Unlike all nuclear mutations altering chloroplast gene expression described to date, mda1-ncc1 is a dominant mutation that still allows accumulation of detectable amounts of atpA mRNAs. At variance with the subset of these mutations that affect mRNA stability through the 5' UTR of a single chloroplast transcript, the mutated version of MDA1 acts on the coding region of the atpA message. We discuss the action of MDA1 in relation to the unusual pattern of expression of atpA that associates particularly short lived-transcripts with a very high translational efficiency.

  19. CFD simulation of gas and particles combustion in biomass furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Griselin, Nicolas

    2000-11-01

    In this thesis, gas and particle combustion in biomass furnaces is investigated numerically. The aim of this thesis is to use Computational Fluid Dynamics (CFD) technology as an effective computer based simulation tool to study and develop the combustion processes in biomass furnaces. A detailed model for the numerical simulation of biomass combustion in a furnace, including fixed-bed modeling, gas-phase calculation (species distribution, temperature field, flow field) and gas-solid two-phase interaction for flying burning particles is presented. This model is used to understand the mechanisms of combustion and pollutant emissions under different conditions in small scale and large scale furnaces. The code used in the computations was developed at the Division of Fluid Mechanics, LTH. The flow field in the combustion enclosure is calculated by solving the Favre-averaged Navier-Stokes equations, with standard {kappa} - {epsilon} turbulence closure, together with the energy conservation equation and species transport equations. Discrete transfer method is used for calculating the radiation source term in the energy conservation equation. Finite difference is used to solve the general form of the equation yielding solutions for gas-phase temperatures, velocities, turbulence intensities and species concentrations. The code has been extended through this work in order to include two-phase flow simulation of particles and gas combustion. The Favre-averaged gas equations are solved in a Eulerian framework while the submodels for particle motion and combustion are used in the framework of a Lagrangian approach. Numerical simulations and measurement data of unburned hydrocarbons (UHC), CO, H{sub 2}, O{sub 2} and temperature on the top of the fixed bed are used to model the amount of tar and char formed during pyrolysis and combustion of biomass fuel in the bed. Different operating conditions are examined. Numerical calculations are compared with the measured data. It is

  20. Optimization of Post Combustion in Steelmaking (TRP 9925)

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Richard J. Fruehan; Dr. R. J. Matway

    2004-03-31

    In the electric arc furnace (EAF), and the basic oxygen furnace (BOF) for producing steel, the major off gas is carbon monoxide (CO). If the CO can be combusted to CO{sub 2}, and the energy transferred to the metal, this reaction will reduce the energy consumed in the EAF and allow for more scrap melting in the BOF which would significantly lower the energy required to produce steel. This reaction is referred to as post combustion. In order to optimize the post combustion process, computational fluid dynamic models (CFD) of the two steelmaking processes were developed. Before the models could be fully developed information on reactions affecting post combustion had to be obtained. The role of the reaction of CO{sub 2} with scrap (iron) was measured at the temperatures relevant to post combustion in laboratory experiments. The experiments were done to separate the effects of gas phase mass transfer, chemical kinetics, and solid state mass transfer through the iron oxide formed by the reaction. The first CFD model was for the EAF using the FIDAP-CFD{trademark} code. Whereas this model gave some useful results it was incomplete due to problems with the FIDAP program. In the second EAF model, the CFX{trademark} code was used and was much more successful. The full 3-D model included all forms of heat transfer and the back reactions of CO{sub 2} with the metal and scrap. The model for the EAF was a full 3-D model and consisted of a primary oxygen lance with side wall injectors for post combustion. The model could predict the degree of post combustion and heat transfer. The BOF model was a slice of the BOF for which there was symmetry. The model could predict post combustion, heat transfer, temperature profiles and the effect of operating variables such as oxygen flow rates and distribution. The present research developed several new models such as limited combustion and depostcombustion. These were all documented by MSA Pass as a sub-contract. Instruction manuals were

  1. Combustion Branch Website Development

    Science.gov (United States)

    Bishop, Eric

    2004-01-01

    The NASA combustion branch is a leader in developing and applying combustion science to focused aerospace propulsion systems concepts. It is widely recognized for unique facilities, analytical tools, and personnel. In order to better communicate the outstanding research being done in this Branch to the public and other research organization, a more substantial website was desired. The objective of this project was to build an up-to-date site that reflects current research in a usable and attractive manner. In order to accomplish this, information was requested from all researchers in the Combustion branch, on their professional skills and on the current projects. This information was used to fill in the Personnel and Research sections of the website. A digital camera was used to photograph all personnel and these photographs were included in the personnel section as well. The design of the site was implemented using the latest web standards: xhtml and external css stylesheets. This implementation conforms to the guidelines recommended by the w3c. It also helps to ensure that the web site is accessible by disabled users, and complies with Section 508 Federal legislation (which mandates that all Federal websites be accessible). Graphics for the new site were generated using the gimp (www.gimp.org) an open-source graphics program similar to Adobe Photoshop. Also, all graphics on the site were of a reasonable size (less than 20k, most less than 2k) so that the page would load quickly. Technologies such as Macromedia Flash and Javascript were avoided, as these only function on some clients which have the proper software installed or enabled. The website was tested on different platforms with many different browsers to ensure there were no compatibility issues. The website was tested on windows with MS IE 6, MSIE 5 , Netscape 7, Mozilla and Opera. On a Mac, the site was tested with MS IE 5 , Netscape 7 and Safari.

  2. Alternate fuels; Combustibles alternos

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana. Iztapalapa (Mexico)

    2003-07-01

    In the definition and description of alternate fuels we must center ourselves in those technological alternatives that allow to obtain compounds that differ from the traditional ones, in their forms to be obtained. In this article it is tried to give an overview of alternate fuels to the conventional derivatives of petroleum and that allow to have a clear idea on the tendencies of modern investigation and the technological developments that can be implemented in the short term. It is not pretended to include all the tendencies and developments of the present world, but those that can hit in a relatively short term, in accordance with agreed with the average life of conventional fuels. Nevertheless, most of the conversion principles are applicable to the spectrum of carbonaceous or cellulosic materials which are in nature, are cultivated or wastes of organic origin. Thus one will approach them in a successive way, the physical, chemical and biological conversions that can take place in a production process of an alternate fuel or the same direct use of the fuel such as burning the sweepings derived from the forests. [Spanish] En la definicion y descripcion de combustibles alternos nos debemos centrar en aquellas alternativas tecnologicas que permitan obtener compuestos que difieren de los tradicionales, al menos en sus formas de ser obtenidos. En este articulo se pretende dar un panorama de los combustibles alternos a los convencionales derivados del petroleo y que permita tener una idea clara sobre las tendencias de la investigacion moderna y los desarrollos tecnologicos que puedan ser implementados en el corto plazo. No se pretende abarcar todas las tendencias y desarrollos del mundo actual, sino aquellas que pueden impactar en un plazo relativamente corto, acordes con la vida media de los combustibles convencionales. Sin embargo, la mayor parte de los principios de conversion son aplicables al espectro de materiales carbonaceos o celulosicos los cuales se

  3. Combustion Stratification for Naphtha from CI Combustion to PPC

    KAUST Repository

    Vallinayagam, R.

    2017-03-28

    This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O concentration in the intake is decreased to 17.7% and 14

  4. AIR EMISSIONS FROM SCRAP TIRE COMBUSTION

    Science.gov (United States)

    The report discusses air emissions from two types of scrap tire combustion: uncontrolled and controlled. Uncontrolled sources are open tire fires, which produce many unhealthful products of incomplete combustion and release them directly into the atmosphere. Controlled combustion...

  5. Path planning during combustion mode switch

    Science.gov (United States)

    Jiang, Li; Ravi, Nikhil

    2015-12-29

    Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

  6. Modelling of coal combustion enhanced through plasma-fuel systems in full-scale boilers

    Energy Technology Data Exchange (ETDEWEB)

    A.S. Askarova; Z. Jankoski; E.I. Karpenko; E.I. Lavrischeva; F.C. Lockwood; V.E. Messerle; A.B. Ustimenko [al-Farabi Kazakh National University, Almaty (Kazakhstan). Department of Physics

    2005-07-01

    Plasma activation promotes more effective and environmental friendly low-rank coal combustion. This work presents numerical modelling results of plasma thermochemical preparation of pulverized coal for ignition and combustion in the furnace of a utility boiler. Two kinetic mathematical models were used in the investigation of the processes of air-fuel mixture plasma activation, ignition and combustion. A 1D kinetic code, PLASMA-COAL, calculates the concentrations of species, temperatures and velocities of treated coal-air mixtures in a burner incorporating a plasma source. It gives initial data for 3D-modeling of power boilers furnaces by the code FLOREAN. A comprehensive image of plasma activated coal combustion processes in a furnace of pulverised coal fired boiler was obtained. The advantages of the plasma technology are clearly demonstrated. 15 refs., 6 figs., 4 tabs.

  7. Plasma-supported coal combustion in boiler furnace

    Energy Technology Data Exchange (ETDEWEB)

    Askarova, A.S.; Karpenko, E.I.; Lavrishcheva, Y.I.; Messerle, V.E.; Ustimenko, A.B. [Kazakh National University, Alma Ata (Kazakhstan). Dept. of Physics

    2007-12-15

    Plasma activation promotes more effective and environmentally friendly low-rank coal combustion. This paper presents Plasma Fuel Systems that increase the burning efficiency of coal. The systems were tested for fuel oil-free start-up of coal-fired boilers and stabilization of a pulverized-coal flame in power-generating boilers equipped with different types of burners, and burning all types of power-generating coal. Also, numerical modeling results of a plasma thermochemical preparation of pulverized coal for ignition and combustion in the furnace of a utility boiler are discussed in this paper. Two kinetic mathematical models were used in the investigation of the processes of air/fuel mixture plasma activation: ignition and combustion. A I-D kinetic code PLASMA-COAL calculates the concentrations of species, temperatures, and velocities of the treated coal/air mixture in a burner incorporating a plasma source. The I-D simulation results are initial data for the 3-D-modeling of power boiler furnaces by the code FLOREAN. A comprehensive image of plasma-activated coal combustion processes in a furnace of a pulverized-coal-fired boiler was obtained. The advantages of the plasma technology are clearly demonstrated.

  8. Good Codes From Generalised Algebraic Geometry Codes

    CERN Document Server

    Jibril, Mubarak; Ahmed, Mohammed Zaki; Tjhai, Cen

    2010-01-01

    Algebraic geometry codes or Goppa codes are defined with places of degree one. In constructing generalised algebraic geometry codes places of higher degree are used. In this paper we present 41 new codes over GF(16) which improve on the best known codes of the same length and rate. The construction method uses places of small degree with a technique originally published over 10 years ago for the construction of generalised algebraic geometry codes.

  9. A high-order immersed boundary method for high-fidelity turbulent combustion simulations

    Science.gov (United States)

    Minamoto, Yuki; Aoki, Kozo; Osawa, Kosuke; Shi, Tuo; Prodan, Alexandru; Tanahashi, Mamoru

    2016-11-01

    Direct numerical simulations (DNS) have played important roles in the research of turbulent combustion. With the recent advancement in high-performance computing, DNS of slightly complicated configurations such as V-, various jet and swirl flames have been performed, and such DNS will further our understanding on the physics of turbulent combustion. Since these configurations include walls that do not necessarily conform with the preferred mesh coordinates for combustion DNS, most of these simulations use presumed profiles for inflow/near-wall flows as boundary conditions. A high-order immersed boundary method suited for parallel computation is one way to improve these simulations. The present research implements such a boundary technique in a combustion DNS code, and simulations are performed to confirm its accuracy and performance. This work was partly supported by Council for Science, Technology and Innovation, Cross-ministerial Strategic Innovation Promotion Program (SIP), "Innovative Combustion Technology" (Funding agency: JST).

  10. Combustion & Laser Diagnostics Research Complex (CLDRC)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Combustion and Laser Diagnostics Research Complex (CLRDC) supports the experimental and computational study of fundamental combustion phenomena to...

  11. Mission Success for Combustion Science

    Science.gov (United States)

    Weiland, Karen J.

    2004-01-01

    This presentation describes how mission success for combustion experiments has been obtained in previous spaceflight experiments and how it will be obtained for future International Space Station (ISS) experiments. The fluids and combustion facility is a payload planned for the ISS. It is composed of two racks: the fluids Integrated rack and the Combustion INtegrated Rack (CIR). Requirements for the CIR were obtained from a set of combustion basis experiments that served as surrogates for later experiments. The process for experiments that fly on the ISS includes proposal selection, requirements and success criteria definition, science and engineering reviews, mission operations, and postflight operations. By following this process, the microgravity combustion science program has attained success in 41 out of 42 experiments.

  12. Modeling of Pulverized Coal Combustion in Cement Rotary Kiln

    OpenAIRE

    2006-01-01

    In this paper, based on analysis of the chemical and physical processes of clinker formation, a heat flux function was introduced to take account of the thermal effect of clinker formation. Combining the models of gas-solid flow, heat and mass transfer, and pulverized coal combustion, a set of mathematical models for a full-scale cement rotary kiln were established. In terms of commercial CFD code (FLUENT), the distributions of gas velocity, gas temperature, and gas components in a cement rot...

  13. Measure Guideline: Combustion Safety for Natural Draft Appliances Using Indoor Air

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L. [Partnership for Advanced Residential Retrofit, Des Plaines, IL (United States)

    2014-04-01

    This measure guideline covers how to assess and carry out the combustion safety procedures for appliances and heating equipment that uses indoor air for combustion in low-rise residential buildings. Only appliances installed in the living space, or in an area freely communicating with the living space, vented alone or in tandem with another appliance are considered here. A separate measure guideline addresses combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage that use outdoor air for combustion. This document is for inspectors, auditors, and technicians working in homes where energy upgrades are being conducted whether or not air infiltration control is included in the package of measures being applied. In the indoor combustion air case, guidelines summarized here are based on language provided in several of the codes to establish minimum requirements for the space using simplified prescriptive measures. In addition, building performance testing procedures are provided by testing agencies. The codes in combination with the test procedures offer comprehensive combustion safety coverage to address safety concerns, allowing inexperienced residential energy retrofit inspectors to effectively address combustion safety issues and allow energy retrofits to proceed.

  14. Space Time Codes from Permutation Codes

    CERN Document Server

    Henkel, Oliver

    2006-01-01

    A new class of space time codes with high performance is presented. The code design utilizes tailor-made permutation codes, which are known to have large minimal distances as spherical codes. A geometric connection between spherical and space time codes has been used to translate them into the final space time codes. Simulations demonstrate that the performance increases with the block lengths, a result that has been conjectured already in previous work. Further, the connection to permutation codes allows for moderate complex en-/decoding algorithms.

  15. The first turbulent combustion

    CERN Document Server

    Gibson, C H

    2005-01-01

    The first turbulent combustion arises in a hot big bang cosmological model Gibson (2004) where nonlinear exothermic turbulence permitted by quantum mechanics, general relativity, multidimensional superstring theory, and fluid mechanics cascades from Planck to strong force freeze out scales with gravity balancing turbulent inertial-vortex forces. Interactions between Planck scale spinning and non-spinning black holes produce high Reynolds number turbulence and temperature mixing with huge Reynolds stresses driving the rapid inflation of space. Kolmogorovian turbulent temperature patterns are fossilized as strong-force exponential inflation stretches them beyond the scale of causal connection ct where c is light speed and t is time. Fossil temperature turbulence patterns seed nucleosynthesis, and then hydro-gravitational structure formation in the plasma epoch, Gibson (1996, 2000). Evidence about formation mechanisms is preserved by cosmic microwave background temperature anisotropies. CMB spectra indicate hydr...

  16. Fundamentals of convolutional coding

    CERN Document Server

    Johannesson, Rolf

    2015-01-01

    Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual

  17. Filtration combustion: Smoldering and SHS

    Science.gov (United States)

    Matkowsky, Bernard J.

    1995-01-01

    Smolder waves and SHS (self-propagating high-temperature synthesis) waves are both examples of combustion waves propagating in porous media. When delivery of reactants through the pores to the reaction site is an important aspect of the process, it is referred to as filtration combustion. The two types of filtration combustion have a similar mathematical formulation, describing the ignition, propagation and extinction of combustion waves in porous media. The goal in each case, however, is different. In smoldering the desired goal is to prevent propagation, whereas in SHS the goal is to insure propagation of the combustion wave, leading to the synthesis of desired products. In addition, the scales in the two areas of application may well differ. For example, smoldering generally occurs at a relatively low temperature and with a smaller propagation velocity than SHS filtration combustion waves. Nevertheless, the two areas of application have much in common, so that mechanisms learned about in one application can be used to advantage in the other. In this paper we discuss recent results in the areas of filtration combustion.

  18. Combustion Properties of Straw Briquettes

    Directory of Open Access Journals (Sweden)

    Zhao Qing-ling

    2013-05-01

    Full Text Available The low bulk density of straw is one of the major barriers, which blocks the collection, handling, transportation and storage. Densification of biomass into briquettes/pellets is a suitable method of increasing the bulk density of biomass. Yet in the process, a tremendous amount of air is ejected from biomass grind, which brings substantial specific variation including combustion property. Among them, combustion property is critical for proper design and operation of burning facilities. Therefore, a series of tests about combustion properties of 75mm diameter corn briquettes were done. First, the combustion process (ignition, full flaming and glowing phases., precipitation of tar were investigated by a heating stove, then, Some ash sample from the muffle burner was subjected to an ash melting characteristic test. The results show the combustion of briquettes takes more time than that of raw straw from ignition to complete combustion; in order to meet complete combustion in a short time, the raw straw needs more supply air volume than briquettes under the same α value; the temperature of furnace chamber should been controlled under 900°C, which help to reduce the dark smoke, tar and slag.

  19. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  20. Improved Stiff ODE Solvers for Combustion CFD

    Science.gov (United States)

    Imren, A.; Haworth, D. C.

    2016-11-01

    Increasingly large chemical mechanisms are needed to predict autoignition, heat release and pollutant emissions in computational fluid dynamics (CFD) simulations of in-cylinder processes in compression-ignition engines and other applications. Calculation of chemical source terms usually dominates the computational effort, and several strategies have been proposed to reduce the high computational cost associated with realistic chemistry in CFD. Central to most strategies is a stiff ordinary differential equation (ODE) solver to compute the change in composition due to chemical reactions over a computational time step. Most work to date on stiff ODE solvers for computational combustion has focused on backward differential formula (BDF) methods, and has not explicitly considered the implications of how the stiff ODE solver couples with the CFD algorithm. In this work, a fresh look at stiff ODE solvers is taken that includes how the solver is integrated into a turbulent combustion CFD code, and the advantages of extrapolation-based solvers in this regard are demonstrated. Benefits in CPU time and accuracy are demonstrated for homogeneous systems and compression-ignition engines, for chemical mechanisms that range in size from fewer than 50 to more than 7,000 species.

  1. On Lean Turbulent Combustion Modeling

    Directory of Open Access Journals (Sweden)

    Constantin LEVENTIU

    2014-06-01

    Full Text Available This paper investigates a lean methane-air flame with different chemical reaction mechanisms, for laminar and turbulent combustion, approached as one and bi-dimensional problem. The numerical results obtained with Cantera and Ansys Fluent software are compared with experimental data obtained at CORIA Institute, France. First, for laminar combustion, the burn temperature is very well approximated for all chemical mechanisms, however major differences appear in the evaluation of the flame front thickness. Next, the analysis of turbulence-combustion interaction shows that the numerical predictions are suficiently accurate for small and moderate turbulence intensity.

  2. Regulation possibilities of biomass combustion

    Science.gov (United States)

    Suzdalenko, Vera; Gedrovics, Martins; Zake, Maija; Barmina, Inesa

    2012-11-01

    The focus of the recent experimental research is to analyze the regulation possibilities of biomass combustion. Three possibilities were chosen as part of this research: a) biomass cofiring with propane, b) swirling flow with re-circulation zone, and c) use of a permanent magnet. The aim of the research is to provide stable, controllable and effective biomass combustion with minimum emissions. The special pilot device was created where biomass can be combusted separately and co-fired with propane. Wood pellets were used during the experiments.

  3. Combustion-gas recirculation system

    Science.gov (United States)

    Baldwin, Darryl Dean

    2007-10-09

    A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

  4. THE COMBUSTION ACTION VERIFICATION AND ESTIMATE OF COMBUSTION EFFICIENCY IN AVIATION GAS#TURBINE ENGINE COMBUSTION CHAMBERS

    OpenAIRE

    2011-01-01

    Verification results of combustion action simulating and estimate of calculation combustion efficiency that was given by simulating were shown. Mathematical model and its assumption are described. Execution calculations method was shown. Results of simulating are shown; their comparative analyses with results of experiment were executed. Accuracy of combustion action mathematical modeling by combustion efficiency in model with oneand two-stage reactions of combustion was estimated. The infere...

  5. Measures for a quality combustion (combustion chamber exit and downstream); Mesures pour une combustion de qualite (sortie de chambre de combustion et en aval)

    Energy Technology Data Exchange (ETDEWEB)

    Epinat, G. [APAVE Lyonnaise, 69 (France)

    1996-12-31

    After a review of the different pollutants related to the various types of stationary and mobile combustion processes (stoichiometric, reducing and oxidizing combustion), measures and analyses than may be used to ensure the quality and efficiency of combustion processes are reviewed: opacimeters, UV analyzers, etc. The regulation and control equipment for combustion systems are then listed, according to the generator capacity level

  6. Computational Modeling of Turbulent Spray Combustion

    NARCIS (Netherlands)

    Ma, L.

    2016-01-01

    The objective of the research presented in this thesis is development and validation of predictive models or modeling approaches of liquid fuel combustion (spray combustion) in hot-diluted environments, known as flameless combustion or MILD combustion. The goal is to combine good physical insight,

  7. Computational Modeling of Turbulent Spray Combustion

    NARCIS (Netherlands)

    Ma, L.

    2016-01-01

    The objective of the research presented in this thesis is development and validation of predictive models or modeling approaches of liquid fuel combustion (spray combustion) in hot-diluted environments, known as flameless combustion or MILD combustion. The goal is to combine good physical insight, a

  8. Multiuser Cooperation with Hybrid Network Coding in Wireless Networks

    Directory of Open Access Journals (Sweden)

    G. Wang

    2014-04-01

    Full Text Available In this paper a hybrid Network Coding Cooperation (hybrid-NCC system is proposed to achieve both reliable transmission and high throughput in wireless networks. To balance the transmission reliability with throughput, the users are divided into cooperative sub-networks based on the geographical information, and the cooperation is implemented in each sub-network. After receiving signals from the cooperative partners, each user encodes them by exploiting hybrid network coding and then forwards the recoded symbols via the Link-Adaptive Regenerative (LAR relaying. First, the Diversity-Multiplexing Tradeoff (DMT is analyzed to demonstrate that the proposed system is bandwidth-efficient. Second, the Symbol Error Probability (SEP is also derived, which shows that the proposed system achieves a higher reliability as compared to the traditional Complex Field Network Coding Cooperation (CFNCC. Moreover, because dedicated relays are not required, our proposed system can both reduce the costs and enhance the flexibility of the implementation. Finally, the analytical results are supported and validated by numerical simulations.

  9. Strong Trinucleotide Circular Codes

    Directory of Open Access Journals (Sweden)

    Christian J. Michel

    2011-01-01

    Full Text Available Recently, we identified a hierarchy relation between trinucleotide comma-free codes and trinucleotide circular codes (see our previous works. Here, we extend our hierarchy with two new classes of codes, called DLD and LDL codes, which are stronger than the comma-free codes. We also prove that no circular code with 20 trinucleotides is a DLD code and that a circular code with 20 trinucleotides is comma-free if and only if it is a LDL code. Finally, we point out the possible role of the symmetric group ∑4 in the mathematical study of trinucleotide circular codes.

  10. Northampton Community College Adult Learner Competencies Implementation. Final Report, 1998-1999 [and] Adult Learner Competencies Implementation Manual for Workshops #1 and #2 and NCC Competencies-Based Lesson Plan "Mini-Bank".

    Science.gov (United States)

    Sullivan, Judy

    A project provided training and guidance to Northampton Community College (NCC) staff in implementing the "new" adult learner skill competencies. Two workshops were held to serve 29 staff in Monroe, Wayne, and Pike counties in Pennsylvania. Among the topics covered were defining and introducing portfolios to adult learners, individualizing…

  11. Joint source channel coding using arithmetic codes

    CERN Document Server

    Bi, Dongsheng

    2009-01-01

    Based on the encoding process, arithmetic codes can be viewed as tree codes and current proposals for decoding arithmetic codes with forbidden symbols belong to sequential decoding algorithms and their variants. In this monograph, we propose a new way of looking at arithmetic codes with forbidden symbols. If a limit is imposed on the maximum value of a key parameter in the encoder, this modified arithmetic encoder can also be modeled as a finite state machine and the code generated can be treated as a variable-length trellis code. The number of states used can be reduced and techniques used fo

  12. Combustion Process Modelling and Control

    Directory of Open Access Journals (Sweden)

    Vladimír Maduda

    2007-10-01

    Full Text Available This paper deals with realization of combustion control system on programmable logic controllers. Control system design is based on analysis of the current state of combustion control systems in technological device of raw material processing area. Control system design is composed of two subsystems. First subsystem is represented by software system for measured data processing and for data processing from simulation of the combustion mathematical model. Outputs are parameters for setting of controller algorithms. Second subsystem consists from programme modules. The programme module is presented by specific control algorithm, for example proportional regulation, programmed proportional regulation, proportional regulation with correction on the oxygen in waste gas, and so on. According to the specific combustion control requirements it is possible built-up concrete control system by programme modules. The programme modules were programmed by Automation studio that is used for development, debugging and testing software for B&R controllers.

  13. Putting combustion optimization to work

    Energy Technology Data Exchange (ETDEWEB)

    Spring, N.

    2009-05-15

    New plants and plants that are retrofitting can benefit from combustion optimization. Boiler tuning and optimization can complement each other. The continuous emissions monitoring system CEMS, and tunable diode laser absorption spectroscopy TDLAS can be used for optimisation. NeuCO's CombustionOpt neural network software can determine optimal fuel and air set points. Babcock and Wilcox Power Generation Group Inc's Flame Doctor can be used in conjunction with other systems to diagnose and correct coal-fired burner performance. The four units of the Colstrip power plant in Colstrips, Montana were recently fitted with combustion optimization systems based on advanced model predictive multi variable controls (MPCs), ABB's Predict & Control tool. Unit 4 of Tampa Electric's Big Bend plant in Florida is fitted with Emerson's SmartProcess fuzzy neural model based combustion optimisation system. 1 photo.

  14. Flameless Combustion for Gas Turbines

    Science.gov (United States)

    Gutmark, Ephraim; Li, Guoqiang; Overman, Nick; Cornwell, Michael; Stankovic, Dragan; Fuchs, Laszlo; Milosavljevic, Vladimir

    2006-11-01

    An experimental study of a novel flameless combustor for gas turbine engines is presented. Flameless combustion is characterized by distributed flame and even temperature distribution for high preheat air temperature and large amount of recirculating low oxygen exhaust gases. Extremely low emissions of NOx, CO, and UHC are reported. Measurements of the flame chemiluminescence, CO and NOx emissions, acoustic pressure, temperature and velocity fields as a function of the preheat temperature, inlet air mass flow rate, exhaust nozzle contraction ratio, and combustor chamber diameter are described. The data indicate that larger pressure drop promotes flameless combustion and low NOx emissions at the same flame temperature. High preheated temperature and flow rates also help in forming stable combustion and therefore are favorable for flameless combustion.

  15. Combustion aerosols from potassium-containing fuels

    Energy Technology Data Exchange (ETDEWEB)

    Balzer Nielsen, Lars

    1998-12-31

    The scope of the work presented in this thesis is the formation and evolution of aerosol particles in the submicron range during combustion processes, in particular where biomass is used alone or co-fired with coal. An introduction to the formation processes of fly ash in general and submicron aerosol in particular during combustion is presented, along with some known problems related to combustion of biomass for power generation. The work falls in two parts. The first is the design of a laboratory setup for investigation of homogeneous nucleation and particle dynamics at high temperature. The central unit of the setup is a laminar flow aerosol condenser (LFAC), which essentially is a 173 cm long tubular furnace with an externally cooled wall. A mathematical model is presented which describes the formation and evolution of the aerosol in the LFAC, where the rate of formation of new nuclei is calculated using the so-called classical theory. The model includes mass and energy conservation equations and an expression for the description of particle growth by diffusion. The resulting set of nonlinear second-order partial differential equations are solved numerically using the method of orthogonal collocation. The model is implemented in the FORTRAN code MONAERO. The second part of this thesis describes a comprehensive investigation of submicron aerosol formation during co-firing of coal and straw carried out at a 380 MW{sub Th} pulverized coal unit at Studstrup Power Plant, Aarhus. Three types of coal are used, and total boiler load and straw input is varied systematically. Straw contains large amounts of potassium, which is released during combustion. Submicron aerosol is sampled between the two banks of the economizer at a flue gas temperature of 350 deg. C using a novel ejector probe. The aerosol is characterized using the SMPS system and a Berner-type low pressure impactor. The chemical composition of the particles collected in the impactor is determined using

  16. Combustion of boron containing compositions

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, Y.; Pivkina, A. [Institute of Chemical Physics, Russian Academy of Science, Moscow (Russian Federation)

    1996-12-31

    Boron is one of the most energetic components for explosives, propellants and for heterogeneous condensed systems in common. The combustion process of mixtures of boron with different oxidizers was studied. The burning rate, concentration combustion limits, the agglomeration and dispersion processes during reaction wave propagation were analysed in the respect of the percolation theory. The linear dependence of the burning rate on the contact surface value was demonstrated. The percolative model for the experimental results explanation is proposed. (authors) 5 refs.

  17. Smoldering Combustion Experiments in Microgravity

    Science.gov (United States)

    Walther, David C.; Fernandez-Pello, A. Carlos; Urban, David L.

    1997-01-01

    The Microgravity Smoldering Combustion (MSC) experiment is part of a study of the smolder characteristics of porous combustible materials in a microgravity environment. Smoldering is a non-flaming form of combustion that takes place in the interior of porous materials and takes place in a number of processes ranging from smoldering of porous insulation materials to high temperature synthesis of metals. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder, both in microgravity and normal-gravity. As with many forms of combustion, gravity affects the availability of oxidizer and transport of heat, and therefore the rate of combustion. Microgravity smolder experiments, in both a quiescent oxidizing environment, and in a forced oxidizing flow have been conducted aboard the NASA Space Shuttle (STS-69 and STS-77 missions) to determine the effect of the ambient oxygen concentration and oxidizer forced flow velocity on smolder combustion in microgravity. The experimental apparatus is contained within the NASA Get Away Special Canister (GAS-CAN) Payload. These two sets of experiments investigate the propagation of smolder along the polyurethane foam sample under both diffusion driven and forced flow driven smoldering. The results of the microgravity experiments are compared with identical ones carried out in normal gravity, and are used to verify present theories of smolder combustion. The results of this study will provide new insights into the smoldering combustion process. Thermocouple histories show that the microgravity smolder reaction temperatures (Ts) and propagation velocities (Us) lie between those of identical normal-gravity upward and downward tests. These observations indicate the effect of buoyancy on the transport of oxidizer to the reaction front.

  18. Molecular insights from dysregulation of the thiazide-sensitive WNK/SPAK/NCC pathway in the kidney: Gordon syndrome and thiazide-induced hyponatraemia.

    Science.gov (United States)

    Glover, Mark; O'Shaughnessy, Kevin M

    2013-12-01

    Human blood pressure is dependent on balancing dietary salt intake with its excretion by the kidney. Mendelian syndromes of altered blood pressure demonstrate the importance of the distal nephron in this process and of the thiazide-sensitive pathway in particular. Gordon syndrome (GS), the phenotypic inverse of the salt-wasting Gitelman syndrome, is a condition of hyperkalaemic hypertension that is reversed by low-dose thiazide diuretics or a low-salt diet. Variants within at least four genes [i.e. with-no-lysine(K) kinase 1 (WNK1), WNK4, kelch-like family member 3 (KLHL3) and cullin 3 (CUL3)] can cause the phenotype of GS. Details are still emerging for some of these genes, but it is likely that they all cause a gain-of-function in the thiazide-sensitive Na(+) -Cl(-) cotransporter (NCC) and hence salt retention. Herein, we discuss the key role of STE20/sporulation-specific protein 1 (SPS1)-related proline/alanine-rich kinase (SPAK), which functions as an intermediary between the WNKs and NCC and for which a loss-of-function mutation produces a Gitelman-type phenotype in a mouse model. In addition to Mendelian blood pressure syndromes, the study of patients who develop thiazide-induced-hyponatraemia (TIH) may give further molecular insights into the role of the thiazide-sensitive pathway for salt reabsorption. In the present paper we discuss the key features of TIH, including its high degree of reproducibility on rechallenge, possible genetic predisposition and mechanisms involving excessive saliuresis and water retention. Together, studies of Gordon syndrome and TIH may increase our understanding of the molecular regulation of sodium trafficking via the thiazide-sensitive pathway and have important implications for hypertensive patients, both in the identification of new antihypertensive drug targets and avoidance of hyponatraemic side-effects. © 2013 Wiley Publishing Asia Pty Ltd.

  19. 纳米纤维素/天然橡胶复合材料的制备及表征%Preparation and Characterization of Nano -crystalline Cellulose/Natural Rubber (NCC/NR) Composites *

    Institute of Scientific and Technical Information of China (English)

    陈红莲; 高天明; 黄茂芳; 廖建和

    2012-01-01

    Blended natural rubber (NR) with different amount of nano - cellulose cellulose ( NCC ) were usea to prepare nano -crystalline cellulose/natural rubber (NCC/NR) composites. The resulting products were characterized by scanning electron microscopy ( SEM), mechanical property testing, thermo - gravimetric analysis and dynamic mechanical analysis(DMA). Results showed that NCC were homogeneously distributed throughout NR matrix, which led to the en- hancement on mechanical properties. Moreover, the storage modulus ( E' ) of composites went up with the increment of NCC loadings and loss factor (tang) decreases, and the addition of NCC had less impact on the thermal stability of NR matrix.%采用共混法制备不同比率含量的纳米纤维素/天然橡胶(NCC/NR)复合材料,通过扫描电镜、力学性能、热稳定性以及动态力学性能的测定分析表明:纳米纤维素能较均匀分散在橡胶基质中,对天然橡胶起到较好的补强效果,复合材料的储能模量逐步增大,损耗因子逐步减小,纳米纤维素的加入对天然橡胶的热稳定性影响不大。

  20. Rotary internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Witkowski, J.

    1989-12-05

    This patent describes an internal combustion engine assembly. It includes: a central rotor means formed with at least one peripheral fuel cavity. The cavity having a first surface defining a thrust surface and a second surface defining a contoured surface; a housing means enclosing the rotor and having an internal wall encircling the rotor. The internal wall being intercepted by at least two recesses defining cylinder means. The housing means and the rotor means being relatively rotatable; piston means individual to each the cylinder means and reciprocable therein; each piton means having a working face complementary to aid contoured surface; and power means for urging the working face into intimate areal contact with the contoured surface to create a first seal means. The housing means having at lest one fuel inlet port, at least one fuel ignition means and at least one exhaust port whereby during the course of a revolution of the rotor means relative to the housing means, the first seal means, the power means, the respective ports, the ignition means and the fuel cavity cooperate to develop fuel compression, fuel ignition and exhaust functions.

  1. Internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Laskaris, M.A.; Broitman, K.; Natale, S.E.

    1991-08-27

    This patent describes improvement in a two-stroke internal combustion engine adapted to run on a diesel or a kerosene type of fuel, and including a piston connected to the crankshaft of the engine to move within a cylinder through a first stroke from a top dead center position to a bottom dead center position and through a second stroke from the bottom dead center position back to the top dead center position. The improvement comprises: means providing a cylinder head at the top end of the engine cylinder in the shape of an open bowl having a generally cup-shaped configuration including a sidewall portion, a spark plug positioned centrally within the bowl at the top end of the cylinder, and means for injecting fuel into the top end of the engine cylinder at a location between the spark plug and the sidewall portion, the fuel injecting means including an injection nozzle having a plurality of nozzle openings therein, the nozzle openings being constructed and arranged to discharge a plurality of plume-like sprays into the top end of the cylinder at a location within the bowl, two of the sprays being directed from the nozzle to diverge and pass along opposite sides of the spark plug, and additional sprays being directed from the nozzle against the sidewall portion or the cylinder head to be deflected therefrom back toward the piston and the spark plug to thereby form a cloud of fuel over the spark plug for good ignition.

  2. Model Children's Code.

    Science.gov (United States)

    New Mexico Univ., Albuquerque. American Indian Law Center.

    The Model Children's Code was developed to provide a legally correct model code that American Indian tribes can use to enact children's codes that fulfill their legal, cultural and economic needs. Code sections cover the court system, jurisdiction, juvenile offender procedures, minor-in-need-of-care, and termination. Almost every Code section is…

  3. Approach to the calculation of energy deposition in a container of fuel irradiated by the neutronic codes coupling fluid-dynamics; Aprpoximacion al calculo de la deposicion energetica en un contenedor de combustible irradiado mediante el acoplamiento de codigos neutronico fluido-dinamicos

    Energy Technology Data Exchange (ETDEWEB)

    Hueso, C.; Aleman, A.; Colomer, C.; Fabbri, M.; Martin, M.; Saellas, J.

    2013-07-01

    In this work identifies a possible area of improvement through the creation of a code of coupling between deposition energy codes which calculate neutron (MCNP), and data from heading into fluid dynamics (ANSYS-Fluent) or codes thermomechanical, called MAFACS (Monte Carlo ANSYS Fluent Automatic Coupling Software), being possible to so summarize the process by shortening the needs of computing time, increasing the precision of the results and therefore improving the design of the components.

  4. Effect of Pilot Injection Timings on the Combustion Temperature Distribution in a Single-Cylinder CI Engine Fueled with DME and ULSD

    National Research Council Canada - National Science Library

    Jeon, Joonho; Park, Yong Hee; Kwon, Sang Il; Park, Sungwook

    2016-01-01

    ... that there is no sooting flame in DME combustion. In order to investigate the combustion characteristics in this study, the KIVA-3 V code was implemented to research various pilot injection strategies on a single-cylinder CI engines with DME...

  5. Transformations of inorganic coal constituents in combustion systems. Volume 3, Appendices: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. [ed.; Srinivasachar, S.; Wilemski, G.; Boni, A.A. [PSI Technology Co., Andover, MA (United States); Kang, Shim-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Peterson, T.W.; Wendt, O.L.; Gallagher, N.B.; Bool, L. [Arizona Univ., Tucson, AZ (United States); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. [Kentucky Univ., Lexington, KY (United States)

    1992-11-01

    This report contains the computer codes developed for the coal combustion project. In Subsection B.1 the FORTRAN code developed for the percolative fragmentation model (or the discrete model, since a char is expressed as a collection of discrete elements in a discrete space) is presented. In Subsection B.2 the code for the continuum model (thus named because mineral inclusions are distributed in a continuum space) is presented. A stereological model code developed to obtain the pore size distribution from a two-dimensional data is presented in Subsection B.3.

  6. Modelling combustion reactions for gas flaring and its resulting emissions

    Directory of Open Access Journals (Sweden)

    O. Saheed Ismail

    2016-07-01

    Full Text Available Flaring of associated petroleum gas is an age long environmental concern which remains unabated. Flaring of gas maybe a very efficient combustion process especially steam/air assisted flare and more economical than utilization in some oil fields. However, it has serious implications for the environment. This study considered different reaction types and operating conditions for gas flaring. Six combustion equations were generated using the mass balance concept with varying air and combustion efficiency. These equations were coded with a computer program using 12 natural gas samples of different chemical composition and origin to predict the pattern of emission species from gas flaring. The effect of key parameters on the emission output is also shown. CO2, CO, NO, NO2 and SO2 are the anticipated non-hydrocarbon emissions of environmental concern. Results show that the quantity and pattern of these chemical species depended on percentage excess/deficiency of stoichiometric air, natural gas type, reaction type, carbon mass content, impurities, combustion efficiency of the flare system etc. These emissions degrade the environment and human life, so knowing the emission types, pattern and flaring conditions that this study predicts is of paramount importance to governments, environmental agencies and the oil and gas industry.

  7. Computational modeling of high pressure combustion mechanism in scram accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.Y. [Pusan Nat. Univ. (Korea); Lee, B.J. [Pusan Nat. Univ. (Korea); Agency for Defense Development, Taejon (Korea); Jeung, I.S. [Pusan Nat. Univ. (Korea); Seoul National Univ. (Korea). Dept. of Aerospace Engineering

    2000-11-01

    A computational study was carried out to analyze a high-pressure combustion in scram accelerator. Fluid dynamic modeling was based on RANS equations for reactive flows, which were solved in a fully coupled manner using a fully implicit-upwind TVD scheme. For the accurate simulation of high-pressure combustion in ram accelerator, 9-species, 25-step fully detailed reaction mechanism was incorporated with the existing CFD code previously used for the ram accelerator studies. The mechanism is based on GRI-Mech. 2.11 that includes pressure-dependent reaction rate formulations indispensable for the correct prediction of induction time in high-pressure environment. A real gas equation of state was also included to account for molecular interactions and real gas effects of high-pressure gases. The present combustion modeling is compared with previous 8-step and 19-step mechanisms with ideal gas assumption. The result shows that mixture ignition characteristics are very sensitive to the combustion mechanisms, and different mechanism results in different reactive flow-field characteristics that have a significant relevance to the operation mode and the performance of scram accelerator. (orig.)

  8. Liquid propellant rocket engine combustion simulation with a time-accurate CFD method

    Science.gov (United States)

    Chen, Y. S.; Shang, H. M.; Liaw, Paul; Hutt, J.

    1993-01-01

    Time-accurate computational fluid dynamics (CFD) algorithms are among the basic requirements as an engineering or research tool for realistic simulations of transient combustion phenomena, such as combustion instability, transient start-up, etc., inside the rocket engine combustion chamber. A time-accurate pressure based method is employed in the FDNS code for combustion model development. This is in connection with other program development activities such as spray combustion model development and efficient finite-rate chemistry solution method implementation. In the present study, a second-order time-accurate time-marching scheme is employed. For better spatial resolutions near discontinuities (e.g., shocks, contact discontinuities), a 3rd-order accurate TVD scheme for modeling the convection terms is implemented in the FDNS code. Necessary modification to the predictor/multi-corrector solution algorithm in order to maintain time-accurate wave propagation is also investigated. Benchmark 1-D and multidimensional test cases, which include the classical shock tube wave propagation problems, resonant pipe test case, unsteady flow development of a blast tube test case, and H2/O2 rocket engine chamber combustion start-up transient simulation, etc., are investigated to validate and demonstrate the accuracy and robustness of the present numerical scheme and solution algorithm.

  9. Experimental investigations and CFD study of temperature distribution during oscillating combustion in a crucible furnace

    Directory of Open Access Journals (Sweden)

    J. Govardhan, G.V.S. Rao, J. Narasaiah

    2011-09-01

    Full Text Available As part of an investigation few experiments were conducted to study the enhanced heat transfer rate and increased furnace efficiency in a diesel fired crucible furnace with oscillating combustion. The results of experimental investigations of temperature distribution inside the crucible furnace during oscillating combustion are validated with the numerical simulation CFD code. At first pragmatic study of temperature distribution inside a furnace was carried out with conventional mode of combustion at certain conditions and later transient behavior similar to that is conducted with oscillating combustion mode with the same conditions. There found to be enhanced heat transfer rate, reduced processing time and increased furnace efficiency with visibly clean emissions during the oscillating combustion mode than the conventional combustion mode. In the present paper the temperatures inside the furnace at few designated points measured by suitable K type thermo-couples are compared with the CFD code. The geometric models were created in ANSYS and the configuration was an asymmetric one for computational reason. The experimental and numerical investigations produce similar acceptable results. The presented results show that the 3D transient model appeared to be an effective numerical tool for the simulation of the crucible furnace for melting processes.

  10. Validation of CFD-models for non-stoichiometric oxycoal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, Jan-Peter; Goanta, Adrian; Baumgartner, Andreas; Blume, Maximilian; Spliethoff, Hartmut [Technische Univ. Muenchen, Garching (Germany). Inst. of Energy Systems

    2013-07-01

    To compensate the drawback of high flue gas recirculation rates specific for oxyfuel processes, a new concept based on staged combustion, called controlled staging with non-stoichiometric burners (CSNB) was investigated. A combination of over- and sub-stoichiometric burners avoids inadmissible high flame temperatures even with oxygen concentrations up to 40 vol.-% in the oxidant. The non-stoichiometric burners are arranged in such a way that the overall stoichiometry at the combustion chamber outlet is slightly over-stoichiometric similar to conventional combustion processes, so that full burn out is secured. This concept aims at a more efficient oxyfuel process due to the decreasing effort in the recirculation loop and a new designed, more cost effective, steam generator. For further process optimization of the CSNB concept and the adjacent steam generator layout are validated CFD simulations urgently required. This paper shows first steps in validation of the CSNB combustion concept against state of the art CFD codes. The CFD code was optimized for oxyfuel combustion including a new char combustion and gas radiation model. Experimental investigations and CFD modelling are showing good agreement in concerns of temperature, CO and CO{sub 2} profiles. However the prediction of the oxygen concentration differs significantly between experiment and simulation.

  11. Modelling of turbulent combustion in the blast furnace raceway

    Energy Technology Data Exchange (ETDEWEB)

    Karvinen, R.; Maekiranta, R. [Tampere Univ. (Finland). Energy and Process Engineering

    1996-12-31

    The phenomena concerning coke-gas -suspension and simultaneous combustion of solid coke particles and residual fuel oil in a blast furnace raceway are modelled. The flow field of suspension is predicted by using the two fluid model, which is based on the Eulerian method, in the Phoenics code. The standard k-e -model of turbulence is used. Pyrolysis of oil droplets is calculated with the own coded subroutine, which is based on the Lagrangian approach. Gas phase reaction rate is assumed to be controlled by chemical kinetics. Radiative heat transfer is calculated by using the six-flux method. Heterogenous surface reactions are used for the coke particles. Calculations without coke combustion show that due to a poor mixing in the hot blast, pyrolysis gases of residual fuel oil have not time enough to react with oxygen. It is obvious that if combustion of coke particles is taken into account, the oxygen content in the blast decreases to such a level, that unburnt pyrolysis gases can flow out of the raceway causing problems. The distribution of coke void fraction has been succeeded to predict in the raceway domain. Coke particles fall from the upper part of the raceway to the hot blast forming locally high concentrations, which affect very strongly the oxygen distribution of the hot blast. (orig.) SULA 2 Research Programme; 10 refs.

  12. Twenty-second symposium (international) on combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The following research areas were discussed at the symposium: coal combustion: carbon burnout, pyrolysis, furnaces, laboratory-scale combustion, and fluidized bed combustion; combustion-generated particulates: soot inception, growth, and soot formation in diffusion flames; engine combustion; turbulent combustion: flames in vortices, fractals and cellular automations, nonpremixed flames, premixed flames, premixed flame structure, and lifted flames; reaction kinetics: hydrocarbon oxidation, free radical chemistry, unsaturated species, aromatics, and nitrogen compounds/pollutant formation; combustion generated NO/sub x/ and SO/sub x/; fires: flame spread, radiation, characterization, and unsteady flames; Laminar flames: structure, opposed-flow combustion, shape, propagation/extinction, and inhibition, oscillations, microgravity; ignition; detonations; dusts; propellants; diagnostics; combustion of drops, sprays, and dispersions, and slurries. Individual projects are processed separately for the data bases. (CBS)

  13. Development and validation of mathematical modelling for pressurised combustion

    Energy Technology Data Exchange (ETDEWEB)

    Richter, S.; Knaus, H.; Risio, B.; Schnell, U.; Hein, K.R.G. [University of Stuttgart, Stuttgart (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1998-12-31

    The advanced 3D-coal combustion code AIOLOS for quasi-stationary turbulent reacting flows is based on a conservative finite-volume procedure. Equations for the conservation of mass, momentum and scalar quantities are solved. In order to deal with pressurized combustion chambers which are usually of cylindrical shape, a first task in the frame of the project consisted in the extension of the code towards cylindrical co-ordinates, since the basic version of AIOLOS was only suitable for cartesian grids. Furthermore, the domain decomposition method was extended to the new co-ordinate system. Its advantage consists in the possibility to introduce refined sub-grids, providing a better resolution of regions where high gradients occur (e.g. high velocity and temperature gradients near the burners). The accuracy of the code was proven by means of a small-scale test case. The results obtained with AIOLOS were compared with the predictions of the commercial CFD-code FLOW3D and validated against the velocity and temperature distributions measured at the test facility. The work during the second period focused mainly on the extension of the reaction model, as well as on the modelling of the optical properties of the flue gas. A modified submodel for char burnout was developed, considering the influence of pressure on diffusion mechanisms and on the chemical reaction at the char particle. The goal during the third project period was to improve the numerical description of turbulence effects and of the radiative heat transfer, in order to obtain an adequate modelling of the complex processes in pressurized coal combustion furnaces. Therefore, a differential Reynolds stress turbulence model (RSM) and a Discrete-Ordinates radiation model were implemented, respectively. 13 refs., 13 figs., 1 tab.

  14. Combustion iron distribution and deposition

    Science.gov (United States)

    Luo, Chao; Mahowald, N.; Bond, T.; Chuang, P. Y.; Artaxo, P.; Siefert, R.; Chen, Y.; Schauer, J.

    2008-03-01

    Iron is hypothesized to be an important micronutrient for ocean biota, thus modulating carbon dioxide uptake by the ocean biological pump. Studies have assumed that atmospheric deposition of iron to the open ocean is predominantly from mineral aerosols. For the first time we model the source, transport, and deposition of iron from combustion sources. Iron is produced in small quantities during fossil fuel burning, incinerator use, and biomass burning. The sources of combustion iron are concentrated in the industrialized regions and biomass burning regions, largely in the tropics. Model results suggest that combustion iron can represent up to 50% of the total iron deposited, but over open ocean regions it is usually less than 5% of the total iron, with the highest values (ocean biogeochemistry the bioavailability of the iron is important, and this is often estimated by the fraction which is soluble (Fe(II)). Previous studies have argued that atmospheric processing of the relatively insoluble Fe(III) occurs to make it more soluble (Fe(II)). Modeled estimates of soluble iron amounts based solely on atmospheric processing as simulated here cannot match the variability in daily averaged in situ concentration measurements in Korea, which is located close to both combustion and dust sources. The best match to the observations is that there are substantial direct emissions of soluble iron from combustion processes. If we assume observed soluble Fe/black carbon ratios in Korea are representative of the whole globe, we obtain the result that deposition of soluble iron from combustion contributes 20-100% of the soluble iron deposition over many ocean regions. This implies that more work should be done refining the emissions and deposition of combustion sources of soluble iron globally.

  15. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    The Combustion Byproducts Recycling Consortium (CBRC) program was developed as a focused program to remove and/or minimize the barriers for effective management of over 123 million tons of coal combustion byproducts (CCBs) annually generated in the USA. At the time of launching the CBRC in 1998, about 25% of CCBs were beneficially utilized while the remaining was disposed in on-site or off-site landfills. During the ten (10) year tenure of CBRC (1998-2008), after a critical review, 52 projects were funded nationwide. By region, the East, Midwest, and West had 21, 18, and 13 projects funded, respectively. Almost all projects were cooperative projects involving industry, government, and academia. The CBRC projects, to a large extent, successfully addressed the problems of large-scale utilization of CCBs. A few projects, such as the two Eastern Region projects that addressed the use of fly ash in foundry applications, might be thought of as a somewhat smaller application in comparison to construction and agricultural uses, but as a novel niche use, they set the stage to draw interest that fly ash substitution for Portland cement might not attract. With consideration of the large increase in flue gas desulfurization (FGD) gypsum in response to EPA regulations, agricultural uses of FGD gypsum hold promise for large-scale uses of a product currently directed to the (currently stagnant) home construction market. Outstanding achievements of the program are: (1) The CBRC successfully enhanced professional expertise in the area of CCBs throughout the nation. The enhanced capacity continues to provide technology and information transfer expertise to industry and regulatory agencies. (2) Several technologies were developed that can be used immediately. These include: (a) Use of CCBs for road base and sub-base applications; (b) full-depth, in situ stabilization of gravel roads or highway/pavement construction recycled materials; and (c) fired bricks containing up to 30%-40% F

  16. Rateless feedback codes

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip

    2012-01-01

    This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....

  17. Coding for dummies

    CERN Document Server

    Abraham, Nikhil

    2015-01-01

    Hands-on exercises help you learn to code like a pro No coding experience is required for Coding For Dummies,your one-stop guide to building a foundation of knowledge inwriting computer code for web, application, and softwaredevelopment. It doesn't matter if you've dabbled in coding or neverwritten a line of code, this book guides you through the basics.Using foundational web development languages like HTML, CSS, andJavaScript, it explains in plain English how coding works and whyit's needed. Online exercises developed by Codecademy, a leading online codetraining site, help hone coding skill

  18. Advanced video coding systems

    CERN Document Server

    Gao, Wen

    2015-01-01

    This comprehensive and accessible text/reference presents an overview of the state of the art in video coding technology. Specifically, the book introduces the tools of the AVS2 standard, describing how AVS2 can help to achieve a significant improvement in coding efficiency for future video networks and applications by incorporating smarter coding tools such as scene video coding. Topics and features: introduces the basic concepts in video coding, and presents a short history of video coding technology and standards; reviews the coding framework, main coding tools, and syntax structure of AV

  19. Piston surface heat transfer during combustion in large marine diesel engines

    DEFF Research Database (Denmark)

    Jensen, Michael Vincent; Walther, Jens Honore

    2010-01-01

    limited. The numerical investigation focused on the simulation of a hot turbulent gas jet impinging on a wall under very high pressure, thus approximating the process of the actual impingement of hot combustion gasses on the piston surface during combustion. The surface heat flux at the wall......In the design process of large marine diesel engines information on the maximum heat load on the piston surface experienced during the engine cycle is an important parameter. The peak heat load occurs during combustion when hot combustion products impinge on the piston surface. Although the maximum...... instrumentation and high engine running costs compared to automotive engines. Therefore the investigation in this work was carried out numerically with the use of a computational fluid dynamics (CFD) code. At the same time, numerical work on detailed in-cylinder wall heat transfer in engines has been quite...

  20. Turbulent Combustion in SDF Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, A L; Bell, J B; Beckner, V E

    2009-11-12

    A heterogeneous continuum model is proposed to describe the dispersion and combustion of an aluminum particle cloud in an explosion. It combines the gas-dynamic conservation laws for the gas phase with a continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models. It incorporates a combustion model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the C-4 booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Numerical simulations of the explosion fields from 1.5-g Shock-Dispersed-Fuel (SDF) charge in a 6.6 liter calorimeter were used to validate the combustion model. Then the model was applied to 10-kg Al-SDF explosions in a an unconfined height-of-burst explosion. Computed pressure histories are compared with measured waveforms. Differences are caused by physical-chemical kinetic effects of particle combustion which induce ignition delays in the initial reactive blast wave and quenching of reactions at late times. Current simulations give initial insights into such modeling issues.

  1. Explosion limits for combustible gases

    Institute of Scientific and Technical Information of China (English)

    TONG Min-ming; WU Guo-qing; HAO Ji-fei; DAI Xin-lian

    2009-01-01

    Combustible gases in coal mines are composed of methane, hydrogen, some multi-carbon alkane gases and other gases. Based on a numerical calculation, the explosion limits of combustible gases were studied, showing that these limits are related to the concentrations of different components in the mixture. With an increase of C4H10 and C6H14, the Lower ExplosionLimit (LEL) and Upper Explosion-Limit (UEL) of a combustible gas mixture will decrease clearly. For every 0.1% increase in C4H10 and C6H14, the LEL decreases by about 0.19% and the UEL by about 0.3%. The results also prove that, by increasing the amount of H2, the UEL of a combustible gas mixture will increase considerably. If the level of H2 increases by 0.1%, the UEL will increase by about 0.3%. However, H2 has only a small effect on the LEL of the combustible gas mixture. Our study provides a theoretical foundation for judging the explosion risk of an explosive gas mixture in mines.

  2. Validation of system codes for plant application on selected experiments

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Marco K.; Risken, Tobias; Agethen, Kathrin; Bratfisch, Christoph [Bochum Univ. (Germany). Reactor Simulation and Safety Group

    2016-05-15

    For decades, the Reactor Simulation and Safety Group at Ruhr-Universitaet Bochum (RUB) contributes to nuclear safety by computer code validation and model development for nuclear safety analysis. Severe accident analysis codes are relevant tools for the understanding and the development of accident management measures. The accidents in the plants Three Mile Island (USA) in 1979 and Fukushima Daiichi (Japan) in 2011 influenced these research activities significantly due to the observed phenomena, such as molten core concrete interaction and hydrogen combustion. This paper gives a brief outline of recent research activities at RUB in the named fields, contributing to code preparation for plant applications. Simulations of the molten core concrete interaction tests CCI-2 and CCI-3 with ASTEC and the hydrogen combustion test Ix9 with COCOSYS are presented exemplarily. Additionally, the application on plants is demonstrated on chosen results of preliminary Fukushima calculations.

  3. FDNS CFD Code Benchmark for RBCC Ejector Mode Operation

    Science.gov (United States)

    Holt, James B.; Ruf, Joe

    1999-01-01

    Computational Fluid Dynamics (CFD) analysis results are compared with benchmark quality test data from the Propulsion Engineering Research Center's (PERC) Rocket Based Combined Cycle (RBCC) experiments to verify fluid dynamic code and application procedures. RBCC engine flowpath development will rely on CFD applications to capture the multi-dimensional fluid dynamic interactions and to quantify their effect on the RBCC system performance. Therefore, the accuracy of these CFD codes must be determined through detailed comparisons with test data. The PERC experiments build upon the well-known 1968 rocket-ejector experiments of Odegaard and Stroup by employing advanced optical and laser based diagnostics to evaluate mixing and secondary combustion. The Finite Difference Navier Stokes (FDNS) code was used to model the fluid dynamics of the PERC RBCC ejector mode configuration. Analyses were performed for both Diffusion and Afterburning (DAB) and Simultaneous Mixing and Combustion (SMC) test conditions. Results from both the 2D and the 3D models are presented.

  4. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to Lactobacillus johnsonii NCC 533 (La1) (CNCM I-1225) and improving immune defence against pathogenic gastro-intestinal microorganisms (ID 896), and protection

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to Lactobacillus johnsonii NCC 533 (La1) (CNCM I-1225) and improving immune defence against pathogenic gastro-intestinal microorganisms, and protection of the skin from UV-induced damage. The scientific substantiation is based on the information provided by the Member States...... in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituent that is the subject of the health claim is Lactobacillus johnsonii NCC 533 (La1) (CNCM I-1225). The Panel considers that Lactobacillus johnsonii NCC 533 (La...

  5. New Combustion Regimes and Kinetic Studies of Plasma Assisted Combustion

    Science.gov (United States)

    2012-11-01

    Tasks 8 and 9: Kinetic model validation) Today’s Presentation 2. Multispecies diagnostics in a flow reactor with Mid-IR and molecular beam mass...S-Curve Competition between low T RO2 kinetics high T chain branching reactions 0.00 0.02 0.04 0.06 0.08 0.10 0.12 1x10 5 2x10 5 3x10 5 4x10...in Plasma assisted combustion • LTC in turbulent combustion at engine time scales 0-D modeling of DME /O2/He (0.03/0.1/0.896) ignition, P = 72

  6. INFLUENCE OF SWIRL ON SPRAY CHARACTERISTICS AND COMBUSTION, A NUMERICAL INVESTIGATION OF A CATERPILLER DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    M. SREENIVASULU

    2012-10-01

    Full Text Available The purpose of this study is to find the appropriate swirl ratio at which a DI diesel engine should be operated. In the process of identifying an appropriate swirl, the combustion behaviour was analysed by considering Pressure variations and Heat Release Rate variations against crank angle. The spray characteristics were also analysed by considering Penetration lengths, Sauter mean diameters, Spray cone angles against crank angle. Final conclusions were derived by considering NOx emission levels. A turbo charged DI diesel engine geometry was considered for the analysis. Proper care was taken inidentifying the range of Swirl Ratios. A 3-dimensional CFD code (RECARDO VECTIS, which is capable of solving 3-dimensional unsteady, turbulent flows, sprays and combustion of IC engines was used. In the first step CFD code was validated by comparing the obtained results with the experimental results. In the next step an attempt was made to study the influence of swirl on the spray characteristics and combustion.

  7. Real gas CFD simulations of hydrogen/oxygen supercritical combustion

    Science.gov (United States)

    Pohl, S.; Jarczyk, M.; Pfitzner, M.; Rogg, B.

    2013-03-01

    A comprehensive numerical framework has been established to simulate reacting flows under conditions typically encountered in rocket combustion chambers. The model implemented into the commercial CFD Code ANSYS CFX includes appropriate real gas relations based on the volume-corrected Peng-Robinson (PR) equation of state (EOS) for the flow field and a real gas extension of the laminar flamelet combustion model. The results indicate that the real gas relations have a considerably larger impact on the flow field than on the detailed flame structure. Generally, a realistic flame shape could be achieved for the real gas approach compared to experimental data from the Mascotte test rig V03 operated at ONERA when the differential diffusion processes were only considered within the flame zone.

  8. New approaches for description of nitrogen chemistry in combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Kilpinen, P.; Brink, A.; Norstroem, T. [Aabo Akademi, Turku (Finland)

    1996-12-01

    The aim of the project is to develop novel models for a more accurate description of nitrogen oxide emissions from combustion processes and to increase the understanding of the complex details of homogeneous nitrogen reactions in combustion and gasification. The topics dealt with during 1995 include: (1) effect of Cl on CO oxidation and nitrogen reactions, (2) effect of pressure on NO reduction by SNCR (in co-operation with the project 204), (3) NH{sub 3} conversion to N{sub 2} in gasification gases by selective oxidation (in cooperation with the project 203). In addition, a literature review of the models suggested for the interaction between turbulence and a chemical gas-phase reaction has been made. A commercial CFD code, FLUENT, has also been taken into use. (author)

  9. Numerical modelling of biomass combustion: Solid conversion processes in a fixed bed furnace

    Science.gov (United States)

    Karim, Md. Rezwanul; Naser, Jamal

    2017-06-01

    Increasing demand for energy and rising concerns over global warming has urged the use of renewable energy sources to carry a sustainable development of the world. Bio mass is a renewable energy which has become an important fuel to produce thermal energy or electricity. It is an eco-friendly source of energy as it reduces carbon dioxide emissions. Combustion of solid biomass is a complex phenomenon due to its large varieties and physical structures. Among various systems, fixed bed combustion is the most commonly used technique for thermal conversion of solid biomass. But inadequate knowledge on complex solid conversion processes has limited the development of such combustion system. Numerical modelling of this combustion system has some advantages over experimental analysis. Many important system parameters (e.g. temperature, density, solid fraction) can be estimated inside the entire domain under different working conditions. In this work, a complete numerical model is used for solid conversion processes of biomass combustion in a fixed bed furnace. The combustion system is divided in to solid and gas phase. This model includes several sub models to characterize the solid phase of the combustion with several variables. User defined subroutines are used to introduce solid phase variables in commercial CFD code. Gas phase of combustion is resolved using built-in module of CFD code. Heat transfer model is modified to predict the temperature of solid and gas phases with special radiation heat transfer solution for considering the high absorptivity of the medium. Considering all solid conversion processes the solid phase variables are evaluated. Results obtained are discussed with reference from an experimental burner.

  10. A comprehensive fractal char combustion model☆

    Institute of Scientific and Technical Information of China (English)

    Yuting Liu; Rong He

    2016-01-01

    The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are general y slower than in the air-mode and the effect of the char-CO2 gasification reac-tion becomes obvious only when the temperature is relatively high and the O2 concentration is relatively low.

  11. Li-SF(6) Combustion in Stored Chemical Energy Propulsion Systems

    Science.gov (United States)

    1990-07-01

    Quandt, Jr . Combustion and Fuels Code 2704 Naval Research Laboratory David Taylor Naval Ship Washington, DC 20375 Research and Development Center Annapolis...Oregon State University Department E Corvallis, OR 97331 Oak Ridge, TN 37831 Professor Irvin Glassman Dr. Hugh H. Darsie Department of Mechanical and

  12. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  13. Turbulence-combustion interaction in direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Bencherif Mohamed

    2014-01-01

    Full Text Available The experimental measures of chemical species and turbulence intensity during the closed part of the engine combustion cycle are today unattainable exactly. This paper deals with numerical investigations of an experimental direct injection Diesel engine and a commercial turbocharged heavy duty direct injection one. Simulations are carried out with the kiva3v2 code using the RNG (k-ε model. A reduced mechanism for n-heptane was adopted for predicting auto-ignition and combustion processes. From the calibrated code based on experimental in-cylinder pressures, the study focuses on the turbulence parameters and combustion species evolution in the attempt to improve understanding of turbulence-chemistry interaction during the engine cycle. The turbulent kinetic energy and its dissipation rate are taken as representative parameters of turbulence. The results indicate that chemistry reactions of fuel oxidation during the auto-ignition delay improve the turbulence levels. The peak position of turbulent kinetic energy coincides systematically with the auto-ignition timing. This position seems to be governed by the viscous effects generated by the high pressure level reached at the auto-ignition timing. The hot regime flame decreases rapidly the turbulence intensity successively by the viscous effects during the fast premixed combustion and heat transfer during other periods. It is showed that instable species such as CO are due to deficiency of local mixture preparation during the strong decrease of turbulence energy. Also, an attempt to build an innovative relationship between self-ignition and maximum turbulence level is proposed. This work justifies the suggestion to determine otherwise the self-ignition timing.

  14. UUGM Code Development

    Science.gov (United States)

    1993-07-26

    vitk - stoichiometric coefficient for species i appearing as a product in the kth reaction; ) -- velume fracti3n; a - material density. Subscripts...8217Reaction Propulsion by Intermit- of the Nonsteady Thrust Produced by Intermittent tent Detonative Combustion,’ Ministry of Supply, Pressure Rise in a...Intermittent 5. Hoffmann, N.. "Reaction Propulsion by Intermit- Pressure Rise in a Diverging Channel," ASME FED tent Detonative Combustion," Ministry of

  15. Combustion synthesis method and products

    Science.gov (United States)

    Holt, J.B.; Kelly, M.

    1993-03-30

    Disclosed is a method of producing dense refractory products, comprising: (a) obtaining a quantity of exoergic material in powder form capable of sustaining a combustion synthesis reaction; (b) removing absorbed water vapor therefrom; (c) cold-pressing said material into a formed body; (d) plasma spraying said formed body with a molten exoergic material to form a coat thereon; and (e) igniting said exoergic coated formed body under an inert gas atmosphere and pressure to produce self-sustained combustion synthesis. Also disclosed are products produced by the method.

  16. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  17. Fundamentals of premixed turbulent combustion

    CERN Document Server

    Lipatnikov, Andrei

    2012-01-01

    Lean burning of premixed gases is considered to be a promising combustion technology for future clean and highly efficient gas turbine engines. This book highlights the phenomenology of premixed turbulent flames. The text provides experimental data on the general appearance of premixed turbulent flames, physical mechanisms that could affect flame behavior, and physical and numerical models aimed at predicting the key features of premixed turbulent combustion. The author aims to provide a simple introduction to the field for advanced graduate and postgraduate students. Topics covered include La

  18. Autodesk Combustion 4 fundamentals courseware

    CERN Document Server

    Autodesk,

    2005-01-01

    Whether this is your first experience with Combustion software or you're upgrading to take advantage of the many new features and tools, this guide will serve as your ultimate resource to this all-in-one professional compositing application. Much more than a point-and-click manual, this guide explains the principles behind the software, serving as an overview of the package and associated techniques. Written by certified Autodesk training specialists for motion graphic designers, animators, and visual effects artists, Combustion 4 Fundamentals Courseware provides expert advice for all skill le

  19. Locally Orderless Registration Code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  20. Locally orderless registration code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  1. Contribution to the study of {sup 233}U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/{sup 233}U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code; Contribution a l'etude de la production d'{sup 233}U en combustible MOX-ThPu en reacteur a eau sous pression. Scenarios de transition vers des concepts isogenerateurs Th/{sup 233}U en spectre thermique. Developpement du code MURE d'evolution du combustible

    Energy Technology Data Exchange (ETDEWEB)

    Michel-Sendis, F

    2006-12-15

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  2. Free Energy and Internal Combustion Engine Cycles

    CERN Document Server

    Harris, William D

    2012-01-01

    The performance of one type (Carnot) of Internal Combustion Engine (ICE) cycle is analyzed within the framework of thermodynamic free energies. ICE performance is different from that of an External Combustion Engine (ECE) which is dictated by Carnot's rule.

  3. Scramjet Combustion Stability Behavior Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in combustion stability analysis (UCDS) offers the means to accurately predict the combustion stability of a scramjet. This capability is very...

  4. Scramjet Combustion Stability Behavior Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in combustion stability analysis (UCDS) offers the potential to predict the combustion stability of a scramjet. This capability is very...

  5. Development of a Premixed Combustion Capability for Scramjet Combustion Experiments

    Science.gov (United States)

    Rockwell, Robert D.; Goyne, Christopher P.; Rice, Brian E.; Chelliah, Harsha; McDaniel, James C.; Edwards, Jack R.; Cantu, Luca M. L.; Gallo, Emanuela C. A.; Cutler, Andrew D.; Danehy, Paul M.

    2015-01-01

    Hypersonic air-breathing engines rely on scramjet combustion processes, which involve high speed, compressible, and highly turbulent flows. The combustion environment and the turbulent flames at the heart of these engines are difficult to simulate and study in the laboratory under well controlled conditions. Typically, wind-tunnel testing is performed that more closely approximates engine testing rather than a careful investigation of the underlying physics that drives the combustion process. The experiments described in this paper, along with companion data sets being developed separately, aim to isolate the chemical kinetic effects from the fuel-air mixing process in a dual-mode scramjet combustion environment. A unique fuel injection approach is taken that produces a nearly uniform fuel-air mixture at the entrance to the combustor. This approach relies on the precombustion shock train upstream of the dual-mode scramjet combustor. A stable ethylene flame anchored on a cavity flameholder with a uniformly mixed combustor inflow has been achieved in these experiments allowing numerous companion studies involving coherent anti-Stokes Raman scattering (CARS), particle image velocimetry (PIV), and planar laser induced fluorescence (PLIF) to be performed.

  6. Numerical simulation for explosion wave propagation of combustible mixture gas

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; NING Jian-guo; MA Tian-bao

    2008-01-01

    A two-dimensional multi-material code was indigenously developed to investigate the effects of duct boundary conditions and ignition positions on the propagation law of explosion wave for hydrogen and methane-based combustible mixture gas. In the code, Young's technique was employed to track the interface between the explosion products and air, and combustible function model was adopted to simulate ignition process. The code was employed to study explosion flow field inside and outside the duct and to obtain peak pressures in different boundary conditions and ignition positions. Numerical results suggest that during the propagation in a duct, for point initiation, the curvature of spherical wave front gradually decreases and evolves into plane wave. Due to the multiple reflections on the duct wall, multi-peak values appear on pressure-time curve, and peak pressure strongly relies on the duct boundary conditions and ignition position. When explosive wave reaches the exit of the duct, explosion products expand outward and forms shock wave in air. Multiple rarefaction waves also occur and propagate upstream along the duct to decrease the pressure in the duct. The results are in agreement with one-dimensional isentropic gas flow theory of the explosion products, and indicate that the ignition model and multi-material interface treatment method are feasible.

  7. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers

    NARCIS (Netherlands)

    Sliphorst, M.

    2011-01-01

    Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major issue. High frequency combustion instability (HFCI) is the interaction between combustion and the acoustic field in the combustion c

  8. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers

    NARCIS (Netherlands)

    Sliphorst, M.

    2011-01-01

    Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major issue. High frequency combustion instability (HFCI) is the interaction between combustion and the acoustic field in the combustion c

  9. 结合Forstner与NCC约束的UAV图像配准研究%Integration of Forstner and NCC constraint for UAV image registration

    Institute of Scientific and Technical Information of China (English)

    贺一楠; 耿娟; 秦军; 刘晨; 杨辉

    2015-01-01

    随着无人机( unmanned aerial vehicle,UAV)技术的飞快发展,UAV已成为航空遥感图像获取的重要手段。但与传统的大飞机航空摄影相比,UAV在平台的稳定性方面较差,采集图像时受自身配重、即时飞行环境等外界因素影响,使得最终获得的遥感图像存在复杂的几何变形,导致其图像配准过程存在很大的困难。针对此问题,首先基于UAV的POS数据进行图像重叠区域估算,利用Forstner算子提取图像中的特征点并结合信息熵对图像进行分块处理;然后通过基于旋转的归一化互相关( normalized cross-correlation,NCC)系数寻找相匹配的同名特征点,最终实现UAV图像的配准。实验结果证明该方法切实有效,并且保持了较好的鲁棒性。%With its fast development,the unmanned aerial vehicle (UAV) technology has become an important method for obtaiing the remote sensing image data. Nevertheless, this flexibility, rapid acquisition method for remote sensing image has poor stability in the platform in comparison with the traditional way of large aircraft aerial potography. The acquisition process of UAV image is affected by its counterweight,real-time flight environment and other external factors,and all of these factors lead to a host of difficulties in image registration. In this paper, firstly,the authors used the POS data to estimate the overlapped area of the UAV image, utilized the Forstner operator to extract feature points, and segmented the images based on the entropy information. After that, the matching feature points were found with the rotation model based on normalized cross-correlation( NCC) . Finally, the registration of the UAV images was realized. The experimental results show that the method proposed in this paper is effective and maintains a better robustness.

  10. Combustion Chemistry Diagnostics for Cleaner Processes.

    Science.gov (United States)

    Kohse-Höinghaus, Katharina

    2016-09-12

    Climate change, environmental problems, urban pollution, and the dependence on fossil fuels demand cleaner, renewable energy strategies. However, they also ask for urgent advances in combustion science to reduce emissions. For alternative fuels and new combustion regimes, crucial information about the chemical reactions from fuel to exhaust remains lacking. Understanding such relations between combustion process, fuel, and emissions needs reliable experimental data from a wide range of conditions to provide a firm basis for predictive modeling of practical combustion processes.

  11. Simulation study on combustion of biomass

    Science.gov (United States)

    Zhao, M. L.; Liu, X.; Cheng, J. W.; Liu, Y.; Jin, Y. A.

    2017-01-01

    Biomass combustion is the most common energy conversion technology, offering the advantages of low cost, low risk and high efficiency. In this paper, the transformation and transfer of biomass in the process of combustion are discussed in detail. The process of furnace combustion and gas phase formation was analyzed by numerical simulation. The experimental results not only help to optimize boiler operation and realize the efficient combustion of biomass, but also provide theoretical basis for the improvement of burner technology.

  12. QR Codes 101

    Science.gov (United States)

    Crompton, Helen; LaFrance, Jason; van 't Hooft, Mark

    2012-01-01

    A QR (quick-response) code is a two-dimensional scannable code, similar in function to a traditional bar code that one might find on a product at the supermarket. The main difference between the two is that, while a traditional bar code can hold a maximum of only 20 digits, a QR code can hold up to 7,089 characters, so it can contain much more…

  13. Constructing quantum codes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Quantum error correcting codes are indispensable for quantum information processing and quantum computation.In 1995 and 1996,Shor and Steane gave first several examples of quantum codes from classical error correcting codes.The construction of efficient quantum codes is now an active multi-discipline research field.In this paper we review the known several constructions of quantum codes and present some examples.

  14. Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode

    Science.gov (United States)

    Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

    2008-10-07

    This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

  15. Combustor nozzle for a fuel-flexible combustion system

    Science.gov (United States)

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  16. 30 CFR 56.4104 - Combustible waste.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Combustible waste. 56.4104 Section 56.4104... Control Prohibitions/precautions/housekeeping § 56.4104 Combustible waste. (a) Waste materials, including... properly, waste or rags containing flammable or combustible liquids that could create a fire hazard shall...

  17. Straw combustion on slow-moving grates

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2005-01-01

    Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ‘‘walking...

  18. Combustion Characteristics in a Non-Premixed Cool-Flame Regime of n-Heptane in Microgravity

    Science.gov (United States)

    Takahashi, Fumiaki; Katta, Viswanath R.; Hicks, Michael C.

    2015-01-01

    A series of distinct phenomena have recently been observed in single-fuel-droplet combustion tests performed on the International Space Station (ISS). This study attempts to simulate the observed flame behavior numerically using a gaseous n-heptane fuel source in zero gravity and a time-dependent axisymmetric (2D) code, which includes a detailed reaction mechanism (127 species and 1130 reactions), diffusive transport, and a radiation model (for CH4, CO, CO2, H2O, and soot). The calculated combustion characteristics depend strongly on the air velocity around the fuel source. In a near-quiescent air environment (combustion experiments.

  19. The Crystallization Behaviors and Thermal Properties of PVA/NCC Composite Films%聚乙烯醇/纳米纤维素晶体复合膜热学性能

    Institute of Scientific and Technical Information of China (English)

    唐丽荣; 黄彪; 戴达松; 欧文; 李玉华; 陈学榕

    2011-01-01

    以微晶纤维素(MCC)为原料,通过硫酸水解得到纳米纤维素晶体(NCC),再将纳米纤维素晶体与聚乙烯醇复合共混制备聚乙烯醇/纳米纤维素晶体复合膜,研究复合膜的热学性能,同时采用场发射透射电镜(FETEM)、场发射扫描电镜( FE-SEM)、原子力显微镜(AFM)、热重分析(TG)、差示扫描量热仪(DSC)等仪器对纳米纤维素晶体及其复合膜进行表征与分析.结果表明:所制得的纳米纤维素晶体直径约2~24 nm,50~450 nm长,呈棒状;由FE-SEM图可观察到纳米纤维素晶体与聚乙烯醇具有良好的界面相互作用,但在较大添加量7%时,NCC出现部分团聚,与基体的相容性下降;由TG和DSC分析说明NCC与PVA基体可较好相容,形成了热稳定性较好的复合膜,但当NCC添加量较大时,由于团聚使复合膜热稳定性下降.%Nanocellulose crystal( NCC) was prepared from microcrystalline cellulose ( MCC ) by sulfuric acid treatment, and composite films were prepared from polyvinyl alcohol(PVA) as the matrix and NCC as the filler. Their morphology, size and thermal properties were characterized by field emission transmission electron microscopy ( FETEM) , atomic force microscopy ( AFM ) , field emission gun environment scanning electron microscopes ( FEGE-SEM ) , thermogravimetric analysis(TG)and differential scanning calorimetry ( DSC ). The results indicated that the diameter of NCC was about 2 -24 nm, with the length 50 -450 nm. From FE-SEM images, it could be observed that PVA /NCC composite films were created by casting from a water suspension to produce a homogeneous dispersion of NCC in the polymer matrix. But it showed some agglomeration when the filler loading reached to 7% , and the interaction between NCC and PVA decreased. TG and DSC analysis showed excellent interaction between NCC and PVA. The composite films filled with nanocellulose crystal exhibited improved thermal properties as compared to the neat PVA film. On the

  20. Sulfur Chemistry in Combustion II

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Kiil, Søren

    2000-01-01

    Several options are available to control the emission of SO2 from combustion processes. One possibility is to use a cleaner technology, i.e. fuel switching from oil and coal to natural gas or biomass, or to desulphurize coal and oil. Another possibility is to change to a different technology for ...

  1. Leaching from biomass combustion ash

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2014-01-01

    The use of biomass combustion ashes for fertilizing and liming purposes has been widely addressed in scientific literature. Nevertheless, the content of potentially toxic compounds raises concerns for a possible contamination of the soil. During this study five ash samples generated at four...

  2. Turbo Codes Extended with Outer BCH Code

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    1996-01-01

    The "error floor" observed in several simulations with the turbo codes is verified by calculation of an upper bound to the bit error rate for the ensemble of all interleavers. Also an easy way to calculate the weight enumerator used in this bound is presented. An extended coding scheme is proposed...

  3. Simulation of hydrogen combustion during spray operation with COCOSYS

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Tobias; Koch, Marco K. [Ruhr-Univ. Bochum (Germany). Reactor Simulation and Safety Group

    2017-01-15

    The OECD/NEA THAI-2 test HD-33 is simulated with the Containment Code System COCOSYS. The test investigates hydrogen deflagration during spray system operation. Two calculations with different input parameters are performed to show the general capabilities of the deflagration model FRONT. Nevertheless, the experimental flame front propagation is not simulated sufficiently by the ignition of the zones, because of a missing interface between the used spray and combustion model as well as a neglect of spray induced turbulences. Therefore it might be thought about a more mechanistic approach.

  4. Environmental optimisation of waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Robert [AaF Energikonsult, Stockholm (Sweden); Berge, Niclas; Stroemberg, Birgitta [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-12-01

    The regulations concerning waste combustion evolve through R and D and a strive to get better and common regulations for the European countries. This study discusses if these rules of today concerning oxygen concentration, minimum temperature and residence time in the furnace and the use of stand-by burners are needed, are possible to monitor, are the optimum from an environmental point of view or could be improved. No evidence from well controlled laboratory experiments validate that 850 deg C in 6 % oxygen content in general is the best lower limit. A lower excess air level increase the temperature, which has a significant effect on the destruction of hydrocarbons, favourably increases the residence time, increases the thermal efficiency and the efficiency of the precipitators. Low oxygen content is also necessary to achieve low NO{sub x}-emissions. The conclusion is that the demands on the accuracy of the measurement devices and methods are too high, if they are to be used inside the furnace to control the combustion process. The big problem is however to find representative locations to measure temperature, oxygen content and residence time in the furnace. Another major problem is that the monitoring of the operation conditions today do not secure a good combustion. It can lead to a false security. The reason is that it is very hard to find boilers without stratifications. These stratifications (stream lines) has each a different history of residence time, mixing time, oxygen and combustible gas levels and temperature, when they reach the convection area. The combustion result is the sum of all these different histories. The hydrocarbons emission is in general not produced at a steady level. Small clouds of unburnt hydrocarbons travels along the stream lines showing up as peaks on a THC measurement device. High amplitude peaks has a tendency to contain higher ratio of heavy hydrocarbons than lower peaks. The good correlation between some easily detected

  5. Benchmarking Of Improved DPAC Transient Deflagration Analysis Code

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, James E.; Hensel, Steve J.

    2013-03-21

    The transient deflagration code DPAC (Deflagration Pressure Analysis Code) has been upgraded for use in modeling hydrogen deflagration transients. The upgraded code is benchmarked using data from vented hydrogen deflagration tests conducted at the HYDRO-SC Test Facility at the University of Pisa. DPAC originally was written to calculate peak deflagration pressures for deflagrations in radioactive waste storage tanks and process facilities at the Savannah River Site. Upgrades include the addition of a laminar flame speed correlation for hydrogen deflagrations and a mechanistic model for turbulent flame propagation, incorporation of inertial effects during venting, and inclusion of the effect of water vapor condensation on vessel walls. In addition, DPAC has been coupled with CEA, a NASA combustion chemistry code. The deflagration tests are modeled as end-to-end deflagrations. The improved DPAC code successfully predicts both the peak pressures during the deflagration tests and the times at which the pressure peaks.

  6. Fluidized-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Kudjoi, A.; Heinolainen, A.; Hippinen, I.; Lu, Y. [Helsinki University of Technology, Espoo (Finland). Lab. of Energy Economics and Power Plant Engineering

    1998-12-31

    Hybrid combined cycle processes have been presented as possibilities for power generation in the future. In the processes based on partial gasification of coal, the solid materials removed from a gasifier (i.e. fly ash and bed char) contain unburned fuel, which is burned either in an atmospheric or a pressurised fluidised-bed. Pressurised fluidised-bed (PFB) combustion of gasification residues were studied experimentally by Helsinki University of Technology. The gasification residues, i.e. cyclone fines and bed chars, came from pilot scale PFB gasification tests of bituminous coals. The combustion efficiency was high in cyclone fines combustion. The calcium sulphide oxidised effectively to calcium sulphate in the combustion of cyclone fines. In bed char combustion the residual sulphide contents in solids after combustion were still relatively high. In general, sulphur dioxide emissions in residue combustion were low. The recarbonation of calcium oxide was observed in bed char combustion. Fuel-N conversion to NO{sub x} during bed char combustion and in most of the test runs with cyclone fines was higher than in bituminous coal combustion. In bed char combustion the conversion was significantly higher than in cyclone fines combustion. NO{sub x} emissions increased with increasing excess air for both residues, as was expected. In bed char combustion the highest NO{sub x} emissions were measured at higher pressure. Calculated mass reactivity values of equal particle size of all bed chars studied had similar trends with burnout. The biggest particles had the lowest reactivity values throughout the combustion, while reactivity for finer particles was at considerably higher level and sharply increases with burnout. In the constant combustion conditions used in the tests, no significant differences were observed in rate-controlling mechanisms for bed char fractions studied. 25 refs., 13 figs., 15 tab.

  7. Hybrid Noncoherent Network Coding

    CERN Document Server

    Skachek, Vitaly; Nedic, Angelia

    2011-01-01

    We describe a novel extension of subspace codes for noncoherent networks, suitable for use when the network is viewed as a communication system that introduces both dimension and symbol errors. We show that when symbol erasures occur in a significantly large number of different basis vectors transmitted through the network and when the min-cut of the networks is much smaller then the length of the transmitted codewords, the new family of codes outperforms their subspace code counterparts. For the proposed coding scheme, termed hybrid network coding, we derive two upper bounds on the size of the codes. These bounds represent a variation of the Singleton and of the sphere-packing bound. We show that a simple concatenated scheme that represents a combination of subspace codes and Reed-Solomon codes is asymptotically optimal with respect to the Singleton bound. Finally, we describe two efficient decoding algorithms for concatenated subspace codes that in certain cases have smaller complexity than subspace decoder...

  8. Combustive management of oil spills

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Extensive experiments with in situ incineration were performed on a desert site at the University of Arizona with very striking results. The largest incinerator, 6 feet in diameter with a 30 foot chimney, developed combustion temperatures of 3000, F, and attendant soot production approximately 1000 times less than that produced by conventional in situ burning. This soot production, in fact, is approximately 30 times less than current allowable EPA standards for incinerators and internal combustion engines. Furthermore, as a consequence of the high temperature combustion, the bum rate was established at a very high 3400 gallons per hour for this particular 6 foot diameter structure. The rudimentary design studies we have carried out relative to a seagoing 8 foot diameter incinerator have predicted that a continuous burn rate of 7000 gallons per hour is realistic. This structure was taken as a basis for operational design because it is compatible with C130 flyability, and will be inexpensive enough ($120,000 per copy) to be stored at those seaside depots throughout the US coast line in which the requisite ancillary equipments (booms, service tugs, etc.) are already deployed. The LOX experiments verified our expectations with respect to combustion of debris and various highly weathered or emulsified oils. We have concluded, however, that the use of liquid oxygen in actual beach clean up is not promising because the very high temperatures associated with this combustion are almost certain to produce environmentally deleterious effects on the beach surface and its immediately sublying structures. However, the use of liquid oxygen augmentation for shore based and flyable incinerators may still play an important role in handing the problem of accumulated debris.

  9. Numerical Analysis of Autoignition and Combustion of n-Butane and Air Mixture in Homogeneous-Charge Compression-Ignition Engine Using Elementary Reactions

    Science.gov (United States)

    Yamasaki, Yudai; Iida, Norimasa

    The present study focuses on clarifying the combustion mechanism of the homogeneous-charge compression-ignition (HCCI) engine in order to control ignition and combustion as well as to reduce HC and CO emissions and to maintain high combustion efficiency by calculating the chemical kinetics of elementary reactions. For the calculations, n-butane was selected as fuel since it is a fuel with the smallest carbon number in the alkane family that shows two-stage autoignition (heat release with low-temperature reaction (LTR) and with high-temperature reaction (HTR)) similarly to higher hydrocarbons such as gasoline. The CHEMKIN code was used for the calculations assuming zero dimensions in the combustion chamber and adiabatic change. The results reveal the heat release mechanism of the LTR and HTR, the control factor of ignition timing and combustion speed, and the condition need to reduce HC and CO emissions and to maintain high combustion efficiency.

  10. Box-Behnken design for extraction optimization of crude polysaccharides from Tunisian Phormidium versicolor cyanobacteria (NCC 466): Partial characterization, in vitro antioxidant and antimicrobial activities.

    Science.gov (United States)

    Belhaj, Dalel; Frikha, Donyez; Athmouni, Khaled; Jerbi, Bouthaina; Ahmed, Mohammad Boshir; Bouallagui, Zouhaier; Kallel, Monem; Maalej, Sami; Zhou, John; Ayadi, Habib

    2017-06-09

    In this study, response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to optimize the aqueous extraction of crude polysaccharides from Tunisian cyanobacteria Phormidium versicolor (NCC 466). The optimal extraction conditions with an extraction yield of 21.56±0.92% were as follows: extraction temperature at 81.05°C, extraction time of 3.99h, and water to raw material ratio of 21.52mLg(-1). Crude Phormidium versicolor polysaccharides (CPv-PS) are found to be a hetero-sulfated-anionic polysaccharides that contained carbohydrate (79.37±1.58%), protein (0.45±0.11%), uronic acids (4.37±0.19%) and sulfate (6.83±0.28%). The carbohydrate fraction was composed of arabinose, xylose, ribose, rhamnose, N-acetyl glucosamine, galactose, glucose, mannose, glucuronic acid and saccharose with corresponding mole percentages of 2.41, 14.58, 2.18, 6.23, 7.04, 28.21, 26.04, 3.02, 0.86 and 5.07, respectively. Evaluation of the antioxidant activity in vitro suggested that CPv-PS strongly scavenged radicals, prevented bleaching of β-carotene and reduced activity. Furthermore, the CPv-PS exhibited effective antimicrobial properties. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  11. Gene expression and morphological localization of NHE3, NCC and NKCC1a in branchial mitochondria-rich cells of Mozambique tilapia (Oreochromis mossambicus) acclimated to a wide range of salinities.

    Science.gov (United States)

    Inokuchi, Mayu; Hiroi, Junya; Watanabe, Soichi; Lee, Kyung Mi; Kaneko, Toyoji

    2008-10-01

    We explored molecular and morphological alteration in gill mitochondria-rich (MR) cells of Mozambique tilapia, Oreochromis mossambicus, acclimated to deionized freshwater (DFW), freshwater (FW), 1/3-diluted seawater (1/3 SW) and seawater (SW). Scanning electron microscopic observations revealed that the apical membrane of MR cells appeared as a flat or slightly projecting disk in DFW and FW, being larger in DFW than in FW. In contrast, the apical membrane typically formed a pit structure in 1/3 SW and SW. The mRNA expression levels of Na(+)/H(+) exchanger-3 (NHE3) and Na(+)/Cl(-) cotransporter (NCC) in the gills were increased with decreasing environmental salinity, whereas Na(+)/K(+)/2Cl(-) cotransporter-1a (NKCC1a) expression was upregulated by increasing salinity. Immunofluorescence staining showed that the MR cell population of DFW- and FW-acclimated tilapia consisted mostly of MR cells with apical NHE3 and those with apical-NCC; MR cells with basolateral NKCC1a dominated in SW-acclimated tilapia. These results indicated that apical-NHE3 and apical-NCC MR cells were ion-absorbing cells, and that basolateral-NKCC1a MR cells were ion-secreting cells. In fish acclimated to 1/3 SW, both ion-absorbing and secreting cells existed in the gills, suggesting that fish in near-isotonic water were equipped with mechanisms of both hyper- and hypoosmoregulation to prepare for environmental salinity changes.

  12. Numerical study of premixed HCCI engine combustion and its sensitivity to computational mesh and model uncertainties

    Science.gov (United States)

    Kong, Song-Charng; Reitz, Rolf D.

    2003-06-01

    This study used a numerical model to investigate the combustion process in a premixed iso-octane homogeneous charge compression ignition (HCCI) engine. The engine was a supercharged Cummins C engine operated under HCCI conditions. The CHEMKIN code was implemented into an updated KIVA-3V code so that the combustion could be modelled using detailed chemistry in the context of engine CFD simulations. The model was able to accurately simulate the ignition timing and combustion phasing for various engine conditions. The unburned hydrocarbon emissions were also well predicted while the carbon monoxide emissions were under predicted. Model results showed that the majority of unburned hydrocarbon is located in the piston-ring crevice region and the carbon monoxide resides in the vicinity of the cylinder walls. A sensitivity study of the computational grid resolution indicated that the combustion predictions were relatively insensitive to the grid density. However, the piston-ring crevice region needed to be simulated with high resolution to obtain accurate emissions predictions. The model results also indicated that HCCI combustion and emissions are very sensitive to the initial mixture temperature. The computations also show that the carbon monoxide emissions prediction can be significantly improved by modifying a key oxidation reaction rate constant.

  13. Heat transfer in rocket engine combustion chambers and regeneratively cooled nozzles

    Science.gov (United States)

    1993-01-01

    A conjugate heat transfer computational fluid dynamics (CFD) model to describe regenerative cooling in the main combustion chamber and nozzle and in the injector faceplate region for a launch vehicle class liquid rocket engine was developed. An injector model for sprays which treats the fluid as a variable density, single-phase media was formulated, incorporated into a version of the FDNS code, and used to simulate the injector flow typical of that in the Space Shuttle Main Engine (SSME). Various chamber related heat transfer analyses were made to verify the predictive capability of the conjugate heat transfer analysis provided by the FDNS code. The density based version of the FDNS code with the real fluid property models developed was successful in predicting the streamtube combustion of individual injector elements.

  14. Report on Investigation of Alcohol Combustion Associated Wear in Spark Ignition Engines, Mechanisms and Lubricant Effects.

    Science.gov (United States)

    1984-12-01

    Combustion Associated Wear in Spark-Ignition Enzines 12. PERSONAL AUTHORISI INaegeli, David N. and Owens, Edwin C. 131. TYPE OF REPORT 13b. TIME COVERED 114...READINESS CMD ATTN: STEYP-MLS-M (MR DOEBBLER) I -. ATTN: AMSAR-LEM 1 YUMA AZ 85364 ROCK ISLAND ARSENAL IL 61299 PROJ MGR, BRADELY FIGHTING - CDR...CHIEF OF NAVAL RESEARCH CDR ATTN: CODE 473 1 DAVID TAYLOR NAVAL SHIP R&D CTR ARLINGTON VA 22217 ATTN: CODE 2830 (MR G BOSMAJIAN) 1 CODE 2705.1 (MR

  15. Secondary combustion device for woodburning stove

    Energy Technology Data Exchange (ETDEWEB)

    Craver, R.D.

    1989-08-08

    This patent describes in a wood burning stove including an exhaust flue opening, a combustion chamber for primary combustion having an access door, a support for wood to be burned and a primary air inlet means for supplying air to support primary combustion of the wood to produce flue gases containing combustible particulate material, plenum means for directing the flue gases in a direction from the combustion chamber to the flue opening in a preselected path, and secondary combustion means for burning the particulate material in the flue gases before flue gases through the exhaust flue opening. The improvement comprising: the combustion chamber having a flue gas exit opening extending laterally across the top of the combustion chamber and communicating the combustion chamber with the plenum means, an elongated manifold extending laterally across and above the combustion chamber substantially coextensively with the flue gas exit opening, a number of air opening spaced longitudinally along the manifold and facing opposite the direction of the flue gases closely adjacent the flue gas exit opening, and an air inlet means for supplying ambient, secondary combustion air to the manifold for counterflow thereof from the openings into the path of the flue gases in a plurality of distinct jets.

  16. Measurement and simulation of swirling coal combustion

    Institute of Scientific and Technical Information of China (English)

    Liyuan Hu; Lixing Zhou; Yonghao Luo; Caisong Xu

    2013-01-01

    Particle image velocimetry (PIV),thermocouples and flue gas analyzer are used to study swirling coal combustion and NO formation under different secondary-air ratios.Eulerian-Lagrangian large-eddy simulation (LES) using the Smagorinsky-Lilly sub-grid scale stress model,presumed-PDF fast chemistry and eddy-break-up (EBU) gas combustion models,particle devolatilization and particle combustion models,are simultaneously used to simulate swirling coal combustion.Statistical LES results are validated by measurement results.Instantaneous LES results show that the coherent structures for swirling coal combustion are stronger than those for swirling gas combustion.Particles are shown to concentrate along the periphery of the coherent structures.Combustion flame is located in the high vorticity and high particle concentration zones.Measurement shows that secondary-air ratios have little effect on final NO formation at the exit of the combustor.

  17. Combustion diagnostic for active engine feedback control

    Science.gov (United States)

    Green, Jr., Johney Boyd; Daw, Charles Stuart; Wagner, Robert Milton

    2007-10-02

    This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

  18. Combustion research in the Internal Fluid Mechanics Division

    Science.gov (United States)

    Mularz, Edward J.

    1986-01-01

    The goal of this research is to bring computational fluid dynamics to a state of practical application for the aircraft engine industry. The approach is to have a strongly integrated computational and experimental program for all the disciplines associated with the gas turbine and other aeropropulsion systems by advancing the understanding of flow physics, heat transfer, and combustion processes. The computational and experimental research is integrated in the following way: the experiments that are performed provide an empirical data set so that physical models can be formulated to describe the processes that are occurring - for example, turbulence or chemical reaction. These experiments also form a data base for those who are doing code development by providing experimental data against which the codes can be verified and assesed. Models are generated as closure to some of the numerical codes, and they also provide physical insight for experiments. At the same time, codes which solve the complete Navier-Stokes equations can be used as a kind of numerical experiment from which far more extensive data can be obtained than ever could be obtained experimentally. This could provide physical insight into the complex processes that are taking place. These codes are also exercised against experimental data to assess the accuracy and applicability of models.

  19. Network coding for computing: Linear codes

    CERN Document Server

    Appuswamy, Rathinakumar; Karamchandani, Nikhil; Zeger, Kenneth

    2011-01-01

    In network coding it is known that linear codes are sufficient to achieve the coding capacity in multicast networks and that they are not sufficient in general to achieve the coding capacity in non-multicast networks. In network computing, Rai, Dey, and Shenvi have recently shown that linear codes are not sufficient in general for solvability of multi-receiver networks with scalar linear target functions. We study single receiver networks where the receiver node demands a target function of the source messages. We show that linear codes may provide a computing capacity advantage over routing only when the receiver demands a `linearly-reducible' target function. % Many known target functions including the arithmetic sum, minimum, and maximum are not linearly-reducible. Thus, the use of non-linear codes is essential in order to obtain a computing capacity advantage over routing if the receiver demands a target function that is not linearly-reducible. We also show that if a target function is linearly-reducible,...

  20. Combustion and Performance Analyses of Coaxial Element Injectors with Liquid Oxygen/Liquid Methane Propellants

    Science.gov (United States)

    Hulka, J. R.; Jones, G. W.

    2010-01-01

    Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for in-space vehicles. This propellant combination has not been previously used in a flight-qualified engine system, so limited test data and analysis results are available at this stage of early development. NASA has funded several hardware-oriented activities with oxygen and methane propellants over the past several years with the Propulsion and Cryogenic Advanced Development (PCAD) project, under the Exploration Technology Development Program. As part of this effort, the NASA Marshall Space Flight Center has conducted combustion, performance, and combustion stability analyses of several of the configurations. This paper summarizes the analyses of combustion and performance as a follow-up to a paper published in the 2008 JANNAF/LPS meeting. Combustion stability analyses are presented in a separate paper. The current paper includes test and analysis results of coaxial element injectors using liquid oxygen and liquid methane or gaseous methane propellants. Several thrust chamber configurations have been modeled, including thrust chambers with multi-element swirl coax element injectors tested at the NASA MSFC, and a uni-element chamber with shear and swirl coax injectors tested at The Pennsylvania State University. Configurations were modeled with two one-dimensional liquid rocket combustion analysis codes, the Rocket Combustor Interaction Design and Analysis (ROCCID), and the Coaxial Injector Combustion Model (CICM). Significant effort was applied to show how these codes can be used to model combustion and performance with oxygen/methane propellants a priori, and what anchoring or calibrating features need to be applied or developed in the future. This paper describes the test hardware configurations, presents the results of all the analyses, and compares the results from the two analytical methods

  1. Distributed Low Temperature Combustion: Fundamental Understanding of Combustion Regime Transitions

    Science.gov (United States)

    2016-09-07

    Excellent optical access for laser- based diagnostic measurements ; (ii) Accurate experimental control of boundary conditions; (iii) Aerodynamic flame...potential to extend methods based on bimodal approximations, such as the BML [21] framework , by permitting inter- mediate fluid states, which is of...identify the impact of the major chemical pathways on combustion mode transitions. The conceptual multifluid approach of Spalding can be used to avoid

  2. 77 FR 37361 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Science.gov (United States)

    2012-06-21

    ... Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion... Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines.'' The EPA... Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines...

  3. Three-dimensional modeling of diesel engine intake flow, combustion and emissions

    Science.gov (United States)

    Reitz, R. D.; Rutland, C. J.

    1992-01-01

    A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation, and the intake flow process. Improved and/or new submodels which were completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and finally, the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To date, comparisons with measured engine cylinder pressure and heat flux data were made for homogeneous charge, spark-ignited and compression-ignited engines. The model results are in good agreement with the experiments.

  4. A study of three-dimensional LES of turbulent combustion with radiative heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R. Goncalves dos, E-mail: roger7@fem.unicamp.br [Universidade de Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Mecania; Ducruix, S.; Gicquel, O.; Veynate, D. [Laboratoire EM2C, CNRS and Ecole Centrale Paris, 92295, Châtenay-Malabry (France)

    2016-01-15

    Combustion, one of the main forms of energy production nowadays, is a complex phenomenon in which turbulent flow, chemical reactions, different phases and heat transfer phenomena can interact. A better understanding of these interactions is essential to improve existing combustion systems and develop new ones. The aim of this work was to study the interaction of turbulent combustion with thermal radiation with the aid of three-dimensional numerical simulation. Using the CORBA computational tool, a code for Large Eddy Simulation (LES) of combustion was coupled with a radiative heat transfer code. This technique allows information to be exchanged between the two codes without major changes in their structure, so that advantage can be taken of the different characteristic time of each phenomenon in a high-performance parallel-computing environment. This study is the continuation of an earlier two-dimensional study. The results show a change in the temperature and species fields as well as in the flame dynamics when thermal radiation is taken into account. (author)

  5. Characterisation of fuels for advanced pressurised combustion

    Energy Technology Data Exchange (ETDEWEB)

    Zevenhoven, R.; Hupa, M.; Backman, P.; Forssen, M.; Karlsson, M.; Kullberg, M.; Sorvari, V.; Uusikartano, T. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group; Nurk, M. [Tallinskij Politekhnicheskij Inst., Tallinn (Estonia)

    1997-10-01

    The objective of the research was to determine a set of fuel characteristics which quantify the behaviour of a fuel in a typical pressurised combustor or gasifier environment, especially in hybrid processes such as second generation PFBC. One specific aspect was to cover a wide range of fuels, including several coal types and several grades of peat and biomasses: 7 types of coal, 2 types of peat, 2 types of wood, 2 types of black liquor, Estonian oil shale and Venezuelan Orimulsion were studied. The laboratory facilities used are a pressurised thermogravimetric reactor (PTGR), a pressurised grid heater (PGH) and an atmospheric entrained flow quartz tube reactor, with gas analysis, which can be operated as a fixed bed reactor. A major part of the work was related to fuel devolatilisation in the PGH and sequential devolatilisation and char gasification (with carbon dioxide or steam) in the PTGR. The final part of that work is reported here, with the combustion of Estonian oil shale at AFBC or PFBC conditions as additional subject. Devolatilisation of the fuels at atmospheric pressure in nitrogen while monitoring gaseous exhausts, followed by ultimate analysis of the chars has been reported earlier. Here, results on the analysis of the reduction of NO (with and without CO) on chars at atmospheric pressure in a fixed bed reactor are reported. Finally, a comparison is given between experimental results and direct numerical simulation with several computer codes, i.e. PyroSim, developed at TU Graz, Austria, and the codes Partikkeli, Pisara and Cogas, which were provided by VTT Energy, Jyvaeskylae

  6. Combustion Model FOr Staged Circulating Fluidized Bed BOiler

    Institute of Scientific and Technical Information of China (English)

    FandJianhua; LuQinggang; 等

    1997-01-01

    A mathematical model for atmospheric staged circulating fluidized bed combustion,which takes fluid dynamics,combustion,heat transfer,pollutants formation and retention,into account was developed in the institute of Engineering Thermophysics(IET)recently.The model of gas solid flow at the bottom of the combustor was treated by the two-phase theory of fluidized bed and in the upper region as a core-annulus flow structure.The chemical species CO,CO2,H2,H2O,CH4,O2 and N2 were considered in the reaction process.The mathematical model consisted of sub-modeles of fluid namics,coal heterogeneous and gas homogeneous chemical reactions.heat transfer,particle fragmentation and attrition,mass and energy balance tec.The developed code was applied to simulate an operating staged circulating fluidized bed combustion boiler of early design and the results were in good agreement with the operating data.The main submodels and simulation results are given in this paoper.

  7. Practices in Code Discoverability

    CERN Document Server

    Teuben, Peter; Nemiroff, Robert J; Shamir, Lior

    2012-01-01

    Much of scientific progress now hinges on the reliability, falsifiability and reproducibility of computer source codes. Astrophysics in particular is a discipline that today leads other sciences in making useful scientific components freely available online, including data, abstracts, preprints, and fully published papers, yet even today many astrophysics source codes remain hidden from public view. We review the importance and history of source codes in astrophysics and previous efforts to develop ways in which information about astrophysics codes can be shared. We also discuss why some scientist coders resist sharing or publishing their codes, the reasons for and importance of overcoming this resistance, and alert the community to a reworking of one of the first attempts for sharing codes, the Astrophysics Source Code Library (ASCL). We discuss the implementation of the ASCL in an accompanying poster paper. We suggest that code could be given a similar level of referencing as data gets in repositories such ...

  8. Coding for optical channels

    CERN Document Server

    Djordjevic, Ivan; Vasic, Bane

    2010-01-01

    This unique book provides a coherent and comprehensive introduction to the fundamentals of optical communications, signal processing and coding for optical channels. It is the first to integrate the fundamentals of coding theory and optical communication.

  9. Enhancing QR Code Security

    OpenAIRE

    Zhang, Linfan; Zheng, Shuang

    2015-01-01

    Quick Response code opens possibility to convey data in a unique way yet insufficient prevention and protection might lead into QR code being exploited on behalf of attackers. This thesis starts by presenting a general introduction of background and stating two problems regarding QR code security, which followed by a comprehensive research on both QR code itself and related issues. From the research a solution taking advantages of cloud and cryptography together with an implementation come af...

  10. TWO-DIMENSIONAL AXISYMMETRIC MODELING OF COMBUSTION IN AN IRON ORE SINTERING BED

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Davazdah Emami, Mohsen; Panjehpour, Masoud;

    2013-01-01

    A twodimensional model, based on conservation of mass, momentum and energy equations, is represented in this paper in which the coke combustion process, for iron ore sintering in a packed bed, is simulated numerically. The aforementioned packed bed consists of iron ore, coke, limestone and moisture...... of species are solved numerically by using a computational fluid dynamics code in a discrete solving domain. Modeling of iron ore sintering has complex and various features like coke combustion, complicated physical changes of solid phase particles and different modes of heat transfer, for example convection...

  11. Refactoring test code

    NARCIS (Netherlands)

    A. van Deursen (Arie); L.M.F. Moonen (Leon); A. van den Bergh; G. Kok

    2001-01-01

    textabstractTwo key aspects of extreme programming (XP) are unit testing and merciless refactoring. Given the fact that the ideal test code / production code ratio approaches 1:1, it is not surprising that unit tests are being refactored. We found that refactoring test code is different from

  12. Informal Control code logic

    CERN Document Server

    Bergstra, Jan A

    2010-01-01

    General definitions as well as rules of reasoning regarding control code production, distribution, deployment, and usage are described. The role of testing, trust, confidence and risk analysis is considered. A rationale for control code testing is sought and found for the case of safety critical embedded control code.

  13. Gauge color codes

    DEFF Research Database (Denmark)

    Bombin Palomo, Hector

    2015-01-01

    Color codes are topological stabilizer codes with unusual transversality properties. Here I show that their group of transversal gates is optimal and only depends on the spatial dimension, not the local geometry. I also introduce a generalized, subsystem version of color codes. In 3D they allow...

  14. Refactoring test code

    NARCIS (Netherlands)

    Deursen, A. van; Moonen, L.M.F.; Bergh, A. van den; Kok, G.

    2001-01-01

    Two key aspects of extreme programming (XP) are unit testing and merciless refactoring. Given the fact that the ideal test code / production code ratio approaches 1:1, it is not surprising that unit tests are being refactored. We found that refactoring test code is different from refactoring product

  15. ARC Code TI: CODE Software Framework

    Data.gov (United States)

    National Aeronautics and Space Administration — CODE is a software framework for control and observation in distributed environments. The basic functionality of the framework allows a user to observe a distributed...

  16. ARC Code TI: ROC Curve Code Augmentation

    Data.gov (United States)

    National Aeronautics and Space Administration — ROC (Receiver Operating Characteristic) curve Code Augmentation was written by Rodney Martin and John Stutz at NASA Ames Research Center and is a modification of ROC...

  17. Fountain Codes: LT And Raptor Codes Implementation

    Directory of Open Access Journals (Sweden)

    Ali Bazzi, Hiba Harb

    2017-01-01

    Full Text Available Digital fountain codes are a new class of random error correcting codes designed for efficient and reliable data delivery over erasure channels such as internet. These codes were developed to provide robustness against erasures in a way that resembles a fountain of water. A digital fountain is rateless in a way that sender can send limitless number of encoded packets. The receiver doesn’t care which packets are received or lost as long as the receiver gets enough packets to recover original data. In this paper, the design of the fountain codes is explored with its implementation of the encoding and decoding algorithm so that the performance in terms of encoding/decoding symbols, reception overhead, data length, and failure probability is studied.

  18. Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, William de

    2010-07-31

    The project which extended from November 2005 to May of 2010 demonstrated the application of Low Temperature Combustion (LTC) with engine out NOx levels of 0.2 g/bhp-hr throughout the program target load of 12.6bar BMEP. The project showed that the range of loads could be extended to 16.5bar BMEP, therefore matching the reference lug line of the base 2007 MY Navistar 6.4L V8 engine. Results showed that the application of LTC provided a dramatic improvement over engine out emissions when compared to the base engine. Furthermore LTC improved thermal efficiency by over 5% from the base production engine when using the steady state 13 mode composite test as a benchmark. The key enablers included improvements in the air, fuel injection, and cooling systems made in Phases I and II. The outcome was the product of a careful integration of each component under an intelligent control system. The engine hardware provided the conditions to support LTC and the controller provided the necessary robustness for a stable combustion. Phase III provided a detailed account on the injection strategy used to meet the high load requirements. During this phase, the control strategy was implemented in a production automotive grade ECU to perform cycle-by-cycle combustion feedback on each of the engine cylinders. The control interacted on a cycle base with the injection system and with the Turbo-EGR systems according to their respective time constants. The result was a unique system that could, first, help optimize the combustion system and maintain high efficiency, and secondly, extend the steady state results to the transient mode of operation. The engine was upgraded in Phase IV with a Variable Valve Actuation system and a hybrid EGR loop. The impact of the more versatile EGR loop did not provide significant advantages, however the application of VVA proved to be an enabler to further extend the operation of LTC and gain considerable benefits in fuel economy and soot reduction. Finally

  19. Oxy-coal Combustion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J. [Univ. of Utah, Salt Lake City, UT (United States); Eddings, E. [Univ. of Utah, Salt Lake City, UT (United States); Lighty, J. [Univ. of Utah, Salt Lake City, UT (United States); Ring, T. [Univ. of Utah, Salt Lake City, UT (United States); Smith, P. [Univ. of Utah, Salt Lake City, UT (United States); Thornock, J. [Univ. of Utah, Salt Lake City, UT (United States); Y Jia, W. Morris [Univ. of Utah, Salt Lake City, UT (United States); Pedel, J. [Univ. of Utah, Salt Lake City, UT (United States); Rezeai, D. [Univ. of Utah, Salt Lake City, UT (United States); Wang, L. [Univ. of Utah, Salt Lake City, UT (United States); Zhang, J. [Univ. of Utah, Salt Lake City, UT (United States); Kelly, K. [Univ. of Utah, Salt Lake City, UT (United States)

    2012-01-06

    The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol.

  20. Steady state HNG combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Louwers, J.; Gadiot, G.M.H.J.L. [TNO Prins Maurits Lab., Rijswijk (Netherlands); Brewster, M.Q. [Univ. of Illinois, Urbana, IL (United States); Son, S.F. [Los Alamos National Lab., NM (United States); Parr, T.; Hanson-Parr, D. [Naval Air Warfare Center, China Lake, CA (United States)

    1998-04-01

    Two simplified modeling approaches are used to model the combustion of Hydrazinium Nitroformate (HNF, N{sub 2}H{sub 5}-C(NO{sub 2}){sub 3}). The condensed phase is treated by high activation energy asymptotics. The gas phase is treated by two limit cases: the classical high activation energy, and the recently introduced low activation energy approach. This results in simplification of the gas phase energy equation, making an (approximate) analytical solution possible. The results of both models are compared with experimental results of HNF combustion. It is shown that the low activation energy approach yields better agreement with experimental observations (e.g. regression rate and temperature sensitivity), than the high activation energy approach.

  1. Fundamental studies of spray combustion

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.C.; Libby, P.A.; Williams, F.A. [Univ. of California, San Diego, CA (United States)

    1997-12-31

    Our research on spray combustion involves both experiment and theory and addresses the characteristics of individual droplets and of sprays in a variety of flows: laminar and turbulent, opposed and impinging. Currently our focus concerns water and fuel sprays in two stage laminar flames, i.e., flames arising, for example from a stream of fuel and oxidizer flowing opposite to an air stream carrying a water spray. Our interest in these flames is motivated by the goals of reducing pollutant emissions and extending the range of stable spray combustion. There remains considerable research to be carried out in order to achieve these goals. Thus far our research on the characteristics of sprays in turbulent flows has been limited to nonreacting jets impinging on a plate but this work will be extended to opposed flows with and without a flame. In the following we discuss details of these studies and our plans for future work.

  2. SPECIFIC EMISSIONS FROM BIOMASS COMBUSTION

    Directory of Open Access Journals (Sweden)

    Pavel Skopec

    2014-02-01

    Full Text Available This paper deals with determining the specific emissions from the combustion of two kinds of biomass fuels in a small-scale boiler. The tested fuels were pellets made of wood and pellets made of rape plant straw. In order to evaluate the specific emissions, several combustion experiments were carried out using a commercial 25 kW pellet-fired boiler. The specific emissions of CO, SO2 and NOx were evaluated in relation to a unit of burned fuel, a unit of calorific value and a unit of produced heat. The specific emissions were compared with some data acquired from the reference literature, with relatively different results. The differences depend mainly on the procedure used for determining the values, and references provide no information about this. Although some of our experimental results may fit with one of the reference sources, they do not fit with the other. The reliability of the references is therefore disputable.

  3. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  4. Tabulated Combustion Model Development For Non-Premixed Flames

    Science.gov (United States)

    Kundu, Prithwish

    Turbulent non-premixed flames play a very important role in the field of engineering ranging from power generation to propulsion. The coupling of fluid mechanics and complicated combustion chemistry of fuels pose a challenge for the numerical modeling of these type of problems. Combustion modeling in Computational Fluid Dynamics (CFD) is one of the most important tools used for predictive modeling of complex systems and to understand the basic fundamentals of combustion. Traditional combustion models solve a transport equation of each species with a source term. In order to resolve the complex chemistry accurately it is important to include a large number of species. However, the computational cost is generally proportional to the cube of number of species. The presence of a large number of species in a flame makes the use of CFD computationally expensive and beyond reach for some applications or inaccurate when solved with simplified chemistry. For highly turbulent flows, it also becomes important to incorporate the effects of turbulence chemistry interaction (TCI). The aim of this work is to develop high fidelity combustion models based on the flamelet concept and to significantly advance the existing capabilities. A thorough investigation of existing models (Finite-rate chemistry and Representative Interactive Flamelet (RIF)) and comparative study of combustion models was done initially on a constant volume combustion chamber with diesel fuel injection. The CFD modeling was validated with experimental results and was also successfully applied to a single cylinder diesel engine. The effect of number of flamelets on the RIF model and flamelet initialization strategies were studied. The RIF model with multiple flamelets is computationally expensive and a model was proposed on the frame work of RIF. The new model was based on tabulated chemistry and incorporated TCI effects. A multidimensional tabulated chemistry database generation code was developed based on the 1

  5. The FCF Combustion Integrated Rack: Microgravity Combustion Science Onboard the International Space Station

    Science.gov (United States)

    OMalley, Terence F.; Weiland, Karen J.

    2002-01-01

    The Combustion Integrated Rack (CIR) is one of three facility payload racks being developed for the International Space Station (ISS) Fluids and Combustion Facility (FCF). Most microgravity combustion experiments will be performed onboard the Space Station in the Combustion Integrated Rack. Experiment-specific equipment will be installed on orbit in the CIR to customize it to perform many different scientific experiments during the ten or more years that it will operate on orbit. This paper provides an overview of the CIR, including a description of its preliminary design and planned accommodations for microgravity combustion science experiments, and descriptions of the combustion science experiments currently planned for the CIR.

  6. Universal Rateless Codes From Coupled LT Codes

    CERN Document Server

    Aref, Vahid

    2011-01-01

    It was recently shown that spatial coupling of individual low-density parity-check codes improves the belief-propagation threshold of the coupled ensemble essentially to the maximum a posteriori threshold of the underlying ensemble. We study the performance of spatially coupled low-density generator-matrix ensembles when used for transmission over binary-input memoryless output-symmetric channels. We show by means of density evolution that the threshold saturation phenomenon also takes place in this setting. Our motivation for studying low-density generator-matrix codes is that they can easily be converted into rateless codes. Although there are already several classes of excellent rateless codes known to date, rateless codes constructed via spatial coupling might offer some additional advantages. In particular, by the very nature of the threshold phenomenon one expects that codes constructed on this principle can be made to be universal, i.e., a single construction can uniformly approach capacity over the cl...

  7. Software Certification - Coding, Code, and Coders

    Science.gov (United States)

    Havelund, Klaus; Holzmann, Gerard J.

    2011-01-01

    We describe a certification approach for software development that has been adopted at our organization. JPL develops robotic spacecraft for the exploration of the solar system. The flight software that controls these spacecraft is considered to be mission critical. We argue that the goal of a software certification process cannot be the development of "perfect" software, i.e., software that can be formally proven to be correct under all imaginable and unimaginable circumstances. More realistically, the goal is to guarantee a software development process that is conducted by knowledgeable engineers, who follow generally accepted procedures to control known risks, while meeting agreed upon standards of workmanship. We target three specific issues that must be addressed in such a certification procedure: the coding process, the code that is developed, and the skills of the coders. The coding process is driven by standards (e.g., a coding standard) and tools. The code is mechanically checked against the standard with the help of state-of-the-art static source code analyzers. The coders, finally, are certified in on-site training courses that include formal exams.

  8. CSIR helps prevent spontaneous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Vuuren, M. van (CSIR Energy Technology (South Africa))

    1992-03-01

    Heaps of stockpiled coal could present a fire hazard due to the risk of spontaneous combustion. Regular monitoring of stockpiles and bunker testing of coals help to prevent stockpile fires. This brief article describes the recent upgrading of the CSIR's bunker test facility that enables coal producers, users and exporters to test their products under simulated conditions that duplicate the actual conditions under which coal is stored. 2 photos.

  9. Radiation/Catalytic Augmented Combustion.

    Science.gov (United States)

    1980-09-01

    NATIO& NAk H(fJI At tl TANUAHTOb 19 A ~omm.81-0287 LVL RADIATION/CATALYTIC AUGMENTED COMBUST ION MOSHE LAVID CORPORATE RESEARCH-TECHNOLOGY FEASIBILITY...refinements as necessary. i. Perform cannular combustor experiments to Investigate ignition and flame attachment in flowing, liquid -fuel, unpremixed...stabilizer, with a sintered metal disk on the downstream side through which hot gases or products of partial fuel oxidation can be passed. Experimental

  10. Laser Optics/Combustion Diagnostics.

    Science.gov (United States)

    1986-07-01

    been demonstrated. CARS measurements of axial and 0.12 radial temperature profiles in a highly sooting flame compared favorably with profiles...of Number-Density Equation ’Eckbreth. A.C. and Hatt. R.., "CARS Thermomrry in a The third-order susceptibility can be rewritten to show its Sooting ... Flame ." Combustion and Homie, Vol. 36. 1979, pp. 87-98. explcitdepndece ponthenumer ensty Roh. %W.B.. "Coherent Anti-Stokcs Raman Scattering ofexpici

  11. ABB Combustion Engineering nuclear technology

    Energy Technology Data Exchange (ETDEWEB)

    Matzie, R.A.

    1994-12-31

    The activities of ABB Combustion Engineering in the design and construction of nuclear systems and components are briefly reviewed. ABB Construction Engineering continues to improve the design and design process for nuclear generating stations. Potential improvements are evaluated to meet new requirements both of the public and the regulator, so that the designs meet the highest standards worldwide. Advancements necessary to meet market needs and to ensure the highest level of performance in the future will be made.

  12. Vortex Simulation of Turbulent Combustion

    Science.gov (United States)

    1992-11-19

    TURBULENT COMBUSTION (AFOSR Grant No. 89-0491) Principal Investigator: Ahmed F. Ghoniem Department of Mechanical Engineering Massachusetts Institute of...Heavy Industries, Nagoya, Japan.(talk and discussion). 17. 1990, Mazda Motor Co., Yokohama, Japan, (talk and discussion). 18. 1990, American Math Society...VORTICITY LAYERS UNDER NON-SYMMETRIC CONDITIONS Omar M. Kniot and Ahmed F. Ghoniem Department of Mechanical Engineering Massachusetts Institute of

  13. Nitrogen release during coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L.; Mitchell, R.E.; Fletcher, T.H.; Hurt, R.H.

    1995-02-01

    Experiments in entrained flow reactors at combustion temperatures are performed to resolve the rank dependence of nitrogen release on an elemental basis for a suite of 15 U.S. coals ranging from lignite to low-volatile bituminous. Data were obtained as a function of particle conversion, with overall mass loss up to 99% on a dry, ash-free basis. Nitrogen release rates are presented relative to both carbon loss and overall mass loss. During devolatilization, fractional nitrogen release from low-rank coals is much slower than fractional mass release and noticeably slower than fractional carbon release. As coal rank increases, fractional nitrogen release rate relative to that of carbon and mass increases, with fractional nitrogen release rates exceeding fractional mass and fractional carbon release rates during devolatilization for high-rank (low-volatile bituminous) coals. At the onset of combustion, nitrogen release rates increase significantly. For all coals investigated, cumulative fractional nitrogen loss rates relative to those of mass and carbon passes through a maximum during the earliest stages of oxidation. The mechanism for generating this maximum is postulated to involve nascent thermal rupture of nitrogen-containing compounds and possible preferential oxidation of nitrogen sites. During later stages of oxidation, the cumulative fractional loss of nitrogen approaches that of carbon for all coals. Changes in the relative release rates of nitrogen compared to those of both overall mass and carbon during all stages of combustion are attributed to a combination of the chemical structure of coals, temperature histories during combustion, and char chemistry.

  14. A CFD model for biomass combustion in a packed bed furnace

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Md. Rezwanul [Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC 3122 (Australia); Department of Mechanical & Chemical Engineering, Islamic University of Technology, Gazipur 1704 (Bangladesh); Ovi, Ifat Rabbil Qudrat [Department of Mechanical & Chemical Engineering, Islamic University of Technology, Gazipur 1704 (Bangladesh); Naser, Jamal, E-mail: jnaser@swin.edu.au [Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC 3122 (Australia)

    2016-07-12

    Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO{sub 2} emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is the most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can’t model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.

  15. A CFD model for biomass combustion in a packed bed furnace

    Science.gov (United States)

    Karim, Md. Rezwanul; Ovi, Ifat Rabbil Qudrat; Naser, Jamal

    2016-07-01

    Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO2 emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is the most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can't model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.

  16. Combustion char characterisation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, P.; Ingermann Petersen, H.; Sund Soerensen, H.; Thomsen, E.; Guvad, C.

    1996-06-01

    The aim was to correlate reactivity measures of raw coals and the maceral concentrates of the coals obtained in a previous project with the morphology of the produced chars by using a wire grid devolatilization method. Work involved determination of morphology, macroporosity and a detailed study by Scanning Electron Microscopy (SEM). Systematic variations in the texture of chars produced in different temperature domains and heating rates were demonstrated by using incident light microscopy on polished blocks and by SEM studies directly on the surfaces of untreated particles. Results suggest that work in the field of char reactivity estimates and correlations between char morphology and coal petrography can be accomplished only on chars produced under heating rates and temperatures comparable to those for the intended use of coal. A general correlation between the coals` petrography and the the morphology of high temperature chars was found. The SEM study of the chars revealed that during the devolatilization period the particles fuse and the macroporosity and thus the morphotypes are formed. After devolatilization ceases, secondary micropores are formed. These develop in number and size throughout the medium combustion interval. At the end of the combustion interval the macrostructure breaks down, caused by coalescence of the increased number of microspores. This can be observed as a change in the morphology and the macroporosity of the chars. Results indicate that char reactivity is a function of the macroporosity and thus the morphology of combustion chars. (AB) 34 refs.

  17. Demonstration of Active Combustion Control

    Science.gov (United States)

    Lovett, Jeffrey A.; Teerlinck, Karen A.; Cohen, Jeffrey M.

    2008-01-01

    The primary objective of this effort was to demonstrate active control of combustion instabilities in a direct-injection gas turbine combustor that accurately simulates engine operating conditions and reproduces an engine-type instability. This report documents the second phase of a two-phase effort. The first phase involved the analysis of an instability observed in a developmental aeroengine and the design of a single-nozzle test rig to replicate that phenomenon. This was successfully completed in 2001 and is documented in the Phase I report. This second phase was directed toward demonstration of active control strategies to mitigate this instability and thereby demonstrate the viability of active control for aircraft engine combustors. This involved development of high-speed actuator technology, testing and analysis of how the actuation system was integrated with the combustion system, control algorithm development, and demonstration testing in the single-nozzle test rig. A 30 percent reduction in the amplitude of the high-frequency (570 Hz) instability was achieved using actuation systems and control algorithms developed within this effort. Even larger reductions were shown with a low-frequency (270 Hz) instability. This represents a unique achievement in the development and practical demonstration of active combustion control systems for gas turbine applications.

  18. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1995-10-01

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.

  19. Modeling the internal combustion engine

    Science.gov (United States)

    Zeleznik, F. J.; Mcbride, B. J.

    1985-01-01

    A flexible and computationally economical model of the internal combustion engine was developed for use on large digital computer systems. It is based on a system of ordinary differential equations for cylinder-averaged properties. The computer program is capable of multicycle calculations, with some parameters varying from cycle to cycle, and has restart capabilities. It can accommodate a broad spectrum of reactants, permits changes in physical properties, and offers a wide selection of alternative modeling functions without any reprogramming. It readily adapts to the amount of information available in a particular case because the model is in fact a hierarchy of five models. The models range from a simple model requiring only thermodynamic properties to a complex model demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. Among its many features the model includes heat transfer, valve timing, supercharging, motoring, finite burning rates, cycle-to-cycle variations in air-fuel ratio, humid air, residual and recirculated exhaust gas, and full combustion kinetics.

  20. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Clifford E. Smith; Steven M. Cannon; Virgil Adumitroaie; David L. Black; Karl V. Meredith

    2005-01-01

    to hundreds of PCs and performing parallel computations with fine grids (millions of cells). Such simulations, performed in a few weeks or less, provide a very cost-effective complement to experimental testing. In 5 years, these same calculations can be performed in 24 hours or less due to the expected increase of computing power and improved numerical techniques. This project was a four-year program. During the first year, the project included the development and implementation of improved chemistry (reduced GRI mechanism), subgrid turbulence (localized dynamic), and subgrid combustion-turbulence interaction (Linear Eddy) models into the CFD-ACE+ code. University expertise (Georgia Tech and University of California, Berkeley) was utilized to help develop and implement these advanced submodels into the unstructured, parallel CFD flow solver, CFD-ACE+. Efficient numerical algorithms that rely on in situ look-up tables or artificial neural networks were implemented for chemistry calculations. In the second year, the combustion LES software was evaluated and validated using experimental data from lab-scale and industrial test configurations. This code testing (i.e., alpha testing) was performed by CFD Research Corporation's engineers. During the third year, six industrial and academic partners used the combustion LES code and exercised it on problems of their choice (i.e., beta testing). Final feedback and optimizations were then implemented into the final release (licensed) version of the combustion LES software to the general public. An additional one-year task was added for the fourth year of this program entitled, ''LES Simulations of SIMVAL Results''. For this task, CFDRC performed LES calculations of selected DoE SIMVAL cases, and compared predictions with measurements from NETL. In addition to comparisons with NOx and CO exit measurements, comparisons were made to measured pressure oscillations. Potential areas of improvement for

  1. Coding for Electronic Mail

    Science.gov (United States)

    Rice, R. F.; Lee, J. J.

    1986-01-01

    Scheme for coding facsimile messages promises to reduce data transmission requirements to one-tenth current level. Coding scheme paves way for true electronic mail in which handwritten, typed, or printed messages or diagrams sent virtually instantaneously - between buildings or between continents. Scheme, called Universal System for Efficient Electronic Mail (USEEM), uses unsupervised character recognition and adaptive noiseless coding of text. Image quality of resulting delivered messages improved over messages transmitted by conventional coding. Coding scheme compatible with direct-entry electronic mail as well as facsimile reproduction. Text transmitted in this scheme automatically translated to word-processor form.

  2. Numerical calculation of combustion and heat transfer in furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Grimsmo, B.; Lilleheie, N.I. [ComputIT (Norway)

    2001-07-01

    Advanced simulations have been used to optimise the retrofit of actual furnaces resulting in a 75 % reduction in NO{sub x} emissions. The simulations have been performed with the CFD code KAMELEON. The calculation method is based on a three-dimensional finite-volume solution of the Favre-averaged equations of fluid dynamics together with models for turbulence, combustion, soot, radiation, and formation of pollutants. Among these models, the EDC model of Magnussen is of particular importance. In this concept, the combustion mechanism is assumed closely related to the classical turbulence transfer and break-up theory. A criteria for combustion to take place is that fuel and air have to be mixed on a molecular level and that the mixture has to be sufficiently heated to react. With the EDC model, it is possible to handle the inhomogeneity in turbulent combustion. The high temperature in the fine structures and low-temperature phenomena in the surroundings are treated simultaneously. This approach corresponds to a bi-modal pdf. The inhomogeneous temperature and composition in turbulent flames have an important influence on the formation of soot and NO{sub x}. This is readily taken into account within the framework of the EDC model. For improved accuracy, the inhomogeneity is also taken into account when computing radiative heat transfer. A table-lookup technique is used to predict NO{sub x} formation. The methods used have been verified by comparisons with measurements in well-defined laboratory flames. By means of this simulation tool it is possible to reveal wanted and unwanted effects on the furnace, as well as on the environment. It will also be possible to foretell the effect of changes in design and operation parameters and hence be able to adopt the optimum configuration for high efficiency, reliability and low emissions.

  3. COMBUSTION SIMULATION IN A SPARK IGNITION ENGINE CYLINDER: EFFECTS OF AIR-FUEL RATIO ON THE COMBUSTION DURATION

    OpenAIRE

    2010-01-01

    Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion...

  4. Noisy Network Coding

    CERN Document Server

    Lim, Sung Hoon; Gamal, Abbas El; Chung, Sae-Young

    2010-01-01

    A noisy network coding scheme for sending multiple sources over a general noisy network is presented. For multi-source multicast networks, the scheme naturally extends both network coding over noiseless networks by Ahlswede, Cai, Li, and Yeung, and compress-forward coding for the relay channel by Cover and El Gamal to general discrete memoryless and Gaussian networks. The scheme also recovers as special cases the results on coding for wireless relay networks and deterministic networks by Avestimehr, Diggavi, and Tse, and coding for wireless erasure networks by Dana, Gowaikar, Palanki, Hassibi, and Effros. The scheme involves message repetition coding, relay signal compression, and simultaneous decoding. Unlike previous compress--forward schemes, where independent messages are sent over multiple blocks, the same message is sent multiple times using independent codebooks as in the network coding scheme for cyclic networks. Furthermore, the relays do not use Wyner--Ziv binning as in previous compress-forward sch...

  5. Testing algebraic geometric codes

    Institute of Scientific and Technical Information of China (English)

    CHEN Hao

    2009-01-01

    Property testing was initially studied from various motivations in 1990's.A code C (∩)GF(r)n is locally testable if there is a randomized algorithm which can distinguish with high possibility the codewords from a vector essentially far from the code by only accessing a very small (typically constant) number of the vector's coordinates.The problem of testing codes was firstly studied by Blum,Luby and Rubinfeld and closely related to probabilistically checkable proofs (PCPs).How to characterize locally testable codes is a complex and challenge problem.The local tests have been studied for Reed-Solomon (RS),Reed-Muller (RM),cyclic,dual of BCH and the trace subcode of algebraicgeometric codes.In this paper we give testers for algebraic geometric codes with linear parameters (as functions of dimensions).We also give a moderate condition under which the family of algebraic geometric codes cannot be locally testable.

  6. Chinese remainder codes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Aili; LIU Xiufeng

    2006-01-01

    Chinese remainder codes are constructed by applying weak block designs and the Chinese remainder theorem of ring theory.The new type of linear codes take the congruence class in the congruence class ring R/I1 ∩ I2 ∩…∩ In for the information bit,embed R/Ji into R/I1 ∩ I2 ∩…∩ In,and assign the cosets of R/Ji as the subring of R/I1 ∩ I2 ∩…∩ In and the cosets of R/Ji in R/I1 ∩ I2 ∩…∩ In as check lines.Many code classes exist in the Chinese remainder codes that have high code rates.Chinese remainder codes are the essential generalization of Sun Zi codes.

  7. Chinese Remainder Codes

    Institute of Scientific and Technical Information of China (English)

    张爱丽; 刘秀峰; 靳蕃

    2004-01-01

    Chinese Remainder Codes are constructed by applying weak block designs and Chinese Remainder Theorem of ring theory. The new type of linear codes take the congruence class in the congruence class ring R/I1∩I2∩…∩In for the information bit, embed R/Ji into R/I1∩I2∩…∩In, and asssign the cosets of R/Ji as the subring of R/I1∩I2∩…∩In and the cosets of R/Ji in R/I1∩I2∩…∩In as check lines. There exist many code classes in Chinese Remainder Codes, which have high code rates. Chinese Remainder Codes are the essential generalization of Sun Zi Codes.

  8. Code of Ethics

    DEFF Research Database (Denmark)

    Adelstein, Jennifer; Clegg, Stewart

    2016-01-01

    Ethical codes have been hailed as an explicit vehicle for achieving more sustainable and defensible organizational practice. Nonetheless, when legal compliance and corporate governance codes are conflated, codes can be used to define organizational interests ostentatiously by stipulating norms...... for employee ethics. Such codes have a largely cosmetic and insurance function, acting subtly and strategically to control organizational risk management and protection. In this paper, we conduct a genealogical discourse analysis of a representative code of ethics from an international corporation...... to understand how management frames expectations of compliance. Our contribution is to articulate the problems inherent in codes of ethics, and we make some recommendations to address these to benefit both an organization and its employees. In this way, we show how a code of ethics can provide a foundation...

  9. Defeating the coding monsters.

    Science.gov (United States)

    Colt, Ross

    2007-02-01

    Accuracy in coding is rapidly becoming a required skill for military health care providers. Clinic staffing, equipment purchase decisions, and even reimbursement will soon be based on the coding data that we provide. Learning the complicated myriad of rules to code accurately can seem overwhelming. However, the majority of clinic visits in a typical outpatient clinic generally fall into two major evaluation and management codes, 99213 and 99214. If health care providers can learn the rules required to code a 99214 visit, then this will provide a 90% solution that can enable them to accurately code the majority of their clinic visits. This article demonstrates a step-by-step method to code a 99214 visit, by viewing each of the three requirements as a monster to be defeated.

  10. Testing algebraic geometric codes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Property testing was initially studied from various motivations in 1990’s. A code C  GF (r)n is locally testable if there is a randomized algorithm which can distinguish with high possibility the codewords from a vector essentially far from the code by only accessing a very small (typically constant) number of the vector’s coordinates. The problem of testing codes was firstly studied by Blum, Luby and Rubinfeld and closely related to probabilistically checkable proofs (PCPs). How to characterize locally testable codes is a complex and challenge problem. The local tests have been studied for Reed-Solomon (RS), Reed-Muller (RM), cyclic, dual of BCH and the trace subcode of algebraicgeometric codes. In this paper we give testers for algebraic geometric codes with linear parameters (as functions of dimensions). We also give a moderate condition under which the family of algebraic geometric codes cannot be locally testable.

  11. Serially Concatenated IRA Codes

    CERN Document Server

    Cheng, Taikun; Belzer, Benjamin J

    2007-01-01

    We address the error floor problem of low-density parity check (LDPC) codes on the binary-input additive white Gaussian noise (AWGN) channel, by constructing a serially concatenated code consisting of two systematic irregular repeat accumulate (IRA) component codes connected by an interleaver. The interleaver is designed to prevent stopping-set error events in one of the IRA codes from propagating into stopping set events of the other code. Simulations with two 128-bit rate 0.707 IRA component codes show that the proposed architecture achieves a much lower error floor at higher SNRs, compared to a 16384-bit rate 1/2 IRA code, but incurs an SNR penalty of about 2 dB at low to medium SNRs. Experiments indicate that the SNR penalty can be reduced at larger blocklengths.

  12. Effect of a lotion containing the heat-treated probiotic strain Lactobacillus johnsonii NCC 533 on Staphylococcus aureus colonization in atopic dermatitis.

    Science.gov (United States)

    Blanchet-Réthoré, Sandrine; Bourdès, Valérie; Mercenier, Annick; Haddar, Cyrille H; Verhoeven, Paul O; Andres, Philippe

    2017-01-01

    Staphylococcus aureus dominates the skin microbiota in patients with atopic dermatitis (AD), with bacterial loads correlating with disease severity. The aim of this exploratory study was to investigate the effect of a cosmetic lotion containing heat-treated Lactobacillus johnsonii NCC 533 (HT La1) on S. aureus colonization in AD patients. This open-label, multicenter study was performed in AD patients in Germany. First, detection of S. aureus was performed in all patients using the swab or scrub-wash method of sampling, followed by quantitative culture or quantitative polymerase chain reaction. Repeatability and reproducibility of all method combinations were evaluated to select the best combination of sampling and quantification. Second, a lotion containing HT La1 was applied to lesional skin twice daily for 3 weeks. Scoring using local objective SCORing Atopic Dermatitis (SCORAD), measurement of S. aureus load, and lesional microbiome analysis were performed before and after the 3-week treatment period. Thirty-one patients with AD were included in the study. All sampling and quantification methods were found to be robust, reproducible, and repeatable for assessing S. aureus load. For simplicity, a combination of swab and quantitative polymerase chain reaction was chosen to assess the efficacy of HT La1. Following application of a lotion containing HT La1 to AD lesions for 3 weeks, a reduction in S. aureus load was observed in patients, which correlated with a decrease in local objective SCORAD. Interestingly, high baseline skin concentrations of S. aureus were associated with good responses to the lotion. This study demonstrated that the application of a lotion containing HT La1 to the lesional skin of patients with AD for 3 weeks controlled S. aureus colonization and was associated with local clinical improvement (SCORAD). These findings support further development of topical treatments containing heat-treated nonreplicating beneficial bacteria for patients with

  13. Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Szpila, Aneta; Bohgard, Mats [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Div. of Bioenergy Technology; Pagels, Joakim; Rissler, Jenny; Swietlicki, Erik; Gharibi, Arash [Lund Univ. (Sweden). Div. of Nuclear Physics

    2003-05-01

    We have shown that high concentrations of fine particles of the order of 2-7x10{sup -7} particles per cm{sup 3} are being formed in all the combustion units studied. There was a higher difference between the units in terms of particle mass concentrations. While the largest differences was found for gas-phase constituents (CO and THC) and polyaromatic hydrocarbons. In 5 out of 7 studied units, multi-cyclones were the only measure for flue-gas separation. The multicyclones had negligible effect on the particle number concentration and a small effect on the mass of particles smaller than 5 {mu}m. The separation efficiency was much higher for the electrostatic precipitators. The boiler load had a dramatic influence on the coarse mode concentration during combustion of forest residue. PM0.8-6 increased from below 5 mg/m{sup 3} to above 50 mg/m{sup 3} even at a moderate change in boiler load from medium to high. A similar but less pronounced trend was found during combustion of dry wood. PM0.8-PM6 increased from 12 to 23 mg/m{sup 3} when the load was changed from low to high. When increasing the load, the primary airflow taken through the grate is increased; this itself may lead to a higher potential of the air stream to carry coarse particles away from the combustion zone. Measurements with APS-instrument with higher time-resolution showed a corresponding increase in coarse mode number concentration with load. Additional factor influencing observed higher concentration of coarse mode during combustion of forest residues, could be relatively high ash content in this type of fuel (2.2 %) in comparison to dry wood (0.3 %) and pellets (0.5 %). With increasing load we also found a decrease in PM1 during combustion of forest residue. Whether this is caused by scavenging of volatilized material by the high coarse mode concentration or a result of a different amount of volatilized material available for formation of fine particles needs to be shown in future studies. The

  14. TOXIC SUBSTANCES FROM COAL COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    A KOLKER; AF SAROFIM; CL SENIOR; FE HUGGINS; GP HUFFMAN; I OLMEZ; J LIGHTY; JOL WENDT; JOSEPH J HELBLE; MR AMES; N YAP; R FINKELMAN; T PANAGIOTOU; W SEAMES

    1998-12-08

    The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the Federal Energy Technology Center (FETC), the Electric Power Research Institute, the Lignite Research Council, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, MIT, the University of Arizona (UA), the University of Kentucky (UK), the University of Connecticut (UC), the University of Utah (UU) and the University of North Dakota Energy and Environmental Research Center (EERC) to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NO combustion systems, and new power generation x plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). This report covers the reporting period from 1 July 1998 through 30 September 1998. During this period distribution of all three Phase II coals was completed. Standard analyses for the whole coal samples were also completed. Mössbauer analysis of all project coals and fractions received to date has been completed in order to obtain details of the iron mineralogy. The analyses of arsenic XAFS data for two of the project coals and for some high arsenic coals have been completed. Duplicate splits of the Ohio 5,6,7 and North Dakota lignite samples were taken through all four steps of the selective leaching procedure. Leaching analysis of the Wyodak coal has recently commenced. Preparation of polished coal/epoxy pellets for probe/SEM studies is underway. Some exploratory mercury LIII XAFS work was

  15. Fuel oil combustion with low production of nitrogen oxides; Combustion de combustoleo con baja produccion de oxidos de nitrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Escalera Campoverde, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-09-01

    This work presents the results of the theoretical-experimental study of the effects of the secondary air jet directed perpendicularly to the flame axis in the fuel oil combustion in a 500 Kw furnace. The main purpose of this study was to obtain low nitrogen oxides (NO{sub x}) emissions without increasing the CO, which is observed in low NO{sub x} conventional burners. The experimental results showed a significative reduction of the NO{sub x} and of the CO, from 320 to 90 ppm and from 50 ppm to negligible values, respectively. A commercial computational code of fluid dynamics was employed for modeling the combustion in base line conditions, without secondary air and with the injection of secondary air. The experimental results were compared with calculated ones. [Espanol] En este trabajo se presentan los resultados del estudio teorico experimental de los efectos de los chorro de aire secundario dirigidos en forma perpendicular al eje de la flama en la combustion del combustoleo en un horno de 500 kW. El proposito principal del estudio fue obtener bajas emisiones de oxidos de nitrogeno (NO{sub x}) sin incrementar el CO, lo cual se observa en quemadores convencionales de bajo NO{sub x}. Los resultados experimentales demostraron una reduccion significativa del NO{sub x} y del CO: de 320 a 90 ppm y de 50 ppm a valores despreciables, respectivamente. Se empleo un codigo computacional comercial de dinamica de fluidos para modelar la combustion en condiciones de linea base, sin aire secundario, y con la inyeccion del aire secundario. Se comparan resultados experimentales con los calculados.

  16. Parametric HECTR calculations of hydrogen transport and combustion at N Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Payne, A.C. Jr.; Camp, A.L.

    1987-06-01

    This report describes a limited number of parametric calculations of hydrogen transport and combustion in the N Reactor confinement for selected accident sequences. The calculations are performed using the HECTR computer code, which is a lumped-parameter code developed specifically for evaluating hydrogen behavior in reactor containments. A number of parameters are evaluated in this study, including hydrogen source rate, spray effects, and source location. The calculations indicate that mixing within major compartments tends to occur fairly rapidly, but that mixing between compartments can be inhibited in certain situations, resulting in the formation of flammable mixtures. These results are being compared to calculations performed with other computer codes, including a code that uses finite-difference models. United Nuclear Corporation will present the results of these code comparisons in future reports.

  17. Sandia Combustion Research Program: Annual report, 1986

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    This report presents research results of the past year, divided thematically into some ten categories. Publications and presentations arising from this work are included in the appendix. Our highlighted accomplishment of the year is the announcement of the discovery and demonstration of the RAPRENOx process. This new mechanism for the elimination of nitrogen oxides from essentially all kinds of combustion exhausts shows promise for commercialization, and may eventually make a significant contribution to our nation's ability to control smog and acid rain. The sections of this volume describe the facility's laser and computer system, laser diagnostics of flames, combustion chemistry, reacting flows, liquid and solid propellant combustion, mathematical models of combustion, high-temperature material interfaces, studies of engine/furnace combustion, coal combustion, and the means of encouraging technology transfer. 182 refs., 170 figs., 12 tabs.

  18. Straw combustion on slow-moving grates

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2005-01-01

    Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ‘‘walking......-column’’ approach and includes the energy equations for both the fuel and the gas accounting for heat transfer between the two phases. The model gives important insight into the combustion process and provides inlet conditions for a computational fluid dynamics analysis of the freeboard. The model predictions...... indicate the existence of two distinct combustion modes. Combustion air temperature and mass flow-rate are the two parameters determining the mode. There is a significant difference in reaction rates (ignition velocity) and temperature levels between the two modes. Model predictions were compared...

  19. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    QI Qing-jie; LIN Zhi-yan; LIU Jian-zhong; WU Xian; ZHOU Jun-hu; CEN Ke-fa

    2008-01-01

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

  20. Fuel combustion test in constant volume combustion chamber with built-in adaptor

    Institute of Scientific and Technical Information of China (English)

    JEONG; DongSoo; CHO; GyuBack; CHOI; SuJin; LEE; JinSoo

    2010-01-01

    Combustion tests of pre-mixture of methane and air in constant volume combustion chamber(CVCC) have been carried out by means of flame propagation photo and gas pressure measurement,the effects of CVCC body temperature,intake pressure of pre-mixture of methane and air,equivalence ratio and location of the built-in adaptor have been investigated.The whole combustion chamber can be divided into two parts,i.e.the upper combustion chamber and the lower combustion chamber,by the built-in adaptor with through hole.Owing to the built-in adaptor with through hole,jet ignition or compression ignition(auto-ignition) phenomena may occur in the lower combustion chamber,which is helpful to getting higher flame propagation velocity,higher combustion peak pressure,low cycle-to-cycle variation and more stable combustion process.