Relevant bibliographies by topics / Chemistry and transport model

Academic literature on the topic 'Chemistry and transport model'

Author: Grafiati
Published: 9 March 2023
Last updated: 10 March 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Chemistry and transport model.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Chemistry and transport model"

1

Wohltmann, I., and M. Rex. "The Lagrangian chemistry and transport model ATLAS: validation of transport and mixing." Geoscientific Model Development Discussions 2, no. 2 (July 3, 2009): 709–62. http://dx.doi.org/10.5194/gmdd-2-709-2009.

Full text
Abstract:
Abstract. We present a new global Chemical Transport Model (CTM) with full stratospheric chemistry and Lagrangian transport and mixing called ATLAS (Alfred Wegener InsTitute LAgrangian Chemistry/Transport System). Lagrangian (trajectory-based) models have several important advantages over conventional Eulerian (grid-based) models, including the absence of spurious numerical diffusion, efficient code parallelization and no limitation of the largest time step by the Courant-Friedrichs-Lewy criterion. The basic concept of transport and mixing is similar to the approach in the commonly used CLaMS model. Several aspects of the model are different from CLaMS and are introduced and validated here, including a different mixing algorithm which is less diffusive and agrees better with observations with the same mixing parameters. In addition, values for the vertical and horizontal stratospheric bulk diffusion coefficients are inferred and compared to other studies. This work focusses on the description of the dynamical part of the model and the validation of the mixing algorithm. The overall model including the chemistry module, which contains 49 species, 170 reactions and a detailed treatment of heterogeneous chemistry, will be presented in a separate paper.
APA, Harvard, Vancouver, ISO, and other styles
2

Wohltmann, I., and M. Rex. "The Lagrangian chemistry and transport model ATLAS: validation of advective transport and mixing." Geoscientific Model Development 2, no. 2 (November 2, 2009): 153–73. http://dx.doi.org/10.5194/gmd-2-153-2009.

Full text
Abstract:
Abstract. We present a new global Chemical Transport Model (CTM) with full stratospheric chemistry and Lagrangian transport and mixing called ATLAS (Alfred Wegener InsTitute LAgrangian Chemistry/Transport System). Lagrangian (trajectory-based) models have several important advantages over conventional Eulerian (grid-based) models, including the absence of spurious numerical diffusion, efficient code parallelization and no limitation of the largest time step by the Courant-Friedrichs-Lewy criterion. The basic concept of transport and mixing is similar to the approach in the commonly used CLaMS model. Several aspects of the model are different from CLaMS and are introduced and validated here, including a different mixing algorithm for lower resolutions which is less diffusive and agrees better with observations with the same mixing parameters. In addition, values for the vertical and horizontal stratospheric bulk diffusion coefficients are inferred and compared to other studies. This work focusses on the description of the dynamical part of the model and the validation of the mixing algorithm. The chemistry module, which contains 49 species, 170 reactions and a detailed treatment of heterogeneous chemistry, will be presented in a separate paper.
APA, Harvard, Vancouver, ISO, and other styles
3

Riede, H., P. Jöckel, and R. Sander. "Quantifying atmospheric transport, chemistry, and mixing using a new trajectory-box model and a global atmospheric-chemistry GCM." Geoscientific Model Development 2, no. 2 (December 15, 2009): 267–80. http://dx.doi.org/10.5194/gmd-2-267-2009.

Full text
Abstract:
Abstract. We present a novel method for the quantification of transport, chemistry, and mixing along atmospheric trajectories based on a consistent model hierarchy. The hierarchy consists of the new atmospheric-chemistry trajectory-box model CAABA/MJT and the three-dimensional (3-D) global ECHAM/MESSy atmospheric-chemistry (EMAC) general circulation model. CAABA/MJT employs the atmospheric box model CAABA in a configuration using the atmospheric-chemistry submodel MECCA (M), the photochemistry submodel JVAL (J), and the new trajectory submodel TRAJECT (T), to simulate chemistry along atmospheric trajectories, which are provided offline. With the same chemistry submodels coupled to the 3-D EMAC model and consistent initial conditions and physical parameters, a unique consistency between the two models is achieved. Since only mixing processes within the 3-D model are excluded from the model consistency, comparisons of results from the two models allow to separate and quantify contributions of transport, chemistry, and mixing along the trajectory pathways. Consistency of transport between the trajectory-box model CAABA/MJT and the 3-D EMAC model is achieved via calculation of kinematic trajectories based on 3-D wind fields from EMAC using the trajectory model LAGRANTO. The combination of the trajectory-box model CAABA/MJT and the trajectory model LAGRANTO can be considered as a Lagrangian chemistry-transport model (CTM) moving isolated air parcels. The procedure for obtaining the necessary statistical basis for the quantification method is described as well as the comprehensive diagnostics with respect to chemistry. The quantification method presented here allows to investigate the characteristics of transport, chemistry, and mixing in a grid-based 3-D model. The analysis of chemical processes within the trajectory-box model CAABA/MJT is easily extendable to include, for example, the impact of different transport pathways or of mixing processes onto chemistry. Under certain prerequisites described here, the results can be used to complement observations with detailed information about the history of observed air masses.
APA, Harvard, Vancouver, ISO, and other styles
4

Deckert, R., P. Jöckel, V. Grewe, K. D. Gottschaldt, and P. Hoor. "A quasi chemistry-transport model mode for EMAC." Geoscientific Model Development Discussions 3, no. 4 (November 19, 2010): 2189–220. http://dx.doi.org/10.5194/gmdd-3-2189-2010.

Full text
Abstract:
Abstract. A quasi chemistry-transport model mode (QCTM) is presented for the numerical chemistry-climate simulation system ECHAM/MESSy Atmospheric Chemistry (EMAC). It allows for a quantification of chemical signals through suppression of any feedback between chemistry and dynamics. Noise would otherwise interfere too strongly. The signal follows from the difference of two QCTM simulations, reference and sensitivity. These are fed with offline chemical fields as a substitute of the feedbacks between chemistry and dynamics: offline mixing ratios of radiatively active substances enter the radiation scheme (a), offline mixing ratios of nitric acid enter the scheme for re-partitioning and sedimentation from polar stratospheric clouds (b). Offline methane oxidation is the exclusive source of chemical water-vapor tendencies (c). Any set of offline fields suffices to suppress the feedbacks, though may be inconsistent with the simulation setup. An adequate set of offline climatologies can be produced from a non-QCTM simulation of the reference setup. Test simulations reveal the particular importance of adequate offline fields associated with (a). Inconsistencies from (b) are negligible when using adequate fields of nitric acid. Acceptably small inconsistencies come from (c), but should vanish for an adequate prescription of water vapor tendencies. Toggling between QCTM and non-QCTM is done via namelist switches and does not require a source code re-compilation.
APA, Harvard, Vancouver, ISO, and other styles
5

Menut, Laurent, Bertrand Bessagnet, Régis Briant, Arineh Cholakian, Florian Couvidat, Sylvain Mailler, Romain Pennel, et al. "The CHIMERE v2020r1 online chemistry-transport model." Geoscientific Model Development 14, no. 11 (November 5, 2021): 6781–811. http://dx.doi.org/10.5194/gmd-14-6781-2021.

Full text
Abstract:
Abstract. The CHIMERE chemistry-transport model v2020r1 replaces the v2017r5 version and provides numerous novelties. The most important of these is the online coupling with the Weather Research and Forecasting (WRF) meteorological model via the OASIS3 – Model Coupling Toolkit (MCT) external coupler. The model can still be used in offline mode; the online mode enables us to take into account the direct and indirect effects of aerosols on meteorology. This coupling also enables using the meteorological parameters with sub-hourly time steps. Some new parameterizations are implemented to increase the model performance and the user's choices: dimethyl sulfide (DMS) emissions, additional schemes for secondary organic aerosol (SOA) formation with volatility basis set (VBS) and H2O, improved schemes for mineral dust, biomass burning, and sea-salt emissions. The NOx emissions from lightning are added. The model also includes the possibility to use the operator-splitting integration technique. The subgrid-scale variability calculation of concentrations due to emission activity sectors is now possible. Finally, a new vertical advection scheme has been implemented, which is able to simulate more correctly long-range transport of thin pollutant plumes.
APA, Harvard, Vancouver, ISO, and other styles
6

Deckert, R., P. Jöckel, V. Grewe, K. D. Gottschaldt, and P. Hoor. "A quasi chemistry-transport model mode for EMAC." Geoscientific Model Development 4, no. 1 (March 16, 2011): 195–206. http://dx.doi.org/10.5194/gmd-4-195-2011.

Full text
Abstract:
Abstract. A quasi chemistry-transport model mode (QCTM) is presented for the numerical chemistry-climate simulation system ECHAM/MESSy Atmospheric Chemistry (EMAC). It allows for a quantification of chemical signals through suppression of any feedback between chemistry and dynamics. Noise would otherwise interfere too strongly. The signal is calculated from the difference of two QCTM simulations, a reference simulation and a sensitivity simulation. In order to avoid the feedbacks, the simulations adopt the following offline chemical fields: (a) offline mixing ratios of radiatively active substances enter the radiation scheme, (b) offline mixing ratios of nitric acid enter the scheme for re-partitioning and sedimentation from polar stratospheric clouds, (c) and offline methane oxidation is the exclusive source of chemical water-vapor tendencies. Any set of offline fields suffices to suppress the feedbacks, though may be inconsistent with the simulation setup. An adequate set of offline climatologies can be produced from a non-QCTM simulation using the setup of the reference simulation. Test simulations reveal the particular importance of adequate offline fields associated with (a). Inconsistencies from (b) are negligible when using adequate fields of nitric acid. Acceptably small inconsistencies come from (c), but should vanish for an adequate prescription of chemical water vapor tendencies. Toggling between QCTM and non-QCTM is done via namelist switches and does not require a source code re-compilation.
APA, Harvard, Vancouver, ISO, and other styles
7

Jung, G., I. M. Hedgecock, and N. Pirrone. "ECHMERIT V1.0 – a new global fully coupled mercury-chemistry and transport model." Geoscientific Model Development Discussions 2, no. 1 (May 7, 2009): 385–453. http://dx.doi.org/10.5194/gmdd-2-385-2009.

Full text
Abstract:
Abstract. Mercury is a global pollutant due to its long lifetime in the atmosphere. Its hemispheric transport patterns and eventual deposition are therefore of major concern. For the purpose of global atmospheric mercury chemistry and transport modelling the ECHMERIT model was developed. ECHMERIT, based on the global circulation model ECHAM5 differs from most global mercury models in that the emissions, chemistry (including general tropospheric chemistry and mercury chemistry), transport and deposition are coupled on-line to the GCM. The chemistry mechanism includes an online calculation of photolysis rate constants using the Fast-J photolysis mechanism, the CBM-Z tropospheric gas-phase mechanism and aqueous-phase chemistry based on the MECCA mechanism. Additionally, a mercury chemistry mechanism that incorporates gas and aqueous phase mercury chemistry is included. A detailed description of the model, including the wet and dry deposition modules, and the implemented emissions is given in this technical report. First model testing and evaluation show a satisfactory model performance for surface ozone and mercury concentrations (with a mean bias of 1.46 ppb for ozone and a mean bias of 13.55 ppq for TGM when compared with EMEP station data). Requirements regarding measurement data and emission inventories which could considerably improve model skill are discussed.
APA, Harvard, Vancouver, ISO, and other styles
8

Jung, G., I. M. Hedgecock, and N. Pirrone. "ECHMERIT V1.0 – a new global fully coupled mercury-chemistry and transport model." Geoscientific Model Development 2, no. 2 (November 4, 2009): 175–95. http://dx.doi.org/10.5194/gmd-2-175-2009.

Full text
Abstract:
Abstract. Mercury is a global pollutant due to its long lifetime in the atmosphere. Its hemispheric transport patterns and eventual deposition are therefore of major concern. For the purpose of global atmospheric mercury chemistry and transport modelling the ECHMERIT model was developed. ECHMERIT, based on the global circulation model ECHAM5 differs from most global mercury models in that the emissions, chemistry (including general tropospheric chemistry and mercury chemistry), transport and deposition are coupled on-line to the GCM. The chemistry mechanism includes an online calculation of photolysis rate constants using the Fast-J photolysis mechanism, the CBM-Z tropospheric gas-phase mechanism and aqueous-phase chemistry based on the MECCA mechanism. Additionally, a mercury chemistry mechanism that incorporates gas and aqueous phase mercury chemistry is included. A detailed description of the model, including the wet and dry deposition modules, and the implemented emissions is given in this technical report. First model testing and evaluation show a satisfactory model performance for surface ozone and mercury mixing ratios (with a mean bias of 1.46 nmol/mol for ozone and a mean bias of 13.55 fmol/mol for TGM when compared with EMEP station data). Requirements regarding measurement data and emission inventories which could considerably improve model skill are discussed.
APA, Harvard, Vancouver, ISO, and other styles
9

Riede, H., P. Jöckel, and R. Sander. "Quantifying atmospheric transport, chemistry, and mixing using a new trajectory-box model and a global atmospheric-chemistry GCM." Geoscientific Model Development Discussions 2, no. 1 (May 8, 2009): 455–84. http://dx.doi.org/10.5194/gmdd-2-455-2009.

Full text
Abstract:
Abstract. We present a novel method for the quantification of transport, chemistry, and mixing along atmospheric trajectories based on a consistent model hierarchy. The hierarchy consists of the new atmospheric-chemistry trajectory-box model CAABA/MJT and the three-dimensional (3-D) global ECHAM/MESSy atmospheric-chemistry (EMAC) general circulation model (GCM). CAABA/MJT employs the atmospheric box model CAABA together with the atmospheric-chemistry submodel MECCA (M), the photochemistry submodel JVAL (J), and the new trajectory submodel TRAJECT (T), to simulate atmospheric chemistry along atmospheric trajectories which are provided offline. With the same submodels coupled to the EMAC model, a unique consistency is achieved, which allows to separate contributions of transport, chemistry, and mixing along the trajectory pathways through comparison of results from the two models. Consistency of transport between the trajectory-box model CAABA/MJT and the 3-D EMAC model is achieved via calculation of trajectories based on 3-D wind fields from EMAC. The procedure to obtain the necessary statistical basis for the quantification analysis is described as well as the comprehensive diagnostics with respect to chemistry. The quantification method is applied to 3-D model data as a diagnostic tool with the focus on the transfer of results to observational data.
APA, Harvard, Vancouver, ISO, and other styles
10

Wang, ChangJian, Jennifer Wen, ShouXiang Lu, and Jin Guo. "Single-step chemistry model and transport coefficient model for hydrogen combustion." Science China Technological Sciences 55, no. 8 (June 29, 2012): 2163–68. http://dx.doi.org/10.1007/s11431-012-4932-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Chemistry and transport model"

1

Al-Mudaris, A. A. M. "Ionic transport in model polymer electrolytes." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235984.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Monks, Sarah Anne. "A model study of chemistry and transport in the Arctic troposphere." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/2286/.

Full text
Abstract:
In this thesis the TOMCAT chemical transport model is used to investigate the processes which control the concentrations of CO and O3 in the Arctic troposphere. Particular focus is on understanding the main sources of CO, O3 and NOy species in the Arctic, distinguishing between natural and anthropogenic sources and the current drivers of interannual variability (IAV). First results from a new version of TOMCAT, with extended hydrocarbon chemistry and heterogeneous uptake of N2O5, shows better agreement with observed CO from MOPITT, surface stations and aircraft. Changes in simulated burdens demonstrate the importance of NMHC as a source of CO, O3 and PAN in the troposphere and show that the complexity of chemical schemes may have contributed to previously reported inter-model differences. The high PAN sensitivity to additional NMHC is particularly important in the Arctic as it is the dominant source of NOx in the Arctic lower troposphere, producing up to 30% of total O3 in the summer. This thesis contains the first source contribution analysis to consider impacts of fire emissions throughout the year in comparison to anthropogenic sources. Anthropogenic emissions are found to be the largest source of Arctic CO (48%), followed by methane (25%) and fires (13%). In summer, fire and anthropogenic sources contribute equally to the total CO burden. Boreal fires are the dominant source of O3 and NOx compared to anthropogenic emissions. North America contributes the largest amount (30%) to the total anthropogenic CO burden, followed by East Asia (26%), Europe (23%) and South Asia (9%). In contrast, North America makes the largest contribution (9%) to the Arctic O3 burden, followed by Europe (7%) and then Asia (6%). Overall, CO shows that the Arctic is most sensitive to emissions changes in Europe, then North America and then Asia. Fire emissions are the dominant driver of current Arctic CO IAV, causing 84-93% of observed variability. A statistically significant correlation is found between observed CO and the El Nino 3.4 index due to a link with fires. El Nino is strongly associated with increased fire emissions in regions of North, Central and South America, Africa, and Asia. In contrast, El Nino is associated with reduced fire emissions in eastern North America, Europe, southern Asia and Australia. The temperature dependence of fires in several regions indicates that fire activity will increase in a warmer climate.
APA, Harvard, Vancouver, ISO, and other styles
3

Sim, Alec. "Unified model of charge transport in insulating polymeric materials." Thesis, Utah State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3606878.

Full text
Abstract:

Presented here is a detailed study of electron transport in highly disordered insulating materials (HDIM). Since HDIMs do not lend themselves to a lattice construct, the question arises: How can we describe their electron transport behavior in a consistent theoretical framework? In this work, a large group of experiments, theories, and physical models are coalesced into a single formalism to better address this difficult question. We find that a simple set of macroscopic transport equations--cast in a new formalism--provides an excellent framework in which to consider a wide array of experimentally observed behaviors. It is shown that carrier transport in HDIMs is governed by the transport equations that relate the density of localized states (DOS) within the band gap and the occupation of these states through thermal and quantum interactions. The discussion is facilitated by considering a small set of simple DOS models. This microscopic picture gives rise to a clear understanding of the macroscopic carrier transport in HDIMs. We conclude with a discussion of the application of this theoretical formalism to four specific types of experimental measurements employed by the Utah State University space environments effects Materials Physics Group.

APA, Harvard, Vancouver, ISO, and other styles
4

Klasen, Dagmar. "Variational assimilation of stratospheric remote sounding data by an adjoint chemistry-transport-model." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969576269.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Crone, Gilia Cornelia. "Parallel Lagrangian models for turbulent transport and chemistry." [S.l.] : Utrecht : [s.n.] ; Universiteitsbibliotheek Utrecht [Host], 1997. http://www.ubu.ruu.nl/cgi-bin/grsn2url?01763357.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Follows, Michael John. "A statistical-dynamical climate model to trace gas transport and chemistry in the troposphere." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278041.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Schrödner, Roland. "Modeling the tropospheric multiphase aerosol-cloud processing using the 3-D chemistry transport model COSMO-MUSCAT." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-199294.

Full text
Abstract:
Die chemische Zusammensetzung und die physikalischen Eigenschaften von troposphärischen Gasen, Partikeln und Wolken hängen aufgrund zahlreicher Prozesse stark voneinander ab. Insbesondere chemische Multiphasenprozesse in Wolken können die physiko-chemischen Eigenschaften der Luft und troposphärischer Partikel klein- und großräumig verändern. Diese chemische Prozessierung des troposphärischen Aerosols innerhalb von Wolken beeinflusst die chemischen Umwandlungen in der Atmosphäre, die Bildung von Wolken, deren Ausdehnung und Lebensdauer, sowie die Transmissivität von einfallender und ausgehender Strahlung durch die Atmosphäre. Damit sind wolken-chemische Prozesse relevant für das Klima auf der Erde und für verschiedene Umweltaspekte. Daher ist ein umfassendes Verständnis dieser Prozesse wichtig. Die explizite Behandlung chemischer Reaktionen in der Flüssigphase stellt allerdings eine Herausforderung für atmosphärische Computermodelle dar. Detaillierte Beschreibungen der Flüssigphasenchemie werden deshalb häufig nur für Boxmodelle verwendet. Regionale Chemie-Transport-Modelle und Klimamodelle berücksichtigen diese Prozesse meist nur mit vereinfachten chemischen Mechanismen oder Parametrisierungen. Die vorliegende Arbeit hat zum Ziel, den Einfluss der chemischer Mehrphasenprozesse innerhalb von Wolken auf den Verbleib relevanter Spurengase und Partikelbestandteile mit Hilfe des state‑of‑the‑art 3D-Chemie-Transport-Modells COSMO-MUSCAT zu untersuchen. Zu diesem Zweck wurde das Model um eine detaillierte Beschreibung chemischer Prozesse in der Flüssigphase erweitert. Zusätzlich wurde das bestehende Depositionsschema verbessert, um auch die Deposition von Nebeltropfen zu berücksichtigen. Die durchgeführten Modellerweiterungen ermöglichen eine bessere Beschreibung des troposphärischen Multiphasensystems. Das erweiterte Modellsystem wurde sowohl für künstliche 2D-Bergüberströmungsszenarien als auch für reale 3D-Simulationen angewendet. Mittels Prozess- und Sensitivitätsstudien wurde der Einfluss (i) des Detailgrades der verwendeten Mechanismen zur Beschreibung der Flüssigphasenchemie, (ii) der Größenauflösung des Tropfenspektrums und (iii) der Tropfenanzahl auf die chemischen Modellergebnisse untersucht. Die Studien belegen, dass die Auswirkungen der Wolkenchemie aufgrund ihres signifikanten Einflusses auf die Oxidationskapazität in der Gas- und Flüssigphase, die Bildung von organischer und anorganischer Partikelmasse sowie die Azidität der Wolkentropfen und Partikel in regionalen Chemie-Transport-Modellen berücksichtigt werden sollten. Im Vergleich zu einer vereinfachten Beschreibung der Wolkenchemie führt die Verwendung des detaillierten chemischen Flüssigphasenmechanismus C3.0RED zu verringerten Konzentrationen wichtiger Oxidantien in der Gasphase, einer höheren Nitratmasse in der Nacht, geringeren nächtlichen pH-Werten und einer veränderten Sulfatbildung. Darüber hinaus ermöglicht eine detaillierte Wolkenchemie erst Untersuchungen zur Bildung sekundärer organischer Partikelmasse in der Flüssigphase. Die größenaufgelöste Behandlung der Flüssigphasenchemie hatte nur geringen Einfluss auf die chemischen Modellergebnisse. Schließlich wurde das erweiterte Modell für Fallstudien zur Feldmesskampagne HCCT‑2010 genutzt. Zum ersten Mal wurde dabei ein chemischer Mechanismus mit der Komplexität von C3.0RED verwendet. Die räumlichen Effekte realer Wolken z. B. auf troposphärische Oxidantien oder die Bildung anorganischer Masse wurden untersucht. Der Vergleich der Modellergebnisse mit verfügbaren Messungen hat viele Übereinstimmungen aber auch interessante Unterschiede aufgezeigt, die weiter untersucht werden müssen
In the troposphere, a vast number of interactions between gases, particles, and clouds affect their physico-chemical properties, which, therefore, highly depend on each other. Particularly, multiphase chemical processes within clouds can alter the physico-chemical properties of the gas and the particle phase from the local to the global scale. This cloud processing of the tropospheric aerosol may, therefore, affect chemical conversions in the atmosphere, the formation, extent, and lifetime of clouds, as well as the interaction of particles and clouds with incoming and outgoing radiation. Considering the relevance of these processes for Earth\'s climate and many environmental issues, a detailed understanding of the chemical processes within clouds is important. However, the treatment of aqueous phase chemical reactions in numerical models in a comprehensive and explicit manner is challenging. Therefore, detailed descriptions of aqueous chemistry are only available in box models, whereas regional chemistry transport and climate models usually treat cloud chemical processes by means of rather simplified chemical mechanisms or parameterizations. The present work aims at characterizing the influence of chemical cloud processing of the tropospheric aerosol on the fate of relevant gaseous and particulate aerosol constituents using the state-of-the-art 3‑D chemistry transport model (CTM) COSMO‑MUSCAT. For this purpose, the model was enhanced by a detailed description of aqueous phase chemical processes. In addition, the deposition schemes were improved in order to account for the deposition of cloud droplets of ground layer clouds and fogs. The conducted model enhancements provide a better insight in the tropospheric multiphase system. The extended model system was applied for an artificial mountain streaming scenario as well as for real 3‑D case studies. Process and sensitivity studies were conducted investigating the influence of (i) the detail of the used aqueous phase chemical representation, (ii) the size-resolution of the cloud droplets, and (iii) the total droplet number on the chemical model output. The studies indicated the requirement to consider chemical cloud effects in regional CTMs because of their key impacts on e.g., oxidation capacity in the gas and aqueous phase, formation of organic and inorganic particulate mass, and droplet acidity. In comparison to rather simplified aqueous phase chemical mechanisms focusing on sulfate formation, the use of the detailed aqueous phase chemistry mechanism C3.0RED leads to decreased gas phase oxidant concentrations, increased nighttime nitrate mass, decreased nighttime pH, and differences in sulfate mass. Moreover, the treatment of detailed aqueous phase chemistry enables the investigation of the formation of aqueous secondary organic aerosol mass. The consideration of size-resolved aqueous phase chemistry shows only slight effects on the chemical model output. Finally, the enhanced model was applied for case studies connected to the field experiment HCCT-2010. For the first time, an aqueous phase mechanism with the complexity of C3.0RED was applied in 3‑D chemistry transport simulations. Interesting spatial effects of real clouds on e.g., tropospheric oxidants and inorganic mass have been studied. The comparison of the model output with available measurements revealed many agreements and also interesting disagreements, which need further investigations
APA, Harvard, Vancouver, ISO, and other styles
8

Janardhanan, Vinod. "A detailed approach to model transport, heterogeneous chemistry, and electrochemistry in solid-oxide fuel cells." Karlsruhe : Univ.-Verl. Karlsruhe, 2007. http://d-nb.info/986289124/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Labrador, Lorenzo. "Sensitivity of tropospheric chemistry to the source of NOx from lightning simulations with the global 3D chemistry transport model MATCH-MPIC /." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97690277X.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Ibikunle, Olatunde Idris. "Modelling Chlorine Transport in Temperate Soils." Thesis, Linköping University, Department of Water and Environmental Studies, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9524.

Full text
Abstract:

Microbes have been suggested to have a strong impact on the transportation of chlorine in soils. There are speculations about environmental factors limiting microbial effect on chlorine movement and retention. For this study, a numerical hydrochemical model was built to describe microbial transformation of chlorine in a laboratory lysimeter experiment. Undisturbed soil cores used to set-up the experiment were collected from a coniferous forest soil in southeast Sweden. The lysimeters were modelled in groups depending on their different water and chloride treatments. Microbial transformation of chlorine was better described under high water residence times and high chloride loads compared to low water residence times and low chloride loads. Microbial activity was also shown to properly account for a sudden shift from net-chlorine retention to net chlorine release in most of the lysimeters. Oxygen proved to be very important in accounting for the short-term shift from chloride retention to release in all the lysimeters. Model outcome revealed that 0.02– 0.10 mg Cl- could be available per day in a coniferous soil depending on season and other soil conditions. This study shows that modeling enable a better understanding of chlorine biogeochemistry. It also confirms the speculated importance of microbial activities on chloride availability in soils.

APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Chemistry and transport model"

1

Runkel, Robert L. One-Dimensional Transport with Equilibrium Chemistry (OTEQ): A reactive transport model for streams and rivers. Reston, Va: U.S. Department of the Interior, U.S. Geological Survey, 2010.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Yung, Y. L. Chemistry and transport in a multi-dimensional model: Annual performance report for NAGW-413. [Washington, DC: National Aeronautics and Space Administration, 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Myers, Tommy E. Application of a semianalytical model to TNT transport in laboratory soil columns. Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1998.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

D, Reible Danny, ed. Diffusion models of environmental transport. Boca Raton, Fla: Lewis Publishers, 2000.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Janardhanan, Vinod. A detailed approach to model transport, heterogeneous chemistry, and electrochemistry in solid-oxide fuel cells. Karlsruhe: Universita tsverlag, 2007.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Follows, Michael John. A statistical-dynamical climate model applied to trace gas transport and chemistry in the Troposphere. Norwich: University of East Anglia, 1990.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

O, Manning James, and United States. National Aeronautics and Space Administration., eds. A study of carbon monoxide distribution determinations for a global transport model. [Washington, DC: National Aeronautics and Space Administration, 1987.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Clark, Mark M. Transport modeling for environmental engineers and scientists. 2nd ed. Hoboken, N.J: Wiley, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Transport modeling for environmental engineers and scientists. 2nd ed. Hoboken, N.J: Wiley, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Clark, Mark M. Transport modeling for environmental engineers and scientists. 2nd ed. Hoboken, N.J: Wiley, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Chemistry and transport model"

1

Bieser, Johannes, and Martin Otto Paul Ramacher. "Multi-compartment Chemistry Transport Models." In Springer Proceedings in Complexity, 119–23. Berlin, Heidelberg: Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-63760-9_18.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Müller, Andreas. "Parallelization of a mesoscale atmospheric transport-chemistry model." In High-Performance Computing and Networking, 200–206. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/3-540-61142-8_548.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Tung, K. K. "A Coupled Model of Zonally Averaged Dynamics, Radiation and Chemistry." In Transport Processes in the Middle Atmosphere, 183–98. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3973-8_13.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Joly, Mathieu, Béatrice Josse, Matthieu Plu, Joaquim Arteta, Jonathan Guth, and Frédérik Meleux. "High-Resolution Air Quality Forecasts with MOCAGE Chemistry Transport Model." In Springer Proceedings in Complexity, 563–65. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-24478-5_91.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Venkatram, Akula, Shuming Du, Ramamurthy Hariharan, William Carter, and Robert Goldstein. "The Separation of Transport and Chemistry in a Photochemical Model." In Air Pollution Modeling and Its Application XII, 459–66. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-9128-0_47.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Michou, M., F. Brocheton, A. Dufour, and V. H. Peuch. "Surface Exchanges in the Multiscale Chemistry and Transport Model MOCAGE." In Air Pollution Modelling and Simulation, 578–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04956-3_60.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Alvarado, Matthew J., Kelley C. Barsanti, Serena H. Chung, Daniel A. Jaffe, and Charles T. Moore. "Smoke Chemistry." In Wildland Fire Smoke in the United States, 167–98. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-87045-4_6.

Full text
Abstract:
AbstractSmoke chemistry (i.e., chemical transformations taking place within smoke plumes) can alter the composition and toxicity of smoke on time scales from minutes to days. Air quality agencies need better information on and better models of smoke chemistry to more accurately characterize the contributions of smoke to ambient ozone and particulate matter, and to better predict good windows for prescribed burning. The ability of these agencies to quantify the contributions of wildland fires to air pollutants and the ability of forest and burn managers to both predict and mitigate these impacts are limited by how current models represent smoke chemistry. This limitation is interconnected with uncertainties in smoke emissions, plume dynamics, and long-range transport. Improving predictive models will require a combination of laboratory, field, and modeling studies focused on enhancing our knowledge of smoke chemistry, including when smoke interacts with anthropogenic emissions and enters indoors.
APA, Harvard, Vancouver, ISO, and other styles
8

Elbern, H., H. Schmidt, and A. Ebel. "Parallel 4D-Variational Data Assimilation for an Eulerian Chemistry Transport Model." In Large Scale Computations in Air Pollution Modelling, 151–60. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4570-1_12.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Olaguer, Eduardo P. "An Efficient 3-D Model for Global Circulation, Transport and Chemistry." In The IMA Volumes in Mathematics and its Applications, 205–76. New York, NY: Springer New York, 2002. http://dx.doi.org/10.1007/978-1-4757-3474-4_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Botchev, Mike, István Faragó, and Ágnes Havasi. "Testing Weighted Splitting Schemes on a One-Column Transport-Chemistry Model." In Large-Scale Scientific Computing, 295–302. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-24588-9_33.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Chemistry and transport model"

1

Dasgupta, Debolina, Wenting Sun, Marc Day, Andy Aspden, and Tim C. Lieuwen. "Transport model effects on turbulence-chemistry interactions in lean premixed flames." In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-0447.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Vermael, Stefaan, Herbert De Vleeschouwer, Kristiaan Neyts, Artur Adamski, and Goran Stojmenovik. "Detailed comparison of several ion-transport algorithms in a 1-dimensional liquid crystal model." In XIV Conference on Liquid Crystals, Chemistry, Physics, and Applications, edited by Jolanta Rutkowska, Stanislaw J. Klosowicz, and Jerzy Zielinski. SPIE, 2002. http://dx.doi.org/10.1117/12.472153.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Maltsev, Alexander, Amsini Sadiki, and Johannes Janicka. "Numerical Prediction of Partially Premixed Flames Based on Extended BML Model Coupled With Mixing Transport and ILDM Chemical Model." In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38265.

Full text
Abstract:
To improve the numerical prediction of partially premixed flames occurring in gas turbine combustors the extension of the well-known Bray-Moss-Libby model for premixed combustion is presented. The model modification based on the algebraic closure for a mean chemical source term is coupled to the mixing transport model providing variable equivalence ratio distinguishing partially premixed flames. Finite rate chemistry is incorporated by means of ILDM model solving transport equations for two reaction progress variables conditioned on the flame front. Multivariate presumed PDF model is used for the turbulence chemistry interaction treatment. Turbulence models of two levels of complexity are applied in order to investigate the influence of non-gradient turbulent transport phenomenon. Redistribution terms in second moment transport equations are extended to take into account strongly variable density effects. Model combinations considered are assessed simulating piloted partially premixed flame. The obtained results agree well with experimental data.
APA, Harvard, Vancouver, ISO, and other styles
4

Penenko, Alexey, Vladimir Penenko, Roman Nuterman, Alexander Baklanov, and Alexander Mahura. "Direct variational data assimilation algorithm for atmospheric chemistry data with transport and transformation model." In XXI International Symposium Atmospheric and Ocean Optics. Atmospheric Physics, edited by Oleg A. Romanovskii. SPIE, 2015. http://dx.doi.org/10.1117/12.2206008.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Gupta, Ankur, Jiang Zhu, M. S. Anand, and Ruud Eggels. "A flame-generated-manifold chemistry based transport PDF model for gas-turbine combustor simulations." In 52nd Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-1028.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Goldin, Graham M., Jens Madsen, Douglas L. Straub, William A. Rogers, and Kent H. Casleton. "Detailed Chemistry Simulations of a Trapped Vortex Combustor." In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38780.

Full text
Abstract:
Steady simulations of a Trapped Vortex Combustor are performed with the Strained Laminar Flamelet model, the Eddy Dissipation Concept (EDC) model and the Composition PDF Transport model using an accurate 19 species Augmented Reduced Mechanism. CO predictions are reasonable, although the EDC model over-predicts CO since the reaction time in the fine scales is less than the residence time in the combustor. The PDF Transport model over-predicts NO by a factor of four for reasons that are not well understood at present. In-situ Adaptive Tabulation (ISAT) accelerates chemistry calculations by two to three orders of magnitude, making 3D CFD calculations with detailed chemistry computationally feasible.
APA, Harvard, Vancouver, ISO, and other styles
7

Wang, Yanqing, Zhe Liu, Xiang Li, Shiqian Xu, and Jun Lu. "Seawater Breakthrough Monitoring and Reservoir-Model Improvement Using Natural Boron." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204306-ms.

Full text
Abstract:
Abstract Natural geochemical data, which refer to the natural ion concentration in produced water, contain important reservoir information, but is seldomly exploited. Some ions were used as conservative tracers to obtain better knowledge of reservoir. However, using only conservative ions can limit the application of geochemical data as most ions are nonconservative and can either interact with formation rock or react with other ions. Besides, mistakenly using nonconservative ion as being conservative may cause unexpected results. In order to further explore the nonconservative natural geochemical information, the interaction between ion and rock matrix is integrated into the reservoir simulator to describe the nonconservative ion transport in porous media. Boron, which is a promising nonconservative ion, is used to demonstrate the application of nonconservative ion. Based on the new model, the boron concentration data together with water production rate and oil production rate are assimilated through ensemble smoother multiple data assimilation (ES-MDA) algorithm to improve the reservoir model. Results indicate that including nonconservative ion data in the history matching process not only yield additional improvement in permeability field, but also can predict the distribution of clay content, which can promote the accuracy of using boron data to determine injection water breakthrough percentage. However, mistakenly regarding nonconservative ion being conservative in the history matching workflow can deteriorate the accuracy of reservoir model.
APA, Harvard, Vancouver, ISO, and other styles
8

Zhang, Ronglei, Xiaolong Yin, Yu-Shu Wu, and Philip H. Winterfeld. "A Fully Coupled Model of Nonisothermal Multiphase Flow, Solute Transport and Reactive Chemistry in Porous Media." In SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 2012. http://dx.doi.org/10.2118/159380-ms.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Penenko, Alexey V., Pavel N. Antokhin, and Anastasia A. Grishina. "Variational data assimilation of airborne sensing profiles to the transport and transformation model of atmospheric chemistry." In XXIII International Symposium, Atmospheric and Ocean Optics, Atmospheric Physics, edited by Oleg A. Romanovskii. SPIE, 2017. http://dx.doi.org/10.1117/12.2288830.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Kapoor, Abhinav, Ashoke De, and Rakesh Yadav. "Multi Eulerian PDF Transport Modelling of Turbulent Swirling Flame." In ASME 2012 Gas Turbine India Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gtindia2012-9543.

Full text
Abstract:
The paper presents numerical investigation using Multi environmental Eulerian PDF (MEPDF) transport model for turbulence-chemistry interaction. A turbulent flame (SM1) from Sydney swirling burner database is simulated along with two isothermal cases (N29S054, N16S159) of different swirl numbers. MEPDF methodology, a probability density function (PDF) transport modeling, exploits the advantages of the PDF transport equation and is also computationally less expensive compared to popularly used Lagrangian solution approach of PDF transport equation. In the MEPDF approach, the PDF transport equation is represented by direct quadrature method of moments with presumed shape PDF and the closure of micro-mixing is achieved by interaction by exchange with mean (IEM) model. In the current work, the reacting flow results using MEPDF are reported for SM1 flame, which is a part of the database of turbulent reacting flows and widely considered as benchmark test cases for validating turbulent-chemistry interaction models. Initially, the non-reacting flows are simulated to properly choose the boundary conditions, turbulence models as well as the grid; followed by reacting flow calculations. SKE and RKE predictions show good agreement with each other while the other turbulence model exhibit substantially different behavior, especially for non-reacting case. However, RKE model exhibits substantial improvement in the case of reacting flows.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Chemistry and transport model"

1

Atherton, C. S. Predicting tropospheric ozone and hydroxyl radical in a global, three-dimensional, chemistry, transport, and deposition model. Office of Scientific and Technical Information (OSTI), January 1995. http://dx.doi.org/10.2172/130611.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

MacKinnon, R. J., T. M. Sullivan, and R. R. Kinsey. BLT-EC (Breach, Leach and Transport-Equilibrium Chemistry) data input guide. A computer model for simulating release and coupled geochemical transport of contaminants from a subsurface disposal facility. Office of Scientific and Technical Information (OSTI), May 1997. http://dx.doi.org/10.2172/491476.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

LeGrand, Sandra, Christopher Polashenski, Theodore Letcher, Glenn Creighton, Steven Peckham, and Jeffrey Cetola. The AFWA dust emission scheme for the GOCART aerosol model in WRF-Chem v3.8.1. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41560.

Full text
Abstract:
Airborne particles of mineral dust play a key role in Earth’s climate system and affect human activities around the globe. The numerical weather modeling community has undertaken considerable efforts to accurately forecast these dust emissions. Here, for the first time in the literature, we thoroughly describe and document the Air Force Weather Agency (AFWA) dust emission scheme for the Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) aerosol model within the Weather Research and Forecasting model with chemistry (WRF-Chem) and compare it to the other dust emission schemes available in WRF-Chem. The AFWA dust emission scheme addresses some shortcomings experienced by the earlier GOCART-WRF scheme. Improved model physics are designed to better handle emission of fine dust particles by representing saltation bombardment. WRF-Chem model performance with the AFWA scheme is evaluated against observations of dust emission in southwest Asia and compared to emissions predicted by the other schemes built into the WRF-Chem GOCART model. Results highlight the relative strengths of the available schemes, indicate the reasons for disagreement, and demonstrate the need for improved soil source data.
APA, Harvard, Vancouver, ISO, and other styles
4

MacKinnon, R. J., T. M. Sullivan, S. A. Simonson, and C. J. Suen. BLT-EC (Breach, Leach Transport, and Equilibrium Chemistry), a finite-element model for assessing the release of radionuclides from low-level waste disposal units: Background, theory, and model description. Office of Scientific and Technical Information (OSTI), August 1995. http://dx.doi.org/10.2172/108216.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Schutt, Timothy, and Manoj Shukla. Predicting the impact of aqueous ions on fate and transport of munition compounds. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41481.

Full text
Abstract:
A model framework for natural water has been developed using computational chemistry techniques to elucidate the interactions between solvated munition compounds and eight common ions in naturally occurring water sources. The interaction energies, residence times, coordination statistics, and surface preferences of nine munition related compounds with each ion were evaluated. The propensity of these interactions to increase degradation of the munition compound was predicted using accelerated replica QM/MM simulations. The degradation prediction data qualitatively align with previous quantum mechanical studies. The results suggest that primary ions of interest for fate and transport modeling of munition compounds in natural waters may follow the relative importance of SO₄²⁻, Cl⁻ ≫ HCO₃⁻, Na⁺, Mg²⁺ > Ca²⁺, K⁺, and NH₄⁺.
APA, Harvard, Vancouver, ISO, and other styles
6

Michaels, Michelle, Theodore Letcher, Sandra LeGrand, Nicholas Webb, and Justin Putnam. Implementation of an albedo-based drag partition into the WRF-Chem v4.1 AFWA dust emission module. Engineer Research and Development Center (U.S.), January 2021. http://dx.doi.org/10.21079/11681/42782.

Full text
Abstract:
Employing numerical prediction models can be a powerful tool for forecasting air quality and visibility hazards related to dust events. However, these numerical models are sensitive to surface conditions. Roughness features (e.g., rocks, vegetation, furrows, etc.) that shelter or attenuate wind flow over the soil surface affect the magnitude and spatial distribution of dust emission. To aide in simulating the emission phase of dust transport, we used a previously published albedo-based drag partition parameterization to better represent the component of wind friction speed affecting the immediate soil sur-face. This report serves as a guide for integrating this parameterization into the Weather Research and Forecasting with Chemistry (WRF-Chem) model. We include the procedure for preprocessing the required input data, as well as the code modifications for the Air Force Weather Agency (AFWA) dust emission module. In addition, we provide an example demonstration of output data from a simulation of a dust event that occurred in the Southwestern United States, which incorporates use of the drag partition.
APA, Harvard, Vancouver, ISO, and other styles
7

Dudley, Lynn M., Uri Shani, and Moshe Shenker. Modeling Plant Response to Deficit Irrigation with Saline Water: Separating the Effects of Water and Salt Stress in the Root Uptake Function. United States Department of Agriculture, March 2003. http://dx.doi.org/10.32747/2003.7586468.bard.

Full text
Abstract:
Standard salinity management theory, derived from blending thermodynamic and semi- empirical considerations leads to an erroneous perception regarding compensative interaction among salinity stress factors. The current approach treats matric and osmotic components of soil water potential separately and then combines their effects to compute overall response. With deficit water a severe yield decrease is expected under high salinity, yet little or no reduction is predicted for excess irrigation, irrespective of salinity level. Similarly, considerations of competition between chloride and nitrate ions have lead to compensation hypothesis and to application of excess nitrate under saline conditions. The premise of compensative interaction of growth factors behind present practices (that an increase in water application alleviates salinity stress) may result in collateral environmental damage. Over-irrigation resulting in salinization and elevated ground water threatens productivity on a global scale. Other repercussions include excessive application of nitrate to compensate for salinity, unwillingness to practice deficit irrigation with saline water, and under-utilization of marginal water. The objectives for the project were as follows: 1) To develop a database for model parameterization and validation by studying yield and transpiration response to water availability, excessive salinity and salt composition. 2) To modify the root sink terms of an existing mechanism-based model(s) of water flow, transpiration, crop yield, salt transport, and salt chemistry. 3) To develop conceptual and quantitative models of ion uptake that considers the soil solution concentration and composition. 4) To develop a conceptual and quantitative models of effects of NaCl and boron accumulation on yield and transpiration. 5) To add a user interface to the water flow, transpiration, crop yield, salt transport, chemistry model to make it easy for others to use. We conducted experiments in field plots and lysimeters to study biomass production and transpiration of com (Zeamays cv. Jubilee), melon (Cucumismelo subsp. melo cv. Galia), tomato (Lycopersiconesculentum Mill. cv. 5656), onion (Alliumcepa L. cv. HA 944), and date palms (Phoenix Dactylifera L. cv. Medjool) under salinity combined with water or with nitrate (growth promoters) or with boron (growth inhibitor). All factors ranged from levels not limiting to plant function to severe inhibition. For cases of combined salinity with water stress, or excess boron, we observed neither additive nor compensative effects on plant yield and transpiration. In fact, yield and transpiration at each combination of the various factors were primarily controlled by one of them, the most limiting factor to plant activity. We proposed a crop production model of the form Yr = min{gi(xi), where Yr = Yi ym-1 is relative yield,Ym is the maximum yield obtained in each experiment, Xi is an environmental factor, gi is a piecewise-linear response function, Yi is yield of a particular treatment. We selected a piecewise-linear approach because it highlights the irrigation level where the response to one factor ceases and a second factor begins. The production functions generate response "envelopes" containing possible yields with diagonal lines represent response to Xi alone and the lines parallel to the X-axis represent response to salinity alone. A multiplicative model was also derived approximating the limiting behaviour for incorporation in a hydrochemical model. The multiplicative model was selected because the response function was required to be continuous. The hydrochemical model was a better predictor of field-measured water content and salt profiles than models based on an additive and compensative model of crop response to salinity and water stress.
APA, Harvard, Vancouver, ISO, and other styles
8

Montville, Thomas J., and Roni Shapira. Molecular Engineering of Pediocin A to Establish Structure/Function Relationships for Mechanistic Control of Foodborne Pathogens. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568088.bard.

Full text
Abstract:
This project relates the structure of the bacteriocin molecule (which is genetically determined) to its antimicrobial function. We have sequenced the 19,542 bp pediocin plasmid pMD136 and developed a genetic transfer system for pediococci. The pediocin A operon is complex, containing putative structural, immunity, processing, and transport genes. The deduced sequence of the pediocin A molecule contains 44 amino acids and has a predicted PI of 9.45. Mechanistic studies compared the interaction of pediocin PA-1 and nisin with Listeria monocytgenes cells and model lipid systems. While significant nisin-induced intracellular ATP depletion is caused by efflux, pediocin-induced depletion is caused exclusively by hydrolysis. Liposomes derived from L. monocytogenes phospholipids were used to study the physical chemistry of pediocin and nisin interactions with lipids. Their different pH optima are the results of different specific ionizable amino acids. We generated a predicted 3-D structural model for pediocin PA-1 and used a variety of mutant pediocins to demonstrate that the "positive patch" at residues 11 and 12 (and not the YGNGV consensus sequence) is responsible for the binding step of pediocin action. This structure/function understanding gained here provides necessary prerequisites to the more efficacious use of bacteriocins to control foodborne pathogens.
APA, Harvard, Vancouver, ISO, and other styles
9

William Goddard, Mario Blanco, Lawrence Cathles, Paul Manhardt, Peter Meulbroek, and Yongchun Tang. Advanced Chemistry Basins Model. Office of Scientific and Technical Information (OSTI), November 2002. http://dx.doi.org/10.2172/901422.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Blanco, Mario, Lawrence Cathles, Paul Manhardt, Peter Meulbroek, and Yongchun Tang. Advanced Chemistry Basins Model. Office of Scientific and Technical Information (OSTI), February 2003. http://dx.doi.org/10.2172/807772.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Chemistry and transport model' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography