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Sample records for chem chem phys

  1. Comment on ``On the Crooks fluctuation theorem and the Jarzynski equality'' [J. Chem. Phys. 129, 091101 (2008)

    Science.gov (United States)

    Adib, Artur B.

    2009-06-01

    It has recently been argued that a self-consistency condition involving the Jarzynski equality (JE) and the Crooks fluctuation theorem (CFT) is violated for a simple Brownian process [L. Y. Chen, J. Chem. Phys.129, 091101 (2008)]. This note adopts the definitions in the original formulation of the JE and CFT and demonstrates the contrary.

  2. Chem systems

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that world styrene demand, paced by a near doubling of combined requirements in East Asia and Oceania, could reach 19.3 million metric tons by 2000, an average growth rate of 3.7%/year. So concludes Chem Systems Inc., Tarrytown, N.Y., in a study of world styrene markets through the end of the century. Pacific Rim styrene production and consumption throughout the 1990s are predicted to make up increasingly larger shares of world markets, while demand and production lag in the U.S. and western Europe. Demand and capacity in other parts of the world will grow in real terms, increasing combined market shares only slightly. Most of the increase will be driven by demand in East Asia and Oceania, where consumption by century's end is expected to increase 4.48 million metric tons from 2.25 million tons in 1991. Meantime, Japan's styrene demand in 2000 is projected at 2.64 million tons, a 500,000 ton increase from 1991 demand but a net market loss of 1.9%

  3. iNR-PhysChem: a sequence-based predictor for identifying nuclear receptors and their subfamilies via physical-chemical property matrix.

    Directory of Open Access Journals (Sweden)

    Xuan Xiao

    Full Text Available Nuclear receptors (NRs form a family of ligand-activated transcription factors that regulate a wide variety of biological processes, such as homeostasis, reproduction, development, and metabolism. Human genome contains 48 genes encoding NRs. These receptors have become one of the most important targets for therapeutic drug development. According to their different action mechanisms or functions, NRs have been classified into seven subfamilies. With the avalanche of protein sequences generated in the postgenomic age, we are facing the following challenging problems. Given an uncharacterized protein sequence, how can we identify whether it is a nuclear receptor? If it is, what subfamily it belongs to? To address these problems, we developed a predictor called iNR-PhysChem in which the protein samples were expressed by a novel mode of pseudo amino acid composition (PseAAC whose components were derived from a physical-chemical matrix via a series of auto-covariance and cross-covariance transformations. It was observed that the overall success rate achieved by iNR-PhysChem was over 98% in identifying NRs or non-NRs, and over 92% in identifying NRs among the following seven subfamilies: NR1--thyroid hormone like, NR2--HNF4-like, NR3--estrogen like, NR4--nerve growth factor IB-like, NR5--fushi tarazu-F1 like, NR6--germ cell nuclear factor like, and NR0--knirps like. These rates were derived by the jackknife tests on a stringent benchmark dataset in which none of protein sequences included has ≥60% pairwise sequence identity to any other in a same subset. As a user-friendly web-server, iNR-PhysChem is freely accessible to the public at either http://www.jci-bioinfo.cn/iNR-PhysChem or http://icpr.jci.edu.cn/bioinfo/iNR-PhysChem. Also a step-by-step guide is provided on how to use the web-server to get the desired results without the need to follow the complicated mathematics involved in developing the predictor. It is anticipated that iNR-PhysChem may

  4. ChemIDplus

    Data.gov (United States)

    U.S. Department of Health & Human Services — Chemical database is a dictionary of over 400,000 chemicals (names, synonyms, and structures). ChemIDplus includes links to NLM and other databases and resources,...

  5. ChemSearch Journal: Submissions

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... SCOPE: ChemSearch Journal is a peer-reviewed journal that publishes ... Authors whose papers have been accepted for publication will be notified in writing. ... The literature cited must be discussed to show the relationships between the ...

  6. ChemSpell Web Service API

    Data.gov (United States)

    U.S. Department of Health & Human Services — The ChemSpell Web Service API provides chemical name spell checking and chemical name synonym look-up. ChemSpell contains more than 1.3 million chemical names...

  7. PubChem atom environments.

    Science.gov (United States)

    Hähnke, Volker D; Bolton, Evan E; Bryant, Stephen H

    2015-01-01

    Atom environments and fragments find wide-spread use in chemical information and cheminformatics. They are the basis of prediction models, an integral part in similarity searching, and employed in structure search techniques. Most of these methods were developed and evaluated on the relatively small sets of chemical structures available at the time. An analysis of fragment distributions representative of most known chemical structures was published in the 1970s using the Chemical Abstracts Service data system. More recently, advances in automated synthesis of chemicals allow millions of chemicals to be synthesized by a single organization. In addition, open chemical databases are readily available containing tens of millions of chemical structures from a multitude of data sources, including chemical vendors, patents, and the scientific literature, making it possible for scientists to readily access most known chemical structures. With this availability of information, one can now address interesting questions, such as: what chemical fragments are known today? How do these fragments compare to earlier studies? How unique are chemical fragments found in chemical structures? For our analysis, after hydrogen suppression, atoms were characterized by atomic number, formal charge, implicit hydrogen count, explicit degree (number of neighbors), valence (bond order sum), and aromaticity. Bonds were differentiated as single, double, triple or aromatic bonds. Atom environments were created in a circular manner focused on a central atom with radii from 0 (atom types) up to 3 (representative of ECFP_6 fragments). In total, combining atom types and atom environments that include up to three spheres of nearest neighbors, our investigation identified 28,462,319 unique fragments in the 46 million structures found in the PubChem Compound database as of January 2013. We could identify several factors inflating the number of environments involving transition metals, with many

  8. Corrigendum to "A novel downscaling technique for the linkage of global and regional air quality modeling" published in Atmos. Chem. Phys., 9, 9169–9185, 2009

    Directory of Open Access Journals (Sweden)

    Y. F. Lam

    2010-04-01

    Full Text Available Recently, downscaling global atmospheric model outputs (GCTM for the USEPA Community Multiscale Air Quality (CMAQ Initial (IC and Boundary Conditions (BC have become practical because of the rapid growth of computational technologies that allow global simulations to be completed within a reasonable time. The traditional method of generating IC/BC by profile data has lost its advocates due to the weakness of the limited horizontal and vertical variations found on the gridded boundary layers. Theoretically, high quality GCTM IC/BC should yield a better result in CMAQ. Unfortunately, several researchers have found that the outputs from GCTM IC/BC are not necessarily better than profile IC/BC due to the excessive transport of O3 aloft in GCTM IC/BC. In this paper, we intend to investigate the effects of using profile IC/BC and global atmospheric model data. In addition, we are suggesting a novel approach to resolve the existing issue in downscaling.

    In the study, we utilized the GEOS-Chem model outputs to generate time-varied and layer-varied IC/BC for year 2002 with the implementation of tropopause determining algorithm in the downscaling process (i.e., based on chemical (O3 tropopause definition. The comparison between the implemented tropopause approach and the profile IC/BC approach is performed to demonstrate improvement of considering tropopause. It is observed that without using tropopause information in the downscaling process, unrealistic O3 concentrations are created at the upper layers of IC/BC. This phenomenon has caused over-prediction of surface O3 in CMAQ. In addition, the amount of over-prediction is greatly affected by temperature and latitudinal location of the study domain. With the implementation of the algorithm, we have successfully resolved the incompatibility issues in the vertical layer structure between global and regional chemistry models to yield better surface O3

  9. The ChemChar process

    International Nuclear Information System (INIS)

    Manahan, S.E.; Kinner, L.L.; Larsen, D.W.

    1992-01-01

    This paper reports on reverse-burn gasification is a thermochemical process that offers a number of advantages over conventional incineration for the treatment of a variety of waste materials. Patented as the ChemChar Process, reverse-burn gasification can treat wastes in the forms of solids, liquids, sludges, and soils. Waste constituents are destroyed by conversion to a combustible gas and to a dry, inert, carbonaceous solid which is either non-hazardous or can be readily mixed with cement to prevent leaching of the radioactive, toxic, or heavy metal constituents that are retained in the char residue or ash. In this way, reverse-burn gasification can be a very effective method for treating organic waste sludges containing heavy metals and mixed wastes consisting of hazardous chemicals contaminated with radioactive substances. As with any gasification waste treatment process, reverse-burn gasification offers inherent advantages in the areas of destruction efficiency and emissions control. This is because, instead of an exhaust gas that must treated to control emissions, gasification produces a combustible gas that is burned. Trace levels of contaminants are destroyed in burning the gas, and a catalyst may be employed, if necessary

  10. PubChem Power User Gateway (PUG)

    Data.gov (United States)

    U.S. Department of Health & Human Services — PUG provides access to PubChem services via a programmatic interface. Users may download data, initiate chemical structure searches, standardize chemical structures...

  11. Exploiting PubChem for Virtual Screening.

    Science.gov (United States)

    Xie, Xiang-Qun

    2010-12-01

    IMPORTANCE OF THE FIELD: PubChem is a public molecular information repository, a scientific showcase of the NIH Roadmap Initiative. The PubChem database holds over 27 million records of unique chemical structures of compounds (CID) derived from nearly 70 million substance depositions (SID), and contains more than 449,000 bioassay records with over thousands of in vitro biochemical and cell-based screening bioassays established, with targeting more than 7000 proteins and genes linking to over 1.8 million of substances. AREAS COVERED IN THIS REVIEW: This review builds on recent PubChem-related computational chemistry research reported by other authors while providing readers with an overview of the PubChem database, focusing on its increasing role in cheminformatics, virtual screening and toxicity prediction modeling. WHAT THE READER WILL GAIN: These publicly available datasets in PubChem provide great opportunities for scientists to perform cheminformatics and virtual screening research for computer-aided drug design. However, the high volume and complexity of the datasets, in particular the bioassay-associated false positives/negatives and highly imbalanced datasets in PubChem, also creates major challenges. Several approaches regarding the modeling of PubChem datasets and development of virtual screening models for bioactivity and toxicity predictions are also reviewed. TAKE HOME MESSAGE: Novel data-mining cheminformatics tools and virtual screening algorithms are being developed and used to retrieve, annotate and analyze the large-scale and highly complex PubChem biological screening data for drug design.

  12. DuraChem trademark - challenges and solutions

    International Nuclear Information System (INIS)

    Howard, I.S.; Bowan, B.W.; Kirshe, M.H.

    1996-01-01

    Vitrification of low-level ion exchange resins represents numerous challenges never before successfully accomplished. These challenges include (1) Feed material preparation and transfer, (2) Melter temperature and volume control, (3) Glass composition, stabilization, and control, and (4) Off-gas treatment and particulate capture. The DuraChem trademark team of Chem-Nuclear Systems, Inc. and GTS Duratek, Inc. began its journey in 1994 and is in the process of starting-up the first centralized vitrification facility for commercial ion-exchange and filtration media. This paper addresses each of the challenges and provides an update of this unique volume-reduction and stabilization technology

  13. Literature information in PubChem: associations between PubChem records and scientific articles.

    Science.gov (United States)

    Kim, Sunghwan; Thiessen, Paul A; Cheng, Tiejun; Yu, Bo; Shoemaker, Benjamin A; Wang, Jiyao; Bolton, Evan E; Wang, Yanli; Bryant, Stephen H

    2016-01-01

    PubChem is an open archive consisting of a set of three primary public databases (BioAssay, Compound, and Substance). It contains information on a broad range of chemical entities, including small molecules, lipids, carbohydrates, and (chemically modified) amino acid and nucleic acid sequences (including siRNA and miRNA). Currently (as of Nov. 2015), PubChem contains more than 150 million depositor-provided chemical substance descriptions, 60 million unique chemical structures, and 225 million biological activity test results provided from over 1 million biological assay records. Many PubChem records (substances, compounds, and assays) include depositor-provided cross-references to scientific articles in PubMed. Some PubChem contributors provide bioactivity data extracted from scientific articles. Literature-derived bioactivity data complement high-throughput screening (HTS) data from the concluded NIH Molecular Libraries Program and other HTS projects. Some journals provide PubChem with information on chemicals that appear in their newly published articles, enabling concurrent publication of scientific articles in journals and associated data in public databases. In addition, PubChem links records to PubMed articles indexed with the Medical Subject Heading (MeSH) controlled vocabulary thesaurus. Literature information, both provided by depositors and derived from MeSH annotations, can be accessed using PubChem's web interfaces, enabling users to explore information available in literature related to PubChem records beyond typical web search results. Graphical abstractLiterature information for PubChem records is derived from various sources.

  14. "CHEM"opera for Chemistry Education

    Science.gov (United States)

    Chung, Yong Hee

    2013-01-01

    "CHEM"opera is an opera blended with demonstrations of chemical reactions. It has been produced and performed twice by chemistry undergraduate students at Hallym University in South Korea. It aims to demonstrate interesting chemical reactions to chemistry students, children and the public and to facilitate their understanding of the role…

  15. The PubChem chemical structure sketcher

    Directory of Open Access Journals (Sweden)

    Ihlenfeldt Wolf D

    2009-12-01

    Full Text Available Abstract PubChem is an important public, Web-based information source for chemical and bioactivity information. In order to provide convenient structure search methods on compounds stored in this database, one mandatory component is a Web-based drawing tool for interactive sketching of chemical query structures. Web-enabled chemical structure sketchers are not new, being in existence for years; however, solutions available rely on complex technology like Java applets or platform-dependent plug-ins. Due to general policy and support incident rate considerations, Java-based or platform-specific sketchers cannot be deployed as a part of public NCBI Web services. Our solution: a chemical structure sketching tool based exclusively on CGI server processing, client-side JavaScript functions, and image sequence streaming. The PubChem structure editor does not require the presence of any specific runtime support libraries or browser configurations on the client. It is completely platform-independent and verified to work on all major Web browsers, including older ones without support for Web2.0 JavaScript objects.

  16. I:\\AA-TYPESET\\CHEM\\2005\\Van Es.vp

    African Journals Online (AJOL)

    NJD

    aDepartment of Biochemistry and Microbiology, Cook College, Rutgers The State University of New Jersey, 08903-0231, USA. .... 4 formation is expected to transfer to the more basic nitrogen of ...... Jouannetaud, French Patent (2000). Chem.

  17. ChemPreview: an augmented reality-based molecular interface.

    Science.gov (United States)

    Zheng, Min; Waller, Mark P

    2017-05-01

    Human computer interfaces make computational science more comprehensible and impactful. Complex 3D structures such as proteins or DNA are magnified by digital representations and displayed on two-dimensional monitors. Augmented reality has recently opened another door to access the virtual three-dimensional world. Herein, we present an augmented reality application called ChemPreview with the potential to manipulate bio-molecular structures at an atomistic level. ChemPreview is available at https://github.com/wallerlab/chem-preview/releases, and is built on top of the Meta 1 platform https://www.metavision.com/. ChemPreview can be used to interact with a protein in an intuitive way using natural hand gestures, thereby making it appealing to computational chemists or structural biologists. The ability to manipulate atoms in real world could eventually provide new and more efficient ways of extracting structural knowledge, or designing new molecules in silico. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. 3D-e-Chem-VM: Structural Cheminformatics Research Infrastructure in a Freely Available Virtual Machine

    NARCIS (Netherlands)

    McGuire, R.; Verhoeven, S.; Vass, M.; Vriend, G.; Esch, I.J. de; Lusher, S.J.; Leurs, R.; Ridder, L.; Kooistra, A.J.; Ritschel, T.; Graaf, C. de

    2017-01-01

    3D-e-Chem-VM is an open source, freely available Virtual Machine ( http://3d-e-chem.github.io/3D-e-Chem-VM/ ) that integrates cheminformatics and bioinformatics tools for the analysis of protein-ligand interaction data. 3D-e-Chem-VM consists of software libraries, and database and workflow tools

  19. 3D-e-Chem-VM : Structural Cheminformatics Research Infrastructure in a Freely Available Virtual Machine

    NARCIS (Netherlands)

    McGuire, Ross; Verhoeven, Stefan; Vass, Márton; Vriend, Gerrit; De Esch, Iwan J P; Lusher, Scott J.; Leurs, Rob; Ridder, Lars; Kooistra, Albert J.; Ritschel, Tina; de Graaf, C.

    2017-01-01

    3D-e-Chem-VM is an open source, freely available Virtual Machine ( http://3d-e-chem.github.io/3D-e-Chem-VM/ ) that integrates cheminformatics and bioinformatics tools for the analysis of protein-ligand interaction data. 3D-e-Chem-VM consists of software libraries, and database and workflow tools

  20. AutoClickChem: click chemistry in silico.

    Directory of Open Access Journals (Sweden)

    Jacob D Durrant

    Full Text Available Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

  1. AutoClickChem: click chemistry in silico.

    Science.gov (United States)

    Durrant, Jacob D; McCammon, J Andrew

    2012-01-01

    Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

  2. FastChem: An ultra-fast equilibrium chemistry

    Science.gov (United States)

    Kitzmann, Daniel; Stock, Joachim

    2018-04-01

    FastChem is an equilibrium chemistry code that calculates the chemical composition of the gas phase for given temperatures and pressures. Written in C++, it is based on a semi-analytic approach, and is optimized for extremely fast and accurate calculations.

  3. ChemAND - a system health monitor for plant chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C.W.; Mitchel, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Dundar, Y.; Bergeron, M.; Laporte, R. [Hydro-Quebec, Groupe Chimie, Centrale Nucleaire Gentilly-2, Gentilly, Quebec (Canada)

    2001-03-01

    Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam-cycle system as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

  4. ChemAND - a system health monitor for plant chemistry

    International Nuclear Information System (INIS)

    Turner, C.W.; Mitchell, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M.; Dundar, Y.; Bergeron, M.; Laporte, R.

    2001-01-01

    Effective management of plant systems throughout their lifetime requires much more than data acquisition and display-it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

  5. ChemAND - a system health monitor for plant chemistry

    International Nuclear Information System (INIS)

    Turner, C.W.; Mitchel, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M.; Dundar, Y.; Bergeron, M.; Laporte, R.

    2001-03-01

    Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam-cycle system as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

  6. ChemCalc: a building block for tomorrow's chemical infrastructure.

    Science.gov (United States)

    Patiny, Luc; Borel, Alain

    2013-05-24

    Web services, as an aspect of cloud computing, are becoming an important part of the general IT infrastructure, and scientific computing is no exception to this trend. We propose a simple approach to develop chemical Web services, through which servers could expose the essential data manipulation functionality that students and researchers need for chemical calculations. These services return their results as JSON (JavaScript Object Notation) objects, which facilitates their use for Web applications. The ChemCalc project http://www.chemcalc.org demonstrates this approach: we present three Web services related with mass spectrometry, namely isotopic distribution simulation, peptide fragmentation simulation, and molecular formula determination. We also developed a complete Web application based on these three Web services, taking advantage of modern HTML5 and JavaScript libraries (ChemDoodle and jQuery).

  7. Comb-e-Chem: an e-science research project

    OpenAIRE

    Frey, Jeremy G.

    2003-01-01

    The background to the Comb-e-Chem e-Science pilot project funded under the UK -Science Programme is presented and the areas being addresses within chemistry and more specifically combinatorial chemistry are disucssed. The ways in which the ideas underlying the application of computer technology can improve the production, analysis and dissemination of chemical information and knowledge in a collaborative environment are discussed.

  8. Automation and semantics: the CombeChem experience

    OpenAIRE

    Frey, Jeremy G.

    2004-01-01

    Some of the experiences of the CombeChem e-Science project in relation to both automation and the need for semantics in combining modern computer science techniques and chemistry are discussed. In particular the aspects of the smart laboratory, large scale data handling and the way this impacts on the necessary database technology are discussed. In addition some of the ways in which the grid can enable greater user interaction with services such as the National Crystallography Service and imp...

  9. Early Warning: Brought to you by the DoD Chem-Bio Defense Program

    Science.gov (United States)

    Security Robots Lasers RSS Feed Early Warning: Brought to you by the DoD Chem-Bio Defense Program help warfighters prevent, protect against, respond to or recover from chem-bio threats and effects . Hassell said he and his team don't monitor the world for chem-bio threats, they develop the tools that

  10. Engaging Organic Chemistry Students Using ChemDraw for iPad

    Science.gov (United States)

    Morsch, Layne A.; Lewis, Michael

    2015-01-01

    Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows…

  11. ChemANDTM - a system health monitor for plant chemistry

    International Nuclear Information System (INIS)

    Turner, C.W.; Mitchel, G.R.; Balakrishnan, P.V.; Tosello, G.

    1999-07-01

    Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation and feeds these parameters to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently has two analytical models developed for the balance-of-plant. CHEMSOLV calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information will be used by operations personnel to evaluate the potential for SG tube corrosion in the crevice region. CHEMSOLV also calculates chemistry conditions throughout the steam-cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. A second model, SLUDGE, calculates the deposit loading in the SG as a function of time, based on concentrations of corrosion product in the final feedwater and plant operating conditions. Operations personnel can use this information to predict where to inspect and when to clean. In a future development, SLUDGE will track deposit loading arising from start-up crud bursts and will be used in conjunction with the thermohydraulics code, THIRST, to predict

  12. ChemProt: A disease chemical biology database

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Oprea, Tudor I.

    2013-01-01

    The integration of chemistry, biology, and informatics to study drug actions across multiple biological targets, pathways, and biological systems is an emerging paradigm in drug discovery. Rather than reducing a complex system to simplistic models, fields such as chemogenomics and translational...... informatics are seeking to build a holistic model for a better understanding of the drug pharmacology and clinical effects. Here we will present a webserver called ChemProt that can assist, in silico, the drug actions in the context of cellular and disease networks and contribute in the field of disease...... chemical biology, drug repurposing, and off-target effects prediction....

  13. WRF-Chem Model Simulations of Arizona Dust Storms

    Science.gov (United States)

    Mohebbi, A.; Chang, H. I.; Hondula, D.

    2017-12-01

    The online Weather Research and Forecasting model with coupled chemistry module (WRF-Chem) is applied to simulate the transport, deposition and emission of the dust aerosols in an intense dust outbreak event that took place on July 5th, 2011 over Arizona. Goddard Chemistry Aerosol Radiation and Transport (GOCART), Air Force Weather Agency (AFWA), and University of Cologne (UoC) parameterization schemes for dust emission were evaluated. The model was found to simulate well the synoptic meteorological conditions also widely documented in previous studies. The chemistry module performance in reproducing the atmospheric desert dust load was evaluated using the horizontal field of the Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectro (MODIS) radiometer Terra/Aqua and Aerosol Robotic Network (AERONET) satellites employing standard Dark Target (DT) and Deep Blue (DB) algorithms. To assess the temporal variability of the dust storm, Particulate Matter mass concentration data (PM10 and PM2.5) from Arizona Department of Environmental Quality (AZDEQ) ground-based air quality stations were used. The promising performance of WRF-Chem indicate that the model is capable of simulating the right timing and loading of a dust event in the planetary-boundary-layer (PBL) which can be used to forecast approaching severe dust events and to communicate an effective early warning.

  14. Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

    Science.gov (United States)

    Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

    2017-12-01

    Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

  15. ChemProt: a disease chemical biology database

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Nielsen, Sonny Kim; Audouze, Karine Marie Laure

    2011-01-01

    Systems pharmacology is an emergent area that studies drug action across multiple scales of complexity, from molecular and cellular to tissue and organism levels. There is a critical need to develop network-based approaches to integrate the growing body of chemical biology knowledge with network...... biology. Here, we report ChemProt, a disease chemical biology database, which is based on a compilation of multiple chemical-protein annotation resources, as well as disease-associated protein-protein interactions (PPIs). We assembled more than 700 000 unique chemicals with biological annotation for 30...... evaluation of environmental chemicals, natural products and approved drugs, as well as the selection of new compounds based on their activity profile against most known biological targets, including those related to adverse drug events. Results from the disease chemical biology database associate citalopram...

  16. Operational forecast products and applications based on WRF/Chem

    Science.gov (United States)

    Hirtl, Marcus; Flandorfer, Claudia; Langer, Matthias; Mantovani, Simone; Olefs, Marc; Schellander-Gorgas, Theresa

    2015-04-01

    The responsibilities of the national weather service of Austria (ZAMG) include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. The ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. The mother domain expands over Europe, North Africa and parts of Russia. The nested domain includes the alpine region and has a horizontal resolution of 4 km. Local emissions (Austria) are used in combination with European inventories (TNO and EMEP) for the simulations. The modeling system is presented and the results from the evaluation of the assimilation of pollutants using the 3D-VAR software GSI is shown. Currently observational data (PM10 and O3) from the Austrian Air-Quality network and from European stations (EEA) are assimilated into the model on an operational basis. In addition PM maps are produced using Aerosol Optical Thickness (AOT) observations from MODIS in combination with model data using machine learning techniques. The modeling system is operationally evaluated with different data sets. The emphasis of the application is on the forecast of pollutants which are compared to the hourly values (PM10, O3 and NO2) of the Austrian Air-Quality network. As the meteorological conditions are important for transport and chemical processes, some parameters like wind and precipitation are automatically evaluated (SAL diagrams, maps, …) with other models (e.g. ECMWF, AROME, …) and ground stations via web interface. The prediction of the AOT is also important for operators of solar power plants. In the past Numerical Weather Prediction (NWP) models were used to predict the AOT based on cloud forecasts at the ZAMG. These models do not consider the spatial and temporal variation of the aerosol distribution in the atmosphere with a consequent impact on the accuracy of forecasts especially during clear-sky days

  17. ChemProt-2.0: visual navigation in a disease chemical biology database

    DEFF Research Database (Denmark)

    Kjærulff, Sonny Kim; Wich, Louis; Kringelum, Jens Vindahl

    2013-01-01

    ChemProt-2.0 (http://www.cbs.dtu.dk/services/ChemProt-2.0) is a public available compilation of multiple chemical-protein annotation resources integrated with diseases and clinical outcomes information. The database has been updated to > 1.15 million compounds with 5.32 millions bioactivity measu...

  18. ChemProt-3.0: a global chemical biology diseases mapping

    DEFF Research Database (Denmark)

    Kringelum, Jens Vindahl; Kjærulff, Sonny Kim; Brunak, Søren

    2016-01-01

    ChemProt is a publicly available compilation of chemical-protein-disease annotation resources that enables the study of systems pharmacology for a small molecule across multiple layers of complexity from molecular to clinical levels. In this third version, ChemProt has been updated to more than 1...

  19. The ChemChar process for hazardous-waste treatment

    International Nuclear Information System (INIS)

    McGowin, A.E.

    1991-01-01

    The ChemChar Reverse-Burn Gasification Process has been studied for application to the thermal destruction of radioactive waste organic ion exchange resins. The resulting char was mixed with cement to form a dry, leach-resistant final disposal product. Successful regeneration of spent granular activated carbons was achieved with reverse-burn gasification. Regeneration parameters such as moisture content and supplemental fuel addition were investigated. The performance of regenerated carbon was evaluated by batch equilibrium and breakthrough assay and was comparable to that of the original. Surface areas were determined by the BET method. The fate of mercury during reverse-burn gasification was investigated. TRB Char adsorbent was used to remove mercury vapor emission from the process. The use of petroleum coke as a substrate for gasification of wastes was studied. Petroleum coke was activated by reverse-burn gasification to produce a highly porous, low surface area solid. Destruction efficiency for hexachlorobenzene on activated coke was considerably lower than on coal char, however, the addition of iron appeared to catalyze hexachlorobenzene gasification

  20. Searching Online Chemical Data Repositories via the ChemAgora Portal.

    Science.gov (United States)

    Zanzi, Antonella; Wittwehr, Clemens

    2017-12-26

    ChemAgora, a web application designed and developed in the context of the "Data Infrastructure for Chemical Safety Assessment" (diXa) project, provides search capabilities to chemical data from resources available online, enabling users to cross-reference their search results with both regulatory chemical information and public chemical databases. ChemAgora, through an on-the-fly search, informs whether a chemical is known or not in each of the external data sources and provides clikable links leading to the third-party web site pages containing the information. The original purpose of the ChemAgora application was to correlate studies stored in the diXa data warehouse with available chemical data. Since the end of the diXa project, ChemAgora has evolved into an independent portal, currently accessible directly through the ChemAgora home page, with improved search capabilities of online data sources.

  1. Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7.

    Directory of Open Access Journals (Sweden)

    Cédric de Poorter

    Full Text Available Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.

  2. Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7.

    Science.gov (United States)

    de Poorter, Cédric; Baertsoen, Kevin; Lannoy, Vincent; Parmentier, Marc; Springael, Jean-Yves

    2013-01-01

    Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.

  3. NutriChem 2.0: exploring the effect of plant-based foods on human health and drug efficacy

    DEFF Research Database (Denmark)

    Ni, Yueqiong; Jensen, Kasper; Kouskoumvekaki, Eirini

    2017-01-01

    NutriChem is a database generated by text mining of 21 million MEDLINE abstracts that links plant-based foods with their small molecule components and human health effect. In this new, second release of NutriChem (NutriChem 2.0) we have integrated information on overlapping protein targets between...

  4. Interactive Gaussian Graphical Models for Discovering Depth Trends in ChemCam Data

    Science.gov (United States)

    Oyen, D. A.; Komurlu, C.; Lanza, N. L.

    2018-04-01

    Interactive Gaussian graphical models discover surface compositional features on rocks in ChemCam targets. Our approach visualizes shot-to-shot relationships among LIBS observations, and identifies the wavelengths involved in the trend.

  5. CASSINI S MIMI CHEMS SENSOR CALIBRATED DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass Spectrometer (CHEMS) contains a deflection system and an overall field of view of 159 x 4 deg....

  6. Identifying Known Unknowns Using the USEPA CompTox Chemistry Dashboard AnalytBioanlytChem Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — In this research, the performance of the Dashboard for identifying “known unknowns” was evaluated against that of the online ChemSpider database, one of the primary...

  7. New developments on ChemCam laser transmitter and potential applications for other planetology programs

    Science.gov (United States)

    Faure, Benoît; Durand, Eric; Maurice, Sylvestre; Bruneau, Didier; Montmessin, Franck

    2017-11-01

    ChemCam is a LIBS Instrument mounted on the MSL 2011 NASA mission. The laser transmitter of this Instrument has been developed by the French society Thales Optronique (former Thales Laser) with a strong technical support from CNES. The paper will first rapidly present the performance of this laser and will then describe the postChemCam developments realized on and around this laser for new planetology programs.

  8. radEq Add-On Module for CFD Solver Loci-CHEM

    Science.gov (United States)

    McCloud, Peter

    2013-01-01

    Loci-CHEM to be applied to flow velocities where surface radiation due to heating from compression and friction becomes significant. The module adds a radiation equilibrium boundary condition to the computational fluid dynamics (CFD) code to produce accurate results. The module expanded the upper limit for accurate CFD solutions of Loci-CHEM from Mach 4 to Mach 10 based on Space Shuttle Orbiter Re-Entry trajectories. Loci-CHEM already has a very promising architecture and performance, but absence of radiation equilibrium boundary condition limited the application of Loci-CHEM to below Mach 4. The immediate advantage of the add-on module is that it allows Loci-CHEM to work with supersonic flows up to Mach 10. This transformed Loci-CHEM from a rocket engine- heritage CFD code with general subsonic and low-supersonic applications, to an aeroheating code with hypersonic applications. The follow-on advantage of the module is that it is a building block for additional add-on modules that will solve for the heating generated at Mach numbers higher than 10.

  9. ChemSession'09 - 6. Warsaw Seminar of the PhD Students in Chemistry - Abstracts; ChemSession'09 - 6. Warszawskie Seminarium Doktorantow Chemikow - Streszczenia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Book of Abstracts contains short descriptions of presentations 3 lectures and 105 posters presented during ChemSession'09 - 6{sup th} Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found.

  10. ChemSession'08 - 5. Warsaw Seminar of the PhD Students in Chemistry - Abstracts; ChemSession'08 - 5. Warszawskie Seminarium Doktorantow Chemikow - Streszczenia

    Energy Technology Data Exchange (ETDEWEB)

    Madura, I [ed.

    2008-07-01

    Book of Abstracts consists of short descriptions of presentations: 5 lectures and 127 posters presented during ChemSession'08 - 5{sup th} Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found.

  11. Distributed chemical computing using ChemStar: an open source java remote method invocation architecture applied to large scale molecular data from PubChem.

    Science.gov (United States)

    Karthikeyan, M; Krishnan, S; Pandey, Anil Kumar; Bender, Andreas; Tropsha, Alexander

    2008-04-01

    We present the application of a Java remote method invocation (RMI) based open source architecture to distributed chemical computing. This architecture was previously employed for distributed data harvesting of chemical information from the Internet via the Google application programming interface (API; ChemXtreme). Due to its open source character and its flexibility, the underlying server/client framework can be quickly adopted to virtually every computational task that can be parallelized. Here, we present the server/client communication framework as well as an application to distributed computing of chemical properties on a large scale (currently the size of PubChem; about 18 million compounds), using both the Marvin toolkit as well as the open source JOELib package. As an application, for this set of compounds, the agreement of log P and TPSA between the packages was compared. Outliers were found to be mostly non-druglike compounds and differences could usually be explained by differences in the underlying algorithms. ChemStar is the first open source distributed chemical computing environment built on Java RMI, which is also easily adaptable to user demands due to its "plug-in architecture". The complete source codes as well as calculated properties along with links to PubChem resources are available on the Internet via a graphical user interface at http://moltable.ncl.res.in/chemstar/.

  12. The Another Assimilation System for WRF-Chem (AAS4WRF): a new mass-conserving emissions pre-processor for WRF-Chem regional modelling

    Science.gov (United States)

    Vara Vela, A. L.; Muñoz, A.; Lomas, A., Sr.; González, C. M.; Calderon, M. G.; Andrade, M. D. F.

    2017-12-01

    The Weather Research and Forecasting with Chemistry (WRF-Chem) community model have been widely used for the study of pollutants transport, formation of secondary pollutants, as well as for the assessment of air quality policies implementation. A key factor to improve the WRF-Chem air quality simulations over urban areas is the representation of anthropogenic emission sources. There are several tools that are available to assist users in creating their own emissions based on global emissions information (e.g. anthro_emiss, prep_chem_src); however, there is no single tool that will construct local emissions input datasets for any particular domain at this time. Because the official emissions pre-processor (emiss_v03) is designed to work with domains located over North America, this work presents the Another Assimilation System for WRF-Chem (AAS4WRF), a ncl based mass-conserving emissions pre-processor designed to create WRF-Chem ready emissions files from local inventories on a lat/lon projection. AAS4WRF is appropriate to scale emission rates from both surface and elevated sources, providing the users an alternative way to assimilate their emissions to WRF-Chem. Since it was successfully tested for the first time for the city of Lima, Peru in 2014 (managed by SENAMHI, the National Weather Service of the country), several studies on air quality modelling have applied this utility to convert their emissions to those required for WRF-Chem. Two case studies performed in the metropolitan areas of Sao Paulo and Manizales in Brazil and Colombia, respectively, are here presented in order to analyse the influence of using local or global emission inventories in the representation of regulated air pollutants such as O3 and PM2.5. Although AAS4WRF works with local emissions information at the moment, further work is being conducted to make it compatible with global/regional emissions data file format. The tool is freely available upon request to the corresponding author.

  13. 3D-e-Chem-VM: Structural Cheminformatics Research Infrastructure in a Freely Available Virtual Machine.

    Science.gov (United States)

    McGuire, Ross; Verhoeven, Stefan; Vass, Márton; Vriend, Gerrit; de Esch, Iwan J P; Lusher, Scott J; Leurs, Rob; Ridder, Lars; Kooistra, Albert J; Ritschel, Tina; de Graaf, Chris

    2017-02-27

    3D-e-Chem-VM is an open source, freely available Virtual Machine ( http://3d-e-chem.github.io/3D-e-Chem-VM/ ) that integrates cheminformatics and bioinformatics tools for the analysis of protein-ligand interaction data. 3D-e-Chem-VM consists of software libraries, and database and workflow tools that can analyze and combine small molecule and protein structural information in a graphical programming environment. New chemical and biological data analytics tools and workflows have been developed for the efficient exploitation of structural and pharmacological protein-ligand interaction data from proteomewide databases (e.g., ChEMBLdb and PDB), as well as customized information systems focused on, e.g., G protein-coupled receptors (GPCRdb) and protein kinases (KLIFS). The integrated structural cheminformatics research infrastructure compiled in the 3D-e-Chem-VM enables the design of new approaches in virtual ligand screening (Chemdb4VS), ligand-based metabolism prediction (SyGMa), and structure-based protein binding site comparison and bioisosteric replacement for ligand design (KRIPOdb).

  14. Soil Diversity and Hydration as Observed by ChemCam at Gale Crater, Mars

    Science.gov (United States)

    Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schröder, S.; Cousin, A.; Berger, G.; Clegg, S. M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R. C.; Fabre, C.; Goetz, W.; Bish, D.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, R.; Rampe, E.; McConnochie, T. H.; Pinet, P.; Blaney, D.; Léveillé, R.; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J. G.; Bridges, N.; Clark, B. C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M. D.; Fisk, M.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M. B.; Melikechi, N.; Mezzacappa, A.; Mischna, M. A.; Moores, J. E.; Newsom, H.; Ollila, A.; Perez, R.; Renno, N.; Sirven, J.-B.; Tokar, R.; de la Torre, M.; d'Uston, L.; Vaniman, D.; Yingst, A.; Kemppinen, Osku; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Mauchien, Patrick; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Schieber, Juergen; Geffroy, Claude; Baratoux, David; Cros, Alain; Lee, Qiu-Mei; Pallier, Etienne; Parot, Yann; Toplis, Mike; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Robert, François; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Fassett, Caleb; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Nolan, Thomas; Radziemski, Leon; Berman, Daniel; Dobrea, Eldar Noe; Williams, Rebecca M. E.; Lewis, Kevin; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey

    2013-09-01

    The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

  15. ChemTS: an efficient python library for de novo molecular generation

    Science.gov (United States)

    Yang, Xiufeng; Zhang, Jinzhe; Yoshizoe, Kazuki; Terayama, Kei; Tsuda, Koji

    2017-12-01

    Automatic design of organic materials requires black-box optimization in a vast chemical space. In conventional molecular design algorithms, a molecule is built as a combination of predetermined fragments. Recently, deep neural network models such as variational autoencoders and recurrent neural networks (RNNs) are shown to be effective in de novo design of molecules without any predetermined fragments. This paper presents a novel Python library ChemTS that explores the chemical space by combining Monte Carlo tree search and an RNN. In a benchmarking problem of optimizing the octanol-water partition coefficient and synthesizability, our algorithm showed superior efficiency in finding high-scoring molecules. ChemTS is available at https://github.com/tsudalab/ChemTS.

  16. Soil diversity and hydration as observed by ChemCam at Gale crater, Mars

    Science.gov (United States)

    Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schroder, S.; Cousin, A.; Berger, G.; Clegg, S.M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R.C.; Fabre, C.; Goetz, W.; Bish, D.L.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, Ryan Bradley; Rampe, E.; McConnochie, T.H.; Pinet, P.; Blaney, D.; ,; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J.G.; Bridges, N.; Clark, B. C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M.D.; Fisk, M. R.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M.B.; Melikechi, N.; Mezzacappa, Alissa; Mischna, M.A.; Moores, J.E.; Newsom, H.; Ollila, A.; ,; Renno, N.; Sirven, J.B.; Tokar, R.; de la Torre, M.; d'Uston, L.; Vaniman, D.; Yingst, A.

    2013-01-01

    The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

  17. ChemCam on MSL 2009: first laser induced breakdown spectrometer for space science

    Energy Technology Data Exchange (ETDEWEB)

    Wiens, Roger C [Los Alamos National Laboratory

    2008-01-01

    ChemCam is one of the 10 instrument suites on the Mars Science Laboratory, a martian rover being built by Jet Propulsion Laboratory, for the next NASA mission to Mars (MSL 2009). ChemCam is an instrument package consisting of two remote sensing instruments: a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS provides elemental compositions of rocks and soils, while the RMI places the LIBS analyses in their geomorphologic context. Both instruments rely on an autofocus capability to precisely focus on the chosen target, located at distances from the rover comprised between 1 and 9 m for LIBS, and 2 m and infinity for RMI. ChemCam will help determine which samples, within the vicinity of the MSL rover, are of sufficient interest to use the contact and in-situ instruments for further characterization. It will provide valuable analyses of samples that are inaccessible to contact and in-situ instruments, and of a much larger number of samples than can be done with this kind of instrument. ChemCam also has a capability to provide passive spectroscopy data of rocks and soils on Mars. ChemCam hardware consists of a Mast Unit (MU), provided by France, and a Body Unit (BU) built and tested in the USA. The Flight Model of the MU is assembled, tested and now available in the USA, while the BU is currently being assembled and tested. Both will be connected by the end of year '08 for end-to-end functional and performance tests, before delivery to JPL and assembly on the MSL rover. Launch is scheduled for October 09. After describing the concept of ChemCam, this presentation focuses on its French part, Mast Unit. The results presented show that Mast Unit is able to generate a plasma and collect its light, over the full applicable ranges of distances and temperatures on Mars.

  18. ChemProt-3.0: a global chemical biology diseases mapping

    DEFF Research Database (Denmark)

    Kringelum, Jens Vindahl; Kjærulff, Sonny Kim; Brunak, Søren

    2016-01-01

    ChemProt is a publicly available compilation of chemical-protein-disease annotation resources that enables the study of systems pharmacology for a small molecule across multiple layers of complexity from molecular to clinical levels. In this third version, ChemProt has been updated to more than 1...... properties. In addition, the user has the possibility to search by compound, target, pathway, disease and clinical effect. Genetic variations associated to target proteins were integrated, making it possible to plan pharmacogenetic studies and to suggest human response variability to drug. Finally...

  19. Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars

    Science.gov (United States)

    Nachon, M.; Clegg, S. N.; Mangold, N.; Schroeder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.; hide

    2014-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of :(1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of the targets [1;2] and (2) a Remote Micro Imager (RMI), for the imaging context of laser analysis [3]. Within the Gale crater, Curiosity traveled from Bradbury Landing through the Rocknest region and into Yellowknife Bay (YB). In the latter, abundant light-toned fracture-fill material were seen [4;5]. ChemCam analysis demonstrate that those fracture fills consist of calcium sulfates [6].

  20. Calibrating the ChemCam LIBS for Carbonate Minerals on Mars

    Science.gov (United States)

    Wiens, Roger C.; Clegg, Samuel M.; Ollila, Ann M.; Barefield, James E.; Lanza, Nina; Newsom, Horton E.

    2009-01-01

    The ChemCam instrument suite on board the NASA Mars Science Laboratory (MSL) rover includes the first LIBS instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment using the LIDS technique in order to better understand the in situ signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis (MVA) techniques. Composition is confirmed using scanning electron microscopy (SEM) techniques. Our initial results suggest that ChemCam can recognize and differentiate between carbonate materials on Mars.

  1. Comment on "An explanation for the charge on water's surface" by A. Gray-Weale and J. K. Beattie, Phys. Chem. Chem. Phys., 2009, 11, 10994

    Czech Academy of Sciences Publication Activity Database

    Vácha, Robert; Horinek, D.; Buchner, R.; Winter, B.; Jungwirth, Pavel

    2010-01-01

    Roč. 12, č. 42 (2010), s. 14362-14363 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z40550506 Keywords : surface charge * water * dielectric decrement Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2010

  2. ConfChem Conference on Flipped Classroom: Using a Blog to Flip a Classroom

    Science.gov (United States)

    Haile, January D.

    2015-01-01

    This communication summarizes one of the invited papers to the Flipped Classroom ACS Division of Chemical Education Committee on Computers in Chemical Education online ConfChem held from May 18 to June 24, 2014. Just in Time Teaching is a technique in which students read the material before class and respond to a few questions. In a first-year…

  3. Chem/bio sensing with non-classical light and integrated photonics.

    Science.gov (United States)

    Haas, J; Schwartz, M; Rengstl, U; Jetter, M; Michler, P; Mizaikoff, B

    2018-01-29

    Modern quantum technology currently experiences extensive advances in applicability in communications, cryptography, computing, metrology and lithography. Harnessing this technology platform for chem/bio sensing scenarios is an appealing opportunity enabling ultra-sensitive detection schemes. This is further facilliated by the progress in fabrication, miniaturization and integration of visible and infrared quantum photonics. Especially, the combination of efficient single-photon sources together with waveguiding/sensing structures, serving as active optical transducer, as well as advanced detector materials is promising integrated quantum photonic chem/bio sensors. Besides the intrinsic molecular selectivity and non-destructive character of visible and infrared light based sensing schemes, chem/bio sensors taking advantage of non-classical light sources promise sensitivities beyond the standard quantum limit. In the present review, recent achievements towards on-chip chem/bio quantum photonic sensing platforms based on N00N states are discussed along with appropriate recognition chemistries, facilitating the detection of relevant (bio)analytes at ultra-trace concentration levels. After evaluating recent developments in this field, a perspective for a potentially promising sensor testbed is discussed for reaching integrated quantum sensing with two fiber-coupled GaAs chips together with semiconductor quantum dots serving as single-photon sources.

  4. ChemNet: A Transferable and Generalizable Deep Neural Network for Small-Molecule Property Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Garrett B.; Siegel, Charles M.; Vishnu, Abhinav; Hodas, Nathan O.

    2017-12-08

    With access to large datasets, deep neural networks through representation learning have been able to identify patterns from raw data, achieving human-level accuracy in image and speech recognition tasks. However, in chemistry, availability of large standardized and labelled datasets is scarce, and with a multitude of chemical properties of interest, chemical data is inherently small and fragmented. In this work, we explore transfer learning techniques in conjunction with the existing Chemception CNN model, to create a transferable and generalizable deep neural network for small-molecule property prediction. Our latest model, ChemNet learns in a semi-supervised manner from inexpensive labels computed from the ChEMBL database. When fine-tuned to the Tox21, HIV and FreeSolv dataset, which are 3 separate chemical tasks that ChemNet was not originally trained on, we demonstrate that ChemNet exceeds the performance of existing Chemception models, contemporary MLP models that trains on molecular fingerprints, and it matches the performance of the ConvGraph algorithm, the current state-of-the-art. Furthermore, as ChemNet has been pre-trained on a large diverse chemical database, it can be used as a universal “plug-and-play” deep neural network, which accelerates the deployment of deep neural networks for the prediction of novel small-molecule chemical properties.

  5. The Chem-E-Car as a Vehicle for Service Learning through K-12 Outreach

    Science.gov (United States)

    Chirdon, William

    2017-01-01

    This article presents the results of combining the American Institute of Chemical Engineers' (AIChE) Chem-E-Car competition activities with engineering outreach to K-12 students in a service-learning course. Survey results are presented to show how the program develops technical skills as well as leadership, teamwork, and communication skills in…

  6. HExpoChem: a systems biology resource to explore human exposure to chemicals

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Jacobsen, Ulrik Plesner; Kalhauge, Christian Gram

    2013-01-01

    of computational biology approaches are needed to assess the health risks of chemical exposure. Here we present HExpoChem, a tool based on environmental chemicals and their bioactivities on human proteins with the objective of aiding the qualitative exploration of human exposure to chemicals. The chemical...

  7. ChemSession'08 - 5. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

    International Nuclear Information System (INIS)

    Madura, I.

    2008-01-01

    Book of Abstracts consists of short descriptions of presentations: 5 lectures and 127 posters presented during ChemSession'08 - 5 th Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found

  8. ChemSession'09 - 6. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

    International Nuclear Information System (INIS)

    2009-01-01

    Book of Abstracts contains short descriptions of presentations 3 lectures and 105 posters presented during ChemSession'09 - 6 th Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found

  9. Soil diversity and hydration as observed by ChemCam at Gale Crater, Mars

    NARCIS (Netherlands)

    Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schröder, S.; Cousin, A.; Berger, G.; Clegg, S.M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R.C.; Fabre, C.; Goetz, W.; Bish, D.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, R.; Rampe, E.; McConnochie, T.H.; Pinet, P.; Blaney, D.; Léveillé, R.; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J.G.; Bridges, N.; Clark, B.C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M.D.; Fisk, M.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M.B.; Melikechi, N.; Mezzacappa, A.; Mischna, M.A.; Moores, J.E.; Newsom, H.; Ollila, A.; Perez, R.; Renno, N.; Sirven, J.-B.; Tokar, R.; De La Torre, M.; D'Uston, L.; Vaniman, D.; Yingst, A.; MSL Science Team, the

    2013-01-01

    The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of

  10. The performance of the 'CentrifiChem' parallel fast analyser using packaged reagents.

    Science.gov (United States)

    Henry, P; Saunders, R A

    1975-05-01

    The CentrifiChem system was used with packaged reagent kits for the following determinations: albumin, alanine and aspartate aminotransferases, creatinine, glucose, and alpha-hydroxybutyrate and lactate dehydrogenases. The linearity obtainable for each assay was investigated, and particular attention was paid to finding the most suitable instrument settings.

  11. Data mining a small molecule drug screening representative subset from NIH PubChem.

    Science.gov (United States)

    Xie, Xiang-Qun; Chen, Jian-Zhong

    2008-03-01

    PubChem is a scientific showcase of the NIH Roadmap Initiatives. It is a compound repository created to facilitate information exchange and data sharing among the NIH Roadmap-funded Molecular Library Screening Center Network (MLSCN) and the scientific community. However, PubChem has more than 10 million records of compound information. It will be challenging to conduct a drug screening of the whole database of millions of compounds. Thus, the purpose of the present study was to develop a data mining cheminformatics approach in order to construct a representative and structure-diverse sublibrary from the large PubChem database. In this study, a new chemical diverse representative subset, rePubChem, was selected by whole-molecule chemistry-space matrix calculation using the cell-based partition algorithm. The representative subset was generated and was then subjected to evaluations by compound property analyses based on 1D and 2D molecular descriptors. The new subset was also examined and assessed for self-similarity analysis based on 2D molecular fingerprints in comparing with the source compound library. The new subset has a much smaller library size (540K compounds) with minimum similarity and redundancy without loss of the structural diversity and basic molecular properties of its parent library (5.3 million compounds). The new representative subset library generated could be a valuable structure-diverse compound resource for in silico virtual screening and in vitro HTS drug screening. In addition, the established subset generation method of using the combined cell-based chemistry-space partition metrics with pairwised 2D fingerprint-based similarity search approaches will also be important to a broad scientific community interested in acquiring structurally diverse compounds for efficient drug screening, building representative virtual combinatorial chemistry libraries for syntheses, and data mining large compound databases like the PubChem library in general.

  12. ChemInform Abstract: The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications.

    KAUST Repository

    Ebner, David C.; Bagdanoff, Jeffrey T.; Ferreira, Eric M.; McFadden, Ryan; Caspi, Daniel D.; Trend, Raissa M.; Stoltz, Brian M.

    2010-01-01

    ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

  13. ChemInform Abstract: The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications.

    KAUST Repository

    Ebner, David C.

    2010-03-30

    ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

  14. Sulfur Geochemical Analysis and Interpretation with ChemCam on the Curiosity Rover

    Science.gov (United States)

    Clegg, S. M.; Anderson, R. B.; Frydenvang, J.; Forni, O.; Newsom, H. E.; Blaney, D. L.; Maurice, S.; Wiens, R. C.

    2017-12-01

    The Curiosity rover has encountered many forms of sulfur including calcium sulfate veins [1], hydrated Mg sulfates, and Fe sulfates along the traverse through Gale crater. A new SO3 calibration model for the remote Laser-Induced Breakdown Spectroscopy (LIBS) technique used by the ChemCam instrument enables improved quantitative analysis of SO3, which has not been previously reported by ChemCam on a routine or quantitative basis. In this paper, the details of this new LIBS calibration model will be described and applied to many disparate Mars targets. Among them, Mavor contains a calcium sulfate vein surrounded by bedrock. In contrast, Jake M. is a float rock, Wernecke is a bedrock, Cumberland and Windjana are drill targets. In 2015 the ChemCam instrument team completed a re-calibration of major elements based on a significantly expanded set of >500 geochemical standards using the ChemCam testbed at Los Alamos National Laboratory [2]. In addition to these standards, the SO3 compositional range was recently extended with a series of doped samples containing various mixtures of Ca- and Mg-sulfate with basalt BHVO2. Spectra from these standards were processed per [4]. Calibration and Mars spectra were converted to peak-area-summed LIBS spectra that enables the SO3 calibration. These peak-area spectra were used to generate three overlapping partial least squares (PLS1) calibration sub-models as described by Anderson et al. [3, 5]. ChemCam analysis of Mavor involved a 3x3 raster in which locations 5 and 6 primarily probed Ca-sulfate material. The new ChemCam SO3 compositions for Mavor 5 and Mavor 6 are 48.6±1.2 and 50.3±1.2 wt% SO3, respectively. The LIBS spectra also recorded the presence of other elements that are likely responsible for the departure from pure Ca-sulfate chemistry. On the low-abundance side, the remaining 7 Mavor locations, Jake M., Cumberland, Windjana, and Wernecke all contain much lower SO3, between 1.4±0.5 wt% and 2.3±0.3 wt% SO3. [1] Nachon et

  15. The semantics of Chemical Markup Language (CML for computational chemistry : CompChem

    Directory of Open Access Journals (Sweden)

    Phadungsukanan Weerapong

    2012-08-01

    Full Text Available Abstract This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications.

  16. Diagenetic Features Analyzed by ChemCam/Curiosity at Pahrump Hills, Gale Crater, Mars

    Science.gov (United States)

    Nachon, M.; Mangold, N.; Cousin, A.; Forni, O.; Anderson, R. B.; Blank, J. G.; Calef, F.; Clegg, S.; Fabre, C.; Fisk, M.; hide

    2015-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of : (1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of targets and (2) a Remote Micro Imager (RMI), which provides imaging context for the LIBS. The LIBS/ChemCam performs analysis typically of spot sizes 350-550 micrometers in diameter, up to 7 meters from the rover. Within Gale crater, Curiosity traveled from Bradbury Landing toward the base of Mount Sharp, reaching Pahrump Hills outcrop circa sol 750. This region, as seen from orbit, represents the first exposures of lower Mount Sharp. In this abstract we focus on two types of features present within the Pahrump Hills outcrop: concretion features and light-toned veins.

  17. The semantics of Chemical Markup Language (CML) for computational chemistry : CompChem.

    Science.gov (United States)

    Phadungsukanan, Weerapong; Kraft, Markus; Townsend, Joe A; Murray-Rust, Peter

    2012-08-07

    : This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML) by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications.

  18. Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

    International Nuclear Information System (INIS)

    Payre, Valerie; Fabre, Cecile; Cousin, Agnes; Sautter, Violaine; Wiens, Roger Craig

    2017-01-01

    The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

  19. ChemSession'10: 7. Warsaw Seminar of the PhD Students in Chemistry. Abstracts

    International Nuclear Information System (INIS)

    Madura, I.

    2010-01-01

    Book of Abstracts contains short descriptions of presentations 4 lectures and 151 posters presented during ChemSession'10 - 7 th Warsaw Seminar of the PhD Students in Chemistry (Warsaw, 14.05.2010). Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry, application of the radionuclides and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also mentioned.

  20. Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

    Science.gov (United States)

    Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R. C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.-Y.; Lasue, J.; Ollila, A.; Rapin, W.; Maurice, S.; Nachon, M.; Le Deit, L.; Lanza, N.; Clegg, S.

    2017-03-01

    The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. These observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

  1. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuchynka, D. [Mirage Systems, Sunnyvale, CA (United States)

    1995-10-01

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. This report describes the ChemChar thermolytic detoxification process. The process is a thermal, chemically reductive technology that converts the organic portion of mixed wastes to a synthesis gas, while simultaneously absorbing volatile inorganics on a carbon-based char.

  2. ChemSession'11 - 8. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

    International Nuclear Information System (INIS)

    Madura, I.

    2011-01-01

    Book of Abstracts contains short descriptions of presentations: 4 lectures, 1 communication and 149 posters presented during ChemSession'11 - 8 th Warsaw Seminar of the PhD Students in Chemistry (Warsaw, 13.05.2011). Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry, application of the radionuclides and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also mentioned.

  3. An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

    OpenAIRE

    W. R. Sessions; H. E. Fuelberg; R. A. Kahn; D. M. Winker

    2010-01-01

    The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia.

  4. Benchmarking Ligand-Based Virtual High-Throughput Screening with the PubChem Database

    Directory of Open Access Journals (Sweden)

    Mariusz Butkiewicz

    2013-01-01

    Full Text Available With the rapidly increasing availability of High-Throughput Screening (HTS data in the public domain, such as the PubChem database, methods for ligand-based computer-aided drug discovery (LB-CADD have the potential to accelerate and reduce the cost of probe development and drug discovery efforts in academia. We assemble nine data sets from realistic HTS campaigns representing major families of drug target proteins for benchmarking LB-CADD methods. Each data set is public domain through PubChem and carefully collated through confirmation screens validating active compounds. These data sets provide the foundation for benchmarking a new cheminformatics framework BCL::ChemInfo, which is freely available for non-commercial use. Quantitative structure activity relationship (QSAR models are built using Artificial Neural Networks (ANNs, Support Vector Machines (SVMs, Decision Trees (DTs, and Kohonen networks (KNs. Problem-specific descriptor optimization protocols are assessed including Sequential Feature Forward Selection (SFFS and various information content measures. Measures of predictive power and confidence are evaluated through cross-validation, and a consensus prediction scheme is tested that combines orthogonal machine learning algorithms into a single predictor. Enrichments ranging from 15 to 101 for a TPR cutoff of 25% are observed.

  5. Cleanup of metals and hydrocarbons contaminated soils using the ChemTech process

    International Nuclear Information System (INIS)

    Stephenson, R.; Yan, V.; Lim, S.

    1997-01-01

    The ChemTech soil treatment process, an on-site ex-situ system, comprised of a three-phase fluidized bed to scour, emulsify and chemically leach soil contaminants into a process water, was described. The cleaned soils are then removed from the process circuit by means of a hydrodynamic classifier. At this point they are suitable for return to the excavation site. The process was demonstrated on a pilot scale in January 1997 by Klohn-Crippen Consultants at a demonstration program of emerging and innovative technologies sponsored by the Bay Area Defence Conversion Action Team (BADCAT), to assist with the remediation of twelve closing military bases in the San Francisco area. The ChemTest demonstration involved the removal of copper, chromium, lead and zinc from the Hunter Point Naval Reserve, plus treatability tests on a number of other contaminated soil samples. The ChemTech process was selected by federal and state regulatory agencies from 21 proposed technologies on the basis of performance, effectiveness, low cost, and absence of secondary environmental impacts. This paper provides details of the demonstration program, addresses the applicability of the technology to other sites, and provides cost estimates of unit cleanup costs. 3 refs., 4 tabs., 4 figs

  6. A CNES remote operations center for the MSL ChemCam instrument

    Energy Technology Data Exchange (ETDEWEB)

    Wiens, Roger C [Los Alamos National Laboratory; Lafaille, Vivian [CNES; Lorgny, Eric [CNES; Baroukh, Julien [CNES; Gaboriaud, Alain [CNES; Saccoccio, Muriel [CNES; Perez, Rene [CNES; Gasnault, Olivier [CNRS/CESR; Maurice, Sylvestre [CNRS/CESR; Blaney, Diana [JPL

    2010-01-01

    For the first time, a CNES remote operations center in Toulouse will be involved in the tactical operations of a Martian rover in order to operate the ChemCam science instrument in the framework of the NASA MSL (Mars Science Laboratory) mission in 2012. CNES/CESR and LANL have developed and delivered to JPL the ChemCam (Chemistry Camera) instrument located on the top of mast and in the body of the rover. This instrument incorporates a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI) for determining elemental compositions of rock targets or soil samples at remote distances from the rover (2-7 m). An agreement has been achieved for operating ChemCam, alternatively, from Toulouse (FR) and Los Alamos (NM, USA), through the JPL ground data system in Pasadena (CA, USA) for a complete Martian year (2 years on Earth). After a brief overview of the MSL mission, this paper presents the instrument, the mission operational system and JPL organization requirements for the scientific investigators (PI and Co-Is). This paper emphasizes innovations applied on the ground segment components and on the operational approach to satisfy the requirements and constraints due to these shared and distributed operations over the world.

  7. OrChem - An open source chemistry search engine for Oracle®

    Science.gov (United States)

    2009-01-01

    Background Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Results Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. Availability OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net. PMID:20298521

  8. OrChem - An open source chemistry search engine for Oracle(R).

    Science.gov (United States)

    Rijnbeek, Mark; Steinbeck, Christoph

    2009-10-22

    Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net.

  9. NutriChem: a systems chemical biology resource to explore the medicinal value of plant-based foods

    DEFF Research Database (Denmark)

    Jensen, Kasper; Panagiotou, Gianni; Kouskoumvekaki, Irene

    2015-01-01

    million MEDLINE abstracts for information thatlinks plant-based foods with their small moleculecomponents and human disease phenotypes. Nu-triChem contains text-mined data for 18478 pairs of1772 plant-based foods and 7898 phytochemicals,and 6242 pairs of 1066 plant-based foods and 751diseases. In addition......,there is currently no exhaustive resource on thehealth benefits associated to specific dietary inter-ventions, or a resource covering the broad molecu-lar content of food. Here we present the first releaseof NutriChem, available athttp://cbs.dtu.dk/services/NutriChem-1.0, a database generated by text miningof 21...

  10. Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

    Science.gov (United States)

    McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

    2018-06-01

    We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

  11. An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

    Directory of Open Access Journals (Sweden)

    W. R. Sessions

    2011-06-01

    Full Text Available The Weather Research and Forecasting Model (WRF is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia.

    One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3–5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE. Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors.

    When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3–5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less

  12. An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

    Science.gov (United States)

    Sessions, W. R.; Fuelberg, H. E.; Kahn, R. A.; Winker, D. M.

    2011-06-01

    The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia. One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3-5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA) and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE). Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors. When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3-5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less agreement with observed plume heights

  13. Improved Near Real Time WRF-Chem Volcanic Emission Prediction and Impacts of Ash Aerosol on Weather.

    Science.gov (United States)

    Stuefer, M.; Webley, P. W.; Hirtl, M.

    2017-12-01

    We use the numerical Weather Research Forecasting (WRF) model with online Chemistry (WRF-Chem) to investigate the regional effects of volcanic aerosol on weather. A lot of observational data have become available since the Icelandic eruption of Eyjafjallajökull in spring 2010. The observed plume characteristics and meteorological data have been exploited for volcanic WRF-Chem case studies. We concluded that the Eyjafjallajökull ash plume resulted in significant direct aerosol effects altering the state of the atmosphere over large parts of Europe. The WRF-Chem model runs show near surface temperature differences up to 3ºC, altered vertical stability, changed pressure- and wind fields within the atmosphere loaded with ash aerosol. The modeled results have been evaluated with lidar network data, and ground and balloon based observations all over Europe. Besides case studies, we use WRF-Chem to build an improved volcanic ash decision support system that NOAA can use within the Volcanic Ash Advisory Center (VAAC) system. Realistic eruption source parameter (ESP) estimates are a main challenge in predicting volcanic emission dispersion in near real time. We implemented historic ESP into the WRF-Chem preprocessing routine, which can be used as a first estimate to assess a volcanic plume once eruption activity is reported. In a second step, a range of varying plume heights has been associated with the different ash variables within WRF-Chem, resulting in an assembly of different plume scenarios within one WRF-Chem model run. Once there is plume information available from ground or satellite observations, the forecaster has the option to select the corresponding ash variable that best matches the observations. In addition we added an automatic domain generation tool to create near real time WRF-Chem model runs anywhere on the globe by reducing computing expenses at the same time.

  14. Effects on Student Achievement in General Chemistry Following Participation in an Online Preparatory Course. ChemPrep, a Voluntary, Self-Paced, Online Introduction to Chemistry

    Science.gov (United States)

    Botch, Beatrice; Day, Roberta; Vining, William; Stewart, Barbara; Rath, Kenneth; Peterfreund, Alan; Hart, David

    2007-03-01

    ChemPrep was developed to be a stand-alone preparatory short-course to help students succeed in general chemistry. It is Web-based and delivered using the OWL system. Students reported that the ChemPrep materials (short information pages, parameterized questions with detailed feedback, tutorials, and answers to questions through the OWL message system) permitted them to work independently without the need for textbook or lecture. On average, students who completed ChemPrep had higher grades in the subsequent GenChem, Nursing, and Honors chemistry courses, with a greater percentage achieving a grade of C- or higher. Participation in ChemPrep was voluntary, and more women than men responded. Students in the Honors course enrolled in ChemPrep in higher percentages than students in GenChem and Nursing. SAT and departmental math placement exam scores were used as proxy measures of prior achievement and ability. Based on these, Honors chemistry ChemPrep users were on par with their peers but performed better in the course than non-users. In GenChem and Nursing chemistry courses, ChemPrep helped students of high prior achievement and ability perform better than their achievement scores would predict. Weaker or less motivated students did not respond to the voluntary offerings of ChemPrep in the same numbers as stronger or more motivated students, and we are seeking alternate ways to reach this population.

  15. Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin

    2014-12-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.

  16. Incorporation of a Chemical Equilibrium Equation of State into LOCI-Chem

    Science.gov (United States)

    Cox, Carey F.

    2005-01-01

    Renewed interest in development of advanced high-speed transport, reentry vehicles and propulsion systems has led to a resurgence of research into high speed aerodynamics. As this flow regime is typically dominated by hot reacting gaseous flow, efficient models for the characteristic chemical activity are necessary for accurate and cost effective analysis and design of aerodynamic vehicles that transit this regime. The LOCI-Chem code recently developed by Ed Luke at Mississippi State University for NASA/MSFC and used by NASA/MSFC and SSC represents an important step in providing an accurate, efficient computational tool for the simulation of reacting flows through the use of finite-rate kinetics [3]. Finite rate chemistry however, requires the solution of an additional N-1 species mass conservation equations with source terms involving reaction kinetics that are not fully understood. In the equilibrium limit, where the reaction rates approach infinity, these equations become very stiff. Through the use of the assumption of local chemical equilibrium the set of governing equations is reduced back to the usual gas dynamic equations, and thus requires less computation, while still allowing for the inclusion of reacting flow phenomenology. The incorporation of a chemical equilibrium equation of state module into the LOCI-Chem code was the primary objective of the current research. The major goals of the project were: (1) the development of a chemical equilibrium composition solver, and (2) the incorporation of chemical equilibrium solver into LOCI-Chem. Due to time and resource constraints, code optimization was not considered unless it was important to the proper functioning of the code.

  17. Exploration of Mars with the ChemCam LIBS Instrument and the Curiosity Rover

    Science.gov (United States)

    Newsom, Horton E.

    2016-01-01

    The Mars Science Laboratory (MSL) Curiosity rover landed on Mars in August 2012, and has been exploring the planet ever since. Dr. Horton E. Newsom will discuss the MSL's design and main goal, which is to characterize past environments that may have been conducive to the evolution and sustainability of life. He will also discuss Curiosity's science payload, and remote sensing, analytical capabilities, and direct discoveries of the Chemistry & Camera (ChemCam) instrument, which is the first Laser Induced Breakdown Spectrometer (LIBS) to operate on another planetary surface and determine the chemistry of the rocks and soils.

  18. ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars

    Science.gov (United States)

    Johnson, Jeffrey R.; Bell, J. F.; Bender, S.; Blaney, D.; Cloutis, E.; DeFlores, L.; Ehlmann, B.; Gasnault, O.; Gondet, B.; Kinch, K.; Lemmon, M.; Le Mouélic, S.; Maurice, S.; Rice, M.; Wiens, R. C.

    2015-03-01

    The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400-840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets' housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (rocks and soils match those from orbital observations and multispectral data from the MSL Mastcam camera. Preliminary analyses of the band depths, spectral slopes, and reflectance ratios of the more than 2000 spectra taken during the first year of MSL operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components. Initial comparisons of ChemCam spectra to laboratory spectra of minerals and Mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks. Magnesium-rich "raised ridges" tend to exhibit distinct near-infrared slopes. The ferric absorption downturn typically found for martian materials at rocks and drill tailings, consistent with their more ferrous nature. Calcium-sulfate veins exhibit the highest relative reflectances observed, but are still relatively red owing to the effects of residual dust. Such dust is overall less prominent on rocks sampled within the "blast zone" immediately surrounding the landing site. These samples were likely affected by the landing thrusters, which partially removed the ubiquitous dust coatings. Increased dust coatings on the calibration targets during the first year of the mission were documented by the ChemCam passive measurements as well. Ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance

  19. ChemAND{sup TM} - a system health monitor for plant chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C.W.; Mitchel, G.R.; Balakrishnan, P.V.; Tosello, G

    1999-07-01

    Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation and feeds these parameters to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently has two analytical models developed for the balance-of-plant. CHEMSOLV calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information will be used by operations personnel to evaluate the potential for SG tube corrosion in the crevice region. CHEMSOLV also calculates chemistry conditions throughout the steam-cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. A second model, SLUDGE, calculates the deposit loading in the SG as a function of time, based on concentrations of corrosion product in the final feedwater and plant operating conditions. Operations personnel can use this information to predict where to inspect and when to clean. In a future development, SLUDGE will track deposit loading arising from start-up crud bursts and will be used in conjunction with the thermohydraulics code, THIRST, to

  20. Nanoplatforms for Detection, Remediation and Protection Against Chem-Bio Warfare

    Science.gov (United States)

    Denkbaş, E. B.; Bayram, C.; Kavaz, D.; Çirak, T.; Demirbilek, M.

    Chemical and biological substances have been used as warfare agents by terrorists by varying degree of sophistication. It is critical that these agents be detected in real-time with high level of sensitively, specificity, and accuracy. Many different types of techniques and systems have been developed to detect these agents. But there are some limitations in these conventional techniques and systems. Limitations include the collection, handling and sampling procedures, detection limits, sample transfer, expensive equipment, personnel training, and detection materials. Due to the unique properties such as quantum effect, very high surface/volume ratio, enhanced surface reactivity, conductivity, electrical and magnetic properties of the nanomaterials offer great opportunity to develop very fast, sensitive, accurate and cost effective detection techniques and systems to detect chemical and biological (chem.-bio) warfare agents. Furthermore, surface modification of the materials is very easy and effective way to get functional or smart surfaces to be used as nano-biosensor platform. In that respect many different types of nanomaterials have been developed and used for the detection, remediation and protection, such as gold and silver nanoparticles, quantum dots, Nano chips and arrays, fluorescent polymeric and magnetic nanoparticles, fiber optic and cantilever based nanobiosensors, nanofibrillar nanostructures etc. This study summarizes preparation and characterization of nanotechnology based approaches for the detection of and remediation and protection against chem.-bio warfare agents.

  1. The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard Curiosity

    Science.gov (United States)

    Le Deit, Laetitia; Mangold, Nicolas; Forni, Olivier; Cousin, Agnes; Lasue, Jeremie; Schröder, Susanne; Wiens, Roger C.; Sumner, Dawn Y.; Fabre, Cecile; Stack, Katherine M.; Anderson, Ryan; Blaney, Diana L.; Clegg, Samuel M.; Dromart, Gilles; Fisk, Martin; Gasnault, Olivier; Grotzinger, John P.; Gupta, Sanjeev; Lanza, Nina; Le Mouélic, Stephane; Maurice, Sylvestre; McLennan, Scott M.; Meslin, Pierre-Yves; Nachon, Marion; Newsom, Horton E.; Payre, Valerie; Rapin, William; Rice, Melissa; Sautter, Violaine; Treiman, Alan H.

    2016-01-01

    The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. From ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations reveals that the mean K2O abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.

  2. Inclusion of biomass burning in WRF-Chem: impact of wildfires on weather forecasts

    Directory of Open Access Journals (Sweden)

    G. Grell

    2011-06-01

    Full Text Available A plume rise algorithm for wildfires was included in WRF-Chem, and applied to look at the impact of intense wildfires during the 2004 Alaska wildfire season on weather simulations using model resolutions of 10 km and 2 km. Biomass burning emissions were estimated using a biomass burning emissions model. In addition, a 1-D, time-dependent cloud model was used online in WRF-Chem to estimate injection heights as well as the vertical distribution of the emission rates. It was shown that with the inclusion of the intense wildfires of the 2004 fire season in the model simulations, the interaction of the aerosols with the atmospheric radiation led to significant modifications of vertical profiles of temperature and moisture in cloud-free areas. On the other hand, when clouds were present, the high concentrations of fine aerosol (PM2.5 and the resulting large numbers of Cloud Condensation Nuclei (CCN had a strong impact on clouds and cloud microphysics, with decreased precipitation coverage and precipitation amounts during the first 12 h of the integration. During the afternoon, storms were of convective nature and appeared significantly stronger, probably as a result of both the interaction of aerosols with radiation (through an increase in CAPE as well as the interaction with cloud microphysics.

  3. ChemEngine: harvesting 3D chemical structures of supplementary data from PDF files.

    Science.gov (United States)

    Karthikeyan, Muthukumarasamy; Vyas, Renu

    2016-01-01

    Digital access to chemical journals resulted in a vast array of molecular information that is now available in the supplementary material files in PDF format. However, extracting this molecular information, generally from a PDF document format is a daunting task. Here we present an approach to harvest 3D molecular data from the supporting information of scientific research articles that are normally available from publisher's resources. In order to demonstrate the feasibility of extracting truly computable molecules from PDF file formats in a fast and efficient manner, we have developed a Java based application, namely ChemEngine. This program recognizes textual patterns from the supplementary data and generates standard molecular structure data (bond matrix, atomic coordinates) that can be subjected to a multitude of computational processes automatically. The methodology has been demonstrated via several case studies on different formats of coordinates data stored in supplementary information files, wherein ChemEngine selectively harvested the atomic coordinates and interpreted them as molecules with high accuracy. The reusability of extracted molecular coordinate data was demonstrated by computing Single Point Energies that were in close agreement with the original computed data provided with the articles. It is envisaged that the methodology will enable large scale conversion of molecular information from supplementary files available in the PDF format into a collection of ready- to- compute molecular data to create an automated workflow for advanced computational processes. Software along with source codes and instructions available at https://sourceforge.net/projects/chemengine/files/?source=navbar.Graphical abstract.

  4. Aerosol comparisons between sunphotometry / sky radiometry and the GEOS-Chem model

    Science.gov (United States)

    Chaubey, J. P.; Hesaraki, S.; O'Neill, N. T.; Saha, A.; Martin, R.; Lesins, G. B.; Abboud, I.

    2014-12-01

    Comparisons of aerosol optical depth (AOD), spectral AOD parameters and microphysical parameters derived from AEROCAN / AERONET sunphotometer / sky radiometer data acquired over Canada were compared with GEOS-Chem (Geos5,v9-01-03) estimations. The Canadian sites were selected so as to encompass a representative variety of different aerosol types ranging from fine mode (submicron) pollution and smoke aerosols, coarse mode (supermicron) dust, fine and coarse mode marine aerosols, volcanic (fine mode) sulfates and volcanic (coarse mode) ash, etc). A particular focus was placed on comparisons at remote Canadian sites with a further focus on Arctic sites. The analysis included meteorological-scale event comparisons as well as seasonal and yearly comparisons on a climatological scale. The investigations were given a further aerosol type context by comparing optical retrievals of fine and coarse mode AOD with the AODs of the different aerosol types predicted by GEOS-Chem. The effects of temporal and spectral cloud screening of the sunphotometer data on the quality and robustness of these comparisons was the object of an important supporting investigation. The results of this study will be presented for a 3 year period from 2009 to 2011.

  5. Source apportionment of atmospheric mercury pollution in China using the GEOS-Chem model

    International Nuclear Information System (INIS)

    Wang, Long; Wang, Shuxiao; Zhang, Lei; Wang, Yuxuan; Zhang, Yanxu; Nielsen, Chris; McElroy, Michael B.; Hao, Jiming

    2014-01-01

    China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35–50% of THg concentration and 50–70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China. - Highlights: • China's anthropogenic mercury emission was 643.1 t in 2007. • GEOS-Chem model well reproduces the background Hg concentrations. • Anthropogenic emissions contribute 35–50% of Hg concentrations in polluted regions. • The priorities for mercury control in polluted regions are identified. - Anthropogenic Hg emissions are updated and their impacts on atmospheric mercury concentrations and depositions are quantified for China

  6. Calibration of the MSL/ChemCam/LIBS Remote Sensing Composition Instrument

    Science.gov (United States)

    Wiens, R. C.; Maurice S.; Bender, S.; Barraclough, B. L.; Cousin, A.; Forni, O.; Ollila, A.; Newsom, H.; Vaniman, D.; Clegg, S.; hide

    2011-01-01

    The ChemCam instrument suite on board the 2011 Mars Science Laboratory (MSL) Rover, Curiosity, will provide remote-sensing composition information for rock and soil samples within seven meters of the rover using a laser-induced breakdown spectroscopy (LIBS) system, and will provide context imaging with a resolution of 0.10 mradians using the remote micro-imager (RMI) camera. The high resolution is needed to image the small analysis footprint of the LIBS system, at 0.2-0.6 mm diameter. This fine scale analytical capability will enable remote probing of stratigraphic layers or other small features the size of "blueberries" or smaller. ChemCam is intended for rapid survey analyses within 7 m of the rover, with each measurement taking less than 6 minutes. Repeated laser pulses remove dust coatings and provide depth profiles through weathering layers, allowing detailed investigation of rock varnish features as well as analysis of the underlying pristine rock composition. The LIBS technique uses brief laser pulses greater than 10 MW/square mm to ablate and electrically excite material from the sample of interest. The plasma emits photons with wavelengths characteristic of the elements present in the material, permitting detection and quantification of nearly all elements, including the light elements H, Li, Be, B, C, N, O. ChemCam LIBS projects 14 mJ of 1067 nm photons on target and covers a spectral range of 240-850 nm with resolutions between 0.15 and 0.60 nm FWHM. The Nd:KGW laser is passively cooled and is tuned to provide maximum power output from -10 to 0 C, though it can operate at 20% degraded energy output at room temperature. Preliminary calibrations were carried out on the flight model (FM) in 2008. However, the detectors were replaced in 2009, and final calibrations occurred in April-June, 2010. This presentation describes the LIBS calibration and characterization procedures and results, and details plans for final analyses during rover system thermal testing

  7. Design and Development of ChemInfoCloud: An Integrated Cloud Enabled Platform for Virtual Screening.

    Science.gov (United States)

    Karthikeyan, Muthukumarasamy; Pandit, Deepak; Bhavasar, Arvind; Vyas, Renu

    2015-01-01

    The power of cloud computing and distributed computing has been harnessed to handle vast and heterogeneous data required to be processed in any virtual screening protocol. A cloud computing platorm ChemInfoCloud was built and integrated with several chemoinformatics and bioinformatics tools. The robust engine performs the core chemoinformatics tasks of lead generation, lead optimisation and property prediction in a fast and efficient manner. It has also been provided with some of the bioinformatics functionalities including sequence alignment, active site pose prediction and protein ligand docking. Text mining, NMR chemical shift (1H, 13C) prediction and reaction fingerprint generation modules for efficient lead discovery are also implemented in this platform. We have developed an integrated problem solving cloud environment for virtual screening studies that also provides workflow management, better usability and interaction with end users using container based virtualization, OpenVz.

  8. In situ detection of boron by ChemCam on Mars

    Science.gov (United States)

    Gasda, Patrick J.; Haldeman, Ethan B.; Wiens, Roger C.; Rapin, William; Bristow, Thomas F.; Bridges, John C.; Schwenzer, Susanne P.; Clark, Benton; Herkenhoff, Kenneth; Frydenvang, Jens; Lanza, Nina L.; Maurice, Sylvestre; Clegg, Samuel; Delapp, Dorothea M.; Sanford, Veronica L.; Bodine, Madeleine R.; McInroy, Rhonda

    2017-09-01

    We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.

  9. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying

    2015-01-01

    A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they

  10. Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

    Science.gov (United States)

    Zhang, B.; Huang, J.; Chen, S.

    2017-12-01

    An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captured the spatial and temporal distributions of meteorological factors and dust aerosols over East Asia. This summer dust storm was initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air was transported southward and further enhanced in the narrow valleys of the Altai and Tianshan Mountains, which resulted in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD were as high as 54 μg m-2 s-1 on June 25th. The dust aerosols from the TD then swept across Inner Mongolia, Ningxia and Mongolia, and some were also transported eastward to Beijing, Tianjin, the Hebei region, and even South Korea and Japan. The simulations further showed that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heat the atmosphere at a maximum heating rate of 0.14 k day-1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The dust event-averaged direct radiative forcing induced by dust particles over the TD at all-sky was -6.0, -16.8 and 10.8 W m-2 at the top of the atmosphere, the surface, and in the atmosphere, respectively.

  11. Mixed Waste Treatment Using the ChemChar Thermolytic Detoxification Technique

    International Nuclear Information System (INIS)

    Kuchynka, D.J.

    1997-01-01

    This R and D program addresses the treatment of mixed waste employing the ChemChar Thermolytic Detoxification process. Surrogate mixed waste streams will be treated in a four inch diameter, continuous feed, adiabatic reactor with the goal of meeting all regulatory treatment levels for the contaminants in the surrogates with the concomitant production of contaminant free by-products. Successful completion of this program will show that organic contaminants in mixed waste surrogates will be converted to a clean, energy rich synthesis gas capable of being used, without further processing, for power or heat generation. The inorganic components in the surrogates will be found to be adsorbed on a macroporous coal char activated carbon substrate which is mixed with the waste prior to treatment. These contaminants include radioactive metal surrogate species, RCRA hazardous metals and any acid gases formed during the treatment process. The program has three main tasks that will be performed to meet the above objectives. The first task is the design and construction of the four inch reactor at Mirage Systems in Sunnyvale, CA. The second task is production and procurement of the activated carbon char employed in the ChemChartest runs and identification of two surrogate mixed wastes. The last task is testing and operation of the reactor on char/surrogate waste mixtures to be performed at the University of Missouri. The deliverables for the project are a Design Review Report, Operational Test Plan, Topical Report and Final Report. This report contains only the results of the design and construction carbon production-surrogate waste identification tasks.Treatment of the surrogate mixed wastes has just begun and will not be reported in this version of the Final Report. The latter will be reported in the final version of the Final Report

  12. Viral vectors for gene modification of plants as chem/bio sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Manginell, Monica; Harper, Jason C.; Arango, Dulce C.; Brozik, Susan Marie; Dolan, Patricia L.

    2006-11-01

    Chemical or biological sensors that are specific, sensitive, and robust allowing intelligence gathering for verification of nuclear non-proliferation treaty compliance and detouring production of weapons of mass destruction are sorely needed. Although much progress has been made in the area of biosensors, improvements in sensor lifetime, robustness, and device packaging are required before these devices become widely used. Current chemical and biological detection and identification techniques require less-than-covert sample collection followed by transport to a laboratory for analysis. In addition to being expensive and time consuming, results can often be inconclusive due to compromised sample integrity during collection and transport. We report here a demonstration of a plant based sensor technology which utilizes mature and seedling plants as chemical sensors. One can envision genetically modifying native plants at a site of interest that can report the presence of specific toxins or chemicals. In this one year project we used a developed inducible expression system to show the feasibility of plant sensors. The vector was designed as a safe, non-infectious vector which could be used to invade, replicate, and introduce foreign genes into mature host plants that then allow the plant to sense chem/bio agents. The genes introduced through the vector included a reporter gene that encodes for green fluorescent protein (GFP) and a gene that encodes for a mammalian receptor that recognizes a chemical agent. Specifically, GFP was induced by the presence of 17-{beta}-Estradiol (estrogen). Detection of fluorescence indicated the presence of the target chemical agent. Since the sensor is a plant, costly device packaging development or manufacturing of the sensor were not required. Additionally, the biological recognition and reporting elements are maintained in a living, natural environment and therefore do not suffer from lifetime disadvantages typical of most biosensing

  13. Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars

    Science.gov (United States)

    Nachon, Marion; Mangold, Nicolas; Forni, Olivier; Kah, Linda C.; Cousin, Agnes; Wiens, Roger C.; Anderson, Ryan; Blaney, Diana L.; Blank, Jen G.; Calef, Fred J.; Clegg, Samuel M.; Fabre, Cecile; Fisk, Martin R.; Gasnault, Olivier; Grotzinger, John P.; Kronyak, Rachel; Lanza, Nina L.; Lasue, Jeremie; Le Deit, Laetitia; Le Mouelic, Stephane; Maurice, Sylvestre; Meslin, Pierre-Yves; Oehler, D. Z.; Payre, Valerie; Rapin, William; Schroder, Susanne; Stack, Katherine M.; Sumner, Dawn

    2017-01-01

    The Curiosity rover's campaign at Pahrump Hills provides the first analyses of lower Mount Sharp strata. Here we report ChemCam elemental composition of a diverse assemblage of post-depositional features embedded in, or cross-cutting, the host rock. ChemCam results demonstrate their compositional diversity, especially compared to the surrounding host rock: (i) Dendritic aggregates and relief enhanced features, characterized by a magnesium enhancement and sulfur detection, and interpreted as Mg-sulfates; (ii) A localized observation that displays iron enrichment associated with sulfur, interpreted as Fe-sulfate; (iii) Dark raised ridges with varying Mg- and Ca-enriched compositions compared to host rock; (iv) Several dark-toned veins with calcium enhancement associated with fluorine detection, interpreted as fluorite veins. (v) Light-toned veins with enhanced calcium associated with sulfur detection, and interpreted as Ca-sulfates. The diversity of the Pahrump Hills diagenetic assemblage suggests a complex post-depositional history for fine-grained sediments for which the origin has been interpreted as fluvial and lacustrine. Assessment of the spatial and relative temporal distribution of these features shows that the Mg-sulfate features are predominant in the lower part of the section, suggesting local modification of the sediments by early diagenetic fluids. In contrast, light-toned Ca-sulfate veins occur in the whole section and cross-cut all other features. A relatively late stage shift in geochemical conditions could explain this observation. The Pahrump Hills diagenetic features have no equivalent compared to targets analyzed in other locations at Gale crater. Only the light-toned Ca-sulfate veins are present elsewhere, along Curiosity's path, suggesting they formed through a common late-stage process that occurred at over a broad area.

  14. Regional modelling of polycyclic aromatic hydrocarbons: WRF-Chem-PAH model development and East Asia case studies

    Science.gov (United States)

    Mu, Qing; Lammel, Gerhard; Gencarelli, Christian N.; Hedgecock, Ian M.; Chen, Ying; Přibylová, Petra; Teich, Monique; Zhang, Yuxuan; Zheng, Guangjie; van Pinxteren, Dominik; Zhang, Qiang; Herrmann, Hartmut; Shiraiwa, Manabu; Spichtinger, Peter; Su, Hang; Pöschl, Ulrich; Cheng, Yafang

    2017-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants, with increasing emissions in pace with economic development in East Asia, but their distribution and fate in the atmosphere are not yet well understood. We extended the regional atmospheric chemistry model WRF-Chem (Weather Research Forecast model with Chemistry module) to comprehensively study the atmospheric distribution and the fate of low-concentration, slowly degrading semivolatile compounds. The WRF-Chem-PAH model reflects the state-of-the-art understanding of current PAHs studies with several new or updated features. It was applied for PAHs covering a wide range of volatility and hydrophobicity, i.e. phenanthrene, chrysene and benzo[a]pyrene, in East Asia. Temporally highly resolved PAH concentrations and particulate mass fractions were evaluated against observations. The WRF-Chem-PAH model is able to reasonably well simulate the concentration levels and particulate mass fractions of PAHs near the sources and at a remote outflow region of East Asia, in high spatial and temporal resolutions. Sensitivity study shows that the heterogeneous reaction with ozone and the homogeneous reaction with the nitrate radical significantly influence the fate and distributions of PAHs. The methods to implement new species and to correct the transport problems can be applied to other newly implemented species in WRF-Chem.

  15. Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

    Energy Technology Data Exchange (ETDEWEB)

    Croft, B. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Pierce, J.R. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Colorado State Univ., Fort Collins, CO (United States); Martin, R.V. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2014-07-01

    Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents {sup 137}Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of {sup 137}Cs and {sup 133}Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated {sup 137}Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound {sup 137}Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean {sup 137}Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the {sup 137}Cs injected at the Fukushima site (likely due to precipitation shortly after

  16. Constraints on Eurasian ship NOx emissions using OMI NO2 observations and GEOS-Chem

    Science.gov (United States)

    Vinken, Geert C. M.; Boersma, Folkert; van Donkelaar, Aaron; Zhang, Lin

    2013-04-01

    Ships emit large quantities of nitrogen oxides (NOx = NO + NO2), important precursors for ozone (O3) and particulate matter formation. Ships burn low-grade marine heavy fuel due to the limited regulations that exist for the maritime sector in international waters. Previous studies showed that global ship NOx emission inventories amount to 3.0-10.4 Tg N per year (15-30% of total NOx emissions), with most emissions close to land and affecting air quality in densely populated coastal regions. Bottom-up inventories depend on the extrapolation of a relatively small number of measurements that are often unable to capture annual emission changes and can suffer from large uncertainties. Satellites provide long-term, high-resolution retrievals that can be used to improve emission estimates. In this study we provide top-down constraints on ship NOx emissions in major European ship routes, using observed NO2 columns from the Ozone Monitoring Instrument (OMI) and NO2 columns simulated with the nested (0.5°×0.67°) version of the GEOS-Chem chemistry transport model. We use a plume-in-grid treatment of ship NOx emissions to account for in-plume chemistry in our model. We ensure consistency between the retrievals and model simulations by using the high-resolution GEOS-Chem NO2 profiles as a priori. We find evidence that ship emissions in the Mediterranean Sea are geographically misplaced by up to 150 km and biased high by a factor of 4 as compared to the most recent (EMEP) ship emission inventory. Better agreement is found over the shipping lane between Spain and the English Channel. We extend our approach and also provide constraints for major ship routes in the Red Sea and Indian Ocean. Using the full benefit of the long-term retrieval record of OMI, we present a new Eurasian ship emission inventory for the years 2005 to 2010, based on the EMEP and AMVER-ICOADS inventories, and top-down constraints from the satellite retrievals. Our work shows that satellite retrievals can

  17. ChemCam results from the Shaler outcrop in Gale crater, Mars

    Science.gov (United States)

    Anderson, Ryan B.; Bridges, J.C.; Williams, A.; Edgar, L.; Ollila, A.; Williams, J.; Nachon, Marion; Mangold, N.; Fisk, M.; Schieber, J.; Gupta, S.; Dromart, G.; Wiens, R.; Le Mouélic, Stéphane; Forni, O.; Lanza, N.; Mezzacappa, Alissa; Sautter, V.; Blaney, D.; Clark, B.; Clegg, S.; Gasnault, O.; Lasue, J.; Léveillé, Richard; Lewin, E.; Lewis, K.W.; Maurice, S.; Newsom, H.; Schwenzer, S.P.; Vaniman, D.

    2015-01-01

    The ChemCam campaign at the fluvial sedimentary outcrop “Shaler” resulted in observations of 28 non-soil targets, 26 of which included active laser induced breakdown spectroscopy (LIBS), and all of which included Remote Micro-Imager (RMI) images. The Shaler outcrop can be divided into seven facies based on grain size, texture, color, resistance to erosion, and sedimentary structures. The ChemCam observations cover Facies 3 through 7. For all targets, the majority of the grains were below the limit of the RMI resolution, but many targets had a portion of resolvable grains coarser than ∼0.5 mm. The Shaler facies show significant scatter in LIBS spectra and compositions from point to point, but several key compositional trends are apparent, most notably in the average K2O content of the observed facies. Facies 3 is lower in K2O than the other facies and is similar in composition to the “snake,” a clastic dike that occurs lower in the Yellowknife Bay stratigraphic section. Facies 7 is enriched in K2O relative to the other facies and shows some compositional and textural similarities to float rocks near Yellowknife Bay. The remaining facies (4, 5, and 6) are similar in composition to the Sheepbed and Gillespie Lake members, although the Shaler facies have slightly elevated K2O and FeOT. Several analysis points within Shaler suggest the presence of feldspars, though these points have excess FeOT which suggests the presence of Fe oxide cement or inclusions. The majority of LIBS analyses have compositions which indicate that they are mixtures of pyroxene and feldspar. The Shaler feldspathic compositions are more alkaline than typical feldspars from shergottites, suggesting an alkaline basaltic source region, particularly for the K2O-enriched Facies 7. Apart from possible iron-oxide cement, there is little evidence for chemical alteration at Shaler, although calcium-sulfate veins comparable to those observed lower in the stratigraphic section are present. The

  18. The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests

    International Nuclear Information System (INIS)

    Wiens, Roger C.; Barraclough, Bruce; Barkley, Walter C.; Bender, Steve; Bernardin, John; Bultman, Nathan; Clanton, Robert C.; Clegg, Samuel; Delapp, Dorothea; Dingler, Robert; Enemark, Don; Flores, Mike; Hale, Thomas; Lanza, Nina; Lasue, Jeremie; Latino, Joseph; Little, Cynthia; Morrison, Leland; Nelson, Tony; Romero, Frank; Salazar, Steven; Stiglich, Ralph; Storms, Steven; Trujillo, Tanner; Ulibarri, Mike; Vaniman, David; Whitaker, Robert; Witt, James; Maurice, Sylvestre; Bouye, Marc; Cousin, Agnes; Cros, Alain; D'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Kouach, Driss; Lasue, Jeremie; Pares, Laurent; Poitrasson, Franck; Striebig, Nicolas; Thocaven, Jean-Jacques; Saccoccio, Muriel; Perez, Rene; Bell, James F. III; Hays, Charles; Blaney, Diana; DeFlores, Lauren; Elliott, Tom; Kan, Ed; Limonadi, Daniel; Lindensmith, Chris; Miller, Ed; Reiter, Joseph W.; Roberts, Tom; Simmonds, John J.; Warner, Noah; Blank, Jennifer; Bridges, Nathan; Cais, Phillippe; Clark, Benton; Cremers, David; Dyar, M. Darby; Fabre, Cecile; Herkenhoff, Ken; Kirkland, Laurel; Landis, David; Langevin, Yves; Lanza, Nina; Newsom, Horton; Ollila, Ann; LaRocca, Frank; Ott, Melanie; Mangold, Nicolas; Manhes, Gerard; Mauchien, Patrick; Blank, Jennifer; McKay, Christopher; Mooney, Joe; Provost, Cheryl; Morris, Richard V.; Sautter, Violaine; Sautter, Violaine; Waterbury, Rob; Wong-Swanson, Belinda; Barraclough, Bruce; Bender, Steve; Vaniman, David

    2012-01-01

    The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover Curiosity provides remote compositional information using the first laser-induced breakdown spectrometer (LIBS) on a planetary mission, and provides sample texture and morphology data using a remote micro-imager (RMI). Overall, ChemCam supports MSL with five capabilities: remote classification of rock and soil characteristics; quantitative elemental compositions including light elements like hydrogen and some elements to which LIBS is uniquely sensitive (e.g., Li, Be, Rb, Sr, Ba); remote removal of surface dust and depth profiling through surface coatings; context imaging; and passive spectroscopy over the 240-905 nm range. ChemCam is built in two sections: The mast unit, consisting of a laser, telescope, RMI, and associated electronics, resides on the rover's mast, and is described in a companion paper. ChemCam's body unit, which is mounted in the body of the rover, comprises an optical de-multiplexer, three spectrometers, detectors, their coolers, and associated electronics and data handling logic. Additional instrument components include a 6 m optical fiber which transfers the LIBS light from the telescope to the body unit, and a set of onboard calibration targets. ChemCam was integrated and tested at Los Alamos National Laboratory where it also underwent LIBS calibration with 69 geological standards prior to integration with the rover. Post-integration testing used coordinated mast and instrument commands, including LIBS line scans on rock targets during system-level thermal-vacuum tests. In this paper we describe the body unit, optical fiber, and calibration targets, and the assembly, testing, and verification of the instrument prior to launch. (authors)

  19. Numerical simulation for regional ozone concentrations: A case study by weather research and forecasting/chemistry (WRF/Chem) model

    Energy Technology Data Exchange (ETDEWEB)

    Habib Al Razi, Khandakar Md; Hiroshi, Moritomi [Environmental and Renewable Energy System, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu City, 501-1193 (Japan)

    2013-07-01

    The objective of this research is to better understand and predict the atmospheric concentration distribution of ozone and its precursor (in particular, within the Planetary Boundary Layer (Within 110 km to 12 km) over Kasaki City and the Greater Tokyo Area using fully coupled online WRF/Chem (Weather Research and Forecasting/Chemistry) model. In this research, a serious and continuous high ozone episode in the Greater Tokyo Area (GTA) during the summer of 14–18 August 2010 was investigated using the observation data. We analyzed the ozone and other trace gas concentrations, as well as the corresponding weather conditions in this high ozone episode by WRF/Chem model. The simulation results revealed that the analyzed episode was mainly caused by the impact of accumulation of pollution rich in ozone over the Greater Tokyo Area. WRF/Chem has shown relatively good performance in modeling of this continuous high ozone episode, the simulated and the observed concentrations of ozone, NOx and NO2 are basically in agreement at Kawasaki City, with best correlation coefficients of 0.87, 0.70 and 0.72 respectively. Moreover, the simulations of WRF/Chem with WRF preprocessing software (WPS) show a better agreement with meteorological observations such as surface winds and temperature profiles in the ground level of this area. As a result the surface ozone simulation performances have been enhanced in terms of the peak ozone and spatial patterns, whereas WRF/Chem has been succeeded to generate meteorological fields as well as ozone, NOx, NO2 and NO.

  20. Radiative effects of black carbon aerosols on Indian monsoon: a study using WRF-Chem model

    Science.gov (United States)

    Soni, Pramod; Tripathi, Sachchida Nand; Srivastava, Rajesh

    2018-04-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is utilized to examine the radiative effects of black carbon (BC) aerosols on the Indian monsoon, for the year 2010. Five ensemble simulations with different initial conditions (1st to 5th December, 2009) were performed and simulation results between 1st January, 2010 to 31st December, 2010 were used for analysis. Most of the BC which stays near the surface during the pre-monsoon season gets transported to higher altitudes with the northward migration of the Inter Tropical Convergence Zone (ITCZ) during the monsoon season. In both the seasons, strong negative SW anomalies are present at the surface along with positive anomalies in the atmosphere, which results in the surface cooling and lower tropospheric heating, respectively. During the pre-monsoon season, lower troposphere heating causes increased convection and enhanced meridional wind circulation, bringing moist air from Indian Ocean and Bay of Bengal to the North-East India, leading to increased rainfall there. However, during the monsoon season, along with cooling over the land regions, a warming over the Bay of Bengal is simulated. This differential heating results in an increased westerly moisture flux anomaly over central India, leading to increased rainfall over northern parts of India but decreased rainfall over southern parts. Decreased rainfall over southern India is also substantiated by the presence of increased evaporation over Bay of Bengal and decrease over land regions.

  1. Ultrafine particles from power plants: Evaluation of WRF-Chem simulations with airborne measurements

    Science.gov (United States)

    Forkel, Renate; Junkermann, Wolfgang

    2017-04-01

    Ultrafine particles (UFP, particles with a diameter risk to human health and have a potential effect on climate as their presence affects the number concentration of cloud condensation nuclei. Despite of the possibly hazardous effects no regulations exist for this size class of ambient air pollution particles. While ground based continuous measurements of UFP are performed in Germany at several sites (e.g. the German Ultrafine Aerosol Network GUAN, Birmili et al. 2016, doi:10.5194/essd-8-355-2016) information about the vertical distribution of UFP within the atmospheric boundary layer is only scarce. This gap has been closed during the last years by regional-scale airborne surveys for UFP concentrations and size distributions over Germany (Junkermann et al., 2016, doi: 10.3402/tellusb.v68.29250) and Australia (Junkermann and Hacker, 2015, doi: 10.3402/tellusb.v67.25308). Power stations and refineries have been identified as a major source of UFP in Germany with observed particle concentrations > 50000 particles cm-3 downwind of these elevated point sources. Nested WRF-Chem simulations with 2 km grid width for the innermost domain are performed with UFP emission source strengths derived from the measurements in order to study the advection and vertical exchange of UFP from power plants near the Czech and Polish border and their impact on planetary boundary layer particle patterns. The simulations are evaluated against the airborne observations and the downward mixing of the UFP from the elevated sources is studied.

  2. Modelling Poly-Aromatic Hydrocarbons "online" with the GEOS-Chem Europe and Asia regional models.

    Science.gov (United States)

    Ivatt, P.; Evans, M. J.

    2017-12-01

    Poly-Aromatic Hydrocarbons (PAHs) are carcinogens and so are restricted by international treaties. PAHs are mainly emitted into the atmosphere by domestic (heating and cooking), natural (forest fires burning), as well as some industrial processes (coke ovens). PAHs partition between the gas and particle phase (notably carbonaceous particles) based on their volatility. In recent years, interest has turned to the possible health effects of their oxidation products (both nitrogenated and oxygenated) as it has been suggested that these oxidation products may be even more carcinogenic than the parent PAHs. To increase our understanding of the processes controlling the regional concentrations of PAHs and their oxidation products an "online" PAH model has been developed within the GEOS-Chem framework. This provides for the representation of the coupled aerosol/gas phase chemistry of the parent PAH and its secondary oxidation products. Benzo[a]pyrene is used as an exemplar but the methodology is flexible and the approach can be used for any PAH species. Comparisons are made with observations and the sources of variability discussed.

  3. Handheld highly selective plasmonic chem/biosensor using engineered binding proteins for extreme conformational changes

    Science.gov (United States)

    Kosciolek, Derek J.; Sonar, Ajay; Lepak, Lori A.; Schnatz, Peter; Bendoym, Igor; Brown, Mia C.; Koder, Ronald L.; Crouse, David T.

    2017-08-01

    In this project we develop a handheld, portable, highly selective and sensitive chem/biosensor that has potential applications in both airborne and water-based environmental sensing. The device relies on a plasmonic chip of subwavelength-scale periodic gold rods engineered to resonate in the near infrared. The chip is functionalized with a novel class of proteins that exhibit large conformational changes upon binding to a specific target analyte. The subsequent change in local refractive index near the surface of the gold is one to two orders of magnitude greater than current conventional methods, which produces a readily measurable 5 to 10 percent difference in light transmission. This allows us to forgo traditional, bulky tabletop setups in favor of a compact form factor. Using commercially available optics to construct a transmission-based optical train, measured changes in bulk refractive index are presented here. While synthesis of binding protein efforts are focused on heme as analyte for proof of concept validation, the functionalized protein can be engineered to pair with a wide variety of analytes with minimal alterations to the plasmonic chip or device design. Such flexibility allows for this device to potentially meet the needs of first responders and health care professionals in a multitude of scenarios.

  4. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

    Science.gov (United States)

    Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kuś, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chun-Min; Chen, Yunqing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Benjamin; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adèle D.; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stück, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alán; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin

    2015-01-01

    A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.

  5. Source apportionment of atmospheric mercury pollution in China using the GEOS-Chem model.

    Science.gov (United States)

    Wang, Long; Wang, Shuxiao; Zhang, Lei; Wang, Yuxuan; Zhang, Yanxu; Nielsen, Chris; McElroy, Michael B; Hao, Jiming

    2014-07-01

    China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35-50% of THg concentration and 50-70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

    Science.gov (United States)

    Clegg, Samuel M.; Wiens, Roger C.; Anderson, Ryan; Forni, Olivier; Frydenvang, Jens; Lasue, Jeremie; Cousin, Agnes; Payre, Valerie; Boucher, Tommy; Dyar, M. Darby; McLennan, Scott M.; Morris, Richard V.; Graff, Trevor G.; Mertzman, Stanley A; Ehlmann, Bethany L.; Belgacem, Ines; Newsom, Horton E.; Clark, Ben C.; Melikechi, Noureddine; Mezzacappa, Alissa; McInroy, Rhonda E.; Martinez, Ronald; Gasda, Patrick J.; Gasnault, Olivier; Maurice, Sylvestre

    2017-01-01

    The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O), have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with a calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was significantly over-estimated by the previous model, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. The uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data.

  7. Operational on-line coupled chemical weather forecasts for Europe with WRF/Chem

    Science.gov (United States)

    Hirtl, Marcus; Mantovani, Simone; Krüger, Bernd C.; Flandorfer, Claudia; Langer, Matthias

    2014-05-01

    Air quality is a key element for the well-being and quality of life of European citizens. Air pollution measurements and modeling tools are essential for the assessment of air quality according to EU legislation. The responsibilities of ZAMG as the national weather service of Austria include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. Meteorology is simulated simultaneously with the emissions, turbulent mixing, transport, transformation, and fate of trace gases and aerosols. The emphasis of the application is on predicting pollutants over Austria. Two domains are used for the simulations: the mother domain covers Europe with a resolution of 12 km, the inner domain includes the alpine region with a horizontal resolution of 4 km; 45 model levels are used in the vertical direction. The model runs 2 times per day for a period of 72 hours and is initialized with ECMWF forecasts. On-line coupled models allow considering two-way interactions between different atmospheric processes including chemistry (both gases and aerosols), clouds, radiation, boundary layer, emissions, meteorology and climate. In the operational set-up direct-, indirect and semi-direct effects between meteorology and air chemistry are enabled. The model is running on the HPCF (High Performance Computing Facility) of the ZAMG. In the current set-up 1248 CPUs are used. As the simulations need a big amount of computing resources, a method to safe I/O-time was implemented. Every MPI task writes all its output into the shared memory filesystem of the compute nodes. Once the WRF/Chem integration is finished, all split NetCDF-files are merged and saved on the global file system. The merge-routine is based on parallel-NetCDF. With this method the model runs about 30% faster on the SGI

  8. Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

    Directory of Open Access Journals (Sweden)

    T. Sherwen

    2016-02-01

    Full Text Available We present a global simulation of tropospheric iodine chemistry within the GEOS-Chem chemical transport model. This includes organic and inorganic iodine sources, standard gas-phase iodine chemistry, and simplified higher iodine oxide (I2OX, X = 2, 3, 4 chemistry, photolysis, deposition, and parametrized heterogeneous reactions. In comparisons with recent iodine oxide (IO observations, the simulation shows an average bias of  ∼ +90 % with available surface observations in the marine boundary layer (outside of polar regions, and of  ∼ +73 % within the free troposphere (350 hPa  <  p  <  900 hPa over the eastern Pacific. Iodine emissions (3.8 Tg yr−1 are overwhelmingly dominated by the inorganic ocean source, with 76 % of this emission from hypoiodous acid (HOI. HOI is also found to be the dominant iodine species in terms of global tropospheric IY burden (contributing up to 70 %. The iodine chemistry leads to a significant global tropospheric O3 burden decrease (9.0 % compared to standard GEOS-Chem (v9-2. The iodine-driven OX loss rate1 (748 Tg OX yr−1 is due to photolysis of HOI (78 %, photolysis of OIO (21 %, and reaction between IO and BrO (1 %. Increases in global mean OH concentrations (1.8 % by increased conversion of hydroperoxy radicals exceeds the decrease in OH primary production from the reduced O3 concentration. We perform sensitivity studies on a range of parameters and conclude that the simulation is sensitive to choices in parametrization of heterogeneous uptake, ocean surface iodide, and I2OX (X = 2, 3, 4 photolysis. The new iodine chemistry combines with previously implemented bromine chemistry to yield a total bromine- and iodine-driven tropospheric O3 burden decrease of 14.4 % compared to a simulation without iodine and bromine chemistry in the model, and a small increase in OH (1.8 %. This is a significant impact and so halogen chemistry needs to be

  9. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    International Nuclear Information System (INIS)

    Kuchynka, D.

    1995-01-01

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products

  10. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuchynka, D.

    1995-12-31

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products.

  11. Global impacts of tropospheric halogens (Cl, Br, I on oxidants and composition in GEOS-Chem

    Directory of Open Access Journals (Sweden)

    T. Sherwen

    2016-09-01

    Full Text Available We present a simulation of the global present-day composition of the troposphere which includes the chemistry of halogens (Cl, Br, I. Building on previous work within the GEOS-Chem model we include emissions of inorganic iodine from the oceans, anthropogenic and biogenic sources of halogenated gases, gas phase chemistry, and a parameterised approach to heterogeneous halogen chemistry. Consistent with Schmidt et al. (2016 we do not include sea-salt debromination. Observations of halogen radicals (BrO, IO are sparse but the model has some skill in reproducing these. Modelled IO shows both high and low biases when compared to different datasets, but BrO concentrations appear to be modelled low. Comparisons to the very sparse observations dataset of reactive Cl species suggest the model represents a lower limit of the impacts of these species, likely due to underestimates in emissions and therefore burdens. Inclusion of Cl, Br, and I results in a general improvement in simulation of ozone (O3 concentrations, except in polar regions where the model now underestimates O3 concentrations. Halogen chemistry reduces the global tropospheric O3 burden by 18.6 %, with the O3 lifetime reducing from 26 to 22 days. Global mean OH concentrations of 1.28  ×  106 molecules cm−3 are 8.2 % lower than in a simulation without halogens, leading to an increase in the CH4 lifetime (10.8 % due to OH oxidation from 7.47 to 8.28 years. Oxidation of CH4 by Cl is small (∼  2 % but Cl oxidation of other VOCs (ethane, acetone, and propane can be significant (∼  15–27 %. Oxidation of VOCs by Br is smaller, representing 3.9 % of the loss of acetaldehyde and 0.9 % of the loss of formaldehyde.

  12. Development and Performance of the Modularized, High-performance Computing and Hybrid-architecture Capable GEOS-Chem Chemical Transport Model

    Science.gov (United States)

    Long, M. S.; Yantosca, R.; Nielsen, J.; Linford, J. C.; Keller, C. A.; Payer Sulprizio, M.; Jacob, D. J.

    2014-12-01

    The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been reengineered to serve as a platform for a range of computational atmospheric chemistry science foci and applications. Development included modularization for coupling to general circulation and Earth system models (ESMs) and the adoption of co-processor capable atmospheric chemistry solvers. This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of GEOS-Chem scientific code to permit seamless transition from the GEOS-Chem stand-alone serial CTM to deployment as a coupled ESM module. In this manner, the continual stream of updates contributed by the CTM user community is automatically available for broader applications, which remain state-of-science and directly referenceable to the latest version of the standard GEOS-Chem CTM. These developments are now available as part of the standard version of the GEOS-Chem CTM. The system has been implemented as an atmospheric chemistry module within the NASA GEOS-5 ESM. The coupled GEOS-5/GEOS-Chem system was tested for weak and strong scalability and performance with a tropospheric oxidant-aerosol simulation. Results confirm that the GEOS-Chem chemical operator scales efficiently for any number of processes. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemical operator means that the relative cost goes down with increasing number of processes, making fine-scale resolution simulations possible.

  13. CHEM2D-OPP: A new linearized gas-phase ozone photochemistry parameterization for high-altitude NWP and climate models

    Directory of Open Access Journals (Sweden)

    J. P. McCormack

    2006-01-01

    Full Text Available The new CHEM2D-Ozone Photochemistry Parameterization (CHEM2D-OPP for high-altitude numerical weather prediction (NWP systems and climate models specifies the net ozone photochemical tendency and its sensitivity to changes in ozone mixing ratio, temperature and overhead ozone column based on calculations from the CHEM2D interactive middle atmospheric photochemical transport model. We evaluate CHEM2D-OPP performance using both short-term (6-day and long-term (1-year stratospheric ozone simulations with the prototype high-altitude NOGAPS-ALPHA forecast model. An inter-comparison of NOGAPS-ALPHA 6-day ozone hindcasts for 7 February 2005 with ozone photochemistry parameterizations currently used in operational NWP systems shows that CHEM2D-OPP yields the best overall agreement with both individual Aura Microwave Limb Sounder ozone profile measurements and independent hemispheric (10°–90° N ozone analysis fields. A 1-year free-running NOGAPS-ALPHA simulation using CHEM2D-OPP produces a realistic seasonal cycle in zonal mean ozone throughout the stratosphere. We find that the combination of a model cold temperature bias at high latitudes in winter and a warm bias in the CHEM2D-OPP temperature climatology can degrade the performance of the linearized ozone photochemistry parameterization over seasonal time scales despite the fact that the parameterized temperature dependence is weak in these regions.

  14. E-chem page: A Support System for Remote Diagnosis of Water Quality in Boiling Water Reactors

    International Nuclear Information System (INIS)

    Naohiro Kusumi; Takayasu Kasahara; Kazuhiko Akamine; Kenji Tada; Naoshi Usui; Nobuyuki Oota

    2002-01-01

    It is important to control and maintain water quality for nuclear power plants. Chemical engineers sample and monitor reactor water from various subsystems and analyze the chemical quality as routine operations. With regard to controlling water quality, new technologies have been developed and introduced to improve the water quality from both operation and material viewpoints. To maintain the quality, it is important to support chemical engineers in evaluating the water quality and realizing effective retrieval of stored data and documents. We have developed a remote support system using the Internet to diagnose BWR water quality, which we call e-chem page. The e-chem page integrates distributed data and information in a Web server, and makes it easy to evaluate the data on BWR water chemistry. This system is composed of four functions: data transmission, water quality evaluation, inquiry and history retrieval system, and reference to documents on BWR water chemistry. The developed system is now being evaluated in trial operations by Hitachi, Ltd. and an electric power company. In addition diagnosis technology applying independent component analysis (ICA) is being developed to improve predictive capability of the system. This paper describes the structure and function of the e-chem page and presents results of obtained with the proposed system for the prediction of chemistry conditions in reactor water. (authors)

  15. Air Quality Modeling for the Urban Jackson, Mississippi Region Using a High Resolution WRF/Chem Model

    Directory of Open Access Journals (Sweden)

    Shelton J. Swanier

    2011-06-01

    Full Text Available In this study, an attempt was made to simulate the air quality with reference to ozone over the Jackson (Mississippi region using an online WRF/Chem (Weather Research and Forecasting–Chemistry model. The WRF/Chem model has the advantages of the integration of the meteorological and chemistry modules with the same computational grid and same physical parameterizations and includes the feedback between the atmospheric chemistry and physical processes. The model was designed to have three nested domains with the inner-most domain covering the study region with a resolution of 1 km. The model was integrated for 48 hours continuously starting from 0000 UTC of 6 June 2006 and the evolution of surface ozone and other precursor pollutants were analyzed. The model simulated atmospheric flow fields and distributions of NO2 and O3 were evaluated for each of the three different time periods. The GIS based spatial distribution maps for ozone, its precursors NO, NO2, CO and HONO and the back trajectories indicate that all the mobile sources in Jackson, Ridgeland and Madison contributing significantly for their formation. The present study demonstrates the applicability of WRF/Chem model to generate quantitative information at high spatial and temporal resolution for the development of decision support systems for air quality regulatory agencies and health administrators.

  16. PubChemQC Project: A Large-Scale First-Principles Electronic Structure Database for Data-Driven Chemistry.

    Science.gov (United States)

    Nakata, Maho; Shimazaki, Tomomi

    2017-06-26

    Large-scale molecular databases play an essential role in the investigation of various subjects such as the development of organic materials, in silico drug design, and data-driven studies with machine learning. We have developed a large-scale quantum chemistry database based on first-principles methods. Our database currently contains the ground-state electronic structures of 3 million molecules based on density functional theory (DFT) at the B3LYP/6-31G* level, and we successively calculated 10 low-lying excited states of over 2 million molecules via time-dependent DFT with the B3LYP functional and the 6-31+G* basis set. To select the molecules calculated in our project, we referred to the PubChem Project, which was used as the source of the molecular structures in short strings using the InChI and SMILES representations. Accordingly, we have named our quantum chemistry database project "PubChemQC" ( http://pubchemqc.riken.jp/ ) and placed it in the public domain. In this paper, we show the fundamental features of the PubChemQC database and discuss the techniques used to construct the data set for large-scale quantum chemistry calculations. We also present a machine learning approach to predict the electronic structure of molecules as an example to demonstrate the suitability of the large-scale quantum chemistry database.

  17. Inclusion of ash and SO2 emissions from volcanic eruptions in WRF-Chem: development and some applications

    Directory of Open Access Journals (Sweden)

    M. Stuefer

    2013-04-01

    Full Text Available We describe a new functionality within the Weather Research and Forecasting (WRF model with coupled Chemistry (WRF-Chem that allows simulating emission, transport, dispersion, transformation and sedimentation of pollutants released during volcanic activities. Emissions from both an explosive eruption case and a relatively calm degassing situation are considered using the most recent volcanic emission databases. A preprocessor tool provides emission fields and additional information needed to establish the initial three-dimensional cloud umbrella/vertical distribution within the transport model grid, as well as the timing and duration of an eruption. From this source condition, the transport, dispersion and sedimentation of the ash cloud can be realistically simulated by WRF-Chem using its own dynamics and physical parameterization as well as data assimilation. Examples of model applications include a comparison of tephra fall deposits from the 1989 eruption of Mount Redoubt (Alaska and the dispersion of ash from the 2010 Eyjafjallajökull eruption in Iceland. Both model applications show good coincidence between WRF-Chem and observations.

  18. Calibration of the Fluorine, Chlorine and Hydrogen Content of Apatites With the ChemCam LIBS Instrument

    Science.gov (United States)

    Meslin, P.-Y.; Cicutto, L.; Forni, O.; Drouet, C.; Rapin, W.; Nachon, M.; Cousin, A.; Blank, J. G.; McCubbin, F. M.; Gasnault, O.; hide

    2016-01-01

    Determining the composition of apatites is important to understand the behavior of volatiles during planetary differentiation. Apatite is an ubiquitous magmatic mineral in the SNC meteorites. It is a significant reservoir of halogens in these meteorites and has been used to estimate the halogen budget of Mars. Apatites have been identified in sandstones and pebbles at Gale crater by ChemCam, a Laser-Induced Breakdown Spectroscometer (LIBS) instrument onboard the Curiosity rover. Their presence was inferred from correlations between calcium, fluorine (using the CaF molecular band centered near 603 nm, whose detection limit is much lower that atomic or ionic lines and, in some cases, phosphorus (whose detection limit is much larger). An initial quantification of fluorine, based on fluorite (CaF2)/basalt mixtures and obtained at the LANL laboratory, indicated that the excess of F/Ca (compared to the stoichiometry of pure fluorapatites) found on Mars in some cases could be explained by the presence of fluorite. Chlorine was not detected in these targets, at least above a detection limit of 0.6 wt% estimated from. Fluorapatite was later also detected by X-ray diffraction (with CheMin) at a level of approx.1wt% in the Windjana drill sample (Kimberley area), and several points analyzed by ChemCam in this area also revealed a correlation between Ca and F. The in situ detection of F-rich, Cl-poor apatites contrasts with the Cl-rich, F-poor compositions of apatites found in basaltic shergottites and in gabbroic clasts from the martian meteorite NWA 7034, which were also found to be more Cl-rich than apatites from basalts on Earth, the Moon, or Vesta. The in situ observations could call into question one of the few possible explanations brought forward to explain the SNC results, namely that Mars may be highly depleted in fluorine. The purpose of the present study is to refine the calibration of the F, Cl, OH and P signals measured by the ChemCam LIBS instrument, initiated

  19. Modelling the urban air quality in Hamburg with the new city-scale chemistry transport model CityChem

    Science.gov (United States)

    Karl, Matthias; Ramacher, Martin; Aulinger, Armin; Matthias, Volker; Quante, Markus

    2017-04-01

    Air quality modelling plays an important role by providing guidelines for efficient air pollution abatement measures. Currently, most urban dispersion models treat air pollutants as passive tracer substances or use highly simplified chemistry when simulating air pollutant concentrations on the city-scale. The newly developed urban chemistry-transport model CityChem has the capability of modelling the photochemical transformation of multiple pollutants along with atmospheric diffusion to produce pollutant concentration fields for the entire city on a horizontal resolution of 100 m or even finer and a vertical resolution of 24 layers up to 4000 m height. CityChem is based on the Eulerian urban dispersion model EPISODE of the Norwegian Institute for Air Research (NILU). CityChem treats the complex photochemistry in cities using detailed EMEP chemistry on an Eulerian 3-D grid, while using simple photo-stationary equilibrium on a much higher resolution grid (receptor grid), i.e. close to industrial point sources and traffic sources. The CityChem model takes into account that long-range transport contributes to urban pollutant concentrations. This is done by using 3-D boundary concentrations for the city domain derived from chemistry-transport simulations with the regional air quality model CMAQ. For the study of the air quality in Hamburg, CityChem was set-up with a main grid of 30×30 grid cells of 1×1 km2 each and a receptor grid of 300×300 grid cells of 100×100 m2. The CityChem model was driven with meteorological data generated by the prognostic meteorology component of the Australian chemistry-transport model TAPM. Bottom-up inventories of emissions from traffic, industry, households were based on data of the municipality of Hamburg. Shipping emissions for the port of Hamburg were taken from the Clean North Sea Shipping project. Episodes with elevated ozone (O3) were of specific interest for this study, as these are associated with exceedances of the World

  20. A Case Study in Competitive Technical and Market Intelligence Support and Lessons Learned for the uChemLab LDRD Grand Challenge Project; TOPICAL

    International Nuclear Information System (INIS)

    SOUTHWELL, EDWIN T.; GARCIA, MARIE L.; MEYERS, CHARLES E.

    2001-01-01

    The(mu)ChemLab(trademark) Laboratory Directed Research and Development (LDRD) Grand Challenge project began in October 1996 and ended in September 2000. The technical managers of the(mu)ChemLab(trademark) project and the LDRD office, with the support of a consultant, conducted a competitive technical and market demand intelligence analysis of the(mu)ChemLab(trademark). The managers used this knowledge to make project decisions and course adjustments. CTI/MDI positively impacted the project's technology development, uncovered potential technology partnerships, and supported eventual industry partner contacts. CTI/MDI analysis is now seen as due diligence and the(mu)ChemLab(trademark) project is now the model for other Sandia LDRD Grand Challenge undertakings. This document describes the CTI/MDI analysis and captures the more important ''lessons learned'' of this Grand Challenge project, as reported by the project's management team

  1. Rozhovor s Jiřím Poláchem a Michaelou Záluskou z Knihovny ÚOCHB

    Czech Academy of Sciences Publication Activity Database

    Burešová, Iva

    2-3 (2016) E-ISSN 1805-2800 Keywords : interview * Institute of Organic Chemistry and Biochemistry of the CAS * library tramformation * chemLib https://www.lib.cas.cz/casopis-informace/knihovna-uochb/

  2. Development of a Grid-Independent Geos-Chem Chemical Transport Model (v9-02) as an Atmospheric Chemistry Module for Earth System Models

    Science.gov (United States)

    Long, M. S.; Yantosca, R.; Nielsen, J. E; Keller, C. A.; Da Silva, A.; Sulprizio, M. P.; Pawson, S.; Jacob, D. J.

    2015-01-01

    The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been re-engineered to also serve as an atmospheric chemistry module for Earth system models (ESMs). This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of the GEOSChem scientific code, permitting the exact same GEOSChem code to be used as an ESM module or as a standalone CTM. In this manner, the continual stream of updates contributed by the CTM user community is automatically passed on to the ESM module, which remains state of science and referenced to the latest version of the standard GEOS-Chem CTM. A major step in this re-engineering was to make GEOS-Chem grid independent, i.e., capable of using any geophysical grid specified at run time. GEOS-Chem data sockets were also created for communication between modules and with external ESM code. The grid-independent, ESMF-compatible GEOS-Chem is now the standard version of the GEOS-Chem CTM. It has been implemented as an atmospheric chemistry module into the NASA GEOS- 5 ESM. The coupled GEOS-5-GEOS-Chem system was tested for scalability and performance with a tropospheric oxidant-aerosol simulation (120 coupled species, 66 transported tracers) using 48-240 cores and message-passing interface (MPI) distributed-memory parallelization. Numerical experiments demonstrate that the GEOS-Chem chemistry module scales efficiently for the number of cores tested, with no degradation as the number of cores increases. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemistry module means that the relative cost goes down with increasing number of cores in a massively parallel environment.

  3. Application of WRF/Chem over East Asia: Part I. Model evaluation and intercomparison with MM5/CMAQ

    Science.gov (United States)

    Zhang, Yang; Zhang, Xin; Wang, Litao; Zhang, Qiang; Duan, Fengkui; He, Kebin

    2016-01-01

    In this work, the application of the online-coupled Weather Research and Forecasting model with chemistry (WRF/Chem) version 3.3.1 is evaluated over East Asia for January, April, July, and October 2005 and compared with results from a previous application of an offline model system, i.e., the Mesoscale Model and Community Multiple Air Quality modeling system (MM5/CMAQ). The evaluation of WRF/Chem is performed using multiple observational datasets from satellites and surface networks in mainland China, Hong Kong, Taiwan, and Japan. WRF/Chem simulates well specific humidity (Q2) and downward longwave and shortwave radiation (GLW and GSW) with normalized mean biases (NMBs) within 24%, but shows moderate to large biases for temperature at 2-m (T2) (NMBs of -9.8% to 75.6%) and precipitation (NMBs of 11.4-92.7%) for some months, and wind speed at 10-m (WS10) (NMBs of 66.5-101%), for all months, indicating some limitations in the YSU planetary boundary layer scheme, the Purdue Lin cloud microphysics, and the Grell-Devenyi ensemble scheme. WRF/Chem can simulate the column abundances of gases reasonably well with NMBs within 30% for most months but moderately to significantly underpredicts the surface concentrations of major species at all sites in nearly all months with NMBs of -72% to -53.8% for CO, -99.4% to -61.7% for NOx, -84.2% to -44.5% for SO2, -63.9% to -25.2% for PM2.5, and -68.9% to 33.3% for PM10, and aerosol optical depth in all months except for October with NMBs of -38.7% to -16.2%. The model significantly overpredicts surface concentrations of O3 at most sites in nearly all months with NMBs of up to 160.3% and NO3- at the Tsinghua site in all months. Possible reasons for large underpredictions include underestimations in the anthropogenic emissions of CO, SO2, and primary aerosol, inappropriate vertical distributions of emissions of SO2 and NO2, uncertainties in upper boundary conditions (e.g., for O3 and CO), missing or inaccurate model representations (e

  4. ODM2 (Observation Data Model): The EarthChem Use Case

    Science.gov (United States)

    Lehnert, Kerstin; Song, Lulin; Hsu, Leslie; Horsburgh, Jeffrey S.; Aufdenkampe, Anthony K.; Mayorga, Emilio; Tarboton, David; Zaslavsky, Ilya

    2014-05-01

    PetDB is an online data system that was created in the late 1990's to serve online a synthesis of published geochemical and petrological data of igneous and metamorphic rocks. PetDB has today reached a volume of 2.5 million analytical values for nearly 70,000 rock samples. PetDB's data model (Lehnert et al., G-Cubed 2000) was designed to store sample-based observational data generated by the analysis of rocks, together with a wide range of metadata documenting provenance of the samples, analytical procedures, data quality, and data source. Attempts to store additional types of geochemical data such as time-series data of seafloor hydrothermal springs and volcanic gases, depth-series data for marine sediments and soils, and mineral or mineral inclusion data revealed the limitations of the schema: the inability to properly record sample hierarchies (for example, a garnet that is included in a diamond that is included in a xenolith that is included in a kimberlite rock sample), inability to properly store time-series data, inability to accommodate classification schemes other than rock lithologies, deficiencies of identifying and documenting datasets that are not part of publications. In order to overcome these deficiencies, PetDB has been developing a new data schema using the ODM2 information model (ODM=Observation Data Model). The development of ODM2 is a collaborative project that leverages the experience of several existing information representations, including PetDB and EarthChem, and the CUAHSI HIS Observations Data Model (ODM), as well as the general specification for encoding observational data called Observations and Measurements (O&M) to develop a uniform information model that seamlessly manages spatially discrete, feature-based earth observations from environmental samples and sample fractions as well as in-situ sensors, and to test its initial implementation in a variety of user scenarios. The O&M model, adopted as an international standard by the Open

  5. Lightning NOx emissions over the USA constrained by TES ozone observations and the GEOS-Chem model

    Science.gov (United States)

    Jourdain, L.; Kulawik, S. S.; Worden, H. M.; Pickering, K. E.; Worden, J.; Thompson, A. M.

    2010-01-01

    Improved estimates of NOx from lightning sources are required to understand tropospheric NOx and ozone distributions, the oxidising capacity of the troposphere and corresponding feedbacks between chemistry and climate change. In this paper, we report new satellite ozone observations from the Tropospheric Emission Spectrometer (TES) instrument that can be used to test and constrain the parameterization of the lightning source of NOx in global models. Using the National Lightning Detection (NLDN) and the Long Range Lightning Detection Network (LRLDN) data as well as the HYPSLIT transport and dispersion model, we show that TES provides direct observations of ozone enhanced layers downwind of convective events over the USA in July 2006. We find that the GEOS-Chem global chemistry-transport model with a parameterization based on cloud top height, scaled regionally and monthly to OTD/LIS (Optical Transient Detector/Lightning Imaging Sensor) climatology, captures the ozone enhancements seen by TES. We show that the model's ability to reproduce the location of the enhancements is due to the fact that this model reproduces the pattern of the convective events occurrence on a daily basis during the summer of 2006 over the USA, even though it does not well represent the relative distribution of lightning intensities. However, this model with a value of 6 Tg N/yr for the lightning source (i.e.: with a mean production of 260 moles NO/Flash over the USA in summer) underestimates the intensities of the ozone enhancements seen by TES. By imposing a production of 520 moles NO/Flash for lightning occurring in midlatitudes, which better agrees with the values proposed by the most recent studies, we decrease the bias between TES and GEOS-Chem ozone over the USA in July 2006 by 40%. However, our conclusion on the strength of the lightning source of NOx is limited by the fact that the contribution from the stratosphere is underestimated in the GEOS-Chem simulations.

  6. Simulations of the Holuhraun eruption 2014 with WRF-Chem and evaluation with satellite and ground based SO2 measurements

    Science.gov (United States)

    Hirtl, Marcus; Arnold-Arias, Delia; Flandorfer, Claudia; Maurer, Christian; Mantovani, Simone; Natali, Stefano

    2016-04-01

    Volcanic eruptions, with gas or/and particle emissions, directly influence our environment, with special significance when they either occur near inhabited regions or are transported towards them. In addition to the well-known affectation of air traffic, with large economic impacts, the ground touching plumes can lead directly to an influence of soil, water and even to a decrease of air quality. The eruption of Holuhraun in August 2014 in central Iceland is the country's largest lava and gas eruption since the Lakagígar eruption in 1783. Nevertheless, very little volcanic ash was produced. The main atmospheric threat from this event was the SO2 pollution that frequently violated the Icelandic National Air Quality Standards in many population centers. However, the SO2 affectation was not limited to Iceland but extended to mainland Europe. The on-line coupled model WRF-Chem is used to simulate the dispersion of SO2 for this event that affected the central European regions. The volcanic emissions are considered in addition to the anthropogenic and biogenic ground sources at European scale. A modified version of WRF-Chem version 4.1 is used in order to use time depending injection heights and mass fluxes which were obtained from in situ observations. WRF-Chem uses complex gas- (RADM2) and aerosol- (MADE-SORGAM) chemistry and is operated on a European domain (12 km resolution), and a nested grid covering the Alpine region (4 km resolution). The study is showing the evaluation of the model simulations with satellite and ground based measurement data of SO2. The analysis is conducted on a data management platform, which is currently developed in the frame of the ESA-funded project TAMP "Technology and Atmospheric Mission Platform": it provides comprehensive functionalities to visualize and numerically compare data from different sources (model, satellite and ground-measurements).

  7. The ChemScreen project to design a pragmatic alternative approach to predict reproductive toxicity of chemicals

    DEFF Research Database (Denmark)

    van der Burg, Bart; Wedebye, Eva Bay; Dietrich, Daniel R.

    2015-01-01

    to validate the test panel using mechanistic approaches. We are actively engaged in promoting regulatory acceptance of the tools developed as an essential step towards practical application, including case studies for read-across purposes. With this approach, a significant saving in animal use and associated......There is a great need for rapid testing strategies for reproductive toxicity testing, avoiding animal use. The EU Framework program 7 project ChemScreen aimed to fill this gap in a pragmatic manner preferably using validated existing tools and place them in an innovative alternative testing...

  8. ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars

    Science.gov (United States)

    Maurice, Sylvestre; Clegg, Samuel M.; Wiens, Roger C.; Gasnault, O.; Rapin, W.; Forni, O.; Cousin, Agnes; Sautter, V.; Mangold, Nicolas; Le Deit, L.; Nachon, Marion; Anderson, Ryan; Lanza, Nina; Fabre, Cecile; Payre, Valerie; Lasue, Jeremie; Meslin, Pierre-Yves; LeVeille, Richard A.; Barraclough, Bruce; Beck, Pierre; Bender, Steven C.; Berger, Gilles; Bridges, John C.; Bridges, Nathan; Dromert, Gilles; Dyar, M. Darby; Francis, Raymond; Frydenvang, Jens; Gondet, B.; Ehlmann, Bethany L.; Herkenhoff, Kenneth E.; Johnson, Jeffrey R.; Langevin, Yves; Madsen Morten B.,; Melikechi, N.; Lacour, J.-L.; Le Mouelic, Stephane; Lewin, Eric; Newsom, Horton E.; Ollila, Ann M.; Pinet, Patrick; Schroder, S.; Sirven, Jean-Baptiste; Tokar, Robert L.; Toplis, M.J.; d'Uston, Claude; Vaniman, David; Vasavada, Ashwin R.

    2016-01-01

    At Gale crater, Mars, ChemCam acquired its first laser-induced breakdown spectroscopy (LIBS) target on Sol 13 of the landed portion of the mission (a Sol is a Mars day). Up to Sol 800, more than 188000 LIBS spectra were acquired on more than 5800 points distributed over about 650 individual targets. We present a comprehensive review of ChemCam scientific accomplishments during that period, together with a focus on the lessons learned from the first use of LIBS in space. For data processing, we describe new tools that had to be developed to account for the uniqueness of Mars data. With regard to chemistry, we present a summary of the composition range measured on Mars for major-element oxides (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O) based on various multivariate models, with associated precisions. ChemCam also observed H, and the non-metallic elements C, O, P, and S, which are usually difficult to quantify with LIBS. F and Cl are observed through their molecular lines. We discuss the most relevant LIBS lines for detection of minor and trace elements (Li, Rb, Sr, Ba, Cr, Mn, Ni, and Zn). These results were obtained thanks to comprehensive ground reference datasets, which are set to mimic the expected mineralogy and chemistry on Mars. With regard to the first use of LIBS in space, we analyze and quantify, often for the first time, each of the advantages of using stand-off LIBS in space: no sample preparation, analysis within its petrological context, dust removal, sub-millimeter scale investigation, multi-point analysis, the ability to carry out statistical surveys and whole-rock analyses, and rapid data acquisition. We conclude with a discussion of ChemCam performance to survey the geochemistry of Mars, and its valuable support of decisions about selecting where and whether to make observations with more time and resource-intensive tools in the rover's instrument suite. In the end, we present a bird's-eye view of the many scientific results: discovery of felsic

  9. ChemCam at Gale Crater: Highlights and Discoveries from Three Years of Chemical Measurements on Mars

    Science.gov (United States)

    Blaney, Diana L.; Wiens, Roger; Maurice, Sylvestre; Gasnault, Olivier; Anderson, Ryan; Bridges, John; Bridges, Nathan; Clegg, Samuel; Clark, Benton; Ehlmann, Bethany; Dyar, Melinda D.; Fisk, Martin; Francis, Raymond; Fabre, Cecile; Forni, Olivier; Frydenvang, Jens; Johnson, Jeffery; Lanza, Nina; Leveille, Richard; Lasue, Jeremie; Le Deit, Laetitia; Mangold, Nicholas; Melikechi, Noureddine; Nachon, Marion; Newsom, Horton; Payre, Valerie; Rapin, William; Sautter, Violane; Vaniman, David; Grotzinger, John; Vasavad, Ashwin; Crisp, Joy

    2015-11-01

    ChemCam has undertaken a detailed chemical investigation of the rocks and soils at Gale crater over the last three years with over six thousand separate geochemical measurements. Recent recalibration of the ChemCam data using a new library of >350 geochemical standards has enabled increased elemental accuracies over a wider compositional range. The increased accuracy combined with ChemCam’s small spot size allows for the chemistry of mineral end members including feldspars, high silica, oxide rich grains to be identified. ChemCam has observed both sedimentary and igneous compositions. Igneous compositions are generally present in conglomerates and in float rocks. Compositions show a wide range of igneous chemistry ranging from basaltic to feldspar rich assemblages.Sedimentary rocks have a wide range of compositions reflecting both differences in chemical source regions and in depositional and diagenetic histories. The “Sheepbed” mudstones cluster around Martian average crustal compositions. The “Kimberley” outcrop showed enhanced potassium reaching concentrations up to ~6 wt% K2O. More recent observations in the Murray Formation at the base of Mt. Sharp reveal mudstones that are lower in magnesium and higher in silica and aluminum than the more basaltic mudstones previously investigated. Extremely high silica (75-85 wt%) deposits have also been identified. The high silica observations were associated with increased TiO2, While the Murray mudstones are generally low in magnesium, local enhancements in magnesium have also been noted associated with resistant facies in the outcrop. Chemical trends also indicate that iron oxide phases may also be present as cements. Sandstone facies with a mafic composition are also present. Veins in the unit also show a wide range of compositions indicating fluid chemistries rich in calcium sulfate, fluorine, magnesium and iron were present. Vein chemistry could be the result of distinct fluids migrating through from a

  10. Reply to the 'Comment on "Revisiting the definition of local hardness and hardness kernel"' by C. Morell, F. Guégan, W. Lamine, and H. Chermette, Phys. Chem. Chem. Phys., 2018, 20, DOI.

    Science.gov (United States)

    Franco-Pérez, Marco; Polanco-Ramírez, Carlos A; Gázquez, José L; Ayers, Paul W

    2018-03-28

    This reply complements the comment of Guégan et al. about our recent work on the revision of the local hardness and the hardness kernel concepts. Guegan et al. analyze our work using a Taylor series expansion of the energy as a functional of the electron density, to show that our procedure opens a new way to define local descriptors. In this contribution we show that the strategy we followed for the local hardness and the hardness kernel is even more general, and that it can be used to derive from a global response function its corresponding local and non-local counterparts by: (1) requiring that the integral over one of the two variables that characterizes the non-local function leads to the local function, and that the integral over the local function leads to the global response index, and (2) assuming that the global and local functions are related through the electronic density, by making use of the chain rule for functional derivatives.

  11. A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

    Energy Technology Data Exchange (ETDEWEB)

    Michalewicz, M.T. [CSIRO, Supercomputing Support Group, Carlton, VIC (Australia). Division of Information Technology; Winkler, D.A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC (Australia). Div. of Chemical Physics; Brunger, M.J.; McCarthy, L.E. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences; Von Niessen, W. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences

    1996-09-01

    The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C{sub 4}H{sub 6}) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green`s function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C{sub 4}H{sub 6}. A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene`s chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs.

  12. Theoretical modeling and analysis of the emission spectra of a ChemCam standard: Basalt BIR-1A

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Judge, E.J. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johns, H.M.; Kilcrease, D.P. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, J.E. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); McInroy, R. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wiens, R.C. [Space and Remote Sensing Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, S.M. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-08-01

    We report on efforts to perform theoretical modeling of the emission spectrum measured from a basalt sample. We compare our calculations with measurements that were made to provide standards for the ChemCam instrument on the Mars Science Laboratory. We find that to obtain good agreement between modeling and the measurement, it is necessary to determine atomic and ionic level populations via a multi-element approach in which the free electron density that is created influences all the species within the plasma. Calculations that consider each element separately are found to be in poorer agreement with the measured spectrum, indicating that the ‘matrix effect’ term often used to describe the influence of other species on the emission spectrum from a given element is due to the influence of the global electron density of the plasma. We explore the emission features in both the visible and near-infrared wavelength ranges, and also examine radiation transport effects for some of the most intense features found in the basalt spectrum. Finally, we also provide comparisons of the ChemCam measurement with new high-resolution spectral measurements. - Highlights: • LIBS basalt spectrum • Ab-initio theoretical modeling • Discussion of matrix effects • Discussion of radiation transport effects • High-resolution measurements of Basalt.

  13. A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

    International Nuclear Information System (INIS)

    Michalewicz, M.T.; Winkler, D.A.; Brunger, M.J.; McCarthy, L.E.; Von Niessen, W.

    1996-09-01

    The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C 4 H 6 ) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green's function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C 4 H 6 . A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene's chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs

  14. Corrigendum to "Destruction of amphetamine in aqueous solution using gamma irradiation" [Radiat. Phys. Chem. 139 (2017) 17-21

    Science.gov (United States)

    Alkhuraiji, Turki S.; Ajlouni, Abdul-Wali; Alotaibi, Noura A.

    2018-04-01

    The authors regret to have omitted to add a co-author in the author list of this research article. They would like to add the following author who has contributed to the article: Noura A. Alotaibi, King Fahad Medical City, Riyadh, Saudi Arabia.

  15. Publisher's Note: "Thermally driven molecular linear motors: A molecular dynamics study" [J. Chem. Phys. 131, 241104 (2009)

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

    2010-01-01

    This article was originally published online on 29 December 2009 with an incorrect journal title in Ref. 22; the correct journal title should have been “Small.” AIP apologizes for this error. All online versions of the article were corrected on 5 January 2010; the article was correct as it appear...

  16. Estimation of aerosol water and chemical composition from AERONET at Cabauw, the Netherlands, Atmos. Chem. Phys. Discuss., 13, ,

    NARCIS (Netherlands)

    Beelen, A.J. van; Roelofs, G.J.H.; Hasekamp, O.P.; Henzing, J.S.; Röckmann, T.

    2013-01-01

    This study is of our particular interest as the quality of our chemical transport model Lotos-Euros can be improved by our understanding of the aerosol-light interaction. In this study we derive aerosol water and chemical composition by a modeling approach that combines in situ measured and remotely

  17. ChemSkill Builder 2000, Version 6.1 [CD-ROM] (by James D. Spain and Harold J. Peters)

    Science.gov (United States)

    Keeney-Kennicutt, Reviewed By Wendy L.

    2000-07-01

    One of the major challenges for faculty teaching general chemistry is how to encourage students to practice solving problems. We know that for students to develop chemical intuition and problem-solving skills, they must "get their hands dirty" as they decipher and unravel problems inherent to our discipline. One tool that I've used since its release in 1996 is the ChemSkill Builder, an electronic homework package. The latest version, ChemSkill Builder (CSB) 2000, version 6.1, is an excellent, effective integration of teaching and testing most quantitative and conceptual learning objectives in an interactive way. It is inexpensive and easy to use for both students and faculty. The CSB 2000 package of personalized problem sets, specifically designed to complement most general chemistry courses, is a program on CD-ROM for PC Windows users (3.1, 95, or 98), with more than 1500 questions and a 3 1/2-in. record-management disk. There is a separate grade-management disk for the instructor. It has 24 gradable chapters, each with 5 or 6 sections, plus two new chapters that are not graded: Polymer Chemistry and an Appendix of Chemical Skills. Each section begins with a short review of the topic and many have interactive explanations. If students miss an answer, they are given a second chance for 70% credit. If they still miss, the worked-out solution is presented in detail. Students can work each section as many times as they wish to improve their scores. Periodically, the students download their data directly into a PC set up by the instructor. The data can be easily converted into an ASCII file and merged with a spreadsheet. The use of CD-ROM solves the sporadic problems associated with previous versions on 3 1/2-in. disks: software glitches, failed disks, and system incompatibilities. The quality and number of graphics and interactive exercises are much improved in this latest version. I particularly enjoyed the interactive explanations of significant figures and

  18. The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Science Objectives and Mast Unit Description

    Science.gov (United States)

    Maurice, S.; Wiens, R.C.; Saccoccio, M.; Barraclough, B.; Gasnault, O.; Forni, O.; Mangold, N.; Baratoux, D.; Bender, S.; Berger, G.; Bernardin, J.; Berthé, M.; Bridges, N.; Blaney, D.; Bouyé, M.; Caïs, P.; Clark, B.; Clegg, S.; Cousin, A.; Cremers, D.; Cros, A.; DeFlores, L.; Derycke, C.; Dingler, B.; Dromart, G.; Dubois, B.; Dupieux, M.; Durand, E.; d'Uston, L.; Fabre, C.; Faure, B.; Gaboriaud, A.; Gharsa, T.; Herkenhoff, K.; Kan, E.; Kirkland, L.; Kouach, D.; Lacour, J.-L.; Langevin, Y.; Lasue, J.; Le Mouélic, S.; Lescure, M.; Lewin, E.; Limonadi, D.; Manhès, G.; Mauchien, P.; McKay, C.; Meslin, P.-Y.; Michel, Y.; Miller, E.; Newsom, Horton E.; Orttner, G.; Paillet, A.; Parès, L.; Parot, Y.; Pérez, R.; Pinet, P.; Poitrasson, F.; Quertier, B.; Sallé, B.; Sotin, Christophe; Sautter, V.; Séran, H.; Simmonds, J.J.; Sirven, J.-B.; Stiglich, R.; Striebig, N.; Thocaven, J.-J.; Toplis, M.J.; Vaniman, D.

    2012-01-01

    ChemCam is a remote sensing instrument suite on board the "Curiosity" rover (NASA) that uses Laser-Induced Breakdown Spectroscopy (LIBS) to provide the elemental composition of soils and rocks at the surface of Mars from a distance of 1.3 to 7 m, and a telescopic imager to return high resolution context and micro-images at distances greater than 1.16 m. We describe five analytical capabilities: rock classification, quantitative composition, depth profiling, context imaging, and passive spectroscopy. They serve as a toolbox to address most of the science questions at Gale crater. ChemCam consists of a Mast-Unit (laser, telescope, camera, and electronics) and a Body-Unit (spectrometers, digital processing unit, and optical demultiplexer), which are connected by an optical fiber and an electrical interface. We then report on the development, integration, and testing of the Mast-Unit, and summarize some key characteristics of ChemCam. This confirmed that nominal or better than nominal performances were achieved for critical parameters, in particular power density (>1 GW/cm2). The analysis spot diameter varies from 350 μm at 2 m to 550 μm at 7 m distance. For remote imaging, the camera field of view is 20 mrad for 1024×1024 pixels. Field tests demonstrated that the resolution (˜90 μrad) made it possible to identify laser shots on a wide variety of images. This is sufficient for visualizing laser shot pits and textures of rocks and soils. An auto-exposure capability optimizes the dynamical range of the images. Dedicated hardware and software focus the telescope, with precision that is appropriate for the LIBS and imaging depths-of-field. The light emitted by the plasma is collected and sent to the Body-Unit via a 6 m optical fiber. The companion to this paper (Wiens et al. this issue) reports on the development of the Body-Unit, on the analysis of the emitted light, and on the good match between instrument performance and science specifications.

  19. Air pollution modeling over very complex terrain: An evaluation of WRF-Chem over Switzerland for two 1-year periods

    Science.gov (United States)

    Ritter, Mathias; Müller, Mathias D.; Tsai, Ming-Yi; Parlow, Eberhard

    2013-10-01

    The fully coupled chemistry module (WRF-Chem) within the Weather Research and Forecasting (WRF) model has been implemented over a Swiss domain for the years 2002 and 1991. The very complex terrain requires a high horizontal resolution (2 × 2 km2), which is achieved by nesting the Swiss domain into a coarser European one. The temporal and spatial distribution of O3, NO2 and PM10 as well as temperature and solar radiation are evaluated against ground-based measurements. The model performs well for the meteorological parameters with Pearson correlation coefficients of 0.92 for temperature and 0.88-0.89 for solar radiation. Temperature has root mean square errors (RMSE) of 3.30 K and 3.51 K for 2002 and 1991 and solar radiation has RMSEs of 122.92 and 116.35 for 2002 and 1991, respectively. For the modeled air pollutants, a multi-linear regression post-processing was used to eliminate systematic bias. Seasonal variations of post-processed air pollutants are represented correctly. However, short-term peaks of several days are not captured by the model. Averaged daily maximum and daily values of O3 achieved Pearson correlation coefficients of 0.69-0.77 whereas averaged NO2 and PM10 had the highest correlations for yearly average values (0.68-0.78). The spatial distribution reveals the importance of PM10 advection from the Po valley to southern Switzerland (Ticino). The absolute errors are ranging from - 10 to 15 μg/m3 for ozone, - 9 to 3 μg/m3 for NO2 and - 4 to 3 μg/m3 for PM10. However, larger errors occur along heavily trafficked roads, in street canyons or on mountains. We also compare yearly modeled results against a dedicated Swiss dispersion model for NO2 and PM10. The dedicated dispersion model has a slightly better statistical performance, but WRF-Chem is capable of computing the temporal evolution of three-dimensional data for a variety of air pollutants and meteorological parameters. Overall, WRF-Chem with the application of post-processing algorithms can

  20. DayCent-Chem Simulations of Ecological and Biogeochemical Processes of Eight Mountain Ecosystems in the United States

    Science.gov (United States)

    Hartman, Melannie D.; Baron, Jill S.; Clow, David W.; Creed, Irena F.; Driscoll, Charles T.; Ewing, Holly A.; Haines, Bruce D.; Knoepp, Jennifer; Lajtha, Kate; Ojima, Dennis S.; Parton, William J.; Renfro, Jim; Robinson, R. Bruce; Van Miegroet, Helga; Weathers, Kathleen C.; Williams, Mark W.

    2009-01-01

    Atmospheric deposition of nitrogen (N) and sulfur (S) cause complex responses in ecosystems, from fertilization to forest ecosystem decline, freshwater eutrophication to acidification, loss of soil base cations, and alterations of disturbance regimes. DayCent-Chem, an ecosystem simulation model that combines ecosystem nutrient cycling and plant dynamics with aqueous geochemical equilibrium calculations, was developed to address ecosystem responses to combined atmospheric N and S deposition. It is unique among geochemically-based models in its dynamic biological cycling of N and its daily timestep for investigating ecosystem and surface water chemical response to episodic events. The model was applied to eight mountainous watersheds in the United States. The sites represent a gradient of N deposition across locales, from relatively pristine to N-saturated, and a variety of ecosystem types and climates. Overall, the model performed best in predicting stream chemistry for snowmelt-dominated sites. It was more difficult to predict daily stream chemistry for watersheds with deep soils, high amounts of atmospheric deposition, and a large degree of spatial heterogeneity. DayCent-Chem did well in representing plant and soil carbon and nitrogen pools and fluxes. Modeled stream nitrate (NO3-) and ammonium (NH4+) concentrations compared well with measurements at all sites, with few exceptions. Simulated daily stream sulfate (SO42-) concentrations compared well to measured values for sites where SO42- deposition has been low and where SO42- adsorption/desorption reactions did not seem to be important. The concentrations of base cations and silica in streams are highly dependent on the geochemistry and weathering rates of minerals in each catchment, yet these were rarely, if ever, known. Thus, DayCent-Chem could not accurately predict weathering products for some catchments. Additionally, few data were available for exchangeable soil cations or the magnitude of base cation

  1. Modelling of Impulsional pH Variations Using ChemFET-Based Microdevices: Application to Hydrogen Peroxide Detection

    Directory of Open Access Journals (Sweden)

    Abdou Karim Diallo

    2014-02-01

    Full Text Available This work presents the modelling of impulsional pH variations in microvolume related to water-based electrolysis and hydrogen peroxide electrochemical oxidation using an Electrochemical Field Effect Transistor (ElecFET microdevice. This ElecFET device consists of a pH-Chemical FET (pH-ChemFET with an integrated microelectrode around the dielectric gate area in order to trigger electrochemical reactions. Combining oxidation/reduction reactions on the microelectrode, water self-ionization and diffusion properties of associated chemical species, the model shows that the sensor response depends on the main influential parameters such as: (i polarization parameters on the microelectrode, i.e., voltage (Vp and time (tp; (ii distance between the gate sensitive area and the microelectrode (d; and (iii hydrogen peroxide concentration ([H2O2]. The model developed can predict the ElecFET response behaviour and creates new opportunities for H2O2-based enzymatic detection of biomolecules.

  2. A statistical downscaling approach for roadside NO2 concentrations: Application to a WRF-Chem study for Berlin

    Science.gov (United States)

    Kuik, Friderike; Lauer, Axel; von Schneidemesser, Erika; Butler, Tim

    2017-04-01

    Many European cities continue to struggle with meeting the European air quality limits for NO2. In Berlin, Germany, most of the exceedances in NO2 recorded at monitoring sites near busy roads can be largely attributed to emissions from traffic. In order to assess the impact of changes in traffic emissions on air quality at policy relevant scales, we combine the regional atmosphere-chemistry transport model WRF-Chem at a resolution of 1kmx1km with a statistical downscaling approach. Here, we build on the recently published study evaluating the performance of a WRF-Chem setup in representing observed urban background NO2 concentrations from Kuik et al. (2016) and extend this setup by developing and testing an approach to statistically downscale simulated urban background NO2 concentrations to street level. The approach uses a multilinear regression model to relate roadside NO2 concentrations observed with the municipal monitoring network with observed NO2 concentrations at urban background sites and observed traffic counts. For this, the urban background NO2 concentrations are decomposed into a long term, a synoptic and a diurnal component using the Kolmogorov-Zurbenko filtering method. We estimate the coefficients of the regression model for five different roadside stations in Berlin representing different street types. In a next step we combine the coefficients with simulated urban background concentrations and observed traffic counts, in order to estimate roadside NO2 concentrations based on the results obtained with WRF-Chem at the five selected stations. In a third step, we extrapolate the NO2 concentrations to all major roads in Berlin. The latter is based on available data for Berlin of daily mean traffic counts, diurnal and weekly cycles of traffic as well as simulated urban background NO2 concentrations. We evaluate the NO2 concentrations estimated with this method at street level for Berlin with additional observational data from stationary measurements and

  3. Towards a Comprehensive Dynamic-chemistry Assimilation for Eos-Chem: Plans and Status in NASA's Data Assimilation Office

    Science.gov (United States)

    Pawson, Steven; Lin, Shian-Jiann; Rood, Richard B.; Stajner, Ivanka; Nebuda, Sharon; Nielsen, J. Eric; Douglass, Anne R.

    2000-01-01

    In order to support the EOS-Chem project, a comprehensive assimilation package for the coupled chemical-dynamical system is being developed by the Data Assimilation Office at NASA GSFC. This involves development of a coupled chemistry/meteorology model and of data assimilation techniques for trace species and meteorology. The model is being developed using the flux-form semi-Lagrangian dynamical core of Lin and Rood, the physical parameterizations from the NCAR Community Climate Model, and atmospheric chemistry modules from the Atmospheric Chemistry and Dynamics branch at NASA GSFC. To date the following results have been obtained: (i) multi-annual simulations with the dynamics-radiation model show the credibility of the package for atmospheric simulations; (ii) initial simulations including a limited number of middle atmospheric trace gases reveal the realistic nature of transport mechanisms, although there is still a need for some improvements. Samples of these results will be shown. A meteorological assimilation system is currently being constructed using the model; this will form the basis for the proposed meteorological/chemical assimilation package. The latter part of the presentation will focus on areas targeted for development in the near and far terms, with the objective of Providing a comprehensive assimilation package for the EOS-Chem science experiment. The first stage will target ozone assimilation. The plans also encompass a reanalysis (ReSTS) for the 1991-1995 period, which includes the Mt. Pinatubo eruption and the time when a large number of UARS observations were available. One of the most challenging aspects of future developments will be to couple theoretical advances in tracer assimilation with the practical considerations of a real environment and eventually a near-real-time assimilation system.

  4. FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres

    Science.gov (United States)

    Stock, Joachim W.; Kitzmann, Daniel; Patzer, A. Beate C.; Sedlmayr, Erwin

    2018-06-01

    For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied method is based on the solution of a system of coupled nonlinear (and linear) algebraic equations, namely the law of mass action and the element conservation equations including charge balance, in many variables. Specifically, the system of equations is decomposed into a set of coupled nonlinear equations in one variable each, which are solved analytically whenever feasible to reduce computation time. Notably, the electron density is determined by using the method of Nelder and Mead at low temperatures. The program is written in object-oriented C++ which makes it easy to couple the code with other programs, although a stand-alone version is provided. FastChem can be used in parallel or sequentially and is available under the GNU General Public License version 3 at https://github.com/exoclime/FastChem together with several sample applications. The code has been successfully validated against previous studies and its convergence behavior has been tested even for extreme physical parameter ranges down to 100 K and up to 1000 bar. FastChem converges stable and robust in even most demanding chemical situations, which posed sometimes extreme challenges for previous algorithms.

  5. E4CHEM. A simulation program for the fate of chemicals in the environment. Handbook. User`s guide and description. Version 3.6. December 1995

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, R [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Projektgruppe Umweltgefaehrdungspotentiale von Chemikalien; Drescher-Kaden, U [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Projektgruppe Umweltgefaehrdungspotentiale von Chemikalien; Muenzer, B [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Projektgruppe Umweltgefaehrdungspotentiale von Chemikalien

    1996-02-01

    The predominant aims of E4CHEM are: Deterministic description of the chemical`s behavior in the environment with varying ecoparameters including the special aspects; Behavior of the same chemical in different compartments; Behavior of different chemicals in the same compartment with the same ecoparameters; Tracing back of chemicals detected in the environment to the possible source by means of check procedures like in EXWAT, one of the E4CHEM models; Discharge of the user from extensive calculation operations; Interpretation of experimental results. In combination with statistics and algebraic tools (lattice theory) but not included in E4CHEM yet: Selection of descriptors as tool for priority setting; Identification and ranking of chemicals according to their risk to the environment by comparing descriptors within descriptor matrices about the behavior of chemicals deived from the different models. Furthermore: Identification of chemical applicable as reference substances with respect to environmental behavior. The program E4CHEM is described in this manual. (orig./SR)

  6. Feasibility of Integration of Selected Aspects of (CBA) Chemistry, (CHEMS) Chemistry and (PSSC) Physics into a Two Year Physical Science Sequence.

    Science.gov (United States)

    Fiasca, Michael Aldo

    Compared, for selected outcomes, were integrated chemistry-physics courses with chemistry and physics courses taught separately. Three classes studying integrated Physical Science Study Committee (PSSC)-Chemical Bond Approach (CBA), and three classes studying integrated Physical Science Study Committee-Chemical Education Materials Study (CHEMS)…

  7. ConfChem Conference on Flipped Classroom: Reclaiming Face Time--How an Organic Chemistry Flipped Classroom Provided Access to Increased Guided Engagement

    Science.gov (United States)

    Trogden, Bridget G.

    2015-01-01

    Students' active engagement is one of the most critical challenges to any successful learning environment. The blending of active engagement along with rich, meaningful content is necessary for chemical educators to re-examine the purpose of the chemistry classroom. The Spring 2014 ConfChem conference, Flipped Classroom, was held from May 9 to…

  8. Photochemical Pollution Modeling of Ozone at Metropolitan Area of Porto Alegre - RS/Brazil using WRF/Chem

    Science.gov (United States)

    Cuchiara, G. C.; Carvalho, J.

    2013-05-01

    One of the main problems related to air pollution in urban areas is caused by photochemical oxidants, particularly troposphere ozone (O3), which is considered a harmful substance. The O3 precursors (carbon monoxide CO, nitrogen oxides NOx and hydrocarbons HCs) are predominantly of anthropogenic origin in these areas, and vehicles are the main emission sources. Due to the increased urbanization and industrial development in recent decades, air pollutant emissions have increased likewise, mainly by mobile sources in the highly urbanized and developed areas, such as the Metropolitan Area of Porto Alegre-RS (MAPA). According to legal regulations implemented in Brazil in 2005, which aimed at increasing the fraction of biofuels in the national energy matrix, 2% biodiesel were supposed to be added to the fuel mixture within three years, and up to 5% after eight years of implementation of these regulations. Our work performs an analysis of surface concentrations for O3, NOx, CO, and HCs through numerical simulations with WRF/Chem (Weather Research and Forecasting model with Chemistry). The model is validated against observational data obtained from the local urban air quality network for the period from January 5 to 9, 2009 (96 hours). One part of the study focused on the comparison of simulated meteorological variables, to observational data from two stations in MAPA. The results showed that the model simulates well the diurnal evolution of pressure and temperature at the surface, but is much less accurate for wind speed. Another part included the evaluation of model results of WRF/Chem for O3 versus observed data at air quality stations Esteio and Porto Alegre. Comparisons between simulated and observed O3 revealed that the model simulates well the evolution of the observed values, but on many occasions the model did not reproduce well the maximum and minimum concentrations. Finally, a preliminary quantitative sensitivity study on the impact of biofuel on the

  9. Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

    Directory of Open Access Journals (Sweden)

    Q. Yang

    2011-12-01

    Full Text Available This study assesses the ability of the recent chemistry version (v3.3 of the Weather Research and Forecasting (WRF-Chem model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS, Clouds and Earth's Radiant Energy System (CERES, and GOES-10 are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October–16 November 2008 WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter is also compared to a simulation (MET hereafter with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties, and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with

  10. Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

    Energy Technology Data Exchange (ETDEWEB)

    Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

    2014-06-01

    As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

  11. Evaluation of aerosol optical properties of GEOS-Chem over East Asia during the DRAGON-Asia 2012 campaign

    Science.gov (United States)

    Jo, D. S.; Park, R.; Kim, J.

    2015-12-01

    A nested version of 3-D chemical transport model (GEOS-Chem v9-01-02) is evaluated over East Asia during the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-Asia 2012 campaign period, focusing on fine-mode aerosol optical depth (fAOD) and single scattering albedo (SSA). Both are important to assess the effect of anthropogenic aerosols on climate. We compare the daily mean simulated optical properties of aerosols with the observations from DRAGON-Asia campaign for March-May, 2012 (provided in level 2.0: cloud screened and quality assured). We find that the model reproduces the observed daily variability of fAOD (R=0.67), but overestimates the magnitude by 30%, which is in general consistent with other global model comparisons from ACCMIP. However, a significant high bias in the model is found compared to the observed SSA at 440 nm, which is important for determining the sign of aerosol radiative forcing. In order to understand causes for this gap we conduct several sensitivity tests by changing source magnitudes and input parameters of aerosols, affecting the aerosol optical properties under various atmospheric conditions, which allows us to reduce the gap and to find the optimal values in the model.

  12. Simulation of West African air pollution during the DACCIWA experiment with the GEOS-Chem West African regional model.

    Science.gov (United States)

    Morris, Eleanor; Evans, Mathew

    2017-04-01

    Pollutant emissions from West African cities are forecast to increase rapidly in future years because of extensive economic and population growth, together with poorly regulated industrialisation and urbanisation. Observational constraints in this region are few, leading to poor understanding of present-day air pollution in this region. To increase our understanding of the processes controlling air pollutants over the region, airborne observations were made from three research aircraft based out of Lomé, Togo during the DACCIWA field campaign in June-July 2016. A new 0.25x0.3125 degree West Africa regional version of the GEOS-Chem offline chemical transport model has also been developed to explore the processes controlling pollutants over the region. We evaluate the model using the aircraft data and focus on primary (CO, SO2, NOx, VOCs) and secondary pollutants (O3, aerosol). We find significant differences between the model and the measurements for certain primary compounds which is indicative of significant uncertainties in the base (EDGAR) emissions. For CO (a general tracer of pollution) we evaluate the role of different emissions sources (transport, low temperature combustion, power generation) in determining its concentration in the region. We conclude that the leading cause of uncertainty in our simulation is associated with the emissions datasets and explore the impact of using differing datasets.

  13. PREDIKSI SEBARAN ASAP KEBAKARAN HUTAN/LAHAN MENGGUNAKAN WRF/CHEM (Studi Kasus: Tanggal 14 dan 20 Juni 2012, Pekanbaru-Riau

    Directory of Open Access Journals (Sweden)

    Eko Heriyanto

    2015-01-01

    Full Text Available Penelitian ini bertujuan mengembangkan prediksi sebaran asap kebakaran hutan/lahan di wilayah Indonesia. Simulasi prediksi sebaran  asap (hindcast menggunakan model Weather Research and Forecasting with CHEMistry (WRF/CHEM pada kasus kebakaran hutan/lahan tanggal 14 dan 20 Juni 2012 di wilayah Pekanbaru-Riau. Dalam penelitian ini digunakan data luaran WRF resolusi 25 km dan emisi global . Hasil simulasi  konsentrasi Carbon Monoxide (CO luaran WRF/CHEM menggambarkan pola yang identik dengan hasil luaran Monitoring Atmospheric Composition and Climate (MACC-Reanalysis 1.10. Dilakukan juga analisis kualitatif terhadap hasil simulasi kedua model dengan citra satelit Aqua-Terra MODIS, NOAA-18, dan total column CO Atmospheric Infrared Sounder (AIRS dari NASA. Korelasi simulasi kedua model menunjukkan nilai yang baik antara 0.55 – 0.83. Secara umum dapat disimpulkan bahwa WRF/CHEM mampu mensimulasikan sebaran asap kebakaran hutan/lahan secara akurat. Hasil penelitian ini bisa menjadi salah satu langkah awal dalam pengembangan sistem peringatan dini sebaran asap kebakaran hutan/lahan di wilayah Indonesia.   This study aims to develop a predictive distribution of forest fire smoke/land in the territory of Indonesia. The simulation of smoke spread prediction (hindcast is using the Weather Research and Forecasting Model with CHEMistry (WRF/CHEM in the case of forest fires/land dated June 14, 2012 in Pekanbaru-Riau region. This study uses the WRF data output resolution 25 km and global emissions. Carbon Monoxide concentration simulation results (CO which is the WRF/CHEM output describes patterns that are identical to the results of Monitoring Atmospheric Composition and Climate (MACC-Reanalysis 1.1250 outcomes. a qualitative analysis of the results of the both simulation models with satellite imagery MODIS Aqua-Terra,NOAA-18 and the Total column CO Atmospheric Infrared Sounder (Airs from NASA has  been conducted as well. Both simulation models show a

  14. Diversity of Rock Compositions at Gale Crater Observed by ChemCam and APXS on Curiosity, and Comparison to Meteorite and Orbital Observations

    Science.gov (United States)

    Wiens, R. C.; Maurice, S.; Grotzinger, J. P.; Gellert, R.; Mangold, N.; Sautter, V.; Ollila, A.; Dyar, M. D.; Le Mouelic, S.; Ehlmann, B. L.; Clegg, S. M.; Lanza, N.; Cousin, A.; Forni, O.; Gasnault, O.; Lasue, J.; Blaney, D. L.; Newsom, H. E.; Herkenhoff, K. E.; Anderson, R. B.; D'Uston, L.; Bridges, N. T.; Fabre, C.; Meslin, P.; Johnson, J.; Vaniman, D.; Bridges, J.; Dromart, G.; Schmidt, M. E.; Team, M.

    2013-12-01

    Gale crater was selected as the Curiosity landing site because of the apparent sedimentary spectral signatures seen from orbit. Sedimentary materials on Mars have to this point showed very little expression of major element mobility, so compositions of precursor igneous minerals play a strong role in the compositions of sediments. In addition, pebbles and float rocks on Bradbury Rise (sols 0-50, > 324) appear to be mostly igneous in origin, and are assumed to have been carried down from the crater rim. Overall in the first year on Mars ChemCam obtained >75,000 LIBS spectra on > 2,000 observation points, supported by > 1,000 RMI images, and APXS obtained a significant number of observations. These show surprisingly variable compositions. The mean ChemCam compositions for Bradbury Rise dust-free rocks and pebbles (62 locations) give SiO2 = 56%, FeOT = 16% and show high alkalis consistent with Jake Matijevic (sol ~47) APXS Na2O ~6.6 wt%. ChemCam observations on the conglomerate Link (sol 27) gave Rb > 150 ppm and Sr > 1500 ppm. These compositions imply the presence of abundant alkali feldspars in the material infilling the lower parts of Gale crater. They are generally consistent with the more feldspar-rich SNC meteorites but show a radical departure from larger scale orbital observations, e.g., GRS, raising the question of how widespread these compositions are outside of Gale crater. Sedimentary materials at Yellowknife Bay encompassing the Sheepbed (sols 125-300) and Shaler (sols 121, 311-324) units, potentially including Point Lake (sols 301-310) and Rocknest (sols 57-97), appear to have incorporated varying amounts of igneous source materials. Seven rocks investigated at Rocknest show significant additions of Fe, with mean FeOT = 25% (154 locations), suggesting that FeO was a cementing agent. ChemCam observations at Shaler show varying amounts of alkali feldspar (i.e., related to Bradbury Rise), Fe-rich material (Rocknest-like), and potassium-rich material

  15. ChemSearch Journal

    African Journals Online (AJOL)

    Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. Journal Homepage Image. Chemsearch Journal is a peer – reviewed journal that publishes original research work, scientific papers and technical reports in all the field of Chemistry (pure science, agriculture, environmental science, ...

  16. Chem Gems & Joules

    Science.gov (United States)

    Mason, Diana S.

    2002-09-01

    Learn about the chemistry (and some physics) of optical discs such as CDs, CD-ROMs, and DVDs from David Birkett (p 1081). Beginning on p 1088, Johnson and Yalkowsky present some neat models (commercial or build-yourself) that assemble of their own accord into appropriate structures for liquid and solid water. Do you need a low-cost, small-scale heating device? How about adapting a soldering iron as described on p 1109? If you are interested in cooperative learning, the comparison with lecturing that begins on p 1131 will provide useful information. The latest in our series commemorating the centenary of the Nobel Prizes begins on p 1055. The many interconnections among the research of prizewinners described in this series provides interesting tidbits to humanize chemical kinetics. Do you have hydrogen peroxide, sulfur, or potassium chromate in your lab or chemical storage area? Learn about hazards of these substances from the letter to the editor on p 1070 and the CLIPs on p 1063, p 1064, and p 1065. Finally, keep up with chemical education news at the ACS and the NSF by reading the statements of candidates for the ACS presidency (p 1036 and p 1037) and the commentary by Ellis on p 1034.

  17. ChemView

    Data.gov (United States)

    U.S. Environmental Protection Agency — Search tool developed to provide stakeholders access to various TSCA chemicals, and health and safety information. The tool also provides EPA assessments and actions...

  18. Simulated effect of timing and Pt quantity injected on On-line NobleChem application on total fuel liftoff

    International Nuclear Information System (INIS)

    Pop, M.G.; Riddle, J.M.; Lamanna, L.S.; Gregorich, C.; Hoornik, A.

    2015-01-01

    Total liftoff is a measure of fuel performance and a risk indicator for fuel reliability. Fuel operability and license limits are directly related to the expected total lifetime liftoff. AREVA's continued commitment to zero fuel failure is expressed, among other efforts, in the continued development and improvement of its fuel cladding corrosion and crud risk assessment tools. The AREVA models used to assess and predict crud deposition on BWR cores over their lifespan have been refined by the development and incorporation of the PEZOG tool in response to the move in the industry to the On-Line NobleChem TM (OLNC) technology. PEZOG models the platinum-enhanced zirconium oxide growth of fuel cladding when exposed to platinum during operation. Depending on the local chemistry and radiation condition, noble metals act as catalysts for many reactions, including but not limited to hydrogen oxidation and oxygen reduction. OLNC's intention is to catalyze the hydrogen and oxygen recombination reaction for core internals protection. However, research has indicated that noble metals catalyze the oxygen reduction under the chemistry and radiation conditions as experienced in the pores of crud deposits, and hence, can increase the corrosion rate of zirconium alloy cladding. The developed PEZOG module calculates the oxide thickness as a function of platinum injection strategy. The stratified nature of oxide and crud layers formed on fuel cladding surfaces is reflected in the calculations as are the different platinum interaction in each of the layers. This paper presents examples of the evaluation of various aspects of the platinum injection strategies and their influence on the oxide growth enhancement as applied to conditions of a U.S. plant. (authors)

  19. ChemCam Passive Sky Spectroscopy at Gale Crater, Mars: Interannual Variability in Dust Aerosol Particle Size, Missing Water Vapor, and the Molecular Oxygen Problem

    Science.gov (United States)

    McConnochie, T. H.; Smith, M. D.; Wolff, M. J.; Bender, S. C.; Lemmon, M. T.; Wiens, R. C.; Maurice, S.; Gasnault, O.; Lasue, J.; Meslin, P. Y.; Harri, A. M.; Genzer, M.; Kemppinen, O.; Martinez, G.; DeFlores, L. P.; Blaney, D. L.; Johnson, J. R.; Bell, J. F., III; Trainer, M. G.; Lefèvre, F.; Atreya, S. K.; Mahaffy, P. R.; Wong, M. H.; Franz, H. B.; Guzewich, S.; Villanueva, G. L.; Khayat, A. S.

    2017-12-01

    The Mars Science Laboratory's (MSL) ChemCam spectrometer measures atmospheric aerosol properties and gas abundances by operating in passive mode and observing scattered sky light at two different elevation angles. We have previously [e. g. 1, 2] presented the methodology and results of these ChemCam Passive Sky observations. Here we will focus on three of the more surprising results that we have obtained: (1) depletion of the column water vapor at Gale Crater relative to that of the surrounding region combined with a strong enhancement of the local column water vapor relative to pre-dawn in-situ measurements, (2) an interannual change in the effective particle size of dust aerosol during the aphelion season, and (3) apparent seasonal and interannual variability in molecular oxygen that differs significantly from the expected behavior of a non-condensable trace gas and differs significantly from global climate model expectations. The ChemCam passive sky water vapor measurements are quite robust but their interpretation depends on the details of measurements as well as on the types of water vapor vertical distributions that can be produced by climate models. We have a high degree of confidence in the dust particle size changes but since aerosol results in general are subject to a variety of potential systematic effects our particle size results would benefit from confirmation by other techniques [c.f. 3]. For the ChemCam passive sky molecular oxygen results we are still working to constrain the uncertainties well enough to confirm the observed surprising behavior, motivated by similarly surprising atmospheric molecular oxygen variability observed by MSL's Sample Analysis at Mars (SAM) instrument [4]. REFERENCES: [1] McConnochie, et al. (2017), Icarus (submitted). [2] McConnochie, et al. (2017), abstract # 3201, The 6th International Workshop on the Mars Atmosphere: Granada, Spain. [3] Vicente-Retortillo et al. (2017), GRL, 44. [4] Trainer et al. (2017), 2017 AGU Fall

  20. Temperature-referenced high-sensitivity point-probe optical fiber chem-sensors based on cladding etched fiber Bragg gratings

    OpenAIRE

    Zhou, Kaiming; Chen, Xianfeng F.; Zhang, Lin; Bennion, Ian

    2004-01-01

    Point-probe optical fiber chem-sensors have been implemented using cladding etched fiber Bragg gratings. The sensors possess refractive index sensing capability that can be utilized to measure chemical concentrations. The Bragg wavelength shift reaches 8 nm when the index of surrounding medium changes from 1.33 to 1.44, giving maximum sensitivity more than 10 times higher than that of previously reported devices. More importantly, the dual-grating configuration of the point-probe sensors offe...

  1. Chemical effects in 11-year solar cycle simulations with the Freie Universität Berlin Climate Middle Atmosphere Model with online chemistry (FUB-CMAM-CHEM)

    OpenAIRE

    U. Langematz; J. Grenfell; K. Matthes; P. Mieth; M. Kunze; B. Steil; C. Brühl;  

    2005-01-01

    The impact of 11-year solar cycle variations on stratospheric ozone (O3) is studied with the Freie Universität Berlin Climate Middle Atmosphere Model with interactive chemistry (FUB-CMAM-CHEM). To consider the effect of variations in charged particle precipitation we included an idealized NO x source in the upper mesosphere representing relativistic electron precipitation (REP). Our results suggest that the NO x source by particles and its transport from the mesosphere to the stratosphe...

  2. Exploring Natural Products from the Biodiversity of Pakistan for Computational Drug Discovery Studies: Collection, Optimization, Design and Development of A Chemical Database (ChemDP).

    Science.gov (United States)

    Mirza, Shaher Bano; Bokhari, Habib; Fatmi, Muhammad Qaiser

    2015-01-01

    Pakistan possesses a rich and vast source of natural products (NPs). Some of these secondary metabolites have been identified as potent therapeutic agents. However, the medicinal usage of most of these compounds has not yet been fully explored. The discoveries for new scaffolds of NPs as inhibitors of certain enzymes or receptors using advanced computational drug discovery approaches are also limited due to the unavailability of accurate 3D structures of NPs. An organized database incorporating all relevant information, therefore, can facilitate to explore the medicinal importance of the metabolites from Pakistani Biodiversity. The Chemical Database of Pakistan (ChemDP; release 01) is a fully-referenced, evolving, web-based, virtual database which has been designed and developed to introduce natural products (NPs) and their derivatives from the biodiversity of Pakistan to Global scientific communities. The prime aim is to provide quality structures of compounds with relevant information for computer-aided drug discovery studies. For this purpose, over 1000 NPs have been identified from more than 400 published articles, for which 2D and 3D molecular structures have been generated with a special focus on their stereochemistry, where applicable. The PM7 semiempirical quantum chemistry method has been used to energy optimize the 3D structure of NPs. The 2D and 3D structures can be downloaded as .sdf, .mol, .sybyl, .mol2, and .pdb files - readable formats by many chemoinformatics/bioinformatics software packages. Each entry in ChemDP contains over 100 data fields representing various molecular, biological, physico-chemical and pharmacological properties, which have been properly documented in the database for end users. These pieces of information have been either manually extracted from the literatures or computationally calculated using various computational tools. Cross referencing to a major data repository i.e. ChemSpider has been made available for overlapping

  3. Coupling aerosol-cloud-radiative processes in the WRF-Chem model: Investigating the radiative impact of elevated point sources

    Directory of Open Access Journals (Sweden)

    E. G. Chapman

    2009-02-01

    Full Text Available The local and regional influence of elevated point sources on summertime aerosol forcing and cloud-aerosol interactions in northeastern North America was investigated using the WRF-Chem community model. The direct effects of aerosols on incoming solar radiation were simulated using existing modules to relate aerosol sizes and chemical composition to aerosol optical properties. Indirect effects were simulated by adding a prognostic treatment of cloud droplet number and adding modules that activate aerosol particles to form cloud droplets, simulate aqueous-phase chemistry, and tie a two-moment treatment of cloud water (cloud water mass and cloud droplet number to precipitation and an existing radiation scheme. Fully interactive feedbacks thus were created within the modified model, with aerosols affecting cloud droplet number and cloud radiative properties, and clouds altering aerosol size and composition via aqueous processes, wet scavenging, and gas-phase-related photolytic processes. Comparisons of a baseline simulation with observations show that the model captured the general temporal cycle of aerosol optical depths (AODs and produced clouds of comparable thickness to observations at approximately the proper times and places. The model overpredicted SO2 mixing ratios and PM2.5 mass, but reproduced the range of observed SO2 to sulfate aerosol ratios, suggesting that atmospheric oxidation processes leading to aerosol sulfate formation are captured in the model. The baseline simulation was compared to a sensitivity simulation in which all emissions at model levels above the surface layer were set to zero, thus removing stack emissions. Instantaneous, site-specific differences for aerosol and cloud related properties between the two simulations could be quite large, as removing above-surface emission sources influenced when and where clouds formed within the modeling domain. When summed spatially over the finest

  4. Impacts of aerosols on seasonal precipitation and snowpack in California based on convection-permitting WRF-Chem simulations

    Science.gov (United States)

    Wu, Longtao; Gu, Yu; Jiang, Jonathan H.; Su, Hui; Yu, Nanpeng; Zhao, Chun; Qian, Yun; Zhao, Bin; Liou, Kuo-Nan; Choi, Yong-Sang

    2018-04-01

    A version of the WRF-Chem model with fully coupled aerosol-meteorology-snowpack is employed to investigate the impacts of various aerosol sources on precipitation and snowpack in California. In particular, the impacts of locally emitted anthropogenic and dust aerosols, and aerosols transported from outside California are studied. We differentiate three pathways of aerosol effects: aerosol-radiation interaction (ARI), aerosol-snow interaction (ASI), and aerosol-cloud interaction (ACI). The convection-permitting model simulations show that precipitation, snow water equivalent (SWE), and surface air temperature averaged over the whole domain (34-42° N, 117-124° W, not including ocean points) are reduced when aerosols are included, therefore reducing large biases in these variables due to the absence of aerosol effects in the model. Aerosols affect California water resources through the warming of mountaintops and the reduction of precipitation; however, different aerosol sources play different roles in changing surface temperature, precipitation, and snowpack in California by means of various weights of the three pathways. ARI by all aerosols mainly cools the surface, leading to slightly increased SWE over the mountains. Locally emitted dust aerosols warm the surface of mountaintops through ASI, in which the reduced snow albedo associated with dusty snow leads to more surface absorption of solar radiation and reduced SWE. Transported aerosols and local anthropogenic aerosols play a dominant role in increasing nonprecipitating clouds but reducing precipitation through ACI, leading to reduced SWE and runoff on the Sierra Nevada, as well as the warming of mountaintops associated with decreased SWE and hence lower surface albedo. The average changes in surface temperature from October 2012 to June 2013 are about -0.19 and 0.22 K for the whole domain and over mountaintops, respectively. Overall, the averaged reduction during October to June is about 7 % for precipitation

  5. Impacts of aerosols on seasonal precipitation and snowpack in California based on convection-permitting WRF-Chem simulations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Longtao; Gu, Yu; Jiang, Jonathan; Su, Hui; Yu, Nanpeng; Zhao, Chun; Qian, Yun; Zhao, Bin; Liou, K. N.; Choi, Yong-Sang

    2018-04-23

    A version of the WRF-Chem model with fully coupled aerosol–meteorology–snowpack is employed to investigate the impacts of various aerosol sources on precipitation and snowpack in California. In particular, the impacts of locally emitted anthropogenic and dust aerosols, and aerosols transported from outside California are studied. We differentiate three pathways of aerosol effects: aerosol–radiation interaction (ARI), aerosol–snow interaction (ASI), and aerosol–cloud interaction (ACI). The convection-permitting model simulations show that precipitation, snow water equivalent (SWE), and surface air temperature averaged over the whole domain (34–42° N, 117–124° W, not including ocean points) are reduced when aerosols are included, therefore reducing large biases in these variables due to the absence of aerosol effects in the model. Aerosols affect California water resources through the warming of mountaintops and the reduction of precipitation; however, different aerosol sources play different roles in changing surface temperature, precipitation, and snowpack in California by means of various weights of the three pathways. ARI by all aerosols mainly cools the surface, leading to slightly increased SWE over the mountains. Locally emitted dust aerosols warm the surface of mountaintops through ASI, in which the reduced snow albedo associated with dusty snow leads to more surface absorption of solar radiation and reduced SWE. Transported aerosols and local anthropogenic aerosols play a dominant role in increasing nonprecipitating clouds but reducing precipitation through ACI, leading to reduced SWE and runoff on the Sierra Nevada, as well as the warming of mountaintops associated with decreased SWE and hence lower surface albedo. The average changes in surface temperature from October 2012 to June 2013 are about −0.19 and 0.22 K for the whole domain and over mountaintops, respectively. Overall, the averaged reduction during October to June is about

  6. Sources and characteristics of summertime organic aerosol in the Colorado Front Range: perspective from measurements and WRF-Chem modeling

    Directory of Open Access Journals (Sweden)

    R. Bahreini

    2018-06-01

    Full Text Available The evolution of organic aerosols (OAs and their precursors in the boundary layer (BL of the Colorado Front Range during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ, July–August 2014 was analyzed by in situ measurements and chemical transport modeling. Measurements indicated significant production of secondary OA (SOA, with enhancement ratio of OA with respect to carbon monoxide (CO reaching 0.085±0.003 µg m−3 ppbv−1. At background mixing ratios of CO, up to  ∼  1.8 µg m−3 background OA was observed, suggesting significant non-combustion contribution to OA in the Front Range. The mean concentration of OA in plumes with a high influence of oil and natural gas (O&G emissions was  ∼  40 % higher than in urban-influenced plumes. Positive matrix factorization (PMF confirmed a dominant contribution of secondary, oxygenated OA (OOA in the boundary layer instead of fresh, hydrocarbon-like OA (HOA. Combinations of primary OA (POA volatility assumptions, aging of semi-volatile species, and different emission estimates from the O&G sector were used in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem simulation scenarios. The assumption of semi-volatile POA resulted in greater than a factor of 10 lower POA concentrations compared to PMF-resolved HOA. Including top-down modified O&G emissions resulted in substantially better agreements in modeled ethane, toluene, hydroxyl radical, and ozone compared to measurements in the high-O&G-influenced plumes. By including emissions from the O&G sector using the top-down approach, it was estimated that the O&G sector contributed to  <  5 % of total OA, but up to 38 % of anthropogenic SOA (aSOA in the region. The best agreement between the measured and simulated median OA was achieved by limiting the extent of biogenic hydrocarbon aging and consequently biogenic SOA (bSOA production. Despite a lower production of bSOA in

  7. Simulation of Mexico City plumes during the MIRAGE-Mex field campaign using the WRF-Chem model

    Directory of Open Access Journals (Sweden)

    X. Tie

    2009-07-01

    Full Text Available The quantification of tropospheric O3 production in the downwind of the Mexico City plume is a major objective of the MIRAGE-Mex field campaign. We used a regional chemistry-transport model (WRF-Chem to predict the distribution of O3 and its precursors in Mexico City and the surrounding region during March 2006, and compared the model with in-situ aircraft measurements of O3, CO, VOCs, NOx, and NOy concentrations. The comparison shows that the model is capable of capturing the timing and location of the measured city plumes, and the calculated variability along the flights is generally consistent with the measured results, showing a rapid increase in O3 and its precursors when city plumes are detected. However, there are some notable differences between the calculated and measured values, suggesting that, during transport from the surface of the city to the outflow plume, ozone mixing ratios are underestimated by about 0–25% during different flights. The calculated O3-NOx, O3-CO, and O3-NOz correlations generally agree with the measured values, and the analyses of these correlations suggest that photochemical O3 production continues in the plume downwind of the city (aged plume, adding to the O3 already produced in the city and exported with the plume. The model is also used to quantify the contributions to OH reactivity from various compounds in the aged plume. This analysis suggests that oxygenated organics (OVOCs have the highest OH reactivity and play important roles for the O3 production in the aging plume. Furthermore, O3 production per NOx molecule consumed (O3 production efficiency is more efficient in the aged plume than in the young plume near the city. The major contributor to the high O3 production efficiency in the aged plume is the

  8. Radiative effects of light-absorbing particles deposited in snow over Himalayas using WRF-Chem simulations

    Science.gov (United States)

    Sarangi, C.; Qian, Y.; Painter, T. H.; Liu, Y.; Lin, G.; Wang, H.

    2017-12-01

    Radiative forcing induced by light-absorbing particles (LAP) deposited on snow is an important surface forcing. It has been debated that an aerosol-induced increase in atmospheric and surface warming over Tibetan Plateau (TP) prior to the South Asian summer monsoon can have a significant effect on the regional thermodynamics and South Asian monsoon circulation. However, knowledge about the radiative effects due to deposition of LAP in snow over TP is limited. In this study we have used a high-resolution WRF-Chem (coupled with online chemistry and snow-LAP-radiation model) simulations during 2013-2014 to estimate the spatio-temporal variation in LAP deposition on snow, specifically black carbon (BC) and dust particles, in Himalayas. Simulated distributions in meteorology, aerosol concentrations, snow albedo, snow grain size and snow depth are evaluated against satellite and in-situ measurements. The spatio-temporal change in snow albedo and snow grain size with variation in LAP deposition is investigated and the resulting shortwave LAP radiative forcing at surface is calculated. The LAP-radiative forcing due to aerosol deposition, both BC and dust, is higher in magnitude over Himalayan slopes (terrain height below 4 km) compared to that over TP (terrain height above 4 km). We found that the shortwave aerosol radiative forcing efficiency at surface due to increase in deposited mass of BC particles in snow layer ( 25 (W/m2)/ (mg/m2)) is manifold higher than the efficiency of dust particles ( 0.1 (W/m2)/ (mg/m2)) over TP. However, the radiative forcing of dust deposited in snow is similar in magnitude (maximum 20-30 W/m2) to that of BC deposited in snow over TP. This is mainly because the amount of dust deposited in snow over TP can be about 100 times greater than the amount of BC deposited in snow during polluted conditions. The impact of LAP on surface energy balance, snow melting and atmospheric thermodynamics is also examined.

  9. Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

    Science.gov (United States)

    Georgiou, George K.; Christoudias, Theodoros; Proestos, Yiannis; Kushta, Jonilda; Hadjinicolaou, Panos; Lelieveld, Jos

    2018-02-01

    We employ the WRF-Chem model to study summertime air pollution, the intense photochemical activity and their impact on air quality over the eastern Mediterranean. We utilize three nested domains with horizontal resolutions of 80, 16 and 4 km, with the finest grid focusing on the island of Cyprus, where the CYPHEX campaign took place in July 2014. Anthropogenic emissions are based on the EDGAR HTAP global emission inventory, while dust and biogenic emissions are calculated online. Three simulations utilizing the CBMZ-MOSAIC, MOZART-MOSAIC, and RADM2-MADE/SORGAM gas-phase and aerosol mechanisms are performed. The results are compared with measurements from a dense observational network of 14 ground stations in Cyprus. The model simulates T2 m, Psurf, and WD10 m accurately, with minor differences in WS10 m between model and observations at coastal and mountainous stations attributed to limitations in the representation of the complex topography in the model. It is shown that the south-eastern part of Cyprus is mostly affected by emissions from within the island, under the dominant (60 %) westerly flow during summertime. Clean maritime air from the Mediterranean can reduce concentrations of local air pollutants over the region during westerlies. Ozone concentrations are overestimated by all three mechanisms (9 % ≤ NMB ≤ 23 %) with the smaller mean bias (4.25 ppbV) obtained by the RADM2-MADE/SORGAM mechanism. Differences in ozone concentrations can be attributed to the VOC treatment by the three mechanisms. The diurnal variability of pollution and ozone precursors is not captured (hourly correlation coefficients for O3 ≤ 0.29). This might be attributed to the underestimation of NOx concentrations by local emissions by up to 50 %. For the fine particulate matter (PM2.5), the lowest mean bias (9 µg m-3) is obtained with the RADM2-MADE/SORGAM mechanism, with overestimates in sulfate and ammonium aerosols. Overestimation of sulfate aerosols by this mechanism may be

  10. Simulations of organic aerosol concentrations in Mexico City using the WRF-CHEM model during the MCMA-2006/MILAGRO campaign

    Directory of Open Access Journals (Sweden)

    G. Li

    2011-04-01

    Full Text Available Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed to predict the variation and spatial distribution of the organic aerosol concentrations: (1 a traditional 2-product secondary organic aerosol (SOA model with non-volatile primary organic aerosols (POA; (2 a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA (Mexico City Metropolitan Area 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS observations analyzed using the Positive Matrix Factorization (PMF technique at an urban background site (T0 and a suburban background site (T1 in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the

  11. Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

    Science.gov (United States)

    Marelle, Louis; Raut, Jean-Christophe; Law, Kathy S.; Berg, Larry K.; Fast, Jerome D.; Easter, Richard C.; Shrivastava, Manish; Thomas, Jennie L.

    2017-10-01

    In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain-Fritsch + Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

  12. pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

    Science.gov (United States)

    Chen, Daquan; Sun, Kaoxiang; Mu, Hongjie; Tang, Mingtan; Liang, Rongcai; Wang, Aiping; Zhou, Shasha; Sun, Haijun; Zhao, Feng; Yao, Jianwen; Liu, Wanhui

    2012-01-01

    Background In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS) polymer was used for vaginal administration. Methods The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment. Results A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0). Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0. Conclusion This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery. PMID:22679372

  13. Validating the WRF-Chem model for wind energy applications using High Resolution Doppler Lidar data from a Utah 2012 field campaign

    Science.gov (United States)

    Mitchell, M. J.; Pichugina, Y. L.; Banta, R. M.

    2015-12-01

    Models are important tools for assessing potential of wind energy sites, but the accuracy of these projections has not been properly validated. In this study, High Resolution Doppler Lidar (HRDL) data obtained with high temporal and spatial resolution at heights of modern turbine rotors were compared to output from the WRF-chem model in order to help improve the performance of the model in producing accurate wind forecasts for the industry. HRDL data were collected from January 23-March 1, 2012 during the Uintah Basin Winter Ozone Study (UBWOS) field campaign. A model validation method was based on the qualitative comparison of the wind field images, time-series analysis and statistical analysis of the observed and modeled wind speed and direction, both for case studies and for the whole experiment. To compare the WRF-chem model output to the HRDL observations, the model heights and forecast times were interpolated to match the observed times and heights. Then, time-height cross-sections of the HRDL and WRF-Chem wind speed and directions were plotted to select case studies. Cross-sections of the differences between the observed and forecasted wind speed and directions were also plotted to visually analyze the model performance in different wind flow conditions. A statistical analysis includes the calculation of vertical profiles and time series of bias, correlation coefficient, root mean squared error, and coefficient of determination between two datasets. The results from this analysis reveals where and when the model typically struggles in forecasting winds at heights of modern turbine rotors so that in the future the model can be improved for the industry.

  14. Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

    Science.gov (United States)

    Wiens, R.C.; Maurice, S.; Lasue, J.; Forni, O.; Anderson, R.B.; Clegg, S.; Bender, S.; Blaney, D.; Barraclough, B.L.; Cousin, A.; DeFlores, L.; Delapp, D.; Dyar, M.D.; Fabre, C.; Gasnault, O.; Lanza, N.; Mazoyer, J.; Melikechi, N.; Meslin, P.-Y.; Newsom, H.; Ollila, A.; Perez, R.; Tokar, R.; Vaniman, D.

    2013-01-01

    The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

  15. WRF and WRF-Chem v3.5.1 simulations of meteorology and black carbon concentrations in the Kathmandu Valley

    Directory of Open Access Journals (Sweden)

    A. Mues

    2018-06-01

    Full Text Available An evaluation of the meteorology simulated using the Weather Research and Forecast (WRF model for the region of south Asia and Nepal with a focus on the Kathmandu Valley is presented. A particular focus of the model evaluation is placed on meteorological parameters that are highly relevant to air quality such as wind speed and direction, boundary layer height and precipitation. The same model setup is then used for simulations with WRF including chemistry and aerosols (WRF-Chem. A WRF-Chem simulation has been performed using the state-of-the-art emission database, EDGAR HTAP v2.2, which is the Emission Database for Global Atmospheric Research of the Joint Research Centre (JRC of the European Commission, in cooperation with the Task Force on Hemispheric Transport of Air Pollution (TF HTAP organized by the United Nations Economic Commission for Europe, along with a sensitivity simulation using observation-based black carbon emission fluxes for the Kathmandu Valley. The WRF-Chem simulations are analyzed in comparison to black carbon measurements in the valley and to each other.The evaluation of the WRF simulation with a horizontal resolution of 3×3 km2 shows that the model is often able to capture important meteorological parameters inside the Kathmandu Valley and the results for most meteorological parameters are well within the range of biases found in other WRF studies especially in mountain areas. But the evaluation results also clearly highlight the difficulties of capturing meteorological parameters in such complex terrain and reproducing subgrid-scale processes with a horizontal resolution of 3×3 km2. The measured black carbon concentrations are typically systematically and strongly underestimated by WRF-Chem. A sensitivity study with improved emissions in the Kathmandu Valley shows significantly reduced biases but also underlines several limitations of such corrections. Further improvements of the model and of the emission data are

  16. pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

    Directory of Open Access Journals (Sweden)

    Chen D

    2012-05-01

    Full Text Available Daquan Chen,1,2 Kaoxiang Sun,1,2 Hongjie Mu,1 Mingtan Tang,3 Rongcai Liang,1,2 Aiping Wang,1,2 Shasha Zhou,1 Haijun Sun,1 Feng Zhao,1 Jianwen Yao,1 Wanhui Liu1,21School of Pharmacy, Yantai University, 2State Key Laboratory of Longacting and Targeting Drug Delivery Systems, Yantai, 3School of Pharmaceutical Sciences, Shandong University, Jinan, People's Republic of ChinaBackground: In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS polymer was used for vaginal administration.Methods: The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment.Results: A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0. Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0.Conclusion: This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery.Keywords: mPEG-Hz-CHEMS polymer, pH-sensitive liposomes, thermosensitive

  17. Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

    Energy Technology Data Exchange (ETDEWEB)

    Wiens, R.C., E-mail: rwiens@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Maurice, S.; Lasue, J.; Forni, O. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Anderson, R.B. [United States Geological Survey, Flagstaff, AZ (United States); Clegg, S. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Bender, S. [Planetary Science Institute, Tucson, AZ (United States); Blaney, D. [Jet Propulsion Laboratory, Pasadena, CA (United States); Barraclough, B.L. [Planetary Science Institute, Tucson, AZ (United States); Cousin, A. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Deflores, L. [Jet Propulsion Laboratory, Pasadena, CA (United States); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Dyar, M.D. [Mount Holyoke College, South Hadley, MA (United States); Fabre, C. [Georessources, Nancy (France); Gasnault, O. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Lanza, N. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Mazoyer, J. [LESIA, Observatoire de Paris, Meudon (France); Melikechi, N. [Delaware State University, Dover, DE (United States); Meslin, P.-Y. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Newsom, H. [University of New Mexico, Albuquerque, NM (United States); and others

    2013-04-01

    The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

  18. Is ozone model bias driven by errors in cloud predictions? A quantitative assessment using satellite cloud retrievals in WRF-Chem

    Science.gov (United States)

    Ryu, Y. H.; Hodzic, A.; Barré, J.; Descombes, G.; Minnis, P.

    2017-12-01

    Clouds play a key role in radiation and hence O3 photochemistry by modulating photolysis rates and light-dependent emissions of biogenic volatile organic compounds (BVOCs). It is not well known, however, how much of the bias in O3 predictions is caused by inaccurate cloud predictions. This study quantifies the errors in surface O3 predictions associated with clouds in summertime over CONUS using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. Cloud fields used for photochemistry are corrected based on satellite cloud retrievals in sensitivity simulations. It is found that the WRF-Chem model is able to detect about 60% of clouds in the right locations and generally underpredicts cloud optical depths. The errors in hourly O3 due to the errors in cloud predictions can be up to 60 ppb. On average in summertime over CONUS, the errors in 8-h average O3 of 1-6 ppb are found to be attributable to those in cloud predictions under cloudy sky conditions. The contribution of changes in photolysis rates due to clouds is found to be larger ( 80 % on average) than that of light-dependent BVOC emissions. The effects of cloud corrections on O­3 are about 2 times larger in VOC-limited than NOx-limited regimes, suggesting that the benefits of accurate cloud predictions would be greater in VOC-limited than NOx-limited regimes.

  19. The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

    Science.gov (United States)

    Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

    1998-07-01

    To assess a newly developed immunohistochemical detection system, the EnVision++. A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

  20. Chem TV: Choices I, v. 1.5.1 (by B. A. Luceigh, P. Ngo, and J. Chen)

    Science.gov (United States)

    Kraig Steffen, L.

    1999-08-01

    CHEM TV: Sunland, CA, 1998. 24.95, students; 59.95, faculty. This CD-ROM presents a series of interactive overviews and drills for students of organic chemistry. The material covered is generally taught in the first semester. This suite is much more than a simple presentation of material and, for students sufficiently motivated to take the time and work with the problems, will provide valuable review. Five interactive spaces are provided: concentration drills that emphasize recall of related structures/names, reagents/reactions, and stereochemistry; a structural review based on epinephrine; interactive synthesis projects; arcade game reagent review; and a set of timed self-tests. The CD-ROM installed and ran without problem on a Power PC Mac and on a Pentium running Windows 95. The program did fail to run when a student reviewing it switched to a very new version of Windows Quick Time. Most of the drills ran without a problem, although at times it was unclear how to respond to queries. I turned off the music, which would be much less annoying if the loops were simply longer. Publishers are flooding the market with add-on computer-based materials for the various levels of chemistry. Many constitute little more than a stack of overheads. This is one that may be of sufficient value to warrant the extra cost. A large number of examples are provided for many of the areas covered. Most of the graphical interfaces are clear and easy to manipulate, with the exception of a couple of mechanistic screens that had hard-to-figure-out arrows. Two sections, or modules, are of special note. The first of these is the synthesis challenges, where students must choose reactants, reagents, and reaction conditions for a particular reaction. These synthesis problems are well thought out and can be challenging. It is unfortunate that there are only five of them. The Self-Tests module is also of great practical value, forcing students to work through a variety of topics (200 problems) with

  1. Using WRF-Chem to investigate the impact of night time nitrate radical chemistry and N2O5 heterogeneous chemistry on the chemical composition of the UK troposphere.

    Science.gov (United States)

    Archer-Nicholls, S.; Lowe, D.; Utembe, S.; McFiggans, G.

    2012-04-01

    of two flight periods: one during July 2010; the other during January 2011. We have run five model scenarios for both these periods: a base case, with standard emissions and chemistry; two scenarios with standard chemistry, but with halved and doubled NOx transport emissions respectively; and two scenarios with standard emissions, but one without N2O5 heterogeneous chemistry, and the other with the Cl- reaction pathway disabled. We will present results from the application of WRF-Chem to model the regional chemical composition of the atmosphere about the UK. Sensitivities to changing emission profiles and the impact of N2O5 heterogeneous chemistry will be discussed. Preliminary comparisons between model results and aircraft data will be shown. The strengths and weaknesses of our modelling approach, in particular the gains and drawbacks of using a fully coupled online model for use in this campaign, will be highlighted. The wider impacts of the processes investigated on the regional climate and air quality will be further discussed. Allan, B., et. al. (2000); J. Geophys. Res., 105, doi: 10.1046/j.1365-2370.2000.00208. Bertram, T. H., Thornton, J. A. (2009); Atmos. Chem. Phys., 9, 8351-8363, doi: 10.5194/acp-9-8351-2009 Grell, G., et. al. (2005); Atmos. Environ., 39, 6957- 6975. doi: 10.1016/j.atmosenv.2005.04.027 Topping, D., Lowe, D. & McFiggans, G. (2012); Geosci. Model Dev., 5, 1-13. doi:10.5194/gmd-5-1-2012 Watson, L., et. al. (2008); Atmos. Environ., 42, 7196- 7204, doi: 10.1016/j.atmosenv.2008.07.034 Zaveri, R. A., et. al. (2008); J. Geophys. Res., 113, doi:10.1029/2007JD008782

  2. Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

    Directory of Open Access Journals (Sweden)

    L. Marelle

    2017-10-01

    Full Text Available In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols (1 a correction to the sedimentation of aerosols, (2 dimethyl sulfide (DMS oceanic emissions and gas-phase chemistry, (3 an improved representation of the dry deposition of trace gases over seasonal snow, and (4 an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5 correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6 couple and further test the recent KF-CuP (Kain–Fritsch + Cumulus Potential cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC, sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone, the improved surface temperatures over sea ice (surface ozone, BC, and sulfate, and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone. DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

  3. The AtChem On-line model and Electronic Laboratory Notebook (ELN): A free community modelling tool with provenance capture

    Science.gov (United States)

    Young, J. C.; Boronska, K.; Martin, C. J.; Rickard, A. R.; Vázquez Moreno, M.; Pilling, M. J.; Haji, M. H.; Dew, P. M.; Lau, L. M.; Jimack, P. K.

    2010-12-01

    AtChem On-line1 is a simple to use zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any set of chemical reactions can be simulated, in particular the whole Master Chemical Mechanism (MCM2) or any subset of it. Parameters and initial data can be provided through a self-explanatory web form and the resulting model is compiled and run on a dedicated server. The core part of the toolkit, providing a robust solver for thousands of chemical reactions, is written in Fortran and uses SUNDIALS3 CVODE libraries. Chemical systems can be constrained at multiple, user-determined timescales; this enabled studies of radical chemistry at one minute timescales. AtChem On-line is free to use and requires no installation - a web browser, text editor and any compressing software is all the user needs. CPU and storage are provided by the server (input and output data are saved indefinitely). An off-line version is also being developed, which will provide batch processing, an advanced graphical user interface and post-processing tools, for example, Rate of Production Analysis (ROPA) and chainlength analysis. The source code is freely available for advanced users wishing to adapt and run the program locally. Data management, dissemination and archiving are essential in all areas of science. In order to do this in an efficient and transparent way, there is a critical need to capture high quality metadata/provenance for modelling activities. An Electronic Laboratory Notebook (ELN) has been developed in parallel with AtChem Online as part of the EC EUROCHAMP24 project. In order to use controlled chamber experiments to evaluate the MCM, we need to be able to archive, track and search information on all associated chamber model runs, so that they can be used in subsequent mechanism development. Therefore it would be extremely useful if experiment and model metadata/provenance could be easily and automatically stored electronically

  4. QSAR screening of 70,983 REACH substances for genotoxic carcinogenicity, mutagenicity and developmental toxicity in the ChemScreen project

    DEFF Research Database (Denmark)

    Wedebye, Eva Bay; Dybdahl, Marianne; Nikolov, Nikolai Georgiev

    2015-01-01

    The ChemScreen project aimed to develop a screening system for reproductive toxicity based on alternative methods. QSARs can, if adequate, contribute to the evaluation of chemical substances under REACH and may in some cases be applied instead of experimental testing to fill data gaps...... for information requirements. As no testing for reproductive effects should be performed in REACH on known genotoxic carcinogens or germ cell mutagens with appropriate risk management measures implemented, a QSAR pre-screen for 70,983 REACH substances was performed. Sixteen models and three decision algorithms...... were used to reach overall predictions of substances with potential effects with the following result: 6.5% genotoxic carcinogens, 16.3% mutagens, 11.5% developmental toxicants. These results are similar to findings in earlier QSAR and experimental studies of chemical inventories, and illustrate how...

  5. PREP-CHEM-SRC – 1.0: a preprocessor of trace gas and aerosol emission fields for regional and global atmospheric chemistry models

    Directory of Open Access Journals (Sweden)

    S. R. Freitas

    2011-05-01

    Full Text Available The preprocessor PREP-CHEM-SRC presented in the paper is a comprehensive tool aiming at preparing emission fields of trace gases and aerosols for use in atmospheric-chemistry transport models. The considered emissions are from the most recent databases of urban/industrial, biogenic, biomass burning, volcanic, biofuel use and burning from agricultural waste sources. For biomass burning, emissions can be also estimated directly from satellite fire detections using a fire emission model included in the tool. The preprocessor provides emission fields interpolated onto the transport model grid. Several map projections can be chosen. The inclusion of these emissions in transport models is also presented. The preprocessor is coded using Fortran90 and C and is driven by a namelist allowing the user to choose the type of emissions and the databases.

  6. Trace element geochemistry (Li, Ba, Sr, and Rb) using Curiosity's ChemCam: early results for Gale crater from Bradbury Landing Site to Rocknest

    Science.gov (United States)

    Ollila, Ann M.; Newsom, Horton E.; Clark, Benton; Wiens, Roger C.; Cousin, Agnes; Blank, Jen G.; Mangold, Nicolas; Sautter, Violaine; Maurice, Sylvestre; Clegg, Samuel M.; Gasnault, Olivier; Forni, Olivier; Tokar, Robert; Lewin, Eric; Dyar, M. Darby; Lasue, Jeremie; Anderson, Ryan; McLennan, Scott M.; Bridges, John; Vaniman, Dave; Lanza, Nina; Fabre, Cecile; Melikechi, Noureddine; Perett, Glynis M.; Campbell, John L.; King, Penelope L.; Barraclough, Bruce; Delapp, Dorothea; Johnstone, Stephen; Meslin, Pierre-Yves; Rosen-Gooding, Anya; Williams, Josh

    2014-01-01

    The ChemCam instrument package on the Mars rover, Curiosity, provides new capabilities to probe the abundances of certain trace elements in the rocks and soils on Mars using the laser-induced breakdown spectroscopy technique. We focus on detecting and quantifying Li, Ba, Rb, and Sr in targets analyzed during the first 100 sols, from Bradbury Landing Site to Rocknest. Univariate peak area models and multivariate partial least squares models are presented. Li, detected for the first time directly on Mars, is generally low (100 ppm and >1000 ppm, respectively. These analysis locations tend to have high Si and alkali abundances, consistent with a feldspar composition. Together, these trace element observations provide possible evidence of magma differentiation and aqueous alteration.

  7. El Sensor Químico (ChemSensor) como herramienta complementaria en el análisis sensorial de vinos

    OpenAIRE

    Pérez Mateos, Miriam; Giménez Cobo, Lucia; Carrasco Manzano, Juan Atanasio

    2012-01-01

    El Sensor Químico (ChemSensor) o pseudo-nariz electrónica determina la agrupación de alimentos por similitudes y según la distancias entre grupos, a partir del análisis de espectrometría de masas de los compuestos volátiles y/o los ácidos grasos. Se trata de una herramienta excelente como complemento al análisis sensorial. Es muy útil en la clasificación y predicción de productos alimenticios según su origen, procesado y conservación; en la optimización de procesos y en aplicaciones de contro...

  8. A WRF-Chem model study of the impact of VOCs emission of a huge petro-chemical industrial zone on the summertime ozone in Beijing, China

    Science.gov (United States)

    Wei, Wei; Lv, Zhao Feng; Li, Yue; Wang, Li Tao; Cheng, Shuiyuan; Liu, Huan

    2018-02-01

    In China, petro-chemical manufacturing plants generally gather in the particular industrial zone defined as PIZ in some cities, and distinctly influence the air quality of these cities for their massive VOCs emissions. This study aims to quantify the local and regional impacts of PIZ VOCs emission and its relevant reduction policy on the surface ozone based on WRF-Chem model, through the case study of Beijing. Firstly, the model simulation under the actual precursors' emissions over Beijing region for July 2010 is conducted and evaluated, which meteorological and chemical predictions both within the thresholds for satisfactory model performance. Then, according to simulated H2O2/HNO3 ratio, the nature of photochemical ozone formation over Beijing is decided, the VOCs-sensitive regime over the urban areas, NOx-sensitive regime over the northern and western rural areas, and both VOCssbnd and NOx-mixed sensitive regime over the southern and eastern rural areas. Finally, a 30% VOCs reduction scenario (RS) and a 100% VOCs reduction scenario (ZS) for Beijing PIZ are additional simulated by WRF-Chem. The sensitivity simulations imply that the current 30% reduction policy would bring about an O3 increase in the southern and western areas (by +4.7 ppb at PIZ site and +2.1 ppb at LLH station), and an O3 decrease in the urban center (by -1.7 ppb at GY station and -2.5 ppb at DS station) and in the northern and eastern areas (by -1.2 ppb at MYX station), mainly through interfering with the circulation of atmospheric HOx radicals. While the contribution of the total VOCs emission of PIZ to ozone is greatly prominent in the PIZ and its surrounding areas along south-north direction (12.7% at PIZ site on average), but slight in the other areas of Beijing (<3% in other four stations on average).

  9. Modeling of low-temperature plasmas generated using laser-induced breakdown spectroscopy: the ChemCam diagnostic tool on the Mars Science Laboratory Rover

    Science.gov (United States)

    Colgan, James

    2016-05-01

    We report on efforts to model the low-temperature plasmas generated using laser-induced breakdown spectroscopy (LIBS). LIBS is a minimally invasive technique that can quickly and efficiently determine the elemental composition of a target and is employed in an extremely wide range of applications due to its ease of use and fast turnaround. In particular, LIBS is the diagnostic tool used by the ChemCam instrument on the Mars Science Laboratory rover Curiosity. In this talk, we report on the use of the Los Alamos plasma modeling code ATOMIC to simulate LIBS plasmas, which are typically at temperatures of order 1 eV and electron densities of order 10 16 - 17 cm-3. At such conditions, these plasmas are usually in local-thermodynamic equilibrium (LTE) and normally contain neutral and singly ionized species only, which then requires that modeling must use accurate atomic structure data for the element under investigation. Since LIBS devices are often employed in a very wide range of applications, it is therefore desirable to have accurate data for most of the elements in the periodic table, ideally including actinides. Here, we discuss some recent applications of our modeling using ATOMIC that have explored the plasma physics aspects of LIBS generated plasmas, and in particular discuss the modeling of a plasma formed from a basalt sample used as a ChemCam standard1. We also highlight some of the more general atomic physics challenges that are encountered when attempting to model low-temperature plasmas. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396. Work performed in conjunction with D. P. Kilcrease, H. M. Johns, E. J. Judge, J. E. Barefield, R. C. Wiens, S. M. Clegg.

  10. Assessing the Impact of Oil and Natural Gas Activities on Regional Air Quality in the Colorado Northern Front Range using WRF-Chem

    Science.gov (United States)

    Abdioskouei, M.; Carmichael, G. R.

    2017-12-01

    Recent increases in the Natural Gas (NG) production through hydraulic fracturing have questioned the climate benefit of switching from coal-fired to natural gas-fired power plants. Higher than expected levels of methane, VOCs, and NOx have been observed in areas close to oil and NG (OnG) operation facilities. High uncertainty in the OnG emission inventories and methane budget challenge the assessment of OnG impact on air quality and climate and consequently development of effective mitigation policies and control regulations. In this work, we focus on reducing the uncertainties around the OnG emissions by using high resolution (4x4 km2) WRF-Chem simulations coupled with detailed observation from the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ 2014) field campaign. First, we identified the optimal WRF-Chem configurations in the NFR area. We compared the performance of local and non-local Planetary Boundary Layer (PBL) schemes in predicting the PBL height and vertical mixing in the domain. We evaluated the impact of different meteorological and chemical initial and boundary conditions on the model performance. Next, simulations based on optimal configurations were used to assess the performance of the emission inventory (NEI-2011v2). To evaluate the impact of OnG emission on regional air quality and performance of NEI-2011 we tested the sensitivity of the model to the OnG emission. Comparison between simulated values and ground-based and airborne measurements shows a low bias of OnG emission in NEI-2011. Finally, inverse modeling techniques based on emission sensitivity simulations are being used to optimal scaling the OnG emission from the NEI-2011.

  11. Comment on "Rethinking first-principles electron transport theories with projection operators: The problems caused by partitioning the basis set" [J. Chem. Phys. 139, 114104 (2013)

    DEFF Research Database (Denmark)

    Brandbyge, Mads

    2014-01-01

    , different from what would be obtained by using an orthogonal basis, and dividing surfaces defined in real-space. We argue that this assumption is not required to be fulfilled to get exact results. We show how the current/transmission calculated by the standard Greens function method is independent...

  12. A comment on "The interaction of X2 (X = F, Cl, and Br) with active sites of graphite" [Xu et al., Chem. Phys. Lett., 418, 413 (2006)

    Science.gov (United States)

    Lechner, Christoph; Baranek, Philippe; Vach, Holger

    2018-04-01

    In their article, Xu et al. (2006) present the adsorption energies for the chemisorption of the three halogens F2 , Cl2 , and Br2 on the active sites of graphite. The three investigated systems are the three most stable surfaces, (0 0 1), (1 0 0), and (1 1 0); the latter two are also called zigzag and armchair surface, respectively. Due to some inconsistencies in their article, we re-evaluated the results of Xu et al. in order to investigate the impact on the adsorption energies of the halogens. For the (0 0 1) surface, our results agree with Xu et al. However, for the other two surfaces we find major differences. Contrary to Xu et al., we find that the halogens adsorb the strongest on the zigzag surface. The second strongest adsorption is found on the armchair surface for the symmetric configurations, the third strongest for the asymmetric configurations. Several reasons are given which explain this discrepancy. The most striking source of error in the work of Xu et al. is due to the fact that they did not choose the correct spin multiplicities for the model systems which means that they performed the calculations in excited states. This leads to errors between 50 and 600% for the zigzag surface and 3-42% for the armchair surface.

  13. Some comments on 'Jahn-Teller effect in coronene monoanion: a comparative study with corannulene monoanion' [Chem. Phys. 287 (2003) 91

    International Nuclear Information System (INIS)

    Breza, M.

    2003-01-01

    A group-theoretical analysis of Jahn-Teller distortions using step-by-step symmetry descent method is based on consecutive removal of symmetry elements during electron degeneracy splitting. The results of this treatment imply that the Jahn-Teller effect in D 6h parent symmetry group may result in stable geometries of D 2h , D 2 , C 2h , C 2v , C 2 , C i , C s and/or C 1 symmetries. The Jahn-Teller effect in D 5h parent group may result in C 2v , C 2 , C s and/or C 1 stable geometries. All these symmetry groups may correspond to classical saddle points of Jahn-Teller energy hypersurfaces. Possible electronic states in these geometries may be also predicted. Such complex hypersurfaces cannot be described by the classical treatments based on Jahn-Teller active coordinates

  14. Bond-based linear indices of the non-stochastic and stochastic edge-adjacency matrix. 1. Theory and modeling of ChemPhys properties of organic molecules.

    Science.gov (United States)

    Marrero-Ponce, Yovani; Martínez-Albelo, Eugenio R; Casañola-Martín, Gerardo M; Castillo-Garit, Juan A; Echevería-Díaz, Yunaimy; Zaldivar, Vicente Romero; Tygat, Jan; Borges, José E Rodriguez; García-Domenech, Ramón; Torrens, Francisco; Pérez-Giménez, Facundo

    2010-11-01

    Novel bond-level molecular descriptors are proposed, based on linear maps similar to the ones defined in algebra theory. The kth edge-adjacency matrix (E(k)) denotes the matrix of bond linear indices (non-stochastic) with regard to canonical basis set. The kth stochastic edge-adjacency matrix, ES(k), is here proposed as a new molecular representation easily calculated from E(k). Then, the kth stochastic bond linear indices are calculated using ES(k) as operators of linear transformations. In both cases, the bond-type formalism is developed. The kth non-stochastic and stochastic total linear indices are calculated by adding the kth non-stochastic and stochastic bond linear indices, respectively, of all bonds in molecule. First, the new bond-based molecular descriptors (MDs) are tested for suitability, for the QSPRs, by analyzing regressions of novel indices for selected physicochemical properties of octane isomers (first round). General performance of the new descriptors in this QSPR studies is evaluated with regard to the well-known sets of 2D/3D MDs. From the analysis, we can conclude that the non-stochastic and stochastic bond-based linear indices have an overall good modeling capability proving their usefulness in QSPR studies. Later, the novel bond-level MDs are also used for the description and prediction of the boiling point of 28 alkyl-alcohols (second round), and to the modeling of the specific rate constant (log k), partition coefficient (log P), as well as the antibacterial activity of 34 derivatives of 2-furylethylenes (third round). The comparison with other approaches (edge- and vertices-based connectivity indices, total and local spectral moments, and quantum chemical descriptors as well as E-state/biomolecular encounter parameters) exposes a good behavior of our method in this QSPR studies. Finally, the approach described in this study appears to be a very promising structural invariant, useful not only for QSPR studies but also for similarity/diversity analysis and drug discovery protocols.

  15. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 (Version 2.1) Catchments for the Conterminous United States: GeoChemPhys

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents geochemical or geophysical attributes in surface or near surface geology within individual, local NHDPlusV2 catchments and upstream,...

  16. Visible and Near-Infrared (VNIR) Spectroscopy of Altered Basalts with Application to the ChemCam Library for Mars Science Laboratory

    Science.gov (United States)

    Hadnott, B.; Ehlmann, B. L.

    2012-12-01

    The discovery of Fe, Mg, and Al clays on Mars using VNIR spectroscopy from orbit indicates past low temperature/pressure hydrothermal and weathering environments. Laboratory analysis of Mars-analog rocks from these settings on Earth was used to build the ChemCam sample library for Mars Science Laboratory, permitting for more accurate compositional analysis of Martian samples, improved linkages between VNIR's mineralogic and ChemCam's elemental data, and improved recognition of different environmental settings for aqueous alteration. VNIR spectroscopy was used to analyze 4 suites of altered basaltic rocks—one from San Carlos, AZ and three from various locations in Iceland. Continuum shape and absorption features were found to vary, depending on the environment and extent of alteration. Relatively unaltered rocks had electronic absorptions related to ferrous iron. The strength of the 1.9- μm (μm = microns) H2O absorption correlated with the degree of aqueous alteration. Samples with strong 1.9- μm absorptions often exhibited absorption bands at 1.4, 2.2, and 2.3 μm indicating the presence of clay minerals and/or features at 0.5-0.8 μm indicative of ferric iron oxides. Diagnostic absorption features and continuum slopes have been used to identify a representative subset of rocks from each suite for further analysis for the ChemCam library. Noteworthy spectral features for all suites included variation of absorption bands from 2.0-2.5 μm. Most samples contained an absorption band near 2.21 μm, indicating the presence of Si-OH or Al-OH; a 2.3 μm band is also present in some samples, indicating the presence of Mg-OH and Fe-OH, with subtle shifts between 2.29 and 2.35 μm indicating the major cation and constituent phase (e.g. amorphous phase, smectite or chlorite). Overall continuum slope correlated with the degree of alteration. Flat slopes contained weak 1.9 μm bands (little alteration) and sometimes ferrous iron absorptions of primary minerals. Negative

  17. In situ calibration using univariate analyses based on the onboard ChemCam targets: first prediction of Martian rock and soil compositions

    International Nuclear Information System (INIS)

    Fabre, C.; Cousin, A.; Wiens, R.C.; Ollila, A.; Gasnault, O.; Maurice, S.; Sautter, V.; Forni, O.; Lasue, J.; Tokar, R.; Vaniman, D.; Melikechi, N.

    2014-01-01

    Curiosity rover landed on August 6th, 2012 in Gale Crater, Mars and it possesses unique analytical capabilities to investigate the chemistry and mineralogy of the Martian soil. In particular, the LIBS technique is being used for the first time on another planet with the ChemCam instrument, and more than 75,000 spectra have been returned in the first year on Mars. Curiosity carries body-mounted calibration targets specially designed for the ChemCam instrument, some of which are homgeneous glasses and others that are fine-grained glass-ceramics. We present direct calibrations, using these onboard standards to infer elements and element ratios by ratioing relative peak areas. As the laser spot size is around 300 μm, the LIBS technique provides measurements of the silicate glass compositions representing homogeneous material and measurements of the ceramic targets that are comparable to fine-grained rock or soil. The laser energy and the auto-focus are controlled for all sequences used for calibration. The univariate calibration curves present relatively to very good correlation coefficients with low RSDs for major and ratio calibrations. Trace element calibration curves (Li, Sr, and Mn), down to several ppm, can be used as a rapid tool to draw attention to remarkable rocks and soils along the traverse. First comparisons to alpha-particle X-ray spectroscopy (APXS) data, on selected targets, show good agreement for most elements and for Mg# and Al/Si estimates. SiO 2 estimates using univariate cannot be yet used. Na 2 O and K 2 O estimates are relevant for high alkali contents, but probably under estimated due to the CCCT initial compositions. Very good results for CaO and Al 2 O 3 estimates and satisfactory results for FeO are obtained. - Highlights: • In situ LIBS univariate calibrations are done using the Curiosity onboard standards. • Major and minor element contents can be rapidly obtained. • Trace element contents can be used as a rapid tool along the

  18. In situ calibration using univariate analyses based on the onboard ChemCam targets: first prediction of Martian rock and soil compositions

    Energy Technology Data Exchange (ETDEWEB)

    Fabre, C. [GeoRessources lab, Université de Lorraine, Nancy (France); Cousin, A.; Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Ollila, A. [University of NM, Albuquerque (United States); Gasnault, O.; Maurice, S. [IRAP, Toulouse (France); Sautter, V. [Museum National d' Histoire Naturelle, Paris (France); Forni, O.; Lasue, J. [IRAP, Toulouse (France); Tokar, R.; Vaniman, D. [Planetary Science Institute, Tucson, AZ (United States); Melikechi, N. [Delaware State University (United States)

    2014-09-01

    Curiosity rover landed on August 6th, 2012 in Gale Crater, Mars and it possesses unique analytical capabilities to investigate the chemistry and mineralogy of the Martian soil. In particular, the LIBS technique is being used for the first time on another planet with the ChemCam instrument, and more than 75,000 spectra have been returned in the first year on Mars. Curiosity carries body-mounted calibration targets specially designed for the ChemCam instrument, some of which are homgeneous glasses and others that are fine-grained glass-ceramics. We present direct calibrations, using these onboard standards to infer elements and element ratios by ratioing relative peak areas. As the laser spot size is around 300 μm, the LIBS technique provides measurements of the silicate glass compositions representing homogeneous material and measurements of the ceramic targets that are comparable to fine-grained rock or soil. The laser energy and the auto-focus are controlled for all sequences used for calibration. The univariate calibration curves present relatively to very good correlation coefficients with low RSDs for major and ratio calibrations. Trace element calibration curves (Li, Sr, and Mn), down to several ppm, can be used as a rapid tool to draw attention to remarkable rocks and soils along the traverse. First comparisons to alpha-particle X-ray spectroscopy (APXS) data, on selected targets, show good agreement for most elements and for Mg# and Al/Si estimates. SiO{sub 2} estimates using univariate cannot be yet used. Na{sub 2}O and K{sub 2}O estimates are relevant for high alkali contents, but probably under estimated due to the CCCT initial compositions. Very good results for CaO and Al{sub 2}O{sub 3} estimates and satisfactory results for FeO are obtained. - Highlights: • In situ LIBS univariate calibrations are done using the Curiosity onboard standards. • Major and minor element contents can be rapidly obtained. • Trace element contents can be used as a

  19. Modeling regional air quality and climate: improving organic aerosol and aerosol activation processes in WRF/Chem version 3.7.1

    Science.gov (United States)

    Yahya, Khairunnisa; Glotfelty, Timothy; Wang, Kai; Zhang, Yang; Nenes, Athanasios

    2017-06-01

    Air quality and climate influence each other through the uncertain processes of aerosol formation and cloud droplet activation. In this study, both processes are improved in the Weather, Research and Forecasting model with Chemistry (WRF/Chem) version 3.7.1. The existing Volatility Basis Set (VBS) treatments for organic aerosol (OA) formation in WRF/Chem are improved by considering the following: the secondary OA (SOA) formation from semi-volatile primary organic aerosol (POA), a semi-empirical formulation for the enthalpy of vaporization of SOA, and functionalization and fragmentation reactions for multiple generations of products from the oxidation of VOCs. Over the continental US, 2-month-long simulations (May to June 2010) are conducted and results are evaluated against surface and aircraft observations during the Nexus of Air Quality and Climate Change (CalNex) campaign. Among all the configurations considered, the best performance is found for the simulation with the 2005 Carbon Bond mechanism (CB05) and the VBS SOA module with semivolatile POA treatment, 25 % fragmentation, and the emissions of semi-volatile and intermediate volatile organic compounds being 3 times the original POA emissions. Among the three gas-phase mechanisms (CB05, CB6, and SAPRC07) used, CB05 gives the best performance for surface ozone and PM2. 5 concentrations. Differences in SOA predictions are larger for the simulations with different VBS treatments (e.g., nonvolatile POA versus semivolatile POA) compared to the simulations with different gas-phase mechanisms. Compared to the simulation with CB05 and the default SOA module, the simulations with the VBS treatment improve cloud droplet number concentration (CDNC) predictions (normalized mean biases from -40.8 % to a range of -34.6 to -27.7 %), with large differences between CB05-CB6 and SAPRC07 due to large differences in their OH and HO2 predictions. An advanced aerosol activation parameterization based on the Fountoukis and Nenes

  20. Quantifying sources of elemental carbon over the Guanzhong Basin of China: A consistent network of measurements and WRF-Chem modeling

    International Nuclear Information System (INIS)

    Li, Nan; He, Qingyang; Tie, Xuexi; Cao, Junji; Liu, Suixin; Wang, Qiyuan; Li, Guohui; Huang, Rujin; Zhang, Qiang

    2016-01-01

    We conducted a year-long WRF-Chem (Weather Research and Forecasting Chemical) model simulation of elemental carbon (EC) aerosol and compared the modeling results to the surface EC measurements in the Guanzhong (GZ) Basin of China. The main goals of this study were to quantify the individual contributions of different EC sources to EC pollution, and to find the major cause of the EC pollution in this region. The EC measurements were simultaneously conducted at 10 urban, rural, and background sites over the GZ Basin from May 2013 to April 2014, and provided a good base against which to evaluate model simulation. The model evaluation showed that the calculated annual mean EC concentration was 5.1 μgC m −3 , which was consistent with the observed value of 5.3 μgC m −3 . Moreover, the model result also reproduced the magnitude of measured EC in all seasons (regression slope = 0.98–1.03), as well as the spatial and temporal variations (r = 0.55–0.78). We conducted several sensitivity studies to quantify the individual contributions of EC sources to EC pollution. The sensitivity simulations showed that the local and outside sources contributed about 60% and 40% to the annual mean EC concentration, respectively, implying that local sources were the major EC pollution contributors in the GZ Basin. Among the local sources, residential sources contributed the most, followed by industry and transportation sources. A further analysis suggested that a 50% reduction of industry or transportation emissions only caused a 6% decrease in the annual mean EC concentration, while a 50% reduction of residential emissions reduced the winter surface EC concentration by up to 25%. In respect to the serious air pollution problems (including EC pollution) in the GZ Basin, our findings can provide an insightful view on local air pollution control strategies. - Highlights: • A yearlong WRF-Chem simulation is conducted to identify sources of the EC pollution. • A network of

  1. Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

    Directory of Open Access Journals (Sweden)

    A. Vara-Vela

    2016-01-01

    Full Text Available The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter in the Sao Paulo Metropolitan Area (SPMA in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012 to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the

  2. Accounting for model error in air quality forecasts: an application of 4DEnVar to the assimilation of atmospheric composition using QG-Chem 1.0

    Directory of Open Access Journals (Sweden)

    E. Emili

    2016-11-01

    Full Text Available Model errors play a significant role in air quality forecasts. Accounting for them in the data assimilation (DA procedures is decisive to obtain improved forecasts. We address this issue using a reduced-order coupled chemistry–meteorology model based on quasi-geostrophic dynamics and a detailed tropospheric chemistry mechanism, which we name QG-Chem. This model has been coupled to the software library for the data assimilation Object Oriented Prediction System (OOPS and used to assess the potential of the 4DEnVar algorithm for air quality analyses and forecasts. The assets of 4DEnVar include the possibility to deal with multivariate aspects of atmospheric chemistry and to account for model errors of a generic type. A simple diagnostic procedure for detecting model errors is proposed, based on the 4DEnVar analysis and one additional model forecast. A large number of idealized data assimilation experiments are shown for several chemical species of relevance for air quality forecasts (O3, NOx, CO and CO2 with very different atmospheric lifetimes and chemical couplings. Experiments are done both under a perfect model hypothesis and including model error through perturbation of surface chemical emissions. Some key elements of the 4DEnVar algorithm such as the ensemble size and localization are also discussed. A comparison with results of 3D-Var, widely used in operational centers, shows that, for some species, analysis and next-day forecast errors can be halved when model error is taken into account. This result was obtained using a small ensemble size, which remains affordable for most operational centers. We conclude that 4DEnVar has a promising potential for operational air quality models. We finally highlight areas that deserve further research for applying 4DEnVar to large-scale chemistry models, i.e., localization techniques, propagation of analysis covariance between DA cycles and treatment for chemical nonlinearities. QG-Chem can provide a

  3. Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

    Science.gov (United States)

    Vara-Vela, A.; Andrade, M. F.; Kumar, P.; Ynoue, R. Y.; Muñoz, A. G.

    2016-01-01

    The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August-6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40-50 % of the total PM10 (i.e. those ≤ 10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the

  4. Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

    Science.gov (United States)

    Abou Rafee, Sameh A.; Martins, Leila D.; Kawashima, Ana B.; Almeida, Daniela S.; Morais, Marcos V. B.; Souza, Rita V. A.; Oliveira, Maria B. L.; Souza, Rodrigo A. F.; Medeiros, Adan S. S.; Urbina, Viviana; Freitas, Edmilson D.; Martin, Scot T.; Martins, Jorge A.

    2017-06-01

    This paper evaluates the contributions of the emissions from mobile, stationary and biogenic sources on air pollution in the Amazon rainforest by using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. The analyzed air pollutants were CO, NOx, SO2, O3, PM2. 5, PM10 and volatile organic compounds (VOCs). Five scenarios were defined in order to evaluate the emissions by biogenic, mobile and stationary sources, as well as a future scenario to assess the potential air quality impact of doubled anthropogenic emissions. The stationary sources explain the highest concentrations for all air pollutants evaluated, except for CO, for which the mobile sources are predominant. The anthropogenic sources considered resulted an increasing in the spatial peak-temporal average concentrations of pollutants in 3 to 2780 times in relation to those with only biogenic sources. The future scenario showed an increase in the range of 3 to 62 % in average concentrations and 45 to 109 % in peak concentrations depending on the pollutant. In addition, the spatial distributions of the scenarios has shown that the air pollution plume from the city of Manaus is predominantly transported west and southwest, and it can reach hundreds of kilometers in length.

  5. Application of a coupled ecosystem-chemical equilibrium model, DayCent-Chem, to stream and soil chemistry in a Rocky Mountain watershed

    Science.gov (United States)

    Hartman, M.D.; Baron, Jill S.; Ojima, D.S.

    2007-01-01

    Atmospheric deposition of sulfur and nitrogen species have the potential to acidify terrestrial and aquatic ecosystems, but nitrate and ammonium are also critical nutrients for plant and microbial productivity. Both the ecological response and the hydrochemical response to atmospheric deposition are of interest to regulatory and land management agencies. We developed a non-spatial biogeochemical model to simulate soil and surface water chemistry by linking the daily version of the CENTURY ecosystem model (DayCent) with a low temperature aqueous geochemical model, PHREEQC. The coupled model, DayCent-Chem, simulates the daily dynamics of plant production, soil organic matter, cation exchange, mineral weathering, elution, stream discharge, and solute concentrations in soil water and stream flow. By aerially weighting the contributions of separate bedrock/talus and tundra simulations, the model was able to replicate the measured seasonal and annual stream chemistry for most solutes for Andrews Creek in Loch Vale watershed, Rocky Mountain National Park. Simulated soil chemistry, net primary production, live biomass, and soil organic matter for forest and tundra matched well with measurements. This model is appropriate for accurately describing ecosystem and surface water chemical response to atmospheric deposition and climate change. ?? 2006 Elsevier B.V. All rights reserved.

  6. Sensitivity of CAM-Chem/DART MOPITT CO Assimilation Performance to the Choice of Ensemble System Configuration: A Case Study for Fires in the Amazon

    Science.gov (United States)

    Arellano, A. F., Jr.; Tang, W.

    2017-12-01

    Assimilating observational data of chemical constituents into a modeling system is a powerful approach in assessing changes in atmospheric composition and estimating associated emissions. However, the results of such chemical data assimilation (DA) experiments are largely subject to various key factors such as: a) a priori information, b) error specification and representation, and c) structural biases in the modeling system. Here we investigate the sensitivity of an ensemble-based data assimilation state and emission estimates to these key factors. We focus on investigating the assimilation performance of the Community Earth System Model (CESM)/CAM-Chem with the Data Assimilation Research Testbed (DART) in representing biomass burning plumes in the Amazonia during the 2008 fire season. We conduct the following ensemble DA MOPITT CO experiments: 1) use of monthly-average NCAR's FINN surface fire emissionss, 2) use of daily FINN surface fire emissions, 3) use of daily FINN emissions with climatological injection heights, and 4) use of perturbed FINN emission parameters to represent not only the uncertainties in combustion activity but also in combustion efficiency. We show key diagnostics of assimilation performance for these experiments and verify with available ground-based and aircraft-based measurements.

  7. Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

    Directory of Open Access Journals (Sweden)

    S. A. Abou Rafee

    2017-06-01

    Full Text Available This paper evaluates the contributions of the emissions from mobile, stationary and biogenic sources on air pollution in the Amazon rainforest by using the Weather Research and Forecasting with Chemistry (WRF-Chem model. The analyzed air pollutants were CO, NOx, SO2, O3, PM2. 5, PM10 and volatile organic compounds (VOCs. Five scenarios were defined in order to evaluate the emissions by biogenic, mobile and stationary sources, as well as a future scenario to assess the potential air quality impact of doubled anthropogenic emissions. The stationary sources explain the highest concentrations for all air pollutants evaluated, except for CO, for which the mobile sources are predominant. The anthropogenic sources considered resulted an increasing in the spatial peak-temporal average concentrations of pollutants in 3 to 2780 times in relation to those with only biogenic sources. The future scenario showed an increase in the range of 3 to 62 % in average concentrations and 45 to 109 % in peak concentrations depending on the pollutant. In addition, the spatial distributions of the scenarios has shown that the air pollution plume from the city of Manaus is predominantly transported west and southwest, and it can reach hundreds of kilometers in length.

  8. Mitigating Satellite-Based Fire Sampling Limitations in Deriving Biomass Burning Emission Rates: Application to WRF-Chem Model Over the Northern sub-Saharan African Region

    Science.gov (United States)

    Wang, Jun; Yue, Yun; Wang, Yi; Ichoku, Charles; Ellison, Luke; Zeng, Jing

    2018-01-01

    Largely used in several independent estimates of fire emissions, fire products based on MODIS sensors aboard the Terra and Aqua polar-orbiting satellites have a number of inherent limitations, including (a) inability to detect fires below clouds, (b) significant decrease of detection sensitivity at the edge of scan where pixel sizes are much larger than at nadir, and (c) gaps between adjacent swaths in tropical regions. To remedy these limitations, an empirical method is developed here and applied to correct fire emission estimates based on MODIS pixel level fire radiative power measurements and emission coefficients from the Fire Energetics and Emissions Research (FEER) biomass burning emission inventory. The analysis was performed for January 2010 over the northern sub-Saharan African region. Simulations from WRF-Chem model using original and adjusted emissions are compared with the aerosol optical depth (AOD) products from MODIS and AERONET as well as aerosol vertical profile from CALIOP data. The comparison confirmed an 30-50% improvement in the model simulation performance (in terms of correlation, bias, and spatial pattern of AOD with respect to observations) by the adjusted emissions that not only increases the original emission amount by a factor of two but also results in the spatially continuous estimates of instantaneous fire emissions at daily time scales. Such improvement cannot be achieved by simply scaling the original emission across the study domain. Even with this improvement, a factor of two underestimations still exists in the modeled AOD, which is within the current global fire emissions uncertainty envelope.

  9. In vivo identical reversibility of rad-bio-chem lesions in blood, bone marrow, liver, endocrine system and on the whole body

    International Nuclear Information System (INIS)

    Stan, C.

    2009-01-01

    The fundamental scientific researches of a new patented pharmaceutical product STANOSIMAGNE, was initiated, directed and developed since 1995, as interdisciplinary challenge for in vivo decorporation on natural way of radio-toxic uranium (235U) and radionuclides, and the treatment of lesions induced by radiation injury, or heavy metals. The synergic effect - decorporation and reversibility - for in vivo identical reversibility of rad-bio-chem lesions in blood, bone marrow, liver, endocrine system, derma and vital organs verifies and sustains the scientific discovery. The safety and efficiency of clinical administration of the medicine STANOSIMAGNE capsules and ointment is based on the non-clinic (pre-clinic) practical pharmacological research on 635 standard laboratory animals regarding the absence of any kind of toxicity. The pharmacology researches have been carried out, along with medical, pharmaceutical and biochemical didactic specialists, coming from the Laboratories Departments of Pharmacology, Phytochemistry, Biochemistry, Chemistry and Pharmaceutical Technique of the University of Medicine and Pharmacy 'Carol Davila', Bucharest. The treatment of the persons exposed to irradiation or heavy metals contamination, in risk areas, and the continuation of the pilot clinical studies on several cases, that could not be solved by regular medical methods and treatments, are in accordance with the Directive 2001/20/CE, of the Parliament of the European Union, which implement the norms of good practice, in clinical studies.(author)

  10. Chem-Prep PZT 95/5 for Neutron Generator Applications: Particle Size Distribution Comparison of Development and Production-Scale Powders

    International Nuclear Information System (INIS)

    SIPOLA, DIANA L.; VOIGT, JAMES A.; LOCKWOOD, STEVEN J.; RODMAN-GONZALES, EMILY D.

    2002-01-01

    The Materials Chemistry Department 1846 has developed a lab-scale chem-prep process for the synthesis of PNZT 95/5, a ferroelectric material that is used in neutron generator power supplies. This process (Sandia Process, or SP) has been successfully transferred to and scaled by Department 14192 (Ceramics and Glass Department), (Transferred Sandia Process, or TSP), to meet the future supply needs of Sandia for its neutron generator production responsibilities. In going from the development-size SP batch (1.6 kg/batch) to the production-scale TSP powder batch size (10 kg/batch), it was important that it be determined if the scaling process caused any ''performance-critical'' changes in the PNZT 95/5 being produced. One area where a difference was found was in the particle size distributions of the calcined PNZT powders. Documented in this SAND report are the results of an experimental study to determine the origin of the differences in the particle size distribution of the SP and TSP powders

  11. Surface Pressure Dependencies in the GEOS-Chem-Adjoint System and the Impact of the GEOS-5 Surface Pressure on CO2 Model Forecast

    Science.gov (United States)

    Lee, Meemong; Weidner, Richard

    2016-01-01

    In the GEOS-Chem Adjoint (GCA) system, the total (wet) surface pressure of the GEOS meteorology is employed as dry surface pressure, ignoring the presence of water vapor. The Jet Propulsion Laboratory (JPL) Carbon Monitoring System (CMS) research team has been evaluating the impact of the above discrepancy on the CO2 model forecast and the CO2 flux inversion. The JPL CMS research utilizes a multi-mission assimilation framework developed by the Multi-Mission Observation Operator (M2O2) research team at JPL extending the GCA system. The GCA-M2O2 framework facilitates mission-generic 3D and 4D-variational assimilations streamlining the interfaces to the satellite data products and prior emission inventories. The GCA-M2O2 framework currently integrates the GCA system version 35h and provides a dry surface pressure setup to allow the CO2 model forecast to be performed with the GEOS-5 surface pressure directly or after converting it to dry surface pressure.

  12. Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe - Part 1: Model description, evaluation of meteorological predictions, and aerosol-meteorology interactions

    Science.gov (United States)

    Zhang, Y.; Sartelet, K.; Wu, S.-Y.; Seigneur, C.

    2013-07-01

    Comprehensive model evaluation and comparison of two 3-D air quality modeling systems (i.e., the Weather Research and Forecast model (WRF)/Polyphemus and WRF with chemistry and the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) (WRF/Chem-MADRID)) are conducted over Western Europe. Part 1 describes the background information for the model comparison and simulation design, the application of WRF for January and July 2001 over triple-nested domains in Western Europe at three horizontal grid resolutions: 0.5°, 0.125°, and 0.025°, and the effect of aerosol/meteorology interactions on meteorological predictions. Nine simulated meteorological variables (i.e., downward shortwave and longwave radiation fluxes (SWDOWN and LWDOWN), outgoing longwave radiation flux (OLR), temperature at 2 m (T2), specific humidity at 2 m (Q2), relative humidity at 2 m (RH2), wind speed at 10 m (WS10), wind direction at 10 m (WD10), and precipitation (Precip)) are evaluated using available observations in terms of spatial distribution, domainwide daily and site-specific hourly variations, and domainwide performance statistics. The vertical profiles of temperature, dew points, and wind speed/direction are also evaluated using sounding data. WRF demonstrates its capability in capturing diurnal/seasonal variations and spatial gradients and vertical profiles of major meteorological variables. While the domainwide performance of LWDOWN, OLR, T2, Q2, and RH2 at all three grid resolutions is satisfactory overall, large positive or negative biases occur in SWDOWN, WS10, and Precip even at 0.125° or 0.025° in both months and in WD10 in January. In addition, discrepancies between simulations and observations exist in T2, Q2, WS10, and Precip at mountain/high altitude sites and large urban center sites in both months, in particular, during snow events or thunderstorms. These results indicate the model's difficulty in capturing meteorological variables in complex terrain and

  13. Modeling regional air quality and climate: improving organic aerosol and aerosol activation processes in WRF/Chem version 3.7.1

    Directory of Open Access Journals (Sweden)

    K. Yahya

    2017-06-01

    Full Text Available Air quality and climate influence each other through the uncertain processes of aerosol formation and cloud droplet activation. In this study, both processes are improved in the Weather, Research and Forecasting model with Chemistry (WRF/Chem version 3.7.1. The existing Volatility Basis Set (VBS treatments for organic aerosol (OA formation in WRF/Chem are improved by considering the following: the secondary OA (SOA formation from semi-volatile primary organic aerosol (POA, a semi-empirical formulation for the enthalpy of vaporization of SOA, and functionalization and fragmentation reactions for multiple generations of products from the oxidation of VOCs. Over the continental US, 2-month-long simulations (May to June 2010 are conducted and results are evaluated against surface and aircraft observations during the Nexus of Air Quality and Climate Change (CalNex campaign. Among all the configurations considered, the best performance is found for the simulation with the 2005 Carbon Bond mechanism (CB05 and the VBS SOA module with semivolatile POA treatment, 25 % fragmentation, and the emissions of semi-volatile and intermediate volatile organic compounds being 3 times the original POA emissions. Among the three gas-phase mechanisms (CB05, CB6, and SAPRC07 used, CB05 gives the best performance for surface ozone and PM2. 5 concentrations. Differences in SOA predictions are larger for the simulations with different VBS treatments (e.g., nonvolatile POA versus semivolatile POA compared to the simulations with different gas-phase mechanisms. Compared to the simulation with CB05 and the default SOA module, the simulations with the VBS treatment improve cloud droplet number concentration (CDNC predictions (normalized mean biases from −40.8 % to a range of −34.6 to −27.7 %, with large differences between CB05–CB6 and SAPRC07 due to large differences in their OH and HO2 predictions. An advanced aerosol activation

  14. Contributions of foreign, domestic and natural emissions to US ozone estimated using the path-integral method in CAMx nested within GEOS-Chem

    Directory of Open Access Journals (Sweden)

    A. M. Dunker

    2017-10-01

    Full Text Available The Goddard Earth Observing System global chemical transport (GEOS-Chem model was used at 2°  ×  2.5° resolution to simulate ozone formation for a base case representing year 2010 and a natural background case without worldwide anthropogenic emissions. These simulations provided boundary concentrations for base and natural background simulations with the Comprehensive Air Quality Model with Extensions (CAMx on a North American domain (one-way nested at 12 km  ×  12 km resolution over March–September 2010. The predicted maximum daily average 8 h (MDA8 background ozone for the US is largest in the mountainous areas of Colorado, New Mexico, Arizona, and California. The background MDA8 ozone in some of these locations exceeds 60 ppb, when averaged over the 10 days with the largest base-case ozone (T10base average. The background ozone generally becomes both a larger fraction of the base-case ozone in the western US and a smaller fraction in the eastern US when proceeding from spring to summer to the T10base average. The ozone difference between the base and background cases represents the increment to ozone from all anthropogenic sources. The path-integral method was applied to allocate this anthropogenic ozone increment to US anthropogenic emissions, Canadian/Mexican anthropogenic emissions, and the anthropogenic components of the lateral and top boundary concentrations (BCs. Using the T10base average MDA8 ozone, the relative importance of the sources is generally US emissions  >  anthropogenic lateral BCs  >  Canadian/Mexican emissions  ≫  anthropogenic top BCs. Specifically, for 10 US urban areas, the source contributions were 12–53 ppb for US emissions, 3–9 ppb for lateral BCs, 0.2–3 ppb for Canadian/Mexican emissions, and  ≤  0.1 ppb for top BCs. The contributions of the lateral BCs are largest for the higher-elevation US sites in the Intermountain West and along the

  15. Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe – Part 1: Model description, evaluation of meteorological predictions, and aerosol–meteorology interactions

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2013-07-01

    Full Text Available Comprehensive model evaluation and comparison of two 3-D air quality modeling systems (i.e., the Weather Research and Forecast model (WRF/Polyphemus and WRF with chemistry and the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID (WRF/Chem-MADRID are conducted over Western Europe. Part 1 describes the background information for the model comparison and simulation design, the application of WRF for January and July 2001 over triple-nested domains in Western Europe at three horizontal grid resolutions: 0.5°, 0.125°, and 0.025°, and the effect of aerosol/meteorology interactions on meteorological predictions. Nine simulated meteorological variables (i.e., downward shortwave and longwave radiation fluxes (SWDOWN and LWDOWN, outgoing longwave radiation flux (OLR, temperature at 2 m (T2, specific humidity at 2 m (Q2, relative humidity at 2 m (RH2, wind speed at 10 m (WS10, wind direction at 10 m (WD10, and precipitation (Precip are evaluated using available observations in terms of spatial distribution, domainwide daily and site-specific hourly variations, and domainwide performance statistics. The vertical profiles of temperature, dew points, and wind speed/direction are also evaluated using sounding data. WRF demonstrates its capability in capturing diurnal/seasonal variations and spatial gradients and vertical profiles of major meteorological variables. While the domainwide performance of LWDOWN, OLR, T2, Q2, and RH2 at all three grid resolutions is satisfactory overall, large positive or negative biases occur in SWDOWN, WS10, and Precip even at 0.125° or 0.025° in both months and in WD10 in January. In addition, discrepancies between simulations and observations exist in T2, Q2, WS10, and Precip at mountain/high altitude sites and large urban center sites in both months, in particular, during snow events or thunderstorms. These results indicate the model's difficulty in capturing meteorological variables in complex

  16. Sensitivity of simulated convection-driven stratosphere-troposphere exchange in WRF-Chem to the choice of physical and chemical parameterization

    Science.gov (United States)

    Phoenix, Daniel B.; Homeyer, Cameron R.; Barth, Mary C.

    2017-08-01

    Tropopause-penetrating convection is capable of rapidly transporting air from the lower troposphere to the upper troposphere and lower stratosphere (UTLS), where it can have important impacts on chemistry, the radiative budget, and climate. However, obtaining in situ measurements of convection and convective transport is difficult and such observations are historically rare. Modeling studies, on the other hand, offer the advantage of providing output related to the physical, dynamical, and chemical characteristics of storms and their environments at fine spatial and temporal scales. Since these characteristics of simulated convection depend on the chosen model design, we examine the sensitivity of simulated convective transport to the choice of physical (bulk microphysics or BMP and planetary boundary layer or PBL) and chemical parameterizations in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). In particular, we simulate multiple cases where in situ observations are available from the recent (2012) Deep Convective Clouds and Chemistry (DC3) experiment. Model output is evaluated using ground-based radar observations of each storm and in situ trace gas observations from two aircraft operated during the DC3 experiment. Model results show measurable sensitivity of the physical characteristics of a storm and the transport of water vapor and additional trace gases into the UTLS to the choice of BMP. The physical characteristics of the storm and transport of insoluble trace gases are largely insensitive to the choice of PBL scheme and chemical mechanism, though several soluble trace gases (e.g., SO2, CH2O, and HNO3) exhibit some measurable sensitivity.

  17. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    Directory of Open Access Journals (Sweden)

    B. Franco

    2015-04-01

    Full Text Available As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs, formaldehyde (HCHO plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.. Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs, GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  18. WRF-Chem simulated surface ozone over south Asia during the pre-monsoon: effects of emission inventories and chemical mechanisms

    Directory of Open Access Journals (Sweden)

    A. Sharma

    2017-12-01

    Full Text Available We evaluate numerical simulations of surface ozone mixing ratios over the south Asian region during the pre-monsoon season, employing three different emission inventories in the Weather Research and Forecasting model with Chemistry (WRF-Chem with the second-generation Regional Acid Deposition Model (RADM2 chemical mechanism: the Emissions Database for Global Atmospheric Research – Hemispheric Transport of Air Pollution (EDGAR-HTAP, the Intercontinental Chemical Transport Experiment phase B (INTEX-B and the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS. Evaluation of diurnal variability in modelled ozone compared to observational data from 15 monitoring stations across south Asia shows the model ability to reproduce the clean, rural and polluted urban conditions over this region. In contrast to the diurnal average, the modelled ozone mixing ratios during noontime, i.e. hours of intense photochemistry (11:30–16:30 IST – Indian Standard Time – UTC +5:30, are found to differ among the three inventories. This suggests that evaluations of the modelled ozone limited to 24 h average are insufficient to assess uncertainties associated with ozone buildup. HTAP generally shows 10–30 ppbv higher noontime ozone mixing ratios than SEAC4RS and INTEX-B, especially over the north-west Indo-Gangetic Plain (IGP, central India and southern India. The HTAP simulation repeated with the alternative Model for Ozone and Related Chemical Tracers (MOZART chemical mechanism showed even more strongly enhanced surface ozone mixing ratios due to vertical mixing of enhanced ozone that has been produced aloft. Our study indicates the need to also evaluate the O3 precursors across a network of stations and the development of high-resolution regional inventories for the anthropogenic emissions over south Asia accounting for year-to-year changes to further reduce uncertainties in modelled ozone over this region.

  19. A WRF/Chem sensitivity study using ensemble modelling for a high ozone episode in Slovenia and the Northern Adriatic area

    Science.gov (United States)

    Žabkar, Rahela; Koračin, Darko; Rakovec, Jože

    2013-10-01

    A high ozone (O3) concentrations episode during a heat wave event in the Northeastern Mediterranean was investigated using the WRF/Chem model. To understand the major model uncertainties and errors as well as the impacts of model inputs on the model accuracy, an ensemble modelling experiment was conducted. The 51-member ensemble was designed by varying model physics parameterization options (PBL schemes with different surface layer and land-surface modules, and radiation schemes); chemical initial and boundary conditions; anthropogenic and biogenic emission inputs; and model domain setup and resolution. The main impacts of the geographical and emission characteristics of three distinct regions (suburban Mediterranean, continental urban, and continental rural) on the model accuracy and O3 predictions were investigated. In spite of the large ensemble set size, the model generally failed to simulate the extremes; however, as expected from probabilistic forecasting the ensemble spread improved results with respect to extremes compared to the reference run. Noticeable model nighttime overestimations at the Mediterranean and some urban and rural sites can be explained by too strong simulated winds, which reduce the impact of dry deposition and O3 titration in the near surface layers during the nighttime. Another possible explanation could be inaccuracies in the chemical mechanisms, which are suggested also by model insensitivity to variations in the nitrogen oxides (NOx) and volatile organic compounds (VOC) emissions. Major impact factors for underestimations of the daytime O3 maxima at the Mediterranean and some rural sites include overestimation of the PBL depths, a lack of information on forest fires, too strong surface winds, and also possible inaccuracies in biogenic emissions. This numerical experiment with the ensemble runs also provided guidance on an optimum model setup and input data.

  20. Coupling spectral-bin cloud microphysics with the MOSAIC aerosol model in WRF-Chem: Methodology and results for marine stratocumulus clouds

    Science.gov (United States)

    Gao, Wenhua; Fan, Jiwen; Easter, R. C.; Yang, Qing; Zhao, Chun; Ghan, Steven J.

    2016-09-01

    Aerosol-cloud interaction processes can be represented more physically with bin cloud microphysics relative to bulk microphysical parameterizations. However, due to computational power limitations in the past, bin cloud microphysics was often run with very simple aerosol treatments. The purpose of this study is to represent better aerosol-cloud interaction processes in the Chemistry version of Weather Research and Forecast model (WRF-Chem) at convection-permitting scales by coupling spectral-bin cloud microphysics (SBM) with the MOSAIC sectional aerosol model. A flexible interface is built that exchanges cloud and aerosol information between them. The interface contains a new bin aerosol activation approach, which replaces the treatments in the original SBM. It also includes the modified aerosol resuspension and in-cloud wet removal processes with the droplet loss tendencies and precipitation fluxes from SBM. The newly coupled system is evaluated for two marine stratocumulus cases over the Southeast Pacific Ocean with either a simplified aerosol setup or full-chemistry. We compare the aerosol activation process in the newly coupled SBM-MOSAIC against the SBM simulation without chemistry using a simplified aerosol setup, and the results show consistent activation rates. A longer time simulation reinforces that aerosol resuspension through cloud drop evaporation plays an important role in replenishing aerosols and impacts cloud and precipitation in marine stratocumulus clouds. Evaluation of the coupled SBM-MOSAIC with full-chemistry using aircraft measurements suggests that the new model works realistically for the marine stratocumulus clouds, and improves the simulation of cloud microphysical properties compared to a simulation using MOSAIC coupled with the Morrison two-moment microphysics.

  1. Benchmarking of AREVA BWR FDIC-PEZOG model against first BFE3 cycle 15 application of On-Line NobleChem results

    International Nuclear Information System (INIS)

    Pop, M.G.; Lamanna, L.S.; Hoornik, A.; Storey, G.C.; Lemons, J.F.

    2015-01-01

    The combination of AREVA's BWR FDIC-PEZOG tools allows the calculation of the total liftoff as a measure of fuel performance and a risk indicator for fuel reliability. The AREVA BWR FDIC tool is a crud modeling tool. The PEZOG tool models the platinum-enhanced zirconium oxide growth of fuel cladding when exposed to platinum during operation. Continuous effort to improve these tools used for the total liftoff calculations is illustrated by the benchmarking of the tools after the application of On-Line NobleChem TM at TVA Browns Ferry Unit 3 during Cycle 15. A set of runs using the modified FDIC-PEZOG model and actual plant water chemistry for Cycle 15 and partial data for Cycle 16 were performed. The updated results' deposit thickness and deposit composition predictions for EOC15 were compared to the measured data from EOC15 and are presented in this paper. The updated predicted deposit thickness matched the actual, measured value exactly. Predicted deposit composition near the fuel rod boundary, nearer to the bulk reactor water, and as an averaged deposit, as presented in the paper, compared extremely well with the measured data at EOC15. The updated AREVA methodology resulted in lower fuel oxide thickness predictions over the life of the fuel as compared to the initial evaluations for BFE3 by incorporating more recent experimental data on the thermal conductivity of zirconia; unnecessary conservatism in the prediction of the fuel oxide thickness over the life of the fuel was removed in the improved model. (authors)

  2. WRF-Chem simulated surface ozone over south Asia during the pre-monsoon: effects of emission inventories and chemical mechanisms

    Science.gov (United States)

    Sharma, Amit; Ojha, Narendra; Pozzer, Andrea; Mar, Kathleen A.; Beig, Gufran; Lelieveld, Jos; Gunthe, Sachin S.

    2017-12-01

    We evaluate numerical simulations of surface ozone mixing ratios over the south Asian region during the pre-monsoon season, employing three different emission inventories in the Weather Research and Forecasting model with Chemistry (WRF-Chem) with the second-generation Regional Acid Deposition Model (RADM2) chemical mechanism: the Emissions Database for Global Atmospheric Research - Hemispheric Transport of Air Pollution (EDGAR-HTAP), the Intercontinental Chemical Transport Experiment phase B (INTEX-B) and the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS). Evaluation of diurnal variability in modelled ozone compared to observational data from 15 monitoring stations across south Asia shows the model ability to reproduce the clean, rural and polluted urban conditions over this region. In contrast to the diurnal average, the modelled ozone mixing ratios during noontime, i.e. hours of intense photochemistry (11:30-16:30 IST - Indian Standard Time - UTC +5:30), are found to differ among the three inventories. This suggests that evaluations of the modelled ozone limited to 24 h average are insufficient to assess uncertainties associated with ozone buildup. HTAP generally shows 10-30 ppbv higher noontime ozone mixing ratios than SEAC4RS and INTEX-B, especially over the north-west Indo-Gangetic Plain (IGP), central India and southern India. The HTAP simulation repeated with the alternative Model for Ozone and Related Chemical Tracers (MOZART) chemical mechanism showed even more strongly enhanced surface ozone mixing ratios due to vertical mixing of enhanced ozone that has been produced aloft. Our study indicates the need to also evaluate the O3 precursors across a network of stations and the development of high-resolution regional inventories for the anthropogenic emissions over south Asia accounting for year-to-year changes to further reduce uncertainties in modelled ozone over this region.

  3. Comment on "Revisiting the definition of local hardness and hardness kernel" by C. A. Polanco-Ramirez, M. Franco-Pérez, J. Carmona-Espíndola, J. L. Gázquez and P. W. Ayers, Phys. Chem. Chem. Phys., 2017, 19, 12355.

    Science.gov (United States)

    Guégan, F; Lamine, W; Chermette, H; Morell, C

    2018-03-28

    In a recent article Polanco-Ramirez et al. proposed new definitions of local chemical potential and local hardness starting from the first derivative of the energy with respect to the number of electrons and a smart use of the chain rule. In this comment we show that this derivation appears naturally in the Taylor expansion of the energy, showing that the construction of Polanco-Ramirez et al. is not artificially built.

  4. Application of Weather Research and Forecasting Model with Chemistry (WRF/Chem) over northern China: Sensitivity study, comparative evaluation, and policy implications

    Science.gov (United States)

    Wang, Litao; Zhang, Yang; Wang, Kai; Zheng, Bo; Zhang, Qiang; Wei, Wei

    2016-01-01

    An extremely severe and persistent haze event occurred over the middle and eastern China in January 2013, with the record-breaking high concentrations of fine particulate matter (PM2.5). In this study, an online-coupled meteorology-air quality model, the Weather Research and Forecasting Model with Chemistry (WRF/Chem), is applied to simulate this pollution episode over East Asia and northern China at 36- and 12-km grid resolutions. A number of simulations are conducted to examine the sensitivities of the model predictions to various physical schemes. The results show that all simulations give similar predictions for temperature, wind speed, wind direction, and humidity, but large variations exist in the prediction for precipitation. The concentrations of PM2.5, particulate matter with aerodynamic diameter of 10 μm or less (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2) are overpredicted partially due to the lack of wet scavenging by the chemistry-aerosol option with the 1999 version of the Statewide Air Pollution Research Center (SAPRC-99) mechanism with the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and the Volatility Basis Set (VBS) for secondary organic aerosol formation. The optimal set of configurations with the best performance is the simulation with the Gorddard shortwave and RRTM longwave radiation schemes, the Purdue Lin microphysics scheme, the Kain-Fritsch cumulus scheme, and a nudging coefficient of 1 × 10-5 for water vapor mixing ratio. The emission sensitivity simulations show that the PM2.5 concentrations are most sensitive to nitrogen oxide (NOx) and SO2 emissions in northern China, but to NOx and ammonia (NH3) emissions in southern China. 30% NOx emission reductions may result in an increase in PM2.5 concentrations in northern China because of the NH3-rich and volatile organic compound (VOC) limited conditions over this area. VOC emission reductions will lead to a decrease in PM2.5 concentrations in eastern China

  5. Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe - Part 1: Model description and evaluation of meteorological predictions

    Science.gov (United States)

    Zhang, Y.; Sartelet, K.; Wu, S.-Y.; Seigneur, C.

    2013-02-01

    Comprehensive model evaluation and comparison of two 3-D air quality modeling systems (i.e. the Weather Research and Forecast model (WRF)/Polyphemus and WRF with chemistry and the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) (WRF/Chem-MADRID) are conducted over western Europe. Part 1 describes the background information for the model comparison and simulation design, as well as the application of WRF for January and July 2001 over triple-nested domains in western Europe at three horizontal grid resolutions: 0.5°, 0.125°, and 0.025°. Six simulated meteorological variables (i.e. temperature at 2 m (T2), specific humidity at 2 m (Q2), relative humidity at 2 m (RH2), wind speed at 10 m (WS10), wind direction at 10 m (WD10), and precipitation (Precip)) are evaluated using available observations in terms of spatial distribution, domainwide daily and site-specific hourly variations, and domainwide performance statistics. WRF demonstrates its capability in capturing diurnal/seasonal variations and spatial gradients of major meteorological variables. While the domainwide performance of T2, Q2, RH2, and WD10 at all three grid resolutions is satisfactory overall, large positive or negative biases occur in WS10 and Precip even at 0.025°. In addition, discrepancies between simulations and observations exist in T2, Q2, WS10, and Precip at mountain/high altitude sites and large urban center sites in both months, in particular, during snow events or thunderstorms. These results indicate the model's difficulty in capturing meteorological variables in complex terrain and subgrid-scale meteorological phenomena, due to inaccuracies in model initialization parameterization (e.g. lack of soil temperature and moisture nudging), limitations in the physical parameterizations of the planetary boundary layer (e.g. cloud microphysics, cumulus parameterizations, and ice nucleation treatments) as well as limitations in surface heat and moisture budget

  6. Inverse modeling and mapping US air quality influences of inorganic PM2.5 precursor emissions using the adjoint of GEOS-Chem

    Science.gov (United States)

    Henze, D. K.; Seinfeld, J. H.; Shindell, D. T.

    2009-08-01

    Influences of specific sources of inorganic PM2.5 on peak and ambient aerosol concentrations in the US are evaluated using a combination of inverse modeling and sensitivity analysis. First, sulfate and nitrate aerosol measurements from the IMPROVE network are assimilated using the four-dimensional variational (4D-Var) method into the GEOS-Chem chemical transport model in order to constrain emissions estimates in four separate month-long inversions (one per season). Of the precursor emissions, these observations primarily constrain ammonia (NH3). While the net result is a decrease in estimated US~NH3 emissions relative to the original inventory, there is considerable variability in adjustments made to NH3 emissions in different locations, seasons and source sectors, such as focused decreases in the midwest during July, broad decreases throughout the US~in January, increases in eastern coastal areas in April, and an effective redistribution of emissions from natural to anthropogenic sources. Implementing these constrained emissions, the adjoint model is applied to quantify the influences of emissions on representative PM2.5 air quality metrics within the US. The resulting sensitivity maps display a wide range of spatial, sectoral and seasonal variability in the susceptibility of the air quality metrics to absolute emissions changes and the effectiveness of incremental emissions controls of specific source sectors. NH3 emissions near sources of sulfur oxides (SOx) are estimated to most influence peak inorganic PM2.5 levels in the East; thus, the most effective controls of NH3 emissions are often disjoint from locations of peak NH3 emissions. Controls of emissions from industrial sectors of SOx and NOx are estimated to be more effective than surface emissions, and changes to NH3 emissions in regions dominated by natural sources are disproportionately more effective than regions dominated by anthropogenic sources. NOx controls are most effective in northern states in

  7. Anthropogenic and volcanic emission impacts on SO2 dynamics and acid rain profiles. Numerical study using WRF-Chem in a high-resolution modeling

    Science.gov (United States)

    Vela, A. V.; González, C. M.; Ynoue, R.; Rojas, N. Y.; Aristizábal, B. H.; Wahl, M.

    2017-12-01

    Eulerian 3-D chemistry transport models (CTM) have been widely used for the study of air quality in urban environments, becoming an essential tool for studying the impacts and dynamics of gases and aerosols on air quality. However, their use in Colombia is scarce, especially in medium-sized cities, which are experimenting a fast urban growth, increasing the risk associated with possible air pollution episodes. In the densely populated medium-sized Andean city of Manizales, Colombia - a city located on the western slopes of the central range of the Andes (urban population 368000; 2150 m.a.s.l), there is an influence of the active Nevado del Ruiz volcano, located 28 km to the southwest. This natural source emits daily gas and particle fluxes, which could influence the atmospheric chemistry of the city and neighboring towns. Hence, the zone presents a unique combination of anthropogenic and volcanic sulfur gas emissions, which affects SO2 dynamics in the urban area, influencing also in the formation of acid rain phenomenon in the city. Therefore, studies analyzing the relative contribution of anthropogenic and volcanic emission could contribute with a deep understanding about causes and dynamics of both acid rain phenomenon and ambient SO2 levels in Manizales. This work aimed to analyze the influence of anthropogenic (on-road vehicular and industrial point-sources) and volcanic sulfur emissions in SO2 atmospheric chemistry dynamics, evaluating its possible effects on acid rain profiles. Ambient SO2 levels and day-night rain samples were measured and used to analyze results obtained from the application of the fully-coupled on-line WRF-Chem model. Two high-resolution simulations were performed during two dry and wet one-week periods in 2015. Analysis of SO2 dispersion patterns and comparison with SO2 observations in the urban area were performed for three different scenarios in which natural and anthropogenic emissions were simulated separately. Results suggest that

  8. Effects of biomass smoke from southern Africa on stratocumulus over southeastern Atlantic Ocean based on satellite observations and WRF-Chem model simulations

    Science.gov (United States)

    Lu, Z.; Liu, X.; Zhang, Z.; Zhao, C.; Meyer, K.; Rajapakshe, C.; Wu, C.; Yang, Z.; Penner, J.

    2017-12-01

    Each year, large amount of biomass burning (BB) aerosols are emitted over southern Africa, and transported by the predominant circulation to the southeastern Atlantic Ocean (SEA), where they overly and potentially interact with the semi-permanent stratocumulus deck in the marine boundary layer (MBL). Many previous studies suggested that the aerosol plumes are well separated from the MBL clouds, and only focused on the radiative effects of BB aerosols (direct + semi-direct radiative effects); however, as shown in several recent satellite observational studies, BB aerosols are able to be frequently entrained into the underlying clouds, function as cloud condensation nuclei (CCN), and potentially cause microphysical effects. Based on satellite observations from CATS, we found that the mixing frequencies between above-cloud aerosols and MBL clouds are very high ( 50%) over both coastal and remote regions, suggesting that BB aerosols may likely contact MBL cloud top and function as CCN quickly after they are transported over SEA. Despite the potential importance of the microphysical effect of BB aerosols over SEA, its magnitude is not fully assessed by modeling studies. In this study, we employ WRF-Chem model to study the impacts of BB aerosols on MBL stratocumulus clouds over SEA during the fire season of 2014. By designing three cases, we are able to quantitatively determine the relative importance of microphysical and radiative effects of BB aerosols. Our modeling results show that, by serving as CCN, BB aerosols are able to alter cloud properties of stratocumulus (e.g. higher cloud droplet number concentration [CDNC], higher cloud liquid water path [LWP], and larger cloud fraction [CF] before noon) and exert significant cooling effect at TOA (-8.05 Wm-2) over SEA. The cooling is primarily caused by higher CDNC (the Twomey effect), and secondarily by the changes in LWP and CF (the cloud lifetime effect). The semi-direct effect estimated in this study is smaller in

  9. Contribution of ship emissions to the concentration of PM2.5: A comprehensive study using AIS data and WRF/Chem model in Bohai Rim Region, China.

    Science.gov (United States)

    Chen, Dongsheng; Zhao, Na; Lang, Jianlei; Zhou, Ying; Wang, Xiaotong; Li, Yue; Zhao, Yuehua; Guo, Xiurui

    2018-01-01

    Compared with on-road vehicles, emission from ships is one of the least-regulated anthropogenic emission sources and non-negligible source of primary aerosols and gas-phase precursors of PM 2.5 . The Bohai Rim Region in China hosts dozens of large ports, two of which ranked among the top ten ports in the world. To determine the impact of ship emissions on the PM 2.5 concentrations over this region, two parts of works have been conducted in this study. First, a detailed ship emission inventory with high spatiotemporal resolution was developed based on Automatic Identification System (AIS) data. Then the WRF/Chem model was applied to modeling the impact of ship emissions by comparing two scenarios: with and without ship emissions. The results indicate that the total estimated ship emissions of SO 2 , NO X , PM 10 , PM 2.5 , CO, HC, and CO 2 from Bohai Rim Region in 2014 are 1.9×10 5 , 2.9×10 5 , 2.6×10 4 , 2.4×10 4 , 2.5×10 4 , 1.2×10 4 , and 1.3×10 7 tonnes, respectively. The modeling results indicate that the annual PM 2.5 concentrations increased by 5.9% on land areas of Bohai Rim Region (the continent within 115.2°E-124.3°E and 36.1°N-41.6°N) due to ship emissions. The contributions show distinctive seasonal variations of contributions, presenting highest in summer (12.5%) followed by spring (6.9%) and autumn (3.3%), and lowest in winter (0.9%). The contribution reaches up to 10.7% along the shoreline and down to 1.0% 200km inland. After examining the statistics of the modeling results during heavy and non-heavy haze days in July, it was found that 6 out of 9 cities around the Bohai Rim Region were observed with higher contributions from ship emissions during heavy haze days compared with non-heavy haze days. These results indicate that the impacts of ship emissions on the ambient PM 2.5 are non-negligible, especially for heavy haze days for most coastal cities in the Bohai Rim Region. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. WRF-Chem model simulations of a dust outbreak over the central Mediterranean and comparison with multi-sensor desert dust observations

    Science.gov (United States)

    Rizza, Umberto; Barnaba, Francesca; Marcello Miglietta, Mario; Mangia, Cristina; Di Liberto, Luca; Dionisi, Davide; Costabile, Francesca; Grasso, Fabio; Gobbi, Gian Paolo

    2017-01-01

    In this study, the Weather Research and Forecasting model with online coupled chemistry (WRF-Chem) is applied to simulate an intense Saharan dust outbreak event that took place over the Mediterranean in May 2014. Comparison of a simulation using a physics-based desert dust emission scheme with a numerical experiment using a simplified (minimal) emission scheme is included to highlight the advantages of the former. The model was found to reproduce well the synoptic meteorological conditions driving the dust outbreak: an omega-like pressure configuration associated with a cyclogenesis in the Atlantic coasts of Spain. The model performances in reproducing the atmospheric desert dust load were evaluated using a multi-platform observational dataset of aerosol and desert dust properties, including optical properties from satellite and ground-based sun photometers and lidars, plus in situ particulate matter mass concentration (PM) data. This comparison allowed us to investigate the model ability in reproducing both the horizontal and the vertical displacement of the dust plume, as well as its evolution in time. The comparison with satellite (MODIS-Terra) and sun photometers (AERONET) showed that the model is able to reproduce well the horizontal field of the aerosol optical depth (AOD) and its evolution in time (temporal correlation coefficient with AERONET of 0.85). On the vertical scale, the comparison with lidar data at a single site (Rome, Italy) confirms that the desert dust advection occurs in several, superimposed "pulses" as simulated by the model. Cross-analysis of the modeled AOD and desert dust emission fluxes further allowed for the source regions of the observed plumes to be inferred. The vertical displacement of the modeled dust plume was in rather good agreement with the lidar soundings, with correlation coefficients among aerosol extinction profiles up to 1 and mean discrepancy of about 50 %. The model-measurement comparison for PM10 and PM2.5 showed a

  11. Ozone data assimilation with GEOS-Chem: a comparison between 3-D-Var, 4-D-Var, and suboptimal Kalman filter approaches

    Science.gov (United States)

    Singh, K.; Sandu, A.; Bowman, K. W.; Parrington, M.; Jones, D. B. A.; Lee, M.

    2011-08-01

    Chemistry transport models determine the evolving chemical state of the atmosphere by solving the fundamental equations that govern physical and chemical transformations subject to initial conditions of the atmospheric state and surface boundary conditions, e.g., surface emissions. The development of data assimilation techniques synthesize model predictions with measurements in a rigorous mathematical framework that provides observational constraints on these conditions. Two families of data assimilation methods are currently widely used: variational and Kalman filter (KF). The variational approach is based on control theory and formulates data assimilation as a minimization problem of a cost functional that measures the model-observations mismatch. The Kalman filter approach is rooted in statistical estimation theory and provides the analysis covariance together with the best state estimate. Suboptimal Kalman filters employ different approximations of the covariances in order to make the computations feasible with large models. Each family of methods has both merits and drawbacks. This paper compares several data assimilation methods used for global chemical data assimilation. Specifically, we evaluate data assimilation approaches for improving estimates of the summertime global tropospheric ozone distribution in August 2006 based on ozone observations from the NASA Tropospheric Emission Spectrometer and the GEOS-Chem chemistry transport model. The resulting analyses are compared against independent ozonesonde measurements to assess the effectiveness of each assimilation method. All assimilation methods provide notable improvements over the free model simulations, which differ from the ozonesonde measurements by about 20 % (below 200 hPa). Four dimensional variational data assimilation with window lengths between five days and two weeks is the most accurate method, with mean differences between analysis profiles and ozonesonde measurements of 1-5 %. Two sequential

  12. Analysis of CO in the tropical troposphere using Aura satellite data and the GEOS-Chem model: insights into transport characteristics of the GEOS meteorological products

    Directory of Open Access Journals (Sweden)

    Junhua Liu

    2010-12-01

    Full Text Available We use the GEOS-Chem chemistry-transport model (CTM to interpret the spatial and temporal variations of tropical tropospheric CO observed by the Microwave Limb Sounder (MLS and the Tropospheric Emission Spectrometer (TES. In so doing, we diagnose and evaluate transport in the GEOS-4 and GEOS-5 assimilated meteorological fields that drive the model, with a particular focus on vertical mixing at the end of the dry season when convection moves over the source regions. The results indicate that over South America, deep convection in both GEOS-4 and GEOS-5 decays at too low an altitude early in the wet season, and the source of CO from isoprene in the model (MEGAN v2.1 is too large, causing a lag in the model's seasonal maximum of CO compared to MLS CO in the upper troposphere (UT. TES and MLS data reveal problems with excessive transport of CO to the eastern equatorial Pacific and lofting in the ITCZ in August and September, particularly in GEOS-4. Over southern Africa, GEOS-4 and GEOS-5 simulations match the phase of the observed CO variation from the lower troposphere (LT to the UT fairly well, although the magnitude of the seasonal maximum is underestimated considerably due to low emissions in the model. A sensitivity run with increased emissions leads to improved agreement with observed CO in the LT and middle troposphere (MT, but the amplitude of the seasonal variation is too high in the UT in GEOS-4. Difficulty in matching CO in the LT and UT implies there may be overly vigorous vertical mixing in GEOS-4 early in the wet season. Both simulations and observations show a time lag between the peak in fire emissions (July and August and in CO (September and October. We argue that it is caused by the prevailing subsidence in the LT until convection moves south in September, as well as the low sensitivity of TES data in the LT over the African Plateau. The MLS data suggest that too much CO has been transported from fires in northern Africa to the UT

  13. Simulating the meteorology and PM10 concentrations in Arizona dust storms using the Weather Research and Forecasting model with Chemistry (Wrf-Chem).

    Science.gov (United States)

    Hyde, Peter; Mahalov, Alex; Li, Jialun

    2018-03-01

    Nine dust storms in south-central Arizona were simulated with the Weather Research and Forecasting with Chemistry model (WRF-Chem) at 2 km resolution. The windblown dust emission algorithm was the Air Force Weather Agency model. In comparison with ground-based PM 10 observations, the model unevenly reproduces the dust-storm events. The model adequately estimates the location and timing of the events, but it is unable to precisely replicate the magnitude and timing of the elevated hourly concentrations of particles 10 µm and smaller ([PM 10 ]).Furthermore, the model underestimated [PM 10 ] in highly agricultural Pinal County because it underestimated surface wind speeds and because the model's erodible fractions of the land surface data were too coarse to effectively resolve the active and abandoned agricultural lands. In contrast, the model overestimated [PM 10 ] in western Arizona along the Colorado River because it generated daytime sea breezes (from the nearby Gulf of California) for which the surface-layer speeds were too strong. In Phoenix, AZ, the model's performance depended on the event, with both under- and overestimations partly due to incorrect representation of urban features. Sensitivity tests indicate that [PM 10 ] highly relies on meteorological forcing. Increasing the fraction of erodible surfaces in the Pinal County agricultural areas improved the simulation of [PM 10 ] in that region. Both 24-hr and 1-hr measured [PM 10 ] were, for the most part, and especially in Pinal County, extremely elevated, with the former exceeding the health standard by as much as 10-fold and the latter exceeding health-based guidelines by as much as 70-fold. Monsoonal thunderstorms not only produce elevated [PM 10 ], but also cause urban flash floods and disrupt water resource deliveries. Given the severity and frequency of these dust storms, and conceding that the modeling system applied in this work did not produce the desired agreement between simulations and

  14. Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

    Directory of Open Access Journals (Sweden)

    K. Yu

    2018-01-01

    Full Text Available Global simulations of atmospheric chemistry are commonly conducted with off-line chemical transport models (CTMs driven by archived meteorological data from general circulation models (GCMs. The off-line approach has the advantages of simplicity and expediency, but it incurs errors due to temporal averaging in the meteorological archive and the inability to reproduce the GCM transport algorithms exactly. The CTM simulation is also often conducted at coarser grid resolution than the parent GCM. Here we investigate this cascade of CTM errors by using 222Rn–210Pb–7Be chemical tracer simulations off-line in the GEOS-Chem CTM at rectilinear 0.25°  ×  0.3125° (≈ 25 km and 2°  ×  2.5° (≈ 200 km resolutions and online in the parent GEOS-5 GCM at cubed-sphere c360 (≈ 25 km and c48 (≈ 200 km horizontal resolutions. The c360 GEOS-5 GCM meteorological archive, updated every 3 h and remapped to 0.25°  ×  0.3125°, is the standard operational product generated by the NASA Global Modeling and Assimilation Office (GMAO and used as input by GEOS-Chem. We find that the GEOS-Chem 222Rn simulation at native 0.25°  ×  0.3125° resolution is affected by vertical transport errors of up to 20 % relative to the GEOS-5 c360 online simulation, in part due to loss of transient organized vertical motions in the GCM (resolved convection that are temporally averaged out in the 3 h meteorological archive. There is also significant error caused by operational remapping of the meteorological archive from a cubed-sphere to a rectilinear grid. Decreasing the GEOS-Chem resolution from 0.25°  ×  0.3125° to 2°  ×  2.5° induces further weakening of vertical transport as transient vertical motions are averaged out spatially and temporally. The resulting 222Rn concentrations simulated by the coarse-resolution GEOS-Chem are overestimated by up to 40 % in surface air relative to the

  15. Development of a source oriented version of the WRF/Chem model and its application to the California regional PM10 / PM2.5 air quality study

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2014-01-01

    Full Text Available A source-oriented version of the Weather Research and Forecasting model with chemistry (SOWC, hereinafter was developed. SOWC separately tracks primary particles with different hygroscopic properties rather than instantaneously combining them into an internal mixture. This approach avoids artificially mixing light absorbing black + brown carbon particles with materials such as sulfate that would encourage the formation of additional coatings. Source-oriented particles undergo coagulation and gas-particle conversion, but these processes are considered in a dynamic framework that realistically "ages" primary particles over hours and days in the atmosphere. SOWC more realistically predicts radiative feedbacks from anthropogenic aerosols compared to models that make internal mixing or other artificial mixing assumptions. A three-week stagnation episode (15 December 2000 to 6 January 2001 in the San Joaquin Valley (SJV during the California Regional PM10 / PM2.5 Air Quality Study (CRPAQS was chosen for the initial application of the new modeling system. Primary particles emitted from diesel engines, wood smoke, high-sulfur fuel combustion, food cooking, and other anthropogenic sources were tracked separately throughout the simulation as they aged in the atmosphere. Differences were identified between predictions from the source oriented vs. the internally mixed representation of particles with meteorological feedbacks in WRF/Chem for a number of meteorological parameters: aerosol extinction coefficients, downward shortwave flux, planetary boundary layer depth, and primary and secondary particulate matter concentrations. Comparisons with observations show that SOWC predicts particle scattering coefficients more accurately than the internally mixed model. Downward shortwave radiation predicted by SOWC is enhanced by ~1% at ground level chiefly because diesel engine particles in the source-oriented mixture are not artificially coated with material that

  16. Combined impacts of nitrous acid and nitryl chloride on lower-tropospheric ozone: new module development in WRF-Chem and application to China

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2017-08-01

    Full Text Available Nitrous acid (HONO and nitryl chloride (ClNO2 – through their photolysis – can have profound effects on the nitrogen cycle and oxidation capacity of the lower troposphere. Previous numerical studies have separately considered and investigated the sources/processes of these compounds and their roles in the fate of reactive nitrogen and the production of ozone (O3, but their combined impact on the chemistry of the lower part of the troposphere has not been addressed yet. In this study, we updated the WRF-Chem model with the currently known sources and chemistry of HONO and chlorine in a new chemical mechanism (CBMZ_ReNOM, and applied it to a study of the combined effects of HONO and ClNO2 on summertime O3 in the boundary layer over China. We simulated the spatial distributions of HONO, ClNO2, and related compounds at the surface and within the lower troposphere. The results showed that the modeled HONO levels reached up to 800–1800 ppt at the surface (0–30 m over the North China Plain (NCP, the Yangtze River Delta (YRD, and the Pearl River Delta (PRD regions and that HONO was concentrated within a 0–200 m layer. In comparison, the simulated surface ClNO2 mixing ratio was around 800–1500 ppt over the NCP, YRD, and central China regions and was predominantly present in a 0–600 m layer. HONO enhanced daytime ROx (OH + HO2 + RO2 and O3 at the surface (0–30 m by 2.8–4.6 ppt (28–37 % and 2.9–6.2 ppb (6–13 %, respectively, over the three most developed regions, whereas ClNO2 increased surface O3 in the NCP and YRD regions by 2.4–3.3 ppb (or 5–6 % and it also had a significant impact (3–6 % on above-surface O3 within 200–500 m. The combined effects increased surface O3 by 11.5, 13.5, and 13.3 % in the NCP, YRD, and PRD regions, respectively. Over the boundary layer (0–1000 m, the HONO and ClNO2 enhanced O3 by up to 5.1 and 3.2 %, respectively, and their combined effect increased O

  17. Combined impacts of nitrous acid and nitryl chloride on lower-tropospheric ozone: new module development in WRF-Chem and application to China

    Science.gov (United States)

    Zhang, Li; Li, Qinyi; Wang, Tao; Ahmadov, Ravan; Zhang, Qiang; Li, Meng; Lv, Mengyao

    2017-08-01

    Nitrous acid (HONO) and nitryl chloride (ClNO2) - through their photolysis - can have profound effects on the nitrogen cycle and oxidation capacity of the lower troposphere. Previous numerical studies have separately considered and investigated the sources/processes of these compounds and their roles in the fate of reactive nitrogen and the production of ozone (O3), but their combined impact on the chemistry of the lower part of the troposphere has not been addressed yet. In this study, we updated the WRF-Chem model with the currently known sources and chemistry of HONO and chlorine in a new chemical mechanism (CBMZ_ReNOM), and applied it to a study of the combined effects of HONO and ClNO2 on summertime O3 in the boundary layer over China. We simulated the spatial distributions of HONO, ClNO2, and related compounds at the surface and within the lower troposphere. The results showed that the modeled HONO levels reached up to 800-1800 ppt at the surface (0-30 m) over the North China Plain (NCP), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) regions and that HONO was concentrated within a 0-200 m layer. In comparison, the simulated surface ClNO2 mixing ratio was around 800-1500 ppt over the NCP, YRD, and central China regions and was predominantly present in a 0-600 m layer. HONO enhanced daytime ROx (OH + HO2 + RO2) and O3 at the surface (0-30 m) by 2.8-4.6 ppt (28-37 %) and 2.9-6.2 ppb (6-13 %), respectively, over the three most developed regions, whereas ClNO2 increased surface O3 in the NCP and YRD regions by 2.4-3.3 ppb (or 5-6 %) and it also had a significant impact (3-6 %) on above-surface O3 within 200-500 m. The combined effects increased surface O3 by 11.5, 13.5, and 13.3 % in the NCP, YRD, and PRD regions, respectively. Over the boundary layer (0-1000 m), the HONO and ClNO2 enhanced O3 by up to 5.1 and 3.2 %, respectively, and their combined effect increased O3 by 7.1-8.9 % in the three regions. The new module noticeably improved O3

  18. WRF-Chem model predictions of the regional impacts of N2O5 heterogeneous processes on night-time chemistry over north-western Europe

    Directory of Open Access Journals (Sweden)

    D. Lowe

    2015-02-01

    Full Text Available Chemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N2O5 heterogeneous reactive uptake is important regionally in modulating particulate nitrate and has a~modest influence on oxidative chemistry. Results from Weather Research and Forecasting model with Chemistry (WRF-Chem model simulations, run with a detailed volatile organic compound (VOC gas-phase chemistry scheme and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC sectional aerosol scheme, were compared with a series of airborne gas and particulate measurements made over the UK in July 2010. Modelled mixing ratios of key gas-phase species were reasonably accurate (correlations with measurements of 0.7–0.9 for NO2 and O3. However modelled loadings of particulate species were less accurate (correlation with measurements for particulate sulfate and ammonium were between 0.0 and 0.6. Sulfate mass loadings were particularly low (modelled means of 0.5–0.7 μg kg−1air, compared with measurements of 1.0–1.5 μg kg−1air. Two flights from the campaign were used as test cases – one with low relative humidity (RH (60–70%, the other with high RH (80–90%. N2O5 heterogeneous chemistry was found to not be important in the low-RH test case; but in the high-RH test case it had a strong effect and significantly improved the agreement between modelled and measured NO3 and N2O5. When the model failed to capture atmospheric RH correctly, the modelled NO3 and N2O5 mixing ratios for these flights differed significantly from the measurements. This demonstrates that, for regional modelling which involves heterogeneous processes, it is essential to capture the ambient temperature and water vapour profiles. The night-time NO3 oxidation of VOCs across the whole region was found to be 100–300 times slower than the daytime OH oxidation of these compounds. The difference in contribution was less

  19. Part I: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin Part II: The development of ChemSort: an education game for organic chemistry

    Science.gov (United States)

    Granger, Jenna Christine

    Part 1: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin. Asymmetric organocatalysis, the catalysis of asymmetric reactions by small organic molecules, is a rapidly growing field within organic synthesis. The ability to rationally design organocatalysts is therefore of increasing interest to organic chemists. Computational chemistry is quickly proving to be an extremely successful method for understanding and predicting the roles of organocatalysts, and therefore is certain to be of use in the rational design of such catalysts. A methodology for reverse-docking flexible organocatalysts to rigid transition state models of asymmetric reactions has been previously developed by the Deslongchamps group. The investigation of Rawal's squaramide-based organocatalyst for the addition of a diketone to a nitro-olefin is described, and the results of the reverse docking of Rawal's catalyst to the geometry optimized transition state models of the uncatalyzed reaction for both the R and S-product enantiomers are presented. The results of this study indicate a preference for binding of the organocatalyst to the R-enantiomer transition state model with a predicted enantiomeric excess of 99%, which is consistent with the experimental results. A plausible geometric model of the transition state for the catalyzed reaction is also presented. The success of this study demonstrates the credibility of using reverse docking methods for the rational design of asymmetric organocatalysts. Part 2: The development of ChemSort: an educational game for organic chemistry. With the advent of the millennial learner, we need to rethink traditional classroom approaches to science learning in terms of goals, approaches, and assessments. Digital simulations and games hold much promise in support of this educational shift. Although the idea of using games for education is not a new one, well-designed computer-based "serious games" are only beginning to

  20. Spatio-temporal variability of CO and O3 in Hyderabad (17°N, 78°E, central India, based on MOZAIC and TES observations and WRF-Chem and MOZART-4 models

    Directory of Open Access Journals (Sweden)

    Varun Sheel

    2016-05-01

    Full Text Available This article is based on the study of the seasonal and interannual variability of carbon monoxide (CO and ozone (O3 at different altitudes of the troposphere over Hyderabad, India, during 2006–2010 using Measurement of OZone and water vapour by Airbus In-Service Aircraft (MOZAIC and observation from Tropospheric Emission Spectrometer (TES aboard NASA's Aura satellite. The MOZAIC observations show maximum seasonal variability in both CO and O3 during winter and pre-monsoon season, with CO in the range (100–200±13 ppbv and O3 in the range (50–70±9 ppbv. The time-series of MOZAIC data shows a significant increase of 4.2±1.3 % in the surface CO and 6.7±1.3 % in the surface O3 during 2006–2010 in Hyderabad. From MOZAIC observations, we identify CO and O3 profiles that are anomalous with respect to the monthly mean and compare those with Weather Research Forecast model coupled with Chemistry (WRF-Chem and Model for OZone and Related Tracers, version 4 profiles for the same day. The anomalous profiles of WRF-Chem are simulated using three convection schemes. The goodness of comparison depends on the convection scheme and the altitude region of the troposphere.

  1. Application of WRF/Chem over the Continental U.S. under the AQMEII Phase II: Part 2. Evaluation of 2010 Application and Responses of Air Quality and Meteorology-Chemistry Interactions to Changes in Emissions and Meteorology from 2006 to 2010

    Science.gov (United States)

    The Weather Research and Forecasting model with Chemistry (WRF/Chem) simulation with the 2005 Carbon Bond (CB05) gas-phase mechanism coupled to the Modal for Aerosol Dynamics for Europe (MADE) and the Volatility Basis Set (VBS) approach for secondary organic aerosol (SOA) (MADE/V...

  2. Comparison of Predicted pKa Values for Some Amino-Acids, Dipeptides and Tripeptides, Using COSMO-RS, ChemAxon and ACD/Labs Methods Comparaison des valeurs de pKa de quelques acides aminés, dipeptides et tripeptides, prédites en utilisant les méthodes COSMO-RS, ChemAxon et ACD/Labs

    Directory of Open Access Journals (Sweden)

    Toure O.

    2013-05-01

    Full Text Available Liquid-phase pKa values play a key role in food science. Chemical properties of molecules depend largely on whether they are ionized or not. Most organic molecules are capable of gaining and/or losing a proton in aqueous solutions. Proton transfer most. frequently occurs between water and any ionizable atom of the organic molecule. The molecule’s response to profanation or deprotonation depends significantly on the site that was disturbed by proton transfer. Partial charge distribution in the molecule also varies with protonation of the acidlbase active sites. Then it can he used to determine the pKa of a molecule. First, we use the COSMO-RS method, a combination of the quantum chemical dielectric continuum solvation model COSMO with a statistical thermodynamics treatment fin- more Realistic Solvation (RS simulations, for the direct prediction of pKa constants of about 50 molecules (amino-acids, dipeptides and tripeptides. Then, we compare our results with experimental data and the pKa values predicted using two other methods. We used respectively the ChemAxon method using a program based on the calculation of partial charge of atoms in the molecule and the ACD/Labs method that enables to calculate single pKa values. for all possible dissociation centers when the rest of the molecule is considered neutral, using an internal database containing chemical structures and their experimental pKa values. The averaged Root Mean Square Error (RMSE of the predicted pKa values for each method compared to experimental results were respectively 0.596 for COSMO-RS, 0.445 for ChemAxon and 0.490 for ACD/Labs. While ACDILabs and ChemAxon are parameterized using a large set ofexperimental data (including several of the studied molecules, the COSMO- RS method was used in a fully predictive way. Regarding these results, COSMO-RS appears as a promising method to predict the pKa values of molecules of interest in food science with scarce available pKa values such

  3. Rad Chem data acquisition chassis users manual

    International Nuclear Information System (INIS)

    Jones, B.A.

    1980-01-01

    The Shiva Laser at LLL requires many forms of diagnostics to measure and analyze fusion experiments. This manual describes the operation of a Micro-Processor controlled data acquisition system designed at LLL to measure Neutron Activation during fusion experiments on the Shiva Laser

  4. ChemWaste appeals Hanford permit stance

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Chemical Waste Management, Inc. is appealing the Washington State Department of Ecology's decision to suspend its review of the company's proposal to build a hazardous waste incinerator and two mixed waste incinerators at the Hanford Nuclear Site near Richland, Washington. The company wants to build the incinerators on a 200 acre parcel in the DOE reservation that is leased to the State. The State contends the two mixed waste incinerators meet siting criteria, but the hazardous waste unit does not. A compromise may be reached between DOE and Washington state involving the transfer of title to the leased land from DOE to the State

  5. ChemSearch Journal: Editorial Policies

    African Journals Online (AJOL)

    A. A. Audu (Analytical Chemistry) Department of Pure and Industrial Chemistry, Bayero University, P.M.B. 3011, Kano, Nigeria. Prof. S. M. Gumel (Colour & Polymer Chemistry) Department of Pure and Industrial Chemistry, Bayero University, P.M.B. 3011, Kano, Nigeria. Prof. S. Y. Mudi (Organic Chemistry) Department of ...

  6. Performance of WRF-Chem over Indian region: Comparison with ...

    Indian Academy of Sciences (India)

    1. Introduction. Aerosols affect the Earth's radiation budget by ... to increase in cloud droplet (for fixed cloud liquid ... vulnerable to the adverse impact of climate change. Composite aerosol ... India using two chemistry transport models, namely ...

  7. Bull. Chem. Soc. Ethiop. 1996, 10(2)

    African Journals Online (AJOL)

    fingerprint indices are recommended. INTRODUCTION. The ever-increasing discharges .... The gas chromatographic profiles of all the samples are identical, so it may be assumed that these oils are from the same source materials, formed under different geological conditions. The isoprenoid and n-paraffinic composition of ...

  8. Blending Chem-Bio Dispersion Forecasts and Sensor Data

    Science.gov (United States)

    2008-12-31

    Kerrie Long. 5d. PROJECT NUMBER N/A 5e. TASK NUMBER N/A 5f. WORK UNIT NUMBER N/A 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) CUBRC ...Acknowlegments I gratefully acknowledge the efforts of the team of faculty, consultants and graduate students from CUBRC , the University at Buffalo, the...Moskal, CUBRC Alex James, CUBRC 3.5 Graduate Students Umamaheswara Reddy, Dept. Mechanical Engineering, University at Buffalo Gabriel Terejanu

  9. Chem I Supplement: Liquid Crystals--The Chameleon Chemicals.

    Science.gov (United States)

    Brown, Glenn H.

    1983-01-01

    Presents information relevant to everyday life so as to stimulate student interest in the properties of the two basic types of liquid crystals: thermotropic and lyotropic. Describes the applications of liquid crystals to electronics, biomedicine, and polymer science and appraises the future of liquid crystal research. (JM)

  10. ChemSearch Journal - Vol 7, No 2 (2016)

    African Journals Online (AJOL)

    Quantitative analysis of caffeine in some selected brands of energy drinks available in Kano State Nigeria · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. M.I. Mohammed, J Abdulrauf, A.S. Bayero, 24-27 ...

  11. 2007 Joint Chem Bio Decon and Protection Conference and Exhibition

    Science.gov (United States)

    2007-10-25

    Choung USMC Ms. Lindy Burkhart USN Mr. Carl Goalie Technical Manager (Navy) Mr. Kiko Lama Transition Manager (Joint) LTC Green Oversight Group DUSD (AS&C...may not be possible to pull units for decon for days at a time UNCLASSIFIED UNCLASSIFIED 13 Mud, Crud, & Blood • Should be assumed as a

  12. Bull.Chem.Soc.Ethiop.,4(1)

    African Journals Online (AJOL)

    axial coordination of halides stabilizes the copper(III) state of copper macrocyclic complexes. ... employed and tetraethylammonium perchlorate, or reagent grade acids were used as supporting electrolytes. RESULTS AND .... Summary of kinetic parameters for acid dependent Fe(phen)3+ oxidetions of b-diimine complexes.

  13. Zhao et al. (2017) Chem. Geol. v. 474 p.1

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset provides information on chromium concentrations extracted from rock samples collected at the Garfield SF site in New Jersey (USA). The data are discussed...

  14. Plasmonic Paper as a Novel Chem/Bio Detection Platform

    Science.gov (United States)

    Tian, Limei

    The time varying electric field of electromagnetic (EM) radiation causes oscillation of conduction electrons of metal nanoparticles. The resonance of such oscillation, termed localized surface plasmon resonance (LSPR), falls into the visible spectral region for noble metals such as gold, silver and copper. LSPR of metal nanostructures is sensitive to numerous factors such as composition, size, shape, dielectric properties of surrounding medium, and proximity to other nanostructures (plasmon coupling). The sensitivity of LSPR to the refractive index of surrounding medium renders it an attractive platform for chemical and biological sensing. When the excitation light is in resonance with the plasmon frequency of the metal nanoparticle, it radiates a characteristic dipolar radiation causing a characteristic spatial distribution in which certain areas show higher EM field intensity, which is manifested as electromagnetic field enhancement. Surface enhanced Raman scattering (SERS) involves dramatic enhancement of the intensity of the Raman scattering from the analyte adsorbed on or in proximity to a nanostructured metal surface exhibiting such strong EM field enhancement. Both LSPR and SERS have been widely investigated for highly sensitive and label-free chemical & biological sensors. Most of the SERS/LSPR sensors demonstrated so far rely on rigid planar substrates (e.g., glass, silicon) owing to the well-established lithographic approaches, which are routinely employed for either fabrication or assembly of plasmonic nanotransducers. In many cases, their rigid nature results in low conformal contact with the sample and hence poor sample collection efficiency. We hypothesized that paper substrates are an excellent alternative to conventional rigid substrates to significantly improve the (multi-)functionality of LSPR/SERS substrates, dramatically simplify the fabrication procedures and lower the cost. The choice of paper substrates for the implementation of SERS/LSPR sensors is rationalized by numerous advantages such as (i) high specific surface area resulting in large dynamic range (ii) excellent wicking properties for rapid uptake and transport of analytes to test domains (iii) compatibility with conventional printing approaches, enabling multi-analyte plasmonic sensors (iv) significant reduction in cost (v) smaller sample volume requirement (vi) easy disposability. In this work, we have introduced novel SERS and LSPR substrates based on conventional filter paper decorated with plasmonic nanostructures, called plasmonic paper. A flexible SERS substrate based on common filter paper adsorbed with gold nanostructures allows conformal contact with real-world surfaces, enabling rapid trace detection. To realize multifunctional SERS substrates, paper substrates were cut into star-shaped structures and the fingers were differentially functionalized with polyelectrolytes that allows separation and pre-concentration of different components of a complex sample in a small surface area by taking advantage of the properties of cellulose paper and shape-enhanced capillary effect. Plasmonic paper can also serve as a novel LSPR biosensing platform by decorating the paper substrate with biofunctionalized nanostructures. Furthermore, calligraphy approach was employed to create well-isolated test domains on paper substrates using functionalized plasmonic nanostructures as ink for multiplexed chemical sensing and label-free biosensing. These plasmonic paper substrates exhibit excellent sample collection efficiency and do not require complex fabrication processes. This class of substrates is expected to have applications not only to first responders and military personal but also to several areas of medical, food analysis, and environmental research.

  15. Wide Range Digitizer for Chem-Bio LIDAR

    National Research Council Canada - National Science Library

    Green, Norman; Moon, Raphael

    2004-01-01

    .... Typically, receiver amplifier gain is adjusted from time-to-time so that signal amplitude applied to the digitizer is not too large, resulting in a signal clipping, nor too small, resulting in poor digitizer resolution...

  16. ChemSearch Journal - Vol 5, No 2 (2014)

    African Journals Online (AJOL)

    Bipyridinium Tetrachloronickelate (II) and 4,4′-Bipyridine Dichloronickel (II) Complexes · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. MA Kurawa, SG Yammama, 59-65 ...

  17. I:\\AA-TYPESET\\CHEM\\2006\\Van Es.vp

    African Journals Online (AJOL)

    NJD

    aDepartment of Biochemistry and Microbiology, Cook College, Rutgers, The State University of New Jersey, 08903-0231, USA. bSchool of Chemistry, University of the Witwatersrand, Johannesburg, South Africa. cVisiting Associate, Department of Chemistry and Biomolecular Sciences, Macquarie University, NSW 2109, ...

  18. Report on Concepts & Approaches for SSBD for eCHEM

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Chantell Lynne-Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-29

    The verification of special nuclear material (SNM) in spent fuel pyroprocessing is an important safeguards challenge. The detection of spontaneous fission (SF) neutrons from curium is an accepted, non-destructive technique that has been applied to verify special nuclear material (SNM) content in used fuel and other materials in the fuel cycle. The nuclear material accounting (NMA) technique at the Korea Atomic Energy Research Institute’s Reference Engineering-scale Pyroprocessing Facility (REPF) is based on the Cm balance technique. Several publications have demonstrated the safeguards benefit from using process monitoring (PM) on nuclear facilities as a complementary measure to NMA. More recently, this concept was expanded and preliminarily demonstrated for pyroprocessing. The concept of Signature Based Safeguards (SBS) is part of this expansion, and is built around the interpretation of input from various sensors in a declared facility coupled with complementary NMA methods to increase confidence and lower standard error inventory differences (SEID). The SBS methodology was conceptually developed and relies on near real time analysis of process monitoring data to detect material diversion complemented by robust containment and surveillance (C/S) measures. This work demonstrates one example of how the SBS framework can be used in the electrorefiner. In this SBS application, a combination of cyclic voltammetry (CV) and neutron counting is applied to track and monitor Pu mass balance. The main purpose of this experiment is to determine if meaningful information can be gained from CV measurements with regard to the Mg/Gd ratio. This data will be coupled with ICP-MS to verify Gd concentrations and analyzed for statistical significance. It is expected the CV data will register a significant change under the off-normal operating conditions. Knowing how to identify and interpret those changes may help inform how to target more traditional neutron counting methods, which could support a more efficient safeguards system. The experimental results will be compared with theoretical calculations and the ERAD simulations.

  19. Mixed Solvent + Electrolyte

    Indian Academy of Sciences (India)

    Prof.Biswas

    Bagchi B and Biswas R. 1999 Adv. Chem. Phys.109 207. 2. Kashyap H K and Biswas R. 2008 J. Phys. Chem. B112 12431. 3. Kashyap H K and Biswas R. 2010J. Phys. Chem. B114, 254. 4. Kashyap H K and Biswas R. 2010 J. Phys. Chem. B114, 16811. 5. Kashyap H K and Biswas R. 2010 Ind. J. Chem. 49A, 685. 6.

  20. Zinc nanoparticles in solution by laser ablation technique

    Indian Academy of Sciences (India)

    TECS

    Fujiwara H, Yanagida S and Kamat P V 1999 J. Phys. Chem. B103 2589. Geohegan D B, Puretzky A A, Duscher G and Pennycook S J. 1998 Appl. Phys. Lett. 72 2987. Henglein A, Gutierrez M, Janata E and Ershov B G 1992 J. Phys. Chem. 96 4598. Hodak J H, Henglein A, Giersig M and Hartland G V 2000 J. Phys. Chem.

  1. Retraction notice to: Artificial intelligence in pharmaceutical product formulation: Neural computing [Chem. Ind. Chem. Eng. Q. 15(4) (2009) 227-236

    OpenAIRE

    Ibrić Svetlana; Đurić Zorica; Parojčić Jelena; Petrović Jelena

    2011-01-01

    This article has been retracted at the request of the authors. The retraction has been made because the authors admitted that they took the text and rawings from the review article written by R. Rowe and E. Colbourn, Future Medicinal Chemistry 1(4) (2009) 713-726, without their permission and even did not include this article in the list of references. One of the conditions of submission of a paper for publication are that authors confirm that their work is entirely originally written, someon...

  2. Retraction: Graphene-SnO2 nanocomposites decorated with quantum tunneling junctions: preparation strategies, microstructures and formation mechanism.

    Science.gov (United States)

    Simpson, Anna

    2017-09-20

    Retraction of 'Graphene-SnO 2 nanocomposites decorated with quantum tunneling junctions: preparation strategies, microstructures and formation mechanism' by Qingxiu Wang et al., Phys. Chem. Chem. Phys., 2014, 16, 19351-19357.

  3. Correction: Conceptual design of tetraazaporphyrin- and subtetraazaporphyrin-based functional nanocarbon materials: electronic structures, topologies, optical properties, and methane storage capacities.

    Science.gov (United States)

    Belosludov, Rodion V; Rhoda, Hannah M; Zhdanov, Ravil K; Belosludov, Vladimir R; Kawazoe, Yoshiyuki; Nemykin, Victor N

    2017-08-02

    Correction for 'Conceptual design of tetraazaporphyrin- and subtetraazaporphyrin-based functional nanocarbon materials: electronic structures, topologies, optical properties, and methane storage capacities' by Rodion V. Belosludov et al., Phys. Chem. Chem. Phys., 2016, 18, 13503-13518.

  4. Correction: The effect of recombination under short-circuit conditions on the determination of charge transport properties in nanostructured photoelectrodes.

    Science.gov (United States)

    Villanueva-Cab, J; Anta, J A; Oskam, G

    2016-05-28

    Correction for 'The effect of recombination under short-circuit conditions on the determination of charge transport properties in nanostructured photoelectrodes' by J. Villanueva-Cab et al., Phys. Chem. Chem. Phys., 2016, 18, 2303-2308.

  5. Ultraviolet Photoionization Efficiency of the Vaporized Ionic Liquid 1-Butyl-3-Methylimidazolium Tricyanomethanide: Direct Detection of the Intact Ion Pair (Post Print)

    Science.gov (United States)

    2012-09-21

    Lovelock , K. R. J.; Satterly, C. J.; Villar-Garcia, I. J. Phys. Chem. Chem. Phys. 2007, 9, 982−990. (11) Strasser, D.; Goulay, F.; Kelkar, M. S.; Maginn, E...J.; Leone, S. R. J. Phys. Chem. A 2007, 111, 3191−3915. (12) Lovelock , K. R. J.; Deyko, A.; Corfield, J.-A.; Gooden, P. N.; Licence, P.; Jones, R. G

  6. Remote detection of chem/bio hazards via coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    2017-09-12

    hour per response, including the time for reviewing lnstnJctions, searching existing data sources, gathering and maintaining the data needed, and... time remote detection of hazardous microparticles in atmosphere and to evaluate the range of distances for typical species and the parameters of laser...detectable photons from a prototype molecule at a distance. 1S. SUBJECT TERMS Stimulated Raman scattering, Remote detection, biochemical agents, explosives

  7. Chem mical c a compo uxiliar sition ry treat of med tments dicina s ...

    African Journals Online (AJOL)

    SAM

    samples were further processed by lyophilization of the plant mucilage (A. vera) ... 100 and the sum (in dry matter) of the ether extract, protein, ash and total dietary fiber. ..... meability of cell membranes (Francis et al., 2002); this information highlights the ... plasma by forming micelles in the small intestine with bile acids, thus ...

  8. Chem-Bio Self-Decontaminating Surfaces (Briefing Slides). AFRL Quarterly Summary on DARPA Effort

    National Research Council Canada - National Science Library

    Wander, Joseph D; Heimbuch, Brian K; O'Gurek, Kimberly R

    2007-01-01

    ...% coefficient of variation). Successful delivery (CV = 7.2%) of Staphylococcus aureus at 10e4/sq cm was also achieved in the small-scale chamber by aerosolization in a medium containing 1% raffinose...

  9. Chapter-10.ppt | Chemistry-352 | harvey | www.chem.wwu.edu ...

    Indian Academy of Sciences (India)

    error. The page your are looking for can not be found! Please check the link or use the navigation bar at the top. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 January 2018. The 29th Mid-year meeting of the Academy will be held from 29–30 June 2018 in Infosys, Mysuru ...

  10. I:\\AA-TYPESET\\CHEM\\2005\\van der Westhuyzen.vp

    African Journals Online (AJOL)

    NJD

    used drugs has made it imperative that new methods of combat- ing this scourge be .... A new product, 5, was obtained as a single isomer in. 20–30% yield. ... undertaken on the two alkene hydrogen atoms individually to determine their ...

  11. ChemCam-like Spectrometer for Non-Contact Measurements of Key Isotopes, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal addresses NASA SBIR topic S1.07 In Situ Sensors for Lunar and Planetary Science, particularly the need for measuring isotopic ratios of the key...

  12. ChemCam-like Spectrometer for Non-Contact Measurements of Key Isotopes, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses the need for a non-contact instrument capable of measuring the isotopic ratios O-18/O-16 and D/H from water ice and other solid materials...

  13. Wilkin and Beak (2017) ChemGeol v462 p15

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset includes X-ray Diffraction, Raman spectroscopic, X-ray absorption spectroscopic, and aqueous data pertaining to the paper titled "Uptake of nickel by...

  14. ChemSession'06 - 3rd Seminary of Warsaw PhD Students in Chemistry. Abstracts

    International Nuclear Information System (INIS)

    Zachara, J.; Lulinski, S.; Dobrowolski, J.C.; Raczynska, E.D.; Fuks, L.; Cyranski, M.K.; Stepien, B.T.; Sawicki, M.G.

    2006-01-01

    3 rd Annual Seminary of Warsaw PhD Students in Chemistry presented the latest achievements in chemistry, obtained in all Warsaw universities and scientific institutes. In 2006 participants presented 4 plenary lectures, and 109 posters. Among others, posters covered four disciplines related to the nuclear sciences: (a) radiobiology and radiotherapy, (b) radiation chemistry and photochemistry, (c) isotopic effects in chemistry, and (d) chemical technology

  15. Chem I Supplement. Chemistry Related to Isolation of High-Level Nuclear Waste.

    Science.gov (United States)

    Hoffman, Darleane C.; Choppin, Gregory R.

    1986-01-01

    Discusses some of the problems associated with the safe disposal of high-level nuclear wastes. Describes several waste disposal plans developed by various nations. Outlines the multiple-barrier concept of isolation in deep geological questions associated with the implementation of such a method. (TW)

  16. Chem I Supplement: Bee Sting: The Chemistry of an Insect Venom.

    Science.gov (United States)

    O'Connor, Rod; Peck, Larry

    1980-01-01

    Considers various aspects of bee stings including the physical mechanism of the venom apparatus in the bee, categorization of physiological responses of nonprotected individuals to bee sting, chemical composition of bee venom and the mechanisms of venom action, and areas of interest in the synthesis of bee venom. (CS)

  17. 17th Radiochemical conference: RadChem 2014 Marianske Lazne, 11-16th May 2014

    Czech Academy of Sciences Publication Activity Database

    John, J.; Kučera, Jan; Vobecký, Miloslav; Mizera, Jiří; Špendlíková, I.

    2015-01-01

    Roč. 304, č. 1 (2015), s. 1-6 ISSN 0236-5731 Institutional support: RVO:68081715 ; RVO:61389005 Keywords : DNC FNSPE CTU * NRC * DNRC EuCheMS * IUPAC Subject RIV: CH - Nuclear ; Quantum Chemistry; CB - Analytical Chemistry, Separation (UIACH-O) Impact factor: 0.983, year: 2015

  18. From small to powerful: the fragments universe and its "chem-appeal".

    Science.gov (United States)

    Sancineto, Luca; Massari, Serena; Iraci, Nunzio; Tabarrini, Oriana

    2013-01-01

    While increasing expertise in molecular biology and proteomics is markedly speeding up the target elucidation process, various strategies have been proposed that improve the chances of identifying active molecules. Among them, the Fragment Based Drug Design (FBDD) is surely worth noting. The FBDD entails the screening of a small number of low molecular weight compounds in the hopes of finding even low affine but high ligand efficient fragments that have high probability to became drug candidates. Since 1996, when the first paper on FBDD was reported, the potentialities of this strategy became progressively more apparent as testified by the growing number of publications. Many drug discovery projects started with the identification of fragments which after the optimization gave many molecules close to the approval and one marketed drug Vemurafenib, approved in 2011. A preamble that highlights the advantages of dealing with simple and "very small" molecules over conventional drug-like compounds will be herein given prior to discussing the canonical FBDD stages, from fragment library design, to the different screening methods concluding with the various optimization strategies, in an attempt to illustrate the whole FBDD workflow while discussing the most recent and successful applications. While this review is a tribute to the success achieved by the researchers in this field, it is particularly addressed to scientists who want to become aware of the versatility and potentiality of FBDD.

  19. I:\\AA-TYPESET\\CHEM\\2009\\Janse van Rensburg.vp

    African Journals Online (AJOL)

    NJD

    cyclic transition state in a concerted fashion (Scheme 3), which is consistent with .... where ∆Grot is the Gibbs energy of rotation, R is the gas constant,. T is the ... solutions using a Bruker (Karlsruhe, Germany) Avance 400 MHz spectrometer.

  20. Computational Model of Secondary Palate Fusion and Disruption ChemResTox Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Morphogenetic events are driven by cell-generated physical forces and complex cellular dynamics. To improve our capacity to predict developmental effects from...

  1. ChemDuino: Adapting Arduino for Low-Cost Chemical Measurements in Lecture and Laboratory

    Science.gov (United States)

    Kubínova´, S?te?pa´nka; S?le´gr, Jan

    2015-01-01

    In everyday praxis, we often need demonstration measuring devices (thermometers, pH meters, etc.), with large enough displays to be easily readable from every point in the classroom. Here, we present some of the capabilities of the Arduino platform for the school environment. This microprocessor board can be used for inexpensive construction of…

  2. First Principles Modeling of the Performance of a Hydrogen-Peroxide-Driven Chem-E-Car

    Science.gov (United States)

    Farhadi, Maryam; Azadi, Pooya; Zarinpanjeh, Nima

    2009-01-01

    In this study, performance of a hydrogen-peroxide-driven car has been simulated using basic conservation laws and a few numbers of auxiliary equations. A numerical method was implemented to solve sets of highly non-linear ordinary differential equations. Transient pressure and the corresponding traveled distance for three different car weights are…

  3. ChemSession'07 - 4th Seminary of Warsaw PhD Students in Chemistry. Abstracts

    International Nuclear Information System (INIS)

    Dobrowolski, J.C.; Ostrowski, S.; Madura, I.; Sporzynski, A.; Szatylowicz, H.; Zubrowska, A.

    2007-01-01

    4 th Annual Seminary of Warsaw PhD Students in Chemistry presented the latest achievements in chemistry, obtained in all Warsaw universities and scientific institutes. In 2007 participants presented 4 plenary lectures, and 101 posters. Among others, posters covered four disciplines related to the nuclear sciences: (a) radiobiology and radiotherapy, (b) radiation chemistry and photochemistry, (c) isotopic effects in chemistry, and (d) chemical technology

  4. Global sensitivity analysis of GEOS-Chem modeled ozone and hydrogen oxides during the INTEX campaigns

    Directory of Open Access Journals (Sweden)

    K. E. Christian

    2018-02-01

    Full Text Available Making sense of modeled atmospheric composition requires not only comparison to in situ measurements but also knowing and quantifying the sensitivity of the model to its input factors. Using a global sensitivity method involving the simultaneous perturbation of many chemical transport model input factors, we find the model uncertainty for ozone (O3, hydroxyl radical (OH, and hydroperoxyl radical (HO2 mixing ratios, and apportion this uncertainty to specific model inputs for the DC-8 flight tracks corresponding to the NASA Intercontinental Chemical Transport Experiment (INTEX campaigns of 2004 and 2006. In general, when uncertainties in modeled and measured quantities are accounted for, we find agreement between modeled and measured oxidant mixing ratios with the exception of ozone during the Houston flights of the INTEX-B campaign and HO2 for the flights over the northernmost Pacific Ocean during INTEX-B. For ozone and OH, modeled mixing ratios were most sensitive to a bevy of emissions, notably lightning NOx, various surface NOx sources, and isoprene. HO2 mixing ratios were most sensitive to CO and isoprene emissions as well as the aerosol uptake of HO2. With ozone and OH being generally overpredicted by the model, we find better agreement between modeled and measured vertical profiles when reducing NOx emissions from surface as well as lightning sources.

  5. Demonstration of Linked UAV Observations and Atmospheric Model Predictions in Chem/Bio Attack Response

    National Research Council Canada - National Science Library

    Davidson, Kenneth

    2003-01-01

    ... meteorological data, and the means for linking the UAV data to real-time dispersion prediction. The primary modeling effort focused on an adaptation of the 'Wind On Constant Streamline Surfaces...

  6. KinChem: A Computational Resource for Teaching and Learning Chemical Kinetics

    Science.gov (United States)

    da Silva, Jose´ Nunes, Jr.; Sousa Lima, Mary Anne; Silva Sousa, Eduardo Henrique; Oliveira Alexandre, Francisco Serra; Melo Leite, Antonio Jose´, Jr.

    2014-01-01

    This paper presents a piece of educational software covering a comprehensive number of topics of chemical kinetics, which is available free of charge in Portuguese and English. The software was developed to support chemistry educators and students in the teaching-learning process of chemical kinetics by using animations, calculations, and…

  7. Aqueous Processing of Si3N4 Powder with Chem-Adsorbed Silanes

    National Research Council Canada - National Science Library

    Colic, Miroslav

    1996-01-01

    .... Addition of salt to dispersed silicon nitride slurries with particles coated with polyethyleneglycol-silane, caused the collapse of the 22 atoms long chains and residual electrical double layer...

  8. Utilizing A One-Atmosphere Uniform Discharge Plasma for Bio/Chem Agent Sterilization/Decon

    National Research Council Canada - National Science Library

    McLean, M

    1998-01-01

    .... This was demonstrated using the simulant methyl salicylate (oil of wintergreen). Gas chromatography/mass spectrometry results indicate the formation of a new species with a molecular weight 16 amu greater than methyl salicylate...

  9. Highlights from e-EPS: EPS and EuChems are joining forces

    CERN Multimedia

    2013-01-01

    e-EPS News is an addition to the CERN Bulletin line-up, showcasing articles from e-EPS – the European Physical Society newsletter – as part of a collaboration between the two publications.   On the occasion of the EPS Council 2013 in Strasbourg, a memorandum of understanding was signed between the European Association for Chemical and Molecular Societies (EuCheMS) and the European Physical Society (EPS) by presidents Ulrich Schubert and Luisa Cifarelli. EuCheMS and EPS share many objectives, such as community building, scientific excellence, communication and representation of their respective members to European policy makers. The two societies recognise that issues in many fields such as education, publication, support for basic sciences and frontier research are similar in their respective disciplines. They wish to combine efforts in developing and presenting common standpoints to their mutual benefit as European representatives in chemistry ...

  10. Heats of Vaporization of Room Temperature Ionic Liquids by Tunable Vacuum Ultraviolet Photoionization

    Science.gov (United States)

    2009-12-07

    18) Emel’yanenko, V. N.; Verevkin, S. P.; Heintz, A.; Corfield, J.-A.; deyko, A.; Lovelock , K. R. J.; Licence, P.; Jones, R. G. J. Phys. Chem. B 2008...112, 11734. (19) Armstrong, J. P.; Hurst, C.; Jones, R. G.; Licence, P.; Lovelock , K. R. J.; Satterly, C. J.; Villar-Garcia, I. J. Phys. Chem. Chem...Phys. 2007, 9, 982. (20) Lovelock , K. R. J.; Deyko, A.; Corfield, J.-A.; Gooden, P. N.; Licence, P.; Jones, R. G. ChemPhysChem 2009, 10, 337. (21

  11. Fluorine effect on pericyclic and pseudopericyclic processes ...

    Indian Academy of Sciences (India)

    Administrator

    Glendening E D, Reed A E, Carpenter J E and Wein- hold F 1988 NBO 3.1 Program Manual. 39. Fukui K 1981 Acc. Chem. Res. 14 363. 40. Gonzalez C and Schlegel H B 1989 J. Chem. Phys. 90 2154. 41. Gonzalez C and Schlegel H B 1990 J. Phys. Chem. 94 5223. 42. Wolinski K, Hilton J F and Pulay P 1990 J. Am. Chem.

  12. PhysLink Physics and Astronomy online education and reference

    CERN Document Server

    The PhysLink.com is a comprehensive physics and astronomy online education, research and reference web site. In addition to providing high-quality content, PhysLink.com is a meeting place for professionals, students and other curious minds.

  13. A quantum - classical simulation of a multi-surface multi-mode ...

    Indian Academy of Sciences (India)

    Chem. Phys. 10 6388. [12] Sardar S, Paul A K, Sharma R and Adhikari S 2009 J. Chem. Phys. 130 144302. [13] Sardar S, Paul A K, and Adhikari S 2009 Mol. Phys. 23-24 2467. [14] Sardar S, Paul A K, Sharma R, Adhikari S, 2011 Int. J. Quant. Chem. 111 2741. [15] Dirac P A M, 1930 Proc. Cambridge Philos. Soc. 26 376. 5.

  14. Cover Feature: LEGO-Inspired Drug Design: Unveiling a Class of Benzo[d]thiazoles Containing a 3,4-Dihydroxyphenyl Moiety as Plasma Membrane H+-ATPase Inhibitors (ChemMedChem 1/2018)

    DEFF Research Database (Denmark)

    Thanh Tung, Truong; Dao, Trong Tuan; Grifell Junyent, Marta

    2018-01-01

    The Cover Feature shows a rational procedure for assembling privileged molecular fragments (like playing with LEGO bricks) to obtain hit structures. We have invented a novel procedure for targeting biological macromolecules possessing a binding site with a poorly known topography. We have coined ......, 2018 (DOI: 10.1002/cmdc.201700635)....

  15. Exploring Physics with Computer Animation and PhysGL

    Science.gov (United States)

    Bensky, T. J.

    2016-10-01

    This book shows how the web-based PhysGL programming environment (http://physgl.org) can be used to teach and learn elementary mechanics (physics) using simple coding exercises. The book's theme is that the lessons encountered in such a course can be used to generate physics-based animations, providing students with compelling and self-made visuals to aid their learning. Topics presented are parallel to those found in a traditional physics text, making for straightforward integration into a typical lecture-based physics course. Users will appreciate the ease at which compelling OpenGL-based graphics and animations can be produced using PhysGL, as well as its clean, simple language constructs. The author argues that coding should be a standard part of lower-division STEM courses, and provides many anecdotal experiences and observations, that include observed benefits of the coding work.

  16. Chemical Compound Navigator: A Web-Based Chem-BLAST, Chemical Taxonomy-Based Search Engine for Browsing Compounds

    Czech Academy of Sciences Publication Activity Database

    Prasanna, M. D.; Vondrášek, Jiří; Wlodawer, A.; Rodriguez, H.; Bhat, T. N.

    2006-01-01

    Roč. 63, č. 4 (2006), s. 907-917 ISSN 0887-3585 Institutional research plan: CEZ:AV0Z40550506 Keywords : HIV * AIDS * drug discovery * chemical data-tree Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.730, year: 2006

  17. Chemical variations in Yellowknife Bay formation sedimentary rocks analyzed by ChemCam on board the Curiosity rover on Mars

    Science.gov (United States)

    Mangold, Nicolas; Forni, Olivier; Dromart, G.; Stack, K.M.; Wiens, Roger C.; Gasnault, Olivier; Sumner, Dawn Y.; Nachon, Marion; Meslin, Pierre-Yves; Anderson, Ryan B.; Barraclough, Bruce; Bell, J.F.; Berger, G.; Blaney, D.L.; Bridges, J.C.; Calef, F.; Clark, Brian R.; Clegg, Samuel M.; Cousin, Agnes; Edgar, L.; Edgett, Kenneth S.; Ehlmann, B.L.; Fabre, Cecile; Fisk, M.; Grotzinger, John P.; Gupta, S.C.; Herkenhoff, Kenneth E.; Hurowitz, J.A.; Johnson, J. R.; Kah, Linda C.; Lanza, Nina L.; Lasue, Jeremie; Le Mouélic, S.; Lewin, Eric; Malin, Michael; McLennan, Scott M.; Maurice, S.; Melikechi, Noureddine; Mezzacappa, Alissa; Milliken, Ralph E.; Newsome, H.L.; Ollila, A.; Rowland, Scott K.; Sautter, Violaine; Schmidt, M.E.; Schroder, S.; D'Uston, C.; Vaniman, Dave; Williams, R.A.

    2015-01-01

    The Yellowknife Bay formation represents a ~5 m thick stratigraphic section of lithified fluvial and lacustrine sediments analyzed by the Curiosity rover in Gale crater, Mars. Previous works have mainly focused on the mudstones that were drilled by the rover at two locations. The present study focuses on the sedimentary rocks stratigraphically above the mudstones by studying their chemical variations in parallel with rock textures. Results show that differences in composition correlate with textures and both manifest subtle but significant variations through the stratigraphic column. Though the chemistry of the sediments does not vary much in the lower part of the stratigraphy, the variations in alkali elements indicate variations in the source material and/or physical sorting, as shown by the identification of alkali feldspars. The sandstones contain similar relative proportions of hydrogen to the mudstones below, suggesting the presence of hydrous minerals that may have contributed to their cementation. Slight variations in magnesium correlate with changes in textures suggesting that diagenesis through cementation and dissolution modified the initial rock composition and texture simultaneously. The upper part of the stratigraphy (~1 m thick) displays rocks with different compositions suggesting a strong change in the depositional system. The presence of float rocks with similar compositions found along the rover traverse suggests that some of these outcrops extend further away in the nearby hummocky plains.

  18. ChemSession'07 - 4{sup th} Seminary of Warsaw PhD Students in Chemistry. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Dobrowolski, J C [Industrial Chemistry Research Institute, Warsaw (Poland); National Institute of Drugs, Warsaw (Poland); Ostrowski, S [Industrial Chemistry Research Institute, Warsaw (Poland); Madura, I; Sporzynski, A; Szatylowicz, H; Zubrowska, A [Warsaw University of Technology, Warsaw (Poland)

    2007-07-01

    4{sup th} Annual Seminary of Warsaw PhD Students in Chemistry presented the latest achievements in chemistry, obtained in all Warsaw universities and scientific institutes. In 2007 participants presented 4 plenary lectures, and 101 posters. Among others, posters covered four disciplines related to the nuclear sciences: (a) radiobiology and radiotherapy, (b) radiation chemistry and photochemistry, (c) isotopic effects in chemistry, and (d) chemical technology.

  19. Sensor-enabled chem/bio contamination detection system dedicated to situational awareness of water distribution security status

    Science.gov (United States)

    Ginsberg, Mark D.; Smith, Eddy D.; VanBlaricum, Vicki; Hock, Vincent F.; Kroll, Dan; Russell, Kevin J.

    2010-04-01

    Both real events and models have proven that drinking water systems are vulnerable to deliberate and/or accidental contamination. Additionally, homeland security initiatives and modeling efforts have determined that it is relatively easy to orchestrate the contamination of potable water supplies. Such contamination can be accomplished with classic and non-traditional chemical agents, toxic industrial chemicals (TICs), and/or toxic industrial materials (TIMs). Subsequent research and testing has developed a proven network for detection and response to these threats. The method uses offthe- shelf, broad-spectrum analytical instruments coupled with advanced interpretive algorithms. The system detects and characterizes any backflow events involving toxic contaminants by employing unique chemical signature (fingerprint) response data. This instrumentation has been certified by the Office of Homeland Security for detecting deliberate and/or accidental contamination of critical water infrastructure. The system involves integration of several mature technologies (sensors, SCADA, dynamic models, and the HACH HST Guardian Blue instrumentation) into a complete, real-time, management system that also can be used to address other water distribution concerns, such as corrosion. This paper summarizes the reasons and results for installing such a distribution-based detection and protection system.

  20. ConfChem Conference on Flipped Classroom: Just-in-Time Teaching in Chemistry Courses with Moodle

    Science.gov (United States)

    Muzyka, Jennifer L.

    2015-01-01

    In the Just-in-Time Teaching approach, a faculty member assigns readings to students before every class. After the students have done the daily reading, they access a short reading quiz using a course management system (e.g., Moodle). The faculty member uses student responses to the quiz in the preparation of the day's class material and is able…

  1. ACToR Chemical Structure processing using Open Source ChemInformatics Libraries (FutureToxII)

    Science.gov (United States)

    ACToR (Aggregated Computational Toxicology Resource) is a centralized database repository developed by the National Center for Computational Toxicology (NCCT) at the U.S. Environmental Protection Agency (EPA). Free and open source tools were used to compile toxicity data from ove...

  2. Handheld Chem/Biosensor Using Extreme Conformational Changes in Designed Binding Proteins to Enhance Surface Plasmon Resonance (SPR)

    Science.gov (United States)

    2016-04-01

    characteristics similar to a random coil conformation. By increasing the solution ionic strength it is possible to screen the side chain charges and... characteristics of metallic thin films perforated with subwavelength-sized apertures, spawned the research field of metamaterials and anomalous transmission...Veldhoven, Netherlands). Following a post-exposure bake on a hotplate at 95 °C for 90 s, each wafer was developed in AZ®726 MIF (MicroChemicals GmbH

  3. Autoclave Operator (chem.) 4-52.711--Technical Report on Standardization of the General Aptitude Test Battery.

    Science.gov (United States)

    Manpower Administration (DOL), Washington, DC. U.S. Training and Employment Service.

    The United States Training and Employment Service General Aptitude Test Battery (GATB), first published in 1947, has been included in a continuing program of research to validate the tests against success in many different occupations. The GATB consists of 12 tests which measure nine aptitudes: General Learning Ability; Verbal Aptitude; Numerical…

  4. 2005 Science and Technology for Chem-Bio Information Systems (S and T CBIS). Volume 2 - Wednesday

    Science.gov (United States)

    2005-10-28

    Integration (6.3) 5 Guidelines for ’06 Projects • Develop cells within digital dashboard • Java • Minimal GUI development, use digital dashboard to maximum...JTF Medical Planners JTF Medical Logistics CBRN-Medical COI Pilot Project NBC Control Center NBC Cell NBC Decon Team CBRN Detect NBC Ops/Plans...Institut für Umwelttechnologien GmbH CAR INSPECTION BY NT1 Institut für Umwelttechnologien GmbH Identification of booby traps by NT1 Institut für

  5. WasteChem Corporation's Volume Reduction and Solidification (VRS) system for low-level radwaste treatment: Final report

    International Nuclear Information System (INIS)

    1988-01-01

    Since 1965, low and medium level radwastes from nuclear power stations, reprocessing plants and nuclear research centers have been stabilized using the Volume Reduction and Solidification (VRS) system. The VRS system uses an extruder/evaporator to evaporate the liquids from waste influents, while simultaneously incorporating the remaining radioactive solids in an asphalt binder. In the period 1965 to 1986 a minimum of 700,000 cubic feet of wastes have been processed with the VRS system. This report provides current operating data from various systems including the volume reduction factors achieved, and the progress of start-ups in the US. The report also provides previously unpublished experience with mixed wastes including uranium raffinate and nitrate-bearing sludges from surface impoundments. VRS systems in the US are currently operating at the Palisades and Hope Creek nuclear stations. These systems produce a variety of waste types including boric acid, bead resin, sodium sulfate and powdered resins. There are three start-ups of VRS systems scheduled in the US in 1987. These systems are at Fermi 2, Seabrook, and Nine Mile Point 2. Overseas, the startup of new systems continues with three VRS process lines coming on-line at the LaHague Reprocessing Center in France in 1986 and a start-up scheduled for 1987 at the Laguna Verde plant in Mexico. The US systems are operating continuously and with little required maintenance. Data on maintenance and the operator exposure are provided in this report. 6 refs., 11 figs., 13 tabs

  6. ChemSession'06 - 3{sup rd} Seminary of Warsaw PhD Students in Chemistry. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, J; Lulinski, S [Warsaw University of Technology, Warsaw (Poland); Dobrowolski, J C [Industrial Chemistry Research Institute, Warsaw (Poland); National Institute of Drugs, Warsaw (Poland); Raczynska, E D [Warsaw University of Life Sciences (SGGW), Warsaw (Poland); Fuks, L [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Cyranski, M K; Stepien, B T [University of Warsaw, Warsaw (Poland); Sawicki, M G [Cecylia Plater-Zylberkowna High School, Warsaw (Poland)

    2006-07-01

    3{sup rd} Annual Seminary of Warsaw PhD Students in Chemistry presented the latest achievements in chemistry, obtained in all Warsaw universities and scientific institutes. In 2006 participants presented 4 plenary lectures, and 109 posters. Among others, posters covered four disciplines related to the nuclear sciences: (a) radiobiology and radiotherapy, (b) radiation chemistry and photochemistry, (c) isotopic effects in chemistry, and (d) chemical technology.

  7. IM-Chem: The Use of Instant Messaging to Improve Student Performance and Personalize Large Lecture General Chemistry Courses

    Science.gov (United States)

    Behmke, Derek A.; Atwood, Charles H.

    2012-01-01

    Previous research has linked poor student performance with the depersonalized feeling of large lecture courses. Various forms of enhanced communication have been tried that appear to enhance personalization in large courses. For general chemistry classes taught in a 365-seat lecture hall at the University of Georgia, we have attempted to enhance…

  8. First Directly Retrieved Global Distribution of Tropospheric Column Ozone from GOME: Comparison with the GEOS-CHEM Model

    Science.gov (United States)

    Liu, Xiong; Chance, Kelly; Sioris, Christopher E.; Kurosu, Thomas P.; Spurr, Robert J. D.; Martin, Randall V.; Fu, Tzung-May; Logan, Jennifer A.; Jacob, Daniel J.; Palmer, Paul I.; hide

    2006-01-01

    We present the first directly retrieved global distribution of tropospheric column ozone from Global Ozone Monitoring Experiment (GOME) ultraviolet measurements during December 1996 to November 1997. The retrievals clearly show signals due to convection, biomass burning, stratospheric influence, pollution, and transport. They are capable of capturing the spatiotemporal evolution of tropospheric column ozone in response to regional or short time-scale events such as the 1997-1998 El Nino event and a 10-20 DU change within a few days. The global distribution of tropospheric column ozone displays the well-known wave-1 pattern in the tropics, nearly zonal bands of enhanced tropospheric column ozone of 36-48 DU at 20degS-30degS during the austral spring and at 25degN-45degN during the boreal spring and summer, low tropospheric column ozone of 33 DU at some northern high-latitudes during the spring. Simulation from a chemical transport model corroborates most of the above structures, with small biases of <+/-5 DU and consistent seasonal cycles in most regions, especially in the southern hemisphere. However, significant positive biases of 5-20 DU occur in some northern tropical and subtropical regions such as the Middle East during summer. Comparison of GOME with monthly-averaged Measurement of Ozone and Water Vapor by Airbus in-service Aircraft (MOZAIC) tropospheric column ozone for these regions usually shows good consistency within 1 a standard deviations and retrieval uncertainties. Some biases can be accounted for by inadequate sensitivity to lower tropospheric ozone, the different spatiotemporal sampling and the spatiotemporal variations in tropospheric column ozone.

  9. Proton-proton elastic scattering at the LHC energy of \\chem{\\sqrt{s} = 7\\,TeV}

    Science.gov (United States)

    TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgö, T.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Perrot, A.-L.; Palazzi, P.; Pedreschi, E.; Petäjäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vitek, M.; Welti, J.; Whitmore, J.

    2011-08-01

    Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at \\sqrt{s} = 7\\,TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of \\delta t = 0.1\\,\\rm{GeV} \\sqrt{\\vert t\\vert } . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6 ± 0.5stat ± 0.4syst) GeV-2, followed by a significant diffractive minimum at |t| = (0.53 ± 0.01stat ± 0.01syst) GeV2. For |t|-values larger than ~1.5 GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8 ± 0.3stat ± 0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.

  10. Megacity impacts on regional ozone formation: observations and WRF-Chem modeling for the MIRAGE-Shanghai field campaign

    Directory of Open Access Journals (Sweden)

    X. Tie

    2013-06-01

    Full Text Available The MIRAGE-Shanghai experiment was designed to characterize the factors controlling regional air pollution near a Chinese megacity (Shanghai and was conducted during September 2009. This paper provides information on the measurements conducted for this study. In order to have some deep analysis of the measurements, a regional chemical/dynamical model (version 3 of Weather Research and Forecasting Chemical model – WRF-Chemv3 is applied for this study. The model results are intensively compared with the measurements to evaluate the model capability for calculating air pollutants in the Shanghai region, especially the chemical species related to ozone formation. The results show that the model is able to calculate the general distributions (the level and the variability of air pollutants in the Shanghai region, and the differences between the model calculation and the measurement are mostly smaller than 30%, except the calculations of HONO (nitrous acid at PD (Pudong and CO (carbon monoxide at DT (Dongtan. The main scientific focus is the study of ozone chemical formation not only in the urban area, but also on a regional scale of the surrounding area of Shanghai. The results show that during the experiment period, the ozone photochemical formation was strongly under the VOC (volatile organic compound-limited condition in the urban area of Shanghai. Moreover, the VOC-limited condition occurred not only in the city, but also in the larger regional area. There was a continuous enhancement of ozone concentrations in the downwind of the megacity of Shanghai, resulting in a significant enhancement of ozone concentrations in a very large regional area in the surrounding region of Shanghai. The sensitivity study of the model suggests that there is a threshold value for switching from VOC-limited condition to NOx (nitric oxide and nitrogen dioxide-limited condition. The threshold value is strongly dependent on the emission ratio of NOx / VOCs. When the ratio is about 0.4, the Shanghai region is under a strong VOC-limited condition over the regional scale. In contrast, when the ratio is reduced to about 0.1, the Shanghai region is under a strong NOx-limited condition. The estimated threshold value (on the regional scale for switching from VOC-limited to NOx-limited condition ranges from 0.1 to 0.2. This result has important implications for ozone production in this region and will facilitate the development of effective O3 control strategies in the Shanghai region.

  11. "ChemMend": A Card Game to Introduce and Explore the Periodic Table While Engaging Students' Interest

    Science.gov (United States)

    Martí-Centelles, Vicente; Rubio-Magnieto, Jenifer

    2014-01-01

    Deep knowledge of the periodic table is one of the most important keys to understand the basic principles of Chemistry. Memorizing the elements of the groups and periods is one of the most commonly used strategies to learn the position of each element in the periodic table; nevertheless, it is a hard task for most students. The use of card games…

  12. XRD and UV-Vis diffuse reflectance analysis of CeO2–ZrO2 solid ...

    Indian Academy of Sciences (India)

    Unknown

    Bera P, Patil K C, Jayaram V, Subbanna G N and Hegde M S 2000 J. Catal. 196 293. 11. Busca G 1999 Phys. Chem. Chem. Phys. 1 723. 12. Sugunan S and Varghese B 1998 Indian J. Chem. A37 806. 13. Yamaguchi T 1994 Catal. Today 20 199. 14. Aramendia M A, Borau V, Jimenez C, Marinas J M, Porras A and Urbano ...

  13. Correction: Electronic structure of the boron fullerene B14 and its silicon derivatives B13Si+, B13Si- and B12Si2: a rationalization using a cylinder model.

    Science.gov (United States)

    Van Duong, Long; Nguyen, Minh Tho

    2016-08-28

    Correction for 'Electronic structure of the boron fullerene B 14 and its silicon derivatives B 13 Si + , B 13 Si - and B 12 Si 2 : a rationalization using a cylinder model' by Long Van Duong et al., Phys. Chem. Chem. Phys., 2016, 18, 17619-17626.

  14. Correction: Towards the rationalization of catalytic activity values by means of local hyper-softness on the catalytic site: a criticism about the use of net electric charges.

    Science.gov (United States)

    Martínez-Araya, Jorge Ignacio; Grand, André; Glossman-Mitnik, Daniel

    2016-01-28

    Correction for 'Towards the rationalization of catalytic activity values by means of local hyper-softness on the catalytic site: a criticism about the use of net electric charges' by Jorge Ignacio Martínez-Araya et al., Phys. Chem. Chem. Phys., 2015, DOI: 10.1039/c5cp03822g.

  15. How Much Weaker Are the Effects of Cations than Those of Anions?

    DEFF Research Database (Denmark)

    Morita, Takeshi; Westh, Peter; Nishikawa, Keilo

    2014-01-01

    We characterized the effects of K+ and Cs+ ions on the molecular organization of H2O by the 1-propanol probing methodology, previously developed by us (Phys. Chem. Chem. Phys. 2013, 15, 14548). The results indicated that both ions belong to the class of “hydration center”, which is hydrated by 4...

  16. Correction: General optimization procedure towards the design of a new family of minimal parameter spin-component-scaled double-hybrid density functional theory.

    Science.gov (United States)

    Roch, Loïc M; Baldridge, Kim K

    2018-02-07

    Correction for 'General optimization procedure towards the design of a new family of minimal parameter spin-component-scaled double-hybrid density functional theory' by Loïc M. Roch and Kim K. Baldridge, Phys. Chem. Chem. Phys., 2017, 19, 26191-26200.

  17. Synthesis, crystal structure, thermal analysis and dielectric ...

    Indian Academy of Sciences (India)

    [13] Perry C H and Lowdes R P 1969 J. Chem. Phys. 51 3648. [14] Sheldrick G M 1997 SHELXS9, Program for the Refinement of Crystal Structures (Germany: University of Gottingen). [15] Loukil M, Kabadou A, Salles Ph and Ben Salah A 2004 Chem. Phys. 300 247. [16] Rolies M M and De Ranter C J 1978 Acta Crystallogr.

  18. Fluorescence anisotropy of acridinedione dyes in glycerol: Prolate ...

    Indian Academy of Sciences (India)

    TECS

    61 5083. 26. Srividya N, Ramamurthy P and Ramakrishnan V T. 1998 Spectrochim. Acta 54 245. 27. Venkatachalapathy B and Ramamurthy P 1999 Phys. Chem. Chem. Phys. 1 2223. 28. Indirapriyadharshini V K, Karunanithi P and Rama- murthy P 2001 Langmuir 17 4056. 29. Thiagarajan V, Selvaraju C, Padmamalar E J ...

  19. Thermal Decomposition Mechanisms of Alkylimidazolium Ionic Liquids with CN-containing Anions

    Science.gov (United States)

    2014-11-01

    S. P., Heintz, A., Corfield, J.-A., Deyko, A., Lovelock , K. R. J., Licence, P. and Jones, R. G. Journal of Physical Chemistry B, 2008, 112, 11734...Jones, R. G., Licence, P., Lovelock , K. R. J., Satterly, C. J. and Villar-Garcia, I. J. Phys. Chem. Chem. Phys., 2007, 9, 982-990. (45) Holloczki

  20. On the equivalence of LIST and DIIS methods for convergence acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Garza, Alejandro J. [Department of Chemistry, Rice University, Houston, Texas 77251-1892 (United States); Scuseria, Gustavo E. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892, USA and Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-04-28

    Self-consistent field extrapolation methods play a pivotal role in quantum chemistry and electronic structure theory. We, here, demonstrate the mathematical equivalence between the recently proposed family of LIST methods [Wang et al., J. Chem. Phys. 134, 241103 (2011); Y. K. Chen and Y. A. Wang, J. Chem. Theory Comput. 7, 3045 (2011)] and the general form of Pulay’s DIIS [Chem. Phys. Lett. 73, 393 (1980); J. Comput. Chem. 3, 556 (1982)] with specific error vectors. Our results also explain the differences in performance among the various LIST methods.

  1. Supersonic Jet Studies of Benzyl Alcohols: Minimum Energy Conformations and Torsional Motion

    Science.gov (United States)

    1990-05-13

    New York: 1980. (46) Bernstein, E. R.; Law, K.; Schauer, M. J. Chem. Phys. 1984, 80, 207. (47) Hanzlik , R. P.; Schaefer , A. R.; Moon , J. B.; Judson , C...M. J. Am. Chem. Soc. 1987 , 109 , 4926 . -32- Table I. Conformations of substituted benzenes as established by laser jet spectroscopy. jY x 1 ortho T...Chem. Soc. 1987 , 109 , 3453. -29- (11) Breen, P. J.; Bernstein, E. R.; Seeman, J. I. J. Chem, Phys. 1987 , 87, 3269. (12) Breen, P. J.; Warren, J. A

  2. Preface: phys. stat. sol. (a) 202/12

    Science.gov (United States)

    Neumann, Wolfgang; Stutzmann, Martin; Hildebrandt, Stefan

    2005-09-01

    The present special issue contains a collection of Original Papers dedicated to Professor Johannes Heydenreich on the occasion of his 75th birthday.Johannes Heydenreich, born on 20 June 1930 in Plauen/Vogtland near Dresden, studied physics at the Pädagogische Hochschule Potsdam, where he obtained his first academic degree Dipl. Phys. in 1958. He received his doctoral degree at the Martin Luther University in Halle in 1961 and the Habilitation degree in 1969. Already during his studies in Potsdam, he showed an interest in electron microscopy due to the influence of his teacher and supervisor Prof. Picht, one of the pioneers in electron optics. His interests were strengthened when Johannes Heydenreich did the experimental work for his Diploma degree at the Institute for Experimental Physics of the University of Halle, where he met Prof. Heinz Bethge for the first time. This was the beginning of a fruitful and longstanding collaboration. In 1962 Johannes Heydenreich joined the team of the later Institute for Solid State Physics and Electron Microscopy of the Academy of Sciences of the GDR, in Halle, for which the basis was laid by Prof. Bethge in 1960.Heydenreich has been working as Assistant Director for many years and played a decisive role in introducing and organising the various techniques of electron microscopy in the institute.The research activities of Prof. Heydenreich covered a broad spectrum over the years. At the beginning of his career he made significant contributions in the field of electron mirror microscopy. After that, his main interests were focused on transmission electron microscopy, ranging from diffraction contrast analysis of crystal defects to high-resolution electron microscopy and image processing. His favourite field was studies of defect-induced phenomena in advanced materials. The so-called Bethge-Heydenreich, the book Electron Microscopy in Solid State Physics, published at first in a German edition in 1982 and later in a revised

  3. Microstructure analysis of chemically synthesized wurtzite-type CdS ...

    Indian Academy of Sciences (India)

    37, 4682 (1998). [12] O Z Angel and R L Morales, Phys. Rev. B 62, 13064 (2000). [13] S Wei and S B Zhang, Phys. Rev. B 62, 6944 (2000). [14] G Lin, J Zheng and R Xu, J. Phy. Chem. C 112, 7363 (2008). [15] N Bao, L Shen, T Takata, K Domen, A Gupta, K Yanagisawa and C A Grimes, J. Phys. Chem. C 111, 17527 (2007).

  4. Analysis of Cl…Cl and C–H…Cl intermolecular interactions ...

    Indian Academy of Sciences (India)

    Administrator

    Rae A D and Desiraju G R 1993 J. Chem. Soc. Perkin. Trans. 2 2353. 7. Choudhury A R and Row T N G 2004 Cryst. Growth. Des. 4 47; Thalladi V R, Weiss H-C, Blдser D, Boese. R, Nangia A and Desiraju G R 1998 J. Am. Chem. Soc. 120 8702. 8. Chopra D, Cameron T S, Ferrara J D and Row T N G. 2006 J. Phys. Chem.

  5. Structure and intermolecular vibrations of 7-azaindole-water 2:1 ...

    Indian Academy of Sciences (India)

    Crespo-Hernández C E, Cohen B, Hare P M and Kohler. B 2004 Chem. Rev. 104 1977. 37. Löwdin P D 1966 Adv. Quant. Chem. 2 213. 38. Folmer D E, Poth L, Wisniewski E S and Castleman Jr. A W 1998 Chem. Phys. Lett. 287 1. 39. Folmer D E, Wisniewski E S, Hurley S M and Castleman. Jr A W 1999 Proc. Natl. Acad.

  6. Efimov effect in 2-neutron halo nuclei

    Indian Academy of Sciences (India)

    . B33, 563 (1970). [3] V Efimov, Comm. Nucl. Part. Phys. 19, 271 (1990). [4] Th Cornelius and W Glöckle, J. Chem. Phys. 85, 3906 (1986). B D Esry, C D Lin and C H Greene, Phys. Rev. A54, 394 (1996). J P D'Incao, H Suno and B D Esry, Phys.

  7. Dynamics of Electronically Excited Species in Gaseous and Condensed Phase

    Science.gov (United States)

    1989-12-01

    evaluate the Jacobian J v we make use of the numerical algorithm developed by Stodden and Micha 16, extending it to the equations of motion in...field of the average potential V(Q). The set of equations, Eq. (57), has been recently derived by Stodden and Micha 17 by evaluating directly the...Swaminathan, C. D. Stodden , and D. A. Micha, J. Chem. Phys 99 5501 (1989). 6 R. A. Marcus, Chem. Phys. Lett. 7, 525 (1970); J. Chem. Phys. 54, 3935 (1971); 56

  8. The dependence of lipid monolayer lipolysis on surface pressure.

    OpenAIRE

    Hall, D G

    1992-01-01

    Brönsted-Bjerrum theory [Brönsted (1922) Z. Phys. Chem. 102, 169-207; (1925) Z. Phys. Chem. 115, 337-364; Bjerrum (1924) Z. Phys. Chem. 108, 82-100] as applied to reactions at interfaces is used to interpret published data on the lipolysis of dinonanoyl phosphatidylcholine monolayers by pancreatic phospholipase A2. Reasonable quantitative agreement between theoretical and experimental results occurs when the reported effects of surface pressure on the amount of adsorbed enzyme are used togeth...

  9. Shape, size and temperature dependency of thermal expansion ...

    Indian Academy of Sciences (India)

    M GOYAL

    2018-05-19

    May 19, 2018 ... Oriental J. Chem.32(4), 2193 (2016), is extended in the present study using Qi and Wang model [Mater. Chem. Phys. ... Nanomaterials; shape factor; size effect; thermal expansion; equation of state. ... als are different from that of their bulk material. ..... and 1c along with the present calculated results. It is.

  10. Self-assembly of azobenzene based side-chain liquid crystalline ...

    Indian Academy of Sciences (India)

    . Grimsdale A C and Müllen K 2005 Angew. Chem. Int. Ed. 44 5592. 20. Serpe M J and Craig S L 2007 Langmuir 23 1626. 21. Delphia Shalini Rosalyn P, Senthil S, Kannan P, Vinitha. G and Ramalingam A 2007 J. Phys. Chem. Solids 68. 1812.

  11. Cage Compounds as Potential Energetic Oxidizers: A Theoretical Study of a Cage Isomer of N2O3

    Science.gov (United States)

    2014-07-01

    Laboratory. References [1] P. W. M. Jacobs, H. M. Whitehead, Decomposition and Combustion of Ammonium Perchlorate, Chem. Rev., 1969, 69 551- 590 . [2...and Symmetric Dinitrogen Trioxide in Nitric-Oxide Matrices by Raman and Infrared- Spectroscopy, J. Phys. Chem. 1983, 87, 1113- 1120. [14] a) X. Wang

  12. Untitled

    Indian Academy of Sciences (India)

    Gouterman M. 1978 in The porphyrins (ed.) D Dolphin (New York: Academic Press) vol.3, pp. 157–231. Gouterman M, Schwarz F P, Smith PD and Dolphin D 1973 J. Chem. Phys. 59 676. Merkel P. P and Kearns D R 1972 J. Am. Chem. Soc. 94 7241. Norris Jr J R and Meiser D (eds) 1989 Photochemical emergy conversion ...

  13. Molecular Engineering of Liquid Crystalline Polymers

    Science.gov (United States)

    1992-03-27

    Szasz , N. Sheppard and D. H. Rank, J. Chem. Phys., 1948, 16..704 119. P. B. Woller and E. W. Garbisch, Jr., J. Am. Chem. Soc., 1972, 94, 53 10 120. A. L...schematic representation of a sanidic (from Greek for boardlike) mesophase.202 Figure 15. a) Layer spacing d calculated according to Bragg’s law

  14. Studies on electron transfer reactions: Reduction of heteropoly 10 ...

    Indian Academy of Sciences (India)

    Administrator

    , Amat E, Genestar C and Palou J 1987 J. Radioanalytical and Nuclear Chem. 116 459. 9. Martin J F and Spence J T 1970 J. Phys. Chem. 74. 3589. 10. Ayoko G A and Olatunji M A 1983 Polyhedron 2. 577. 11. Sun J and Stanbury D M 2002 J.

  15. Comment on 'Nonlinear gyrokinetic theory with polarization drift' [Phys. Plasmas 17, 082304 (2010)

    International Nuclear Information System (INIS)

    Leerink, S.; Parra, F. I.; Heikkinen, J. A.

    2010-01-01

    In this comment, we show that by using the discrete particle distribution function the changes of the phase-space volume of gyrocenter coordinates due to the fluctuating ExB velocity do not explicitly appear in the Poisson equation and the [Sosenko et al., Phys. Scr. 64, 264 (2001)] result is recovered. It is demonstrated that there is no contradiction between the work presented by Sosenko et al. and the work presented by [Wang et al., Phys. Plasmas 17, 082304 (2010)].

  16. ADDENDUM: nutraceuticals for protection and healing of gastrointestinal mucosa. Romano M, Vitaglione P, Sellitto S, D'Argenio G. Curr Med Chem 2012, 19: 109-117.

    Science.gov (United States)

    Romano, Marco

    2014-01-01

    This invited review on the beneficial effects of nutraceuticals in the gastrointestinal tract reports previous work conducted by the authors as well as the work by other researchers in this expanding field. The text of our article on several occasions reports sentences very similar or identical to those which appear in the manuscript from which the information was obtained and this applies to both our own work and some other researchers' work. This was mainly due to the fact that we tried to maintain unchanged the original meaning of what we reported in our review. Also, it was our intention to give full credit to the authors of manuscripts dealing with the gastrointestinal effects of nutraceuticals and in some instances we preferred to quote the original paper rather than the review where this original information was taken from. We realize that a number (8) of manuscripts, source of the information reported in our review, were not included in the reference list (which contains over 100 references) and we deeply apologize for this with the authors of the missing references. In most of the cases this was due to a mistake in the final editing of the manuscript. In some other cases this was because we tried not to exceed the number of references requested. We therefore, by means of this addendum, would like to add to the reference list taken out the articles which were not quoted in the manuscript at the time it was published. Two of the articles deal with the effect of nutraceuticals in the upper gastrointestinal tract. The remaining six deal with the effect of nutraceuticals in the lower gastrointestinal tract.

  17. MERRA Chem 3D IAU Edge Pressure, Instantaneous 3-Hourly (eta coord, 2/3x1/2L73) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAI3NECHM or inst3_3d_chm_Ne data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layer Edges that is time averaged, 3D model...

  18. MERRA Chem 3D IAU, Precip Mass Flux, Time average 3-hourly (eta coord edges, 1.25X1L73) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3FECHM or tavg3_3d_chm_Fe data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layers edges that is time averaged, 3D model...

  19. Selective pH-Responsive Core-Sheath Nanofiber Membranes for Chem/Bio/Med Applications: Targeted Delivery of Functional Molecules.

    Science.gov (United States)

    Han, Daewoo; Steckl, Andrew J

    2017-12-13

    Core-sheath fibers using different Eudragit materials were successfully produced, and their controlled multi-pH responses have been demonstrated. Core-sheath fibers made of Eudragit L 100 (EL100) core and Eudragit S 100 (ES100) sheath provide protection and/or controlled release of core material at pH 6 by adjusting the sheath thickness (controlled by the flow rate of source polymer solution). The thickest sheath (∼250 nm) provides the least core release ∼1.25%/h, while the thinnest sheath (∼140 nm) provides much quicker release ∼16.75%/h. Furthermore, switching core and sheath material dramatically altered the pH response. Core-sheath fibers made of ES100 core and EL100 sheath can provide a consistent core release rate, while the sheath release rate becomes higher as the sheath layer becomes thinner. For example, the thinnest sheath (∼120 nm) provides a core and sheath release ratio of 1:2.5, while the thickest sheath (∼200 nm) shows only a ratio of 1:1.7. All core-sheath Eudragit fibers show no noticeable release at pH 5, while they are completely dissolved at pH 7. Extremely high surface area in the porous network of the fiber membranes provides much faster (>30 times) response to external pH changes as compared to that of equivalent cast films.

  20. QSAR pre-screen of 70,983 substances for genotoxic carcinogenicity, mutagenicity and developmental toxicity in the EU FP7 project ChemScreen

    DEFF Research Database (Denmark)

    Wedebye, Eva Bay; Dybdahl, Marianne; Nikolov, Nikolai Georgiev

    2014-01-01

    be performed in REACH on known genotoxic carcinogens or germ cell mutagens with appropriate risk management measures implemented, a QSAR pre-screen for genotoxic carcinogenicity, germ cell mutagenicity and (limited) developmental toxicity was included in the project. Predictions for estrogenic and anti...... algorithms were applied to combine the predictions from the individual models to reach overall predictions for genotoxic carcinogenicity, germ cell mutagenicity and developmental toxicity. Furthermore, the full list of REACH pre-registered substances (143,835) was searched for substances containing certain...

  1. MERRA Chem 2D IAU Diagnostics, Fluxes and Meteorology, Diurnal (surface, 1.25x1L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUFXCHM or tavgU_3d_chm_Fx data product is the MERRA Data Assimilation System Chemistry 2-Dimensional chemistry that is time averaged, single-level, at reduced...

  2. MERRA Chem 2D IAU Diagnostics, Fluxes and Meteorology, Time Average 3-hourly (surface, 1.25x1L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3FXCHM or tavg3_3d_chm_Fx data product is the MERRA Data Assimilation System Chemistry 2-Dimensional chemistry that is time averaged, single-level, at reduced...

  3. MERRA Chem 2D IAU Diagnostics, Fluxes and Meteorology, Monthly Mean (surface, 1.25x1L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMFXCHM or tavgM_3d_chm_Fx data product is the MERRA Data Assimilation System Chemistry 2-Dimensional chemistry that is time averaged, single-level, at reduced...

  4. Influence of the type of milking and storage of milk on the chem ical composition, Somatic Cell Count and bacterial count Total

    Directory of Open Access Journals (Sweden)

    Aline Leite Peixoto

    2017-03-01

    Full Text Available The refrigeration of milk and the usage of mechanical milking are important to obtain milk in accordance with quality standards. In this work we evaluated the influence of the type of milking process and type of storage on the quality of the refrigerated milk. It was obtained 1363 refrigerated milk samples stored in single or collective expansion tanks, from manually or mechanically milked animals. The experiment was carried out in a 2x2 randomized factorial scheme. Two types of expansion tanks (single and collective and two types of milking (manual and mechanical. The average comparison test and Tukey test was carried out with 95% confidence. The levels of fat, protein, lactose and defatted dry extract, were evaluated according to the type of milking and type of milk storage. The values obtained were higher when compared to the values stabilished by the Ministry of Agriculture, Livestock and Food Supply. The level of milk fat was higher in samples with somatic cell count above 501,000 SC/mL. However, the levels of protein and defatted dry extract were higher in samples with somatic cell count below 500,000 SC/mL. The type of milking and the type of storage have influence on parameters related to milk quality such as levels of fat, protein, lactose and somatic cell count. The milk chemical composition revealed in accordance with the values stabilished by the Brazilian legislation. The total bacterial count did not vary with storage type nor the type of milking.

  5. Clarification of the volumetric properties of the (tetrahydrofuran + water) systems [J. Chem. Thermodyn. 41 (2009) 1382–1386]: Author’s statement

    International Nuclear Information System (INIS)

    Belandria, Veronica; Pimentel-Rodas, Alfredo; Mohammadi, Amir H.; Galicia-Luna, Luis A.; Richon, Dominique

    2013-01-01

    Highlights: ► New experimental density data are reported for the (THF + water) systems. ► A vibrating tube densimeter has been used to perform the measurements. ► A discussion is made on the reliability of the generated data and other questions raised in the literature. - Abstract: Although reliable and consistent volumetric data can be derived from density measurements, the greatest experimental difficulty and largest measurement errors often occur in the very dilute regions of concentration. Such data are of great interest in separation processes where a high degree of purity is required. In this communication, the densities of the (tetrahydrofuran + water) systems have been carefully investigated in dilute regions. A vibrating tube densimeter has been used to perform the measurements. A discussion is made on the reliability of the generated experimental data and the questions raised in the literature.

  6. The Chem-Math Project: Enhancing Success in General Chemistry through the Integration of Mathematics, Problem-Solving and Conceptual Understanding. An Action-Research Study

    Science.gov (United States)

    Kilner, William Cary

    2014-01-01

    Freshmen with declared life-science majors typically matriculate with a determination to succeed. However, inadequately-prepared students are easily overwhelmed and at risk of abandoning their aspirations for a STEM career. The investigator designed and taught weekly recitations for approximately 850 students during a five-year span, and…

  7. Extraction of compositional and hydration information of sulfates from laser-induced plasma spectra recorded under Mars atmospheric conditions - Implications for ChemCam investigations on Curiosity rover

    Energy Technology Data Exchange (ETDEWEB)

    Sobron, Pablo, E-mail: pablo.sobron@asc-csa.gc.ca [Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130 (United States); Wang, Alian [Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130 (United States); Sobron, Francisco [Unidad Asociada UVa-CSIC a traves del Centro de Astrobiologia, Parque Tecnologico de Boecillo, Parcela 203, Boecillo (Valladolid), 47151 (Spain)

    2012-02-15

    Given the volume of spectral data required for providing accurate compositional information and thereby insight in mineralogy and petrology from laser-induced breakdown spectroscopy (LIBS) measurements, fast data processing tools are a must. This is particularly true during the tactical operations of rover-based planetary exploration missions such as the Mars Science Laboratory rover, Curiosity, which will carry a remote LIBS spectrometer in its science payload. We have developed: an automated fast pre-processing sequence of algorithms for converting a series of LIBS spectra (typically 125) recorded from a single target into a reliable SNR-enhanced spectrum; a dedicated routine to quantify its spectral features; and a set of calibration curves using standard hydrous and multi-cation sulfates. These calibration curves allow deriving the elemental compositions and the degrees of hydration of various hydrous sulfates, one of the two major types of secondary minerals found on Mars. Our quantitative tools are built upon calibration-curve modeling, through the correlation of the elemental concentrations and the peak areas of the atomic emission lines observed in the LIBS spectra of standard samples. At present, we can derive the elemental concentrations of K, Na, Ca, Mg, Fe, Al, S, O, and H in sulfates, as well as the hydration degrees of Ca- and Mg-sulfates, from LIBS spectra obtained in both Earth atmosphere and Mars atmospheric conditions in a Planetary Environment and Analysis Chamber (PEACh). In addition, structural information can be potentially obtained for various Fe-sulfates. - Highlights: Black-Right-Pointing-Pointer Routines for LIBS spectral data fast automated processing. Black-Right-Pointing-Pointer Identification of elements and determination of the elemental composition. Black-Right-Pointing-Pointer Calibration curves for sulfate samples in Earth and Mars atmospheric conditions. Black-Right-Pointing-Pointer Fe curves probably related to the crystalline structure of Fe-sulfates. Black-Right-Pointing-Pointer Extraction of degree of hydration in hydrous Mg-, Ca-, and Fe-sulfates.

  8. An Investigation of Aerosol-Cloud-Precipitation Interactions in the South-East Pacific Using DOE G-1 Data and WRF/Chem Large Eddy Simulations

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Sally [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States); Feingold, Graham [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States); Kazil, Jan [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States)

    2015-12-04

    Under this grant, we investigated marine boundary layer clouds, their properties, behavior, and response to human activity and climate change, with a focus on scales and processes that cannot be studied with climate models. Investigated topics and results are summarized in this section. Detailed information are given in subsequent sections, followed by a list of resulting publications.

  9. Development of Short Range Repulsive Inter-Particle Forces in Aqueous Si3N4 Slurries with Chem-Adsorbed Silanes

    National Research Council Canada - National Science Library

    Colic, Miroslav

    1997-01-01

    .... Addition of salt to dispersed silicon nitride slurries with particles coated with polyethyleneglycol-silane, caused the collapse of the 22 atoms long chains and residual electrical double layer...

  10. WRF-Chem simulations in the Amazon region during wet and dry season transitions: evaluation of methane models and wetland inundation maps

    Science.gov (United States)

    Beck, V.; Gerbig, C.; Koch, T.; Bela, M. M.; Longo, K. M.; Freitas, S. R.; Kaplan, J. O.; Prigent, C.; Bergamaschi, P.; Heimann, M.

    2013-08-01

    The Amazon region, being a large source of methane (CH4), contributes significantly to the global annual CH4 budget. For the first time, a forward and inverse modelling framework on regional scale for the purpose of assessing the CH4 budget of the Amazon region is implemented. Here, we present forward simulations of CH4 as part of the forward and inverse modelling framework based on a modified version of the Weather Research and Forecasting model with chemistry that allows for passive tracer transport of CH4, carbon monoxide, and carbon dioxide (WRF-GHG), in combination with two different process-based bottom-up models of CH4 emissions from anaerobic microbial production in wetlands and additional datasets prescribing CH4 emissions from other sources such as biomass burning, termites, or other anthropogenic emissions. We compare WRF-GHG simulations on 10 km horizontal resolution to flask and continuous CH4 observations obtained during two airborne measurement campaigns within the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) project in November 2008 and May 2009. In addition, three different wetland inundation maps, prescribing the fraction of inundated area per grid cell, are evaluated. Our results indicate that the wetland inundation maps based on remote-sensing data represent the observations best except for the northern part of the Amazon basin and the Manaus area. WRF-GHG was able to represent the observed CH4 mixing ratios best at days with less convective activity. After adjusting wetland emissions to match the averaged observed mixing ratios of flights with little convective activity, the monthly CH4 budget for the Amazon basin obtained from four different simulations ranges from 1.5 to 4.8 Tg for November 2008 and from 1.3 to 5.5 Tg for May 2009. This corresponds to an average CH4 flux of 9-31 mg m-2 d-1 for November 2008 and 8-36 mg m-2 d-1 for May 2009.

  11. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    36 and -amyloid (A) are investigated by extensive Brownian dynamics simulations, where the inter amino acid interactions are given by a minimalistic model (MM) we recently introduced [J. Chem. Phys. 118 4733 (2003)]. In this model, a ...

  12. Atmospheric aerosol characteristics retrieved using ground based ...

    Indian Academy of Sciences (India)

    negative in summer due to enhanced tourists' arrival and also in autumn months due to the month- long International .... ces due to socio-economic activities, population growth ...... in aerosol optical properties over China; Atmos. Chem. Phys.

  13. On the origin of spurious errors in many-body expansion for water ...

    Indian Academy of Sciences (India)

    SOUMEN SAHA

    lized in various significant methodological approaches. However, since ..... CSIR, New Delhi is thanked for financial support in the form of GENESIS (BSC-121), a 12th five year Plan project. GNS .... II. accuracy considerations J. Chem. Phys.

  14. Some concepts in condensed phase chemical kinetics

    International Nuclear Information System (INIS)

    Adelman, S.A.

    1986-01-01

    Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms

  15. Untitled

    Indian Academy of Sciences (India)

    Metropolis N, Rosenblueth A, Rosenblueth M, Teller A and Teller E 1953 Equation of state calculations by fast computing machines; J. Chem. Phys, 21 1087-1092 ... its properties and use for automated interpretation; Geophysics 37 507-517 y.

  16. NSSEFF COMPUTATIONAL AND THEORETICAL DESIGN OF PHOTO AND MECHANORESPONSIVE MOLECULAR DEVICES

    Science.gov (United States)

    2016-11-10

    piston ). Once we discovered reactions in this way, we realized that the reactions could then be studied with...Cluster Singles and Doubles via Tensor Hypercontraction: THC-CC2," J. Chem. Phys. 138, 124111 (2013). 26. E.G. Hohenstein, S.I.L. Kokkila, R.M...Singles and Doubles via Orbital-Weighted Least-Squares Tensor Hypercontraction," J. Chem. Phys. 140, 181102 (2014). 29. R.M. Parrish, E.G.

  17. Excess molar volumes and viscosities of binary mixtures of some ...

    Indian Academy of Sciences (India)

    Unknown

    ... H T S, Aralaguppi M I and. Hansen K C 1994 J. Chem. Eng. Data 39 251. 43. Pal A and Kumar H 2001 Fluid Phase Equilibria 181 17. 44. Reed T M III and Taylor T E 1959 J. Phys. Chem. 63 58. 45. Meyer R, Meyer J, Metzer J and Peneloux A 1971 J. Chim. Phys. 68 406. 46. Palepu R, Oliver J and Mackinnon B 1985 Can.

  18. Symposium on Molecular Spectroscopy (39th) Held in Columbus, Ohio on 11-15 Jun 84.

    Science.gov (United States)

    1984-06-15

    02139; R. BACIS, and S. CHURASSY, Laboratoire de Spectrometrie lonique et Moleculaire, Universit Claude Bernard (Lvon 1), 69622 Villeurbanne, France. r...Spectrometrie * lonique et Moleculaire, Universite Claude Bernard -Lyon I, 69622 Villeurbanne, - France; C. LINTON, Department of Physics, University of New...National Bureau of Standards. 3. S. Muenter and W. Klemperer, J. Chem. Phys. 52, 6033 (1970). 20. K. Hindermann and C. D. Cornwell , J. Chem. Ph-ys. 48

  19. Fulltext PDF

    Indian Academy of Sciences (India)

    TECS

    (a) Gearheart L A, Somoza M M, Rivers W E, Mur- phy C J, Coleman R S and Berg M A 2003 J. Am. Chem. Soc. 125 11812; (b) Brauns E B, Madaras M. L, Coleman R S and Berg M A 2002 Phys. Rev. Lett. 88 158101-1-4. 19. Frauchiger L, Shirota H, Uhrich K E and Castner E. W Jr 2002 J. Phys. Chem. B106 7463. 20.

  20. Exploring the High-Pressure Behavior of PETN: A Combined Quantum Mechanical and Experimental Study

    Science.gov (United States)

    2006-11-01

    calculations to explore the hypothesized compression-induced polymorphic phase transition [Gruzdkov 2004]. The initial crystal in these Figure 4...Scuseria, G.E., and Chabalowski, C.F. 2004: An ab Initio Study of Solid Nitromethane, HMX , RDX , and CL20: Successes and Failures of DFT. J. Phys. Chem... RDX , HMX , HNIW, and PETN Crystals. J. Phys. Chem. B, 103, 6783. Trotter, J., 1963: Bond lengths and angles in Pentaerythritol Tetranitrate. Acta

  1. Calculation of Kinetic Data for Processes Leading to UV Signatures

    Science.gov (United States)

    1989-03-31

    Jv we make use of the numerical algorithm developed by Stodden and Micha 17, extending it to the equations of motion in curvilinear coordinates. To be...in the field of the average potential V(Q). The set of equations (4.13’) have been recently derived by Stodden and Michat 5 in a more tedious.way by...B. Bloom, J. Chem. Phys. 83, 5703 (1985) 5 P. K. Swamninathan, C. D. Stodden , and D. A. Micha, J. Chem. Phys., in press (1989). 6 R. A. Marcus, Chem

  2. Exploring the Structure of Nitrogen-Rich Ionic Liquids and Their Binding to the Surface of Oxide-Free Boron Nanoparticles

    Science.gov (United States)

    2013-01-29

    results have to be interpreted with caution. Lovelock et al.61 have shown that clean surfaces can be obtained by sputtering for the [CnC1Im][Tf2N] IL...Licence, P. Langmuir 2006, 22, 9386−9392. (58) Hurisso, B. B.; Lovelock , K. R.; Licence, P. Phys. Chem. Chem. Phys. 2011, 13, 17737−48. (59) Zhang, H.; Cui...H. Langmuir 2009, 25, 2604−2612. (60) Zhang, Q.; Ma, X.; Liu, S.; Yang, B.; Lu, L.; He, Y.; Deng, Y. J. Mater. Chem. 2011, 21, 6864. (61) Lovelock , K

  3. Improving Science Teacher Preparation through the APS PhysTEC and NSF Noyce Programs

    Science.gov (United States)

    Williams, Tasha; Tyler, Micheal; van Duzor, Andrea; Sabella, Mel

    2013-03-01

    Central to the recruitment of students into science teaching at a school like CSU, is a focus on the professional nature of teaching. The purpose of this focus is twofold: it serves to change student perceptions about teaching and it prepares students to become teachers who value continued professional development and value the science education research literature. The Noyce and PhysTEC programs at CSU place the professional nature of teaching front and center by involving students in education research projects, paid internships, attendance at conferences, and participation in a new Teacher Immersion Institute and a Science Education Journal Reading Class. This poster will focus on specific components of our teacher preparation program that were developed through these two programs. In addition we will describe how these new components provide students with diverse experiences in the teaching of science to students in the urban school district. Supported by the NSF Noyce Program (0833251) and the APS PhysTEC Program.

  4. Resonance Fluorescence of a Two-Level Atom Near a Metal Surface. II. Case of a Strong Driving Field,

    Science.gov (United States)

    1984-02-01

    XYH thanks Prof. M. G. Raymer for a useful discussion. REFERENCES 1. X. Y. Huang, J. Lin and T. F. George, J. Chem. Phys., 80, 893 (1984). 2. X. Y...Mollow, Phys. Rev. A, 15, 1023 (1977). 12. J. L. Carlsten, A. Sz6ke and M. G. Raymer , Phys. Rev. A, 15, 1029 (1977). 13. H. Kuhn, J. Chem. Phys. 53, 101...Evanston, Illinois 60201 Austin, Texas 78712 Dr. Robert M. Hexter Dr. R. P. Van Duyne Department of Chemistry Chemistry Department University of Minnesota

  5. A virtual test of screening technology based on the AGEIA PhysX

    Energy Technology Data Exchange (ETDEWEB)

    Ai-min Li; Rui-ling Lv; Chu-sheng Liu [China University of Mining and Technology, Xuzhou (China). School of Mechanical and Electrical Engineering

    2008-06-15

    The authors have created a virtual test of vibration particle-screening using Autodesk's 3ds Max software, the MAXScript scripting language and the AGEIA PhysX physics processing unit (PPU). The affect of various parameters on screening efficiency were modeled. The parameters included vibration amplitude, frequency and direction. The length and inclination of the vibrating surface were also varied. The virtual experiment is in basic agreement with results predicted from screening theory. This shows that the virtual screener can be used for preliminary investigations and the results used to evaluate screen design. In addition it can help with theoretical research. 11 refs., 7 figs., 7 tabs.

  6. Comment on “Effects of damping solitary wave in a viscosity bounded plasma” [Phys. Plasmas 21, 022118 (2014)

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Uday Narayan, E-mail: unghosh1@rediffmail.com; Chatterjee, Prasanta; Roychoudhury, Rajkumar [Department of Mathematics, Siksha Bhavana, Visva Bharati, Santiniketan 731235 (India)

    2015-07-15

    Recently Gun Li et al. discussed “Effects of damping solitary wave in a viscosity bounded plasma” [Phys. Plasmas 21, 022118 (2014)]. The paper contains some serious errors which have been pointed out in this Comment.

  7. PyDecay/GraphPhys: A Unified Language and Storage System for Particle Decay Process Descriptions

    Energy Technology Data Exchange (ETDEWEB)

    Dunietz, Jesse N.; /MIT /SLAC

    2011-06-22

    To ease the tasks of Monte Carlo (MC) simulation and event reconstruction (i.e. inferring particle-decay events from experimental data) for long-term BaBar data preservation and analysis, the following software components have been designed: a language ('GraphPhys') for specifying decay processes, common to both simulation and data analysis, allowing arbitrary parameters on particles, decays, and entire processes; an automated visualization tool to show graphically what decays have been specified; and a searchable database storage mechanism for decay specifications. Unlike HepML, a proposed XML standard for HEP metadata, the specification language is designed not for data interchange between computer systems, but rather for direct manipulation by human beings as well as computers. The components are interoperable: the information parsed from files in the specification language can easily be rendered as an image by the visualization package, and conversion between decay representations was implemented. Several proof-of-concept command-line tools were built based on this framework. Applications include building easier and more efficient interfaces to existing analysis tools for current projects (e.g. BaBar/BESII), providing a framework for analyses in future experimental settings (e.g. LHC/SuperB), and outreach programs that involve giving students access to BaBar data and analysis tools to give them a hands-on feel for scientific analysis.

  8. Phys FilmMakers: teaching science students how to make YouTube-style videos

    Science.gov (United States)

    Coates, Rebecca L.; Kuhai, Alvina; Turlej, Laurence Z. J.; Rivlin, Tom; McKemmish, Laura K.

    2018-01-01

    Phys FilmMakers (PFM) is a new type of course in which a science expert and science communicator partner teach physics students how to make YouTube-style videos on cutting-edge scientific research within the university department. Here, we describe this new course, outline its key components and provide recommendations for others considering implementing a similar FilmMakers-style course using feedback from course tutors and students. We discuss successful and less successful teaching techniques as well as use our experience to identify areas that science students in particular often have difficulties: finding an interesting ‘hook’ for the video, imagining creative B-roll and making a succinct video by removing extraneous (though usually correct and often interesting) material. The course has two major components: workshop sessions in which students learn the key elements of film-making and independent video production where PFM students partner with senior PhD or post-doc researchers to produce a video on their research. This partnership with the department means that the videos produced serve not only as interesting ‘edutainment’ to encourage teenagers and young adults into Science, Technology, Engineering and Maths subjects, but also provide valuable outreach for the academic department.

  9. ARPA-NRL Laser Program - Semiannual Technical Report to Defense Advanced Research Projects Agency, 1 January 1974-30 June 1974

    Science.gov (United States)

    1975-04-01

    Johnson and R.G, Fijw!’r, I. Chem. I’hys P. Millet , i. Salamero, n. Brunei, J. Goly, Ü. Bl.inc, and J, L. fuysslri...Chem Phys. 53, 1004 (1970). i «. wnem. ’Reference 4. ’P. Millet , Y. Salamero, H. Brunei, ,1. Galv. D. Blanc and J.L. reysster, J, Chem...1973) . 7. N. Djeu and R. Burnham, to be published. 8. P. Jean , M. Martin, J.P. Barrat, and J.L. Cojan, Compt. Rend. 264B, 609 (1967). 9. J.P

  10. Electron and Hole Behavior in Powdered TiO2 - Photoluminescence and Infrared Studies

    Science.gov (United States)

    2014-04-01

    and Selected Results. Chem. Rev. 1995, 95, 735-758. 6. Goswami, D. Y., A Review of Engineering Developments of Aqueous Phase Solar Photocatalytic...B., Surface-Bound Carbonyl - Compounds as Lewis-Acids - Photoluminescence as a Probe for the Binding of Ketones and Aldehydes to Cadmium-Sulfide and...Photoassisted Reaction of Water/ Methanol Mixture. J. Phys. Chem. C 2007, 111, 693-699. 51. Nakajima, H.; Itoh, K.; Murabayashi, M., Influences of C-1-C-3

  11. (nitro substituted-phenyl)-hydrazonomethyl

    Indian Academy of Sciences (India)

    7.14 (d, 1H, ArH), δ 7.36 (m, 2H, ArH), δ 7.47–7.51 (m,. 2H, ArH), δ 7.77 ..... Phys. Chem. A 115 1985; (d) Kang Y, Gwon K, Shin J H, ... (a) Zhang J F, Lim C S, Bhuniya S, Cho B R and Kim. J S 2011 Org. ... Chem. Rev. 240 1; (c) Sessler J L and.

  12. Growth of CdS nanoparticles by chemical method and its ...

    Indian Academy of Sciences (India)

    carbon film supported on the copper grid and was kept for some time for drying. Transmission electron ... Wang et al obtained CdS nanoparticles having a band gap of. 2.79 eV [21]. .... [16] S Yu, Y Wu, J Yang, Z Han, Y Quan, X Liu and Y Xie, Chem. Matter 10 ... [22] U K Gautam, R Seshadri and C N R Rao, Chem. Phys. Lett.

  13. Rate Processes in Dissipative Systems: 50 Years After Kramers, Discussion Meeting Held in Tutzing (Germany, F.R.) on 10-13 September 1990

    Science.gov (United States)

    1990-09-13

    Chem. Soc., Faraday Trans. [5] S. T. Abdel-Halim, M. H. Abdel-Kader, and U. E. Steiner , J. 2, 83, 1941 (1987), Phys. Chem 92, 4324 (1988). [29] W...December 5th, 1990) Zusammensetzung, Eigenschaften und Anwendungen Mesomorpher Tensidphasen RUDOLF HEUSCH Leverkusen, Paul-Klee-StraBe 85 (Received on...Institut f~r Anorganisehe Chemnie der Universitiit Rudower Chaussee 5, 0-1199 Physikalisehe Chemie) Rudolf - Bern, Freie Stra~e 3, CH-3000 Bern, be- Berlin

  14. Resonance Fluorescence of Many Interacting Adatoms at a Metal Surface.

    Science.gov (United States)

    1983-06-01

    we must know the complex function f(d , which can be determined by the Sommerfeld-Hertz vector procedure,2 M 2 1 24 ,+ 2 sp (W p W2 CA) 4 62 {-L...Chem. Phys. 37: 1 (1978). 6. J. H. Eberly, Atomic Relaxation in the Presence of Intense Partially Coherent Radiation Feilds , Phys. Rev. Lett. 37

  15. Role of the first coordination shell in determining the equilibrium structure and dynamics of simple liquids

    DEFF Research Database (Denmark)

    Toxværd, Søren; Dyre, J. C.

    2011-01-01

    . Lett. 103, 170601 (2009);10.1103/PhysRevLett.103.170601 J. Chem. Phys. 134, 214503 (2011)10.1063/1.3592709] . We present simulations of the standard Lennard-Jones liquid at several condensed-fluid state points, including a fairly low density state and a very high density state, as well as simulations...

  16. PhysTrack’: a Matlab based environment for video tracking of kinematics in the physics laboratory

    Science.gov (United States)

    Umar Hassan, Muhammad; Sabieh Anwar, Muhammad

    2017-07-01

    In the past two decades, several computer software tools have been developed to investigate the motion of moving bodies in physics laboratories. In this article we report a Matlab based video tracking library, PhysTrack, primarily designed to investigate kinematics. We compare PhysTrack with other commonly available video tracking tools and outline its salient features. The general methodology of the whole video tracking process is described with a step by step explanation of several functionalities. Furthermore, results of some real physics experiments are also provided to demonstrate the working of the automated video tracking, data extraction, data analysis and presentation tools that come with this development environment. We believe that PhysTrack will be valuable for the large community of physics teachers and students already employing Matlab.

  17. Comment on “Temperature dependence of atomic vibrations in mono-layer graphene” [J. Appl. Phys. 118, 074302 (2015)

    International Nuclear Information System (INIS)

    Susi, T.; Kotakoski, J.

    2016-01-01

    In an interesting recent study [Allen et al., J. Appl. Phys. 118, 074302 (2015)] (see also their Erratum [Allen et al., J. Appl. Phys. 118, 159902 (2015)]), Allen and co-workers measured the mean square amplitudes of graphene lattice vibrations between 100 and 1300 K and used a simplified theoretical approximation for the acoustic phonon modes to evaluate the maximum phonon wavelengths supported by the lattice. By fitting their data using the smallest wave-vector as the fitting parameter, they found this to be significantly smaller than the physical size of the graphene crystallites

  18. Comment on : "A novel approach for solving the Fisher equation using Exp-function method" [Phys. Lett. A 372 3836

    NARCIS (Netherlands)

    Kudryashov, Nikolai A.

    2009-01-01

    Using Exp-function method Ozis and Koroglu [T. Ozis, C. Koroglu, Phys. Lett. A 372 (2008) 3836] have found exact "solutions" of the Fisher equation. In this comment we demonstrate that all these solutions do not satisfy the Fisher equation. The efficiency of application of Exp-function method to

  19. Comments on ''theory of dissipative density-gradient-driven turbulence in the tokamak edge'' [Phys. Fluids 28, 1419 (1985)

    International Nuclear Information System (INIS)

    Krommes, J.A.

    1985-11-01

    The author critiques the model of tokamak edge turbulence by P.W. Terry and P.H. Diamond (Phys. Fluids 28, 1419, 1985). The critique includes a discussion of the physical basis, consistency and quantitative accuracy of the Terry-Diamond model. 19 refs

  20. The analysis of senior high school students' physics HOTS in Bantul District measured using PhysReMChoTHOTS

    Science.gov (United States)

    Istiyono, Edi

    2017-08-01

    The purpose of this research is to describe the results of higher order thinking skills in physics (PhysHOTS) measurement including: (1) percentage of PhysHOTS level and (2) percentage of the domination of response in the category of students in each analyzing, evaluating, and creating skill. There were 404 10th grade students in Bantul District as the respondents of this research. The instrument used for measurement was PhysReMChoTHOTS. It was divided into two sets consisting of 44 items and including 8 anchor items stated valid by a Physicist, Physics Education Expert, and Physics Education Measurement Expert. The instrument was fit to PCM. The reliability coefficient of this test is 0.71, while the difficulty index of the items ranges from -0.61 to 0.51. The results of the measurement show that: (1) The percentage of each category of PhysHOTS for the 10th grade students in Bantul District for the very low, low, medium, high, and very high category is 4.75 %, 40.30 %, 33.45 %, 19.50 %, and 2.00 %, respectively; and (2) The order in analyzing skills, starts from the weakest, is attributing, differentiating and organizing. The order in evaluating skills, starts from the weakest, is critiquing and checking. Meanwhile, the order in creating skills, starts from the weakest, is producing, planning, and generating.

  1. Characterization and H2-O2 reactivity of noble nano-metal tailored single wall nano-carbons

    International Nuclear Information System (INIS)

    K Kaneko; T Itoh; E Bekyarova; H Kanoh; S Utsumi; H Tanaka; M Yudasaka; S Iijima; S Iijima

    2005-01-01

    Full text of publication follows: Single wall carbon nano-tube (SWNT) and single wall carbon nano-horn (SWNH) have nano-spaces in their particles and the nano-spaces become open by oxidation. In particular, SWNH forms a unique colloidal structure which has micropores and meso-pores between the SWNH particles. Although non-treated SWNH colloids have quasi-one dimensional nano-pores [1], oxidized SWNH colloids have both of interstitial and internal nano-pores [2-5]. SWNH colloids show excellent supercritical methane storage ability [6], molecular sieving effect [7], and unique hydrogen adsorption characteristic [8]. Selective adsorptivity of SWNH colloids for H 2 and D 2 due to uncertainty principle of those molecules was shown [9-10]. As SWNH has no metallic impurities, we can study the effect of tailoring of metallic nano-particles on the surface activities of SWNH [11]. We tailored Pd or Pt nano-particles on SWNH and SWNH oxidized at 823 K (ox-SWNH) using poly[(2-oxo-pyrrolidine-1-yl)ethylene]. The oxidation of SWNH donates nano-scale windows to the single wall. The tailored metal amount was determined by TG analysis. TEM showed uniform dispersion of nano-metal particles of 2-3 nm in the diameter on SWNH. The nitrogen adsorption amount of SWNH oxidized decreases by tailoring, indicating that nano-particles are attached to the nano-scale windows. The electronic states of tailored metals were characterized by X-ray photoelectron spectroscopy. The surface activities of Pd tailored SWNH and ox-SWNH were examined for the reaction of hydrogen and oxygen near room temperature. The catalytic reactivities of Pd tailored SWNH and ox-SWNH were 4 times greater than that of Pd-dispersed activated carbon. The temperature dependence of the surface activity will be discussed with the relevance to the tube porosity. References [1] T. Ohba et al, J. Phys. Chem. In press. [2] S. Utsumi et al, J. Phys. Chem. In press. [3] C.- Min Yang, et al. Adv. Mater. In press. [4]C.M. Yang, J

  2. Response to 'Comment on 'Ultrafast electron optics: Propagation dynamics of femtosecond electron packets'' [J. Appl. Phys. 94, 803 (2003)

    International Nuclear Information System (INIS)

    Siwick, Bradley J.; Dwyer, Jason R.; Jordan, Robert E.; Miller, R. J. Dwayne

    2003-01-01

    In this reply, we address the main issues raised by Qian et al. regarding our recent article [J. Appl. Phys. 92, 1643 (2002)]. In particular, we reiterate the approximations used in the development of the mean-field model and demonstrate how the form used for the on-axis potential is applicable to the study of femtosecond electron packet propagation and is not in need of correction. We also repeat our assertion that the one-dimensional (1-D) fluid model developed by Qian et al. [J. Appl. Phys. 91, 462 (2002)] overestimates space-charge-induced pulse broadening and is in qualitative disagreement with femtosecond electron packet propagation dynamics. The key differences between the mean-field and 1-D fluid model are discussed and their range of applicability is clarified

  3. Comment on “Maxwell's equations and electromagnetic Lagrangian density in fractional form” [J. Math. Phys. 53, 033505 (2012)

    International Nuclear Information System (INIS)

    Rabei, Eqab M.; Al-Jamel, A.; Widyan, H.; Baleanu, D.

    2014-01-01

    In a recent paper, Jaradat et al. [J. Math. Phys. 53, 033505 (2012)] have presented the fractional form of the electromagnetic Lagrangian density within the Riemann-Liouville fractional derivative. They claimed that the Agrawal procedure [O. P. Agrawal, J. Math. Anal. Appl. 272, 368 (2002)] is used to obtain Maxwell's equations in the fractional form, and the Hamilton's equations of motion together with the conserved quantities obtained from fractional Noether's theorem are reported. In this comment, we draw the attention that there are some serious steps of the procedure used in their work are not applicable even though their final results are correct. Their work should have been done based on a formulation as reported by Baleanu and Muslih [Phys. Scr. 72, 119 (2005)

  4. Reply to ''Comment on 'Transmit versus receive gains for microwave dish antennas' [J. Appl. Phys. 54, 3528 (1983)]''

    International Nuclear Information System (INIS)

    Richter, J.L.

    1985-01-01

    A. W. Love points out three alleged errors in our paper [J. Appl. Phys. 54, 3528 (1983)]. We agree that he is correct with regard to the second and third issues, but the first and perhaps most important point is correct. This regards the inequality of transmit and receive patterns of microwave antennas. The standard proof of equality of the patterns, cited by A. W. Love, is shown to be incorrect

  5. Comment on "Total Negative Refraction in Real Crystals for Ballistic Electrons and Light" (Phys. Rev. Lett. 91, 157404 (2003))

    OpenAIRE

    Yau, H. -F.; Liu, J. -P.; Ke, B.; Kuo, C. -H.; Ye, Z.

    2003-01-01

    Recently, Zhang et al. (Phys. Rev. Lett. 91, 157404 (2003)) have demonstrated that an amphoteric refraction, i. e. both positive and negative refraction, may prevail at the interface of two uniaxial anisotropic crystals when their optical axes are in different directions. The authors subsequently made a correspondence between such a refraction with the negative refraction expected for Left Handed Materials (LHMs). Here we comment that the amphoteric refraction can be observed even with one un...

  6. Retraction: On the origin of power-law distributions in systems with constrained phase space [Condens. Matter Phys., 2013, vol. 16, 43802

    Directory of Open Access Journals (Sweden)

    Editorial Board

    2014-03-01

    Full Text Available The article Condens. Matter Phys., 2013, vol. 16, 43802 ( DOI:10.5488/CMP.16.43802 has been retracted by the decision of the Editorial Board. There is a significant overlap with an article: Phys. Rev. E, 2006, vol. 74, 036120 ( DOI:10.1103/PhysRevE.74.036120. Appologies are offered to readers of the journal that this was not detected during the submission process.

  7. State resolved rotational excitation cross-sections and rates in H2 + H2 collisions

    International Nuclear Information System (INIS)

    Sultanov, Renat A.; Guster, Dennis

    2006-01-01

    Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H 2 -H 2 system are used from the following works: [A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J. Peterson, J. Chem. Phys., 116 (2002) 666; P. Diep, J.K. Johnson, J. Chem. Phys., 113 (2000) 3480; P. Diep, J.K. Johnson, J. Chem. Phys., 112 (2000) 4465]. Cross-sections for rotational transitions 00 → 20, 22, 40, 42, 44 and corresponding rate coefficients are calculated using a quantum-mechanical approach. Results are compared for a wide range of kinetic temperatures 300 K ≤ T≤ 3000 K

  8. The role of the excited electronic states in the C++H2O reaction

    International Nuclear Information System (INIS)

    Flores, Jesus R.; Gonzalez, Adan B.

    2008-01-01

    The electronic excited states of the [COH 2 ] + system have been studied in order to establish their role in the dynamics of the C + +H 2 O→[COH] + +H reaction, which is a prototypical ion-molecule reaction. The most relevant minima and saddle points of the lowest excited state have been determined and energy profiles for the lowest excited doublet and quartet electronic states have been computed along the fragmentation and isomerization coordinates. Also, nonadiabatic coupling strengths between the ground and the first excited state have been computed where they can be large. Our analysis suggests that the first excited state could play an important role in the generation of the formyl isomer, which has been detected in crossed beam experiments [D. M. Sonnenfroh et al., J. Chem. Phys. 83, 3985 (1985)], but could not be explained in quasiclassical trajectory computations [Y. Ishikawa et al., Chem. Phys. Lett. 370, 490 (2003); J. R. Flores, J. Chem. Phys. 125, 164309 (2006)

  9. Magnetic exchange couplings from noncollinear perturbation theory: dinuclear CuII complexes.

    Science.gov (United States)

    Phillips, Jordan J; Peralta, Juan E

    2014-08-07

    To benchmark the performance of a new method based on noncollinear coupled-perturbed density functional theory [J. Chem. Phys. 138, 174115 (2013)], we calculate the magnetic exchange couplings in a series of triply bridged ferromagnetic dinuclear Cu(II) complexes that have been recently synthesized [Phys. Chem. Chem. Phys. 15, 1966 (2013)]. We find that for any basis-set the couplings from our noncollinear coupled-perturbed methodology are practically identical to those of spin-projected energy-differences when a hybrid density functional approximation is employed. This demonstrates that our methodology properly recovers a Heisenberg description for these systems, and is robust in its predictive power of magnetic couplings. Furthermore, this indicates that the failure of density functional theory to capture the subtle variation of the exchange couplings in these complexes is not simply an artifact of broken-symmetry methods, but rather a fundamental weakness of current approximate density functionals for the description of magnetic couplings.

  10. Comment on “Theoretical analysis of high-field transport in graphene on a substrate” [J. Appl. Phys. 116, 034507 (2014)

    International Nuclear Information System (INIS)

    Tan, Michael L. P.; Arora, Vijay K.

    2014-01-01

    In a recent article, Serov et al. [J. Appl. Phys. 116, 034507 (2014)] claim: “This study represents the first time that the high-field behavior in graphene on a substrate was investigated taking into account intrinsic graphene properties,” ignoring the most recent anisotropic distribution function [V. K. Arora et al., J. Appl. Phys. 112, 114330 (2012)] also published in J. Appl. Phys., targeting the same experimental data [V. E. Dorgan et al., Appl. Phys. Lett. 97, 082112 (2010)]. The claim of Serov et al. of being first is refuted and many shortcomings of the hydrodynamic model for a highly quantum and degenerate graphene nanolayer are pointed out

  11. Hydrogen adsorption strength and sites in the metal organic framework MOF5: Comparing experiment and model calculations

    Science.gov (United States)

    Mulder, F. M.; Dingemans, T. J.; Schimmel, H. G.; Ramirez-Cuesta, A. J.; Kearley, G. J.

    2008-07-01

    Hydrogen adsorption in porous, high surface area, and stable metal organic frameworks (MOF's) appears a novel route towards hydrogen storage materials [N.L. Rosi, J. Eckert, M. Eddaoudi, D.T. Vodak, J. Kim, M. O'Keeffe, O.M. Yaghi, Science 300 (2003) 1127; J.L.C. Rowsell, A.R. Millward, K. Sung Park, O.M. Yaghi, J. Am. Chem. Soc. 126 (2004) 5666; G. Ferey, M. Latroche, C. Serre, F. Millange, T. Loiseau, A. Percheron-Guegan, Chem. Commun. (2003) 2976; T. Loiseau, C. Serre, C. Huguenard, G. Fink, F. Taulelle, M. Henry, T. Bataille, G. Férey, Chem. Eur. J. 10 (2004) 1373]. A prerequisite for such materials is sufficient adsorption interaction strength for hydrogen adsorbed on the adsorption sites of the material because this facilitates successful operation under moderate temperature and pressure conditions. Here we report detailed information on the geometry of the hydrogen adsorption sites, based on the analysis of inelastic neutron spectroscopy (INS). The adsorption energies for the metal organic framework MOF5 equal about 800 K for part of the different sites, which is significantly higher than for nanoporous carbon materials (˜550 K) [H.G. Schimmel, G.J. Kearley, M.G. Nijkamp, C.T. Visser, K.P. de Jong, F.M. Mulder, Chem. Eur. J. 9 (2003) 4764], and is in agreement with what is found in first principles calculations [T. Sagara, J. Klassen, E. Ganz, J. Chem. Phys. 121 (2004) 12543; F.M. Mulder, T.J. Dingemans, M. Wagemaker, G.J. Kearley, Chem. Phys. 317 (2005) 113]. Assignments of the INS spectra is realized using comparison with independently published model calculations [F.M. Mulder, T.J. Dingemans, M. Wagemaker, G.J. Kearley, Chem. Phys. 317 (2005) 113] and structural data [T. Yildirim, M.R. Hartman, Phys. Rev. Lett. 95 (2005) 215504].

  12. Watching Conformations of Biomolecules: a Microwave Spectroscopy Approach

    Science.gov (United States)

    Lopez, J. C.

    2011-06-01

    The combination of laser ablation with Fourier transform microwave spectroscopy in supersonic jets (LA-MB-FTMW) has made possible the gas-phase study of solid biomolecules with high melting points. In the experiment, solids are efficiently vaporized by a high-energy laser pulse, supersonically expanded into a evacuated Fabry-Perot cavity and characterised by their rotational spectra. Recent improvements such as the use of picosecond pulse lasers, new ablation nozzles and the extension of the range of the spectrometers to low frequecy have notably increased the sensitivity of our experimental setup. To date different α-, β- and γ-amino acids have been studied using this technique, making possible the characterization of their preferred conformations and gaining insight in the role of intramolecular interactions. Even in conformationally challenging systems the different rotamers of such biomolecules can be identified by rotational spectroscopy as can be illustrated by the assignment of six low-energy conformers in cysteine and aspartic acid, seven in serine and threonine,^a and nine in γ-amino butyric acid (GABA). In all cases the low-energy conformers have been conclusive identified from their experimental rotational and 14N quadrupole coupling constants. The spectra of neurotransmitters and of the nucleic acid bases uracil, thymine, cytosine and guanine have also been studied and their preferred conformers or tautomeric forms determined. The complexes between amino acids and nucleic acid bases with water have also been investigated to obtain information on the possible changes induced in the conformational or tautomeric preferences by the addition of solvent molecules. J. L. Alonso, C. Pérez, M. E. Sanz, J. C. López, S. Blanco, Phys. Chem. Chem. Phys. 11, 617-627 (2009) and references therein M. E. Sanz, J. C. López, J. L. Alonso, Phys. Chem. Chem. Phys., 12, 3573-3578 (2010) S. Blanco, J. C. López, S. Mata and J. L. Alonso, Angew. Chem. Int. Ed. 49, 9187

  13. Catalytic Activity and Structure Properties of Doped VOHPO4 ·0.5H2O with Nanosized Ru, Au, Fe and Mn in Benzene Hydroxylation

    CSIR Research Space (South Africa)

    Makgwane, PR

    2013-01-01

    Full Text Available . Taufiq-Yap, S. Nor Asrina, G. J. Hutchings, N. F. Dummer, and J. K. Bartley, J. Natural Gas 162, 31 (1996). 26. M. Choi, C. Han, I. T. Kim, J. C. An, J. J. Lee, H. K. Lee, and J. Shim, J. Nanosci. Nanotechnol. 11, 838 (2011). 27. K. Ki-Joong, S. Jae-Koon.... Today 111, 22 (2006). 35. R. Tanner, P. Gill, R. Wells, J. E. Bailie, G. Kelly, S. D. Jackson, and G. J. Hutchings, Phys. Chem. Chem. Phys. 2, 688 (2002). 36. C.-C. Yang, Y.-J. Lee, and J. M. Yang, J. Power Sources 188, 30 (2009). Received: 31 October...

  14. Interface of the polarizable continuum model of solvation with semi-empirical methods in the GAMESS program

    DEFF Research Database (Denmark)

    Svendsen, Casper Steinmann; Blædel, Kristoffer L.; Christensen, Anders Steen

    2013-01-01

    An interface between semi-empirical methods and the polarized continuum model (PCM) of solvation successfully implemented into GAMESS following the approach by Chudinov et al (Chem. Phys. 1992, 160, 41). The interface includes energy gradients and is parallelized. For large molecules such as ubiq......An interface between semi-empirical methods and the polarized continuum model (PCM) of solvation successfully implemented into GAMESS following the approach by Chudinov et al (Chem. Phys. 1992, 160, 41). The interface includes energy gradients and is parallelized. For large molecules...

  15. Nonadiabatic Eigenfunctions Can Have Amplitude, Signed Conical Nodes, or Signed Higher Order Nodes at a Conical Intersection with Circular Symmetry (Open Access Publisher’s Version)

    Science.gov (United States)

    2017-09-26

    marked by black rings on the potential energy surfaces. In some sense, only about half of the zero point energy is available to each of the two...wheel at the bottom. The conical intersection at q1 = q2 = 0 and E = 0 is submerged below the zero-point energy of Ezp = 181 cm −1 ( black curve). The...J. Chem. Phys. 123, 044102 (2005)]. J. Chem. Phys. 2008, 128, 109902. (49) Clinton, W. L.; Rice , B. Reformulation of the Jahn-Teller Theorem. J

  16. Investigation of ZPE and temperature effects on the Eley-Rideal recombination of hydrogen atoms on graphene using a multidimensional graphene-H-H potential

    Science.gov (United States)

    Sizun, M.; Bachellerie, D.; Aguillon, F.; Sidis, V.

    2010-09-01

    We study the Eley-Rideal recombination of H atoms on graphene under the physical conditions of the interstellar medium. Effects of the ZPE motions of the chemisorbed H atom and of the graphene thermal motions are investigated. Classical molecular dynamics calculations undertaken with the multidimensional potential of Bachellerie et al. [Phys. Chem. Chem. Phys. 11 (2009) 2715] are reported. The ZPE effects are the strongest. The closer the collision energy is to the classical reaction threshold the more sizeable the effects. The quantum reaction cross section is also estimated below and above the classical threshold using a capture model.

  17. Unraveling the Nature of Chemical Reactivity of Complex Systems

    Science.gov (United States)

    2009-01-13

    28 J. Zhou, J. J. Lin, W. Shiu, and K. Liu, J. Chem. Phys. 119, 4997 2003. 29 S. C. Althorpe, F. Fernandez - Alonso , B. D. Bean, J. D. Ayers, A. E...Truhlar DG, Espinosa- Garcia J (2000) Potential energy surface, thermal, and state-selected rate coefficients, and kinetic isotope effects for Cl CH43...HCl CH3. J Chem Phys 112:9375–9389. 22. Rangel C, Navarrete M, Corchado JC, Espinosa- Garcia J (2006) Potential energy surface, kinetics, and

  18. Rotational Spectroscopy Unveils Eleven Conformers of Adrenaline

    Science.gov (United States)

    Cabezas, C.; Cortijo, V.; Mata, S.; Lopez, J. C.; Alonso, J. L.

    2013-06-01

    Recent improvements in our LA-MB-FTMW instrumentation have allowed the characterization of eleven and eight conformers for the neurotransmitters adrenaline and noradrenaline respectively. The observation of this rich conformational behavior is in accordance with the recent observation of seven conformers for dopamine and in sharp contrast with the conformational reduction proposed for catecholamines. C. Cabezas, I. Peña, J. C. López, J. L. Alonso J. Phys. Chem. Lett. 2013, 4, 486. H. Mitsuda, M. Miyazaki, I. B. Nielsen, P. Carcabal,C. Dedonder, C. Jouvet, S. Ishiuchi, M. Fujii J. Phys. Chem. Lett. 2010, 1, 1130.

  19. Response to 'Comment on 'Pinch current limitation effect in plasma focus'' [Appl. Phys. Lett. 94, 076101 (2009)

    International Nuclear Information System (INIS)

    Lee, S.; Saw, S. H.

    2009-01-01

    The main point of the comment [Appl. Phys. Lett. 94, 076101 (2009)] is that Eq. (2) and consequentially Eq. (3) of the commented paper [Appl. Phys. Lett. 92, 021503 (2008)] require correction. The alternative equation suggested in the comment is derived using Kirchhoff's voltage rule. The comment consider only the energy distribution in the inductive components and the resultant equation confirms a progressive lowering of the I pinch /I peak ratio as the static inductance L 0 is reduced, lowering from 0.87 to 0.31 as L 0 is reduced from 100 to 5 nH according to the revised formula corresponding to Eq. (3), compared to 0.63-0.25 according to Eq. (3). This progressive lowering of the ratio I pinch /I peak due to the inductive energy distribution is one of two factors responsible for the pinch current limitation. The other factor is the progressive reduction in the L-C interaction time compared to the current dip duration denoted by δ cap in Eq. (2). The comment does not deal with δ cap at all; hence, its conclusion based on inductive energy distribution only is not useful, since in the low L 0 region when pinch current limitation begins to manifest, δ cap becomes more and more the dominant factor. In any case, the results of the paper do not depend on Eqs. (2) and (3), which are used in the paper only for illustrative purposes

  20. Extraction of compositional and hydration information of sulfates from laser-induced plasma spectra recorded under Mars atmospheric conditions — Implications for ChemCam investigations on Curiosity rover

    International Nuclear Information System (INIS)

    Sobron, Pablo; Wang, Alian; Sobron, Francisco

    2012-01-01

    Given the volume of spectral data required for providing accurate compositional information and thereby insight in mineralogy and petrology from laser-induced breakdown spectroscopy (LIBS) measurements, fast data processing tools are a must. This is particularly true during the tactical operations of rover-based planetary exploration missions such as the Mars Science Laboratory rover, Curiosity, which will carry a remote LIBS spectrometer in its science payload. We have developed: an automated fast pre-processing sequence of algorithms for converting a series of LIBS spectra (typically 125) recorded from a single target into a reliable SNR-enhanced spectrum; a dedicated routine to quantify its spectral features; and a set of calibration curves using standard hydrous and multi-cation sulfates. These calibration curves allow deriving the elemental compositions and the degrees of hydration of various hydrous sulfates, one of the two major types of secondary minerals found on Mars. Our quantitative tools are built upon calibration-curve modeling, through the correlation of the elemental concentrations and the peak areas of the atomic emission lines observed in the LIBS spectra of standard samples. At present, we can derive the elemental concentrations of K, Na, Ca, Mg, Fe, Al, S, O, and H in sulfates, as well as the hydration degrees of Ca- and Mg-sulfates, from LIBS spectra obtained in both Earth atmosphere and Mars atmospheric conditions in a Planetary Environment and Analysis Chamber (PEACh). In addition, structural information can be potentially obtained for various Fe-sulfates. - Highlights: ► Routines for LIBS spectral data fast automated processing. ► Identification of elements and determination of the elemental composition. ► Calibration curves for sulfate samples in Earth and Mars atmospheric conditions. ► Fe curves probably related to the crystalline structure of Fe-sulfates. ► Extraction of degree of hydration in hydrous Mg-, Ca-, and Fe-sulfates.

  1. tavgU_2d_chm_Fx: MERRA Chem 2D IAU Diagnostics, Fluxes and Meteorology, Diurnal 1.25 x 1 degree V5.2.0 (MATUFXCHM) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUFXCHM or tavgU_3d_chm_Fx data product is the MERRA Data Assimilation System Chemistry 2-Dimensional chemistry that is time averaged, single-level, at reduced...

  2. Implementation of warm-cloud processes in a source-oriented WRF/Chem model to study the effect of aerosol mixing state on fog formation in the Central Valley of California

    Directory of Open Access Journals (Sweden)

    H.-H. Lee

    2016-07-01

    Full Text Available The source-oriented Weather Research and Forecasting chemistry model (SOWC was modified to include warm cloud processes and was applied to investigate how aerosol mixing states influence fog formation and optical properties in the atmosphere. SOWC tracks a 6-D chemical variable (X, Z, Y, size bins, source types, species through an explicit simulation of atmospheric chemistry and physics. A source-oriented cloud condensation nuclei module was implemented into the SOWC model to simulate warm clouds using the modified two-moment Purdue Lin microphysics scheme. The Goddard shortwave and long-wave radiation schemes were modified to interact with source-oriented aerosols and cloud droplets so that aerosol direct and indirect effects could be studied. The enhanced SOWC model was applied to study a fog event that occurred on 17 January 2011, in the Central Valley of California. Tule fog occurred because an atmospheric river effectively advected high moisture into the Central Valley and nighttime drainage flow brought cold air from mountains into the valley. The SOWC model produced reasonable liquid water path, spatial distribution and duration of fog events. The inclusion of aerosol–radiation interaction only slightly modified simulation results since cloud optical thickness dominated the radiation budget in fog events. The source-oriented mixture representation of particles reduced cloud droplet number relative to the internal mixture approach that artificially coats hydrophobic particles with hygroscopic components. The fraction of aerosols activating into cloud condensation nuclei (CCN at a supersaturation of 0.5 % in the Central Valley decreased from 94 % in the internal mixture model to 80 % in the source-oriented model. This increased surface energy flux by 3–5 W m−2 and surface temperature by as much as 0.25 K in the daytime.

  3. tavg3_3d_chm_Fe: MERRA Chem 3D IAU, Precip Mass Flux, Time average 3-hourly 1.25 x 1 degree V5.2.0 (MAT3FECHM) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3FECHM or tavg3_3d_chm_Fe data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layers edges that is time averaged, 3D model...

  4. MERRA Chem 3D IAU C-Grid Wind and Mass Flux, Time Average 3-Hourly (eta coord, 2/3x1/2L72) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3NVCHM or tavg3_3d_chm_Nv data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layers that is time averaged, 3D model...

  5. MERRA Chem 3D IAU C-Grid Edge Mass Flux, Time Average 3-Hourly (eta coord, 2/3x1/2L73) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3NECHM or tavg3_3d_chm_Ne data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layer Edges that is time averaged, 3D model...

  6. tavg3_3d_chm_Fv: MERRA Chem 3D IAU States Cloud Precip, Time average 3-hourly 1.25 x 1.25 degree V5.2.0 (MAT3FVCHM) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3FVCHM or tavg3_3d_chm_Fv data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layers file that is time averaged, 3D model...

  7. tavg3_2d_chm_Fx: MERRA Chem 2D IAU Diagnostics, Fluxes and Meteorology, Time Average 3-hourly 1.25 x 1 degree V5.2.0 (MAT3FXCHM) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT3FXCHM or tavg3_3d_chm_Fx data product is the MERRA Data Assimilation System Chemistry 2-Dimensional chemistry that is time averaged, single-level, at reduced...

  8. Cover Picture: Metal‐Free Dehydration of Glucose to 5‐(Hydroxymethyl)furfural in Ionic Liquids with Boric Acid as a Promoter (Chem. Eur. J. 5/2011)

    DEFF Research Database (Denmark)

    Ståhlberg, Tim Johannes Bjarki; Rodriguez, Sergio; Fristrup, Peter

    2011-01-01

    Boric acid promotes the dehydration of glucose to 5-(hydroxy)methylfurfural in ionic liquids. Computational analyses by DFT calculations show a significant decrease in energy for the isomerization of glucose to fructose when the sugars are bound to boric acid and isotopic labeling NMR studies con...

  9. Air quality real-time forecast before and during the G-20 Summit 2016 in Hangzhou with the WRF-CMAQ and WRF/Chem systems: Evaluation and Emission Reduction Effects

    Science.gov (United States)

    The 2016 G-20 Hangzhou summit, the eleventh annual meeting of the G-20 heads of government, will be held during September 3-5, 2016 in Hangzhou, China. For a successful summit, it is important to ensure good air quality. To achieve this goal, governments of Hangzhou and its surr...

  10. Comment on “Stationary self-focusing of Gaussian laser beam in relativistic thermal quantum plasma” [Phys. Plasmas 20, 072703 (2013)

    International Nuclear Information System (INIS)

    Habibi, M.; Ghamari, F.

    2014-01-01

    Patil and Takale in their recent article [Phys. Plasmas 20, 072703 (2013)], by evaluating the quantum dielectric response in thermal quantum plasma, have modeled the relativistic self-focusing of Gaussian laser beam in a plasma. We have found that there are some important shortcomings and fundamental mistakes in Patil and Takale [Phys. Plasmas 20, 072703 (2013)] that we give a brief description about them and refer readers to important misconception about the use of the Fermi temperature in quantum plasmas, appearing in Patil and Takale [Phys. Plasmas 20, 072703 (2013)

  11. On the use temperature parameterized rate coefficients in the estimation of non-equilibrium reaction rates

    Science.gov (United States)

    Shizgal, Bernie D.; Chikhaoui, Aziz

    2006-06-01

    The present paper considers a detailed analysis of the nonequilibrium effects for a model reactive system with the Chapman-Eskog (CE) solution of the Boltzmann equation as well as an explicit time dependent solution. The elastic cross sections employed are a hard sphere cross section and the Maxwell molecule cross section. Reactive cross sections which model reactions with and without activation energy are used. A detailed comparison is carried out with these solutions of the Boltzmann equation and the approximation introduced by Cukrowski and coworkers [J. Chem. Phys. 97 (1992) 9086; Chem. Phys. 89 (1992) 159; Physica A 188 (1992) 344; Chem. Phys. Lett. A 297 (1998) 402; Physica A 275 (2000) 134; Chem. Phys. Lett. 341 (2001) 585; Acta Phys. Polonica B 334 (2003) 3607.] based on the temperature of the reactive particles. We show that the Cukrowski approximation has limited applicability for the large class of reactive systems studied in this paper. The explicit time dependent solutions of the Boltzmann equation demonstrate that the CE approach is valid only for very slow reactions for which the corrections to the equilibrium rate coefficient are very small.

  12. Response to "Comment on `Solitonic and chaotic behaviors for the nonlinear dust-acoustic waves in a magnetized dusty plasma'" [Phys. Plasmas 24, 094701 (2017)

    Science.gov (United States)

    Zhen, Hui-Ling; Tian, Bo; Xie, Xi-Yang; Wu, Xiao-Yu; Wen, Xiao-Yong

    2018-02-01

    On our previous construction [H. L. Zhen et al., Phys. Plasmas 23, 052301 (2016)] of the soliton solutions of a model describing the dynamics of the dust particles in a weakly ionized, collisional dusty plasma comprised of the negatively charged cold dust particles, hot ions, hot electrons, and stationary neutrals in the presence of an external static magnetic field, Ali et al. [Phys. Plasmas 24, 094701 (2017)] have commented that there exists a different form of Eq. (4) from that shown in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] and that certain interesting phenomena with the dust neutral collision frequency ν0>0 are ignored in Zhen et al. [Phys. Plasmas 23, 052301 (2016)]. In this Reply, according to the transformation given by the Ali et al. [Phys. Plasmas 24, 094701 (2017)] comment, we present some one-, two-, and N-soliton solutions which have not been obtained in the Ali et al. [Phys. Plasmas 24, 094701 (2017)] comment. We point out that our previous solutions in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] are still valid because of the similarity between the two dispersion relations of previous solutions in Zhen et al. [Phys. Plasmas 23, 052301 (2016)] and the solutions presented in this Reply. Based on our soliton solutions in this Reply, it is found that the soliton amplitude is inversely related to Zd and B0, but positively related to md and α, where α refers to the coefficient of the nonlinear term, Zd and md are the charge number and mass of a dust particle, respectively, B0 represents the strength of the external static magnetic field. We also find that the two solitons are always in parallel during the propagation.

  13. Comment on 'Relation between space charge limited current and power loss in open drift tubes' [Phys. Plasmas 13, 073101 (2006)

    International Nuclear Information System (INIS)

    Swanekamp, S. B.; Schumer, J. W.

    2007-01-01

    In Phys Plasmas 13, 073101 (2006), the drop in the space-charge-limited (SCL) current for a beam injected into a space with an open boundary is analyzed with an electromagnetic particle-in-cell code. The authors explained the power loss observed at the open boundary as the loss of electromagnetic radiation created from the deceleration of electrons in the gap, and they developed an effective voltage theory to predict the drop in the SCL current observed in the simulations. In this Comment, we show that, provided the current remains below the SCL value, the electric and magnetic fields are constant in time so that power loss from the open boundary is a dc phenomenon with no rf power leaving through the boundary. We show that the electric and magnetic fields are static in time and static fields DO NOT RADIATE. Instead, the electron beam charges the collector plate, which causes a real electrostatic electric field to develop. The electron energy loss is not due to radiation but rather to the work done by this electrostatic field on the electrons as they move across the gap. This is precisely the energy dissipated in the matched resistance across the open boundary, which is a consequence of the boundary condition. Furthermore, since a real electrostatic potential develops, the voltage drop is real and there is no need to call the voltage drop an effective voltage

  14. Comment on “Diffusion of n-type dopants in germanium” [Appl. Phys. Rev. 1, 011301 (2014)

    International Nuclear Information System (INIS)

    Cowern, N. E. B.; Simdyankin, S.; Goss, J. P.; Napolitani, E.; De Salvador, D.; Bruno, E.; Mirabella, S.; Ahn, C.; Bennett, N. S.

    2015-01-01

    The authors of the above paper call into question recent evidence on the properties of self-interstitials, I, in Ge [Cowern et al., Phys. Rev. Lett. 110, 155501 (2013)]. We show that this judgment stems from invalid model assumptions during analysis of data on B marker-layer diffusion during proton irradiation, and that a corrected analysis fully supports the reported evidence. As previously stated, I-mediated self-diffusion in Ge exhibits two distinct regimes of temperature, T: high-T, dominated by amorphous-like mono-interstitial clusters—i-morphs—with self-diffusion entropy ≈30 k, and low-T, where transport is dominated by simple self-interstitials. In a transitional range centered on 475 °C both mechanisms contribute. The experimental I migration energy of 1.84 ± 0.26 eV reported by the Münster group based on measurements of self-diffusion during irradiation at 550 °C < T < 680 °C further establishes our proposed i-morph mechanism

  15. Fixed node diffusion Monte Carlo using a genetic algorithm: a study of the CO-(4)He(N) complex, N = 1…10.

    Science.gov (United States)

    Ramilowski, Jordan A; Farrelly, David

    2012-06-14

    The diffusion Monte Carlo (DMC) method is a widely used algorithm for computing both ground and excited states of many-particle systems; for states without nodes the algorithm is numerically exact. In the presence of nodes approximations must be introduced, for example, the fixed-node approximation. Recently we have developed a genetic algorithm (GA) based approach which allows the computation of nodal surfaces on-the-fly [Ramilowski and Farrelly, Phys. Chem. Chem. Phys., 2010, 12, 12450]. Here GA-DMC is applied to the computation of rovibrational states of CO-(4)He(N) complexes with N≤ 10. These complexes have been the subject of recent high resolution microwave and millimeter-wave studies which traced the onset of microscopic superfluidity in a doped (4)He droplet, one atom at a time, up to N = 10 [Surin et al., Phys. Rev. Lett., 2008, 101, 233401; Raston et al., Phys. Chem. Chem. Phys., 2010, 12, 8260]. The frequencies of the a-type (microwave) series, which correlate with end-over-end rotation in the CO-(4)He dimer, decrease from N = 1 to 3 and then smoothly increase. This signifies the transition from a molecular complex to a quantum solvated system. The frequencies of the b-type (millimeter-wave) series, which evolves from free rotation of the rigid CO molecule, initially increase from N = 0 to N∼ 6 before starting to decrease with increasing N. An interesting feature of the b-type series, originally observed in the high resolution infra-red (IR) experiments of Tang and McKellar [J. Chem. Phys., 2003, 119, 754] is that, for N = 7, two lines are observed. The GA-DMC algorithm is found to be in good agreement with experimental results and possibly detects the small (∼0.7 cm(-1)) splitting in the b-series line at N = 7. Advantages and disadvantages of GA-DMC are discussed.

  16. Fulltext PDF

    Indian Academy of Sciences (India)

    Unknown

    2003-04-24

    Apr 24, 2003 ... maintained to 65°C. Into this, dropwise injection of Na2S solution led to ..... Chestnoy N, Harris T D, Hull R and Brus L E 1986 J. Phys. Chem. 90 3393 ... Wang Y, Suna A, Meltugh J, Hilniski E F, Lucas P A and John- son R D ...

  17. CALCULATION OF THE PROTON-TRANSFER RATE USING DENSITY-MATRIX EVOLUTION AND MOLECULAR-DYNAMICS SIMULATIONS - INCLUSION OF THE PROTON EXCITED-STATES

    NARCIS (Netherlands)

    MAVRI, J; BERENDSEN, HJC

    1995-01-01

    The methodology for treatment of proton transfer processes by density matrix evolution (DME) with inclusion of many excited states is presented. The DME method (Berendsen, H. J. C.; Mavri, J. J. Phys. Chem. 1993, 97, 13464) that simulates the dynamics of quantum systems embedded in a classical

  18. International symposium on 'applications of zeolites in heterogeneous catalysis'

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    The International Symposium on applications of zeolites in heterogeneous catalysis, organized by the Hungarian Chemical Society (Szeged, Hung. 9/11-14/78), included 48 papers, which were published in the Vertical Bar3Vertical BarActa Phys. Chem. (Szeged) 24.

  19. Compressibility and specific heats of heavier condensed rare gases near the liquid-vapour critical point

    International Nuclear Information System (INIS)

    March, N.H.

    2003-08-01

    Sarkisov (J. Chem. Phys. 119, 373, 2003) has recently discussed the structural behaviour of a simple fluid near the liquid-vapour critical point. His work, already compared with computer simulation studies, is here brought into direct contact for the heavier condensed rare gases Ar, Kr and Xe with (a) experiment and (b) earlier theoretical investigations. Directions for future studies then emerge. (author)

  20. On coherent-state representations of quantum mechanics: Wave mechanics in phase space

    DEFF Research Database (Denmark)

    Møller, Klaus Braagaard; Jørgensen, Thomas Godsk; Torres-Vega, Gabino

    1997-01-01

    In this article we argue that the state-vector phase-space representation recently proposed by Torres-Vega and co-workers [introduced in J. Chem. Phys. 98, 3103 (1993)] coincides with the totality of coherent-state representations for the Heisenberg-Weyl group. This fact leads to ambiguities when...

  1. Communication: The absolute shielding scales of oxygen and sulfur revisited

    Energy Technology Data Exchange (ETDEWEB)

    Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Ruud, Kenneth, E-mail: kenneth.ruud@uit.no [Centre for Theoretical and Computational Chemistry, University of Tromsø — The Arctic University of Norway, N-9037 Tromsø (Norway); Gauss, Jürgen [Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz (Germany)

    2015-03-07

    We present an updated semi-experimental absolute shielding scale for the {sup 17}O and {sup 33}S nuclei. These new shielding scales are based on accurate rotational microwave data for the spin–rotation constants of H{sub 2}{sup 17}O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)], C{sup 17}O [Cazzoli et al., Phys. Chem. Chem. Phys. 4, 3575 (2002)], and H{sub 2}{sup 33}S [Helgaker et al., J. Chem. Phys. 139, 244308 (2013)] corrected both for vibrational and temperature effects estimated at the CCSD(T) level of theory as well as for the relativistic corrections to the relation between the spin–rotation constant and the absolute shielding constant. Our best estimate for the oxygen shielding constants of H{sub 2}{sup 17}O is 328.4(3) ppm and for C{sup 17}O −59.05(59) ppm. The relativistic correction for the sulfur shielding of H{sub 2}{sup 33}S amounts to 3.3%, and the new sulfur shielding constant for this molecule is 742.9(4.6) ppm.

  2. Studies of E-Beam Pumped Molecular Lasers

    Science.gov (United States)

    1975-01-31

    positive and Vegard- Kaplan systems remains to be demonstrated. Our survey also indicated the promise of energy transfer from xenon to oxygen containing...Murray, and C. K. Rhodes, Appl. Phys. Lett. 25, 730 (1974). PMR74b H. T. Powell, J. R. Murray, and C. K. Rhodes, Paper MA2 4th Conf. on Chem

  3. Fluid-crystal coexistence for proteins and inorganic nanocolloids : Dependence on ionic strength

    NARCIS (Netherlands)

    Prinsen, P.; Odijk, T.

    2006-01-01

    We investigate theoretically the fluid-crystal coexistence of solutions of globular charged nanoparticles such as proteins and inorganic colloids. The thermodynamic properties of the fluid phase are computed via the optimized Baxter model P. Prinsen and T. Odijk [J. Chem. Phys. 121, 6525 (2004)].

  4. Novel Functional Extended Solids at Extreme Conditions

    Science.gov (United States)

    2013-02-01

    15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON a...ray Evidences J. Chem. Phys. 134, 044519 (2011). 19. Magnus J. Lipp, Jae-Hyun Klepeis, Bruce Baer, Hyunchae Cynn, William J. Evans, Valentin Iota

  5. Aerosol measurements over South Africa using LIDAR, Satellite and Sun Photometer

    CSIR Research Space (South Africa)

    Sivakumar, V

    2010-05-01

    Full Text Available . Sivakumar, M. Tesfaye, W. Alemu, D. Moema, A. Sharma, C. Bollig and G. Mengistu, South African J. Science (2010), in press. 4. W. Chu, M. McCormick, J. Lenoble, J. Geophys. Res. 94 (1989) 8339. 5. L. Thomason, L. Poole and C. Randall, Atmos. Chem. Phys. 7...

  6. The Rovibronic Spectra of the Cyclopentadienyl Radical

    Science.gov (United States)

    Sharma, Ketan; Miller, Terry A.; Stanton, John F.; Nesbitt, David

    2017-06-01

    Cyclopentadienyl (Cp) radical has been subject to numerous studies for the greater part of half a century. Experimental work has involved photo-electron spectroscopy, laser induced fluorescence excitation and emission, infrared absorption spectroscopy, and recently rotationally resolved spectra in the CH stretch region taken at JILA. Even more theoretical works appear in the literature, but substantial advances in computation have occurred since their completion. Cp's highly symmetric (D_{5h}) structure and doubly degenerate electronic ground (˜{X}^2E_1^{''}), which is subject to linear Jahn-Teller distortion, have been a great motivation for work on it. We have commenced new computational work to obtain a broad understanding of the electronic, vibrational, and rotational, i.e. rovibronic, structure of the Cp radical as revealed by its spectra, with particular emphasis on the new infrared spectra. The goal is to guide experiments and their analyses and reconcile results from spectroscopy and quantum chemistry calculations. T. Ichino, et al. J. Chem. Phys. 129, 084310 (2008) L. Yu, S. C. Foster, J. M. Williamson, M. C. Heaven and T. A. Miller J. Phys. Chem. 92, 4263 (1988) B. E. Applegate, A. J. Bezant and T. A. Miller J. Chem. Phys 114, 4869 (2001) D. Leicht, M. Kaufmann, G. Schwaab, and M. Havenith J. Chem. Phys. 145, 7 (2016), 074304.

  7. Autoionization structure of nitric oxide (NO) at the first ionization limit

    International Nuclear Information System (INIS)

    Miescher, E.; Lee, Y.T.; California Univ., Berkeley; Guertler, P.

    1977-12-01

    A new and more detailed interpretation is given to the fine structure in the photoionization curve of cold NO observed by Ng, Mahan and Lee (J. Chem. Phys. 65 (1976) 1975). Resonances are assigned to autoionizing np and nd delta Rydberg levels which give prominent diffuse absorption bands in a spectrum recorded with the synchrotron radiation continuum. Δv [de

  8. Fulltext PDF

    Indian Academy of Sciences (India)

    [7] Mahdhi H, Ben Ayadi Z, Gauffier J L, Djessas K and Alaya S. 2015 Opt. Mater. ... [23] Wu D W, Yang M, Huang Z B, Yin G F, Liao X M, Kang Y. Q, Chen X F and ... [42] Lee P A, Said G, Davis R and Lim T H 1969 J. Phys. Chem. Solids 30 ...

  9. Theoretical Studies of Solid Nitromethane

    National Research Council Canada - National Science Library

    Sorescu, Dan

    2001-01-01

    .... The intermolecular potential used is of the Buckingham 6-exp form plus charge-charge Coulombic interactions and has been previously developed by us (Sorescu, D. C.; Rice, B. M.; Thompson, D. L. J: Phys. Chem. 1997, BlOl, 798...

  10. Validity of the Rosenfeld relationship: A comparative study of the ...

    Indian Academy of Sciences (India)

    ATREYEE BANERJEE

    we find that the NTW model has mixed characteristics of simple liquids and ionic melts. Our study further ... and the value of the Rosenfeld exponents are differ- ent from that found for ..... Lennard-Jones chains J. Chem. Phys. 129 164904. 4.

  11. Synthesis, photophysical and preliminary investigation of the dye-sensitized solar cells properties of functionalized anthracenyl-based bipyridyl and phenanthrolyl Ru(II) complexes

    CSIR Research Space (South Africa)

    Adeloye, AO

    2013-01-01

    Full Text Available .Ali S, Arta S, Sina H, Siguang C, Pierre G P and Sylvie M 2008 J. New Mat. Electrochem. Systems 11 281 39.Ruhle S, Greenshtein M, Chen S G, Merson A, Pizen H, Sukenik S, Cahen D and Zaban A 2005 J. Phys. Chem. B 109 18907 40.Hoshikawa T, Kikuchi R...

  12. Retraction of “Accurate Prediction of Essential Fundamental Properties for Semiconductors Used in Solar-Energy Conversion Devices from Range-Separated Hybrid Density Functional Theory”

    KAUST Repository

    Harb, Moussab

    2016-03-08

    The author retracts this article due to similarities with a previously published article by Le Bahers, T.; Rerat, M.; Sautet, ́ P. Semiconductors Used in Photovoltaic and Photocatalytic Devices: Assessing Fundamental Properties from DFT. J. Phys. Chem. C 2014, 118 (12), 5997−6008 (DOI: 10.1021/jp409724c).

  13. Multifunctional Ultra-High Vacuum Apparatus for Studies of the Interactions of Chemical Warfare Agents on Complex Surfaces

    Science.gov (United States)

    2014-01-02

    How- ever, the complete absence of trace amounts of CWAs from the system is never guaranteed. Therefore, prior to venting the chamber and opening a...Gay, A. J. McFarlan, and B. A. Morrow, “Trimethyl phosphite ad- sorbed on silica - An NMR and infrared study,” J. Phys. Chem. 95(3), 1360–1368 (1991

  14. Synthesis of γ-Al2O3 nanowires through a boehmite precursor route

    Indian Academy of Sciences (India)

    has applications in absorbent, catalyst carrier and reinforce- ment of ceramic .... nia into the transparent solution, Al(OH)3 with colloidal form generates .... 99 1823. Zhou J, Deng S Z, Chen J, She J C and Xu N S 2002 Chem. Phys. Lett. 365 505.

  15. Theoretical Criteria for Scattering Dark States in Nanostructured Particles

    Science.gov (United States)

    2014-01-01

    64, 023805. (39) Suh, W.; Wang, Z.; Fan, S. IEEE J. Quantum Electron. 2004, 40, 1511–1518. (40) Smith, D. D.; Chang, H.; Fuller, K. A.; Rosenberger...Mukherjee, S.; Mirin, N. A.; Levit , S. D.; Nordlander, P.; Halas, N. J. J. Phys. Chem. C 2010, 114, 7378–7383. 16 (60) Wang, M.; Cao, M.; Chen, X.; Gu

  16. Optimization of Broadband Optical Response of Multilayer Nanospheres

    Science.gov (United States)

    2012-07-27

    D. Levit , P. Nordlander, and N. J. Halas, “Nanosphere-in-a-nanoshell: A simple nanomatryushka,” J. Phys. Chem. C 114, 7378–7383 (2010). #169722...metal nanoparticles coated with a dye j-aggregate monolayer,” Quantum Electron. 40, 246–248 (2010). 1. Introduction Nanoparticles with strong optical

  17. Jahn-Teller effect in van der Waals complexes; Ar-C6H6 + and Ar-C6D6 +.

    NARCIS (Netherlands)

    Avoird, A. van der; Lotrich, VF

    2004-01-01

    The two asymptotically degenerate potential energy surfaces of argon interacting with the X (2)E(1g) ground state benzene(+) cation were calculated ab initio from the interaction energy of the neutral Ar-benzene complex given by Koch et al. [J. Chem. Phys. 111, 198 (1999)] and the difference of the

  18. Charge-resonance excitations in symmetric molecules - Comparison of linear response DFT with CC3 for the excited states of a model dimer

    DEFF Research Database (Denmark)

    Kuhlman, Thomas Scheby; Mikkelsen, Kurt V.; Møller, Klaus Braagaard

    2009-01-01

    to a reference CC3 calculation revealing a better description of the excited states by CAM-B3LYP than that of B3LYP. The Λ parameter introduced by Peach et al. [M.J.G. Peach, P. Benfield, T. Helgaker, D.J. Tozer, J. Chem. Phys. 128 (2008) 044118] does not always reveal the problematic charge-resonance states...

  19. Semiconductor Deposition and Etching Interactions of Laser-Generated Translationally Hot Atoms and Radicals

    Science.gov (United States)

    1991-05-01

    fluorescence," J. Chem. Phys. 86, 6731 (1987). J. E. Smedley , H. K. Haugen and S. R. Leone, "Collision-induced dissociation of laser- excited Br 2 [B3Fl(Ou... Robert J. Levis, postdoc, presently Assistant Professor of Chemistry, Wayne State University. Lisa M. Cousins, graduate student, Ph.D. 1989, presently

  20. On the structure of Si(100) surface

    DEFF Research Database (Denmark)

    Back, Seoin; Schmidt, Johan Albrecht; Ji, Hyunjun

    2013-01-01

    dimers are still shown to be lower in energy than the buckled dimers when using the CASPT2 method on the DHDF optimized geometries, consistent with the previous results using B3LYP geometries [Y. Jung, Y. Shao, M. S. Gordon, D. J. Doren, and M. Head-Gordon, J. Chem. Phys. 119, 10917 (2003...

  1. Photodissociation of OCS: Deviations between theory and experiment, and the importance of higher order correlation effects

    DEFF Research Database (Denmark)

    Schmidt, Johan Albrecht; Olsen, Jógvan Magnus Haugaard

    2014-01-01

    The photodissociation of carbonyl sulfide (OCS) was investigated theoretically in a series of studies by Schmidt and co-workers. Initial studies [J. A. Schmidt, M. S. Johnson, G. C. McBane, and R. Schinke, J. Chem. Phys.136, 131101 (2012);J. A. Schmidt, M. S. Johnson, G. C. McBane, and R. Schinke...

  2. Temperature dependence of Self-diffusion coefficient (SDC) of liquid ...

    African Journals Online (AJOL)

    PROF HORSFALL

    2018-04-09

    Apr 9, 2018 ... inverse square relationship between the natural logarithm of self-diffusion ... using the Equilibrium Molecular Dynamics (MD) and ..... Density, and Viscosity of Liquid Aluminum and. Iron. J. Phys. Chem. Ref. Data 35 ... Atomic Diffusion in Condensed Matter. Nature. 381: 137. Einstein, A (1905). Annalen der ...

  3. Electrochemical behaviour of superhydrophobic coating fabricated ...

    Indian Academy of Sciences (India)

    ties make it useful in household and industrial fields such as marine, automotive and ... are its simplicity, more cost effectiveness and less complex condition to .... Li M, Zhai J, Liu H, Song Y, Jiang L and Zhu D 2003 J. Phys. Chem. B 107 9954.

  4. Neutron Scattering for Materials Science. Materials Research Society Symposium Proceedings, Volume 166

    Science.gov (United States)

    1990-01-01

    technique - with experimentally produced quartz and calcite textures and the texture of a fluor-apatite sample from a dinosaur bone. Figure 1. Schematic...Lett. 58, 2718 (1987). 6. J. W. Cahn, J. Chem. Phys. 42, 93 (1965). 7. W. Haller, in Solid Phase Biochemistry - Analytical and Chemical Aspects

  5. Non-Self-Maintained Discharge Application for Fuel Activation

    Science.gov (United States)

    2010-09-21

    references have been used: Eliasson B., Kogelschatz U., J. de Chimie Physique. 1986. V.83. P.279. Maetzing H. Chemical Kinetics of Flue Gas Cleaning by...Person J.C., Ham D.O. Radiat. Phys. Chem. 1988. V. 31. N.1-3. P. Eliasson B., Kogelschatz U., J. de Chimie Physique. 1986. V.83. P.279. Mukkavilli

  6. On the universality of the long-/short-range separation in multiconfigurational density-functional theory. II. Investigating f0 actinide species

    DEFF Research Database (Denmark)

    Fromager, Emmanuel; Réal, Florent; Wåhlin, Pernilla

    2009-01-01

    In a previous paper [Fromager , J. Chem. Phys. 126, 074111 (2007)], some of the authors proposed a recipe for choosing the optimal value of the mu parameter that controls the long-range/short-range separation of the two-electron interaction in hybrid multiconfigurational self-consistent field sho...

  7. Global bending quantum number and the absence of monodromy in the HCN-CNH molecule

    NARCIS (Netherlands)

    Efstathiou, K; Joyeux, M; Sadovskií, D. A.

    We introduce and analyze a model system based on a deformation of a spherical pendulum that can be used to reproduce large amplitude bending vibrations of flexible triatomic molecules with two stable linear equilibria. On the basis of our model and the recent vibrational potential [ J. Chem. Phys.

  8. Single and Double Infrared Transitions in Rapid Vapor Deposited Parahydrogen Solids: Application to Sample Thickness Determination and Quantitative Infrared Absorption Spectroscopy

    National Research Council Canada - National Science Library

    Tam, Simon

    2001-01-01

    ...) solid from its infrared (IR) absorption spectrum. Millimeters-thick pH2 solids of exceptional optical clarity can be produced by the rapid vapor deposition method M.E. Fajardo and S. Tam, J. Chem. Phys. 108, 4237 (1998...

  9. Modelling the Energetics of Encapsulation of Atoms and Atomic ...

    Indian Academy of Sciences (India)

    user

    2015-07-04

    Jul 4, 2015 ... 3. Encapsulation into carbon nanotubes. Gases. Biomolecules like proteins and DNA. Assemblies of molecules. Drug molecules. Lulevich et al. Nano Lett. 11, 1171 (2011). Quinonero et al. J. Phys. Chem. C 116, 21083 (2012). Zhang et al. ACS Nano 6, 8674 (2012). Chaban et al. ACS Nano 5, 5647 (2011) ...

  10. Structural study of nanosized yttrium-doped CaMnO3 perovskites

    Indian Academy of Sciences (India)

    Administrator

    Mater. 10 2461. Rodriguez-Carvajal J 1990 Collected abstract of powder di- ffraction meeting, Toulouse, p. 127. Shannon R D 1976 Acta Cryst. A32 751. Woodward P M, Vogt T, Cox D E, Arulraj A, Rao C N R,. Karen P and Cheetham A K 1998 Chem. Mater. 10 3652. Wunderlich F, Leisegang T and Weissbach T 2010 Phys.

  11. Evolution of Trace Gases and Particles Emitted by a Chaparral Fire in California

    Science.gov (United States)

    2012-02-07

    measurements in BB plumes and concluded that O3 formation is ubiquitous in tropical BB plumes, but O3 formation or destruction can oc- cur in extratropical BB...the Aventech AIMMS20AQ air- borne probe for turbulence measurements during the Convective Storm Initiation Project, Atmos. Chem. Phys., 8, 5449–5463

  12. Study of hydrogen-molecule guests in type II clathrate hydrates using a force-matched potential model parameterised from ab initio molecular dynamics

    Science.gov (United States)

    Burnham, Christian J.; Futera, Zdenek; English, Niall J.

    2018-03-01

    The force-matching method has been applied to parameterise an empirical potential model for water-water and water-hydrogen intermolecular interactions for use in clathrate-hydrate simulations containing hydrogen guest molecules. The underlying reference simulations constituted ab initio molecular dynamics (AIMD) of clathrate hydrates with various occupations of hydrogen-molecule guests. It is shown that the resultant model is able to reproduce AIMD-derived free-energy curves for the movement of a tagged hydrogen molecule between the water cages that make up the clathrate, thus giving us confidence in the model. Furthermore, with the aid of an umbrella-sampling algorithm, we calculate barrier heights for the force-matched model, yielding the free-energy barrier for a tagged molecule to move between cages. The barrier heights are reasonably large, being on the order of 30 kJ/mol, and are consistent with our previous studies with empirical models [C. J. Burnham and N. J. English, J. Phys. Chem. C 120, 16561 (2016) and C. J. Burnham et al., Phys. Chem. Chem. Phys. 19, 717 (2017)]. Our results are in opposition to the literature, which claims that this system may have very low barrier heights. We also compare results to that using the more ad hoc empirical model of Alavi et al. [J. Chem. Phys. 123, 024507 (2005)] and find that this model does very well when judged against the force-matched and ab initio simulation data.

  13. State-resolved Thermal/Hyperthermal Dynamics of Atmospheric Species

    Science.gov (United States)

    2015-06-23

    M. Zolot, W. W. Harper , B. G. Perkins, P. J. Dagdigian, and D. J. Nesbitt, J. Chem. Phys. 125 (2) (2006). 4 B. G. Perkins and D. J. Nesbitt, Proc...Quantum Dots to Biomolecules,” Department of Chemistry and Biochemistry , Florida State University, Tallahassee, FL, March 18, 2011. DISTRIBUTION A

  14. Circle Maps and the Devil's Staircase in a Chemical Oscillator

    DEFF Research Database (Denmark)

    Brøns, Morten; Gross, P.; Bar-Eli, K.

    1996-01-01

    We explain numerical results on a periodically perturbed Oregonator by Markman and Bar-Eli (J. Phys. Chem. 98 12248 (1994)). If the dynamics of the system is governed by a family of diffeomorphisms of a circle with a Devil's staircase one will expect the observed behavior, i.e. (1) Only periodic...

  15. TREATMENT OF NONADIABATIC TRANSITIONS BY DENSITY-MATRIX EVOLUTION AND MOLECULAR-DYNAMICS SIMULATIONS

    NARCIS (Netherlands)

    MAVRI, J; BERENDSEN, HJC

    1994-01-01

    A density matrix evolution (DME) method (H.J.C. Berendsen and J. Mavri, J. Phys. Chem., 97 (1993) 13469) to simulate the dynamics of quantum systems embedded in a classical environment is presented. The DME method allows treatment of nonadiabatic transitions. As numerical examples the collinear

  16. Development of Ultrafast Indirect Flash Heating Methods for RDX

    Science.gov (United States)

    2014-02-01

    8 1 1. Introduction The mission of the Multiscale Response of Energetic Materials program is to establish...vinyl nitrate ) Films. J. Phys. Chem. A 2004, 108 (43), 9342–9347. 11 12. Gottfried, J. L.; de Lucia, F. C., Jr.; Piraino, S. M. Ultrafast Laser

  17. The Search for New High-Energy-Density Materials

    Science.gov (United States)

    2014-01-01

    Evolution of the superhalogen properties in PtCln clusters“, J. Chem. Phys. (in press). Behera, S. and Jena, P.: “Stability and Spectroscopic Properties...Society, Cocoa Beach, FL, February 21-25, 2010 US-Egypt Advanced Studies Institute (ASI) on “Nanomaterials and Nanocatalysis for Energy

  18. Recent Developments in the Photophysics of Single-Walled Carbon Nanotubes for Their Use as Active and Passive Material Elements in Thin Film Photovoltaics

    Science.gov (United States)

    2013-01-01

    tube was estimated to be a few percent using the corrected photon count rate from the imaging camera , the exposure time, and an absorption cross...16 F. Schöppler, C. Mann, T. C. Hain, F. M. Neubauer , G. Privitera, F. Bonaccorso, D. Chu, A. C. Ferrari and T. Hertel, J. Phys. Chem. C, 2011, 115

  19. Synthesis of crosslinked poly(styrene-co-divinylbenzene-co ...

    Indian Academy of Sciences (India)

    Administrator

    methacrylate) nanoparticles by emulsion polymerization: Tuning the particle size and surface .... (2 g, 8 mmol) was dissolved in 5 ml of water and injected. 10 min after the .... emulsion polymerization system, the probability of mono- mer swollen micelle ..... Hiltner P A, Papir Y S and Krieger I M 1971 J. Phys. Chem. 75. 1881.

  20. Spray and Combustion of Gelled Hypergolic Propellants for Future Rocket and Missile Engines

    Science.gov (United States)

    2014-08-13

    Park City, Utah, May 2013. [28]. L. S. Rothman, D. Jacquemart, A. Barbe, D. Chris Benner, M. Birk, L. R. Brown, M. R. Carleer, J. C. Chackerian, K...2371. [81]. J. Higgins , X. Zhou, R. Liu, T. T. S. Huang, “Theoretical Study of Thermal Decomposition Mechanism of Oxalic Acid”, J. Phys. Chem. A

  1. Smoothed particle hydrodynamics model for phase separating fluid mixtures. I. General equations

    NARCIS (Netherlands)

    Thieulot, C; Janssen, LPBM; Espanol, P

    We present a thermodynamically consistent discrete fluid particle model for the simulation of a recently proposed set of hydrodynamic equations for a phase separating van der Waals fluid mixture [P. Espanol and C.A.P. Thieulot, J. Chem. Phys. 118, 9109 (2003)]. The discrete model is formulated by

  2. Modifier constraints in alkali ultraphosphate glasses

    DEFF Research Database (Denmark)

    Rodrigues, B.P.; Mauro, J.C.; Yue, Yuanzheng

    2014-01-01

    In applying the recently introduced concept of cationic constraint strength [J. Chem. Phys. 140, 214501 (2014)] to bond constraint theory (BCT) of binary phosphate glasses in the ultraphosphate region of xR2O-(1-x)P2O5 (with x ≤ 0.5 and R = {Li, Na, Cs}), we demonstrate that a fundamental limitat...

  3. Heats of Vaporization of Room Temperature Ionic Liquids by Tunable Vacuum Ultraviolet Photoionization (Preprint)

    Science.gov (United States)

    2009-08-31

    A.; deyko, A.; Lovelock , K. R. J.; Licence, P.; Jones, R. G. J. Phys. Chem. B 2008, 112, 11734. (19) Armstrong, J. P.; Hurst, C.; Jones, R. G...Licence, P.; Lovelock , K. R. J.; Satterly, C. J.; Villar-Garcia, I. J. PCCP 2007, 9, 982. (20) Gross, J. H. J. Am. Soc. Mass Spectrom. 2008, 19, 1347

  4. Adsorption of Lithium on Finite Graphitic Clusters

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Cabria, I.; Lopez, M.J.

    2009-01-01

    The apparent discrepancies between density functional (DFT) and Moller-Plesset (MP2) calculations for the interaction of lithium with graphene recently pointed out by Ferre-Vilaplana (J. Phys. Chem. C 2008, 112, 3998) are discussed. In his calculations, this author used a finite coronene cluster, C...

  5. Comment on 'On higher order corrections to gyrokinetic Vlasov-Poisson equations in the long wavelength limit' [Phys. Plasmas 16, 044506 (2009)

    International Nuclear Information System (INIS)

    Parra, Felix I.; Catto, Peter J.

    2009-01-01

    A recent publication [F. I. Parra and P. J. Catto, Plasma Phys. Controlled Fusion 50, 065014 (2008)] warned against the use of the lower order gyrokinetic Poisson equation at long wavelengths because the long wavelength, radial electric field must remain undetermined to the order the equation is obtained. Another reference [W. W. Lee and R. A. Kolesnikov, Phys. Plasmas 16, 044506 (2009)] criticizes these results by arguing that the higher order terms neglected in the most common gyrokinetic Poisson equation are formally smaller than the terms that are retained. This argument is flawed and ignores that the lower order terms, although formally larger, must cancel without determining the long wavelength, radial electric field. The reason for this cancellation is discussed. In addition, the origin of a nonlinear term present in the gyrokinetic Poisson equation [F. I. Parra and P. J. Catto, Plasma Phys. Controlled Fusion 50, 065014 (2008)] is explained.

  6. Analysis of photon count data from single-molecule fluorescence experiments

    Science.gov (United States)

    Burzykowski, T.; Szubiakowski, J.; Rydén, T.

    2003-03-01

    We consider single-molecule fluorescence experiments with data in the form of counts of photons registered over multiple time-intervals. Based on the observation schemes, linking back to works by Dehmelt [Bull. Am. Phys. Soc. 20 (1975) 60] and Cook and Kimble [Phys. Rev. Lett. 54 (1985) 1023], we propose an analytical approach to the data based on the theory of Markov-modulated Poisson processes (MMPP). In particular, we consider maximum-likelihood estimation. The method is illustrated using a real-life dataset. Additionally, the properties of the proposed method are investigated through simulations and compared to two other approaches developed by Yip et al. [J. Phys. Chem. A 102 (1998) 7564] and Molski [Chem. Phys. Lett. 324 (2000) 301].

  7. Gas-phase chemistry of actinides ions: new insights into the reaction of UO+ and UO+2 with H2O

    International Nuclear Information System (INIS)

    Michelini, M.D.C.; Russo, N.; Sicilia, E.

    2007-01-01

    Complete text of publication follows: Reaction pathways for the interaction of uranium monoxide cations with water were studied by using different approaches of Density Functional Theory. Firstly, relativistic small-core pseudopotentials were used together with B3LYP hybrid functional. In addition, frozen-core PW91-PW91 calculations were performed within the ZORA approximation. A close description of the reaction mechanisms leading to different dissociation channels is presented, including all the involved minima and transition states [1]. Different possible spin states were considered as well as the effect of spin-orbit interactions (SO-ZORA) on the transition state barrier heights. The obtained results are compared with recent experimental data [2] as well as with previous theoretical studies of the reaction of bare uranium cations with water [3], in order to analyse the influence of the oxo-ligand in reactivity. References: [1] Michelini, M.C.; Russo, N.; Sicilia, E.J. Am. Chem. Soc., to be published; [2] (a) Jackson, G. P.; King, F. L.; Goeringer, D. E.; Duckworth, D. C. J. Phys. Chem. A 2002, 106, 7788; (b) Cornehl, H.H.; Wesendrup, R.; Diefenbach, M.; Schwarz, H. Chem. Eur. J. 1997, 3, 1083; (c) Gibson, J. K.; Haire, R. G.; Santos, M.; Marcalo, J.; Pires de Matos, A. J. Phys. Chem. A 2005, 109, 2768; [3] Michelini, M.C.; Russo, N.; Sicilia, E. Angew. Chem. Int. Ed., 2006, 45, 1095

  8. Nonlinear Corrections to Temperature in Computer Simulations of Complex Systems

    Science.gov (United States)

    2015-06-23

    Diezemann, G.; Geil, B.; Heuer, A.; Hinze, G.; Kuebler, S.C.; Richert, R.; Schiener, B.; Sillescu, H.; Spiess , H.W.; Tracht, U.; Wilhelm, M., Nature of the...frequency wing of supercooled glycerol, J. Chem. Phys. 2002, 118, 1356-1363 33 Reinsberg, S.A.; Heuer, A.; Doliwa, B.; Zimmermann, H.; Spiess , H.W...Rohr, K.; Spiess , H.W., Nature of nonexponential loss of correlation above the glass transition investigated by multidimensional NMR, Phys. Rev. Lett

  9. Thermophysical Properties of Matter - the TPRC Data Series. Volume 13. Thermal Expansion - Nonmetallic Solids

    Science.gov (United States)

    1977-01-01

    topography of the state of knowledge on the thermal expansion of nonmetallic solids. We believe there is also much food for reflec- West Lafayette...34 Lithium Silicates ......... 713 209 Magnesium Metasilicate MgSiO. .. ......... 715 210 Magnesium Orthosilicate Mg2 SiO . . . . . . . . . . . . 718 211...Antiferromagnetism of Praseodymium," Phys. Rev. Letters, 12(20), 553-5, 1964. 66. Goode, J.M., "Phase Transition Temperature of Polonium ,"J. Chem. Phys., 26(5), 1269

  10. On the use of polarization modulation in combined interferometry and polarimetry. Corrigendum. 1998 Plasma Phys. Control. Fusion, v. 40 p. 153-161

    International Nuclear Information System (INIS)

    Segre, S.E.

    1998-01-01

    Errors in the main text, the appendix and two curves are corrected in this corrigendum to the paper entitled ''On the use of polarization modulation in combined interferometry and polarimetry'', written by S.E. Segre and published in 1998 Plasma Phys. Control. Fusion, v. 40 p. 153-161

  11. Comment on 'Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential' [J. Math. Phys. 48, 073515 (2007)

    International Nuclear Information System (INIS)

    Castro, L. B.; Castro, A. S. de

    2010-01-01

    It is shown that the paper 'Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential' by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians.

  12. Comment on open-quote open-quote Bohm criterion for the collisional sheath close-quote close-quote [Phys. Plasmas 3, 1459 (1996)

    International Nuclear Information System (INIS)

    Riemann, K.U.; Meyer, P.

    1996-01-01

    Recently, Valentini [Phys. Plasmas 3, 1459 (1996)] investigated the influence of collisions on the space charge formation and derived a modified Bohm criterion accounting for collisions in the sheath. It is shown that this derivation is wrong and is based on a misinterpretation of the plasma sheath concept. copyright 1996 American Institute of Physics

  13. Comment on: Path integral solution of the Schroedinger equation in curvilinear coordinates: A straightforward procedure [J. Math. Phys. 37, 4310 endash 4319 (1996)

    International Nuclear Information System (INIS)

    Wurm, A.; LaChapelle, J.

    1997-01-01

    The authors comment on the paper by J. LaChapelle, J. Math. Phys. 37, 4310 (1996), and give explicit expressions for the parametrization, its solution, and the Lie derivatives of the Schroedinger equation for the case of n-dimensional spherical coordinates

  14. Erratum: Laser-Induced Graphite Plasma Kinetic Spectroscopy under Different Ambient Pressures [Chin. Phys. Lett. Vol. 32, No. 4, 043201(2015)

    International Nuclear Information System (INIS)

    Chaudhary, K.; Rosalan, S.; Aziz, M. S.; Bahadoran, M.; Ali, J; Bidin, N.; Saktioto; Yupapin, P. P.

    2015-01-01

    There is a typewriting mistake in our previous report [Chin. Phys. Lett. 32, 4 (2015) 043201], the name of the fourth author M. Bohadoran should be M. Bahadoran. We note that this mistake does not affect the conclusion of our report, and apologize for any inconvenience for readers caused by our oversight. (paper)

  15. Erratum to “Neutron–19C scattering: Emergence of universal properties in a finite range potential” [Phys. Lett. B 764 (2017 196

    Directory of Open Access Journals (Sweden)

    M.A. Shalchi

    2017-08-01

    Full Text Available Numerical results for the function (1−EK/E0kcot⁡δ0R, as given in Phys. Lett. B 764 (2017 196, are revised. Fig. 2 and Tables 2 and 3 should be replaced by the following corresponding figure and tables. The conclusions of the original paper remain unchanged.

  16. New "Tau-Leap" Strategy for Accelerated Stochastic Simulation.

    Science.gov (United States)

    Ramkrishna, Doraiswami; Shu, Che-Chi; Tran, Vu

    2014-12-10

    The "Tau-Leap" strategy for stochastic simulations of chemical reaction systems due to Gillespie and co-workers has had considerable impact on various applications. This strategy is reexamined with Chebyshev's inequality for random variables as it provides a rigorous probabilistic basis for a measured τ-leap thus adding significantly to simulation efficiency. It is also shown that existing strategies for simulation times have no probabilistic assurance that they satisfy the τ-leap criterion while the use of Chebyshev's inequality leads to a specified degree of certainty with which the τ-leap criterion is satisfied. This reduces the loss of sample paths which do not comply with the τ-leap criterion. The performance of the present algorithm is assessed, with respect to one discussed by Cao et al. ( J. Chem. Phys. 2006 , 124 , 044109), a second pertaining to binomial leap (Tian and Burrage J. Chem. Phys. 2004 , 121 , 10356; Chatterjee et al. J. Chem. Phys. 2005 , 122 , 024112; Peng et al. J. Chem. Phys. 2007 , 126 , 224109), and a third regarding the midpoint Poisson leap (Peng et al., 2007; Gillespie J. Chem. Phys. 2001 , 115 , 1716). The performance assessment is made by estimating the error in the histogram measured against that obtained with the so-called stochastic simulation algorithm. It is shown that the current algorithm displays notably less histogram error than its predecessor for a fixed computation time and, conversely, less computation time for a fixed accuracy. This computational advantage is an asset in repetitive calculations essential for modeling stochastic systems. The importance of stochastic simulations is derived from diverse areas of application in physical and biological sciences, process systems, and economics, etc. Computational improvements such as those reported herein are therefore of considerable significance.

  17. Electrostatic Plugging of Multidipole Cusps.

    Science.gov (United States)

    1982-05-01

    8217, -) V0 100 I-’ 60 00 0> :oc 0 \\0H U 0 0- 0- -L 0 0- P4 A- 602- 179 MASS SPECTROMETER CIRCUIT CHME P OGA- SWOT Figue 1. Shemaic f eteralXly...2R. L. Hirsch, J. Appl . Phys. 38, 4522 (1967). 3N. Hershkowitz K. N. Leung, and T. Romesser, Phys. Rev. Lett. 5. 277 (1975 1. 4A. Kitsunezaki, M...R. T. Carpenter, submitted to J. Appl . Phys. 1OD. Rapp and P. Englander-Golden, J. Chem. Phys. 3, 1464 (1965). "A. Lang and N. Hershkowitz, J. Appl

  18. Electron Energy Deposition in Atomic Nitrogen

    Science.gov (United States)

    1987-10-06

    Jackman , and A.E.S. Green, J. Chem. Phys. 65, 154 (1976). 10. R.H. Garvey, H.S. Porter, and A.E.S. Green, J. Appl. Phys. 48, 4353 (1977). 11. R.B...Stolarski, J. Atmos. Terr. Phys. 34, 1703 (1972). 29. A.E.S. Green and T. Savada, J. Atmos. Terr. Phys. 34, 1719 (1972). 30. C.H. Jackman , R.1...S.E. Albuquerque, H 87106 Physics International, Inc. Attn: Dr. Brendan Godfrey 2700 Merced Street Dr. Thomas Hughes San Leandro, CA. 94577 Dr

  19. Reactivity of Metal Nitrates.

    Science.gov (United States)

    1982-07-20

    02NOCuOH Any mechanism suggested for the nitration of aromatic systems by titanium(IV) nitrate must take into account the observed similarity, in...occurs. -26- References 1. For recent reviews see (a) R. B. Moodie and K. Schofield, Accounts Chem. Res., 1976, 9, 287; (b) G. A. Olah and S. J. Kuhn...Ithaca, N.Y., 1969, Chapter VI; L. M. Stock, Prog. Phys. Org. Chem., 1976, 12, 21; J. G. Hoggett , R. B. Moodie, J. R. Penton, and K. Schofield

  20. Energetic, electronic and optical properties of lanthanide doped TiO2: An ab initio LDA+U study

    CSIR Research Space (South Africa)

    Mulwa, WM

    2016-05-01

    Full Text Available potential, J. Chem. Phys. 118 (2003) 8207. doi:10.1063/1.1564060. [23] X. Ren, Beyond LDA and GGA - Tackling exact exchange , hybrid functional , MP2 , and RPA with numeric atom-centered orbitals The Fritz-Haber-Institute ab initio molecular simulations.... Calzolari, A. Ruini, A. Catellani, Anchor Group versus Conjugation: Toward the Gap-State Engineering of Functionalized ZnO (101̅0) Surface for Optoelectronic Applications, J. Am. Chem. Soc. 133 (2011) 5893–5899. [36] R. Gillen, S.J. Clark, J. Robertson...