WorldWideScience

Sample records for computational chemistry experimental

  1. Transuranic Computational Chemistry.

    Science.gov (United States)

    Kaltsoyannis, Nikolas

    2018-02-26

    Recent developments in the chemistry of the transuranic elements are surveyed, with particular emphasis on computational contributions. Examples are drawn from molecular coordination and organometallic chemistry, and from the study of extended solid systems. The role of the metal valence orbitals in covalent bonding is a particular focus, especially the consequences of the stabilization of the 5f orbitals as the actinide series is traversed. The fledgling chemistry of transuranic elements in the +II oxidation state is highlighted. Throughout, the symbiotic interplay of experimental and computational studies is emphasized; the extraordinary challenges of experimental transuranic chemistry afford computational chemistry a particularly valuable role at the frontier of the periodic table. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Computational Chemistry Comparison and Benchmark Database

    Science.gov (United States)

    SRD 101 NIST Computational Chemistry Comparison and Benchmark Database (Web, free access)   The NIST Computational Chemistry Comparison and Benchmark Database is a collection of experimental and ab initio thermochemical properties for a selected set of molecules. The goals are to provide a benchmark set of molecules for the evaluation of ab initio computational methods and allow the comparison between different ab initio computational methods for the prediction of thermochemical properties.

  3. Recent development in computational actinide chemistry

    International Nuclear Information System (INIS)

    Li Jun

    2008-01-01

    Ever since the Manhattan project in World War II, actinide chemistry has been essential for nuclear science and technology. Yet scientists still seek the ability to interpret and predict chemical and physical properties of actinide compounds and materials using first-principle theory and computational modeling. Actinide compounds are challenging to computational chemistry because of their complicated electron correlation effects and relativistic effects, including spin-orbit coupling effects. There have been significant developments in theoretical studies on actinide compounds in the past several years. The theoretical capabilities coupled with new experimental characterization techniques now offer a powerful combination for unraveling the complexities of actinide chemistry. In this talk, we will provide an overview of our own research in this field, with particular emphasis on applications of relativistic density functional and ab initio quantum chemical methods to the geometries, electronic structures, spectroscopy and excited-state properties of small actinide molecules such as CUO and UO 2 and some large actinide compounds relevant to separation and environment science. The performance of various density functional approaches and wavefunction theory-based electron correlation methods will be compared. The results of computational modeling on the vibrational, electronic, and NMR spectra of actinide compounds will be briefly discussed as well [1-4]. We will show that progress in relativistic quantum chemistry, computer hardware and computational chemistry software has enabled computational actinide chemistry to emerge as a powerful and predictive tool for research in actinide chemistry. (authors)

  4. Relativistic quantum chemistry on quantum computers

    DEFF Research Database (Denmark)

    Veis, L.; Visnak, J.; Fleig, T.

    2012-01-01

    The past few years have witnessed a remarkable interest in the application of quantum computing for solving problems in quantum chemistry more efficiently than classical computers allow. Very recently, proof-of-principle experimental realizations have been reported. However, so far only...... the nonrelativistic regime (i.e., the Schrodinger equation) has been explored, while it is well known that relativistic effects can be very important in chemistry. We present a quantum algorithm for relativistic computations of molecular energies. We show how to efficiently solve the eigenproblem of the Dirac......-Coulomb Hamiltonian on a quantum computer and demonstrate the functionality of the proposed procedure by numerical simulations of computations of the spin-orbit splitting in the SbH molecule. Finally, we propose quantum circuits with three qubits and nine or ten controlled-NOT (CNOT) gates, which implement a proof...

  5. Quantum chemistry simulation on quantum computers: theories and experiments.

    Science.gov (United States)

    Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-07-14

    It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

  6. Integration of Computational Chemistry into the Undergraduate Organic Chemistry Laboratory Curriculum

    Science.gov (United States)

    Esselman, Brian J.; Hill, Nicholas J.

    2016-01-01

    Advances in software and hardware have promoted the use of computational chemistry in all branches of chemical research to probe important chemical concepts and to support experimentation. Consequently, it has become imperative that students in the modern undergraduate curriculum become adept at performing simple calculations using computational…

  7. Computational chemistry

    Science.gov (United States)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  8. Computational chemistry research

    Science.gov (United States)

    Levin, Eugene

    1987-01-01

    Task 41 is composed of two parts: (1) analysis and design studies related to the Numerical Aerodynamic Simulation (NAS) Extended Operating Configuration (EOC) and (2) computational chemistry. During the first half of 1987, Dr. Levin served as a member of an advanced system planning team to establish the requirements, goals, and principal technical characteristics of the NAS EOC. A paper entitled 'Scaling of Data Communications for an Advanced Supercomputer Network' is included. The high temperature transport properties (such as viscosity, thermal conductivity, etc.) of the major constituents of air (oxygen and nitrogen) were correctly determined. The results of prior ab initio computer solutions of the Schroedinger equation were combined with the best available experimental data to obtain complete interaction potentials for both neutral and ion-atom collision partners. These potentials were then used in a computer program to evaluate the collision cross-sections from which the transport properties could be determined. A paper entitled 'High Temperature Transport Properties of Air' is included.

  9. Exercises in Computational Chemistry

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16).......A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16)....

  10. Using Computer Simulations in Chemistry Problem Solving

    Science.gov (United States)

    Avramiotis, Spyridon; Tsaparlis, Georgios

    2013-01-01

    This study is concerned with the effects of computer simulations of two novel chemistry problems on the problem solving ability of students. A control-experimental group, equalized by pair groups (n[subscript Exp] = n[subscript Ctrl] = 78), research design was used. The students had no previous experience of chemical practical work. Student…

  11. Computational quantum chemistry website

    International Nuclear Information System (INIS)

    1997-01-01

    This report contains the contents of a web page related to research on the development of quantum chemistry methods for computational thermochemistry and the application of quantum chemistry methods to problems in material chemistry and chemical sciences. Research programs highlighted include: Gaussian-2 theory; Density functional theory; Molecular sieve materials; Diamond thin-film growth from buckyball precursors; Electronic structure calculations on lithium polymer electrolytes; Long-distance electronic coupling in donor/acceptor molecules; and Computational studies of NOx reactions in radioactive waste storage

  12. Implementing and Operating Computer Graphics in the Contemporary Chemistry Education

    Directory of Open Access Journals (Sweden)

    Olga Popovska

    2017-11-01

    Full Text Available Technology plays a crucial role in modern teaching, providing both, educators and students fundamental theoretical insights as well as supporting the interpretation of experimental data. In the long term it gives students a clear stake in their learning processes. Advancing in education furthermore largely depends on providing valuable experiences and tools throughout digital and computer literacy. Here and after, the computer’s benefit makes no exception in the chemistry as a science. The major part of computer revolutionizing in the chemistry laboratory is with the use of images, diagrams, molecular models, graphs and specialized chemistry programs. In the sense of this, the teacher provides more interactive classes and numerous dynamic teaching methods along with advanced technology. All things considered, the aim of this article is to implement interactive teaching methods of chemistry subjects using chemistry computer graphics. A group of students (n = 30 at the age of 18–20 were testing using methods such as brainstorming, demonstration, working in pairs, and writing laboratory notebooks. The results showed that demonstration is the most acceptable interactive method (95%. This article is expected to be of high value to teachers and researchers of chemistry, implementing interactive methods, and operating computer graphics.

  13. Integrating medicinal chemistry, organic/combinatorial chemistry, and computational chemistry for the discovery of selective estrogen receptor modulators with Forecaster, a novel platform for drug discovery.

    Science.gov (United States)

    Therrien, Eric; Englebienne, Pablo; Arrowsmith, Andrew G; Mendoza-Sanchez, Rodrigo; Corbeil, Christopher R; Weill, Nathanael; Campagna-Slater, Valérie; Moitessier, Nicolas

    2012-01-23

    As part of a large medicinal chemistry program, we wish to develop novel selective estrogen receptor modulators (SERMs) as potential breast cancer treatments using a combination of experimental and computational approaches. However, one of the remaining difficulties nowadays is to fully integrate computational (i.e., virtual, theoretical) and medicinal (i.e., experimental, intuitive) chemistry to take advantage of the full potential of both. For this purpose, we have developed a Web-based platform, Forecaster, and a number of programs (e.g., Prepare, React, Select) with the aim of combining computational chemistry and medicinal chemistry expertise to facilitate drug discovery and development and more specifically to integrate synthesis into computer-aided drug design. In our quest for potent SERMs, this platform was used to build virtual combinatorial libraries, filter and extract a highly diverse library from the NCI database, and dock them to the estrogen receptor (ER), with all of these steps being fully automated by computational chemists for use by medicinal chemists. As a result, virtual screening of a diverse library seeded with active compounds followed by a search for analogs yielded an enrichment factor of 129, with 98% of the seeded active compounds recovered, while the screening of a designed virtual combinatorial library including known actives yielded an area under the receiver operating characteristic (AU-ROC) of 0.78. The lead optimization proved less successful, further demonstrating the challenge to simulate structure activity relationship studies.

  14. Disciplines, models, and computers: the path to computational quantum chemistry.

    Science.gov (United States)

    Lenhard, Johannes

    2014-12-01

    Many disciplines and scientific fields have undergone a computational turn in the past several decades. This paper analyzes this sort of turn by investigating the case of computational quantum chemistry. The main claim is that the transformation from quantum to computational quantum chemistry involved changes in three dimensions. First, on the side of instrumentation, small computers and a networked infrastructure took over the lead from centralized mainframe architecture. Second, a new conception of computational modeling became feasible and assumed a crucial role. And third, the field of computa- tional quantum chemistry became organized in a market-like fashion and this market is much bigger than the number of quantum theory experts. These claims will be substantiated by an investigation of the so-called density functional theory (DFT), the arguably pivotal theory in the turn to computational quantum chemistry around 1990.

  15. Effects of Computer Based Learning on Students' Attitudes and Achievements towards Analytical Chemistry

    Science.gov (United States)

    Akcay, Husamettin; Durmaz, Asli; Tuysuz, Cengiz; Feyzioglu, Burak

    2006-01-01

    The aim of this study was to compare the effects of computer-based learning and traditional method on students' attitudes and achievement towards analytical chemistry. Students from Chemistry Education Department at Dokuz Eylul University (D.E.U) were selected randomly and divided into three groups; two experimental (Eg-1 and Eg-2) and a control…

  16. The role of computational chemistry in the science and measurements of the atmosphere

    Science.gov (United States)

    Phillips, D. H.

    1978-01-01

    The role of computational chemistry in determining the stability, photochemistry, spectroscopic parameters, and parameters for estimating reaction rates of atmospheric constituents is discussed. Examples dealing with the photolysis cross sections of HOCl and (1 Delta g) O2 and with the stability of gaseous NH4Cl and asymmetric ClO3 are presented. It is concluded that computational chemistry can play an important role in the study of atmospheric constituents, particularly reactive and short-lived species which are difficult to investigate experimentally.

  17. A DFT-Based Computational-Experimental Methodology for Synthetic Chemistry: Example of Application to the Catalytic Opening of Epoxides by Titanocene.

    Science.gov (United States)

    Jaraíz, Martín; Enríquez, Lourdes; Pinacho, Ruth; Rubio, José E; Lesarri, Alberto; López-Pérez, José L

    2017-04-07

    A novel DFT-based Reaction Kinetics (DFT-RK) simulation approach, employed in combination with real-time data from reaction monitoring instrumentation (like UV-vis, FTIR, Raman, and 2D NMR benchtop spectrometers), is shown to provide a detailed methodology for the analysis and design of complex synthetic chemistry schemes. As an example, it is applied to the opening of epoxides by titanocene in THF, a catalytic system with abundant experimental data available. Through a DFT-RK analysis of real-time IR data, we have developed a comprehensive mechanistic model that opens new perspectives to understand previous experiments. Although derived specifically from the opening of epoxides, the prediction capabilities of the model, built on elementary reactions, together with its practical side (reaction kinetics simulations of real experimental conditions) make it a useful simulation tool for the design of new experiments, as well as for the conception and development of improved versions of the reagents. From the perspective of the methodology employed, because both the computational (DFT-RK) and the experimental (spectroscopic data) components can follow the time evolution of several species simultaneously, it is expected to provide a helpful tool for the study of complex systems in synthetic chemistry.

  18. Virtually going green: The role of quantum computational chemistry in reducing pollution and toxicity in chemistry

    Science.gov (United States)

    Stevens, Jonathan

    2017-07-01

    Continuing advances in computational chemistry has permitted quantum mechanical calculation to assist in research in green chemistry and to contribute to the greening of chemical practice. Presented here are recent examples illustrating the contribution of computational quantum chemistry to green chemistry, including the possibility of using computation as a green alternative to experiments, but also illustrating contributions to greener catalysis and the search for greener solvents. Examples of applications of computation to ambitious projects for green synthetic chemistry using carbon dioxide are also presented.

  19. 24th Current Trends in Computational Chemistry

    Science.gov (United States)

    2017-05-17

    Corps of Engineers Army Research Office Conference on Current Trends in Computational Chemistry 2016 NOVEMBER 11-12, 2016 JACKSON, MS... Chemistry and Biochemistry Jackson, MS 39217 U.S.A. Tel: 6019793723 E-mail: shonda@icnanotox.org Richard Alo Dean College of Science, Engineering ...Report: 24th Current Trends in Computational Chemistry The views, opinions and/or findings contained in this report are those of the author(s) and should

  20. FPS scientific and supercomputers computers in chemistry

    International Nuclear Information System (INIS)

    Curington, I.J.

    1987-01-01

    FPS Array Processors, scientific computers, and highly parallel supercomputers are used in nearly all aspects of compute-intensive computational chemistry. A survey is made of work utilizing this equipment, both published and current research. The relationship of the computer architecture to computational chemistry is discussed, with specific reference to Molecular Dynamics, Quantum Monte Carlo simulations, and Molecular Graphics applications. Recent installations of the FPS T-Series are highlighted, and examples of Molecular Graphics programs running on the FPS-5000 are shown

  1. Exploiting Locality in Quantum Computation for Quantum Chemistry.

    Science.gov (United States)

    McClean, Jarrod R; Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán

    2014-12-18

    Accurate prediction of chemical and material properties from first-principles quantum chemistry is a challenging task on traditional computers. Recent developments in quantum computation offer a route toward highly accurate solutions with polynomial cost; however, this solution still carries a large overhead. In this Perspective, we aim to bring together known results about the locality of physical interactions from quantum chemistry with ideas from quantum computation. We show that the utilization of spatial locality combined with the Bravyi-Kitaev transformation offers an improvement in the scaling of known quantum algorithms for quantum chemistry and provides numerical examples to help illustrate this point. We combine these developments to improve the outlook for the future of quantum chemistry on quantum computers.

  2. Integrating Computational Chemistry into a Course in Classical Thermodynamics

    Science.gov (United States)

    Martini, Sheridan R.; Hartzell, Cynthia J.

    2015-01-01

    Computational chemistry is commonly addressed in the quantum mechanics course of undergraduate physical chemistry curricula. Since quantum mechanics traditionally follows the thermodynamics course, there is a lack of curricula relating computational chemistry to thermodynamics. A method integrating molecular modeling software into a semester long…

  3. Computational materials chemistry for carbon capture using porous materials

    International Nuclear Information System (INIS)

    Sharma, Abhishek; Malani, Ateeque; Huang, Runhong; Babarao, Ravichandar

    2017-01-01

    Control over carbon dioxide (CO 2 ) release is extremely important to decrease its hazardous effects on the environment such as global warming, ocean acidification, etc. For CO 2 capture and storage at industrial point sources, nanoporous materials offer an energetically viable and economically feasible approach compared to chemisorption in amines. There is a growing need to design and synthesize new nanoporous materials with enhanced capability for carbon capture. Computational materials chemistry offers tools to screen and design cost-effective materials for CO 2 separation and storage, and it is less time consuming compared to trial and error experimental synthesis. It also provides a guide to synthesize new materials with better properties for real world applications. In this review, we briefly highlight the various carbon capture technologies and the need of computational materials design for carbon capture. This review discusses the commonly used computational chemistry-based simulation methods for structural characterization and prediction of thermodynamic properties of adsorbed gases in porous materials. Finally, simulation studies reported on various potential porous materials, such as zeolites, porous carbon, metal organic frameworks (MOFs) and covalent organic frameworks (COFs), for CO 2 capture are discussed. (topical review)

  4. Computational chemistry at the petascale: Are we there yet?

    International Nuclear Information System (INIS)

    Apra, E; Harrison, R J; Shelton, W A; Tipparaju, V; Vazquez-Mayagoitia, A

    2009-01-01

    We have run computational chemistry calculations approaching the Petascale level of performance (∼ 0.5 PFlops). We used the Coupled Cluster CCSD(T) module of the computational chemistry code NWChem to evaluate accurate energetics of water clusters on a 1.4 PFlops Cray XT5 computer.

  5. Superheavy Elements Challenge Experimental and Theoretical Chemistry

    CERN Document Server

    Zvára, I

    2003-01-01

    When reflecting on the story of superheavy elements, the an experimenter, acknowledges the role, which the predictions of nuclear and chemical theories have played in ongoing studies. Today, the problems of major interest for experimental chemistry are the studies of elements 112 and 114 including their chemical identification. Advanced quantum chemistry calculations of atoms and molecules would be of much help. First experiments with element 112 evidence that the metal is much more volatile and inert than mercury.

  6. Analysis of irradiated biogenic amines by computational chemistry and spectroscopy

    International Nuclear Information System (INIS)

    Oliveira, Jorge L.S.P.; Borges Junior, Itamar; Cardozo, Monique; Souza, Stefania P.; Lima, Antonio L.S.; Lima, Keila S.C.

    2011-01-01

    Biogenic Amines (B A) are nitrogenous compounds able to cause food poisoning. In this work, we studied the tyramine, one of the most common BA present in foods by combining experimental measured IR (Infrared) and GC/MS (Gas Chromatograph / Mass Spectrometry) spectra and computational quantum chemistry. Density Functional Theory (DFT) and the Deformed Atoms in Molecules (DMA) method was used to compute the partition the electronic densities in a chemically-intuitive way and electrostatic potentials of molecule to identify the acid and basic sites. Trading pattern was irradiated using a Cs 137 radiator, and each sample was identified by IR and GC/MS. Calculated and experimental IR spectra were compared. We observed that ionizing gamma irradiation was very effective in decreasing the population of standard amine, resulting in fragments that could be rationalized through the quantum chemistry calculations. In particular, we could locate the acid and basic sites of both molecules and identify possible sites of structural weaknesses, which allowed to propose mechanistic schemes for the breaking of chemical bonds by the irradiation. Moreover, from this work we hope it will be also possible to properly choose the dose of gamma irradiation which should be provided to eliminate each type of contamination. (author)

  7. Deep learning for computational chemistry.

    Science.gov (United States)

    Goh, Garrett B; Hodas, Nathan O; Vishnu, Abhinav

    2017-06-15

    The rise and fall of artificial neural networks is well documented in the scientific literature of both computer science and computational chemistry. Yet almost two decades later, we are now seeing a resurgence of interest in deep learning, a machine learning algorithm based on multilayer neural networks. Within the last few years, we have seen the transformative impact of deep learning in many domains, particularly in speech recognition and computer vision, to the extent that the majority of expert practitioners in those field are now regularly eschewing prior established models in favor of deep learning models. In this review, we provide an introductory overview into the theory of deep neural networks and their unique properties that distinguish them from traditional machine learning algorithms used in cheminformatics. By providing an overview of the variety of emerging applications of deep neural networks, we highlight its ubiquity and broad applicability to a wide range of challenges in the field, including quantitative structure activity relationship, virtual screening, protein structure prediction, quantum chemistry, materials design, and property prediction. In reviewing the performance of deep neural networks, we observed a consistent outperformance against non-neural networks state-of-the-art models across disparate research topics, and deep neural network-based models often exceeded the "glass ceiling" expectations of their respective tasks. Coupled with the maturity of GPU-accelerated computing for training deep neural networks and the exponential growth of chemical data on which to train these networks on, we anticipate that deep learning algorithms will be a valuable tool for computational chemistry. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. Computational Chemistry in the Pharmaceutical Industry: From Childhood to Adolescence.

    Science.gov (United States)

    Hillisch, Alexander; Heinrich, Nikolaus; Wild, Hanno

    2015-12-01

    Computational chemistry within the pharmaceutical industry has grown into a field that proactively contributes to many aspects of drug design, including target selection and lead identification and optimization. While methodological advancements have been key to this development, organizational developments have been crucial to our success as well. In particular, the interaction between computational and medicinal chemistry and the integration of computational chemistry into the entire drug discovery process have been invaluable. Over the past ten years we have shaped and developed a highly efficient computational chemistry group for small-molecule drug discovery at Bayer HealthCare that has significantly impacted the clinical development pipeline. In this article we describe the setup and tasks of the computational group and discuss external collaborations. We explain what we have found to be the most valuable and productive methods and discuss future directions for computational chemistry method development. We share this information with the hope of igniting interesting discussions around this topic. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. computational chemistry capacity building in an underprivileged ...

    African Journals Online (AJOL)

    dell

    ABSTRACT. Computational chemistry is a fast developing branch of modern chemistry, focusing on the study of molecules to enable better understanding of the properties of substances. Its applications comprise a variety of fields, from drug design to the design of compounds with desired properties. (e.g., catalysts with ...

  10. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    Science.gov (United States)

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  11. 40 CFR 158.270 - Experimental use permit data requirements for residue chemistry.

    Science.gov (United States)

    2010-07-01

    ... requirements for residue chemistry. 158.270 Section 158.270 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for residue chemistry. All residue chemistry data, as described in... section 408(r) is sought. Residue chemistry data are not required for an experimental use permit issued on...

  12. The Use of Modular Computer-Based Lessons in a Modification of the Classical Introductory Course in Organic Chemistry.

    Science.gov (United States)

    Stotter, Philip L.; Culp, George H.

    An experimental course in organic chemistry utilized computer-assisted instructional (CAI) techniques. The CAI lessons provided tutorial drill and practice and simulated experiments and reactions. The Conversational Language for Instruction and Computing was used, along with a CDC 6400-6600 system; students scheduled and completed the lessons at…

  13. The performance of low-cost commercial cloud computing as an alternative in computational chemistry.

    Science.gov (United States)

    Thackston, Russell; Fortenberry, Ryan C

    2015-05-05

    The growth of commercial cloud computing (CCC) as a viable means of computational infrastructure is largely unexplored for the purposes of quantum chemistry. In this work, the PSI4 suite of computational chemistry programs is installed on five different types of Amazon World Services CCC platforms. The performance for a set of electronically excited state single-point energies is compared between these CCC platforms and typical, "in-house" physical machines. Further considerations are made for the number of cores or virtual CPUs (vCPUs, for the CCC platforms), but no considerations are made for full parallelization of the program (even though parallelization of the BLAS library is implemented), complete high-performance computing cluster utilization, or steal time. Even with this most pessimistic view of the computations, CCC resources are shown to be more cost effective for significant numbers of typical quantum chemistry computations. Large numbers of large computations are still best utilized by more traditional means, but smaller-scale research may be more effectively undertaken through CCC services. © 2015 Wiley Periodicals, Inc.

  14. Medicinal electrochemistry: integration of electrochemistry, medicinal chemistry and computational chemistry.

    Science.gov (United States)

    Almeida, M O; Maltarollo, V G; de Toledo, R A; Shim, H; Santos, M C; Honorio, K M

    2014-01-01

    Over the last centuries, there were many important discoveries in medicine that were crucial for gaining a better understanding of several physiological processes. Molecular modelling techniques are powerful tools that have been successfully used to analyse and interface medicinal chemistry studies with electrochemical experimental results. This special combination can help to comprehend medicinal chemistry problems, such as predicting biological activity and understanding drug action mechanisms. Electrochemistry has provided better comprehension of biological reactions and, as a result of many technological improvements, the combination of electrochemical techniques and biosensors has become an appealing choice for pharmaceutical and biomedical analyses. Therefore, this review will briefly outline the present scope and future advances related to the integration of electrochemical and medicinal chemistry approaches based on various applications from recent studies.

  15. Mathematical challenges from theoretical/computational chemistry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The committee believes that this report has relevance and potentially valuable suggestions for a wide range of readers. Target audiences include: graduate departments in the mathematical and chemical sciences; federal and private agencies that fund research in the mathematical and chemical sciences; selected industrial and government research and development laboratories; developers of software and hardware for computational chemistry; and selected individual researchers. Chapter 2 of this report covers some history of computational chemistry for the nonspecialist, while Chapter 3 illustrates the fruits of some past successful cross-fertilization between mathematical scientists and computational/theoretical chemists. In Chapter 4 the committee has assembled a representative, but not exhaustive, survey of research opportunities. Most of these are descriptions of important open problems in computational/theoretical chemistry that could gain much from the efforts of innovative mathematical scientists, written so as to be accessible introductions to the nonspecialist. Chapter 5 is an assessment, necessarily subjective, of cultural differences that must be overcome if collaborative work is to be encouraged between the mathematical and the chemical communities. Finally, the report ends with a brief list of conclusions and recommendations that, if followed, could promote accelerated progress at this interface. Recognizing that bothersome language issues can inhibit prospects for collaborative research at the interface between distinctive disciplines, the committee has attempted throughout to maintain an accessible style, in part by using illustrative boxes, and has included at the end of the report a glossary of technical terms that may be familiar to only a subset of the target audiences listed above.

  16. 40 CFR 158.210 - Experimental use permit data requirements for product chemistry.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Experimental use permit data requirements for product chemistry. 158.210 Section 158.210 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for product chemistry. All product chemistry data, as described in...

  17. Deep learning for computational chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Garrett B. [Advanced Computing, Mathematics, and Data Division, Pacific Northwest National Laboratory, 902 Battelle Blvd Richland Washington 99354; Hodas, Nathan O. [Advanced Computing, Mathematics, and Data Division, Pacific Northwest National Laboratory, 902 Battelle Blvd Richland Washington 99354; Vishnu, Abhinav [Advanced Computing, Mathematics, and Data Division, Pacific Northwest National Laboratory, 902 Battelle Blvd Richland Washington 99354

    2017-03-08

    The rise and fall of artificial neural networks is well documented in the scientific literature of both the fields of computer science and computational chemistry. Yet almost two decades later, we are now seeing a resurgence of interest in deep learning, a machine learning algorithm based on “deep” neural networks. Within the last few years, we have seen the transformative impact of deep learning the computer science domain, notably in speech recognition and computer vision, to the extent that the majority of practitioners in those field are now regularly eschewing prior established models in favor of deep learning models. In this review, we provide an introductory overview into the theory of deep neural networks and their unique properties as compared to traditional machine learning algorithms used in cheminformatics. By providing an overview of the variety of emerging applications of deep neural networks, we highlight its ubiquity and broad applicability to a wide range of challenges in the field, including QSAR, virtual screening, protein structure modeling, QM calculations, materials synthesis and property prediction. In reviewing the performance of deep neural networks, we observed a consistent outperformance against non neural networks state-of-the-art models across disparate research topics, and deep neural network based models often exceeded the “glass ceiling” expectations of their respective tasks. Coupled with the maturity of GPU-accelerated computing for training deep neural networks and the exponential growth of chemical data on which to train these networks on, we anticipate that deep learning algorithms will be a useful tool and may grow into a pivotal role for various challenges in the computational chemistry field.

  18. What influences on demonstration experimental work in chemistry classroom?

    OpenAIRE

    Logar, Ana; Ferk Savec, Vesna

    2016-01-01

    Teachers and researchers agree that experimental work has a crucial role in teaching and learning of science. The article presents results of a qualitative investigation dealing with factors that influence on the efficiency of primary school students` experimental work in chemistry classroom. The sample consisted of 9 chemistry teachers and 141 randomly selected primary school students (age 13-14 years). Based on the research results a model for effective planning and integration of students`...

  19. From transistor to trapped-ion computers for quantum chemistry.

    Science.gov (United States)

    Yung, M-H; Casanova, J; Mezzacapo, A; McClean, J; Lamata, L; Aspuru-Guzik, A; Solano, E

    2014-01-07

    Over the last few decades, quantum chemistry has progressed through the development of computational methods based on modern digital computers. However, these methods can hardly fulfill the exponentially-growing resource requirements when applied to large quantum systems. As pointed out by Feynman, this restriction is intrinsic to all computational models based on classical physics. Recently, the rapid advancement of trapped-ion technologies has opened new possibilities for quantum control and quantum simulations. Here, we present an efficient toolkit that exploits both the internal and motional degrees of freedom of trapped ions for solving problems in quantum chemistry, including molecular electronic structure, molecular dynamics, and vibronic coupling. We focus on applications that go beyond the capacity of classical computers, but may be realizable on state-of-the-art trapped-ion systems. These results allow us to envision a new paradigm of quantum chemistry that shifts from the current transistor to a near-future trapped-ion-based technology.

  20. Computational chemistry reviews of current trends v.4

    CERN Document Server

    1999-01-01

    This volume presents a balanced blend of methodological and applied contributions. It supplements well the first three volumes of the series, revealing results of current research in computational chemistry. It also reviews the topographical features of several molecular scalar fields. A brief discussion of topographical concepts is followed by examples of their application to several branches of chemistry.The size of a basis set applied in a calculation determines the amount of computer resources necessary for a particular task. The details of a common strategy - the ab initio model potential

  1. Relativistic quantum chemistry on quantum computers

    Czech Academy of Sciences Publication Activity Database

    Veis, Libor; Višňák, Jakub; Fleig, T.; Knecht, S.; Saue, T.; Visscher, L.; Pittner, Jiří

    2012-01-01

    Roč. 85, č. 3 (2012), 030304 ISSN 1050-2947 R&D Projects: GA ČR GA203/08/0626 Institutional support: RVO:61388955 Keywords : simulation * algorithm * computation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.042, year: 2012

  2. 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.

  3. 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.

  4. Web-Based Job Submission Interface for the GAMESS Computational Chemistry Program

    Science.gov (United States)

    Perri, M. J.; Weber, S. H.

    2014-01-01

    A Web site is described that facilitates use of the free computational chemistry software: General Atomic and Molecular Electronic Structure System (GAMESS). Its goal is to provide an opportunity for undergraduate students to perform computational chemistry experiments without the need to purchase expensive software.

  5. An Insight into Flotation Chemistry of Pyrite with Isomeric Xanthates: A Combined Experimental and Computational Study

    Directory of Open Access Journals (Sweden)

    Guihong Han

    2018-04-01

    Full Text Available The flotation chemistry between pyrite and isomeric xanthates (butyl xanthate and isobutyl xanthate was investigated by means of adsorption experiments, surface tension tests, and molecular dynamic simulations in this work. The flotation chemical results were confirmed and further interpreted by quantum chemical calculations. The experiment results demonstrated that the isobutyl xanthate exhibited superior adsorption capacity and surface activity than those of butyl xanthate in flotation chemistry. In addition, molecular dynamic simulations were simultaneously performed in constant number, constant volume and temperature (NVT, and constant number, constant volume, and pressure (NPT ensemble, indicating that the NPT ensemble was more suitable to the flotation system and the isobutyl xanthate was easier to be adsorbed on pyrite surface compared with butyl xanthate during an appropriate range of concentrations. Furthermore, the quantum chemical calculations elucidated that the isobutyl xanthate presented higher reactivity than that of the corresponding butyl xanthate based on the frontier molecular orbital theory of chemical reactivity, which was consistent with experimental and simulation results obtained. This work can provide theoretical guidance for an in-depth study of the flotation chemistry of pyrite with isomeric xanthates.

  6. Computer assisted instruction in the general chemistry laboratory

    Science.gov (United States)

    Pate, Jerry C.

    This dissertation examines current applications concerning the use of computer technology to enhance instruction in the general chemistry laboratory. The dissertation critiques widely-used educational software, and explores examples of multimedia presentations such as those used in beginning chemistry laboratory courses at undergraduate and community colleges. The dissertation describes a prototype compact disc (CD) used to (a) introduce the general chemistry laboratory, (b) familiarize students with using chemistry laboratory equipment, (c) introduce laboratory safety practices, and (d) provide approved techniques for maintaining a laboratory notebook. Upon completing the CD portion of the pre-lab, students are linked to individual self-help (WebCT) quizzes covering the information provided on the CD. The CD is designed to improve student understanding of basic concepts, techniques, and procedures used in the general chemistry laboratory.

  7. The defect chemistry of nitrogen in oxides: A review of experimental and theoretical studies

    International Nuclear Information System (INIS)

    Polfus, Jonathan M.; Norby, Truls; Haugsrud, Reidar

    2013-01-01

    Incorporation of nitrogen into oxides has in recent years received increased attention as a variable for tuning their functional properties. A vast number of reports have been devoted to improving the photocatalytic properties of TiO 2 , p-type charge carrier concentration in ZnO and the ionic transport properties of ZrO 2 by nitrogen doping. In comparison, the fundamentals of the nitrogen related defect chemistry for a wider range of oxides have been less focused upon. In the present contribution, we review experimental and computational investigations of the nitrogen related defect chemistry of insulating and semiconducting oxides. The interaction between nitrogen and protons is important and emphasized. Specifically, the stability of nitrogen defects such as N O / , NH O × and (NH 2 ) O • is evaluated under various conditions and their atomistic and electronic structure is presented. A final discussion is devoted to the role of nitrogen with respect to transport properties and photocatalytic activity of oxides. - Graphical abstract: Experimental and theoretical investigations of the nitrogen related defect chemistry of a range of wide band gap oxides is reviewed. The interaction between nitrogen dopants and protons is emphasized and described through the atomistic and electronic structure as well as defect chemical processes involving NH and NH 2 defects. Consequently, the physical properties of oxides containing such species are discussed with respect to e.g., diffusion and photocatalytic properties. Highlights: ► Experimental and theoretical investigations of the nitrogen and hydrogen related defect chemistry of wide band gap oxides is reviewed. ► The interaction between nitrogen dopants and protons is important and emphasized. ► Diffusion and photocatalytic properties of N-doped oxides are discussed.

  8. Experimental Investigation of Turbulence-Chemistry Interaction in High-Reynolds-Number Turbulent Partially Premixed Flames

    Science.gov (United States)

    2016-06-23

    AFRL-AFOSR-VA-TR-2016-0277 Experimental Investigation of Turbulence-Chemistry Interaction in High- Reynolds -Number Turbulent Partially Premixed...4. TITLE AND SUBTITLE [U] Experimental investigation of turbulence-chemistry interaction in high- Reynolds -number 5a. CONTRACT NUMBER turbulent...for public release Final Report: Experimental investigation of turbulence-chemistry interaction in high- Reynolds -number turbulent partially premixed

  9. Computational Chemistry Capacity Building in an Underprivileged ...

    African Journals Online (AJOL)

    Bridging the gap with the other continents requires the identification of capacity ... university in South Africa), where computational chemistry research capacity has ... testifies the feasibility of such capacity building also in conditions of limited ...

  10. Minicomputer and computations in chemistry

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    The introduction of multiple-precision hardware and longer word lengths has given the minicomputer a much more general potential for chemistry applications. It was the purpose of this workshop to address this potential, particularly as it is related to computations. The workshop brought together persons with minicomputer experience and those who are considering how the minicomputer might enhance their research activities. The workshop sessions were arranged in sequence to address the following questions: (1) Is the general purpose minicomputer an appropriate tool to meet the computational requirements of a chemistry research laboratory. (2) What are the procedures for wisely designing a minicomputer configuration. (3) What special-purpose hardware is available to enhance the speed of a minicomputer. (4) How does one select the appropriate minicomputer and ensure that it can accomplish the tasks for which is was designed. (5) How can one network minicomputers for more efficient and flexible operation. (6) Can one do really large-scale computations on a minicomputer and what modifications are necessary to convert existing programs and algorithms. (7) How can the minicomputer be used to access the maxicomputers at the NRCC. (8) How are computers likely to evolve in the future. (9) What should be the role of the NRCC in relation to minicomputers. This report of the workshop consists mainly of edited transcripts of introductory remarks. These were augmented by relevant bibliographies as an alternative to transcription of the entire workshop. There was no attempt in the workshop to give final answers to the questions that were raised, since the answers are determined in large part by each particular minicomputer environment.

  11. Experimental interstellar organic chemistry - Preliminary findings

    Science.gov (United States)

    Khare, B. N.; Sagan, C.

    1973-01-01

    Review of the results of some explicit experimental simulation of interstellar organic chemistry consisting in low-temperature high-vacuum UV irradiation of condensed simple gases known or suspected to be present in the interstellar medium. The results include the finding that acetonitrile may be present in the interstellar medium. The implication of this and other findings are discussed.

  12. The chemistry of transactinide elements. Experimental achievements and perspectives

    International Nuclear Information System (INIS)

    Schaedel, M.

    2002-01-01

    The chemistry of transactinides and superheavy elements has reached element 108. Preparations are under way to leap to element 112 and beyond. This development, its current status and future perspectives are reviewed from an experimental point of view. The atom-at-a-time situation of transactinide chemistry is briefly outlines. Experimental techniques and important results enlightening the chemical properties of elements 104 through 108 are presented in an exemplary way with emphasis on the aqueous chemistry of the lighter ones. From the results of these experiments it is justified to place these elements in the Periodic Table of the Elements into groups 4 through 8, respectively. However, strongly due to the influence of relativistic effects, it is no longer possible to deduce detailed chemical properties of these superheavy elements from this position. Perspectives for future research programs are given. (author)

  13. An Open Source Computational Framework for Uncertainty Quantification of Plasma Chemistry Models

    OpenAIRE

    Zaheri Sarabi, Shadi

    2017-01-01

    The current thesis deals with the development of a computational framework for performing plasma chemistry simulations and their uncertainty quantification analysis by suitably combining and extending existing open source computational tools. A plasma chemistry solver is implemented in the OpenFOAM C++ solver suite. The OpenFOAM plasma chemistry application solves the species conservation equations and the electron energy equation by accounting suitably for various production and loss terms b...

  14. Computer-based, Jeopardy™-like game in general chemistry for engineering majors

    Science.gov (United States)

    Ling, S. S.; Saffre, F.; Kadadha, M.; Gater, D. L.; Isakovic, A. F.

    2013-03-01

    We report on the design of Jeopardy™-like computer game for enhancement of learning of general chemistry for engineering majors. While we examine several parameters of student achievement and attitude, our primary concern is addressing the motivation of students, which tends to be low in a traditionally run chemistry lectures. The effect of the game-playing is tested by comparing paper-based game quiz, which constitutes a control group, and computer-based game quiz, constituting a treatment group. Computer-based game quizzes are Java™-based applications that students run once a week in the second part of the last lecture of the week. Overall effectiveness of the semester-long program is measured through pretest-postest conceptual testing of general chemistry. The objective of this research is to determine to what extent this ``gamification'' of the course delivery and course evaluation processes may be beneficial to the undergraduates' learning of science in general, and chemistry in particular. We present data addressing gender-specific difference in performance, as well as background (pre-college) level of general science and chemistry preparation. We outline the plan how to extend such approach to general physics courses and to modern science driven electives, and we offer live, in-lectures examples of our computer gaming experience. We acknowledge support from Khalifa University, Abu Dhabi

  15. [Advancements of computer chemistry in separation of Chinese medicine].

    Science.gov (United States)

    Li, Lingjuan; Hong, Hong; Xu, Xuesong; Guo, Liwei

    2011-12-01

    Separating technique of Chinese medicine is not only a key technique in the field of Chinese medicine' s research and development, but also a significant step in the modernization of Chinese medicinal preparation. Computer chemistry can build model and look for the regulations from Chinese medicine system which is full of complicated data. This paper analyzed the applicability, key technology, basic mode and common algorithm of computer chemistry applied in the separation of Chinese medicine, introduced the mathematic mode and the setting methods of Extraction kinetics, investigated several problems which based on traditional Chinese medicine membrane procession, and forecasted the application prospect.

  16. Improve Outcomes Study subjects Chemistry Teaching and Learning Strategies through independent study with the help of computer-based media

    Science.gov (United States)

    Sugiharti, Gulmah

    2018-03-01

    This study aims to see the improvement of student learning outcomes by independent learning using computer-based learning media in the course of STBM (Teaching and Learning Strategy) Chemistry. Population in this research all student of class of 2014 which take subject STBM Chemistry as many as 4 class. While the sample is taken by purposive as many as 2 classes, each 32 students, as control class and expriment class. The instrument used is the test of learning outcomes in the form of multiple choice with the number of questions as many as 20 questions that have been declared valid, and reliable. Data analysis techniques used one-sided t test and improved learning outcomes using a normalized gain test. Based on the learning result data, the average of normalized gain values for the experimental class is 0,530 and for the control class is 0,224. The result of the experimental student learning result is 53% and the control class is 22,4%. Hypothesis testing results obtained t count> ttable is 9.02> 1.6723 at the level of significance α = 0.05 and db = 58. This means that the acceptance of Ha is the use of computer-based learning media (CAI Computer) can improve student learning outcomes in the course Learning Teaching Strategy (STBM) Chemistry academic year 2017/2018.

  17. Computational Study of Nonequilibrium Chemistry in High Temperature Flows

    Science.gov (United States)

    Doraiswamy, Sriram

    Recent experimental measurements in the reflected shock tunnel CUBRC LENS-I facility raise questions about our ability to correctly model the recombination processes in high enthalpy flows. In the carbon dioxide flow, the computed shock standoff distance over the Mars Science Laboratory (MSL) shape was less than half of the experimental result. For the oxygen flows, both pressure and heat transfer data on the double cone geometry were not correctly predicted. The objective of this work is to investigate possible reasons for these discrepancies. This process involves systematically addressing different factors that could possibly explain the differences. These factors include vibrational modeling, role of electronic states and chemistry-vibrational coupling in high enthalpy flows. A state-specific vibrational model for CO2, CO, O2 and O system is devised by taking into account the first few vibrational states of each species. All vibrational states with energies at or below 1 eV are included in the present work. Of the three modes of vibration in CO2 , the antisymmetric mode is considered separately from the symmetric stretching mode and the doubly degenerate bending modes. The symmetric and the bending modes are grouped together since the energy transfer rates between the two modes are very large due to Fermi resonance. The symmetric and bending modes are assumed to be in equilibrium with the translational and rotational modes. The kinetic rates for the vibrational-translation energy exchange reactions, and the intermolecular and intramolecular vibrational-vibrational energy exchange reactions are based on experimental data to the maximum extent possible. Extrapolation methods are employed when necessary. This vibrational model is then coupled with an axisymmetric computational fluid dynamics code to study the expansion of CO2 in a nozzle. The potential role of low lying electronic states is also investigated. Carbon dioxide has a single excited state just below

  18. Development and Assessment of a Chemistry-Based Computer Video Game as a Learning Tool

    Science.gov (United States)

    Martinez-Hernandez, Kermin Joel

    2010-01-01

    The chemistry-based computer video game is a multidisciplinary collaboration between chemistry and computer graphics and technology fields developed to explore the use of video games as a possible learning tool. This innovative approach aims to integrate elements of commercial video game and authentic chemistry context environments into a learning…

  19. Combinatorial computational chemistry approach to the design of metal catalysts for deNOx

    International Nuclear Information System (INIS)

    Endou, Akira; Jung, Changho; Kusagaya, Tomonori; Kubo, Momoji; Selvam, Parasuraman; Miyamoto, Akira

    2004-01-01

    Combinatorial chemistry is an efficient technique for the synthesis and screening of a large number of compounds. Recently, we introduced the combinatorial approach to computational chemistry for catalyst design and proposed a new method called ''combinatorial computational chemistry''. In the present study, we have applied this combinatorial computational chemistry approach to the design of precious metal catalysts for deNO x . As the first step of the screening of the metal catalysts, we studied Rh, Pd, Ag, Ir, Pt, and Au clusters regarding the adsorption properties towards NO molecule. It was demonstrated that the energetically most stable adsorption state of NO on Ir model cluster, which was irrespective of both the shape and number of atoms including the model clusters

  20. Laboratory Sequence in Computational Methods for Introductory Chemistry

    Science.gov (United States)

    Cody, Jason A.; Wiser, Dawn C.

    2003-07-01

    A four-exercise laboratory sequence for introductory chemistry integrating hands-on, student-centered experience with computer modeling has been designed and implemented. The progression builds from exploration of molecular shapes to intermolecular forces and the impact of those forces on chemical separations made with gas chromatography and distillation. The sequence ends with an exploration of molecular orbitals. The students use the computers as a tool; they build the molecules, submit the calculations, and interpret the results. Because of the construction of the sequence and its placement spanning the semester break, good laboratory notebook practices are reinforced and the continuity of course content and methods between semesters is emphasized. The inclusion of these techniques in the first year of chemistry has had a positive impact on student perceptions and student learning.

  1. Handbook of computational quantum chemistry

    CERN Document Server

    Cook, David B

    2005-01-01

    Quantum chemistry forms the basis of molecular modeling, a tool widely used to obtain important chemical information and visual images of molecular systems. Recent advances in computing have resulted in considerable developments in molecular modeling, and these developments have led to significant achievements in the design and synthesis of drugs and catalysts. This comprehensive text provides upper-level undergraduates and graduate students with an introduction to the implementation of quantum ideas in molecular modeling, exploring practical applications alongside theoretical explanations.Wri

  2. Computational radiation chemistry: the emergence of a new field

    International Nuclear Information System (INIS)

    Bartczak, W.M.; Kroh, J.

    1991-01-01

    The role of the computer experiment as an information source, which is complementary to the ''real'' experiment in radiation chemistry, is discussed. The discussion is followed by a brief review of some of the simulation techniques, which have been recently applied to the problems of radiation chemistry: ion recombination in spurs and tracks of ionization, electron tunnelling in low-temperature glasses, electron localization in disordered media. (author)

  3. Computationally efficient implementation of combustion chemistry in parallel PDF calculations

    International Nuclear Information System (INIS)

    Lu Liuyan; Lantz, Steven R.; Ren Zhuyin; Pope, Stephen B.

    2009-01-01

    In parallel calculations of combustion processes with realistic chemistry, the serial in situ adaptive tabulation (ISAT) algorithm [S.B. Pope, Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation, Combustion Theory and Modelling, 1 (1997) 41-63; L. Lu, S.B. Pope, An improved algorithm for in situ adaptive tabulation, Journal of Computational Physics 228 (2009) 361-386] substantially speeds up the chemistry calculations on each processor. To improve the parallel efficiency of large ensembles of such calculations in parallel computations, in this work, the ISAT algorithm is extended to the multi-processor environment, with the aim of minimizing the wall clock time required for the whole ensemble. Parallel ISAT strategies are developed by combining the existing serial ISAT algorithm with different distribution strategies, namely purely local processing (PLP), uniformly random distribution (URAN), and preferential distribution (PREF). The distribution strategies enable the queued load redistribution of chemistry calculations among processors using message passing. They are implemented in the software x2f m pi, which is a Fortran 95 library for facilitating many parallel evaluations of a general vector function. The relative performance of the parallel ISAT strategies is investigated in different computational regimes via the PDF calculations of multiple partially stirred reactors burning methane/air mixtures. The results show that the performance of ISAT with a fixed distribution strategy strongly depends on certain computational regimes, based on how much memory is available and how much overlap exists between tabulated information on different processors. No one fixed strategy consistently achieves good performance in all the regimes. Therefore, an adaptive distribution strategy, which blends PLP, URAN and PREF, is devised and implemented. It yields consistently good performance in all regimes. In the adaptive parallel

  4. Computational Materials Science and Chemistry: Accelerating Discovery and Innovation through Simulation-Based Engineering and Science

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, George [Argonne National Lab. (ANL), Argonne, IL (United States); Glotzer, Sharon [University of Michigan; McCurdy, Bill [University of California Davis; Roberto, Jim [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2010-07-26

    abating, has enabled the development of computer simulations and models of unprecedented fidelity. We are at the threshold of a new era where the integrated synthesis, characterization, and modeling of complex materials and chemical processes will transform our ability to understand and design new materials and chemistries with predictive power. In turn, this predictive capability will transform technological innovation by accelerating the development and deployment of new materials and processes in products and manufacturing. Harnessing the potential of computational science and engineering for the discovery and development of materials and chemical processes is essential to maintaining leadership in these foundational fields that underpin energy technologies and industrial competitiveness. Capitalizing on the opportunities presented by simulation-based engineering and science in materials and chemistry will require an integration of experimental capabilities with theoretical and computational modeling; the development of a robust and sustainable infrastructure to support the development and deployment of advanced computational models; and the assembly of a community of scientists and engineers to implement this integration and infrastructure. This community must extend to industry, where incorporating predictive materials science and chemistry into design tools can accelerate the product development cycle and drive economic competitiveness. The confluence of new theories, new materials synthesis capabilities, and new computer platforms has created an unprecedented opportunity to implement a "materials-by-design" paradigm with wide-ranging benefits in technological innovation and scientific discovery. The Workshop on Computational Materials Science and Chemistry for Innovation was convened in Bethesda, Maryland, on July 26-27, 2010. Sponsored by the Department of Energy (DOE) Offices of Advanced Scientific Computing Research and Basic Energy Sciences, the workshop

  5. Theoretical Hammett Plot for the Gas-Phase Ionization of Benzoic Acid versus Phenol: A Computational Chemistry Lab Exercise

    Science.gov (United States)

    Ziegler, Blake E.

    2013-01-01

    Computational chemistry undergraduate laboratory courses are now part of the chemistry curriculum at many universities. However, there remains a lack of computational chemistry exercises available to instructors. This exercise is presented for students to develop skills using computational chemistry software while supplementing their knowledge of…

  6. Advances in computational actinide chemistry in China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqi; Wu, Jingyi; Chai, Zhifang [Chinese Academy of Sciences, Beijing (China). Multidisciplinary Initiative Center; Su, Jing [Chinese Academy of Sciences, Shanghai (China). Div. of Nuclear Materials Science and Engineering; Li, Jun [Tsinghua Univ., Beijing (China). Dept. of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering

    2014-04-01

    The advances in computational actinide chemistry made in China are reviewed. Several areas relevant to chemistry of actinides in gas, liquid, and solid phases have been explored. However, we limit the scope to selected contributions in the chemistry of molecular actinide systems in gas and liquid phases. These studies may be classified into two categories: treatment of relativistic effects, which cover the development of two- and four-component Hamiltonians and the optimization of relativistic pseudopotentials, and the applications of theoretical methods in actinide chemistry. The applications include (1) the electronic structures of actinocene, noble gas complexes, An-C multiple bonding compounds, uranyl and its isoelectronic species, fluorides and oxides, molecular systems with metal-metal bonding in their isolated forms (U{sub 2}, Pu{sub 2}) and in fullerene (U{sub 2} rate at C{sub 60}), and the excited states of actinide complexes; (2) chemical reactions, including oxidation, hydrolysis of UF{sub 6}, ligand exchange, reactivities of thorium oxo and sulfido metallocenes, CO{sub 2}/CS{sub 2} functionalization promoted by trivalent uranium complex; and (3) migration of actinides in the environment. A future outlook is discussed. (orig.)

  7. The Effectiveness of a Computer-Assisted Instruction Package in Supplementing Teaching of Selected Concepts in High School Chemistry: Writing Formulas and Balancing Chemical Equations.

    Science.gov (United States)

    Wainwright, Camille L.

    Four classes of high school chemistry students (N=108) were randomly assigned to experimental and control groups to investigate the effectiveness of a computer assisted instruction (CAI) package during a unit on writing/naming of chemical formulas and balancing equations. Students in the experimental group received drill, review, and reinforcement…

  8. Artificial Intelligence Support for Computational Chemistry

    Science.gov (United States)

    Duch, Wlodzislaw

    Possible forms of artificial intelligence (AI) support for quantum chemistry are discussed. Questions addressed include: what kind of support is desirable, what kind of support is feasible, what can we expect in the coming years. Advantages and disadvantages of current AI techniques are presented and it is argued that at present the memory-based systems are the most effective for large scale applications. Such systems may be used to predict the accuracy of calculations and to select the least expensive methods and basis sets belonging to the same accuracy class. Advantages of the Feature Space Mapping as an improvement on the memory based systems are outlined and some results obtained in classification problems given. Relevance of such classification systems to computational chemistry is illustrated with two examples showing similarity of results obtained by different methods that take electron correlation into account.

  9. Computational Exploration of Molecular Scaffolds in Medicinal Chemistry.

    Science.gov (United States)

    Hu, Ye; Stumpfe, Dagmar; Bajorath, Jürgen

    2016-05-12

    The scaffold concept is widely applied in medicinal chemistry. Scaffolds are mostly used to represent core structures of bioactive compounds. Although the scaffold concept has limitations and is often viewed differently from a chemical and computational perspective, it has provided a basis for systematic investigations of molecular cores and building blocks, going far beyond the consideration of individual compound series. Over the past 2 decades, alternative scaffold definitions and organization schemes have been introduced and scaffolds have been studied in a variety of ways and increasingly on a large scale. Major applications of the scaffold concept include the generation of molecular hierarchies, structural classification, association of scaffolds with biological activities, and activity prediction. This contribution discusses computational approaches for scaffold generation and analysis, with emphasis on recent developments impacting medicinal chemistry. A variety of scaffold-based studies are discussed, and a perspective on scaffold methods is provided.

  10. Computational Tools To Model Halogen Bonds in Medicinal Chemistry.

    Science.gov (United States)

    Ford, Melissa Coates; Ho, P Shing

    2016-03-10

    The use of halogens in therapeutics dates back to the earliest days of medicine when seaweed was used as a source of iodine to treat goiters. The incorporation of halogens to improve the potency of drugs is now fairly standard in medicinal chemistry. In the past decade, halogens have been recognized as direct participants in defining the affinity of inhibitors through a noncovalent interaction called the halogen bond or X-bond. Incorporating X-bonding into structure-based drug design requires computational models for the anisotropic distribution of charge and the nonspherical shape of halogens, which lead to their highly directional geometries and stabilizing energies. We review here current successes and challenges in developing computational methods to introduce X-bonding into lead compound discovery and optimization during drug development. This fast-growing field will push further development of more accurate and efficient computational tools to accelerate the exploitation of halogens in medicinal chemistry.

  11. Physical chemistry and the environment

    International Nuclear Information System (INIS)

    Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

    1994-08-01

    From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ''Physical Chemistry and the Environment'' was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community

  12. Promoting Intrinsic and Extrinsic Motivation among Chemistry Students Using Computer-Assisted Instruction

    Science.gov (United States)

    Gambari, Isiaka A.; Gbodi, Bimpe E.; Olakanmi, Eyitao U.; Abalaka, Eneojo N.

    2016-01-01

    The role of computer-assisted instruction in promoting intrinsic and extrinsic motivation among Nigerian secondary school chemistry students was investigated in this study. The study employed two modes of computer-assisted instruction (computer simulation instruction and computer tutorial instructional packages) and two levels of gender (male and…

  13. Benchmarking Experimental and Computational Thermochemical Data: A Case Study of the Butane Conformers.

    Science.gov (United States)

    Barna, Dóra; Nagy, Balázs; Csontos, József; Császár, Attila G; Tasi, Gyula

    2012-02-14

    Due to its crucial importance, numerous studies have been conducted to determine the enthalpy difference between the conformers of butane. However, it is shown here that the most reliable experimental values are biased due to the statistical model utilized during the evaluation of the raw experimental data. In this study, using the appropriate statistical model, both the experimental expectation values and the associated uncertainties are revised. For the 133-196 and 223-297 K temperature ranges, 668 ± 20 and 653 ± 125 cal mol(-1), respectively, are recommended as reference values. Furthermore, to show that present-day quantum chemistry is a favorable alternative to experimental techniques in the determination of enthalpy differences of conformers, a focal-point analysis, based on coupled-cluster electronic structure computations, has been performed that included contributions of up to perturbative quadruple excitations as well as small correction terms beyond the Born-Oppenheimer and nonrelativistic approximations. For the 133-196 and 223-297 K temperature ranges, in exceptional agreement with the corresponding revised experimental data, our computations yielded 668 ± 3 and 650 ± 6 cal mol(-1), respectively. The most reliable enthalpy difference values for 0 and 298.15 K are also provided by the computational approach, 680.9 ± 2.5 and 647.4 ± 7.0 cal mol(-1), respectively.

  14. Computational organic chemistry: bridging theory and experiment in establishing the mechanisms of chemical reactions.

    Science.gov (United States)

    Cheng, Gui-Juan; Zhang, Xinhao; Chung, Lung Wa; Xu, Liping; Wu, Yun-Dong

    2015-02-11

    Understanding the mechanisms of chemical reactions, especially catalysis, has been an important and active area of computational organic chemistry, and close collaborations between experimentalists and theorists represent a growing trend. This Perspective provides examples of such productive collaborations. The understanding of various reaction mechanisms and the insight gained from these studies are emphasized. The applications of various experimental techniques in elucidation of reaction details as well as the development of various computational techniques to meet the demand of emerging synthetic methods, e.g., C-H activation, organocatalysis, and single electron transfer, are presented along with some conventional developments of mechanistic aspects. Examples of applications are selected to demonstrate the advantages and limitations of these techniques. Some challenges in the mechanistic studies and predictions of reactions are also analyzed.

  15. Interactive Computer Visualization in the Introductory Chemistry Curriculum

    Science.gov (United States)

    Bragin, Victoria M.

    1996-08-01

    related applications such as one on VSEPR. Computer-fitting of smooth curves to experimental data was a new experience for many students. In the second semester general chemistry course, students determined the equivalence points from the first derivative of a curve fit to their experimental measurements. Points of inflection, maxima, minima, and other mathematical parameters now had a real meaning in terms of observable properties of the physical systems being studied, and many students voiced satisfaction in applying what they had learned in mathematics classes to analyzing data collected in the science laboratory. A commercial spreadsheet with a scripting language is used for data analysis. Students enter their experimental data and calculated results. The script indicates if their result is correct within reasonable limits of error but does not perform the calculations for them. Most students opt to use this application even though it is not required. A bulletin board system (ChemistryBBS) with a graphical user interface has been created in which students post questions on course material and other students or faculty post answers or suggestions. ChemistryBBS encourages participation by those who do not speak up in class as well as by those whose spoken English is imperfect. Students use e-mail to hand in homework and laboratory reports. They particularly enjoy the ease with which graphics can be incorporated into text documents, and many students produce professional looking reports. Other courseware in various stages of development include Dimensions (dimensional analysis), MindYourSigFigs (use of significant figures in measurements), What'sInAName (inorganic nomenclature), PeriodicTable (an interactive handbook of periodic properties of the elements), RedoxReactions, ElectrochemicalCells, and Carbon-13NMR. A commercial application that captures screen images and sound is used to develop custom lesson modules adapted to the learning styles of individual students and

  16. Integrating Free Computer Software in Chemistry and Biochemistry Instruction: An International Collaboration

    Science.gov (United States)

    Cedeno, David L.; Jones, Marjorie A.; Friesen, Jon A.; Wirtz, Mark W.; Rios, Luz Amalia; Ocampo, Gonzalo Taborda

    2010-01-01

    At the Universidad de Caldas, Manizales, Colombia, we used their new computer facilities to introduce chemistry graduate students to biochemical database mining and quantum chemistry calculations using freeware. These hands-on workshops allowed the students a strong introduction to easily accessible software and how to use this software to begin…

  17. Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

    Science.gov (United States)

    Sander, Stanley P.; Friedl, Randall R.

    1993-01-01

    Over the last five years substantial progress has been made in defining the realm of new chlorine chemistry in the polar stratosphere. Application of existing experimental techniques to potentially important chlorine-containing compounds has yielded quantitative kinetic and spectroscopic data as well as qualitative mechanistic insights into the relevant reactions.

  18. Development of tight-binding, chemical-reaction-dynamics simulator for combinatorial computational chemistry

    International Nuclear Information System (INIS)

    Kubo, Momoji; Ando, Minako; Sakahara, Satoshi; Jung, Changho; Seki, Kotaro; Kusagaya, Tomonori; Endou, Akira; Takami, Seiichi; Imamura, Akira; Miyamoto, Akira

    2004-01-01

    Recently, we have proposed a new concept called 'combinatorial computational chemistry' to realize a theoretical, high-throughput screening of catalysts and materials. We have already applied our combinatorial, computational-chemistry approach, mainly based on static first-principles calculations, to various catalysts and materials systems and its applicability to the catalysts and materials design was strongly confirmed. In order to realize more effective and efficient combinatorial, computational-chemistry screening, a high-speed, chemical-reaction-dynamics simulator based on quantum-chemical, molecular-dynamics method is essential. However, to the best of our knowledge, there is no chemical-reaction-dynamics simulator, which has an enough high-speed ability to perform a high-throughput screening. In the present study, we have succeeded in the development of a chemical-reaction-dynamics simulator based on our original, tight-binding, quantum-chemical, molecular-dynamics method, which is more than 5000 times faster than the regular first-principles, molecular-dynamics method. Moreover, its applicability and effectiveness to the atomistic clarification of the methanol-synthesis dynamics at reaction temperature were demonstrated

  19. E.C.C.C.1 Computational Chemistry: F.E.C.S. Conference. Proceedings

    International Nuclear Information System (INIS)

    Bernardi, F.; Rivail, J.; Cernusak, I.; Gasteiger, J.; Robb, M.; Soulie, E.; Troyanowsky, C.; Varmuza, K.

    1995-01-01

    These proceedings represent the papers presented at the First European Conference on Computational Chemistry held in Nancy, France. The papers presented fall into three groups:1. Methods and applications of quantum molecular modeling, 2. Classical molecular modeling, 3. Methods and applications in the treatment of chemical information. The papers represent a fair and balanced survey of the present trends of European research in computational chemistry. There were 237 papers presented and 10 have been abstracted for the Energy Science and Technology database

  20. Experimental and Analytical Studies of Solar System Chemistry

    Science.gov (United States)

    Burnett, Donald S.

    2003-01-01

    The cosmochemistry research funded by this grant resulted in the publications given in the attached Publication List. The research focused in three areas: (1) Experimental studies of trace element partitioning. (2) Studies of the minor element chemistry and O isotopic compositions of MgAlO4 spinels from Ca-Al-Rich Inclusions in carbonaceous chondrite meteorites, and (3) The abundances and chemical fractionations of Th and U in chondritic meteorites.

  1. Investigating the Effectiveness of Computer Simulations for Chemistry Learning

    Science.gov (United States)

    Plass, Jan L.; Milne, Catherine; Homer, Bruce D.; Schwartz, Ruth N.; Hayward, Elizabeth O.; Jordan, Trace; Verkuilen, Jay; Ng, Florrie; Wang, Yan; Barrientos, Juan

    2012-01-01

    Are well-designed computer simulations an effective tool to support student understanding of complex concepts in chemistry when integrated into high school science classrooms? We investigated scaling up the use of a sequence of simulations of kinetic molecular theory and associated topics of diffusion, gas laws, and phase change, which we designed…

  2. Students' Hands-on Experimental Work vs Lecture Demonstration in Teaching Elementary School Chemistry.

    Science.gov (United States)

    Logar, Ana; Ferk-Savec, Vesna

    2011-12-01

    Science educators have suggested many benefits that accrue from engaging students in experimental activities, therefore, experimental work has a long and distinctive role in chemistry curriculum since. The presented empirical study focuses on the valuation of effectiveness of different forms of experimental work - students' hands-on experimental work vs teacher's lecture demonstration - from the viewpoint of the quality of content knowledge acquisition and knowledge retention in teaching primary school chemistry. 106 primary school students (age 14-15 years) participated in the study. The data was collected via pre- and post- test protocol and two delayed post tests. Additionally 16 students selected from the sample were interviewed. The results indicate that students' content knowledge gained through teacher's demonstration of experiment is better and better knowledge retention takes place in comparison to students' knowledge gained through students' hands-on experimental work. However, most of the inteviewed students stated that they prefered conducting of experiments by themselves in comparison to observation of teacher's demonstration.

  3. Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications

    International Nuclear Information System (INIS)

    Allain, J.P.; Rokusek, D.L.; Harilal, S.S.; Nieto-Perez, M.; Skinner, C.H.; Kugel, H.W.; Heim, B.; Kaita, R.; Majeski, R.

    2009-01-01

    Lithium has enhanced the operational performance of fusion devices such as: TFTR, CDX-U, FTU, T-11 M, and NSTX. Lithium in the solid and liquid state has been studied extensively in laboratory experiments including its erosion and hydrogen-retaining properties. Reductions in physical sputtering up to 40-60% have been measured for deuterated solid and liquid lithium surfaces. Computational modeling indicates that up to a 1:1 deuterium volumetric retention in lithium is possible. This paper presents the results of systematic in situ laboratory experimental studies on the surface chemistry evolution of ATJ graphite under lithium deposition. Results are compared to post-mortem analysis of similar lithium surface coatings on graphite exposed to deuterium discharge plasmas in NSTX. Lithium coatings on plasma-facing components in NSTX have shown substantial reduction of hydrogenic recycling. Questions remain on the role lithium surface chemistry on a graphite substrate has on particle sputtering (physical and chemical) as well as hydrogen isotope recycling. This is particularly due to the lack of in situ measurements of plasma-surface interactions in tokamaks such as NSTX. Results suggest that the lithium bonding state on ATJ graphite is lithium peroxide and with sufficient exposure to ambient air conditions, lithium carbonate is generated. Correlation between both results is used to assess the role of lithium chemistry on the state of lithium bonding and implications on hydrogen pumping and lithium sputtering. In addition, reduction of factors between 10 and 30 reduction in physical sputtering from lithiated graphite compared to pure lithium or carbon is also measured.

  4. Combustion chemistry of alcohols: Experimental and modeled structure of a premixed 2-methylbutanol flame

    KAUST Repository

    Lucassen, Arnas; Park, Sungwoo; Hansen, Nils; Sarathy, Mani

    2014-01-01

    This paper presents a detailed investigation of 2-methylbutanol combustion chemistry in low-pressure premixed flames. This chemistry is of particular interest to study because this compound is potentially a lignocellulosic-based, next-generation biofuel. The detailed chemical structure of a stoichiometric low-pressure (25 Torr) flame was determined using flame-sampling molecular-beam mass spectrometry. A total of 55 species were identified and subsequently quantitative mole fraction profiles as function of distance from the burner surface were determined. In an independent effort, a detailed flame chemistry model for 2-methylbutanol was assembled based on recent knowledge gained from combustion chemistry studies for butanol isomers ([Sarathy et al. Combust. Flame 159 (6) (2012) 2028-2055]) and iso-pentanol (3-methylbutanol) [Sarathy et al. Combust. Flame 160 (12) (2013) 2712-2728]. Experimentally determined and modeled mole fraction profiles were compared to demonstrate the model's capabilities. Examples of individual mole fraction profiles are discussed together with the most significant fuel consumption pathways to highlight the combustion chemistry of 2-methylbutanol. Discrepancies between experimental and modeling results are used to suggest areas where improvement of the kinetic model would be needed. © 2014.

  5. Combustion chemistry of alcohols: Experimental and modeled structure of a premixed 2-methylbutanol flame

    KAUST Repository

    Lucassen, Arnas

    2014-06-14

    This paper presents a detailed investigation of 2-methylbutanol combustion chemistry in low-pressure premixed flames. This chemistry is of particular interest to study because this compound is potentially a lignocellulosic-based, next-generation biofuel. The detailed chemical structure of a stoichiometric low-pressure (25 Torr) flame was determined using flame-sampling molecular-beam mass spectrometry. A total of 55 species were identified and subsequently quantitative mole fraction profiles as function of distance from the burner surface were determined. In an independent effort, a detailed flame chemistry model for 2-methylbutanol was assembled based on recent knowledge gained from combustion chemistry studies for butanol isomers ([Sarathy et al. Combust. Flame 159 (6) (2012) 2028-2055]) and iso-pentanol (3-methylbutanol) [Sarathy et al. Combust. Flame 160 (12) (2013) 2712-2728]. Experimentally determined and modeled mole fraction profiles were compared to demonstrate the model\\'s capabilities. Examples of individual mole fraction profiles are discussed together with the most significant fuel consumption pathways to highlight the combustion chemistry of 2-methylbutanol. Discrepancies between experimental and modeling results are used to suggest areas where improvement of the kinetic model would be needed. © 2014.

  6. Química geral experimental: uma nova abordagem didática Experimental general chemistry: a new teaching approach

    Directory of Open Access Journals (Sweden)

    Geraldo Eduardo da Luz Júnior

    2004-02-01

    Full Text Available This essay describes a new didactic approach, in according with the national curriculum guidelines for chemistry undergraduate courses in Brazil, employed during the one-semester course "Experimental General Chemistry" for chemistry undergraduate students at the Federal University of Piauí. The new approach has positively helped student's training by improving their reading skills and their understanding of scientific reports, by developing the use of electronic tools to search and to recover the required knowledge for their learning activities, and by improving their skills of understanding published texts and dealing with digital sources. At the same time the students are strongly stimulated to enter the research program for undergraduate students available at the University.

  7. Computations for a condenser. Experimental results

    International Nuclear Information System (INIS)

    Walden, Jean.

    1975-01-01

    Computations for condensers are presented with experimental results. The computations are concerned with the steam flux at the condenser input, and inside the tube bundle. Experimental results are given for the flux inside the condenser sleeve and the flow passing through the tube bundle [fr

  8. Multi-scale multi-physics computational chemistry simulation based on ultra-accelerated quantum chemical molecular dynamics method for structural materials in boiling water reactor

    International Nuclear Information System (INIS)

    Miyamoto, Akira; Sato, Etsuko; Sato, Ryo; Inaba, Kenji; Hatakeyama, Nozomu

    2014-01-01

    In collaboration with experimental experts we have reported in the present conference (Hatakeyama, N. et al., “Experiment-integrated multi-scale, multi-physics computational chemistry simulation applied to corrosion behaviour of BWR structural materials”) the results of multi-scale multi-physics computational chemistry simulations applied to the corrosion behaviour of BWR structural materials. In macro-scale, a macroscopic simulator of anode polarization curve was developed to solve the spatially one-dimensional electrochemical equations on the material surface in continuum level in order to understand the corrosion behaviour of typical BWR structural material, SUS304. The experimental anode polarization behaviours of each pure metal were reproduced by fitting all the rates of electrochemical reactions and then the anode polarization curve of SUS304 was calculated by using the same parameters and found to reproduce the experimental behaviour successfully. In meso-scale, a kinetic Monte Carlo (KMC) simulator was applied to an actual-time simulation of the morphological corrosion behaviour under the influence of an applied voltage. In micro-scale, an ultra-accelerated quantum chemical molecular dynamics (UA-QCMD) code was applied to various metallic oxide surfaces of Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 modelled as same as water molecules and dissolved metallic ions on the surfaces, then the dissolution and segregation behaviours were successfully simulated dynamically by using UA-QCMD. In this paper we describe details of the multi-scale, multi-physics computational chemistry method especially the UA-QCMD method. This method is approximately 10,000,000 times faster than conventional first-principles molecular dynamics methods based on density-functional theory (DFT), and the accuracy was also validated for various metals and metal oxides compared with DFT results. To assure multi-scale multi-physics computational chemistry simulation based on the UA-QCMD method for

  9. Interactive computer modeling of combustion chemistry and coalescence-dispersion modeling of turbulent combustion

    Science.gov (United States)

    Pratt, D. T.

    1984-01-01

    An interactive computer code for simulation of a high-intensity turbulent combustor as a single point inhomogeneous stirred reactor was developed from an existing batch processing computer code CDPSR. The interactive CDPSR code was used as a guide for interpretation and direction of DOE-sponsored companion experiments utilizing Xenon tracer with optical laser diagnostic techniques to experimentally determine the appropriate mixing frequency, and for validation of CDPSR as a mixing-chemistry model for a laboratory jet-stirred reactor. The coalescence-dispersion model for finite rate mixing was incorporated into an existing interactive code AVCO-MARK I, to enable simulation of a combustor as a modular array of stirred flow and plug flow elements, each having a prescribed finite mixing frequency, or axial distribution of mixing frequency, as appropriate. Further increase the speed and reliability of the batch kinetics integrator code CREKID was increased by rewriting in vectorized form for execution on a vector or parallel processor, and by incorporating numerical techniques which enhance execution speed by permitting specification of a very low accuracy tolerance.

  10. Scalable Computational Chemistry: New Developments and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, Yuri [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    The computational part of the thesis is the investigation of titanium chloride (II) as a potential catalyst for the bis-silylation reaction of ethylene with hexaclorodisilane at different levels of theory. Bis-silylation is an important reaction for producing bis(silyl) compounds and new C-Si bonds, which can serve as monomers for silicon containing polymers and silicon carbides. Ab initio calculations on the steps involved in a proposed mechanism are presented. This choice of reactants allows them to study this reaction at reliable levels of theory without compromising accuracy. The calculations indicate that this is a highly exothermic barrierless reaction. The TiCl2 catalyst removes a 50 kcal/mol activation energy barrier required for the reaction without the catalyst. The first step is interaction of TiCl2 with ethylene to form an intermediate that is 60 kcal/mol below the energy of the reactants. This is the driving force for the entire reaction. Dynamic correlation plays a significant role because RHF calculations indicate that the net barrier for the catalyzed reaction is 50 kcal/mol. They conclude that divalent Ti has the potential to become an important industrial catalyst for silylation reactions. In the programming part of the thesis, parallelization of different quantum chemistry methods is presented. The parallelization of code is becoming important aspects of quantum chemistry code development. Two trends contribute to it: the overall desire to study large chemical systems and the desire to employ highly correlated methods which are usually computationally and memory expensive. In the presented distributed data algorithms computation is parallelized and the largest arrays are evenly distributed among CPUs. First, the parallelization of the Hartree-Fock self-consistent field (SCF) method is considered. SCF method is the most common starting point for more accurate calculations. The Fock build (sub step of SCF) from AO integrals is

  11. Experimental design in chemistry: A tutorial.

    Science.gov (United States)

    Leardi, Riccardo

    2009-10-12

    In this tutorial the main concepts and applications of experimental design in chemistry will be explained. Unfortunately, nowadays experimental design is not as known and applied as it should be, and many papers can be found in which the "optimization" of a procedure is performed one variable at a time. Goal of this paper is to show the real advantages in terms of reduced experimental effort and of increased quality of information that can be obtained if this approach is followed. To do that, three real examples will be shown. Rather than on the mathematical aspects, this paper will focus on the mental attitude required by experimental design. The readers being interested to deepen their knowledge of the mathematical and algorithmical part can find very good books and tutorials in the references [G.E.P. Box, W.G. Hunter, J.S. Hunter, Statistics for Experimenters: An Introduction to Design, Data Analysis, and Model Building, John Wiley & Sons, New York, 1978; R. Brereton, Chemometrics: Data Analysis for the Laboratory and Chemical Plant, John Wiley & Sons, New York, 1978; R. Carlson, J.E. Carlson, Design and Optimization in Organic Synthesis: Second Revised and Enlarged Edition, in: Data Handling in Science and Technology, vol. 24, Elsevier, Amsterdam, 2005; J.A. Cornell, Experiments with Mixtures: Designs, Models and the Analysis of Mixture Data, in: Series in Probability and Statistics, John Wiley & Sons, New York, 1991; R.E. Bruns, I.S. Scarminio, B. de Barros Neto, Statistical Design-Chemometrics, in: Data Handling in Science and Technology, vol. 25, Elsevier, Amsterdam, 2006; D.C. Montgomery, Design and Analysis of Experiments, 7th edition, John Wiley & Sons, Inc., 2009; T. Lundstedt, E. Seifert, L. Abramo, B. Thelin, A. Nyström, J. Pettersen, R. Bergman, Chemolab 42 (1998) 3; Y. Vander Heyden, LC-GC Europe 19 (9) (2006) 469].

  12. The use of computers for chemistry and corrosion monitoring in the nuclear power industry

    International Nuclear Information System (INIS)

    Eber, K.

    1986-01-01

    Corrosion of steam generators in the nuclear power industry has caused increasingly expensive maintenance work during refueling outages. To assist in the control and monitoring of this problem, Northeast Utilities has developed computer programs for tracking steam generator water chemistry and steam generator eddy current inspection data. These programs have allowed detailed analytical studies to be performed which would have been extremely difficult without the use of computers. The paper discusses the capabilities and uses of a chemistry data management system. An example analysis of steam generator chemistry during plant startup is presented. The corrosion monitoring capabilities of several eddy current data analysis programs are also discussed. It is demonstrated how these programs allow a detailed analysis of the effects of a chemical cleaning operation to remove sludge from the steam generators. Applications of these analytical methods to other industries is also discussed

  13. Chemometrics in analytical chemistry-part I: history, experimental design and data analysis tools.

    Science.gov (United States)

    Brereton, Richard G; Jansen, Jeroen; Lopes, João; Marini, Federico; Pomerantsev, Alexey; Rodionova, Oxana; Roger, Jean Michel; Walczak, Beata; Tauler, Romà

    2017-10-01

    Chemometrics has achieved major recognition and progress in the analytical chemistry field. In the first part of this tutorial, major achievements and contributions of chemometrics to some of the more important stages of the analytical process, like experimental design, sampling, and data analysis (including data pretreatment and fusion), are summarised. The tutorial is intended to give a general updated overview of the chemometrics field to further contribute to its dissemination and promotion in analytical chemistry.

  14. Biodiesel from soybean oil: experimental procedure of transesterification for organic chemistry laboratories

    International Nuclear Information System (INIS)

    Geris, Regina; Santos, Nadia Alessandra Carmo dos; Amaral, Bruno Andrade; Maia, Isabelle de Souza; Castro, Vinicius Dourado; Carvalho, Jose Roque Mota

    2007-01-01

    The transesterification procedure of triacylglycerides from soybean oil (in natura and waste oil) to give biodiesel was adapted to semi-micro laboratory scale as an additional experimental technique of nucleophilic acyl substitution for undergraduate courses in Chemistry and related areas. (author)

  15. [Animal experimentation, computer simulation and surgical research].

    Science.gov (United States)

    Carpentier, Alain

    2009-11-01

    We live in a digital world In medicine, computers are providing new tools for data collection, imaging, and treatment. During research and development of complex technologies and devices such as artificial hearts, computer simulation can provide more reliable information than experimentation on large animals. In these specific settings, animal experimentation should serve more to validate computer models of complex devices than to demonstrate their reliability.

  16. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    Science.gov (United States)

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  17. A Computer Algebra Approach to Solving Chemical Equilibria in General Chemistry

    Science.gov (United States)

    Kalainoff, Melinda; Lachance, Russ; Riegner, Dawn; Biaglow, Andrew

    2012-01-01

    In this article, we report on a semester-long study of the incorporation into our general chemistry course, of advanced algebraic and computer algebra techniques for solving chemical equilibrium problems. The method presented here is an alternative to the commonly used concentration table method for describing chemical equilibria in general…

  18. Experimental Mathematics and Computational Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.; Borwein, Jonathan M.

    2009-04-30

    The field of statistics has long been noted for techniques to detect patterns and regularities in numerical data. In this article we explore connections between statistics and the emerging field of 'experimental mathematics'. These includes both applications of experimental mathematics in statistics, as well as statistical methods applied to computational mathematics.

  19. Improving Students' Understanding of Molecular Structure through Broad-Based Use of Computer Models in the Undergraduate Organic Chemistry Lecture

    Science.gov (United States)

    Springer, Michael T.

    2014-01-01

    Several articles suggest how to incorporate computer models into the organic chemistry laboratory, but relatively few papers discuss how to incorporate these models broadly into the organic chemistry lecture. Previous research has suggested that "manipulating" physical or computer models enhances student understanding; this study…

  20. The use of computer-aided learning in chemistry laboratory instruction

    Science.gov (United States)

    Allred, Brian Robert Tracy

    This research involves developing and implementing computer software for chemistry laboratory instruction. The specific goal is to design the software and investigate whether it can be used to introduce concepts and laboratory procedures without a lecture format. This would allow students to conduct an experiment even though they may not have been introduced to the chemical concept in their lecture course. This would also allow for another type of interaction for those students who respond more positively to a visual approach to instruction. The first module developed was devoted to using computer software to help introduce students to the concepts related to thin-layer chromatography and setting up and running an experiment. This was achieved through the use of digitized pictures and digitized video clips along with written information. A review quiz was used to help reinforce the learned information. The second module was devoted to the concept of the "dry lab". This module presented students with relevant information regarding the chemical concepts and then showed them the outcome of mixing solutions. By these observations, they were to determine the composition of unknown solutions based on provided descriptions and comparison with their written observations. The third piece of the software designed was a computer game. This program followed the first two modules in providing information the students were to learn. The difference here, though, was incorporating a game scenario for students to use to help reinforce the learning. Students were then assessed to see how much information they retained after playing the game. In each of the three cases, a control group exposed to the traditional lecture format was used. Their results were compared to the experimental group using the computer modules. Based upon the findings, it can be concluded that using technology to aid in the instructional process is definitely of benefit and students were more successful in

  1. Computational chemistry with transputers: A direct SCF program

    International Nuclear Information System (INIS)

    Wedig, U.; Burkhardt, A.; Schnering, H.G. von

    1989-01-01

    By using transputers it is possible to build up networks of parallel processors with varying topology. Due to the architecture of the processors it is appropriate to use the MIMD (multiple instruction multiple data) concept of parallel computing. The most suitable programming language is OCCAM. We investigate the use of transputer networks in computational chemistry, starting with the direct SCF method. The most time consuming step, the calculation of the two electron integrals is executed parallelly. Each node in the network calculates whole batches of integrals. The main program is written in OCCAM. For some large-scale arithmetic processes running on a single node, however, we used FORTRAN subroutines out of standard ab-initio programs to reduce the programming effort. Test calculations show, that the integral calculation step can be parallelled very efficiently. We observed a speed-up of almost 8 using eight network processors. Even in consideration of the scalar part of the SCF iteration, the speed-up is not less than 7.1. (orig.)

  2. Computer-based system for inspection of water chemistry regimes in WWER-type nuclear power plants

    International Nuclear Information System (INIS)

    Burcl, R.; Novak, M.; Malenka, P.

    1993-01-01

    The unsatisfactory situation in water chemistry testing at nuclear power plants with WWER type reactors is described. The testing primarily relies on laboratory analyses of manually taken samples. About 40 samples from one unit are tested per shift, which comprises approximately 250 determinations of various parameters. The time between two determinations is no shorter than 4 to 6 hours, thus rapid parameter changes between two determinations fail to be monitored. A novel system of automated chemistry monitoring is outlined, feasible for WWER type reactors. The system comprises 10 sets of sensors for monitoring all the relevant chemistry parameters of both the primary and secondary coolant circuits. Each sensor set has its own autonomous computer which secures its function even in case of loss of the chemical information network. The entire system is controlled by a master computer which also collects the results and provides contact with the power plant's information system. (Z.S.). 1 fig

  3. Computational and Experimental Approaches to Visual Aesthetics

    Science.gov (United States)

    Brachmann, Anselm; Redies, Christoph

    2017-01-01

    Aesthetics has been the subject of long-standing debates by philosophers and psychologists alike. In psychology, it is generally agreed that aesthetic experience results from an interaction between perception, cognition, and emotion. By experimental means, this triad has been studied in the field of experimental aesthetics, which aims to gain a better understanding of how aesthetic experience relates to fundamental principles of human visual perception and brain processes. Recently, researchers in computer vision have also gained interest in the topic, giving rise to the field of computational aesthetics. With computing hardware and methodology developing at a high pace, the modeling of perceptually relevant aspect of aesthetic stimuli has a huge potential. In this review, we present an overview of recent developments in computational aesthetics and how they relate to experimental studies. In the first part, we cover topics such as the prediction of ratings, style and artist identification as well as computational methods in art history, such as the detection of influences among artists or forgeries. We also describe currently used computational algorithms, such as classifiers and deep neural networks. In the second part, we summarize results from the field of experimental aesthetics and cover several isolated image properties that are believed to have a effect on the aesthetic appeal of visual stimuli. Their relation to each other and to findings from computational aesthetics are discussed. Moreover, we compare the strategies in the two fields of research and suggest that both fields would greatly profit from a joined research effort. We hope to encourage researchers from both disciplines to work more closely together in order to understand visual aesthetics from an integrated point of view. PMID:29184491

  4. Microstructure and defect chemistry of yttrium aluminium garnet ceramics

    International Nuclear Information System (INIS)

    Schuh, L.H.

    1989-01-01

    This thesis describes basic aspects concerning the defect chemistry and the microstructure of yttrium aluminium garnet ceramics. The work consists of three parts: a literature study, an experimental part and a section giving computer simulation data of defects. (author). 320 refs.; 68 figs.; 72 schemes; 32 tabs

  5. Column chromatography with almecega resin: a project for experimental organic chemistry

    International Nuclear Information System (INIS)

    Vieira Junior, Gerardo Magela; Carvalho, Adonias Almeida; Gonzaga, Wellington de Abreu; Chaves, Mariana H.

    2007-01-01

    The use of natural products to demonstrate the silica gel column chromatography technique is proposed in the present article. It describes the separation of the triterpenes α- and β-amirin from the diol breine and maniladiol, obtained from almecega resin (Protium heptaphyllum March.). The experiment uses an accessible material, was accomplished in 4 h, and can be applied with success an the experimental course of organic chemistry for undergraduate students. (author)

  6. Current status and future prospects for enabling chemistry technology in the drug discovery process.

    Science.gov (United States)

    Djuric, Stevan W; Hutchins, Charles W; Talaty, Nari N

    2016-01-01

    This review covers recent advances in the implementation of enabling chemistry technologies into the drug discovery process. Areas covered include parallel synthesis chemistry, high-throughput experimentation, automated synthesis and purification methods, flow chemistry methodology including photochemistry, electrochemistry, and the handling of "dangerous" reagents. Also featured are advances in the "computer-assisted drug design" area and the expanding application of novel mass spectrometry-based techniques to a wide range of drug discovery activities.

  7. Computing protein infrared spectroscopy with quantum chemistry.

    Science.gov (United States)

    Besley, Nicholas A

    2007-12-15

    Quantum chemistry is a field of science that has undergone unprecedented advances in the last 50 years. From the pioneering work of Boys in the 1950s, quantum chemistry has evolved from being regarded as a specialized and esoteric discipline to a widely used tool that underpins much of the current research in chemistry today. This achievement was recognized with the award of the 1998 Nobel Prize in Chemistry to John Pople and Walter Kohn. As the new millennium unfolds, quantum chemistry stands at the forefront of an exciting new era. Quantitative calculations on systems of the magnitude of proteins are becoming a realistic possibility, an achievement that would have been unimaginable to the early pioneers of quantum chemistry. In this article we will describe ongoing work towards this goal, focusing on the calculation of protein infrared amide bands directly with quantum chemical methods.

  8. JACOB: An Enterprise Framework for Computational Chemistry

    Science.gov (United States)

    Waller, Mark P; Dresselhaus, Thomas; Yang, Jack

    2013-01-01

    Here, we present just a collection of beans (JACOB): an integrated batch-based framework designed for the rapid development of computational chemistry applications. The framework expedites developer productivity by handling the generic infrastructure tier, and can be easily extended by user-specific scientific code. Paradigms from enterprise software engineering were rigorously applied to create a scalable, testable, secure, and robust framework. A centralized web application is used to configure and control the operation of the framework. The application-programming interface provides a set of generic tools for processing large-scale noninteractive jobs (e.g., systematic studies), or for coordinating systems integration (e.g., complex workflows). The code for the JACOB framework is open sourced and is available at: http://www.wallerlab.org/jacob. © 2013 Wiley Periodicals, Inc. PMID:23553271

  9. JACOB: an enterprise framework for computational chemistry.

    Science.gov (United States)

    Waller, Mark P; Dresselhaus, Thomas; Yang, Jack

    2013-06-15

    Here, we present just a collection of beans (JACOB): an integrated batch-based framework designed for the rapid development of computational chemistry applications. The framework expedites developer productivity by handling the generic infrastructure tier, and can be easily extended by user-specific scientific code. Paradigms from enterprise software engineering were rigorously applied to create a scalable, testable, secure, and robust framework. A centralized web application is used to configure and control the operation of the framework. The application-programming interface provides a set of generic tools for processing large-scale noninteractive jobs (e.g., systematic studies), or for coordinating systems integration (e.g., complex workflows). The code for the JACOB framework is open sourced and is available at: www.wallerlab.org/jacob. Copyright © 2013 Wiley Periodicals, Inc.

  10. Nanoinformatics: an emerging area of information technology at the intersection of bioinformatics, computational chemistry and nanobiotechnology

    Directory of Open Access Journals (Sweden)

    Fernando González-Nilo

    2011-01-01

    Full Text Available After the progress made during the genomics era, bioinformatics was tasked with supporting the flow of information generated by nanobiotechnology efforts. This challenge requires adapting classical bioinformatic and computational chemistry tools to store, standardize, analyze, and visualize nanobiotechnological information. Thus, old and new bioinformatic and computational chemistry tools have been merged into a new sub-discipline: nanoinformatics. This review takes a second look at the development of this new and exciting area as seen from the perspective of the evolution of nanobiotechnology applied to the life sciences. The knowledge obtained at the nano-scale level implies answers to new questions and the development of new concepts in different fields. The rapid convergence of technologies around nanobiotechnologies has spun off collaborative networks and web platforms created for sharing and discussing the knowledge generated in nanobiotechnology. The implementation of new database schemes suitable for storage, processing and integrating physical, chemical, and biological properties of nanoparticles will be a key element in achieving the promises in this convergent field. In this work, we will review some applications of nanobiotechnology to life sciences in generating new requirements for diverse scientific fields, such as bioinformatics and computational chemistry.

  11. Quantum chemistry in environmental pesticide risk assessment.

    Science.gov (United States)

    Villaverde, Juan J; López-Goti, Carmen; Alcamí, Manuel; Lamsabhi, Al Mokhtar; Alonso-Prados, José L; Sandín-España, Pilar

    2017-11-01

    The scientific community and regulatory bodies worldwide, currently promote the development of non-experimental tests that produce reliable data for pesticide risk assessment. The use of standard quantum chemistry methods could allow the development of tools to perform a first screening of compounds to be considered for the experimental studies, improving the risk assessment. This fact results in a better distribution of resources and in better planning, allowing a more exhaustive study of the pesticides and their metabolic products. The current paper explores the potential of quantum chemistry in modelling toxicity and environmental behaviour of pesticides and their by-products by using electronic descriptors obtained computationally. Quantum chemistry has potential to estimate the physico-chemical properties of pesticides, including certain chemical reaction mechanisms and their degradation pathways, allowing modelling of the environmental behaviour of both pesticides and their by-products. In this sense, theoretical methods can contribute to performing a more focused risk assessment of pesticides used in the market, and may lead to higher quality and safer agricultural products. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. FOREWORD: Third Nordic Symposium on Computer Simulation in Physics, Chemistry, Biology and Mathematics

    Science.gov (United States)

    Kaski, K.; Salomaa, M.

    1990-01-01

    These are Proceedings of the Third Nordic Symposium on Computer Simulation in Physics, Chemistry, Biology, and Mathematics, held August 25-26, 1989, at Lahti (Finland). The Symposium belongs to an annual series of Meetings, the first one of which was arranged in 1987 at Lund (Sweden) and the second one in 1988 at Kolle-Kolle near Copenhagen (Denmark). Although these Symposia have thus far been essentially Nordic events, their international character has increased significantly; the trend is vividly reflected through contributions in the present Topical Issue. The interdisciplinary nature of Computational Science is central to the activity; this fundamental aspect is also responsible, in an essential way, for its rapidly increasing impact. Crucially important to a wide spectrum of superficially disparate fields is the common need for extensive - and often quite demanding - computational modelling. For such theoretical models, no closed-form (analytical) solutions are available or they would be extremely difficult to find; hence one must rather resort to the Art of performing computational investigations. Among the unifying features in the computational research are the methods of simulation employed; methods which frequently are quite closely related with each other even for faculties of science that are quite unrelated. Computer simulation in Natural Sciences is presently apprehended as a discipline on its own right, occupying a broad region somewhere between the experimental and theoretical methods, but also partially overlapping with and complementing them. - Whichever its proper definition may be, the computational approach serves as a novel and an extremely versatile tool with which one can equally well perform "pure" experimental modelling and conduct "computational theory". Computational studies that have earlier been made possible only through supercomputers have opened unexpected, as well as exciting, novel frontiers equally in mathematics (e.g., fractals

  13. Atomdroid: a computational chemistry tool for mobile platforms.

    Science.gov (United States)

    Feldt, Jonas; Mata, Ricardo A; Dieterich, Johannes M

    2012-04-23

    We present the implementation of a new molecular mechanics program designed for use in mobile platforms, the first specifically built for these devices. The software is designed to run on Android operating systems and is compatible with several modern tablet-PCs and smartphones available in the market. It includes molecular viewer/builder capabilities with integrated routines for geometry optimizations and Monte Carlo simulations. These functionalities allow it to work as a stand-alone tool. We discuss some particular development aspects, as well as the overall feasibility of using computational chemistry software packages in mobile platforms. Benchmark calculations show that through efficient implementation techniques even hand-held devices can be used to simulate midsized systems using force fields.

  14. Current status and future prospects for enabling chemistry technology in the drug discovery process

    Science.gov (United States)

    Djuric, Stevan W.; Hutchins, Charles W.; Talaty, Nari N.

    2016-01-01

    This review covers recent advances in the implementation of enabling chemistry technologies into the drug discovery process. Areas covered include parallel synthesis chemistry, high-throughput experimentation, automated synthesis and purification methods, flow chemistry methodology including photochemistry, electrochemistry, and the handling of “dangerous” reagents. Also featured are advances in the “computer-assisted drug design” area and the expanding application of novel mass spectrometry-based techniques to a wide range of drug discovery activities. PMID:27781094

  15. Reaction of formaldehyde at the ortho- and para-positions of phenol: exploration of mechanisms using computational chemistry.

    Science.gov (United States)

    Anthony H. Conner; Melissa S. Reeves

    2001-01-01

    Computational chemistry methods can be used to explore the theoretical chemistry behind reactive systems, to compare the relative chemical reactivity of different systems, and, by extension, to predict the reactivity of new systems. Ongoing research has focused on the reactivity of a wide variety of phenolic compounds with formaldehyde using semi-empirical and ab...

  16. Faster quantum chemistry simulation on fault-tolerant quantum computers

    International Nuclear Information System (INIS)

    Cody Jones, N; McMahon, Peter L; Yamamoto, Yoshihisa; Whitfield, James D; Yung, Man-Hong; Aspuru-Guzik, Alán; Van Meter, Rodney

    2012-01-01

    Quantum computers can in principle simulate quantum physics exponentially faster than their classical counterparts, but some technical hurdles remain. We propose methods which substantially improve the performance of a particular form of simulation, ab initio quantum chemistry, on fault-tolerant quantum computers; these methods generalize readily to other quantum simulation problems. Quantum teleportation plays a key role in these improvements and is used extensively as a computing resource. To improve execution time, we examine techniques for constructing arbitrary gates which perform substantially faster than circuits based on the conventional Solovay–Kitaev algorithm (Dawson and Nielsen 2006 Quantum Inform. Comput. 6 81). For a given approximation error ϵ, arbitrary single-qubit gates can be produced fault-tolerantly and using a restricted set of gates in time which is O(log ϵ) or O(log log ϵ); with sufficient parallel preparation of ancillas, constant average depth is possible using a method we call programmable ancilla rotations. Moreover, we construct and analyze efficient implementations of first- and second-quantized simulation algorithms using the fault-tolerant arbitrary gates and other techniques, such as implementing various subroutines in constant time. A specific example we analyze is the ground-state energy calculation for lithium hydride. (paper)

  17. Planning Committee for a National Resource for Computation in Chemistry. Final report, October 1, 1974--June 30, 1977

    International Nuclear Information System (INIS)

    1978-11-01

    The Planning Committee for a National Resource for Computation in Chemistry (NRCC) was charged with the responsibility of formulating recommendations regarding organizational structure for an NRCC including the composition, size, and responsibilities of its policy board, the relationship of such a board to the operating structure of the NRCC, to federal funding agencies, and to user groups; desirable priorities, growth rates, and levels of operations for the first several years; and facilities, access and site requirements for such a Resource. By means of site visits, questionnaires, and a workshop, the Committee sought advice from a wide range of potential users and organizations interested in chemical computation. Chemical kinetics, crystallography, macromolecular science, nonnumerical methods, physical organic chemistry, quantum chemistry, and statistical mechanics are covered

  18. Planning Committee for a National Resource for Computation in Chemistry. Final report, October 1, 1974--June 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Bigeleisen, Jacob; Berne, Bruce J.; Coton, F. Albert; Scheraga, Harold A.; Simmons, Howard E.; Snyder, Lawrence C.; Wiberg, Kenneth B.; Wipke, W. Todd

    1978-11-01

    The Planning Committee for a National Resource for Computation in Chemistry (NRCC) was charged with the responsibility of formulating recommendations regarding organizational structure for an NRCC including the composition, size, and responsibilities of its policy board, the relationship of such a board to the operating structure of the NRCC, to federal funding agencies, and to user groups; desirable priorities, growth rates, and levels of operations for the first several years; and facilities, access and site requirements for such a Resource. By means of site visits, questionnaires, and a workshop, the Committee sought advice from a wide range of potential users and organizations interested in chemical computation. Chemical kinetics, crystallography, macromolecular science, nonnumerical methods, physical organic chemistry, quantum chemistry, and statistical mechanics are covered.

  19. Mathematical Chemistry

    OpenAIRE

    Trinajstić, Nenad; Gutman, Ivan

    2002-01-01

    A brief description is given of the historical development of mathematics and chemistry. A path leading to the meeting of these two sciences is described. An attempt is made to define mathematical chemistry, and journals containing the term mathematical chemistry in their titles are noted. In conclusion, the statement is made that although chemistry is an experimental science aimed at preparing new compounds and materials, mathematics is very useful in chemistry, among other things, to produc...

  20. Using Free Computational Resources to Illustrate the Drug Design Process in an Undergraduate Medicinal Chemistry Course

    Science.gov (United States)

    Rodrigues, Ricardo P.; Andrade, Saulo F.; Mantoani, Susimaire P.; Eifler-Lima, Vera L.; Silva, Vinicius B.; Kawano, Daniel F.

    2015-01-01

    Advances in, and dissemination of, computer technologies in the field of drug research now enable the use of molecular modeling tools to teach important concepts of drug design to chemistry and pharmacy students. A series of computer laboratories is described to introduce undergraduate students to commonly adopted "in silico" drug design…

  1. The Impact of Learner's Prior Knowledge on Their Use of Chemistry Computer Simulations: A Case Study

    Science.gov (United States)

    Liu, Han-Chin; Andre, Thomas; Greenbowe, Thomas

    2008-01-01

    It is complicated to design a computer simulation that adapts to students with different characteristics. This study documented cases that show how college students' prior chemistry knowledge level affected their interaction with peers and their approach to solving problems with the use of computer simulations that were designed to learn…

  2. GRID computing for experimental high energy physics

    International Nuclear Information System (INIS)

    Moloney, G.R.; Martin, L.; Seviour, E.; Taylor, G.N.; Moorhead, G.F.

    2002-01-01

    Full text: The Large Hadron Collider (LHC), to be completed at the CERN laboratory in 2006, will generate 11 petabytes of data per year. The processing of this large data stream requires a large, distributed computing infrastructure. A recent innovation in high performance distributed computing, the GRID, has been identified as an important tool in data analysis for the LHC. GRID computing has actual and potential application in many fields which require computationally intensive analysis of large, shared data sets. The Australian experimental High Energy Physics community has formed partnerships with the High Performance Computing community to establish a GRID node at the University of Melbourne. Through Australian membership of the ATLAS experiment at the LHC, Australian researchers have an opportunity to be involved in the European DataGRID project. This presentation will include an introduction to the GRID, and it's application to experimental High Energy Physics. We will present the results of our studies, including participation in the first LHC data challenge

  3. Introduction to Computational Chemistry: Teaching Hu¨ckel Molecular Orbital Theory Using an Excel Workbook for Matrix Diagonalization

    Science.gov (United States)

    Litofsky, Joshua; Viswanathan, Rama

    2015-01-01

    Matrix diagonalization, the key technique at the heart of modern computational chemistry for the numerical solution of the Schrödinger equation, can be easily introduced in the physical chemistry curriculum in a pedagogical context using simple Hückel molecular orbital theory for p bonding in molecules. We present details and results of…

  4. Containment Sodium Chemistry Models in MELCOR.

    Energy Technology Data Exchange (ETDEWEB)

    Louie, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Humphries, Larry L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Denman, Matthew R [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-04-01

    To meet regulatory needs for sodium fast reactors’ future development, including licensing requirements, Sandia National Laboratories is modernizing MELCOR, a severe accident analysis computer code developed for the U.S. Nuclear Regulatory Commission (NRC). Specifically, Sandia is modernizing MELCOR to include the capability to model sodium reactors. However, Sandia’s modernization effort primarily focuses on the containment response aspects of the sodium reactor accidents. Sandia began modernizing MELCOR in 2013 to allow a sodium coolant, rather than water, for conventional light water reactors. In the past three years, Sandia has been implementing the sodium chemistry containment models in CONTAIN-LMR, a legacy NRC code, into MELCOR. These chemistry models include spray fire, pool fire and atmosphere chemistry models. Only the first two chemistry models have been implemented though it is intended to implement all these models into MELCOR. A new package called “NAC” has been created to manage the sodium chemistry model more efficiently. In 2017 Sandia began validating the implemented models in MELCOR by simulating available experiments. The CONTAIN-LMR sodium models include sodium atmosphere chemistry and sodium-concrete interaction models. This paper presents sodium property models, the implemented models, implementation issues, and a path towards validation against existing experimental data.

  5. Application of computer assisted combinatorial chemistry in antivirial, antimalarial and anticancer agents design

    Science.gov (United States)

    Burello, E.; Bologa, C.; Frecer, V.; Miertus, S.

    Combinatorial chemistry and technologies have been developed to a stage where synthetic schemes are available for generation of a large variety of organic molecules. The innovative concept of combinatorial design assumes that screening of a large and diverse library of compounds will increase the probability of finding an active analogue among the compounds tested. Since the rate at which libraries are screened for activity currently constitutes a limitation to the use of combinatorial technologies, it is important to be selective about the number of compounds to be synthesized. Early experience with combinatorial chemistry indicated that chemical diversity alone did not result in a significant increase in the number of generated lead compounds. Emphasis has therefore been increasingly put on the use of computer assisted combinatorial chemical techniques. Computational methods are valuable in the design of virtual libraries of molecular models. Selection strategies based on computed physicochemical properties of the models or of a target compound are introduced to reduce the time and costs of library synthesis and screening. In addition, computational structure-based library focusing methods can be used to perform in silico screening of the activity of compounds against a target receptor by docking the ligands into the receptor model. Three case studies are discussed dealing with the design of targeted combinatorial libraries of inhibitors of HIV-1 protease, P. falciparum plasmepsin and human urokinase as potential antivirial, antimalarial and anticancer drugs. These illustrate library focusing strategies.

  6. Computational and experimental methods for enclosed natural convection

    International Nuclear Information System (INIS)

    Larson, D.W.; Gartling, D.K.; Schimmel, W.P. Jr.

    1977-10-01

    Two computational procedures and one optical experimental procedure for studying enclosed natural convection are described. The finite-difference and finite-element numerical methods are developed and several sample problems are solved. Results obtained from the two computational approaches are compared. A temperature-visualization scheme using laser holographic interferometry is described, and results from this experimental procedure are compared with results from both numerical methods

  7. Positronium chemistry

    CERN Document Server

    Green, James

    1964-01-01

    Positronium Chemistry focuses on the methodologies, reactions, processes, and transformations involved in positronium chemistry. The publication first offers information on positrons and positronium and experimental methods, including mesonic atoms, angular correlation measurements, annihilation spectra, and statistical errors in delayed coincidence measurements. The text then ponders on positrons in gases and solids. The manuscript takes a look at the theoretical chemistry of positronium and positronium chemistry in gases. Topics include quenching, annihilation spectrum, delayed coincidence

  8. Research and Teaching: Computational Methods in General Chemistry--Perceptions of Programming, Prior Experience, and Student Outcomes

    Science.gov (United States)

    Wheeler, Lindsay B.; Chiu, Jennie L.; Grisham, Charles M.

    2016-01-01

    This article explores how integrating computational tools into a general chemistry laboratory course can influence student perceptions of programming and investigates relationships among student perceptions, prior experience, and student outcomes.

  9. Computational chemistry and metal-based radiopharmaceuticals

    International Nuclear Information System (INIS)

    Neves, M.; Fausto, R.

    1998-01-01

    Computer-assisted techniques have found extensive use in the design of organic pharmaceuticals but have not been widely applied on metal complexes, particularly on radiopharmaceuticals. Some examples of computer generated structures of complexes of In, Ga and Tc with N, S, O and P donor ligands are referred. Besides parameters directly related with molecular geometries, molecular properties of the predicted structures, as ionic charges or dipole moments, are considered to be related with biodistribution studies. The structure of a series of oxo neutral Tc-biguanide complexes are predicted by molecular mechanics calculations, and their interactions with water molecules or peptide chains correlated with experimental data of partition coefficients and percentage of human protein binding. The results stress the interest of using molecular modelling to predict molecular properties of metal-based radiopharmaceuticals, which can be successfully correlated with results of in vitro studies. (author)

  10. Using computer-aided drug design and medicinal chemistry strategies in the fight against diabetes.

    Science.gov (United States)

    Semighini, Evandro P; Resende, Jonathan A; de Andrade, Peterson; Morais, Pedro A B; Carvalho, Ivone; Taft, Carlton A; Silva, Carlos H T P

    2011-04-01

    The aim of this work is to present a simple, practical and efficient protocol for drug design, in particular Diabetes, which includes selection of the illness, good choice of a target as well as a bioactive ligand and then usage of various computer aided drug design and medicinal chemistry tools to design novel potential drug candidates in different diseases. We have selected the validated target dipeptidyl peptidase IV (DPP-IV), whose inhibition contributes to reduce glucose levels in type 2 diabetes patients. The most active inhibitor with complex X-ray structure reported was initially extracted from the BindingDB database. By using molecular modification strategies widely used in medicinal chemistry, besides current state-of-the-art tools in drug design (including flexible docking, virtual screening, molecular interaction fields, molecular dynamics, ADME and toxicity predictions), we have proposed 4 novel potential DPP-IV inhibitors with drug properties for Diabetes control, which have been supported and validated by all the computational tools used herewith.

  11. Routine operation of an Elliott 903 computer in a clinical chemistry laboratory

    Science.gov (United States)

    Whitby, L. G.; Simpson, D.

    1973-01-01

    Experience gained in the last four years concerning the capabilities and limitations of an 8K Elliott 903 (18-bit word) computer with magnetic tape backing store in the routine operation of a clinical chemistry laboratory is described. Designed as a total system, routine operation has latterly had to be confined to data acquisition and process control functions, due primarily to limitations imposed by the choice of hardware early in the project. In this final report of a partially successful experiment the opportunity is taken to review mistakes made, especially at the start of the project, to warn potential computer users of pitfalls to be avoided. PMID:4580240

  12. Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

    Energy Technology Data Exchange (ETDEWEB)

    Holm, J.; Glaenneskog, H.; Ekberg, C. (Chalmers Univ. of Technology (Sweden)); Kaerkelae, T.; Auvinen, A. (VTT Technical Research Centre of Finland (Finland))

    2010-05-15

    An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment was started. During 2009, oxidation of iodine, especially organic iodine, was studied within the NROI project. The chemistry of organic iodine in the gas phase is still one of the greatest remaining uncertainties concerning iodine behaviour during a severe accident. During the first year of the NROI project the oxidation of elemental iodine, I2, with ozone and UV-light was investigated. In this study organic iodide, in this case methyl iodide, was investigated in similar conditions as in the NROI-1 project. The experimental facility applied in this study is based on the sampling system built at VTT for the ISTP project CHIP conducted by IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UVC intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. Instant and extensive particle formation occurred when methyl iodide was transported through a UVC radiation field and/or when ozone was present. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-150 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine

  13. Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

    International Nuclear Information System (INIS)

    Holm, J.; Glaenneskog, H.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.

    2010-05-01

    An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment was started. During 2009, oxidation of iodine, especially organic iodine, was studied within the NROI project. The chemistry of organic iodine in the gas phase is still one of the greatest remaining uncertainties concerning iodine behaviour during a severe accident. During the first year of the NROI project the oxidation of elemental iodine, I2, with ozone and UV-light was investigated. In this study organic iodide, in this case methyl iodide, was investigated in similar conditions as in the NROI-1 project. The experimental facility applied in this study is based on the sampling system built at VTT for the ISTP project CHIP conducted by IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UVC intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. Instant and extensive particle formation occurred when methyl iodide was transported through a UVC radiation field and/or when ozone was present. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-150 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine

  14. Multi-level computational chemistry study on hydrogen recombination catalyst of off-gas treatment system

    International Nuclear Information System (INIS)

    Hatakeyama, Nozomu; Ise, Mariko; Inaba, Kenji

    2011-01-01

    In order to reveal the deactivation mechanism of the hydrogen recombination catalyst of off-gas treatment system, we investigate by using multi-level computational chemistry simulation methods. The recombiner apparatus is modeled by the numerical mesh system in the axial coordinates, and unsteady, advection and reaction rate equations are solved by using a finite difference method. The chemical reactions are formulated to represent adsorption-desorption of hydrogen and oxygen on Pt catalyst, and time developments of the coverage factors of Pt are solved numerically. The computational simulations successfully reproduce the very similar behaviors observed by experiments, such as increasing of the inversion rates of H 2 to H 2 O, the temperatures distributions along the flow direction, dependencies of experimental condition, and so on. Thus Pt poisoning is considered to cause the deactivation of the hydrogen recombination catalyst. To clarify the poisoning mechanism, the molecular level simulation is applied to the system of Pt on boehmite attacked by a cyclic siloxane which has been detected by experiments and considered as one of poisoning spices. The simulation shows ring-opening reaction of the cyclic siloxane on Pt, then attachment of two ends of the chain-like siloxane to Pt and boehmite, respectively, and that finally the recombination reaction is prevented. This may be the first study to find out the detailed dynamical mechanism of hydrogen recombination catalyst poisoning with cyclic siloxane. (author)

  15. Experimental quantum computing without entanglement.

    Science.gov (United States)

    Lanyon, B P; Barbieri, M; Almeida, M P; White, A G

    2008-11-14

    Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of computation that uses highly mixed states. Unlike pure-state models, its power is not derived from the generation of a large amount of entanglement. Instead it has been proposed that other nonclassical correlations are responsible for the computational speedup, and that these can be captured by the quantum discord. In this Letter we implement DQC1 in an all-optical architecture, and experimentally observe the generated correlations. We find no entanglement, but large amounts of quantum discord-except in three cases where an efficient classical simulation is always possible. Our results show that even fully separable, highly mixed, states can contain intrinsically quantum mechanical correlations and that these could offer a valuable resource for quantum information technologies.

  16. Transforming the Organic Chemistry Lab Experience: Design, Implementation, and Evaluation of Reformed Experimental Activities--REActivities

    Science.gov (United States)

    Collison, Christina G.; Kim, Thomas; Cody, Jeremy; Anderson, Jason; Edelbach, Brian; Marmor, William; Kipsang, Rodgers; Ayotte, Charles; Saviola, Daniel; Niziol, Justin

    2018-01-01

    Reformed experimental activities (REActivities) are an innovative approach to the delivery of the traditional material in an undergraduate organic chemistry laboratory. A description of the design and implementation of REActivities at both a four- and two-year institution is discussed. The results obtained using a reformed teaching observational…

  17. Development of the experimental evaluation method for crevice chemistry in steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, In Hyoung [Soonchunghyang Univ., Cheonan (Korea); Hwang, Il Soon; Lee, Na Young; Kim, Ji Hyun; Lim, Jung Yeon; Bahn, Chi Bum; Oh, Young Jin; Han, Byung Chan; Oh, Si Hyoung [Seoul National Univ., Seoul (Korea)

    2001-04-01

    Steam generator tube degradation problems is very sensitive to water chemistry. But even if the secondary water chemistry is well controlled, it is needed. Tubesheet crevice has three boiling regimes with depth: liquid penetration and discharge(or wet) region, liquid drop scattering(or dry and wet) region, and dryout region. This results showed a good agreement with earlier works. High temperature, high pressure tubesheet crevice simulation system was constructed. As {delta}T increased, the temperature gradient in crevice and time constant for concentration increased. When the experimental results were compared with MULTEQ calculation results, a similar behavior was shown, packed crevice have longer time constant for Na concentration and showed heavier concentration that open crevice. The verification experiment for Molar Ratio Control and advanced Molar Ration Control test were conducted. To check the applicability of boric acid as pH neutralizer another experiment was conducted. 40 refs., 102 figs., 3 tabs. (Author)

  18. Enhancing prospective chemistry teachers cognitive structures in the topics of bonding and hybridization by internet-assisted chemistry applications

    Directory of Open Access Journals (Sweden)

    Özge Özyalçın Oskay, Sinem Dinçol

    2011-08-01

    Full Text Available The purpose of this study is to determine the effects of internet-assisted chemistry applications on prospective chemistry teachers’ cognitive structures in the topics of bonding and hybridization. The sample of the study consisted of 36 prospective chemistry teachers attending Hacettepe University, Faculty of Education, the Department of Chemistry Education in 2010-2011 academic year and taking Basic Chemistry I lesson. In the study, students were separated into experimental and control groups according to their pre-cognitive structures. Students were requested to answer two open ended questions. Answers by each student were gathered and evaluated by flow map method. “Bonding and hybridization” topics were taught to control group with traditional teaching method and to experimental group besides traditional method internet-assisted applications were conducted. The same open-ended questions were given to both groups and their cognitive structures were examined once more. The differences between control and experimental groups’ cognitive structures were examined. A significant difference was identified in favour of experimental group (p<0, 05. The mean score of the Experimental group was X=19.94, and the mean score of the Control group was X=13.88. In addition, subsequent to internet assisted chemistry applications differences in terms of concepts and descriptions in prospective chemistry teachers’ in experimental and control group cognitive structure have been determined. When post flow maps of prospective chemistry teachers in experimental group, on whom internet assisted chemistry applications were made, are formed, it has been determined that there are more statements about hybridization, hybridization types, molecule geometry and bond angles compared to control grou

  19. Methods and experimental techniques in computer engineering

    CERN Document Server

    Schiaffonati, Viola

    2014-01-01

    Computing and science reveal a synergic relationship. On the one hand, it is widely evident that computing plays an important role in the scientific endeavor. On the other hand, the role of scientific method in computing is getting increasingly important, especially in providing ways to experimentally evaluate the properties of complex computing systems. This book critically presents these issues from a unitary conceptual and methodological perspective by addressing specific case studies at the intersection between computing and science. The book originates from, and collects the experience of, a course for PhD students in Information Engineering held at the Politecnico di Milano. Following the structure of the course, the book features contributions from some researchers who are working at the intersection between computing and science.

  20. Very high temperature chemistry: Science justification for containerless experimentation in space

    Science.gov (United States)

    Hofmeister, William H.; Nordine, Paul

    1990-01-01

    A summary is presented of the justification for application of containerless processing in space to high temperature science. Low earth orbit offers a gravitational environment that allows samples to be positioned in an experimental apparatus by very small forces. Well controlled experiments become possible on reactive materials at high temperatures in a reasonably quiescent state and without container contamination. This provides an opportunity to advance the science of high temperature chemistry that can only be realized with a commitment by NASA to provide advanced facilities for in-space containerless study of materials at very high temperature.

  1. Electron tunneling in chemistry

    International Nuclear Information System (INIS)

    Zamaraev, K.I.; Khajrutdinov, R.F.; Zhdanov, V.P.; Molin, Yu.N.

    1985-01-01

    Results of experimental and theoretical investigations are outlined systematically on electron tunnelling in chemical reactions. Mechanism of electron transport to great distances is shown to be characteristic to chemical compounds of a wide range. The function of tunnel reactions is discussed for various fields of chemistry, including radiation chemistry, electrochemistry, chemistry of solids, chemistry of surface and catalysis

  2. Effects of watershed experiments on water chemistry at the Marcell Experimental Forest. Chapter 14.

    Science.gov (United States)

    Stephen D. Sebestyen; Elon S. Verry

    2011-01-01

    The Marcell Experimental Forest (MEF) was established during the 1960s to study the hydrology and ecology of lowland watersheds where upland mineral soils drain to central peatlands (Boelter and Verry 1977). The effects of seven large-scale manipulations on water chemistry have been studied on the MEF watersheds and the data now span up to four decades. In this chapter...

  3. plasmaFoam: An OpenFOAM framework for computational plasma physics and chemistry

    Science.gov (United States)

    Venkattraman, Ayyaswamy; Verma, Abhishek Kumar

    2016-09-01

    As emphasized in the 2012 Roadmap for low temperature plasmas (LTP), scientific computing has emerged as an essential tool for the investigation and prediction of the fundamental physical and chemical processes associated with these systems. While several in-house and commercial codes exist, with each having its own advantages and disadvantages, a common framework that can be developed by researchers from all over the world will likely accelerate the impact of computational studies on advances in low-temperature plasma physics and chemistry. In this regard, we present a finite volume computational toolbox to perform high-fidelity simulations of LTP systems. This framework, primarily based on the OpenFOAM solver suite, allows us to enhance our understanding of multiscale plasma phenomenon by performing massively parallel, three-dimensional simulations on unstructured meshes using well-established high performance computing tools that are widely used in the computational fluid dynamics community. In this talk, we will present preliminary results obtained using the OpenFOAM-based solver suite with benchmark three-dimensional simulations of microplasma devices including both dielectric and plasma regions. We will also discuss the future outlook for the solver suite.

  4. Computer system for Monte Carlo experimentation

    International Nuclear Information System (INIS)

    Grier, D.A.

    1986-01-01

    A new computer system for Monte Carlo Experimentation is presented. The new system speeds and simplifies the process of coding and preparing a Monte Carlo Experiment; it also encourages the proper design of Monte Carlo Experiments, and the careful analysis of the experimental results. A new functional language is the core of this system. Monte Carlo Experiments, and their experimental designs, are programmed in this new language; those programs are compiled into Fortran output. The Fortran output is then compiled and executed. The experimental results are analyzed with a standard statistics package such as Si, Isp, or Minitab or with a user-supplied program. Both the experimental results and the experimental design may be directly loaded into the workspace of those packages. The new functional language frees programmers from many of the details of programming an experiment. Experimental designs such as factorial, fractional factorial, or latin square are easily described by the control structures and expressions of the language. Specific mathematical modes are generated by the routines of the language

  5. AN APPLICATION OF THE LOGISTIC REGRESSION MODEL IN THE EXPERIMENTAL PHYSICAL CHEMISTRY

    Directory of Open Access Journals (Sweden)

    Elpidio Corral-López

    2015-06-01

    Full Text Available The calculation of intensive properties molar volumes of ethanol-water mixtures by experimental densities and tangent method in the Physical Chemistry Laboratory presents the problem of making manually the molar volume curve versus mole fraction and the trace of the tangent line trace. The advantage of using a statistical model the Logistic Regression on a Texas VOYAGE graphing calculator allowed trace the curve and the tangents in situ, and also evaluate the students work during the experimental session. The error percentage between the molar volumes calculated using literature data and those obtained with statistical method is minimal, which validates the model. It is advantageous use the calculator with this application as a teaching support tool, reducing the evaluation time of 3 weeks to 3 hours.

  6. Experimental demonstration of deterministic one-way quantum computing on a NMR quantum computer

    OpenAIRE

    Ju, Chenyong; Zhu, Jing; Peng, Xinhua; Chong, Bo; Zhou, Xianyi; Du, Jiangfeng

    2008-01-01

    One-way quantum computing is an important and novel approach to quantum computation. By exploiting the existing particle-particle interactions, we report the first experimental realization of the complete process of deterministic one-way quantum Deutsch-Josza algorithm in NMR, including graph state preparation, single-qubit measurements and feed-forward corrections. The findings in our experiment may shed light on the future scalable one-way quantum computation.

  7. Chemical Equilibrium, Unit 2: Le Chatelier's Principle. A Computer-Enriched Module for Introductory Chemistry. Student's Guide and Teacher's Guide.

    Science.gov (United States)

    Jameson, A. Keith

    Presented are the teacher's guide and student materials for one of a series of self-instructional, computer-based learning modules for an introductory, undergraduate chemistry course. The student manual for this unit on Le Chatelier's principle includes objectives, prerequisites, pretest, instructions for executing the computer program, and…

  8. Current status and future prospects for enabling chemistry technology in the drug discovery process [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Stevan W. Djuric

    2016-09-01

    Full Text Available This review covers recent advances in the implementation of enabling chemistry technologies into the drug discovery process. Areas covered include parallel synthesis chemistry, high-throughput experimentation, automated synthesis and purification methods, flow chemistry methodology including photochemistry, electrochemistry, and the handling of “dangerous” reagents. Also featured are advances in the “computer-assisted drug design” area and the expanding application of novel mass spectrometry-based techniques to a wide range of drug discovery activities.

  9. Thermodynamics of natural selection III: Landauer's principle in computation and chemistry.

    Science.gov (United States)

    Smith, Eric

    2008-05-21

    This is the third in a series of three papers devoted to energy flow and entropy changes in chemical and biological processes, and their relations to the thermodynamics of computation. The previous two papers have developed reversible chemical transformations as idealizations for studying physiology and natural selection, and derived bounds from the second law of thermodynamics, between information gain in an ensemble and the chemical work required to produce it. This paper concerns the explicit mapping of chemistry to computation, and particularly the Landauer decomposition of irreversible computations, in which reversible logical operations generating no heat are separated from heat-generating erasure steps which are logically irreversible but thermodynamically reversible. The Landauer arrangement of computation is shown to produce the same entropy-flow diagram as that of the chemical Carnot cycles used in the second paper of the series to idealize physiological cycles. The specific application of computation to data compression and error-correcting encoding also makes possible a Landauer analysis of the somewhat different problem of optimal molecular recognition, which has been considered as an information theory problem. It is shown here that bounds on maximum sequence discrimination from the enthalpy of complex formation, although derived from the same logical model as the Shannon theorem for channel capacity, arise from exactly the opposite model for erasure.

  10. An approach to quality and performance control in a computer-assisted clinical chemistry laboratory.

    Science.gov (United States)

    Undrill, P E; Frazer, S C

    1979-01-01

    A locally developed, computer-based clinical chemistry laboratory system has been in operation since 1970. This utilises a Digital Equipment Co Ltd PDP 12 and an interconnected PDP 8/F computer. Details are presented of the performance and quality control techniques incorporated into the system. Laboratory performance is assessed through analysis of results from fixed-level control sera as well as from cumulative sum methods. At a simple level the presentation may be considered purely indicative, while at a more sophisticated level statistical concepts have been introduced to aid the laboratory controller in decision-making processes. PMID:438340

  11. Effectiveness of Using Computer-Assisted Supplementary Instruction for Teaching the Mole Concept

    Science.gov (United States)

    Yalçinalp, Serpil; Geban, Ömer; Özkan, Ilker

    This study examined the effect of computer-assisted instruction (CAI), used as a problem-solving supplement to classroom instruction, on students' understanding of chemical formulas and mole concept, their attitudes toward chemistry subjects, and CAI. The objective was to assess the effectiveness of CAI over recitation hours when both teaching methods were used as a supplement to the traditional chemistry instruction. We randomly selected two classes in a secondary school. Each teaching strategy was randomly assigned to one class. The experimental group received supplementary instruction delivered via CAI, while the control group received similar instruction through recitation hours. The data were analyzed using two-way analysis of variance and t-test. It was found that the students who used the CAI accompanied with lectures scored significantly higher than those who attended recitation hours, in terms of school subject achievement in chemistry and attitudes toward chemistry subjects. In addition, there was a significant improvement in the attitudes of students in the experimental group toward the use of computers in a chemistry course. There was no significant difference between the performances of females versus males in each treatment group.Received: 26 April 1994; Revised: 6 April 1995;

  12. Experimental interstellar organic chemistry: Preliminary findings

    Science.gov (United States)

    Khare, B. N.; Sagan, C.

    1971-01-01

    In a simulation of interstellar organic chemistry in dense interstellar clouds or on grain surfaces, formaldehyde, water vapor, ammonia and ethane are deposited on a quartz cold finger and ultraviolet-irradiated in high vacuum at 77K. The HCHO photolytic pathway which produces an aldehyde radical and a superthermal hydrogen atom initiates solid phase chain reactions leading to a range of new compounds, including methanol, ethanol, acetaldehyde, acetonitrile, acetone, methyl formate, and possibly formic acid. Higher nitriles are anticipated. Genetic relations among these interstellar organic molecules (e.g., the Cannizzaro and Tischenko reactions) must exist. Some of them, rather than being synthesized from smaller molecules, may be degradation products of larger organic molecules, such as hexamethylene tetramine, which are candidate consitituents of the interstellar grains. The experiments reported here may also be relevant to cometary chemistry.

  13. Analytical Chemistry Division's sample transaction system

    International Nuclear Information System (INIS)

    Stanton, J.S.; Tilson, P.A.

    1980-10-01

    The Analytical Chemistry Division uses the DECsystem-10 computer for a wide range of tasks: sample management, timekeeping, quality assurance, and data calculation. This document describes the features and operating characteristics of many of the computer programs used by the Division. The descriptions are divided into chapters which cover all of the information about one aspect of the Analytical Chemistry Division's computer processing

  14. Recent progress in orbital-free density functional theory (recent advances in computational chemistry)

    CERN Document Server

    Wesolowski, Tomasz A

    2013-01-01

    This is a comprehensive overview of state-of-the-art computational methods based on orbital-free formulation of density functional theory completed by the most recent developments concerning the exact properties, approximations, and interpretations of the relevant quantities in density functional theory. The book is a compilation of contributions stemming from a series of workshops which had been taking place since 2002. It not only chronicles many of the latest developments but also summarises some of the more significant ones. The chapters are mainly reviews of sub-domains but also include original research. Readership: Graduate students, academics and researchers in computational chemistry. Atomic & molecular physicists, theoretical physicists, theoretical chemists, physical chemists and chemical physicists.

  15. Porewater chemistry in compacted bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Muurinen, A.; Lehikoinen, J. [VTT Chemical Technology, Espoo (Finland)

    1999-03-01

    In this study, the porewater chemistry in compacted bentonite, considered as an engineered barrier in the repository of spent fuel, has been studied in interaction experiments. Many parameters, like the composition and density of bentonite, composition of the solution, bentonite-to-water ratio (B/W), surrounding conditions and experimental time have been varied in the experiments. At the end of the interaction the equilibrating solution, the porewaters squeezed out of the bentonite samples, and bentonites themselves were analyzed to give information for the interpretation and modelling of the interaction. Equilibrium modelling was performed with the HYDRAQL/CE computer code 33 refs.

  16. Physical Chemistry Chemical Kinetics and Reaction Mechanism

    CERN Document Server

    Trimm, Harold H

    2011-01-01

    Physical chemistry covers diverse topics, from biochemistry to materials properties to the development of quantum computers. Physical chemistry applies physics and math to problems that interest chemists, biologists, and engineers. Physical chemists use theoretical constructs and mathematical computations to understand chemical properties and describe the behavior of molecular and condensed matter. Their work involves manipulations of data as well as materials. Physical chemistry entails extensive work with sophisticated instrumentation and equipment as well as state-of-the-art computers. This

  17. A Compilation of Postgraduate Theses Written in Turkey on Computer Assisted Instruction in Chemistry Education

    Science.gov (United States)

    Bozdogan, Aykut Emre; Demirbas, Murat

    2014-01-01

    The purpose of the study conducted is to present in-depth information about the postgraduate theses written within the context of Computer Assisted Instruction in Chemistry Education in Turkey. The theses collected in National Thesis Centre of Turkish Council of Higher Education were examined. As a result of an examination, it was found that about…

  18. The computer library of experimental neutron data

    International Nuclear Information System (INIS)

    Bychkov, V.M.; Manokhin, V.N.; Surgutanov, V.V.

    1976-05-01

    The paper describes the computer library of experimental neutron data at the Obninsk Nuclear Data Centre. The format of the library (EXFOR) and the system of programmes for supplying the library are briefly described. (author)

  19. Experimental and computational development of a natural breast phantom for dosimetry studies

    International Nuclear Information System (INIS)

    Nogueira, Luciana B.; Campos, Tarcisio P.R.

    2013-01-01

    This paper describes the experimental and computational development of a natural breast phantom, anthropomorphic and anthropometric for studies in dosimetry of brachytherapy and teletherapy of breast. The natural breast phantom developed corresponding to fibroadipose breasts of women aged 30 to 50 years, presenting radiographically medium density. The experimental breast phantom was constituted of three tissue-equivalents (TE's): glandular TE, adipose TE and skin TE. These TE's were developed according to chemical composition of human breast and present radiological response to exposure. Completed the construction of experimental breast phantom this was mounted on a thorax phantom previously developed by the research group NRI/UFMG. Then the computational breast phantom was constructed by performing a computed tomography (CT) by axial slices of the chest phantom. Through the images generated by CT a computational model of voxels of the thorax phantom was developed by SISCODES computational program, being the computational breast phantom represented by the same TE's of the experimental breast phantom. The images generated by CT allowed evaluating the radiological equivalence of the tissues. The breast phantom is being used in studies of experimental dosimetry both in brachytherapy as in teletherapy of breast. Dosimetry studies by MCNP-5 code using the computational model of the phantom breast are in progress. (author)

  20. Computer code validation by high temperature chemistry

    International Nuclear Information System (INIS)

    Alexander, C.A.; Ogden, J.S.

    1988-01-01

    At least five of the computer codes utilized in analysis of severe fuel damage-type events are directly dependent upon or can be verified by high temperature chemistry. These codes are ORIGEN, CORSOR, CORCON, VICTORIA, and VANESA. With the exemption of CORCON and VANESA, it is necessary that verification experiments be performed on real irradiated fuel. For ORIGEN, the familiar knudsen effusion cell is the best choice and a small piece of known mass and known burn-up is selected and volatilized completely into the mass spectrometer. The mass spectrometer is used in the integral mode to integrate the entire signal from preselected radionuclides, and from this integrated signal the total mass of the respective nuclides can be determined. For CORSOR and VICTORIA, experiments with flowing high pressure hydrogen/steam must flow over the irradiated fuel and then enter the mass spectrometer. For these experiments, a high pressure-high temperature molecular beam inlet must be employed. Finally, in support of VANESA-CORCON, the very highest temperature and molten fuels must be contained and analyzed. Results from all types of experiments will be discussed and their applicability to present and future code development will also be covered

  1. Experimental research of the impact of the dosing of chemical reagents on the dynamic behavior of regulation system of cycle chemistry

    Science.gov (United States)

    Yegoshina, O. V.; Bolshakova, N. A.

    2017-11-01

    Organization of reliable chemical control for maintaining cycle chemistry is one of the most important problems to be solved at the present time the design and operation of thermal power plants. To maintain optimal parameters of cycle chemistry are used automated chemical control system and regulation system of dosing chemical reagents. Reliability and stability analyzer readings largely determine the reliability of the water cycle chemistry. Now the most common reagents are ammonia, alkali and film-forming amines. In this paper are presented the results of studies of the impact of concentration and composition of chemical reagents for readings stability of automatic analyzers and transients time of control systems for cycles chemistry. Research of the impact of chemical reagents on the dynamic behavior of regulation system for cycle chemistry was conducted at the experimental facility of the Department of thermal power stations of the Moscow Engineering Institute. This experimental facility is model of the work of regulation system for cycle chemistry close to the actual conditions on the energy facilities CHP. Analysis of results of the impact of chemical reagent on the dynamic behavior of ammonia and film forming amines dosing systems showed that the film-forming amines dosing system is more inertia. This emphasizes the transition process of the system, in which a half times longer dosing of ammonia. Results of the study can be used to improve the monitoring systems of water chemical treatment.

  2. Understanding organometallic reaction mechanisms and catalysis experimental and computational tools computational and experimental tools

    CERN Document Server

    Ananikov, Valentin P

    2014-01-01

    Exploring and highlighting the new horizons in the studies of reaction mechanisms that open joint application of experimental studies and theoretical calculations is the goal of this book. The latest insights and developments in the mechanistic studies of organometallic reactions and catalytic processes are presented and reviewed. The book adopts a unique approach, exemplifying how to use experiments, spectroscopy measurements, and computational methods to reveal reaction pathways and molecular structures of catalysts, rather than concentrating solely on one discipline. The result is a deeper

  3. Handbook of relativistic quantum chemistry

    International Nuclear Information System (INIS)

    Liu, Wenjian

    2017-01-01

    This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.

  4. Factors Affecting Energy Barriers for Pyramidal Inversion in Amines and Phosphines: A Computational Chemistry Lab Exercise

    Science.gov (United States)

    Montgomery, Craig D.

    2013-01-01

    An undergraduate exercise in computational chemistry that investigates the energy barrier for pyramidal inversion of amines and phosphines is presented. Semiempirical calculations (PM3) of the ground-state and transition-state energies for NR[superscript 1]R[superscript 2]R[superscript 3] and PR[superscript 1]R[superscript 2]R[superscript 3] allow…

  5. Computação em química teórica: informações técnicas Computation in theoretical chemistry: technical informations

    Directory of Open Access Journals (Sweden)

    Nelson Henrique Morgon

    2001-10-01

    Full Text Available The purpose of this work is to demonstrate the usefulness of low cost high performance computers. It is presented technics and software packages used by computational chemists. Access to high-performance computing power remains crucial for many computational quantum chemistry. So, this work introduces the concept of PC cluster, an economical computing plataform.

  6. Open Experimentation on Phenomena of Chemical Reactions via the Learning Company Approach in Early Secondary Chemistry Education

    Science.gov (United States)

    Beck, Katharina; Witteck, Torsten; Eilks, Ingo

    2010-01-01

    Presented is a case study on the implementation of open and inquiry-type experimentation in early German secondary chemistry education. The teaching strategy discussed follows the learning company approach. Originally adopted from vocational education, the learning company method is used to redirect lab-oriented classroom practice towards a more…

  7. Computational Modeling of the Optical Rotation of Amino Acids: An "in Silico" Experiment for Physical Chemistry

    Science.gov (United States)

    Simpson, Scott; Autschbach, Jochen; Zurek, Eva

    2013-01-01

    A computational experiment that investigates the optical activity of the amino acid valine has been developed for an upper-level undergraduate physical chemistry laboratory course. Hybrid density functional theory calculations were carried out for valine to confirm the rule that adding a strong acid to a solution of an amino acid in the l…

  8. Handbook of relativistic quantum chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenjian (ed.) [Peking Univ., Beijing (China). Center for Computational Science and Engineering

    2017-03-01

    This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.

  9. Theoretical chemistry in Belgium a topical collection from theoretical chemistry accounts

    CERN Document Server

    Champagne, Benoît; De Proft, Frank; Leyssens, Tom

    2014-01-01

    Readers of this volume can take a tour around the research locations in Belgium which are active in theoretical and computational chemistry. Selected researchers from Belgium present research highlights of their work. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format. This volume will be of benefit in particular to those research groups and libraries that have chosen to have only electronic access to the journal. It also provides valuable content for all researchers in theoretical chemistry.

  10. Recent computational chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Taku [Department of Chemistry for Materials, and The Center of Ultimate Technology on nano-Electronics, Mie University (Japan); Center for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo (Norway)

    2015-12-31

    Now we can investigate quantum phenomena for the real materials and molecules, and can design functional materials by computation, due to the previous developments of quantum theory and calculation methods. As there still exist the limit and problem in theory, the cooperation between theory and computation is getting more important to clarify the unknown quantum mechanism, and discover more efficient functional materials. It would be next-generation standard. Finally, our theoretical methodology for boundary solid is introduced.

  11. Recent computational chemistry

    International Nuclear Information System (INIS)

    Onishi, Taku

    2015-01-01

    Now we can investigate quantum phenomena for the real materials and molecules, and can design functional materials by computation, due to the previous developments of quantum theory and calculation methods. As there still exist the limit and problem in theory, the cooperation between theory and computation is getting more important to clarify the unknown quantum mechanism, and discover more efficient functional materials. It would be next-generation standard. Finally, our theoretical methodology for boundary solid is introduced

  12. The multiple roles of computational chemistry in fragment-based drug design

    Science.gov (United States)

    Law, Richard; Barker, Oliver; Barker, John J.; Hesterkamp, Thomas; Godemann, Robert; Andersen, Ole; Fryatt, Tara; Courtney, Steve; Hallett, Dave; Whittaker, Mark

    2009-08-01

    Fragment-based drug discovery (FBDD) represents a change in strategy from the screening of molecules with higher molecular weights and physical properties more akin to fully drug-like compounds, to the screening of smaller, less complex molecules. This is because it has been recognised that fragment hit molecules can be efficiently grown and optimised into leads, particularly after the binding mode to the target protein has been first determined by 3D structural elucidation, e.g. by NMR or X-ray crystallography. Several studies have shown that medicinal chemistry optimisation of an already drug-like hit or lead compound can result in a final compound with too high molecular weight and lipophilicity. The evolution of a lower molecular weight fragment hit therefore represents an attractive alternative approach to optimisation as it allows better control of compound properties. Computational chemistry can play an important role both prior to a fragment screen, in producing a target focussed fragment library, and post-screening in the evolution of a drug-like molecule from a fragment hit, both with and without the available fragment-target co-complex structure. We will review many of the current developments in the area and illustrate with some recent examples from successful FBDD discovery projects that we have conducted.

  13. Intermediate-energy nuclear chemistry workshop

    International Nuclear Information System (INIS)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities

  14. Intermediate-energy nuclear chemistry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

  15. Exploring Interactive and Dynamic Simulations Using a Computer Algebra System in an Advanced Placement Chemistry Course

    Science.gov (United States)

    Matsumoto, Paul S.

    2014-01-01

    The article describes the use of Mathematica, a computer algebra system (CAS), in a high school chemistry course. Mathematica was used to generate a graph, where a slider controls the value of parameter(s) in the equation; thus, students can visualize the effect of the parameter(s) on the behavior of the system. Also, Mathematica can show the…

  16. Experimental high energy physics and modern computer architectures

    International Nuclear Information System (INIS)

    Hoek, J.

    1988-06-01

    The paper examines how experimental High Energy Physics can use modern computer architectures efficiently. In this connection parallel and vector architectures are investigated, and the types available at the moment for general use are discussed. A separate section briefly describes some architectures that are either a combination of both, or exemplify other architectures. In an appendix some directions in which computing seems to be developing in the USA are mentioned. (author)

  17. Photorefractive and computational holography in the experimental generation of Airy beams

    Science.gov (United States)

    Suarez, Rafael A. B.; Vieira, Tarcio A.; Yepes, Indira S. V.; Gesualdi, Marcos R. R.

    2016-05-01

    In this paper, we present the experimental generation of Airy beams via computational and photorefractive holography. Experimental generation of Airy beams using conventional optical components presents several difficulties and a practically infeasible. Thus, the optical generation of Airy beams has been made from the optical reconstruction of a computer generated hologram implemented by a spatial light modulator. In the photorefractive holography technique, being used for the first time to our knowledge, the hologram of an Airy beam is constructed (recorded) and reconstructed (read) optically in a nonlinear photorefractive medium. The Airy beam experimental realization was made by a setup of computational and photorefractive holography using a photorefractive Bi12 TiO20 crystal as holographic recording medium. Airy beams and Airy beam arrays were obtained experimentally in accordance with the predicted theory; with excellent prospects for applications in optical trapping and optical communications systems.

  18. Química orgânica experimental: integração de teoria, experimento e análise Experimental organic Chemistry: integration of theory, experiment and analysis

    OpenAIRE

    Lothar W. Bieber

    1999-01-01

    A new approach for teaching in basic experimental organic chemistry is presented. Experimental work goes on parallel to theoretical lectures leading to an immediate application of theoretical concepts transmitted therein. One day/week is dedicated exclusively to the organic laboratory. Reactions are proposed as problems to be solved; the student has to deduce the structure of the product on the basis of his observations, the analytical data and his mechanistical knowledge. 70 different experi...

  19. Experimental all-optical one-way quantum computing

    International Nuclear Information System (INIS)

    Prevedel, R.

    2009-01-01

    In recent years, the relatively new field of quantum information processing (QIP) has attracted the attention of many scientists around the world due to its promise of increased computational speed, absolute secure communication and the potential to simulate complex quantum mechanical systems. The very essence of this new quantum information technology are two concepts at the very heart of quantum mechanics, namely superposition and entanglement. The present Thesis contains the results of four different experiments that were all aimed at the demonstration of an entirely new model for quantum computing with linear optics, the 'one-way' quantum computer. For this purpose a multi-photon entangled state of four photons has been generated via the process of spontaneous parametric down-conversion and by using an interferometric setup. This entangled state acts as a resource that allowed for novel demonstrations of quantum algorithms and relevant experimental techniques. By exploiting the advances developed in both theory and experiment, in this Thesis we report the implementation of fast, active feed-forward that allowed, for the first time, the realization of deterministic linear optics quantum computing at an unprecedented speed. Further we were able to demonstrate the Deutsch algorithm on our one-way quantum computer, an important quantum algorithm that is capable of distinguishing whether a function is constant or balanced. Classically one needs to query the algorithm at least 2N/2 + 1 times for an N-bit binary input string, however, in the quantum regime, this can be done with one evaluation of the algorithm, independent of the size of the input. In another experiment we succeeded in playing an instance of a quantum game - the so-called Prisoner's dilemma - on our one-way quantum computer. Playing such a game is essentially the execution of a quantum algorithm made up of a distinct set of one- and two-qubit gates. This allows the individual players to increase their

  20. Introductory Molecular Orbital Theory: An Honors General Chemistry Computational Lab as Implemented Using Three-Dimensional Modeling Software

    Science.gov (United States)

    Ruddick, Kristie R.; Parrill, Abby L.; Petersen, Richard L.

    2012-01-01

    In this study, a computational molecular orbital theory experiment was implemented in a first-semester honors general chemistry course. Students used the GAMESS (General Atomic and Molecular Electronic Structure System) quantum mechanical software (as implemented in ChemBio3D) to optimize the geometry for various small molecules. Extended Huckel…

  1. Integration of Computational and Preparative Techniques to Demonstrate Physical Organic Concepts in Synthetic Organic Chemistry: An Example Using Diels-Alder Reaction

    Science.gov (United States)

    Palmer, David R. J.

    2004-01-01

    The Diels-Alder reaction is used as an example for showing the integration of computational and preparative techniques, which help in demonstrating the physical organic concepts in synthetic organic chemistry. These experiments show that the students should not accept the computational results without questioning them and in many Diels-Alder…

  2. The Importance of Computer Based Active Learning for Basic Chemistry in Vocational High Schools

    Directory of Open Access Journals (Sweden)

    Tuğçe GÜNTER

    2011-01-01

    Full Text Available Chemistry is a very comprehensive discipline that researches atoms; molecules; the structure of matter in the form of element or compound; combinations, and physical and chemical properties of matter; macroscopic and microscopic transformations of matters; the energy and entropy released or absorbed in the course of these transformations; the structures and functions of carbohydrates, lipids, proteins, enzymes, vitamins and minerals in the body. This discipline includes numerous reactions at the macroscopic, microscopic and particulate levels, abstract concepts, three-dimensional structure of molecules, mathematics, and graphics. It is important for students to be trained as scientists to internalize -with meaningful learning - chemistry having much abstract concepts. Especially for students in associate degree programs in Vocational High Schools, taking this integrated course will provide them to be more creative in their future professional work; to cope with and overcome analytical problems; to be self-learners; to fill the gaps concerning chemical analysis originated from secondary education; and to gain critical thinking and self-evaluation skills regarding chemical problems. In the age of developing science and technology, “Computer-Based Active Learning Method” emerged with the introduction of multi-media into education and training. In this context, students will learn difficult and complex mathematical operations and graphics interpretations more meaningfully with computer-based simulations and analogies.

  3. Mass spectrometry. [in organic chemistry

    Science.gov (United States)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

    1978-01-01

    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  4. Dissociative properties of 1,1,1,2-tetrafluoroethane obtained by computational chemistry

    Science.gov (United States)

    Hayashi, Toshio; Ishikawa, Kenji; Sekine, Makoto; Hori, Masaru

    2018-06-01

    The electronic properties and dissociative channels of the alternative to the CCl2F2 (CFC-12) refrigerant, 1,1,1,2-tetrafluoroethane (HFC-134a) with a low global warming potential (GWP, 1430), were revealed by computational chemistry. The results show that CF3 + and CHF2 + ions are mainly produced by ionization. The CF3CH2 + ion is produced by ion pair formation and by direct ionization in the energy region higher than approximately 15 eV, but also in small amounts by the ionization of the dissociated CF3CH2 radical. This information is useful for etching process engineers in leading-edge semiconductor manufacturing.

  5. Extraction of pigments from seeds of Bixa orellana L.: an alternative for experimental courses in organic chemistry

    International Nuclear Information System (INIS)

    Costa, Charllyton Luis S. da; Chaves, Mariana H.

    2005-01-01

    This paper describes methodologies for the extraction and characterization by TLC, UV-VIS, IR and NMR of bixin from Bixa orellana L. (urucum) seeds. Based on the results, the extraction with NaOH 5% is the fastest, uses low cost materials, requires two to four laboratory hours and is a useful alternative for an experimental Organic Chemistry discipline. (author)

  6. Optimizing qubit resources for quantum chemistry simulations in second quantization on a quantum computer

    International Nuclear Information System (INIS)

    Moll, Nikolaj; Fuhrer, Andreas; Staar, Peter; Tavernelli, Ivano

    2016-01-01

    Quantum chemistry simulations on a quantum computer suffer from the overhead needed for encoding the Fermionic problem in a system of qubits. By exploiting the block diagonality of a Fermionic Hamiltonian, we show that the number of required qubits can be reduced while the number of terms in the Hamiltonian will increase. All operations for this reduction can be performed in operator space. The scheme is conceived as a pre-computational step that would be performed prior to the actual quantum simulation. We apply this scheme to reduce the number of qubits necessary to simulate both the Hamiltonian of the two-site Fermi–Hubbard model and the hydrogen molecule. Both quantum systems can then be simulated with a two-qubit quantum computer. Despite the increase in the number of Hamiltonian terms, the scheme still remains a useful tool to reduce the dimensionality of specific quantum systems for quantum simulators with a limited number of resources. (paper)

  7. Aqueous chemistry of transactinides

    International Nuclear Information System (INIS)

    Schaedel, M.

    2001-01-01

    The aqueous chemistry of the first three transactinide elements is briefly reviewed with special emphasis given to recent experimental results. Short introductory remarks are discussing the atom-at-a-time situation of transactinide chemistry as a result of low production cross-sections and short half-lives. In general, on-line experimental techniques and, more specifically, the automated rapid chemistry apparatus, ARCA, are presented. Present and future developments of experimental techniques and resulting perspectives are outlined at the end. The central part is mainly focussing on hydrolysis and complex formation aspects of the superheavy group 4, 5, and 6 transition metals with F - and Cl - anions. Experimental results are compared with the behaviour of lighter homologous elements and with relativistic calculations. It will be shown that the chemical behaviour of the first superheavy elements is already strongly influenced by relativistic effects. While it is justified to place rutherfordium, dubnium and seaborgium in the Periodic Table of the Elements into group 4, 5 and 6, respectively, it is no more possible to deduce from this position in detail the chemical properties of these transactinide or superheavy elements. (orig.)

  8. MIANN models in medicinal, physical and organic chemistry.

    Science.gov (United States)

    González-Díaz, Humberto; Arrasate, Sonia; Sotomayor, Nuria; Lete, Esther; Munteanu, Cristian R; Pazos, Alejandro; Besada-Porto, Lina; Ruso, Juan M

    2013-01-01

    Reducing costs in terms of time, animal sacrifice, and material resources with computational methods has become a promising goal in Medicinal, Biological, Physical and Organic Chemistry. There are many computational techniques that can be used in this sense. In any case, almost all these methods focus on few fundamental aspects including: type (1) methods to quantify the molecular structure, type (2) methods to link the structure with the biological activity, and others. In particular, MARCH-INSIDE (MI), acronym for Markov Chain Invariants for Networks Simulation and Design, is a well-known method for QSAR analysis useful in step (1). In addition, the bio-inspired Artificial-Intelligence (AI) algorithms called Artificial Neural Networks (ANNs) are among the most powerful type (2) methods. We can combine MI with ANNs in order to seek QSAR models, a strategy which is called herein MIANN (MI & ANN models). One of the first applications of the MIANN strategy was in the development of new QSAR models for drug discovery. MIANN strategy has been expanded to the QSAR study of proteins, protein-drug interactions, and protein-protein interaction networks. In this paper, we review for the first time many interesting aspects of the MIANN strategy including theoretical basis, implementation in web servers, and examples of applications in Medicinal and Biological chemistry. We also report new applications of the MIANN strategy in Medicinal chemistry and the first examples in Physical and Organic Chemistry, as well. In so doing, we developed new MIANN models for several self-assembly physicochemical properties of surfactants and large reaction networks in organic synthesis. In some of the new examples we also present experimental results which were not published up to date.

  9. A computational glance at organometallic cyclizations and coupling reactions

    OpenAIRE

    Fiser, Béla

    2016-01-01

    210 p. Organometallic chemistry is one of the main research topics in chemical science.Nowadays, organometallic reactions are the subject of intensive theoretical investigations.However, in many cases, only joint experimental and theoretical effortscould reveal the answers what we are looking for.The fruits of such experimental and theoretical co-operations will be presentedhere. In this work, we are going to deal with homogeneous organometallic catalysisusing computational chemical tools....

  10. XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Summary of reports

    International Nuclear Information System (INIS)

    2011-01-01

    The collection contains materials of plenary, sectional and poster sessions, presented at the XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Theoretical questions and new experimental methods of chemistry of solutions, structure and dynamics of molecular and ion-molecular systems in solution and at the phase boundary; modern aspects of applied chemistry of solutions are discussed [ru

  11. Phase behavior of multicomponent membranes: Experimental and computational techniques

    DEFF Research Database (Denmark)

    Bagatolli, Luis; Kumar, P.B. Sunil

    2009-01-01

    Recent developments in biology seems to indicate that the Fluid Mosaic model of membrane proposed by Singer and Nicolson, with lipid bilayer functioning only as medium to support protein machinery, may be too simple to be realistic. Many protein functions are now known to depend on the compositio....... This review includes basic foundations on membrane model systems and experimental approaches applied in the membrane research area, stressing on recent advances in the experimental and computational techniques....... membranes. Current increase in interest in the domain formation in multicomponent membranes also stems from the experiments demonstrating liquid ordered-liquid disordered coexistence in mixtures of lipids and cholesterol and the success of several computational models in predicting their behavior...

  12. Web-based computational chemistry education with CHARMMing II: Coarse-grained protein folding.

    Directory of Open Access Journals (Sweden)

    Frank C Pickard

    2014-07-01

    Full Text Available A lesson utilizing a coarse-grained (CG Gō-like model has been implemented into the CHARMM INterface and Graphics (CHARMMing web portal (www.charmming.org to the Chemistry at HARvard Macromolecular Mechanics (CHARMM molecular simulation package. While widely used to model various biophysical processes, such as protein folding and aggregation, CG models can also serve as an educational tool because they can provide qualitative descriptions of complex biophysical phenomena for a relatively cheap computational cost. As a proof of concept, this lesson demonstrates the construction of a CG model of a small globular protein, its simulation via Langevin dynamics, and the analysis of the resulting data. This lesson makes connections between modern molecular simulation techniques and topics commonly presented in an advanced undergraduate lecture on physical chemistry. It culminates in a straightforward analysis of a short dynamics trajectory of a small fast folding globular protein; we briefly describe the thermodynamic properties that can be calculated from this analysis. The assumptions inherent in the model and the data analysis are laid out in a clear, concise manner, and the techniques used are consistent with those employed by specialists in the field of CG modeling. One of the major tasks in building the Gō-like model is determining the relative strength of the nonbonded interactions between coarse-grained sites. New functionality has been added to CHARMMing to facilitate this process. The implementation of these features into CHARMMing helps automate many of the tedious aspects of constructing a CG Gō model. The CG model builder and its accompanying lesson should be a valuable tool to chemistry students, teachers, and modelers in the field.

  13. Application of computational chemistry methods to obtain thermodynamic data for hydrogen production from liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    J. A. Sousa

    2013-03-01

    Full Text Available The objective of this study was to estimate thermodynamic data, such as standard enthalpy, entropy and Gibbs free energy changes of reaction and, consequently, chemical equilibrium constants, for a reaction system describing the hydrogen production from Liquefied Petroleum Gas (LPG. The acquisition of those properties was made using computational chemistry methods and the results were compared with experimental data reported in the literature. The reaction system of steam reforming of LPG was reported as a set of seven independent reactions involving the chemical species n-C4H10, C3H8, C2H6, C2H4, CH4, CO2, CO, H2O, H2 and solid carbon. Six computational approaches were used: Density Functional Theory (DFT employing Becke's three parameter hybrid exchange functional, and the Lee-Yang-Parr correlation functional (B3LYP using the 6-31G++(d,p basis set and the composite methods CBS-QB3, Gaussian-1 (G1, Gaussian-2 (G2, Gaussian-3 (G3 and Gaussian-4 (G4. Mole fractions of the system components were also determined between 873.15 and 1173.15 K, at 1 atm and a feed with a stoichiometric amount of water. Results showed that the hybrid functional B3LYP/6-31G++(d,p, G3 and G4 theories were the most appropriated methods to predict the properties of interest. Gaussian-3 and Gaussian-4 theories are expected to be good thermodynamic data predictors and the known efficient prediction of vibrational frequencies by B3LYP is probably the source of the good agreement found in this study. This last methodology is of special interest since it presents low computational cost, which is important when more complex molecular systems are considered.

  14. Revisiting dibenzothiophene thermochemical data: Experimental and computational studies

    International Nuclear Information System (INIS)

    Freitas, Vera L.S.; Gomes, Jose R.B.; Ribeiro da Silva, Maria D.M.C.

    2009-01-01

    Thermochemical data of dibenzothiophene were studied in the present work by experimental techniques and computational calculations. The standard (p 0 =0.1MPa) molar enthalpy of formation, at T = 298.15 K, in the gaseous phase, was determined from the enthalpy of combustion and sublimation, obtained by rotating bomb calorimetry in oxygen, and by Calvet microcalorimetry, respectively. This value was compared with estimated data from G3(MP2)//B3LYP computations and also with the other results available in the literature.

  15. Pharmacokinetic study with computational tools in the medicinal chemistry course

    Directory of Open Access Journals (Sweden)

    Monique Araújo de Brito

    2011-12-01

    Full Text Available To improve the teaching-learning process in the Medicinal Chemistry course, new strategies have been incorporated into practical classes of this fundamental discipline of the pharmaceutical curriculum. Many changes and improvements have been made in the area of medicinal chemistry so far, and students should be prepared for these new approaches with the use of technological resources in this field. Practical activities using computational techniques have been directed to the evaluation of chemical and physicochemical properties that affect the pharmacokinetics of drugs. Their objectives were to allow students to know these tools, to learn how to access them, to search for the structures of drugs and to analyze results. To the best of our knowledge, this is the first study in Brazil to demonstrate the use of computational practices in teaching pharmacokinetics. Practical classes using Osiris and Molinspiration were attractive to students, who developed the activities easily and acquired better theoretical knowledge.Para melhorar o processo ensino-aprendizagem no curso de Química Medicinal novas estratégias estão sendo incorporadas às aulas práticas desta disciplina fundamental do currículo farmacêutico. Muitas mudanças e melhorias vêm marcando a área de química medicinal e por isso é importante que os alunos sejam colocados nestas novas abordagens na área, com a utilização de recursos tecnológicos. As atividades práticas foram direcionadas para a avaliação dos dados químicos e físico-químicos de fármacos que influenciam as propriedades farmacocinéticas com o auxílio de técnicas computacionais. Os objetivos foram permitir aos alunos conhecer essas ferramentas, saber como acessá-las, procurar as estruturas de fármacos e analisar os resultados. Este é o primeiro estudo publicado no Brasil que apresenta aula prática computacional sobre o tema farmacocinética. As aulas práticas utilizando os servidores Osiris e

  16. Analytical chemistry

    International Nuclear Information System (INIS)

    Choi, Jae Seong

    1993-02-01

    This book is comprised of nineteen chapters, which describes introduction of analytical chemistry, experimental error and statistics, chemistry equilibrium and solubility, gravimetric analysis with mechanism of precipitation, range and calculation of the result, volume analysis on general principle, sedimentation method on types and titration curve, acid base balance, acid base titration curve, complex and firing reaction, introduction of chemical electro analysis, acid-base titration curve, electrode and potentiometry, electrolysis and conductometry, voltammetry and polarographic spectrophotometry, atomic spectrometry, solvent extraction, chromatograph and experiments.

  17. Analytical chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Seong

    1993-02-15

    This book is comprised of nineteen chapters, which describes introduction of analytical chemistry, experimental error and statistics, chemistry equilibrium and solubility, gravimetric analysis with mechanism of precipitation, range and calculation of the result, volume analysis on general principle, sedimentation method on types and titration curve, acid base balance, acid base titration curve, complex and firing reaction, introduction of chemical electro analysis, acid-base titration curve, electrode and potentiometry, electrolysis and conductometry, voltammetry and polarographic spectrophotometry, atomic spectrometry, solvent extraction, chromatograph and experiments.

  18. The synergistic use of computation, chemistry and biology to discover novel peptide-based drugs: the time is right.

    Science.gov (United States)

    Audie, J; Boyd, C

    2010-01-01

    The case for peptide-based drugs is compelling. Due to their chemical, physical and conformational diversity, and relatively unproblematic toxicity and immunogenicity, peptides represent excellent starting material for drug discovery. Nature has solved many physiological and pharmacological problems through the use of peptides, polypeptides and proteins. If nature could solve such a diversity of challenging biological problems through the use of peptides, it seems reasonable to infer that human ingenuity will prove even more successful. And this, indeed, appears to be the case, as a number of scientific and methodological advances are making peptides and peptide-based compounds ever more promising pharmacological agents. Chief among these advances are powerful chemical and biological screening technologies for lead identification and optimization, methods for enhancing peptide in vivo stability, bioavailability and cell-permeability, and new delivery technologies. Other advances include the development and experimental validation of robust computational methods for peptide lead identification and optimization. Finally, scientific analysis, biology and chemistry indicate the prospect of designing relatively small peptides to therapeutically modulate so-called 'undruggable' protein-protein interactions. Taken together a clear picture is emerging: through the synergistic use of the scientific imagination and the computational, chemical and biological methods that are currently available, effective peptide therapeutics for novel targets can be designed that surpass even the proven peptidic designs of nature.

  19. On the Impact of Execution Models: A Case Study in Computational Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Chavarría-Miranda, Daniel; Halappanavar, Mahantesh; Krishnamoorthy, Sriram; Manzano Franco, Joseph B.; Vishnu, Abhinav; Hoisie, Adolfy

    2015-05-25

    Efficient utilization of high-performance computing (HPC) platforms is an important and complex problem. Execution models, abstract descriptions of the dynamic runtime behavior of the execution stack, have significant impact on the utilization of HPC systems. Using a computational chemistry kernel as a case study and a wide variety of execution models combined with load balancing techniques, we explore the impact of execution models on the utilization of an HPC system. We demonstrate a 50 percent improvement in performance by using work stealing relative to a more traditional static scheduling approach. We also use a novel semi-matching technique for load balancing that has comparable performance to a traditional hypergraph-based partitioning implementation, which is computationally expensive. Using this study, we found that execution model design choices and assumptions can limit critical optimizations such as global, dynamic load balancing and finding the correct balance between available work units and different system and runtime overheads. With the emergence of multi- and many-core architectures and the consequent growth in the complexity of HPC platforms, we believe that these lessons will be beneficial to researchers tuning diverse applications on modern HPC platforms, especially on emerging dynamic platforms with energy-induced performance variability.

  20. Enhancing prospective chemistry teachers cognitive structures in the topics of bonding and hybridization by internet-assisted chemistry applications

    OpenAIRE

    Özge Özyalçın Oskay, Sinem Dinçol

    2011-01-01

    The purpose of this study is to determine the effects of internet-assisted chemistry applications on prospective chemistry teachers’ cognitive structures in the topics of bonding and hybridization. The sample of the study consisted of 36 prospective chemistry teachers attending Hacettepe University, Faculty of Education, the Department of Chemistry Education in 2010-2011 academic year and taking Basic Chemistry I lesson. In the study, students were separated into experimental and control gr...

  1. Statistical Methodologies to Integrate Experimental and Computational Research

    Science.gov (United States)

    Parker, P. A.; Johnson, R. T.; Montgomery, D. C.

    2008-01-01

    Development of advanced algorithms for simulating engine flow paths requires the integration of fundamental experiments with the validation of enhanced mathematical models. In this paper, we provide an overview of statistical methods to strategically and efficiently conduct experiments and computational model refinement. Moreover, the integration of experimental and computational research efforts is emphasized. With a statistical engineering perspective, scientific and engineering expertise is combined with statistical sciences to gain deeper insights into experimental phenomenon and code development performance; supporting the overall research objectives. The particular statistical methods discussed are design of experiments, response surface methodology, and uncertainty analysis and planning. Their application is illustrated with a coaxial free jet experiment and a turbulence model refinement investigation. Our goal is to provide an overview, focusing on concepts rather than practice, to demonstrate the benefits of using statistical methods in research and development, thereby encouraging their broader and more systematic application.

  2. Convection and chemistry effects in CVD: A 3-D analysis for silicon deposition

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.; Tsui, P.; Chait, A.

    1989-01-01

    The computational fluid dynamics code FLUENT has been adopted to simulate the entire rectangular-channel-like (3-D) geometry of an experimental CVD reactor designed for Si deposition. The code incorporated the effects of both homogeneous (gas phase) and heterogeneous (surface) chemistry with finite reaction rates of important species existing in silane dissociation. The experiments were designed to elucidate the effects of gravitationally-induced buoyancy-driven convection flows on the quality of the grown Si films. This goal is accomplished by contrasting the results obtained from a carrier gas mixture of H2/Ar with the ones obtained from the same molar mixture ratio of H2/He, without any accompanying change in the chemistry. Computationally, these cases are simulated in the terrestrial gravitational field and in the absence of gravity. The numerical results compare favorably with experiments. Powerful computational tools provide invaluable insights into the complex physicochemical phenomena taking place in CVD reactors. Such information is essential for the improved design and optimization of future CVD reactors.

  3. Integrating UNESCO ICT-Based Instructional Materials in Chemistry Lessons

    Directory of Open Access Journals (Sweden)

    CHARLIE P. NACARIO

    2014-08-01

    Full Text Available This study determined the effectiveness of the lessons in Chemistry integrating UNESCO ICT-based instructional material on the achievement of Chemistry students at Central Bicol State University of Agriculture. It aimed to identify lessons that may be developed integrating UNESCO ICT-based instructional materials, determine the effect of the developed lessons using the material on: conceptual understanding; science process skills; and attitude towards chemistry and gather insights from the experiences of the students and teacher. The study used the single group pretest and posttest experimental design. Descriptive, quantitative and qualitative techniques were also utilized. Quantitative data were taken from the pretest-posttest results on the Test on Conceptual Understanding, Science Process Skills and Chemistry Attitudinaire. Qualitative data were drawn from the experts’ assessment of the developed lessons and research instruments, and the insights of students and teacher. The developed lessons integrating UNESCO ICT-based instructional materials were Atomic Model and Structure, Periodic Table of Elements, Chemical Bonding, and Balancing Chemical Equation. These lessons increased the conceptual understanding of the students by topic and skill from very low mastery to average mastery level. The students have slightly improved along the different science process skills. After teaching the lessons, the students’ attitude also improved. The students became more motivated and interested in Chemistry and the lessons were student centered and entailed teacher’s competence and flexibility in computer use.

  4. A report on intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwater

    International Nuclear Information System (INIS)

    Broyd, T.W.; McD Grant, M.; Cross, J.E.

    1985-01-01

    This report describes two intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwaters. These studies have been performed by running a series of test cases with each program and comparing the various results obtained. The work forms a part of the CEC MIRAGE project (MIgration of RAdionuclides in the GEosphere) and has been jointly funded by the CEC and the United Kingdom Department of the Environment. Presentations of the material contained herein were given at plenary meetings of the MIRAGE project in Brussels in March, 1984 (migration) and March, 1985 (equilibrium chemistry) respectively

  5. Harmony of computational quantum chemistry and experimental chemistry: Comprehensive DFT studies, microsynthesis, and characterization of mustard gas polysulfide analogues

    Science.gov (United States)

    Saeidian, Hamid; Faraz, Sajjad Mousavi; Mirjafary, Zohreh; Babri, Mehran

    2018-05-01

    After microsynthesis, structures of mustard gas polysulfide analogues were characterized using electron impact (EI) mass spectrometry. General EI fragmentation pathways for such compounds are proposed. The structure of sulfur mustard (HD) and its two other polysulfide analogues have been examined through B3LYP/6-311++G(2d, 2p) calculations. Geometrical analysis of HD shows that the calculated bond distances are satisfactorily comparable with experimental results. Calculated NMR chemical shifts for HD also were compared with experimental data, indicating good agreement both for 1H and 13C atoms. The vibrational frequencies of HD and polysulfide analogues have been precisely assigned. At the end, based on visual inspection of lowest unoccupied molecular orbitals and the relative difference in the total energies of their episulfonium ions, relative reactivity of HD and its polysulfide analogues were investigated.

  6. User's guide for vectorized code EQUIL for calculating equilibrium chemistry on Control Data STAR-100 computer

    Science.gov (United States)

    Kumar, A.; Graves, R. A., Jr.; Weilmuenster, K. J.

    1980-01-01

    A vectorized code, EQUIL, was developed for calculating the equilibrium chemistry of a reacting gas mixture on the Control Data STAR-100 computer. The code provides species mole fractions, mass fractions, and thermodynamic and transport properties of the mixture for given temperature, pressure, and elemental mass fractions. The code is set up for the electrons H, He, C, O, N system of elements. In all, 24 chemical species are included.

  7. Experimental and modelling studies of the near-field chemistry for Nirex repository concepts

    International Nuclear Information System (INIS)

    Atkinson, A.; Ewart, F.T.; Pugh, S.Y.R.; Rees, J.H.; Sharland, S.M.; Tasker, P.W.; Wilkins, J.D.

    1988-02-01

    A research programme is described which is designed to investigate the chemical conditions in the near field of a concrete based repository and the behaviour of the radiologically important nuclides under these conditions. The chemical conditions are determined by the corrosion of the iron components of the repository and by the soluble components of the concrete. Both of these have been investigated experimentally and models developed which have been validated by further experiment. The effect of these reactions on the repository pH and Eh, and how these develop in time and space have been modelled using a coupled chemical equilibrium and transport code. The solubility of the important nuclides are being studied experimentally under these conditions, and under sensible variations. These data have been used to refine the thermodynamic data base used for the geochemical code PHREEQE. The sorption behaviour of plutonium and americium, under the same conditions, have been studied; the sorption coefficients were found to be large and independent of the concrete formulation, particle size and solid liquid ratio. Recent experimental results from sorption/exchange experiments with lead and 14-carbon are also reported. The programme has also investigated experimentally the possible perturbation of the repository chemistry by microbial action and by natural and added organic material. A final set of experiments combine all the repository components and the waste in a long term equilibration experiment. (author)

  8. Using Computational Chemistry Activities to Promote Learning and Retention in a Secondary School General Chemistry Setting

    Science.gov (United States)

    Ochterski, Joseph W.

    2014-01-01

    This article describes the results of using state-of-the-art, research-quality software as a learning tool in a general chemistry secondary school classroom setting. I present three activities designed to introduce fundamental chemical concepts regarding molecular shape and atomic orbitals to students with little background in chemistry, such as…

  9. PREDICTING CHEMICAL REACTIVITY OF HUMIC SUBSTANCES FOR MINERALS AND XENOBIOTICS: USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY AND VIRTUAL REALITY

    Science.gov (United States)

    In this chapter we review the literature on scanning probe microscopy (SPM), virtual reality (VR), and computational chemistry and our earlier work dealing with modeling lignin, lignin-carbohydrate complexes (LCC), humic substances (HSs) and non-bonded organo-mineral interactions...

  10. Real-time prediction of Physicochemical and Toxicological Endpoints Using the Web-based CompTox Chemistry Dashboard (ACS Fall meeting) 10 of 12

    Science.gov (United States)

    The EPA CompTox Chemistry Dashboard developed by the National Center for Computational Toxicology (NCCT) provides access to data for ~750,000 chemical substances. The data include experimental and predicted data for physicochemical, environmental fate and transport and toxicologi...

  11. Experiments in physical chemistry

    CERN Document Server

    Wilson, J M; Denaro, A R

    1968-01-01

    Experiments in Physical Chemistry, Second Edition provides a compilation of experiments concerning physical chemistry. This book illustrates the link between the theory and practice of physical chemistry. Organized into three parts, this edition begins with an overview of those experiments that generally have a simple theoretical background. Part II contains experiments that are associated with more advanced theory or more developed techniques, or which require a greater degree of experimental skill. Part III consists of experiments that are in the nature of investigations wherein these invest

  12. Experimental data processing techniques by a personal computer

    International Nuclear Information System (INIS)

    Matsuura, Kiyokata; Tsuda, Kenzo; Abe, Yoshihiko; Kojima, Tsuyoshi; Nishikawa, Akira; Shimura, Hitoshi; Hyodo, Hiromi; Yamagishi, Shigeru.

    1989-01-01

    A personal computer (16-bit, about 1 MB memory) can be used at a low cost in the experimental data processing. This report surveys the important techniques on A/D and D/A conversion, display, store and transfer of the experimental data. It is also discussed the items to be considered in the software. Practical softwares programed BASIC and Assembler language are given as examples. Here, we present some techniques to get faster process in BASIC language and show that the system composed of BASIC and Assembler is useful in a practical experiment. The system performance such as processing speed and flexibility in setting operation condition will depend strongly on programming language. We have made test for processing speed by some typical programming languages; BASIC(interpreter), C, FORTRAN and Assembler. As for the calculation, FORTRAN has the best performance which is comparable to or better than Assembler even in the personal computer. (author)

  13. Distributed computing testbed for a remote experimental environment

    International Nuclear Information System (INIS)

    Butner, D.N.; Casper, T.A.; Howard, B.C.; Henline, P.A.; Davis, S.L.; Barnes, D.

    1995-01-01

    Collaboration is increasing as physics research becomes concentrated on a few large, expensive facilities, particularly in magnetic fusion energy research, with national and international participation. These facilities are designed for steady state operation and interactive, real-time experimentation. We are developing tools to provide for the establishment of geographically distant centers for interactive operations; such centers would allow scientists to participate in experiments from their home institutions. A testbed is being developed for a Remote Experimental Environment (REE), a ''Collaboratory.'' The testbed will be used to evaluate the ability of a remotely located group of scientists to conduct research on the DIII-D Tokamak at General Atomics. The REE will serve as a testing environment for advanced control and collaboration concepts applicable to future experiments. Process-to-process communications over high speed wide area networks provide real-time synchronization and exchange of data among multiple computer networks, while the ability to conduct research is enhanced by adding audio/video communication capabilities. The Open Software Foundation's Distributed Computing Environment is being used to test concepts in distributed control, security, naming, remote procedure calls and distributed file access using the Distributed File Services. We are exploring the technology and sociology of remotely participating in the operation of a large scale experimental facility

  14. Physics, radiology, and chemistry. 7. rev. ed.

    International Nuclear Information System (INIS)

    Linde, O.K.; Knigge, H.J.

    1986-01-01

    This book is an introduction to physics and chemistry especially for medical personnel. After a general introduction, measurement methods, mechanics including mechanics of solid bodies, fluids and gases, heat, optics, acoustics, electricity, radiations including their biological effects, general chemistry, inorganic and organic chemistry are treated. Every chapter contains exercises mostly in connection with medical and biological effects. Furthermore, connections with biology and medicine are considered. The chapters on physiological chemistry, computer and information theory, chemistry and ecology, and metabolism have been rewritten. (orig./HP) [de

  15. Experimental investigation of liquid chromatography columns by means of computed tomography

    DEFF Research Database (Denmark)

    Astrath, D.U.; Lottes, F.; Vu, Duc Thuong

    2007-01-01

    The efficiency of packed chromatographic columns was investigated experimentally by means of computed tomography (CT) techniques. The measurements were carried out by monitoring tracer fronts in situ inside the chromatographic columns. The experimental results were fitted using the equilibrium di...

  16. Combined use of computational chemistry and chemoinformatics methods for chemical discovery

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Manabu, E-mail: sugimoto@kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan); Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ideo, Toshihiro; Iwane, Ryo [Graduate School of Science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan)

    2015-12-31

    Data analysis on numerical data by the computational chemistry calculations is carried out to obtain knowledge information of molecules. A molecular database is developed to systematically store chemical, electronic-structure, and knowledge-based information. The database is used to find molecules related to a keyword of “cancer”. Then the electronic-structure calculations are performed to quantitatively evaluate quantum chemical similarity of the molecules. Among the 377 compounds registered in the database, 24 molecules are found to be “cancer”-related. This set of molecules includes both carcinogens and anticancer drugs. The quantum chemical similarity analysis, which is carried out by using numerical results of the density-functional theory calculations, shows that, when some energy spectra are referred to, carcinogens are reasonably distinguished from the anticancer drugs. Therefore these spectral properties are considered of as important measures for classification.

  17. The experimental modification of a computer software package for ...

    African Journals Online (AJOL)

    The experimental modification of a computer software package for graphing algebraic functions. ... No Abstract Available South African Journal of Education Vol.25(2) 2005: 61-68. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  18. From trace chemistry to single atom chemistry

    International Nuclear Information System (INIS)

    Adloff, J.P.

    1993-01-01

    Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

  19. Experimental and Computational Investigation of Triple-rotating Blades in a Mower Deck

    Science.gov (United States)

    Chon, Woochong; Amano, Ryoichi S.

    Experimental and computational studies were performed on the 1.27m wide three-spindle lawn mower deck with side discharge arrangement. Laser Doppler Velocimetry was used to measure the air velocity at 12 different sections under the mower deck. The high-speed video camera test provided valuable visual evidence of airflow and grass discharge patterns. The strain gages were attached at several predetermined locations of the mower blades to measure the strain. In computational fluid dynamics work, computer based analytical studies were performed. During this phase of work, two different trials were attempted. First, two-dimensional blade shapes at several arbitrary radial sections were selected for flow computations around the blade model. Finally, a three-dimensional full deck model was developed and compared with the experimental results.

  20. Effect of Computer-Based Video Games on Children: An Experimental Study

    Science.gov (United States)

    Chuang, Tsung-Yen; Chen, Wei-Fan

    2009-01-01

    This experimental study investigated whether computer-based video games facilitate children's cognitive learning. In comparison to traditional computer-assisted instruction (CAI), this study explored the impact of the varied types of instructional delivery strategies on children's learning achievement. One major research null hypothesis was…

  1. Thermodynamic properties of indan: Experimental and computational results

    International Nuclear Information System (INIS)

    Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.

    2016-01-01

    Highlights: • Heat capacities were measured for the temperature range (5 to 445) K. • Vapor pressures were measured for the temperature range (338 to 495) K. • Densities at saturation pressure were measured from T = (323 to 523) K. • Computed and experimentally derived properties for ideal gas entropies are in excellent accord. • Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for indan (Chemical Abstracts registry number [496-11-7], 2,3-dihydro-1H-indene) are reported. Experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry, comparative ebulliometry, and vibrating-tube densitometry. Molar thermodynamic functions (enthalpies, entropies, and Gibbs energies) for the condensed and ideal-gas states were derived from the experimental studies at selected temperatures. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d, p) level of theory. Computed ideal-gas properties derived with the rigid-rotor harmonic-oscillator approximation are shown to be in excellent accord with ideal-gas entropies derived from thermophysical property measurements of this research, as well as with experimental heat capacities for the ideal-gas state reported in the literature. Literature spectroscopic studies and ab initio calculations report a range of values for the barrier to ring puckering. Results of the present work are consistent with a large barrier that allows use of the rigid-rotor harmonic-oscillator approximation for ideal-gas entropy and heat-capacity calculations, even with the stringent uncertainty requirements imposed by the calorimetric and physical property measurements reported here. All experimental results are compared with property values reported in the literature.

  2. Computational Modelling of Patella Femoral Kinematics During Gait Cycle and Experimental Validation

    Science.gov (United States)

    Maiti, Raman

    2016-06-01

    The effect of loading and boundary conditions on patellar mechanics is significant due to the complications arising in patella femoral joints during total knee replacements. To understand the patellar mechanics with respect to loading and motion, a computational model representing the patella femoral joint was developed and validated against experimental results. The computational model was created in IDEAS NX and simulated in MSC ADAMS/VIEW software. The results obtained in the form of internal external rotations and anterior posterior displacements for a new and experimentally simulated specimen for patella femoral joint under standard gait condition were compared with experimental measurements performed on the Leeds ProSim knee simulator. A good overall agreement between the computational prediction and the experimental data was obtained for patella femoral kinematics. Good agreement between the model and the past studies was observed when the ligament load was removed and the medial lateral displacement was constrained. The model is sensitive to ±5 % change in kinematics, frictional, force and stiffness coefficients and insensitive to time step.

  3. Experimentally calibrated computational chemistry of tryptophan hydroxylase: Trans influence, hydrogen-bonding, and 18-electron rule govern O-2-activation

    DEFF Research Database (Denmark)

    Haahr, Lærke Tvedebrink; Kepp, Kasper Planeta; Boesen, Jane

    2010-01-01

    with the experimental value (0.25 mm/s) which we propose as the structure of the hydroxylating intermediate, with the tryptophan substrate well located for further reaction 3.5 Å from the ferryl group. Based on the optimized transition states, the activation barriers for the two paths (glu and his) are similar, so......Insight into the nature of oxygen activation in tryptophan hydroxylase has been obtained from density functional computations. Conformations of O2-bound intermediates have been studied with oxygen trans to glutamate and histidine, respectively. An O2-adduct with O2 trans to histidine (Ohis...... towards the cofactor and a more activated O–O bond (1.33 Å) than in Oglu (1.30 Å). It is shown that the cofactor can hydrogen bond to O2 and activate the O–O bond further (from 1.33 to 1.38 Å). The Ohis intermediate leads to a ferryl intermediate (Fhis) with an isomer shift of 0.34 mm/s, also consistent...

  4. Computational Design and Experimental Validation of New Thermal Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin; Yang, Shizhong; Khosravi, Ebrahim

    2011-12-31

    This project (10/01/2010-9/30/2013), “Computational Design and Experimental Validation of New Thermal Barrier Systems”, originates from Louisiana State University (LSU) Mechanical Engineering Department and Southern University (SU) Department of Computer Science. This proposal will directly support the technical goals specified in DE-FOA-0000248, Topic Area 3: Turbine Materials, by addressing key technologies needed to enable the development of advanced turbines and turbine-based systems that will operate safely and efficiently using coal-derived synthesis gases. We will develop novel molecular dynamics method to improve the efficiency of simulation on novel TBC materials; we will perform high performance computing (HPC) on complex TBC structures to screen the most promising TBC compositions; we will perform material characterizations and oxidation/corrosion tests; and we will demonstrate our new Thermal barrier coating (TBC) systems experimentally under Integrated gasification combined cycle (IGCC) environments. The durability of the coating will be examined using the proposed High Temperature/High Pressure Durability Test Rig under real syngas product compositions.

  5. Cuby: An Integrative Framework for Computational Chemistry

    Czech Academy of Sciences Publication Activity Database

    Řezáč, Jan

    2016-01-01

    Roč. 37, č. 13 (2016), s. 1230-1237 ISSN 0192-8651 R&D Projects: GA ČR GP13-01214P Institutional support: RVO:61388963 Keywords : software framework * workflow automation * QM/MM * datasets * Ruby Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.229, year: 2016

  6. Experimental and computational evaluation of area selectively immobilized horseradish peroxidase in a microfluidic device

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Pereira Rosinha Grundtvig, Ines; Thrane, Joachim

    2017-01-01

    experimentally and by computational fluid dynamics (CFD) simulations. Ultimately, such a correlation would lead to faster development through computational pre-screening and optimized experimental design.In this proof-of-concept study, microreactors were prepared in a 2-step curing process of an off......-stoichiometric thiol-ene-epoxy (OSTE+) mixture employing both a thiol-ene (TEC) and a thiol-epoxy curing reaction. Subsequent surface functionalization of the remaining thiol groups on the reactor surface through stenciled photoinitiated TEC enabled the preparation of specific surface patterns in the reactor. Patterns...... as obtained from experimental determination. This good agreement between the obtained experimental and computational results confirmed the high potential of CFD models for predicting and optimizing the biocatalytic performance of such a reactor....

  7. Designing a Scalable Fault Tolerance Model for High Performance Computational Chemistry: A Case Study with Coupled Cluster Perturbative Triples.

    Science.gov (United States)

    van Dam, Hubertus J J; Vishnu, Abhinav; de Jong, Wibe A

    2011-01-11

    In the past couple of decades, the massive computational power provided by the most modern supercomputers has resulted in simulation of higher-order computational chemistry methods, previously considered intractable. As the system sizes continue to increase, the computational chemistry domain continues to escalate this trend using parallel computing with programming models such as Message Passing Interface (MPI) and Partitioned Global Address Space (PGAS) programming models such as Global Arrays. The ever increasing scale of these supercomputers comes at a cost of reduced Mean Time Between Failures (MTBF), currently on the order of days and projected to be on the order of hours for upcoming extreme scale systems. While traditional disk-based check pointing methods are ubiquitous for storing intermediate solutions, they suffer from high overhead of writing and recovering from checkpoints. In practice, checkpointing itself often brings the system down. Clearly, methods beyond checkpointing are imperative to handling the aggravating issue of reducing MTBF. In this paper, we address this challenge by designing and implementing an efficient fault tolerant version of the Coupled Cluster (CC) method with NWChem, using in-memory data redundancy. We present the challenges associated with our design, including an efficient data storage model, maintenance of at least one consistent data copy, and the recovery process. Our performance evaluation without faults shows that the current design exhibits a small overhead. In the presence of a simulated fault, the proposed design incurs negligible overhead in comparison to the state of the art implementation without faults.

  8. Emerging Trends in Heart Valve Engineering: Part IV. Computational Modeling and Experimental Studies.

    Science.gov (United States)

    Kheradvar, Arash; Groves, Elliott M; Falahatpisheh, Ahmad; Mofrad, Mohammad K; Hamed Alavi, S; Tranquillo, Robert; Dasi, Lakshmi P; Simmons, Craig A; Jane Grande-Allen, K; Goergen, Craig J; Baaijens, Frank; Little, Stephen H; Canic, Suncica; Griffith, Boyce

    2015-10-01

    In this final portion of an extensive review of heart valve engineering, we focus on the computational methods and experimental studies related to heart valves. The discussion begins with a thorough review of computational modeling and the governing equations of fluid and structural interaction. We then move onto multiscale and disease specific modeling. Finally, advanced methods related to in vitro testing of the heart valves are reviewed. This section of the review series is intended to illustrate application of computational methods and experimental studies and their interrelation for studying heart valves.

  9. Final Report: Main Group Element Chemistry in Service of Hydrogen Storage and Activation

    Energy Technology Data Exchange (ETDEWEB)

    David A. Dixon; Anthony J. Arduengo, III

    2010-09-30

    Replacing combustion of carbon-based fuels with alternative energy sources that have minimal environmental impact is one of the grand scientific and technological challenges of the early 21st century. Not only is it critical to capture energy from new, renewable sources, it is also necessary to store the captured energy efficiently and effectively for use at the point of service when and where it is needed, which may not be collocated with the collection site. There are many potential storage media but we focus on the storage of energy in chemical bonds. It is more efficient to store energy on a per weight basis in chemical bonds. This is because it is hard to pack electrons into small volumes with low weight without the use of chemical bonds. The focus of the project was the development of new chemistries to enable DOE to meet its technical objectives for hydrogen storage using chemical hydrogen storage systems. We provided computational chemistry support in terms of thermodynamics, kinetics, and properties prediction in support of the experimental efforts of the DOE Center of Excellence for Chemical Hydrogen Storage. The goal of the Center is to store energy in chemical bonds involving hydrogen atoms. Once the hydrogen is stored in a set of X-H/Y-H bonds, the hydrogen has to be easily released and the depleted fuel regenerated very efficiently. This differs substantially from our current use of fossil fuel energy sources where the reactant is converted to energy plus CO2 (coal) or CO2 and H2O (gasoline, natural gas), which are released into the atmosphere. In future energy storage scenarios, the spent fuel will be captured and the energy storage medium regenerated. This places substantial additional constraints on the chemistry. The goal of the computational chemistry work was to reduce the time to design new materials and develop materials that meet the 2010 and 2015 DOE objectives in terms of weight percent, volume, release time, and regeneration ability. This

  10. Main Group Element Chemistry in Service of Hydrogen Storage and Activation. Final report

    International Nuclear Information System (INIS)

    Dixon, David A.; Arduengo, Anthony J. III

    2010-01-01

    Replacing combustion of carbon-based fuels with alternative energy sources that have minimal environmental impact is one of the grand scientific and technological challenges of the early 21st century. Not only is it critical to capture energy from new, renewable sources, it is also necessary to store the captured energy efficiently and effectively for use at the point of service when and where it is needed, which may not be collocated with the collection site. There are many potential storage media but we focus on the storage of energy in chemical bonds. It is more efficient to store energy on a per weight basis in chemical bonds. This is because it is hard to pack electrons into small volumes with low weight without the use of chemical bonds. The focus of the project was the development of new chemistries to enable DOE to meet its technical objectives for hydrogen storage using chemical hydrogen storage systems. We provided computational chemistry support in terms of thermodynamics, kinetics, and properties prediction in support of the experimental efforts of the DOE Center of Excellence for Chemical Hydrogen Storage. The goal of the Center is to store energy in chemical bonds involving hydrogen atoms. Once the hydrogen is stored in a set of X-H/Y-H bonds, the hydrogen has to be easily released and the depleted fuel regenerated very efficiently. This differs substantially from our current use of fossil fuel energy sources where the reactant is converted to energy plus CO 2 (coal) or CO 2 and H 2 O (gasoline, natural gas), which are released into the atmosphere. In future energy storage scenarios, the spent fuel will be captured and the energy storage medium regenerated. This places substantial additional constraints on the chemistry. The goal of the computational chemistry work was to reduce the time to design new materials and develop materials that meet the 2010 and 2015 DOE objectives in terms of weight percent, volume, release time, and regeneration ability

  11. An Experimental Study into the use of computers for teaching of ...

    African Journals Online (AJOL)

    This study was an experimental study which sought to establish how English language teachers used computers for teaching composition writing at Prince Edward High School in Harare. The findings of the study show that computers were rarely used in the teaching of composition despite the observation that the school ...

  12. Future in actinoids coordination chemistry

    International Nuclear Information System (INIS)

    Kitazawa, Takafumi

    2006-01-01

    Actinoids coordination chemistry is concerned with spent nuclear fuel reprocessing, specifically with solid-state chemistry of nuclear fuels, separation process with radioactive substances, and geological disposal of high-level radioactive substances. In the 21st century, accumulation of minor actinides, Np, Am, Cm, and others will be realized according with the present program of nuclear energy development. The present article briefly introduces general properties of actinide elements, followed by their coordination chemistry compared with rare earths coordination chemistry. Special facility needed to treat actinoids as well as their chemistry is briefly explained, together with the specific experimental apparatus such as X-ray Absorption Fine Structure (XAFS) and time-resolved laser-induced fluorescence spectrometry (TRLFS) with synchrotron radiation facilities. The effect of coordination with actinoids in the environment chemistry is important in underground disposal of high-level radioactive wastes. For theoretical analysis of the results with actinoids chemistry, relativistic calculation is needed. (S. Ohno)

  13. Computed tomography and plain radiography in experimental fracture healing

    International Nuclear Information System (INIS)

    Braunstein, E.M.; Goldstein, S.A.; Ku, J.; Smith, P.; Matthews, L.S.

    1986-01-01

    We evaluated the relative contribution of plain radiographs and computed tomography to the assessment of fracture healing under experimental circumstances. In 15 sheep, we performed midshaft femoral osteotomies and internal fixation of the resultant segmental fractures. Radiographs were obtained preoperatively and immediately postoperatively. Animals were sacrificed at 3 weeks, 6 weeks, 12 weeks, 24 weeks, and 36 weeks after surgery, and the femoral specimens radiographed. After removal of the internal fixation devices, computed tomographic scans of the specimens were performed. Computed tomography may be of value in the evaluation of fractures of long bones in those cases in which clinical examination and plain radiographs fail to give adequate information as to the status of healing. (orig./SHA)

  14. The Effects of Computer-Assisted Instruction of Simple Circuits on Experimental Process Skills

    Directory of Open Access Journals (Sweden)

    Şeyma ULUKÖK

    2013-01-01

    Full Text Available The experimental and control groups were composed of 30 sophomores majoring in Classroom Teaching for this study investigating the effects of computer-assisted instruction of simple circuits on the development of experimental process skills. The instruction includes experiments and studies about simple circuits and its elements (serial, parallel, and mixed conncetions of resistors covered in Science and Technology Laboratory II course curriculum. In this study where quantitative and qualitative methods were used together, the control list developed by the researchers was used to collect data. Results showed that experimental process skills of sophomores in experimental group were more developed than that of those in control group. Thus, it can be said that computer-assisted instruction has a positive impact on the development of experimental process skills of students.

  15. Heterogeneous catalytic materials solid state chemistry, surface chemistry and catalytic behaviour

    CERN Document Server

    Busca, Guido

    2014-01-01

    Heterogeneous Catalytic Materials discusses experimental methods and the latest developments in three areas of research: heterogeneous catalysis; surface chemistry; and the chemistry of catalysts. Catalytic materials are those solids that allow the chemical reaction to occur efficiently and cost-effectively. This book provides you with all necessary information to synthesize, characterize, and relate the properties of a catalyst to its behavior, enabling you to select the appropriate catalyst for the process and reactor system. Oxides (used both as catalysts and as supports for cata

  16. Computer simulations and the changing face of scientific experimentation

    CERN Document Server

    Duran, Juan M

    2013-01-01

    Computer simulations have become a central tool for scientific practice. Their use has replaced, in many cases, standard experimental procedures. This goes without mentioning cases where the target system is empirical but there are no techniques for direct manipulation of the system, such as astronomical observation. To these cases, computer simulations have proved to be of central importance. The question about their use and implementation, therefore, is not only a technical one but represents a challenge for the humanities as well. In this volume, scientists, historians, and philosophers joi

  17. Experimental and Computational Study of Ductile Fracture in Small Punch Tests

    Directory of Open Access Journals (Sweden)

    Betül Gülçimen Çakan

    2017-10-01

    Full Text Available A unified experimental-computational study on ductile fracture initiation and propagation during small punch testing is presented. Tests are carried out at room temperature with unnotched disks of different thicknesses where large-scale yielding prevails. In thinner specimens, the fracture occurs with severe necking under membrane tension, whereas for thicker ones a through thickness shearing mode prevails changing the crack orientation relative to the loading direction. Computational studies involve finite element simulations using a shear modified Gurson-Tvergaard-Needleman porous plasticity model with an integral-type nonlocal formulation. The predicted punch load-displacement curves and deformed profiles are in good agreement with the experimental results.

  18. Experimental and Computational Study of Ductile Fracture in Small Punch Tests.

    Science.gov (United States)

    Gülçimen Çakan, Betül; Soyarslan, Celal; Bargmann, Swantje; Hähner, Peter

    2017-10-17

    A unified experimental-computational study on ductile fracture initiation and propagation during small punch testing is presented. Tests are carried out at room temperature with unnotched disks of different thicknesses where large-scale yielding prevails. In thinner specimens, the fracture occurs with severe necking under membrane tension, whereas for thicker ones a through thickness shearing mode prevails changing the crack orientation relative to the loading direction. Computational studies involve finite element simulations using a shear modified Gurson-Tvergaard-Needleman porous plasticity model with an integral-type nonlocal formulation. The predicted punch load-displacement curves and deformed profiles are in good agreement with the experimental results.

  19. A combined experimental and computational investigation of excess molar enthalpies of (nitrobenzene + alkanol) mixtures

    International Nuclear Information System (INIS)

    Neyband, Razieh Sadat; Zarei, Hosseinali

    2015-01-01

    Highlights: • Excess molar enthalpies for the binary mixtures of nitrobenzene + alkanols mixtures were measured. • The infinite dilution excess partial molar enthalpies were calculated using the ab initio methods. • The PCM calculations were performed. • The computed excess partial molar enthalpies at infinite dilution were compared to experimental results. - Abstract: Excess molar enthalpies (H m E ) for the binary mixtures of {(nitrobenzene + ethanol), 1-propanol, 2-propanol, 1-butanol and 2-butanol} have been measured over the entire composition range at ambient pressure (81.5 kPa) and temperature 298 K using a Parr 1455 solution calorimeter. From the experimental results, the excess partial molar enthalpies (H i E ) and excess partial molar enthalpies at infinite dilution (H i E,∞ ) were calculated. The excess molar enthalpies (H m E ) are positive for all {nitrobenzene (1) + alkanol (2)} mixtures over the entire composition range. A state-of-the-art computational strategy for the evaluation of excess partial molar enthalpies at infinite dilution was followed at the M05-2X/6-311++G ∗∗ level of theory with the PCM model. The experimental excess partial molar enthalpies at infinite dilution have been compared to the computational data of the ab initio in liquid phase. Integrated experimental and computational results help to clarify the nature of the intermolecular interactions in {nitrobenzene (1) + alkanol (2)} mixtures. The experimental and computational work which was done in this study complements and extends the general research on the computation of excess partial molar enthalpy at infinite dilution of binary mixtures

  20. Numerical Verification Of Equilibrium Chemistry

    International Nuclear Information System (INIS)

    Piro, Markus; Lewis, Brent; Thompson, William T.; Simunovic, Srdjan; Besmann, Theodore M.

    2010-01-01

    A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.

  1. 1st International Conference on Computational and Experimental Biomedical Sciences

    CERN Document Server

    Jorge, RM

    2015-01-01

    This book contains the full papers presented at ICCEBS 2013 – the 1st International Conference on Computational and Experimental Biomedical Sciences, which was organized in Azores, in October 2013. The included papers present and discuss new trends in those fields, using several methods and techniques, including active shape models, constitutive models, isogeometric elements, genetic algorithms, level sets, material models, neural networks, optimization, and the finite element method, in order to address more efficiently different and timely applications involving biofluids, computer simulation, computational biomechanics, image based diagnosis, image processing and analysis, image segmentation, image registration, scaffolds, simulation, and surgical planning. The main audience for this book consists of researchers, Ph.D students, and graduate students with multidisciplinary interests related to the areas of artificial intelligence, bioengineering, biology, biomechanics, computational fluid dynamics, comput...

  2. Experimental investigation and numerical modelling of positive corona discharge: ozone generation

    Energy Technology Data Exchange (ETDEWEB)

    Yanallah, K; Castellanos, A [Departamento de Electronica y Electromagnetismo, Universidad de Sevilla (Spain); Pontiga, F; Fernandez-Rueda, A [Departamento de FIsica Aplicada II, Universidad de Sevilla (Spain)

    2009-03-21

    The spatial distribution of the species generated in a wire-cylinder positive corona discharge in pure oxygen has been computed using a plasma chemistry model that includes the most significant reactions between electrons, ions, atoms and molecules. The plasma chemistry model is included in the continuity equations of each species, which are coupled with Poisson's equation for the electric field and the energy conservation equation for the gas temperature. The current-voltage characteristic measured in the experiments has been used as an input data to the numerical simulation. The numerical model is able to reproduce the basic structure of the positive corona discharge and highlights the importance of Joule heating on ozone generation. The average ozone density has been computed as a function of current intensity and compared with the experimental measurements of ozone concentration determined by UV absorption spectroscopy.

  3. Experimental investigation and numerical modelling of positive corona discharge: ozone generation

    International Nuclear Information System (INIS)

    Yanallah, K; Castellanos, A; Pontiga, F; Fernandez-Rueda, A

    2009-01-01

    The spatial distribution of the species generated in a wire-cylinder positive corona discharge in pure oxygen has been computed using a plasma chemistry model that includes the most significant reactions between electrons, ions, atoms and molecules. The plasma chemistry model is included in the continuity equations of each species, which are coupled with Poisson's equation for the electric field and the energy conservation equation for the gas temperature. The current-voltage characteristic measured in the experiments has been used as an input data to the numerical simulation. The numerical model is able to reproduce the basic structure of the positive corona discharge and highlights the importance of Joule heating on ozone generation. The average ozone density has been computed as a function of current intensity and compared with the experimental measurements of ozone concentration determined by UV absorption spectroscopy.

  4. Experimental investigation and numerical modelling of positive corona discharge: ozone generation

    Science.gov (United States)

    Yanallah, K; Pontiga, F; Fernández-Rueda, A; Castellanos, A

    2009-03-01

    The spatial distribution of the species generated in a wire-cylinder positive corona discharge in pure oxygen has been computed using a plasma chemistry model that includes the most significant reactions between electrons, ions, atoms and molecules. The plasma chemistry model is included in the continuity equations of each species, which are coupled with Poisson's equation for the electric field and the energy conservation equation for the gas temperature. The current-voltage characteristic measured in the experiments has been used as an input data to the numerical simulation. The numerical model is able to reproduce the basic structure of the positive corona discharge and highlights the importance of Joule heating on ozone generation. The average ozone density has been computed as a function of current intensity and compared with the experimental measurements of ozone concentration determined by UV absorption spectroscopy.

  5. A green chemistry lab course

    International Nuclear Information System (INIS)

    Rank, J.; Lenoir, D.; Bahadir, M.; Koning, B.

    2006-01-01

    The traditional course content of chemistry classes must change to achieve better awareness of the important issues of sustainability in chemistry within the next generation of professional chemists. To provide the necessary material for the organic chemistry teaching lab course, which is part of almost all study programs in chemistry, material was developed and collected (http://www.oc-praktikum.de/en) that allows students and teachers to assess reactions beyond the experimental set up, reaction mechanism and chemical yield. Additional parameters like atom economy of chemical transformations, energy efficiency, and questions of waste, renewable feed stocks, toxicity and ecotoxicity, as well as the safety measures for the chemicals used are discussed. (author)

  6. Comptox Chemistry Dashboard: Web-Based Data Integration Hub for Environmental Chemistry and Toxicology Data (ACS Fall meeting 4 of 12)

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program integrate advances in biology, chemistry, exposure and computer science to help prioritize chemicals for further research based on potential human health risks. This work involves computational and da...

  7. Computational Flame Diagnostics for Direct Numerical Simulations with Detailed Chemistry of Transportation Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tianfeng [Univ. of Connecticut, Storrs, CT (United States)

    2017-02-16

    The goal of the proposed research is to create computational flame diagnostics (CFLD) that are rigorous numerical algorithms for systematic detection of critical flame features, such as ignition, extinction, and premixed and non-premixed flamelets, and to understand the underlying physicochemical processes controlling limit flame phenomena, flame stabilization, turbulence-chemistry interactions and pollutant emissions etc. The goal has been accomplished through an integrated effort on mechanism reduction, direct numerical simulations (DNS) of flames at engine conditions and a variety of turbulent flames with transport fuels, computational diagnostics, turbulence modeling, and DNS data mining and data reduction. The computational diagnostics are primarily based on the chemical explosive mode analysis (CEMA) and a recently developed bifurcation analysis using datasets from first-principle simulations of 0-D reactors, 1-D laminar flames, and 2-D and 3-D DNS (collaboration with J.H. Chen and S. Som at Argonne, and C.S. Yoo at UNIST). Non-stiff reduced mechanisms for transportation fuels amenable for 3-D DNS are developed through graph-based methods and timescale analysis. The flame structures, stabilization mechanisms, local ignition and extinction etc., and the rate controlling chemical processes are unambiguously identified through CFLD. CEMA is further employed to segment complex turbulent flames based on the critical flame features, such as premixed reaction fronts, and to enable zone-adaptive turbulent combustion modeling.

  8. Identifying controlling variables for math computation fluency through experimental analysis: the interaction of stimulus control and reinforcing consequences.

    Science.gov (United States)

    Hofstadter-Duke, Kristi L; Daly, Edward J

    2015-03-01

    This study investigated a method for conducting experimental analyses of academic responding. In the experimental analyses, academic responding (math computation), rather than problem behavior, was reinforced across conditions. Two separate experimental analyses (one with fluent math computation problems and one with non-fluent math computation problems) were conducted with three elementary school children using identical contingencies while math computation rate was measured. Results indicate that the experimental analysis with non-fluent problems produced undifferentiated responding across participants; however, differentiated responding was achieved for all participants in the experimental analysis with fluent problems. A subsequent comparison of the single-most effective condition from the experimental analyses replicated the findings with novel computation problems. Results are discussed in terms of the critical role of stimulus control in identifying controlling consequences for academic deficits, and recommendations for future research refining and extending experimental analysis to academic responding are made. © The Author(s) 2014.

  9. Experimental and computational approaches to evaluate the environmental mitigation effect in narrow spaces by noble metal chemical addition (NMCA)

    International Nuclear Information System (INIS)

    Shimizu, Ryosuke; Ota, Nobuyuki; Nagase, Makoto; Aizawa, Motohiro; Ishida, Kazushige; Wada, Yoichi

    2014-01-01

    The environmental mitigation effect of NMCA in a narrow space was evaluated by experimental and computational approaches. In the experiment at 8 MPa and 553K, T-tube whose branched line had a narrow space was prepared, and the Zr electrodes were set in the branched line at certain intervals, which were 1, 3, 5, 7, 9, 11, 15 and 29 cm from the opening section of the branched line. Electrochemical corrosion potential (ECP) at the tip of the branched narrow space varied in response to the water chemistry in the main line which was at right angle with the branched line. Computational fluid dynamics (CFD) analysis reproduced the experimental results. It was also confirmed by CFD analysis that the ingress of water from the main line into the narrow space was accelerated by cavity flow and thermal convection. By CFD analysis in a thermal sleeve of actual plant condition, which had a narrow space, the concentration of dissolved oxygen at a tip of the thermal sleeve reached at 250 ppb within 300 sec, which was the same concentration of the main line. Noble metal deposition on the surface of the thermal sleeve was evaluated by mass transfer model. Noble metal deposition was the largest near the opening section of the branched line, and gradually decreased toward the tip section. In light of the consumption of dissolved oxygen in the branched line, noble metal deposition in the thermal sleeve was sufficient to reduce the ECP. It was expected that NMCA could mitigate the corrosion environment in the thermal sleeve. (author)

  10. A hybrid computational-experimental approach for automated crystal structure solution

    Science.gov (United States)

    Meredig, Bryce; Wolverton, C.

    2013-02-01

    Crystal structure solution from diffraction experiments is one of the most fundamental tasks in materials science, chemistry, physics and geology. Unfortunately, numerous factors render this process labour intensive and error prone. Experimental conditions, such as high pressure or structural metastability, often complicate characterization. Furthermore, many materials of great modern interest, such as batteries and hydrogen storage media, contain light elements such as Li and H that only weakly scatter X-rays. Finally, structural refinements generally require significant human input and intuition, as they rely on good initial guesses for the target structure. To address these many challenges, we demonstrate a new hybrid approach, first-principles-assisted structure solution (FPASS), which combines experimental diffraction data, statistical symmetry information and first-principles-based algorithmic optimization to automatically solve crystal structures. We demonstrate the broad utility of FPASS to clarify four important crystal structure debates: the hydrogen storage candidates MgNH and NH3BH3; Li2O2, relevant to Li-air batteries; and high-pressure silane, SiH4.

  11. Computation: A New Open Access Journal of Computational Chemistry, Computational Biology and Computational Engineering

    OpenAIRE

    Karlheinz Schwarz; Rainer Breitling; Christian Allen

    2013-01-01

    Computation (ISSN 2079-3197; http://www.mdpi.com/journal/computation) is an international scientific open access journal focusing on fundamental work in the field of computational science and engineering. Computational science has become essential in many research areas by contributing to solving complex problems in fundamental science all the way to engineering. The very broad range of application domains suggests structuring this journal into three sections, which are briefly characterized ...

  12. Numerical simulation of the insert chemistry of the hollow cathode from the deep space 1 ion engine 30,000 Hrs life test

    OpenAIRE

    Coletti, Michele; Grubisic, Angelo; Gabriel, Stephen

    2007-01-01

    A model for the insert chemistry developed by the authors and based on the knowledge of the BaO – CaO – Al2O3 ternary system the ELT discharge cathode insert from the Deep Space 1 life test has been simulated. The computed data show a good agreement with the experimental one; the agreement increase with the imposition of boundary conditions closer to the experimental evidence. Tungsten deposition effect have been introduced into the model using experimental data and further improving the agre...

  13. Simulating chemistry using quantum computers.

    Science.gov (United States)

    Kassal, Ivan; Whitfield, James D; Perdomo-Ortiz, Alejandro; Yung, Man-Hong; Aspuru-Guzik, Alán

    2011-01-01

    The difficulty of simulating quantum systems, well known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.

  14. WHAT MAKES CHEMISTRY DIFFICULT?

    African Journals Online (AJOL)

    IICBA01

    School of Natural and Computational Science Dire Dawa University, Ethiopia,. 2 ... lack of teaching aids and the difficulty of the language of chemistry. ... lab every other week consisting of concept pretests on the web, hand-written homework, ...

  15. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  16. Effectiveness of Student Learning during Experimental Work in Primary School.

    Science.gov (United States)

    Logar, Ana; Peklaj, Cirila; Ferk Savec, Vesna

    2017-09-01

    The aim of the research was to optimize the effectiveness of student learning based on experimental work in chemistry classes in Slovenian primary schools. To obtain evidence about how experimental work is implemented during regular chemistry classes, experimental work was videotaped during 19 units of chemistry lessons at 12 Slovenian primary schools from the pool of randomly selected schools. Altogether 332 eight-grade students were involved in the investigation, with an average age of 14.2 years. Students were videotaped during chemistry lessons, and their worksheets were collected afterward. The 12 chemistry teachers, who conducted lessons in these schools, were interviewed before the lessons; their teaching plans were also collected. The collected data was analyzed using qualitative methods. The results indicate that many teachers in Slovenian primary schools are not fully aware of the potential of experimental work integrated into chemistry lessons for the development of students' experimental competence. Further research of the value of different kinds of training to support teachers for the use of experimental work in chemistry teaching is needed.

  17. On air-chemistry reduction for hypersonic external flow applications

    International Nuclear Information System (INIS)

    Ibrahim, Ashraf; Suman, Sawan; Girimaji, Sharath S.

    2015-01-01

    Highlights: • The existence of the slow manifold for the air-mixture system is shown. • The QSSA estimate of the slow manifold is fairly accurate. • For mid-temperature range the reduction mechanisms could be useful. - Abstract: In external hypersonic flows, viscous and compressibility effects generate very high temperatures leading to significant chemical reactions among air constituents. Therefore, hypersonic flow computations require coupled calculations of flow and chemistry. Accurate and efficient computations of air-chemistry kinetics are of much importance for many practical applications but calculations accounting for detailed chemical kinetics can be prohibitively expensive. In this paper, we investigate the possibility of applying chemical kinetics reduction schemes for hypersonic air-chemistry. We consider two chemical kinetics sets appropriate for three different temperature ranges: 2500 K to 4500 K; 4500 K to 9000 K; and above 9000 K. By demonstrating the existence of the so-called the slow manifold in each of the chemistry sets, we show that judicious chemical kinetics reduction leading to significant computational savings is possible without much loss in accuracy

  18. Chemistry Division: Annual progress report for period ending March 31, 1987

    International Nuclear Information System (INIS)

    1987-08-01

    This report is divided into the following sections: coal chemistry; aqueous chemistry at high temperatures and pressures; geochemistry of crustal processes to high temperatures and pressures; chemistry of advanced inorganic materials; structure and dynamics of advanced polymeric materials; chemistry of transuranium elements and compounds; separations chemistry; reactions and catalysis in molten salts; surface science related to heterogeneous catalysis; electron spectroscopy; chemistry related to nuclear waste disposal; computational modeling of security document printing; and special topics

  19. High fidelity chemistry and radiation modeling for oxy -- combustion scenarios

    Science.gov (United States)

    Abdul Sater, Hassan A.

    To account for the thermal and chemical effects associated with the high CO2 concentrations in an oxy-combustion atmosphere, several refined gas-phase chemistry and radiative property models have been formulated for laminar to highly turbulent systems. This thesis examines the accuracies of several chemistry and radiative property models employed in computational fluid dynamic (CFD) simulations of laminar to transitional oxy-methane diffusion flames by comparing their predictions against experimental data. Literature review about chemistry and radiation modeling in oxy-combustion atmospheres considered turbulent systems where the predictions are impacted by the interplay and accuracies of the turbulence, radiation and chemistry models. Thus, by considering a laminar system we minimize the impact of turbulence and the uncertainties associated with turbulence models. In the first section of this thesis, an assessment and validation of gray and non-gray formulations of a recently proposed weighted-sum-of-gray gas model in oxy-combustion scenarios was undertaken. Predictions of gas, wall temperatures and flame lengths were in good agreement with experimental measurements. The temperature and flame length predictions were not sensitive to the radiative property model employed. However, there were significant variations between the gray and non-gray model radiant fraction predictions with the variations in general increasing with decrease in Reynolds numbers possibly attributed to shorter flames and steeper temperature gradients. The results of this section confirm that non-gray model predictions of radiative heat fluxes are more accurate than gray model predictions especially at steeper temperature gradients. In the second section, the accuracies of three gas-phase chemistry models were assessed by comparing their predictions against experimental measurements of temperature, species concentrations and flame lengths. The chemistry was modeled employing the Eddy

  20. Surface Traps in Colloidal Quantum Dots: A Combined Experimental and Theoretical Perspective.

    Science.gov (United States)

    Giansante, Carlo; Infante, Ivan

    2017-10-19

    Surface traps are ubiquitous to nanoscopic semiconductor materials. Understanding their atomistic origin and manipulating them chemically have capital importance to design defect-free colloidal quantum dots and make a leap forward in the development of efficient optoelectronic devices. Recent advances in computing power established computational chemistry as a powerful tool to describe accurately complex chemical species and nowadays it became conceivable to model colloidal quantum dots with realistic sizes and shapes. In this Perspective, we combine the knowledge gathered in recent experimental findings with the computation of quantum dot electronic structures. We analyze three different systems: namely, CdSe, PbS, and CsPbI 3 as benchmark semiconductor nanocrystals showing how different types of trap states can form at their surface. In addition, we suggest experimental healing of such traps according to their chemical origin and nanocrystal composition.

  1. Contribution of computer science to the evaluation of experimental data

    International Nuclear Information System (INIS)

    Steuerwald, J.

    1978-11-01

    The GALE data acquisition system and EDDAR data processing system, used at Max-Planck-Institut fuer Plasmaphysik, serve to illustrate some of the various ways in which computer science plays a major role in developing the evaluation of experimental data. (orig.) [de

  2. Computational design and experimental validation of new thermal barrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin [Louisiana State Univ., Baton Rouge, LA (United States)

    2015-03-31

    The focus of this project is on the development of a reliable and efficient ab initio based computational high temperature material design method which can be used to assist the Thermal Barrier Coating (TBC) bond-coat and top-coat design. Experimental evaluations on the new TBCs are conducted to confirm the new TBCs’ properties. Southern University is the subcontractor on this project with a focus on the computational simulation method development. We have performed ab initio density functional theory (DFT) method and molecular dynamics simulation on screening the top coats and bond coats for gas turbine thermal barrier coating design and validation applications. For experimental validations, our focus is on the hot corrosion performance of different TBC systems. For example, for one of the top coatings studied, we examined the thermal stability of TaZr2.75O8 and confirmed it’s hot corrosion performance.

  3. Implementing a Student-Designed Green Chemistry Laboratory Project in Organic Chemistry

    Science.gov (United States)

    Graham, Kate J.; Jones, T. Nicholas; Schaller, Chris P.; McIntee, Edward J.

    2014-01-01

    A multiweek organic chemistry laboratory project is described that emphasizes sustainable practices in experimental design. An emphasis on student-driven development of the project is meant to mirror the independent nature of research. Students propose environmentally friendly modifications of several reactions. With instructor feedback, students…

  4. Quantum Chemistry; A concise introduction for students of physics, chemistry, biochemistry and materials science

    Science.gov (United States)

    Thakkar, Ajit J.

    2017-09-01

    This book provides non-specialists with a basic understanding of the underlying concepts of quantum chemistry. It is both a text for second- or third-year undergraduates and a reference for researchers who need a quick introduction or refresher. All chemists and many biochemists, materials scientists, engineers, and physicists routinely use spectroscopic measurements and electronic structure computations in their work. The emphasis of Quantum Chemistry on explaining ideas rather than enumerating facts or presenting procedural details makes this an excellent foundation text/reference.

  5. Computer-Based Learning in Chemistry Classes

    Science.gov (United States)

    Pietzner, Verena

    2014-01-01

    Currently not many people would doubt that computers play an essential role in both public and private life in many countries. However, somewhat surprisingly, evidence of computer use is difficult to find in German state schools although other countries have managed to implement computer-based teaching and learning in their schools. This paper…

  6. Electronic properties of Fe charge transfer complexes – A combined experimental and theoretical approach

    International Nuclear Information System (INIS)

    Ferreira, Hendrik; Eschwege, Karel G. von; Conradie, Jeanet

    2016-01-01

    Highlights: • Experimental and computational study of Fe II -phen, -bpy & -tpy compleesx. • Close correlations between experimental redox and spectral, and computational data. • Computational methods fast-track DSSC research. - Abstract: Dye-sensitized solar cell technology holds huge potential in renewable electricity generation of the future. Due to demand urgency, ways need to be explored to reduce research time and cost. Against this background, quantum computational chemistry is illustrated to be a reliable tool at the onset of studies in this field, simulating charge transfer, spectral (solar energy absorbed) and electrochemical (ease by which electrons may be liberated) tuning of related photo-responsive dyes. Comparative experimental and theoretical DFT studies were done under similar conditions, involving an extended series of electrochemically altered phenanthrolines, bipyridyl and terpyridyl complexes of Fe II . Fe II/III oxidation waves vary from 0.363 V for tris(3,6-dimethoxybipyridyl)Fe II to 0.894 V (versus Fc/Fc + ) for the 5-nitrophenanthroline complex. Theoretical DFT computed ionization potentials in the bipyridyl sub-series achieved an almost 100% linear correlation with experimental electrochemical oxidation potentials, while the phenanthroline sub-series gave R 2 = 0.95. Apart from the terpyridyl complex which accorded an almost perfect match, in general, TDDFT oscillators were computed at slightly lower energies than what was observed experimentally, while molecular HOMO and LUMO renderings reveal desired complexes with directional charge transfer propensities.

  7. Hot atom chemistry of carbon

    International Nuclear Information System (INIS)

    Wolf, A.P.

    1975-01-01

    The chemistry of energetic carbon atoms is discussed. The experimental approach to studies that have been carried out is described and the mechanistic framework of hot carbon atom reactions is considered in some detail. Finally, the direction that future work might take is examined, including the relationship of experimental to theoretical work. (author)

  8. Computational Fluid Dynamics Modeling of the Human Pulmonary Arteries with Experimental Validation.

    Science.gov (United States)

    Bordones, Alifer D; Leroux, Matthew; Kheyfets, Vitaly O; Wu, Yu-An; Chen, Chia-Yuan; Finol, Ender A

    2018-05-21

    Pulmonary hypertension (PH) is a chronic progressive disease characterized by elevated pulmonary arterial pressure, caused by an increase in pulmonary arterial impedance. Computational fluid dynamics (CFD) can be used to identify metrics representative of the stage of PH disease. However, experimental validation of CFD models is often not pursued due to the geometric complexity of the model or uncertainties in the reproduction of the required flow conditions. The goal of this work is to validate experimentally a CFD model of a pulmonary artery phantom using a particle image velocimetry (PIV) technique. Rapid prototyping was used for the construction of the patient-specific pulmonary geometry, derived from chest computed tomography angiography images. CFD simulations were performed with the pulmonary model with a Reynolds number matching those of the experiments. Flow rates, the velocity field, and shear stress distributions obtained with the CFD simulations were compared to their counterparts from the PIV flow visualization experiments. Computationally predicted flow rates were within 1% of the experimental measurements for three of the four branches of the CFD model. The mean velocities in four transversal planes of study were within 5.9 to 13.1% of the experimental mean velocities. Shear stresses were qualitatively similar between the two methods with some discrepancies in the regions of high velocity gradients. The fluid flow differences between the CFD model and the PIV phantom are attributed to experimental inaccuracies and the relative compliance of the phantom. This comparative analysis yielded valuable information on the accuracy of CFD predicted hemodynamics in pulmonary circulation models.

  9. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  10. Chemistry Division: Annual progress report for period ending March 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-08-01

    This report is divided into the following sections: coal chemistry; aqueous chemistry at high temperatures and pressures; geochemistry of crustal processes to high temperatures and pressures; chemistry of advanced inorganic materials; structure and dynamics of advanced polymeric materials; chemistry of transuranium elements and compounds; separations chemistry; reactions and catalysis in molten salts; surface science related to heterogeneous catalysis; electron spectroscopy; chemistry related to nuclear waste disposal; computational modeling of security document printing; and special topics. (DLC)

  11. Computer analysis of potentiometric data of complexes formation in the solution

    Science.gov (United States)

    Jastrzab, Renata; Kaczmarek, Małgorzata T.; Tylkowski, Bartosz; Odani, Akira

    2018-02-01

    The determination of equilibrium constants is an important process for many branches of chemistry. In this review we provide the readers with a discussion on computer methods which have been applied for elaboration of potentiometric experimental data generated during complexes formation in solution. The review describes both: general basis of modeling tools and examples of the use of calculated stability constants.

  12. Abstracts of the 16. Latin-American Congress of Chemistry

    International Nuclear Information System (INIS)

    1984-01-01

    Abstracts of experimental works on analytical chemistry, physical-chemistry, medical chemistry and technology of chemical processes are presented. Those papers dealing with the application of nuclear techniques for the analysis of various substances and also those concerned with the study of materials and/or elements of nuclear interest, are indexed. (C.L.B.) [pt

  13. Computer Series, 3: Computer Graphics for Chemical Education.

    Science.gov (United States)

    Soltzberg, Leonard J.

    1979-01-01

    Surveys the current scene in computer graphics from the point of view of a chemistry educator. Discusses the scope of current applications of computer graphics in chemical education, and provides information about hardware and software systems to promote communication with vendors of computer graphics equipment. (HM)

  14. Recent developments in computer vision-based analytical chemistry: A tutorial review.

    Science.gov (United States)

    Capitán-Vallvey, Luis Fermín; López-Ruiz, Nuria; Martínez-Olmos, Antonio; Erenas, Miguel M; Palma, Alberto J

    2015-10-29

    Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Evaluation of an Integrated Curriculum in Physics, Mathematics, Engineering, and Chemistry

    Science.gov (United States)

    Beichner, Robert

    1997-04-01

    An experimental, student centered, introductory curriculum called IMPEC (for Integrated Mathematics, Physics, Engineering, and Chemistry curriculum) is in its third year of pilot-testing at NCSU. The curriculum is taught by a multidisciplinary team of professors using a combination of traditional lecturing and alternative instructional methods including cooperative learning, activity-based class sessions, and extensive use of computer modeling, simulations, and the world wide web. This talk will discuss the research basis for our design and implementation of the curriculum, the qualitative and quantitative methods we have been using to assess its effectiveness, and the educational outcomes we have noted so far.

  16. Computer-Aided Construction of Chemical Kinetic Models

    Energy Technology Data Exchange (ETDEWEB)

    Green, William H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-12-31

    The combustion chemistry of even simple fuels can be extremely complex, involving hundreds or thousands of kinetically significant species. The most reasonable way to deal with this complexity is to use a computer not only to numerically solve the kinetic model, but also to construct the kinetic model in the first place. Because these large models contain so many numerical parameters (e.g. rate coefficients, thermochemistry) one never has sufficient data to uniquely determine them all experimentally. Instead one must work in “predictive” mode, using theoretical rather than experimental values for many of the numbers in the model, and as appropriate refining the most sensitive numbers through experiments. Predictive chemical kinetics is exactly what is needed for computer-aided design of combustion systems based on proposed alternative fuels, particularly for early assessment of the value and viability of proposed new fuels before those fuels are commercially available. This project was aimed at making accurate predictive chemical kinetics practical; this is a challenging goal which requires a range of science advances. The project spanned a wide range from quantum chemical calculations on individual molecules and elementary-step reactions, through the development of improved rate/thermo calculation procedures, the creation of algorithms and software for constructing and solving kinetic simulations, the invention of methods for model-reduction while maintaining error control, and finally comparisons with experiment. Many of the parameters in the models were derived from quantum chemistry calculations, and the models were compared with experimental data measured in our lab or in collaboration with others.

  17. Combined computational and experimental study of Ar beam induced defect formation in graphite

    International Nuclear Information System (INIS)

    Pregler, Sharon K.; Hayakawa, Tetsuichiro; Yasumatsu, Hisato; Kondow, Tamotsu; Sinnott, Susan B.

    2007-01-01

    Irradiation of graphite, commonly used in nuclear power plants, is known to produce structural damage. Here, experimental and computational methods are used to study defect formation in graphite during Ar irradiation at incident energies of 50 eV. The experimental samples are analyzed with scanning tunneling microscopy to quantify the size distribution of the defects that form. The computational approach is classical molecular dynamic simulations that illustrate the mechanisms by which the defects are produced. The results indicate that defects in graphite grow in concentrated areas and are nucleated by the presence of existing defects

  18. Chemistry and radiation in oxy-fuel combustion

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2011-01-01

    In order to investigate the role of combustion chemistry and radiation heat transfer in oxy-fuel combustion modeling, a computational fluid dynamics (CFD) modeling study has been performed for two different oxy-fuel furnaces. One is a lab-scale 0.8MW oxy-natural gas flame furnace whose detailed in....... Among the key issues in combustion modeling, e.g., mixing, radiation and chemistry, this paper derives useful guidelines on radiation and chemistry implementation for reliable CFD analyses of oxy-fuel combustion, particularly for industrial applications....

  19. Computation: A New Open Access Journal of Computational Chemistry, Computational Biology and Computational Engineering

    Directory of Open Access Journals (Sweden)

    Karlheinz Schwarz

    2013-09-01

    Full Text Available Computation (ISSN 2079-3197; http://www.mdpi.com/journal/computation is an international scientific open access journal focusing on fundamental work in the field of computational science and engineering. Computational science has become essential in many research areas by contributing to solving complex problems in fundamental science all the way to engineering. The very broad range of application domains suggests structuring this journal into three sections, which are briefly characterized below. In each section a further focusing will be provided by occasionally organizing special issues on topics of high interests, collecting papers on fundamental work in the field. More applied papers should be submitted to their corresponding specialist journals. To help us achieve our goal with this journal, we have an excellent editorial board to advise us on the exciting current and future trends in computation from methodology to application. We very much look forward to hearing all about the research going on across the world. [...

  20. Experimental and computational laser tissue welding using a protein patch.

    Science.gov (United States)

    Small, W; Heredia, N J; Maitland, D J; Eder, D C; Celliers, P M; Da Silva, L B; London, R A; Matthews, D L

    1998-01-01

    An in vitro study of laser tissue welding mediated with a dye-enhanced protein patch was conducted. Fresh sections of porcine aorta were used for the experiments. Arteriotomies were treated using an indocyanine green dye-enhanced collagen patch activated by an 805-nm continuous-wave fiber-delivered diode laser. Temperature histories of the surface of the weld site were obtained using a hollow glass optical fiber-based two-color infrared thermometer. The experimental effort was complemented by simulations with the LATIS (LAser-TISsue) computer code, which uses coupled Monte Carlo, thermal transport, and mass transport models. Comparison of simulated and experimental thermal data indicated that evaporative cooling clamped the surface temperature of the weld site below 100 °C. For fluences of approximately 200 J/cm2, peak surface temperatures averaged 74°C and acute burst strengths consistently exceeded 0.14×106 dyn/cm (hoop tension). The combination of experimental and simulation results showed that the inclusion of water transport and evaporative losses in the computer code has a significant impact on the thermal distributions and hydration levels throughout the tissue volume. The solid-matrix protein patch provided a means of controllable energy delivery and yielded consistently strong welds. © 1998 Society of Photo-Optical Instrumentation Engineers.

  1. Mathematical methods for physical and analytical chemistry

    CERN Document Server

    Goodson, David Z

    2011-01-01

    Mathematical Methods for Physical and Analytical Chemistry presents mathematical and statistical methods to students of chemistry at the intermediate, post-calculus level. The content includes a review of general calculus; a review of numerical techniques often omitted from calculus courses, such as cubic splines and Newton's method; a detailed treatment of statistical methods for experimental data analysis; complex numbers; extrapolation; linear algebra; and differential equations. With numerous example problems and helpful anecdotes, this text gives chemistry students the mathematical

  2. Conformational Analysis of Drug Molecules: A Practical Exercise in the Medicinal Chemistry Course

    Science.gov (United States)

    Yuriev, Elizabeth; Chalmers, David; Capuano, Ben

    2009-01-01

    Medicinal chemistry is a specialized, scientific discipline. Computational chemistry and structure-based drug design constitute important themes in the education of medicinal chemists. This problem-based task is associated with structure-based drug design lectures. It requires students to use computational techniques to investigate conformational…

  3. The European Patent Office and its handling of Computer Implemented Inventions

    CERN Multimedia

    CERN. Geneva; Weber, Georg

    2014-01-01

    Georg Weber joined the EPO in 1988 and is director since more than 10 years. He started his career in the office initially as a patent examiner and worked in different technical areas of chemistry and mechanics. Birger Koblitz is patent examiner at the EPO in Munich in the technical field of computer security. Before joining the office in 2009, he earned a PhD in Experimental Particle Physics from the University of Hamburg, and worked at CERN in the IT department supporting the experiments in their Grid Computing activitie...

  4. Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, Margaret [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-02-24

    Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecular structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.

  5. Complex Chemical Reaction Networks from Heuristics-Aided Quantum Chemistry.

    Science.gov (United States)

    Rappoport, Dmitrij; Galvin, Cooper J; Zubarev, Dmitry Yu; Aspuru-Guzik, Alán

    2014-03-11

    While structures and reactivities of many small molecules can be computed efficiently and accurately using quantum chemical methods, heuristic approaches remain essential for modeling complex structures and large-scale chemical systems. Here, we present a heuristics-aided quantum chemical methodology applicable to complex chemical reaction networks such as those arising in cell metabolism and prebiotic chemistry. Chemical heuristics offer an expedient way of traversing high-dimensional reactive potential energy surfaces and are combined here with quantum chemical structure optimizations, which yield the structures and energies of the reaction intermediates and products. Application of heuristics-aided quantum chemical methodology to the formose reaction reproduces the experimentally observed reaction products, major reaction pathways, and autocatalytic cycles.

  6. Primary water chemistry optimization for extended fuel cycle operation. Results of the 'Duo experimentation' after three cycles

    International Nuclear Information System (INIS)

    Viricel, L.; Andrieu, C.; Segura, J.C.; Rocher, A.; Thomazet, J.; Clinard, M.H.; Dacquait, F.

    2002-01-01

    The primary coolant conditioning in French nuclear power plants is essentially based on the boron-lithium coordinated chemistry, with a target pH of 7.2 at 300 C and a maximum lithium concentration of 2.2 mg/kg. In 1996, EDF 1300 MWe units began operating 18-month fuel cycles, increasing boron concentrations at the beginning of the cycles. Since today the maximum lithium concentration in normal operation is 2.2 mg/kg, extended cycle operation results in a decrease in the pH at the beginning of the cycles, which may possibly lead to deposits in RCS, and particularly on the fuel cladding, and increased dose rates. It has to be noted that today, the fuel assemblies maximum burnup is set at 52 GWd/tU. One solution is to adjust the pH by increasing the lithium content at the beginning of the cycles, which is easy to implement and does not require any modification on the units. Hence, EDF is testing a ''modified'' chemistry regime in the > during 4 fuel cycles, with a maximum authorized lithium content of 3.5 mg/kg at the beginning of the cycles in the Cattenom 2 pilot unit. The Golfech 1 reference unit implements a standard boron-lithium coordination pH 300 7.2. The major goal of the experimentation is to assess the impact of elevated lithium concentrations at the beginning of the cycles on fuel cladding oxide behavior, mass transport and dose rates. This paper presents the results of the first three cycles of the Duo experimentation. (author)

  7. Software platform virtualization in chemistry research and university teaching.

    Science.gov (United States)

    Kind, Tobias; Leamy, Tim; Leary, Julie A; Fiehn, Oliver

    2009-11-16

    Modern chemistry laboratories operate with a wide range of software applications under different operating systems, such as Windows, LINUX or Mac OS X. Instead of installing software on different computers it is possible to install those applications on a single computer using Virtual Machine software. Software platform virtualization allows a single guest operating system to execute multiple other operating systems on the same computer. We apply and discuss the use of virtual machines in chemistry research and teaching laboratories. Virtual machines are commonly used for cheminformatics software development and testing. Benchmarking multiple chemistry software packages we have confirmed that the computational speed penalty for using virtual machines is low and around 5% to 10%. Software virtualization in a teaching environment allows faster deployment and easy use of commercial and open source software in hands-on computer teaching labs. Software virtualization in chemistry, mass spectrometry and cheminformatics is needed for software testing and development of software for different operating systems. In order to obtain maximum performance the virtualization software should be multi-core enabled and allow the use of multiprocessor configurations in the virtual machine environment. Server consolidation, by running multiple tasks and operating systems on a single physical machine, can lead to lower maintenance and hardware costs especially in small research labs. The use of virtual machines can prevent software virus infections and security breaches when used as a sandbox system for internet access and software testing. Complex software setups can be created with virtual machines and are easily deployed later to multiple computers for hands-on teaching classes. We discuss the popularity of bioinformatics compared to cheminformatics as well as the missing cheminformatics education at universities worldwide.

  8. The quark gluon plasma: Lattice computations put to experimental test

    Indian Academy of Sciences (India)

    I describe how lattice computations are being used to extract experimentally relevant features of the quark gluon plasma. I deal specifically with relaxation times, photon emissivity, strangeness yields, event-by-event fluctuations of conserved quantities and hydrodynamic flow. Finally I give evidence that the plasma is rather ...

  9. Benchmark studies of computer prediction techniques for equilibrium chemistry and radionuclide transport in groundwater flow

    International Nuclear Information System (INIS)

    Broyd, T.W.

    1988-01-01

    A brief review of two recent benchmark exercises is presented. These were separately concerned with the equilibrium chemistry of groundwater and the geosphere migration of radionuclides, and involved the use of a total of 19 computer codes by 11 organisations in Europe and Canada. A similar methodology was followed for each exercise, in that series of hypothetical test cases were used to explore the limits of each code's application, and so provide an overview of current modelling potential. Aspects of the user-friendliness of individual codes were also considered. The benchmark studies have benefited participating organisations by providing a means of verifying current codes, and have provided problem data sets by which future models may be compared. (author)

  10. Theoretical chemistry advances and perspectives

    CERN Document Server

    Eyring, Henry

    1980-01-01

    Theoretical Chemistry: Advances and Perspectives, Volume 5 covers articles concerning all aspects of theoretical chemistry. The book discusses the mean spherical approximation for simple electrolyte solutions; the representation of lattice sums as Mellin-transformed products of theta functions; and the evaluation of two-dimensional lattice sums by number theoretic means. The text also describes an application of contour integration; a lattice model of quantum fluid; as well as the computational aspects of chemical equilibrium in complex systems. Chemists and physicists will find the book usef

  11. The IUPAC aqueous and non-aqueous experimental pKa data repositories of organic acids and bases.

    Science.gov (United States)

    Slater, Anthony Michael

    2014-10-01

    Accurate and well-curated experimental pKa data of organic acids and bases in both aqueous and non-aqueous media are invaluable in many areas of chemical research, including pharmaceutical, agrochemical, specialty chemical and property prediction research. In pharmaceutical research, pKa data are relevant in ligand design, protein binding, absorption, distribution, metabolism, elimination as well as solubility and dissolution rate. The pKa data compilations of the International Union of Pure and Applied Chemistry, originally in book form, have been carefully converted into computer-readable form, with value being added in the process, in the form of ionisation assignments and tautomer enumeration. These compilations offer a broad range of chemistry in both aqueous and non-aqueous media and the experimental conditions and original reference for all pKa determinations are supplied. The statistics for these compilations are presented and the utility of the computer-readable form of these compilations is examined in comparison to other pKa compilations. Finally, information is provided about how to access these databases.

  12. Workshop report on large-scale matrix diagonalization methods in chemistry theory institute

    Energy Technology Data Exchange (ETDEWEB)

    Bischof, C.H.; Shepard, R.L.; Huss-Lederman, S. [eds.

    1996-10-01

    The Large-Scale Matrix Diagonalization Methods in Chemistry theory institute brought together 41 computational chemists and numerical analysts. The goal was to understand the needs of the computational chemistry community in problems that utilize matrix diagonalization techniques. This was accomplished by reviewing the current state of the art and looking toward future directions in matrix diagonalization techniques. This institute occurred about 20 years after a related meeting of similar size. During those 20 years the Davidson method continued to dominate the problem of finding a few extremal eigenvalues for many computational chemistry problems. Work on non-diagonally dominant and non-Hermitian problems as well as parallel computing has also brought new methods to bear. The changes and similarities in problems and methods over the past two decades offered an interesting viewpoint for the success in this area. One important area covered by the talks was overviews of the source and nature of the chemistry problems. The numerical analysts were uniformly grateful for the efforts to convey a better understanding of the problems and issues faced in computational chemistry. An important outcome was an understanding of the wide range of eigenproblems encountered in computational chemistry. The workshop covered problems involving self- consistent-field (SCF), configuration interaction (CI), intramolecular vibrational relaxation (IVR), and scattering problems. In atomic structure calculations using the Hartree-Fock method (SCF), the symmetric matrices can range from order hundreds to thousands. These matrices often include large clusters of eigenvalues which can be as much as 25% of the spectrum. However, if Cl methods are also used, the matrix size can be between 10{sup 4} and 10{sup 9} where only one or a few extremal eigenvalues and eigenvectors are needed. Working with very large matrices has lead to the development of

  13. Quality assurance for health and environmental chemistry: 1986

    International Nuclear Information System (INIS)

    Gautier, M.A.; Gladney, E.S.; Moss, W.D.; Phillips, M.B.; O'Malley, B.T.

    1987-11-01

    This report documents the continuing quality assurance efforts of the Health and Environmental Chemistry Group at the Los Alamos National Laboratory. The philosophy, methodology, and computing resources used by the quality assurance program to encompass the diversity of analytical chemistry practiced in the group are described. Included in the report are all quality assurance reference materials used, along with their certified or consensus concentrations, and all analytical chemistry quality assurance measurements made by HSE-9 during 1986. 27 refs., 3 figs

  14. Experimental and computational evidence of halogen bonds involving astatine

    Science.gov (United States)

    Guo, Ning; Maurice, Rémi; Teze, David; Graton, Jérôme; Champion, Julie; Montavon, Gilles; Galland, Nicolas

    2018-03-01

    The importance of halogen bonds—highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base—is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, implying that if this trend continues down the periodic table, astatine should exhibit the highest halogen-bond donating ability. This may be mitigated, however, by the relativistic effects undergone by heavy elements, as illustrated by the metallic character of astatine. Here, the occurrence of halogen-bonding interactions involving astatine is experimentally evidenced. The complexation constants of astatine monoiodide with a series of organic ligands in cyclohexane solution were derived from distribution coefficient measurements and supported by relativistic quantum mechanical calculations. Taken together, the results show that astatine indeed behaves as a halogen-bond donor—a stronger one than iodine—owing to its much more electrophilic σ-hole.

  15. Proceedings of the 3rd international symposium on material chemistry in nuclear environment (MATERIAL CHEMISTRY '02)

    International Nuclear Information System (INIS)

    2003-03-01

    The volume contains all presented papers during the 3rd International Symposium on Material Chemistry in Nuclear Environment: MATERIAL CHEMISTRY 02 (MC'02), held March 13-15, 2002. The purpose of this symposium is to provide an international forum for the discussion of recent progress in the field of materials chemistry in nuclear environments. This symposium intends to build on the success of the previous symposiums held in Tsukuba in 1992 and 1996. The topics discussed in the symposium MC'02 are Chemical Reaction and Thermodynamics, Degradation Phenomena, New Characterization Technology, Fabrication and New Materials, Composite Materials, Surface Modification, and Computational Science. The 61 of the presented papers are indexed individually. (J.P.N.)

  16. Primary water chemistry optimization for extended fuel cycle operation. Results of the 'Duo experimentation' after three cycles

    Energy Technology Data Exchange (ETDEWEB)

    Viricel, L.; Andrieu, C.; Segura, J.C.; Rocher, A. [Electricite de France (France); Thomazet, J.; Clinard, M.H. [Framatome ANP (France); Dacquait, F. [Commissariat a l' Energie Atomique (France)

    2002-07-01

    The primary coolant conditioning in French nuclear power plants is essentially based on the boron-lithium coordinated chemistry, with a target pH of 7.2 at 300 C and a maximum lithium concentration of 2.2 mg/kg. In 1996, EDF 1300 MWe units began operating 18-month fuel cycles, increasing boron concentrations at the beginning of the cycles. Since today the maximum lithium concentration in normal operation is 2.2 mg/kg, extended cycle operation results in a decrease in the pH at the beginning of the cycles, which may possibly lead to deposits in RCS, and particularly on the fuel cladding, and increased dose rates. It has to be noted that today, the fuel assemblies maximum burnup is set at 52 GWd/tU. One solution is to adjust the pH by increasing the lithium content at the beginning of the cycles, which is easy to implement and does not require any modification on the units. Hence, EDF is testing a ''modified'' chemistry regime in the << Duo experimentation >> during 4 fuel cycles, with a maximum authorized lithium content of 3.5 mg/kg at the beginning of the cycles in the Cattenom 2 pilot unit. The Golfech 1 reference unit implements a standard boron-lithium coordination pH{sub 300} 7.2. The major goal of the experimentation is to assess the impact of elevated lithium concentrations at the beginning of the cycles on fuel cladding oxide behavior, mass transport and dose rates. This paper presents the results of the first three cycles of the Duo experimentation. (author)

  17. Validation of thermohydraulic codes by comparison of experimental results with computer simulations

    International Nuclear Information System (INIS)

    Madeira, A.A.; Galetti, M.R.S.; Pontedeiro, A.C.

    1989-01-01

    The results obtained by simulation of three cases from CANON depressurization experience, using the TRAC-PF1 computer code, version 7.6, implanted in the VAX-11/750 computer of Brazilian CNEN, are presented. The CANON experience was chosen as first standard problem in thermo-hydraulic to be discussed at ENFIR for comparing results from different computer codes with results obtained experimentally. The ability of TRAC-PF1 code to prevent the depressurization phase of a loss of primary collant accident in pressurized water reactors is evaluated. (M.C.K.) [pt

  18. Proceedings of the DAE-BRNS fifth interdisciplinary symposium on materials chemistry

    International Nuclear Information System (INIS)

    Jafar, Mohsin; Tyagi, Adish; Tyagi, Deepak

    2014-12-01

    The focus of the present symposium on materials chemistry was on research areas in materials chemistry like: nuclear materials; high purity materials; nanomaterials and clusters; carbon based materials; fuel cell materials and other electro-ceramics; biomaterials; polymers and soft condensed matter; materials for energy conversion; thin films and surface chemistry; magnetic materials; catalysis; chemical sensors; organic and organometallic compounds; computational material chemistry etc. Papers relevant to INIS are indexed separately

  19. User's Guide to Handlens - A Computer Program that Calculates the Chemistry of Minerals in Mixtures

    Science.gov (United States)

    Eberl, D.D.

    2008-01-01

    HandLens is a computer program, written in Excel macro language, that calculates the chemistry of minerals in mineral mixtures (for example, in rocks, soils and sediments) for related samples from inputs of quantitative mineralogy and chemistry. For best results, the related samples should contain minerals having the same chemical compositions; that is, the samples should differ only in the proportions of minerals present. This manual describes how to use the program, discusses the theory behind its operation, and presents test results of the program's accuracy. Required input for HandLens includes quantitative mineralogical data, obtained, for example, by RockJock analysis of X-ray diffraction (XRD) patterns, and quantitative chemical data, obtained, for example, by X-ray florescence (XRF) analysis of the same samples. Other quantitative data, such as sample depth, temperature, surface area, also can be entered. The minerals present in the samples are selected from a list, and the program is started. The results of the calculation include: (1) a table of linear coefficients of determination (r2's) which relate pairs of input data (for example, Si versus quartz weight percents); (2) a utility for plotting all input data, either as pairs of variables, or as sums of up to eight variables; (3) a table that presents the calculated chemical formulae for minerals in the samples; (4) a table that lists the calculated concentrations of major, minor, and trace elements in the various minerals; and (5) a table that presents chemical formulae for the minerals that have been corrected for possible systematic errors in the mineralogical and/or chemical analyses. In addition, the program contains a method for testing the assumption of constant chemistry of the minerals within a sample set.

  20. Synthesis of Ethyl Nalidixate: A Medicinal Chemistry Experiment

    Science.gov (United States)

    Leslie, Ray; Leeb, Elaine; Smith, Robert B.

    2012-01-01

    A series of laboratory experiments that complement a medicinal chemistry lecture course in drug design and development have been developed. The synthesis of ethyl nalidixate covers three separate experimental procedures, all of which can be completed in three, standard three-hour lab classes and incorporate aspects of green chemistry such as…

  1. Kinetic chemistry of dense interstellar clouds

    International Nuclear Information System (INIS)

    Graedel, T.E.; Langer, W.D.; Frerking, M.A.

    1982-01-01

    A detailed model of the time-dependent chemistry of dense interstellar clouds has been developed to study the dominant chemical processes in carbon and oxygen isotope fractionation, formation of nitrogen-containing molecules, evolution of product molecules as a function of cloud density and temperature, and other topics of interest. The full computation involves 328 individual reactions (expanded to 1067 to study carbon and oxygen isotope chemistry); photodegradation processes are unimportant in these dense clouds and are excluded

  2. Progress report, Chemistry and Materials Division, January 1 to March 31, 1977

    International Nuclear Information System (INIS)

    1977-04-01

    Results are described of research on ion penetration, electron microscopy, radiation damage and metal physics, nuclear methods of analysis, computer calculating methods, analytical chemistry, deuterium exchange, radioactivity measurement, electrochemistry, mass spectrometry and fuel analysis, radiation chemistry, surface chemistry, and properties of zirconium base alloys. (E.C.B.)

  3. QUEST FOR TEACHING EXPERIMENTAL SKILLS

    Directory of Open Access Journals (Sweden)

    B. Samrajya LAKSHMI

    2013-01-01

    Full Text Available In Andhra Pradesh, India, chemical experimenting in under graduate college labs by students is neglected because most of the intermediate (10+1 and 10+2 students concentrate on writing competitive exams like EAMCET (Engineering and Medical Common Entrance Test, IIT JEE (Indian Institute of Technology Joint Entrance Test, AIEEE (All India Engineering Entrance Examination, AFMS (Armed Forces Medical Services, AIMS (All India Institute of Medical Science. The students spend most of their time in preparing for competitive exams, practicing bits, and writing many model exams. Even Parents, staff, and management are also motivated and allow the students towards preparation for competitive exams because of the increase in number of engineering seats and demand of medical seats. Ultimately, the quality and quantity of students who join the B.Sc. (Bachelor of Science has been decreasing day by day. Even after joining the B.Sc., the students are motivated towards immediate white collared job oriented courses like M.C.A (Master of Computer Applications and M.B.A (Master Business Administration and spending their time for preparing for competitive exams for those courses. Only a few students are interested to join Post graduation in chemistry and try to learn experimental skills in chemistry laboratory. However, the motivated students towards undergraduate chemistry will be demotivated towards it due to lack of fundamentals in chemistry (in 10+2 level, which are essential for better job market. Ultimately, the students are in confusion and neglect learning the skills in doing experiments in chemistry lab. The present paper focuses on the thorough quest of one such teacher who strives for his own professional development. He has developed his own method of guiding the students for their improvement of skills in doing experiments in lab. The teacher explored solutions to his problems or problems of students by sorting out the critical incidents from his own

  4. The enthalpies of formation of alkyl carbamates: Experimental and computational redetermination

    International Nuclear Information System (INIS)

    Santos, Ana Filipa L.O.M.; Ribeiro da Silva, Manuel A.V.

    2013-01-01

    Highlights: ► Combustion calorimetry was used to redetermine Δ f H m o (cr) of methyl and ethyl carbamates. ► Δ cr g H m o of methyl and ethyl carbamates were redetermined by Calvet Microcalorimetry. ► Gas-phase Δ f H m o of the studied compounds have been derived from the experimental values of Δ f H m o (cr) and Δ cr g H m o . ► Gas-phase Δ f H m o of the studied compounds have been calculated by computational thermochemistry. ► The obtained Δ f H m o (g) for the alkylcarbamates are discussed versus literature values for the same compounds. - Abstract: In the present work, a redetermination of thermochemical data of methyl carbamate and ethyl carbamate was performed by both experimental and computational techniques. Their gas-phase standard (p o = 0.1 MPa) molar enthalpies of formation, Δ f H m o (g), at T = 298.15 K, were derived from the standard molar enthalpies of formation, in the crystalline phase, Δ f H m o (cr), and from the standard molar enthalpies of sublimation, Δ cr g H m o at T = 298.15 K, measured, respectively, by static bomb combustion calorimetry and high temperature Calvet microcalorimetry. The experimental results were compared with computational data, calculated at the G3(MP2)//B3LYP level, as well as with values reported in the literature. At the B3LYP/6-31G(d) level of theory, the molecular structure of both carbamates was obtained.

  5. Modeling of iodine radiation chemistry in the presence of organic compounds

    International Nuclear Information System (INIS)

    Taghipour, Fariborz; Evans, Greg J.

    2002-01-01

    A kinetic-based model was developed that simulates the radiation chemistry of iodine in the presence of organic compounds. The model's mechanistic description of iodine chemistry and generic semi-mechanistic reactions for various classes of organics, provided a reasonable representation of experimental results. The majority of the model and experimental results of iodine volatilization rates were in agreement within an order of magnitude

  6. Defined Host–Guest Chemistry on Nanocarbon for Sustained Inhibition of Cancer

    Science.gov (United States)

    Ostadhossein, Fatemeh; Misra, Santosh K.; Mukherjee, Prabuddha; Ostadhossein, Alireza; Daza, Enrique; Tiwari, Saumya; Mittal, Shachi; Gryka, Mark C.; Bhargava, Rohit

    2017-01-01

    Signal transducer and activator of transcription factor 3 (STAT-3) is known to be overexpressed in cancer stem cells. Poor solubility and variable drug absorption are linked to low bioavailability and decreased efficacy. Many of the drugs regulating STAT-3 expression lack aqueous solubility; hence hindering efficient bioavailability. A theranostics nanoplatform based on luminescent carbon particles decorated with cucurbit[6]uril is introduced for enhancing the solubility of niclosamide, a STAT-3 inhibitor. The host–guest chemistry between cucurbit[6]uril and niclosamide makes the delivery of the hydrophobic drug feasible while carbon nanoparticles enhance cellular internalization. Extensive physicochemical characterizations confirm successful synthesis. Subsequently, the host–guest chemistry of niclosamide and cucurbit[6]uril is studied experimentally and computationally. In vitro assessments in human breast cancer cells indicate approximately twofold enhancement in IC50 of drug. Fourier transform infrared and fluorescence imaging demonstrate efficient cellular internalization. Furthermore, the catalytic biodegradation of the nanoplatforms occur upon exposure to human myeloperoxidase in short time. In vivo studies on athymic mice with MCF-7 xenograft indicate the size of tumor in the treatment group is half of the controls after 40 d. Immunohistochemistry corroborates the downregulation of STAT-3 phosphorylation. Overall, the host–guest chemistry on nanocarbon acts as a novel arsenal for STAT-3 inhibition. PMID:27545321

  7. Experimental and modeling studies of small molecule chemistry in expanding spherical flames

    Science.gov (United States)

    Santner, Jeffrey

    Accurate models of flame chemistry are required in order to predict emissions and flame properties, such that clean, efficient engines can be designed more easily. There are three primary methods used to improve such combustion chemistry models - theoretical reaction rate calculations, elementary reaction rate experiments, and combustion system experiments. This work contributes to model improvement through the third method - measurements and analysis of the laminar burning velocity at constraining conditions. Modern combustion systems operate at high pressure with strong exhaust gas dilution in order to improve efficiency and reduce emissions. Additionally, flames under these conditions are sensitized to elementary reaction rates such that measurements constrain modeling efforts. Measurement conditions of the present work operate within this intersection between applications and fundamental science. Experiments utilize a new pressure-release, heated spherical combustion chamber with a variety of fuels (high hydrogen content fuels, formaldehyde (via 1,3,5-trioxane), and C2 fuels) at pressures from 0.5--25 atm, often with dilution by water vapor or carbon dioxide to flame temperatures below 2000 K. The constraining ability of these measurements depends on their uncertainty. Thus, the present work includes a novel analytical estimate of the effects of thermal radiative heat loss on burning velocity measurements in spherical flames. For 1,3,5-trioxane experiments, global measurements are sufficiently sensitive to elementary reaction rates that optimization techniques are employed to indirectly measure the reaction rates of HCO consumption. Besides the influence of flame chemistry on propagation, this work also explores the chemistry involved in production of nitric oxide, a harmful pollutant, within flames. We find significant differences among available chemistry models, both in mechanistic structure and quantitative reaction rates. There is a lack of well

  8. Effect of Peer-Led Team Learning (PLTL) on Student Achievement, Attitude, and Self-Concept in College General Chemistry in Randomized and Quasi Experimental Designs

    Science.gov (United States)

    Chan, Julia Y. K.; Bauer, Christopher F.

    2015-01-01

    This study investigated exam achievement and affective characteristics of students in general chemistry in a fully-randomized experimental design, contrasting Peer-Led Team Learning (PLTL) participation with a control group balanced for time-on-task and study activity. This study population included two independent first-semester courses with…

  9. Experimental design a chemometric approach

    CERN Document Server

    Deming, SN

    1987-01-01

    Now available in a paperback edition is a book which has been described as ``...an exceptionally lucid, easy-to-read presentation... would be an excellent addition to the collection of every analytical chemist. I recommend it with great enthusiasm.'' (Analytical Chemistry). Unlike most current textbooks, it approaches experimental design from the point of view of the experimenter, rather than that of the statistician. As the reviewer in `Analytical Chemistry' went on to say: ``Deming and Morgan should be given high praise for bringing the principles of experimental design to the level of the p

  10. Video analysis of projectile motion using tablet computers as experimental tools

    Science.gov (United States)

    Klein, P.; Gröber, S.; Kuhn, J.; Müller, A.

    2014-01-01

    Tablet computers were used as experimental tools to record and analyse the motion of a ball thrown vertically from a moving skateboard. Special applications plotted the measurement data component by component, allowing a simple determination of initial conditions and g in order to explore the underlying laws of motion. This experiment can easily be performed by students themselves, providing more autonomy in their problem-solving processes than traditional learning approaches. We believe that this autonomy and the authenticity of the experimental tool both foster their motivation.

  11. Vortex-Concept for Radioactivity Release Prevention at NPP: Development of Computational Model of Lab-Scale Experimental Setup

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Sana; Sung, Yim Man; Park, Jin Soo; Sung Hyung Jin [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The experimental validation of the vortex-like air curtain concept and use of an appropriate CFD modelling approach for analyzing the problem becomes crucial. A lab-scale experimental setup is designed to validate the proposed concept and CFD modeling approach as a part of validation process. In this study, a computational model of this lab-scale experiment setup is developed using open source CFD code OpenFOAM. The computational results will be compared with experimental data for validation purposes in future, when experimental data is available. 1) A computation model of a lab-scale experimental setup, designed to validate the concept of artificial vortex-like airflow generation for application to radioactivity dispersion prevention in the event of severe accident, was developed. 2) The mesh sensitivity study was performed and a mesh of about 2 million cells was found to be sufficient for this setup.

  12. An Educational Approach to Computationally Modeling Dynamical Systems

    Science.gov (United States)

    Chodroff, Leah; O'Neal, Tim M.; Long, David A.; Hemkin, Sheryl

    2009-01-01

    Chemists have used computational science methodologies for a number of decades and their utility continues to be unabated. For this reason we developed an advanced lab in computational chemistry in which students gain understanding of general strengths and weaknesses of computation-based chemistry by working through a specific research problem.…

  13. Computer network for experimental research using ISDN

    International Nuclear Information System (INIS)

    Ida, Katsumi; Nakanishi, Hideya

    1997-01-01

    This report describes the development of a computer network that uses the Integrated Service Digital Network (ISDN) for real-time analysis of experimental plasma physics and nuclear fusion research. Communication speed, 64/128kbps (INS64) or 1.5Mbps (INS1500) per connection, is independent of how busy the network is. When INS-1500 is used, the communication speed, which is proportional to the public telephone connection fee, can be dynamically varied from 64kbps to 1472kbps (depending on how much data are being transferred using the Bandwidth-on-Demand (BOD) function in the ISDN Router. On-demand dial-up and time-out disconnection reduce the public telephone connection fee by 10%-97%. (author)

  14. Computational medicinal chemistry in fragment-based drug discovery: what, how and when.

    Science.gov (United States)

    Rabal, Obdulia; Urbano-Cuadrado, Manuel; Oyarzabal, Julen

    2011-01-01

    The use of fragment-based drug discovery (FBDD) has increased in the last decade due to the encouraging results obtained to date. In this scenario, computational approaches, together with experimental information, play an important role to guide and speed up the process. By default, FBDD is generally considered as a constructive approach. However, such additive behavior is not always present, therefore, simple fragment maturation will not always deliver the expected results. In this review, computational approaches utilized in FBDD are reported together with real case studies, where applicability domains are exemplified, in order to analyze them, and then, maximize their performance and reliability. Thus, a proper use of these computational tools can minimize misleading conclusions, keeping the credit on FBDD strategy, as well as achieve higher impact in the drug-discovery process. FBDD goes one step beyond a simple constructive approach. A broad set of computational tools: docking, R group quantitative structure-activity relationship, fragmentation tools, fragments management tools, patents analysis and fragment-hopping, for example, can be utilized in FBDD, providing a clear positive impact if they are utilized in the proper scenario - what, how and when. An initial assessment of additive/non-additive behavior is a critical point to define the most convenient approach for fragments elaboration.

  15. Instrumentation, computer software and experimental techniques used in low-frequency internal friction studies at WNRE

    International Nuclear Information System (INIS)

    Sprugmann, K.W.; Ritchie, I.G.

    1980-04-01

    A detailed and comprehensive account of the equipment, computer programs and experimental methods developed at the Whiteshell Nuclear Research Estalbishment for the study of low-frequency internal friction is presented. Part 1 describes the mechanical apparatus, electronic instrumentation and computer software, while Part II describes in detail the laboratory techniques and various types of experiments performed together with data reduction and analysis. Experimental procedures for the study of internal friction as a function of temperature, strain amplitude or time are described. Computer control of these experiments using the free-decay technique is outlined. In addition, a pendulum constant-amplitude drive system is described. (auth)

  16. Calibration of uncertain inputs to computer models using experimentally measured quantities and the BMARS emulator

    International Nuclear Information System (INIS)

    Stripling, H.F.; McClarren, R.G.; Kuranz, C.C.; Grosskopf, M.J.; Rutter, E.; Torralva, B.R.

    2011-01-01

    We present a method for calibrating the uncertain inputs to a computer model using available experimental data. The goal of the procedure is to produce posterior distributions of the uncertain inputs such that when samples from the posteriors are used as inputs to future model runs, the model is more likely to replicate (or predict) the experimental response. The calibration is performed by sampling the space of the uncertain inputs, using the computer model (or, more likely, an emulator for the computer model) to assign weights to the samples, and applying the weights to produce the posterior distributions and generate predictions of new experiments within confidence bounds. The method is similar to the Markov chain Monte Carlo (MCMC) calibration methods with independent sampling with the exception that we generate samples beforehand and replace the candidate acceptance routine with a weighting scheme. We apply our method to the calibration of a Hyades 2D model of laser energy deposition in beryllium. We employ a Bayesian Multivariate Adaptive Regression Splines (BMARS) emulator as a surrogate for Hyades 2D. We treat a range of uncertainties in our system, including uncertainties in the experimental inputs, experimental measurement error, and systematic experimental timing errors. The results of the calibration are posterior distributions that both agree with intuition and improve the accuracy and decrease the uncertainty in experimental predictions. (author)

  17. A Comparison of Computed and Experimental Flowfields of the RAH-66 Helicopter

    Science.gov (United States)

    vanDam, C. P.; Budge, A. M.; Duque, E. P. N.

    1996-01-01

    This paper compares and evaluates numerical and experimental flowfields of the RAH-66 Comanche helicopter. The numerical predictions were obtained by solving the Thin-Layer Navier-Stokes equations. The computations use actuator disks to investigate the main and tail rotor effects upon the fuselage flowfield. The wind tunnel experiment was performed in the 14 x 22 foot facility located at NASA Langley. A suite of flow conditions, rotor thrusts and fuselage-rotor-tail configurations were tested. In addition, the tunnel model and the computational geometry were based upon the same CAD definition. Computations were performed for an isolated fuselage configuration and for a rotor on configuration. Comparisons between the measured and computed surface pressures show areas of correlation and some discrepancies. Local areas of poor computational grid-quality and local areas of geometry differences account for the differences. These calculations demonstrate the use of advanced computational fluid dynamic methodologies towards a flight vehicle currently under development. It serves as an important verification for future computed results.

  18. Industrial medicinal chemistry insights: neuroscience hit generation at Janssen.

    Science.gov (United States)

    Tresadern, Gary; Rombouts, Frederik J R; Oehlrich, Daniel; Macdonald, Gregor; Trabanco, Andres A

    2017-10-01

    The role of medicinal chemistry has changed over the past 10 years. Chemistry had become one step in a process; funneling the output of high-throughput screening (HTS) on to the next stage. The goal to identify the ideal clinical compound remains, but the means to achieve this have changed. Modern medicinal chemistry is responsible for integrating innovation throughout early drug discovery, including new screening paradigms, computational approaches, novel synthetic chemistry, gene-family screening, investigating routes of delivery, and so on. In this Foundation Review, we show how a successful medicinal chemistry team has a broad impact and requires multidisciplinary expertise in these areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Development and Application of Computational/In Vitro Toxicological Methods for Chemical Hazard Risk Reduction of New Materials for Advanced Weapon Systems

    Science.gov (United States)

    Frazier, John M.; Mattie, D. R.; Hussain, Saber; Pachter, Ruth; Boatz, Jerry; Hawkins, T. W.

    2000-01-01

    The development of quantitative structure-activity relationship (QSAR) is essential for reducing the chemical hazards of new weapon systems. The current collaboration between HEST (toxicology research and testing), MLPJ (computational chemistry) and PRS (computational chemistry, new propellant synthesis) is focusing R&D efforts on basic research goals that will rapidly transition to useful products for propellant development. Computational methods are being investigated that will assist in forecasting cellular toxicological end-points. Models developed from these chemical structure-toxicity relationships are useful for the prediction of the toxicological endpoints of new related compounds. Research is focusing on the evaluation tools to be used for the discovery of such relationships and the development of models of the mechanisms of action. Combinations of computational chemistry techniques, in vitro toxicity methods, and statistical correlations, will be employed to develop and explore potential predictive relationships; results for series of molecular systems that demonstrate the viability of this approach are reported. A number of hydrazine salts have been synthesized for evaluation. Computational chemistry methods are being used to elucidate the mechanism of action of these salts. Toxicity endpoints such as viability (LDH) and changes in enzyme activity (glutahoione peroxidase and catalase) are being experimentally measured as indicators of cellular damage. Extrapolation from computational/in vitro studies to human toxicity, is the ultimate goal. The product of this program will be a predictive tool to assist in the development of new, less toxic propellants.

  20. Virtual drug discovery: beyond computational chemistry?

    Science.gov (United States)

    Gilardoni, Francois; Arvanites, Anthony C

    2010-02-01

    This editorial looks at how a fully integrated structure that performs all aspects in the drug discovery process, under one company, is slowly disappearing. The steps in the drug discovery paradigm have been slowly increasing toward virtuality or outsourcing at various phases of product development in a company's candidate pipeline. Each step in the process, such as target identification and validation and medicinal chemistry, can be managed by scientific teams within a 'virtual' company. Pharmaceutical companies to biotechnology start-ups have been quick in adopting this new research and development business strategy in order to gain flexibility, access the best technologies and technical expertise, and decrease product developmental costs. In today's financial climate, the term virtual drug discovery has an organizational meaning. It represents the next evolutionary step in outsourcing drug development.

  1. Computational and experimental analyses of the wave propagation through a bar structure including liquid-solid interface

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Jin [UST Graduate School, Daejeon (Korea, Republic of); Rhee, Hui Nam [Division of Mechanical and Aerospace Engineering, Sunchon National University, Sunchon (Korea, Republic of); Yoon, Doo Byung; Park, Jin Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-08-15

    In this research, we study the propagation of longitudinal and transverse waves through a metal rod including a liquid layer using computational and experimental analyses. The propagation characteristics of longitudinal and transverse waves obtained by the computational and experimental analyses were consistent with the wave propagation theory for both cases, that is, the homogeneous metal rod and the metal rod including a liquid layer. The fluid-structure interaction modeling technique developed for the computational wave propagation analysis in this research can be applied to the more complex structures including solid-liquid interfaces.

  2. Effects of Ichthyophonus hoferi on condition indices and blood chemistry of experimentally infected rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Rand, T G; Cone, D K

    1990-07-01

    Body condition, hepatosomatic index and blood chemistry of Oncorhynchus mykiss experimentally infected with a tissue dwelling fish pathogenic fungus, Ichthyophonus hoferi, were monitored over a 6 wk period. This was to determine whether the infection constituted a stress manifest by changes in the hypothalamic-pituitary interrenal axis, and especially plasma cortisol levels. Infection caused anaemia and leucopenia but did not change the condition, hepatosomatic indices, or plasma chloride, cholesterol, cortisol, creatinine, glucose, osmolarity, potassium, total protein, sodium and T4. It is suggested that increased cortisol levels may not be a normal component of the stress response of fish to disease caused by invasive infectious agents.

  3. Cellular burning in lean premixed turbulent hydrogen-air flames: Coupling experimental and computational analysis at the laboratory scale

    International Nuclear Information System (INIS)

    Day, M S; Bell, J B; Beckner, V E; Lijewski, M J; Cheng, R K; Tachibana, S

    2009-01-01

    One strategy for reducing US dependence on petroleum is to develop new combustion technologies for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification of coal and biomass. Fuel-flexible combustion systems based on lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat and stationary power generation. However, lean premixed flames are highly susceptible to fluid-dynamical combustion instabilities making robust and reliable systems difficult to design. Low swirl burners are emerging as an important technology for meeting design requirements in terms of both reliability and emissions for next generation combustion devices. In this paper, we present simulations of a lean, premixed hydrogen flame stabilized on a laboratory-scale low swirl burner. The simulations use detailed chemistry and transport without incorporating explicit models for turbulence or turbulence/chemistry interaction. Here we discuss the overall structure of the flame and compare with experimental data. We also use the simulation data to elucidate the characteristics of the turbulent flame interaction and how this impacts the analysis of experimental measurements.

  4. Quality assurance for health and environmental chemistry: 1989

    International Nuclear Information System (INIS)

    Gautier, M.A.; Gladney, E.S.; Koski, N.L.; Jones, E.A.; Phillips, M.B.; O'Malley, B.T.

    1990-12-01

    This report documents the continuing quality assurance efforts of the Health and Environmental Chemistry Group (HSE-9) at the Los Alamos National Laboratory. The philosophy, methodology, computing resources, and laboratory information management system used by the quality assurance program to encompass the diversity of analytical chemistry practiced in the group are described. Included in the report are all quality assurance reference materials used, along with their certified or consensus concentrations, and all analytical chemistry quality assurance measurements made by HSE-9 during 1989. 38 refs., 8 figs., 3 tabs

  5. Computer techniques for experimental work in GDR nuclear power plants with WWER

    International Nuclear Information System (INIS)

    Stemmler, G.

    1985-01-01

    Nuclear power plant units with WWER are being increasingly equipped with high-performance, programmable process control computers. There are, however, essential reasons for further advancing the development of computer-aided measuring systems, in particular for experimental work. A special structure of such systems, which is based on the division into relatively rigid data registration and primary handling and into further processing by advanced programming language, has proved useful in the GDR. (author)

  6. Experimental and computational investigations of heat and mass transfer of intensifier grids

    International Nuclear Information System (INIS)

    Kobzar, Leonid; Oleksyuk, Dmitry; Semchenkov, Yuriy

    2015-01-01

    The paper discusses experimental and numerical investigations on intensification of thermal and mass exchange which were performed by National Research Centre ''Kurchatov Institute'' over the past years. Recently, many designs of heat mass transfer intensifier grids have been proposed. NRC ''Kurchatov Institute'' has accomplished a large scope of experimental investigations to study efficiency of intensifier grids of various types. The outcomes of experimental investigations can be used in verification of computational models and codes. On the basis of experimental data, we derived correlations to calculate coolant mixing and critical heat flux mixing in rod bundles equipped with intensifier grids. The acquired correlations were integrated in subchannel code SC-INT.

  7. Dichloro-Cycloazatriphosphane: The Missing Link between N2 P2 and P4 Ring Systems in the Systematic Development of NP Chemistry.

    Science.gov (United States)

    Bresien, Jonas; Hinz, Alexander; Schulz, Axel; Suhrbier, Tim; Thomas, Max; Villinger, Alexander

    2017-10-20

    A dichloro-cycloazatriphosphane that incorporates a cyclic NP 3 backbone could be synthesized using knowledge gained from the chemistry of N 2 P 2 and P 4 ring systems. It fills the gap between the congeneric compounds [ClP(μ-NR)] 2 and [ClP(μ-PR)] 2 (R=sterically demanding substituent), and thus contributes to the systematic development of nitrogen-phosphorus chemistry in general. The title compound was studied with respect to its formation via a labile aminodiphosphene, which readily underwent different rearrangement reactions depending on the solvent. All compounds were fully characterized by experimental and computational methods. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Mathematics for physical chemistry

    CERN Document Server

    Mortimer, Robert G

    2005-01-01

    Mathematics for Physical Chemistry, Third Edition, is the ideal text for students and physical chemists who want to sharpen their mathematics skills. It can help prepare the reader for an undergraduate course, serve as a supplementary text for use during a course, or serve as a reference for graduate students and practicing chemists. The text concentrates on applications instead of theory, and, although the emphasis is on physical chemistry, it can also be useful in general chemistry courses. The Third Edition includes new exercises in each chapter that provide practice in a technique immediately after discussion or example and encourage self-study. The first ten chapters are constructed around a sequence of mathematical topics, with a gradual progression into more advanced material. The final chapter discusses mathematical topics needed in the analysis of experimental data.* Numerous examples and problems interspersed throughout the presentations * Each extensive chapter contains a preview, objectives, and ...

  9. Effectiveness of student learning during experimental work in primary school

    OpenAIRE

    Logar, Ana; Peklaj, Cirila; Ferk Savec, Vesna

    2017-01-01

    The aim of the research was to optimize the effectiveness of student learning based on experimental work in chemistry classes in Slovenian primary schools. To obtain evidence about how experimental work is implemented during regular chemistry classes, experimental work was videotaped during 19 units of chemistry lessons at 12 Slovenian primary schools from the pool of randomly selected schools. Altogether 332 eight-grade students were involved in the investigation, with an average...

  10. Evaluating the efficacy of a chemistry video game

    Science.gov (United States)

    Shapiro, Marina

    A quasi-experimental design pre-test/post-test intervention study utilizing a within group analysis was conducted with 45 undergraduate college chemistry students that investigated the effect of implementing a game-based learning environment into an undergraduate college chemistry course in order to learn if serious educational games (SEGs) can be used to achieve knowledge gains of complex chemistry concepts and to achieve increase in students' positive attitude toward chemistry. To evaluate if students learn chemistry concepts by participating in a chemistry game-based learning environment, a one-way repeated measures analysis of variance (ANOVA) was conducted across three time points (pre-test, post-test, delayed post-test which were chemistry content exams). Results showed that there was an increase in exam scores over time. The results of the ANOVA indicated a statistically significant time effect. To evaluate if students' attitude towards chemistry increased as a result of participating in a chemistry game-based learning environment a paired samples t-test was conducted using a chemistry attitudinal survey by Mahdi (2014) as the pre- and post-test. Results of the paired-samples t-test indicated that there was no significant difference in pre-attitudinal scores and post-attitudinal scores.

  11. Preface to special issue of selected papers from Theoretical, Experimental, and Computational Mechanics (TECM)

    DEFF Research Database (Denmark)

    Jabbari, Masoud; Sarlak Chivaee, Hamid; Hattel, Jesper Henri

    2017-01-01

    We are pleased to introduce this special issue of the Applied Mathematical Modelling journal with highlights from theTheoretical, Experimental, and Computational Mechanics Symposium (TECM-2015). This special issue consists of four rigorouslyselected papers originally presented at TECM-2015...... as a part of the 13th International Conference of Numerical Analysisand Applied Mathematics 2015 (ICNAAM 2015), which was held on 23-29 September 2015 in Rhodes, Greece.The symposium attracted a broad range of international and local leaders in theoretical, experimental, and computational mechanics across...... various fields and application. The symposium did an excellent job of outlining the current landscape of computational mechanics and its capabilities in solving complex industrial problems in the process industries, and we agree with the editor-in-chief of the journal that it is certainly worthwhile...

  12. Surveys of research in the Chemistry Division, Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Grazis, B.M. [ed.

    1992-11-01

    Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

  13. Surveys of research in the Chemistry Division, Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Grazis, B.M. (ed.)

    1992-01-01

    Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

  14. Fundamental R and D program on water chemistry of supercritical pressure water under radiation field

    International Nuclear Information System (INIS)

    Katsumura, Yosuke; Kiuchi, Kiyoshi; Wada, Yoichi; Yotsuyanagi, Tadasu

    2003-01-01

    In a supercritical water-cooled reactor, property of water changes significantly around the critical point. It is expected that irradiation and change of water property will affect the chemistry and material corrosion. Deep understanding of interactions between supercritical water and materials under irradiation is important. However, comprehensive data on radiolysis, kinetics, corrosion and thermodynamics have not been obtained due to the severe experimental condition. To get such data by experiments and computer simulations, a national program funded by Ministry of Education, Culture, Sports, Science and Technology (MEXT) has been started since December 2002. (author)

  15. Computer controlled quality of analytical measurements

    International Nuclear Information System (INIS)

    Clark, J.P.; Huff, G.A.

    1979-01-01

    A PDP 11/35 computer system is used in evaluating analytical chemistry measurements quality control data at the Barnwell Nuclear Fuel Plant. This computerized measurement quality control system has several features which are not available in manual systems, such as real-time measurement control, computer calculated bias corrections and standard deviation estimates, surveillance applications, evaluaton of measurement system variables, records storage, immediate analyst recertificaton, and the elimination of routine analysis of known bench standards. The effectiveness of the Barnwell computer system has been demonstrated in gathering and assimilating the measurements of over 1100 quality control samples obtained during a recent plant demonstration run. These data were used to determine equaitons for predicting measurement reliability estimates (bias and precision); to evaluate the measurement system; and to provide direction for modification of chemistry methods. The analytical chemistry measurement quality control activities represented 10% of the total analytical chemistry effort

  16. Nitrogen Compounds in Radiation Chemistry

    International Nuclear Information System (INIS)

    Sims, H.E.; Dey, G.R.; Vaudey, C.E.; Peaucelle, C.; Boucher, J.L.; Toulhoat, N.; Bererd, N.; Koppenol, W.H.; Janata, E.; Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C.

    2009-01-01

    Water radiolysis in presence of N 2 is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N 2 and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO 2 - and NO 3 -. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N 2 O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

  17. Radiation chemistry of the liquid state

    International Nuclear Information System (INIS)

    Buxton, G.V.

    1987-01-01

    More is known about the radiation chemistry of water than any other liquid. From a practical viewpoint out knowledge is virtually complete, and water radiolysis now provides a very convenient way of generating an enormous variety of unstable species under well-defined conditions. This facility, coupled with the techniques of pulse radiolysis, has opened up new areas in aqueous inorganic, organic, and biochemistry that cannot be readily studied by thermal or photochemical methods. This chapter is aimed, therefore, at those who wish to use radiolytic methods to generate and study unstable species in aqueous solution. The basic features of the radiation chemistry of water are described first to show how the primary radical and molecular products evolve with time and to delineate the bounds of useful experimental conditions. Next, the properties of the primary radicals are summarized, and examples are given to show how the primary radicals can be converted into secondary radicals, often of a single kind. This is an important aspect of the radiation chemistry of aqueous solutions. Lastly, the impact of our knowledge of the radiation chemistry of water on advances in general chemistry is illustrated by examples from the fields of inorganic and organic chemistry

  18. Video Analysis of Projectile Motion Using Tablet Computers as Experimental Tools

    Science.gov (United States)

    Klein, P.; Gröber, S.; Kuhn, J.; Müller, A.

    2014-01-01

    Tablet computers were used as experimental tools to record and analyse the motion of a ball thrown vertically from a moving skateboard. Special applications plotted the measurement data component by component, allowing a simple determination of initial conditions and "g" in order to explore the underlying laws of motion. This experiment…

  19. Combining research in physical chemistry and chemical education: Part A. The femtosecond molecular dynamics of small gas-phase anion clusters. Part B. Surveying student beliefs about chemistry and the development of physical chemistry learning tutorials

    Science.gov (United States)

    Barbera, Jack

    2007-12-01

    This dissertation combines work in the areas of experimental physical chemistry and chemical education. In the area of physical chemistry, femtosecond pump-probe spectroscopy is used to interrogate the time-dependence for energy redistribution, solvent reorientation, and dissociation dynamics in small gas-phase anion clusters. The chemical education research addressed in this manuscript include the development and validation of a survey to measure students' beliefs about chemistry and the learning of chemistry and the development and testing of learning tutorials for use in undergraduate physical chemistry courses in thermodynamics and kinetics. In the first part of this dissertation, the Cu(CD3OD) dynamics are investigated using a combination of femtosecond pump-probe experiments and ab initio calculations. Dissociation of this complex into Cu and CD3OD occurs on two distinct time scales: 3 and 30 ps, which arise, respectively, from the coupling of intermolecular solvent rotations and excited methyl rotor rotation into the Cu-O dissociation component upon electron photodetachment of the precursor anion. In the second part of this dissertation, the time-resolved recombination of photodissociated IBr-(CO2)n (n = 5 - 10) cluster anions is investigated. Upon excitation to the A' 2pi 1/2 state of the chromophore, the bare anion results in I- and Br products, upon solvation with CO2, the IBr- chromophore regains near-IR absorption after recombination and vibrational relaxation on the ground electronic state. The recombination times vary with the number of solvent molecules from 12 ps for n = 5 to 900 ps for n = 10. Extensive electronic structure and non-adiabatic molecular dynamic simulations provide a framework to understand this behavior. In the third part of this dissertation, the modification and validation of the Colorado Learning Attitudes about Science Survey (CLASS) for use in chemistry is presented in detail. The CLASS survey is designed to measure student

  20. Modeling an Excitable Biosynthetic Tissue with Inherent Variability for Paired Computational-Experimental Studies.

    Directory of Open Access Journals (Sweden)

    Tanmay A Gokhale

    2017-01-01

    Full Text Available To understand how excitable tissues give rise to arrhythmias, it is crucially necessary to understand the electrical dynamics of cells in the context of their environment. Multicellular monolayer cultures have proven useful for investigating arrhythmias and other conduction anomalies, and because of their relatively simple structure, these constructs lend themselves to paired computational studies that often help elucidate mechanisms of the observed behavior. However, tissue cultures of cardiomyocyte monolayers currently require the use of neonatal cells with ionic properties that change rapidly during development and have thus been poorly characterized and modeled to date. Recently, Kirkton and Bursac demonstrated the ability to create biosynthetic excitable tissues from genetically engineered and immortalized HEK293 cells with well-characterized electrical properties and the ability to propagate action potentials. In this study, we developed and validated a computational model of these excitable HEK293 cells (called "Ex293" cells using existing electrophysiological data and a genetic search algorithm. In order to reproduce not only the mean but also the variability of experimental observations, we examined what sources of variation were required in the computational model. Random cell-to-cell and inter-monolayer variation in both ionic conductances and tissue conductivity was necessary to explain the experimentally observed variability in action potential shape and macroscopic conduction, and the spatial organization of cell-to-cell conductance variation was found to not impact macroscopic behavior; the resulting model accurately reproduces both normal and drug-modified conduction behavior. The development of a computational Ex293 cell and tissue model provides a novel framework to perform paired computational-experimental studies to study normal and abnormal conduction in multidimensional excitable tissue, and the methodology of modeling

  1. Teachers and Students' Conceptions of Computer-Based Models in the Context of High School Chemistry: Elicitations at the Pre-intervention Stage

    Science.gov (United States)

    Waight, Noemi; Gillmeister, Kristina

    2014-04-01

    This study examined teachers' and students' initial conceptions of computer-based models—Flash and NetLogo models—and documented how teachers and students reconciled notions of multiple representations featuring macroscopic, submicroscopic and symbolic representations prior to actual intervention in eight high school chemistry classrooms. Individual in-depth interviews were conducted with 32 students and 6 teachers. Findings revealed an interplay of complex factors that functioned as opportunities and obstacles in the implementation of technologies in science classrooms. Students revealed preferences for the Flash models as opposed to the open-ended NetLogo models. Altogether, due to lack of content and modeling background knowledge, students experienced difficulties articulating coherent and blended understandings of multiple representations. Concurrently, while the aesthetic and interactive features of the models were of great value, they did not sustain students' initial curiosity and opportunities to improve understandings about chemistry phenomena. Most teachers recognized direct alignment of the Flash model with their existing curriculum; however, the benefits were relegated to existing procedural and passive classroom practices. The findings have implications for pedagogical approaches that address the implementation of computer-based models, function of models, models as multiple representations and the role of background knowledge and cognitive load, and the role of teacher vision and classroom practices.

  2. Contribution from philosophy of chemistry to chemistry education: In a case of ionic liquids as technochemistry

    Science.gov (United States)

    Mudzakir, Ahmad; Hernani, Widhiyanti, Tuszie; Sudrajat, Devi Pratiwi

    2017-08-01

    Traditional chemistry education is commonly handing down of concepts, principles, and theories, such as mechanical properties, the relationship between structure and properties as well as chemical structure and chemical bonding theory, to students without engaging them in the processes of chemical inquiry. This practice leads to the lack of opportunity for the students to construct an appropriate understanding of these concepts, principles, and theories. Students are also rarely facilitated in modeling the structure and function of matter themselves. This situation shows that the philosophy of chemistry has not received as much attention from chemistry educators. The main idea of this paper is to embed philosophy of chemistry through the implementation of technochemistry in chemistry education. One of the most interesting and rapidly developing areas of modern chemistry, technologies and engineering is Ionic Liquids (ILs) as an emerging knowledge on technochemistry which can be applied to chemistry education. The developments between academic researchers and industrial developments in the ILs area are conducted in parallel. In order to overcome the existing problems of scientific development in chemistry education, the science and technology of ILs can be used for reconceptualizing the teaching and learning of chemistry to embrace the epistemology in chemistry. This study promises a potential contribution by philosophy of chemistry. The main objectives of this study are to develop: (i) a perspective based on philosophy of science considerations (rational reconstruction) in order to understand ionic liquids and (ii) teaching materials that can be used to enhance pre-service teacher's view of nature of science and technology (VNOST). The method used in the study is analytical-descriptive (elementarization), i.e. the first step in the model of educational reconstruction (MER). This study concludes that the development of the concepts and their applications of ionic

  3. DIWA trademark. AREVA's approach of intelligent computer-aided support of water chemistry monitoring in power plants

    International Nuclear Information System (INIS)

    Fandrich, Joerg

    2011-01-01

    The complexity of power plant operation makes stringent demands on the chemical quality of the coolant in process systems and loops. Optimal water chemistry ensures high corrosion resistance of these systems and is thus essential for safe and economic long term plant operation. The market offers a huge variety of commercial software packages for water chemistry control. Most of these computer programs have to be considered as data analysis or, respectively, data acquisition programs. Some of them require manual data input (Laboratory Information Management Systems), others are capable of performing a fully automated data acquisition. However, the plant operator typically is left alone with the actual interpretation of all collected and validated data, which would be the main characteristic feature of an analysis (or monitoring) system. The data validation is typical being performed by means of numerical methods in the broadest sense. This activity requires a long working experience and specific skills by the plant chemistry operator. True diagnostic systems need to be significantly more advanced. They contain the capability of data interpretation and derivation of specific diagnoses. This is combined with additional explanations on how the diagnoses were derived. Additionally, further recommendations are offered on how to proceed to reach the normal operational behavior as soon as possible. AREVA's DIWA trademark system features a fuzzy logic expert system that is based on expert knowledge. It is built on symptoms, which are combined in rules as part of the fuzzy tool set. These components can be edited without programming knowledge, which significantly reduces training efforts. It makes the system more robust, more compact and simpler compared to other so-called expert systems. DIWA trademark represents the knowledge in a natural way, in which other conventional expert system may have difficulties or need a larger set of rule algorithms. (orig.)

  4. NWFSC OA facility water chemistry - Ocean acidification species exposure experimental facility

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We have developed a unique facility for conducting high-quality experiments on marine organisms in seawater with controlled carbon chemistry conditions. The...

  5. Modeling the atmospheric chemistry of TICs

    Science.gov (United States)

    Henley, Michael V.; Burns, Douglas S.; Chynwat, Veeradej; Moore, William; Plitz, Angela; Rottmann, Shawn; Hearn, John

    2009-05-01

    An atmospheric chemistry model that describes the behavior and disposition of environmentally hazardous compounds discharged into the atmosphere was coupled with the transport and diffusion model, SCIPUFF. The atmospheric chemistry model was developed by reducing a detailed atmospheric chemistry mechanism to a simple empirical effective degradation rate term (keff) that is a function of important meteorological parameters such as solar flux, temperature, and cloud cover. Empirically derived keff functions that describe the degradation of target toxic industrial chemicals (TICs) were derived by statistically analyzing data generated from the detailed chemistry mechanism run over a wide range of (typical) atmospheric conditions. To assess and identify areas to improve the developed atmospheric chemistry model, sensitivity and uncertainty analyses were performed to (1) quantify the sensitivity of the model output (TIC concentrations) with respect to changes in the input parameters and (2) improve, where necessary, the quality of the input data based on sensitivity results. The model predictions were evaluated against experimental data. Chamber data were used to remove the complexities of dispersion in the atmosphere.

  6. Characterization of sodium stibogluconate by online liquid separation cell technology monitored by ICPMS and ESMS and computational chemistry

    DEFF Research Database (Denmark)

    Hansen, Helle Rusz; Hansen, Claus; Kepp, Kasper Planeta

    2008-01-01

    High-performance liquid chromatography (HPLC), mass spectrometry (MS), and computational chemistry has been applied to resolve the composition and structure of the Sb species present in dilutions of Pentostam, a first-line treatment drug against Leishmania parasites. Using HPLC-inductively coupled......(V)-glyconate complexes of various stoichiometry (1:1, 1:2, 1:3, 2:2, 2:3, 2:4, 3:3, 3:4). The 1:1 complex became the most abundant low molecular mass Sb(V) complex with dilution time. A novel mixed-mode chromatographic system was applied in order to separate complexes of various stoichiometry and isomers. Density...

  7. Designing, programming, and optimizing a (small) quantum computer

    Science.gov (United States)

    Svore, Krysta

    In 1982, Richard Feynman proposed to use a computer founded on the laws of quantum physics to simulate physical systems. In the more than thirty years since, quantum computers have shown promise to solve problems in number theory, chemistry, and materials science that would otherwise take longer than the lifetime of the universe to solve on an exascale classical machine. The practical realization of a quantum computer requires understanding and manipulating subtle quantum states while experimentally controlling quantum interference. It also requires an end-to-end software architecture for programming, optimizing, and implementing a quantum algorithm on the quantum device hardware. In this talk, we will introduce recent advances in connecting abstract theory to present-day real-world applications through software. We will highlight recent advancement of quantum algorithms and the challenges in ultimately performing a scalable solution on a quantum device.

  8. Primary water chemistry monitoring from the point of view of radiation build-up

    International Nuclear Information System (INIS)

    Horvath, G.L.; Civin, V.; Pinter, T.

    1997-01-01

    Basic operational principles of a computer code system calculating the primary circuit corrosion product activities based on actual measured plant chemistry data are presented. The code system consists of two parts: FeSolub.prg: calculates the characteristic iron solubilities based on actual primary water chemistry (H 3 BO 3 KOH, ... etc.) and plant load (MW) data. A developed solubility calculation method has been applied fitted to magnetite solubility data of several authors; RADTRAN.exe: calculates primary circuit water and surface corrosion product activities based on results of FeSolub.prg or planned water chemistry data up to the next shutdown. The computer code system is going to be integrated into a general primary water chemistry monitoring and surveillance system. (author). 15 refs, 4 figs, 3 tabs

  9. A computer program to evaluate the experimental data in instrumental multielement neutron activation analysis

    International Nuclear Information System (INIS)

    Greim, L.; Motamedi, K.; Niedergesaess, R.

    1976-01-01

    A computer code evaluating experimental data of neutron activation analysis (NAA) for determination of atomic abundancies is described. The experimental data are, beside a probe designation, the probe weight, irradiation parameters and a Ge(Li)-pulse-height-spectrum from the activity measurement. The organisation of the necessary nuclear data, comprising all methods of activation in reactor-irradiations, is given. Furthermore the automatic evaluation of spectra, the designation of the resulting peaks to nuclei and the calculation of atomic abundancies are described. The complete evaluation of a spectrum with many lines, e.g. 100 lines of 20 nuclei, takes less than 1 minute machine-time on the TR 440 computer. (orig.) [de

  10. Case Studies in Systems Chemistry. Final Report. [Includes Complete Case Study, Carboxylic Acid Equilibria

    Science.gov (United States)

    Fleck, George

    This publication was produced as a teaching tool for college chemistry. The book is a text for a computer-based unit on the chemistry of acid-base titrations, and is designed for use with FORTRAN or BASIC computer systems, and with a programmable electronic calculator, in a variety of educational settings. The text attempts to present computer…

  11. Computer algebra applications

    International Nuclear Information System (INIS)

    Calmet, J.

    1982-01-01

    A survey of applications based either on fundamental algorithms in computer algebra or on the use of a computer algebra system is presented. Recent work in biology, chemistry, physics, mathematics and computer science is discussed. In particular, applications in high energy physics (quantum electrodynamics), celestial mechanics and general relativity are reviewed. (Auth.)

  12. High performance computing in science and engineering Garching/Munich 2016

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Siegfried; Bode, Arndt; Bruechle, Helmut; Brehm, Matthias (eds.)

    2016-11-01

    Computer simulations are the well-established third pillar of natural sciences along with theory and experimentation. Particularly high performance computing is growing fast and constantly demands more and more powerful machines. To keep pace with this development, in spring 2015, the Leibniz Supercomputing Centre installed the high performance computing system SuperMUC Phase 2, only three years after the inauguration of its sibling SuperMUC Phase 1. Thereby, the compute capabilities were more than doubled. This book covers the time-frame June 2014 until June 2016. Readers will find many examples of outstanding research in the more than 130 projects that are covered in this book, with each one of these projects using at least 4 million core-hours on SuperMUC. The largest scientific communities using SuperMUC in the last two years were computational fluid dynamics simulations, chemistry and material sciences, astrophysics, and life sciences.

  13. A novel computational framework for deducing muscle synergies from experimental joint moments

    Directory of Open Access Journals (Sweden)

    Anantharaman eGopalakrishnan

    2014-12-01

    Full Text Available Prior experimental studies have hypothesized the existence of a ‘muscle synergy’ based control scheme for producing limb movements and locomotion in vertebrates. Such synergies have been suggested to consist of fixed muscle grouping schemes with the co-activation of all muscles in a synergy resulting in limb movement. Quantitative representations of these groupings (termed muscle weightings and their control signals (termed synergy controls have traditionally been derived by the factorization of experimentally measured EMG. This study presents a novel approach for deducing these weightings and controls from inverse dynamic joint moments that are computed from an alternative set of experimental measurements – movement kinematics and kinetics. This technique was applied to joint moments for healthy human walking at 0.7 and 1.7 m/s, and two sets of ‘simulated’ synergies were computed based on two different criteria (1 synergies were required to minimize errors between experimental and simulated joint moments in a musculoskeletal model (pure-synergy solution (2 along with minimizing joint moment errors, synergies also minimized muscle activation levels (optimal-synergy solution. On comparing the two solutions, it was observed that the introduction of optimality requirements (optimal-synergy to a control strategy solely aimed at reproducing the joint moments (pure-synergy did not necessitate major changes in the muscle grouping within synergies or the temporal profiles of synergy control signals. Synergies from both the simulated solutions exhibited many similarities to EMG derived synergies from a previously published study, thus implying that the analysis of the two different types of experimental data reveals similar, underlying synergy structures.

  14. Atmosphere physics and chemistry

    International Nuclear Information System (INIS)

    Delmas, R.; Megie, G.; Peuch, V.H.

    2005-10-01

    Since the 1970's, the awareness about the atmospheric pollution threat has led to a spectacular development of the researches on the complex interactions between the chemical composition of the atmosphere and the climate. This book makes a synthesis of the state-of-the-art in this very active domain of research. Content: introduction, atmosphere dynamics and transport, matter-radiation interaction and radiant transfer, physico-chemical processes, atmospheric aerosol and heterogenous chemistry, anthropic and natural emissions and deposition, stratospheric chemical system, tropospheric chemical system, polluted boundary layer, paleo-environments and ice archives, role of atmospheric chemistry in global changes, measurement principles and instruments, numerical modeling, experimental strategy, regulation and management of the atmospheric environment, index. (J.S.)

  15. Experimental pain leads to reorganisation of trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    The aim of this laboratory study was to investigate acute effects of experimental muscle pain on spatial electromyographic (EMG) activity of the trapezius muscle during computer work with active and passive pauses. Twelve healthy male subjects performed four sessions of computer work for 2 min...... in one day, with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40 s without and with presence of experimental pain. Surface EMG signals were recorded from four parts of the trapezius. The centroid of exposure variation analysis along the time axis...... was lower during computer work with active pauses when compared with passive one in all muscle parts (P

  16. An interactive computer lab of the galvanic cell for students in biochemistry.

    Science.gov (United States)

    Ahlstrand, Emma; Buetti-Dinh, Antoine; Friedman, Ran

    2018-01-01

    We describe an interactive module that can be used to teach basic concepts in electrochemistry and thermodynamics to first year natural science students. The module is used together with an experimental laboratory and improves the students' understanding of thermodynamic quantities such as Δ r G, Δ r H, and Δ r S that are calculated but not directly measured in the lab. We also discuss how new technologies can substitute some parts of experimental chemistry courses, and improve accessibility to course material. Cloud computing platforms such as CoCalc facilitate the distribution of computer codes and allow students to access and apply interactive course tools beyond the course's scope. Despite some limitations imposed by cloud computing, the students appreciated the approach and the enhanced opportunities to discuss study questions with their classmates and instructor as facilitated by the interactive tools. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):58-65, 2018. © 2017 The International Union of Biochemistry and Molecular Biology.

  17. Defined Host-Guest Chemistry on Nanocarbon for Sustained Inhibition of Cancer.

    Science.gov (United States)

    Ostadhossein, Fatemeh; Misra, Santosh K; Mukherjee, Prabuddha; Ostadhossein, Alireza; Daza, Enrique; Tiwari, Saumya; Mittal, Shachi; Gryka, Mark C; Bhargava, Rohit; Pan, Dipanjan

    2016-08-22

    Signal transducer and activator of transcription factor 3 (STAT-3) is known to be overexpressed in cancer stem cells. Poor solubility and variable drug absorption are linked to low bioavailability and decreased efficacy. Many of the drugs regulating STAT-3 expression lack aqueous solubility; hence hindering efficient bioavailability. A theranostics nanoplatform based on luminescent carbon particles decorated with cucurbit[6]uril is introduced for enhancing the solubility of niclosamide, a STAT-3 inhibitor. The host-guest chemistry between cucurbit[6]uril and niclosamide makes the delivery of the hydrophobic drug feasible while carbon nanoparticles enhance cellular internalization. Extensive physicochemical characterizations confirm successful synthesis. Subsequently, the host-guest chemistry of niclosamide and cucurbit[6]uril is studied experimentally and computationally. In vitro assessments in human breast cancer cells indicate approximately twofold enhancement in IC 50 of drug. Fourier transform infrared and fluorescence imaging demonstrate efficient cellular internalization. Furthermore, the catalytic biodegradation of the nanoplatforms occur upon exposure to human myeloperoxidase in short time. In vivo studies on athymic mice with MCF-7 xenograft indicate the size of tumor in the treatment group is half of the controls after 40 d. Immunohistochemistry corroborates the downregulation of STAT-3 phosphorylation. Overall, the host-guest chemistry on nanocarbon acts as a novel arsenal for STAT-3 inhibition. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. On-line chemistry monitoring for the secondary side

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Babcock and Wilcox (B and W) has developed a computerized water chemistry data acquisition and management system for nuclear plant secondary coolant systems. The Integrated Water Chemistry Monitoring System (IWCMS) provides on-line monitoring of conditions and rapid trend analysis of sampled data. So far it has been installed at GPU Three Mile Island unit 1 and at Toledo Edison Davis-Besse. The IWCMS meets the following utility needs for monitoring power plant chemistry: control of chemistry conditions to minimize corrosion and extend component/system life; continuous analysis of data from on-line detectors and grab samples; expediting of transient recovery actions with trend, alarm and evaluation capability; provision for rapid sharing of useful operational chemistry information; concentration of attention on evaluation instead of data manipulation. The system is composed of three functional parts: data acquisition hardware; PC-based computer system and customised system software. (author)

  19. Mutations that Cause Human Disease: A Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Beernink, P; Barsky, D; Pesavento, B

    2006-01-11

    can be used to understand how an amino acid change affects the protein. The experimental methods that provide the most detailed structural information on proteins are X-ray crystallography and NMR spectroscopy. However, these methods are labor intensive and currently cannot be carried out on a genomic scale. Nonetheless, Structural Genomics projects are being pursued by more than a dozen groups and consortia worldwide and as a result the number of experimentally determined structures is rising exponentially. Based on the expectation that protein structures will continue to be determined at an ever-increasing rate, reliable structure prediction schemes will become increasingly valuable, leading to information on protein function and disease for many different proteins. Given known genetic variability and experimentally determined protein structures, can we accurately predict the effects of single amino acid substitutions? An objective assessment of this question would involve comparing predicted and experimentally determined structures, which thus far has not been rigorously performed. The completed research leveraged existing expertise at LLNL in computational and structural biology, as well as significant computing resources, to address this question.

  20. Modelling stratospheric chemistry in a global three-dimensional chemical transport model

    Energy Technology Data Exchange (ETDEWEB)

    Rummukainen, M [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Numerical modelling of atmospheric chemistry aims to increase the understanding of the characteristics, the behavior and the evolution of atmospheric composition. These topics are of utmost importance in the study of climate change. The multitude of gases and particulates making up the atmosphere and the complicated interactions between them affect radiation transfer, atmospheric dynamics, and the impacts of anthropogenic and natural emissions. Chemical processes are fundamental factors in global warming, ozone depletion and atmospheric pollution problems in general. Much of the prevailing work on modelling stratospheric chemistry has so far been done with 1- and 2-dimensional models. Carrying an extensive chemistry parameterisation in a model with high spatial and temporal resolution is computationally heavy. Today, computers are becoming powerful enough to allow going over to 3-dimensional models. In order to concentrate on the chemistry, many Chemical Transport Models (CTM) are still run off-line, i.e. with precalculated and archived meteorology and radiation. In chemistry simulations, the archived values drive the model forward in time, without interacting with the chemical evolution. This is an approach that has been adopted in stratospheric chemistry modelling studies at the Finnish Meteorological Institute. In collaboration with the University of Oslo, a development project was initiated in 1993 to prepare a stratospheric chemistry parameterisation, fit for global 3-dimensional modelling. This article presents the parameterisation approach. Selected results are shown from basic photochemical simulations

  1. Modelling stratospheric chemistry in a global three-dimensional chemical transport model

    Energy Technology Data Exchange (ETDEWEB)

    Rummukainen, M. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1995-12-31

    Numerical modelling of atmospheric chemistry aims to increase the understanding of the characteristics, the behavior and the evolution of atmospheric composition. These topics are of utmost importance in the study of climate change. The multitude of gases and particulates making up the atmosphere and the complicated interactions between them affect radiation transfer, atmospheric dynamics, and the impacts of anthropogenic and natural emissions. Chemical processes are fundamental factors in global warming, ozone depletion and atmospheric pollution problems in general. Much of the prevailing work on modelling stratospheric chemistry has so far been done with 1- and 2-dimensional models. Carrying an extensive chemistry parameterisation in a model with high spatial and temporal resolution is computationally heavy. Today, computers are becoming powerful enough to allow going over to 3-dimensional models. In order to concentrate on the chemistry, many Chemical Transport Models (CTM) are still run off-line, i.e. with precalculated and archived meteorology and radiation. In chemistry simulations, the archived values drive the model forward in time, without interacting with the chemical evolution. This is an approach that has been adopted in stratospheric chemistry modelling studies at the Finnish Meteorological Institute. In collaboration with the University of Oslo, a development project was initiated in 1993 to prepare a stratospheric chemistry parameterisation, fit for global 3-dimensional modelling. This article presents the parameterisation approach. Selected results are shown from basic photochemical simulations

  2. Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Tanghong; Chen, Wei; Cheng, Lei; Bayliss, Ryan D.; Lin, Feng; Plews, Michael R.; Nordlund, Dennis; Doeff, Marca M.; Persson, Kristin A.; Cabana, Jordi (LBNL); (SLAC); (UIC); (UCB)

    2017-02-07

    Reversible intercalation reactions provide the basis for modern battery electrodes. Despite decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials AxK1–xFeF3 (A = Li, Na). By starting with KFeF3, approximately 75% of K+ ions were subsequently replaced by Li+ and Na+ through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopy confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. This study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.

  3. A theoretical and experimental study of neuromorphic atomic switch networks for reservoir computing.

    Science.gov (United States)

    Sillin, Henry O; Aguilera, Renato; Shieh, Hsien-Hang; Avizienis, Audrius V; Aono, Masakazu; Stieg, Adam Z; Gimzewski, James K

    2013-09-27

    Atomic switch networks (ASNs) have been shown to generate network level dynamics that resemble those observed in biological neural networks. To facilitate understanding and control of these behaviors, we developed a numerical model based on the synapse-like properties of individual atomic switches and the random nature of the network wiring. We validated the model against various experimental results highlighting the possibility to functionalize the network plasticity and the differences between an atomic switch in isolation and its behaviors in a network. The effects of changing connectivity density on the nonlinear dynamics were examined as characterized by higher harmonic generation in response to AC inputs. To demonstrate their utility for computation, we subjected the simulated network to training within the framework of reservoir computing and showed initial evidence of the ASN acting as a reservoir which may be optimized for specific tasks by adjusting the input gain. The work presented represents steps in a unified approach to experimentation and theory of complex systems to make ASNs a uniquely scalable platform for neuromorphic computing.

  4. Computer information resources of inorganic chemistry and materials science

    International Nuclear Information System (INIS)

    Kiselyova, N N; Dudarev, V A; Zemskov, V S

    2010-01-01

    Information systems used in inorganic chemistry and materials science are considered. The following basic trends in the development of modern information systems in these areas are highlighted: access to information via the Internet, merging of documental and factual databases, involvement of experts in the evaluation of the data reliability, supplementing databases with information analysis tools on the properties of inorganic substances and materials.

  5. Computer information resources of inorganic chemistry and materials science

    Energy Technology Data Exchange (ETDEWEB)

    Kiselyova, N N; Dudarev, V A; Zemskov, V S [A.A.Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Moscow (Russian Federation)

    2010-02-28

    Information systems used in inorganic chemistry and materials science are considered. The following basic trends in the development of modern information systems in these areas are highlighted: access to information via the Internet, merging of documental and factual databases, involvement of experts in the evaluation of the data reliability, supplementing databases with information analysis tools on the properties of inorganic substances and materials.

  6. Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes Toward Chemistry

    Science.gov (United States)

    Çam, Aylin; Geban, Ömer

    2011-02-01

    The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students' epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes of an urban high school instructed with same teacher. Each teaching method was randomly assigned to one class. The experimental group received case-based learning and the control group received traditional instruction. At the experimental group, life cases were presented with small group format; at the control group, lecturing and discussion was carried out. The results showed that there was a significant difference between the experimental and control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in favor of case-based learning method group. Thus, case base learning is helpful for development of students' epistemological beliefs and attitudes toward chemistry.

  7. Mobilizing EPA's Comptox Chemistry Dashboard Data on Mobile Devices (ACS Spring Meeting)

    Science.gov (United States)

    The EPA’s National Center of Computational Toxicology (NCCT) Chemistry Dashboard provides access to chemistry data for about 720,000 chemical substances. The application is used to source, for example: physicochemical property data, bioassay screening data and functional use, and...

  8. A detailed experimental study of a DNA computer with two endonucleases.

    Science.gov (United States)

    Sakowski, Sebastian; Krasiński, Tadeusz; Sarnik, Joanna; Blasiak, Janusz; Waldmajer, Jacek; Poplawski, Tomasz

    2017-07-14

    Great advances in biotechnology have allowed the construction of a computer from DNA. One of the proposed solutions is a biomolecular finite automaton, a simple two-state DNA computer without memory, which was presented by Ehud Shapiro's group at the Weizmann Institute of Science. The main problem with this computer, in which biomolecules carry out logical operations, is its complexity - increasing the number of states of biomolecular automata. In this study, we constructed (in laboratory conditions) a six-state DNA computer that uses two endonucleases (e.g. AcuI and BbvI) and a ligase. We have presented a detailed experimental verification of its feasibility. We described the effect of the number of states, the length of input data, and the nondeterminism on the computing process. We also tested different automata (with three, four, and six states) running on various accepted input words of different lengths such as ab, aab, aaab, ababa, and of an unaccepted word ba. Moreover, this article presents the reaction optimization and the methods of eliminating certain biochemical problems occurring in the implementation of a biomolecular DNA automaton based on two endonucleases.

  9. Primary water chemistry monitoring from the point of view of radiation build-up

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, G L [Institute for Electrical Power Research, Budapest (Hungary); Civin, V [Hungarian Electricity Generating Board, Budapest (Hungary); Pinter, T [Nuclear Power Plant PAKS, Budapest (Hungary)

    1997-02-01

    Basic operational principles of a computer code system calculating the primary circuit corrosion product activities based on actual measured plant chemistry data are presented. The code system consists of two parts: FeSolub.prg: calculates the characteristic iron solubilities based on actual primary water chemistry (H{sub 3}BO{sub 3}KOH, ... etc.) and plant load (MW) data. A developed solubility calculation method has been applied fitted to magnetite solubility data of several authors; RADTRAN.exe: calculates primary circuit water and surface corrosion product activities based on results of FeSolub.prg or planned water chemistry data up to the next shutdown. The computer code system is going to be integrated into a general primary water chemistry monitoring and surveillance system. (author). 15 refs, 4 figs, 3 tabs.

  10. Using quantum chemistry muscle to flex massive systems: How to respond to something perturbing

    Energy Technology Data Exchange (ETDEWEB)

    Bertoni, Colleen [Iowa State Univ., Ames, IA (United States)

    2016-12-17

    Computational chemistry uses the theoretical advances of quantum mechanics and the algorithmic and hardware advances of computer science to give insight into chemical problems. It is currently possible to do highly accurate quantum chemistry calculations, but the most accurate methods are very computationally expensive. Thus it is only feasible to do highly accurate calculations on small molecules, since typically more computationally efficient methods are also less accurate. The overall goal of my dissertation work has been to try to decrease the computational expense of calculations without decreasing the accuracy. In particular, my dissertation work focuses on fragmentation methods, intermolecular interactions methods, analytic gradients, and taking advantage of new hardware.

  11. Towards quantum chemistry on a quantum computer.

    Science.gov (United States)

    Lanyon, B P; Whitfield, J D; Gillett, G G; Goggin, M E; Almeida, M P; Kassal, I; Biamonte, J D; Mohseni, M; Powell, B J; Barbieri, M; Aspuru-Guzik, A; White, A G

    2010-02-01

    Exact first-principles calculations of molecular properties are currently intractable because their computational cost grows exponentially with both the number of atoms and basis set size. A solution is to move to a radically different model of computing by building a quantum computer, which is a device that uses quantum systems themselves to store and process data. Here we report the application of the latest photonic quantum computer technology to calculate properties of the smallest molecular system: the hydrogen molecule in a minimal basis. We calculate the complete energy spectrum to 20 bits of precision and discuss how the technique can be expanded to solve large-scale chemical problems that lie beyond the reach of modern supercomputers. These results represent an early practical step toward a powerful tool with a broad range of quantum-chemical applications.

  12. Problem-based learning on quantitative analytical chemistry course

    Science.gov (United States)

    Fitri, Noor

    2017-12-01

    This research applies problem-based learning method on chemical quantitative analytical chemistry, so called as "Analytical Chemistry II" course, especially related to essential oil analysis. The learning outcomes of this course include aspects of understanding of lectures, the skills of applying course materials, and the ability to identify, formulate and solve chemical analysis problems. The role of study groups is quite important in improving students' learning ability and in completing independent tasks and group tasks. Thus, students are not only aware of the basic concepts of Analytical Chemistry II, but also able to understand and apply analytical concepts that have been studied to solve given analytical chemistry problems, and have the attitude and ability to work together to solve the problems. Based on the learning outcome, it can be concluded that the problem-based learning method in Analytical Chemistry II course has been proven to improve students' knowledge, skill, ability and attitude. Students are not only skilled at solving problems in analytical chemistry especially in essential oil analysis in accordance with local genius of Chemistry Department, Universitas Islam Indonesia, but also have skilled work with computer program and able to understand material and problem in English.

  13. Evaluation of computer-based learning material for food chemistry education

    NARCIS (Netherlands)

    Diederen, J.; Gruppen, H.; Hartog, R.J.M.; Voragen, A.G.J.

    2005-01-01

    Digital exercises were designed and developed for food chemistry education. During the design process, design requirements were described for such exercises. The exercises were evaluated in three case studies, firstly to determine whether the exercises satisfy the design requirements with respect to

  14. Computations for the 1:5 model of the THTR pressure vessel compared with experimental results

    International Nuclear Information System (INIS)

    Stangenberg, F.

    1972-01-01

    In this report experimental results measured at the 1:5-model of the prestressed concrete pressure vessel of the THTR-nuclear power station Schmehausen in 1971, are compared with the results of axis-symmetrical computations. Linear-elastic computations were performed as well as approximate computations for overload pressures taking into consideration the influences of the load history (prestressing, temperature, creep) and the effects of the steel components. (orig.) [de

  15. EXPERIMENTAL VERIFICATION OF COMPUTER MODEL OF COOLING SYSTEM FOR POWERFUL SEMI- CONDUCTOR DEVICE

    Directory of Open Access Journals (Sweden)

    I. A. Khorunzhii

    2007-01-01

    Full Text Available A cooling system for powerful semi-conductor device (power -1 kW consisting of a pin-type radiator and a body is considered in the paper. Cooling is carried out by forced convection of a coolant. Calculated values of temperatures on the radiator surface and experimentally measured values of temperatures in the same surface points have been compared in the paper. It has been shown that the difference between calculated and experimentally measured temperatures does not exceed 0,1-0,2 °C and it is comparable with experimental error value. The given results confirm correctness of a computer model.

  16. Some observations on hydrazine and ammonia based chemistries in PWRs

    International Nuclear Information System (INIS)

    Brunning, J.; Cake, P.; Harper, A.; Sims, H.E.

    1997-01-01

    This paper presents a comparison of factors related to activated corrosion product transport in pressurized water reactors (PWRs) operating hydrazine and ammonia-based chemistries. Measurements of the concentrations of corrosion products in the coolant of reactors operating both chemistry regimes are compared under steady operation and during shutdown. These data allow some comparisons to be drawn of corrosion product transport under ammonia and hydrazine based chemistries. Experimental measurements of electrochemical potential under PWR conditions in the presence and absence of radiation fields and under hydrazine and ammonia chemistries are also presented. (author). 4 refs, 5 figs, 2 tabs

  17. Some observations on hydrazine and ammonia based chemistries in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Brunning, J; Cake, P; Harper, A; Sims, H E [AEA Technology, Oxon (United Kingdom)

    1997-02-01

    This paper presents a comparison of factors related to activated corrosion product transport in pressurized water reactors (PWRs) operating hydrazine and ammonia-based chemistries. Measurements of the concentrations of corrosion products in the coolant of reactors operating both chemistry regimes are compared under steady operation and during shutdown. These data allow some comparisons to be drawn of corrosion product transport under ammonia and hydrazine based chemistries. Experimental measurements of electrochemical potential under PWR conditions in the presence and absence of radiation fields and under hydrazine and ammonia chemistries are also presented. (author). 4 refs, 5 figs, 2 tabs.

  18. EXPERIMENTAL AND COMPUTATIONAL STUDIES OF THE FORMATION MECHANISM OF PROTONATED INTERSTELLAR DIAZINES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe-Chen; Cole, Callie A.; Bierbaum, Veronica M. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309 (United States); Snow, Theodore P., E-mail: zhwa4666@colorado.edu [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2015-01-10

    Studies of interstellar chemistry have grown in number and complexity by both observations and laboratory measurements, and nitrogen-containing aromatics have been implicated as important interstellar molecules. In this paper, the gas-phase collision induced dissociation (CID) processes of protonated pyridazine (1,2-diazine), pyrimidine (1,3-diazine), and pyrazine (1,4-diazine) cations (C{sub 4}H{sub 5}N{sub 2} {sup +}) are investigated in detail both experimentally and theoretically. The major neutral loss for all three CID processes is HCN, leading to the formation of C{sub 3}H{sub 4}N{sup +} isomers; our density functional theory (DFT) calculations support and elucidate our experimental results. The formation of C{sub 3}H{sub 4}N{sup +} isomers from the reaction of abundant interstellar acrylonitrile (CH{sub 2}CHCN) and H{sup +}is also studied employing DFT calculations. Our results lead to a novel mechanism for interstellar protonated diazine formation from the consecutive reactions of CH{sub 2}CHCN+ H{sup +} + HCN. Moreover, our results motivate the continuing search for interstellar C{sub 3}H{sub 4}N{sup +} isomers as well as polycyclic aromatic N-containing hydrocarbons (PANHs)

  19. Synthesis meets theory: Past, present and future of rational chemistry

    Science.gov (United States)

    Fianchini, Mauro

    2017-11-01

    Chemical synthesis has its roots in the empirical approach of alchemy. Nonetheless, the birth of the scientific method, the technical and technological advances (exploiting revolutionary discoveries in physics) and the improved management and sharing of growing databases greatly contributed to the evolution of chemistry from an esoteric ground into a mature scientific discipline during these last 400 years. Furthermore, thanks to the evolution of computational resources, platforms and media in the last 40 years, theoretical chemistry has added to the puzzle the final missing tile in the process of "rationalizing" chemistry. The use of mathematical models of chemical properties, behaviors and reactivities is nowadays ubiquitous in literature. Theoretical chemistry has been successful in the difficult task of complementing and explaining synthetic results and providing rigorous insights when these are otherwise unattainable by experiment. The first part of this review walks the reader through a concise historical overview on the evolution of the "model" in chemistry. Salient milestones have been highlighted and briefly discussed. The second part focuses more on the general description of recent state-of-the-art computational techniques currently used worldwide by chemists to produce synergistic models between theory and experiment. Each section is complemented by key-examples taken from the literature that illustrate the application of the technique discussed therein.

  20. Experimental and computer thermodynamics evaluations of an Al-Si-Coating on a quenchable steel

    International Nuclear Information System (INIS)

    Trindade, Vicente Braz

    2017-01-01

    High-strength steels are commonly used in the automobile industry in order to reduce the weight of the vehicles. However, a technical difficulty appears due to the need of hot stamping of the components, which leads to oxidation. Therefore, the application of a coating on the substrate to avoid high-temperature oxidation is used. In this work, experimental analysis and computer thermodynamic calculation were used to describe the phase transformations within an Al-Si coating on a quenchable high strength steel. The Al-Si coating was deposited by hot dipping and its characterization was done using SEM and XRD techniques. Computer thermodynamics calculations were done using the commercial software FactSage using the Calphad methodology. It demonstrated a good relationship between the experimental results and the computer calculations of phase stabilities for the as-deposited condition and after diffusion experiment at 920 deg C for 7 minutes, which simulates the thermal cycle of hot stamping of the quenchable steel used. (author)

  1. Experimental and computer thermodynamics evaluations of an Al-Si-Coating on a quenchable steel

    Energy Technology Data Exchange (ETDEWEB)

    Trindade, Vicente Braz, E-mail: vicentebraz@yahoo.com.b [Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG (Brazil). Escola de Minas. Departamento de Engenharia Metalurgica e de Materiais; Christ, Hans-Juergen, E-mail: christ@ifwt.mb.uni-siegen.de [University of Siegen (Germany)

    2017-01-15

    High-strength steels are commonly used in the automobile industry in order to reduce the weight of the vehicles. However, a technical difficulty appears due to the need of hot stamping of the components, which leads to oxidation. Therefore, the application of a coating on the substrate to avoid high-temperature oxidation is used. In this work, experimental analysis and computer thermodynamic calculation were used to describe the phase transformations within an Al-Si coating on a quenchable high strength steel. The Al-Si coating was deposited by hot dipping and its characterization was done using SEM and XRD techniques. Computer thermodynamics calculations were done using the commercial software FactSage using the Calphad methodology. It demonstrated a good relationship between the experimental results and the computer calculations of phase stabilities for the as-deposited condition and after diffusion experiment at 920 deg C for 7 minutes, which simulates the thermal cycle of hot stamping of the quenchable steel used. (author)

  2. Proceedings of DAE-BRNS third international symposium on materials chemistry

    International Nuclear Information System (INIS)

    Tyagi, Deepak; Banerjee, Atindra Mohan; Nigam, Sandeep; Varma, Salil; Tripathi, Arvind Kumar; Bharadwaj, Shyamala Rajkumar; Das, Dasarathi

    2010-12-01

    The present volume consists of the proceedings of the DAE-BRNS Third International Symposium on Materials Chemistry. In order to keep pace with the advancements made in the area of materials chemistry, new topics like materials for energy conversion, biomaterials, carbon based materials, soft condensed materials, thin films, surface chemistry, polymer based materials, organic and organometallics, magnetic materials and high purity materials have been included in this symposium while topics like nuclear materials, nanomaterials and clusters, catalysis, chemical sensors, fuel cell materials and computational research in materials chemistry have been continued as important features of the symposium. Papers relevant to INIS are indexed separately

  3. Practical experimental certification of computational quantum gates using a twirling procedure.

    Science.gov (United States)

    Moussa, Osama; da Silva, Marcus P; Ryan, Colm A; Laflamme, Raymond

    2012-08-17

    Because of the technical difficulty of building large quantum computers, it is important to be able to estimate how faithful a given implementation is to an ideal quantum computer. The common approach of completely characterizing the computation process via quantum process tomography requires an exponential amount of resources, and thus is not practical even for relatively small devices. We solve this problem by demonstrating that twirling experiments previously used to characterize the average fidelity of quantum memories efficiently can be easily adapted to estimate the average fidelity of the experimental implementation of important quantum computation processes, such as unitaries in the Clifford group, in a practical and efficient manner with applicability in current quantum devices. Using this procedure, we demonstrate state-of-the-art coherent control of an ensemble of magnetic moments of nuclear spins in a single crystal solid by implementing the encoding operation for a 3-qubit code with only a 1% degradation in average fidelity discounting preparation and measurement errors. We also highlight one of the advances that was instrumental in achieving such high fidelity control.

  4. Parallel computing in experimental mechanics and optical measurement: A review (II)

    Science.gov (United States)

    Wang, Tianyi; Kemao, Qian

    2018-05-01

    With advantages such as non-destructiveness, high sensitivity and high accuracy, optical techniques have successfully integrated into various important physical quantities in experimental mechanics (EM) and optical measurement (OM). However, in pursuit of higher image resolutions for higher accuracy, the computation burden of optical techniques has become much heavier. Therefore, in recent years, heterogeneous platforms composing of hardware such as CPUs and GPUs, have been widely employed to accelerate these techniques due to their cost-effectiveness, short development cycle, easy portability, and high scalability. In this paper, we analyze various works by first illustrating their different architectures, followed by introducing their various parallel patterns for high speed computation. Next, we review the effects of CPU and GPU parallel computing specifically in EM & OM applications in a broad scope, which include digital image/volume correlation, fringe pattern analysis, tomography, hyperspectral imaging, computer-generated holograms, and integral imaging. In our survey, we have found that high parallelism can always be exploited in such applications for the development of high-performance systems.

  5. The Application of Computational Chemistry to Problems in Mass Spectrometry

    Science.gov (United States)

    Quantum chemistry is capable of calculating a wide range of electronic and thermodynamic properties of interest to a chemist or physicist. Calculations can be used both to predict the results of future experiments and to aid in the interpretation of existing results. This paper w...

  6. Upwind MacCormack Euler solver with non-equilibrium chemistry

    Science.gov (United States)

    Sherer, Scott E.; Scott, James N.

    1993-01-01

    A computer code, designated UMPIRE, is currently under development to solve the Euler equations in two dimensions with non-equilibrium chemistry. UMPIRE employs an explicit MacCormack algorithm with dissipation introduced via Roe's flux-difference split upwind method. The code also has the capability to employ a point-implicit methodology for flows where stiffness is introduced through the chemical source term. A technique consisting of diagonal sweeps across the computational domain from each corner is presented, which is used to reduce storage and execution requirements. Results depicting one dimensional shock tube flow for both calorically perfect gas and thermally perfect, dissociating nitrogen are presented to verify current capabilities of the program. Also, computational results from a chemical reactor vessel with no fluid dynamic effects are presented to check the chemistry capability and to verify the point implicit strategy.

  7. Combined computational and experimental approach to improve the assessment of mitral regurgitation by echocardiography.

    Science.gov (United States)

    Sonntag, Simon J; Li, Wei; Becker, Michael; Kaestner, Wiebke; Büsen, Martin R; Marx, Nikolaus; Merhof, Dorit; Steinseifer, Ulrich

    2014-05-01

    Mitral regurgitation (MR) is one of the most frequent valvular heart diseases. To assess MR severity, color Doppler imaging (CDI) is the clinical standard. However, inadequate reliability, poor reproducibility and heavy user-dependence are known limitations. A novel approach combining computational and experimental methods is currently under development aiming to improve the quantification. A flow chamber for a circulatory flow loop was developed. Three different orifices were used to mimic variations of MR. The flow field was recorded simultaneously by a 2D Doppler ultrasound transducer and Particle Image Velocimetry (PIV). Computational Fluid Dynamics (CFD) simulations were conducted using the same geometry and boundary conditions. The resulting computed velocity field was used to simulate synthetic Doppler signals. Comparison between PIV and CFD shows a high level of agreement. The simulated CDI exhibits the same characteristics as the recorded color Doppler images. The feasibility of the proposed combination of experimental and computational methods for the investigation of MR is shown and the numerical methods are successfully validated against the experiments. Furthermore, it is discussed how the approach can be used in the long run as a platform to improve the assessment of MR quantification.

  8. Thermodynamic properties of 1-naphthol: Mutual validation of experimental and computational results

    International Nuclear Information System (INIS)

    Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.

    2015-01-01

    Highlights: • Heat capacities were measured for the temperature range 5 K to 445 K. • Vapor pressures were measured for the temperature range 370 K to 570 K. • Computed and derived properties for ideal gas entropies are in excellent accord. • The enthalpy of combustion was measured and shown to be consistent with reliable literature values. • Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Thermodynamic properties for 1-naphthol (Chemical Abstracts registry number [90-15-3]) in the ideal-gas state are reported based on both experimental and computational methods. Measured properties included the triple-point temperature, enthalpy of fusion, and heat capacities for the crystal and liquid phases by adiabatic calorimetry; vapor pressures by inclined-piston manometry and comparative ebulliometry; and the enthalpy of combustion of the crystal phase by oxygen bomb calorimetry. Critical properties were estimated. Entropies for the ideal-gas state were derived from the experimental studies for the temperature range 298.15 ⩽ T/K ⩽ 600, and independent statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. The mutual validation of the independent experimental and computed results is achieved with a scaling factor of 0.975 applied to the calculated vibrational frequencies. This same scaling factor was successfully applied in the analysis of results for other polycyclic molecules, as described in a series of recent articles by this research group. This article reports the first extension of this approach to a hydroxy-aromatic compound. All experimental results are compared with property values reported in the literature. Thermodynamic consistency between properties is used to show that several studies in the literature are erroneous. The enthalpy of combustion for 1-naphthol was also measured in this research, and excellent

  9. COMPUTATIONAL SCIENCE CENTER

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT,J.

    2004-11-01

    The Brookhaven Computational Science Center brings together researchers in biology, chemistry, physics, and medicine with applied mathematicians and computer scientists to exploit the remarkable opportunities for scientific discovery which have been enabled by modern computers. These opportunities are especially great in computational biology and nanoscience, but extend throughout science and technology and include for example, nuclear and high energy physics, astrophysics, materials and chemical science, sustainable energy, environment, and homeland security.

  10. A comprehensive combined experimental and computational framework for pre-clinical wear simulation of total knee replacements.

    Science.gov (United States)

    Abdelgaied, A; Fisher, J; Jennings, L M

    2018-02-01

    A more robust pre-clinical wear simulation framework is required in order to simulate wider and higher ranges of activities, observed in different patient populations such as younger more active patients. Such a framework will help to understand and address the reported higher failure rates for younger and more active patients (National_Joint_Registry, 2016). The current study has developed and validated a comprehensive combined experimental and computational framework for pre-clinical wear simulation of total knee replacements (TKR). The input mechanical (elastic modulus and Poisson's ratio) and wear parameters of the moderately cross-linked ultra-high molecular weight polyethylene (UHMWPE) bearing material were independently measured from experimental studies under realistic test conditions, similar to the loading conditions found in the total knee replacements. The wear predictions from the computational wear simulation were validated against the direct experimental wear measurements for size 3 Sigma curved total knee replacements (DePuy, UK) in an independent experimental wear simulation study under three different daily activities; walking, deep squat, and stairs ascending kinematic conditions. The measured compressive mechanical properties of the moderately cross-linked UHMWPE material were more than 20% lower than that reported in the literature under tensile test conditions. The pin-on-plate wear coefficient of moderately cross-linked UHMWPE was significantly dependant of the contact stress and the degree of cross-shear at the articulating surfaces. The computational wear predictions for the TKR from the current framework were consistent and in a good agreement with the independent full TKR experimental wear simulation measurements, with 0.94 coefficient of determination of the framework. In addition, the comprehensive combined experimental and computational framework was able to explain the complex experimental wear trends from the three different daily

  11. Quantum-Enhanced Cyber Security: Experimental Computation on Quantum-Encrypted Data

    Science.gov (United States)

    2017-03-02

    AFRL-AFOSR-UK-TR-2017-0020 Quantum-Enhanced Cyber Security: Experimental Computation on Quantum- Encrypted Data Philip Walther UNIVERSITT WIEN Final...on Quantum- Encrypted Data 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-16-1-0004 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Philip Walther 5d...1010 AT 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) EOARD Unit 4515 APO AE 09421-4515 10

  12. Fundamental atomic plasma chemistry for semiconductor manufacturing process analysis

    International Nuclear Information System (INIS)

    Ventzek, P.L.G.; Zhang, D.; Stout, P.J.; Rauf, S.; Orlowski, M.; Kudrya, V.; Astapenko, V.; Eletskii, A.

    2002-01-01

    An absence of fundamental atomic plasma chemistry data (e.g. electron impact cross-sections) hinders the application of plasma process models in semiconductor manufacturing. Of particular importance is excited state plasma chemistry data for metallization applications. This paper describes important plasma chemistry processes in the context of high density plasmas for metallization application and methods for the calculation of data for the study of these processes. Also discussed is the development of model data sets that address computational tractability issues. Examples of model electron impact cross-sections for Ni reduced from multiple collision processes are presented

  13. The effectiveness of computer-generated 3D animations in inquiry chemistry laboratory

    Science.gov (United States)

    Theall, Rachel Morgan

    It has been shown that students need a molecular-level understanding of substances in order to comprehend chemistry. For solid structures, atomic-level understanding requires students to learn additional and different concepts than for other states of matter. To aid understanding, animations were created to model unit cell structures and depict the properties of unit cells. In order to determine if these animations are helpful to students, they were tested during a laboratory exercise in which students had previously been using model kits and images from textbooks to learn about solid structures. Students evaluated in this study were from two lecture sections of general chemistry, one that routinely used animations during lecture and one that used a more traditional lecture format that did not include animations or models. Twelve laboratory sections of these lectures, taught by six different instructors each teaching two sections, were chosen for participation. One section for each instructor was given the animations as an optional tool for completing the laboratory assignment, which consisted of questions about unit cells and crystal structures. The results of the study indicate that students who looked at the animations performed significantly better on the assignment. For the control group, students who routinely viewed multiple representations of chemistry in lecture performed significantly better on the lab assignment than students in the lecture section where chemistry concepts were only presented on the chalkboard and overhead projector. Students in the traditional lecture section also had significantly less appreciation for the model kits used in the laboratory than students in the other lecture section. Observations of students in the lab combined with statistical results led to the revision of the solid structures investigation. Additional animations were created and inserted into the module that covered areas where students indicated more help was needed

  14. Chemistry of superheavy elements

    International Nuclear Information System (INIS)

    Schaedel, M.

    2012-01-01

    The chemistry of superheavy elements - or transactinides from their position in the Periodic Table - is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ('pre-separator') are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table. (orig.)

  15. Computational and experimental optimization of the exhaust air energy recovery wind turbine generator

    International Nuclear Information System (INIS)

    Tabatabaeikia, Seyedsaeed; Ghazali, Nik Nazri Bin Nik; Chong, Wen Tong; Shahizare, Behzad; Izadyar, Nima; Esmaeilzadeh, Alireza; Fazlizan, Ahmad

    2016-01-01

    Highlights: • Studying the viability of harvesting wasted energy by exhaust air recovery generator. • Optimizing the design using response surface methodology. • Validation of optimization and computation result by performing experimental tests. • Investigation of flow behaviour using computational fluid dynamic simulations. • Performing the technical and economic study of the exhaust air recovery generator. - Abstract: This paper studies the optimization of an innovative exhaust air recovery wind turbine generator through computational fluid dynamic (CFD) simulations. The optimization strategy aims to optimize the overall system energy generation and simultaneously guarantee that it does not violate the cooling tower performance in terms of decreasing airflow intake and increasing fan motor power consumption. The wind turbine rotor position, modifying diffuser plates, and introducing separator plates to the design are considered as the variable factors for the optimization. The generated power coefficient is selected as optimization objective. Unlike most of previous optimizations in field of wind turbines, in this study, response surface methodology (RSM) as a method of analytical procedures optimization has been utilised by using multivariate statistic techniques. A comprehensive study on CFD parameters including the mesh resolution, the turbulence model and transient time step values is presented. The system is simulated using SST K-ω turbulence model and then both computational and optimization results are validated by experimental data obtained in laboratory. Results show that the optimization strategy can improve the wind turbine generated power by 48.6% compared to baseline design. Meanwhile, it is able to enhance the fan intake airflow rate and decrease fan motor power consumption. The obtained optimization equations are also validated by both CFD and experimental results and a negligible deviation in range of 6–8.5% is observed.

  16. Cyclopentane combustion chemistry. Part I: Mechanism development and computational kinetics

    KAUST Repository

    Rachidi, Mariam El

    2017-06-23

    Cycloalkanes are significant constituents of conventional fossil fuels, in which they are one of the main contributors to soot formation, but also significantly influence the ignition characteristics below ∼900K. This paper discusses the development of a detailed high- and low-temperature oxidation mechanism for cyclopentane, which is an important archetypical cycloalkane. The differences between cyclic and non-cyclic alkane chemistry, and thus the inapplicability of acyclic alkane analogies, required the detailed theoretical investigation of the kinetics of important cyclopentane oxidation reactions as part of the mechanism development. The cyclopentyl+O reaction was investigated at the UCCSD(T)-F12a/cc-pVTZ-F12//M06-2X/6-311++G(d,p) level of theory in a time-dependent master equation framework. Comparisons with analogous cyclohexane or non-cyclic alkane reactions are presented. Our study suggests that beyond accurate quantum chemistry the inclusion of pressure dependence and especially that of formally direct kinetics is crucial even at pressures relevant for practical application.

  17. Cyclopentane combustion chemistry. Part I: Mechanism development and computational kinetics

    KAUST Repository

    Rachidi, Mariam El; Mehl, Marco; Pitz, William J.; Mohamed, Samah; Sarathy, Mani

    2017-01-01

    Cycloalkanes are significant constituents of conventional fossil fuels, in which they are one of the main contributors to soot formation, but also significantly influence the ignition characteristics below ∼900K. This paper discusses the development of a detailed high- and low-temperature oxidation mechanism for cyclopentane, which is an important archetypical cycloalkane. The differences between cyclic and non-cyclic alkane chemistry, and thus the inapplicability of acyclic alkane analogies, required the detailed theoretical investigation of the kinetics of important cyclopentane oxidation reactions as part of the mechanism development. The cyclopentyl+O reaction was investigated at the UCCSD(T)-F12a/cc-pVTZ-F12//M06-2X/6-311++G(d,p) level of theory in a time-dependent master equation framework. Comparisons with analogous cyclohexane or non-cyclic alkane reactions are presented. Our study suggests that beyond accurate quantum chemistry the inclusion of pressure dependence and especially that of formally direct kinetics is crucial even at pressures relevant for practical application.

  18. Simultaneous assessment of phase chemistry, phase abundance and bulk chemistry with statistical electron probe micro-analyses: Application to cement clinkers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, William; Krakowiak, Konrad J.; Ulm, Franz-Josef, E-mail: ulm@mit.edu

    2014-01-15

    According to recent developments in cement clinker engineering, the optimization of chemical substitutions in the main clinker phases offers a promising approach to improve both reactivity and grindability of clinkers. Thus, monitoring the chemistry of the phases may become part of the quality control at the cement plants, along with the usual measurements of the abundance of the mineralogical phases (quantitative X-ray diffraction) and the bulk chemistry (X-ray fluorescence). This paper presents a new method to assess these three complementary quantities with a single experiment. The method is based on electron microprobe spot analyses, performed over a grid located on a representative surface of the sample and interpreted with advanced statistical tools. This paper describes the method and the experimental program performed on industrial clinkers to establish the accuracy in comparison to conventional methods. -- Highlights: •A new method of clinker characterization •Combination of electron probe technique with cluster analysis •Simultaneous assessment of phase abundance, composition and bulk chemistryExperimental validation performed on industrial clinkers.

  19. Simultaneous assessment of phase chemistry, phase abundance and bulk chemistry with statistical electron probe micro-analyses: Application to cement clinkers

    International Nuclear Information System (INIS)

    Wilson, William; Krakowiak, Konrad J.; Ulm, Franz-Josef

    2014-01-01

    According to recent developments in cement clinker engineering, the optimization of chemical substitutions in the main clinker phases offers a promising approach to improve both reactivity and grindability of clinkers. Thus, monitoring the chemistry of the phases may become part of the quality control at the cement plants, along with the usual measurements of the abundance of the mineralogical phases (quantitative X-ray diffraction) and the bulk chemistry (X-ray fluorescence). This paper presents a new method to assess these three complementary quantities with a single experiment. The method is based on electron microprobe spot analyses, performed over a grid located on a representative surface of the sample and interpreted with advanced statistical tools. This paper describes the method and the experimental program performed on industrial clinkers to establish the accuracy in comparison to conventional methods. -- Highlights: •A new method of clinker characterization •Combination of electron probe technique with cluster analysis •Simultaneous assessment of phase abundance, composition and bulk chemistryExperimental validation performed on industrial clinkers

  20. Medicinal chemistry for 2020

    Science.gov (United States)

    Satyanarayanajois, Seetharama D; Hill, Ronald A

    2011-01-01

    Rapid advances in our collective understanding of biomolecular structure and, in concert, of biochemical systems, coupled with developments in computational methods, have massively impacted the field of medicinal chemistry over the past two decades, with even greater changes appearing on the horizon. In this perspective, we endeavor to profile some of the most prominent determinants of change and speculate as to further evolution that may consequently occur during the next decade. The five main angles to be addressed are: protein–protein interactions; peptides and peptidomimetics; molecular diversity and pharmacological space; molecular pharmacodynamics (significance, potential and challenges); and early-stage clinical efficacy and safety. We then consider, in light of these, the future of medicinal chemistry and the educational preparation that will be required for future medicinal chemists. PMID:22004084

  1. Maximizing the Adjacent Possible in Automata Chemistries.

    Science.gov (United States)

    Hickinbotham, Simon; Clark, Edward; Nellis, Adam; Stepney, Susan; Clarke, Tim; Young, Peter

    2016-01-01

    Automata chemistries are good vehicles for experimentation in open-ended evolution, but they are by necessity complex systems whose low-level properties require careful design. To aid the process of designing automata chemistries, we develop an abstract model that classifies the features of a chemistry from a physical (bottom up) perspective and from a biological (top down) perspective. There are two levels: things that can evolve, and things that cannot. We equate the evolving level with biology and the non-evolving level with physics. We design our initial organisms in the biology, so they can evolve. We design the physics to facilitate evolvable biologies. This architecture leads to a set of design principles that should be observed when creating an instantiation of the architecture. These principles are Everything Evolves, Everything's Soft, and Everything Dies. To evaluate these ideas, we present experiments in the recently developed Stringmol automata chemistry. We examine the properties of Stringmol with respect to the principles, and so demonstrate the usefulness of the principles in designing automata chemistries.

  2. High pressure in solid state chemistry: Combined experimental and modeling approaches for assessing and predicting properties

    Science.gov (United States)

    Etourneau, Jean; Matar, Samir F.

    2018-06-01

    The thermodynamic pressure parameter has been thoroughly used with mastership by Gérard Demazeau throughout his rich career in solid state chemistry and materials sciences and more recently in biosciences. After a review of such works, focus is made in this topical article on his contribution together with his team in the field of hard materials based on light elements B, C, N with a proposition of a new ultra-hard carbon nitride C2N on one hand and on the structural transformations under high pressures of perovskite into postperovskite with a change of dimensionality from 3D to 2D and related oxides, regarding the arrangement of octahedra, on the other hand. Investigation and concepts first arising from experimental observables are shown to be aided and accelerated via first principles calculations of energy and energy-related quantities.

  3. Monitoring and control system for tuneable high frequency microwave assisted chemistry

    International Nuclear Information System (INIS)

    Lewis, G P; Wylie, S R; Shaw, A; Al-Shamma'a, A I; Phipps, D; Alkhaddar, R; Bond, G

    2007-01-01

    Microwave chemistry is an established technique in the synthesis of organic compounds at a frequency of 2.45 GHz. This is considered to be a result of the development of microwave ovens, rather than an objective solution, which maximises efficiency through careful selection of the operating frequency. To obtain a frequency for a dielectric, the complex permittivity should be determined as a function of frequency. If the correct heating frequency is found, superheating can occur when a liquid solvent reaches its boiling point and exceeds it. This paper presents sensor diodes and temperature sensors used in a mono-mode reactor, with computer control of an E-H tuner, frequency and incident power to control temperature and power, experimental results showing heating and reactions using ethanol are reported

  4. "Named Small but Doing Great": An Investigation of Small-Scale Chemistry Experimentation for Effective Undergraduate Practical Work

    Science.gov (United States)

    Tesfamariam, Gebrekidan Mebrahtu; Lykknes, Annette; Kvittingen, Lise

    2017-01-01

    In theory, practical work is an established part of university-level chemistry courses. However, mainly due to budget constraints, large class size, time constraints and inadequate teacher preparations, practical activities are frequently left out from chemistry classroom instruction in most developing countries. Small-scale chemistry (SSC)…

  5. WWER water chemistry related to fuel cladding behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Kysela, J; Zmitko, M [Nuclear Research Inst. plc., Rez (Czech Republic); Vrtilkova, V [Nuclear Fuel Inst., Prague (Czech Republic)

    1997-02-01

    Operational experience in WWER primary water chemistry and corrosion related to the fuel cladding is reviewed. Insignificant corrosion of fuel cladding was found which is caused by good corrosion resistance of Zr1Nb material and relatively low coolant temperature at WWER-440 reactor units. The differences in water chemistry control is outlined and an attention to the question of compatibility of Zircaloys with WWER water chemistry is given. Some results of research and development in field of zirconium alloy corrosion behaviour are discussed. Experimental facility for in-pile and out-of-pile cladding material corrosion testing is shown. (author). 14 refs, 5 figs, 3 tabs.

  6. Calculating buoy response for a wave energy converter—A comparison of two computational methods and experimental results

    Directory of Open Access Journals (Sweden)

    Linnea Sjökvist

    2017-05-01

    Full Text Available When designing a wave power plant, reliable and fast simulation tools are required. Computational fluid dynamics (CFD software provides high accuracy but with a very high computational cost, and in operational, moderate sea states, linear potential flow theories may be sufficient to model the hydrodynamics. In this paper, a model is built in COMSOL Multiphysics to solve for the hydrodynamic parameters of a point-absorbing wave energy device. The results are compared with a linear model where the hydrodynamical parameters are computed using WAMIT, and to experimental results from the Lysekil research site. The agreement with experimental data is good for both numerical models.

  7. Plutonium chemistry: a synthesis of experimental data and a quantitative model for plutonium oxide solubility

    International Nuclear Information System (INIS)

    Haschke, J.M.; Oversby, V.M.

    2002-01-01

    The chemistry of plutonium is important for assessing potential behavior of radioactive waste under conditions of geologic disposal. This paper reviews experimental data on dissolution of plutonium oxide solids, describes a hybrid kinetic-equilibrium model for predicting steady-state Pu concentrations, and compares laboratory results with predicted Pu concentrations and oxidation-state distributions. The model is based on oxidation of PuO 2 by water to produce PuO 2+x , an oxide that can release Pu(V) to solution. Kinetic relationships between formation of PuO 2+x , dissolution of Pu(V), disproportionation of Pu(V) to Pu(IV) and Pu(VI), and reduction of Pu(VI) are given and used in model calculations. Data from tests of pyrochemical salt wastes in brines are discussed and interpreted using the conceptual model. Essential data for quantitative modeling at conditions relevant to nuclear waste repositories are identified and laboratory experiments to determine rate constants for use in the model are discussed

  8. Actinide chemistry in the far field

    International Nuclear Information System (INIS)

    Livens, F.R.; Morris, K.; Parkman, R.; Moyes, L.

    1996-01-01

    The environmental chemistry of the actinides is complicated due both to the extensive redox and coordination chemistry of the elements and also to the complexity of the reactive phases encountered in natural environments. In the far field, interactions with reactive surfaces, coatings and colloidal particles will play a crucial role in controlling actinide mobility. By virtue of both their abundance and reactivity; clays and other layer aluminosilicate minerals, hydrous oxides and organic matter (humic substances) are all identified as having the potential to react with actinide ions and some possible modes of interaction are described, together with experimental evidence for their occurrence. (author)

  9. Publication and Retrieval of Computational Chemical-Physical Data Via the Semantic Web. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Ostlund, Neil [Chemical Semantics, Inc., Gainesville, FL (United States)

    2017-07-20

    This research showed the feasibility of applying the concepts of the Semantic Web to Computation Chemistry. We have created the first web portal (www.chemsem.com) that allows data created in the calculations of quantum chemistry, and other such chemistry calculations to be placed on the web in a way that makes the data accessible to scientists in a semantic form never before possible. The semantic web nature of the portal allows data to be searched, found, and used as an advance over the usual approach of a relational database. The semantic data on our portal has the nature of a Giant Global Graph (GGG) that can be easily merged with related data and searched globally via a SPARQL Protocol and RDF Query Language (SPARQL) that makes global searches for data easier than with traditional methods. Our Semantic Web Portal requires that the data be understood by a computer and hence defined by an ontology (vocabulary). This ontology is used by the computer in understanding the data. We have created such an ontology for computational chemistry (purl.org/gc) that encapsulates a broad knowledge of the field of computational chemistry. We refer to this ontology as the Gainesville Core. While it is perhaps the first ontology for computational chemistry and is used by our portal, it is only a start of what must be a long multi-partner effort to define computational chemistry. In conjunction with the above efforts we have defined a new potential file standard (Common Standard for eXchange – CSX for computational chemistry data). This CSX file is the precursor of data in the Resource Description Framework (RDF) form that the semantic web requires. Our portal translates CSX files (as well as other computational chemistry data files) into RDF files that are part of the graph database that the semantic web employs. We propose a CSX file as a convenient way to encapsulate computational chemistry data.

  10. TGT for chemistry learning to enhance students' achievement and critical thinking skills

    Science.gov (United States)

    Bolhassan, Norlailatulakma; Taha, Hafsah

    2017-05-01

    The form of cooperative learning known as Teams-Games-Tournament (TGT) in this study favors the use of teams work and learning tools combined with student play and practice to foster students' achievement and critical thinking skills. Using this paradigm, this study incorporates Teams-Games-Tournament and Flash Cards Games Kit during an 8-weeks experimental instruction period that includes 67 Form Four students; 34 students in the experimental group and 33 in the control group. The learning design in experimental group emphasizes scaffolding, guided practices, cooperative learning, and active participation in learning. While the experimental group experienced the TGT approach, the control group encountered the conventional teaching approach of chemistry drills. An achievement chemistry test and Watson Glaser Critical Thinking Appraisal (WGCTA) were used for the pretest and posttest. The finding indicates that TGT learning was more effective than drills in promoting chemistry performance, and the playful competiveness among students promotes students' critical thinking. In addition, TGT cooperative learning also creates an active learning environment in solving problems and discussions among students and teachers.

  11. Computational and experimental fluid mechanics. Progress report no. 5 for period January 1. to December 31. 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The general purpose of the program is the development of efficient algorithms, their implementation in codes of Computational Fluid Mechanics (CFD), and the experimental verification of these codes. Flows of both fundamental and applied nature will be investigated, including flows in industrial process equipment, about aerodynamics structures and ships, and flows over bed forms of importance for sediment transport. The experimental work will include the development of improved techniques, emphasizing optical methods. The objectives will be met through a coordinated experimental and theoretical/computational research program, organized in 7 specific projects: 1. CFD-methods and algorithms. 2. Spectral element simulation of ultrafiltration. 3. Turbulent swirling flows. 4. Near-wall models of turbulence. 5. Flow over bed forms. 6. Flow past ship hull. 7. Development of experimental techniques. (EG) 10 refs.

  12. Third Chemistry Conference on Recent Trends in Chemistry

    International Nuclear Information System (INIS)

    Saeed, M.M.; Wheed, S.

    2011-01-01

    The third chemistry conference 2011 on recent trends in chemistry was held from October 17-19, 2001 at Islamabad, Pakistan. More than 65 papers and oral presentation. The scope of the conference was wide open and provides and opportunity for participation of broad spectrum of chemists. This forum provided a platform for the dissemination of the latest research followed by discussion pertaining to new trends in chemistry. This con fence covered different aspects of subjects including analytical chemistry, environmental chemistry, polymer chemistry, industrial chemistry, biochemistry and nano chemistry etc. (A.B.)

  13. Preliminary experimentally-validated forced and mixed convection computational simulations of the Rotatable Buoyancy Tunnel

    International Nuclear Information System (INIS)

    Clifford, Corey E.; Kimber, Mark L.

    2015-01-01

    Although computational fluid dynamics (CFD) has not been directly utilized to perform safety analyses of nuclear reactors in the United States, several vendors are considering adopting commercial numerical packages for current and future projects. To ensure the accuracy of these computational models, it is imperative to validate the assumptions and approximations built into commercial CFD codes against physical data from flows analogous to those in modern nuclear reactors. To this end, researchers at Utah State University (USU) have constructed the Rotatable Buoyancy Tunnel (RoBuT) test facility, which is designed to provide flow and thermal validation data for CFD simulations of forced and mixed convection scenarios. In order to evaluate the ability of current CFD codes to capture the complex physics associated with these types of flows, a computational model of the RoBuT test facility is created using the ANSYS Fluent commercial CFD code. The numerical RoBuT model is analyzed at identical conditions to several experimental trials undertaken at USU. Each experiment is reconstructed numerically and evaluated with the second-order Reynolds stress model (RSM). Two different thermal boundary conditions at the heated surface of the RoBuT test section are investigated: constant temperature (isothermal) and constant surface heat flux (isoflux). Additionally, the fluid velocity at the inlet of the test section is varied in an effort to modify the relative importance of natural convection heat transfer from the heated wall of the RoBuT. Mean velocity, both in the streamwise and transverse directions, as well as components of the Reynolds stress tensor at three points downstream of the RoBuT test section inlet are compared to results obtained from experimental trials. Early computational results obtained from this research initiative are in good agreement with experimental data obtained from the RoBuT facility and both the experimental data and numerical method can be used

  14. The use of domestic microwave oven in experimental classes of organic chemistry: salicylaldehyde nitration

    OpenAIRE

    Teixeira, Eurídes Francisco; Santos, Ana Paula Bernardo dos; Bastos, Renato Saldanha; Pinto, Angelo C.; Kümmerle, Arthur Eugen; Coelho, Roberto Rodrigues

    2010-01-01

    The use of microwave in chemistry has known benefits over conventional heating methods, e.g. reduced reaction times, chemical yield improvement and the possibility if reducing or eliminating the use of organic solvents. We describe herein a procedure for the nitration of salicylaldehyde in water using a domestic microwave oven, which can be used as an experiment in the undergraduate chemistry laboratory. The experiment involves safe and rapid preparation and identification of the position iso...

  15. Progress report 1985-1986 Reactor Chemistry Department

    International Nuclear Information System (INIS)

    1987-12-01

    The report of the activities performed by the Reactor Chemistry Department of the National Atomic Energy Commission, during the period 1985-1986, covers works of investigation, development and service related to the Argentine Nuclear Power Plants. The main subjects are the experimental and theoretical studies about physical chemistry and chemistry control at the moderators and heat transport system of the nuclear power plants. The more relevant topics are related to: 1: Behaviour of gases, electrolites and other additives for nuclear power plants, at high temperature and pressure; 2: Ionic exchangers of nuclear degree; 3: Electrochemistry studies connected with the constitutive materials' corrosion and with the nuclear power plants decontamination processes; 4: Behaviour of suspensions and colloids in nuclear power plants; 5: Use of new additives for chemistry control of the oxides which are in the circuits of nuclear power plants; 6: Research methods that allow to check reactor's control quality; 7: Study of the radiolytic behaviour of nuclear reactor's solutions. (M.E.L.) [es

  16. Predicting steam generator crevice chemistry

    International Nuclear Information System (INIS)

    Burton, G.; Strati, G.

    2006-01-01

    'Full text:' Corrosion of steam cycle components produces insoluble material, mostly iron oxides, that are transported to the steam generator (SG) via the feedwater and deposited on internal surfaces such as the tubes, tube support plates and the tubesheet. The build up of these corrosion products over time can lead to regions of restricted flow with water chemistry that may be significantly different, and potentially more corrosive to SG tube material, than the bulk steam generator water chemistry. The aim of the present work is to predict SG crevice chemistry using experimentation and modelling as part of AECL's overall strategy for steam generator life management. Hideout-return experiments are performed under CANDU steam generator conditions to assess the accumulation of impurities in hideout, and return from, model crevices. The results are used to validate the ChemSolv model that predicts steam generator crevice impurity concentrations, and high temperature pH, based on process parameters (e.g., heat flux, primary side temperature) and blowdown water chemistry. The model has been incorporated into ChemAND, AECL's system health monitoring software for chemistry monitoring, analysis and diagnostics that has been installed at two domestic and one international CANDU station. ChemAND provides the station chemists with the only method to predict SG crevice chemistry. In one recent application, the software has been used to evaluate the crevice chemistry based on the elevated, but balanced, SG bulk water impurity concentrations present during reactor startup, in order to reduce hold times. The present paper will describe recent hideout-return experiments that are used for the validation of the ChemSolv model, station experience using the software, and improvements to predict the crevice electrochemical potential that will permit station staff to ensure that the SG tubes are in the 'safe operating zone' predicted by Lu (AECL). (author)

  17. Experimental realization of a one-way quantum computer algorithm solving Simon's problem.

    Science.gov (United States)

    Tame, M S; Bell, B A; Di Franco, C; Wadsworth, W J; Rarity, J G

    2014-11-14

    We report an experimental demonstration of a one-way implementation of a quantum algorithm solving Simon's problem-a black-box period-finding problem that has an exponential gap between the classical and quantum runtime. Using an all-optical setup and modifying the bases of single-qubit measurements on a five-qubit cluster state, key representative functions of the logical two-qubit version's black box can be queried and solved. To the best of our knowledge, this work represents the first experimental realization of the quantum algorithm solving Simon's problem. The experimental results are in excellent agreement with the theoretical model, demonstrating the successful performance of the algorithm. With a view to scaling up to larger numbers of qubits, we analyze the resource requirements for an n-qubit version. This work helps highlight how one-way quantum computing provides a practical route to experimentally investigating the quantum-classical gap in the query complexity model.

  18. The Computer Revolution and Physical Chemistry.

    Science.gov (United States)

    O'Brien, James F.

    1989-01-01

    Describes laboratory-oriented software programs that are short, time-saving, eliminate computational errors, and not found in public domain courseware. Program availability for IBM and Apple microcomputers is included. (RT)

  19. Experimental and Computer Modelling Studies of Metastability of Amorphous Silicon Based Solar Cells

    NARCIS (Netherlands)

    Munyeme, Geoffrey

    2003-01-01

    We present a combination of experimental and computer modelling studies of the light induced degradation in the performance of amorphous silicon based single junction solar cells. Of particular interest in this study is the degradation kinetics of different types of amorphous silicon single junction

  20. Instructional Model and Thinking Skill in Chemistry Class

    Science.gov (United States)

    Langkudi, H. H.

    2018-02-01

    Chemistry course are considered a difficult lesson for students as evidenced by low learning outcomes on daily tests, mid-semester tests as well as final semester tests. This research intended to investigate the effect of instructional model, thinking skill and the interaction of these variables on students’ achievement in chemistry. Experimental method was applying used 2 x 2 factorial design. The results showed that the use of instructional model with thinking skill influences student’s learning outcomes, so that the chemistry teacher is recommended to pay attention to the learning model, and adjusted to the student’s skill thinking on the chemistry material being taught. The conclusion of this research is that discovery model is suitable for students who have formal thinking skill and conventional model is fit for the students that have concrete thinking skill.

  1. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    Science.gov (United States)

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  2. Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

    Energy Technology Data Exchange (ETDEWEB)

    Holm, J.; Ekberg, C. (Chalmers Univ. of Technology, Goeteborg (Sweden)); Kaerkelae, T.; Auvinen, A. (VTT, Espoo (Finland)); Glaenneskog, H. (Vattenfall Power Consultant, Goeteborg (Sweden))

    2011-05-15

    An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment, was started. During year 2008 (NROI-1) the radiolytic oxidation of elemental iodine was investigated and during 2009 (NROI-2), the radiolytic oxidation of organic iodine was studied. This project (NROI-3) is a continuation of the investigation of the oxidation of organic iodine. The project has been divided into two parts. 1. The aims of the first part were to investigate the effect of ozone and UV-radiation, in dry and humid conditions, on methyl iodide. 2. The second project was about gamma radiation (approx20 kGy/h) and methyl iodide in dry and humid conditions. 1. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UV-radiation intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. The particle formation was instant and extensive when methyl iodide was exposed to ozone and/or radiation at all temperatures. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-200 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine oxides (I{sub xO{sub y}). However, the correct speciation of the formed particles was difficult to obtain because the particles melted and fused together under the electron beam. 2. The results from this sub-project are more inconsistent and hard to interpret. The particle formation was significant lesser than corresponding experiments when ozone/UV-radiation was used instead of gamma radiation. The transport of gaseous methyl iodide through the facility was

  3. Visually impaired researchers get their hands on quantum chemistry: application to a computational study on the isomerization of a sterol

    Science.gov (United States)

    Lounnas, Valère; Wedler, Henry B.; Newman, Timothy; Schaftenaar, Gijs; Harrison, Jason G.; Nepomuceno, Gabriella; Pemberton, Ryan; Tantillo, Dean J.; Vriend, Gert

    2014-11-01

    In molecular sciences, articles tend to revolve around 2D representations of 3D molecules, and sighted scientists often resort to 3D virtual reality software to study these molecules in detail. Blind and visually impaired (BVI) molecular scientists have access to a series of audio devices that can help them read the text in articles and work with computers. Reading articles published in this journal, though, is nearly impossible for them because they need to generate mental 3D images of molecules, but the article-reading software cannot do that for them. We have previously designed AsteriX, a web server that fully automatically decomposes articles, detects 2D plots of low molecular weight molecules, removes meta data and annotations from these plots, and converts them into 3D atomic coordinates. AsteriX-BVI goes one step further and converts the 3D representation into a 3D printable, haptic-enhanced format that includes Braille annotations. These Braille-annotated physical 3D models allow BVI scientists to generate a complete mental model of the molecule. AsteriX-BVI uses Molden to convert the meta data of quantum chemistry experiments into BVI friendly formats so that the entire line of scientific information that sighted people take for granted—from published articles, via printed results of computational chemistry experiments, to 3D models—is now available to BVI scientists too. The possibilities offered by AsteriX-BVI are illustrated by a project on the isomerization of a sterol, executed by the blind co-author of this article (HBW).

  4. Teaching a Chemistry MOOC with a Virtual Laboratory: Lessons Learned from an Introductory Physical Chemistry Course

    Science.gov (United States)

    O'Malley, Patrick J.; Agger, Jonathan R.; Anderson, Michael W.

    2015-01-01

    An analysis is presented of the experience and lessons learned of running a MOOC in introductory physical chemistry. The course was unique in allowing students to conduct experimental measurements using a virtual laboratory constructed using video and simulations. A breakdown of the student background and motivation for taking the course is…

  5. Radiation chemistry

    International Nuclear Information System (INIS)

    Rodgers, F.; Rodgers, M.A.

    1987-01-01

    The contents of this book include: Interaction of ionizing radiation with matter; Primary products in radiation chemistry; Theoretical aspects of radiation chemistry; Theories of the solvated electron; The radiation chemistry of gases; Radiation chemistry of colloidal aggregates; Radiation chemistry of the alkali halides; Radiation chemistry of polymers; Radiation chemistry of biopolymers; Radiation processing and sterilization; and Compound index

  6. Characteristic thermal-hydraulic problems in NHRs: Overview of experimental investigations and computer codes

    Energy Technology Data Exchange (ETDEWEB)

    Falikov, A A; Vakhrushev, V V; Kuul, V S; Samoilov, O B; Tarasov, G I [OKBM, Nizhny Novgorod (Russian Federation)

    1997-09-01

    The paper briefly reviews the specific thermal-hydraulic problems for AST-type NHRs, the experimental investigations that have been carried out in the RF, and the design procedures and computer codes used for AST-500 thermohydraulic characteristics and safety validation. (author). 13 refs, 10 figs, 1 tab.

  7. Web-based computational chemistry education with CHARMMing III: Reduction potentials of electron transfer proteins.

    Directory of Open Access Journals (Sweden)

    B Scott Perrin

    2014-07-01

    Full Text Available A module for fast determination of reduction potentials, E°, of redox-active proteins has been implemented in the CHARMM INterface and Graphics (CHARMMing web portal (www.charmming.org. The free energy of reduction, which is proportional to E°, is composed of an intrinsic contribution due to the redox site and an environmental contribution due to the protein and solvent. Here, the intrinsic contribution is selected from a library of pre-calculated density functional theory values for each type of redox site and redox couple, while the environmental contribution is calculated from a crystal structure of the protein using Poisson-Boltzmann continuum electrostatics. An accompanying lesson demonstrates a calculation of E°. In this lesson, an ionizable residue in a [4Fe-4S]-protein that causes a pH-dependent E° is identified, and the E° of a mutant that would test the identification is predicted. This demonstration is valuable to both computational chemistry students and researchers interested in predicting sequence determinants of E° for mutagenesis.

  8. Simulation of the vibrational chemistry and the infrared signature induced by a Sprite streamer in the mesosphere

    Science.gov (United States)

    Romand, F.; Payan, S.; Croize, L.

    2017-12-01

    Since their first observation in 1989, effect of TLEs on the atmospheric composition has become an open and important question. The lack of suitable experimental data is a shortcoming that hampers our understanding of the physics and chemistry induced by these effects. HALESIS (High-Altitude Luminous Events Studied by Infrared Spectro-imagery) is a future experiment dedicated to the measurement of the atmospheric perturbation induced by a TLE in the minutes following its occurrence, from a stratospheric balloon flying at an altitude of 25 km to 40 km. This work aims to quantify the local chemical impact of sprites in the stratosphere and mesosphere. In this paper, we will present the development of a tool which simulates (i) the impact of a sprite on the vibrational chemistry, (ii) the resulting infrared signature and (iii) the propagation of this signature through the atmosphere to an observer. First the Non Local Thermodynamic Equilibrium populations of a background atmosphere were computed using SAMM2 code. The initial thermodynamic and chemical description of atmosphere comes from the Whole Atmosphere community Climate Model (WACCM). Then a perturbation was applied to simulate a sprite. Chemistry due to TLEs was computed using Gordillo-Vazquez kinetic model. Rate coefficients that depend on the electron energy distribution function were calculated from collision cross-section data by solving the electron Boltzmann equation (BE). Time evolutions of the species densities and of vibrational populations in the non-thermal plasma consecutive to sprite discharge were simulated using the computer code ZDPlasKin (S. Pancheshn et al.). Finally, the resulting infrared signatures were propagated from the disturbed area through the atmosphere to an instrument placed in a limb line of sight using a line by line radiative transfer model. We will conclude that sprite could produce a significant infrared signature that last a few tens of seconds after the visible flash.

  9. Experimental proposals for procedures to investigate the water chemistry, sorption and transport properties of marl

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Baeyens, B.; Alexander, W.R.

    1990-11-01

    The aim of this report is to describe a framework within which laboratory studies on groundwater chemistry, sorption and transport properties might be conducted on samples from rock formations being considered as potential 'host rocks' for the disposal of radioactive waste. Here, Valanginian marl, has been taken as a specific example, but the general principles should be applicable to other systems. Some brief notes are given on sampling and handling procedures and mineralogical characterisation. This is followed by a detailed discussion of the procedures considered necessary to determine a groundwater chemistry of a specific rock matrix. The methods described are particularly appropriate to rocks such as marl i.e. low water content rocks (essentially 'dry') with appreciable clay and carbonate contents. An important conclusion drawn is that simple aqueous phase extractions at different liquid to solid ratios, followed by extrapolation procedures, are not always appropriate and can lead to incorrect water compositions. Some of the uncertainties and difficulties inherently involved in determining sorption parameters from batch, infiltration and diffusion based methods are presented. These methods are then individually discussed in greater detail with some illustrative examples. In the relatively few studies where sorption has been measured in crushed rock tests and compared with the results from intact rock experiments, it is often found that there are discrepancies. An outline for an experiment is described in which results from the two types of test could be quantitatively related to one another via cation exchange capacity measurements. Using this method it might be possible to explain the reasons for such discrepancies. Finally, a brief discussion is given on the possible consequences for experimental studies of gas in Valanginian marl and the swelling of the clay rich components. (author) 8 figs., 4 tabs., 46 refs

  10. Experimental assessment of computer codes used for safety analysis of integral reactors

    Energy Technology Data Exchange (ETDEWEB)

    Falkov, A.A.; Kuul, V.S.; Samoilov, O.B. [OKB Mechanical Engineering, Nizhny Novgorod (Russian Federation)

    1995-09-01

    Peculiarities of integral reactor thermohydraulics in accidents are associated with presence of noncondensable gas in built-in pressurizer, absence of pumped ECCS, use of guard vessel for LOCAs localisation and passive RHRS through in-reactor HX`s. These features defined the main trends in experimental investigations and verification efforts for computer codes applied. The paper reviews briefly the performed experimental investigation of thermohydraulics of AST-500, VPBER600-type integral reactors. The characteristic of UROVEN/MB-3 code for LOCAs analysis in integral reactors and results of its verification are given. The assessment of RELAP5/mod3 applicability for accident analysis in integral reactor is presented.

  11. Computational chemistry in pharmaceutical research: at the crossroads.

    Science.gov (United States)

    Bajorath, Jürgen

    2012-01-01

    Computational approaches are an integral part of pharmaceutical research. However, there are many of unsolved key questions that limit the scientific progress in the still evolving computational field and its impact on drug discovery. Importantly, a number of these questions are not new but date back many years. Hence, it might be difficult to conclusively answer them in the foreseeable future. Moreover, the computational field as a whole is characterized by a high degree of heterogeneity and so is, unfortunately, the quality of its scientific output. In light of this situation, it is proposed that changes in scientific standards and culture should be seriously considered now in order to lay a foundation for future progress in computational research.

  12. Fragment informatics and computational fragment-based drug design: an overview and update.

    Science.gov (United States)

    Sheng, Chunquan; Zhang, Wannian

    2013-05-01

    Fragment-based drug design (FBDD) is a promising approach for the discovery and optimization of lead compounds. Despite its successes, FBDD also faces some internal limitations and challenges. FBDD requires a high quality of target protein and good solubility of fragments. Biophysical techniques for fragment screening necessitate expensive detection equipment and the strategies for evolving fragment hits to leads remain to be improved. Regardless, FBDD is necessary for investigating larger chemical space and can be applied to challenging biological targets. In this scenario, cheminformatics and computational chemistry can be used as alternative approaches that can significantly improve the efficiency and success rate of lead discovery and optimization. Cheminformatics and computational tools assist FBDD in a very flexible manner. Computational FBDD can be used independently or in parallel with experimental FBDD for efficiently generating and optimizing leads. Computational FBDD can also be integrated into each step of experimental FBDD and help to play a synergistic role by maximizing its performance. This review will provide critical analysis of the complementarity between computational and experimental FBDD and highlight recent advances in new algorithms and successful examples of their applications. In particular, fragment-based cheminformatics tools, high-throughput fragment docking, and fragment-based de novo drug design will provide the focus of this review. We will also discuss the advantages and limitations of different methods and the trends in new developments that should inspire future research. © 2012 Wiley Periodicals, Inc.

  13. Sensitivity Measurement of Transmission Computer Tomography: thePreliminary Experimental Study

    International Nuclear Information System (INIS)

    Widodo, Chomsin-S; Sudjatmoko; Kusminarto; Agung-BS Utomo; Suparta, Gede B

    2000-01-01

    This paper reports result of preliminary experimental study onmeasurement method for sensitivity of a computed tomography (CT) scanner. ACT scanner has been build at the Department of Physics, FMIPA UGM and itsperformance based on its sensitivity was measured. The result showed that themeasurement method for sensitivity confirmed this method may be developedfurther as a measurement standard. Although the CT scanner developed has anumber of shortcoming, the analytical results from the sensitivitymeasurement suggest a number of reparations and improvements for the systemso that improved reconstructed CT images can be obtained. (author)

  14. Per-Olov Löwdin - father of quantum chemistry

    Science.gov (United States)

    Brändas, Erkki J.

    2017-09-01

    During 2016, we celebrate the 100th anniversary of the birth of Per-Olov Löwdin. He was appointed to the first Lehrstuhl in quantum chemistry at Uppsala University in 1960. Löwdin introduced quantum chemistry as a field in its own right by formulating its goals, establishing fundamental concepts, like the correlation energy, the method of configuration interaction, reduced density matrices, natural spin orbitals, charge and bond order matrices, symmetric orthogonalisation, and generalised self-consistent fields. His exposition of partitioning technique and perturbation theory, wave and reaction operators and associated non-linear summation techniques, introduced mathematical rigour and deductive order in the interpretative organisation of the new field. He brought the first computer to Uppsala University and pioneered the initiation of 'electronic brains' and anticipated their significance for quantum chemistry. Perhaps his single most influential contribution to the field was his education of two generations of future faculty in quantum chemistry through Summer Schools in the Scandinavian Mountains, Winter Institutes at Sanibel Island in the Gulf of Mexico. Per-Olov Löwdin founded the book series Advances in Quantum Chemistry and the International Journal of Quantum Chemistry. The evolution of quantum chemistry is appraised, starting from a collection of cross-disciplinary applications of quantum mechanics to the technologically advanced and predominant field of today, virtually used in all branches of chemistry. The scientific work of Per-Olov Löwdin has been crucial for the development of this new important province of science.

  15. Computational Experimentation to Understand C2 for Teams of Autonomous Systems and People

    Science.gov (United States)

    2014-12-12

    Muller, J. 9/26/2012. With Driverless Cars, Once Again It Is California Leading The Way. Forbes; http://www.forbes.com/sites/joannmuller/2012/09...26/with- driverless -cars- once-again-it-is-california-leading-the-way/; retrieved 09/19/2013. Nissen, M.E. 2007. Computational Experimentation on New

  16. Experimental and computational analysis of steam condensation in the presence of air and helium

    International Nuclear Information System (INIS)

    Bucci, M.

    2010-01-01

    Among the different phenomena expected to occur within nuclear reactor containments during a postulated loss of coolant accident, condensation on containment walls plays a major role, since it represents an important heat sink for evacuating the energy released by the discharge of the primary water. Nevertheless, condensation strongly affects other relevant phenomena, like containment atmosphere mixing, that influences the distribution of non-condensable gases hypothetically delivered in severe accident conditions. In this scenario, the role of condensation is not obvious, since it can locally aid the hydrogen produced by the oxidation of the core claddings to concentrate and reach flammability limits, providing a dangerous effect instead of a positive one. The understanding of condensation in the presence of air and hydrogen is therefore a fundamental task for the safety analyses of reactor containments. This research has been carried out with the aim to contribute to the understanding of these phenomena. A double strategy has been adopted, including complementary experimental and computational activities. Novel data have been made available by the CONAN facility, investigating the effects induced by light non-condensable gases in experimental configurations that were scarcely investigated in past studies. Computational fluid dynamics (CFD) condensation models have been developed and validated. The suitability of helium as a substitute for hydrogen in experimental activities has been investigated by theoretical and computational analyses allowing to establish simple criteria for the scaling of condensation tests in the presence of a light non-condensable gas. (authors)

  17. Computer-Based Molecular Modelling: Finnish School Teachers' Experiences and Views

    Science.gov (United States)

    Aksela, Maija; Lundell, Jan

    2008-01-01

    Modern computer-based molecular modelling opens up new possibilities for chemistry teaching at different levels. This article presents a case study seeking insight into Finnish school teachers' use of computer-based molecular modelling in teaching chemistry, into the different working and teaching methods used, and their opinions about necessary…

  18. Theoretical chemistry periodicities in chemistry and biology

    CERN Document Server

    Eyring, Henry

    1978-01-01

    Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

  19. COMPUTATIONAL SCIENCE CENTER

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT, J.

    2005-11-01

    The Brookhaven Computational Science Center brings together researchers in biology, chemistry, physics, and medicine with applied mathematicians and computer scientists to exploit the remarkable opportunities for scientific discovery which have been enabled by modern computers. These opportunities are especially great in computational biology and nanoscience, but extend throughout science and technology and include, for example, nuclear and high energy physics, astrophysics, materials and chemical science, sustainable energy, environment, and homeland security. To achieve our goals we have established a close alliance with applied mathematicians and computer scientists at Stony Brook and Columbia Universities.

  20. Proceedings of the DAE-BRNS fourth interdisciplinary symposium on materials chemistry

    International Nuclear Information System (INIS)

    Tyagi, D.; Banerjee, A.M.; Bhattacharyya, K.; Nigam, S.; Varma, S.; Tripathi, A.K.; Das, D.

    2012-12-01

    This symposium covers almost all the contemporary research areas of materials chemistry like materials for energy conversion, biomaterials, carbon based materials, chemical sensors, fuel cell materials and other electro-ceramics, polymers and soft condensed matters, thin films and surface chemistry, organic and organometallics, high purity materials, nanomaterials and clusters to acquaint ourselves with the advancement made in these emerging areas. Topics like nuclear materials, magnetic materials, catalysis and computational materials chemistry continue to be important facet of ISMC series of symposia. Papers relevant to INIS are indexed separately

  1. Implementation of Premixed Equilibrium Chemistry Capability in OVERFLOW

    Science.gov (United States)

    Olsen, Mike E.; Liu, Yen; Vinokur, M.; Olsen, Tom

    2004-01-01

    An implementation of premixed equilibrium chemistry has been completed for the OVERFLOW code, a chimera capable, complex geometry flow code widely used to predict transonic flowfields. The implementation builds on the computational efficiency and geometric generality of the solver.

  2. [Towards computer-aided catalyst design: Three effective core potential studies of C-H activation]. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    Research in the initial grant period focused on computational studies relevant to the selective activation of methane, the prime component of natural gas. Reaction coordinates for methane activation by experimental models were delineated, as well as the bonding and structure of complexes that effect this important reaction. This research, highlighted in the following sections, also provided the impetus for further development, and application of methods for modeling metal-containing catalysts. Sections of the report describe the following: methane activation by multiple-bonded transition metal complexes; computational lanthanide chemistry; and methane activation by non-imido, multiple-bonded ligands.

  3. SWIFT: Semi-empirical and numerically efficient stratospheric ozone chemistry for global climate models

    OpenAIRE

    Kreyling, Daniel; Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2015-01-01

    The SWIFT model is a fast yet accurate chemistry scheme for calculating the chemistry of stratospheric ozone. It is mainly intended for use in Global Climate Models (GCMs), Chemistry Climate Models (CCMs) and Earth System Models (ESMs). For computing time reasons these models often do not employ full stratospheric chem- istry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chem...

  4. KEEFEKTIFAN INKUIRI TERBIMBING BERORIENTASI GREEN CHEMISTRY TERHADAP KETERAMPILAN PROSES SAINS

    Directory of Open Access Journals (Sweden)

    Nur Amalia Afiyanti

    2015-11-01

    Full Text Available This research aims to know the effectiveness of guided inquiry oriented green chemistry for science process skills at XI school grade of SMA in Semarang on 2012/2013 period. The population is normal and homogeneous, so to take two groups of samples using cluster random sampling techniques. Design of this research is posttest only control design. The succes of this research seen from cognitive aspect of student achievement reach KKM. At the final stage of the analysis, the t test used was left-test with t count > t table (1.696. The student achievement for experimental classes obtained t count of 3.860 while the control class 0,914. This suggests that the experimental class has achieved mastery learning, while the control class not yet. The average value of the psychomotor aspects of students in the experimental class was 82.6 which is included in the excellent category and control class was 74 included in good category. In the aspect of Students environmental concern, the average value of the experimental class was 88.65 included in the excellent category and class control was 81.7 included in good category. The conclusion was that the research-oriented guided inquiry of green chemistry proved effectively increase the science process skills.Keywords: Green Chemistry, Guided Inquiry, Science Process Skills

  5. Synergy between experimental and theoretical methods in the exploration of homogeneous transition metal catalysis

    DEFF Research Database (Denmark)

    Lupp, Daniel; Christensen, Niels Johan; Fristrup, Peter

    2014-01-01

    n this Perspective, we will focus on the use of both experimental and theoretical methods in the exploration of reaction mechanisms in homogeneous transition metal catalysis. We briefly introduce the use of Hammett studies and kinetic isotope effects (KIE). Both of these techniques can be complem......n this Perspective, we will focus on the use of both experimental and theoretical methods in the exploration of reaction mechanisms in homogeneous transition metal catalysis. We briefly introduce the use of Hammett studies and kinetic isotope effects (KIE). Both of these techniques can...... be complemented by computational chemistry – in particular in cases where interpretation of the experimental results is not straightforward. The good correspondence between experiment and theory is only possible due to recent advances within the applied theoretical framework. We therefore also highlight...

  6. Experimental demonstration of reservoir computing on a silicon photonics chip

    Science.gov (United States)

    Vandoorne, Kristof; Mechet, Pauline; van Vaerenbergh, Thomas; Fiers, Martin; Morthier, Geert; Verstraeten, David; Schrauwen, Benjamin; Dambre, Joni; Bienstman, Peter

    2014-03-01

    In today’s age, companies employ machine learning to extract information from large quantities of data. One of those techniques, reservoir computing (RC), is a decade old and has achieved state-of-the-art performance for processing sequential data. Dedicated hardware realizations of RC could enable speed gains and power savings. Here we propose the first integrated passive silicon photonics reservoir. We demonstrate experimentally and through simulations that, thanks to the RC paradigm, this generic chip can be used to perform arbitrary Boolean logic operations with memory as well as 5-bit header recognition up to 12.5 Gbit s-1, without power consumption in the reservoir. It can also perform isolated spoken digit recognition. Our realization exploits optical phase for computing. It is scalable to larger networks and much higher bitrates, up to speeds >100 Gbit s-1. These results pave the way for the application of integrated photonic RC for a wide range of applications.

  7. Artificial soils from alluvial tin mining wastes in Malaysia--a study of soil chemistry following experimental treatments and the impact of mycorrhizal treatment on growth and foliar chemistry.

    Science.gov (United States)

    Tompkins, David S; Bakar, Baki B; Hill, Steve J

    2012-01-01

    For decades Malaysia was the world's largest producer of Sn, but now the vast open cast mining operations have left a legacy of some 100,000 ha of what is effectively wasteland, covered with a mosaic of tailings and lagoons. Few plants naturally recolonise these areas. The demand for such land for both urban expansion and agricultural use has presented an urgent need for better characterisation. This study reports on the formation of artificial soils from alluvial Sn mining waste with a focus on the effects of experimental treatments on soil chemistry. Soil organic matter, clay, and pH were manipulated in a controlled environment. Adding both clay tailings and peat enhanced the cation exchange capacity of sand tailings but also reduced the pH. The addition of peat reduced the extractable levels of some elements but increased the availability of Ca and Mg, thus proving beneficial. The use of clay tailings increased the levels of macro and micronutrients but also released Al, As, La, Pb and U. Additionally, the effects of soil mix and mycorrhizal treatments on growth and foliar chemistry were studied. Two plant species were selected: Panicum milicaeum and Pueraria phaseoloides. Different growth patterns were observed with respect to the additions of peat and clay. The results for mycorrhizal treatment (live inoculum or sterile carrier medium) are more complex, but both resulted in improved growth. The use of mycorrhizal fungi could greatly enhance rehabilitation efforts on sand tailings.

  8. On-line gas chemistry experiments with trans actinide elements

    International Nuclear Information System (INIS)

    Turler, A.; Gaguller, B.; Jost, D.T.

    1993-01-01

    The latest achievements in the gas phase chemistry studies of elements 104 and 105 and their lighter homologs are reviewed. Experimental techniques employed in the studies are described. Experimental data on chlorides and bromides of the groups 4, 5 elements and elements 104, 105 are compared with their theoretically predicted chemical properties. 45 refs

  9. Students' Learning with the Connected Chemistry (CC1) Curriculum: Navigating the Complexities of the Particulate World

    Science.gov (United States)

    Levy, Sharona T.; Wilensky, Uri

    2009-01-01

    The focus of this study is students' learning with a Connected Chemistry unit, CC1 (denotes Connected Chemistry, chapter 1), a computer-based environment for learning the topics of gas laws and kinetic molecular theory in chemistry (Levy and Wilensky 2009). An investigation was conducted into high-school students' learning with Connected…

  10. Structural and Thermodynamic Properties of the Argon Dimer: A Computational Chemistry Exercise in Quantum and Statistical Mechanics

    Science.gov (United States)

    Halpern, Arthur M.

    2010-01-01

    Using readily available computational applications and resources, students can construct a high-level ab initio potential energy surface (PES) for the argon dimer. From this information, they can obtain detailed molecular constants of the dimer, including its dissociation energy, which compare well with experimental determinations. Using both…

  11. Emerging experimental and computational technologies for purpose designed engineering of photosynthetic prokaryotes

    KAUST Repository

    Lindblad, Peter

    2016-01-25

    With recent advances in synthetic molecular tools to be used in photosynthetic prokaryotes, like cyanobacteria, it is possible to custom design and construct microbial cells for specific metabolic functions. This cross-disciplinary area of research has emerged within the interfaces of advanced genetic engineering, computational science, and molecular biotechnology. We have initiated the development of a genetic toolbox, using a synthetic biology approach, to custom design, engineer and construct cyanobacteria for selected function and metabolism. One major bottleneck is a controlled transcription and translation of introduced genetic constructs. An additional major issue is genetic stability. I will present and discuss recent progress in our development of genetic tools for advanced cyanobacterial biotechnology. Progress on understanding the electron pathways in native and engineered cyanobacterial enzymes and heterologous expression of non-native enymzes in cyanobacterial cells will be highlighted. Finally, I will discuss our attempts to merge synthetic biology with synthetic chemistry to explore fundamantal questions of protein design and function.

  12. Toward efficient computation of the expected relative entropy for nonlinear experimental design

    International Nuclear Information System (INIS)

    Coles, Darrell; Prange, Michael

    2012-01-01

    The expected relative entropy between prior and posterior model-parameter distributions is a Bayesian objective function in experimental design theory that quantifies the expected gain in information of an experiment relative to a previous state of knowledge. The expected relative entropy is a preferred measure of experimental quality because it can handle nonlinear data-model relationships, an important fact due to the ubiquity of nonlinearity in science and engineering and its effects on post-inversion parameter uncertainty. This objective function does not necessarily yield experiments that mediate well-determined systems, but, being a Bayesian quality measure, it rigorously accounts for prior information which constrains model parameters that may be only weakly constrained by the optimized dataset. Historically, use of the expected relative entropy has been limited by the computing and storage requirements associated with high-dimensional numerical integration. Herein, a bifocal algorithm is developed that makes these computations more efficient. The algorithm is demonstrated on a medium-sized problem of sampling relaxation phenomena and on a large problem of source–receiver selection for a 2D vertical seismic profile. The method is memory intensive but workarounds are discussed. (paper)

  13. Experimental and computational analysis of pressure response in a multiphase flow loop

    Science.gov (United States)

    Morshed, Munzarin; Amin, Al; Rahman, Mohammad Azizur; Imtiaz, Syed

    2016-07-01

    The characteristics of multiphase fluid flow in pipes are useful to understand fluid mechanics encountered in the oil and gas industries. In the present day oil and gas exploration is successively inducing subsea operation in the deep sea and arctic condition. During the transport of petroleum products, understanding the fluid dynamics inside the pipe network is important for flow assurance. In this case the information regarding static and dynamic pressure response, pressure loss, optimum flow rate, pipe diameter etc. are the important parameter for flow assurance. The principal aim of this research is to represents computational analysis and experimental analysis of multi-phase (L/G) in a pipe network. This computational study considers a two-phase fluid flow through a horizontal flow loop with at different Reynolds number in order to determine the pressure distribution, frictional pressure loss profiles by volume of fluid (VOF) method. However, numerical simulations are validated with the experimental data. The experiment is conducted in 76.20 mm ID transparent circular pipe using water and air in the flow loop. Static pressure transducers are used to measure local pressure response in multiphase pipeline.

  14. Complex chemistry

    International Nuclear Information System (INIS)

    Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

    2006-06-01

    This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

  15. Experimental/Computational Approach to Accommodation Coefficients and its Application to Noble Gases on Aluminum Surface (Preprint)

    Science.gov (United States)

    2009-02-03

    computational approach to accommodation coefficients and its application to noble gases on aluminum surface Nathaniel Selden Uruversity of Southern Cahfornia, Los ...8217 ,. 0.’ a~ .......,..,P. • " ,,-0, "p"’U".. ,Po"D.’ 0.’P.... uro . P." FIG. 5: Experimental and computed radiometri~ force for argon (left), xenon

  16. Enabling new capabilities and insights from quantum chemistry by using component architectures

    International Nuclear Information System (INIS)

    Janssen, C L; Kenny, J P; Nielsen, I M B; Krishnan, M; Gurumoorthi, V; Valeev, E F; Windus, T L

    2006-01-01

    Steady performance gains in computing power, as well as improvements in Scientific computing algorithms, are making possible the study of coupled physical phenomena of great extent and complexity. The software required for such studies is also very complex and requires contributions from experts in multiple disciplines. We have investigated the use of the Common Component Architecture (CCA) as a mechanism to tackle some of the resulting software engineering challenges in quantum chemistry, focusing on three specific application areas. In our first application, we have developed interfaces permitting solvers and quantum chemistry packages to be readily exchanged. This enables our quantum chemistry packages to be used with alternative solvers developed by specialists, remedying deficiencies we discovered in the native solvers provided in each of the quantum chemistry packages. The second application involves development of a set of components designed to improve utilization of parallel machines by allowing multiple components to execute concurrently on subsets of the available processors. This was found to give substantial improvements in parallel scalability. Our final application is a set of components permitting different quantum chemistry packages to interchange intermediate data. These components enabled the investigation of promising new methods for obtaining accurate thermochemical data for reactions involving heavy elements

  17. Comparison between a Computational Seated Human Model and Experimental Verification Data

    Directory of Open Access Journals (Sweden)

    Christian G. Olesen

    2014-01-01

    Full Text Available Sitting-acquired deep tissue injuries (SADTI are the most serious type of pressure ulcers. In order to investigate the aetiology of SADTI a new approach is under development: a musculo-skeletal model which can predict forces between the chair and the human body at different seated postures. This study focuses on comparing results from a model developed in the AnyBody Modeling System, with data collected from an experimental setup. A chair with force-measuring equipment was developed, an experiment was conducted with three subjects, and the experimental results were compared with the predictions of the computational model. The results show that the model predicted the reaction forces for different chair postures well. The correlation coefficients of how well the experiment and model correlate for the seat angle, backrest angle and footrest height was 0.93, 0.96, and 0.95. The study show a good agreement between experimental data and model prediction of forces between a human body and a chair. The model can in the future be used in designing wheelchairs or automotive seats.

  18. A survey of upwind methods for flows with equilibrium and non-equilibrium chemistry and thermodynamics

    Science.gov (United States)

    Grossman, B.; Garrett, J.; Cinnella, P.

    1989-01-01

    Several versions of flux-vector split and flux-difference split algorithms were compared with regard to general applicability and complexity. Test computations were performed using curve-fit equilibrium air chemistry for an M = 5 high-temperature inviscid flow over a wedge, and an M = 24.5 inviscid flow over a blunt cylinder for test computations; for these cases, little difference in accuracy was found among the versions of the same flux-split algorithm. For flows with nonequilibrium chemistry, the effects of the thermodynamic model on the development of flux-vector split and flux-difference split algorithms were investigated using an equilibrium model, a general nonequilibrium model, and a simplified model based on vibrational relaxation. Several numerical examples are presented, including nonequilibrium air chemistry in a high-temperature shock tube and nonequilibrium hydrogen-air chemistry in a supersonic diffuser.

  19. Computational/experimental studies of isolated, single component droplet combustion

    Science.gov (United States)

    Dryer, Frederick L.

    1993-01-01

    Isolated droplet combustion processes have been the subject of extensive experimental and theoretical investigations for nearly 40 years. The gross features of droplet burning are qualitatively embodied by simple theories and are relatively well understood. However, there remain significant aspects of droplet burning, particularly its dynamics, for which additional basic knowledge is needed for thorough interpretations and quantitative explanations of transient phenomena. Spherically-symmetric droplet combustion, which can only be approximated under conditions of both low Reynolds and Grashof numbers, represents the simplest geometrical configuration in which to study the coupled chemical/transport processes inherent within non-premixed flames. The research summarized here, concerns recent results on isolated, single component, droplet combustion under microgravity conditions, a program pursued jointly with F.A. Williams of the University of California, San Diego. The overall program involves developing and applying experimental methods to study the burning of isolated, single component droplets, in various atmospheres, primarily at atmospheric pressure and below, in both drop towers and aboard space-based platforms such as the Space Shuttle or Space Station. Both computational methods and asymptotic methods, the latter pursued mainly at UCSD, are used in developing the experimental test matrix, in analyzing results, and for extending theoretical understanding. Methanol, and the normal alkanes, n-heptane, and n-decane, have been selected as test fuels to study time-dependent droplet burning phenomena. The following sections summarizes the Princeton efforts on this program, describe work in progress, and briefly delineate future research directions.

  20. Materials by design: An experimental and computational investigation on the microanatomy arrangement of porous metallic glasses

    International Nuclear Information System (INIS)

    Sarac, Baran; Klusemann, Benjamin; Xiao, Tao; Bargmann, Swantje

    2014-01-01

    The correlation of a material’s structure with its properties is one of the important unresolved issues in materials science research. This paper discusses a novel experimental and computational approach by which the influence of the pores on the mechanical properties of bulk metallic glasses (BMGs) can be systematically and quantitatively analyzed. The experimental stage involves the fabrication of a template whose pore configurations are pre-determined by computer-aided design tools, and replication of the designed patterns with BMGs. Quasi-static mechanical characterization of these complex microstructures is conducted under uniaxial tension and in-plane compression. For the numerical simulations, a non-local gradient-enhanced continuum mechanical model is established, using thermodynamic principles and periodic boundary conditions. The combination of the experimental and numerical results has identified the importance of the pore configuration, overall porosity and diameter to the spacing ratio of the pores to attain optimized material properties

  1. EPR Studies of Spin-Spin Exchange Processes: A Physical Chemistry Experiment.

    Science.gov (United States)

    Eastman, Michael P.

    1982-01-01

    Theoretical background, experimental procedures, and analysis of experimental results are provided for an undergraduate physical chemistry experiment on electron paramagnetic resonance (EPR) linewidths. Source of line broadening observed in a spin-spin exchange process between radicals formed in aqueous solutions of potassium peroxylamine…

  2. An Iminosemiquinone-Coordinated Oxidovanadium(V) Complex: A Combined Experimental and Computational Study

    Czech Academy of Sciences Publication Activity Database

    Sarkar, P.; Mondal, M. K.; Sarmah, Amrit; Maity, S.; Mukherjee, C.

    2017-01-01

    Roč. 56, č. 14 (2017), s. 8068-8077 ISSN 0020-1669 Institutional support: RVO:61388963 Keywords : transition metal complexes * induced electron transfer * non-innocent ligands Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.857, year: 2016

  3. Molecular dynamics for irradiation driven chemistry: application to the FEBID process*

    Science.gov (United States)

    Sushko, Gennady B.; Solov'yov, Ilia A.; Solov'yov, Andrey V.

    2016-10-01

    A new molecular dynamics (MD) approach for computer simulations of irradiation driven chemical transformations of complex molecular systems is suggested. The approach is based on the fact that irradiation induced quantum transformations can often be treated as random, fast and local processes involving small molecules or molecular fragments. We advocate that the quantum transformations, such as molecular bond breaks, creation and annihilation of dangling bonds, electronic charge redistributions, changes in molecular topologies, etc., could be incorporated locally into the molecular force fields that describe the classical MD of complex molecular systems under irradiation. The proposed irradiation driven molecular dynamics (IDMD) methodology is designed for the molecular level description of the irradiation driven chemistry. The IDMD approach is implemented into the MBN Explorer software package capable to operate with a large library of classical potentials, many-body force fields and their combinations. IDMD opens a broad range of possibilities for modelling of irradiation driven modifications and chemistry of complex molecular systems ranging from radiotherapy cancer treatments to the modern technologies such as focused electron beam deposition (FEBID). As an example, the new methodology is applied for studying the irradiation driven chemistry caused by FEBID of tungsten hexacarbonyl W(CO)6 precursor molecules on a hydroxylated SiO2 surface. It is demonstrated that knowing the interaction parameters for the fragments of the molecular system arising in the course of irradiation one can reproduce reasonably well experimental observations and make predictions about the morphology and molecular composition of nanostructures that emerge on the surface during the FEBID process.

  4. Integration of Video-Based Demonstrations to Prepare Students for the Organic Chemistry Laboratory

    Science.gov (United States)

    Nadelson, Louis S.; Scaggs, Jonathan; Sheffield, Colin; McDougal, Owen M.

    2015-01-01

    Consistent, high-quality introductions to organic chemistry laboratory techniques effectively and efficiently support student learning in the organic chemistry laboratory. In this work, we developed and deployed a series of instructional videos to communicate core laboratory techniques and concepts. Using a quasi-experimental design, we tested the…

  5. Molecular computational elements encode large populations of small objects

    Science.gov (United States)

    Prasanna de Silva, A.; James, Mark R.; McKinney, Bernadine O. F.; Pears, David A.; Weir, Sheenagh M.

    2006-10-01

    Since the introduction of molecular computation, experimental molecular computational elements have grown to encompass small-scale integration, arithmetic and games, among others. However, the need for a practical application has been pressing. Here we present molecular computational identification (MCID), a demonstration that molecular logic and computation can be applied to a widely relevant issue. Examples of populations that need encoding in the microscopic world are cells in diagnostics or beads in combinatorial chemistry (tags). Taking advantage of the small size (about 1nm) and large `on/off' output ratios of molecular logic gates and using the great variety of logic types, input chemical combinations, switching thresholds and even gate arrays in addition to colours, we produce unique identifiers for members of populations of small polymer beads (about 100μm) used for synthesis of combinatorial libraries. Many millions of distinguishable tags become available. This method should be extensible to far smaller objects, with the only requirement being a `wash and watch' protocol. Our focus on converting molecular science into technology concerning analog sensors, turns to digital logic devices in the present work.

  6. Integration of computational modeling and experimental techniques to design fuel surrogates

    DEFF Research Database (Denmark)

    Choudhury, H.A.; Intikhab, S.; Kalakul, Sawitree

    2017-01-01

    performance. A simplified alternative is to develop surrogate fuels that have fewer compounds and emulate certain important desired physical properties of the target fuels. Six gasoline blends were formulated through a computer aided model based technique “Mixed Integer Non-Linear Programming” (MINLP...... Virtual Process-Product Design Laboratory (VPPD-Lab) are applied onto the defined compositions of the surrogate gasoline. The aim is to primarily verify the defined composition of gasoline by means of VPPD-Lab. ρ, η and RVP are calculated with more accuracy and constraints such as distillation curve...... and flash point on the blend design are also considered. A post-design experiment-based verification step is proposed to further improve and fine-tune the “best” selected gasoline blends following the computation work. Here, advanced experimental techniques are used to measure the RVP, ρ, η, RON...

  7. High-temperature chemistry of HCl and Cl2

    DEFF Research Database (Denmark)

    Pelucchi, Matteo; Frassoldati, Alessio; Faravelli, Tiziano

    2015-01-01

    The high temperature chlorine chemistry was updated and the inhibition mechanisms involving HCl and Cl2 were re-examined. The thermochemistry was obtained using the Active Thermochemical Tables (ATcT) approach, resulting in improved data for chlorine-containing species of interest. The HCl/Cl2....... The validation was carried out on selected experimental data from laminar flames, shock tubes and plug flow reactors. Systems containing Cl2 showed high sensitivity to Cl2 +M⇌Cl+Cl+M; the rate constant for this reaction has a significant uncertainty and there is a need for an accurate high...... chemistry discussed in the paper was based on reference and experimental measurements of rate constants available in the literature. By coupling the new HCl/Cl2 subset with the Politecnico di Milano (POLIMI) syngas mechanism a kinetic mechanism consisting of 25 species and 102 reactions was obtained...

  8. Abstracts of the 3. Brazilian Meeting on Analytical Chemistry

    International Nuclear Information System (INIS)

    1985-01-01

    Abstracts from experimental research works on analytical chemistry are presented. The following techniques were mainly used: differential pulse polarography, atomic absorption spectrophotometry, ion exchange chromatography and gamma spectroscopy. (C.L.B.) [pt

  9. The EPA CompTox Chemistry Dashboard - an online resource for environmental chemists (ACS Spring Meeting)

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program integrates advances in biology, chemistry, and computer science to help prioritize chemicals for further research based on potential human health risks. This work involves computational and data drive...

  10. The EPA Comptox Chemistry Dashboard: A Web-Based Data Integration Hub for Toxicology Data (SOT)

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program integrates advances in biology, chemistry, and computer science to help prioritize chemicals for further research based on potential human health risks. This work involves computational and data drive...

  11. Experimental and computational investigation of the NASA low-speed centrifugal compressor flow field

    Science.gov (United States)

    Hathaway, Michael D.; Chriss, Randall M.; Wood, Jerry R.; Strazisar, Anthony J.

    1993-01-01

    An experimental and computational investigation of the NASA Lewis Research Center's low-speed centrifugal compressor (LSCC) flow field was conducted using laser anemometry and Dawes' three-dimensional viscous code. The experimental configuration consisted of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational fluid dynamics analysis (CFD), and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the impeller as well as surface flow visualization along the impeller blade surfaces provided independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake that is characteristic of unshrouded centrifugal compressors.

  12. Dilution physics modeling: Dissolution/precipitation chemistry

    International Nuclear Information System (INIS)

    Onishi, Y.; Reid, H.C.; Trent, D.S.

    1995-09-01

    This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics

  13. Nuclear chemistry of transactinide elements

    Energy Technology Data Exchange (ETDEWEB)

    Nagame, Yuichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    The current status on the nuclear chemistry studies of transactinide elements is reviewed. The production of transactinides in heavy ion reactions is briefly discussed, and nuclear properties on the stability of transactinides are presented. Chemical properties of the trans-actinide elements 104, 105 and 106, and a typical experimental technique used to study these properties on an atom-at-a-time base are introduced. (author)

  14. Exploratory Experimentation and Computation

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.; Borwein, Jonathan M.

    2010-02-25

    We believe the mathematical research community is facing a great challenge to re-evaluate the role of proof in light of recent developments. On one hand, the growing power of current computer systems, of modern mathematical computing packages, and of the growing capacity to data-mine on the Internet, has provided marvelous resources to the research mathematician. On the other hand, the enormous complexity of many modern capstone results such as the Poincare conjecture, Fermat's last theorem, and the classification of finite simple groups has raised questions as to how we can better ensure the integrity of modern mathematics. Yet as the need and prospects for inductive mathematics blossom, the requirement to ensure the role of proof is properly founded remains undiminished.

  15. Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines

    National Research Council Canada - National Science Library

    Nusca, Michael J; Chen, Chiung-Chu; McQuaid, Michael J

    2007-01-01

    .... Computational fluid dynamics is employed to model the chemically reacting flow within a system's combustion chamber, and computational chemistry is employed to characterize propellant physical and reactive properties...

  16. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    International Nuclear Information System (INIS)

    To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

    2015-01-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

  17. Enhancing chemistry teaching in secondary schools: An alternative ...

    African Journals Online (AJOL)

    This study adopted the quasi-experimental research design to examine the alterative teaching methods in secondary chemistry using the cooperative instructional strategy ... Some recommendations were also made among which were that the current prevailing teaching and learning approach should be restructured.

  18. Chemistry models in the Victoria code

    International Nuclear Information System (INIS)

    Grimley, A.J. III

    1988-01-01

    The VICTORIA Computer code consists of the fission product release and chemistry models for the MELPROG severe accident analysis code. The chemistry models in VICTORIA are used to treat multi-phase interactions in four separate physical regions: fuel grains, gap/open porosity/clad, coolant/aerosols, and structure surfaces. The physical and chemical environment of each region is very different from the others and different models are required for each. The common thread in the modelling is the use of a chemical equilibrium assumption. The validity of this assumption along with a description of the various physical constraints applicable to each region will be discussed. The models that result from the assumptions and constraints will be presented along with samples of calculations in each region

  19. Foreign-Language Study Still Required for Chemistry.

    Science.gov (United States)

    Chemical and Engineering News, 1983

    1983-01-01

    Results of a survey of schools granting American Chemical Society-approved degrees indicate that most chemistry departments still require graduate students to understand a foreign language, despite much discussion in the past few years that the requirement might be outdated or that competency with computers is more relevant to chemists. (Author/JN)

  20. Quantum chemistry literature data base

    International Nuclear Information System (INIS)

    Ohno, Kimio; Morokuma, Keiji

    1982-01-01

    Ab initio computations of atomic and molecular electronic structure now appear in so many journals that it is very difficult for interested scientistics to locate proper and comprehensive references. This book is designed to help them and contains more than 2500 references to the literature published in the years 1978-1980. These have been gathered from nineteen well-known international core journals by quantum chemists themselves and the result is a thorough bibliography. Each entry is a full reference consisting of the following items: (1) authors, (2) journal name, volume, page and year, (3) compounds, (4) methods of calculation, (5) basis sets, (6) calculated properties, and (7) comments. For easy access to the references, the reader can consult the compound and author indexes. A short article on the reliability of ab initio calculations is included as an appendix; this gives a rough idea about the accuracy of the calculated results reported. As the book has been complied using the resources of a computer data base of quantum chemistry literature, it is particularly up to date and the authors will be able to provide supplements regularly. This bibliography will be an asset to large departments of chemistry and all university libraries. (orig.)

  1. Gas Phase Sulfur, Chlorine and Potassium Chemistry in Biomass Combustion

    DEFF Research Database (Denmark)

    Løj, Lusi Hindiyarti

    2007-01-01

    Gas Phase Sulfur, Chlorine and Alkali Metal Chemistry in Biomass Combustion Concern about aerosols formation, deposits, corrosion, and gaseous emissions during biomass combustion, especially straw, continues to be a driving force for investigation on S, Cl, K-containing species under combustions...... conditions. These trace species contained in the biomass structure will be released to the gas phase during combustion and contribute to the problems generated during the process. The investigation during this PhD project is done to stepwise improve the understanding in the chemistry and reduce...... the uncertainties. In the present work, the detailed kinetic model for gas phase sulfur, chlorine, alkali metal, and their interaction has been updated. The K/O/H/Cl chemistry, S chemistry, and their interaction can reasonably predict a range of experimental data. In general, understanding of the interaction...

  2. Measuring meaningful learning in the undergraduate chemistry laboratory

    Science.gov (United States)

    Galloway, Kelli R.

    The undergraduate chemistry laboratory has been an essential component in chemistry education for over a century. The literature includes reports on investigations of singular aspects laboratory learning and attempts to measure the efficacy of reformed laboratory curriculum as well as faculty goals for laboratory learning which found common goals among instructors for students to learn laboratory skills, techniques, experimental design, and to develop critical thinking skills. These findings are important for improving teaching and learning in the undergraduate chemistry laboratory, but research is needed to connect the faculty goals to student perceptions. This study was designed to explore students' ideas about learning in the undergraduate chemistry laboratory. Novak's Theory of Meaningful Learning was used as a guide for the data collection and analysis choices for this research. Novak's theory states that in order for meaningful learning to occur the cognitive, affective, and psychomotor domains must be integrated. The psychomotor domain is inherent in the chemistry laboratory, but the extent to which the cognitive and affective domains are integrated is unknown. For meaningful learning to occur in the laboratory, students must actively integrate both the cognitive domain and the affective domains into the "doing" of their laboratory work. The Meaningful Learning in the Laboratory Instrument (MLLI) was designed to measure students' cognitive and affective expectations and experiences within the context of conducting experiments in the undergraduate chemistry laboratory. Evidence for the validity and reliability of the data generated by the MLLI were collected from multiple quantitative studies: a one semester study at one university, a one semester study at 15 colleges and universities across the United States, and a longitudinal study where the MLLI was administered 6 times during two years of general and organic chemistry laboratory courses. Results from

  3. Physical-chemical processes of astrophysical interest: nitrogen chemistry

    International Nuclear Information System (INIS)

    Loison, Jean-Christophe; Hickson, Kevin; Hily-Blant, Pierre; Faure, Alexandre; Vuitton, Veronique; Bacmann, A.; Maret, Sebastien; Legal, Romane; Rist, Claire; Roncero, Octavio; Larregaray, Pascal; Hochlaf, Majdi; Senent, M. L.; Capron, Michael; Biennier, Ludovic; Carles, Sophie; Bourgalais, Jeremy; Le Picard, Sebastien; Cordier, Daniel; Guillemin, Jean-Claude; Trolez, Yann; Bertin, M.; Poderoso, H.A.M.; Michaut, X.; Jeseck, P.; Philippe, L.; Fillion, J.H.; Fayolle, E.C.; Linnartz, H.; Romanzin, C.; Oeberg, K.I.; Roueff, Evelyne; Pagani, Laurent; Padovani, Marco; Wakelam, Veronique; Honvault, Beatrice; Zvereva-Loete, Natalia; Ouk, Chanda-Malis; Scribano, Yohann; Hartmann, J.M.; Pineau des Forets, Guillaume; Hernandez, Mario; Lique, Francois; Kalugina, Yulia N.; Stoecklin, T.; Hochlaf, M.; Crespos, C.; Larregaray, P.; Martin-Gondre, L.; Petuya, R.; Quintas Sanchez, E.L.; Zanchet, Alexandre; Rodriguez-Lazcano, Yamilet; Mate, Belen

    2013-06-01

    This document contains the programme and abstracts of contributions to a workshop on nitrogen chemistry within an astrophysical perspective. These contributions have been presented in sessions: Introduction (opening lecture, experimental approaches to molecular astrophysics, theoretical approaches to astrophysics, observations in molecular astrophysics), Physical-chemical theory of the gas phase (time-dependent approach in elementary activity, statistic approach in elementary activity in the case of the N+H_2 reaction, potential energy surfaces for inelastic and reactive collisions, collision rate for N_2H"+, ortho/para selection rules in the chemistry of nitrogen hydrides, cyanides/iso-cyanides excitation in the ISM, CN excitation, radiative association with N_2H as new interstellar anion, ro-vibratory excitation of HCN) Laboratory astrophysics (measurement of reaction products in the CRESUSOL project, reactivity of the CN- anion, N_2 photo-desorption in ices, CRESU study of nitrogen chemistry, chemistry of nitrogen complex molecules), Observations and chemistry of astrophysical media (the problem of interstellar nitrogen fractioning, abundance of N_2 in proto-stellar cores, HNC in Titan atmosphere and nitrogen-related mechanisms in hot Jupiters, HCN and HNC in dark clouds or how theoretical modelling helps in interpreting observations, nitrogen chemistry in cold clouds, deuteration of nitrogen hydrides, nitrogen in interstellar ices, biochemical molecules on Titan, coupling between excitation and chemistry, radiative transfer of nitrogen hydrides, ortho/para chemistry of nitrogen hydrides), Physical-chemical theory of gas-grain interactions (nitrogen reactivity on surfaces, IR spectra of ices of NH_3 and NH_3/N_2 mixtures)

  4. Probabilistic performance estimators for computational chemistry methods: The empirical cumulative distribution function of absolute errors

    Science.gov (United States)

    Pernot, Pascal; Savin, Andreas

    2018-06-01

    Benchmarking studies in computational chemistry use reference datasets to assess the accuracy of a method through error statistics. The commonly used error statistics, such as the mean signed and mean unsigned errors, do not inform end-users on the expected amplitude of prediction errors attached to these methods. We show that, the distributions of model errors being neither normal nor zero-centered, these error statistics cannot be used to infer prediction error probabilities. To overcome this limitation, we advocate for the use of more informative statistics, based on the empirical cumulative distribution function of unsigned errors, namely, (1) the probability for a new calculation to have an absolute error below a chosen threshold and (2) the maximal amplitude of errors one can expect with a chosen high confidence level. Those statistics are also shown to be well suited for benchmarking and ranking studies. Moreover, the standard error on all benchmarking statistics depends on the size of the reference dataset. Systematic publication of these standard errors would be very helpful to assess the statistical reliability of benchmarking conclusions.

  5. Progress report, Chemistry and Materials Division, July 1 to September 30, 1975

    International Nuclear Information System (INIS)

    1975-10-01

    Studies of x-rays produced by ion-penetration confirming the view that target and host atoms participate in two-collision sequences are reported along with related studies of K x-rays observed when projectile ions are lighter than target atoms. The latter observation was not expected on the basis of current theory and is the first experimental evidence for radial coupling in asymmetric heavy ion collisions. A computer simulation model yielding good agreement with experimental observations on the planar dechanneling process is described. Research on the chemistry of alkali metals in amine solutions showing improved accord between results of pulse radiolysis, optical spectroscopy and electron spin resonance is described. Preliminary measurements of kinetic isotope effects in the reaction between methanol and bromine in the presence of weak visible light are discussed. Studies on the influence of adsorbed gases on electronic energy levels of atoms in the surface layers of catalytically active metals are summarized. Oxidation studies on Zr 3 Al and crystal bar zirconium are also reported. (O.T.)

  6. Experimental realization of quantum cheque using a five-qubit quantum computer

    Science.gov (United States)

    Behera, Bikash K.; Banerjee, Anindita; Panigrahi, Prasanta K.

    2017-12-01

    Quantum cheques could be a forgery-free way to make transaction in a quantum networked banking system with perfect security against any no-signalling adversary. Here, we demonstrate the implementation of quantum cheque, proposed by Moulick and Panigrahi (Quantum Inf Process 15:2475-2486, 2016), using the five-qubit IBM quantum computer. Appropriate single qubit, CNOT and Fredkin gates are used in an optimized configuration. The accuracy of implementation is checked and verified through quantum state tomography by comparing results from the theoretical and experimental density matrices.

  7. A computationally inexpensive CFD approach for small-scale biomass burners equipped with enhanced air staging

    International Nuclear Information System (INIS)

    Buchmayr, M.; Gruber, J.; Hargassner, M.; Hochenauer, C.

    2016-01-01

    Highlights: • Time efficient CFD model to predict biomass boiler performance. • Boundary conditions for numerical modeling are provided by measurements. • Tars in the product from primary combustion was considered. • Simulation results were validated by experiments on a real-scale reactor. • Very good accordance between experimental and simulation results. - Abstract: Computational Fluid Dynamics (CFD) is an upcoming technique for optimization and as a part of the design process of biomass combustion systems. An accurate simulation of biomass combustion can only be provided with high computational effort so far. This work presents an accurate, time efficient CFD approach for small-scale biomass combustion systems equipped with enhanced air staging. The model can handle the high amount of biomass tars in the primary combustion product at very low primary air ratios. Gas-phase combustion in the freeboard was performed by the Steady Flamelet Model (SFM) together with a detailed heptane combustion mechanism. The advantage of the SFM is that complex combustion chemistry can be taken into account at low computational effort because only two additional transport equations have to be solved to describe the chemistry in the reacting flow. Boundary conditions for primary combustion product composition were obtained from the fuel bed by experiments. The fuel bed data were used as fuel inlet boundary condition for the gas-phase combustion model. The numerical and experimental investigations were performed for different operating conditions and varying wood-chip moisture on a special designed real-scale reactor. The numerical predictions were validated with experimental results and a very good agreement was found. With the presented approach accurate results can be provided within 24 h using a standard Central Processing Unit (CPU) consisting of six cores. Case studies e.g. for combustion geometry improvement can be realized effectively due to the short calculation

  8. Characterization of iminothiosulfine-type ions [HNCS 2] rad +/ rad - and their neutral counterparts by mass spectrometry and computational chemistry

    Science.gov (United States)

    Vivekananda, S.; Raghunath, P.; Bhanuprakash, K.; Srinivas, R.; Trikoupis, Moschoula A.; Terlouw, Johan K.

    2000-12-01

    Electron ionization of rhodanine yields iminothiosulfine ions H- N C- S- Srad + , 1brad + , which readily communicate with the higher energy cyclic isomer H- N CS2rad + , 1arad + . CBS-QB3 and G AUSSIAN-2 model chemistries predict that one electron reduction reverses the stability order but that the (singlet) neutrals remain connected via a negligible energy barrier. Neutralization-reionization (NR) experiments demonstrate that singlet 1a and its heterocumulene isomer 1b are stable species in the gas-phase. However, the co-generated triplet species readily dissociate into 3S2rad + + HNC. Confirmatory experimental evidence comes from charge reversal (CR) and NR experiments on the cyclic anion H- N CS2rad - , 1arad - .

  9. Contribution of water chemistry and fish condition to otolith chemistry: comparisons across salinity environments.

    Science.gov (United States)

    Izzo, C; Doubleday, Z A; Schultz, A G; Woodcock, S H; Gillanders, B M

    2015-06-01

    This study quantified the per cent contribution of water chemistry to otolith chemistry using enriched stable isotopes of strontium ((86) Sr) and barium ((137) Ba). Euryhaline barramundi Lates calcarifer, were reared in marine (salinity 40), estuarine (salinity 20) and freshwater (salinity 0) under different temperature treatments. To calculate the contribution of water to Sr and Ba in otoliths, enriched isotopes in the tank water and otoliths were quantified and fitted to isotope mixing models. Fulton's K and RNA:DNA were also measured to explore the influence of fish condition on sources of element uptake. Water was the predominant source of otolith Sr (between 65 and 99%) and Ba (between 64 and 89%) in all treatments, but contributions varied with temperature (for Ba), or interactively with temperature and salinity (for Sr). Fish condition indices were affected independently by the experimental rearing conditions, as RNA:DNA differed significantly among salinity treatments and Fulton's K was significantly different between temperature treatments. Regression analyses did not detect relations between fish condition and per cent contribution values. General linear models indicated that contributions from water chemistry to otolith chemistry were primarily influenced by temperature and secondly by fish condition, with a relatively minor influence of salinity. These results further the understanding of factors that affect otolith element uptake, highlighting the necessity to consider the influence of environment and fish condition when interpreting otolith element data to reconstruct the environmental histories of fish. © 2015 The Fisheries Society of the British Isles.

  10.  The application of computational chemistry to lignin

    Science.gov (United States)

    Thomas Elder; Laura Berstis; Nele Sophie Zwirchmayr; Gregg T. Beckham; Michael F. Crowley

    2017-01-01

    Computational chemical methods have become an important technique in the examination of the structure and reactivity of lignin. The calculations can be based either on classical or quantum mechanics, with concomitant differences in computational intensity and size restrictions. The current paper will concentrate on results developed from the latter type of calculations...

  11. Effectiveness of Analogy Instructional Strategy on Undergraduate Student's Acquisition of Organic Chemistry Concepts in Mutah University, Jordan

    Science.gov (United States)

    Samara, Nawaf Ahmad Hasan

    2016-01-01

    This study aimed at investigating the effectiveness of analogy instructional strategy on undergraduate students' acquisition of organic chemistry concepts in Mutah University, Jordan. A quasi-experimental design was used in the study; Participants were 97 students who enrolled in organic chemistry course at the department of chemistry during the…

  12. Ensuring Sustainability of Tomorrow through Green Chemistry Integrated with Sustainable Development Concepts (SDCS)

    Science.gov (United States)

    Karpudewan, Mageswary; Ismail, Zurida; Roth, Wolff-Michael

    2012-01-01

    The purpose of this article is to describe a best practice: an approach to teaching chemistry that our quantitative research has shown to produce large differences between experimental and control groups in terms of achievement, pro-environmental attitudes, values, and motivation. Our interest in teaching chemistry by focusing on sustainable…

  13. Introducing Undergraduates to Research Using a Suzuki-Miyaura Cross-Coupling Organic Chemistry Miniproject

    Science.gov (United States)

    Oliveira, Deyvid G. M.; Rosa, Clarissa H.; Vargas, Bruna P.; Rosa, Diego S.; Silveira, Ma´rcia V.; de Moura, Neusa F.; Rosa, Gilber R.

    2015-01-01

    A five-week miniproject is described for an upper-division experimental organic chemistry course. The activities include synthesis of a phenylboronic acid via a Grignard reaction and its use in a Suzuki-Miyaura cross-coupling reaction. Technical skills and concepts normally presented in practical organic chemistry courses are covered, including…

  14. MADNESS applied to density functional theory in chemistry and nuclear physics

    International Nuclear Information System (INIS)

    Fann, G I; Harrison, R J; Beylkin, G; Jia, J; Hartman-Baker, R; Shelton, W A; Sugiki, S

    2007-01-01

    We describe some recent mathematical results in constructing computational methods that lead to the development of fast and accurate multiresolution numerical methods for solving quantum chemistry and nuclear physics problems based on Density Functional Theory (DFT). Using low separation rank representations of functions and operators in conjunction with representations in multiwavelet bases, we developed a multiscale solution method for integral and differential equations and integral transforms. The Poisson equation, the Schrodinger equation, and the projector on the divergence free functions provide important examples with a wide range of applications in computational chemistry, nuclear physics, computational electromagnetic and fluid dynamics. We have implemented this approach along with adaptive representations of operators and functions in the multiwavelet basis and low separation rank (LSR) approximation of operators and functions. These methods have been realized and implemented in a software package called Multiresolution Adaptive Numerical Evaluation for Scientific Simulation (MADNESS)

  15. Numerical verification of equilibrium chemistry software within nuclear fuel performance codes

    International Nuclear Information System (INIS)

    Piro, M.H.; Lewis, B.J.; Thompson, W.T.; Simunovic, S.; Besmann, T.M.

    2010-01-01

    A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing transport source terms, material properties, and boundary conditions in heat and mass transport modules. Consequently, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method called the Gibbs Criteria is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes. (author)

  16. Transactinide nuclear chemistry at JAERI

    International Nuclear Information System (INIS)

    Nagame, Y.; Haba, H.; Tsukada, K.

    2002-01-01

    Nuclear chemistry study of trans actinide elements in Japan is currently being in progress at JAERI (Japan Atomic Energy Research Institute). We have developed new experimental apparatuses: a beam-line safety system for the usage of the gas-jet coupled radioactive 248 Cm target chamber, a rotating wheel catcher apparatus for the measurement of α and spontaneous fission decay of the transactinides, MANON (Measurement system for Alpha particles and spontaneous fission events ON line), and an automated rapid chemical separation apparatus based on the high performance liquid chromatography, AIDA (Automated Ion exchange separation system coupled with the Detection apparatus for Alpha spectroscopy). The transactinide nuclei, 261 Rf and 262 Db, have been successfully produced via the reactions of 248 Cm( 18 O,5n) and 248 Cm( 19 F,5n), respectively, and the excitation functions for each reaction have been measured to evaluate the optimum irradiation condition for the production of these nuclei. The maximum cross sections in each reaction were 13 nb at the 18 O beam energy of 94-MeV and 1.5 Nb at the 103-MeV 19 F beam energy. On-line ion exchange experiments of Rf together with the lighter homologues Zr and Hf in the HCl, HNO 3 and HF solutions with AIDA have been carried out, and the results clearly show that the behavior of Rf is typical of the group-4 element. Relativistic molecular orbital calculations of the chloride and nitrate complexes of tetravalent Rf are also being performed to gain an understanding of the complex chemistry. Prospects and some recent experimental results for the nuclear chemistry study of the transactinide elements at JAERI are discussed. (author)

  17. Evaluated kinetic and photochemical data for atmospheric chemistry: Supplement VIII, halogen species evaluation for atmospheric chemistry

    International Nuclear Information System (INIS)

    Atkinson, R.; Baulch, D.L.; Cox, R.A.; Hampson, R.F. Jr.; Kerr, J.A.; Rossi, M.J.; Troe, J.

    2000-01-01

    This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997); 28, 191 (1999)]. The present evaluation is limited to the inorganic halogen family of atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 102 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations that model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available values of enthalpies of formation of the reactant and product species

  18. Chemistry and physics

    International Nuclear Information System (INIS)

    Broerse, J.J.; Barendsen, G.W.; Kal, H.B.; Kogel, A.J. van der

    1983-01-01

    This book contains the extended abstracts of the contributions of the poster workshop sessions on chemistry and physics of the 7th international congress of radiation research. They cover the following main topics: primary processes in radiation physics and chemistry, general chemistry in radiation chemistry, DNA and model systems in radiation chemistry, molecules of biological interest in radiation chemistry, techniques in radiation chemistry, hot atom chemistry. refs.; figs.; tabs

  19. TEXTBOOK ANALYSIS IN THE SERVICE OF CHEMISTRY TEACHING

    Directory of Open Access Journals (Sweden)

    Aija Ahtineva

    2005-06-01

    Full Text Available The authors of textbooks have their own visions of contents and teaching methods, which should lead to a high level of scientific thinking. However, the textbook alone does not guarantee good results because the personal and social relationships between the teacher and students have a major influence on teaching and learning. Therefore, the teacher’s study of the textbook before teaching facilitates the teaching process. This paper suggests one method of textbook analysis. In the analysis, one upper secondary level course of chemistry instruction involved the use of a learning strategy: classification of the central concepts and a classification of activities based on task difficulty. The study also attempted to find out the goodness of fit between the national curriculum and the textbook chemistry course. The national objectives concerned the content of knowledge, social significance, emphasis on experimental chemistry, and inspiring students for further study. The majority of the textbook tasks fall into higher order categories characterized by knowledge structures assuming application of knowledge or making inferences. Good textbook activities also have social significance, and a number of experimental tasks are included. The textbook quality is further enhanced by up-to-date content. All of the above qualities are related to high study motivation.

  20. Open chemistry: RESTful web APIs, JSON, NWChem and the modern web application.

    Science.gov (United States)

    Hanwell, Marcus D; de Jong, Wibe A; Harris, Christopher J

    2017-10-30

    An end-to-end platform for chemical science research has been developed that integrates data from computational and experimental approaches through a modern web-based interface. The platform offers an interactive visualization and analytics environment that functions well on mobile, laptop and desktop devices. It offers pragmatic solutions to ensure that large and complex data sets are more accessible. Existing desktop applications/frameworks were extended to integrate with high-performance computing resources, and offer command-line tools to automate interaction-connecting distributed teams to this software platform on their own terms. The platform was developed openly, and all source code hosted on the GitHub platform with automated deployment possible using Ansible coupled with standard Ubuntu-based machine images deployed to cloud machines. The platform is designed to enable teams to reap the benefits of the connected web-going beyond what conventional search and analytics platforms offer in this area. It also has the goal of offering federated instances, that can be customized to the sites/research performed. Data gets stored using JSON, extending upon previous approaches using XML, building structures that support computational chemistry calculations. These structures were developed to make it easy to process data across different languages, and send data to a JavaScript-based web client.