WorldWideScience

Sample records for theoretical studies

  1. Theoretical studies of chemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, G.C. [Argonne National Laboratory, IL (United States)

    1993-12-01

    This collaborative program with the Theoretical Chemistry Group at Argonne involves theoretical studies of gas phase chemical reactions and related energy transfer and photodissociation processes. Many of the reactions studied are of direct relevance to combustion; others are selected they provide important examples of special dynamical processes, or are of relevance to experimental measurements. Both classical trajectory and quantum reactive scattering methods are used for these studies, and the types of information determined range from thermal rate constants to state to state differential cross sections.

  2. Theoretical Semi-Empirical AM1 studies of Schiff Bases

    International Nuclear Information System (INIS)

    Arora, K.; Burman, K.

    2005-01-01

    The present communication reports the theoretical semi-empirical studies of schiff bases of 2-amino pyridine along with their comparison with their parent compounds. Theoretical studies reveal that it is the azomethine group, in the schiff bases under study, that acts as site for coordination to metals as it is reported by many coordination chemists. (author)

  3. A combined experimental and theoretical study

    Indian Academy of Sciences (India)

    A combined theoretical and experimental study was also performed, which demonstrated that the clus- ters 1–3 with ... silica gel TLC plates (MERCK TLC Plates). The NMR .... tronic μ3-Se and maintains the same number of clus- ter valance ...

  4. Diffusion in liquids a theoretical and experimental study

    CERN Document Server

    Tyrrell, H J V

    1984-01-01

    Diffusion in Liquids: A Theoretical and Experimental Study aims to discuss the principles, applications, and advances in the field of diffusion, thermal diffusion, and thermal conduction in liquid systems. The book covers topics such as the principles of non-equilibrium thermodynamics; diffusion in binary and multicompetent systems; and experimental methods of studying diffusion processes in liquids. Also covered in the book are topics such as the theoretical interpretations of diffusion coefficients; hydrodynamic and kinetic theories; and diffusion in electrolyte systems. The text is recommen

  5. Surfactants, interfaces and pores : a theoretical study

    NARCIS (Netherlands)

    Huinink, H.

    1998-01-01

    The aim of this study was to investigate the behavior of surfactants in porous media by theoretical means. The influence of curvature of a surface on the adsorption has been studied with a mean field lattice (MFL) model, as developed by Scheutjens and Fleer. An analytical theory has been

  6. Theoretical Studies of Small-System Thermodynamics in Energetic Materials

    Science.gov (United States)

    2016-01-06

    SECURITY CLASSIFICATION OF: This is a comprehensive theoretical research program to investigate the fundamental principles of small-system thermodynamics ...a.k.a. nanothermodynamics). The proposed work is motivated by our desire to better understand the fundamental dynamics and thermodynamics of...for Public Release; Distribution Unlimited Final Report: Theoretical Studies of Small-System Thermodynamics in Energetic Materials The views, opinions

  7. EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST ...

    African Journals Online (AJOL)

    EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST BEAM-SLAB. CONSTRUCTION. Girma Zerayohannes and Adil Zekaria. Department of Civil Engineering. Addis Ababa University. ABSTRACT. The use of partially precast beam elements ivith shear connectors in slab construction relieves the requirement of ...

  8. Theoretical studies of combustion dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.M. [Emory Univ., Atlanta, GA (United States)

    1993-12-01

    The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.

  9. Sibutramine characterization and solubility, a theoretical study

    Science.gov (United States)

    Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René

    2013-04-01

    Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.

  10. Theoretical study for solar air pretreatment collector/regenerator

    Energy Technology Data Exchange (ETDEWEB)

    Peng Donggen; Zhang Xiaosong; Yin Yonggao [School of Energy and Environment, Southeast Univ., Nanjing (China)

    2008-07-01

    A new liquid regeneration equipment - solar air pretreatment collector/regenerator for liquid desiccant cooling system is put forward in this paper, which is preferable to solution regeneration in hot and moist climate in South China. The equipment can achieve liquid regeneration in lower temperature. When the solution and the air are in ''match'' state in collector/ regenerator, a match air to salt mass ratio ASMR* is found by theoretical study in which there is the largest theoretical storage capacity SC{sub max}. After two new concepts of the effective solution proportion (EPS) and the effective storage capacity (ESC) are defined, it is found by theoretical calculation that when ESP drops from 100% to 67%, ESC raises lowly, not drops and liquid outlet concentration C{sub str} {sub sol} increases from 40% to 49% in which its increment totals to 90%. All these data explain fully that air pretreatment liquid regeneration equipment enables to improve the performance of liquid desiccant cooling system. (orig.)

  11. Theoretical and simulation studies of seeding methods

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, Claudio [Univ. of California, Los Angeles, CA (United States)

    2017-12-11

    We report the theoretical and experimental studies done with the support of DOE-Grant DE-SC0009983 to increase an X-ray FEL peak power from the present level of 20 to 40 GW to one or more TW by seeding, undulator tapering and using the new concept of the Double Bunch FEL.

  12. Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental

    2013-02-15

    In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)

  13. For a new dialogue between theoretical and empirical studies in evo-devo

    Directory of Open Access Journals (Sweden)

    Giuseppe eFusco

    2015-08-01

    Full Text Available Despite its potentially broad scope, current evo-devo research is largely dominated by empirical developmental studies, whereas comparably little role is played by theoretical research. I argue that this represents an obstacle to a wider appreciation of evo-devo and its integration within a more comprehensive evolutionary theory, and that this situation is causally linked to a limited exchange between theoretical and experimental studies in evo-devo. I discuss some features of current theoretical work in evo-devo, highlighting some possibly concurring impediments to an effective dialogue with experimental studies. Finally, I advance two suggestions for enhancing fruitful cross-fertilization between theoretical and empirical studies in evo-devo: i to broaden the scope of evo-devo beyond its current conceptualization, teaming up with other variational approaches to the study of evolution, and ii to develop more effective forms of scientific interaction and communication.

  14. THEORETICAL ASPECTS OF FILMMUSIC STUDY

    Directory of Open Access Journals (Sweden)

    Egorova Tatiana K.

    2014-04-01

    Full Text Available In this article, author analyzes the theoretical aspects of the film music study taking into account with modern realities in the development of world film-process and attempts to its scientific understanding. Need for innovation in this area is long overdue, because the existing on this topic nonfiction no longer meets the new aesthetic and art-practical achievements and innovations in the film music development at the XXI century. Related to the phenomenon of music in screen arts a number of new terms and concepts require a certain adjustment as well. Their range of action is not yet fully defined. Author of the article offered her version of their content-semantic interpretation (largely experimental designed to promote new research methods for the film music study.

  15. Theoretical studies on core-level spectra of solids

    International Nuclear Information System (INIS)

    Kotani, Akio

    1995-01-01

    I present a review on theoretical studies of core-level spectra (CLS) in solids. In CLS, the dynamical response of outer electrons to a core hole is reflected through the screening of core hole potential. Impurity Anderson model (IAM) or cluster model is successfully applied to the analysis of X-ray photoemission spectra (XPS) and X-ray absorption spectra (XAS) in f and d electron systems, where the f and d electron states are hybridized with the other valence or conduction electron states. The effect of the core-hole potential in the final state of XPS and XAS plays an important role, as well as the solid state hybridization and intra-atomic multiplet coupling effects. As typical examples, the calculated results for XPS of rare-earth compounds and transition metal compounds are shown, and some discussions are given. As a subject of remarkable progress with high brightness synchrotron radiation sources, I discuss some theoretical aspects of X-ray emission spectra (XES) and their resonant enhancement at the X-ray absorption threshold. Some experimental data and their theoretical analysis are also given. (author)

  16. Theoretical and Methodological Perspectives on Designing Video Studies of Interaction

    Directory of Open Access Journals (Sweden)

    Anna-Lena Rostvall

    2005-12-01

    Full Text Available In this article the authors discuss the theoretical basis for the methodological decisions made during the course of a Swedish research project on interaction and learning. The purpose is to discuss how different theories are applied at separate levels of the study. The study is structured on three levels, with separate sets of research questions and theoretical concepts. The levels reflect a close-up description, a systematic analysis, and an interpretation of how teachers and students act and interact. The data consist of 12 hours of video-recorded and transcribed music lessons from high school and college. Through a multidisciplinary theoretical framework, the general understanding of teaching and learning in terms of interaction can be widened. The authors also present a software tool developed to facilitate the processes of transcription and analysis of the video data.

  17. An in-depth analysis of theoretical frameworks for the study of care coordination

    Directory of Open Access Journals (Sweden)

    Sabine Van Houdt

    2013-06-01

    Full Text Available Introduction: Complex chronic conditions often require long-term care from various healthcare professionals. Thus, maintaining quality care requires care coordination. Concepts for the study of care coordination require clarification to develop, study and evaluate coordination strategies. In 2007, the Agency for Healthcare Research and Quality defined care coordination and proposed five theoretical frameworks for exploring care coordination. This study aimed to update current theoretical frameworks and clarify key concepts related to care coordination. Methods: We performed a literature review to update existing theoretical frameworks. An in-depth analysis of these theoretical frameworks was conducted to formulate key concepts related to care coordination.Results: Our literature review found seven previously unidentified theoretical frameworks for studying care coordination. The in-depth analysis identified fourteen key concepts that the theoretical frameworks addressed. These were ‘external factors’, ‘structure’, ‘tasks characteristics’, ‘cultural factors’, ‘knowledge and technology’, ‘need for coordination’, ‘administrative operational processes’, ‘exchange of information’, ‘goals’, ‘roles’, ‘quality of relationship’, ‘patient outcome’, ‘team outcome’, and ‘(interorganizational outcome’.Conclusion: These 14 interrelated key concepts provide a base to develop or choose a framework for studying care coordination. The relational coordination theory and the multi-level framework are interesting as these are the most comprehensive.

  18. Theoretical study of nuclear physics with strangeness at Nankai University

    International Nuclear Information System (INIS)

    Ning Pingzhi

    2007-01-01

    Theoretical study of nuclear physics with strangeness from the nuclear physics group at Nankai university is briefly introduced. Theoretical calculations on hyperon mean free paths in nuclear medium have been done. The other 4 topics in the area of strangeness nuclear physics are the effect of different baryon impurities in nucleus, the heavy flavored baryon hypernuclei, the eta-mesons in nuclear matter and the properties of kaonic nuclei. (authors)

  19. Theoretical and experimental study of fenofibrate and simvastatin

    Science.gov (United States)

    Nicolás Vázquez, Inés; Rodríguez-Núñez, Jesús Rubén; Peña-Caballero, Vicente; Ruvalcaba, Rene Miranda; Aceves-Hernandez, Juan Manuel

    2017-12-01

    Fenofibrate, an oral fibrate lipid lowering agent, and simvastatin, which reduces plasma levels of low-density lipoprotein cholesterol, are active pharmaceutical ingredients (APIs), currently in the market. We characterized these APIs by thermal analysis and conducted X-ray powder diffraction techniques. Studies should be carried out in the formulation stage before the final composition of a polypill may be established. Thus, it was found in thermochemical studies that both compounds present no chemical interactions in an equimolar mixture of solid samples at room temperature. Theoretical studies were employed to determine possible interactions between fenofibrate and simvastatin. A very weak intramolecular hydrogen bond is formed between the hydroxyl group (O5H5) of the simvastatin with chlorine and carbonyl group (C11O4, C1O2) of the fenofibrate molecule. These weak energy hydrogen bonds have no effect on the chemical stability of the compounds studied. The results were obtained using Density Functional Theory methods; particularly the BPE1BPE and B3LYP functional and 6-31++G** basis set. The values of energy show good approximation when are compared with similar calculations previously reported. Infrared spectra of monomers and dimers were obtained via theoretical calculations.

  20. Theoretical studies in nuclear reactions and nuclear structure

    International Nuclear Information System (INIS)

    Wallace, S.J.

    1991-05-01

    This report discusses topics in the following areas: Hadronic structure; hadrons in nuclei; hot hadronic matter; relativistic nuclear physics and NN interaction; leptonic emissions from high-Z heavy ion collisions; theoretical studies of heavy ion dynamics; nuclear pre-equilibrium reactions; classical chaotic dynamics and nuclear structure; and, theory of nuclear fission

  1. Theoretical Studies on Photoionization Cross Sections of Solid Gold

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Sun Weiguo; Cheng Yansong

    2005-01-01

    Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoionization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part ε' and the imaginary part ε'' of the complex dielectric constant ε, and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.

  2. Theoretical study of near-threshold electron-molecule scattering

    International Nuclear Information System (INIS)

    Morrison, M.A.

    1989-01-01

    We have been engaged in carrying out a foundation study on problems pertaining to near-threshold nuclear excitations in e-H 2 scattering. The primary goals of this study are: to investigate the severity and nature of the anticipated breakdown of the adiabatic-nuclei (AN) approximation, first for rotation only (in the rigid-rotator approximation), and then for vibration; to determine a data base of accurate ab initio cross sections for this important system; to implement and test accurate, computationally-tractable model potentials for exchange and polarization effects; and to begin the exploration of alternative scattering theories for near-threshold collisions. This study has provided a well-defined theoretical context for our future investigations. Second, it has enabled us to identify and quantify several serious problems in the theory of near-threshold electron-molecule scattering that demand attention. And finally, it has led to the development of some of the theoretical and computational apparatus that will form the foundation of future work. In this report, we shall review our progress to date, emphasizing work completed during the current contract year. 17 refs., 5 figs., 1 tab

  3. Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Wesley D. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry; Schaefer, III, Henry F. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry

    2015-11-14

    This is the final report of the theoretical studies of elementary hydrocarbon species and their reactions. Part A has a bibliography of publications supported by DOE from 2010 to 2016 and Part B goes into recent research highlights.

  4. Theoretical modelling of semiconductor surfaces microscopic studies of electrons and photons

    CERN Document Server

    Srivastava, G P

    1999-01-01

    The state-of-the-art theoretical studies of ground state properties, electronic states and atomic vibrations for bulk semiconductors and their surfaces by the application of the pseudopotential method are discussed. Studies of bulk and surface phonon modes have been extended by the application of the phenomenological bond charge model. The coverage of the material, especially of the rapidly growing and technologically important topics of surface reconstruction and chemisorption, is up-to-date and beyond what is currently available in book form. Although theoretical in nature, the book provides

  5. Theoretical nuclear reaction and structure studies using hyperons and photons

    International Nuclear Information System (INIS)

    Cotanch, S.R.

    1991-01-01

    This report details research progress and results obtained during the 12 month period from January 1991 through 31 December 1991. The research project, entitled ''Theoretical Nuclear Reaction and Structure Studies Using Hyperons and Photons,'' is supported by grant DE-FG05-88ER40461 between North Carolina State University and the United States Department of Energy. In compliance with grant requirements the Principal Investigator, Professor Stephen R. Cotanch, has conducted a research program addressing theoretical investigations of reactions involving hyperons and photons. The new, significant research results are briefly summarized in the following sections

  6. Theoretical study of n-alkane adsorption on metal surfaces

    DEFF Research Database (Denmark)

    Morikawa, Yoshitada; Ishii, Hisao; Seki, Kazuhiko

    2004-01-01

    The interaction between n-alkane and metal surfaces has been studied by means of density-functional theoretical calculations within a generalized gradient approximation (GGA). We demonstrate that although the GGA cannot reproduce the physisorption energy well, our calculations can reproduce the e...

  7. Theoretical pluralism in psychoanalytic case studies.

    Science.gov (United States)

    Willemsen, Jochem; Cornelis, Shana; Geerardyn, Filip M; Desmet, Mattias; Meganck, Reitske; Inslegers, Ruth; Cauwe, Joachim M B D

    2015-01-01

    The aim of this study is to provide an overview of the scientific activity of different psychoanalytic schools of thought in terms of the content and production of case studies published on ISI Web of Knowledge. Between March 2013 and November 2013, we contacted all case study authors included in the online archive of psychoanalytic and psychodynamic case studies (www.singlecasearchive.com) to inquire about their psychoanalytic orientation during their work with the patient. The response rate for this study was 45%. It appears that the two oldest psychoanalytic schools, Object-relations psychoanalysis and Ego psychology or "Classical psychoanalysis" dominate the literature of published case studies. However, most authors stated that they feel attached to two or more psychoanalytic schools of thought. This confirms that the theoretical pluralism in psychoanalysis stretches to the field of single case studies. The single case studies of each psychoanalytic school are described separately in terms of methodology, patient, therapist, or treatment features. We conclude that published case studies features are fairly similar across different psychoanalytic schools. The results of this study are not representative of all psychoanalytic schools, as some do not publish their work in ISI ranked journals.

  8. Theoretical pluralism in psychoanalytic case studies

    Science.gov (United States)

    Willemsen, Jochem; Cornelis, Shana; Geerardyn, Filip M.; Desmet, Mattias; Meganck, Reitske; Inslegers, Ruth; Cauwe, Joachim M. B. D.

    2015-01-01

    The aim of this study is to provide an overview of the scientific activity of different psychoanalytic schools of thought in terms of the content and production of case studies published on ISI Web of Knowledge. Between March 2013 and November 2013, we contacted all case study authors included in the online archive of psychoanalytic and psychodynamic case studies (www.singlecasearchive.com) to inquire about their psychoanalytic orientation during their work with the patient. The response rate for this study was 45%. It appears that the two oldest psychoanalytic schools, Object-relations psychoanalysis and Ego psychology or “Classical psychoanalysis” dominate the literature of published case studies. However, most authors stated that they feel attached to two or more psychoanalytic schools of thought. This confirms that the theoretical pluralism in psychoanalysis stretches to the field of single case studies. The single case studies of each psychoanalytic school are described separately in terms of methodology, patient, therapist, or treatment features. We conclude that published case studies features are fairly similar across different psychoanalytic schools. The results of this study are not representative of all psychoanalytic schools, as some do not publish their work in ISI ranked journals. PMID:26483725

  9. Theoretical study of rock mass investigation efficiency

    International Nuclear Information System (INIS)

    Holmen, Johan G.; Outters, Nils

    2002-05-01

    The study concerns a mathematical modelling of a fractured rock mass and its investigations by use of theoretical boreholes and rock surfaces, with the purpose of analysing the efficiency (precision) of such investigations and determine the amount of investigations necessary to obtain reliable estimations of the structural-geological parameters of the studied rock mass. The study is not about estimating suitable sample sizes to be used in site investigations.The purpose of the study is to analyse the amount of information necessary for deriving estimates of the geological parameters studied, within defined confidence intervals and confidence level In other words, how the confidence in models of the rock mass (considering a selected number of parameters) will change with amount of information collected form boreholes and surfaces. The study is limited to a selected number of geometrical structural-geological parameters: Fracture orientation: mean direction and dispersion (Fisher Kappa and SRI). Different measures of fracture density (P10, P21 and P32). Fracture trace-length and strike distributions as seen on horizontal windows. A numerical Discrete Fracture Network (DFN) was used for representation of a fractured rock mass. The DFN-model was primarily based on the properties of an actual fracture network investigated at the Aespoe Hard Rock Laboratory. The rock mass studied (DFN-model) contained three different fracture sets with different orientations and fracture densities. The rock unit studied was statistically homogeneous. The study includes a limited sensitivity analysis of the properties of the DFN-model. The study is a theoretical and computer-based comparison between samples of fracture properties of a theoretical rock unit and the known true properties of the same unit. The samples are derived from numerically generated boreholes and surfaces that intersect the DFN-network. Two different boreholes are analysed; a vertical borehole and a borehole that is

  10. Preparation of theoretical scanning tunneling microscope images of adsorbed molecules: a theoretical study of benzene on the Cu(110) surface

    International Nuclear Information System (INIS)

    Shapter, J.G.; Rogers, B.L.; Ford, M.J.

    2003-01-01

    Full text: Since its development in 1982, the Scanning Tunneling Microscope (STM) has developed into a powerful tool for the study of surfaces and adsorbates. However, the utility of the technique can be further enhanced through the development of techniques for generating theoretical STM images. This is particularly true when studying molecules adsorbed on a substrate, as the results are often interpreted superficially due to an inadequate understanding of the orbital overlap probed in the experiment. A method of preparing theoretical scanning tunneling microscope (STM) images using comparatively inexpensive desktop computers and the commercially available CRYSTAL98 package is presented through a study of benzene adsorbed on the Cu(110) surface. Density Functional Theory (DFT) and Hartree-Fock (HF) methods are used to model clean Cu(110) slabs of various thicknesses and to simulate the adsorption of benzene onto these slabs. Eight possible orientations of benzene on the Cu(110) surface are proposed, and the optimum orientation according to the calculations is presented. Theoretical STM images of the Cu(110) surface and benzene adsorbed on the Cu(110) surface are compared with experimental STM images of the system from a published study. Significant differences are observed and are examined in detail

  11. Theoretical studies on aerosol agglomeration processes

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use

    1997-12-31

    In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

  12. Theoretical studies on aerosol agglomeration processes

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, K E.J. [VTT Energy, Espoo (Finland). Energy Use

    1998-12-31

    In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

  13. Theoretical framework to study exercise motivation for breast cancer risk reduction.

    Science.gov (United States)

    Wood, Maureen E

    2008-01-01

    To identify an appropriate theoretical framework to study exercise motivation for breast cancer risk reduction among high-risk women. An extensive review of the literature was conducted to gather relevant information pertaining to the Health Promotion Model, self-determination theory, social cognitive theory, Health Belief Model, Transtheoretical Model, theory of planned behavior, and protection motivation theory. An iterative approach was used to summarize the literature related to exercise motivation within each theoretical framework. Protection motivation theory could be used to examine the effects of perceived risk and self-efficacy in motivating women to exercise to facilitate health-related behavioral change. Evidence-based research within a chosen theoretical model can aid practitioners when making practical recommendations to reduce breast cancer risk.

  14. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catalytic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final...

  15. A theoretical study of absorption equilibria in silicon CVD

    NARCIS (Netherlands)

    Gardeniers, Johannes G.E.; Giling, L.J.; de Jong, F.; van der Eerden, J.P.

    1990-01-01

    As part of a theoretical study of adsorption processes in the chemical vapour deposition of silicon, thermochemical data are derived for the adsorption of Si-H species on the Si(111) and the dimer-reconstructed Si(001)-(2 x 1) surfaces. Essential contributions to the heats of adsorption appear to be

  16. Couples coping with cancer: exploration of theoretical frameworks from dyadic studies.

    Science.gov (United States)

    Regan, Tim W; Lambert, Sylvie D; Kelly, Brian; Falconier, Mariana; Kissane, David; Levesque, Janelle V

    2015-12-01

    A diagnosis of cancer and subsequent treatment are distressing not only for the person directly affected, but also for their intimate partner. The aim of this review is to (a) identify the main theoretical frameworks underpinning research addressing dyadic coping among couples affected by cancer, (b) summarise the evidence supporting the concepts described in these theoretical frameworks, and (c) examine the similarities and differences between these theoretical perspectives. A literature search was undertaken to identify descriptive studies published between 1990 and 2013 (English and French) that examined the interdependence of patients' and partners' coping, and the impact of coping on psychosocial outcomes. Data were extracted using a standardised form and reviewed by three of the authors. Twenty-three peer-reviewed manuscripts were identified, from which seven theoretical perspectives were derived: Relationship-Focused Coping, Transactional Model of Stress and Coping, Systemic-Transactional Model (STM) of dyadic coping, Collaborative Coping, Relationship Intimacy model, Communication models, and Coping Congruence. Although these theoretical perspectives emphasised different aspects of coping, a number of conceptual commonalities were noted. This review identified key theoretical frameworks of dyadic coping used in cancer. Evidence indicates that responses within the couple that inhibit open communication between partner and patient are likely to have an adverse impact on psychosocial outcomes. Models that incorporate the interdependence of emotional responses and coping behaviours within couples have an emerging evidence base in psycho-oncology and may have greatest validity and clinical utility in this setting. Copyright © 2015 John Wiley & Sons, Ltd.

  17. A theoretical and spectroscopic study of co-amorphous naproxen and indomethacin

    DEFF Research Database (Denmark)

    Löbmann, Korbinian; Laitinen, Riikka; Grohganz, Holger

    2013-01-01

    . In this study, the co-amorphous drug mixture containing naproxen (NAP) and indomethacin (IND) was investigated using infrared spectroscopy (IR) and quantum mechanical calculations. The structures of both drugs were optimized as monomer, homodimer and heterodimer using density functional theory and used...... for the calculation of IR spectra. Conformational analysis confirmed that the optimized structures were suitable for the theoretical prediction of the spectra. Vibrational modes from the calculation could be matched with experimentally observed spectra for crystalline and amorphous NAP and IND, and it could be shown...... that both drugs exist as homodimers in their respective individual amorphous form. With the results from the experimental single amorphous drugs and theoretical homodimers, a detailed analysis of the experimental co-amorphous and theoretical heterodimer spectra was performed and evaluated. It is suggested...

  18. Spin-dependent Hall effect in degenerate semiconductors: a theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

    2008-10-15

    The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V{sub SDH}) is derived, and drift and diffusive contributions to V{sub SDH} are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V{sub SDH} increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V{sub SDH} is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.

  19. Spin-dependent Hall effect in degenerate semiconductors: a theoretical study

    International Nuclear Information System (INIS)

    Idrish Miah, M

    2008-01-01

    The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V SDH ) is derived, and drift and diffusive contributions to V SDH are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V SDH increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V SDH is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.

  20. Theoretical Studies Of Nucleation Kinetics And Nanodroplet Microstructure

    International Nuclear Information System (INIS)

    Wilemski, Gerald

    2009-01-01

    The goals of this project were to (1) explore ways of bridging the gap between fundamental molecular nucleation theories and phenomenological approaches based on thermodynamic reasoning, (2) test and improve binary nucleation theory, and (3) provide the theoretical underpinning for a powerful new experimental technique, small angle neutron scattering (SANS) from nanodroplet aerosols, that can probe the compositional structure of nanodroplets. This report summarizes the accomplishments of this project in realizing these goals. Publications supported by this project fall into three general categories: (1) theoretical work on nucleation theory (2) experiments and modeling of nucleation and condensation in supersonic nozzles, and (3) experimental and theoretical work on nanodroplet structure and neutron scattering. These publications are listed and briefly summarized in this report.

  1. Experimental and theoretical studies of bombardment induced surface morphology changes

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Williams, J.S.

    1980-01-01

    In this review results of experimental and theoretical studies of solid surface morphology changes due to ion bombardment are discussed. An attempt is undertaken to classify the observed specific features of a structure, generated by ion bombardment [ru

  2. Theoretical Physics Division

    International Nuclear Information System (INIS)

    This report is a survey of the studies done in the Theoretical Physics Division of the Nuclear Physics Institute; the subjects studied in theoretical nuclear physics were the few-nucleon problem, nuclear structure, nuclear reactions, weak interactions, intermediate energy and high energy physics. In this last field, the subjects studied were field theory, group theory, symmetry and strong interactions [fr

  3. Experimental and theoretical study of magnetohydrodynamic ship models.

    Science.gov (United States)

    Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe

    2017-01-01

    Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

  4. Experimental and theoretical study of magnetohydrodynamic ship models.

    Directory of Open Access Journals (Sweden)

    David Cébron

    Full Text Available Magnetohydrodynamic (MHD ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

  5. Theoretical model simulations for the global Thermospheric Mapping Study (TMS) periods

    Science.gov (United States)

    Rees, D.; Fuller-Rowell, T. J.

    Theoretical and semiempirical models of the solar UV/EUV and of the geomagnetic driving forces affecting the terrestrial mesosphere and thermosphere have been used to generate a series of representative numerical time-dependent and global models of the thermosphere, for the range of solar and geoamgnetic activity levels which occurred during the three Thermospheric Mapping Study periods. The simulations obtained from these numerical models are compared with observations, and with the results of semiempirical models of the thermosphere. The theoretical models provide a record of the magnitude of the major driving forces which affected the thermosphere during the study periods, and a baseline against which the actual observed structure and dynamics can be compared.

  6. Theoretical and experimental studies on electric field and confinement in helical systems

    International Nuclear Information System (INIS)

    Sanuki, H.; Itoh, K.; Todoroki, J.; Ida, K.; Idei, H.; Iguchi, H.; Yamada, H.

    1994-06-01

    The present study consists of two parts. The first part is oriented to a theoretical model of selfconsistent analysis to determine simultaneously the electric field and loss cone boundary in heliotron/torsatron configurations under the influence of nonclassical particle losses. The second part is referred to the analysis on NBI heated and ECH plasmas in Compact Helical System (CHS) device. A comparison is made between theoretical results and experimental observations. (author)

  7. Theoretical Studies of Nanoclusters (Briefing Charts)

    Science.gov (United States)

    2015-07-23

    nanoclusters. However, scanning transmission electron microscopy ( STEM ) measures show cluster inversion occurred to produce MgyCux(!) a) copper atoms b...methane (née CLL -1) as a potential explosive ingredient: a theoretical study”, Propellants, Explosives, Pyrotechnics 38, 9-13 (2013). Jesus Paulo L

  8. Theoretical and experimental study of modes associated to ion cyclotron heating on TFR

    International Nuclear Information System (INIS)

    Pignol, L.

    1985-05-01

    In this work, the ion cyclotron wave evolution is followed thanks to a coherent scattering device using carbon dioxide laser radiation. A theoretical part presents the dispersion equation that obey the waves excited in the plasma by antenna emitting ion cyclotron frequency. Then measurements given by the diagnostic are given. Fast and slow waves evidenced theoretically, are experimentally observed. Two simple theoretical models allow to extract physical quantities characteristics of the two modes. These two modes are followed along the radial coordinate of the tore and their behavior through the hybrid curve is studied. measured spectra shape is shown to confirm the described numerical code validity. Time study of the slow wave shows of internal relaxation phenomenon of plasma [fr

  9. A theoretical and experimental study of microshield circuits

    Science.gov (United States)

    Dib, Nihad I.; Drayton, Rhonda F.; Katehi, Linda P. B.

    1993-05-01

    The novel type of monolithic planar transmission line presently studied theoretically and experimentally operates without via-holes or ground-equalizing air bridges; it also radiates less than conventional coplanar waveguides and furnishes a wide range of impedances in virtue of its many design parameters. The space-domain integral equation method is used to analyze several discontinuities of the proposed line. It is shown that the proposed line discontinuities radiate less than the corresponding coplanar waveguide cases.

  10. An Activity Theoretical Approach to Social Interaction during Study Abroad

    Science.gov (United States)

    Shively, Rachel L.

    2016-01-01

    This case study examines how one study abroad student oriented to social interaction during a semester in Spain. Using an activity theoretical approach, the findings indicate that the student not only viewed social interaction with his Spanish host family and an expert-Spanish-speaking age peer as an opportunity for second language (L2) learning,…

  11. Theoretical study of catalytic hydrogenation of oxirane and its methyl ...

    African Journals Online (AJOL)

    C3H6O) is its methyl derivative. Theoretical studies on catalytic hydrogenation of both compounds, in presence of aluminium chloride (AlCl3) catalyst, are carried out. The products of reactions are ethanol and propan-1-ol from oxirane and ...

  12. Charging/discharging processes in nanocrystaline MOS structures - Theoretical study

    International Nuclear Information System (INIS)

    Tanous, D; Mazurak, A; Majkusiak, B

    2016-01-01

    We present the study of impact of some parameters of the metal-insulator-semiconductor structure with nanocrystals embedded in the insulator layer on the current-voltage and capacitance-voltage characteristics with the bias voltage ramp rate as a parameter. The developed model is used as a tool for theoretical understanding the physics behind charging and discharging processes in the considered structures. (paper)

  13. Theoretical Studies in Elementary Particle Physics

    Energy Technology Data Exchange (ETDEWEB)

    Collins, John C.; Roiban, Radu S

    2013-04-01

    This final report summarizes work at Penn State University from June 1, 1990 to April 30, 2012. The work was in theoretical elementary particle physics. Many new results in perturbative QCD, in string theory, and in related areas were obtained, with a substantial impact on the experimental program.

  14. Micro sociological study of family relationships: heuristic potential theoretical principles

    Directory of Open Access Journals (Sweden)

    O. P. Zolotnyik

    2015-03-01

    Full Text Available This article is devoted to demonstrate the heuristic potential of theoretical principles by microsoсiological analysis of one of the indicators of family – family relations. Theoretical analysis of the interaction experience is quite large, but there is the question about it’s possibility to describe the specifics of that relationship that arise in family interaction. The study of family relationships requires an integrated approach to the comprehension of many related components: system of spouses value orientations, family life cycle, socio­economic living conditions of couple. However, the accentuation exactly on action­behavioral aspect allows to make assumptions about correlations between: success of family interaction and microclimate in the family; satisfaction level of interpersonal interaction and overall satisfaction with marriage, familiarity of family interaction and density of childbearing, and so on. The presentation of microsoсiological theoretical achievements will be carried out of sociological schools, orientations and their members that are the most popular references in this area. this paper will presents the theory of exchange, supporters of symbolic interactionism, dramatic and etnometodological approach and family systems theory.

  15. Theoretical study of the lowest-lying electronic states of Aluminium monoiodide

    International Nuclear Information System (INIS)

    Taher, F.; Kabbani, A.; Ani-El Houte, W.

    2004-01-01

    Full text.The spectroscopic study of Aluminium monohalides, especially the Aluminium monoiodide, is important for monitoring such species in high temperature fast-flow reactors. Theoretical calculations of AlI are not available, whereas several studies have been done for the other aluminium monohalides. In this work, CAS-SCF/MRCI calculations are performed for the lowest-lying electronic states of AlI in a range of internuclear distance between 2.30 A and 2.80 A. Ab-initio calculations have been effectuated by using the computational chemistry program Molpro. The basis set used in this study for aluminium atom is that used by Langhoff for aluminium monohalides, of contractions using atomic natural orbitals and a pseudopotential is used for iode. Accurate theoretical spectroscopic constants and potential curves are obtained for the ground state X 1 Σ + and the first excited states a 3 Π and A 1 Π. The calculated values of Te, ωe, ωexe and re of these states are compatible with the experimental results. An ordering of states is represented for the lowest five predicted singlet and lowest five predicted triplet states. These results provide a big support to determine the analogy in the ordering of the electronic states in AlF, AlBr and AlI respectively at lower energies. These theoretical results identify a set of electronic singlet and triplet states unobserved experimentally

  16. Experimental and theoretical study of steam condensation induced water hammer phenomena

    International Nuclear Information System (INIS)

    Barna, Imre Ferenc; Baranyai, Gabor; Ezsoel, Gyoergy

    2009-01-01

    We investigate steam condensation induced water hammer (waha) phenomena and present experimental and theoretical results. Some of the experiments were performed in the PMK-2 facility, which is a full-pressure thermohydraulic model of the nuclear power plant of VVER-440/312 type and located in the Atomic Energy Research Institute Budapest, Hungary. Other experiments were done in the ROSA facility in Japan. On the theoretical side waha is studied and analyzed with the WAHA3 model based on two-phase flow six first-order partial differential equations that present one dimensional, surface averaged mass, momentum and energy balances. A second order accurate high-resolution shock-capturing numerical scheme was applied with different kind of limiters in the numerical calculations. The applied two-fluid model shows some similarities to Relap5 which is widely used in the nuclear industry to simulate nuclear power plant accidents. Experimentally measured and theoretically calculated waha pressure peaks are in qualitative agreement. (author)

  17. The pressure distribution for biharmonic transmitting array: theoretical study

    Science.gov (United States)

    Baranowska, A.

    2005-03-01

    The aim of the paper is theoretical analysis of the finite amplitude waves interaction problem for the biharmonic transmitting array. We assume that the array consists of 16 circular pistons of the same dimensions that regrouped in two sections. Two different arrangements of radiating elements were considered. In this situation the radiating surface is non-continuous without axial symmetry. The mathematical model was built on the basis of the Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation. To solve the problem the finite-difference method was applied. On-axis pressure amplitude for different frequency waves as a function of distance from the source, transverse pressure distribution of these waves at fixed distances from the source and pressure amplitude distribution for them at fixed planes were examined. Especially changes of normalized pressure amplitude for difference frequency were studied. The paper presents mathematical model and some results of theoretical investigations obtained for different values of source parameters.

  18. Theoretical study of fractal growth and stability on surface

    DEFF Research Database (Denmark)

    Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2009-01-01

    We perform a theoretical study of the fractal growing process on surface by using the deposition, diffusion, aggregation method. We present a detailed analysis of the post-growth processes occurring in a nanofractal on surface. For this study we developed a method which describes the internal...... dynamics of particles in a fractal and accounts for their diffusion and detachment. We demonstrate that these kinetic processes are responsible for the formation of the final shape of the islands on surface after the post-growth relaxation....

  19. Theoretical and experimental study of resonant inelastic X-ray scattering for NiO

    International Nuclear Information System (INIS)

    Kotani, A.; Matsubara, M.; Uozumi, T.; Ghiringhelli, G.; Fracassi, F.; Dallera, C.; Tagliaferri, A.; Brookes, N.B.; Braicovich, L.

    2006-01-01

    Resonant inelastic X-ray scattering (RIXS) spectra for Ni 2p to 3d excitation and 3d to 2p de-excitation of NiO are studied both theoretically and experimentally. Theoretical calculations with a single impurity Anderson model (SIAM) describe the charge transfer (CT) and d-d excitations in RIXS, and detailed study is made for the CT energy. High resolution RIXS measurements reveal the precise d-d excitation structure and its polarization dependence, and they are well reproduced by the SIAM calculation

  20. Theoretical Study on the Flow of Refilling Stage in a Safety Injection Tank

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Sang [Halla Univ. Daejeon (Korea, Republic of)

    2017-10-15

    In this study, a theoretical analysis was performed to the flow of refilling stage in a safety injection tank, which is the core cooling system of nuclear power plant in an emergency. A theoretical model was proposed with a nonlinear governing equation defining on the flow of the refilling process of the coolant. Utilizing the Taylor-series expansion, the 1st - order approximation flow equation was obtained, along with its analytic solution of closed type, which could predict accurately the variations of free surface height and flow rate of the coolant. The availability of theoretical result was confirmed by comparing with previous experimental results.

  1. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

    Bodek, A.; Ferbel, T.; Melissinos, A.C.; Slattery, P.; Tipton, P.; Das, A.; Hagen, C.R.; Rajeev, S.G.; Okubo, S.; Orr, L.

    1993-01-01

    The various components of the high-energy physics research program at the University of Rochester are presented. (I)Fixed-target experimentation at FNAL includes studies of direct photon production by p and π on H, Be, and Cu, and hybrid mesons and other physics issues in Coulomb excitation at high energies. (II)The status of the GEM (Gammas, Electrons, and Muons) Experiment at the SSC is given. (III)The D-Zero experiment at FNAL is reviewed. (IV)Deep inelastic lepton--nucleon scattering experiments are summarized: electron scattering experiments at SLAC, FNAL neutrino quad triplet runs, FNAL neutrino sign selected experiments, and SDC cosmic ray test and test beam calibration. (V)Studies of nonlinear QED at SLAC concentrated on a study of QED at critical field strength in intense laser--high-energy electron collisions. (VI)Development work on the Collider Detector at Fermilab (CDF) emphasized the CDF silicon vertex detector, the end plug calorimeter, and the SDC tile/fiber calorimetry. (VII)The theoretical physics effort is sketched

  2. A theoretical study of rotatable renewable energy system for stratospheric airship

    International Nuclear Information System (INIS)

    Lv, Mingyun; Li, Jun; Zhu, Weiyu; Du, Huafei; Meng, Junhui; Sun, Kangwen

    2017-01-01

    Highlights: • A new rotatable renewable energy system is designed for stratospheric airship. • A theoretical model of optimal rotation angle and required area are studied. • The effects of latitude and date on output energy per day are investigated. • The advantages of the rotatable renewable energy system are studied. - Abstract: Renewable energy system is very critical for solving the energy problem of a long endurance stratospheric airship. Output performance of the traditional solar array fixed on the upper surface of the airship remains to be improved to reduce the area and weight of renewable energy system. Inspired by the solar tracking system and kirigami, a rotatable renewable energy system (mainly including solar array) is designed to improve the current status of the energy system. The advantages of the rotatable solar array are studied using a MATLAB computer program based on the theoretical model established in this paper. The improvements in output energy and required area of the solar array were compared between the traditional airship and improved one. Studies had shown that the rotatable renewable energy system made the total weight of energy system decreased by 1000 kg when the maximum design speed of the airship was greater than 22 m/s. The results demonstrate that the rotatable renewable energy system for the airship can be a good way to improve the output performance of solar array, and the conceptual design and theoretical model suggest a pathway towards solving the energy problem of a stratospheric airship.

  3. Experimental studies of caesium iodide aerosol condensation: theoretical interpretation

    International Nuclear Information System (INIS)

    Beard, A.M.; Benson, C.G.; Horton, K.D.; Buckle, E.R.

    1990-07-01

    Caesium iodide is predicted to be a significant source of fission product aerosols during the course of a severe accident in a pressurised water reactor (PWR). The nucleation and growth of caesium iodide aerosols have been studied using a plume chamber and the results compared with theoretical values calculated using the approach developed by Buckle for aerosol nucleation. The morphology of the particles was studied using scanning electron microscopy (SEM) and transmission optical microscopy (TOM), whilst the particle size distributions were determined from differential mobility (DMPS) and aerodynamic (APS) measurements. (author)

  4. Strong correlation effects in theoretical STM studies of magnetic adatoms

    Science.gov (United States)

    Dang, Hung T.; dos Santos Dias, Manuel; Liebsch, Ansgar; Lounis, Samir

    2016-03-01

    We present a theoretical study for the scanning tunneling microscopy (STM) spectra of surface-supported magnetic nanostructures, incorporating strong correlation effects. As concrete examples, we study Co and Mn adatoms on the Cu(111) surface, which are expected to represent the opposite limits of Kondo physics and local moment behavior, using a combination of density functional theory and both quantum Monte Carlo and exact diagonalization impurity solvers. We examine in detail the effects of temperature T , correlation strength U , and impurity d electron occupancy Nd on the local density of states. We also study the effective coherence energy scale, i.e., the Kondo temperature TK, which can be extracted from the STM spectra. Theoretical STM spectra are computed as a function of STM tip position relative to each adatom. Because of the multiorbital nature of the adatoms, the STM spectra are shown to consist of a complicated superposition of orbital contributions, with different orbital symmetries, self-energies, and Kondo temperatures. For a Mn adatom, which is close to half-filling, the STM spectra are featureless near the Fermi level. On the other hand, the quasiparticle peak for a Co adatom gives rise to strongly position-dependent Fano line shapes.

  5. Correction: Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review

    Directory of Open Access Journals (Sweden)

    Kleinstreuer Clement

    2011-01-01

    Full Text Available Abstract Correction to Kleinstreuer C, Feng Y: Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review. Nanoscale Research Letters 2011, 6:229.

  6. Theoretical Studies of Strongly Interacting Fine Particle Systems

    Science.gov (United States)

    Fearon, Michael

    Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.

  7. Theoretical studies of transition metal complexes with nitriles and isocyanides

    International Nuclear Information System (INIS)

    Kuznetsov, Maksim L

    2002-01-01

    Theoretical studies of transition metal complexes with nitriles and isocyanides are reviewed. The electronic structures and the nature of coordination bonds in these complexes are discussed. The correlation between the electronic structures of transition metal complexes with nitriles and isocyanides and their structural properties, spectroscopic characteristics, and reactivities are considered. The bibliography includes 121 references.

  8. The generation of charge carriers in semi conductors – A theoretical study

    CSIR Research Space (South Africa)

    Kiarii, EM

    2017-04-01

    Full Text Available , vol. 678: 167-176 The generation of charge carriers in semi conductors – A theoretical study Kiarii EM Govender, Krishna K Ndungu PG Govender PG ABSTRACT: A systematic study of electronic and optical properties of titanium dioxide under...

  9. Theoretical study on loss of coolant accident of a research reactor

    International Nuclear Information System (INIS)

    Lee, Kwon-Yeong; Kim, Wan-Soo

    2016-01-01

    Highlights: • A theoretical model of siphon breaking phenomena was developed. • A general formula using Chisholm coefficient B was proposed. • The safety requirements regarding a loss of coolant accident of research reactors could be found out. - Abstract: Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous efflux of water. In order to prevent water efflux, an additional facility is necessary. A siphon breaker is a type of safety facility that can resist the loss of coolant effectively. However, analysis of siphon breaking is complex since it comprises two-phase flow and there are many inputs to be considered. For this reason, we analyzed the experimental results to develop a theoretical model of siphon breaking phenomena. Developed model is based on fluid mechanics and Chisholm model. From Bernoulli’s equation, the velocity and quantity as well as undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be calculated. The Chisholm model, which is able to analyze the two-phase flow, can predict the results in a manner similar to those obtained from a real-scale experiment, and a general formula using Chisholm coefficient B was proposed in this study. Also, we verified the theoretical model and concluded that it is possible to analyze the siphon breaking. Moreover, the design conditions that can satisfy the safety requirements regarding a loss of coolant accident of research reactors could be found out by using the theoretical model. In conclusion, we propose the theoretical model which can analyze the siphon breaking as real, and it is helpful not only to analyze but also to design the siphon breaker.

  10. THEORETICAL AND EXPERIMENTAL STUDY OF STRUCTURES SUBJECTED TO EARTHQUAKES

    Energy Technology Data Exchange (ETDEWEB)

    Soubirou, A.

    1967-12-31

    The object of the study was the investigation of the behaviour of structures subject to earthquakes. After .describing and analysing seismic movements, useful concepts for earthquake-proofing structures are lintroduced. Then, the dynamic behaviour of systems with n degrees of freedom was studied in order to evolve the theoretical computation of seismic behaviour, a typical application being reticulated structures. The next stage was showing the computational procedure for seismic spectra and the natural frequencies of buildings, an attempt being made to define earthquake-proofing criteria for a special type of reinforced-concrete construction. . The last matter dealt with is elastoplastic behaviour of structures, a study of increasingly growing importance.

  11. A theoretical study on interaction of proline with gold cluster

    Indian Academy of Sciences (India)

    with Au3 (Pakiari and Jamshidi 2007) and interaction of. ∗. Author for correspondence (harjinder.singh@iiit.ac.in) small gold clusters with xDNA base pairs (Sharma et al. 2009) have motivated us to carry out a theoretical study on interaction of proline with gold nanoparticles. Proline is unique among the natural amino acids ...

  12. Box-Cox Test: the theoretical justification and US-China empirical study

    Directory of Open Access Journals (Sweden)

    Tam Bang Vu

    2011-01-01

    Full Text Available In econometrics, the derivation of a theoretical model leads sometimes to two econometric models, which can be considered justified based on their respective approximation approaches. Hence, the decision of choosing one between the two hinges on applied econometric tools. In this paper, the authors develop a theoretical econometrics consumer maximization model to measure the flow of durables’ expenditures where depreciation is added to former classical econometrics model. The proposed model was formulated in both linear and logarithmic forms. Box-Cox tests were used to choose the most appropriate one among them. The proposed model was then applied to the historical data from the U.S. and China for a comparative study and the results discussed.

  13. Theoretical Foundations of Study of Cartography

    Science.gov (United States)

    Talhofer, Václav; Hošková-Mayerová, Šárka

    2018-05-01

    Cartography and geoinformatics are technical-based fields which deal with modelling and visualization of landscape in the form of a map. The theoretical foundation is necessary to obtain during study of cartography and geoinformatics based mainly on mathematics. For the given subjects, mathematics is necessary for understanding of many procedures that are connected to modelling of the Earth as a celestial body, to ways of its projection into a plane, to methods and procedures of modelling of landscape and phenomena in society and visualization of these models in the form of electronic as well as classic paper maps. Not only general mathematics, but also its extension of differential geometry of curves and surfaces, ways of approximation of lines and surfaces of functional surfaces, mathematical statistics and multi-criterial analyses seem to be suitable and necessary. Underestimation of the significance of mathematical education in cartography and geoinformatics is inappropriate and lowers competence of cartographers and professionals in geographic information science and technology to solve problems.

  14. Studies In Theoretical High Energy Particle Physics

    Energy Technology Data Exchange (ETDEWEB)

    Keung, Wai Yee [Univ. of Illinois, Chicago, IL (United States)

    2017-07-01

    This is a final technical report for grant no. DE-SC0007948 describing research activities in theoretical high energy physics at University of Illinois at Chicago for the whole grant period from July 1, 2012 to March 31, 2017.

  15. Experimental and theoretical studies of manganite and magnetite compounds

    International Nuclear Information System (INIS)

    Srinitiwarawong, Chatchai

    2002-01-01

    In the recent years interest in the transition oxide compounds has renewed among researchers in the field of condensed matter physics. This thesis presents the studies of the two families of the transition oxides, the manganite and magnetite compounds. Manganite has regained the interest since the discovery of the large magnetoresistance around its Curie temperature in 1990s. Magnetite on the other hand is the oldest magnetic material known to man however some of its physical properties are still controversial. The experimental works address some basic properties of these compounds when fabricated in the form of thin films. These include the resistivity measurements and magnetic measurements as well as the Hall effect. The various models of transport mechanism have been compared. The magnetic field and the temperature dependence of magnetoresistance have also been studied. Simple devices such as an artificial grain boundary and bilayers thin film have been investigated. The second part of this thesis concentrates on the theoretical aspects of the fundamental physics behind these two compounds. The problem of electrons tunnelling between the magnetite electrodes has been addressed taking into account the surface effect with distortion. The last chapter presents a theoretical study of the spinless-Hubbard model which is the simplest approximation of the conduction electrons in magnetite and manganite. The results are obtained from the Hartree-Fock and the Hubbard-I approximations as well as the exact diagonalisation method. (author)

  16. A Comparative Study of Theoretical Graph Models for Characterizing Structural Networks of Human Brain

    Directory of Open Access Journals (Sweden)

    Xiaojin Li

    2013-01-01

    Full Text Available Previous studies have investigated both structural and functional brain networks via graph-theoretical methods. However, there is an important issue that has not been adequately discussed before: what is the optimal theoretical graph model for describing the structural networks of human brain? In this paper, we perform a comparative study to address this problem. Firstly, large-scale cortical regions of interest (ROIs are localized by recently developed and validated brain reference system named Dense Individualized Common Connectivity-based Cortical Landmarks (DICCCOL to address the limitations in the identification of the brain network ROIs in previous studies. Then, we construct structural brain networks based on diffusion tensor imaging (DTI data. Afterwards, the global and local graph properties of the constructed structural brain networks are measured using the state-of-the-art graph analysis algorithms and tools and are further compared with seven popular theoretical graph models. In addition, we compare the topological properties between two graph models, namely, stickiness-index-based model (STICKY and scale-free gene duplication model (SF-GD, that have higher similarity with the real structural brain networks in terms of global and local graph properties. Our experimental results suggest that among the seven theoretical graph models compared in this study, STICKY and SF-GD models have better performances in characterizing the structural human brain network.

  17. Theoretical and experimental study of thermoacoustic engines

    Science.gov (United States)

    Raspet, Richard; Bass, Henry E.; Arnott, W. P.

    1992-12-01

    A three year study of thermoacoustic engines operating as prime movers and refrigerators was completed. The major thrust of this effort was the use and theoretical description of ceramic honeycomb structures as the active element in thermoacoustic engines. An air-filled demonstration prime mover was constructed and demonstrated at Acoustical Society of America and IEE meetings. A helium-filled test prime mover was designed and built an is being employed in studies of the threshold of oscillation as a function of temperature difference and pressure. In addition, acoustically based theories of the thermoacoustic engine have been developed and tested for a parallel plate stack at the Naval Postgraduate School and for a honeycomb stack at the University of Mississippi. Most of this work is described in detail in the attached publications. In this report we will give an overview of the research completed to date and its relationship to work performed at the Naval Postgraduate School and to future work at the University of Mississippi.

  18. Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

    Science.gov (United States)

    Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel

    2012-10-01

    This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph2Tz) and some oligomeric derivatives. Ph2Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

  19. EFFICIENCY OF ISO 9001 IN PORTUGAL: A QUALITATIVE STUDY FROM A HOLISTIC THEORETICAL PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Alcina Dias

    2013-03-01

    Full Text Available The purpose of this paper is to analy se the efficiency of ISO 9001 from a holistic theoretical approach where the Contingency theory, the Institutional theory and the Resources-Based View are integrated. The study was carried out in companies of different sectors of activity in Portugal, based on a qualitative methodology (interviews. The fact of the interviews having been undertaken under an ISO 9001 structure made it easier for companies to grasp the issues under investigation. An ISO 9001 characterisation was carried out on a theoretical framework approach and findings point out efficiency gains and revealed that the absence of ISO 9001 would work as a competitive disadvantage. The contribution of this research aims to reinforce the state of art as concerns the theoretical scope of analysis of these issues enriched by the case study achievement.

  20. Joint Experimental and Theoretical Study on Vibrational Excitation Cross Sections for Electron Collisions with Diacetylene

    Czech Academy of Sciences Publication Activity Database

    Čurík, Roman; Paidarová, Ivana; Allan, M.; Čársky, Petr

    2014-01-01

    Roč. 118, č. 41 (2014), s. 9734-9744 ISSN 1089-5639 R&D Projects: GA ČR GAP208/11/0452; GA MŠk LD14088 Institutional support: RVO:61388955 Keywords : diacetylenes * electron collision * theoretical study Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.693, year: 2014

  1. Theoretical Study of the Compound Parabolic Trough Solar Collector

    OpenAIRE

    Dr. Subhi S. Mahammed; Dr. Hameed J. Khalaf; Tadahmun A. Yassen

    2012-01-01

    Theoretical design of compound parabolic trough solar collector (CPC) without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67)% at mass flow rate between (0.02-0.03) kg/s at concentration ratio of (3.8) without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

  2. Theoretical and experimental studies on transient forced convection heat transfer of helium gas

    International Nuclear Information System (INIS)

    Liu, Qiusheng; Fukuda, Katsuya; Shibahara, Makoto

    2008-01-01

    Forced convection transient heat transfer for helium gas at various periods of exponential increase of heat input to a horizontal cylinder and a plate (ribbon) one was experimentally and theoretically studied. In the experimental studies, the authors measured heat flux, surface temperature, and transient heat transfer coefficients for forced convection flow of helium gas over a horizontal cylinder and a plate (ribbon) one under wide experimental conditions. Empirical correlations for quasi-steady-state heat transfer and transient heat transfer were obtained based on the experimental data. In the theoretical study, transient heat transfer was numerically solved based on a turbulent flow model. The values of numerical solution for surface temperature and heat flux were compared and discussed with authors' experimental data. (author)

  3. A Case-Study Assignment to Teach Theoretical Perspectives in Abnormal Psychology.

    Science.gov (United States)

    Perkins, David V.

    1991-01-01

    Describes an assignment that requires students to organize, prepare, and revise a case study in abnormal behavior. Explains that students employ a single theoretical perspective in preparing a report on a figure from history, literature, the arts, or current events. Discusses the value of the assignment for students. (SG)

  4. Medication competency of nurses according to theoretical and drug calculation online exams: A descriptive correlational study.

    Science.gov (United States)

    Sneck, Sami; Saarnio, Reetta; Isola, Arja; Boigu, Risto

    2016-01-01

    Medication administration is an important task of registered nurses. According to previous studies, nurses lack theoretical knowledge and drug calculation skills and knowledge-based mistakes do occur in clinical practice. Finnish health care organizations started to develop a systematic verification processes for medication competence at the end of the last decade. No studies have yet been made of nurses' theoretical knowledge and drug calculation skills according to these online exams. The aim of this study was to describe the medication competence of Finnish nurses according to theoretical and drug calculation exams. A descriptive correlation design was adopted. Participants and settings All nurses who participated in the online exam in three Finnish hospitals between 1.1.2009 and 31.05.2014 were selected to the study (n=2479). Quantitative methods like Pearson's chi-squared tests, analysis of variance (ANOVA) with post hoc Tukey tests and Pearson's correlation coefficient were used to test the existence of relationships between dependent and independent variables. The majority of nurses mastered the theoretical knowledge needed in medication administration, but 5% of the nurses struggled with passing the drug calculation exam. Theoretical knowledge and drug calculation skills were better in acute care units than in the other units and younger nurses achieved better results in both exams than their older colleagues. The differences found in this study were statistically significant, but not high. Nevertheless, even the tiniest deficiency in theoretical knowledge and drug calculation skills should be focused on. It is important to identify the nurses who struggle in the exams and to plan targeted educational interventions for supporting them. The next step is to study if verification of medication competence has an effect on patient safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Theoretical study of reaction dynamics in radiation chemistry

    International Nuclear Information System (INIS)

    Tachiya, Masanori

    2008-01-01

    The period from late 1950's to early 1970's was golden age of radiation chemistry. During this period the hydrated electron was discovered, various new phenomena were found in ionic processes in liquid hydrocarbons, and the trapped electron and electron tunneling were discovered in organic glasses. In those days radiation chemistry was a vast treasure-house of theoretical problems. We could find not only problems special to radiation chemistry but also many problems interesting as general physical chemistry. In this review I explain how some theoretical problems discovered in the field of radiation chemistry have evolved into those of general physical chemistry, with special emphasis on my own work. (author)

  6. Theoretical studies of fusion physics. Volume I. Summary. Final report

    International Nuclear Information System (INIS)

    1983-01-01

    Theoretical studies were performed on each of the following topics: (1) absorption of waves near the cyclotron frequency by relativistic electrons in EBT, (2) power balance in a stable, adiabatic hot electron annulus, (3) whistler instability in a relativistic electron annulus, (4) adiabatic limits on electron temperature in the EBT annulus, and (5) summary of a model of the EBT ring heating/loss process

  7. A theoretical and experimental EPFM study of cracks emanating from a hole

    International Nuclear Information System (INIS)

    Broekhoven, M.J.G.

    1978-01-01

    Results are presented of a combined theoretical and experimental study on the onset of crack extension in the EPFM regime for through cracks emanating from a circular hole in a plate under tensile load, with emphasis on the applicability of the J-concept for predicting such extensions. This configuration was selected both because of its general importance and as a first approximation for a nozzle-to-vessel geometry. Theoretical investigations consisted of elastic-plastic finite element computations both for 3-point bend specimens and for plate geometry. J values were calculated using the contour-integral definition for J, and by the method of virtual crack extension. The applicability of simplified analytical approximations for J was also investigated. COD data were derived from finite element computed displacements. Experimental investigations included Jsub(Ic) tests on a series of bend specimens and crack extensions tests on a series of cracked perforated plate models. For practical reasons aluminium 2024-T 351 was selected as a suitable model material within the aims of the study. Onset of crack extension was determined by the heat-tinting procedure throughout the experiments, in some cases supplemented by fractographic investigations. The various theoretical solutions and experimental observations were compared and a number of conclusions were drawn. (author)

  8. THEORETICAL ANALYSIS STUDY OF FORMATION OF FUTURE LEGAL LAWYERS

    Directory of Open Access Journals (Sweden)

    Eugene Stepanovich Shevlakov

    2015-09-01

    Full Text Available The article deals with topical issues of formation of legal consciousness of future lawyers in high school. Obtained kinds of legal consciousness of future lawyers, determined its structure. Dedicated components of justice are mutually reinforcing, and provide an opportunity for further development of the personality of the future specialist, their personal growth.The purpose: to carry out theoretical analysis of the problem of formation of legal consciousness of future lawyers.The novelty is based. On the analysis of theoretical appro-aches of pedagogy, psychology, law, the notion of «lawfulness of the future of the law student», which is regarded as a form of social consciousness, which is a set of legal views and feelings, expressing the attitude to the law and legal phenomena that have regulatory in character and which includes know-ledge of legal phenomena and their evaluation from the point of view of fairness and justice, formed in the process of studying in the University.Results: this article analyzes different approaches to understanding the content and essence of the concept of legal consciousness of the legal profession. Define the types and structure of legal consciousness of future lawyers.

  9. EEC-sponsored theoretical studies of gas cloud explosion pressure loadings

    International Nuclear Information System (INIS)

    Briscoe, F.; Curtress, N.; Farmer, C.L.; Fogg, G.J.; Vaughan, G.J.

    1979-01-01

    Estimates of the pressure loadings produced by unconfined gas cloud explosions on the surface of structures are required to assist the design of strong secondary containments in countries where the protection of nuclear installations against these events is considered to be necessary. At the present time, one difficulty in the specification of occurate pressure loadings arises from our lack of knowledge concerning the interaction between the incident pressure waves produced by unconfined gas cloud explosions and large structures. Preliminary theoretical studies include (i) general theoretical considerations, especially with regard to scaling (ii) investigations of the deflagration wave interaction with a wall based on an analytic solution for situations with planar symmetry and the application of an SRD gas cloud explosion code (GASEX 1) for situations with planar and spherical symmetry, and (iii) investigations of the interaction between shock waves and structures for situations with two-dimensional symmetry based on the application of another SRD gas cloud explosion code (GASEX 2)

  10. Theoretical Study of the Compound Parabolic Trough Solar Collector

    Directory of Open Access Journals (Sweden)

    Dr. Subhi S. Mahammed

    2012-06-01

    Full Text Available Theoretical design of compound parabolic trough solar collector (CPC without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67% at mass flow rate between (0.02-0.03 kg/s at concentration ratio of (3.8 without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

  11. Theoretical and experimental studies on critical heat flux in subcooled boiling and vertical flow geometry

    International Nuclear Information System (INIS)

    Staron, E.

    1996-01-01

    Critical Heat Flux is a very important subject of interest due to design, operation and safety analysis of nuclear power plants. Every new design of the core must be thoroughly checked. Experimental studies have been performed using freon as a working fluid. The possibility of transferring of results into water equivalents has been proved. The experimental study covers vertical flow, annular geometry over a wide range of pressure, mass flow and temperature at inlet of test section. Theoretical models of Critical Heat Flux have been presented but only those which cover DNB. Computer programs allowing for numerical calculations using theoretical models have been developed. A validation of the theoretical models has been performed in accordance with experimental results. (author). 83 refs, 32 figs, 4 tabs

  12. Theoretical and experimental study of an energy-reinforced braking radiation photon beam

    International Nuclear Information System (INIS)

    Bertin, Pierre-Yves

    1966-01-01

    This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

  13. Theoretical study on the first kind of density wave instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Zuying, Gao; Jincai, Li; Baocheng, Xu; Zuoyi, Zhang; Cheng, Gao [Institute of Nuclear Energy and Technology, Tsingua Univ., Beijing (China)

    1997-09-01

    The present paper summarizes the theoretical studies carried out by INET (Institute of Nuclear Energy Technology) of Tsinghua University on the first kind of density wave instabilities (DWIs) of natural circulation systems. The analysis methods of DWI and mathematical models of drift flux are presented. Based on the general excess entropy production criterion of non-equilibrium thermodynamics, an energy principle of DWI is established. (author). 10 refs, 16 figs.

  14. Theoretical study of excitonic complexes in semiconductors quantum wells

    International Nuclear Information System (INIS)

    Dacal, Luis Carlos Ogando

    2001-08-01

    A physical system where indistinguishable particles interact with each other creates the possibility of studying correlation and exchange effect. The simplest system is that one with only two indistinguishable particles. In condensed matter physics, these complexes are represented by charged excitons, donors and acceptors. In quantum wells, the valence band is not parabolic, therefore, the negatively charged excitons and donors are theoretically described in a simpler way. Despite the fact that the stability of charged excitons (trions) is known since the late 50s, the first experimental observation occurred only at the early 90s in quantum well samples, where their binding energies are one order of magnitude larger due to the one dimensional carriers confinement. After this, these complexes became the subject of an intense research because the intrinsic screening of electrical interactions in semiconductor materials allows that magnetic fields that are usual in laboratories have strong effects on the trion binding energy. Another rich possibility is the study of trions as an intermediate state between the neutral exciton and the Fermi edge singularity when the excess of doping carriers is increased. In this thesis, we present a theoretical study of charged excitons and negatively charged donors in GaAs/Al 0.3 Ga 0.7 As quantum wells considering the effects of external electric and magnetic fields. We use a simple, accurate and physically clear method to describe these systems in contrast with the few and complex treatments s available in the literature. Our results show that the QW interface defects have an important role in the trion dynamics. This is in agreement with some experimental works, but it disagrees with other ones. (author)

  15. Theoretical and experimental study of collectrons for epithermal neutron flux in reactors

    International Nuclear Information System (INIS)

    Agu, M.N.

    1986-01-01

    A theoretical study of nuclear reactions and electric charge displacements arising in sensitivity to thermal and epithermal neutrons in collectrons allowed a computer code conception. Collectrons in Rhodium, Silver, Cobalt, Hafnium, Erbium, Gadolinium and Holmium have been tested in different radiation fields given by neutron or gamma filters irradiated in different places of Melusine and Siloe reactors. Some emitters were covered with different steel, nickel or zircaloy thicknesses. Theoretical and experimental results are consistent; that validate the computer code and show possibilities and necessity of covering collectron emitters to reduce or cancel the gamma sensitivity and to improve response instantaneity. A selective measurement of epithermal neutron flux can by this way, made by associating two types of collectrons [fr

  16. A theoretical-experimental study of backup bearings

    DEFF Research Database (Denmark)

    Lampe Linhares da Fonseca, Cesar Augusto

    of two types of backup bearings, which are investigated experimentally and theoretically. The first type is a conventional ball bearing commonly used in industrial applications. The second is an unconventional bearing that, which contains pins inside the clearance for the rotor to impact on. The main...... both types of bearings for further investigation. Also, a full failure of the control and a rotor drop on the ball bearing as backup bearing is investigated by removing the magnetic forces. The nonlinear features of the dynamics of the rotor are assessed for different levels of unbalance. It has been...... radial forces. Remaining in this condition, it may lead to permanent damage or total failure of the machine. This is why the backup bearing design has to be carefully planned and investigated as to whether it helps to protect the integrity of the machine. This PhD thesis provides a comprehensive study...

  17. Hash functions and information theoretic security

    DEFF Research Database (Denmark)

    Bagheri, Nasoor; Knudsen, Lars Ramkilde; Naderi, Majid

    2009-01-01

    Information theoretic security is an important security notion in cryptography as it provides a true lower bound for attack complexities. However, in practice attacks often have a higher cost than the information theoretic bound. In this paper we study the relationship between information theoretic...

  18. Theoretical studies in elementary particle physics

    International Nuclear Information System (INIS)

    Collins, J.

    1994-01-01

    This is a report on research conducted at Penn State University under grant number DE-FG02-90ER-40577, from November 1992 to present. The author is a member of the CTEQ collaboration (Coordinated Theoretical and Experimental Project on Quantitative QCD). Some of the work in CTEQ is described in this report. Topics which the authors work has touched include: polarized hard scattering; hard diffraction; small x and perturbative pomeron physics; gauge-invariant operators; fundamental QCD; heavy quarks; instantons and deep inelastic scattering; non-perturbative corrections to τ decay

  19. TMX tandem-mirror experiments and thermal-barrier theoretical studies

    International Nuclear Information System (INIS)

    Simonen, T.C.; Baldwin, D.E.; Allen, S.L.

    1982-01-01

    This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions

  20. Phosphonic drugs: Experimental and theoretical spectroscopic studies of fosfomycin

    Science.gov (United States)

    Chruszcz-Lipska, Katarzyna; Zborowski, Krzysztof K.; Podstawka-Proniewicz, Edyta; Liu, Shaoxuan; Xu, Yizhuang; Proniewicz, Leonard M.

    2011-02-01

    pH and time-dependant changes of fosfomycin molecular structure in an aqueous solution are studied by Raman, NMR, and generalized 2D correlation spectroscopies. Interpretation of the experimental spectra is based on the assumption of formation of different species running on applied physicochemical conditions. Geometries of all possible structures were entirely optimized with the 6-311++G(2df,p) basis set at the B3LYP theoretical level using procedures implemented in the Gaussian '03 set of programs. Harmonic frequency calculations verified the nature of the studied structures and allowed to simulate obtained Raman spectra. The theoretical NMR shielding was calculated using the GIAO method at the same computational level. In addition, in some cases PCM model was used to monitor the influence of water molecules on the NMR spectra. It is shown that in the pH range of 1-2 of fosfomycin aqueous solution oxirane ring is open sequent to nucleophilic attack and forms 1,2-dihydroxyphosphonic acid with small content of its monodeprotonated species. On the other hand, in pH 7 and higher it appears either as 1,2-epoxypropylphosphonic or 1,2-dihydroxyphosphonic dianion depending upon whether hydrolysis took place or not. It is also discussed that Raman marker bands originating from the individual species of fosfomycin can be used to detect and/or to monitor this antibiotic in an aqueous medium (for example urine samples). Hence, depending upon the structure found in urine one can tell about metabolic processes of this antibiotic in the body.

  1. Mechanical Behaviour of 3D Multi-layer Braided Composites: Experimental, Numerical and Theoretical Study

    Science.gov (United States)

    Deng, Jian; Zhou, Guangming; Ji, Le; Wang, Xiaopei

    2017-12-01

    Mechanical properties and failure mechanisms of a newly designed 3D multi-layer braided composites are evaluated by experimental, numerical and theoretical studies. The microstructure of the composites is introduced. The unit cell technique is employed to address the periodic arrangement of the structure. The volume averaging method is used in theoretical solutions while FEM with reasonable periodic boundary conditions and meshing technique in numerical simulations. Experimental studies are also conducted to verify the feasibility of the proposed models. Predicted elastic properties agree well with the experimental data, indicating the feasibility of the proposed models. Numerical evaluation is more accurate than theoretical assessment. Deformations and stress distributions of the unit cell under tension shows displacement and traction continuity, guaranteeing the rationality of the applied periodic boundary conditions. Although compression and tension modulus are close, the compressive strength only reaches 70% of the tension strength. This indicates that the composites can be weakened in compressive loading. Additionally, by analysing the micrograph of fracture faces and strain-stress curves, a brittle failure mechanism is observed both in composites under tension and compression.

  2. Theoretical and experimental NMR studies on muscimol from fly agaric mushroom (Amanita muscaria)

    Science.gov (United States)

    Kupka, Teobald; Wieczorek, Piotr P.

    2016-01-01

    In this article we report results of combined theoretical and experimental NMR studies on muscimol, the bioactive alkaloid from fly agaric mushroom (Amanita muscaria). The assignment of 1H and 13C NMR spectra of muscimol in DMSO-d6 was supported by additional two-dimensional heteronuclear correlated spectra (2D NMR) and gauge independent atomic orbital (GIAO) NMR calculations using density functional theory (DFT). The effect of solvent in theoretical calculations was included via polarized continuum model (PCM) and the hybrid three-parameter B3LYP density functional in combination with 6-311++G(3df,2pd) basis set enabled calculation of reliable structures of non-ionized (neutral) molecule and its NH and zwitterionic forms in the gas phase, chloroform, DMSO and water. GIAO NMR calculations, using equilibrium and rovibrationally averaged geometry, at B3LYP/6-31G* and B3LYP/aug-cc-pVTZ-J levels of theory provided muscimol nuclear magnetic shieldings. The theoretical proton and carbon chemical shifts were critically compared with experimental NMR spectra measured in DMSO. Our results provide useful information on its structure in solution. We believe that such data could improve the understanding of basic features of muscimol at atomistic level and provide another tool in studies related to GABA analogs.

  3. A Theoretical Framework for Studying Adolescent Contraceptive Use.

    Science.gov (United States)

    Urberg, Kathryn A.

    1982-01-01

    Presents a theoretical framework for viewing adolescent contraceptive usage. The problem-solving process is used for developmentally examining the competencies that must be present for effective contraceptive use, including: problem recognition, motivation, generation of alternatives, decision making and implementation. Each aspect is discussed…

  4. Set-theoretic methods in control

    CERN Document Server

    Blanchini, Franco

    2015-01-01

    The second edition of this monograph describes the set-theoretic approach for the control and analysis of dynamic systems, both from a theoretical and practical standpoint.  This approach is linked to fundamental control problems, such as Lyapunov stability analysis and stabilization, optimal control, control under constraints, persistent disturbance rejection, and uncertain systems analysis and synthesis.  Completely self-contained, this book provides a solid foundation of mathematical techniques and applications, extensive references to the relevant literature, and numerous avenues for further theoretical study. All the material from the first edition has been updated to reflect the most recent developments in the field, and a new chapter on switching systems has been added.  Each chapter contains examples, case studies, and exercises to allow for a better understanding of theoretical concepts by practical application. The mathematical language is kept to the minimum level necessary for the adequate for...

  5. Theoretical physics division

    International Nuclear Information System (INIS)

    Anon.

    The studies in 1977 are reviewed. In theoretical nuclear physics: nuclear structure, nuclear reactions, intermediate energy physics; in elementary particle physics: field theory, strong interactions dynamics, nucleon-nucleon interactions, new particles, current algebra, symmetries and quarks are studied [fr

  6. Adsorption of uranium composites onto saltrock oxides - experimental and theoretical study.

    Science.gov (United States)

    Ivanova, Bojidarka; Spiteller, Michael

    2014-09-01

    The study encompassed experimental mass spectrometric and theoretical quantum chemical studies on adsorption of uranium species in different oxidation states of the metal ion, and oxides of UxOy(n+) type, where x = 1 or 3, y = 2 or 8, and n = 0, 1 or 2 onto nanosize-particles of saltrock oxides MO (M = Mg(II), Ca(II), Ni(II), Co(II), Sr(II) or Ba(II)), M2Oy (M = Au(III) or Ag(I), y = 3 or 1) silicates 3Al2O3.2SiO2, natural kaolinite (Al2O2·2SiO2·2H2O), illite (K0.78Ca0.02Na0.02(Mg0.34Al1.69Fe(III)0.02)[Si3.35Al0.65]O10(OH)2·nH2O), CaSiO3, 3MgO·4SiO2,H2O, and M(1)M(2)(SiO4)X2 (M(1) = M(2) = Al or M(1) = K, M(2) = Al, X = F or Cl), respectively. The UV-MALDI-Orbitrap mass spectrometry was utilized in solid-state and semi-liquid colloidal state, involving the laser ablation at λex = 337.2 nm. The theoretical modeling and experimental design was based on chemical-, physico-chemical, physical and biological processes involving uranium species under environmental conditions. Therefore, the results reported are crucial for quality control and monitoring programs for assessment of radionuclide migration. They impact significantly the methodology for evaluation of human health risk from radioactive contamination. The study has importance for understanding the coordination and red-ox chemistry of uranium compounds as well. Due to the double nature of uranium between rare element and superconductivity like materials as well as variety of oxidation states ∈ (+1)-(+6), the there remain challenging areas for theoretical and experimental research, which are of significant importance for management of nuclear fuel cycles and waste storage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Using Mathematics, Mathematical Applications, Mathematical Modelling, and Mathematical Literacy: A Theoretical Study

    Science.gov (United States)

    Mumcu, Hayal Yavuz

    2016-01-01

    The purpose of this theoretical study is to explore the relationships between the concepts of using mathematics in the daily life, mathematical applications, mathematical modelling, and mathematical literacy. As these concepts are generally taken as independent concepts in the related literature, they are confused with each other and it becomes…

  8. Studies of the tautomeric equilibrium of 1,3-thiazolidine-2-thione: Theoretical and experimental approaches

    Energy Technology Data Exchange (ETDEWEB)

    Abbehausen, Camilla; Paiva, Raphael E.F. de [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil); Formiga, Andre L.B., E-mail: formiga@iqm.unicamp.br [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil); Corbi, Pedro P. [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Tautomeric equilibrium in solution. Black-Right-Pointing-Pointer Spectroscopic and theoretical studies. Black-Right-Pointing-Pointer UV-Vis theoretical and experimental spectra. Black-Right-Pointing-Pointer {sup 1}H NMR theoretical and experimental spectra. -- Abstract: The tautomeric equilibrium of the thione/thiol forms of 1,3-thiazolidine-2-thione was studied by nuclear magnetic resonance, infrared and ultraviolet-visible spectroscopies. Density functional theory was used to support the experimental data and indicates the predominance of the thione tautomer in the solid state, being in agreement with previously reported crystallographic data. In solution, the tautomeric equilibrium was evaluated using {sup 1}H NMR at different temperatures in four deuterated solvents acetonitrile, dimethylsulfoxide, chloroform and methanol. The equilibrium constants, K = (thiol)/(thione), and free Gibbs energies were obtained by integration of N bonded hydrogen signals at each temperature for each solvent, excluding methanol. The endothermic tautomerization is entropy-driven and the combined effect of solvent and temperature can be used to achieve almost 50% thiol concentrations in solution. The nature of the electronic transitions was investigated theoretically and the assignment of the bands was made using time-dependent DFT as well as the influence of solvent on the energy of the most important bands of the spectra.

  9. Study of network resource allocation based on market and game theoretic mechanism

    Science.gov (United States)

    Liu, Yingmei; Wang, Hongwei; Wang, Gang

    2004-04-01

    We work on the network resource allocation issue concerning network management system function based on market-oriented mechanism. The scheme is to model the telecommunication network resources as trading goods in which the various network components could be owned by different competitive, real-world entities. This is a multidisciplinary framework concentrating on the similarity between resource allocation in network environment and the market mechanism in economic theory. By taking an economic (market-based and game theoretic) approach in routing of communication network, we study the dynamic behavior under game-theoretic framework in allocating network resources. Based on the prior work of Gibney and Jennings, we apply concepts of utility and fitness to the market mechanism with an intention to close the gap between experiment environment and real world situation.

  10. Exploratory experimental and theoretical studies of cyclone gasification of wood powder

    Energy Technology Data Exchange (ETDEWEB)

    Fredriksson, Christian

    1999-11-01

    This thesis describes an exploratory experimental and theoretical study of gasification of wood powder in a cyclone gasifier. The generated gas could be used to operate a gas turbine in a combined cycle power plant. The objective has been to develop the understanding of cyclone gasification by experimental studies of the performance of a cyclone designed in principle as a separation cyclone and by comparisons between the experimental results and theoretical predictions. The experiments were carried out with commercial Swedish wood powder fuels, injected with air or steam/air mixture through two diametrically opposite tangential inlets and gasified at atmospheric pressure in cyclones of two different configurations with a volume of about 0.034 m{sup 3}. The studies show that stable gasification of this fuel can be obtained for a specific fuel feeding rate of about 5 MW/m{sup 3} cyclone volume for equivalence ratios above 0.15 and that the equivalence ratio had to be kept below about 0.4 in order to avoid material temperatures above 950 deg C. A cyclone with a short outlet pipe, designed as a conventional separation cyclone was found to give lower char conversion than a modified cyclone with a long outlet pipe. The heating value of the gas was found to be approximately 4.5 MJ/kg. The dust load in the product gas was measured to between 1000 and 2500 mg/Nm{sup 3}. It was possible to separate at least 40-60% of the potassium and 60-90% of the sodium supplied with the wood. The alkali that left the cyclone with the product gas appear to be in solid or melted phase in the unseparated char particles and consequently not vaporised during gasification. As the K and Na were assumed to remain within the particles during gasification, it was concluded that to reduce the amount of alkali metals in the product gas it would be necessary to improve the particle separation efficiency. The results of the theoretical modelling, using the existing models in the commercial software CFX

  11. Theoretical Study of Irradiation Effects in Close Binaries

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao, M.

    2009-06-01

    Full Text Available The effect of irradiation is studied in a close binary systemassuming that the secondary component is a point source, moving in a circularorbit. The irradiation effects are calculatedon the atmosphere of the primary component in a 3-dimensional Cartesiancoordinate geometry. In treating the reflection effect theoretically, the totalradiation $(S_mathrm{T}$ is obtained as the sum of the radiation of 1 the effect ofirradiation on the primary component which is calculated by using onedimensional rod model $(S_mathrm{r}$ and 2 the self radiation of the primarycomponent which is calculated by using the solution of radiative transferequation in spherical symmetry $(S_mathrm{s}$. The radiation field is estimated alongthe line of sight of the observer at infinity. It is shown how the radiationfield changes depending on the position of the secondary component.

  12. Theoretical study of the ionization of B2H5

    International Nuclear Information System (INIS)

    Curtiss, L.A.; Pople, J.A.

    1989-01-01

    Ab initio molecular orbital calculations at the G1 level of theory have been carried out on neutral B 2 H 5 radical, doubly bridged B 2 H + 5 cation, and the first triplet excited state of B 2 H + 5 . Singly bridged B 2 H 5 is 4.0 kcal/mol (without zero-point energies) more stable than doubly bridged B 2 H 5 . Based on this work and previous theoretical work on triply bridged B 2 H + 5 , ionization potentials (vertical and adiabatic) are determined for B 2 H 5 . The adiabatic ionization potentials of the two B 2 H 5 structures are 6.94 eV (singly bridged) and 7.53 eV (doubly bridged). A very large difference is found between the vertical and adiabatic ionization potentials (3.37 eV) of the singly bridged B 2 H 5 structure. The first triplet state of B 2 H + 5 is found to be 4.55 eV higher in energy than the lowest energy B 2 H + 5 cation (triply bridged). The results of this theoretical study support the interpretation of Ruscic, Schwarz, and Berkowitz of their recent photoionization measurements on B 2 H 5

  13. Theoretical study of defect properties in metals

    International Nuclear Information System (INIS)

    Sindzingre, P.

    1987-01-01

    Several characteristic properties (formation and migration enthalpies and volumes, dipole tensors, effects on shear elastic constants) of several point defects (vacancy, divacancy, interstitial, di-interstitial) in different metals: f.c.c. metals (Al, Cu, Ag, Au), h.c.p. metals (Be, Mg, Zn, Cd, Na, Co, Ti, Zr), b.c.c. metals (Li, Na, K, Rb, Cs) have been calculated. The calculated properties are evaluated from static computations performed with pair potentials derived from pseudo-potential theory (for simple or noble metals) or deduced empirically. Results are compared with available experimental data with previous theoretical works. The first part of this work where we have studied point defects properties in f.c.c. metals lead us to suggest a more convincing interpretation of X-ray scattering and elastic relation measurements concerning interstitials in Al and Cu, and a new interpretation for X-ray scattering measurements concerning di-interstitials in Al. In the second part, devoted to h.c.p. metals we are brought to propose for each studied metal the interstitial configurations which yield the best agreement with experimental results. The third part, devoted to the study of point defects in alkalin b.c.c. metals lead us to interpret self-diffusion in these metals with the assumption of a simultaneous contribution of monovacancies, divacancies and interstitials [fr

  14. Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

    Science.gov (United States)

    Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

    2016-12-01

    To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

  15. Theoretical study of diaquamalonatozinc(II) single crystal for ...

    Indian Academy of Sciences (India)

    MITESH CHAKRABORTY

    2017-11-28

    Nov 28, 2017 ... 2Laser and Spectroscopy Laboratory, Department of Applied Physics, Indian Institute of ... The aim of the present paper is to employ theoretical methods to investigate the zero field splitting .... using quantum chemistry computational models has ..... The authors are grateful to the Science and Engineer-.

  16. Theoretical and Experimental Study on Electromechanical Coupling Properties of Multihammer Synchronous Vibration System

    Directory of Open Access Journals (Sweden)

    Xin Lai

    2016-01-01

    Full Text Available Industrial simulation of real external load using multiple exciting points or increasing exciting force by synchronizing multiple exciting forces requires multiple vibration hammers to be coordinated and work together. Multihammer vibration system which consists of several hammers is a complex electromechanical system with complex electromechanical coupling. In this paper, electromechanical coupling properties of such a multihammer vibration system were studied in detail using theoretical derivation, numerical simulation, and experiment. A kinetic model of multihammer synchronous vibration system was established, and approximate expressions for electromechanical coupling strength were solved using a small parameter periodic averaging method. Basic coupling rules and reasons were obtained. Self-synchronization and frequency hopping phenomenon were also analyzed. Subsequently, numerical simulations were carried out and electromechanical coupling process was obtained for different parameters. Simulation results verify correctness of the proposed model and results. Finally, experiments were carried out, self-synchronization and frequency hopping phenomenon were both observed, and results agree well with theoretical deduction and simulation results. These results provide theoretical foundations for multihammer synchronous vibration system and its synchronous control.

  17. Theoretical studies on sRNA-mediated regulation in bacteria

    Science.gov (United States)

    Chang, Xiao-Xue; Xu, Liu-Fang; Shi, Hua-Lin

    2015-12-01

    Small RNA(sRNA)-mediated post-transcriptional regulation differs from protein-mediated regulation. Through base-pairing, sRNA can regulate the target mRNA in a catalytic or stoichiometric manner. Some theoretical models were built for comparison of the protein-mediated and sRNA-mediated modes in the steady-state behaviors and noise properties. Many experiments demonstrated that a single sRNA can regulate several mRNAs, which causes crosstalk between the targets. Here, we focus on some models in which two target mRNAs are silenced by the same sRNA to discuss their crosstalk features. Additionally, the sequence-function relationship of sRNA and its role in the kinetic process of base-pairing have been highlighted in model building. Project supported by the National Basic Research Program of China (Grant No. 2013CB834100), the National Natural Science Foundation of China (Grant Nos. 11121403 and 11274320), the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Grant No. Y4KF171CJ1), the National Natural Science Foundation for Young Scholar of China (Grant No. 11304115), and the China Postdoctoral Science Foundation (Grant No. 2013M541282).

  18. External Validity in the Study of Human Development: Theoretical and Methodological Issues

    Science.gov (United States)

    Hultsch, David F.; Hickey, Tom

    1978-01-01

    An examination of the concept of external validity from two theoretical perspectives: a traditional mechanistic approach and a dialectical organismic approach. Examines the theoretical and methodological implications of these perspectives. (BD)

  19. A theoretical framework to study variations in workplace violence experienced by emergency responders

    NARCIS (Netherlands)

    L. van Reemst (Lisa)

    2016-01-01

    markdownabstractEmergency responders are often sent to the front line and are often confronted with aggression and violence in interaction with citizens. According to previous studies, some professionals experience more workplace violence than others. In this article, the theoretical framework to

  20. A Theoretical Framework to Study Variations in Workplace Violence Experienced by Emergency Responders

    NARCIS (Netherlands)

    L. van Reemst (Lisa)

    2016-01-01

    textabstractEmergency responders are often sent to the front line and are often confronted with aggression and violence in inter- action with citizens. According to previous studies, some professionals experience more workplace violence than others. In this article, the theoretical framework to

  1. Theoretical study of the structure and the reactivity of lanthanides and actinides complexes: Activation of small molecules

    International Nuclear Information System (INIS)

    Castro, Ludovic

    2012-01-01

    This PhD thesis presents a theoretical study of the structure and the reactivity of organometallic complexes of lanthanides and actinides at the DFT level. After a general introduction of the methods of theoretical chemistry used for the modelling of organometallic reactivity, a study of the participation of 5f electrons in uranium(IV) reactivity is presented. The results show that the large core ECP can be used safely in order to treat the actinide and so that 5f electrons can be treated implicitly. Then, the reactivity of uranium(III) complexes with CO 2 and other analogous molecules is studied via multiple examples from the literature. These studies show that the steric nature of the ligands is very important and controls the reactivity. This study is then extended to samarium(II) complex. Eventually, the reactivity of a hydride complex of cerium(III) with MeOSO 2 Me is investigated and theoretical results are compared with experimental observations. (author) [fr

  2. Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

    International Nuclear Information System (INIS)

    Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel

    2012-01-01

    Highlights: ► We study properties of Ph 2 Tz and (PhTz) n Ph as candidates for organic electronics. ► The synthesis of Ph 2 Tz was performed through a modified Pinner-type reaction. ► IR/Raman spectra allowed to conclude that Ph 2 Tz is nearly planar in liquid phase. ► Electronic structure was studied by UV–Vis/TD-DFT methods in different solvents. ► Bandgap, E LUMO , electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph 2 Tz) and some oligomeric derivatives. Ph 2 Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV–Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

  3. Theoretical studies of ionic conductivity of crosslinked chitosan membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Ernesto Lopez [Programa de Ingenieria Molecular y Nuevos Materiales, Universidad Autonoma de la Ciudad de Mexico, Fray Servando Teresa de Mier 92, 1er. Piso, Col Centro, Mexico D.F. CP 06080 (Mexico); Oviedo-Roa, R.; Contreras-Perez, Gustavo; Martinez-Magadan, Jose Manuel [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte 152, Col. San Bartolo Atepehuacan, CP 07730 Mexico D.F. (Mexico); Castillo-Alvarado, F.L. [Escuela Superior de Fisica y Matematicas del Instituto Politecnico Nacional, Edificio 9 de la UPALM, Colonia Lindavista, Mexico D.F. CP 07738 (Mexico)

    2010-11-15

    Ionic conductivity of crosslinked chitosan membranes was studied using techniques of molecular modeling and simulation. The COMPASS force field was used. The simulation allows the description of the mechanism of ionic conductivity along the polymer matrix. The theoretical results obtained are compared with experimental results for chitosan membranes. The analysis suggests that the conduction mechanism is portrayed by the overlapping large Polaron tunneling model. In addition, when the chitosan membrane was crosslinked with an appropriate degree of crosslinking its ionic conductivity, at room temperature, was increased by about one order of magnitude. The chitosan membranes can be used as electrolytes in solid state batteries, electric double layer capacitors and fuel cells. (author)

  4. Coulomb drag in anisotropic systems: a theoretical study on a double-layer phosphorene

    NARCIS (Netherlands)

    Saberi-Pouya, S.; Vazifehshenas, T.; Farmanbar Gelepordsari, M.; Salavati-Fard, T.

    2016-01-01

    We theoretically study the Coulomb drag resistivity in a double-layer electron system with highly anisotropic parabolic band structure using Boltzmann transport theory. As an example, we consider a double-layer phosphorene on which we apply our formalism. This approach, in principle, can be tuned

  5. A theoretical study on the photoionization of the valence orbitals of phosphine

    Directory of Open Access Journals (Sweden)

    Nascimento Edmar M.

    2006-01-01

    Full Text Available We report a theoretical study on the photoionization of phosphine in the static-exchange level and frozen core approximation, using the method of continued fractions. The main subject of the present study is to investigate in which extent the Hartree-Fock description of the target applied to molecular photoionization is valid. Also, the role played by multichannel coupling is analysed. Our study shows that single-channel Hartree-Fock calculations can provide reliable results except for photon energies near the photoionization threshold.

  6. Coordination to transition metal surfaces : a theoretical study

    NARCIS (Netherlands)

    Santen, van R.A.

    1985-01-01

    A theoretical framework is developed that describes the chemisorption of CO to transition metal surfaces analogous to the HOMO-LUMO concept of MO theory. An explanation is given for the exptl. observation that CO adsorbs on top at the (111), face of Pt, but bridge at the (111) face of Ni. One is due

  7. Theoretical study of electronic absorption spectroscopy of propadienylidene molecule vis-â-vis the observed diffuse interstellar bands

    International Nuclear Information System (INIS)

    Reddy, Samala Nagaprasad; Mahapatra, S.

    2012-01-01

    Highlights: ► Theoretical study of spectroscopy and dynamics of electronically excited l-C 3 H 2 . ► Construction of ab initio electronic potential energy and diabatic coupling surfaces. ► First principles study of nuclear dynamics on excited electronic states. ► Findings reveal l-C 3 H 2 is a potential molecular carrier of diffuse interstellar bands. ► Electronically excited l-C 3 H 2 decays by ultrafast nonradiative internal conversion. -- Abstract: Observation of broad and diffuse interstellar bands (DIBs) at 4881 Å and 5440 Å assigned to the optical absorption spectrum of Y-shaped propadienylidene (H 2 C=C=C:) molecule is theoretically examined in this paper. This molecule apparently absorbs in the same wavelength region as the observed DIBs and was suggested to be a potential carrier of these DIBs. This assignment mostly relied on the experimental data from radioastronomy and laboratory measurements. Motivated by these available experimental data we attempt here a theoretical study and investigate the detailed electronic structure and nuclear dynamics underlying the electronic absorption bands of propadienylidene molecule. Our results show that this molecule indeed absorbs in the wavelength region of the recorded DIBs. Strong nonadiabatic coupling between its energetically low-lying electronic states plays major role, initiates ultrafast internal conversion and contributes to the spectral broadening. Theoretical findings are finally compared with the available experimental and theoretical data and discussed in connection with the recorded DIBs.

  8. Theoretical study on the inverse modeling of deep body temperature measurement

    International Nuclear Information System (INIS)

    Huang, Ming; Chen, Wenxi

    2012-01-01

    We evaluated the theoretical aspects of monitoring the deep body temperature distribution with the inverse modeling method. A two-dimensional model was built based on anatomical structure to simulate the human abdomen. By integrating biophysical and physiological information, the deep body temperature distribution was estimated from cutaneous surface temperature measurements using an inverse quasilinear method. Simulations were conducted with and without the heat effect of blood perfusion in the muscle and skin layers. The results of the simulations showed consistently that the noise characteristics and arrangement of the temperature sensors were the major factors affecting the accuracy of the inverse solution. With temperature sensors of 0.05 °C systematic error and an optimized 16-sensor arrangement, the inverse method could estimate the deep body temperature distribution with an average absolute error of less than 0.20 °C. The results of this theoretical study suggest that it is possible to reconstruct the deep body temperature distribution with the inverse method and that this approach merits further investigation. (paper)

  9. Theoretical foundations of international migration process studies: analysis of key migration theories development

    Directory of Open Access Journals (Sweden)

    Shymanska K.V.

    2017-03-01

    Full Text Available The need for transformation of Ukraine's migration policy based on globalized world development trends and in response to the challenges of European integration transformations causes the need of researching the theoretical and methodological basis of migration studies, and the regulations of existing theories of international migration. The bibliometric analysis of scientific publications on international migration in cites indexes found that the recent researches on these problems acquire interdisciplinary character. It necessitates the transformation of migration study approaches basing on economic, social, institutional theories and concepts synthesis. The article is devoted to the study of theoretical regulations of existing international migration theories in the context of the evolution of scientists’ views on this phenomenon. The author found that the existing theories of international migration should be divided into three categories (microeconomic, macroeconomic, globalizational that contributes to their understanding in the context of implementation possibilities in migrational public administration practice. It allows to determine the theories which should be used for Ukrainian state migration policy constructing and eliminating or reducing the external migration negative effects.

  10. Annual Report 2013-2014: Theoretical Studies of Nerve Agents Adsorbed on Surfaces

    Science.gov (United States)

    2014-07-08

    magnesium oxide. Journal of Physical Chemistry B 2004, 108, 5294-5303. 7. Michalkova, A.; Paukku, Y.; Majumdar, D.; Leszczynski, J., Theoretical study...M.; Hyre, A. M., Ultraviolet Raman Spectra and Cross-Sections of the G-series Nerve Agents. Applied Spectroscopy 2008, 62, 1078-1083. 12. DaBell...mol) 24 2.3 Raman and DFT study of pyrocarbonate 2.3.1 In-situ Raman spectroscopic investigation The Li2CO3 and Na2CO3 eutectic mixture (52:48

  11. Experimental and theoretical studies on a novel helical architecture ...

    Indian Academy of Sciences (India)

    aKey Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory ... bInstitute for Computation in Molecular and Material Science, School of Chemical Engineering, Nanjing ... mental and theoretical points of view is still largely.

  12. The structure, vibrational spectra and nonlinear optical properties of the L-lysine × tartaric acid complex—Theoretical studies

    Science.gov (United States)

    Drozd, M.; Marchewka, M. K.

    2006-05-01

    The room temperature X-ray studies of L-lysine × tartaric acid complex are not unambiguous. The disorder of three atoms of carbon in L-lysine molecule is observed. These X-ray studies are ambiguous. The theoretical geometry study performed by DFT methods explain the most doubts which are connected with crystallographic measurements. The theoretical vibrational frequencies and potential energy distribution (PED) of L-lysine × tartaric acid were calculated by B3LYP method. The calculated frequencies were compared with experimental measured IR spectra. The complete assignment of the bands has been made on the basis of the calculated PED. The restricted Hartee-Fock (RHF) methods were used for calculation of the hyperpolarizability for investigated compound. The theoretical results are compared with experimental value of β.

  13. Theoretical studies on the α decay half-lives of hyper and normal ...

    Indian Academy of Sciences (India)

    The α decay half-lives of hyper and normal isotopes of Po nuclei are studied in the present work. The inclusion of Λ – N interaction changes the half-life for α decay. The theoretical predictions on the α decay half-lives of normal Po isotopes are compared with experimental results and are seen to be matching well with each ...

  14. Reactor oscillator project - Theoretical study; operation problems; choice of the ionization chamber

    International Nuclear Information System (INIS)

    Lolic, B.; Markovic, V.

    1961-01-01

    Theoretical study of the reactor operator covers methods of the danger coefficient and the method based on measuring the phase angle. Operation with the reactor oscillator describes measurement of the cross section and resonance integral, measurement of the fissionable materials properties, measurement of impurities in the graphite sample. A separate chapter is devoted to the choice of the appropriate ionization chamber

  15. Theoretical study on device efficiency of pulsed liquid jet pump

    International Nuclear Information System (INIS)

    Gao Chuanchang; Lu Hongqi; Wang Shicheng; Cheng Mingchuan

    2001-01-01

    The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries

  16. The social embeddedness of media use - Action theoretical contributions to the study of TV use in everyday life

    NARCIS (Netherlands)

    Westerik, H.

    2009-01-01

    Scholars in the field of communication research have extensively studied television viewing in general and watching television news in particular. The book looks at the subject from an integrative theoretical perspective. Based on Schutzean sociology and action theoretical approaches to media use,

  17. Theoretical study of structure of electric field in helical toroidal plasmas

    International Nuclear Information System (INIS)

    Toda, S.; Itoh, K.

    2001-06-01

    A set of transport equations is analyzed, including the bifurcation of the electric field. The structure of the electric field is studied by use of the theoretical model for the anomalous transport diffusivities. The steep gradient of the electric field is obtained at the electric domain. The suppression of the anomalous transport diffusivity is studied in the presence of the strong shear of the electric field. The hard transition with the multiple ambipolar solutions is examined in the structure of the radial electric field. The details of the structure of the electric domain interface are investigated. (author)

  18. Theoretical and observational studies of stellar activity

    International Nuclear Information System (INIS)

    Schmitt, J.H.M.M.

    1984-01-01

    In the theoretical part of this thesis, doubly-diffusive MHD instabilities are studied as a means of breaking up a diffuse magnetic field at the bottom of the solar convection zone. The analysis is linear and local, and assumes short meridional wavelengths; the effects of rotation and diffusion of vorticity, magnetic fields and heat are included. Results show that the instability depends sensitively on the temperature stratification, but rather insensitively on the assumed magnetic field configuration; instability time scales considerably less than the solar cycle period can be easily obtained. In the observational part of the thesis, results are reported of a survey of the x-ray emission of stars with shallow connection zones to study the onset of convection and dynamo activity along the main sequence. Complications arising from stellar multiplicity are discussed extensively; it is demonstrated that binaries have statistically higher x-ray luminosities; and it is shown that physical parameters can only be deduced from single stars. It is further shown that the x-ray luminosities of stars with spectral type in the color range 0.1 less than or equal to B. V less than or equal to 0.5 increase rapidly, whereas stars with B. V approx. 0.0 appear to have no intrinsic x-ray emission at presently detectable levels

  19. Theoretical Study of the Diastereofacial Isomers of Aldrin and Dieldrin

    Directory of Open Access Journals (Sweden)

    Zoran Zdravkovski

    2006-02-01

    Full Text Available The Diels-Alder reaction of hexachlorocyclopentadiene with norbornadiene givesaldrin but theoretically three other diastereofacial isomers are possible. On oxidation theseisomers can generate eight adducts one of which is known as dieldrin. All these, as well asthe corresponding reactions with hexafluorocyclopenadiene were studied by semiempirical(AM1 and PM3 and hybrid density functional (B3LYP methods. Besides the energy levels,the transition states were calculated for the reactions leading to the diastereofacial isomers ofaldrin, which indicate that aldrin is the favored product of the reaction both fromthermodynamic and kinetic point of view.

  20. Optical and theoretical studies of giant clouds in spiral galaxies

    International Nuclear Information System (INIS)

    Elmegreen, B.G.; Elmegreen, D.M.

    1980-01-01

    An optical study of four spiral galaxies, combined with radiative transfer models for transmitted and scattered light, has led to a determination of the opacities and masses of numerous dark patches and dust lanes that outline spiral structure. The observed compression factors for the spiral-like dust lanes are in accord with expectations from the theory of gas flow in spiral density waves. Several low density (10 2 cm -3 ) clouds containing 10 6 to 10 7 solar masses were also studied. These results are discussed in terms of recent theoretical models of cloud and star formation in spiral galaxies. The long-term evolution of giant molecular clouds is shown to have important consequences for the positions and ages of star formation sites in spiral arms. (Auth.)

  1. [Participatory education and the development of critical reading in teachers theoretical texts. Multicenter study].

    Science.gov (United States)

    Leyva-González, Félix Arturo; Leo-Amador, Guillermo Enrique; Viniegra-Velázquez, Leonardo; Degollado-Bardales, Lilia; Zavala-Arenas, Jesús Arturo; González-Cobos, Roberto Palemón; Valencia-Sánchez, Jesús Salvador; Leyva-Salas, César Arturo; Angulo-Bernal, Sonia Elizabeth; Gómez-Arteaga, Gress Marissell

    2010-01-01

    Determine what the relationship between participation in classroom of students attending courses at the Educational Research and Teacher Education (CIEFD's) and the development of proficiency in critical reading of theoretical texts in education. Intervention study, multicenter students (medical specialist) level Diploma in teaching methodology (DMDN) 1 and 2 (n=46 n=29) of the six CIEFD's (DF Siglo XXI, Mexico City La Raza, Nuevo Leon, Sonora, Puebla and Veracruz), period: March to August 2007 and a Masters in education (n=9, generation 2007-2008). Two instruments were constructed that evaluated the participation variables and critical reading of theoretical texts in education, conceptual validity; content and reliability were assessed by experts in education research. The educational intervention was in the form of seminars (three times a week in DMDN 1 and twice weekly in DMDN 2 and Masters). Participation was assessed halfway through the course and on completion, critical reading at the beginning as well as the end. Statistically significant associations were observed in DMDN 1 (four Centers) and the Masters, but not DMDN 2. In this investigation some of the theoretical proposals of the participatory education were recreated, starting from the analysis of our results. In some centers and in the masters, strengthening participation in this educational intervention is related to the development of critical reading of theoretical texts in education.

  2. Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Moral, Monica; Garcia, Gregorio [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Penas, Antonio [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Garzon, Andres; Granadino-Roldan, Jose M. [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Melguizo, Manuel [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Fernandez-Gomez, Manuel, E-mail: mfg@ujaen.es [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer We study properties of Ph{sub 2}Tz and (PhTz){sub n}Ph as candidates for organic electronics. Black-Right-Pointing-Pointer The synthesis of Ph{sub 2}Tz was performed through a modified Pinner-type reaction. Black-Right-Pointing-Pointer IR/Raman spectra allowed to conclude that Ph{sub 2}Tz is nearly planar in liquid phase. Black-Right-Pointing-Pointer Electronic structure was studied by UV-Vis/TD-DFT methods in different solvents. Black-Right-Pointing-Pointer Bandgap, E{sub LUMO}, electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph{sub 2}Tz) and some oligomeric derivatives. Ph{sub 2}Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

  3. An experimental and theoretical study of reaction mechanisms between nitriles and hydroxylamine.

    Science.gov (United States)

    Vörös, Attila; Mucsi, Zoltán; Baán, Zoltán; Timári, Géza; Hermecz, István; Mizsey, Péter; Finta, Zoltán

    2014-10-28

    The industrially relevant reaction between nitriles and hydroxylamine yielding amidoximes was studied in different molecular solvents and in ionic liquids. In industry, this procedure is carried out on the ton scale in alcohol solutions and the above transformation produces a significant amount of unexpected amide by-product, depending on the nature of the nitrile, which can cause further analytical and purification issues. Although there were earlier attempts to propose mechanisms for this transformation, the real reaction pathway is still under discussion. A new detailed reaction mechanistic explanation, based on theoretical and experimental proof, is given to augment the former mechanisms, which allowed us to find a more efficient, side-product free procedure. Interpreting the theoretical results obtained, it was shown that the application of specific imidazolium, phosphonium and quaternary ammonium based ionic liquids could decrease simultaneously the reaction time while eliminating the amide side-product, leading to the targeted product selectively. This robust and economic procedure now affords a fast, selective amide free synthesis of amidoximes.

  4. Protonation of caffeine: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, Hamed [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Tabrizchi, Mahmoud, E-mail: m-tabriz@cc.iut.ac.ir [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Farrokhpour, Hossein [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2013-03-29

    Highlights: ► Protonation of caffeine was examined by ion mobility spectrometry equipped with two ionization sources. ► Experimental and theoretical evidence was collected to assign the observed peaks to caffeine related ionic species. ► A new concept of “internal proton affinity”, the protonation tendency for each atom in a molecule, was defined. - Abstract: Protonation of caffeine was examined by ion mobility spectrometry equipped with two ionization sources, corona discharge (CD) and UV photoionization. Three peaks were observed in ion mobility spectrum by simultaneously running the two ionization sources. Experimental and theoretical evidence was collected to link the observed peaks to caffeine related ionic species. One peak was attributed to the M{sup +} ion while the other two were assigned to different protonated isomers of caffeine. In the case of CD ionization source, it was observed that different sites of caffeine compete for protonation and their relative intensities, depends on the sample concentration as well as the nature of the reactant ions. The new concept of “internal proton affinity” (IPA) was defined to express the tendency of holding the added proton for each atom in a molecule.

  5. Protonation of caffeine: A theoretical and experimental study

    International Nuclear Information System (INIS)

    Bahrami, Hamed; Tabrizchi, Mahmoud; Farrokhpour, Hossein

    2013-01-01

    Highlights: ► Protonation of caffeine was examined by ion mobility spectrometry equipped with two ionization sources. ► Experimental and theoretical evidence was collected to assign the observed peaks to caffeine related ionic species. ► A new concept of “internal proton affinity”, the protonation tendency for each atom in a molecule, was defined. - Abstract: Protonation of caffeine was examined by ion mobility spectrometry equipped with two ionization sources, corona discharge (CD) and UV photoionization. Three peaks were observed in ion mobility spectrum by simultaneously running the two ionization sources. Experimental and theoretical evidence was collected to link the observed peaks to caffeine related ionic species. One peak was attributed to the M + ion while the other two were assigned to different protonated isomers of caffeine. In the case of CD ionization source, it was observed that different sites of caffeine compete for protonation and their relative intensities, depends on the sample concentration as well as the nature of the reactant ions. The new concept of “internal proton affinity” (IPA) was defined to express the tendency of holding the added proton for each atom in a molecule

  6. Theoretical and experimental study of non-monotonous effects

    International Nuclear Information System (INIS)

    Delforge, J.

    1977-01-01

    In recent years, the study of the effects of low dose rates has expanded considerably, especially in connection with current problems concerning the environment and health physics. After having made a precise definition of the different types of non-monotonous effect which may be encountered, for each the main experimental results known are indicated, as well as the principal consequences which may be expected. One example is the case of radiotherapy, where there is a chance of finding irradiation conditions such that the ratio of destructive action on malignant cells to healthy cells is significantly improved. In the second part of the report, the appearance of these phenomena, especially at low dose rates are explained. For this purpose, the theory of transformation systems of P. Delattre is used as a theoretical framework. With the help of a specific example, it is shown that non-monotonous effects are frequently encountered, especially when the overall effect observed is actually the sum of several different elementary effects (e.g. in survival curves, where death may be due to several different causes), or when the objects studied possess inherent kinetics not limited to restoration phenomena alone (e.g. cellular cycle) [fr

  7. A Combined Theoretical and Experimental Study for Silver Electroplating

    Science.gov (United States)

    Liu, Anmin; Ren, Xuefeng; An, Maozhong; Zhang, Jinqiu; Yang, Peixia; Wang, Bo; Zhu, Yongming; Wang, Chong

    2014-01-01

    A novel method combined theoretical and experimental study for environmental friendly silver electroplating was introduced. Quantum chemical calculations and molecular dynamic (MD) simulations were employed for predicting the behaviour and function of the complexing agents. Electronic properties, orbital information, and single point energies of the 5,5-dimethylhydantoin (DMH), nicotinic acid (NA), as well as their silver(I)-complexes were provided by quantum chemical calculations based on density functional theory (DFT). Adsorption behaviors of the agents on copper and silver surfaces were investigated using MD simulations. Basing on the data of quantum chemical calculations and MD simulations, we believed that DMH and NA could be the promising complexing agents for silver electroplating. The experimental results, including of electrochemical measurement and silver electroplating, further confirmed the above prediction. This efficient and versatile method thus opens a new window to study or design complexing agents for generalized metal electroplating and will vigorously promote the level of this research region.

  8. A Combined Theoretical and Experimental Study for Silver Electroplating

    Science.gov (United States)

    Liu, Anmin; Ren, Xuefeng; An, Maozhong; Zhang, Jinqiu; Yang, Peixia; Wang, Bo; Zhu, Yongming; Wang, Chong

    2014-01-01

    A novel method combined theoretical and experimental study for environmental friendly silver electroplating was introduced. Quantum chemical calculations and molecular dynamic (MD) simulations were employed for predicting the behaviour and function of the complexing agents. Electronic properties, orbital information, and single point energies of the 5,5-dimethylhydantoin (DMH), nicotinic acid (NA), as well as their silver(I)-complexes were provided by quantum chemical calculations based on density functional theory (DFT). Adsorption behaviors of the agents on copper and silver surfaces were investigated using MD simulations. Basing on the data of quantum chemical calculations and MD simulations, we believed that DMH and NA could be the promising complexing agents for silver electroplating. The experimental results, including of electrochemical measurement and silver electroplating, further confirmed the above prediction. This efficient and versatile method thus opens a new window to study or design complexing agents for generalized metal electroplating and will vigorously promote the level of this research region. PMID:24452389

  9. Electrochemistry of chlorogenic acid: experimental and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Namazian, Mansoor [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of)]. E-mail: namazian@yazduni.ac.ir; Zare, Hamid R. [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of)

    2005-08-10

    Cyclic voltammetry, chronoamperometry and rotating disk electrode voltammetry as well as quantum chemical methods, are used for electrochemical study of chlorogenic acid, as an important biological molecule. The standard formal potential, diffusion coefficient, and heterogeneous electron transfer rate constant of chlorogenic acid in aqueous solution are investigated. Acidic dissociation constant of chlorogenic acid is also obtained. Quantum mechanical calculations on oxidation of chlorogenic acid in aqueous solution, using density functional theory are presented. The change of Gibbs free energy and entropy of oxidation of chlorogenic acid are calculated using thermochemistry calculations. The calculations in aqueous solution are carried out with the use of polarizable continuum solvation method. Theoretical standard electrode potential of chlorogenic acid is achieved to be 0.580 V versus standard calomel electrode (SCE) which is in agreement with the experimental value of 0.617 V obtained experimentally in this work. The difference is consistent with the values we previously reported for other quinone derivatives.

  10. An Experimental and Theoretical Study on Cavitating Propellers.

    Science.gov (United States)

    1982-10-01

    34 And Identfyp eV &to" nMeeJ cascade flow theoretical supercavitating flow performance prediction method partially cavitating flow supercavitating ...the present work was to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of...operating conditions. Due to the complex nature of the flow phenomena, a lifting line theory sirply combined with the two-dimensional supercavitating

  11. Theoretical solid state physics

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Research activities at ORNL in theoretical solid state physics are described. Topics covered include: surface studies; particle-solid interactions; electronic and magnetic properties; and lattice dynamics

  12. Studies in Theoretical and Applied Statistics

    CERN Document Server

    Pratesi, Monica; Ruiz-Gazen, Anne

    2018-01-01

    This book includes a wide selection of the papers presented at the 48th Scientific Meeting of the Italian Statistical Society (SIS2016), held in Salerno on 8-10 June 2016. Covering a wide variety of topics ranging from modern data sources and survey design issues to measuring sustainable development, it provides a comprehensive overview of the current Italian scientific research in the fields of open data and big data in public administration and official statistics, survey sampling, ordinal and symbolic data, statistical models and methods for network data, time series forecasting, spatial analysis, environmental statistics, economic and financial data analysis, statistics in the education system, and sustainable development. Intended for researchers interested in theoretical and empirical issues, this volume provides interesting starting points for further research.

  13. [Social determinants of odontalgia in epidemiological studies: theoretical review and proposed conceptual model].

    Science.gov (United States)

    Bastos, João Luiz Dornelles; Gigante, Denise Petrucci; Peres, Karen Glazer; Nedel, Fúlvio Borges

    2007-01-01

    The epidemiological literature has been limited by the absence of a theoretical framework reflecting the complexity of causal mechanisms for the occurrence of health phenomena / disease conditions. In the field of oral epidemiology, such lack of theory also prevails, since dental caries the leading topic in oral research has been often studied through a biological and reductionist viewpoint. One of the most important consequences of dental caries is dental pain (odontalgia), which has received little attention in studies with sophisticated theoretical models and powerful designs to establish causal relationships. The purpose of this study is to review the scientific literature on the determinants of odontalgia and to discuss theories proposed for the explanation of the phenomenon. Conceptual models and emerging theories on the social determinants of oral health are revised, in an attempt to build up links with the bio-psychosocial pain model, proposing a more elaborate causal model for odontalgia. The framework suggests causal pathways between social structure and oral health through material, psychosocial and behavioral pathways. Aspects of the social structure are highlighted in order to relate them to odontalgia, stressing their importance in discussions of causal relationships in oral health research.

  14. Theoretical and experimental studies on the daily accumulative heat gain from cool roofs

    International Nuclear Information System (INIS)

    Qin, Yinghong; Zhang, Mingyi; Hiller, Jacob E.

    2017-01-01

    Cool roofs are gaining popularity as passive building cooling techniques, but the correlation between energy savings and rooftop albedo has not been understood completely. Here we theoretically model the daily accumulative inward heat (DAIH) from building roofs with different albedo values, correlating the heat gain of the building roof to both the rooftop albedo and the incident solar radiation. According to this model, the DAIH increases linearly with the daily zenith solar radiation, but decreases linearly with the rooftop albedo. A small building cell was constructed to monitor the heat gain of the building under the conditions of non-insulated and insulated roofs. The observational DAIH is highly coincident with the theoretical one, validating the theoretical model. It was found that insulating the roof, increasing the rooftop albedo, or both options can effectively curtail the heat gain in buildings during the summer season. The proposed theoretical model would be a powerful tool for evaluating the heat gain of the buildings and estimating the energy savings potential of high-reflective cool roofs. - Highlights: • Daily accumulative heat gain from a building roof is theoretically modeled. • Daily accumulative heat gain from a building roof increases linearly with rooftop absorptivity. • Increasing the roof insulation tapers the effect of the rooftop absorptivity. • The theoretical model is powerful for estimating energy savings of reflective roofs.

  15. Theoretical study on perylene derivatives as fluorescent sensors for amines

    Science.gov (United States)

    Lathiotakis, Nektarios N.; Kerkines, Ioannis S. K.; Theodorakopoulos, Giannoula; Petsalakis, Ioannis D.

    2018-01-01

    A theoretical study is presented on perylene diimide (PDI) and perylene monoimide (PMI) and their action as sensors of amines in solution. Density functional theory (DFT) and Time dependent DFT (TDDFT) calculations are carried out on complexes of PDI and PMI with aniline in THF solution. The optimized geometries for the complexes have aniline lying parallel above the perylene at 3.15 Å and with binding energy of 0.53 eV in the ground state. The results on the excited states are consistent with a photoinduced electron transfer (PET) mechanism. The effective aniline-perylene distance resulting from a Mulliken's approach is 3.61 Å.

  16. Experimental and theoretical study of the energy loss of C and O in Zn

    Energy Technology Data Exchange (ETDEWEB)

    Cantero, E. D.; Lantschner, G. H.; Arista, N. R. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche (Argentina); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Buenos Aires (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Behar, M.; Fadanelli, R. C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, Porto Alegre-RS (Brazil)

    2011-07-15

    We present a combined experimental-theoretical study of the energy loss of C and O ions in Zn in the energy range 50-1000 keV/amu. This contribution has a double purpose, experimental and theoretical. On the experimental side, we present stopping power measurements that fill a gap in the literature for these projectile-target combinations and cover an extended energy range, including the stopping maximum. On the theoretical side, we make a quantitative test on the applicability of various theoretical approaches to calculate the energy loss of heavy swift ions in solids. The description is performed using different models for valence and inner-shell electrons: a nonperturbative scattering calculation based on the transport cross section formalism to describe the Zn valence electron contribution, and two different models for the inner-shell contribution: the shellwise local plasma approximation (SLPA) and the convolution approximation for swift particles (CasP). The experimental results indicate that C is the limit for the applicability of the SLPA approach, which previously was successfully applied to projectiles from H to B. We find that this model clearly overestimates the stopping data for O ions. The origin of these discrepancies is related to the perturbative approximation involved in the SLPA. This shortcoming has been solved by using the nonperturbative CasP results to describe the inner-shell contribution, which yields a very good agreement with the experiments for both C and O ions.

  17. Studies in theoretical high energy particle physics

    International Nuclear Information System (INIS)

    Aratyn, H.; Brekke, L.; Keung, Wai-Yee; Sukhatme, U.

    1993-01-01

    Theoretical work on the following topics is briefly summarized: symmetry structure of conformal affine Toda model and KP hierarchy; solitons in the affine Toda and conformal affine Toda models; classical r-matrices and Poisson bracket structures on infinite-dimensional groups; R-matrix formulation of KP hierarchies and their gauge equivalence; statistics of particles and solitons; charge quantization in the presence of an Alice string; knotting and linking of nonabelian flux; electric dipole moments; neutrino physics in gauge theories; CP violation in the high energy colliders; supersymmetric quantum mechanics; parton structure functions in nuclei; dual parton model. 38 refs

  18. Toward a Theoretical Framework for Studying Climate Change Policies: Insights from the Case Study of Singapore

    Directory of Open Access Journals (Sweden)

    Ai Sian Ng

    2017-07-01

    Full Text Available The world decided in December 2015 to take actions to reduce global warming. To contribute toward this goal, this research examines possible policy levers for inclusion in the climate change ratification plan. A case study of the measures taken by the Republic of Singapore, a low-lying 719.2 km2 island without natural resources in Asia, is conducted. Being vulnerable to climate change impact and yet having to balance her people’s needs and economic progress with limited resources, the measures taken by this small country could offer policy insights for small states and states without access to alternative energy sources. This research analyzes the online policy documents posted by eleven organizations to answer the main research question of identifying policy levers as theoretical constructs to form a framework that can be used to study climate change policies. A qualitative data analysis software, QSR NVivo 10, is used to classify the proposed nodes developed by the researchers using a system perspective integrating the insights from the key international climate change frameworks with the theoretical concepts from the model of pro-environmental behavior. The findings can offer insights toward developing a new contextual influence framework, which can help strengthen policy development and outcome measurement.

  19. Theoretical study of heat transfer with moving phase-change interface in thawing of frozen food

    International Nuclear Information System (INIS)

    Leung, M; Ching, W H; Leung, D Y C; Lam, G C K

    2005-01-01

    A theoretical solution was obtained for a transient phase-change heat transfer problem in thawing of frozen food. In the physical model, a sphere originally at a uniform temperature below the phase-change temperature is suddenly immersed in a fluid at a temperature above the phase-change temperature. As the body temperature increases, the phase-change interface will be first formed on the surface. Subsequently, the interface will absorb the latent heat and move towards the centre until the whole body undergoes complete phase change. In the mathematical formulation, the nonhomogeneous problem arises from the moving phase-change interface. The solution in terms of the time-dependent temperature field was obtained by use of Green's function. A one-step Newton-Raphson method was specially designed to solve for the position of the moving interface to satisfy the interface condition. The theoretical results were compared with numerical results generated by a finite difference model and experimental measurements collected from a cold water thawing process. As a good agreement was found, the theoretical solution developed in this study was verified numerically and experimentally. Besides thawing of frozen food, there are many other practical applications of the theoretical solution, such as food freezing, soil freezing/thawing, metal casting and bath quenching heat treatment, among others

  20. Theoretical study of heat transfer with moving phase-change interface in thawing of frozen food

    Science.gov (United States)

    Leung, M.; Ching, W. H.; Leung, D. Y. C.; Lam, G. C. K.

    2005-02-01

    A theoretical solution was obtained for a transient phase-change heat transfer problem in thawing of frozen food. In the physical model, a sphere originally at a uniform temperature below the phase-change temperature is suddenly immersed in a fluid at a temperature above the phase-change temperature. As the body temperature increases, the phase-change interface will be first formed on the surface. Subsequently, the interface will absorb the latent heat and move towards the centre until the whole body undergoes complete phase change. In the mathematical formulation, the nonhomogeneous problem arises from the moving phase-change interface. The solution in terms of the time-dependent temperature field was obtained by use of Green's function. A one-step Newton-Raphson method was specially designed to solve for the position of the moving interface to satisfy the interface condition. The theoretical results were compared with numerical results generated by a finite difference model and experimental measurements collected from a cold water thawing process. As a good agreement was found, the theoretical solution developed in this study was verified numerically and experimentally. Besides thawing of frozen food, there are many other practical applications of the theoretical solution, such as food freezing, soil freezing/thawing, metal casting and bath quenching heat treatment, among others.

  1. Experimental and theoretical studies of near-ground acoustic radiation propagation in the atmosphere

    Science.gov (United States)

    Belov, Vladimir V.; Burkatovskaya, Yuliya B.; Krasnenko, Nikolai P.; Rakov, Aleksandr S.; Rakov, Denis S.; Shamanaeva, Liudmila G.

    2017-11-01

    Results of experimental and theoretical studies of the process of near-ground propagation of monochromatic acoustic radiation on atmospheric paths from a source to a receiver taking into account the contribution of multiple scattering on fluctuations of atmospheric temperature and wind velocity, refraction of sound on the wind velocity and temperature gradients, and its reflection by the underlying surface for different models of the atmosphere depending the sound frequency, coefficient of reflection from the underlying surface, propagation distance, and source and receiver altitudes are presented. Calculations were performed by the Monte Carlo method using the local estimation algorithm by the computer program developed by the authors. Results of experimental investigations under controllable conditions are compared with theoretical estimates and results of analytical calculations for the Delany-Bazley impedance model. Satisfactory agreement of the data obtained confirms the correctness of the suggested computer program.

  2. Overview. Department of Theoretical Physics. Section 4

    Energy Technology Data Exchange (ETDEWEB)

    Kwiecinski, J. [Institute of Nuclear Physics, Cracow (Poland)

    1995-12-31

    Research activity of the Department of the Theoretical Physics spans a wide variety of problems in theoretical high-energy and elementary particle physics, theoretical nuclear physics, theory of the nuclear matter, quark gluon plasma and relativistic heavy-ion collisions, theoretical astrophysics, as well as general physics. Theoretical research in high energy and elementary particle physics is concentrated on the theory of deep inelastic lepton scattering in the region of low x and its phenomenological implication for the ep collider HERA at DESY, on the theory of nonleptonic decays of hadrons, and on low energy {pi}{pi} and K-anti-K interactions and scalar meson spectroscopy. The activity in the theory of relativistic heavy-ion collisions is focused on the study of quark condensate fluctuations, on the analysis of critical scattering near the chiral phase transition, and on Bose-Einstein correlation in heavy-ion collisions. Theoretical studies in nuclear physics and in theory of nuclear matter concern analysis of models, with dynamical symmetry based on group S{sub p}(6,R) for the description of collective modes of atomic nuclei, analysis of the Goldstone bosons in nuclear matter and analysis of saturation properties of nuclear matter. Research in theoretical astrophysics is mainly devoted to the analysis of magnetic properties of hadronic matter in neutron stars with proton admixture. Studies in general physics concern problem related to the Galilean covariance of classical and quantum mechanics. The detailed results obtained in various fields are summarised in presented abstracts as well as information about employed personnel, publications, contribution to conferences, reports, workshops and seminars.

  3. Overview. Department of Theoretical Physics. Section 4

    Energy Technology Data Exchange (ETDEWEB)

    Kwiecinski, J [Institute of Nuclear Physics, Cracow (Poland)

    1996-12-31

    Research activity of the Department of the Theoretical Physics spans a wide variety of problems in theoretical high-energy and elementary particle physics, theoretical nuclear physics, theory of the nuclear matter, quark gluon plasma and relativistic heavy-ion collisions, theoretical astrophysics, as well as general physics. Theoretical research in high energy and elementary particle physics is concentrated on the theory of deep inelastic lepton scattering in the region of low x and its phenomenological implication for the ep collider HERA at DESY, on the theory of nonleptonic decays of hadrons, and on low energy {pi}{pi} and K-anti-K interactions and scalar meson spectroscopy. The activity in the theory of relativistic heavy-ion collisions is focused on the study of quark condensate fluctuations, on the analysis of critical scattering near the chiral phase transition, and on Bose-Einstein correlation in heavy-ion collisions. Theoretical studies in nuclear physics and in theory of nuclear matter concern analysis of models, with dynamical symmetry based on group S{sub p}(6,R) for the description of collective modes of atomic nuclei, analysis of the Goldstone bosons in nuclear matter and analysis of saturation properties of nuclear matter. Research in theoretical astrophysics is mainly devoted to the analysis of magnetic properties of hadronic matter in neutron stars with proton admixture. Studies in general physics concern problem related to the Galilean covariance of classical and quantum mechanics. The detailed results obtained in various fields are summarised in presented abstracts as well as information about employed personnel, publications, contribution to conferences, reports, workshops and seminars.

  4. Overview. Department of Theoretical Physics. Section 4

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    1995-01-01

    Research activity of the Department of the Theoretical Physics spans a wide variety of problems in theoretical high-energy and elementary particle physics, theoretical nuclear physics, theory of the nuclear matter, quark gluon plasma and relativistic heavy-ion collisions, theoretical astrophysics, as well as general physics. Theoretical research in high energy and elementary particle physics is concentrated on the theory of deep inelastic lepton scattering in the region of low x and its phenomenological implication for the ep collider HERA at DESY, on the theory of nonleptonic decays of hadrons, and on low energy ππ and K-anti-K interactions and scalar meson spectroscopy. The activity in the theory of relativistic heavy-ion collisions is focused on the study of quark condensate fluctuations, on the analysis of critical scattering near the chiral phase transition, and on Bose-Einstein correlation in heavy-ion collisions. Theoretical studies in nuclear physics and in theory of nuclear matter concern analysis of models, with dynamical symmetry based on group S p (6,R) for the description of collective modes of atomic nuclei, analysis of the Goldstone bosons in nuclear matter and analysis of saturation properties of nuclear matter. Research in theoretical astrophysics is mainly devoted to the analysis of magnetic properties of hadronic matter in neutron stars with proton admixture. Studies in general physics concern problem related to the Galilean covariance of classical and quantum mechanics. The detailed results obtained in various fields are summarised in presented abstracts as well as information about employed personnel, publications, contribution to conferences, reports, workshops and seminars

  5. Corruption and Economic Development in Nigeria: A Theoretical ...

    African Journals Online (AJOL)

    Corruption and Economic Development in Nigeria: A Theoretical Review. ... By using a theoretical method of analysis, the study reveals that corruption has been a deterrent to economic development in Nigeria. ... Section two discusses the theoretical and conceptual issues in corruption and economic development. Section ...

  6. Thermodynamic analysis and theoretical study of a continuous operation solar-powered adsorption refrigeration system

    International Nuclear Information System (INIS)

    Hassan, H.Z.; Mohamad, A.A.

    2013-01-01

    Due to the intermittent nature of the solar radiation, the day-long continuous production of cold is a challenge for solar-driven adsorption cooling systems. In the present study, a developed solar-powered adsorption cooling system is introduced. The proposed system is able to produce cold continuously along the 24-h of the day. The theoretical thermodynamic operating cycle of the system is based on adsorption at constant temperature. Both the cooling system operating procedure as well as the theoretical thermodynamic cycle are described and explained. Moreover, a steady state differential thermodynamic analysis is performed for all components and processes of the introduced system. The analysis is based on the energy conservation principle and the equilibrium dynamics of the adsorption and desorption processes. The Dubinin–Astakhov adsorption equilibrium equation is used in this analysis. Furthermore, the thermodynamic properties of the refrigerant are calculated from its equation of state. The case studied represents a water chiller which uses activated carbon–methanol as the working pair. The chiller is found to produce a daily mass of 2.63 kg cold water at 0 °C from water at 25 °C per kg of adsorbent. Moreover, the proposed system attains a cooling coefficient of performance of 0.66. - Highlights: • A new continuous operation solar-driven adsorption refrigeration system is introduced. • The theoretical thermodynamic cycle is presented and explained. • A complete thermodynamic analysis is performed for all components and processes of the system. • Activated carbon–methanol is used as the working pair in the case study

  7. A Theoretical Study of Microwave Beam Absorption by a Rectenna

    Science.gov (United States)

    Ott, J. H.; Rice, J. S.; Thorn, D. C.

    1981-01-01

    The theoretical operational parameters for the workable satellite power system were examined. The system requirements for efficient transmission and reception of an environmentally benign microwave beam were determined.

  8. Studies in theoretical particle physics

    International Nuclear Information System (INIS)

    Kaplan, D.B.

    1991-01-01

    This proposal focuses on research on three distinct areas of particle physics: (1) Nonperturbative QCD. I tend to continue work on analytic modelling of nonperturbative effects in the strong interactions. I have been investigating the theoretical connection between the nonrelativistic quark model and QCD. The primary motivation has been to understand the experimental observation of nonzero matrix elements involving current strange quarks in ordinary matter -- which in the quark model has no strange quark component. This has led to my present work on understanding constituent (quark model) quarks as collective excitations of QCD degrees of freedom. (2) Weak Scale Baryogenesis. A continuation of work on baryogenesis in the early universe from weak interactions. In particular, an investigation of baryogenesis occurring during the weak phase transition through anomalous baryon violating processes in the standard model of weak interactions. (3) Flavor and Compositeness. Further investigation of a new mechanism that I recently discovered for dynamical mass generation for fermions, which naturally leads to a family hierarchy structure. A discussion of recent past work is found in the next section, followed by an outline of the proposed research. A recent publication from each of these three areas is attached to this proposal

  9. Cyclotron tubes - a theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Mourier, G

    1980-12-01

    The introduction presents a general discussion of electron cyclotron masers (ECM): resonance, relativistic effects, elementary quantum aspects, the classical relativistic bunching and the optimum value of the electric field. The practical structure - in particular that of the gyrotron - is specified only insofar as it is useful for understanding the following chapters. The main parameters are discussed. Section 2 develops a nonlinear adiabatic or orbital theory of electron motion which alleviates calculations considerably while keeping numerical errors low enough for many practical cases. Its results are compared to a rigorous integration in one case. Other cases show the importance of the electric field profile inside the resonant cavity. Section 3 is devoted to space charge phenomena, and, for the most part, to a linear theory with space charge. In its limited range of validity (low-energy electrons), the theory indicates a strong impact of space charge for low a.c. fields and exhibits a pure beam instability. Section 4 is devoted to circuit equations with emphasis on the special features of cavities consisting of a long waveguide near cutoff. The conclusion indicates some trends of gyrotron development and corresponding theoretical problems.

  10. [Habermas and Paulo Freire: theoretical referrals for the study on communication in nursing].

    Science.gov (United States)

    Larocca, Liliana Muller; Mazza, Verônica de Azevedo

    2003-08-01

    The present work has the objective of introducing the ideas of Jürgen Habermas and Paulo Freire about the dialogue as a fundamental human phenomenon, data on their trajectories of life, ideological approaches when locating the human being through history and their relevance as theoretical referrals for the study on communication in the process of the nurse's work.

  11. Theoretical study on the photoionization of metanal and fluoromethane

    International Nuclear Information System (INIS)

    Tanaka, Helder Kenji; Silveira, Tiago Rodrigues; Nascimento, Edmar Moraes do

    2011-01-01

    Full text. The photoionization study of biological interest molecules has increased last few years due to the basic interest in the fundamental nature of electronic structures and scattering molecular processes. It was considered to this study hypothesis in that simple molecules would give birth to more complex molecules through photochemical reactions induced by interstellar radiation. This paper shows a theoretical study over photoionization of the valence shells of some biological interest molecules. Cross sections and parameters of asymmetry are set due to ab initio, using the continued fractions method to determine the scattering matrix and wave functions of the continuum. Results will be presented to the valence shell photoionization of formaldehyde (CH 2 O) and fluoromethane (CH 3 F). This work is part of a larger project to study of biological interest molecules, motivated by the hypothesis that based on these simple molecules, physicochemical processes may have given origin to more complex molecules responsible for the production of terrestrial life. The formamide, for example, has been subject of interest between researchers as a possible material from which can be created RNA bases. In this case has been studied the production of guanine from the formamide heated while irradiated by ultraviolet radiation

  12. A theoretical study on the influence of gas adsorption on interparticle forces in powders

    NARCIS (Netherlands)

    Cottaar, E.J.E.; Rietema, K.

    1986-01-01

    Using data from the literature and some additional experiments it is investigated whether the interparticle forces in general and more specifically the cohesion between particles are influenced by the physisorption of gases. In this otherwise theoretical study the force to be applied to a particle

  13. Theoretical and experimental study of microstrip-to-slot line uniplanar transition

    Science.gov (United States)

    Yook, Jong-Gwan; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Taub, Susan R.

    1994-05-01

    Recent advances in MMCI technology make it possible to construct transitions from CPW-to-microstrip with via hole, microstrip-to-slot line and microshield line-to-CPW all of which have potential applications in the feed network of antennas. In this study we investigate the characteristics of the microstrip-to-slot line uniplanar transition using the finite element methods (FEM) and finite difference time domain (FDTD) techniques, and compared the theoretical results with the measurements. In both cases, the results agree with the measurements within a few percent.

  14. Game theoretic approaches for spectrum redistribution

    CERN Document Server

    Wu, Fan

    2014-01-01

    This brief examines issues of spectrum allocation for the limited resources of radio spectrum. It uses a game-theoretic perspective, in which the nodes in the wireless network are rational and always pursue their own objectives. It provides a systematic study of the approaches that can guarantee the system's convergence at an equilibrium state, in which the system performance is optimal or sub-optimal. The author provides a short tutorial on game theory, explains game-theoretic channel allocation in clique and in multi-hop wireless networks and explores challenges in designing game-theoretic m

  15. Experimental, theoretical, and numerical studies of small scale combustion

    Science.gov (United States)

    Xu, Bo

    Recently, the demand increased for the development of microdevices such as microsatellites, microaerial vehicles, micro reactors, and micro power generators. To meet those demands the biggest challenge is obtaining stable and complete combustion at relatively small scale. To gain a fundamental understanding of small scale combustion in this thesis, thermal and kinetic coupling between the gas phase and the structure at meso and micro scales were theoretically, experimentally, and numerically studied; new stabilization and instability phenomena were identified; and new theories for the dynamic mechanisms of small scale combustion were developed. The reduction of thermal inertia at small scale significantly reduces the response time of the wall and leads to a strong flame-wall coupling and extension of burning limits. Mesoscale flame propagation and extinction in small quartz tubes were theoretically, experimentally and numerically studied. It was found that wall-flame interaction in mesoscale combustion led to two different flame regimes, a heat-loss dominant fast flame regime and a wall-flame coupling slow flame regime. The nonlinear transition between the two flame regimes was strongly dependent on the channel width and flow velocity. It is concluded that the existence of multiple flame regimes is an inherent phenomenon in mesoscale combustion. In addition, all practical combustors have variable channel width in the direction of flame propagation. Quasi-steady and unsteady propagations of methane and propane-air premixed flames in a mesoscale divergent channel were investigated experimentally and theoretically. The emphasis was the impact of variable cross-section area and the flame-wall coupling on the flame transition between different regimes and the onset of flame instability. For the first time, spinning flames were experimentally observed for both lean and rich methane and propane-air mixtures in a broad range of equivalence ratios. An effective Lewis number

  16. Curriculum, Curriculum Development, Curriculum Studies? Problematising Theoretical Ambiguities in Doctoral Theses in the Education Field

    Science.gov (United States)

    du Preez, Petro; Simmonds, Shan

    2014-01-01

    Theoretical ambiguities in curriculum studies result in conceptual mayhem. Accordingly, they hinder the development of the complicated conversation on curriculum as a verb. This article aims to contribute to reconceptualizing curriculum studies as a dynamic social practice that aspires to thinking and acting with intelligences and sensitivity so…

  17. Theoretical XANES Study of the Activated Nickel (t-Amylisocyanide) Molecule

    International Nuclear Information System (INIS)

    Glover, J. L.; Chantler, C. T.; Soldatov, A. V.; Smolentsev, G.; Feiters, M. C.

    2007-01-01

    XANES is one of the most powerful techniques for investigating the active centres of non-crystalline systems such as synthetic catalysts and enzymes. We have investigated XANES for an active species in the Ni-catalyzed polymerization of isocyanides, the activated Ni (t-amylisocyanide) complex, using two of the most popular theoretical approaches. This is a very large cluster for which it is extremely difficult to derive a converged solution using the Finite Difference Method. The cluster has been linked to important chemical developments for catalysts for isocyanide polymerization. Predicted XANES for the nano-cluster are compared with experimental data, providing an important test for different theoretical approaches. Developments of a finite element method gave excellent agreement with the experimental data, while simpler models were relatively unsuccessful

  18. Theoretical studies of binaries in astrophysics

    Science.gov (United States)

    Dischler, Johann Sebastian

    This thesis introduces and summarizes four papers dealing with computer simulations of astrophysical processes involving binaries. The first part gives the rational and theoretical background to these papers. In paper I and II a statistical approach to studying eclipsing binaries is described. By using population synthesis models for binaries the probabilities for eclipses are calculated for different luminosity classes of binaries. These are compared with Hipparcos data and they agree well if one uses a standard input distribution for the orbit sizes. If one uses a random pairing model, where both companions are independently picked from an IMF, one finds too feclipsing binaries by an order of magnitude. In paper III we investigate a possible scenario for the origin of the stars observed close to the centre of our galaxy, called S stars. We propose that a cluster falls radially cowards the central black hole. The binaries within the cluster can then, if they have small impact parameters, be broken up by the black hole's tidal held and one of the components of the binary will be captured by the black hole. Paper IV investigates how the onset of mass transfer in eccentric binaries depends on the eccentricity. To do this we have developed a new two-phase SPH scheme where very light particles are at tire outer edge of our simulated star. This enables us to get a much better resolution of the very small mass that is transferred in close binaries. Our simulations show that the minimum required distance between the stars to have mass transfer decreases with the eccentricity.

  19. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study

    Science.gov (United States)

    Phillips, Cameron J; Marshall, Andrea P; Chaves, Nadia J; Jankelowitz, Stacey K; Lin, Ivan B; Loy, Clement T; Rees, Gwyneth; Sakzewski, Leanne; Thomas, Susie; To, The-Phung; Wilkinson, Shelley A; Michie, Susan

    2015-01-01

    Background The Theoretical Domains Framework (TDF) is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. Purpose This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Methods Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Results Three main themes and associated subthemes were identified including: 1) reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings); 2) challenges using the TDF (time and resources, operationalization of the TDF) and; 3) future use of the TDF. Conclusion The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF. PMID:25834455

  20. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study.

    Science.gov (United States)

    Phillips, Cameron J; Marshall, Andrea P; Chaves, Nadia J; Jankelowitz, Stacey K; Lin, Ivan B; Loy, Clement T; Rees, Gwyneth; Sakzewski, Leanne; Thomas, Susie; To, The-Phung; Wilkinson, Shelley A; Michie, Susan

    2015-01-01

    The Theoretical Domains Framework (TDF) is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Three main themes and associated subthemes were identified including: 1) reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings); 2) challenges using the TDF (time and resources, operationalization of the TDF) and; 3) future use of the TDF. The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF.

  1. The theoretical study of the optical klystron free electron laser

    International Nuclear Information System (INIS)

    Yang Zhenhua

    2001-01-01

    The work of the theoretical study and numerical simulation of optical klystron free electron laser is supported by National 863 Research Development Program and National Science Foundation of China. The object of studying UV band free electron laser (FEL) is to understand the physical law of optical klystron FEL and to gain experience for design. A three-dimensional code OPFEL are made and it is approved that the code is correct completely. The magnetic field of the optical klystron, the energy modulation of the electron beam, the density modulation of the electron beam, spontaneous emission of the electron beam in optical klystron, the harmonic super-radiation of the electron beam, and the effects of the undulator magnetic field error on modulation of the electron beam energy are simulated. These results are useful for the future experiments

  2. Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes

    International Nuclear Information System (INIS)

    Cortez, Luis; Berrios, Cristhian; Yanez, Mauricio; Cardenas-Jiron, Gloria I.

    2009-01-01

    A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.

  3. Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cortez, Luis [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Berrios, Cristhian [Laboratorio de Electrocatalisis, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Yanez, Mauricio [Laboratorio de Recursos Renovables, Centro de Biotecnologia, Universidad de Concepcion, Casilla-160 C, Concepcion (Chile); Cardenas-Jiron, Gloria I., E-mail: gloria.cardenas@usach.cl [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile)

    2009-11-26

    A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.

  4. Theoretical study of diaquamalonatozinc(II) single crystal for applications in non-linear optical devices

    Science.gov (United States)

    Chakraborty, Mitesh; Rai, Vineet Kumar

    2017-12-01

    The aim of the present paper is to employ theoretical methods to investigate the zero field splitting (ZFS) parameter and to investigate the position of the dopant in the host. These theoretical calculations have been compared with the empirical results. The superposition model (SPM) with the microscopic spin-Hamiltonian (MSH) theory and the coefficient of fractional parentage have been employed to investigate the dopant manganese(II) ion substitution in the diaquamalonatozinc(II) (DAMZ) single crystal. The magnetic parameters, viz. g-tensor and D-tensor, has been determined by using the ORCA program package developed by F Neese et al. The unrestricted Kohn-Sham orbitals-based Pederson-Khanna (PK) as the unperturbed wave function is observed to be the most suitable for the computational calculation of spin-orbit tensor (D^{SO}) of the axial ZFS parameter D. The effects of spin-spin dipolar couplings are taken into account. The unrestricted natural orbital (UNO) is used for the calculation of spin-spin dipolar contributions to the ZFS tensor. A comparative study of the quantum mechanical treatment of Pederson-Khanna (PK) with coupled perturbation (CP) is reported in the present study. The unrestricted Kohn-Sham-based natural orbital with Pederson-Khanna-type of perturbation approach validates the experimental results in the evaluation of ZFS parameters. The theoretical results are appropriate with the experimental ones and indicate the interstitial occupancy of Mn^{2+} ion in the host matrix.

  5. Theoretical and Experimental Study of Plasmonic Polymer Solar Cells

    DEFF Research Database (Denmark)

    Mirsafaei, Mina; Adam, Jost; Madsen, Morten

    The organic bulk hetero-junction solar cell has remarkable advantages such as low cost, mechanical flexibility and simple process techniques. Recently, low-band gap photoactive materials have obtained a significant attention due to their potential to absorb a wider range of the solar spectrum...... to attain higher power conversion efficiencies. Many low-band gap photoactive materials, however, still show a relatively low external quantum efficiency of less than 60% [1]. One possible approach to improve the device performance is to increase the light absorption in the active layer. This may, amongst...... other approaches, be achieved by using nano- or micro-structures that trap light at specific wavelengths [2], or by using the localized surface plasmon resonance effect of metal nanoparticles in the devices. In this work, we theoretically studied planar polymer solar cell based on finite-difference time...

  6. Experimental and theoretical studies of buoyant-thermo capillary flow

    International Nuclear Information System (INIS)

    Favre, E.; Blumenfeld, L.; Soubbaramayer

    1996-01-01

    In the AVLIS process, uranium metal is evaporated using a high power electron gun. We have prior discussed the power balance equation in the electron beam evaporation process and pointed out, among the loss terms, the importance of the power loss due to the convective flow in the molten pool driven by buoyancy and thermo capillarity. An empirical formula has been derived from model experiments with cerium, to estimate the latter power loss and that formula can be used practically in engineering calculations. In order to complete the empirical approach, a more fundamental research program of theoretical and experimental studies have been carried out in Cea-France, with the objective of understanding the basic phenomena (heat transport, flow instabilities, turbulence, etc.) occurring in a convective flow in a liquid layer locally heated on its free surface

  7. Opioid Prescribing After Curative-Intent Surgery: A Qualitative Study Using the Theoretical Domains Framework.

    Science.gov (United States)

    Lee, Jay S; Parashar, Vartika; Miller, Jacquelyn B; Bremmer, Samantha M; Vu, Joceline V; Waljee, Jennifer F; Dossett, Lesly A

    2018-07-01

    Excessive opioid prescribing is common after curative-intent surgery, but little is known about what factors influence prescribing behaviors among surgeons. To identify targets for intervention, we performed a qualitative study of opioid prescribing after curative-intent surgery using the Theoretical Domains Framework, a well-established implementation science method for identifying factors influencing healthcare provider behavior. Prior to data collection, we constructed a semi-structured interview guide to explore decision making for opioid prescribing. We then conducted interviews with surgical oncology providers at a single comprehensive cancer center. Interviews were recorded, transcribed verbatim, then independently coded by two investigators using the Theoretical Domains Framework to identify theoretical domains relevant to opioid prescribing. Relevant domains were then linked to behavior models to select targeted interventions likely to improve opioid prescribing. Twenty-one subjects were interviewed from November 2016 to May 2017, including attending surgeons, resident surgeons, physician assistants, and nurses. Five theoretical domains emerged as relevant to opioid prescribing: environmental context and resources; social influences; beliefs about consequences; social/professional role and identity; and goals. Using these domains, three interventions were identified as likely to change opioid prescribing behavior: (1) enablement (deploy nurses during preoperative visits to counsel patients on opioid use); (2) environmental restructuring (provide on-screen prompts with normative data on the quantity of opioid prescribed); and (3) education (provide prescribing guidelines). Key determinants of opioid prescribing behavior after curative-intent surgery include environmental and social factors. Interventions targeting these factors are likely to improve opioid prescribing in surgical oncology.

  8. Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Wesley D. [University of Georgia, Department of Chemistry and Center for Computational Quantum Chemistry; Schaefer, Henry F. [University of Georgia, Center for Computational Quantum Chemistry

    2018-04-08

    The research program supported by this DOE grant carried out both methodological development and computational applications of first-principles theoretical chemistry based on quantum mechanical wavefunctions, as directed toward understanding and harnessing the fundamental chemical physics of combustion. To build and refine the world’s database of thermochemistry, spectroscopy, and chemical kinetics, predictive and definitive computational methods are needed that push the envelope of modern electronic structure theory. The application of such methods has been made to gain comprehensive knowledge of the paradigmatic reaction networks by which the n- and i-propyl, t-butyl, and n-butyl radicals are oxidized by O2. Numerous ROO and QOOH intermediates in these R + O2 reaction systems have been characterized along with the interconnecting isomerization transition states and the barriers leading to fragmentation. Other combustion-related intermediates have also been studied, including methylsulfinyl radical, cyclobutylidene, and radicals derived from acetaldehyde and vinyl alcohol. Theoretical advances have been achieved and made available to the scientific community by implementation into PSI4, an open-source electronic structure computer package emphasizing automation, advanced libraries, and interoperability. We have pursued the development of universal explicitly correlated methods applicable to general electronic wavefunctions, as well as a framework that allows multideterminant reference functions to be expressed as a single determinant from quasiparticle operators. Finally, a rigorous analytical tool for correlated wavefunctions has been created to elucidate dispersion interactions, which play essential roles in many areas of chemistry, but whose effects are often masked and enigmatic. Our research decomposes and analyzes the coupled-cluster electron correlation energy in molecular systems as a function of interelectronic distance. Concepts

  9. Theoretical Studies of TE-Wave Propagation as a Diagnostic for Electron Cloud

    International Nuclear Information System (INIS)

    Penn, Gregory E.; Vay, Jean-Luc

    2010-01-01

    The propagation of TE waves is sensitive to the presence of an electron cloud primarily through phase shifts generated by the altered dielectric function, but can also lead to polarization changes and other effects, especially in the presence of magnetic fields. These effects are studied theoretically and also through simulations using WARP. Examples are shown related to CesrTA parameters, and used to observe different regimes of operation as well as to validate estimates of the phase shift.

  10. Theoretical study of some aspects of the nucleo-bases reactivity: definition of new theoretical tools for the study of chemical reactivity

    International Nuclear Information System (INIS)

    Labet, V.

    2009-09-01

    In this work, three kinds of nucleo-base damages were studied from a theoretical point of view with quantum chemistry methods based on the density-functional theory: the spontaneous deamination of cytosine and its derivatives, the formation of tandem lesion induced by hydroxyl radicals in anaerobic medium and the formation of pyrimidic dimers under exposition to an UV radiation. The complementary use of quantitative static methods allowing the exploration of the potential energy surface of a chemical reaction, and of 'conceptual DFT' principles, leads to information concerning the mechanisms involved and to the rationalization of the differences in the nucleo-bases reactivity towards the formation of a same kind of damage. At the same time, a reflexion was undertaken on the asynchronous concerted mechanism concept, in terms of physical meaning of the transition state, respect of the Maximum Hardness Principle, and determination of the number of primitive processes involved. Finally, a new local reactivity index was developed, relevant to understand the reactivity of a molecular system in an excited state. (author)

  11. Photoelectron Angular Distributions of Transition Metal Dioxide Anions - a joint experimental and theoretical study

    Science.gov (United States)

    Iordanov, Ivan; Gunaratne, Dasitha; Harmon, Christopher; Sofo, Jorge; Castleman, A. W., Jr.

    2012-02-01

    Angular-resolved photoelectron spectroscopy (PES) studies of the MO2- (M=Ti, Zr, Hf, Co, Rh) clusters are presented for the first time along with theoretical calculations of their properties. We confirm previously reported non-angular PES results for the vertical detachment energies (VDE), vibrational energies and geometric structures of these clusters and further explore the effect of the 'lanthanide contraction' on the MO2- clusters by comparing the electronic spectra of 4d and 5d transition metal dioxides. Angular-resolved PES provides the angular momentum contributions to the HOMO of these clusters and we use theoretical calculations to examine the HOMO and compare to our experimental results. First-principles calculations are done using both density functional theory (DFT) and the coupled-cluster, singles, doubles and triples (CCSD(T)) methods.

  12. Theoretical study of liquid droplet dispersion in a venturi scrubber.

    Science.gov (United States)

    Fathikalajahi, J; Talaie, M R; Taheri, M

    1995-03-01

    The droplet concentration distribution in an atomizing scrubber was calculated based on droplet eddy diffusion by a three-dimensional dispersion model. This model is also capable of predicting the liquid flowing on the wall. The theoretical distribution of droplet concentration agrees well with experimental data given by Viswanathan et al. for droplet concentration distribution in a venturi-type scrubber. The results obtained by the model show a non-uniform distribution of drops over the cross section of the scrubber, as noted by the experimental data. While the maximum of droplet concentration distribution may depend on many operating parameters of the scrubber, the results of this study show that the highest uniformity of drop distribution will be reached when penetration length is approximately equal to one-fourth of the depth of the scrubber. The results of this study can be applied to evaluate the removal efficiency of a venturi scrubber.

  13. Assessing a Theoretical Model on EFL College Students

    Science.gov (United States)

    Chang, Yu-Ping

    2011-01-01

    This study aimed to (1) integrate relevant language learning models and theories, (2) construct a theoretical model of college students' English learning performance, and (3) assess the model fit between empirically observed data and the theoretical model proposed by the researchers of this study. Subjects of this study were 1,129 Taiwanese EFL…

  14. Theoretical studies of turbulence and anomalous transport in toroidal confinement devices

    International Nuclear Information System (INIS)

    Terry, P.W.

    1990-01-01

    The research performed under this grant during the current year has focused on key issues with respect to turbulence and transport in toroidal confinement devices. This work includes theoretical and computational studies of electron thermal confinement which have concentrated on the role of sheared poloidal flow in suppressing turbulence and transport, trapped ion convective cell turbulence and microtearing turbulence; analytical studies of anomalous particle transport and pinch mechanisms, and comparison with experimental measurement; development of the theory of self-consistent radial transport of field-aligned momentum in the tokamak and RFP; and work on other topics (ion temperature gradient driven turbulence, RFP fluctuation theory, coherent structures). Progress and publications in these areas are briefly summarized in this report. 20 refs

  15. Activity systems modeling as a theoretical lens for social exchange studies

    Directory of Open Access Journals (Sweden)

    Ernest Jones

    2016-01-01

    Full Text Available The social exchange perspective seeks to acknowledge, understand and predict the dynamics of social interactions. Empirical research involving social exchange constructs have grown to be highly technical including confirmatory factor analysis to assess construct distinctiveness and structural equation modeling to assess construct causality. Each study seemingly strives to assess how underlying social exchange theoretic constructs interrelate. Yet despite this methodological depth and resultant explanatory and predictive power, a significant number of studies report findings that, once synthesized, suggest an underlying persistent threat of conceptual or construct validity brought about by a search for epistemological parsimony. Further, it is argued that a methodological approach that embraces inherent complexity such as activity systems modeling facilitates the search for simplified models while not ignoring contextual factors.

  16. Theoretical aspects of studies of oxide and semiconductor surfaces using low energy positrons

    Science.gov (United States)

    Fazleev, N. G.; Maddox, W. B.; Weiss, A. H.

    2011-01-01

    This paper presents the results of a theoretical study of positron surface and bulk states and annihilation characteristics of surface trapped positrons at the oxidized Cu(100) single crystal and at both As- and Ga-rich reconstructed GaAs(100) surfaces. The variations in atomic structure and chemical composition of the topmost layers of the surfaces associated with oxidation and reconstructions and the charge redistribution at the surfaces are found to affect localization and spatial extent of the positron surface-state wave functions. The computed positron binding energy, work function, and annihilation characteristics reveal their sensitivity to charge transfer effects, atomic structure and chemical composition of the topmost layers of the surfaces. Theoretical positron annihilation probabilities with relevant core electrons computed for the oxidized Cu(100) surface and the As- and Ga-rich reconstructed GaAs(100) surfaces are compared with experimental ones estimated from the positron annihilation induced Auger peak intensities measured from these surfaces.

  17. Theoretical and experimental study of Chen chaotic system with notch filter feedback control

    International Nuclear Information System (INIS)

    Ming, Zhang Xiao; Jian-Hua, Peng; Ju-Fang, Chen

    2010-01-01

    Since the past two decades, the time delay feedback control method has attracted more and more attention in chaos control studies because of its simplicity and efficiency compared with other chaos control schemes. Recently, it has been proposed to suppress low-dimensional chaos with the notch filter feedback control method, which can be implemented in a laser system. In this work, we have analytically determined the controllable conditions for notch filter feedback controlling of Chen chaotic system in terms of the Hopf bifurcation theory. The conditions for notch filter feedback controlled Chen chaoitc system having a stable limit cycle solution are given. Meanwhile, we also analysed the Hopf bifurcation direction, which is very important for parameter settings in notch filter feedback control applications. Finally, we apply the notch filter feedback control methods to the electronic circuit experiments and numerical simulations based on the theoretical analysis. The controlling results of notch filter feedback control method well prove the feasibility and reliability of the theoretical analysis. (general)

  18. Single-phase and two phase bubbly flow in a T connection: theoretical and experimental study

    International Nuclear Information System (INIS)

    Hervieu, Eric

    1988-01-01

    The objective of this research thesis is to highlight the driving factors of the separation of phases of a bubbly flow in a T junction, and to develop a prediction model. In a first part, the author reports the rigorous formulation of equations averaged on the T volume. He shows that it's not possible to solve globally the problem with these equations. Then, he reports a bibliographical study on the modelling of a bubbly flow, and, based upon this study, highlights intrinsic characteristics of the flow, and explains its dynamic mechanisms. He reports the development of the theoretical model, and describes the experimental installation used to validate it. In the third part, he reports the study of the liquid-gas interaction, and presents the adopted approach: study of the behaviour of an isolated bubble within a single-phase flow. Experimentation is used to check theoretical predictions. Results are used to compute phase separation. The obtained results are again compared with experimental results to validate the global relevance of the model [fr

  19. Mechanical properties of jennite: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.

  20. Theoretical studies in nuclear reaction and nuclear structure. Final report, January 1, 1975--June 30, 1976

    International Nuclear Information System (INIS)

    Banerjee, M.K.; Griffin, J.J.

    1977-07-01

    Progress in theoretical research is reported under the following readings: (1) few nuclear reactions, Eikonal approximations, and optical models; (2) pion reactions; (3) nuclear structure by reaction studies; (4) nuclear dynamics

  1. Theoretical study on flow-induced vibration of a cylindrical weir due to fluid discharge

    International Nuclear Information System (INIS)

    Fujita, Katsuhisa; Ito, Tomohiro; Hirota, Kazuo; Kodama, Tetsuhiko

    1994-01-01

    In a FBR, the inside of the reactor vessel is cooled by liquid sodium. Liquid sodium is supplied to the upper plenum from its bottom and discharges over the top of the cylindrical weir down to the lower plenum. The weir is so thin in order to decrease the thermal stress on it that the fluid--structure interaction becomes predominant. A fluidelastic vibration of the weir due to fluid discharge was discovered in a French FBR. In this study, a theoretical model was developed on the ''fluid--elastic mode'' instability of a cylindrical weir due to fluid discharge from the upper plenum to the lower plenum. In the analysis, the fluctuation of both the discharge flow rate over a weir due to the vibration of the cylindrical shell and the pressure in the lower plenum due to fluid discharge were formulated. Instability criteria was derived from the added damping ratio due to fluid discharge using modal analysis. The natural modes and modal mass of the weir were obtained by the analysis using the FEM code taking the fluid - structure interaction into consideration. The theoretical instability range in terms of the fall height and the flow rate is compared with the experimental results. The theoretical values showed a good agreement with the experimental ones

  2. THEORETICAL AND METHODOLOGICAL APPROACHES TO THE STUDY OF PROTEST ACTIVITY IN THE WESTERN SOCIOLOGICAL THOUGHT

    OpenAIRE

    Купрєєва, Ю. О.

    2015-01-01

    In this article the author discusses the main theoretical and methodological approaches to the study of protest activity. Among them - the theory of collective behavior, the relative deprivation theory, the new social movements theory and the resource mobilization theory. Highlighted their strengths and weaknesses. Focused on the new direction of protest studies connected with the development of the Internet.

  3. Electronic structure of copper phthalocyanine : An experimental and theoretical study of occupied and unoccupied levels

    NARCIS (Netherlands)

    Evangelista, Fabrizio; Carravetta, Vincenzo; Stefani, Giovanni; Jansik, Branislav; Alagia, Michele; Stranges, Stefano; Ruocco, Alessandro

    2007-01-01

    An experimental and theoretical study of the electronic structure of copper phthalocyanine (CuPc) molecule is presented. We performed x-ray photoemission spectroscopy (XPS) and photoabsorption [x-ray absorption near-edge structure (XANES)] gas phase experiments and we compared the results with

  4. Theoretical study and experimental investigation of mixed and natural circulation in LMFBR core subassemblies

    International Nuclear Information System (INIS)

    Leteinturier, D.; Blanc, D.; Menant, B.; Basque, G.

    1980-02-01

    A presentation is made of theoretical and experimental studies carried out in France on mixed and natural convection in LMFBR wire wrapped bundles. Two codes are described, one for mixed convection THERNAT and the other for natural convection BACCHUS. THe related experimental program FETUNA, with electrically heated bundles in sodium loops, is also presented

  5. Theoretical Study of Penalized-Likelihood Image Reconstruction for Region of Interest Quantification

    International Nuclear Information System (INIS)

    Qi, Jinyi; Huesman, Ronald H.

    2006-01-01

    Region of interest (ROI) quantification is an important task in emission tomography (e.g., positron emission tomography and single photon emission computed tomography). It is essential for exploring clinical factors such as tumor activity, growth rate, and the efficacy of therapeutic interventions. Statistical image reconstruction methods based on the penalized maximum-likelihood (PML) or maximum a posteriori principle have been developed for emission tomography to deal with the low signal-to-noise ratio of the emission data. Similar to the filter cut-off frequency in the filtered backprojection method, the regularization parameter in PML reconstruction controls the resolution and noise tradeoff and, hence, affects ROI quantification. In this paper, we theoretically analyze the performance of ROI quantification in PML reconstructions. Building on previous work, we derive simplified theoretical expressions for the bias, variance, and ensemble mean-squared-error (EMSE) of the estimated total activity in an ROI that is surrounded by a uniform background. When the mean and covariance matrix of the activity inside the ROI are known, the theoretical expressions are readily computable and allow for fast evaluation of image quality for ROI quantification with different regularization parameters. The optimum regularization parameter can then be selected to minimize the EMSE. Computer simulations are conducted for small ROIs with variable uniform uptake. The results show that the theoretical predictions match the Monte Carlo results reasonably well

  6. Theoretical study of the aluminum melting curve to very high pressure

    International Nuclear Information System (INIS)

    Moriarty, J.A.; Young, D.A.; Ross, M.

    1984-01-01

    A detailed theoretical study of the Al melting curve from normal melting conditions to pressures in the vicinity of 2 Mbar is presented. The analysis is based on two parallel, but distinct, treatments of the metal: the first from rigorous generalized pseudopotential theory involving first-principles nonlocal pseudopotentials and the second from a parametrized local pseudopotential model which has been accurately fit to first-principles band-theory and experimental equation-of-state data. Both treatments utilize full lattice-dynamical calculations of the phonon free energy in the solid, within the harmonic approximation, and fluid variational theory to obtain the free energy of the liquid. Particular attention is focused on the choice of the reference system in implementing the fluid variational theory. It is shown that in Al the soft-sphere model of Ross produces a lower (and hence more accurate) liquid free energy than either the hard-sphere or one-component-plasma reference systems, and is, moreover, necessary to obtain a reasonable quantitative description of the melting properties. With the soft-sphere system, the two theoretical treatments give results in good overall agreement with each other and with experiment. In particular, melting on the shock Hugoniot is predicted to begin at about 1.2 Mbar and to end at about 1.55 Mbar, in excellent agreement with the recent preliminary measurements of McQueen

  7. Demystifying Theoretical Sampling in Grounded Theory Research

    Directory of Open Access Journals (Sweden)

    Jenna Breckenridge BSc(Hons,Ph.D.Candidate

    2009-06-01

    Full Text Available Theoretical sampling is a central tenet of classic grounded theory and is essential to the development and refinement of a theory that is ‘grounded’ in data. While many authors appear to share concurrent definitions of theoretical sampling, the ways in which the process is actually executed remain largely elusive and inconsistent. As such, employing and describing the theoretical sampling process can present a particular challenge to novice researchers embarking upon their first grounded theory study. This article has been written in response to the challenges faced by the first author whilst writing a grounded theory proposal. It is intended to clarify theoretical sampling for new grounded theory researchers, offering some insight into the practicalities of selecting and employing a theoretical sampling strategy. It demonstrates that the credibility of a theory cannot be dissociated from the process by which it has been generated and seeks to encourage and challenge researchers to approach theoretical sampling in a way that is apposite to the core principles of the classic grounded theory methodology.

  8. Structure of small TiC n clusters: A theoretical study

    International Nuclear Information System (INIS)

    Largo, Laura; Cimas, Alvaro; Redondo, Pilar; Rayon, Victor M.; Barrientos, Carmen

    2006-01-01

    A theoretical study of the TiC n (n = 1-8) clusters has been carried out at the B3LYP/6-311+G(d) level. Molecular properties for three different isomers, namely linear, cyclic, and fan species, have been determined. The fan isomers, where the titanium atom is essentially side-bonded to the entire C n unit, are predicted to be more stable than both linear and cyclic isomers. Only for the largest studied species, TiC 8 , the cyclic isomer is located lower in energy. An even-odd parity effect in the incremental binding energies is observed for the three isomers, n-even species being in general more stable for linear and fan isomers, whereas for the cyclic species n-odd clusters are favoured. A topological analysis of the electronic charge density shows that all cyclic isomers correspond to true monocyclic rings, whereas for the fan species a variety of different connectivities has been observed

  9. Theoretical study of a melting curve for tin

    International Nuclear Information System (INIS)

    Feng, Xi; Ling-Cang, Cai

    2009-01-01

    The melting curve of Sn has been calculated using the dislocation-mediated melting model with the 'zone-linking method'. The results are in good agreement with the experimental data. According to our calculation, the melting temperature of γ-Sn at zero pressure is about 436 K obtained by the extrapolation of the method from the triple point of Sn. The results show that this calculation method is better than other theoretical methods for predicting the melting curve of polymorphic material Sn. (condensed matter: structure, thermal and mechanical properties)

  10. Spectroscopic Analysis of Neurotransmitters: A Theoretical and Experimental Raman Study

    Science.gov (United States)

    Alonzo, Matthew

    Surface-enhanced Raman spectroscopy (SERS) was applied to investigate the feasibility in the detection and monitoring of the dopamine (DA) neurotransmitter adsorbed onto silver nanoparticles (Ag NPs) at 10-11 molar, a concentration far below physiological levels. In addition, density functional theory (DFT) calculations were obtained with the Gaussian-09 analytical suite software to generate the theoretical molecular configuration of DA in its neutral, cationic, anionic, and dopaminequinone states for the conversion of computer-simulated Raman spectra. Comparison of theoretical and experimental results show good agreement and imply the presence of dopamine in all of its molecular forms in the experimental setting. The dominant dopamine Raman bands at 750 cm-1 and 795 cm-1 suggest the adsorption of dopaminequinone onto the silver nanoparticle surface. The results of this experiment give good insight into the applicability of using Raman spectroscopy for the biodetection of neurotransmitters.

  11. Substituent effif ects on hydrogen bonding in Watson-Crick base pairs. A theoretical study

    NARCIS (Netherlands)

    Fonseca Guerra, C.; van der Wijst, T.; Bickelhaupt, F.M.

    2005-01-01

    We have theoretically analyzed Watson-Crick AT and GC base pairs in which purine C8 and/or pyrimidine C6 positions carry a substituent X = H, F, Cl or Br, using the generalized gradient approximation (GGA) of density functional theory at BP86/TZ2P. The purpose is to study the effects on structure

  12. CONTENT ANALYSIS, DISCOURSE ANALYSIS, AND CONVERSATION ANALYSIS: PRELIMINARY STUDY ON CONCEPTUAL AND THEORETICAL METHODOLOGICAL DIFFERENCES

    Directory of Open Access Journals (Sweden)

    Anderson Tiago Peixoto Gonçalves

    2016-08-01

    Full Text Available This theoretical essay aims to reflect on three models of text interpretation used in qualitative research, which is often confused in its concepts and methodologies (Content Analysis, Discourse Analysis, and Conversation Analysis. After the presentation of the concepts, the essay proposes a preliminary discussion on conceptual and theoretical methodological differences perceived between them. A review of the literature was performed to support the conceptual and theoretical methodological discussion. It could be verified that the models have differences related to the type of strategy used in the treatment of texts, the type of approach, and the appropriate theoretical position.

  13. Theoretical Study of Triatomic Systems Involving Helium Atoms

    International Nuclear Information System (INIS)

    Suno, H.; Hiyama, E.; Kamimura, M.

    2013-01-01

    The triatomic 4 He system and its isotopic species 4 He 2 3 He are theoretically investigated. By adopting the best empirical helium interaction potentials, we calculate the bound state energy levels as well as the rates for the three-body recombination processes: 4 He + 4 He + 4 He → 4 He 2 + 4 He and 4 He + 4 He + 3 He → 4 He 2 + 3 He. We consider not only zero total angular momentum J = 0 states, but also J > 0 states. We also extend our study to mixed helium-alkali triatomic systems, that is 4 He 2 X with X = 7 Li, 23 Na, 39 K, 85 Rb, and 133 Cs. The energy levels of all the J ≥ 0 bound states for these species are calculated as well as the rates for three-body recombination processes such as 4 He + 4 He + 7 Li → 4 He 2 + 7 Li and 4 He + 4 He + 7 Li → 4 He 7 Li + 4 He. In our calculations, the adiabatic hyperspherical representation is employed but we also obtain preliminary results using the Gaussian expansion method. (author)

  14. Theoretical and experimental study of the dark signal in CMOS image sensors affected by neutron radiation from a nuclear reactor

    Science.gov (United States)

    Xue, Yuanyuan; Wang, Zujun; He, Baoping; Yao, Zhibin; Liu, Minbo; Ma, Wuying; Sheng, Jiangkun; Dong, Guantao; Jin, Junshan

    2017-12-01

    The CMOS image sensors (CISs) are irradiated with neutron from a nuclear reactor. The dark signal in CISs affected by neutron radiation is studied theoretically and experimentally. The Primary knock-on atoms (PKA) energy spectra for 1 MeV incident neutrons are simulated by Geant4. And the theoretical models for the mean dark signal, dark signal non-uniformity (DSNU) and dark signal distribution versus neutron fluence are established. The results are found to be in good agreement with the experimental outputs. Finally, the dark signal in the CISs under the different neutron fluence conditions is estimated. This study provides the theoretical and experimental evidence for the displacement damage effects on the dark signal CISs.

  15. Theoretical study of asymmetric super-rotors: Alignment and orientation

    Science.gov (United States)

    Omiste, Juan J.

    2018-02-01

    We report a theoretical study of the optical centrifuge acceleration of an asymmetric top molecule interacting with an electric static field by solving the time-dependent Schrödinger equation in the rigid rotor approximation. A detailed analysis of the mixing of the angular momentum in both the molecular and the laboratory fixed frames allows us to deepen the understanding of the main features of the acceleration process, for instance, the effective angular frequency of the molecule at the end of the pulse. For the case of the SO2 molecular super-rotor, we show numerically that it rotates around one internal axis and that its dynamics is confined to the plane defined by the polarization axis of the laser, in agreement with experimental findings. Furthermore, we consider the orientation patterns induced by the dc field, showing the characteristics of their structure as a function of the strength of the static field and the initial configuration of the fields.

  16. Theoretical nuclear physics

    CERN Document Server

    Blatt, John M

    1979-01-01

    A classic work by two leading physicists and scientific educators endures as an uncommonly clear and cogent investigation and correlation of key aspects of theoretical nuclear physics. It is probably the most widely adopted book on the subject. The authors approach the subject as ""the theoretical concepts, methods, and considerations which have been devised in order to interpret the experimental material and to advance our ability to predict and control nuclear phenomena.""The present volume does not pretend to cover all aspects of theoretical nuclear physics. Its coverage is restricted to

  17. Theoretical studies of field-reversed configurations (FRC) and experimental study of the FRC during translation

    International Nuclear Information System (INIS)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.

    1985-01-01

    Theoretical studies of FRC stability and transport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in two-dimensional hybrid code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower hybrid drift instability in parameter regimes relevant to experiments show good agreement with a non-local theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a DC solenoid and trapped by magnetic mirrors, has been studied in the FRX-C/T experiment. Efficient transfer of particles, energy and internal magnetic flux are observed with no enhancement of loss processes over in-situ FRC experiments. The axial velocity of the FRC can be estimated reasonably well with a simple model based on conservation of energy. Internal magnetic field probing during translation shows the expected structure of poloidal field and a complex distribution of generally weak toroidal fields. Measurements of radiated power indicate that radiation is a small fraction of the total plasma power loss (typically 8%). Translation has facilitated scaling studies of confinement over a wider range of parameters than were achieved by in-situ FRX-C experiments. For example, the variable xsub(s), the ratio of the separatrix radius to the metal wall radius, has been increased to about 0.7 by allowing the FRC to expand during translation. In all cases, particle confinement times agree within a factor of two with predictions by models that assume a lower hybrid drift resistivity. However, for the conditions studied there are indications that the experimental

  18. Theoretical study of solvent effects on the coil-globule transition

    Science.gov (United States)

    Polson, James M.; Opps, Sheldon B.; Abou Risk, Nicholas

    2009-06-01

    The coil-globule transition of a polymer in a solvent has been studied using Monte Carlo simulations of a single chain subject to intramolecular interactions as well as a solvent-mediated effective potential. This solvation potential was calculated using several different theoretical approaches for two simple polymer/solvent models, each employing hard-sphere chains and hard-sphere solvent particles as well as attractive square-well potentials between some interaction sites. For each model, collapse is driven by variation in a parameter which changes the energy mismatch between monomers and solvent particles. The solvation potentials were calculated using two fundamentally different methodologies, each designed to predict the conformational behavior of polymers in solution: (1) the polymer reference interaction site model (PRISM) theory and (2) a many-body solvation potential (MBSP) based on scaled particle theory introduced by Grayce [J. Chem. Phys. 106, 5171 (1997)]. For the PRISM calculations, two well-studied solvation monomer-monomer pair potentials were employed, each distinguished by the closure relation used in its derivation: (i) a hypernetted-chain (HNC)-type potential and (ii) a Percus-Yevick (PY)-type potential. The theoretical predictions were each compared to results obtained from explicit-solvent discontinuous molecular dynamics simulations on the same polymer/solvent model systems [J. Chem. Phys. 125, 194904 (2006)]. In each case, the variation in the coil-globule transition properties with solvent density is mostly qualitatively correct, though the quantitative agreement between the theory and prediction is typically poor. The HNC-type potential yields results that are more qualitatively consistent with simulation. The conformational behavior of the polymer upon collapse predicted by the MBSP approach is quantitatively correct for low and moderate solvent densities but is increasingly less accurate for higher densities. At high solvent densities

  19. A study of brain networks associated with swallowing using graph-theoretical approaches.

    Directory of Open Access Journals (Sweden)

    Bo Luan

    Full Text Available Functional connectivity between brain regions during swallowing tasks is still not well understood. Understanding these complex interactions is of great interest from both a scientific and a clinical perspective. In this study, functional magnetic resonance imaging (fMRI was utilized to study brain functional networks during voluntary saliva swallowing in twenty-two adult healthy subjects (all females, [Formula: see text] years of age. To construct these functional connections, we computed mean partial correlation matrices over ninety brain regions for each participant. Two regions were determined to be functionally connected if their correlation was above a certain threshold. These correlation matrices were then analyzed using graph-theoretical approaches. In particular, we considered several network measures for the whole brain and for swallowing-related brain regions. The results have shown that significant pairwise functional connections were, mostly, either local and intra-hemispheric or symmetrically inter-hemispheric. Furthermore, we showed that all human brain functional network, although varying in some degree, had typical small-world properties as compared to regular networks and random networks. These properties allow information transfer within the network at a relatively high efficiency. Swallowing-related brain regions also had higher values for some of the network measures in comparison to when these measures were calculated for the whole brain. The current results warrant further investigation of graph-theoretical approaches as a potential tool for understanding the neural basis of dysphagia.

  20. Physical Violence between Siblings: A Theoretical and Empirical Analysis

    Science.gov (United States)

    Hoffman, Kristi L.; Kiecolt, K. Jill; Edwards, John N.

    2005-01-01

    This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have…

  1. 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.

  2. A theoretical study of the alkylation reaction of toluene with methanol catalyzed by acidic mordenite

    NARCIS (Netherlands)

    Vos, A.M.; Rozanska, X.; Schoonheydt, R.A.; Santen, van R.A.; Hutschka, F.; Hafner, J.

    2001-01-01

    A theoretical study of the alkylation reaction of toluene with methanol catalyzed by the acidic Mordenite (Si/Al = 23) is reported. Cluster DFT as well as periodical structure DFT calculations have been performed. Full reaction energy diagrams of the elementary reaction steps that lead to the

  3. Experimental and theoretical study of the electron cascade induced in a gas by laser light

    International Nuclear Information System (INIS)

    Louis-Jacquet, Michel.

    1978-10-01

    In a laser gas interaction experiment, first electrons created by multiphoton ionization of atoms gain sufficient energy in the laser E.M. wave to promote collisional ionization of other atoms. An experimental and theoretical study of the electron-neutral atom inverse bremsstrahlung process and the consecutive electron cascade is presented. The main basic idea is to create an initial electron population and to study its evolution versus the photon density. A Boltzman equation including several collision terms can describe such a plasma. The resolution by a general eigen values method shows that the electron density growth rate is inversely proportionnal to both neutral atom density and laser light illumination. Experimental conditions were defined in order to insure negligible secondary mechanisms (multiphoton ionization, diffusion, recombination, ...). Using a macroscopic description of the interaction, the growth rate can be deduced from the experimental results. Values are in a rather good agreement with the theoretical ones. Moreover evidence is given of influence of the excited atoms on the multiplication process [fr

  4. Theoretical and Experimental Studies of New Polymer-Metal High-Dielectric Constant Nanocomposites

    Science.gov (United States)

    Ginzburg, Valeriy; Elwell, Michael; Myers, Kyle; Cieslinski, Robert; Malowinski, Sarah; Bernius, Mark

    2006-03-01

    High-dielectric-constant (high-K) gate materials are important for the needs of electronics industry. Most polymers have dielectric constant in the range 2 materials with K > 10 it is necessary to combine polymers with ceramic or metal nanoparticles. Several formulations based on functionalized Au-nanoparticles (R ˜ 5 -— 10 nm) and PMMA matrix polymer are prepared. Nanocomposite films are subsequently cast from solution. We study the morphology of those nanocomposites using theoretical (Self-Consistent Mean-Field Theory [SCMFT]) and experimental (Transmission Electron Microscopy [TEM]) techniques. Good qualitative agreement between theory and experiment is found. The study validates the utility of SCMFT as screening tool for the preparation of stable (or at least metastable) polymer/nanoparticle mixtures.

  5. Theoretical studies of Pt-Ti nanoparticles for potential use as PEMFC electrocatalysts.

    Science.gov (United States)

    Jennings, Paul C; Pollet, Bruno G; Johnston, Roy L

    2012-03-07

    A theoretical investigation is presented of alloying platinum with titanium to form binary Pt-Ti nanoalloys as an alternative to the expensive pure platinum catalysts commonly used for Proton Exchange Membrane Fuel Cell cathode electrocatalysts. Density Functional Theory calculations are performed to investigate compositional effects on structural properties as well as Oxygen Reduction Reaction kinetics and poisoning effects. High symmetry A(32)-B(6) clusters are studied to investigate structural properties. From these structures binding energies of hydroxyl and carbon monoxide are studied on a range of sites on the surface of the clusters. Promising results are obtained suggesting that the bimetallic Pt-Ti nanoalloys may exhibit enhanced properties compared to pure platinum catalysts.

  6. Theoretical and experimental studies of heavy liquid metal thermal hydraulics. Proceedings of a technical meeting

    International Nuclear Information System (INIS)

    2006-10-01

    Through the Nuclear Energy Department's Technical Working Group on Fast Reactors (TWG-FR), the IAEA provides a forum for exchange of information on national programmes, collaborative assessments, knowledge preservation, and cooperative research in areas agreed by the Member States with fast reactor and partitioning and transmutation development programmes (e.g. accelerator driven systems (ADS)). Trends in advanced fast reactor and ADS designs and technology development are periodically summarized in status reports, symposia, and seminar proceedings prepared by the IAEA to provide all interested IAEA Member States with balanced and objective information. The use of heavy liquid metals (HLM) is rapidly diffusing in different research and industrial fields. The detailed knowledge of the basic thermal hydraulics phenomena associated with their use is a necessary step for the development of the numerical codes to be used in the engineering design of HLM components. This is particularly true in the case of lead or lead-bismuth eutectic alloy cooled fast reactors, high power particle beam targets and in the case of the cooling of accelerator driven sub-critical cores where the use of computational fluid dynamic (CFD) design codes is mandatory. Periodic information exchange within the frame of the TWG-FR has lead to the conclusion that the experience in HLM thermal fluid dynamics with regard to both the theoretical/numerical and experimental fields was limited and somehow dispersed. This is the case, e.g. when considering turbulent exchange phenomena, free-surface problems, and two-phase flows. Consequently, Member States representatives participating in the 35th Annual Meeting of the TWG-FR (Karlsruhe, Germany, 22-26 April 2002) recommended holding a technical meeting (TM) on Theoretical and Experimental Studies of Heavy Liquid Metal Thermal Hydraulics. Following this recommendation, the IAEA has convened the Technical Meeting on Theoretical and Experimental Studies of

  7. Theoretical study on dynamical planar-chirality switching in checkerboard-like metasurfaces

    Directory of Open Access Journals (Sweden)

    Urade Yoshiro

    2017-01-01

    Full Text Available In this paper, we show that the handedness of a planar chiral checkerboard-like metasurface can be dynamically switched by modulating the local sheet impedance of the metasurface structure. We propose a metasurface design to realize the handedness switching and theoretically analyze its electromagnetic characteristic based on Babinet’s principle. Numerical simulations of the proposed metasurface are performed to validate the theoretical analysis. It is demonstrated that the polarity of asymmetric transmission for circularly polarized waves, which is determined by the planar chirality of the metasurface, is inverted by switching the sheet impedance at the interconnection points of the checkerboard-like structure. The physical origin of the asymmetric transmission is also discussed in terms of the surface current and charge distributions on the metasurface.

  8. The synthesis, characterization and theoretical study of nano tetrabuthylammonium trichloroiodoaluminate (III

    Directory of Open Access Journals (Sweden)

    shahriar Ghammamy

    2012-10-01

    Full Text Available There is provided a nano aluminate complex that has a quaternary ammonium cation. This nano system has an equal molar ratio of Al to N that has been prepared by reaction of an organic salt R+X- such as [(CH34NBr], and a Lewis acid such as AlCl3, compounds. The synthesized compound was characterized by IR, Mass, X-Ray diffraction measurements. In addition, the structure of synthesized compound was optimized at the theoretical level of the Moller-Plesser perturbations of the second order (MP2, with LanL2DZ basis set and molecular specifications such as band length and angle were extracted using Gaussian 98 program. Theoretical data show good agreement with the experimental result.

  9. Experimental and theoretical IR study of methanol and ethanol converson over H-SAPO-34

    NARCIS (Netherlands)

    Hemelsoet, K.L.J.; Ghysels, A.; Mores, D.; De Wispelaere, K.; Van Speybroeck, V.; Weckhuysen, B.M.; Waroquier, M.

    2011-01-01

    Theoretical and experimental IR data are combined to gain insight into the methanol and ethanol conversion over an acidic H-SAPO-34 catalyst. The theoretical simulations use a large finite cluster and the initial physisorption energy of both alcohols is calculated. Dispersive contributions turn out

  10. Experimental and theoretical study on the structure and vibrational spectra of β-2-aminopyridinium dihydrogenphosphate

    Science.gov (United States)

    Çırak, Çağrı; Demir, Selçuk; Ucun, Fatih; Çubuk, Osman

    2011-08-01

    Experimental and theoretical vibrational spectra of β-2-aminopyridinium dihydrogenphosphate (β-2APDP) have been investigated. The FT-IR spectrum of β-2APDP was recorded in the region 4000-400 cm -1. The optimized molecular structure and theoretical vibrational frequencies of β-2APDP have been investigated using ab initio Hartree-Fock (HF) and density functional B3LYP method with 6-311++G(d,p) basis set. The optimized geometric parameters (bond lengths and bond angles) and theoretical frequencies have been compared with the corresponding experimental data and it is found that they agree well with each other. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Furthermore, the used scale factors were obtained from the ratio of the frequency values of the strongest peaks in the experimental and theoretical IR spectra. From the results it was concluded that the B3LYP method is superior to the HF method for the vibrational frequencies.

  11. Inform: Efficient Information-Theoretic Analysis of Collective Behaviors

    Directory of Open Access Journals (Sweden)

    Douglas G. Moore

    2018-06-01

    Full Text Available The study of collective behavior has traditionally relied on a variety of different methodological tools ranging from more theoretical methods such as population or game-theoretic models to empirical ones like Monte Carlo or multi-agent simulations. An approach that is increasingly being explored is the use of information theory as a methodological framework to study the flow of information and the statistical properties of collectives of interacting agents. While a few general purpose toolkits exist, most of the existing software for information theoretic analysis of collective systems is limited in scope. We introduce Inform, an open-source framework for efficient information theoretic analysis that exploits the computational power of a C library while simplifying its use through a variety of wrappers for common higher-level scripting languages. We focus on two such wrappers here: PyInform (Python and rinform (R. Inform and its wrappers are cross-platform and general-purpose. They include classical information-theoretic measures, measures of information dynamics and information-based methods to study the statistical behavior of collective systems, and expose a lower-level API that allow users to construct measures of their own. We describe the architecture of the Inform framework, study its computational efficiency and use it to analyze three different case studies of collective behavior: biochemical information storage in regenerating planaria, nest-site selection in the ant Temnothorax rugatulus, and collective decision making in multi-agent simulations.

  12. Theoretical and experimental studies on in-plane stiffness of integrated container structure

    Directory of Open Access Journals (Sweden)

    Xiaoxiong Zha

    2016-03-01

    Full Text Available This article presents analytical, numerical, and experimental studies on the in-plane stiffness of container buildings. First, based on diaphragm theory, parallel corrugated direction stiffness of corrugated sheet has been deduced, and based on energy method, shear modulus of two elastic principal directions of orthotropic plate has been deduced, and through stiffness conversion method, the stiffness relationship between parallel corrugated direction and vertical corrugated direction has been obtained. Combined with container frame, the container stiffness of loading end and non-loading end, as bottom side beam fixed, has been obtained. Second, through the software Abaqus, full-scale container model has been established. The loading–displacement curve of finite element model has been compared with theoretical analysis and has a good agreement. Third, through 20 and 40 ft container, corresponding experimental verification has been done, and by comparison of container stiffness, the theoretical analysis and finite element simulation have been verified. Finally, based on verified finite element model, parametric analysis of corrugated sheet size, corrugated sheeting cross section, elasticity modulus of top side beam, and every plate action for container stiffness have been given. Research result has made feasible in design and construction of container buildings and can provide some references to corresponding specification preparation.

  13. Status of molten fuel coolant interaction studies and theoretical modelling work at IGCAR

    International Nuclear Information System (INIS)

    Rao, P.B.; Singh, Om Pal; Singh, R.S.

    1994-01-01

    The status of Molten Fuel Coolant Interaction (MFCI) studies is reviewed and some of the important observations made are presented. A new model for MFCI that is developed at IGCAR by considering the various mechanisms in detail is described. The model is validated and compared with the available experimental data and theoretical work at different stages of its development. Several parametric studies that are carried using this model are described. The predictions from this model have been found to be satisfactory, considering the complexity of the MFCI. A need for more comprehensive and MFCI-specific experimental tests is brought out. (author)

  14. Theoretical physics. Quantum mechanics

    International Nuclear Information System (INIS)

    Rebhan, Eckhard

    2008-01-01

    From the first in two comprehensive volumes appeared Theoretical Physics of the author by this after Mechanics and Electrodynamics also Quantum mechanics appears as thinner single volume. First the illustrative approach via wave mechanics is reproduced. The more abstract Hilbert-space formulation introduces the author later by postulates, which are because of the preceding wave mechanics sufficiently plausible. All concepts of quantum mechanics, which contradict often to the intuitive understanding formed by macroscopic experiences, are extensively discussed and made by means of many examples as well as problems - in the largest part provided with solutions - understandable. To the interpretation of quantum mechanics an extensive special chapter is dedicated. this book arose from courses on theoretical physics, which the author has held at the Heinrich-Heine University in Duesseldorf, and was in numerous repetitions fitted to the requirement of the studyings. it is so designed that it is also after the study suited as reference book or for the renewing. All problems are very thoroughly and such extensively studied that each step is separately reproducible. About motivation and good understandability is cared much

  15. The mechanism for the rhodium-catalyzed decarbonylation of aldehydes: A combined experimental and theoretical study

    DEFF Research Database (Denmark)

    Fristrup, Peter; Kreis, Michael; Palmelund, Anders

    2008-01-01

    that similar mechanisms are operating. A DFT (B3LYP) study of the catalytic cycle indicated a rapid oxidative addition into the C(O)-H bond followed by a rate-limiting extrusion of CO and reductive elimination. The theoretical kinetic isotope effects based on this mechanism were in excellent agreement...

  16. Theoretical and Experimental Study on Vibration Propagation in PMMA Components in Ultrasonic Bonding Process

    Directory of Open Access Journals (Sweden)

    Yibo Sun

    2017-03-01

    Full Text Available Ultrasonic bonding has an increasing application in the micro assembly of polymeric micro-electro mechanical systems (MEMS with high requirements for fusion precision. In the ultrasonic bonding process, the propagation of ultrasonic vibration in polymer components is related to the interfacial fusion, which can be used as a monitoring parameter to control ultrasonic energy. To study the vibration propagation in viscoelastic polymer components, finite element analysis on the bonding of poly methyl methacrylate (PMMA micro connector to substrate for microfluidic system is carried out. Curves of propagated vibration amplitude corresponding to interfacial temperatures are obtained. The ultrasonic vibration propagated in PMMA components are measured through experiments. The theoretical and experimental results are contrasted to analyze the change mechanism of vibration propagation related to temperature. Based on the ultrasonic bonding process controlled by the feedback of vibration propagation, interfacial fusions at different vibration propagation states are obtained through experiments. Interfacial fusion behavior is contrasted to the propagated vibration amplitude in theoretical and experimental studies. The relation between vibration propagation and fusion degree is established with the proper parameter range for the obtained high quality bonding.

  17. Semiempirical Theoretical Studies of 1,3-Benzodioxole Derivatives as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    Omnia A. A. El-Shamy

    2017-01-01

    Full Text Available The efficiency of 1,3-benzodioxole derivatives as corrosion inhibitors is theoretically studied using quantum chemical calculation and Quantitative Structure Activity Relationship (QSAR. Different semiempirical methods (AM1, PM3, MNDO, MINDO/3, and INDO are applied in order to determine the relationship between molecular structure and their corrosion protection efficiencies. Different quantum parameters are obtained as the energy of highest occupied molecular orbital EHOMO, the energy of the lowest unoccupied molecular orbital ELUMO, energy gap ΔEg, dipole moment μ, and Mulliken charge on the atom. QSAR approach is applied to elucidate some important parameters as the hydrophobicity (Log P, surface area (S.A, polarization (P, and hydration energy (EHyd.

  18. Theoretical studies of field-reversed configurations (FRCs) and experimental study of the FRC during translation

    Energy Technology Data Exchange (ETDEWEB)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.; Klingner, P.L.; Linford, R.K.; McKenna, K.F.; Rej, D.J.; Schwarzmeier, J.L.; Sgro, A.; Sherwood, E.G.

    1984-08-01

    Theoretical studies of FRC stability and tranport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in 2-dimensional hybrid-code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower-hybrid-drift instability in parameter regimes relevant to experiments show good agreement with a nonlocal theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a dc solenoid, and trapped by magnetic mirrors has been studied in the FRX-C/T experiment.

  19. Theoretical studies of field-reversed configurations (FRCs) and experimental study of the FRC during translation

    International Nuclear Information System (INIS)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.

    1984-08-01

    Theoretical studies of FRC stability and tranport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in 2-dimensional hybrid-code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower-hybrid-drift instability in parameter regimes relevant to experiments show good agreement with a nonlocal theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a dc solenoid, and trapped by magnetic mirrors has been studied in the FRX-C/T experiment

  20. Exploring Occupational and Behavioral Risk Factors for Obesity in Firefighters: A Theoretical Framework and Study Design

    Directory of Open Access Journals (Sweden)

    BongKyoo Choi

    2011-12-01

    Full Text Available Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US. However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupational and behavioral risk factors in the development of obesity in firefighters enrolled in the Orange County Fire Authority Wellness Fitness Program. The study plan will be described with emphasis on its methodological merits: adopting a participatory action research approach, developing a firefighter-specific work and health questionnaire, conducting both a cross-sectional epidemiological study using the questionnaire and a sub-study to assess the validity of the questionnaire with dietary intake and physical activity measures, and evaluating the strengths and weaknesses of the body mass index as an obesity measure in comparison to skinfold-based percent body fat. The study plan based on a theoretical framework can be an essential first step for establishing effective intervention programs for obesity among professional and voluntary firefighters.

  1. Theoretical Studies of the Electronic Structure of the Compounds of the Actinide Elements

    International Nuclear Information System (INIS)

    Kaltsoyannis, Nikolas; Hay, P.J.; Li, Jun; Blaudeau, Jean-Philippe; Bursten, Bruce E.

    2006-01-01

    In this chapter, we will present an overview of the theoretical and computational developments that have increased our understanding of the electronic structure of actinide-containing molecules and ions. The application of modern electronic structure methodologies to actinide systems remains one of the great challenges in quantum chemistry; indeed, as will be discussed below, there is no other portion of the periodic table that leads to the confluence of complexity with respect to the calculation of ground- and excited-state energies, bonding descriptions, and molecular properties. But there is also no place in the periodic table in which effective computational modeling of electronic structure can be more useful. The difficulties in creating, isolating, and handling many of the actinide elements provide an opportunity for computational chemistry to be an unusually important partner in developing the chemistry of these elements. The importance of actinide electronic structure begins with the earliest studies of uranium chemistry and predates the discovery of quantum mechanics. The fluorescence of uranyl compounds was observed as early as 1833, a presage of the development of actinometry as a tool for measuring photochemical quantum yields. Interest in nuclear fuels has stimulated tremendous interest in understanding the properties, including electronic properties, of small actinide-containing molecules and ions, especially the oxides and halides of uranium and plutonium. The synthesis of uranocene in 1968 led to the flurry of activity in the organometallic chemistry of the actinides that continues today. Actinide organometallics (or organoactinides) are nearly always molecular systems and are often volatile, which makes them amenable to an arsenal of experimental probes of molecular and electronic structure (Marks and Fischer, 1979). Theoretical and computational studies of the electronic structure of actinide systems have developed in concert with the experimental

  2. Corrosion Inhibition of Copper-nickel Alloy: Experimental and Theoretical Studies

    Energy Technology Data Exchange (ETDEWEB)

    Khadom, Anees A. [Univ. of Daiyla, Baquba (Iran, Islamic Republic of); Yaro, Aprael S. [Univ. of Baghdad, Aljadreaa (Iran, Islamic Republic of); Musa, Ahmed Y.; Mohamad, Abu Bakar; Kadhum, Abdul Amir H. [UniversitiKebangsaan Malaysia, Bangi (Malaysia)

    2012-08-15

    The corrosion inhibition of copper-nickel alloy by Ethylenediamine (EDA) and Diethylenetriamine (DETA) in 1.5M HCl has been investigated by weight loss technique at different temperatures. Maximum value of inhibitor efficiency was 75% at 35 .deg. C and 0.2 M inhibitor concentration EDA, while the lower value was 4% at 35 .deg. C and 0.01 M inhibitor concentration DETA. Two mathematical models were used to represent the corrosion rate data, second order polynomial model and exponential model respectively. Nonlinear regression analysis showed that the first model was better than the second model with high correlation coefficient. The reactivity of studied inhibitors was analyzed through theoretical calculations based on density functional theory (DFT). The results showed that the reactive sites were located on the nitrogen (N1, N2 and N4) atoms.

  3. Theoretical and Experimental Study on Secondary Piezoelectric Effect Based on PZT-5

    International Nuclear Information System (INIS)

    Zhang, Z H; Sun, B Y; Shi, L P

    2006-01-01

    The purpose of this paper is to confirm the existence of secondary and multiple piezoelectric effect theoretically and experimentally. Based on Heckmann model showing the relationship among mechanical, electric and heat energy and the physical model on mechanical, electric, heat, and magnetic energy, theoretical analysis of multiple piezoelectric effect is made through four kinds of piezoelectric equations. Experimental research of secondary direct piezoelectric effect is conducted through adopting PZT-5 piles. The result of the experiment indicates that charge generated by secondary direct piezoelectric effect as well as displacement caused by first converse piezoelectric effect keeps fine linearity with the applied voltage

  4. Status of the theoretical study of microwave heating in EBT

    International Nuclear Information System (INIS)

    Batchelor, D.B.

    1978-09-01

    The basic strategy of the theoretical study of microwave heating in the ELMO Bumpy Torus (EBT) is outlined and the current status of the various aspects of the study is described. There are four broad areas which are being investigated: (1) heating and wave damping mechanisms, (2) the geometrical optics of microwave propagation in EBT, (3) reflection and mode conversion effects at regions such as cutoff and resonances where the geometrical optics approximation breaks down, and (4) nonlinear effects such as ponderamotive effects and parametric decay. Details are given of the geometrical optics code which has been developed to do ray tracing in arbitrary three dimensional (3-D) plasma equilibria. Examples are given for plasma parameters characteristic of EBT-I and EBT-II. Details are also given of the stochastic heating model currently in use with the 1-D transport code and of the linear wave damping model used in the ray tracing code. The most pressing problems of physics yet to be addressed and the directions for future work are indicated

  5. A theoretical study for thorium monocarbide (ThC)

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, S.; Tatar, A. [Gazi University, Department of Physics, Teknikokullar 06500, Ankara (Turkey); Ciftci, Y.O., E-mail: yasemin@gazi.edu.tr [Gazi University, Department of Physics, Teknikokullar 06500, Ankara (Turkey)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We focused on high pressure behavior of ThC. Black-Right-Pointing-Pointer ThC is metallic, and mechanically stable. Black-Right-Pointing-Pointer The obtained results agree with the other available values. Black-Right-Pointing-Pointer ThC is hard material, and hardness increases properly with pressure. - Abstract: The structural, mechanical, electronic and thermodynamic properties of thorium monocarbide (ThC) with NaCl-type structure have been investigated by using first-principles plane wave density functional calculations with GGA, LDA and LDA + U functionals. It is shown that calculated equilibrium structural parameters of ThC are in agreement with the experimental results. It is seen from calculated single-crystal elastic constants that ThC with NaCl-type structure is mechanically stable. And from calculated density of states and band structure, it is observed that ThC is metallic. After the properties at 0 GPa are clarified, pressure dependency of the structural parameters, the elastic properties and related mechanical properties, density of states (DOS) and hardness are studied. Furthermore, the thermodynamic properties of ThC are obtained from the quasi-harmonic Debye model (QHM) over high pressure and temperature ranges for three functionals. The results are compared to each other, and the available experimental and theoretical data.

  6. A theoretical study for thorium monocarbide (ThC)

    International Nuclear Information System (INIS)

    Aydin, S.; Tatar, A.; Ciftci, Y.O.

    2012-01-01

    Highlights: ► We focused on high pressure behavior of ThC. ► ThC is metallic, and mechanically stable. ► The obtained results agree with the other available values. ► ThC is hard material, and hardness increases properly with pressure. - Abstract: The structural, mechanical, electronic and thermodynamic properties of thorium monocarbide (ThC) with NaCl-type structure have been investigated by using first-principles plane wave density functional calculations with GGA, LDA and LDA + U functionals. It is shown that calculated equilibrium structural parameters of ThC are in agreement with the experimental results. It is seen from calculated single-crystal elastic constants that ThC with NaCl-type structure is mechanically stable. And from calculated density of states and band structure, it is observed that ThC is metallic. After the properties at 0 GPa are clarified, pressure dependency of the structural parameters, the elastic properties and related mechanical properties, density of states (DOS) and hardness are studied. Furthermore, the thermodynamic properties of ThC are obtained from the quasi-harmonic Debye model (QHM) over high pressure and temperature ranges for three functionals. The results are compared to each other, and the available experimental and theoretical data.

  7. Optical activity in planar chiral metamaterials: Theoretical study

    International Nuclear Information System (INIS)

    Bai, Benfeng; Svirko, Yuri; Turunen, Jari; Vallius, Tuomas

    2007-01-01

    A thorough theoretical study of the optical activity in planar chiral metamaterial (PCM) structures, made of both dielectric and metallic media, is conducted by the analysis of gammadion-shaped nanoparticle arrays. The general polarization properties are first analyzed from an effective-medium perspective, by analogy with natural optical activity, and then verified by rigorous numerical simulation, some of which are corroborated by previous experimental results. The numerical analysis suggests that giant polarization rotation (tens of degrees) may be achieved in the PCM structures with a thickness of only hundreds of nanometers. The artificial optical activity arises from circular birefringence induced by the structural chirality and is enhanced by the guided-mode or surface-plasmon resonances taking place in the structures. There are two polarization conversion types in the dielectric PCMs, whereas only one type in the metallic ones. Many intriguing features of the polarization property of PCMs are also revealed and explained: the polarization effect is reciprocal and vanishes in the symmetrically layered structures; the effect occurs only in the transmitted field, but not in the reflected field; and the polarization spectra of two enantiomeric PCM structures are mirror symmetric to each other. These remarkable properties pave the way for the PCMs to be used as polarization elements in new-generation integrated optical systems

  8. Aims and theoretical frameworks in nursing students' Bachelor's theses in Sweden: A descriptive study.

    Science.gov (United States)

    Silén, Marit; Johansson, Linda

    2016-02-01

    Nursing students' independent projects in Sweden not only provide an opportunity to receive a professional qualification as a nurse but also gain a Bachelor's degree in nursing. The aim of these projects is to demonstrate knowledge and understanding within the major field of the education. This study aimed to describe and analyze the topics as well as theoretical frameworks and concepts in nursing students' independent projects, which lead to a Bachelor's degree, in a Swedish context. A total of 491 independent projects, written by nursing students in Sweden, were included in the study. Topics together with theoretical frameworks and concepts in the projects were identified. Similar topics and theoretical frameworks and concepts, respectively, were grouped into subcategories, and similar subcategories were then merged into a main category. The number of entries in each category was counted for descriptive statistics in order to allow for the demonstration of magnitude. The most common topics concerned experiences and managing when having an illness, experiences of care and of being a caregiver, and healthcare staff's care and knowledge. The nursing theories/models that were most often used were Eriksson's Theory of Caritative Caring, Travelbee's Human-to-Human Relationship Model, and Orem's Self-care Theory. Among the non-nursing theories/models, perspectives and concepts lifeworld, ethical values and principles, existential concepts and quality of life/health-related quality of life, were most often used by these students. There may be some difficulty in finding a topic for the project that is relevant for both a professional qualification as a nurse, as well as for achieving the requirements of a Bachelor's degree in nursing. The study indicates that there is a need to widen the student's understanding of different nursing theories/perspectives/models/concepts during nursing education so that students are familiar with a broad range of these when conducting their

  9. Experimental and theoretical studies of a pyrazole-thiazolidin-2,4-di-one hybrid

    Science.gov (United States)

    Mushtaque, Md.; Avecilla, Fernando; Haque, Ashanul; Perwez, Ahmad; Khan, Md. Shahzad; Rizvi, M. Moshahid Alam

    2017-08-01

    The present work describes synthesis, characterization and biological evaluations of a hybrid compound 10 composed of two intriguing scaffolds pyrazole and thiazolidin-2,4-di-one. The title compound was obtained via multi-step reaction and characterized by a number of techniques (viz. IR, UV-Visible, 1H-NMR, 13C-NMR and MS) including X-ray crystallography. The structural and photophysical data of compound 10 were well supported by theoretical calculations performed at density functional (DFT) level. In-vitro anticancer studies on different human cancer cell lines indicated moderate to low activity of the compounds. The molecular target of the compound was predicted through in-silico studies. Finding of the studies are presented herein.

  10. Theoretical physics

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The nuclear theory program deals with the properties of nuclei and with the reactions and interactions between nuclei and a variety of projectiles. The main areas of concentration are: heavy-ion direct reactions at nonrelativistic energies; nuclear shell theory and nuclear structure; nuclear matter and nuclear forces;intermediate-energy physics and pion-nucleus interactions; and high-energy collisions of heavy ions. Recent progress and plans for future work in these five main areas of concentration and a summary of other theoretical studies currently in progress or recently completed are presented

  11. Theoretical studies on the catalytic oxidation of carbon monoxide on nickel clusters

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, A.K.; Kojima, I.; Miyazaki, E.

    1986-01-01

    Complete neglect of differential overlap (CNDO) molecular orbital calculations using the method of Anno and Sakai for the evaluation of the valence orbital ionization potential (VOIP) were performed with the aim of studying the oxidation of carbon monoxide on nickel clusters. A cluster surface was assumed to be preadsorbed with oxygen and the variation of various bond energies with the approach of a carbon monoxide molecule was studied for different models. Various possibilities for the reaction path are discussed in the light of the theoretical findings and it is suggested that at a low coverage of oxygen the reaction may follow a Langmuir-Hinshelwood path, whereas at a high coverage, an Eley-Rideal path might be more probable. 55 references, 13 figures.

  12. The dynamics of alliances. A game theoretical approach

    NARCIS (Netherlands)

    Ridder, A. de

    2007-01-01

    In this dissertation, Annelies de Ridder presents a game theoretical approach to strategic alliances. More specifically, the dynamics of and within alliances have been studied. To do so, four new models have been developed in the game theoretical tradition. Both coalition theory and strategic game

  13. Computational and theoretical studies of globular proteins

    Science.gov (United States)

    Pagan, Daniel L.

    Protein crystallization is often achieved in experiment through a trial and error approach. To date, there exists a dearth of theoretical understanding of the initial conditions necessary to promote crystallization. While a better understanding of crystallization will help to create good crystals suitable for structure analysis, it will also allow us to prevent the onset of certain diseases. The core of this thesis is to model and, ultimately, understand the phase behavior of protein particles in solution. Toward this goal, we calculate the fluid-fluid coexistence curve in the vicinity of the metastable critical point of the modified Lennard-Jones potential, where it has been shown that nucleation is increased by many orders of magnitude. We use finite-size scaling techniques and grand canonical Monte Carlo simulation methods. This has allowed us to pinpoint the critical point and subcritical region with high accuracy in spite of the critical fluctuations that hinder sampling using other Monte Carlo techniques. We also attempt to model the phase behavior of the gamma-crystallins, mutations of which have been linked to genetic cataracts. The complete phase behavior of the square well potential at the ranges of attraction lambda = 1.15 and lambda = 1.25 is calculated and compared with that of the gammaII-crystallin. The role of solvent is also important in the crystallization process and affects the phase behavior of proteins in solution. We study a model that accounts for the contribution of the solvent free-energy to the free-energy of globular proteins. This model allows us to model phase behavior that includes solvent.

  14. Theoretical and experimental studies of runaway electrons in the TEXTOR tokamak

    International Nuclear Information System (INIS)

    Abdullaev, S.S.; Finken, K.H.; Wongrach, K.; Willi, O.

    2016-01-01

    Theoretical and experimental studies of runaway electrons in tokamaks and their mitigations, particularly the recent studies performed by a group of the Heinrich-Heine University Duesseldorf in collaboration with the Institute of Energy and Climate Research of the Research Centre (Forschungszentrum) of Juelich are reviewed. The main topics focus on (i) runaway generation mechanisms, (ii) runaway orbits in equilibrium plasma, (iii) transport in stochastic magnetic fields, (iv) diagnostics and investigations of transport of runaway electron and their losses in low density discharges (v) runaway electrons during plasma disruptions, and (vi) runaway mitigation methods. The development of runaway diagnostics enables the measurement of runaway electrons in both the centre and edge of the plasma. The diagnostics provide an absolute runaway energy resolved measurement, the radial decay length of runaway electrons and, the structure and dynamics of runaway electron beams. The new mechanism of runaway electron formation during plasma disruptions is discussed.

  15. Theoretical and experimental studies of runaway electrons in the TEXTOR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Abdullaev, S.S.; Finken, K.H.; Wongrach, K.; Willi, O.

    2016-07-01

    Theoretical and experimental studies of runaway electrons in tokamaks and their mitigations, particularly the recent studies performed by a group of the Heinrich-Heine University Duesseldorf in collaboration with the Institute of Energy and Climate Research of the Research Centre (Forschungszentrum) of Juelich are reviewed. The main topics focus on (i) runaway generation mechanisms, (ii) runaway orbits in equilibrium plasma, (iii) transport in stochastic magnetic fields, (iv) diagnostics and investigations of transport of runaway electron and their losses in low density discharges (v) runaway electrons during plasma disruptions, and (vi) runaway mitigation methods. The development of runaway diagnostics enables the measurement of runaway electrons in both the centre and edge of the plasma. The diagnostics provide an absolute runaway energy resolved measurement, the radial decay length of runaway electrons and, the structure and dynamics of runaway electron beams. The new mechanism of runaway electron formation during plasma disruptions is discussed.

  16. Theoretical studies of flash x-ray diagnostics for fuel motion experiments

    International Nuclear Information System (INIS)

    Halbleib, J.A. Sr.; Phillips, A.R.

    1975-09-01

    The results of preliminary theoretical studies concerning the possible employment of short-pulse, high-current field emission diodes as sources for the flash x-ray diagnostics of fuel-pin motion are reported. The predicted thick-target photon environments are obtained from state-of-the-art coupled electron/photon transport models. Through qualitative figures of merit these environments are used to study the importance of source current and voltage. For a selected experimental configuration a comparison is made between the absolute flash x-ray imaging signals predicted for these environments and Monte Carlo/analytic calculations of absolute fission-gamma backgrounds. These preliminary data suggest that field emission sources operating at voltages in the 1-to 5-MeV range and at currents of the order of 100-kA or greater may be adequate diagnostic sources for test-pin configurations as complex as a full LMFBR subassembly

  17. Experimental and theoretical study of bound and quasibound states of Ce{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Walter, C. W.; Gibson, N. D.; Li, Y.-G.; Matyas, D. J.; Alton, R. M.; Lou, S. E.; Field, R. L. III; Hanstorp, D.; Pan, Lin; Beck, Donald R. [Department of Physics and Astronomy, Denison University, Granville, Ohio 43023 (United States); Department of Physics, University of Gothenburg, SE-412 96 Gothenburg (Sweden); Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

    2011-09-15

    The negative ion of cerium is investigated experimentally with tunable infrared laser photodetachment spectroscopy and theoretically with relativistic configuration interaction in the continuum formalism. The relative cross section for neutral atom production is measured with a crossed ion-beam-laser-beam apparatus over the photon energy range of 0.54-0.75 eV. A rich resonance spectrum is revealed near the threshold with, at least, 12 peaks observed due to transitions from bound states of Ce{sup -} to either bound or quasibound excited states of the negative ion. Theoretical calculations of the photodetachment cross sections enable identification of the transitions responsible for the measured peaks. Two of the peaks are due to electric dipole-allowed bound-bound transitions in Ce{sup -}, making cerium only the second atomic negative ion that has been demonstrated to support multiple bound states of opposite parity. In addition, combining the experimental data with the theoretical analysis determines the electron affinity of cerium to be 0.628(10) eV and the fine structure splitting of the ground state of Ce{sup -} ({sup 4} H{sub 7/2}-{sup 4} H{sub 9/2}) to be 0.097 75(4) eV.

  18. Charge transfer through DNA/DNA duplexes and DNA/RNA hybrids: complex theoretical and experimental studies.

    Science.gov (United States)

    Kratochvílová, Irena; Vala, Martin; Weiter, Martin; Špérová, Miroslava; Schneider, Bohdan; Páv, Ondřej; Šebera, Jakub; Rosenberg, Ivan; Sychrovský, Vladimír

    2013-01-01

    Oligonucleotides conduct electric charge via various mechanisms and their characterization and understanding is a very important and complicated task. In this work, experimental (temperature dependent steady state fluorescence spectroscopy, time-resolved fluorescence spectroscopy) and theoretical (Density Functional Theory) approaches were combined to study charge transfer processes in short DNA/DNA and RNA/DNA duplexes with virtually equivalent sequences. The experimental results were consistent with the theoretical model - the delocalized nature of HOMO orbitals and holes, base stacking, electronic coupling and conformational flexibility formed the conditions for more effective short distance charge transfer processes in RNA/DNA hybrids. RNA/DNA and DNA/DNA charge transfer properties were strongly connected with temperature affected structural changes of molecular systems - charge transfer could be used as a probe of even tiny changes of molecular structures and settings. © 2013. Published by Elsevier B.V. All rights reserved.

  19. Thermodynamic properties and equilibrium constant of chemical reaction in nanosystem: An theoretical and experimental study

    International Nuclear Information System (INIS)

    Du, Jianping; Zhao, Ruihua; Xue, Yongqiang

    2012-01-01

    Highlights: ► There is an obvious influence of the size on thermodynamic properties for the reaction referring nano-reactants. ► Gibbs function, enthalpy, entropy and equilibrium constant are dependent on the reactant size. ► There is an approximate linear relation between them. - Abstract: The theoretical relations of thermodynamic properties, the equilibrium constant and reactant size in nanosystem are described. The effects of size on thermodynamic properties and the equilibrium constant were studied using nanosize zinc oxide and sodium bisulfate solution as a reaction system. The experimental results indicated that the molar Gibbs free energy, the molar enthalpy and the molar entropy of the reaction decrease, but the equilibrium constant increases with decreasing reactant size. Linear trends were observed between the reciprocal of size for nano-reactant and thermodynamic variable, which are consistent with the theoretical relations.

  20. FEELINGS OF INSECURITY IN CONTEXT: THEORETICAL PERSPECTIVES FOR STUDYING FEAR OF CRIME IN LATE LIFE

    Directory of Open Access Journals (Sweden)

    Liesbeth De Donder

    2009-01-01

    Full Text Available This paper broadens theoretical perspectives on fear of crime in late life by exploring the concept against the backdrop of a changing society. Since the emergence of the first studies that address fear of crime in late life, research overemphasizes the search for related independent variables being heedless of a thorough theoretical framework. Recent researchers, however, perceive the construct of ‘fear of crime’ as an ‘umbrella’ concept, which encompasses crime related fear and more diffuse ‘feelings of insecurity’. In response to a lack of macro-theorizing, this article illuminates some of the most important characteristics and descriptions of contemporary societies that are relevant to fear of crime. It is shown that in relation to fear of crime, the macro-level of society can be conceptualized as having four important ambivalences. In conclusion, the article

  1. Theoretical and experimental studies of the magnetic fields of Rotamak discharge

    International Nuclear Information System (INIS)

    Kirolous, H.

    1986-12-01

    In part I of this thesis, the self-generated bi-directional toroidal magnetic field structure which has been observed to exist in previous rotamak discharges is theoretically investigated. A possible explanation for the existence of this self-generated field, which relies on the presence of screening currents in the plasma, is advanced. Experimental studies of the magnetic field structure of a rotamak plasma configuration generated and sustained in a metal discharge vessel by means of a rotating magnetic field are described in part II. The rotating magnetic field was produced by feeding radio frequency (r.f.) currents, dephased by 90 degrees, through two orthogonal coils which were located inside the metal chamber. High power amplifiers were used to supply the r.f. current pulses. The efficiency of the r.f. power transfer to the plasma was maximized by using impedance matching networks. The effect on the rotating magnetic field of eddy currents induced in the conducting vessel has been theoretically and experimentally investigated. Extensive magnetic field measurements have been undertaken on one particular rotamak discharge. Measurements of the penetration of the rotating magnetic field into the plasma were made at various axial positions. The steady magnetic field structure was measured at a matrix of 2640 points and a two dimensional least square polynomial fitting algorithm was used to smooth the measured data. This fitting procedure enabled reliable plots of the poloidal flux and current density contours to be constructed. An attempt has been made to apply MHD equilibrium theory to the observed plasma/field configuration. 23 refs., 99 figs., ills

  2. Experimental and theoretical study on forced convection film boiling heat transfer

    International Nuclear Information System (INIS)

    Liu, Qiusheng

    2001-01-01

    Theoretical solutions of forced convection film boiling heat transfer from horizontal cylinders in saturated liquids were obtained based on a two-phase laminar boundary layer film boiling model. It was clarified that author's experimental data for the cylinders with the nondimensional diameters, D, of around 1.3 in water and in Freon-113 agreed with the values of theoretical numerical solutions based on the two-phase laminar boundary layer model with the smooth vapor-liquid interface except those for low flow velocities. A forced convection film boiling heat transfer correlation including the radiation contribution from the cylinders with various diameters in saturated and subcooled liquids was developed based on the two-phase laminar boundary layer film boiling model and the experimental data for water and Freon-113 at wide ranges of flow velocities, surface superheats, system pressures and cylinder diameters. (author)

  3. Towards A Theoretical Biology: Reminiscences

    Indian Academy of Sciences (India)

    engaged in since the start of my career at the University of Chicago. Theoretical biology was ... research on theoretical problems in biology. Waddington, an ... aimed at stimulating the development of such a theoretical biology. The role the ...

  4. Theoretical study of the reaction kinetics of atomic bromine with tetrahydropyran

    KAUST Repository

    Giri, Binod; Lo, John M H; Roscoe, John M.; Alquaity, Awad; Farooq, Aamir

    2015-01-01

    A detailed theoretical analysis of the reaction of atomic bromine with tetrahydropyran (THP, C5H10O) was performed using several ab initio methods and statistical rate theory calculations. Initial geometries of all species involved in the potential

  5. THEORETICAL AND METHODOLOGICAL BASIS OF THE STUDY OF ENVIRONMENTAL AUDIT IN KAZAKHSTAN

    Directory of Open Access Journals (Sweden)

    V. Berezuyuk

    2014-12-01

    Full Text Available Practical problems of modern economic development of the country are associated with unresolved major theoretical issues in the field of auditing. One of them, in our opinion, is to determine the status of the audit as a form of scientific knowledge. This, in turn, requires a clear definition of the subject of audit, missing not only in domestic but also foreign economic literature. Theoretical study of the content and scope of the audit showed that there are different interpretations of this concept in the countries with developed market economies (US, UK and the Kazakhstan legislation. Analysis of multiple interpretations and definitions revealed a narrow view of the audit activities in Kazakhstan legislation. In order to improve the efficiency of the audit work is recommended management of large and medium-sized organizations use simulation methods, structural analysis and design based on the Conditional Split of the company business processes, sub-processes, procedures, functions, etc., which, ultimately, will allow Sort already performed the action and determine the need for the implementation of new procedures or functions aimed at improving the quality of the audit. Each audit organization yourself looking for ways to improve the quality of solutions using a variety of techniques, using the experience and creating in-house auditing standards, in particular, for the effective planning of the audit.

  6. Theoretical and experimental study of electroporation of red blood cells using MEMS technology

    KAUST Repository

    Deng, Peigang; Yin, Guangyao; Zhang, Tong Yi; Chang, Donald C.; Lee, Yi Kuen

    2010-01-01

    A theoretical and experimental study of electroporation (EP) of red blood cells (RBCs) was presented in this paper. With additional strain energy, an energy-based model of an electropore induced on a RBC's membrane at different electric fields was proposed to predict the critical EP electric field strength. In addition, EP experiments with red blood cells at single-cell level was carried out on a micro EP chip. The measured critical EP electric field strengths are in agreement with the numerical predictions. ©2010 IEEE.

  7. Theoretical and experimental study of electroporation of red blood cells using MEMS technology

    KAUST Repository

    Deng, Peigang

    2010-01-01

    A theoretical and experimental study of electroporation (EP) of red blood cells (RBCs) was presented in this paper. With additional strain energy, an energy-based model of an electropore induced on a RBC\\'s membrane at different electric fields was proposed to predict the critical EP electric field strength. In addition, EP experiments with red blood cells at single-cell level was carried out on a micro EP chip. The measured critical EP electric field strengths are in agreement with the numerical predictions. ©2010 IEEE.

  8. Combined experimental and theoretical study on the Raman and Raman optical activity signatures of pentamethylundecane diastereoisomers.

    Science.gov (United States)

    Drooghaag, Xavier; Marchand-Brynaert, Jacqueline; Champagne, Benoît; Liégeois, Vincent

    2010-09-16

    The synthesis and the separation of the four stereoisomers of 2,4,6,8,10-pentamethylundecane (PMU) are described together with their characterization by Raman spectroscopy. In parallel, theoretical calculations of the Raman and vibrational Raman optical activity (VROA) spectra are reported and analyzed in relation with the recorded spectra. A very good agreement is found between the experimental and theoretical spectra. The Raman spectra are also shown to be less affected by the change of configuration than the VROA spectra. Nevertheless, by studying the overlap between the theoretical Raman spectra, we show clear relationships between the spectral fingerprints and the structures displaying a mixture of the TGTGTGTG conformation of the (4R,6s,8S)-PMU (isotactic compound) with the TTTTTTTT conformation of the (4R,6r,8S)-PMU (syndiotactic compound). Then, the fingerprints of the VROA spectra of the five conformers of the (4R,8R)-PMU have been related to the fingerprints of the regular (TG)(N) isotactic compound as a function of the torsion angles. Since the (TT)(N) syndiotactic compound has no VROA signatures, the VROA spectroscopy is very sensitive to the helical structures, as demonstrated here.

  9. Theoretical and experimental study of the vibrational excitations in ethane monolayers adsorbed on graphite (0001) surfaces

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Taub, H.

    1987-01-01

    The collective vibrational excitations of two different crystalline monolayer phases of ethane (C2H6) adsorbed on the graphite (0001) surface have been investigated theoretically and experimentally. The monolayer phases studied are the commensurate 7/8 ×4 structure in which the ethane molecules lie...

  10. An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

    Energy Technology Data Exchange (ETDEWEB)

    Svelle, Stian

    2004-07-01

    The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the

  11. A New Theoretical Approach to Single-Molecule Fluorescence Optical Studies of RNA Dynamics

    International Nuclear Information System (INIS)

    Zhao Xinghai; Shan Guangcun; Bao Shuying

    2011-01-01

    Single-molecule fluorescence spectroscopy in condensed phases has many important chemical and biological applications. The single-molecule fluorescence measurements contain information about conformational dynamics on a vast range of time scales. Based on the data analysis protocols methodology proposed by X. Sunney Xie, the theoretical study here mainly focuses on the single-molecule studies of single RNA with interconversions among different conformational states, to with a single FRET pair attached. We obtain analytical expressions for fluorescence lifetime correlation functions that relate changes in fluorescence lifetime to the distance-dependent FRET mechanism within the context of the Smoluchowski diffusion model. The present work establishes useful guideline for the single-molecule studies of biomolecules to reveal the complicated folding dynamics of single RNA molecules at nanometer scale.

  12. Synthesis, crystal growth, characterization and theoretical studies of 4-aminobenzophenonium picrate

    Science.gov (United States)

    Aditya Prasad, A.; Muthu, K.; Rajasekar, M.; Meenatchi, V.; Meenakshisundaram, S. P.

    2015-01-01

    Single crystals of 4-aminobenzophenonium picrate (4ABPP) were grown by slow evaporation of a mixed solvent system methanol-acetone (1:1,v/v) containing equimolar quantities of picric acid and 4-aminobenzophenone. The proton and carbon signals are confirmed by nuclear magnetic resonance spectroscopy. The various functional groups present in the molecule are identified by FT-IR analysis. Optimized geometry, first-order molecular hyperpolarizability (β), polarizability (α), bond length, bond angles and excited state energy from theoretical UV were derived by Hartree-Fock calculations. The complete assignment of the vibrational modes for 4-aminobenzophenonium picrate was performed by the scaled quantum mechanics force field (SQMFF) methodology using potential energy distribution. Natural bond orbital (NBO) calculations were employed to study the stabilities arising from charge delocalization and intermolecular interactions of 4ABPP. The atomic charge distributions of the various atoms present in 4ABPP are obtained by Mulliken charge population analysis. The as-grown crystal is further characterized by thermal and optical absorbance studies.

  13. Matrix-isolation FT-IR spectra and theoretical study of dimethyl sulfate

    Science.gov (United States)

    Borba, Ana; Gómez-Zavaglia, Andrea; Simões, Pedro N. N. L.; Fausto, Rui

    2005-05-01

    The preferred conformations of dimethyl sulfate and their vibrational spectra were studied by matrix-isolation FT-IR spectroscopy and theoretical methods (DFT and MP2, with basis sets of different sizes, including the quadruple-zeta, aug-cc-pVQZ basis). Conformer GG (of C 2 symmetry and exhibiting O sbnd S sbnd O sbnd C dihedral angles of 74.3°) was found to be the most stable conformer in both the gaseous phase and isolated in argon. Upon annealing of the matrix, the less stable observed conformer (GT; with C 1 symmetry) quickly converts to the GG conformer, with the resulting species being embedded in a matrix-cage which corresponds to the most stable matrix-site for GG form. The highest energy TT conformer, which was assumed to be the most stable conformer in previous studies, is predicted by the calculations to have a relative energy of ca. 10 kJ mol -1 and was not observed in the spectra of the matrix-isolated compound.

  14. The formation and quenching of positronium in solution: some theoretical and experimental studies

    International Nuclear Information System (INIS)

    Beling, C.D.

    1981-05-01

    Reviews are made of the present theoretical knowledge of the formation and quenching of positronium in solution. Formation is described on both the Ore model and the spur model. Quenching via pickoff and chemical processes is considered. The uncertainties that are presently found in the theoretical modelling are considered. Experimentally the positron lifetime technique is used in which positrons are emitted from a vitrified 22 Na source. The lifetime spectrum is obtained conventionally and is analysed by a modified form of the program POSITRONFIT EXTENDED. (author)

  15. Epidemiology of a thermonuclear bomb-burst over Nashville, Tennessee: a theoretic study

    International Nuclear Information System (INIS)

    Quinn, R.W.

    1983-01-01

    A thermonuclear bomb explosion over any city in the world would have a devastating effect on the population and environment. For those who survive, with or without injuries, life would become primitive with little or no uncontaminated food or water, and with inadequate housing, fuel, and medical care, resulting in a breakdown of family and interpersonal relationships. This theoretic study of the potential outcome of a thermonuclear bomb-burst over Nashville, Tennessee, discusses epidemiologically the wide range of medical and psychologic effects from the direct trauma of blast and fire, widespread epidemics of otherwise controlled disease, long-term chronic illness, genetic damage, and catastrophic environmental havoc

  16. Fiber-optic dipping liquid analyzer: theoretical and experimental study of light transmission

    International Nuclear Information System (INIS)

    Zhou Ai; Liu Zhihai; Yuan Libo

    2009-01-01

    A fiber-optic dipping liquid analyzer (FDLA) is developed for measuring liquid properties such as concentration, refractive index, surface tension, and viscosity. An important feature of the FDLA is that a liquid drop is introduced on the end face of a fiber probe, and the drop can be regarded as a planar-convex lens. The light transmitting path and receiving power are affected by the refractive index of the liquid drop. We present a theoretical and experimental analysis of the light transmission. A mathematical model of receiving power is established based on paraxial refraction imaging and fiber reflective intensity modulation methods. Sucrose-water solutions were tested with the FDLA. The experimental results agree well with the theoretical analysis.

  17. Solar pond conception - experimental and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Huseyin [Zonguldak Karaelmas Univ., Technical Education Faculty, Karabuk (Turkey); Halici, Fethi [Sakarya Univ., Mechanical Engineering Dept., Adapazari (Turkey); Binark, A. Korhan [Marmara Univ., Technical Education Faculty, Istanbul (Turkey)

    2000-07-01

    A one dimensional transient mathematical model for predicting the thermal performance of the salt gradient solar pond is developed and presented. In this paper, the natural solar ponds and different artificial solar pond systems found in the literature are introduced. Necessary modifications are made on the experimental stand located in Istanbul Technical University, the experimental stand is introduced and natural phenomena produced in the pond by the different solar pond variations under natural conditions are observed. In the theoretical work based on a one dimensional unsteady state heat conduction model with internal heat generation, the energy and mass balance equations for the upper convective zone, the non-convective zone and the lower convective zone, all of which form the solar pond, are written in terms of differential equations. These equations are solved analytically and numerically. The results obtained from the analysis are compared with the experimental results. The temperature and the concentration profiles are separately presented in the figures. (Author)

  18. Theoretical study of hyperfine fields due to S-P and transition impurities in gadolinium matrix

    International Nuclear Information System (INIS)

    Santos Leal, C.E. dos.

    1985-01-01

    This work presents a systematic theoretical study for the hyperfine field due to diluted s-p-and transition impurities in metallic gadolinium matrices. The peculiarities de a gadolinium matrix are shown, they are characterized by a semi-completed 4f-shell, which is far from (below) the energetic levels such as the type s-p and d-conduction bands. (author)

  19. Interaction between adrenaline and dibenzo-18-crown-6: Electrochemical, nuclear magnetic resonance, and theoretical study

    Science.gov (United States)

    Yu, Zhang-Yu; Liu, Tao; Wang, Xue-Liang

    2014-12-01

    The interaction between adrenaline (Ad) and dibenzo-18-crown-6 (DB18C6) was studied by cyclic voltammetry, nuclear magnetic resonance spectroscopy, and the theoretical calculations, respectively. The results show that DB18C6 will affect the electron transfer properties of Ad. DB18C6 can form stable supramolecular complexes with Ad through ion-dipole and hydrogen bond interactions.

  20. Theoretical studies on stability and feasibility of 0.34 THz EIK

    Science.gov (United States)

    Li, Shuang; Wang, Jianguo; Wang, Guangqiang; Wang, Dongyang

    2017-05-01

    The stability of the circuit and the tolerance during the manufacture process are theoretically studied in the design of 0.34 THz extended interaction klystron, which are helpful to increase the feasibility of the device. By using the small signal theory, the beam-loading conductance is studied to increase the efficiency of the beam-wave interaction. Combined with the study of start current for oscillation modes, the analysis of stability in multi-gap cavity is proposed, leading to the optimization of cavity. As a crucial factor affecting the ultimate performance of device, the inaccuracy during the fabrication process is researched. The acceptable tolerance is summarized through discussion of various geometrical dimensions' influences on cavity's characteristics. The study of power loss in the conductive wall is presented and the copper is believed to be adapted in making the device practicable with low attenuation. The physical design is simulated and verified by the particle-in-cell (PIC) method, and the results show that the output power of 142 W can be reached steadily at the frequency of 347.7 GHz, approaching the gain of 37.9 dB.

  1. Thermochemistry of sarcosine and sarcosine anhydride: Theoretical and experimental studies

    International Nuclear Information System (INIS)

    Amaral, Luísa M.P.F.; Santos, Ana Filipa L.O.M.; Ribeiro da Silva, Maria das Dores M.C.; Notario, Rafael

    2013-01-01

    Highlights: ► Study on the Energetics of the sarcosine and sarcosine anhydride. ► Experimental and computational thermochemistry of sarcosine and its anhydride. ► Ab initio calculations for two amino acid derivatives by G3(MP2)//B3LYP method. -- Abstract: The standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of sarcosine, −(388.0 ± 1.0) kJ · mol −1 , and sarcosine anhydride, −(334.5 ± 1.6) kJ · mol −1 , were calculated by combining, for each compound, the standard molar enthalpy of formation, in the crystalline phase, and the standard molar enthalpy of sublimation, derived from measurements of the standard massic energies of combustion by static bomb combustion calorimetry, and from measurements of vapour pressures by the Knudsen mass-loss effusion method, respectively. The standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs functions of sublimation, at T = 298.15 K, were also calculated. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared with the experimental ones

  2. Experimental and theoretical study of Co sorption in clay montmorillonites

    Science.gov (United States)

    Gil Rebaza, A. V.; Montes, M. L.; Taylor, M. A.; Errico, L. A.; Alonso, R. E.

    2018-03-01

    Montmorillonite (MMT) clays are 2:1 layered structures which in natural state may allocate different hydrated cations such as M-nH2O (M = Na, Ca, Fe, etc) in its interlayer space. Depending on the capability for ion sorption, these materials are interesting for environmental remediation. In this work we experimentally study the Co sorption in a natural Na-MMT using UV-visible spectrometry and XRD on semi-oriented samples, and then analyze the sorption ability of this clay by means of ab initio calculation performed on pristine MMT. The structural properties of Na-MMT and Co-adsorbed MMT, and the hyperfine parameters at different atomic sites were analyzed and compared with the experimental ones for the first, and for the case of the hyperfine parameters, presented for the first time for the last. The theoretical predictions based on total energy considerations confirm that Co incorporation replacing Na is energetically favorable. Also, the basal spacing d001 experimentally obtained is well reproduced.

  3. Theoretical study of indoline dyes for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Ham, Ho Wan; Kim, Young Sik

    2010-01-01

    Indoline dye sensitizers were designed and studied theoretically to increase molar extinction coefficients in the visible to near infrared region for solar-cell devices. To gain insight into dye sensitizers' structural, electronic, and optical properties, DFT/TDDFT calculations were performed on a series of dye sensitizers derived from the D149. The good agreement between the experimental and TDDFT calculated absorption spectra of the D149 sensitizer allowed us to provide a detailed assessment of the main spectral features of a series of dye sensitizers. Increase in the conjugation length resulted in a more red-shifted spectral response and less positive oxidation potential than that of the D149. The dye with the dimethylfluorene group showed stronger absorption bands due to a large dipole moment. The calculated dipoles for the dye series correlate well with the observed strong absorption bands of the electronic spectra. These results provided useful clues for the molecular engineering of efficient organic dye sensitizers.

  4. Theoretical and experimental study of a thruster discharging a weight

    Science.gov (United States)

    Michaels, Dan; Gany, Alon

    2014-06-01

    An innovative concept for a rocket type thruster that can be beneficial for spacecraft trajectory corrections and station keeping was investigated both experimentally and theoretically. It may also be useful for divert and attitude control systems (DACS). The thruster is based on a combustion chamber discharging a weight through an exhaust tube. Calculations with granular double-base propellant and a solid ejected weight reveal that a specific impulse based on the propellant mass of well above 400 s can be obtained. An experimental thruster was built in order to demonstrate the new idea and validate the model. The thruster impulse was measured both directly with a load cell and indirectly by using a pressure transducer and high speed photography of the weight as it exits the tube, with both ways producing very similar total impulse measurement. The good correspondence between the computations and the measured data validates the model as a useful tool for studying and designing such a thruster.

  5. Theoretical and experimental study of actinide complexes with monoamides and organophosphorus ligands in solution

    International Nuclear Information System (INIS)

    Ribokaite, Kristina

    2013-01-01

    Monoamides and organophosphate are of great interest for the nuclear fuel cycle. Such ligands can selectively extract actinides in liquid-liquid extraction processes. The structure of the extractant (its functional group and its alkyl substituents) has a predominant role in the selective separation of actinides. This thesis concerns the theoretical and experimental studies of model systems in the aim of better understanding of the effect on molecular structures of the complexes. Structures of actinides complexes formed with model ligands in simple media (water or methanol in the presence of nitrate ions) have been characterized. At first, the complexation of uranyl by monoamide and phosphine oxide was studied in water and methanol. Molecular Dynamics simulations and DFT calculations were used to quantify the stability of uranyl complexes with those ligands, and to determine their structural properties. The theoretical results were then compared with experimental results obtained by UV-visible, infrared, Raman and EXAFS on the same chemical systems. The results were used to highlight the greater stability of uranyl complexes with phosphine oxide and monoamides. Further spectroscopic measurements combined with molecular modeling were used to gain a better understanding of the coordination mode of nitrate ion around the uranyl in both water and methanol. Finally, DFT calculations were used to study the influence of the structure of the monoamide or organophosphorus ligand and their interaction with the actinides (IV, VI) including steric effects in the first coordination sphere. (author) [fr

  6. RECENT DEVELOPMENTS OF THE FINANCIAL REPORTING MODEL: THEORETICAL STUDIES IN REVIEW

    Directory of Open Access Journals (Sweden)

    Bonaci Carmen Giorgiana

    2011-07-01

    Full Text Available Our paper analyzes the manner in which the financial reporting model evolved towards fair value accounting. After a brief introduction into the context of financial reporting at international level, the analysis focuses on the accounting model of fair value. This is done by synthesizing main studies in accounting research literature that analyze fair value accounting through a theoretical approach. The analysis being developed relies on literature review methodology. The main purpose of the developed analysis is to synthesize main pros and cons as being documented through accounting research literature. Our findings underline both the advantages and shortcomings of fair value accounting and of the recent mixed attribute in nowadays financial reporting practices. The concluding remarks synthesize the obtained results and possible future developments of our analysis.

  7. On precipitation monitoring with theoretical statistical distributions

    Science.gov (United States)

    Cindrić, Ksenija; Juras, Josip; Pasarić, Zoran

    2018-04-01

    A common practice in meteorological drought monitoring is to transform the observed precipitation amounts to the standardised precipitation index (SPI). Though the gamma distribution is usually employed for this purpose, some other distribution may be used, particularly in regions where zero precipitation amounts are recorded frequently. In this study, two distributions are considered alongside with the gamma distribution: the compound Poisson exponential distribution (CPE) and the square root normal distribution (SRN). They are fitted to monthly precipitation amounts measured at 24 stations in Croatia in the 55-year-long period (1961-2015). At five stations, long-term series (1901-2015) are available and they have been used for a more detailed investigation. The accommodation of the theoretical distributions to empirical ones is tested by comparison of the corresponding empirical and theoretical ratios of the skewness and the coefficient of variation. Furthermore, following the common approach to precipitation monitoring (CLIMAT reports), the comparison of the empirical and theoretical quintiles in the two periods (1961-1990 and 1991-2015) is examined. The results from the present study reveal that it would be more appropriate to implement theoretical distributions in such climate reports, since they provide better evaluation for monitoring purposes than the current empirical distribution. Nevertheless, deciding on an optimal theoretical distribution for different climate regimes and for different time periods is not easy to accomplish. With regard to Croatian stations (covering different climate regimes), the CPE or SRN distribution could also be the right choice in the climatological practice, in addition to the gamma distribution.

  8. Theoretical studies of three triazole derivatives as corrosion inhibitors for mild steel in acidic medium

    International Nuclear Information System (INIS)

    Guo, Lei; Zhu, Shanhong; Zhang, Shengtao; He, Qiao; Li, Weihua

    2014-01-01

    Highlights: • Three triazole derivatives as corrosion inhibitors were theoretically investigated. • Quantum chemical calculations and Monte Carlo simulations were performed. • Quantitative structure activity relationship (QSAR) approach has been used. • Theoretical conclusions are validated by the consistency with experimental findings. - Abstract: Corrosion inhibitive performance of 4-chloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (CATM), 4-fluoro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (FATM), and 3,4-dichloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (DATM) during the acidic corrosion of mild steel surface was investigated using density functional theory (DFT). Quantum chemical parameters such as the highest occupied molecular orbital energy (E HOMO ), the lowest unoccupied molecular orbital energy (E LUMO ), energy gap (ΔE), Mulliken charges, hardness (ξ), dipole moment (μ), and the fraction of electrons transferred (ΔN), were calculated. Quantitative structure activity relationship (QSAR) approach has been used, and a composite index of above-mentioned descriptors was performed to characterize the inhibition performance of the studied molecules. Furthermore, Monte Carlo simulation studies were applied to search for the best configurational space of iron/triazole derivative system

  9. A theoretical study on the mechanism of electronic to vibrational energy transfer in Hg/3P/ + CO

    Science.gov (United States)

    Kato, S.; Jaffe, R. L.; Komornicki, A.; Morokuma, K.

    1983-01-01

    The mechanism of electronic-to-vibrational (E-V) energy transfer in Hg(3P) + CO collisions has been studied theoretically. The configuration interaction (CI) method was employed to calculate potential energy surfaces of the collision system. A simplified theoretical model, based on the reaction coordinate concept and the calculated potential energy characteristics, was used to discuss the mechanism of the singlet-triplet transition and the energy disposal in the collision. The results obtained were that: (a) the quenching process processed via a collision complex mechanism; and that (b) the triplet-singlet transition occurs near the collinear geometry. A model classical trajectory calculation gives a product CO vibrational distribution in good agreement with the experimental result.

  10. Action of Molecular Switches in GPCRs - Theoretical and Experimental Studies

    Science.gov (United States)

    Trzaskowski, B; Latek, D; Yuan, S; Ghoshdastider, U; Debinski, A; Filipek, S

    2012-01-01

    G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called “molecular switches” buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homo- and heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor

  11. A quantum theoretical study of reactions of methyldiazonium ion with DNA base pairs

    International Nuclear Information System (INIS)

    Shukla, P.K.; Ganapathy, Vinay; Mishra, P.C.

    2011-01-01

    Graphical abstract: Reactions of methyldiazonium ion at the different sites of the DNA bases in the Watson-Crick GC and AT base pairs were investigated employing density functional and second order Moller-Plesset (MP2) perturbation theories. Display Omitted Highlights: → Methylation of the DNA bases is important as it can cause mutation and cancer. → Methylation reactions of the GC and AT base pairs with CH 3 N 2 + were not studied earlier theoretically. → Experimental observations have been explained using theoretical methods. - Abstract: Methylation of the DNA bases in the Watson-Crick GC and AT base pairs by the methyldiazonium ion was investigated employing density functional and second order Moller-Plesset (MP2) perturbation theories. Methylation at the N3, N7 and O6 sites of guanine, N1, N3 and N7 sites of adenine, O2 and N3 sites of cytosine and the O2 and O4 sites of thymine were considered. The computed reactivities for methylation follow the order N7(guanine) > N3(adenine) > O6(guanine) which is in agreement with experiment. The base pairing in DNA is found to play a significant role with regard to reactivities of the different sites.

  12. Exploring occupational and behavioral risk factors for obesity in firefighters: A theoretical framework and study design

    OpenAIRE

    Choi, BK; Schnall, P; Dobson, M; Israel, L; Landsbergis, P; Galassetti, P; Pontello, A; Kojaku, S; Baker, D

    2011-01-01

    Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US). However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupatio...

  13. Theoretical study of the electromechanical efficiency of a loaded tubular dielectric elastomer actuator

    DEFF Research Database (Denmark)

    Rechenbach, Björn; Willatzen, Morten; Lassen, Benny

    2016-01-01

    The electromechanical efficiency of a loaded tubular dielectric elastomer actuator (DEA) is investigated theoretically. In previous studies, the external system, on which the DEA performs mechanical work, is implemented implicitly by prescribing the stroke of the DEA in a closed operation cycle....... Here, a more generic approach, modelling the external system by a frequency-dependent mechanical impedance which exerts a certain force on the DEA depending on its deformation, is chosen. It admits studying the dependence of the electromechanical efficiency of the DEA on the external system. A closed...... operation cycle is realized by exciting the DEA electrically by a sinusoidal voltage around a bias voltage. A detailed parametric study shows that the electromechanical efficiency is highly dependent on the frequency, amplitude, and bias of the excitation voltage and the mechanical impedance of the external...

  14. Theoretical and Numerical Study of Seismoelectric Logs for Logging While Drilling (LWD

    Directory of Open Access Journals (Sweden)

    Sun Xiang-Yang

    2017-01-01

    Full Text Available When the acoustic field propagates in the porous medium, the electromagnetic wave can be induced by the seismoelectric effects which can be used in the logging. This paper studies the seismoelectric wave field and deduces the formulations of the acoustic and electromagnetic field of the liquid in the well, and gives the acoustic and electromagnetic boundary conditions between the driller collar and the log liquid, when the driller collar is added. We also do the numerical simulation of the seismoelectric wave field excited by monopole source, study the velocity dispersion characteristics of the acoustic and electromagnetic field, and investigate the detective depth of the seismoelectric logs. Through the simulation we know the seismoelectric logs can avoid the interference of drill collar wave. This paper also provides theoretical guidance for the design of receiving antenna.

  15. In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies.

    Science.gov (United States)

    Abo Dena, Ahmed S; Abdel Gaber, Sara A

    2017-06-15

    Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1 HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies

    Science.gov (United States)

    Abo Dena, Ahmed S.; Abdel Gaber, Sara A.

    2017-06-01

    Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV.

  17. Isolation, spectroscopic characterization, X-ray, theoretical studies as well as in vitro cytotoxicity of Samarcandin

    Czech Academy of Sciences Publication Activity Database

    Ghoran, S.H.; Atabaki, V.; Babaei, E.; Olfatkhah, S.R.; Dušek, Michal; Eigner, Václav; Soltani, A.; Khalaji, A.D.

    2016-01-01

    Roč. 66, Jun (2016), s. 27-32 ISSN 0045-2068 R&D Projects: GA ČR GA15-12653S; GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : cytotoxicity * NMR * sesquiterpene coumarin * theoretical study * TD-DFT * X-ray Subject RIV: CC - Organic Chemistry Impact factor: 3.231, year: 2016

  18. Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

    Science.gov (United States)

    Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

    2008-09-01

    The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

  19. A theoretical study of the fast-neutron attenuation in Ghanaian serpentine shields

    International Nuclear Information System (INIS)

    Akaho, E.H.K.; Anim-Sampong, S.

    1994-01-01

    Theoretical calculations were done to determine the suitability of local serpentine rocks for shielding fast neutrons. A coupled neutron-gamma library of 25 energy groups, IRAN3.LIB developed for ANISN/PC was used to generate nuclear data for the tested shields. Calculations were carried out assuming a P 3 scattering order for spherical geometry with S 6 angular quadrature. From the trends of attenuation and computer factors such as relaxation length and transmission there is the indication that the shielding properties of the local shields are better than the foreign serpentine shields used in this study. They are slightly inferior to ordinary concrete employed in shielding power reactors. (author). 9 refs.; 5 tabs.; 5 figs

  20. Theoretical study of the magnetic behavior of hexanuclear Cu(II) and Ni(II) polysiloxanolato complexes.

    Science.gov (United States)

    Ruiz, Eliseo; Cano, Joan; Alvarez, Santiago; Caneschi, Andrea; Gatteschi, Dante

    2003-06-04

    A theoretical density functional study of the exchange coupling in hexanuclear polysiloxanolato-bridged complexes of Cu(II) and Ni(II) is presented. By calculating the energies of three different spin configurations, we can obtain estimates of the first-, second-, and third-neighbor exchange coupling constants. The study has been carried out for the complete structures of the Cu pristine cluster and of the chloroenclathrated Ni complex as well as for the hypotethical pristine Ni compound and for magnetically dinuclear analogues M(2)Zn(4) (M = Cu, Ni).

  1. Experimental and theoretical studies of the effects of nonuniformities in equilibrium MHD generators

    International Nuclear Information System (INIS)

    Rosenbaum, M.; Shamma, S.E.; Louis, J.F.

    1980-01-01

    An experimental study of the effects of thermal and velocity nonuniformities is performed in an equilibrium plasma for a range of Hall parameters. An electrodeless MHD disk generator with radial flow is chosen as the ideal geometry for these experiments. By introducing equally spaced cold blades in the flow, it is possible to create well defined two-dimensional wake nonuniformities with strong variations of the plasma properties in the direction normal to the magnetic field and the flow. This type of nonuniformity is predicted to provide the strongest reduction of Hall coefficient and effective conductivity for high values of Hall parameter. This degradation is controlled by both the level of nonuniformities and the value of the ideal Hall parameter. The former is dependent upon the number of blades (root mean square deviation of the conductivity), and the latter is dependent upon the values of the magnetic field intensities. The results provide basic quantitative information about the effects of conductivity and velocity nonuniformities on the performance of equilibrium MHD generators over a wide range of Hall coefficients, between 2 and 7. Reduction formulae are established between the effective and ideal Hall parameters for different levels of nonuniformities intensities. Theoretical predictions are derived from a detailed two-dimensional electrodynamic analysis and a simplified engineering model based on a generalization of Rosa's layer model. These experiments validate the analytical studies and support the use of the theoretical layer models in describing the effect of boundary layers on the performance of linear generators

  2. THEORETICAL AND METHODOLOGICAL APPROACHES TO THE STUDY OF THE IMPACT OF INFORMATION TECHNOLOGY ON SOCIAL CONNECTIONS AMONG YOUTH

    Directory of Open Access Journals (Sweden)

    Sofia Alexandrovna Zverkova

    2015-11-01

    Full Text Available The urgency is due to the virtualization of communication in modern society, especially among young people, affecting social relations and social support services. Stressed the need for a more in-depth study of network virtualization of social relations of society, due to the ambiguous consequences of this phenomenon among the youth.Purpose. Analyze classic and contemporary theoretical and methodological approaches to the study of social ties and social support in terms of technological progress.Results. The article presents a sociological analysis of theoretical and methodological approaches to the study of problems of interaction and social support among youth through strong and weak social ties in cyberspace and in the real world.Practical implications. The analysis gives the opportunity for a wide range of examining social relations in various fields of sociology, such as sociology of youth, sociology of communications.

  3. Theoretical Foundations of Active Learning

    Science.gov (United States)

    2009-05-01

    I study the informational complexity of active learning in a statistical learning theory framework. Specifically, I derive bounds on the rates of...convergence achievable by active learning , under various noise models and under general conditions on the hypothesis class. I also study the theoretical...advantages of active learning over passive learning, and develop procedures for transforming passive learning algorithms into active learning algorithms

  4. Experimental and theoretical study of the operation of longitudinal sidewalls in reinforced concrete superstructures

    Science.gov (United States)

    Bokarev, Sergey; Efimov, Stefan

    2017-11-01

    In the present article, we report results of a laboratory experimental study of reinforced-concrete superstructure fragments with extended longitudinal boxing sidewalls. The study included laboratory tests and numerical experiments performed using a finite element model of fragments generated in specialized simulation software. The distribution of horizontal pressures over the height of longitudinal boxing sidewalls, the dependence of the bending moment in the root section of the sidewalls on the ballast-bed thickness under sleepers, and some other characteristics were examined. The results of the experimental and theoretical study have shown a good convergence of obtained data to each other and to the data obtained by an improved engineering calculation procedure proposed by the present authors.

  5. Experimental and theoretical studies of the thermal behavior of titanium dioxide-SnO2 based composites.

    Science.gov (United States)

    Voga, G P; Coelho, M G; de Lima, G M; Belchior, J C

    2011-04-07

    In this paper we report experimental and theoretical studies concerning the thermal behavior of some organotin-Ti(IV) oxides employed as precursors for TiO(2)/SnO(2) semiconducting based composites, with photocatalytic properties. The organotin-TiO(2) supported materials were obtained by chemical reactions of SnBu(3)Cl (Bu = butyl), TiCl(4) with NH(4)OH in ethanol, in order to impregnate organotin oxide in a TiO(2) matrix. A theoretical model was developed to support experimental procedures. The kinetics parameters: frequency factor (A), activation energy, and reaction order (n) can be estimated through artificial intelligence methods. Genetic algorithm, fuzzy logic, and Petri neural nets were used in order to determine the kinetic parameters as a function of temperature. With this in mind, three precursors were prepared in order to obtain composites with Sn/TiO(2) ratios of 0% (1), 15% (2), and 30% (3) in weight, respectively. The thermal behavior of products (1-3) was studied by thermogravimetric experiments in oxygen.

  6. Computability, complexity, and languages fundamentals of theoretical computer science

    CERN Document Server

    Davis, Martin D; Rheinboldt, Werner

    1983-01-01

    Computability, Complexity, and Languages: Fundamentals of Theoretical Computer Science provides an introduction to the various aspects of theoretical computer science. Theoretical computer science is the mathematical study of models of computation. This text is composed of five parts encompassing 17 chapters, and begins with an introduction to the use of proofs in mathematics and the development of computability theory in the context of an extremely simple abstract programming language. The succeeding parts demonstrate the performance of abstract programming language using a macro expa

  7. Theoretical studies on the alpha α decay half-lives of hyper and normal isotopes of Po

    Science.gov (United States)

    Santhosh, K. P.; Nithya, C.

    2018-03-01

    The α decay half-lives of hyper and normal isotopes of Po nuclei are studied in the present work. The inclusion of Λ - N interaction changes the half-life for α decay. The theoretical predictions on the α decay half-lives of normal Po isotopes are compared with experimental results and are seen to be matching well with each other. The neutron shell closure at N = 126 is found to be the same for both normal and hypernuclei. The Geiger-Nuttal (G-N) law for α decay is unaltered in the case of hypernuclei. The hypernuclei will decay into normal nuclei by mesonic or non-mesonic decay modes. Since the half-lives of normal Po nuclei are well within the experimental limits, our theoretical results suggest experimental verification of the α emission from hyper Po nuclei in a cascade process.

  8. A theoretical study of the spheroidal droplet evaporation in forced convection

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jie, E-mail: leejay1986@163.com; Zhang, Jian

    2014-11-07

    In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time. - Highlights: • Fully algebraic solutions for the spheroidal droplet evaporation rate is obtained. • We examine the effect of aspect ratio on the droplet evaporation. • We propose a calculation method of Nusselt number for spheroidal droplet.

  9. A theoretical study of the spheroidal droplet evaporation in forced convection

    International Nuclear Information System (INIS)

    Li, Jie; Zhang, Jian

    2014-01-01

    In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time. - Highlights: • Fully algebraic solutions for the spheroidal droplet evaporation rate is obtained. • We examine the effect of aspect ratio on the droplet evaporation. • We propose a calculation method of Nusselt number for spheroidal droplet

  10. Studies of Credit and Equity Markets with Concepts of Theoretical Physics

    CERN Document Server

    Münnix, Michael C

    2011-01-01

    Financial markets are becoming increasingly complex. The financial crisis of 2008 to 2009 has demonstrated that an improved understanding of the mechanisms embedded in the market is a key requirement for the estimation of financial risk. Recently, concepts of theoretical physics, in particular concepts of complex systems, have proven to be very useful in this regard. Michael C. Münnix analyses the statistical dependencies in financial markets and develops mathematical models using concepts and methods from physics. The author focuses on aspects that played a key role in the emergence of the recent financial crisis: estimation of credit risk, dynamics of statistical dependencies, and correlations on small time-scales. He visualizes the findings for various large-scale empirical studies of market data. The results give novel insights into the mechanisms of financial markets and allow conclusions on how to reduce financial risk significantly.

  11. An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

    Energy Technology Data Exchange (ETDEWEB)

    Svelle, Stian

    2004-07-01

    The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the

  12. Theoretical study (ab initio and DFT methods on acidic dissociation constant of xylenol orange in aqueous solution

    Directory of Open Access Journals (Sweden)

    F. Kiani

    2017-07-01

    Full Text Available Analytical measurement of materials requires exact knowledge of their acid dissociation constant (pKa values. In recent years, quantum mechanical calculations have been extensively used to study of acidities in the aqueous solutions and the results were compared with the experimental values. In this study, a theoretical study was carried out on xylenol orange (in water solution by ab initio method. We calculated the pKa values of xylenol orange in water, using high-level ab initio (PM3, DFT (HF, B3LYP/6-31+G(d and SCRF methods. The experimental determination of these values (pKa,s is a challenge because xylenol orange has a low solubility in water. We considered several ionization reactions and equilibriums in water that constitute the indispensable theoretical basis to calculate the pKa values of xylenol orange. The results show that the calculated pKa values have a comparable agreement with the experimentally determined pKa values. Therefore, this method can be used to predict such properties for indicators, drugs and other important molecules.

  13. Experimental and theoretical study on complexation of Li+ with lithium ionophore VIII

    Czech Academy of Sciences Publication Activity Database

    Makrlík, E.; Novák, V.; Vaňura, P.; Bouř, Petr

    2013-01-01

    Roč. 144, č. 11 (2013), s. 1607-1611 ISSN 0026-9247 Institutional support: RVO:61388963 Keywords : ionophores * macrocycles * complexation * DFT calculations * structures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.347, year: 2013

  14. Experimental and theoretical study of plasma-water interaction in electrothermal guns

    International Nuclear Information System (INIS)

    Arensburg, Alex.

    1993-05-01

    This thesis comprises an experimental and theoretical study of the plasma- jet-water interaction in electrothermal guns. In the present work the plasma jet was produced by high current pulsed discharge in a plasma injector consisting of polyethylene capillary, closed at one end by a metallic anode and supported at the other end with a hollow cathode. A thin aluminium fuse placed inside the capillary and connecting both electrodes, provided an initial conducting element. A pulse forming network delivering a high current pulse through the fuse, exploded it and produced an aluminium plasma. Subsequently, ablation of the capillary wall begun as a result of its exposure to radiation from the fuse plasma. The ablation products were heated by the pulse current until ionized, replacing the fuse plasma by a polyethylene plasma thus sustaining the ablation process. The experimental investigation reported here used x-ray shadowgraphy to observe the plasma-working fluid interaction process. The working fluid was an aqueous solution of 92% water and 8% lead acetate gelatinized with agar. The penetration of the plasma jet into the working fluid was exposed on films at successive time intervals by means of x-ray shadowgraphy. When the water interacts with the plasma it also ablated. This ablation rate was estimated from energy conservation considerations. Peak pressures up to 3.5*10 8 Pa were measured during the process. At such pressure water does not undergo phase transformation when heated. Thus the mass density at the plasma water interface should be regarded as a continuous function of temperature. The determination of the temperature profile at the interface between the capillary plasma and the water requires the solution of the heat transfer and radiative transfer equations under ablation conditions. This constituted the main theoretical part of the present work. 36 refs., 4 tabs., 29 figs

  15. An experimental and theoretical study of decentralized gas fired liquid heating

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Rolf

    1996-12-01

    The effects on the energy situation in industry when gas fired liquid heaters replace steam have been determined by energy surveys performed in a brewery and a slaughterhouse, measurements of the performance and emissions from liquid heaters installed in these industries, and theoretical analyses of the potential energy. The theoretical study in the first part of the project provides information that allows assessment of the effects on the energy situation, of a part or complete conversion to decentralized heating, under the conditions prevailing in the industries concerned. The second part of the project focused on increasing the liquid heater efficiency and reducing emissions of carbon monoxide and hydrocarbons. Heat transfer and pressure drop for a corrugated tube was investigated experimentally. Empirical correlations for heat transfer and pressure drop for a corrugated tube were developed. These correlations were used in the design model that was developed within this project. The design model was validated against experimental data and data from an industrial application, where a section of the smooth heat exchanger tube was replaced with a corrugated tube. The results show that the design model predicts the outlet flue gas temperature and the heater efficiency quite accurately. The wall temperature at the first corrugation is also predicted with reasonable accuracy. These results make it possible to calculate the location where a corrugated tube can be inserted without causing subcooled boiling or severe fouling. It is shown that emissions of carbon monoxide and hydrocarbons can be held at low levels, even when conventional industrial burners are used. The use of nozzles that produce long soft flames increase the risk for large emissions of hydrocarbons and carbon monoxide. 125 refs, 89 figs, 16 tabs

  16. Present status of the theoretical relativistic plasma SHF electronics

    International Nuclear Information System (INIS)

    Kuzelev, M.V.; Rukhadze, A.A.

    2000-01-01

    Paper presents a review of theoretical investigations into powerful sources of SHF waves grounded on the forced emission of relativistic electron beams in plasma wave guides and resonator. Emission sources operating under amplification of a certain inlet signal and under generation mode were studied. Two mechanisms of forced emission: resonance Cherenkov radiation of relativistic electron beams in plasma and nonresonance Pierce emission resulting from evolution of high-frequency Pierce instability, were studied. Paper discusses theoretical problems only, all evaluations and calculations are made for the parameters of the exact experiments, the theoretical results are compared with the available experimental data. Factors affecting formation of spectrum of waves excited by relativistic electron beam in plasma systems are discussed [ru

  17. Comparative antioxidant status in freshwater fish Carassius auratus exposed to six current-use brominated flame retardants: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mingbao; Qu, Ruijuan; Wang, Chao; Wang, Liansheng; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-15

    Highlights: •A combined experimental and theoretical approach was used for risk assessments of six BFRs in fish. •Oxidative stress biomarkers were measured for toxicity identification. •Toxicity order was proposed via the integrated biomarker response. •Theoretical calculations were performed to analyze the BFRs toxicity. -- Abstract: Decabromodiphenyl ether (BDE-209) and several non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), such as tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB) and pentabromotoluene (PBT), are persistent halogenated contaminants ubiquitously detected in aquatic systems. However, data on comparative toxicological effects of these BFRs are lacking for fish. In this study, a combined experimental and theoretical approach was used to compare and analyze the effects of these BFRs on biochemical biomarkers in liver of Carassius auratus injected intraperitoneally with different doses (10 and 100 mg/kg) for 7, 14 and 30 days. Oxidative stress was evoked evidently for the prolonged exposure, represented by the significantly altered indices (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and malondialdehyde). The integrated biomarker response (IBR) index ranked biotoxicity as: PBT > HBB > HBCD > TBBPA > BDE-209 > DBDPE. Quantum chemical calculations (electronic parameters, frontier molecular orbitals, and Wiberg bond order) were performed for theoretical analysis. Notably, some descriptors were correlated with the toxicity order, probably implying the existence of a potential structure–activity relationship when more BFRs were included. Besides, theoretical calculations also provided some valuable information regarding the molecular characteristics and metabolic pathways of these current-use BFRs, which may facilitate the understanding on their environmental behavior and fate. Overall, this study adopted a combined

  18. Damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses: theoretical and experimental study

    International Nuclear Information System (INIS)

    Meng, Qinglong; Zhang, Bin; Zhong, Sencheng; Zhu, Liguo

    2016-01-01

    The damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses has been studied theoretically and experimentally. Firstly, the model for the damage threshold prediction of crystal materials based on the improved rate equation has been proposed. Then, the experimental measure method of the damage threshold of crystal materials has been given in detail. On the basis, the variation of the damage threshold of lithium niobate crystal with the pulse duration has also been analyzed quantitatively. Finally, the damage threshold of lithium niobate crystal under multiple laser pulses has been measured and compared to the theoretical results. The results show that the transmittance of lithium niobate crystal is almost a constant when the laser pulse fluence is relative low, whereas it decreases linearly with the increase in the laser pulse fluence below the damage threshold. The damage threshold of lithium niobate crystal increases with the increase in the duration of the femtosecond laser pulse. And the damage threshold of lithium niobate crystal under multiple laser pulses is obviously lower than that irradiated by a single laser pulse. The theoretical data fall in good agreement with the experimental results. (orig.)

  19. A study of insider threat in nuclear security analysis using game theoretic modeling

    International Nuclear Information System (INIS)

    Kim, Kyo-Nam; Yim, Man-Sung; Schneider, Erich

    2017-01-01

    Highlights: • Implications of an insider threat in nuclear security were quantitatively analyzed. • The analysis was based on of a hypothetical nuclear facility and using game theoretic approach. • Through a sensitivity analysis, vulnerable paths and important parameters were identified. • The methodology can be utilized to prioritize the implementation of PPS improvements in a facility. - Abstract: An Insider poses a greater threat to the security system of a nuclear power plant (NPP) because of their ability to take advantage of their access rights and knowledge of a facility, to bypass dedicated security measures. If an insider colludes with an external terrorist group, this poses a key threat to the safety-security interface. However, despite the importance of the insider threat, few studies have been conducted to quantitatively analyze an insider threat. This research examines the quantitative framework for investigating the implications of insider threat, taking a novel approach. Conventional tools assessing the security threats to nuclear facilities focus on a limited number of attack pathways. These are defined by the modeler and are based on simple probabilistic calculations. They do not capture the adversary’s intentions nor do they account for their response and adaptation to defensive investments. As an alternative way of performing physical protection analysis, this research explores the use of game theoretic modeling of Physical Protection Systems (PPS) analysis by incorporating the implications of an insider threat, to address the issues of intentionality and interactions. The game theoretic approach has the advantage of modeling an intelligent adversary and insider who has an intention to do harm and complete knowledge of the facility. Through a quantitative assessment and sensitivity analysis, vulnerable but important parameters in this model were identified. This made it possible to determine which insider threat is more important. The

  20. Theoretical and experimental high energy physics

    International Nuclear Information System (INIS)

    Walsh, T.; Ruddick, K.

    1990-01-01

    This report discusses the following topics: The Soudan enterprise; study of strange quarks at Fermilab; direct photons at Fermilab; the Brookhaven programs; AMY and CLEO: studies of e + e - annihilations; cosmic ray studies with the DO muon chamber; progress report on HEP computer upgrade; muon triggering and reconstruction at SSC; and, theoretical high energy physics

  1. A Social-Cognitive Theoretical Framework for Examining Music Teacher Identity

    Science.gov (United States)

    McClellan, Edward

    2017-01-01

    The purpose of the study was to examine a diverse range of research literature to provide a social-cognitive theoretical framework as a foundation for definition of identity construction in the music teacher education program. The review of literature may reveal a theoretical framework based around tenets of commonly studied constructs in the…

  2. A theoretical study of spectroscopy and metastability of the CN2+ dication

    Czech Academy of Sciences Publication Activity Database

    Fišer, J.; Polák, Rudolf

    2012-01-01

    Roč. 392, č. 1 (2012), s. 55-62 ISSN 0301-0104 Institutional research plan: CEZ:AV0Z40400503 Keywords : CN * CN+ * CN2+ Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.957, year: 2012

  3. Hydrodynamic Instability and Dynamic Burnout in Natural Circulation Two-Phase Flow. An Experimental and Theoretical Study

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Kurt M; Jahnberg, S; Haga, I; Hansson, P T; Mathisen, R P

    1964-09-15

    A theoretical model for predicting the threshold of instability for two phase flow in a natural circulation loop is presented. The model calculates the flow transient caused by a step disturbance of the heat input, and is based upon the conservation laws of mass, momentum and energy in one dimensional form. Empirical correlations are used in the model for estimating the void fractions and the two-phase flow pressure drops. The equations are solved numerically in a finite difference approximation coded for a digital computer. An experimental study of the hydrodynamic instability and dynamic burnout in two-phase flow has been performed in a natural circulation loop in the pressure range from 10 to 70 atg. The test sections were round ducts of 20, 30 and 36 mm inner diameter and 4890 mm heated length. The experimental results showed that within the ranges tested, the stability of the flow increases with increasing pressure and increasing throttling before the test section, but decreases with increasing Inlet subcooling and increasing throttling after the test section. Comparing the natural circulation burnout steam qualities with corresponding forced circulation data shoved that the former data were low by a factor up to 2.5. However, by applying inlet throttling of the flow the burnout values approached and finally coincided with the forced circulation data. The present experimental results as well as data available from other sources have been compared with the stability thresholds obtained with the theoretical model. The comparisons included circular, annular and rod cluster geometries, and the agreement between the experimental and theoretical stability limits was good. Finally the application of the experimental and theoretical results on the assessment of boiling heavy water reactor design is discussed.

  4. Hydrodynamic Instability and Dynamic Burnout in Natural Circulation Two-Phase Flow. An Experimental and Theoretical Study

    International Nuclear Information System (INIS)

    Becker, Kurt M.; Jahnberg, S.; Haga, I.; Hansson, P.T.; Mathisen, R.P.

    1964-09-01

    A theoretical model for predicting the threshold of instability for two phase flow in a natural circulation loop is presented. The model calculates the flow transient caused by a step disturbance of the heat input, and is based upon the conservation laws of mass, momentum and energy in one dimensional form. Empirical correlations are used in the model for estimating the void fractions and the two-phase flow pressure drops. The equations are solved numerically in a finite difference approximation coded for a digital computer. An experimental study of the hydrodynamic instability and dynamic burnout in two-phase flow has been performed in a natural circulation loop in the pressure range from 10 to 70 atg. The test sections were round ducts of 20, 30 and 36 mm inner diameter and 4890 mm heated length. The experimental results showed that within the ranges tested, the stability of the flow increases with increasing pressure and increasing throttling before the test section, but decreases with increasing Inlet subcooling and increasing throttling after the test section. Comparing the natural circulation burnout steam qualities with corresponding forced circulation data shoved that the former data were low by a factor up to 2.5. However, by applying inlet throttling of the flow the burnout values approached and finally coincided with the forced circulation data. The present experimental results as well as data available from other sources have been compared with the stability thresholds obtained with the theoretical model. The comparisons included circular, annular and rod cluster geometries, and the agreement between the experimental and theoretical stability limits was good. Finally the application of the experimental and theoretical results on the assessment of boiling heavy water reactor design is discussed

  5. Resistance and Renewal in Theoretical Psychology

    DEFF Research Database (Denmark)

    psychology, resistance and renewal, form the overall theme for a selection of theoretical papers that is framed — in this iteration of the International Society for Theoretical Psychology's (ISTP) proceedings — by reflections on the 30 year history of the ISTP as well as by considerations of the future....... The diversity and creativity of the work undertaken within theoretical psychology is further exemplified by papers on the history of the ISTP and theoretical psychology, a new paradigm for functional disorders, experimental introspection and techniques of self, the performativity of psychological science......Theoretical psychologists continue to challenge psychology, related disciplines and the work of other theoretical psychologists through a wide variety of activities that include conceptual clarification and creative theorizing. In many cases, these activities are experienced by the relevant...

  6. A configurational and conformational study of aframodial and its diasteriomers via experimental and theoretical VA and VCD spectroscopies

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Gale, J.D.; Lassen, Peter Rygaard

    2008-01-01

    In this work we present the experimental and theoretical vibrational absorption (VA) and the theoretical vibrational circular dichroism (VCD) spectra for aframodial. In addition, we present the theoretical VA and VCD spectra for the diasteriomers of aframodial. Aframodial has four chiral centers ...

  7. Theoretical progress in studying the characteristic x-ray emission from heavy few-electron ions

    International Nuclear Information System (INIS)

    Surzhykov, Andrey; Stohlker, Thomas; Fritzsche, Stephan; Kabachnik, Nikolai M

    2009-01-01

    Recent theoretical progress in the study of the x-ray characteristic emission from highly-charged, few-electron ions is reviewed. These investigations show that the bound-state radiative transitions in high-Z ions provide a unique tool for better understanding the interplay between the structural and dynamical properties of heavy ions. In order to illustrate such an interplay, detailed calculations are presented for the K α1 decay of the helium-like uranium ions U 90+ following radiative electron capture, Coulomb excitation and dielectronic recombination processes.

  8. Experimental and theoretical study of CO adsorption on the surface of single phase hexagonally plate ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Amin; Firooz, Azam Anaraki [Chemistry Department, Faculty of Sciences, Shahid Rajaee Teacher Training University, PO Box 16785-163, Tehran (Iran, Islamic Republic of); Beheshtian, Javad, E-mail: j.beheshtian@srttu.edu [Chemistry Department, Faculty of Sciences, Shahid Rajaee Teacher Training University, PO Box 16785-163, Tehran (Iran, Islamic Republic of); Khodadadi, Abbas Ali [Oil and Gas Processing Center of Excellence, School of Chemical Engineering, University of Tehran, 11155-4563 Tehran (Iran, Islamic Republic of)

    2014-10-01

    Highlights: • Hexagonally plate ZnO microstructure was synthesized by a simple hydrothermal method. • HRTEM images indicated a single crystal with a [0 0 1] direction growth. • DFT calculations were performed to reveal structure and electronic properties of ZnO. • The CO sensor response was close to obtained theoretical results. - Abstract: A simple low temperature hydrothermal method has been investigated for synthesis of single phase hexagonally plate ZnO microstructure. The synthesized ZnO was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) photoluminescence spectrum (PL) and ultraviolet and visible absorption spectroscopy (UV–vis) to investigate the surface morphology, crystallographic phase, optical properties and used as a sensor for detection of CO gas molecules. It was observed that the ZnO microstructures were uniform size, single phase and symmetrical, with a hexagonal shape and height of ∼250 nm. The optical band gap value of this sample was calculated to be about 3.22 eV, which show a red shift with theoretical method. High-resolution TEM images indicate that all the microstructures are single crystals with a [0 0 1] direction growth. We studied the gas response of this sample to 500 ppm CO over a temperature range of 200–400 °C and compared with theoretical results. Density functional theory (DFT) calculations were employed to investigate the structure and electronic properties of ZnO with simulating the adsorption process of CO gas on the ZnO (1 0 1) surface. The theoretical results were in good agreement with experimental results.

  9. Strategic Step for Environmental Rescue: A Theoretical Legal Studies

    Directory of Open Access Journals (Sweden)

    Bambang Sutrisno

    2014-01-01

    Full Text Available Indonesia is among the developing countries that are struggling to develop in the field of industrial development. The logical consequence of any development process, especially industrial development is the emergence of associated impacts that greatly affect the durability and sustainability of the environment. Developing the equitable industry in order to create public welfare is important. However, maintaining the security and preservation of the environment is also very important, because it is only with the availability of a good environment and healthy living that human beings can perform daily living. The availability of good and healthy environment is the constitutional responsibility of the government, as well as part of the human rights of all citizens which must be given by the State. Efforts to create a good environment and healthy living will be effective if controlled by State government and institutions who understand the objective conditions on the ground. In this regard, the granting of the authority on environmental control to regional government autonomously is the right, very smart policy choice. How To Cite: Sutrisno, B. (2016. Strategic Step for Environmental Rescue: A Theoretical Legal Studies. Rechtsidee, 1(1, 27-58. doi:http://dx.doi.org/10.21070/jihr.v1i1.98

  10. Theoretical Biology and Medical Modelling: ensuring continued growth and future leadership.

    Science.gov (United States)

    Nishiura, Hiroshi; Rietman, Edward A; Wu, Rongling

    2013-07-11

    Theoretical biology encompasses a broad range of biological disciplines ranging from mathematical biology and biomathematics to philosophy of biology. Adopting a broad definition of "biology", Theoretical Biology and Medical Modelling, an open access journal, considers original research studies that focus on theoretical ideas and models associated with developments in biology and medicine.

  11. Fragmentation dynamics of ionized neon trimer inside helium nanodroplets: a theoretical study.

    Science.gov (United States)

    Bonhommeau, David; Viel, Alexandra; Halberstadt, Nadine

    2004-06-22

    We report a theoretical study of the fragmentation dynamics of Ne(3) (+) inside helium nanodroplets, following vertical ionization of the neutral neon trimer. The motion of the neon atoms is treated classically, while transitions between the electronic states of the ionic cluster are treated quantum mechanically. A diatomics-in-molecules description of the potential energy surfaces is used, in a minimal basis set consisting of three effective p orbitals on each neon atom for the missing electron. The helium environment is modeled by a friction force acting on the neon atoms when their speed exceeds the Landau velocity. A reasonable range of values for the corresponding friction coefficient is obtained by comparison with existing experimental measurements. (c) 2004 American Institute of Physics.

  12. Experimental and theoretical study on natural circulation capacity under rolling motion condition

    International Nuclear Information System (INIS)

    Tan Sichao; Gao Puzhen

    2007-01-01

    Effect of rolling motion on natural circulation capacity was studied experimentally and theoretically. Experiments were conducted under the conditions of rolling and unrolling motions. The experimental results show that natural circulation capacity decreases under rolling motion condition. A mathematic model was developed to calculate the natural circulation capacity under rolling motion condition, considering the characteristics of natural circulation, the model was modified. The calculated results agree with experimental data well. Effect of rolling motion on natural circulation was analyzed through calculation and the following conclusions were obtained: (1) The increase of flow resistance coefficient is the main reason that the natural circulation capacity decreases under rolling motion condition; (2) Non-uniform distribution of fluid mass in the pipe has also influence on natural circulation capacity. (author)

  13. Theoretical study for aerial image intensity in resist in high numerical aperture projection optics and experimental verification with one-dimensional patterns

    Science.gov (United States)

    Shibuya, Masato; Takada, Akira; Nakashima, Toshiharu

    2016-04-01

    In optical lithography, high-performance exposure tools are indispensable to obtain not only fine patterns but also preciseness in pattern width. Since an accurate theoretical method is necessary to predict these values, some pioneer and valuable studies have been proposed. However, there might be some ambiguity or lack of consensus regarding the treatment of diffraction by object, incoming inclination factor onto image plane in scalar imaging theory, and paradoxical phenomenon of the inclined entrance plane wave onto image in vector imaging theory. We have reconsidered imaging theory in detail and also phenomenologically resolved the paradox. By comparing theoretical aerial image intensity with experimental pattern width for one-dimensional pattern, we have validated our theoretical consideration.

  14. Theoretical Approaches to Lignin Chemistry

    OpenAIRE

    Shevchenko, Sergey M.

    1994-01-01

    A critical review is presented of the applications of theoretical methods to the studies of the structure and chemical reactivity of lignin, including simulation of macromolecular properties, conformational calculations, quantum chemical analyses of electronic structure, spectra and chemical reactivity. Modern concepts of spatial organization and chemical reactivity of lignins are discussed.

  15. Theoretical and Computational Studies of Rare Earth Substitutes: A Test-bed for Accelerated Materials Development

    Energy Technology Data Exchange (ETDEWEB)

    Benedict, Lorin X. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    Hard permanent magnets in wide use typically involve expensive Rare Earth elements. In this effort, we investigated candidate permanent magnet materials which contain no Rare Earths, while simultaneously exploring improvements in theoretical methodology which enable the better prediction of magnetic properties relevant for the future design and optimization of permanent magnets. This included a detailed study of magnetocrystalline anisotropy energies, and the use of advanced simulation tools to better describe magnetic properties at elevated temperatures.

  16. Crystal growth, characterization and theoretical studies of 4-aminopyridinium picrate

    Science.gov (United States)

    Aditya Prasad, A.; Muthu, K.; Rajasekar, M.; Meenatchi, V.; Meenakshisundaram, S. P.

    2015-01-01

    Single crystals of 4-aminopyridinium picrate (APP) were grown by slow evaporation of a mixed solvent system methanol-acetone (1:1, v/v) containing equimolar quantities of 4-aminopyridine and picric acid. Structure is elucidated by single crystal XRD analysis and the crystal belongs to monoclinic system with four molecules in the unit cell (space group P21/c) and the cell parameter values are, a = 8.513 Å (±0.015), b = 11.33 Å (±0.02), c = 14.33 Å (±0.03) and β = 104.15° (±0.019), V = 1340 A3 (±6) with refined R factors R1 = 0.0053 and wR2 = 0.0126. The electron density mapping is interpreted to find coordinates for each atom in the crystallized molecules. The various functional groups present in the molecule are confirmed by FT-IR analysis. UV-visible spectral analysis was used to determine the band gap energy of 4-aminopyridinium picrate. Powder X-ray diffraction pattern reveals the crystallinity of the as-grown crystal and it closely resembles the simulated XRD from the single crystal XRD analysis. Scanning electron microscopy reveals the surface morphology of the grown crystal. Optimized geometry is derived by Hartree-Fock theory calculations and the first-order molecular hyperpolarizability (β), theoretically calculated bond length, bond angles and excited state energy from theoretical UV-vis spectrum were estimated.

  17. A theoretical quantum chemical study of alanine formation in interstellar medium

    Science.gov (United States)

    Shivani; Pandey, Parmanad; Misra, Alka; Tandon, Poonam

    2017-08-01

    The interstellar medium, the vast space between the stars, is a rich reservoir of molecular material ranging from simple diatomic molecules to more complex, astrobiologically important molecules such as amino acids, nucleobases, and other organic species. Radical-radical and radical-neutral interaction schemes are very important for the formation of comparatively complex molecules in low temperature chemistry. An attempt has been made to explore the possibility of formation of complex organic molecules in interstellar medium, through detected interstellar molecules like CH3CN and HCOOH. The gas phase reactions are theoretically studied using quantum chemical techniques. We used the density functional theory (DFT) at the B3LYP/6-311G( d, p) level. The reaction energies, potential barrier and optimized structures of all the geometries, involved in the reaction path, has been discussed. We report the potential energy surfaces for the reactions considered in this work.

  18. Wireless Information-Theoretic Security in an Outdoor Topology with Obstacles: Theoretical Analysis and Experimental Measurements

    Directory of Open Access Journals (Sweden)

    Dagiuklas Tasos

    2011-01-01

    Full Text Available This paper presents a Wireless Information-Theoretic Security (WITS scheme, which has been recently introduced as a robust physical layer-based security solution, especially for infrastructureless networks. An autonomic network of moving users was implemented via 802.11n nodes of an ad hoc network for an outdoor topology with obstacles. Obstructed-Line-of-Sight (OLOS and Non-Line-of-Sight (NLOS propagation scenarios were examined. Low-speed user movement was considered, so that Doppler spread could be discarded. A transmitter and a legitimate receiver exchanged information in the presence of a moving eavesdropper. Average Signal-to-Noise Ratio (SNR values were acquired for both the main and the wiretap channel, and the Probability of Nonzero Secrecy Capacity was calculated based on theoretical formula. Experimental results validate theoretical findings stressing the importance of user location and mobility schemes on the robustness of Wireless Information-Theoretic Security and call for further theoretical analysis.

  19. Potential determinants of health-care professionals' use of survivorship care plans: a qualitative study using the theoretical domains framework.

    Science.gov (United States)

    Birken, Sarah A; Presseau, Justin; Ellis, Shellie D; Gerstel, Adrian A; Mayer, Deborah K

    2014-11-15

    Survivorship care plans are intended to improve coordination of care for the nearly 14 million cancer survivors in the United States. Evidence suggests that survivorship care plans (SCPs) have positive outcomes for survivors, health-care professionals, and cancer programs, and several high-profile organizations now recommend SCP use. Nevertheless, SCP use remains limited among health-care professionals in United States cancer programs. Knowledge of barriers to SCP use is limited in part because extant studies have used anecdotal evidence to identify determinants. This study uses the theoretical domains framework to identify relevant constructs that are potential determinants of SCP use among United States health-care professionals. We conducted semi-structured interviews to assess the relevance of 12 theoretical domains in predicting SCP use among 13 health-care professionals in 7 cancer programs throughout the United States with diverse characteristics. Relevant theoretical domains were identified through thematic coding of interview transcripts, identification of specific beliefs within coded text units, and mapping of specific beliefs onto theoretical constructs. We found the following theoretical domains (based on specific beliefs) to be potential determinants of SCP use: health-care professionals' beliefs about the consequences of SCP use (benefit to survivors, health-care professionals, and the system as a whole); motivation and goals regarding SCP use (advocating SCP use; extent to which using SCPs competed for health-care professionals' time); environmental context and resources (whether SCPs were delivered at a dedicated visit and whether a system, information technology, and funding facilitated SCP use); and social influences (whether using SCPs is an organizational priority, influential people support SCP use, and people who could assist with SCP use buy into using SCPs). Specific beliefs mapped onto the following psychological constructs: outcome

  20. An experimental and theoretical study of the valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine

    Science.gov (United States)

    Holland, D. M. P.; Powis, I.; Trofimov, A. B.; Menzies, R. C.; Potts, A. W.; Karlsson, L.; Badsyuk, I. L.; Moskovskaya, T. E.; Gromov, E. V.; Schirmer, J.

    2017-10-01

    The valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine have been studied both experimentally and theoretically. Synchrotron radiation has been employed to record angle resolved photoelectron spectra in the photon energy range 20-100 eV, and these have enabled anisotropy parameters and branching ratios to be derived. The experimental results have been compared with theoretical predictions obtained using the continuum multiple scattering Xα approach. This comparison shows that the anisotropy parameter associated with the nominally chlorine lone-pair orbital lying in the molecular plane is strongly affected by the atomic Cooper minimum. In contrast, the photoionization dynamics of the second lone-pair orbital, orientated perpendicular to the molecular plane, seem relatively unaffected by this atomic phenomenon. The outer valence ionization has been studied theoretically using the third-order algebraic-diagrammatic construction (ADC(3)) approximation scheme for the one-particle Green's function, the outer valence Green's function method, and the equation-of-motion (EOM) coupled cluster (CC) theory at the level of the EOM-IP-CCSD and EOM-EE-CC3 models. The convergence of the results to the complete basis set limit has been investigated. The ADC(3) method has been employed to compute the complete valence shell ionization spectra of 2-chloropyridine and 3-chloropyridine. The relaxation mechanism for ionization of the nitrogen σ-type lone-pair orbital (σN LP) has been found to be different to that for the corresponding chlorine lone-pair (σCl LP). For the σN LP orbital, π-π* excitations play the main role in the screening of the lone-pair hole. In contrast, excitations localized at the chlorine site involving the chlorine πCl LP lone-pair and the Cl 4p Rydberg orbital are the most important for the σCl LP orbital. The calculated photoelectron spectra have allowed assignments to be proposed for most of the structure observed in the

  1. Theoretical-Experimental study on the electroslag remelting technology of high quality steels

    International Nuclear Information System (INIS)

    Robles P, E.F.

    1993-01-01

    This is a theoretical-experimental laboratory study on the Electroslag Remelting Technology (ESRT) of high quality steels. The objective of this study was to analyze the problems that this technology entails and thus facilitate its industrial application in Mexico. The study was carried out using a 1 Kg. capacity furnace, the behavior of different fluxes on the remelting of 1018 AISI carbon steel was established and a slag 70F/15/15 was selected for the remelting of H-13 AISI hot work tool steel. From the experimental results it was possible to establish a flux manufacture route, the electrode conditioning necessary for the experiments, and the critical points of the process. It was demonstrated that the crucible and electrode advance system are the more critical points in the furnace manufacture, that the start up is fundamental for the remelting continuity and that the CaF 2 base slags are more recommendable for special steels refining. It has been proven that it is possible to experiment with little laboratory electroslag furnaces. (Author)

  2. Theoretical studies of growth processes and electronic properties of nanostructures on surfaces

    Science.gov (United States)

    Mo, Yina

    Low dimensional nanostructures have been of particular interest because of their potential applications in both theoretical studies and industrial use. Although great efforts have been put into obtaining better understanding of the formation and properties of these materials, many questions still remain unanswered. This thesis work has focused on theoretical studies of (1) the growth processes of magnetic nanowires on transition-metal surfaces, (2) the dynamics of pentacene thin-film growth and island structures on inert surfaces, and (3) our proposal of a new type of semiconducting nanotube. In the first study, we elucidated a novel and intriguing kinetic pathway for the formation of Fe nanowires on the upper edge of a monatomic-layer-high step on Cu(111) using first-principles calculations. The identification of a hidden fundamental Fe basal line within the Cu steps prior to the formation of the apparent upper step edge Fe wire produces a totally different view of step-decorating wire structures and offers new possibilities for the study of the properties of these wires. Subsequent experiments with scanning tunneling microscopy unambiguously established the essential role of embedded Fe atoms as precursors to monatomic wire growth. A more general study of adatom behavior near transition-metal step edges illustrated a systematic trend in the adatom energetics and kinetics, resulted from the electronic interactions between the adatom and the surfaces. This work opens the possibility of controlled manufacturing of one-dimensional nanowires. In the second study, we investigated pentacene thin-films on H-diamond, H-silica and OH-silica surfaces via force field molecular dynamics simulations. Pentacene island structures on these surfaces were identified and found to have a 90-degree rotation relative to the structure proposed by some experimental groups. Our work may facilitate the design and control of experimental pentacene thin-film growth, and thus the development

  3. Theoretical study of Cherenkov radiation emission in anisotropic uniaxial crystals

    Energy Technology Data Exchange (ETDEWEB)

    Delbart, A; Derre, J

    1996-04-01

    A theoretical review of the Cherenkov radiation emission in uniaxial crystals is presented. The formalism of C. Muzicar in terms of energetic properties of the emitted waves are corrected. This formalism is used to simulate the Cherenkov radiation emission in a strongly birefringent sodium nitrate crystal (NaNO{sub 3}) and to investigate the consequences of the slight anisotropy of sapphire (Al{sub 2}O{sub 3}) on the design of the Optical Trigger. (author). 12 refs. Submitted to Physical Review, D (US).

  4. Experimental and theoretical studies of perceptible color fading of decorative paints consisting of mixed pigments

    International Nuclear Information System (INIS)

    Auger, Jean-Claude; McLoughlin, Daragh

    2017-01-01

    We study the color fading of paints films composed of mixtures of white rutile titanium dioxide and yellow arylide pigments dispersed in two polymer binders at different volume concentrations. The samples were exposed to ultraviolet radiations in an accelerated weathering tester during three weeks. The measured patterns in color variations appeared to be independent of the chemistry of the binders. We then developed a theoretical framework, based on the Radiative transfer Equation of light and the One Particle T-Matrix formalism to simulate the color fading process. The loss of color is correlated to the progressive decrease of the original colored pigment volume-filling fraction as the destructive UV radiations penetrate deeper into the films. The calculated patterns of color variations of paints film composed by mixtures of white pigments with yellow Cadmium Sulfate (CdS) and red Cerium Sulfide (Ce_2S_3) pigments showed the same trend as that seen experimentally. - Highlights: • Theoretical framework to simulate color-fading process of paints. • Good comparison between simulation and experimental data. • Color Fading depends on total amount of perceptible pigments.

  5. Experimental and theoretical study on field emission properties of zinc oxide nanoparticles decorated carbon nanotubes

    International Nuclear Information System (INIS)

    Li Xin; Zhou Wei-Man; Liu Wei-Hua; Wang Xiao-Li

    2015-01-01

    Field emission properties of zinc oxide (ZnO) nanoparticles (NPs) decorated carbon nanotubes (CNTs) are investigated experimentally and theoretically. CNTs are in situ decorated with ZnO NPs during the growth process by chemical vapor deposition using a carbon source from the iron phthalocyanine pyrolysis. The experimental field emission test shows that the ZnO NP decoration significantly improves the emission current from 50 μA to 275 μA at 550 V and the reduced threshold voltage from 450 V to 350 V. The field emission mechanism of ZnO NPs on CNTs is theoretically studied by the density functional theory (DFT) combined with the Penn–Plummer method. The ZnO NPs reconstruct the ZnO–CNT structure and pull down the surface barrier of the entire emitter system to 0.49 eV so as to reduce the threshold electric field. The simulation results suggest that the presence of ZnO NPs would increase the LDOS near the Fermi level and increase the emission current. The calculation results are consistent with the experiment results. (paper)

  6. Economic growth factors system: theoretical and methodological aspect

    OpenAIRE

    H.Ya. Hlukha

    2014-01-01

    The aim of the article. The main objective of the article is to create theoretical grounds to build the system of economic growth factors, to modernize their classification, to define exogenous and endogenous factors, to analyze them within the state economic policy structure. The results of the analysis. The article focuses on economic growth factors theoretical studies: - economic growth factors classification characteristics have been highlighted; - various approaches to determine...

  7. Fluoride Anion Recognition by a Multifunctional Urea Derivative: An Experimental and Theoretical Study

    Directory of Open Access Journals (Sweden)

    Jana Schiller

    2016-05-01

    Full Text Available In this work we demonstrate the ability of a multifaceted N,N′-disubstituted urea to selectively recognize fluoride anion (F− among other halides. This additional function is now added to its already reported organocatalytic and organogelator properties. The signaling mechanism relies on the formation of a charge-transfer (CT complex between the urea-based sensor and F¯ in the ground state with a high association constant as demonstrated by absorption and fluorescence spectroscopy. The nature of the hydrogen bonding interaction between the sensor and F¯ was established by 1H-NMR studies and theoretical calculations. Moreover, the recovery of the sensor was achieved by addition of methanol.

  8. Theoretical optical spectroscopy of complex systems

    Energy Technology Data Exchange (ETDEWEB)

    Conte, A. Mosca, E-mail: adriano.mosca.conte@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Violante, C., E-mail: claudia.violante@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Missori, M., E-mail: mauro.missori@isc.cnr.it [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Via Salaria Km 29.300, 00016 Monterotondo Scalo (Rome) (Italy); Bechstedt, F., E-mail: bech@ifto.physik.uni-jena.de [Institut fur Festkorpertheorie und -optik, Friedrich-Schiller-Universitat, Max-Wien-Platz 1, 07743 Jena (Germany); Teodonio, L. [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Istituto centrale per il restauro e la conservazione del patrimonio archivistico e librario (IC-RCPAL), Italian Minister for Cultural Heritage, Via Milano 76, 00184 Rome (Italy); Ippoliti, E.; Carloni, P. [German Research School for Simulation Sciences, Julich (Germany); Guidoni, L., E-mail: leonardo.guidoni@univaq.it [Università degli Studi di L’Aquila, Dipartimento di Chimica e Materiali, Via Campo di Pile, 67100 L’Aquila (Italy); Pulci, O., E-mail: olivia.pulci@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy)

    2013-08-15

    Highlights: ► We review some theoretical condensed matter ab initio spectroscopic computational techniques. ► We show several applications ranging from 0 to 3 dimensional systems. ► For each system studied, we show which kind of information it is possible to obtain by performing these calculations. -- Abstract: We review here some of the most reliable and efficient computational theoretical ab initio techniques for the prediction of optical and electronic spectroscopic properties and show some important applications to molecules, surfaces, and solids. We investigate the role of the solvent in the optical absorption spectrum of indole molecule. We study the excited-state properties of a photo-active minimal model molecule for the retinal of rhodopsin, responsible for vision mechanism in animals. We then show a study about spectroscopic properties of Si(1 1 1) surface. Finally we simulate a bulk system: paper, that is mainly made of cellulose, a pseudo-crystalline material representing 40% of annual biomass production in the Earth.

  9. Theoretical optical spectroscopy of complex systems

    International Nuclear Information System (INIS)

    Conte, A. Mosca; Violante, C.; Missori, M.; Bechstedt, F.; Teodonio, L.; Ippoliti, E.; Carloni, P.; Guidoni, L.; Pulci, O.

    2013-01-01

    Highlights: ► We review some theoretical condensed matter ab initio spectroscopic computational techniques. ► We show several applications ranging from 0 to 3 dimensional systems. ► For each system studied, we show which kind of information it is possible to obtain by performing these calculations. -- Abstract: We review here some of the most reliable and efficient computational theoretical ab initio techniques for the prediction of optical and electronic spectroscopic properties and show some important applications to molecules, surfaces, and solids. We investigate the role of the solvent in the optical absorption spectrum of indole molecule. We study the excited-state properties of a photo-active minimal model molecule for the retinal of rhodopsin, responsible for vision mechanism in animals. We then show a study about spectroscopic properties of Si(1 1 1) surface. Finally we simulate a bulk system: paper, that is mainly made of cellulose, a pseudo-crystalline material representing 40% of annual biomass production in the Earth

  10. Data, Methods, and Theoretical Implications

    Science.gov (United States)

    Hannagan, Rebecca J.; Schneider, Monica C.; Greenlee, Jill S.

    2012-01-01

    Within the subfields of political psychology and the study of gender, the introduction of new data collection efforts, methodologies, and theoretical approaches are transforming our understandings of these two fields and the places at which they intersect. In this article we present an overview of the research that was presented at a National…

  11. An e-Learning Theoretical Framework

    Science.gov (United States)

    Aparicio, Manuela; Bacao, Fernando; Oliveira, Tiago

    2016-01-01

    E-learning systems have witnessed a usage and research increase in the past decade. This article presents the e-learning concepts ecosystem. It summarizes the various scopes on e-learning studies. Here we propose an e-learning theoretical framework. This theory framework is based upon three principal dimensions: users, technology, and services…

  12. Study of cognitive sphere in children and adolescents with congenital myopathy (theoretical review

    Directory of Open Access Journals (Sweden)

    V. A. Erokhina

    2013-08-01

    Full Text Available This paper presents an analysis of current approaches to the study of states of higher mental functions in children and adolescents suffering from various forms of hereditary myopathies. The aim of this work is to study the theoretical rationale and the possibility of specific disorders of mental function in children and adolescents with congenital myopathies. To achieve this objective during the study it was necessary to solve the following problems: give a description of the various groups and forms of congenital myopathies, their clinical characteristics; justify the possibility of considering the hereditary myopathies as a factor in the formation of changes in visual-spatial activities and thinking; evaluate the possibility to use complex neuropsychological psycho-diagnostic techniques for investigating the state of the higher mental functions of children with congenital myopathies. The possibility of neuropsychological correction for this category of patients is discussed also.

  13. FT-Raman and FTIR spectra of photoactive aminobenzazole derivatives in the solid state: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Rodrigo Martins [Universidade Federal do Pampa, Campus Bagé, Grupo de Pesquisa em Espectroscopia de Materiais Fotônicos, 96400-970 Bagé, RS (Brazil); Rodembusch, Fabiano Severo [Universidade Federal do Rio Grande do Sul, Grupo de Pesquisa em Fotoquímica Orgânica Aplicada, Av. Bento Gonçalves 9500, CEP 91501-970 Porto Alegre, RS (Brazil); Habis, Charles [Northern Virginia Community College, Manassas, VA (United States); Moreira, Eduardo Ceretta, E-mail: eduardomoreira@unipampa.edu.br [Universidade Federal do Pampa, Campus Bagé, Grupo de Pesquisa em Espectroscopia de Materiais Fotônicos, 96400-970 Bagé, RS (Brazil)

    2014-12-15

    This study reports the experimental investigation of two photoactive aminobenzazole derivatives in the solid state by FT-Raman and Infrared Spectroscopies (FTIR) and its comparison with theoretical models. The optimized molecular structure, vibrational frequencies, and corresponding vibrational assignments of these compounds have been investigated experimentally and theoretically using Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA) and Gaussian03 Software Package. The FT-Raman and FTIR spectra were acquired with high resolution and emission frequencies identified by simulating the vibrational modes. The most intense peak observed in the FT-Raman spectra is the in-plane deformation vibrational of O–H bond that could be related to the vibrational region responsible for the stabilization of the enol conformer in the ground state which undergoes ESIPT to form a keto tautomer in the excited state. Additionally, the position of the amino group played an important role on the vibrational characteristics of the studied compounds. Also, the simulations proved to be a good approach in undertaking the FTIR and FT-Raman experiments. The use of graphic correlations helps us to determine the method and basis that best fit the experimental results. - Highlights: • Structural and vibrational properties of two aminobenzazoles were reported. • Comparison between experimental techniques and theoretical models. • The position of the amino group played an important role on the vibrational characteristics of the studied compounds.

  14. Experimental and theoretical study of microalgal competition in laboratory and natural ecosystems

    Science.gov (United States)

    Pisman, T. I.; Somova, L. A.

    An important aspect of studying mixed cultures of microalgae is the artificial ecosystems containing algal culture as a regeneration link and a source of vegetable substances. The peculiarities of studying the stability of microalgae mixed cultures in the laboratory and natural environment have been considered in the work. The role of factors most essentially affecting the species structure of phytoplankton community (temperature factor, light intensity, pH environments, elements of mineral nutrition, algal metabolites, predation and fluctuation of environmental conditions) has been displayed. As a result of experimental and theoretical modelling of the microalgae Chlorella vulgaris and Scenedesmus quadricauda competition under limitation on nitrogen, the impossibility of their co-existence has been revealed. Under these conditions Chl. vulgaris turned out to be less competitive than Sc. quadricauda. The influence of the ratio of biogenic elements concentration in the environment, which should be recognized as an independent regulatory factor limiting growth of populations in the community and, thus affecting its structure, has been analyzed.

  15. Theoretical study of alignment and orientation of n = 2 levels in Li++He collision

    International Nuclear Information System (INIS)

    Courbin, C.; Sidis, V.

    1986-01-01

    The determination of alignment and orientation parameters from differential cross section measurements involving the photon-particle coincidence technique prompts theory to investigate a wide variety of electronic transitions both at small and large distances of approach between the collision partners. A theoretical model is presented with a view to explaining alignment and orientation phenomena related to Li + +He*(2 1 P) excitation and Li*(2 2 P)+He + charge exchange excitation in the prototype Li + +He collision. The corresponding discussion is illustrated using a recent ab initio study by the authors [fr

  16. Theoretical study of elastic electron scattering off stable and exotic nuclei

    International Nuclear Information System (INIS)

    Roca-Maza, X.; Centelles, M.; Salvat, F.; Vinas, X.

    2008-01-01

    Results for elastic electron scattering by nuclei, calculated with charge densities of Skyrme forces and covariant effective Lagrangians that accurately describe nuclear ground states, are compared against experiment in stable isotopes. Dirac partial-wave calculations are performed with an adapted version of the ELSEPA package. Motivated by the fact that studies of electron scattering off exotic nuclei are intended in future facilities in the commissioned GSI and RIKEN upgrades, we survey the theoretical predictions from neutron-deficient to neutron-rich isotopes in the tin and calcium isotopic chains. The charge densities of a covariant interaction that describes the low-energy electromagnetic structure of the nucleon within the Lagrangian of the theory are used to this end. The study is restricted to medium- and heavy-mass nuclei because the charge densities are computed in mean-field approach. Because the experimental analysis of scattering data commonly involves parameterized charge densities, as a surrogate exercise for the yet unexplored exotic nuclei, we fit our calculated mean-field densities with Helm model distributions. This procedure turns out to be helpful to study the neutron-number variation of the scattering observables and allows us to identify correlations of potential interest among some of these observables within the isotopic chains

  17. Theoretical study of the properties of X-ray diffraction moiré fringes. I

    International Nuclear Information System (INIS)

    Yoshimura, Jun-ichi

    2015-01-01

    A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory, where the effect of the Pendellösung intensity oscillation on the moiré pattern is explained in detail. A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997 ▸). Acta Cryst. A53, 810–812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellösung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general

  18. Theoretical studies of positron states and annihilation characteristics at the oxidized Cu(100) surface

    Energy Technology Data Exchange (ETDEWEB)

    Fazleev, N. G. [Department of Physics, Box 19059, University of Texas at Arlington, Arlington Texas 76019 (United States) and Institute of Physics, Kazan Federal University, Kremlevskaya18, Kazan 420008 (Russian Federation); Weiss, A. H. [Department of Physics, Box 19059, University of Texas at Arlington, Arlington Texas 76019 (United States)

    2013-04-19

    In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. An ab-initio study of the electronic properties of the Cu(100) missing row reconstructed surface at various on surface and sub-surface oxygen coverages has been performed on the basis of the density functional theory (DFT) using the Dmol3 code and the generalized gradient approximation (GGA). Surface structures in calculations have been constructed by adding oxygen atoms to various surface hollow and sub-surface octahedral sites of the 0.5 monolayer (ML) missing row reconstructed phase of the Cu(100) surface with oxygen coverages ranging from 0.5 to 1.5 ML. The charge redistribution at the surface and variations in atomic structure and chemical composition of the topmost layers associated with oxidation and surface reconstruction have been found to affect the spatial extent and localization of the positron surface state wave function and annihilation probabilities of surface trapped positrons with relevant core electrons. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). It has been shown that positron annihilation probabilities with Cu 3s and 3p core electrons decrease when total (on-surface and sub-surface) oxygen coverage of the Cu(100) surface increases up to 1 ML. The calculations show that for high oxygen coverage when total oxygen coverage is 1. 5 ML the positron is not bound to the surface.

  19. A Computational and Theoretical Study of Conductance in Hydrogen-bonded Molecular Junctions

    Science.gov (United States)

    Wimmer, Michael

    This thesis is devoted to the theoretical and computational study of electron transport in molecular junctions where one or more hydrogen bonds are involved in the process. While electron transport through covalent bonds has been extensively studied, in recent work the focus has been shifted towards hydrogen-bonded systems due to their ubiquitous presence in biological systems and their potential in forming nano-junctions between molecular electronic devices and biological systems. This analysis allows us to significantly expand our comprehension of the experimentally observed result that the inclusion of hydrogen bonding in a molecular junction significantly impacts its transport properties, a fact that has important implications for our understanding of transport through DNA, and nano-biological interfaces in general. In part of this work I have explored the implications of quasiresonant transport in short chains of weakly-bonded molecular junctions involving hydrogen bonds. I used theoretical and computational analysis to interpret recent experiments and explain the role of Fano resonances in the transmission properties of the junction. In a different direction, I have undertaken the study of the transversal conduction through nucleotide chains that involve a variable number of different hydrogen bonds, e.g. NH˙˙˙O, OH˙˙˙O, and NH˙˙˙N, which are the three most prevalent hydrogen bonds in biological systems and organic electronics. My effort here has focused on the analysis of electronic descriptors that allow a simplified conceptual and computational understanding of transport properties. Specifically, I have expanded our previous work where the molecular polarizability was used as a conductance descriptor to include the possibility of atomic and bond partitions of the molecular polarizability. This is important because it affords an alternative molecular description of conductance that is not based on the conventional view of molecular orbitals as

  20. Theoretical Advanced Study Institute in Elementary Particle Physics

    CERN Document Server

    2017-01-01

    The program will consist of a pedagogical series of lectures and seminars. Lectures will be given over a four-week period, three or four lectures per day, Monday through Friday. The audience will be composed primarily of advanced theoretical graduate students. Experimentalists with a strong background in theory are also encouraged to apply. Some post-doctoral fellows will be admitted, but preference will be given to applicants who will not have received their Ph.D. before 2017. The minimum background needed to get full benefit of TASI is a knowledge of quantum field theory (including RGEs) and familiarity with the Standard Model. Some familiarity with SUSY would be helpful. We hope to provide some subsidy, but students will need partial support from other sources. Rooms, meals, and access to all facilities will be provided at reasonable rates in beautifully located dormitories at the University of Colorado.

  1. Experimental and theoretical study of very-low-energy inelastic processes in electron-molecule collisions, March 20, 1981-March 20, 1982

    International Nuclear Information System (INIS)

    Golden, D.E.; Morrison, M.

    1982-01-01

    We have undertaken a comprehensive theoretical and experimental study of very-low-energy electron-impact excitation of molecules. The objective of the first phase of this program is a comprehensive study of near-threshold electron-impact ro-vibrational excitation cross sections in H 2 in order to resolve serious discrepancies that exist between the cross sections for this process as determined by beam and swarm experiments. The program consists of experimental measurements of these cross sections using a cross-beam time-of-flight apparatus being developed in our laboratory and fully ab-initio theoretical calculations of these cross sections using a coupled-channels formulation with a highly-accurate interaction potential. Progress is reported

  2. Theoretical study on alkyne-linked carbazole polymers for blue-light multifunctional materials

    International Nuclear Information System (INIS)

    Yi Ling; Wang Xueye

    2011-01-01

    This paper studied poly[(3,6-di-tert-butyl-N-hexadecyl-1,8-carbazolylene) butadiynylene] (P1), butadiynylene-linked poly (3,6-carbazole) (P2) and butadiynylene-linked poly (2,7-carbazole) (P3) through the theoretical measurements with Gaussian 03 program package. To investigate the relationship between structures and properties of these multifunctional electroluminescent materials, their geometrical structures of ground and excited-states were optimized by B3LYP/6-31G (d) and CIS/6-31G (d) methods, respectively. The lowest excitation energies (E g 's), and the maximum absorption and emission wavelengths of these polymers were calculated by time-dependent density functional theory methods (TD-DFT). The important parameters for luminescent materials were also predicated including the ionization potentials (I p 's) and electron affinities (E a 's). The calculated results show that the highest-occupied molecular orbital (HOMO) energies lift about 0.27-0.49 eV compared to N,N'-bis(naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB), suggesting the significant improved hole-accepting and transporting abilities. In addition, substitution of alkyne for carbazole resulted in a narrow band gap and a red shift of both the absorption and emission peaks. Through above calculations, it is evidenced that these polymers can be considered as candidates for excellent OLEDs with good hole-creating abilities and high blue-light emission. - Highlights: → We studied poly [(3,6-di-tert-butyl-N-hexadecyl-1,8-carbazolylene) butadiynylene] by theoretical method. → The geometrical structures of ground and excited-states had been optimized by B3LYP/6-31G (d) and CIS/6-31G (d). → The relationship between structures and properties of these multifunctional electroluminescent materials had been investigated. → These molecules are excellent candidates for multifunctional OLED materials. → The substitution of alkyne for carbazole results in a narrow band gap and a red shift of both

  3. Factors that influence effective perioperative temperature management by anesthesiologists: a qualitative study using the Theoretical Domains Framework.

    Science.gov (United States)

    Boet, Sylvain; Patey, Andrea M; Baron, Justine S; Mohamed, Karim; Pigford, Ashlee-Ann E; Bryson, Gregory L; Brehaut, Jamie C; Grimshaw, Jeremy M

    2017-06-01

    Inadvertent perioperative hypothermia (IPH) is associated with a range of adverse outcomes. Safe and effective warming techniques exist to prevent IPH; however, IPH remains common. This study aimed to identify factors that anesthesiologists perceive may influence temperature management during the perioperative period. After Research Ethics Board approval, semi-structured interviews were conducted with staff anesthesiologists at a Canadian academic hospital. An interview guide based on the Theoretical Domains Framework (TDF) was used to capture 14 theoretical domains that may influence temperature management. The interview transcripts were coded using direct content analysis to generate specific beliefs and to identify relevant TDF domains perceived to influence temperature management behaviour. Data saturation was achieved after 15 interviews. The following nine theoretical domains were identified as relevant to designing an intervention for practices in perioperative temperature management: knowledge, beliefs about capabilities, beliefs about consequences, reinforcement, memory/attention/decision-making, environmental context and resources, social/professional role/identity, social influences, and behavioural regulation. Potential target areas to improve temperature management practices include interventions that address information needs about individual temperature management behaviour as well as patient outcome (feedback), increasing awareness of possible temperature management strategies and guidelines, and a range of equipment and surgical team dynamics that influence temperature management. This study identified several potential target areas for future interventions from nine of the TDF behavioural domains that anesthesiologists perceive to drive their temperature management practices. Future interventions that aim to close the evidence-practice gap in perioperative temperature management may include these targets.

  4. Annual progress report for 1985 of Theoretical Physics Division

    International Nuclear Information System (INIS)

    Rastogi, B.P.

    1986-01-01

    This report presents a resume of the work done in the Theoretical Physics Division during the calender year, 1985. The topics covered are described by their brief summaries. The main fields of the work were : (a) physics design of the 500 MWe PHWR and related developmental studies, (b) reactor physics work related to Rajasthan, Narora and Tarapur stations, (c) laser fusion studies, (d) mathematical physics studies on Monte-Carlo method, transport equation and Fokker-Planck Equation and (e) theoretical physics studies related to Feynman path integrals and quantum optics. The lists of research publications and Trombay Colloquia organised are also appended. (author)

  5. Theoretical studies of the electronic structure of the ions KCs+ and RbCs+

    International Nuclear Information System (INIS)

    Abdul Al, Saleh Nabhan

    2000-01-01

    by Perturbation of multiconfiguration wave functions Selected Iteratively) algorithm of the Laboratoire de Physique Quantique (Toulouse, France). The variation of the potential energy with the internuclear distance has been estimated for lowest molecular states of the ions KCs + and RbCs + . Extensive tables of energy values versus internuclear distance are tabulated. These extensive tables of energy values are also being displayed at the following address: http://hplasim2.univ-lyon1.fr/allouche. Then, we are able to derive the molecular spectroscopic constants for the bound states with regular shape of the two ions. It is possible to dissociate in teh wave function, the effect of rotation from the pure vibration wave function by using the canonical approach. Whence, we can find the energy eigenvalues of some vibrational levels and deduce the corresponding rotational and centrifugal distortion constants (CDC). To the best of our knowledge, neither theoretical nor experimental studies are available in the literature for molecular ions KCs + and RbCs +

  6. Theoretical concepts about "Intelligence" - practices and standards in democratic societies

    OpenAIRE

    Mr.Sc. Bahri Gashi

    2013-01-01

    My thesis consists of theoretical analysis on the need for recognition of academic concepts to shape and design research field intelligence community activity, careful analysis of the terms and concepts that are strongly linked to intelligence work methodology, theoretical aspects description given practice best to regulate this specific area in our academic studies, has made the study to take proper shape with bold shades of comparative empirical analysis. My study aims to summarize, to ...

  7. A theoretical study of the structure and thermochemical properties of alkali metal fluoroplumbates MPbF3.

    Science.gov (United States)

    Boltalin, A I; Korenev, Yu M; Sipachev, V A

    2007-07-19

    Molecular constants of MPbF3 (M=Li, Na, K, Rb, and Cs) were calculated theoretically at the MP2(full) and B3LYP levels with the SDD (Pb, K, Rb, and Cs) and cc-aug-pVQZ (F, Li, and Na) basis sets to determine the thermochemical characteristics of the substances. Satisfactory agreement with experiment was obtained, including the unexpected nonmonotonic dependence of substance dissociation energies on the alkali metal atomic number. The bond lengths of the theoretical CsPbF3 model were substantially elongated compared with experimental estimates, likely because of errors in both theoretical calculations and electron diffraction data processing.

  8. 3. Theoretical Physics Division

    International Nuclear Information System (INIS)

    For the period September 1980 - Aug 1981, the studies in theoretical physics divisions have been compiled under the following headings: in nuclear physics, nuclear structure, nuclear reactions and intermediate energies; in particle physics, NN and NantiN interactions, dual topological unitarization, quark model and quantum chromodynamics, classical and quantum field theories, non linear integrable equations and topological preons and Grand unified theories. A list of publications, lectures and meetings is included [fr

  9. Theoretical and experimental studies on a magnetorheological brake operating under compression plus shear mode

    International Nuclear Information System (INIS)

    Sarkar, C; Hirani, H

    2013-01-01

    The torque characteristics of magnetorheological brakes, consisting of rotating disks immersed in a MR fluid and enclosed in an electromagnetic casing, are controlled by regulating the yield stress of the MR fluid. An increase in yield stress increases the braking torque, which means that the higher the yield strength of the MR fluid, the better the performance of the MR brake will be. In the present research an application of compressive force on MR fluid has been proposed to increase the torque capacity of MR brakes. The mathematical expressions to estimate the torque values for MR brake, operating under compression plus shear mode accounting Herschel–Bulkley shear thinning model, have been detailed. The required compressive force on MR fluid of the proposed brake has been applied using an electromagnetic actuator. The development of a single-plate MR disk brake and an experimental test rig are described. Experiments have been performed to illustrate braking torque under different control currents (0.0–2.0 A). The torque results have been plotted and compared with theoretical study. Experimental results as well as theoretical calculations indicate that the braking torque of the proposed MR brake is higher than that of the MR brake operating only under shear. (paper)

  10. Theoretical study of fuel element reliability in the BRIG-300 fast reactor

    International Nuclear Information System (INIS)

    Kulikov, I.S.; Nesterenko, V.B.; Tverkovkin, B.E.

    1983-01-01

    The theoretical results on studies of the reliability of cermet symmetrically heated fuel elements under conditions of the BRIG-300 fast gas cooled reactor are presented. The investigations have been conducted at the Nuclear Power Engineering Institute of the Byelorussian Academy of Sciences. Two variants of the fuel elements are considered :the fuel element with the gas gap between fuel and can and the fuel element with tight contact between cermet fuel and can. The estimated data on can resistance, swelling of the fuel rods and cans, strains and stresses in cans, change of the gap and its thermal coductivity during the reactor operation are obtained. The results of the analysis show that cermet fuel has sufficient reliability upon oparational conditions of the reactor with dissociating gas coolant in a steady-state regime

  11. Theoretical study of pressure dependence of transition temperature of In and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Priyank, E-mail: priyank-kumar2007@yahoo.co.in [Department of Science, Government Polytechnic, Gandhinagar -382024, Gujarat (India); Bhatt, N. K. [Department of Physics, Sardar Patel University, Vallabh Vidyanagar - 388120, Gujarat (India); Vyas, P. R.; Gohel, V. B. [Department of Physics, School of Science, Gujarat University, Ahmedabad - 380009, Gujarat (India)

    2015-08-28

    Recently proposed structured local pseudopotential (PP) by Fiolhais et al. has been successfully used to compute superconducting state parameters (SSP): electron-phonon coupling strength (λ), Coulomb pseudopotential (μ*), critical temperature (T{sub c}), effective interaction strength (N{sub 0}V), isotopic effect parameter (α) and their pressure dependence of non-transition metals In and Pb as a test case. Pressure dependence of the Debye temperature has been computed by Gruneisen model. Present results are in good agreement with experimental and other theoretical results. Present study has been further extended to estimate volume (critical volume) at which λ=μ*, where Tc and N{sub 0}V becomes zero. The presently used model is found to be transferable at the extreme environment without any adjustment of parameters further alongwith its simplicity and predictivity.

  12. Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Alessandra Souza [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Varella, Márcio T. do N. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, SP (Brazil); Sanchez, Sergio d’A.; Bettega, Márcio H. F., E-mail: bettega@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Ameixa, João; Limão-Vieira, Paulo; Ferreira da Silva, Filipe [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, Francisco [Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); and others

    2016-08-28

    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.

  13. Discriminating Properties of Alkali Metal Ions Towards the Constituents of Proteins and Nucleic Acids. Conclusions from Gas-Phase and Theoretical Studies.

    Science.gov (United States)

    Rodgers, Mary T; Armentrout, Peter B

    2016-01-01

    Quantitative insight into the structures and thermodynamics of alkali metal cations interacting with biological molecules can be obtained from studies in the gas phase combined with theoretical work. In this chapter, the fundamentals of the experimental and theoretical techniques are first summarized and results for such work on complexes of alkali metal cations with amino acids, small peptides, and nucleobases are reviewed. Periodic trends in how these interactions vary as the alkali metal cations get heavier are highlighted.

  14. Theoretical studies on the inactivation mechanism of γ-aminobutyric acid aminotransferase.

    Science.gov (United States)

    Durak, A T; Gökcan, H; Konuklar, F A S

    2011-07-21

    The inactivation mechanism of γ-aminobutyric acid aminotransferase (GABA-AT) in the presence of γ-vinyl-aminobutyric acid, an anti-epilepsy drug, has been studied by means of theoretical calculations. Density functional theory methods have been applied to compare the three experimentally proposed inactivation mechanisms (Silverman et al., J. Biol. Chem., 2004, 279, 363). All the calculations were performed at the B3LYP/6-31+G(d,p) level of theory. Single point solvent calculations were carried out in water, by means of an integral equation formalism-polarizable continuum model (IEFPCM) at the B3LYP/6-31+G(d,p) level of theory. The present calculations provide an insight into the mechanistic preferences of the inactivation reaction of GABA-AT. The results also allow us to elucidate the key factors behind the mechanistic preferences. The computations also confirm the importance of explicit water molecules around the reacting center in the proton transfer steps.

  15. Biometric security from an information-theoretical perspective

    NARCIS (Netherlands)

    Ignatenko, T.; Willems, F.M.J.

    2012-01-01

    In this review, biometric systems are studied from an information theoretical point of view. In the first part biometric authentication systems are studied. The objective of these systems is, observing correlated enrollment and authentication biometric sequences, to generate or convey as large as

  16. 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

  17. The need for international nursing diagnosis research and a theoretical framework.

    Science.gov (United States)

    Lunney, Margaret

    2008-01-01

    To describe the need for nursing diagnosis research and a theoretical framework for such research. A linguistics theory served as the foundation for the theoretical framework. Reasons for additional nursing diagnosis research are: (a) file names are needed for implementation of electronic health records, (b) international consensus is needed for an international classification, and (c) continuous changes occur in clinical practice. A theoretical framework used by the author is explained. Theoretical frameworks provide support for nursing diagnosis research. Linguistics theory served as an appropriate exemplar theory to support nursing research. Additional nursing diagnosis studies based upon a theoretical framework are needed and linguistics theory can provide an appropriate structure for this research.

  18. Theoretical nuclear physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The theoretical physics program in the Physics Division at ORNL involves research in both nuclear and atomic physics. In nuclear physics there is extensive activity in the fields of direct nuclear reactions with light- and heavy-ion projectiles, the structure of nuclei far from stability and at elevated temperatures, and the microscopic and macroscopic description of heavy-ion dynamics, including the behavior of nuclear molecules and supernuclei. New research efforts in relativistic nuclear collisions and in the study of quark-gluon plasma have continued to grow this year. The atomic theory program deals with a variety of ionization, multiple-vacancy production, and charge-exchange processes. Many of the problems are selected because of their relevance to the magnetic fusion energy program. In addition, there is a joint atomic-nuclear theory effort to study positron production during the collision of two high-Z numbers, i.e., U+U. A new Distinguished Scientist program, sponsored jointly by the University of Tennessee and ORNL, has been initiated. Among the first appointments is G.F. Bertsch in theoretical physics. As a result of this appointment, Bertsch and an associated group of four theorists split their time between UT and ORNL. In addition, the State of Tennessee has established a significant budget to support the visits of outstanding scientists to the Joint Institute for Heavy Ion Research at ORNL. This budget should permit a significant improvement in the visitor program at ORNL. Finally, the Laboratory awarded a Wigner post-doctoral Appointment to a theorist who will work in the theory group of the Physics Division

  19. Information theoretic quantification of diagnostic uncertainty.

    Science.gov (United States)

    Westover, M Brandon; Eiseman, Nathaniel A; Cash, Sydney S; Bianchi, Matt T

    2012-01-01

    Diagnostic test interpretation remains a challenge in clinical practice. Most physicians receive training in the use of Bayes' rule, which specifies how the sensitivity and specificity of a test for a given disease combine with the pre-test probability to quantify the change in disease probability incurred by a new test result. However, multiple studies demonstrate physicians' deficiencies in probabilistic reasoning, especially with unexpected test results. Information theory, a branch of probability theory dealing explicitly with the quantification of uncertainty, has been proposed as an alternative framework for diagnostic test interpretation, but is even less familiar to physicians. We have previously addressed one key challenge in the practical application of Bayes theorem: the handling of uncertainty in the critical first step of estimating the pre-test probability of disease. This essay aims to present the essential concepts of information theory to physicians in an accessible manner, and to extend previous work regarding uncertainty in pre-test probability estimation by placing this type of uncertainty within a principled information theoretic framework. We address several obstacles hindering physicians' application of information theoretic concepts to diagnostic test interpretation. These include issues of terminology (mathematical meanings of certain information theoretic terms differ from clinical or common parlance) as well as the underlying mathematical assumptions. Finally, we illustrate how, in information theoretic terms, one can understand the effect on diagnostic uncertainty of considering ranges instead of simple point estimates of pre-test probability.

  20. Theoretical Studies on Expressions of Condensed-Phase Photoionization Cross Section

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Wang Meishan; Wang Dehua; Qu Zhaojun

    2006-01-01

    A set of general expressions for photoionization cross sections of atoms or molecules embedded in a medium and a dielectric influence function are derived based on Maxwell's equations and the Beer-Lambert's law in this work. The applications are performed for the photoionization process of solid gold both in the Clausius-Mossotti (virtual cavity) model and the Glauber-Lewenstein (real cavity) model firstly. The results show that the present theoretical expressions of photoionization cross section can be used to describe the photoionization process of atoms in condensed matter properly.

  1. Department of Theoretical Physics - Overview

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    2002-01-01

    Full text: Research activity of the Department of Theoretical Physics concerns theoretical high energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and of relativistic heavy ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research yet the more formal problems are also considered. The detailed summary of the research projects and of the results obtained in various fields is given in the abstracts. Our Department successfully collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular, members of our Department participate in the EC network which allows for the mobility of researchers. Several members of our Department have also participated in the research projects funded by the State Committee for Scientific Research. Besides pure research, members of our Department are also involved in graduate and undergraduate teaching activity both at our Institute and at other academic institutions in Cracow. At present, eight students are working towards their Ph.D. degrees under the supervision of senior members of the Department. (author)

  2. Department of Theoretical Physics - Overview

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    2001-01-01

    Full text: Research activity of the Department of Theoretical Physics concerns theoretical high-energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and relativistic heavy-ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research yet more formal problems are also considered. A detailed summary of the research projects and of the results obtained in various field is given in the abstracts. Our Department actively collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular, members of our Department participate in the EC network, which stimulates the mobility of researchers. Several members of our Department also participated in the research projects funded by the Polish Committee for Scientific Research (KBN). Besides pure research, members of our Department are also involved in graduate and up graduate teaching activity at our Institute as well as at other academic institution in Cracow. At present nine students are working on their Ph.D. degrees under the supervision of senior members of the Department. (author)

  3. A Theoretical Framework for Association Studies in F2 Family Pools Using Allele Frequencies from Genotyping-By-Sequencing

    DEFF Research Database (Denmark)

    Janss, Luc L; Ashraf, Bilal H; Greve-Pedersen, Morten

    a sequencing approach to obtain Single Nucleotide Polymorphisms (SNPs) frequencies is considered here. In this work we develop the theoretical framework to perform association studies using allele frequencies from such F2 family pools. We show that expected allele frequencies in the F2 families will have...

  4. Theoretical Study on Regioselectivity of the Diels-Alder Reaction between 1,8-Dichloroanthracene and Acrolein.

    Science.gov (United States)

    Sultan, Mujeeb A; Karama, Usama; Almansour, Abdulrahman I; Soliman, Saied M

    2016-09-23

    A theoretical study of the regioselectivity of the Diels-Alder reaction between 1,8-dichloroanthracene and acrolein is performed using DFT at the B3LYP/6-31G(d,p) level of theory. The FMO analysis, global and local reactivity indices confirmed the reported experimental results. Potential energy surface analysis showed that the cycloadditions (CAs) favor the formation of the anti product. These results are in good agreement with the reported results obtained experimentally where the anti is the major product.

  5. Experimental and theoretical studies of cylindrical Hall thrusters

    International Nuclear Information System (INIS)

    Smirnov, Artem; Raitses, Yegeny; Fisch, Nathaniel J.

    2007-01-01

    The Hall thruster is a mature electric propulsion device that holds considerable promise in terms of the propellant saving potential. The annular design of the conventional Hall thruster, however, does not naturally scale to low power. The efficiency tends to be lower and the lifetime issues are more aggravated. Cylindrical geometry Hall thrusters have lower surface-to-volume ratio than conventional thrusters and, thus, seem to be more promising for scaling down. The cylindrical Hall thruster (CHT) is fundamentally different from the conventional design in the way the electrons are confined and the ion space charge is neutralized. The performances of both the large (9-cm channel diameter, 600-1000 W) and miniaturized (2.6-cm channel diameter, 50-300 W) CHTs are comparable with those of the state-of-the-art conventional (annular) design Hall thrusters of similar sizes. A comprehensive experimental and theoretical study of the CHT physics has been conducted, addressing the questions of electron cross-field transport, propellant ionization, plasma-wall interaction, and formation of the electron distribution function. Probe measurements in the harsh plasma environment of the microthruster were performed. Several interesting effects, such as the unusually high ionization efficiency and enhanced electron transport, were observed. Kinetic simulations suggest the existence of the strong fluctuation-enhanced electron diffusion and predict the non-Maxwellian shape of the electron distribution function. Through the acquired understanding of the new physics, ways for further optimization of this means for low-power space propulsion are suggested. Substantial flexibility in the magnetic field configuration of the CHT is the key tool in achieving the high-efficiency operation

  6. Theoretical Molecular Biophysics

    CERN Document Server

    Scherer, Philipp

    2010-01-01

    "Theoretical Molecular Biophysics" is an advanced study book for students, shortly before or after completing undergraduate studies, in physics, chemistry or biology. It provides the tools for an understanding of elementary processes in biology, such as photosynthesis on a molecular level. A basic knowledge in mechanics, electrostatics, quantum theory and statistical physics is desirable. The reader will be exposed to basic concepts in modern biophysics such as entropic forces, phase separation, potentials of mean force, proton and electron transfer, heterogeneous reactions coherent and incoherent energy transfer as well as molecular motors. Basic concepts such as phase transitions of biopolymers, electrostatics, protonation equilibria, ion transport, radiationless transitions as well as energy- and electron transfer are discussed within the frame of simple models.

  7. Contribution to the theoretical study of metallic systems containing rare earths: hyperfine interactions and exchange coupling

    International Nuclear Information System (INIS)

    Troper, A.

    1978-01-01

    A theoretical study involving rare earth impurities, which were embedded in transition metals (s-p or noble), from the point of view of the hyperfine interactions is presented. A model was created to describe a d-resonance (Anderson-Moriya) acting on a s-p conduction band which was strongly perturbed by a slater-koster potential, used to describe the rare earths which were diluted in matrices of transition elements. (author)

  8. A theoretical and mass spectrometry study of the fragmentation of mycosporine-like amino acids

    Science.gov (United States)

    Cardozo, Karina H. M.; Vessecchi, Ricardo; Carvalho, Valdemir M.; Pinto, Ernani; Gates, Paul J.; Colepicolo, Pio; Galembeck, Sérgio E.; Lopes, Norberto P.

    2008-06-01

    In the present study, the mycosporine-like amino acids (MAAs) were isolated from the marine red alga Gracilaria tenuistipitata and analysed by high-resolution accurate-mass sequential mass spectrometry (MSn). In addition to the proposed fragmentation mechanism based on the MSn analysis, it is clearly demonstrated that the elimination of mass 15 is a radical processes taking place at the methoxyl substituent of the double bond. This characteristic loss of a methyl radical was studied by theoretical calculations and the homolytic cleavage of the OC bond is suggested to be dependent on the bond weakening. The protonation site of the MAAs was indicated by analysis of the Fukui functions and the relative Gibbs energies of the several possible protonated forms.

  9. Actual and theoretical gas consumption in Dutch dwellings: What causes the differences?

    International Nuclear Information System (INIS)

    Majcen, Daša; Itard, Laure; Visscher, Henk

    2013-01-01

    Energy labels in buildings are awarded based on theoretical gas and electricity consumption based on dwelling's physical characteristics. Prior to this research, a large-scale study was conducted in The Netherlands comparing theoretical energy use with data on actual energy use revealing substantial discrepancies (Majcen et al., 2013). This study uses identical energy label data, supplemented with additional data sources in order to reveal how different parameters influence theoretical and actual consumptions gas and electricity. Analysis is conducted through descriptive statistics and regression analysis. Regression analysis explained far less of the variation in the actual consumption than in the theoretical and has shown that variables such as floor area, ownership type, salary and the value of the house, which predicted a high degree of change in actual gas consumption, were insignificant (ownership, salary, value) or had a minor impact on theoretical consumption (floor area). Since some possibly fundamental variables were unavailable for regression analysis, we also conducted a sensitivity study of theoretical gas consumption. It showed that average indoor temperature, ventilation rate and accuracy of U-value have a large influence on the theoretical gas consumption; whereas the number of occupants and internal heat load have a rather limited impact. - Highlights: • Floor area, ownership, salary and value predict the change in actual gas use well. • Mentioned variables are insignificant or have small impact on theoretical use. • Energy consumption of less energy efficient systems is overestimated. • Accurate model assumptions and inspections would reduce the discrepancies. • Big discrepancies stem from misassumption of temperature, heated floor area, U values

  10. A theoretical model of semi-elliptic surface crack growth

    Directory of Open Access Journals (Sweden)

    Shi Kaikai

    2014-06-01

    Full Text Available A theoretical model of semi-elliptic surface crack growth based on the low cycle strain damage accumulation near the crack tip along the cracking direction and the Newman–Raju formula is developed. The crack is regarded as a sharp notch with a small curvature radius and the process zone is assumed to be the size of cyclic plastic zone. The modified Hutchinson, Rice and Rosengren (HRR formulations are used in the presented study. Assuming that the shape of surface crack front is controlled by two critical points: the deepest point and the surface point. The theoretical model is applied to semi-elliptic surface cracked Al 7075-T6 alloy plate under cyclic loading, and five different initial crack shapes are discussed in present study. Good agreement between experimental and theoretical results is obtained.

  11. Phenomenological description of selected elementary chemical reaction mechanisms: An information-theoretic study

    International Nuclear Information System (INIS)

    Esquivel, R.O.; Flores-Gallegos, N.; Iuga, C.; Carrera, E.M.; Angulo, J.C.; Antolin, J.

    2010-01-01

    The information-theoretic description of the course of two elementary chemical reactions allows a phenomenological description of the chemical course of the hydrogenic abstraction and the S N 2 identity reactions by use of Shannon entropic measures in position and momentum spaces. The analyses reveal their synchronous/asynchronous mechanistic behavior.

  12. Theoretical study of the structure and reactivity of lanthanide and actinide based organometallic complexes

    International Nuclear Information System (INIS)

    Barros, N.

    2007-06-01

    In this PhD thesis, lanthanide and actinide based organometallic complexes are studied using quantum chemistry methods. In a first part, the catalytic properties of organo-lanthanide compounds are evaluated by studying two types of reactions: the catalytic hydro-functionalization of olefins and the polymerisation of polar monomers. The reaction mechanisms are theoretically determined and validated, and the influence of possible secondary non productive reactions is envisaged. A second part focuses on uranium-based complexes. Firstly, the electronic structure of uranium metallocenes is analysed. An analogy with the uranyl compounds is proposed. In a second chapter, two isoelectronic complexes of uranium IV are studied. After validating the use of DFT methods for describing the electronic structure and the reactivity of these compounds, it is shown that their reactivity difference can be related to a different nature of chemical bonding in these complexes. (author)

  13. Studying Economic Space: Synthesis of Balance and Game-Theoretic Methods of Modelling

    Directory of Open Access Journals (Sweden)

    Natalia Gennadyevna Zakharchenko

    2015-12-01

    Full Text Available The article introduces questions about development of models used to study economic space. The author proposes the model that combines balance and game-theoretic methods for estimating system effects of economic agents’ interactions in multi-level economic space. The model is applied to research interactions between economic agents that are spatially heterogeneous within the Russian Far East. In the model the economic space of region is considered in a territorial dimension (the first level of decomposing space and also in territorial and product dimensions (the second level of decomposing space. The paper shows the mechanism of system effects formation that exists in the economic space of region. The author estimates system effects, analyses the real allocation of these effects between economic agents and identifies three types of local industrial markets: with zero, positive and negative system effects

  14. EVOLUTION OF THEORETICAL AND METHODOLOGICAL FOUNDATIONS OF COMPARATIVE ECONOMICS

    OpenAIRE

    N. Grazhevska

    2014-01-01

    The article reveals the evolution stages of theoretical and methodological foundations of comparative economics. The author highlights algorithms of comparative analysis as well as theoretical and methodological limitations of four research programs of the new comparative economics. The article justifies the necessity of a comprehensive comparative study of the major trends and contradictions in the development of national economies in the era of globalization.

  15. EVOLUTION OF THEORETICAL AND METHODOLOGICAL FOUNDATIONS OF COMPARATIVE ECONOMICS

    Directory of Open Access Journals (Sweden)

    N. Grazhevska

    2014-12-01

    Full Text Available The article reveals the evolution stages of theoretical and methodological foundations of comparative economics. The author highlights algorithms of comparative analysis as well as theoretical and methodological limitations of four research programs of the new comparative economics. The article justifies the necessity of a comprehensive comparative study of the major trends and contradictions in the development of national economies in the era of globalization.

  16. Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT

    Directory of Open Access Journals (Sweden)

    Adib Ghaleb

    2017-12-01

    Full Text Available A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center Process (Domingo approach, HSAB principle (Gazquez and Mendez approach, and the activation energy calculations. The analysis of results shows that the reaction takes place along concerted asynchronous mechanism and the isomer meta is favored, in agreement with the experiment results. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1017 

  17. Theoretical Study on Regioselectivity of the Diels-Alder Reaction between 1,8-Dichloroanthracene and Acrolein

    Directory of Open Access Journals (Sweden)

    Mujeeb A. Sultan

    2016-09-01

    Full Text Available A theoretical study of the regioselectivity of the Diels-Alder reaction between 1,8-dichloroanthracene and acrolein is performed using DFT at the B3LYP/6-31G(d,p level of theory. The FMO analysis, global and local reactivity indices confirmed the reported experimental results. Potential energy surface analysis showed that the cycloadditions (CAs favor the formation of the anti product. These results are in good agreement with the reported results obtained experimentally where the anti is the major product.

  18. Game Theoretic Resolution of Water Conflicts

    Science.gov (United States)

    Tyagi, H.; Gosain, A. K.; Khosa, R.

    2017-12-01

    Water disputes are of multi-disciplinary nature and involve an array of natural, hydrological,social, political and economic issues. Operations Research based decision making methodshave been found to facilitate mathematical analysis of such multifaceted problems thatconsist of multiple stakeholders and their conflicting objectives. Game Theoretic techniqueslike Metagame and Hypergame Analysis can provide a framework for conceptualizing waterconflicts and envisaging their potential solutions. In the present research, firstly a Metagamemodel has been developed to identify range of plausible equilibrium outcomes for resolvingconflicts pertaining to water apportionments in a transboundary watercourse. Further, it hasbeen observed that the contenders often hide their strategies from other players to getfavorable water allocations. Consequently, there are widespread misinterpretations about thetactics of the competitors and contenders have to formulate their strategies entirely based ontheir perception about others. Accordingly, a Hypergame study has also been conducted tomodel the probable misperceptions that may exist amongst the river riparians. Thus, thecurrent study assesses the efficacy of Game Theoretic techniques as possible redressalmechanism for water conflicts.

  19. Eighteenth annual West Coast theoretical chemistry conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    Abstracts are presented from the eighteenth annual west coast theoretical chemistry conference. Topics include molecular simulations; quasiclassical simulations of reactions; photodissociation reactions; molecular dynamics;interface studies; electronic structure; and semiclassical methods of reactive systems.

  20. Production of electroweak bosons at hadron colliders: theoretical aspects

    CERN Document Server

    Mangano, Michelangelo L.

    2016-01-01

    Since the W and Z discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard Model.

  1. Theoretical Studies on Electronic States of Rh-C60. Possibility of a Room-temperature Organic Ferromagnet

    Directory of Open Access Journals (Sweden)

    K. Yamaguchi

    2004-08-01

    Full Text Available A possible mechanism for a ferromagnetic interaction in the rhombic (Rh formof C60 (Rh-C60 is suggested on the basis of theoretical studies in relation to cage distortionof the C60 unit in the polymerized 2D-plane. Band structure calculations on Rh-C60 showthat cage distortion leads to competition between diamagnetic and ferromagnetic states,which give rise to the possibility of thermally populating the ferromagnetic state.

  2. Theoretical and experimental study on broadband terahertz atmospheric transmission characteristics

    International Nuclear Information System (INIS)

    Guo Shi-Bei; Zhong Kai; Wang Mao-Rong; Liu Chu; Xu De-Gang; Yao Jian-Quan; Xiao Yong; Wang Wen-Peng

    2017-01-01

    Broadband terahertz (THz) atmospheric transmission characteristics from 0 to 8 THz are theoretically simulated based on a standard Van Vleck–Weisskopf line shape, considering 1696 water absorption lines and 298 oxygen absorption lines. The influences of humidity, temperature, and pressure on the THz atmospheric absorption are analyzed and experimentally verified with a Fourier transform infrared spectrometer (FTIR) system, showing good consistency. The investigation and evaluation on high-frequency atmospheric windows are good supplements to existing data in the low-frequency range and lay the foundation for aircraft-based high-altitude applications of THz communication and radar. (paper)

  3. Theoretical study of ferroelectric nanoparticles using phase reconstructed electron microscopy

    Science.gov (United States)

    Phatak, C.; Petford-Long, A. K.; Beleggia, M.; De Graef, M.

    2014-06-01

    Ferroelectric nanostructures are important for a variety of applications in electronic and electro-optical devices, including nonvolatile memories and thin-film capacitors. These applications involve stability and switching of polarization using external stimuli, such as electric fields. We present a theoretical model describing how the shape of a nanoparticle affects its polarization in the absence of screening charges, and quantify the electron-optical phase shift for detecting ferroelectric signals with phase-sensitive techniques in a transmission electron microscope. We provide an example phase shift computation for a uniformly polarized prolate ellipsoid with varying aspect ratio in the absence of screening charges.

  4. Entropic and Electrostatic Effects on the Folding Free Energy of a Surface-Attached Biomolecule: An Experimental and Theoretical Study

    Science.gov (United States)

    Watkins, Herschel M.; Vallée-Bélisle, Alexis; Ricci, Francesco; Makarov, Dmitrii E.; Plaxco, Kevin W.

    2012-01-01

    Surface-tethered biomolecules play key roles in many biological processes and biotechnologies. However, while the physical consequences of such surface attachment have seen significant theoretical study, to date this issue has seen relatively little experimental investigation. In response we present here a quantitative experimental and theoretical study of the extent to which attachment to a charged –but otherwise apparently inert– surface alters the folding free energy of a simple biomolecule. Specifically, we have measured the folding free energy of a DNA stem loop both in solution and when site-specifically attached to a negatively charged, hydroxyl-alkane-coated gold surface. We find that, whereas surface attachment is destabilizing at low ionic strength it becomes stabilizing at ionic strengths above ~130 mM. This behavior presumably reflects two competing mechanisms: excluded volume effects, which stabilize the folded conformation by reducing the entropy of the unfolded state, and electrostatics, which, at lower ionic strengths, destabilizes the more compact folded state via repulsion from the negatively charged surface. To test this hypothesis we have employed existing theories of the electrostatics of surface-bound polyelectrolytes and the entropy of surface-bound polymers to model both effects. Despite lacking any fitted parameters, these theoretical models quantitatively fit our experimental results, suggesting that, for this system, current knowledge of both surface electrostatics and excluded volume effects is reasonably complete and accurate. PMID:22239220

  5. A theoretical perspective on road safety communication campaigns.

    Science.gov (United States)

    Elvik, Rune

    2016-12-01

    This paper proposes a theoretical perspective on road safety communication campaigns, which may help in identifying the conditions under which such campaigns can be effective. The paper proposes that, from a theoretical point of view, it is reasonable to assume that road user behaviour is, by and large, subjectively rational. This means that road users are assumed to behave the way they think is best. If this assumption is accepted, the best theoretical prediction is that road safety campaigns consisting of persuasive messages only will have no effect on road user behaviour and accordingly no effect on accidents. This theoretical prediction is not supported by meta-analyses of studies that have evaluated the effects of road safety communication campaigns. These analyses conclude that, on the average, such campaigns are associated with an accident reduction. The paper discusses whether this finding can be explained theoretically. The discussion relies on the distinction made by many modern theorists between bounded and perfect rationality. Road user behaviour is characterised by bounded rationality. Hence, if road users can gain insight into the bounds of their rationality, so that they see advantages to themselves of changing behaviour, they are likely to do so. It is, however, largely unknown whether such a mechanism explains why some road safety communication campaigns have been found to be more effective than others. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Orlistat interaction with sibutramine and carnitine. A physicochemical and theoretical study

    Science.gov (United States)

    Nicolás-Vázquez, Inés; Hinojosa Torres, Jaime; Cruz Borbolla, Julián; Miranda Ruvalcaba, René; Aceves-Hernández, Juan Manuel

    2014-03-01

    Chemical degradation of orlistat, (ORT) after melting and reaction of decomposition byproducts with sibutramine, SIB was studied. Interactions between the active pharmaceutical ingredients by using thermal analysis, TA, methods and other experimental techniques such as PXRD, IR and UV-vis spectroscopies were carried out to investigate chemical reactions between components. It was found that orlistat melts with decomposition and byproducts quickly affect sibutramine molecule and then reacting also with carnitine, CRN when the three active pharmaceutical ingredients (API's) are mixed. However ORT byproducts do not react when ORT is mixed only with carnitine. It was found that compounds containing chlorine atoms react easily with orlistat when the temperature increases up to its melting point. Some reaction mechanisms of orlistat decomposition are proposed, the fragments in the mechanisms were found in the corresponding mass spectra. Results obtained indicate that special studies should be carried out in the formulation stage before the final composition of a poly-pill could be established. Similar results are commonly found for compounds very prone to react in presence of water, light and/or temperature. In order to explain the reactivity of orlistat with sibutramine and carnitine, theoretical calculations were carried out and the results are in agreement with the experimental results.

  7. Theoretical Study of Energy Levels and Transition Probabilities of Boron Atom

    Science.gov (United States)

    Tian Yi, Zhang; Neng Wu, Zheng

    2009-08-01

    Full Text PDF Though the electrons configuration for boron atom is simple and boron atom has long been of interest for many researchers, the theoretical studies for properties of BI are not systematic, there are only few results reported on energy levels of high excited states of boron, and transition measurements are generally restricted to transitions involving ground states and low excited states without considering fine structure effects, provided only multiplet results, values for transitions between high excited states are seldom performed. In this article, by using the scheme of the weakest bound electron potential model theory calculations for energy levels of five series are performed and with the same method we give the transition probabilities between excited states with considering fine structure effects. The comprehensive set of calculations attempted in this paper could be of some value to workers in the field because of the lack of published calculations for the BI systems. The perturbations coming from foreign perturbers are taken into account in studying the energy levels. Good agreement between our results and the accepted values taken from NIST has been obtained. We also reported some values of energy levels and transition probabilities not existing on the NIST data bases.

  8. A theoretical study on the reaction of diazocompounds with C{sub 70} fullerene

    Energy Technology Data Exchange (ETDEWEB)

    Rostami, Zahra, E-mail: zahrarostami.pnu@gmail.com [Department of Chemistry, Payame Noor University (PNU), P. O. Box, 19395-3697 Tehran (Iran, Islamic Republic of); Hosseini, Javad [Department of Chemistry, Tuyserkan Branch, Islamic Azad University, Tuyserkan (Iran, Islamic Republic of); Panahyab, Ataollah [Young Researchers and Elites Club, Central Tehran Branch, Islamic Azad University, Tahran (Iran, Islamic Republic of)

    2017-02-01

    Highlights: • Functionalization of a C{sub 70} with diazocompounds was studied by DFT. • Stability [5,6]-fulleroids shows the same trend to that observed experimentally. • The reaction energy is in the range of −23.3 to −37.7 kcal/mol. • Orbital analysis explains the experimentally observed UV–vis spectrums. • Theoretical {sup 1}H NMR results are in excellent agreement with the experimental. - Abstract: Using density functional theory calculations, we investigated the chemical functionalization of a C{sub 70} fullerene with diazocompounds which has been reported experimentally. The results indicate that the [5,6]-bond of the apex of C{sub 70} is more reactive than the equatorial bonds toward the cycloaddition of the diazocompounds. The energetic stability of phenyl C{sub 71} butyric acid methyl ester (PCBM)-type [5,6]-fulleroids (products) shows the same trend (1 > 2 > 3 > 4) to that observed experimentally. The reaction energy for different isomers of [5,6]-fulleroids is in the range of −23.3 to −37.7 kcal/mol. Our frontier molecular orbital analysis explains the experimentally observed UV–vis spectrums and confirmed the formation of [5,6]-fulleroids rather than [6,6]-methanofullerenes. The electron–hole pair binding energy for C{sub 70} is calculated to be about 0.6 to 0.9 eV. Theoretical {sup 1}H-nuclear magnetic resonance (NMR), in good agreement with the corresponding experimental data, was used to more investigate the structure of the most stable complex.

  9. Sampling from a system-theoretic viewpoint

    NARCIS (Netherlands)

    Meinsma, Gjerrit; Mirkin, Leonid

    2009-01-01

    This paper studies a system-theoretic approach to the problem of reconstructing an analog signal from its samples. The idea, borrowed from earlier treatments in the control literature, is to address the problem as a hybrid model-matching problem in which performance is measured by system norms. The

  10. Nonlinear optical properties of chiral polyesters: a joint experimental and theoretical study

    Science.gov (United States)

    Biju, Philip; Sreekumar, K.

    2003-10-01

    A series of polyesters containing donor-acceptor π-conjugated polar segments (4,4'-azobenzene dicarbonyl chloride) and chiral building units [L(+)-diethyl tartrate] in the main chain were synthesized and characterized by spectroscopic (IR, UV-Vis, 1H NMR, 13C NMR), thermal (TG/DTG, DSC), and optical (refractive index, optical rotation techniques). Chiral order was induced with a preferred helical sense to attain noncentrosymmetric ordering of dipoles (polar order) in macroscopic dimensions by chemical synthesis (chemical poling). A comprehensive attempt has been made to correlate the polar order of the polymer chains with the chiral order arising out of a preferred helical sense of the chains. This has been achieved by adopting four different theoretical models and comparing the results with the experimentally observed values of the second order polarizability tensor β. The models used are (1) Logarithmic Law of Mixing (LLM), (2) the Extended Boundary Condition Method (EBCM), (3) The Random Field Ising Model (RFIM) and (4) Semiempirical Computational Model (SCM). The results of the theoretical predictions are compared with the experimentally determined values of β.

  11. Theoretical studies of potential energy surfaces and computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, R. [Argonne National Laboratory, IL (United States)

    1993-12-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  12. Theoretical study of disorder in Ti-substituted La2Zr2O7

    International Nuclear Information System (INIS)

    Chartier, Alain; Meis, Constantin; Weber, William J.; Corrales, L. Rene

    2002-01-01

    Pyrochlores have the striking feature that their radiation resistance is highly dependent on their composition. In this work, the propensity of a pyrochlore to transform to a cation-disordered structure and the influence of titanium ions is ascertained from the mechanisms of defect formation. A detailed study of defect formation and migration activation energies in Ti-substituted La 2 Zr 2 O 7 is carried out by modern theoretical computational methods that include the use of a classical interatomic potential with a modified shell model to capture the effects of local charge transfer. The results show that La 2 Zr 2 O 7 has a tendency towards cation disorder, whereas, substitution of Zr with Ti makes this tendency energetically less favorable

  13. Theoretical study of the porosity effects on the shock response of graphitic materials

    Directory of Open Access Journals (Sweden)

    Pineau Nicolas

    2015-01-01

    Full Text Available In this paper we present a theoretical study of the shock compression of porous graphite by means of combined Monte Carlo and molecular dynamics simulations using the LCBOPII potential. The results show that the Hugoniostat methods can be used with “pole” properties calculated from porous models to reproduce the experimental Hugoniot of pure graphite and diamond with good accuracy. The computed shock temperatures show a sharp increase for weak shocks which we analyze as the heating associated with the closure of the initial porosity. After this initial phase, the temperature increases with shock intensity at a rate comparable to monocrystalline graphite and diamond. These simulations data can be exploited in view to build a full equation of state for use in hydrodynamic simulations.

  14. A theoretical study of interaction effects on the remanence curves of particulate dispersions

    Science.gov (United States)

    Fearon, M.; Chantrell, R. W.; Wohlfarth, E. P.

    1990-05-01

    The remanence curves of strongly interacting fine-particle systems are investigated theoretically. It is shown that the Henkel plot of the dc demagnetisation remanence vs. the isothermal remanence is a useful representation of interactions. The form of the plot is found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is also investigated. The results are consistent with a previous experimental study. Finally, the effect of interactions on the Switching Field Distribution are investigated.

  15. Supplement to final report for ''Theoretical studies in tokamaks''

    International Nuclear Information System (INIS)

    McBride, J.B.

    1992-07-01

    In a previous report we summarized the results obtained for Task I of Contract Number AC03-88ER53270 for the two-year period of performance of the work supported by the contract. That report constituted the final report for Task 1. Since then, the contract was extended and the funding for Task I was incremented with $35K of new funds. The purpose for incrementing the contract was to begin a collaboration with the PBX-M group at Princeton Plasma Physics Laboratory (PPPL) in the area of ion Bernstein wave (IBW) effects in the PBX-M experiment. This report summarizes the initial results of that collaboration obtained under the incremental continuation funding. In the intervening period, experimental and theoretical program directions changed so that no further funds were committed to Task 1

  16. A theoretical model on surface electronic behavior: Strain effect

    International Nuclear Information System (INIS)

    Qin, W.G.; Shaw, D.

    2009-01-01

    Deformation from mechanical loading can affect surface electronic behavior. Surface deformation and electronic behavior can be quantitatively expressed using strain and work function, respectively, and their experimental relationship can be readily determined using the Kelvin probing technique. However, the theoretical correlation between work function and strain has been unclear. This study reports our theoretical exploration, for the first time, of the effect of strain on work function. We propose a simple electrostatic action model by considering the effect of a dislocation on work function of a one-dimensional lattice and further extend this model to the complex conditions for the effect of dislocation density. Based on this model, we established successfully a theoretical correlation between work function and strain.

  17. Experimental and theoretical studies of the VUV emission and absorption spectra of H2, HD and D2 molecules

    International Nuclear Information System (INIS)

    Roudjane, M.

    2007-12-01

    The aim of this thesis is to carry out an experimental study of the absorption and emission spectra of the D 2 and HD isotopes, with high resolution, in the VUV domain and to supplement it by a theoretical study of the excited electronic states involved in the observed transitions. The emission spectra of HD and D 2 are produced by Penning discharge source operating under low pressure and are recorded in the spectral range 78 - 170 nm. The recorded spectra contains more than 20.000 lines. The analysis of the spectrum consists in identifying and assigning the lines to the electronic transitions between energy levels of the molecule. The present analysis is based on our theoretical calculations of the ro-vibrational energy levels of the excited electronic states and the transition probabilities from these states towards the energy levels of the fundamental state. The theoretical results are obtained by resolving the coupled equations between the excited electronic states B 1 Σ u 1 , B' 1 Σ u 1 , C 1 Π u 1 and D 1 Π u 1 , taking into account the nonadiabatic couplings between these states, and they are obtained in the adiabatic approximation for the excited electronic states B''B-bar 1 Σ u + , D' 1 Π u 1 and D'' 1 Π u 1 . The equations are resolved using a modern method based on the discretization variables representation method. In addition, we have carried out a study of the absorption spectra of the HD and D 2 molecules

  18. Research in theoretical nuclear physics

    International Nuclear Information System (INIS)

    Udagawa, T.

    1993-11-01

    This report describes the accomplishments in basic research in nuclear physics carried out by the theoretical nuclear physics group in the Department of Physics at the University of Texas at Austin, during the period of November 1, 1992 to October 31, 1993. The work done covers three separate areas, low-energy nuclear reactions, intermediate energy physics, and nuclear structure studies. Although the subjects are thus spread among different areas, they are based on two techniques developed in previous years. These techniques are a powerful method for continuum-random-phase-approximation (CRPA) calculations of nuclear response and the breakup-fusion (BF) approach to incomplete fusion reactions, which calculation on a single footing of various incomplete fusion reaction cross sections within the framework of direct reaction theories. The approach was developed as a part of a more general program for establishing an approach to describing all different types of nuclear reactions, i.e., complete fusion, incomplete fusion and direct reactions, in a systematic way based on single theoretical framework

  19. A theoretical study of hot plasma spheroids in the presence of low-frequency electromagnetic waves

    Science.gov (United States)

    Ahmadizadeh, Y.; Jazi, B.; Barjesteh, S.

    2016-07-01

    While taking into account thermal motion of electrons, scattering of electromagnetic waves with low frequency from hot plasma spheroids is investigated. In this theoretical research, ions are heavy to respond to electromagnetic fluctuations. The solution of scalar wave equation in spheroidal coordinates for electric potential inside the plasma spheroids are obtained. The variations of resonance frequencies vs. Debye length are studied and consistency between the obtained results in this paper and the results for the well-known plasma objects such as plasma column and spherical plasma have been proved.

  20. Atomic imaging by x-ray-fluorescence holography and electron-emission holography: A comparative theoretical study

    International Nuclear Information System (INIS)

    Len, P.M.; Thevuthasan, S.; Fadley, C.S.; Kaduwela, A.P.; Van Hove, M.A.

    1994-01-01

    We consider from a theoretical viewpoint the direct imaging of atoms at and near the surfaces of solids by both x-ray-fluorescence holography (XFH) and electron-emission holography (EEH). The more ideal nature of x-ray scattering makes XFH images superior to those in single-energy EEH. The overlap of real and twin features for pairs of atoms at ±a can cause their XFH or EEH atomic images to cancel for certain combinations of wave vector and |a|. The relative merits of XFH and EEH for structure studies are considered

  1. Complexation of Eu3+ with a macrocyclic lactam receptor: Experimental and theoretical study

    Czech Academy of Sciences Publication Activity Database

    Makrlík, E.; Záliš, Stanislav; Sedláková, Zdeňka; Vaňura, P.

    2013-01-01

    Roč. 1038, APR 2013 (2013), s. 216-219 ISSN 0022-2860 Institutional support: RVO:61388955 ; RVO:61389013 Keywords : europium * macrocyclic lactam receptor * complexation Subject RIV: CF - Physical ; Theoretical Chemistry; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 1.599, year: 2013

  2. The theoretical study of full spectrum analysis method for airborne gamma-ray spectrometric data

    International Nuclear Information System (INIS)

    Ni Weichong

    2011-01-01

    Spectra of airborne gamma-ray spectrometry was found to be the synthesis of spectral components of radioelement sources by analyzing the constitution of radioactive sources for airborne gamma-ray spectrometric survey and establishing the models of gamma-ray measurement. The mathematical equation for analysising airborne gamma-ray full spectrometric data can be expressed into matrix and related expansions were developed for the mineral resources exploration, environmental radiation measurement, nuclear emergency monitoring, and so on. Theoretical study showed that the atmospheric radon could be directly computed by airborne gamma-ray spectrometric data with full spectrum analysis without the use of the accessional upward-looking detectors. (authors)

  3. Experimental study and theoretical simulation of the cross hardening effect in shape memory alloys

    Science.gov (United States)

    Movchan, A. A.; Sil'chenko, A. L.; Kazarina, S. A.

    2017-10-01

    The shapes and the relative position of martensitic inelasticity and forward transformation diagrams are experimentally studied. The strain dependences of the stress in loading under martensitic inelasticity conditions after an experiment on the accumulation of the forward transformation-induced strain at a constant or variable stress are investigated on titanium nickelide samples. It is found that the hardening of the martensite part of the representative volume of a shape memory alloy (titanium nickelide) after forward transformation under a nonmonotonically changing stress can be nonuniform. The cross hardening phenomenon is theoretically described in terms of the model of nonlinear deformation of a shape memory alloy during phase and structural transformations.

  4. A theoretical study of exciton energy levels in laterally coupled quantum dots

    International Nuclear Information System (INIS)

    Barticevic, Z; Pacheco, M; Duque, C A; Oliveira, L E

    2009-01-01

    A theoretical study of the electronic and optical properties of laterally coupled quantum dots, under applied magnetic fields perpendicular to the plane of the dots, is presented. The exciton energy levels of such laterally coupled quantum-dot systems, together with the corresponding wavefunctions and eigenvalues, are obtained in the effective-mass approximation by using an extended variational approach in which the magnetoexciton states are simultaneously obtained. One achieves the expected limits of one single quantum dot, when the distance between the dots is zero, and of two uncoupled quantum dots, when the distance between the dots is large enough. Moreover, present calculations-with appropriate structural dimensions of the two-dot system-are shown to be in agreement with measurements in self-assembled laterally aligned GaAs quantum-dot pairs and naturally/accidentally occurring coupled quantum dots in GaAs/GaAlAs quantum wells.

  5. Inhibition of mild steel corrosion in acid solution by Pheniramine drug: Experimental and theoretical study

    International Nuclear Information System (INIS)

    Ahamad, Ishtiaque; Prasad, Rajendra; Quraishi, M.A.

    2010-01-01

    Inhibition of mild steel corrosion in 1 M HCl solution by Pheniramine drug was studied using weight loss, electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization measurements. The values of activation energy (E a ) and different thermodynamic parameters such as adsorption equilibrium constant (K ads ), free energy of adsorption (ΔG ads o ), adsorption enthalpy (ΔH ads o ) and adsorption entropy (ΔS ads o ) were calculated and discussed. The adsorption process of studied drug on mild steel surface obeys the Langmuir adsorption isotherm. Potentiodynamic polarization measurements showed that Pheniramine is mixed-type inhibitor. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  6. Theoretical study on photon-phonon coupling at (001)-(2 x 1) surfaces of Ge and {alpha}-Sn

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Sanchez, F.L. [Escuela de Ciencias, Universidad Autonoma ' ' Benito Juarez' ' de Oaxaca, Av. Universidad S/N, Ex-Hacienda de Cinco Senores, Ciudad Universitaria, Oaxaca de Juarez, Oax., 68120 (Mexico); Perez-Rodriguez, F. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apdo. Post. J-48, Puebla, Pue. 72570 (Mexico)

    2011-06-15

    We present a study of the far-infrared reflectance anisotropy spectra for (001) surfaces of Ge and {alpha}-Sn in the (2 x 1) asymmetric dimer geometry, which exhibit a resonance structure associated with the excitation of surface phonon modes. We have employed a theoretical formalism, based on the adiabatic bond-charge model (ABCM), for computing the far-infrared reflectance anisotropy spectra. In comparison with previous theoretical results for silicon and diamond surfaces, the resonance structure in the reflectance anisotropy spectrum for Ge(001)-(2 x 1) turns out to be similar to that observed in the spectrum for the Si(001)-(2 x 1) surface, whereas the spectrum for {alpha}-Sn(001)-(2 x 1) surface is noticeably different from the others. We have established a trend of far-infrared reflectance anisotropy spectra for IV(001) surfaces: the weaker dimer strength, the stronger resonances of low-frequency surface phonons. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Theoretical and empirical bases for dialect-neutral language assessment: contributions from theoretical and applied linguistics to communication disorders.

    Science.gov (United States)

    Pearson, Barbara Zurer

    2004-02-01

    Three avenues of theoretical research provide insights for discovering abstract properties of language that are subject to disorder and amenable to assessment: (1) the study of universal grammar and its acquisition; (2) descriptions of African American English (AAE) Syntax, Semantics, and Phonology within theoretical linguistics; and (3) the study of specific language impairment (SLI) cross-linguistically. Abstract linguistic concepts were translated into a set of assessment protocols that were used to establish normative data on language acquisition (developmental milestones) in typically developing AAE children ages 4 to 9 years. Testing AAE-speaking language impaired (LI) children and both typically developing (TD) and LI Mainstream American English (MAE)-learning children on these same measures provided the data to select assessments for which (1) TD MAE and AAE children performed the same, and (2) TD performance was reliably different from LI performance in both dialect groups.

  8. Theoretical issues in PDF determination and associated uncertainties

    CERN Document Server

    Ball, Richard D.; Del Debbio, Luigi; Forte, Stefano; Guffanti, Alberto; Rojo, Juan; Ubiali, Maria

    2013-01-01

    We study several sources of theoretical uncertainty in the determination of parton distributions (PDFs) which may affect current PDF sets used for precision physics at the Large Hadron Collider, and explain discrepancies between them. We consider in particular the use of fixed-flavor versus variable-flavor number renormalization schemes, higher twist corrections, and nuclear corrections. We perform our study in the framework of the NNPDF2.3 global PDF determination, by quantifying in each case the impact of different theoretical assumptions on the output PDFs. We also study in each case the implications for benchmark cross sections at the LHC. We find that the impact in a global fit of a fixed-flavor number scheme is substantial, the impact of higher twists is negligible, and the impact of nuclear corrections is moderate and circumscribed.

  9. Thermalization and prethermalization in isolated quantum systems: a theoretical overview

    Science.gov (United States)

    Mori, Takashi; Ikeda, Tatsuhiko N.; Kaminishi, Eriko; Ueda, Masahito

    2018-06-01

    The approach to thermal equilibrium, or thermalization, in isolated quantum systems is among the most fundamental problems in statistical physics. Recent theoretical studies have revealed that thermalization in isolated quantum systems has several remarkable features, which emerge from quantum entanglement and are quite distinct from those in classical systems. Experimentally, well isolated and highly controllable ultracold quantum gases offer an ideal testbed to study the nonequilibrium dynamics in isolated quantum systems, promoting intensive recent theoretical endeavors on this fundamental subject. Besides thermalization, many isolated quantum systems show intriguing behavior in relaxation processes, especially prethermalization. Prethermalization occurs when there is a clear separation of relevant time scales and has several different physical origins depending on individual systems. In this review, we overview theoretical approaches to the problems of thermalization and prethermalization.

  10. Theoretical study of evaporation heat transfer in horizontal microfin tubes: stratified flow model

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H; Wang, Y S [Kyushu Univ., Inst. for Materials Chemistry and Engineering, Kasuga, Fukuoka (Japan)

    2004-08-01

    The stratified flow model of evaporation heat transfer in helically grooved, horizontal microfin tubes has been developed. The profile of stratified liquid was determined by a theoretical model previously developed for condensation in horizontal microfin tubes. For the region above the stratified liquid, the meniscus profile in the groove between adjacent fins was determined by a force balance between the gravity and surface tension forces. The thin film evaporation model was applied to predict heat transfer in the thin film region of the meniscus. Heat transfer through the stratified liquid was estimated by using an empirical correlation proposed by Mori et al. The theoretical predictions of the circumferential average heat transfer coefficient were compared with available experimental data for four tubes and three refrigerants. A good agreement was obtained for the region of Fr{sub 0}<2.5 as long as partial dry out of tube surface did not occur. (Author)

  11. A Theoretical Study of the Outer Layers of Eight Kepler F-stars: The Relevance of Ionization Processes

    Science.gov (United States)

    Brito, Ana; Lopes, Ilídio

    2017-07-01

    We have analyzed the theoretical model envelopes of eight Kepler F-stars by computing the phase shift of the acoustic waves, α (ω ), and its related function, β (ω ). The latter is shown to be a powerful probe of the external stellar layers since it is particularly sensitive to the partial ionization zones located in these upper layers. We found that these theoretical envelopes can be organized into two groups, each of which is characterized by a distinct β (ω ) shape that we show to reflect the differences related to the magnitudes of ionization processes. Since β (ω ) can also be determined from the experimental frequencies, we compared our theoretical results with the observable β (ω ). Using the function β (ω ), and with the purpose of quantifying the magnitude of the ionization processes occurring in the outer layers of these stars, we define two indexes, {{Δ }}{β }1 and {{Δ }}{β }2. These indexes allow us to connect the microphysics of the interior of the star with macroscopic observable characteristics. Motivated by the distinct magnetic activity behaviors of F-stars, we studied the relation between the star’s rotation period and these indexes. We found a trend, in the form of a power-law dependence, that favors the idea that ionization is acting as an underlying mechanism, which is crucial for understanding the relation between rotation and magnetism and even observational features such as the Kraft break.

  12. Visual summation in night-flying sweat bees: a theoretical study.

    Science.gov (United States)

    Theobald, Jamie Carroll; Greiner, Birgit; Wcislo, William T; Warrant, Eric J

    2006-07-01

    Bees are predominantly diurnal; only a few groups fly at night. An evolutionary limitation that bees must overcome to inhabit dim environments is their eye type: bees possess apposition compound eyes, which are poorly suited to vision in dim light. Here, we theoretically examine how nocturnal bees Megalopta genalis fly at light levels usually reserved for insects bearing more sensitive superposition eyes. We find that neural summation should greatly increase M. genalis's visual reliability. Predicted spatial summation closely matches the morphology of laminal neurons believed to mediate such summation. Improved reliability costs acuity, but dark adapted bees already suffer optical blurring, and summation further degrades vision only slightly.

  13. Study of the hydroxyl radical: Experimental advances in microwave spectroscopy, theoretical model and astrophysical consequences

    International Nuclear Information System (INIS)

    Destombes, Jean-Luc

    1978-01-01

    This research thesis mainly addresses the experimental and theoretical study of the hydroxyl radical, and the consequences of the obtained results in astrophysics which are studied with a model of pumping by the far infrared. After a recall of notions related to microwave spectroscopy and to molecular radio-astronomy, the author more particularly discusses different aspects of microwave spectroscopy in the interstellar environment and in laboratory. He also reviews different types of spectrometers for unsteady molecules. In the second part, he addresses issues related to the hydroxyl radical (OH): presentation of spectrometers, study of the reaction environment, study of the radical microwave spectrum, identification of transitions by frequency measurements. In the last parts, the author addresses some aspects of interstellar OH masers, and reports the application of some results to simple models of pumping by the far infra red

  14. Theoretical clarity is not “Manicheanism”

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2011-01-01

    It is argued that in order to establish a new theoretical approach to information science it is necessary to express disagreement with some established views. The “social turn” in information science is not just exemplified in relation to the works of Marcia Bates but in relation to many different...... researchers in the field. Therefore it should not be taken personally, and the debate should focus on the substance. Marcia Bates has contributed considerably to information science. In spite of this some of her theoretical points of departure may be challenged. It is important to seek theoretical clarity...... and this may involve a degree of schematic confrontation that should not be confused with theoretical one-sidedness, “Manicheanism” or lack of respect....

  15. Set-Theoretic Approach to Maturity Models

    DEFF Research Database (Denmark)

    Lasrado, Lester Allan

    Despite being widely accepted and applied, maturity models in Information Systems (IS) have been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. This PhD thesis focuses on addressing...... these criticisms by incorporating recent developments in configuration theory, in particular application of set-theoretic approaches. The aim is to show the potential of employing a set-theoretic approach for maturity model research and empirically demonstrating equifinal paths to maturity. Specifically...... methodological guidelines consisting of detailed procedures to systematically apply set theoretic approaches for maturity model research and provides demonstrations of it application on three datasets. The thesis is a collection of six research papers that are written in a sequential manner. The first paper...

  16. Theoretical studies on lattice-oriented growth of single-walled carbon nanotubes on sapphire

    Science.gov (United States)

    Li, Zhengwei; Meng, Xianhong; Xiao, Jianliang

    2017-09-01

    Due to their excellent mechanical and electrical properties, single-walled carbon nanotubes (SWNTs) can find broad applications in many areas, such as field-effect transistors, logic circuits, sensors and flexible electronics. High-density, horizontally aligned arrays of SWNTs are essential for high performance electronics. Many experimental studies have demonstrated that chemical vapor deposition growth of nanotubes on crystalline substrates such as sapphire offers a promising route to achieve such dense, perfectly aligned arrays. In this work, a theoretical study is performed to quantitatively understand the van der Waals interactions between SWNTs and sapphire substrates. The energetically preferred alignment directions of SWNTs on A-, R- and M-planes and the random alignment on the C-plane predicted by this study are all in good agreement with experiments. It is also shown that smaller SWNTs have better alignment than larger SWNTs due to their stronger interaction with sapphire substrate. The strong vdW interactions along preferred alignment directions can be intuitively explained by the nanoscale ‘grooves’ formed by atomic lattice structures on the surface of sapphire. This study provides important insights to the controlled growth of nanotubes and potentially other nanomaterials.

  17. Experimental and theoretical study on field emission properties of zinc oxide nanoparticles decorated carbon nanotubes

    Science.gov (United States)

    Li, Xin; Zhou, Wei-Man; Liu, Wei-Hua; Wang, Xiao-Li

    2015-05-01

    Field emission properties of zinc oxide (ZnO) nanoparticles (NPs) decorated carbon nanotubes (CNTs) are investigated experimentally and theoretically. CNTs are in situ decorated with ZnO NPs during the growth process by chemical vapor deposition using a carbon source from the iron phthalocyanine pyrolysis. The experimental field emission test shows that the ZnO NP decoration significantly improves the emission current from 50 μA to 275 μA at 550 V and the reduced threshold voltage from 450 V to 350 V. The field emission mechanism of ZnO NPs on CNTs is theoretically studied by the density functional theory (DFT) combined with the Penn-Plummer method. The ZnO NPs reconstruct the ZnO-CNT structure and pull down the surface barrier of the entire emitter system to 0.49 eV so as to reduce the threshold electric field. The simulation results suggest that the presence of ZnO NPs would increase the LDOS near the Fermi level and increase the emission current. The calculation results are consistent with the experiment results. Project supported by the National Natural Science Foundation of China (Grant Nos. 91123018, 61172040, and 61172041) and the Natural Science Foundation of Shaanxi Province, China (Grant No. 2014JM7277).

  18. Theoretical study of turbulent channel flow - Bulk properties, pressure fluctuations, and propagation of electromagnetic waves

    Science.gov (United States)

    Canuto, V. M.; Hartke, G. J.; Battaglia, A.; Chasnov, J.; Albrecht, G. F.

    1990-01-01

    In this paper, we apply two theoretical turbulence models, DIA and the recent GISS model, to study properties of a turbulent channel flow. Both models provide a turbulent kinetic energy spectral function E(k) as the solution of a non-linear equation; the two models employ the same source function but different closures. The source function is characterized by a rate n sub s (k) which is derived from the complex eigenvalues of the Orr-Sommerfeld (OS) equation in which the basic flow is taken to be of a Poiseuille type. The O-S equation is solved for a variety of Reynolds numbers corresponding to available experimental data. A physical argument is presented whereby the central line velocity characterizing the basic flow, U0 sup L, is not to be identified with the U0 appearing in the experimental Reynolds number. The theoretical results are compared with two types of experimental data: (1) turbulence bulk properties, and (2) properties that depend strongly on the structure of the turbulence spectrum at low wave numbers. The only existing analytical expression for Pi (k) cannot be used in the present case because it applies to the case of a flat plate, not a finite channel.

  19. Broad photoelectron spectrum and lowered electron affinity due to hydrogen in ZnOH: A joint experimental and theoretical study

    Science.gov (United States)

    Iordanov, I.; Gunaratne, K. D. D.; Harmon, C. L.; Sofo, J. O.; Castleman, A. W.

    2012-06-01

    We report a combined experimental and theoretical photoelectron spectroscopy study of ZnOH-. We find that the electron binding energy spectrum of ZnOH- reveals a broad and featureless peak between 1.4 and 2.4 eV in energy. The vertical detachment energy (VDE) of ZnOH- is determined to be 1.78 eV, which is lower than the 2.08 eV VDE of ZnO-. Our theoretical calculations match the VDE of ZnOH- accurately, but we find that the broadness of the peak cannot be explained by rotational or vibrational state excitation. The broadness of this peak is in strong contrast to the narrow and easily understood first peak of the ZnO spectrum, which features a well-resolved vibrational progression that can be readily explained by calculating the Franck-Condon transition factors. This study provides spectroscopic evidence of the effect of hydrogen on diatomic ZnO.

  20. Excitons in van der Waals Heterostructures: A theoretical study

    DEFF Research Database (Denmark)

    Latini, Simone

    )electronics devices, e.g. light emitting diodes, solar cells, ultra-fast photodetectors, transistors etc., have been successfully fabricated. It is well established that for isolated 2D semiconductors and vdWHs the optical response is governed by excitonic effects. While it is understood that the reduced amount...... of electronic screening in freestanding 2D materials is the main origin of extraordinarily strongly bound excitons, a theoretical understanding of excitonic effects and of how the electronic screening is affected for the more complex case of multi-layer structures is still lacking due to the computational...... in a generalized hydrogenic model to compute exciton binding energies in isolated, supported, or encapsulated 2D semiconductors. The non-locality of the dielectric screening is inherently included in our method and we can successfully describe the non-hydrogenic Rydberg series of low-dimensional systems...

  1. The power of theoretical knowledge.

    Science.gov (United States)

    Alligood, Martha Raile

    2011-10-01

    Nursing theoretical knowledge has demonstrated powerful contributions to education, research, administration and professional practice for guiding nursing thought and action. That knowledge has shifted the primary focus of the nurse from nursing functions to the person. Theoretical views of the person raise new questions, create new approaches and instruments for nursing research, and expand nursing scholarship throughout the world.

  2. Theoretical interpretation of data from high-energy nuclear collisions

    International Nuclear Information System (INIS)

    Fai, G.

    1988-09-01

    Nuclear collision data at energies ranging from medium to relativistic are interpreted theoretically. The major objective is a better understanding of high-energy heavy-ion collisions, with particular emphasis on the properties of excited nuclear matter. Further progress towards a satisfactory description of excited subsaturation nuclear matter is achieved. The mean free path of a nucleon in nuclear matter, which is a critical parameter in assessing the applicability of certain nuclear collision models, is investigated. Experimental information is used together with theoretical concepts in collaborations with experimentalists in order to learn about the reaction mechanism and about excited nuclear matter properties. In the framework of a more strictly theoretical program development, subnuclear degrees of freedom and nonlinear phenomena in model field theories are studied

  3. Accelerator simulation and theoretical modelling of radiation effects (SMoRE)

    CERN Document Server

    2018-01-01

    This publication summarizes the findings and conclusions of the IAEA coordinated research project (CRP) on accelerator simulation and theoretical modelling of radiation effects, aimed at supporting Member States in the development of advanced radiation-resistant structural materials for implementation in innovative nuclear systems. This aim can be achieved through enhancement of both experimental neutron-emulation capabilities of ion accelerators and improvement of the predictive efficiency of theoretical models and computer codes. This dual approach is challenging but necessary, because outputs of accelerator simulation experiments need adequate theoretical interpretation, and theoretical models and codes need high dose experimental data for their verification. Both ion irradiation investigations and computer modelling have been the specific subjects of the CRP, and the results of these studies are presented in this publication which also includes state-ofthe- art reviews of four major aspects of the project...

  4. The person-oriented approach: A short theoretical and practical guide

    Directory of Open Access Journals (Sweden)

    Lars R. Bergman

    2014-05-01

    Full Text Available A short overview of the person-oriented approach is given as a guide to the researcher interested in carrying out person-oriented research. Theoretical, methodological, and practical considerations of the approach are discussed. First, some historical roots are traced, followed by a description of the holisticinteractionistic research paradigm, which provided the general framework for the development of the modern person-oriented approach. The approach has both a theoretical and a methodological facet and after presenting its key theoretical tenets, an overview is given of some common person-oriented methods. Central to the person-oriented approach is a system view with its components together forming a pattern regarded as indivisible. This pattern should be understood and studied as a whole, not broken up into pieces (variables that are studied as separate entities. Hence, usually methodological tools are used by which whole patterns are analysed (e.g. cluster analysis. An empirical example is given where the pattern development of school grades is studied.

  5. Spectroscopic and theoretical studies on the aromaticity of pyrrol-2-yl-carbonyl conformers

    Science.gov (United States)

    Dubis, Alina T.; Wojtulewski, Sławomir; Filipkowski, Karol

    2013-06-01

    The aromaticity of s-cis and s-trans pyrrol-2-yl carbonyl conformers was studied by FT-IR, 1H NMR spectroscopy and DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The Harmonic Oscillator Model of Aromaticity (HOMA) and Nucleus Independent Chemical Shift (NICS) indices were calculated to estimate π-electron delocalization in the pyrrole ring. The usefulness of infrared spectroscopy in the evaluation of the aromaticity of the homogeneous set of pyrroles is discussed. The influence of 2-substitution on different aspects of aromaticity and stability of the pyrrol-2-yl carbonyl conformers is also discussed. It is concluded that the substitution effect of the title pyrrole derivatives can be explained on the basis of theoretical and experimental measurements of π-electron delocalization, including IR data.

  6. Department of Theoretical Physics - Overview

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    2000-01-01

    Full text: Research activity of the Department of Theoretical Physics concerns theoretical high-energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and of relativistic heavy-ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research, yet the more formal problems are also considered. The detailed summary of the research projects and of the results obtained in various fields is given in the abstracts. Our Department actively collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular members of our Department participate in the EC network which allows mobility of researchers. Several members of our Department have also participated in the research projects funded by the Polish Committee for Scientific Research (KBN). The complete list of grants is listed separately. Besides pure research, members of our Department are also involved in graduate and undergraduate teaching activity both at our Institute as well as at other academic institutions in Cracow. At present five students are working for their Ph.D. or MSc degrees under supervision of the senior members from the Department. We continue our participation at the EC SOCRATES-ERASMUS educational programme which allows exchange of graduate students between our Department and the Department of Physics of the University of Durham in the UK. (author)

  7. Theoretical solid state physics

    CERN Document Server

    Haug, Albert

    2013-01-01

    Theoretical Solid State Physics, Volume 1 focuses on the study of solid state physics. The volume first takes a look at the basic concepts and structures of solid state physics, including potential energies of solids, concept and classification of solids, and crystal structure. The book then explains single-electron approximation wherein the methods for calculating energy bands; electron in the field of crystal atoms; laws of motion of the electrons in solids; and electron statistics are discussed. The text describes general forms of solutions and relationships, including collective electron i

  8. Theoretical Study on the Dynamic Behavior of Pipes Conveying Gas-Liquid Flow

    Directory of Open Access Journals (Sweden)

    Enrique Ortiz-Vidal L.

    2018-01-01

    Full Text Available The dynamic behavior of clamped-clamped straight pipes conveying gas-liquid two-phase flow is theoretically investigated, specifically the effect of the flow parameters on the frequency of the system. First, the equation of motion is derived based on the classic Païdoussis formulation. Assuming Euler-Bernoulli beam theory, small-deflection approximation and no-slip homogeneous model, a coupled fluid-structure fourth-order partial differential equation (PDE is obtained. Then, the equation of motion is rendered dimensionless and discretized through Galerkin’s method. That method transforms the PDE into a set of Ordinary Differential Equations (ODEs. The system frequency is obtained by solving the system of ODEs by allowing the determinant to be equal to zero. System frequencies for different geometries, structural properties and flow conditions have been calculated. The results show that the system frequency decreases with increasing two-phase flow velocity. By contrast, the former increases with increasing homogeneous void fraction. These theoretical results are in agreement with experimental findings reported in the literature. Furthermore, even for typical two phase flow conditions, the system can become unstable for inadequate chooses of geometry or material of the pipe.

  9. Theoretical study on the nucleophilic fluoroalkylation of propylene oxide with fluorinated sulfones

    Directory of Open Access Journals (Sweden)

    Han Ling-Li

    2013-01-01

    Full Text Available The path of nucleophilic fluoroalkylation reaction of propylene oxide with PhSO2CYF- (Y=F,H, and PhSO2, respectively in gas phase and in Et2O solvent were studied theoretically. The nucleophilic fluoroalkylation of propylene oxide with fluorinated carbanions was probed by the reactivity comparison between (benzenesulfonylmonofluoromethyl anion (PhSO2CHF-, (benzenesulfonyl difluoromethyl anion (PhSO2CF2-, and bis(benzenesul-fonyl monofluoromethyl anion ((PhSO22CF-. The nucleophilicity reactivity order of PhSO2CYF- (Y = F, H, and PhSO2 is [(PhSO22CF-] > PhSO2CHF- > PhSO2CF2-, which indicates that introducing another electron-withdrawing benzenesulfonyl group is an effective way to significantly increase the nucleophilicity of the fluorinate carbanions. For comparison, we also studied the nucleophilic addition reactions of propylene oxide with chlorine substituted carbanion PhSO2CHCl-. The calculated results show that the nucleophilicity of PhSO2CYF- is better than that of PhSO2CHCl- for the ring opening reaction with propylene oxide. The calculated results are in good agreement with the available experiments.

  10. Theoretical and experimental study of image formation in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Prunier epouse Mory, Claudie

    1985-01-01

    This thesis contains a theoretical and experimental study of image formation in a dedicated scanning transmission electron microscope (STEM). Using a detailed description of the different optical elements between the field emission source and the specimen, one calculates the shape and size of the primary probe of electrons impinging on the sample. This modelization enables to estimate the spatial resolution in the different imaging or microanalytical modes. The influence of the specimen and the role of the various detectors are taken into account to calculate the point spread function of the instrument in STEM imaging modes. An experimental study of the characteristic properties of phase contrast bright field micrographs and incoherent dark field ones is performed by comparison of digitally recorded images in similar conditions. Spatial resolution, contrast and signal/noise ratio are assessed by correlation methods, Fourier analysis and statistical considerations; one can deduce the optimum focusing conditions. Limits such as the point resolution on quasi-atomic metallic clusters are determined and an analysis of the capabilities of signal mixing concludes this work. Applications are offered in various domains such as the visualisation of small metallic particles, biomolecules and unstained biological sections. (author) [fr

  11. Toward an Integrative Theoretical Framework for Explaining Beliefs about Wife Beating: A Study among Students of Nursing from Turkey

    Science.gov (United States)

    Haj-Yahia, Muhammad M.; Uysal, Aynur

    2011-01-01

    An integrative theoretical framework was tested as the basis for explaining beliefs about wife beating among Turkish nursing students. Based on a survey design, 406 nursing students (404 females) in all 4 years of undergraduate studies completed a self-administered questionnaire. Questionnaires were distributed and collected from the participants…

  12. Theoretical Model of Professional Competence Development in Dual-Specialty Students (On the Example of the "History, Religious Studies" Specialty)

    Science.gov (United States)

    Karimova, A. E.; Amanova, A. S.; Sadykova, A. M.; Kuzembaev, N. E.; Makisheva, A. T.; Kurmangazina, G. Zh.; Sakenov, Janat

    2016-01-01

    The article explores the significant problem of developing a theoretical model of professional competence development in dual-specialty students (on the example of the "History, Religious studies" specialty). In order to validate the specifics of the professional competence development in dual-specialty students (on the example of the…

  13. Theoretical Mathematics

    Science.gov (United States)

    Stöltzner, Michael

    Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.

  14. Theoretical/best practice energy use in metalcasting operations

    Energy Technology Data Exchange (ETDEWEB)

    Schifo, J. F. [KERAMIDA Environmental, Inc., Indianapolis, IN (United States); Radia, J. T. [KERAMIDA Environmental, Inc., Indianapolis, IN (United States)

    2004-05-01

    This study determined the theoretical minimum energy requirements for melting processes for all ferrous and noferrous engenieering alloys. Also the report details the Best Practice energy consumption for the industry.

  15. The theoretical preconditions for problem situation realization while studying information technology at school

    Directory of Open Access Journals (Sweden)

    Ольга Александровна Прусакова

    2012-03-01

    Full Text Available Within the framework of modern pedagogy and educational practice there have been worked out and realized various theoretical conceptions, theories, educational approaches including humanistic, personality-oriented, activity-oriented, competence-oriented. One of such approaches to education and personality development is the problem-solving approach.

  16. An experimental and theoretical kinetic study of the reaction of OH radicals with tetrahydrofuran

    KAUST Repository

    Giri, Binod

    2016-06-24

    Tetrahydrofuran (CHO, THF) and its alkylated derivatives of the cyclic ether family are considered to be promising future biofuels. They appear as important intermediates during the low-temperature oxidation of conventional hydrocarbon fuels and of heavy biofuels such as long-chain fatty acid methyl esters. The reaction of tetrahydrofuran with OH radicals was investigated in a shock tube, over a temperature range of 800-1340 K and at pressures near 1.5 bar. Hydroxyl radicals were generated by the rapid thermal decomposition of tert-butyl hydroperoxide, and a UV laser absorption technique was used to monitor the mole fraction of OH radicals. High-level CCSD(T)/cc-pV(D,T)Z//MP2/aug-cc-pVDZ quantum chemical calculations were performed to explore the chemistry of the THF+OH reaction system. Our calculations reveal that the THF+OH (R1) reaction proceeds via either direct or indirect H-abstraction from various sites, leading to the formation of tetrahydrofuran-2-yl (THF-R2) or tetrahydrofuran-3-yl (THF-R3) radicals and water. Theoretical kinetic analysis revealed that both channels are important under conditions relevant to combustion. To our knowledge, this is the first direct experimental and theoretical kinetic study of the reaction of tetrahydrofuran with OH radicals at high temperatures. The following theoretical rate expressions (in units of cmmols) are recommended for combustion modeling in the temperature range 800-1350 K: . k1(T)=4.11×1040.16em0ex(TK)2.69exp(1316.80.16em0exKT)2.em0ex0.16em0ex(THF+OH→Products) . k2(T)=6.930.16em0ex×10110.16em0ex(TK)0.41exp(-106.80.16em0exKT)2.em0ex0.16em0ex(THF+OH→THF-R20.16em0ex+H2O) . k3(T)=4.120.16em0ex×1030.16em0ex(TK)3.02exp(456.90.16em0exKT)2.em0ex0.16em0ex(THF+OH→THF-R30.16em0ex+H2O) . .

  17. Theoretical Framework of Leadership in Higher Education of England and Wales

    Science.gov (United States)

    Mukan, Nataliya; Havrylyuk, Marianna; Stolyarchuk, Lesia

    2015-01-01

    In the article the theoretical framework of leadership in higher education of England and Wales has been studied. The main objectives of the article are defined as analysis of scientific and pedagogical literature, which highlights different aspects of the problem under research; characteristic of the theoretical fundamentals of educational…

  18. A theoretical and experimental study of the thermal degradation of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Groenli, Morten G.

    1996-12-31

    This thesis relates to the thermal degradation of biomass covering a theoretical and experimental study in two parts. In the first part, there is presented an experimental and modeling work on the pyrolysis of biomass under regimes controlled by chemical kinetics, and the second part presents an experimental and modeling work on the pyrolysis of biomass under regimes controlled by heat and mass transfer. Five different celluloses, and hemicellulose and lignin isolated from birch and spruce have been studied by thermogravimetry. The thermo grams of wood species revealed different weight loss characteristics which can be attributed to their different chemical composition. The kinetic analysis gave activation energies between 210 and 280 kJ/mole for all the celluloses, and a model of independent parallel reactions was successfully used to describe the thermal degradation. In the second part of the thesis there is presented experimental and modeling work on the pyrolysis of biomass under regimes controlled by heat and mass transfer. The effect of heating conditions on the product yields distribution and reacted fraction was investigated. The experiments show that heat flux alters the pyrolysis products as well as the intra particle temperatures to the greatest extent. A comprehensive mathematical model which can simulate drying and pyrolysis of moist wood is presented. The simulation of thermal degradation and heat transport processes agreed well with experimental results. 198 refs., 139 figs., 68 abs.

  19. Kinetic Adsorption Study of Silver Nanoparticles on Natural Zeolite: Experimental and Theoretical Models

    Directory of Open Access Journals (Sweden)

    Alvaro Ruíz-Baltazar

    2015-12-01

    Full Text Available In this research, the adsorption capacity of Ag nanoparticles on natural zeolite from Oaxaca is presented. In order to describe the adsorption mechanism of silver nanoparticles on zeolite, experimental adsorption models for Ag ions and Ag nanoparticles were carried out. These experimental data obtained by the atomic absorption spectrophotometry technique were compared with theoretical models such as Lagergren first-order, pseudo-second-order, Elovich, and intraparticle diffusion. Correlation factors R2 of the order of 0.99 were observed. Analysis by transmission electron microscopy describes the distribution of the silver nanoparticles on the zeolite outer surface. Additionally, a chemical characterization of the material was carried out through a dilution process with lithium metaborate. An average value of 9.3 in the Si/Al ratio was observed. Factors such as the adsorption behavior of the silver ions and the Si/Al ratio of the zeolite are very important to support the theoretical models and establish the adsorption mechanism of Ag nanoparticles on natural zeolite.

  20. Theoretical study of optical conductivity of graphene with magnetic and nonmagnetic adatoms

    Science.gov (United States)

    Majidi, Muhammad Aziz; Siregar, Syahril; Rusydi, Andrivo

    2014-11-01

    We present a theoretical study of the optical conductivity of graphene with magnetic and nonmagnetic adatoms. First, by introducing an alternating potential in a pure graphene, we demonstrate a gap formation in the density of states and the corresponding optical conductivity. We highlight the distinction between such a gap formation and the so-called Pauli blocking effect. Next, we apply this idea to graphene with adatoms by introducing magnetic interactions between the carrier spins and the spins of the adatoms. Exploring various possible ground-state spin configurations of the adatoms, we find that the antiferromagnetic configuration yields the lowest total electronic energy and is the only configuration that forms a gap. Furthermore, we analyze four different circumstances leading to similar gaplike structures and propose a means to interpret the magneticity and the possible orderings of the adatoms on graphene solely from the optical conductivity data. We apply this analysis to the recently reported experimental data of oxygenated graphene.

  1. A theoretical model of multielectrode DBR lasers

    DEFF Research Database (Denmark)

    Pan, Xing; Olesen, Henning; Tromborg, Bjarne

    1988-01-01

    A theoretical model for two- and three-section tunable distributed Bragg reflector (DBR) lasers is presented. The static tuning properties are studied in terms of threshold current, linewidth, oscillation frequency, and output power. Regions of continuous tuning for three-section DBR lasers...

  2. Theoretical physics division

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Research activities of the theoretical physics division for 1979 are described. Short summaries are given of specific research work in the following fields: nuclear structure, nuclear reactions, intermediate energy physics, elementary particles [fr

  3. Theoretical and experimental study of AC electrical conduction mechanism in the low temperature range of p-CuIn3Se5

    Science.gov (United States)

    Essaleh, L.; Amhil, S.; Wasim, S. M.; Marín, G.; Choukri, E.; Hajji, L.

    2018-05-01

    In the present work, an attempt has been made to study theoretically and experimentally the AC electrical conduction mechanism in disordered semiconducting materials. The key parameter considered in this analysis is the frequency exponent s(ω , T) =( ∂ln(σAC(ω , T))/∂ ln(ω)T , where σAC is the AC electrical conductivity that depends on angular frequency ω and temperature T. In the theoretical part of this work, the effect of the barrier hopping energy, the polaron radius and the characteristic relaxation time is considered. The theoretical models of Quantum Mechanical Tunneling (QMT), Non overlapping Small Polaron Tunneling (NSPT), Overlapping Large Polaron Tunneling (OLPT) and Correlated Barrier Hopping (CBH) are considered to fit experimental data of σAC in p-CuIn3Se5 (p-CIS135) in the low temperature range up to 96 K. Some important parameters, as the polaron radius, the localization length and the barrier hopping energies, are estimated and their temperature and frequency dependence discussed.

  4. Towards Culturally Relevant Classroom Science: A Theoretical Framework Focusing on Traditional Plant Healing

    Science.gov (United States)

    Mpofu, Vongai; Otulaja, Femi S.; Mushayikwa, Emmanuel

    2014-01-01

    A theoretical framework is an important component of a research study. It grounds the study and guides the methodological design. It also forms a reference point for the interpretation of the research findings. This paper conceptually examines the process of constructing a multi-focal theoretical lens for guiding studies that aim to accommodate…

  5. Theoretical Studies of Aqueous Systems above 25 deg C. 2. The Iron - Water System

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Derek

    1971-09-15

    A theoretical study of the iron-water system at elevated temperatures is reported. Values for the equilibrium constants for the principle reactions in the system up to 374 deg C, obtained by a method described previously, are given and equilibrium diagrams are presented that illustrate the results for 50, 150, 250 and 350 deg C. The results indicate that, among other things, the most important metal-bearing ions in the iron-water system at elevated temperatures are Fe(OH){sub 2}+, Fe(OH)+ and HFeO{sub 2}- The conditions for the stability of solid iron oxides are also examined. Finally, some limitations of the thermodynamic approach to corrosion problems are discussed briefly

  6. Theoretical study of molecular vibration and Application to linear triatomic molecules: case of OCS

    International Nuclear Information System (INIS)

    Andrianavalomahefa, A.

    2014-01-01

    Our aim is to give a theoretical approach to the calculation of vibrational energy levels of polyatomic molecules. By using matrix calculation, we have to solve an eigenvalue equation that gives normal vibration frequencies of the system. A basis change introduces normal coordinates of vibration, which diagonalize the Hamiltonian. The harmonic approximation gives a rough evaluation of parameters which describe the system. Then, we introduce nonlinear terms to take into account the anharmonicity of interatomic bounds. Morse oscillator gives good approximation for diatomic molecules. We consider cubic and quartic potential terms for polyatomic molecules. We treat the problem both in classical and quantum approach. The results thus obtained are applied to study longitudinal vibration of carbonyl sulfide. [fr

  7. SOCIOLOGICAL UNDERSTANDING OF INTERNET: THEORETICAL APPROACHES TO THE NETWORK ANALYSIS

    Directory of Open Access Journals (Sweden)

    D. E. Dobrinskaya

    2016-01-01

    Full Text Available The network is an efficient way of social structure analysis for contemporary sociologists. It gives broad opportunities for detailed and fruitful research of different patterns of ties and social relations by quantitative analytical methods and visualization of network models. The network metaphor is used as the most representative tool for description of a new type of society. This new type is characterized by flexibility, decentralization and individualization. Network organizational form became the dominant form in modern societies. The network is also used as a mode of inquiry. Actually three theoretical network approaches in the Internet research case are the most relevant: social network analysis, “network society” theory and actor-network theory. Every theoretical approach has got its own notion of network. Their special methodological and theoretical features contribute to the Internet studies in different ways. The article represents a brief overview of these network approaches. This overview demonstrates the absence of a unified semantic space of the notion of “network” category. This fact, in turn, points out the need for detailed analysis of these approaches to reveal their theoretical and empirical possibilities in application to the Internet studies

  8. Inhibition of mild steel corrosion in acid solution by Pheniramine drug: Experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Ahamad, Ishtiaque [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India); Prasad, Rajendra [Department of Chemistry, SGB Amravati University, Amravati 444 602 (India); Quraishi, M.A., E-mail: maquraishi@rediffmail.co [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India)

    2010-09-15

    Inhibition of mild steel corrosion in 1 M HCl solution by Pheniramine drug was studied using weight loss, electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization measurements. The values of activation energy (E{sub a}) and different thermodynamic parameters such as adsorption equilibrium constant (K{sub ads}), free energy of adsorption ({Delta}G{sub ads}{sup o}), adsorption enthalpy ({Delta}H{sub ads}{sup o}) and adsorption entropy ({Delta}S{sub ads}{sup o}) were calculated and discussed. The adsorption process of studied drug on mild steel surface obeys the Langmuir adsorption isotherm. Potentiodynamic polarization measurements showed that Pheniramine is mixed-type inhibitor. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  9. Theoretical study on the thermal and optical features of a diode side-pumped alkali laser

    Science.gov (United States)

    Han, Juhong; Liu, Xiaoxu; Wang, Hongyuan; Cai, He; An, Guofei; Zhang, Wei; Wang, You

    2018-03-01

    As one of the most hopeful candidates to achieve high power performances, a diode-pumped alkali laser (DPAL) has attracted a lot of attention in the last decade. Comparing with a diode end-pumped alkali laser (DEPAL), a diode side-pumped alkali laser (DSPAL) has great potentiality to realize an even-higher output of alkali lasers. However, there are few related researching studies concern DSPAL. In this paper, we introduce a theoretical model to investigate the physical features of a double-directions side-pumped alkali laser. The distributions of the population density, temperature, and absorption power at the cross section of a vapor cell are systematically studied. The analyses should be valuable for design of a steady high-powered DPAL.

  10. Robust recognition via information theoretic learning

    CERN Document Server

    He, Ran; Yuan, Xiaotong; Wang, Liang

    2014-01-01

    This Springer Brief represents a comprehensive review of information theoretic methods for robust recognition. A variety of information theoretic methods have been proffered in the past decade, in a large variety of computer vision applications; this work brings them together, attempts to impart the theory, optimization and usage of information entropy.The?authors?resort to a new information theoretic concept, correntropy, as a robust measure and apply it to solve robust face recognition and object recognition problems. For computational efficiency,?the brief?introduces the additive and multip

  11. Experimental and theoretical study of particle transport in the TCV Tokamak

    International Nuclear Information System (INIS)

    Fable, E.

    2009-06-01

    The main scope of this thesis work is to compare theoretical models with experimental observations on particle transport in particular regimes of plasma operation from the Tokamak à Configuration Variable (TCV) located at CRPP–EPFL in Lausanne. We introduce the main topics in Tokamak fusion research and the challenging problems in the first Chapter. A particular attention is devoted to the modelling of heat and particle transport. In the second Chapter the experimental part is presented, including an overview of TCV capabilities, a brief review of the relevant diagnostic systems, and a discussion of the numerical tools used to analyze the experimental data. In addition, the numerical codes that are used to interpret the experimental data and to compare them with theoretical predictions are introduced. The third Chapter deals with the problem of understanding the mechanisms that regulate the transport of energy in TCV plasmas, in particular in the electron Internal Transport Barrier (eITB) scenario. A radial transport code, integrated with an external module for the calculation of the turbulence-induced transport coefficients, is employed to reproduce the experimental scenario and to understand the physics at play. It is shown how the sustainment of an improved confinement regime is linked to the presence of a reversed safety factor profile. The improvement of confinement in the eITB regime is visible in the energy channel and in the particle channel as well. The density profile shows strong correlation with the temperature profile and has a large local logarithmic gradient. This is an important result obtained from the TCV eITB scenario analysis and is presented in the fourth Chapter. In the same chapter we present the estimate of the particle diffusion and convection coefficients obtained from density transient experiments performed in the eITB scenario. The theoretical understanding of the strong correlation between density and temperature observed in the e

  12. Theoretical and experimental high energy physics

    International Nuclear Information System (INIS)

    Gasiorowicz, S.; Ruddick, K.

    1988-01-01

    This report discusses experimental and theoretical work in High Energy Physics. Some topics discussed are: quantum field theory; supersymmetry; cosmology; superstring model; relic photinos; inflationary universe; dark matter; standard model; supernovae; semileptonic decay; quantum Langevin equation; underground neutrino detection at Soudan; strange quark systems; cosmic ray detection; superconducting super collider detectors; and studies of direct photon production

  13. Experimental and theoretical studies on the structural, spectroscopic and hydrogen bonding on 4-nitro-n-(2,4-dinitrophenyl) benzenamine

    Science.gov (United States)

    Subhapriya, G.; Kalyanaraman, S.; Jeyachandran, M.; Ragavendran, V.; Krishnakumar, V.

    2018-04-01

    Synthesized 4-nitro-N-(2,4-dinitrophenyl) benzenamine (NDPBA) molecule was confirmed applying the tool of NMR. Theoretical prediction addressed the NMR chemical shifts and correlated well with the experimental data. The molecule subjected to theoretical DFT at 6-311++G** level unraveled the spectroscopic and structural properties of the NDPBA molecule. Moreover the structural features proved the occurrence of intramolecular Nsbnd H· · O hydrogen bonding in the molecule which was further confirmed with the help of Frontier molecular orbital analysis. Vibrational spectroscopic characterization through FT-IR and Raman experimentally and theoretically gave an account for the vibrational properties. An illustration of the topology of the molecule theoretically helped also in finding the hydrogen bonding energy.

  14. Theoretical study of the self-assembly of Janus Bottlebrush Polymers from A-Branch-B Diblock Macromonomers

    Science.gov (United States)

    Gadelrab, Karim; Alexander-Katz, Alfredo; LaboratoryTheoretical Soft Materials Team

    The self-assembly of block copolymers BCP has provided an impressive control over the nanoscale structure of soft matter. While the main focus of the research in the field has been directed towards simple linear diblocks, the development of advanced polymer architecture provided improved performance and access to new structures. In particular, bottlebrush BCPs (BBCPs) have interesting characteristics due to their dense functionality, high molecular weight, low levels of entanglement, and tendency to efficiently undergo rapid bulk phase separation. In this work, we are interested in theoretically studying the self-assembly of Janus-type ``A-branch-B'' BBCPs where A and B blocks can phase separate with the bottlebrush polymer backbone serving as the interface between the two blocks. Hence, the polymer backbone adds an extra constraint on the equilibrium spacing between neighboring linear diblock chains. In this regard, the segment length of the backbone separating the AB junctions has a direct effect of the observed domain spacing and effective segregation strength of the AB blocks. We employ self-consistent field theoretic SCFT simulations to capture the effect of volume fraction of different constituents and construct a phase diagram of the accessible morphologies of these BBCPs.

  15. Theoretical & Experimental Studies of Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    McFarland, Kevin [Univ. of Rochester, NY (United States)

    2012-10-04

    Abstract High energy physics has been one of the signature research programs at the University of Rochester for over 60 years. The group has made leading contributions to experimental discoveries at accelerators and in cosmic rays and has played major roles in developing the theoretical framework that gives us our ``standard model'' of fundamental interactions today. This award from the Department of Energy funded a major portion of that research for more than 20 years. During this time, highlights of the supported work included the discovery of the top quark at the Fermilab Tevatron, the completion of a broad program of physics measurements that verified the electroweak unified theory, the measurement of three generations of neutrino flavor oscillations, and the first observation of a ``Higgs like'' boson at the Large Hadron Collider. The work has resulted in more than 2000 publications over the period of the grant. The principal investigators supported on this grant have been recognized as leaders in the field of elementary particle physics by their peers through numerous awards and leadership positions. Most notable among them is the APS W.K.H. Panofsky Prize awarded to Arie Bodek in 2004, the J.J. Sakurai Prizes awarded to Susumu Okubo and C. Richard Hagen in 2005 and 2010, respectively, the Wigner medal awarded to Susumu Okubo in 2006, and five principal investigators (Das, Demina, McFarland, Orr, Tipton) who received Department of Energy Outstanding Junior Investigator awards during the period of this grant. The University of Rochester Department of Physics and Astronomy, which houses the research group, provides primary salary support for the faculty and has waived most tuition costs for graduate students during the period of this grant. The group also benefits significantly from technical support and infrastructure available at the University which supports the work. The research work of the group has provided educational opportunities

  16. Theoretical Studies of Hydrogen Storage Alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Hannes

    2012-03-22

    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  17. Theoretical study of relative width of photonic band gap for the 3-D ...

    Indian Academy of Sciences (India)

    ... of refractive index and relative radius of the photonic band gap for the fcc closed packed 3-D dielectric microstructure are reported and comparison of experimental observations and theoretical predictions are given. This work is useful for the understanding of photonic crystals and occurrence of the photonic band gap.

  18. Optical gain coefficients of silicon: a theoretical study

    Science.gov (United States)

    Tsai, Chin-Yi

    2018-05-01

    A theoretical model is presented and an explicit formula is derived for calculating the optical gain coefficients of indirect band-gap semiconductors. This model is based on the second-order time-dependent perturbation theory of quantum mechanics by incorporating all the eight processes of photon/phonon emission and absorption between the band edges of the conduction and valence bands. Numerical calculation results are given for Si. The calculated absorption coefficients agree well with the existing fitting formula of experiment data with two modes of phonons: optical phonons with energy of 57.73 meV and acoustic phonons with energy of 18.27 meV near (but not exactly at) the zone edge of the X-point in the dispersion relation of phonons. These closely match with existing data of 57.5 meV transverse optical (TO) phonons at the X4-point and 18.6 meV transverse acoustic (TA) phonons at the X3-point of the zone edge. The calculated results show that the material optical gain of Si will overcome free-carrier absorption if the energy separation of quasi-Fermi levels between electrons and holes exceeds 1.15 eV.

  19. Theoretical and Conceptual Frameworks Used in Research on Family-School Partnerships

    Science.gov (United States)

    Yamauchi, Lois A.; Ponte, Eva; Ratliffe, Katherine T.; Traynor, Kevin

    2017-01-01

    This study investigated the theoretical frameworks used to frame research on family-school partnerships over a five-year period. Although many researchers have described their theoretical approaches, little has been written about the diversity of frameworks used and how they are applied. Coders analyzed 215 journal articles published from 2007 to…

  20. Theoretical developments in SUSY

    Energy Technology Data Exchange (ETDEWEB)

    Shifman, M. [University of Minnesota, William I. Fine Theoretical Physics Institute, Minneapolis, MN (United States)

    2009-01-15

    I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I review theoretical developments of the recent years in non-perturbative supersymmetry. (orig.)

  1. Theoretical Developments in SUSY

    Science.gov (United States)

    Shifman, M.

    2009-01-01

    I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I will review theoretical developments of the recent years in non-perturbative supersymmetry.

  2. Theoretical developments in SUSY

    International Nuclear Information System (INIS)

    Shifman, M.

    2009-01-01

    I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I review theoretical developments of the recent years in non-perturbative supersymmetry. (orig.)

  3. Complexation of the strontium cation with a macrocyclic lactam receptor: Experimental and theoretical study

    Czech Academy of Sciences Publication Activity Database

    Makrlík, E.; Záliš, Stanislav; Vaňura, P.

    2016-01-01

    Roč. 214, FEB 2016 (2016), s. 171-174 ISSN 0167-7322 Institutional support: RVO:61388955 Keywords : strontium cation * macrocyclic lactam receptor Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.648, year: 2016

  4. Department of Theoretical Physics. Annual Report 1989

    International Nuclear Information System (INIS)

    1990-01-01

    Abstracts of studies done in 1989 at the Department of Theoretical Physics of the H. Niewodniczanski Institute of Nuclear Physics in Cracow are given together with the lists of personnel, guests, conference papers, lectures, habilitations, ph.d. theses and publications. 45 refs. (A.S.)

  5. A theoretical and spectroscopic study of conformational structures of piroxicam

    Science.gov (United States)

    Souza, Kely Ferreira de; Martins, José A.; Pessine, Francisco B. T.; Custodio, Rogério

    2010-02-01

    Piroxicam (PRX) has been widely studied in an attempt to elucidate the causes and mechanisms of its side effects, mainly the photo-toxicity. In this paper fluorescence spectra in non-protic solvents and different polarities were carried out along with theoretical calculations. Preliminary potential surfaces of the keto and enol forms were obtained at AM1 level of theory providing the most stable conformers, which had their structure re-optimized through the B3LYP/CEP-31G(d,p) method. From the optimized structures, the electronic spectra were calculated using the TD-DFT method in vacuum and including the solvent effect through the PCM method and a single water molecule near PRX. A new potential surface was constructed to the enol tautomer at DFT level and the most stable conformers were submitted to the QST2 calculations. The experimental data showed that in apolar media, the solution fluorescence is raised. Based on conformational analysis for the two tautomers, keto and enol, the results indicated that the PRX-enol is the main tautomer related to the drug fluorescence, which is reinforced by the spectra results, as well as the interconvertion barrier obtained from the QST2 calculations. The results suggest that the PRX one of the enol conformers presents great possibility of involvement in the photo-toxicity mechanisms.

  6. A Theoretical Approach

    African Journals Online (AJOL)

    NICO

    L-rhamnose and L-fucose: A Theoretical Approach ... L-ramnose and L-fucose, by means of the Monte Carlo conformational search method. The energy of the conformers ..... which indicates an increased probability for the occurrence of.

  7. Theoretical and Experimental Analysis of Adsorption in Surface-based Biosensors

    DEFF Research Database (Denmark)

    Hansen, Rasmus

    The present Ph.D. dissertation concerns the application of surface plasmon resonance (SPR) spectroscopy, which is a surface-based biosensor technology, for studies of adsorption dynamics. The thesis contains both experimental and theoretical work. In the theoretical part we develop the theory...... cell of the surface-based biosensor, in addition to the sensor surface, is investigated. In the experimental part of the thesis we use a Biacore SPR sensor to study lipase adsorption on model substrate surfaces, as well as competitive adsorption of lipase and surfactants. A part of the experimental...

  8. High-pressure structural behavior of the double perovskite Sr2CrReO6: an experimental and theoretical study

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Vaitheeswaran, G.

    2009-01-01

    The high-pressure structural behavior of Sr2CrReO6 has been studied experimentally using synchrotron radiation and the diamond anvil cell and theoretically using density functional theory. The experimental zero-pressure bulk modulus is B0=1704GPa and the pressure derivative is B0'=4.71.0. These r...

  9. Theoretical study of solar combisystems based on bikini tanks and tank-in-tank stores

    DEFF Research Database (Denmark)

    Yazdanshenas, Eshagh; Furbo, Simon

    2012-01-01

    . Originality/value - Many different Solar Combisystem designs have been commercialized over the years. In the IEA-SHC Task 26, twenty one solar combisystems have been described and analyzed. Maybe the mantle tank approach also for solar combisystems can be used with advantage? This might be possible...... if the solar heating system is based on a so called bikini tank. Therefore the new developed solar combisystems based on bikini tanks is compared to the tank-in-tank solar combisystems to elucidate which one is suitable for three different houses with low energy heating demand, medium and high heating demand.......Purpose - Low flow bikini solar combisystems and high flow tank-in-tank solar combisystems have been studied theoretically. The aim of the paper is to study which of these two solar combisystem designs is suitable for different houses. The thermal performance of solar combisystems based on the two...

  10. Current and future prospects for the application of systematic theoretical methods to the study of problems in physical oceanography

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, A., E-mail: adrian.constantin@kcl.ac.uk [Department of Mathematics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, 1090 Vienna (Austria); Johnson, R.S., E-mail: r.s.johnson@ncl.ac.uk [School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2016-09-07

    Highlights: • Systematic theoretical methods in studies of equatorial ocean dynamics. • Linear wave-current interactions in stratified flows. • Exact solutions – Kelvin waves, azimuthal non-uniform currents. • Three-dimensional nonlinear currents. • Hamiltonian formulation for the governing equations and for structure-preserving/enhancing approximations. - Abstract: This essay is a commentary on the pivotal role of systematic theoretical methods in physical oceanography. At some level, there will always be a conflict between theory and experiment/data collection: Which is pre-eminent? Which should come first? This issue appears to be particularly marked in physical oceanography, to the extreme detriment of the development of the subject. It is our contention that the classical theory of fluids, coupled with methods from the theory of differential equations, can play a significant role in carrying the subject, and our understanding, forward. We outline the philosophy behind a systematic theoretical approach, highlighting some aspects of equatorial ocean dynamics where these methods have already been successful, paving the way for much more in the future and leading, we expect, to the better understanding of this and many other types of ocean flow. We believe that the ideas described here promise to reveal a rich and beautiful dynamical structure.

  11. Photophysical properties of chirality: Experimental and theoretical studies of (R)- and (S)-binaphthol derivatives as a prototype case

    International Nuclear Information System (INIS)

    Tsuboi, Taiju; An, Zhong-fu; Nakai, Yosuke; Yin, Jun; Chen, Run-feng; Shi, Hui-fang; Huang, Wei

    2013-01-01

    Highlights: ► The effect of chirality on photophysical properties was investigated. ► The same photophysics of enantiomers was observed in solutions. ► But different photoluminescent efficiency and lifetime were found in neat film. ► The different symmetry and formation probability of dimmers may be the main reason. ► The joint experimental and theoretical study explains these differences well. - Abstract: The key monomers of binaphthol-based chiral materials, (R)- and (S)- 6,6′-dibromo-2,2′-bis(octyloxy)- 1,1′-binaphthyl (R–M and S–M, respectively), were synthesized and characterized by UV–vis absorption spectra, circular dichroism (CD) spectra, photoluminescence (PL) lifetime, PL quantum efficiency at room temperature, together with PL spectra at various temperatures between 12 K and 296 K in both film and solution. The photophysical properties of R–M and S–M were investigated in detail with a joint experimental and theoretical study, in order to reveal the effects of chirality on the π-conjugated chiral systems. Higher photoluminescent quantum efficiency and better PL spectra purity in solid film of R–M were observed and discussed

  12. Mechanistic Studies on Chabazite-Type Methanol-to-Olefin Catalysts: Insights from Time-Resolved UV/Vis Microspectroscopy Combined with Theoretical Simulations

    NARCIS (Netherlands)

    Van Speybroeck, V.; Hemelsoet, K.L.J.; De Wispelaere, K.; Qian, Q.|info:eu-repo/dai/nl/34138609X; Van der Mynsbrugge, J.; De Sterck, B.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397; Waroquier, M.

    2013-01-01

    The formation and nature of active sites for methanol conversion over solid acid catalyst materials are studied by using a unique combined spectroscopic and theoretical approach. A working catalyst for the methanol-to-olefin conversion has a hybrid organic–inorganic nature in which a cocatalytic

  13. Information-theoretic metamodel of organizational evolution

    Science.gov (United States)

    Sepulveda, Alfredo

    2011-12-01

    Social organizations are abstractly modeled by holarchies---self-similar connected networks---and intelligent complex adaptive multiagent systems---large networks of autonomous reasoning agents interacting via scaled processes. However, little is known of how information shapes evolution in such organizations, a gap that can lead to misleading analytics. The research problem addressed in this study was the ineffective manner in which classical model-predict-control methods used in business analytics attempt to define organization evolution. The purpose of the study was to construct an effective metamodel for organization evolution based on a proposed complex adaptive structure---the info-holarchy. Theoretical foundations of this study were holarchies, complex adaptive systems, evolutionary theory, and quantum mechanics, among other recently developed physical and information theories. Research questions addressed how information evolution patterns gleamed from the study's inductive metamodel more aptly explained volatility in organization. In this study, a hybrid grounded theory based on abstract inductive extensions of information theories was utilized as the research methodology. An overarching heuristic metamodel was framed from the theoretical analysis of the properties of these extension theories and applied to business, neural, and computational entities. This metamodel resulted in the synthesis of a metaphor for, and generalization of organization evolution, serving as the recommended and appropriate analytical tool to view business dynamics for future applications. This study may manifest positive social change through a fundamental understanding of complexity in business from general information theories, resulting in more effective management.

  14. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study

    Directory of Open Access Journals (Sweden)

    Phillips CJ

    2015-03-01

    Framework (TDF is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. Purpose: This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Methods: Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Results: Three main themes and associated subthemes were identified including: 1 reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings; 2 challenges using the TDF (time and resources, operationalization of the TDF and; 3 future use of the TDF. Conclusion: The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF. Keywords: barriers and enablers, behavioral change, evidence-based practice, implementation, health care, Theoretical Domains Framework

  15. Theoretical behaviorism meets embodied cognition : Two theoretical analyses of behavior

    NARCIS (Netherlands)

    Keijzer, F.A.

    2005-01-01

    This paper aims to do three things: First, to provide a review of John Staddon's book Adaptive dynamics: The theoretical analysis of behavior. Second, to compare Staddon's behaviorist view with current ideas on embodied cognition. Third, to use this comparison to explicate some outlines for a

  16. Theoretical Studies of Alfven Waves and Energetic Particle Physics in Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liu [Univ. of California, Irvine, CA (United States)

    2017-12-20

    This report summarizes major theoretical findings in the linear as well as nonlinear physics of Alfvén waves and energetic particles in magnetically confined fusion plasmas. On the linear physics, a variational formulation, based on the separation of singular and regular spatial scales, for drift-Alfvén instabilities excited by energetic particles is established. This variational formulation is then applied to derive the general fishbone-like dispersion relations corresponding to the various Alfvén eigenmodes and energetic-particle modes. It is further employed to explore in depth the low-frequency Alfvén eigenmodes and demonstrate the non-perturbative nature of the energetic particles. On the nonlinear physics, new novel findings are obtained on both the nonlinear wave-wave interactions and nonlinear wave-energetic particle interactions. It is demonstrated that both the energetic particles and the fine radial mode structures could qualitatively affect the nonlinear evolution of Alfvén eigenmodes. Meanwhile, a theoretical approach based on the Dyson equation is developed to treat self-consistently the nonlinear interactions between Alfvén waves and energetic particles, and is then applied to explain simulation results of energetic-particle modes. Relevant list of journal publications on the above findings is also included.

  17. Final Report Theoretical Studies of Surface Reactions on Metals and Electronic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jerry L. Whitten

    2012-04-23

    This proposal describes the proposed renewal of a theoretical research program on the structure and reactivity of molecules adsorbed on transition metal surfaces. A new direction of the work extends investigations to interfaces between solid surfaces, adsorbates and aqueous solutions and includes fundamental work on photoinduced electron transport into chemisorbed species and into solution. The goal is to discover practical ways to reduce water to hydrogen and oxygen using radiation comparable to that available in the solar spectrum. The work relates to two broad subject areas: photocatalytic processes and production of hydrogen from water. The objective is to obtain high quality solutions of the electronic structure of adsorbate-metal-surface-solution systems so as to allow activation barriers to be calculated and reaction mechanisms to be determined. An ab initio embedding formalism provides a route to the required accuracy. New theoretical methods developed during the previous grant period will be implemented in order to solve the large systems involved in this work. Included is the formulation of a correlation operator that is used to treat localized electron distributions such as ionic or regionally localized distributions. The correlation operator which is expressed as a two-particle projector is used in conjunction with configuration interaction.

  18. Social History as Socio-Analysis. Building a Theoretical Viewpoint to Study the Relationship Between the Public Sphere, Women and the Popular Sectors

    Directory of Open Access Journals (Sweden)

    Diana Gómez Navas

    2015-04-01

    Full Text Available DOI: http://dx.doi.org/10.17227/01234870.41folios169.185 This article shows the construction of a theoretical viewpoint in the development of research that focuses on the relationship between three categories: the public sphere, women and popular sectors. To do this, it first presents an overview of the trends found in studies focused on similar relationships. Thereafter, a theoretical view is proposed based on the main routes and epistemological and methodological assumptions of social history enlightened by the tenets of socio-analytic proposal from French sociologist Pierre Bourdieu. Thus, the main epistemological implications of Bourdieu’s perspective in light of a theoretical reflection interested in the way in which a public urban world is set in the time is presented. The urban public world is questioned particularly based on the positions held by women in the working class.

  19. Theoretical studies in medium-energy nuclear and hadronic physics

    International Nuclear Information System (INIS)

    Horowitz, C.J.; Macfarlane, M.H.; Matsui, T.; Serot, B.D.

    1993-01-01

    A proposal for theoretical nuclear physics research is made for the period April 1, 1993 through March 31, 1996. Research is proposed in the following areas: relativistic many-body theory of nuclei and nuclear matter, quasifree electroweak scattering and strange quarks in nuclei, dynamical effects in (e,e'p) scattering at large momentum transfer, investigating the nucleon's parton sea with polarized leptoproduction, physics of ultrarelativistic nucleus endash nucleus collisions, QCD sum rules and hadronic properties, non-relativistic models of nuclear reactions, and spin and color correlations in a quark-exchange model of nuclear matter. Highlights of recent research, vitae of principal investigators, and lists of publications and invited talks are also given. Recent research dealt primarily with medium-energy nuclear physics, relativistic theories of nuclei and the nuclear response, the nuclear equation of state under extreme conditions, the dynamics of the quark endash gluon plasma in relativistic heavy-ion collisions, and theories of the nucleon endash nucleon force

  20. Theoretical Computer Science

    DEFF Research Database (Denmark)

    2002-01-01

    The proceedings contains 8 papers from the Conference on Theoretical Computer Science. Topics discussed include: query by committee, linear separation and random walks; hardness results for neural network approximation problems; a geometric approach to leveraging weak learners; mind change...