Science.gov

Sample records for ideal atomic centre

  1. The virtual atomic and molecular data centre (VAMDC) consortium

    NASA Astrophysics Data System (ADS)

    Dubernet, M. L.; Antony, B. K.; Ba, Y. A.; Babikov, Yu L.; Bartschat, K.; Boudon, V.; Braams, B. J.; Chung, H.-K.; Daniel, F.; Delahaye, F.; Del Zanna, G.; de Urquijo, J.; Dimitrijević, M. S.; Domaracka, A.; Doronin, M.; Drouin, B. J.; Endres, C. P.; Fazliev, A. Z.; Gagarin, S. V.; Gordon, I. E.; Gratier, P.; Heiter, U.; Hill, C.; Jevremović, D.; Joblin, C.; Kasprzak, A.; Krishnakumar, E.; Leto, G.; Loboda, P. A.; Louge, T.; Maclot, S.; Marinković, B. P.; Markwick, A.; Marquart, T.; Mason, H. E.; Mason, N. J.; Mendoza, C.; Mihajlov, A. A.; Millar, T. J.; Moreau, N.; Mulas, G.; Pakhomov, Yu; Palmeri, P.; Pancheshnyi, S.; Perevalov, V. I.; Piskunov, N.; Postler, J.; Quinet, P.; Quintas-Sánchez, E.; Ralchenko, Yu; Rhee, Y.-J.; Rixon, G.; Rothman, L. S.; Roueff, E.; Ryabchikova, T.; Sahal-Bréchot, S.; Scheier, P.; Schlemmer, S.; Schmitt, B.; Stempels, E.; Tashkun, S.; Tennyson, J.; Tyuterev, Vl G.; Vujčić, V.; Wakelam, V.; Walton, N. A.; Zatsarinny, O.; Zeippen, C. J.; Zwölf, C. M.

    2016-04-01

    The Virtual Atomic and Molecular Data Centre (VAMDC) Consortium is a worldwide consortium which federates atomic and molecular databases through an e-science infrastructure and an organisation to support this activity. About 90% of the inter-connected databases handle data that are used for the interpretation of astronomical spectra and for modelling in many fields of astrophysics. Recently the VAMDC Consortium has connected databases from the radiation damage and the plasma communities, as well as promoting the publication of data from Indian institutes. This paper describes how the VAMDC Consortium is organised for the optimal distribution of atomic and molecular data for scientific research. It is noted that the VAMDC Consortium strongly advocates that authors of research papers using data cite the original experimental and theoretical papers as well as the relevant databases. .

  2. Atomic lenses and ideal single-photon detections

    NASA Astrophysics Data System (ADS)

    Li, Xingmin; Xie, Lingyun; Wei, L. F.

    2015-12-01

    Photon detector is one of the key units in the integrated optical devices. Due to the weak atom-photon interaction, the detection efficiency of a single photon by a bare atom (as a photon detector aside the waveguide) is relatively low (the most reachable value is shown as 50 % , which has being approached experimentally). In order to overcome such a limit, a pair of spatially separated two-level atoms (the photon lenses) with adjustable inflection and transmission coefficients of the photon are introduced to generate an atomic cavity, in which the detected probability of the waveguide photon by the single detector can be significantly enhanced (even reach to 100 % under certain conditions). The proposal is demonstrated specifically by a circuit QED system for highly effective detection of a single microwave photon.

  3. Updates to the Virtual Atomic and Molecular Data Centre

    NASA Astrophysics Data System (ADS)

    Hill, Christian; Tennyson, Jonathan; Gordon, Iouli E.; Rothman, Laurence S.; Dubernet, Marie-Lise

    2014-06-01

    The Virtual Atomic and Molecular Data Centre (VAMDC) has established a set of standards for the storage and transmission of atomic and molecular data and an SQL-based query language (VSS2) for searching online databases, known as nodes. The project has also created an online service, the VAMDC Portal, through which all of these databases may be searched and their results compared and aggregated. Since its inception four years ago, the VAMDC e-infrastructure has grown to encompass over 40 databases, including HITRAN, in more than 20 countries and engages actively with scientists in six continents. Associated with the portal are a growing suite of software tools for the transformation of data from its native, XML-based, XSAMS format, to a range of more convenient human-readable (such as HTML) and machinereadable (such as CSV) formats. The relational database for HITRAN1, created as part of the VAMDC project is a flexible and extensible data model which is able to represent a wider range of parameters than the current fixed-format text-based one. Over the next year, a new online interface to this database will be tested, released and fully documented - this web application, HITRANonline2, will fully replace the ageing and incomplete JavaHAWKS software suite.

  4. Strategic Leadership of Teaching and Learning Centres: From Reality to Ideal

    ERIC Educational Resources Information Center

    Palmer, Stuart; Holt, Dale; Challis, Di

    2011-01-01

    This paper reports on the third phase of a study of Australian Teaching and Learning Centres to identify factors that contribute to the effective strategic leadership of Centres. Focus groups at 10 Australian universities included 66 respondents, providing a diverse range of perspectives, from students to members of the university executive.…

  5. Strategic Leadership of Teaching and Learning Centres: From Reality to Ideal

    ERIC Educational Resources Information Center

    Palmer, Stuart; Holt, Dale; Challis, Di

    2011-01-01

    This paper reports on the third phase of a study of Australian Teaching and Learning Centres to identify factors that contribute to the effective strategic leadership of Centres. Focus groups at 10 Australian universities included 66 respondents, providing a diverse range of perspectives, from students to members of the university executive.…

  6. The Ideal and Real Gas Heat Capacity of Potassium Atoms at High Temperatures

    NASA Astrophysics Data System (ADS)

    Biolsi, Louis; Biolsi, Michael

    2016-04-01

    The ideal gas heat capacity, Cp, of potassium atoms is calculated to high temperatures using statistical mechanics. Since there are a large number of electronic energy levels in the partition function (Boltzmann sum) below the first ionization potential, the partition function and Cp will become very large as the temperature increases unless the number of energy levels contributing to the partition function is constrained. Two primary categories of arguments are used to do this. First, at high temperatures, the increased size of the atoms constrains the sum (Bethe method). Second, an argument based on the existence of interacting charged species at higher temperatures is used to constrain the sum (ionization potential lowering method). When potassium atoms are assumed to constitute a real gas that obeys the virial equation of state, the lowest non-ideal contribution to Cp depends on the second derivative of the second virial coefficient, B( T), which depends on the interaction potential energy curves between two potassium atoms. When two ground-state (2{S}) atoms interact, they can follow either of the two potential energy curves. When a 2{S} atom interacts with an atom in the first electronically excited (2{P}) state, they can follow any of the eight potential energy curves. The values of B( T) for the ten states are determined, then averaged, and used to calculate the nonideal contribution to Cp.

  7. The Ideal Gas and Real Gas Heat Capacity of Sodium Atoms

    NASA Astrophysics Data System (ADS)

    Biolsi, Louis

    2014-10-01

    The ideal gas heat capacity of sodium atoms in the vapor phase is calculated to high temperatures using statistical mechanics. Since there are, in principle, an infinite number of atomic energy levels, the partition function and the heat capacity will grow very large unless the summation over energy levels is constrained as temperature increases. At higher temperatures, the increasing size of the atoms, which is a consequence of the increased population of highly excited energy levels, is used as a mechanism for limiting the summation over energy levels. The "" and "Bethe" procedures for cutting off the summation over energy levels will be discussed, and the results obtained using the two methods will be compared. In addition, although experimental information is available about lower atomic energy levels and some theoretical calculations are available for excited energy levels, information is lacking for most individual atomic states associated with highly excited energy levels. A "fill" procedure for approximating the energy of the unknown states will be discussed. Sodium vapor will also be considered to be a real gas that obeys the virial equation of state. The first non-ideal term in the power series expansion of the heat capacity in terms of virial coefficients involves the second virial coefficient, . This depends on the interaction potential energy between two sodium atoms, i.e., the potential energy curves for the sodium dimer. Accurate interaction potential energies can be obtained from either experimental or theoretical information for the lowest ten electronic states of the sodium dimer. These are used to calculate for each state, and the averaged value of for all ten states is used to calculate the non-ideal contribution to the heat capacity of sodium atoms as a function of temperature.

  8. Atomic and Molecular Databases, VAMDC (Virtual Atomic and Molecular Data Centre)

    NASA Astrophysics Data System (ADS)

    Dubernet, Marie-Lise; Zwölf, Carlo Maria; Moreau, Nicolas; Awa Ba, Yaya; VAMDC Consortium

    2015-08-01

    The "Virtual Atomic and Molecular Data Centre Consortium",(VAMDC Consortium, http://www.vamdc.eu) is a Consortium bound by an Memorandum of Understanding aiming at ensuring the sustainability of the VAMDC e-infrastructure. The current VAMDC e-infrastructure inter-connects about 30 atomic and molecular databases with the number of connected databases increasing every year: some databases are well-known databases such as CDMS, JPL, HITRAN, VALD,.., other databases have been created since the start of VAMDC. About 90% of our databases are used for astrophysical applications. The data can be queried, retrieved, visualized in a single format from a general portal (http://portal.vamdc.eu) and VAMDC is also developing standalone tools in order to retrieve and handle the data. VAMDC provides software and support in order to include databases within the VAMDC e-infrastructure. One current feature of VAMDC is the constrained environnement of description of data that ensures a higher quality for distribution of data; a future feature is the link of VAMDC with evaluation/validation groups. The talk will present the VAMDC Consortium and the VAMDC e infrastructure with its underlying technology, its services, its science use cases and its etension towards other communities than the academic research community.

  9. Constructing the "Ideal" Family for Family-Centred Practice: Challenges for Delivery

    ERIC Educational Resources Information Center

    Dodd, Jenny; Saggers, Sherry; Wildy, Helen

    2009-01-01

    Family-centred practice positions families as the key decision-makers, central to and experts in the wants and needs of their child. This paper discusses how families interviewed for a Western Australian study describe their relationships with a range of allied health professionals in the paediatric disability sector. The allied health…

  10. Constructing the "Ideal" Family for Family-Centred Practice: Challenges for Delivery

    ERIC Educational Resources Information Center

    Dodd, Jenny; Saggers, Sherry; Wildy, Helen

    2009-01-01

    Family-centred practice positions families as the key decision-makers, central to and experts in the wants and needs of their child. This paper discusses how families interviewed for a Western Australian study describe their relationships with a range of allied health professionals in the paediatric disability sector. The allied health…

  11. Atomic force microscopy analysis of nanoparticles in non-ideal conditions

    PubMed Central

    2011-01-01

    Nanoparticles are often measured using atomic force microscopy or other scanning probe microscopy methods. For isolated nanoparticles on flat substrates, this is a relatively easy task. However, in real situations, we often need to analyze nanoparticles on rough substrates or nanoparticles that are not isolated. In this article, we present a simple model for realistic simulations of nanoparticle deposition and we employ this model for modeling nanoparticles on rough substrates. Different modeling conditions (coverage, relaxation after deposition) and convolution with different tip shapes are used to obtain a wide spectrum of virtual AFM nanoparticle images similar to those known from practice. Statistical parameters of nanoparticles are then analyzed using different data processing algorithms in order to show their systematic errors and to estimate uncertainties for atomic force microscopy analysis of nanoparticles under non-ideal conditions. It is shown that the elimination of user influence on the data processing algorithm is a key step for obtaining accurate results while analyzing nanoparticles measured in non-ideal conditions. PMID:21878120

  12. Site occupancy of interstitial deuterium atoms in face-centred cubic iron

    NASA Astrophysics Data System (ADS)

    Machida, Akihiko; Saitoh, Hiroyuki; Sugimoto, Hidehiko; Hattori, Takanori; Sano-Furukawa, Asami; Endo, Naruki; Katayama, Yoshinori; Iizuka, Riko; Sato, Toyoto; Matsuo, Motoaki; Orimo, Shin-Ichi; Aoki, Katsutoshi

    2014-09-01

    Hydrogen composition and occupation state provide basic information for understanding various properties of the metal-hydrogen system, ranging from microscopic properties such as hydrogen diffusion to macroscopic properties such as phase stability. Here the deuterization process of face-centred cubic Fe to form solid-solution face-centred cubic FeDx is investigated using in situ neutron diffraction at high temperature and pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å3 per deuterium atom. The minor occupation of the tetrahedral site is thermally driven by the intersite movement of deuterium atoms along the ‹111› direction in the face-centred cubic metal lattice.

  13. Two-Centre Convergent Close-Coupling Approach to Ion-Atom Collisions: Current Progress

    NASA Astrophysics Data System (ADS)

    Kadyrov, Alisher; Abdurakhmanov, Ilkhom; Bailey, Jackson; Bray, Igor

    2016-09-01

    There are two versions of the convergent close-coupling (CCC) approach to ion-atom collisions: quantum-mechanical (QM-CCC) and semi-classical (SC-CCC). Recently, both implementations have been extended to include electron-transfer channels. The SC-CCC approach has been applied to study the excitation and the electron-capture processes in proton-hydrogen collisions. The integral alignment parameter A20 for polarization of Lyman- α emission and the cross sections for excitation and electron-capture into the lowest excited states have been calculated for a wide range of the proton impact energies. It has been established that for convergence of the results a very wide range of impact parameters (typically, 0-50 a.u.) is required due to extremely long tails of transition probabilities for transitions into the 2 p states at high energies. The QM-CCC approach allowed to obtain an accurate solution of proton-hydrogen scattering problem including all underlying processes, namely, direct scattering and ionisation, and electron capture into bound and continuum states of the projectile. In this presentation we give a general overview of current progress in applications of the two-centre CCC approach to ion-atom and atom-atom collisions. The work is supported by the Australian Research Council.

  14. The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC

    NASA Astrophysics Data System (ADS)

    Endres, Christian P.; Schlemmer, Stephan; Schilke, Peter; Stutzki, Jürgen; Müller, Holger S. P.

    2016-09-01

    The Cologne Database for Molecular Spectroscopy, CDMS, was founded 1998 to provide in its catalog section line lists of mostly molecular species which are or may be observed in various astronomical sources (usually) by radio astronomical means. The line lists contain transition frequencies with qualified accuracies, intensities, quantum numbers, as well as further auxiliary information. They have been generated from critically evaluated experimental line lists, mostly from laboratory experiments, employing established Hamiltonian models. Separate entries exist for different isotopic species and usually also for different vibrational states. As of December 2015, the number of entries is 792. They are available online as ascii tables with additional files documenting information on the entries. The Virtual Atomic and Molecular Data Centre, VAMDC, was founded more than 5 years ago as a common platform for atomic and molecular data. This platform facilitates exchange not only between spectroscopic databases related to astrophysics or astrochemistry, but also with collisional and kinetic databases. A dedicated infrastructure was developed to provide a common data format in the various databases enabling queries to a large variety of databases on atomic and molecular data at once. For CDMS, the incorporation in VAMDC was combined with several modifications on the generation of CDMS catalog entries. Here we introduce related changes to the data structure and the data content in the CDMS. The new data scheme allows us to incorporate all previous data entries but in addition allows us also to include entries based on new theoretical descriptions. Moreover, the CDMS entries have been transferred into a mySQL database format. These developments within the VAMDC framework have in part been driven by the needs of the astronomical community to be able to deal efficiently with large data sets obtained with the Herschel Space Telescope or, more recently, with the Atacama Large

  15. Effects of non-idealities and quantization of the center of mass motion on symmetric and asymmetric collective states in a collective state atomic interferometer

    NASA Astrophysics Data System (ADS)

    Sarkar, Resham; Kim, May E.; Fang, Renpeng; Tu, Yanfei; Shahriar, Selim M.

    2015-09-01

    We investigate the behavior of an ensemble of ? non-interacting, identical atoms excited by a laser. In general, the ?-th atom sees a Rabi frequency ?, an initial position dependent laser phase ?, and a motion induced Doppler shift of ?. When ? or ? is distinct for each atom, the system evolves into a superposition of ? intercoupled states, of which there are ? symmetric and ? asymmetric collective states. For a collective state atomic interferometer (COSAIN), we recently proposed, it is important to understand the behavior of all the collective states under various conditions. In this paper, we show how to formulate the properties of these states under various non-idealities, and use this formulation to understand the dynamics thereof. We also consider the effect of treating the center of mass degree of freedom of the atoms quantum mechanically on the description of the collective states, illustrating that it is indeed possible to construct a generalized collective state, as needed for the COSAIN, when each atom is assumed to be in a localized wave packet. The analysis presented in this paper is important for understanding the dynamics of the COSAIN, and will help advance the analysis and optimization of spin squeezing in the presence of practically unavoidable non-idealities as well as in the domain where the center of mass motion of the atoms is quantized.

  16. On the rotational spectra of endohedral atoms at fullerenes: the off-centre case

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1995-05-01

    A simple Hamiltonian describing the rotational dynamics of endohedral off-center atoms at fullerenes is reported. Using this Hamiltonian rotational spectra for Li +@C 60 are calculated and the effect of the angular dependence of the atom-cage potential energy on such spectra is evaluated. Complexity, large density of transitions and the appearance of rotational oscillations and librational bands are the main features of the calculated spectra.

  17. On ideals and idealization.

    PubMed

    Morrison, Andrew P

    2009-04-01

    This chapter repositions ideals away from their role as defensive structures restraining aggressive and lustful drives (as traditionally viewed) toward their place in shaping creativity and love. We select and mold our particular ideals in providing meaning and in this manner help to create those selfobjects needed to resolve or soothe our needs. This creative process may include "reshaping" of the available object to represent the "idealized other." From this perspective, Kohut's view of idealization and the idealized parental imago will be considered, including my own notion of a one-and-a-half person psychology. Our ideals inevitably conflict and clash, leading to internal self-conflicts that generate what I call the dialectic of narcissism. Narcissism is here considered broadly, reflecting all attributes of self-experience. Shame plays an important role in this dialectic, relating to failure with regard to ideals and to falling short of cherished goals. Ultimately, it is the shaping of, and approximation to, flexible and meaningful ideals that comprise that lofty, ineffable, human ideal--wisdom. Clinical vignettes will be offered to illustrate these themes.

  18. Atom-Photon Coupling from Nitrogen-vacancy Centres Embedded in Tellurite Microspheres

    NASA Astrophysics Data System (ADS)

    Ruan, Yinlan; Gibson, Brant C.; Lau, Desmond W. M.; Greentree, Andrew D.; Ji, Hong; Ebendorff-Heidepriem, Heike; Johnson, Brett C.; Ohshima, Takeshi; Monro, Tanya M.

    2015-06-01

    We have developed a technique for creating high quality tellurite microspheres with embedded nanodiamonds (NDs) containing nitrogen-vacancy (NV) centres. This hybrid method allows fluorescence of the NVs in the NDs to be directly, rather than evanescently, coupled to the whispering gallery modes of the tellurite microspheres at room temperature. As a demonstration of its sensing potential, shifting of the resonance peaks is also demonstrated by coating a sphere surface with a liquid layer. This new approach is a robust way of creating cavities for use in quantum and sensing applications.

  19. Calibration of a new experimental chamber for PIXE analysis at the Accelerator Facilities Division of Atomic Energy Centre Dhaka (AECD)

    NASA Astrophysics Data System (ADS)

    Hassan, Md. Taufique; Shariff, Md. Asad; Hossein, Amzad; Abedin, Md. Joynal; Fazlul Hoque, A. K. M.; Chowdhuri, M. S.

    2015-05-01

    A new experimental chamber has been installed at the 3 MV Van de Graaff Accelerator Facilities Division in the Atomic Energy Centre, Dhaka, to perform different Ion Beam Analysis (IBA) techniques. The calibration of this new setup for Particle Induced X-ray Emission (PIXE) technique has been done using a set of thin MicroMatter standards and GUPIX (PIXE spectrum analysis software), which is explicated in this paper. The effective thicknesses of the beryllium window of the X-ray detector and of the different absorbers used were determined. For standardization, the so called instrumental constant H (product of detector solid angle and the correction factor for the setup) as function of X-ray energy were determined and stored inside the GUPIX library for further PIXE analysis.

  20. Cdms 2012: a Database Within the Framework of the Virtual Atomic and Molecular Data Centre - Recent Developments

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Endres, C. P.; Stutzki, J.; Schlemmer, S.

    2012-06-01

    The catalog section of the Cologne Database for Molecular Spectroscopy, CDMS, contains experimental and calculated transition frequencies of molecules and atoms observable by radioastronomical means with information on uncertainties, intensities and quantum numbers. Initially constructed as ascii tables, its inclusion into a database environment within the framework of the European Framework Programme 7 project Virtual Atomic and Molecular Data Centre (VAMDC) has begun in June 2008. The conversion required time because of the extensive content of the CDMS, the desire to maintain the existing functionality, the additional requisites as part of the VAMDC framework, and the sustained development of the VAMDC infrastructure. The new CDMS is scheduled to be available publicly prior to this conference; the old CDMS will be accessible for a transitional period. We will present some of the new CDMS features, provide some overview on new or updated entries from our last account three years ago as well as activities in other sections of the CDMS. Internet address: http://www.astro.uni-koeln.de/cdms/ H. S. P. Müller, F. Schlöder, J. Stutzki, and G. Winnewisser, J. Mol. Struct. 742, 215-227 (2005) H. S. P. Müller, S. Thorwirth, D. A. Roth, and G. Winnewisser, Astron. Astrophys. 370, L49-L52 (2001) Internet address: http://www.vamdc.org/ H. S. P. Müller, J. Stutzki, S. Schlemmer, contribution WH07, presented at the 64th International Symposium on Molecular Spectroscopy, Columbus, OH, USA, 2009

  1. Atomic Force Microscopy Study of an Ideally Hard Contact: The Diamond{bold (}111{bold )}/Tungsten Carbide Interface

    SciTech Connect

    Enachescu, M.; van den Oetelaar, R.J.; Carpick, R.W.; Ogletree, D.F.; Flipse, C.F.; Salmeron, M.

    1998-08-01

    A comprehensive nanotribological study of a hydrogen-terminated diamond(111)/tungsten carbide interface has been performed using ultrahigh vacuum atomic force microscopy. Both contact conductance, which is proportional to contact area, and friction have been measured as a function of applied load. We demonstrate for the first time that the load dependence of the contact area in UHV for this extremely hard single asperity contact is described by the Derjaguin-M{umlt u}ller-Toporov continuum mechanics model. Furthermore, the frictional force is found to be directly proportional to the contact area. {copyright} {ital 1998} {ital The American Physical Society}

  2. A molecular dynamics study of the effect of thermal boundary conductance on thermal transport of ideal crystal of n-alkanes with different number of carbon atoms

    SciTech Connect

    Rastgarkafshgarkolaei, Rouzbeh; Zeng, Yi; Khodadadi, J. M.

    2016-05-28

    Phase change materials such as n-alkanes that exhibit desirable characteristics such as high latent heat, chemical stability, and negligible supercooling are widely used in thermal energy storage applications. However, n-alkanes have the drawback of low thermal conductivity values. The low thermal conductivity of n-alkanes is linked to formation of randomly oriented nano-domains of molecules in their solid structure that is responsible for excessive phonon scattering at the grain boundaries. Thus, understanding the thermal boundary conductance at the grain boundaries can be crucial for improving the effectiveness of thermal storage systems. The concept of the ideal crystal is proposed in this paper, which describes a simplified model such that all the nano-domains of long-chain n-alkanes are artificially aligned perfectly in one direction. In order to study thermal transport of the ideal crystal of long-chain n-alkanes, four (4) systems (C{sub 20}H{sub 42}, C{sub 24}H{sub 50}, C{sub 26}H{sub 54}, and C{sub 30}H{sub 62}) are investigated by the molecular dynamics simulations. Thermal boundary conductance between the layers of ideal crystals is determined using both non-equilibrium molecular dynamics (NEMD) and equilibrium molecular dynamics (EMD) simulations. Both NEMD and EMD simulations exhibit no significant change in thermal conductance with the molecular length. However, the values obtained from the EMD simulations are less than the values from NEMD simulations with the ratio being nearly three (3) in most cases. This difference is due to the nature of EMD simulations where all the phonons are assumed to be in equilibrium at the interface. Thermal conductivity of the n-alkanes in three structures including liquid, solid, and ideal crystal is investigated utilizing NEMD simulations. Our results exhibit a very slight rise in thermal conductivity values as the number of carbon atoms of the chain increases. The key understanding is that thermal transport can be

  3. A molecular dynamics study of the effect of thermal boundary conductance on thermal transport of ideal crystal of n-alkanes with different number of carbon atoms

    NASA Astrophysics Data System (ADS)

    Rastgarkafshgarkolaei, Rouzbeh; Zeng, Yi; Khodadadi, J. M.

    2016-05-01

    Phase change materials such as n-alkanes that exhibit desirable characteristics such as high latent heat, chemical stability, and negligible supercooling are widely used in thermal energy storage applications. However, n-alkanes have the drawback of low thermal conductivity values. The low thermal conductivity of n-alkanes is linked to formation of randomly oriented nano-domains of molecules in their solid structure that is responsible for excessive phonon scattering at the grain boundaries. Thus, understanding the thermal boundary conductance at the grain boundaries can be crucial for improving the effectiveness of thermal storage systems. The concept of the ideal crystal is proposed in this paper, which describes a simplified model such that all the nano-domains of long-chain n-alkanes are artificially aligned perfectly in one direction. In order to study thermal transport of the ideal crystal of long-chain n-alkanes, four (4) systems (C20H42, C24H50, C26H54, and C30H62) are investigated by the molecular dynamics simulations. Thermal boundary conductance between the layers of ideal crystals is determined using both non-equilibrium molecular dynamics (NEMD) and equilibrium molecular dynamics (EMD) simulations. Both NEMD and EMD simulations exhibit no significant change in thermal conductance with the molecular length. However, the values obtained from the EMD simulations are less than the values from NEMD simulations with the ratio being nearly three (3) in most cases. This difference is due to the nature of EMD simulations where all the phonons are assumed to be in equilibrium at the interface. Thermal conductivity of the n-alkanes in three structures including liquid, solid, and ideal crystal is investigated utilizing NEMD simulations. Our results exhibit a very slight rise in thermal conductivity values as the number of carbon atoms of the chain increases. The key understanding is that thermal transport can be significantly altered by how the molecules and the

  4. In situ atomic-scale observation of twinning-dominated deformation in nanoscale body-centred cubic tungsten

    NASA Astrophysics Data System (ADS)

    Wang, Jiangwei; Zeng, Zhi; Weinberger, Christopher R.; Zhang, Ze; Zhu, Ting; Mao, Scott X.

    2015-06-01

    Twinning is a fundamental deformation mode that competes against dislocation slip in crystalline solids. In metallic nanostructures, plastic deformation requires higher stresses than those needed in their bulk counterparts, resulting in the ‘smaller is stronger’ phenomenon. Such high stresses are thought to favour twinning over dislocation slip. Deformation twinning has been well documented in face-centred cubic (FCC) nanoscale crystals. However, it remains unexplored in body-centred cubic (BCC) nanoscale crystals. Here, by using in situ high-resolution transmission electron microscopy and atomistic simulations, we show that twinning is the dominant deformation mechanism in nanoscale crystals of BCC tungsten. Such deformation twinning is pseudoelastic, manifested through reversible detwinning during unloading. We find that the competition between twinning and dislocation slip can be mediated by loading orientation, which is attributed to the competing nucleation mechanism of defects in nanoscale BCC crystals. Our work provides direct observations of deformation twinning as well as new insights into the deformation mechanism in BCC nanostructures.

  5. Kinematic rotations for four-centre reactions: mapping tetra-atomic potential energy surfaces on the kinetic sphere

    NASA Astrophysics Data System (ADS)

    Aquilanti, Vincenzo; Bonnet, Laurent; Cavalli, Simonetta

    Kinematic rotations for four body processes canbe conveniently represented as arcs connecting the different reactive rearrangements, (T + UVW, TU + VW, TUV + W and all permutations). The arcs can be considered as forming great circles on a sphere, which is therefore a convenient manifold for setting up symmetric coordinates in asymptotic rearrangement channels: in the particular cases where the reactions are collinearly dominated, the sphere provides the full chart for the (fixed moment of inertia or hyperradial) mapping of the potential energy surface. Also,the representations can be extended to include connections to a formulation where two particles are symmetrically treated with respect to a third one-as introduced in the Journal of Chemical Physics (1986, 85, 1355)-and to encompass the asymptotic situation of the four body system decomposing into three fragments (T + U + VW, T + UV + W, etc...). Comments are made on other cases pertaining to the symmetric parametrizations of four centre processes.

  6. CH_4, C_2H_4, SF_6 and CF_4 Calculated Spectroscopic Databases for the Virtual Atomic and Molecular Data Centre

    NASA Astrophysics Data System (ADS)

    Boudon, Vincent; Wenger, Christian; Surleau, Romain; Louviot, Maud; Faye, Mbaye; Rotger, Maud; Daumont, Ludovic; Bonhommeau, David A.; Tyuterev, Vladimir; Ba, Yaye Awa; Dubernet, Marie-Lise

    2014-06-01

    Two spectroscopic relational databases, denoted MeCaSDa and ECaSDa, have been implemented for methane and ethene, and included in VAMDC (Virtual Atomic and Molecular Data Centre, http://portal.vamdc.eu/vamdc_portal/home.seam) [1]. These databases collect calculated spectroscopic data from the accurate analyses previously performed for the electronic ground state of methane, ethene, and some of their isotopologues: 12CH_4, 13CH_4, and 12C_2H_4 [2]. Both infrared absorption and Raman scattering lines are included. The polyad structures are reported and the transitions are precisely described by their energy, their intensity and the full description of the lower and upper states involved in the transitions. Very recently, we also built on the same model two new databases, named SHeCaSDa and TFMeCaSDa for the SF_6 and CF_4 greenhouse gas molecules, respectively. The relational schemas of these four databases are equivalent and optimized to enable the better compromise between data retrieval and compatibility with the XSAMS (XML Schema for Atoms, Molecules, and Solids) format adopted within the VAMDC European project. [1] Y. A. Ba, Ch. Wenger et al., J. Quant. Spectrosc. Radiat. Transfer, 130, 62 (2013). [2] M.-L. Dubernet, V. Boudon et al., J. Quant. Spectrosc. Radiat. Transfer, 111, 2151 (2010).

  7. Anhydrous TEMPO-H: reactions of a good hydrogen atom donor with low-valent carbon centres.

    PubMed

    Giffin, Nick A; Makramalla, Miller; Hendsbee, Arthur D; Robertson, Katherine N; Sherren, Cody; Pye, Cory C; Masuda, Jason D; Clyburne, Jason A C

    2011-05-21

    In this paper, we report a novel synthesis of anhydrous 1-hydroxy-2,2,6,6-tetramethyl-piperidine (TEMPO-H). An X-ray crystal structure and full characterization of the compound are included. Compared to hydrated TEMPO-H, its anhydrous form exhibits improved stability and a differing chemical reactivity. The reactions of anhydrous TEMPO-H with a variety of low-valent carbon centres are described. For example, anhydrous TEMPO-H was reacted with 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), an unsaturated NHC. Crystals of [CHNC(6)H(2)(CH(3))(3)](2)C···HO(NC(5)H(6)(CH(3))(4)), IMes···TEMPO-H, were isolated and a crystal structure determined. The experimental structure is compared to the results of theoretical calculations on the hydrogen-bonded dimer. Anhydrous TEMPO-H was also reacted with the saturated NHC, 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene (SIPr), giving the product [CH(2)Ni-Pr(2)C(6)H(3)](2)CH···O(NC(5)H(6)(CH(3))(4)). In contrast, the reaction of hydrated TEMPO-H with 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene gave small amounts of the hydrolysis product, N-(2,6-diisopropylphenyl)-N-[2-(2,6-diisopropylphenylamino)ethyl]formamide. Finally, anhydrous TEMPO-H was reacted with (triphenylphosphoranylidene)ketene to generate Ph(3)PC(H)C(=O)O(NC(5)H(6)(CH(3))(4)). A full characterization of the product, including an X-ray crystal structure, is described.

  8. Force correcting atom centred potentials for generalised gradient approximated density functional theory: Approaching hybrid functional accuracy for geometries and harmonic frequencies in small chlorofluorocarbons

    NASA Astrophysics Data System (ADS)

    Anatole von Lilienfeld, O.

    2013-08-01

    Generalised gradient approximated (GGA) density functional theory (DFT) typically overestimates polarisability and bond-lengths, and underestimates force constants of covalent bonds. To overcome this problem we show that one can use empirical force correcting atom centred potentials (FCACPs), parametrised for every nuclear species. Parameters are obtained through minimisation of a penalty functional that explicitly encodes hybrid DFT forces and static polarisabilities of reference molecules. For hydrogen, fluorine, chlorine and carbon the respective reference molecules consist of H2, F2, Cl2 and CH4. The transferability of this approach is assessed for harmonic frequencies in a small set of chlorofluorocarbon molecules. Numerical evidence, gathered for CF4, CCl4, CCl3F, CCl2F2, CClF3, ClF, HF, HCl, CFH3, CF2H2, CF3H, CHCl3, CH2Cl2 and CH3Cl indicates that the GGA+FCACP level of theory yields harmonic frequencies that are significantly more consistent with hybrid DFT values, as well as slightly reduced molecular polarisability.

  9. Sex Education and Ideals

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.; Spiecker, Ben

    2008-01-01

    This article argues that sex education should include sexual ideals. Sexual ideals are divided into sexual ideals in the strict sense and sexual ideals in the broad sense. It is argued that ideals that refer to the context that is deemed to be most ideal for the gratification of sexual ideals in the strict sense are rightfully called sexual…

  10. Sex Education and Ideals

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.; Spiecker, Ben

    2008-01-01

    This article argues that sex education should include sexual ideals. Sexual ideals are divided into sexual ideals in the strict sense and sexual ideals in the broad sense. It is argued that ideals that refer to the context that is deemed to be most ideal for the gratification of sexual ideals in the strict sense are rightfully called sexual…

  11. Chalcogenide centred gold complexes.

    PubMed

    Gimeno, M Concepción; Laguna, Antonio

    2008-09-01

    Chalcogenide-centred gold complexes are an important class of compounds in which a central chalcogen is surrounded by several gold atoms or gold and other metals. They have special characteristics such as unusual geometries, electron deficiency and properties such as luminescence or non-linear optical properties. The best known species are the trinuclear [E(AuPR3)3]+, 'oxonium' type species, that have high synthetic applicability, not only in other chalcogen-centred species, but in many other organometallic derivatives. The aurophilic interactions play an important role in the stability, preference for a particular geometry and luminescence properties in this type of derivatives (critical review, 117 references).

  12. Mol-D a Database and a Web Service within the Serbian Virtual Observatory and the Virtual Atomic and Molecular Data Centre

    NASA Astrophysics Data System (ADS)

    Srećković, Vladimir A.; Jevremović, Darko; Vujčić, Veljko; Ignjatović, Ljubinko M.; Milovanović, Nenad; Erkapić, Sanja; Dimitrijević, Milan S.

    2017-06-01

    In this contribution we report the current stage of the MOLecular Dissociation (MOL-D) database which is a web service within the Serbian virtual observatory (SerVO) and node within Virtual Atomic and Molecular Data Center (VAMDC). MOL-D is an atomic and molecular (A&M) database devoted to the modelling of stellar atmospheres, laboratory plasmas, industrial plasmas etc. The initial stage of development was done at the end of 2014, when the service for data connected with hydrogen and helium molecular ions was done. In the next stage of the development of MOL-D, we include new cross-sections and rate coefficients for processes which involve species such as XH+, where X is atom of some metal. Data are important for the exploring of the interstellar medium as well as for the early Universe chemistry and for the modeling of stellar and solar atmospheres. In this poster, we present our ongoing work and plans for the future.

  13. Ideals and Category Typicality

    ERIC Educational Resources Information Center

    Kim, ShinWoo; Murphy, Gregory L.

    2011-01-01

    Barsalou (1985) argued that exemplars that serve category goals become more typical category members. Although this claim has received support, we investigated (a) whether categories have a single ideal, as negatively valenced categories (e.g., cigarette) often have conflicting goals, and (b) whether ideal items are in fact typical, as they often…

  14. Ideals and Category Typicality

    ERIC Educational Resources Information Center

    Kim, ShinWoo; Murphy, Gregory L.

    2011-01-01

    Barsalou (1985) argued that exemplars that serve category goals become more typical category members. Although this claim has received support, we investigated (a) whether categories have a single ideal, as negatively valenced categories (e.g., cigarette) often have conflicting goals, and (b) whether ideal items are in fact typical, as they often…

  15. Ideal female brow aesthetics.

    PubMed

    Griffin, Garrett R; Kim, Jennifer C

    2013-01-01

    The concept of the ideal female eyebrow has changed over time. Modern studies examining youthful brow aesthetics are reviewed. An analysis of ideal female brow characteristics as depicted in the Western print media between 1945 and 2011 was performed. This analysis provided objective evidence that the ideal youthful brow peak has migrated laterally over time to lie at the lateral canthus. There has been a nonstatistically significant trend toward lower and flatter brows. These findings are discussed in relation to current concepts of female brow aging, with repercussions regarding endoscopic brow lift and aesthetic forehead surgery.

  16. Ideals in intimate relationships.

    PubMed

    Fletcher, G J; Simpson, J A; Thomas, G; Giles, L

    1999-01-01

    This research examined lay relationship and partner ideals in romantic relationships from both a social-cognitive and an evolutionary perspective. Studies 1 and 2 revealed that the qualities of an ideal partner were represented by 3 factors (partner warmth-trustworthiness, vitality-attractiveness, and status-resources), whereas the qualities of an ideal relationship were represented by 2 factors (relationship intimacy-loyalty and passion). A confirmatory factor analysis in Study 3 replicated these factor structures but found considerable overlap across the partner and relationship dimensions. Studies 4 and 5 produced convergent and discriminant validity evidence for all 5 factors. Study 6 indicated that the higher the consistency between the ideals and related assessments of the current partner and relationship, the more positively the current relationship was evaluated.

  17. Developmental Idealism in China

    PubMed Central

    Thornton, Arland; Xie, Yu

    2016-01-01

    This paper examines the intersection of developmental idealism with China. It discusses how developmental idealism has been widely disseminated within China and has had enormous effects on public policy and programs, on social institutions, and on the lives of individuals and their families. This dissemination of developmental idealism to China began in the 19th century, when China met with several military defeats that led many in the country to question the place of China in the world. By the beginning of the 20th century, substantial numbers of Chinese had reacted to the country’s defeats by exploring developmental idealism as a route to independence, international respect, and prosperity. Then, with important but brief aberrations, the country began to implement many of the elements of developmental idealism, a movement that became especially important following the assumption of power by the Communist Party of China in 1949. This movement has played a substantial role in politics, in the economy, and in family life. The beliefs and values of developmental idealism have also been directly disseminated to the grassroots in China, where substantial majorities of Chinese citizens have assimilated them. These ideas are both known and endorsed by very large numbers in China today. PMID:28316833

  18. Developmental Idealism in China.

    PubMed

    Thornton, Arland; Xie, Yu

    2016-10-01

    This paper examines the intersection of developmental idealism with China. It discusses how developmental idealism has been widely disseminated within China and has had enormous effects on public policy and programs, on social institutions, and on the lives of individuals and their families. This dissemination of developmental idealism to China began in the 19(th) century, when China met with several military defeats that led many in the country to question the place of China in the world. By the beginning of the 20(th) century, substantial numbers of Chinese had reacted to the country's defeats by exploring developmental idealism as a route to independence, international respect, and prosperity. Then, with important but brief aberrations, the country began to implement many of the elements of developmental idealism, a movement that became especially important following the assumption of power by the Communist Party of China in 1949. This movement has played a substantial role in politics, in the economy, and in family life. The beliefs and values of developmental idealism have also been directly disseminated to the grassroots in China, where substantial majorities of Chinese citizens have assimilated them. These ideas are both known and endorsed by very large numbers in China today.

  19. Idealization and empirical testing

    NASA Astrophysics Data System (ADS)

    Shaffer, Michael John

    It has been argued that the presence of idealizations in physical theories implies that scientific realism is false. Furthermore, it has also been argued that because physical theories incorporate idealizations scientific theories must be accepted a priori, because the objects, processes, etc. quantified over in such expressions cannot be observed in the actual world. I argue against the former view by showing that scientific realism is compatible with the fact that all theoretical claims depend on idealizing assumptions, at least when such claims are properly regimented as a special kind of counterfactual conditional. To this end a logic incorporating such conditionals, VCP, is constructed and given a semantic basis. Given VCP, the latter problem is considered in light of extant theories of confirmation, and all are found to be incapable of dealing with the acceptance of theoretical claims that depend on idealizing assumptions. In addressing this problem it is also shown that a new problem arises for subjective Bayesians concerning prior probabilities of theoretical claims that depend on idealizing assumptions. Insofar as I claim that all theoretical claims depend on idealizing assumptions, this problem for Bayesian confirmation theory appears to be quite serious. I conclude that only inference to the best explanation, when understood in terms of VCP, can provide a rational basis for the empirical acceptance of such theoretical claims.

  20. The Ideal Academy.

    ERIC Educational Resources Information Center

    Jervis, Jane L.

    1995-01-01

    This article discusses the faculty appointment system at Evergreen State College (Washington), which does not have tenure, academic departments, or academic ranks, in light of an ideal system that might have a core of long-term faculty supplemented by short-term faculty. It considers the need to balance institutional flexibility with faculty…

  1. The ideal fluid.

    PubMed

    Russell, Lyndal; McLean, Anthony S

    2014-08-01

    The characteristics of an ideal intravenous fluid in the critically ill patient are discussed. Intravenous fluids are the most frequent drug administered to patients. Questioning the use of commonly administered intravenous fluids has resulted in an increased focus on their efficacy and safety. Discrimination between fluids currently in use has been the central theme of many recent large studies, and emerging from these findings is an understanding of characteristics that would make for an ideal fluid for critically ill patients. There is increased morbidity and mortality with high chloride-containing crystalloid solutions and hydroxyethyl starch preparations, with resultant international governmental agency warnings regarding hydroxyethyl starch . The ideal fluid is one which achieves the aim of administration while minimizing or negating adverse effects, is inexpensive, and sufficiently stable when stored to be used in a wide range of clinical settings. The ideal fluid currently does not exist. Of existing options, use of hydroxyethyl starches and high chloride-containing crystalloid solutions should be discouraged. There is a lack of direct evidence that a balanced crystalloid solution confers benefit, however, the trend of recent data would support future investigation into the advantage of balanced solution over 0.9% saline.

  2. The Ideal Promotion Effort.

    ERIC Educational Resources Information Center

    Morris, Edward L.

    The ideal promotional effort for an educational television (ETV) station is dependent on a professional approach to the problem. This means that each ETV station should employ a public relations manager and should keep him informed about all major station decisions. The Public Broadcasting Service (PBS) has a campaign of its own to bring attention…

  3. The Ideal Academy.

    ERIC Educational Resources Information Center

    Jervis, Jane L.

    1995-01-01

    This article discusses the faculty appointment system at Evergreen State College (Washington), which does not have tenure, academic departments, or academic ranks, in light of an ideal system that might have a core of long-term faculty supplemented by short-term faculty. It considers the need to balance institutional flexibility with faculty…

  4. Quaternions and ideal flows

    NASA Astrophysics Data System (ADS)

    Eshraghi, H.; Gibbon, J. D.

    2008-08-01

    After a review of some of the recent works by Holm and Gibbon on quaternions and their application to Lagrangian flows, particularly the incompressible Euler equations and the equations of ideal MHD, this paper investigates the compressible and relativistic Euler equations using these methods.

  5. Ideal Integrating Bolometer

    NASA Technical Reports Server (NTRS)

    Kogut, A.; DiPirro, M.; Moseley, S. H.

    2004-01-01

    We describe a new "ideal integrator" bolometer as a prototype for a new generation of sensitive, flexible far-IR detectors suitable for use in large arrays. The combination of a non-dissipative sensor coupled with a fast heat switch provides breakthrough capabilities in both sensitivity and operation. The bolometer temperature varies linearly with the integrated infrared power incident on the detector, and may be sampled intermittently without loss of information between samples. The sample speed and consequent dynamic range depend only on the heat switch reset cycle and can be selected in software. Between samples, the device acts as an ideal integrator with noise significantly lower than resistive bolometers. Since there is no loss of information between samples, the device is well-suited for large arrays. A single SQUID readout could process an entire column of detectors, greatly reducing the complexity, power requirements, and cost of readout electronics for large pixel arrays.

  6. Delivering ideal employee experiences.

    PubMed

    Weiss, Marjorie D; Tyink, Steve; Kubiak, Curt

    2009-05-01

    Employee-centric strategies have moved from employee satisfaction and brand awareness to employee "affinity" or "attachment." In today's marketplace, occupational health nurses understand that differentiation (i.e., the perception of uniqueness) is the direct result of superior employee interactions, which lead to better employee care, enduring employee relationships, loyal employees, and satisfied employers. What drives employees to occupational health nurse attachment? The answer is a passion for rising above the competition to create ideal employee experiences.

  7. Capturing medical students' idealism.

    PubMed

    Smith, Janice K; Weaver, Donna B

    2006-01-01

    Students' idealism and desire to work with underserved populations decline as they progress from preclinical training through clerkships and residency. With an increasingly diverse population and increasing health disparities, academic health centers need to incorporate changes in their curricula to train socially responsible and idealistic physicians. International electives can provide valuable learning experiences to help achieve these goals. Sixty-six preclinical medical students at the University of Texas Medical Branch participated in an international elective from 1997 to 2005. After 1 week of didactics, they spent 3 weeks as part of a multidisciplinary medical team in rural Nicaragua. Postelective questionnaires were administered. From students' responses, we identified common learning themes and grouped them under the categories of attitudes, awareness, and skills. Limitations included a self-selection bias, lack of a control group, and limited follow-up. After the elective, students had an increased interest in volunteerism, humanitarian efforts, and working with underserved populations both in the United States and abroad, as well as more compassion toward the underserved. Students also reported a heightened awareness of social determinants of health and public health, and a broadened global perspective, as well as increased self-awareness. Our findings illustrate that a well-structured, mentored experience in international health can have a positive impact on preclinical students' attitudes, including their compassion, volunteerism, and interest in serving under-served populations, all measures of idealism.

  8. Capturing Medical Students’ Idealism

    PubMed Central

    Smith, Janice K.; Weaver, Donna B.

    2006-01-01

    PURPOSE Students’ idealism and desire to work with underserved populations decline as they progress from preclinical training through clerkships and residency. With an increasingly diverse population and increasing health disparities, academic health centers need to incorporate changes in their curricula to train socially responsible and idealistic physicians. International electives can provide valuable learning experiences to help achieve these goals. METHODS Sixty-six preclinical medical students at the University of Texas Medical Branch participated in an international elective from 1997 to 2005. After 1 week of didactics, they spent 3 weeks as part of a multidisciplinary medical team in rural Nicaragua. Postelective questionnaires were administered. From students’ responses, we identified common learning themes and grouped them under the categories of attitudes, awareness, and skills. Limitations included a self-selection bias, lack of a control group, and limited follow-up. RESULTS After the elective, students had an increased interest in volunteerism, humanitarian efforts, and working with underserved populations both in the United States and abroad, as well as more compassion toward the underserved. Students also reported a heightened awareness of social determinants of health and public health, and a broadened global perspective, as well as increased self-awareness. CONCLUSIONS Our findings illustrate that a well-structured, mentored experience in international health can have a positive impact on preclinical students’ attitudes, including their compassion, volunteerism, and interest in serving under-served populations, all measures of idealism. PMID:17003160

  9. Traces, ideals, and arithmetic means

    PubMed Central

    Kaftal, Victor; Weiss, Gary

    2002-01-01

    This article grew out of recent work of Dykema, Figiel, Weiss, and Wodzicki (Commutator structure of operator ideals) which inter alia characterizes commutator ideals in terms of arithmetic means. In this paper we study ideals that are arithmetically mean (am) stable, am-closed, am-open, soft-edged and soft-complemented. We show that many of the ideals in the literature possess such properties. We apply these notions to prove that for all the ideals considered, the linear codimension of their commutator space (the “number of traces on the ideal”) is either 0, 1, or ∞. We identify the largest ideal which supports a unique nonsingular trace as the intersection of certain Lorentz ideals. An application to elementary operators is given. We study properties of arithmetic mean operations on ideals, e.g., we prove that the am-closure of a sum of ideals is the sum of their am-closures. We obtain cancellation properties for arithmetic means: for principal ideals, a necessary and sufficient condition for first order cancellations is the regularity of the generator; for second order cancellations, sufficient conditions are that the generator satisfies the exponential Δ2-condition or is regular. We construct an example where second order cancellation fails, thus settling an open question. We also consider cancellation properties for inclusions. And we find and use lattice properties of ideals associated with the existence of “gaps.” PMID:12032287

  10. Science Learning Centres Roundup

    ERIC Educational Resources Information Center

    Education in Science, 2010

    2010-01-01

    The national network of Science Learning Centres aims to raise the quality of science teaching from Key Stage 1 through post-16 (ages 5-19). Short courses are provided locally through the regional Science Learning Centres and longer, more intensive programmes are available at the National Science Learning Centre in York. There are a growing number…

  11. The ideal physician entrepreneur.

    PubMed

    Bottles, K

    2000-01-01

    How does the sometimes elusive and high-stakes world of venture capital really work? How can physician executives with innovative ideas or new technologies approach venture capitalists to help them raise capital to form a start-up company? These important questions are explored in this new column on the physician as entrepreneur. The ideal physician executive is described as: (1) an expert in an area that Wall Street perceives as hot; (2) a public speaker who can enthusiastically communicate scientific and business plans to a variety of audiences; (3) a team leader who is willing to share equity in the company with other employees; (4) a recruiter and a motivator; (5) an implementer who can achieve milestones quickly that allow the company to go public as soon as possible; and (6) a realist who does not resent the terms of the typical deal. The lucrative world of the venture capitalists is foreign territory for physician executives and requires a great idea, charisma, risk-taking, connections, patience, and perseverance to navigate it successfully.

  12. Space Sciences and Idealism

    NASA Astrophysics Data System (ADS)

    Popov, M.

    Erwin Schrodinger suggested that " Scientific knowledge forms part of the idealistic background of human life", which exalted man from a nude and savage state to true humanity [Science and Humanism, Cambridge, 1961, p9]. Modern space sciences an space exploration are a brilliant demonstration of the validity of Schrodinger's thesis on Idealism. Moreover, Schrodingers thesis could be considered also as a basic principle for the New Educational Space Philosophical Project "TIMAEUS"."TIMAEUS" is not only an attempt to to start a new dialogue between Science, the Humanities and Religion; but also it is an origin of the cultural innovations of our so strange of globilisation. TIMAEUS, thus, can reveal Idealism as something more fundamental , more refined, more developed than is now accepted by the scientific community and the piblic. TIMAEUS has a significant cultural agenda, connected with the high orbital performance of the synthetic arts, combining a knowledge of the truly spiritual as well as the universal. In particular, classical ballet as a synthetic art can be a new and powerful perfector and re-creator of the real human, real idealistic, real complex culture in orbit. As is well known, Carlo Blasis, the most important dance theorist of the 19t h .century, made probably the first attempts to use the scientific ideas of Leonardo da Vinci and Isaac Newton for the understanding of the gravitational nature of balance and allegro in ballet. In particular Blasis's idea of the limited use of the legs in classical dance realised by the gifted pupils of Enrico Cecchetti - M.Fokine, A.Pavlova and V.Nijinsky, with thinkable purity and elegance of style. V.Nijinsky in his remarkable animation of the dance of two dimensional creatures of a Euclidean flat world (L'Apres Midi d'un Faune,1912) discovered that true classical dance has some gravitational limits. For example, Nijinsky's Faunes and Nymphs mut use running on the heels (In accordance with "Partitura" 1916); they

  13. The realities of idealism.

    PubMed

    Roslyn, J J

    1993-04-01

    I started out asking the question can we achieve our goals and are our goals realistic in the 1990s? I believe that we can achieve anything that we set our minds to. Our goals of providing quality care to our patients, performing research, teaching the next generation, and having an impact on our local environment are worth pursuing. However, the rules have changed and the status quo is simply not good enough. If we are to survive, we must be prepared for the future. You have the ability to change and the power to control the future. You are the future. Seize the opportunity and get involved. Become knowledgeable about health care economics, become involved with the political process, and position yourselves so that you can be a part of the solution to our health care system's woes. Don't allow the moment to pass. Don't be afraid of the realities of today, and don't forget your ideals and principles. Confront today's challenges with the same determination that academic surgeons through the years have confronted the unknown mysteries of disease. Let me conclude by trying to synthesize my remarks in five generic recommendations: 1. We need to go forward in the research area by developing multidisciplinary programs that involve basic science. These programs can be used to highlight our clinical areas and expertise. In this manner, both areas will be benefitted. 2. We need to educate the public and the government about the virtues of research and the importance of maintaining academic surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Thermal stability of idealized folded carbyne loops

    PubMed Central

    2013-01-01

    Self-unfolding items provide a practical convenience, wherein ring-like frames are contorted into a state of equilibrium and subsequently  pop up’ or deploy when perturbed from a folded structure. Can the same process be exploited at the molecular scale? At the limiting scale is a closed chain of single atoms, used here to investigate the limits of stability of such folded ring structures via full atomistic molecular dynamics. Carbyne is a one-dimensional carbon allotrope composed of sp-hybridized carbon atoms. Here, we explore the stability of idealized carbyne loops as a function of chain length, curvature, and temperature, and delineate an effective phase diagram between folded and unfolded states. We find that while overall curvature is reduced, in addition to torsional and self-adhesive energy barriers, a local increase in curvature results in the largest impedance to unfolding. PMID:24252156

  15. Researching Acquisition Sequences: Idealization and De-Idealization in SLA

    ERIC Educational Resources Information Center

    Ellis, Rod

    2015-01-01

    Idealization plays a fundamental role in scientific inquiry. This article examines the case for maintaining the claim that the second language acquisition (SLA) of grammatical structures such as negation manifests identifiable stages of acquisition. It proposes that, while research has demonstrated the need for de-idealization, there is no need to…

  16. Theory of Atomic Games

    NASA Astrophysics Data System (ADS)

    Zhang, Yikun

    2003-04-01

    A new atomic theory is proposed based on radiation mechanics. Atoms cannot be regarded as unrelated individuals, but in a game of claiming to emit photons. Every atom aims to minimize its expected energy by using mixed strategy in the game. Equilibrium points exist as the non-cooperative solution of an atomic game. In a gas composed of same atoms, every equilibrium point determines an optimum probability distribution of energy of each atom as well as of all atoms. The individual optimum is equivalent to the over-all optimum. In an ideal gas of identical atoms, the spin angular momentum of an electron in each atom can only take a series of discrete numerical values between the ground and excited states. There are two fundamental kinds of phase transitions, accomplished respectively by aggregation of atoms to form larger coalitions or by transformation of preexisting coalitions into new configurations. For the first kind, atomic games in both phases have the unique solution. The expected energies of two phases are equal at the critical point. For the second kind, atomic games have multiple solutions. There is often a fall of the expected energies between two phases at the critical point.

  17. Patient-centred care is a way of doing things: How healthcare employees conceptualize patient-centred care.

    PubMed

    Fix, Gemmae M; VanDeusen Lukas, Carol; Bolton, Rendelle E; Hill, Jennifer N; Mueller, Nora; LaVela, Sherri L; Bokhour, Barbara G

    2017-08-25

    Patient-centred care is now ubiquitous in health services research, and healthcare systems are moving ahead with patient-centred care implementation. Yet, little is known about how healthcare employees, charged with implementing patient-centred care, conceptualize what they are implementing. To examine how hospital employees conceptualize patient-centred care. We conducted qualitative interviews about patient-centred care during site four visits, from January to April 2013. We interviewed 107 employees, including leadership, middle managers, front line providers and staff at four US Veteran Health Administration (VHA) medical centres leading VHA's patient-centred care transformation. Data were analysed using grounded thematic analysis. Findings were then mapped to established patient-centred care constructs identified in the literature: taking a biopsychosocial perspective; viewing the patient-as-person; sharing power and responsibility; establishing a therapeutic alliance; and viewing the doctor-as-person. We identified three distinct conceptualizations: (i) those that were well aligned with established patient-centred care constructs surrounding the clinical encounter; (ii) others that extended conceptualizations of patient-centred care into the organizational culture, encompassing the entire patient-experience; and (iii) still others that were poorly aligned with patient-centred care constructs, reflecting more traditional patient care practices. Patient-centred care ideals have permeated into healthcare systems. Additionally, patient-centred care has been expanded to encompass a cultural shift in care delivery, beginning with patients' experiences entering a facility. However, some healthcare employees, namely leadership, see patient-centred care so broadly, it encompasses on-going hospital initiatives, while others consider patient-centred care as inherent to specific positions. These latter conceptualizations risk undermining patient-centred care

  18. Elastin: a representative ideal protein elastomer.

    PubMed Central

    Urry, D W; Hugel, T; Seitz, M; Gaub, H E; Sheiba, L; Dea, J; Xu, J; Parker, T

    2002-01-01

    During the last half century, identification of an ideal (predominantly entropic) protein elastomer was generally thought to require that the ideal protein elastomer be a random chain network. Here, we report two new sets of data and review previous data. The first set of new data utilizes atomic force microscopy to report single-chain force-extension curves for (GVGVP)(251) and (GVGIP)(260), and provides evidence for single-chain ideal elasticity. The second class of new data provides a direct contrast between low-frequency sound absorption (0.1-10 kHz) exhibited by random-chain network elastomers and by elastin protein-based polymers. Earlier composition, dielectric relaxation (1-1000 MHz), thermoelasticity, molecular mechanics and dynamics calculations and thermodynamic and statistical mechanical analyses are presented, that combine with the new data to contrast with random-chain network rubbers and to detail the presence of regular non-random structural elements of the elastin-based systems that lose entropic elastomeric force upon thermal denaturation. The data and analyses affirm an earlier contrary argument that components of elastin, the elastic protein of the mammalian elastic fibre, and purified elastin fibre itself contain dynamic, non-random, regularly repeating structures that exhibit dominantly entropic elasticity by means of a damping of internal chain dynamics on extension. PMID:11911774

  19. Dimensional Analysis Using Toric Ideals: Primitive Invariants

    PubMed Central

    Atherton, Mark A.; Bates, Ronald A.; Wynn, Henry P.

    2014-01-01

    Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer matrix from the initial integer matrix holding the exponents for the derived quantities. The matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by . One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of , is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found. PMID:25436774

  20. Be Ye Perfect? Religious Ideals in Education

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.

    2006-01-01

    This article explores the meaning of "religious ideals" and their possible role in education. "Religious ideals" are defined as ideals that acquire meaning due to a belief in transcendence or a divine being. Two kinds of religious ideals are being distinguished, namely ideals that are constituted by a belief in a transcendent being and ideals that…

  1. On fuzzy ideals of BL-algebras.

    PubMed

    Meng, Biao Long; Xin, Xiao Long

    2014-01-01

    In this paper we investigate further properties of fuzzy ideals of a BL-algebra. The notions of fuzzy prime ideals, fuzzy irreducible ideals, and fuzzy Gödel ideals of a BL-algebra are introduced and their several properties are investigated. We give a procedure to generate a fuzzy ideal by a fuzzy set. We prove that every fuzzy irreducible ideal is a fuzzy prime ideal but a fuzzy prime ideal may not be a fuzzy irreducible ideal and prove that a fuzzy prime ideal ω is a fuzzy irreducible ideal if and only if ω(0) = 1 and |Im(ω)| = 2. We give the Krull-Stone representation theorem of fuzzy ideals in BL-algebras. Furthermore, we prove that the lattice of all fuzzy ideals of a BL-algebra is a complete distributive lattice. Finally, it is proved that every fuzzy Boolean ideal is a fuzzy Gödel ideal, but the converse implication is not true.

  2. Non-Euclidean Ideal Spectrometry

    NASA Astrophysics Data System (ADS)

    Sá Earp, Henrique N.; Sicca, Vladmir; Kyotoku, Bernardo B. C.

    2016-12-01

    We describe the mathematical scheme for an anomaly-free ideal spectrometer, based on a 2-dimensional plane medium with conical regions of bounded slope. Moreover, the construction may be realised in many different configurations.

  3. Spaces of Ideal Convergent Sequences

    PubMed Central

    Mursaleen, M.; Sharma, Sunil K.

    2014-01-01

    In the present paper, we introduce some sequence spaces using ideal convergence and Musielak-Orlicz function ℳ = (Mk). We also examine some topological properties of the resulting sequence spaces. PMID:24592143

  4. Preoccupied with the Self: Towards Self-Responsible, Enterprising, Flexible and Self-Centred Subjectivity in Education

    ERIC Educational Resources Information Center

    Brunila, Kristiina; Siivonen, Päivi

    2016-01-01

    In the neoliberal order, the ideal self is self-responsible, enterprising, flexible and self-centred. Regarding this ideal we argue that the rise of therapisation in society, and in education, particularly, links both the therapeutic and enterprising discourses. The article examines how these discourses jointly produce and legitimate the ideal,…

  5. Preoccupied with the Self: Towards Self-Responsible, Enterprising, Flexible and Self-Centred Subjectivity in Education

    ERIC Educational Resources Information Center

    Brunila, Kristiina; Siivonen, Päivi

    2016-01-01

    In the neoliberal order, the ideal self is self-responsible, enterprising, flexible and self-centred. Regarding this ideal we argue that the rise of therapisation in society, and in education, particularly, links both the therapeutic and enterprising discourses. The article examines how these discourses jointly produce and legitimate the ideal,…

  6. Dimensional analysis using toric ideals: primitive invariants.

    PubMed

    Atherton, Mark A; Bates, Ronald A; Wynn, Henry P

    2014-01-01

    Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units [Formula: see text] etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer [Formula: see text] matrix from the initial integer [Formula: see text] matrix holding the exponents for the derived quantities. The [Formula: see text] matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by [Formula: see text]. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of [Formula: see text], is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.

  7. An ideal free-kick

    NASA Astrophysics Data System (ADS)

    De Luca, R.; Faella, O.

    2017-01-01

    The kinematics of a free-kick is studied. As in projectile motion, the free-kick is ideal since we assume that a point-like ball moves in the absence of air resistance. We have experienced the fortunate conjuncture of a classical mechanics lecture taught right before an important football game. These types of sports events might trigger a great deal of attention from the classroom. The idealized problem is devised in such a way that students are eager to come to the end of the whole story.

  8. Idealism and materialism in perception.

    PubMed

    Rose, David; Brown, Dora

    2015-01-01

    Koenderink (2014, Perception, 43, 1-6) has said most Perception readers are deluded, because they believe an 'All Seeing Eye' observes an objective reality. We trace the source of Koenderink's assertion to his metaphysical idealism, and point to two major weaknesses in his position-namely, its dualism and foundationalism. We counter with arguments from modern philosophy of science for the existence of an objective material reality, contrast Koenderink's enactivism to his idealism, and point to ways in which phenomenology and cognitive science are complementary and not mutually exclusive.

  9. (Fuzzy) Ideals of BN-Algebras.

    PubMed

    Dymek, Grzegorz; Walendziak, Andrzej

    2015-01-01

    The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained.

  10. Exotic Phases of Ultracold Atoms

    DTIC Science & Technology

    2011-11-18

    lattices". 5 10 July 2007 Henri Poincare Institute, Paris, France, Quantum Gases Program Seminar: “Some unconventional phases of cold atomic matter with or...Pittsburgh, PA. (Attended) 10. PI, Paris Program on “Quantum Gases”, Centre Emile Borel, Institut Henri Poincaré, April 23- July 20, 2007, Paris...Pittsburgh. Promoted to the rank of Associated Profes- sor, effective Sep 1, 2009. 7. Visiting Scientist, Centre Emile Borel, Institut Henri Poincaré

  11. Characteristics of an Ideal Colleague.

    ERIC Educational Resources Information Center

    Nielsen, Linda

    1979-01-01

    A stratified random sample of male and female faculty members from two universities was surveyed regarding traits of the ideal colleague. The results were analyzed according to the respondent's sex, tenure status, private or state university position, and academic discipline. Also diagnosed was the masculine or feminine value of each trait. (JMD)

  12. Chemical Laws, Idealization and Approximation

    ERIC Educational Resources Information Center

    Tobin, Emma

    2013-01-01

    This paper examines the notion of laws in chemistry. Vihalemm ("Found Chem" 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all "ceteris paribus" laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are…

  13. Chemical Laws, Idealization and Approximation

    ERIC Educational Resources Information Center

    Tobin, Emma

    2013-01-01

    This paper examines the notion of laws in chemistry. Vihalemm ("Found Chem" 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all "ceteris paribus" laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are…

  14. Temperature and the Ideal Gas

    ERIC Educational Resources Information Center

    Daisley, R. E.

    1973-01-01

    Presents some organized ideas in thermodynamics which are suitable for use with high school (GCE A level or ONC) students. Emphases are placed upon macroscopic observations and intimate connection of the modern definition of temperature with the concept of ideal gas. (CC)

  15. Temperature and the Ideal Gas

    ERIC Educational Resources Information Center

    Daisley, R. E.

    1973-01-01

    Presents some organized ideas in thermodynamics which are suitable for use with high school (GCE A level or ONC) students. Emphases are placed upon macroscopic observations and intimate connection of the modern definition of temperature with the concept of ideal gas. (CC)

  16. [Harmony--idea and ideal].

    PubMed

    Scharfetter, C

    1996-03-01

    The concept of the whole as an ideal of gestalt and value is sketched. In the concrete situation of healer and patient a multiperspective approach rather than a realization of wholeness has to be enough, taking into account somatic, physiological, intraindividual-psychological, interpersonal-social and transpersonal aspects of personalities in diagnosis and treatment.

  17. An orthotropic source of thermal atoms

    SciTech Connect

    Dinneen, T.; Ghiorso, A.; Gould, H.

    1995-07-01

    A source of thermal atoms that emits 100% of its atoms into a narrow beam with small angular divergence is described. It uses both surface ionization and surface neutralization in conjunction with electric fields to selectively emit a highly directional (orthotropic) beam of neutral atoms. The ion recycling process can be modulated electronically and lends itself to scanning. This orthotropic source is ideal for the efficient use of rare atomic species, well suited for atomic clocks, essential in the efficient delivery of radioactive atoms to optical traps, and has potential to produce ultra high intensity beams of stable atoms.

  18. Lidar Calibration Centre

    NASA Astrophysics Data System (ADS)

    Pappalardo, Gelsomina; Freudenthaler, Volker; Nicolae, Doina; Mona, Lucia; Belegante, Livio; D'Amico, Giuseppe

    2016-06-01

    This paper presents the newly established Lidar Calibration Centre, a distributed infrastructure in Europe, whose goal is to offer services for complete characterization and calibration of lidars and ceilometers. Mobile reference lidars, laboratories for testing and characterization of optics and electronics, facilities for inspection and debugging of instruments, as well as for training in good practices are open to users from the scientific community, operational services and private sector. The Lidar Calibration Centre offers support for trans-national access through the EC HORIZON2020 project ACTRIS-2.

  19. Measurement of optical Feshbach resonances in an ideal gas.

    PubMed

    Blatt, S; Nicholson, T L; Bloom, B J; Williams, J R; Thomsen, J W; Julienne, P S; Ye, J

    2011-08-12

    Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the optical Feshbach resonance effect in an ultracold gas of bosonic (88)Sr. A systematic measurement of three resonances allows precise determinations of the optical Feshbach resonance strength and scaling law, in agreement with coupled-channel theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. Optical Feshbach resonance could be used to control atomic interactions with high spatial and temporal resolution.

  20. Single atom electrochemical and atomic analytics

    NASA Astrophysics Data System (ADS)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  1. Determination of performance of non-ideal aluminized explosives.

    PubMed

    Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Poor, Karim Esmail; Shokrollahi, Arash; Zali, Abbas; Yousefi, Mohammad Hassan

    2006-09-01

    Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

  2. Maple Leaf Outdoor Centre.

    ERIC Educational Resources Information Center

    Maguire, Molly; Gunton, Ric

    2000-01-01

    Maple Leaf Outdoor Centre (Ontario) has added year-round outdoor education facilities and programs to help support its summer camp for disadvantaged children. Schools, youth centers, religious groups, and athletic teams conduct their own programs, collaborate with staff, or use staff-developed programs emphasizing adventure education and personal…

  3. Implementing Responsibility Centre Budgeting

    ERIC Educational Resources Information Center

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  4. The Iranian Documentation Centre.

    ERIC Educational Resources Information Center

    Harvey, John F.

    The purpose of the Iranian Documentation Centr (Irandoc) was to collect that portion of the world's literature which was pertinent to Iran's research interests, to organize that material, and to promote its use by Iranian researchers. Stated more succinctly, Irandoc's purpose was to obtain ready access to the world's scientific literature in order…

  5. Winnipeg Centre Project.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg.

    The Winnipeg Centre Project is a field-based, work-study program that attempts to create more appropriate education for the inner-city child. Sponsored by the Planning and Research Branch of the Department of Colleges and Universities Affairs and administered by Brandon University in consultation with the Winnipeg School Division, the project is…

  6. Discovering a Discovery Centre

    ERIC Educational Resources Information Center

    McCullagh, John; Stewart, James; Greenwood, Julian

    2007-01-01

    There has recently been a growth in the popularity of "science centres" and this development provides an excellent opportunity to support the primary science curriculum. Their use is therefore well worth including within initial teacher education courses. Hence, undergraduate student teachers at Stranmillis University College Belfast may…

  7. Discovering a Discovery Centre

    ERIC Educational Resources Information Center

    McCullagh, John; Stewart, James; Greenwood, Julian

    2007-01-01

    There has recently been a growth in the popularity of "science centres" and this development provides an excellent opportunity to support the primary science curriculum. Their use is therefore well worth including within initial teacher education courses. Hence, undergraduate student teachers at Stranmillis University College Belfast may…

  8. Implementing Responsibility Centre Budgeting

    ERIC Educational Resources Information Center

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  9. Wycheproof Education Centre.

    ERIC Educational Resources Information Center

    Sweetnam and Godfrey, Melbourne (Australia).

    The Wycheproof township in New South Wales (Australia) is the regional center for a grain farming community. The Wycheproof Education Centre was formed by the merger of a separate primary and secondary school (on one site with existing buildings), into a single governing body that is educationally structured into junior, middle, and senior…

  10. Wycheproof Education Centre.

    ERIC Educational Resources Information Center

    Sweetnam and Godfrey, Melbourne (Australia).

    The Wycheproof township in New South Wales (Australia) is the regional center for a grain farming community. The Wycheproof Education Centre was formed by the merger of a separate primary and secondary school (on one site with existing buildings), into a single governing body that is educationally structured into junior, middle, and senior…

  11. Representation of Ideal Magnetohydrodynamic Modes

    SciTech Connect

    Roscoe B. White

    2013-01-15

    One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through δ Β = ∇ X (xi X B) ensures that δ B • ∇ ψ = 0 at a resonance, with ψ labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation δ Β = ∇ X αB. These two representations are equivalent, but the vanishing of δ B • ∇ψ at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in xi to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed

  12. The fate of idealism in modern medicine.

    PubMed

    Manson, Aaron

    1994-01-01

    William Osler's description of the ideal physician remains the dominant character-ideal for modern physicians. He believed that the personality traits that resulted from a belief in ascetic Protestantism, what has been called the Puritan temper, were essential in the practice of medicine. However, this idealism has been weakened by modern psychological theories which view idealism as an illness. In a culture oriented to health, rather than virtue, as an ultimate ideal, physicians can help develop a science of limits.

  13. [The "ideal" doctor from the view of psychiatric patients].

    PubMed

    Theisel, Susanne; Schielein, Tanja; Spiessl, Hermann

    2010-09-01

    The study aimed to investigate the expectations of patients in a general psychiatric hospital regarding an "ideal" doctor. 60 problem centred interviews with psychiatric in-patients were analysed by using a summarizing content analysis. Analysis of interview data showed three fundamental areas, which are important for patients: doctors' personality, physician-patient-interaction and treatment as well as doctors' treatment environment. The "ideal" doctor 1. is reachable and takes his time (75%), 2. is friendly and congenial (63%), 3. shows commitment and interest (60%), 4. is an understanding and sensitive contact person (60%), 5. is responsive to needs of patients (55%). For that reason, optimal time management and social competence is necessary and should be a part of medical students' and doctors' education. Focusing on patients' expectations can positively influence their treatment satisfaction.

  14. On Fuzzy Ideals of BL-Algebras

    PubMed Central

    Xin, Xiao Long

    2014-01-01

    In this paper we investigate further properties of fuzzy ideals of a BL-algebra. The notions of fuzzy prime ideals, fuzzy irreducible ideals, and fuzzy Gödel ideals of a BL-algebra are introduced and their several properties are investigated. We give a procedure to generate a fuzzy ideal by a fuzzy set. We prove that every fuzzy irreducible ideal is a fuzzy prime ideal but a fuzzy prime ideal may not be a fuzzy irreducible ideal and prove that a fuzzy prime ideal ω is a fuzzy irreducible ideal if and only if ω(0) = 1 and |Im⁡(ω)| = 2. We give the Krull-Stone representation theorem of fuzzy ideals in BL-algebras. Furthermore, we prove that the lattice of all fuzzy ideals of a BL-algebra is a complete distributive lattice. Finally, it is proved that every fuzzy Boolean ideal is a fuzzy Gödel ideal, but the converse implication is not true. PMID:24892085

  15. SPOT4 Management Centre

    NASA Technical Reports Server (NTRS)

    Labrune, Yves; Labbe, X.; Roussel, A.; Vielcanet, P.

    1994-01-01

    In the context of the CNES SPOT4 program CISI is particularly responsible for the development of the SPOT4 Management Centre, part of the SPOT4 ground control system located at CNES Toulouse (France) designed to provide simultaneous control over two satellites. The main operational activities are timed to synchronize with satellite visibilities (ten usable passes per day). The automatic capability of this system is achieved through agenda services (sequence of operations as defined and planned by operator). Therefore, the SPOT4 Management Centre offers limited, efficient and secure human interventions for supervision and decision making. This paper emphasizes the main system characteristics as degree of automation, level of dependability and system parameterization.

  16. Elderly Care Centre

    NASA Astrophysics Data System (ADS)

    Wagiman, Aliani; Haja Bava Mohidin, Hazrina; Ismail, Alice Sabrina

    2016-02-01

    The demand for elderly centre has increased tremendously abreast with the world demographic change as the number of senior citizens rose in the 21st century. This has become one of the most crucial problems of today's era. As the world progress into modernity, more and more people are occupied with daily work causing the senior citizens to lose the care that they actually need. This paper seeks to elucidate the best possible design of an elderly care centre with new approach in order to provide the best service for them by analysing their needs and suitable activities that could elevate their quality of life. All these findings will then be incorporated into design solutions so as to enhance the living environment for the elderly especially in Malaysian context.

  17. International Seismological Centre

    USGS Publications Warehouse

    Spall, H.; Hughes, A.

    1979-01-01

    The International Seismological Centre had its origins when the British seismologist Professor John Milne returned to England from Japan in 1895 to retire at Shide on the Isle of Eight. In cooperation with the British Association for the Advancement of Science, Milne had set up a number of seismographic stations around the world and, while Tokyo, had published a Catalogue of 8,33 Earthquakes Recorded in Japan, 1885-1892. 

  18. Sedeonic equations of ideal fluid

    NASA Astrophysics Data System (ADS)

    Mironov, Victor L.; Mironov, Sergey V.

    2017-08-01

    In the present paper, we propose the generalized equations for an ideal fluid based on space-time algebra of sixteen-component sedeons. It is shown that the dynamics of isentropic fluid can be described by sedeonic first-order wave equation for fluid potentials. The key features of the proposed formalism are illustrated on the problem of the sound waves propagation. We consider the plane wave solution of linearized sedeonic wave equation and derive the second-order relations for the sound potential analogues to the Poynting theorem in electrodynamics. The generalization of proposed sedeonic equations for the description of viscous fluid is also discussed.

  19. Can Chemistry Teachers' Centres Survive?

    ERIC Educational Resources Information Center

    Garforth, F. M.

    1972-01-01

    The difficulties faced by the Hull Chemistry Teachers' Centre in England are discussed. The lack of finances and time, as well as organizational difficulties in relationship with Science Centres and universities are among the problems. (TS)

  20. Measuring explosive non-ideality

    SciTech Connect

    Souers, P C

    1999-02-17

    The sonic reaction zone length may be measured by four methods: (1) size effect, (2) detonation front curvature, (3) crystal interface velocity and (4) in-situ gauges. The amount of data decreases exponentially from (1) to (4) with there being almost no gauge data for prompt detonation at steady state. The ease and clarity of obtaining the reaction zone length increases from (1) to (4). The method of getting the reaction zone length, , is described for the four methods. A measure of non-ideality is proposed: the reaction zone length divided by the cylinder radius. N = /R{sub o}. N = 0 for true ideality. It also decreases with increasing radius as it should. For N < 0.10, an equilibrium EOS like the JWL may be used. For N > 0.10, a time-dependent description is essential. The crystal experiment, which measures the particle velocity of an explosive-transparent material interface, is presently rising in importance. We examine the data from three experiments and apply: (1) an impedance correction that transfers the explosive C-J particle velocity to the corresponding value for the interface, and (2) multiplies the interface time by 3/4 to simulate the explosive speed of sound. The result is a reaction zone length comparable to those obtained by other means. A few explosives have reaction zones so small that the change of slope in the particle velocity is easily seen.

  1. Imagining the ideal dairy farm.

    PubMed

    Cardoso, Clarissa S; Hötzel, Maria José; Weary, Daniel M; Robbins, Jesse A; von Keyserlingk, Marina A G

    2016-02-01

    Practices in agriculture can have negative effects on the environment, rural communities, food safety, and animal welfare. Although disagreements are possible about specific issues and potential solutions, it is widely recognized that public input is needed in the development of socially sustainable agriculture systems. The aim of this study was to assess the views of people not affiliated with the dairy industry on what they perceived to be the ideal dairy farm and their associated reasons. Through an online survey, participants were invited to respond to the following open-ended question: "What do you consider to be an ideal dairy farm and why are these characteristics important to you?" Although participants referenced social, economic, and ecological aspects of dairy farming, animal welfare was the primary issue raised. Concern was expressed directly about the quality of life for the animals, and the indirect effect of animal welfare on milk quality. Thus participants appeared to hold an ethic for dairy farming that included concern for the animal, as well as economic, social, and environmental aspects of the dairy system.

  2. Representation of ideal magnetohydrodynamic modes

    SciTech Connect

    White, R. B.

    2013-02-15

    One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B(vector sign)={nabla} Multiplication-Sign ({xi}(vector sign) Multiplication-Sign B(vector sign)) ensures that {delta}B(vector sign){center_dot}{nabla}{psi}=0 at a resonance, with {psi} labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation {delta}B(vector sign)={nabla} Multiplication-Sign {alpha}B(vector sign). These two representations are equivalent, but the vanishing of {delta}B(vector sign){center_dot}{nabla}{psi} at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in {xi}(vector sign) to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed.

  3. On central ideals of finitely generated binary (-1,1)-algebras

    SciTech Connect

    Pchelintsev, S V

    2002-04-30

    In 1975 the author proved that the centre of a free finitely generated (-1,1)-algebra contains a non-zero ideal of the whole algebra. Filippov proved that in a free alternative algebra of rank {>=}4 there exists a trivial ideal contained in the associative centre. Il'tyakov established that the associative nucleus of a free alternative algebra of rank 3 coincides with the ideal of identities of the Cayley-Dickson algebra. In the present paper the above-mentioned theorem of the author is extended to free finitely generated binary (-1,1)-algebras. Theorem. The centre of a free finitely generated binary (-1,1)-algebra of rank {>=}3 over a field of characteristic distinct from 2 and 3 contains a non-zero ideal of the whole algebra. As a by-product, we shall prove that the T-ideal generated by the function (z,x,(x,x,y)) in a free binary (-1,1)-algebra of finite rank is soluble. We deduce from this that the basis rank of the variety of binary (-1,1)-algebras is infinite.

  4. (Fuzzy) Ideals of BN-Algebras

    PubMed Central

    Walendziak, Andrzej

    2015-01-01

    The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained. PMID:26125050

  5. Computational Methods for Ideal Magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Kercher, Andrew D.

    Numerical schemes for the ideal magnetohydrodynamics (MHD) are widely used for modeling space weather and astrophysical flows. They are designed to resolve the different waves that propagate through a magnetohydro fluid, namely, the fast, Alfven, slow, and entropy waves. Numerical schemes for ideal magnetohydrodynamics that are based on the standard finite volume (FV) discretization exhibit pseudo-convergence in which non-regular waves no longer exist only after heavy grid refinement. A method is described for obtaining solutions for coplanar and near coplanar cases that consist of only regular waves, independent of grid refinement. The method, referred to as Compound Wave Modification (CWM), involves removing the flux associated with non-regular structures and can be used for simulations in two- and three-dimensions because it does not require explicitly tracking an Alfven wave. For a near coplanar case, and for grids with 213 points or less, we find root-mean-square-errors (RMSEs) that are as much as 6 times smaller. For the coplanar case, in which non-regular structures will exist at all levels of grid refinement for standard FV schemes, the RMSE is as much as 25 times smaller. A multidimensional ideal MHD code has been implemented for simulations on graphics processing units (GPUs). Performance measurements were conducted for both the NVIDIA GeForce GTX Titan and Intel Xeon E5645 processor. The GPU is shown to perform one to two orders of magnitude greater than the CPU when using a single core, and two to three times greater than when run in parallel with OpenMP. Performance comparisons are made for two methods of storing data on the GPU. The first approach stores data as an Array of Structures (AoS), e.g., a point coordinate array of size 3 x n is iterated over. The second approach stores data as a Structure of Arrays (SoA), e.g. three separate arrays of size n are iterated over simultaneously. For an AoS, coalescing does not occur, reducing memory efficiency

  6. Ideal Clutters That Do Not Pack

    DTIC Science & Technology

    2016-09-18

    Ideal clutters that do not pack Ahmad Abdi Gérard Cornuéjols Kanstantsin Pashkovich September 18, 2016 Abstract For a clutter C over ground set E...impelled by the lack of a qualitative characterization for ideal minimally non-packing (mnp) clutters, we reduce ideal mnp clutters even further by taking...their identifications. In doing so, we reveal chains of ideal mnp clutters, demonstrate the centrality of mnp clutters with covering number two, as

  7. Recharging Our Sense of Idealism: Concluding Thoughts

    ERIC Educational Resources Information Center

    D'Andrea, Michael; Dollarhide, Colette T.

    2011-01-01

    In this article, the authors aim to recharge one's sense of idealism. They argue that idealism is the Vitamin C that sustains one's commitment to implementing humanistic principles and social justice practices in the work of counselors and educators. The idealism that characterizes counselors and educators who are humanistic and social justice…

  8. Recharging Our Sense of Idealism: Concluding Thoughts

    ERIC Educational Resources Information Center

    D'Andrea, Michael; Dollarhide, Colette T.

    2011-01-01

    In this article, the authors aim to recharge one's sense of idealism. They argue that idealism is the Vitamin C that sustains one's commitment to implementing humanistic principles and social justice practices in the work of counselors and educators. The idealism that characterizes counselors and educators who are humanistic and social justice…

  9. [The ideal body: media pedagogy].

    PubMed

    Ribeiro, Rubia Guimarães; da Silva, Karen Schein; Kruse, Maria Henriqueta Luce

    2009-03-01

    We present enunciations that circulate in the media regarding the body, discussing the ways in which the speeches related with the maintenance of health and aesthetics invest in its improvement. Therefore, we used the Caderno Vida, a weekly insert of Zero Hora, for we understand it as owner of a proper speech that has the power of subjectivate people The analysis is part of Cultural Studies and it is based on the ideas of Michel Foucault. The methodological strategy used was the speech analysis of subjects about body care. The periodical questions its readers using speeches that point to beauty health and success The constructed categories were: how is the ideal body, what to do to have such body and why we must have this body Balanced feeding, practice of regular physical activities and the accomplishment of plastic surgeries are recommendations recurrently found in weekly inserts.

  10. Ideal-viscoplastic extrusion model

    NASA Astrophysics Data System (ADS)

    Groth, C. P. T.; Gottlieb, J. J.

    An approximate one-dimensional analysis is presented for the extrusion of incompressible ideal-viscoplastic material through converging axisymmetric dies. The extrusion model incorporates the fundamental effects of inertia, plastic deformation, strain-rate behavior, and surface friction by employing the constitutive relations for a Bingham-type body to describe the stress-strain-rate behavior of the extrudite, an appropriate quasi-steady localy-spherical kinematically-admissible velocity field to represent the actual flowfield, and a combination Coulomb and constant-shear-factor laws to estimate the frictional forces along the die surface. Comparisons of the predictions of the theory to experimental data and finite-element computations demonstrate that it is a useful and economical tool for predicting many extrusion processes.

  11. Steady non-ideal detonations

    NASA Astrophysics Data System (ADS)

    Sharpe, Gary

    2009-06-01

    Theories for determining the velocity of detonation (VoD) in highly non-ideal explosives, e.g. commercial explosives used in mining, are discussed. Such explosives have critical charge diameters of several centimetres. An analysis of the interaction between detonations and confining materials along the explosive-confiner interface reveals there a two main types of interaction. In the first (denoted here by case 1) the detonation drives an oblique shock into the confiner. For the second (case 2), a wave propagates in the confiner ahead of the detonation in the explosive. Shock polar interactions are examined for commercial explosives and rocks, which shows that a significant proportion of problems are case 2 in mining. For case 1, numerical simulations show that for a given explosive model there is a unique relationship (valid for all charge diameters and confinements) between the VoD and the curvature of the detonation shock at the charge axis. This relationship is shown to be well predicted by a quasi-one-dimensional type analysis. A simple detonation shock dynamics method which uses this relationships predicts well the VoD even in highly non-ideal cases, provided the explosive is sufficiently confined (usually the case in mining), but which is inaccurate in the limit of an unconfined charge. Preliminary results of a novel variational method for solving the unconfined situation are also discussed. Numerical simulations are performed to investigate the coupling mechanisms in case 2 situations, including the influence on diameter effects. It is shown that, in agreement with an approximate theory, the detonation is driven up to VoDs above the confiner's sound speed, and the wave in the confiner weakly pre-compresses the explosive ahead of the detonation front.

  12. Comparison of real and idealized cetacean flippers

    NASA Astrophysics Data System (ADS)

    Murray, Mark; Weber, Paul; Howle, Laurens; Fish, Frank

    2009-11-01

    We explored the consequences of the idealization process by creating exact scale models of cetacean flippers using CT scans, creating corresponding idealized versions, then determining the hydrodynamic characteristics of the models via water tunnel testing. We found that the majority of the idealized models did not exhibit fluid dynamic properties that were drastically different from those of the real models, although multiple consequences resulting from the idealization process were evident. Drag performance was significantly improved by idealization. Overall, idealization is an excellent way to capture the relevant effects of a phenomena found in nature, which spares the researcher from having to painstakingly create exact models, although we have found that there are situations where idealization may have unintended consequences such as one model that exhibited a decrease in lift performance.

  13. Ultracold strongly coupled gas: A near-ideal liquid

    NASA Astrophysics Data System (ADS)

    Gelman, Boris A.; Shuryak, Edward V.; Zahed, Ismail

    2005-10-01

    Feshbach resonances of trapped ultracold alkali-metal atoms allow to vary the atomic scattering length a . At very large values of a the system enters an universal strongly coupled regime in which its properties—the ground-state energy, pressure, etc.—become independent of a . We discuss the transport properties of such systems. In particular, the universality arguments imply that the shear viscosity of ultracold Fermi atoms at the Feschbach resonance is proportional to the particle number density n and the Plank constant ℏ : η=ℏnαη , where αη is a universal constant. Using Heisenberg uncertainty principle and Einstein’s relation between diffusion and viscosity we argue that the viscosity has the lower bound given by αη⩽(6π)-1 . We relate the damping of low-frequency density oscillations of ultracold optically trapped Li6 atoms to viscosity and find that the value of the coefficient αη is about 0.3. We also show that such a small viscosity cannot be explained by kinetic theory based on binary scattering. We conclude that the system of ultracold atoms near the Feshbach resonance is a near-ideal liquid.

  14. Ultracold strongly coupled gas: A near-ideal liquid

    SciTech Connect

    Gelman, Boris A.; Shuryak, Edward V.; Zahed, Ismail

    2005-10-15

    Feshbach resonances of trapped ultracold alkali-metal atoms allow to vary the atomic scattering length a. At very large values of a the system enters an universal strongly coupled regime in which its properties--the ground-state energy, pressure, etc.--become independent of a. We discuss the transport properties of such systems. In particular, the universality arguments imply that the shear viscosity of ultracold Fermi atoms at the Feschbach resonance is proportional to the particle number density n and the Plank constant ({Dirac_h}/2{pi}): {eta}=({Dirac_h}/2{pi})n{alpha}{sub {eta}}, where {alpha}{sub {eta}} is a universal constant. Using Heisenberg uncertainty principle and Einstein's relation between diffusion and viscosity we argue that the viscosity has the lower bound given by {alpha}{sub {eta}}{<=}(6{pi}){sup -1}. We relate the damping of low-frequency density oscillations of ultracold optically trapped {sup 6}Li atoms to viscosity and find that the value of the coefficient {alpha}{sub {eta}} is about 0.3. We also show that such a small viscosity cannot be explained by kinetic theory based on binary scattering. We conclude that the system of ultracold atoms near the Feshbach resonance is a near-ideal liquid.

  15. The pontine micturition centres.

    PubMed

    Griffiths, Derek J

    2002-01-01

    To review recent literature on the function of the two postulated pontine regions (the M- and L-regions) concerned with lower urinary tract control. The work reviewed is based on stimulation and lesion experiments and post-operative follow-up in the cat, supported by acute chemical stimulation and blocking experiments in the rat and PET functional brain scanning in humans. The M-region in the cat, homologous to Barrington's micturition centre and to a similar area in humans, is a small region both specific and necessary to voiding, the origin of the final common pathway to bladder and urethra, and the locus of co-ordination of the bladder and the striated sphincter. The L-region in the cat is part of a larger, less specific area that probably serves sphincter control in various circumstances, not exclusively micturition. The homolog of this region in the human or in the rat has not been adequately established.

  16. [The primary healthcare centres].

    PubMed

    Brambilla, Antonio; Maciocco, Gavino

    2014-04-01

    The central attributes of primary care are: first contact (accessibility), longitudinality (person- focused preventive and curative care overtime), patient-oriented comprehensiveness and coordination (including navigation towards secondary and tertiary care). Besides taking care of the needs of the individuals, primary health care teams are also looking at the community, especially when addressing social determinants of health. The rationale for the benefits for primary care for health has been found in: 1) greater access to needed services; 2) better quality of care; 3) a greater focus on prevention; 4) early management of health problems; 5) organizing and delivering high quality care for chronic non-communicable diseases. This paper describes the role of primary healthcare centres in strengthening community primary services and in reducing health inequalities. Furthemore, the experiences of Regional Health Services from Tuscany and Emilia-Romagna are discussed, with a brief overview of the literature.

  17. What is the ideal crystalloid?

    PubMed

    Raghunathan, Karthik; Nailer, Patrick; Konoske, Ryan

    2015-08-01

    We discuss the importance of the composition of intravenous crystalloid solutions. On the basis of current physiologic principles, evidence from basic science and clinical experiments, recent observational studies, and clinical trials, we conclude that the 'ideal crystalloid' depends on clinical context. We make recommendations on solutions that may be used during critical illness, major surgery, and certain clinical situations. The routine use of solutions with a supraphysiologic chloride content and a low strong ion difference (SID), such as isotonic saline solution, may be associated with adverse outcomes, especially among critically ill patients. On the contrary, solutions with a physiologic chloride content and a 'balanced' electrolyte composition (SID closer to plasma) may improve the likelihood of survival. The distribution of different types of crystalloids across traditional 'body compartments' is a function of osmolality of the fluid infused relative to plasma, integrity of the glycocalyx, and the hemodynamic/'volume' state of the patient. During critical illness, the routine administration of colloids may offer no clinical benefits compared with the use of crystalloids. Crystalloids, like other types of intravenous fluids, are drugs with important effects on clinical outcomes that may be mediated by osmolality, chloride content, and SID.

  18. Ideal statistically quasi Cauchy sequences

    NASA Astrophysics Data System (ADS)

    Savas, Ekrem; Cakalli, Huseyin

    2016-08-01

    An ideal I is a family of subsets of N, the set of positive integers which is closed under taking finite unions and subsets of its elements. A sequence (xk) of real numbers is said to be S(I)-statistically convergent to a real number L, if for each ɛ > 0 and for each δ > 0 the set { n ∈N :1/n | { k ≤n :| xk-L | ≥ɛ } | ≥δ } belongs to I. We introduce S(I)-statistically ward compactness of a subset of R, the set of real numbers, and S(I)-statistically ward continuity of a real function in the senses that a subset E of R is S(I)-statistically ward compact if any sequence of points in E has an S(I)-statistically quasi-Cauchy subsequence, and a real function is S(I)-statistically ward continuous if it preserves S(I)-statistically quasi-Cauchy sequences where a sequence (xk) is called to be S(I)-statistically quasi-Cauchy when (Δxk) is S(I)-statistically convergent to 0. We obtain results related to S(I)-statistically ward continuity, S(I)-statistically ward compactness, Nθ-ward continuity, and slowly oscillating continuity.

  19. Steady Non-Ideal Detonation

    NASA Astrophysics Data System (ADS)

    Sharpe, G. J.; Luheshi, M. Y.; Braithwaite, M.; Falle, S. A. E. G.

    2009-12-01

    Highly non-ideal explosives, such as commercial ammonium nitrate based explosives used in mining and blasting, have critical charge diameters of several centimetres and relatively low detonation speeds. Shock polar match analyses between these explosives and confining inert materials give two main types of interactions. For the first type (denoted here by case I), the detonation drives an oblique shock into the confiner. For the second type (case II), a wave propagates in the confiner ahead of the detonation wave in the explosive. In case I, numerical simulations show that for a given explosive model there is a unique relationship (valid for all charge diameters and confinements) between the velocity of detonation (VoD) and the curvature of the detonation shock at the charge axis. This relationship is shown to be well predicted by a quasi-one-dimensional analysis. A simple detonation shock dynamics method which uses this relationship predicts the VoD provided the explosive is sufficiently confined (usually the case in mining), but is inaccurate in the limit of an unconfined charge. For commercial explosives confined by rocks, a significant proportion of problems are case II. Numerical simulations are performed to investigate the coupling mechanisms in these situations. It is found that, in agreement with an approximate theory, the detonation is driven up to VoDs near the confiner's sound speed, and the wave in the confiner weakly pre-compresses the explosive ahead of the detonation front.

  20. (Re)Visioning the Centre: Education Reform and the "Ideal" Citizen of the Future

    ERIC Educational Resources Information Center

    Graham, Linda J.

    2007-01-01

    Discourses of public education reform, like that exemplified within the Queensland Government's future vision document, Queensland State Education-2010 (QSE-2010), position schooling as a panacea to pervasive social instability and a means to achieve a new consensus. However, in unravelling the many conflicting statements that conjoin to form…

  1. Atomic polarizabilities

    SciTech Connect

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  2. Comparison of real and idealized cetacean flippers.

    PubMed

    Weber, P W; Murray, M M; Howle, L E; Fish, F E

    2009-12-01

    When a phenomenon in nature is mimicked for practical applications, it is often done so in an idealized fashion, such as representing the shape found in nature with convenient, piece-wise smooth mathematical functions. The aim of idealization is to capture the advantageous features of the natural phenomenon without having to exactly replicate it, and it is often assumed that the idealization process does in fact capture the relevant geometry. We explored the consequences of the idealization process by creating exact scale models of cetacean flippers using CT scans, creating corresponding idealized versions and then determining the hydrodynamic characteristics of the models via water tunnel testing. We found that the majority of the idealized models did not exhibit fluid dynamic properties that were drastically different from those of the real models, although multiple consequences resulting from the idealization process were evident. Drag performance was significantly improved by idealization. Overall, idealization is an excellent way to capture the relevant effects of a phenomenon found in nature, which spares the researcher from having to painstakingly create exact models, although we have found that there are situations where idealization may have unintended consequences such as one model that exhibited a decrease in lift performance.

  3. Observations of density fluctuations in an elongated Bose gas: ideal gas and quasicondensate regimes.

    PubMed

    Esteve, J; Trebbia, J-B; Schumm, T; Aspect, A; Westbrook, C I; Bouchoule, I

    2006-04-07

    We report in situ measurements of density fluctuations in a quasi-one-dimensional 87Rb Bose gas at thermal equilibrium in an elongated harmonic trap. We observe an excess of fluctuations compared to the shot-noise level expected for uncorrelated atoms. At low atomic density, the measured excess is in good agreement with the expected "bunching" for an ideal Bose gas. At high density, the measured fluctuations are strongly reduced compared to the ideal gas case. We attribute this reduction to repulsive interatomic interactions. The data are compared with a calculation for an interacting Bose gas in the quasicondensate regime.

  4. Correlation of ideal and actual shear strengths of metals with their friction properties

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1981-01-01

    The relation between the ideal and actual shear strengths and friction properties of clean metals in contact with clean diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum is discussed. An estimate of the ideal shear strength for metals is obtained from the shear modulus, the repeat distance of atoms in the direction of shear of the metal, and the interplanar spacing of the shearing planes. The coefficient of friction for metals is shown to be correlated with both the ideal and actual shear strength of metals. The higher the strength of the metal, the lower the coefficient of friction occurs.

  5. Should "Teacher Centred Teaching" Replace "Student Centred Learning"?

    ERIC Educational Resources Information Center

    Bailey, Patrick D.

    2008-01-01

    Mission statements of most HEIs across the UK support "student centred learning". In this paper, it is suggested that "teacher centred teaching" should also have a major role to play, improving the quality of the learning experience in higher education. Students are extremely diverse in their skills, weaknesses, and learning…

  6. Should "Teacher Centred Teaching" Replace "Student Centred Learning"?

    ERIC Educational Resources Information Center

    Bailey, Patrick D.

    2008-01-01

    Mission statements of most HEIs across the UK support "student centred learning". In this paper, it is suggested that "teacher centred teaching" should also have a major role to play, improving the quality of the learning experience in higher education. Students are extremely diverse in their skills, weaknesses, and learning…

  7. Ideal stars and General Relativity

    NASA Astrophysics Data System (ADS)

    Frønsdal, Christian

    2007-12-01

    We study a system of differential equations that governs the distribution of matter in the theory of General Relativity. The new element in this paper is the use of a dynamical action principle that includes all the degrees of freedom, matter as well as metric. The matter lagrangian defines a relativistic version of non-viscous, isentropic hydrodynamics. The matter fields are a scalar density and a velocity potential; the conventional, four-vector velocity field is replaced by the gradient of the potential and its scale is fixed by one of the Eulerian equations of motion, an innovation that significantly affects the imposition of boundary conditions. If the density is integrable at infinity, then the metric approaches the Schwarzschild metric at large distances. There are stars without boundary and with finite total mass; the metric shows rapid variation in the neighbourhood of the Schwarzschild radius and there is a very small core where a singularity indicates that the gas laws break down. For stars with boundary there emerges a new, critical relation between the radius and the gravitational mass, a consequence of the stronger boundary conditions. Tentative applications are suggested, to certain Red Giants, and to neutron stars, but the investigation reported here was limited to homogeneous polytropes. Comparison with the results of Oppenheimer and Volkoff on neutron cores shows a close agreement of numerical results. However, in the model the boundary of the star is fixed uniquely by the required matching of the interior metric to the external Schwarzschild metric, which is not the case in the traditional approach. There are solutions for which the metric is very close to the Schwarzshild metric everywhere outside the horizon, where the source is concentrated. The Schwarzschild metric is interpreted as the metric of an ideal, limiting configuration of matter, not as the metric of empty space.

  8. Practicing Identity: A Crafty Ideal?

    NASA Astrophysics Data System (ADS)

    Brysbaert, A.; Vetters, M.

    This paper focuses on the materialization of technological practices as a form of identity expression. Contextual analyses of a Mycenaean workshop area in the Late Bronze Age citadel of Tiryns (Argolis, Greece) are presented to investigate the interaction of different artisans under changing socio-political and economic circumstances. The case study indicates that although certain technological practices are often linked to specific crafts, they do not necessarily imply the separation of job tasks related to the working of one specific material versus another. Shared technological practices and activities, therefore, may be a factor in shaping cohesive group identities of specialized artisans. Since tracing artisans' identities is easier said than done on the basis of excavated materials alone, we employ the concepts of multiple chaînes opératoires combined with cross-craft interactions as a methodology in order to retrieve distinctive sets of both social and technological practices from the archaeological remains. These methodological concepts are not restricted to a specific set of steps in the production cycle, but ideally encompass reconstructing contexts of extraction, manufacture, distribution and discard/reuse for a range of artefacts. Therefore, these concepts reveal both technological practices, and, by contextualising these technological practices in their spatial layout, equally focus on social contacts that would have taken place during any of these actions. Our detailed contextual study demonstrates that the material remains when analysed in their entirety are complementary to textual evidence. In this case study they even form a source of information on palatial spheres of life about which the fragmentary Linear B texts, so far, remain silent.

  9. Improved Classification of Mammograms Following Idealized Training

    PubMed Central

    Hornsby, Adam N.; Love, Bradley C.

    2014-01-01

    People often make decisions by stochastically retrieving a small set of relevant memories. This limited retrieval implies that human performance can be improved by training on idealized category distributions (Giguère & Love, 2013). Here, we evaluate whether the benefits of idealized training extend to categorization of real-world stimuli, namely classifying mammograms as normal or tumorous. Participants in the idealized condition were trained exclusively on items that, according to a norming study, were relatively unambiguous. Participants in the actual condition were trained on a representative range of items. Despite being exclusively trained on easy items, idealized-condition participants were more accurate than those in the actual condition when tested on a range of item types. However, idealized participants experienced difficulties when test items were very dissimilar from training cases. The benefits of idealization, attributable to reducing noise arising from cognitive limitations in memory retrieval, suggest ways to improve real-world decision making. PMID:24955325

  10. Not All Ideals are Equal: Intrinsic and Extrinsic Ideals in Relationships

    PubMed Central

    Rodriguez, Lindsey M.; Hadden, Benjamin W.; Knee, C. Raymond

    2015-01-01

    The ideal standards model suggests that greater consistency between ideal standards and actual perceptions of one’s relationship predicts positive relationship evaluations; however, no research has evaluated whether this differs across types of ideals. A self-determination theory perspective was derived to test whether satisfaction of intrinsic ideals buffers the importance of extrinsic ideals. Participants (N=195) in committed relationships directly and indirectly reported the extent to which their partner met their ideal on two dimensions: intrinsic (e.g., warm, intimate) and extrinsic (e.g., attractive, successful). Relationship need fulfillment and relationship quality were also assessed. Hypotheses were largely supported, such that satisfaction of intrinsic ideals more strongly predicted relationship functioning, and satisfaction of intrinsic ideals buffered the relevance of extrinsic ideals for outcomes. PMID:25821396

  11. The English Teaching Information Centre

    ERIC Educational Resources Information Center

    Roe, Peter

    1977-01-01

    Describes the function of the British Council's English Teaching Information Centre, which serves foreign students, teachers, teacher trainers, scientists, textbook writers, etc. Emphasizes the Centre's work in English for Special Purposes, including an ample library and many services. Address: ETIC, British Council, 10 Spring Gardens, London SW…

  12. CMCC Data Distribution Centre

    NASA Astrophysics Data System (ADS)

    Aloisio, Giovanni; Fiore, Sandro; Negro, A.

    2010-05-01

    The CMCC Data Distribution Centre (DDC) is the primary entry point (web gateway) to the CMCC. It is a Data Grid Portal providing a ubiquitous and pervasive way to ease data publishing, climate metadata search, datasets discovery, metadata annotation, data access, data aggregation, sub-setting, etc. The grid portal security model includes the use of HTTPS protocol for secure communication with the client (based on X509v3 certificates that must be loaded into the browser) and secure cookies to establish and maintain user sessions. The CMCC DDC is now in a pre-production phase and it is currently used only by internal users (CMCC researchers and climate scientists). The most important component already available in the CMCC DDC is the Search Engine which allows users to perform, through web interfaces, distributed search and discovery activities by introducing one or more of the following search criteria: horizontal extent (which can be specified by interacting with a geographic map), vertical extent, temporal extent, keywords, topics, creation date, etc. By means of this page the user submits the first step of the query process on the metadata DB, then, she can choose one or more datasets retrieving and displaying the complete XML metadata description (from the browser). This way, the second step of the query process is carried out by accessing to a specific XML document of the metadata DB. Finally, through the web interface, the user can access to and download (partially or totally) the data stored on the storage device accessing to OPeNDAP servers and to other available grid storage interfaces. Requests concerning datasets stored in deep storage will be served asynchronously.

  13. Ideal and Nonideal Reasoning in Educational Theory

    ERIC Educational Resources Information Center

    Jaggar, Alison M.

    2015-01-01

    The terms "ideal theory" and "nonideal theory" are used in contemporary Anglophone political philosophy to identify alternative methodological approaches for justifying normative claims. Each term is used in multiple ways. In this article Alison M. Jaggar disentangles several versions of ideal and nonideal theory with a view to…

  14. Ideal and Nonideal Reasoning in Educational Theory

    ERIC Educational Resources Information Center

    Jaggar, Alison M.

    2015-01-01

    The terms "ideal theory" and "nonideal theory" are used in contemporary Anglophone political philosophy to identify alternative methodological approaches for justifying normative claims. Each term is used in multiple ways. In this article Alison M. Jaggar disentangles several versions of ideal and nonideal theory with a view to…

  15. Evaluating human enhancements: the importance of ideals.

    PubMed

    Roduit, Johann A R; Baumann, Holger; Heilinger, Jan-Christoph

    2014-01-01

    Is it necessary to have an ideal of perfection in mind to identify and evaluate true biotechnological human "enhancements", or can one do without? To answer this question we suggest employing the distinction between ideal and non-ideal theory, found in the debate in political philosophy about theories of justice: the distinctive views about whether one needs an idea of a perfectly just society or not when it comes to assessing the current situation and recommending steps to increase justice. In this paper we argue that evaluating human enhancements from a non-ideal perspective has some serious shortcomings, which can be avoided when endorsing an ideal approach. Our argument starts from a definition of human enhancement as improvement, which can be understood in two ways. The first approach is backward-looking and assesses improvements with regard to a status quo ante. The second, a forward-looking approach, evaluates improvements with regard to their proximity to a goal or according to an ideal. After outlining the limitations of an exclusively backward-looking view (non-ideal theory), we answer possible objections against a forward-looking view (ideal theory). Ultimately, we argue that the human enhancement debate would lack some important moral insights if a forward-looking view of improvement is not taken into consideration.

  16. Ideals as Anchors for Relationship Experiences

    PubMed Central

    Frye, Margaret; Trinitapoli, Jenny

    2016-01-01

    Research on young-adult sexuality in sub-Saharan Africa typically conceptualizes sex as an individual-level risk behavior. We introduce a new approach that connects the conditions surrounding the initiation of sex with subsequent relationship well-being, examines relationships as sequences of interdependent events, and indexes relationship experiences to individually held ideals. New card-sort data from southern Malawi capture young women’s relationship experiences and their ideals in a sequential framework. Using optimal matching, we measure the distance between ideal and experienced relationship sequences to (1) assess the associations between ideological congruence and perceived relationship well-being, (2) compare this ideal-based approach to other experience-based alternatives, and (3) identify individual- and couple-level correlates of congruence between ideals and experiences in the romantic realm. We show that congruence between ideals and experiences conveys relationship well-being along four dimensions: expressions of love and support, robust communication habits, perceived biological safety, and perceived relationship stability. We further show that congruence is patterned by socioeconomic status and supported by shared ideals within romantic dyads. We argue that conceiving of ideals as anchors for how sexual experiences are manifest advances current understandings of romantic relationships, and we suggest that this approach has applications for other domains of life. PMID:27110031

  17. Maintaining ideal body weight counseling sessions

    SciTech Connect

    Brammer, S.H.

    1980-10-09

    The purpose of this program is to provide employees with the motivation, knowledge and skills necessary to maintain ideal body weight throughout life. The target audience for this program, which is conducted in an industrial setting, is the employee 40 years of age or younger who is at or near his/her ideal body weight.

  18. Three Properties of the Ideal Reader.

    ERIC Educational Resources Information Center

    Kay, Paul

    The main experience of an ideal reader while reading a text is an "envisionment" of that text, a representation in the reader's mind of the content of the text. According to this view the envisionment grows and sometimes changes as the reader progresses through the text, and the ideal reader not only updates and supplements the…

  19. Kirkwood-Buff integrals for ideal solutions

    NASA Astrophysics Data System (ADS)

    Ploetz, Elizabeth A.; Bentenitis, Nikolaos; Smith, Paul E.

    2010-04-01

    The Kirkwood-Buff (KB) theory of solutions is a rigorous theory of solution mixtures which relates the molecular distributions between the solution components to the thermodynamic properties of the mixture. Ideal solutions represent a useful reference for understanding the properties of real solutions. Here, we derive expressions for the KB integrals, the central components of KB theory, in ideal solutions of any number of components corresponding to the three main concentration scales. The results are illustrated by use of molecular dynamics simulations for two binary solutions mixtures, benzene with toluene, and methanethiol with dimethylsulfide, which closely approach ideal behavior, and a binary mixture of benzene and methanol which is nonideal. Simulations of a quaternary mixture containing benzene, toluene, methanethiol, and dimethylsulfide suggest this system displays ideal behavior and that ideal behavior is not limited to mixtures containing a small number of components.

  20. The ideal strength and mechanical hardness of solids

    SciTech Connect

    Krenn, Christopher Robert

    2000-04-01

    Relationships between intrinsic mechanical hardness and atomic-scale properties are reviewed, Hardness scales closely and linearly with shear modulus for a given class of material (covalent, ionic or metallic). A two-parameter fit and a Peierls-stress model produce a more universal scaling relationship, but no model can explain differences in hardness between the transition metal carbides and nitrides. Calculations of ''ideal strength'' (defined by the limit of elastic stability of a perfect crystal) are proposed. The ideal shear strengths of fcc aluminum and copper are calculated using ab initio techniques and allowing for structural relaxation of all five strain components other than the imposed strain. The strengths of Al and Cu are similar (8-9% of the shear modulus), but the geometry of the relaxations in Al and Cu is very different. The relaxations are consistent with experimentally measured third-order elastic constants. The general thermodynamic conditions of elastic stability that set the upper limits of mechanical strength are derived. The conditions of stability are shown for cubic (hydrostatic), tetragonal (tensile) and monoclinic (shear) distortions of a cubic crystal. The implications of this stability analysis to first-principles calculations of ideal strength are discussed, and a method to detect instabilities orthogonal to the direction of the applied stress is identified. The relaxed ideal shear and tensile strengths of bcc tungsten are also calculated using ab initio techniques and are favorably compared to recent nano-indentation measurements. The {100} tensile strength (29.5 GPa) is governed by the Bain instability. The shear strengths in the weak directions on {110}, {112}, and {123} planes are very nearly equal (~ 18 GPa) and occur at approximately the same strain (17-18%). This isotropy is a function of the linear elastic isotropy for shear in directions containing <111> in bcc and of the atomic configurations of energetic saddle points

  1. Atomic Calligraphy

    NASA Astrophysics Data System (ADS)

    Imboden, Matthias; Pardo, Flavio; Bolle, Cristian; Han, Han; Tareen, Ammar; Chang, Jackson; Christopher, Jason; Corman, Benjamin; Bishop, David

    2013-03-01

    Here we present a MEMS based method to fabricate devices with a small number of atoms. In standard semiconductor fabrication, a large amount of material is deposited, after which etching removes what is not wanted. This technique breaks down for structures that approach the single atom limit, as it is inconceivable to etch away all but one atom. What is needed is a bottom up method with single or near single atom precision. We demonstrate a MEMS device that enables nanometer position controlled deposition of gold atoms. A digitally driven plate is swept as a flux of gold atoms passes through an aperture. Appling voltages on four comb capacitors connected to the central plate by tethers enable nanometer lateral precision in the xy plane over 15x15 sq. microns. Typical MEMS structures have manufacturing resolutions on the order of a micron. Using a FIB it is possible to mill apertures as small as 10 nm in diameter. Assuming a low incident atomic flux, as well as an integrated MEMS based shutter with microsecond response time, it becomes possible to deposit single atoms. Due to their small size and low power consumption, such nano-printers can be mounted directly in a cryogenic system at ultrahigh vacuum to deposit clean quench condensed metallic structures.

  2. Atomic supersymmetry

    NASA Technical Reports Server (NTRS)

    Kostelecky, V. Alan

    1993-01-01

    Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models.

  3. RTEMS CENTRE - Support and Maintenance CENTRE to RTEMS Operating System

    NASA Astrophysics Data System (ADS)

    Silva, H.; Constantino, A.; Mota, M.; Freitas, D.; Zulianello, M.

    2007-08-01

    Real Time Operating System for Multiprocessor Systems (RTEMS) CENTRE is a project under the ESA-Portugal Task Force aiming to develop a support and maintenance centre to RTEMS operating system. The project can be summarized in two main streams, first one related to design, development, maintenance and integration of tools to augment and sustain RTEMS operating system and second stream linked to the creation of technical competences with a support site to RTEMS operating system in Europe. RTEMS CENTRE intends to minimize the cost of the incorporation/integration of airborne and space applications in this Real Time Operating System. The centre started officially in the 15th of November 2006 and is currently in the study definition and system engineering phase.

  4. Minister unveils new nanotech centres

    NASA Astrophysics Data System (ADS)

    Dumé, Belle

    2009-06-01

    Three new nanotechnology research centres are to be set up in France as part of a €70m government plan to help French companies in the sector. Researchers at the new centres, which will be located in Grenoble, Saclay (near Paris) and Toulouse, will be encouraged to collaborate with industry to develop new nanotech-based products. Dubbed NANO-INNOV, the new plan includes €46m for two new buildings at Saclay, with the rest being used to buy new equipment at the three centres and to fund grant proposals from staff to the French National Research Agency (ANR).

  5. Sex disparities in ideal cardiovascular health.

    PubMed

    Simon, Marie; Boutouyrie, Pierre; Narayanan, Kumar; Gaye, Bamba; Tafflet, Muriel; Thomas, Frédérique; Guibout, Catherine; Périer, Marie-Cécile; Pannier, Bruno; Jouven, Xavier; Empana, Jean-Philippe

    2017-10-01

    To quantify the gap in the distribution of ideal cardiovascular health (CVH) between men and women accounting for comorbidities, socioeconomic and psychological confounding factors. A cross-sectional analysis was conducted among 9012 French men and women aged 50-75 years who were participants of the Paris Prospective Study 3. Each of the seven metrics was defined according to the American Heart Association criteria, and the CVH was considered as poor (0 or 1 ideal health metric), intermediate (2, 3 or 4 ideal health metrics) and ideal (5-7 ideal health metrics). The odds of intermediate and ideal CVH in women compared with men were estimated by multivariate polytomous logistic regression analysis using poor CVH as the reference category. The mean age was 59.49 year (SD 6.25) and there were 38.54% of women. Though women were slightly older, less educated, more deprived, more often depressed, they were twice more often in ideal CVH than men (14.77% vs 6.84%, p<0.0001). After adjustment for age, deprivation score, education and depression, women were four times more often in ideal CVH (OR 4.01, 95% CI 3.42 to 4.69) and two times more often in intermediate CVH (OR 2.07, 95% CI 1.88 to 2.28) than men. The sex disparities in the prevalence of ideal CVH have the potential to guide sex-specific strategies for improving CVH status in the general population. NCT00741728;Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  6. Research on Non-Ideal Plasmas.

    DTIC Science & Technology

    1978-07-24

    Based on Modified Debye — Huckel Theory (DUO). ... . . . . . . . 107 3.1$ Argon: Mollier Chart for Electrical Con— ductivity Using Rogov’s Asymptotic...are relegated to Section 3 .3 . 3.2.3 The Debye — Huckel Correction to Ideal Gas Theory The Debye — Huckel theory (References 3.1 to 3.14) has been...the same. — 3.2.4 Validity of the Ideal Gas Approximations and the Debye — Huckel Theory The ideal gas approach is based on the presumption that particle

  7. Predicting Film Genres with Implicit Ideals

    PubMed Central

    Olney, Andrew McGregor

    2013-01-01

    We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories. PMID:23423823

  8. Predicting film genres with implicit ideals.

    PubMed

    Olney, Andrew McGregor

    2012-01-01

    We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories.

  9. Force-induced chemical reactions on the metal centre in a single metalloprotein molecule.

    PubMed

    Zheng, Peng; Arantes, Guilherme M; Field, Martin J; Li, Hongbin

    2015-06-25

    Metalloproteins play indispensable roles in biology owing to the versatile chemical reactivity of metal centres. However, studying their reactivity in many metalloproteins is challenging, as protein three-dimensional structure encloses labile metal centres, thus limiting their access to reactants and impeding direct measurements. Here we demonstrate the use of single-molecule atomic force microscopy to induce partial unfolding to expose metal centres in metalloproteins to aqueous solution, thus allowing for studying their chemical reactivity in aqueous solution for the first time. As a proof-of-principle, we demonstrate two chemical reactions for the FeS4 centre in rubredoxin: electrophilic protonation and nucleophilic ligand substitution. Our results show that protonation and ligand substitution result in mechanical destabilization of the FeS4 centre. Quantum chemical calculations corroborated experimental results and revealed detailed reaction mechanisms. We anticipate that this novel approach will provide insights into chemical reactivity of metal centres in metalloproteins under biologically more relevant conditions.

  10. Radiotherapy capacity in European countries: an analysis of the Directory of Radiotherapy Centres (DIRAC) database.

    PubMed

    Rosenblatt, Eduardo; Izewska, Joanna; Anacak, Yavuz; Pynda, Yaroslav; Scalliet, Pierre; Boniol, Mathieu; Autier, Philippe

    2013-02-01

    Radiotherapy is used for cure or palliation in around half of patients with cancer. We analysed data on radiotherapy equipment in 33 European countries registered in the Directory of Radiotherapy Centres (DIRAC) database, managed by the International Atomic Energy Agency. As of July, 2012, Europe had 1286 active radiotherapy centres. The average number of teletherapy machines per radiotherapy centre ranged from 1·2 to 7·0 in different countries. Nordic countries, the UK, the Netherlands, and Slovenia all have large centres with four to ten teletherapy machines. Most western and southern European countries have several small centres with one or two machines, with few larger centres. The fragmentation in radiotherapy services that prevails in many European countries might affect the economic burden of radiotherapy and its quality. Eastern and southeastern European countries need to expand and modernise their radiotherapy equipment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Atomic resolution holography.

    PubMed

    Hayashi, Kouichi

    2014-11-01

    Atomic resolution holography, such as X-ray fluorescence holography (XFH)[1] and photoelectron holography (PH), has the attention of researcher as an informative local structure analysis, because it provides three dimensional atomic images around specific elements within a range of a few nanometers. It can determine atomic arrangements around a specific element without any prior knowledge of structures. It is considered that the atomic resolution holographic is a third method of structural analysis at the atomic level after X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). As known by many researchers, XRD and XAFS are established methods that are widespread use in various fields. XRD and XAFS provide information on long-range translational periodicities and very local environments, respectively, whereas the atomic resolution holography gives 3D information on the local order and can visualize surrounding atoms with a large range of coordination shells. We call this feature "3D medium-range local structure observation".In addition to this feature, the atomic resolution holography is very sensitive to the displacement of atoms from their ideal positions, and one can obtain quantitative information about local lattice distortions by analyzing reconstructed atomic images[2] When dopants with different atomic radii from the matrix elements are present, the lattices around the dopants are distorted. However, using the conventional methods of structural analysis, one cannot determine the extent to which the local lattice distortions are preserved from the dopants. XFH is a good tool for solving this problem.Figure 1 shows a recent achievement on a relaxor ferroelectric of Pb(Mg1/3Nb2/3)O3 (PMN) using XFH. The structural studies of relaxor ferroelectrics have been carried out by X-ray or neutron diffractions, which suggested rhombohedral distortions of their lattices. However, their true pictures have not been obtained, yet. The Nb Kα holograms showed

  12. Maria Goeppert Mayer: atoms, molecules and nuclear shells

    SciTech Connect

    Johnson, K.E.

    1986-09-01

    The mathematical physicist's early work in atomic and molecular physics, and her unfamiliarity with the ''fashions'' in nuclear physics, gave her the ideal preparation for solving the puzzle of the nuclear ''magic numbers.''

  13. Optimal shortcuts for atomic transport in anharmonic traps

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Muga, J. G.; Guéry-Odelin, D.; Chen, Xi

    2016-06-01

    We design fast trap trajectories to transport cold atoms in anharmonic traps, combining invariant-based inverse engineering, perturbation theory, and optimal control theory. Among the ideal trajectories for harmonic traps, we choose the ones that minimize the anharmonic energy.

  14. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  15. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  16. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  17. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  18. Ideal Gas Laws: Experiments for General Chemistry

    ERIC Educational Resources Information Center

    Deal, Walter J.

    1975-01-01

    Describes a series of experiments designed to verify the various relationships implicit in the ideal gas equation and shows that the success of the Graham's law effusion experiments can be explained by elementary hydrodynamics. (GS)

  19. Ideals and Realities of the Olympic Games

    ERIC Educational Resources Information Center

    Hibler, Richard W.

    1976-01-01

    With the growth of professionalism and the emphasis on money in sports, modern society is losing sight of the ideals of style and grace that were of primary importance in the early Olympic games. nJD)

  20. Medical learning curves and the Kantian ideal

    PubMed Central

    Le Morvan, P; Stock, B

    2005-01-01

    A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice. PMID:16131552

  1. Ideal Gas Laws: Experiments for General Chemistry

    ERIC Educational Resources Information Center

    Deal, Walter J.

    1975-01-01

    Describes a series of experiments designed to verify the various relationships implicit in the ideal gas equation and shows that the success of the Graham's law effusion experiments can be explained by elementary hydrodynamics. (GS)

  2. A simple probabilistic model of ideal gases

    NASA Astrophysics Data System (ADS)

    Sossinsky, A. B.

    2016-01-01

    We describe a discrete 3D model of ideal gas based on the idea that, on the microscopic level, the particles move randomly (as in ASEP models), instead of obeying Newton's laws as prescribed by Boltzmann.

  3. Decomposition theorem in ideal topological spaces

    NASA Astrophysics Data System (ADS)

    AL-omeri, W.; Noorani, Mohd. Salmi; AL-Omari, A.

    2014-06-01

    We introduce new classes of sets called a* -I -open,A-β-I-open sets, A-pre* -I-open sets, strongly T-I -sets, A-β-T-I-sets, strongly BA -I -sets, BA -I -sets, and δβA -I -open sets in ideal topological spaces. Using these sets, to obtain decompositions of continuity in an ideal topological space.

  4. Three special classes of Wintgen ideal submanifolds

    NASA Astrophysics Data System (ADS)

    Xie, Zhenxiao

    2017-04-01

    Wintgen ideal submanifolds in space forms are those ones attaining equality pointwise in the so-called DDVV inequality which relates the scalar curvature, the mean curvature and the normal scalar curvature. In this paper, we investigate three special classes of Wintgen ideal submanifolds: the ones with constant mean curvature, the ones with constant scalar curvature and the ones with constant normal scalar curvature. Some characterization results are given.

  5. Ideal shrinking and expansion of discrete sequences

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    1986-01-01

    Ideal methods are described for shrinking or expanding a discrete sequence, image, or image sequence. The methods are ideal in the sense that they preserve the frequency spectrum of the input up to the Nyquist limit of the input or output, whichever is smaller. Fast implementations that make use of the discrete Fourier transform or the discrete Hartley transform are described. The techniques lead to a new multiresolution image pyramid.

  6. Asymptotic properties of path integral ideals

    SciTech Connect

    Bogojevic, A.; Balaz, A.; Belic, A.

    2005-09-01

    We introduce and analyze an interesting quantity, the path integral ideal, governing the flow of generic discrete theories to the continuum limit and greatly increasing their convergence. The said flow is classified according to the degree of divergence of the potential at spatial infinity. Studying the asymptotic behavior of path integral ideals we isolate the dominant terms in the effective potential that determine the behavior of a generic theory for large discrete time steps.

  7. Guiding center equations for ideal magnetohydrodynamic modes

    SciTech Connect

    White, R. B.

    2013-04-15

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B-vector={nabla} Multiplication-Sign ({xi}-vector Multiplication-Sign B-vector), however, perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories, the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement {xi}-vector are derived which preserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  8. The Statistical Mechanics of Ideal MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2003-01-01

    Turbulence is a universal, nonlinear phenomenon found in all energetic fluid and plasma motion. In particular. understanding magneto hydrodynamic (MHD) turbulence and incorporating its effects in the computation and prediction of the flow of ionized gases in space, for example, are great challenges that must be met if such computations and predictions are to be meaningful. Although a general solution to the "problem of turbulence" does not exist in closed form, numerical integrations allow us to explore the phase space of solutions for both ideal and dissipative flows. For homogeneous, incompressible turbulence, Fourier methods are appropriate, and phase space is defined by the Fourier coefficients of the physical fields. In the case of ideal MHD flows, a fairly robust statistical mechanics has been developed, in which the symmetry and ergodic properties of phase space is understood. A discussion of these properties will illuminate our principal discovery: Coherent structure and randomness co-exist in ideal MHD turbulence. For dissipative flows, as opposed to ideal flows, progress beyond the dimensional analysis of Kolmogorov has been difficult. Here, some possible future directions that draw on the ideal results will also be discussed. Our conclusion will be that while ideal turbulence is now well understood, real turbulence still presents great challenges.

  9. Guiding Center Equations for Ideal Magnetohydrodynamic Modes

    SciTech Connect

    Roscoe B. White

    2013-02-21

    Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through δ~B = ∇ X (ξ X B) however perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement ξ are derived which perserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

  10. Molecular determinants of cadherin ideal bond formation: Conformation-dependent unbinding on a multidimensional landscape

    PubMed Central

    Manibog, Kristine; Sankar, Kannan; Kim, Sun-Ae; Zhang, Yunxiang; Jernigan, Robert L.; Sivasankar, Sanjeevi

    2016-01-01

    Classical cadherin cell–cell adhesion proteins are essential for the formation and maintenance of tissue structures; their primary function is to physically couple neighboring cells and withstand mechanical force. Cadherins from opposing cells bind in two distinct trans conformations: strand-swap dimers and X-dimers. As cadherins convert between these conformations, they form ideal bonds (i.e., adhesive interactions that are insensitive to force). However, the biophysical mechanism for ideal bond formation is unknown. Here, we integrate single-molecule force measurements with coarse-grained and atomistic simulations to resolve the mechanistic basis for cadherin ideal bond formation. Using simulations, we predict the energy landscape for cadherin adhesion, the transition pathways for interconversion between X-dimers and strand-swap dimers, and the cadherin structures that form ideal bonds. Based on these predictions, we engineer cadherin mutants that promote or inhibit ideal bond formation and measure their force-dependent kinetics using single-molecule force-clamp measurements with an atomic force microscope. Our data establish that cadherins adopt an intermediate conformation as they shuttle between X-dimers and strand-swap dimers; pulling on this conformation induces a torsional motion perpendicular to the pulling direction that unbinds the proteins and forms force-independent ideal bonds. Torsional motion is blocked when cadherins associate laterally in a cis orientation, suggesting that ideal bonds may play a role in mechanically regulating cadherin clustering on cell surfaces. PMID:27621473

  11. The digital eczema centre utrecht.

    PubMed

    van Os-Medendorp, Harmieke; van Veelen, Carien; Hover, Maaike; Eland-de Kok, Petra; Bruijnzeel-Koomen, Carla; Sonnevelt, Gert-Jan; Mensing, Geert; Pasmans, Suzanne

    2010-01-01

    The University Medical Centre Utrecht (UMC Utrecht) has developed an eczema portal that combines e-consulting, monitoring and self-management training by a dermatology nurse online for patients and parents of young children with atopic dermatitis (AD). Patient satisfaction with the portal was high. It could be extended to become a Digital Eczema Centre for multidisciplinary collaboration between health-care providers from different locations and the patient. Before starting the construction of the Digital Eczema Centre, the feasibility was examined by carrying out a business case analysis. The purposes, strength and weaknesses showed that the Digital Eczema Centre offered opportunities to improve care for patients with AD. The financial analysis resulted in a medium/best case scenario with a positive result of euro50-240,000 over a period of five years. We expect that the Digital Eczema Centre will increase the accessibility and quality of care. The web-based patient record and the digital chain-of-care promote the involvement of patients, parents and multidisciplinary teams as well as the continuity and coordination of care.

  12. Atomic research

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.; Connatser, Robert; Cothren, Bobby; Johnson, R. B.

    1993-01-01

    Work performed by the University of Alabama in Huntsville's (UAH) Center for Applied Optics (CAO) entitled Atomic Research is documented. Atomic oxygen (AO) effects on materials have long been a critical concern in designing spacecraft to withstand exposure to the Low Earth Orbit (LEO) environment. The objective of this research effort was to provide technical expertise in the design of instrumentation and experimental techniques for analyzing materials exposed to atomic oxygen in accelerated testing at NASA/MSFC. Such testing was required to answer fundamental questions concerning Space Station Freedom (SSF) candidate materials and materials exposed to atomic oxygen aboard the Long-Duration Exposure Facility (LDEF). The primary UAH task was to provide technical design, review, and analysis to MSFC in the development of a state-of-the-art 5eV atomic oxygen beam facility required to simulate the RAM-induced low earth orbit (LEO) AO environment. This development was to be accomplished primarily at NASA/MSFC. In support of this task, contamination effects and ultraviolet (UV) simulation testing was also to be carried out using NASA/MSFC facilities. Any materials analysis of LDEF samples was to be accomplished at UAH.

  13. Laser Trapping of Radioactive Atoms

    NASA Astrophysics Data System (ADS)

    Lu, Zheng-Tian

    2013-04-01

    Stuart Freedman conceived the idea of laser trapping radioactive atoms for the purpose of studying beta correlation effects. ``This is really the theorist's view of a radioactive source,'' as he fondly claimed. It is ideal because the atoms form a point source, compressed in both position and momentum space, with no material walls nearby. The Berkeley group succeeded in trapping ^21Na (half-life = 22 s) atoms [Lu et al., PRL 72, 3791 (1994)], and determined its beta-neutrino correlation coefficient a=0.5502(60) to be in agreement with the Standard Model [Vetter et al., PRC 77, 035502 (2008)]. Other groups have joined this effort with searches for scalar or tensor couplings in the weak interaction. Moreover, the technique has been extended to trap very short lived ^8He (0.1 s) to study its halo structure or the very long lived ^81Kr (230,000 yr) to map the movement of groundwater.

  14. Person-centred reflective practice.

    PubMed

    Devenny, Bob; Duffy, Kathleen

    Person-centred health and person-centred care have gained prominence across the UK following the publication of reports on public inquiries exploring failings in care. Self-awareness and participation in reflective practice are recognised as vital to supporting the person-centred agenda. This article presents an education framework for reflective practice, developed and used in one NHS board in Scotland, and based on the tenets of the clinical pastoral education movement. Providing an insight into the usefulness of a spiritual component in the reflective process, the framework provides an opportunity for nurses and other healthcare professionals to examine the spiritual dimensions of patient encounters, their own values and beliefs, and the effect these may have on their practice.

  15. Atom Interferometry

    ScienceCinema

    Mark Kasevich

    2016-07-12

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  16. Atom Interferometry

    SciTech Connect

    Mark Kasevich

    2008-05-07

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  17. Atom Interferometry

    SciTech Connect

    Kasevich, Mark

    2008-05-08

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton's constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gyroscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be used to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  18. Adjoint sensitivity study on idealized explosive cyclogenesis

    NASA Astrophysics Data System (ADS)

    Chu, Kekuan; Zhang, Yi

    2016-06-01

    The adjoint sensitivity related to explosive cyclogenesis in a conditionally unstable atmosphere is investigated in this study. The PSU/NCAR limited-area, nonhydrostatic primitive equation numerical model MM5 and its adjoint system are employed for numerical simulation and adjoint computation, respectively. To ensure the explosive development of a baroclinic wave, the forecast model is initialized with an idealized condition including an idealized two-dimensional baroclinic jet with a balanced three-dimensional moderate-amplitude disturbance, derived from a potential vorticity inversion technique. Firstly, the validity period of the tangent linear model for this idealized baroclinic wave case is discussed, considering different initial moisture distributions and a dry condition. Secondly, the 48-h forecast surface pressure center and the vertical component of the relative vorticity of the cyclone are selected as the response functions for adjoint computation in a dry and moist environment, respectively. The preliminary results show that the validity of the tangent linear assumption for this idealized baroclinic wave case can extend to 48 h with intense moist convection, and the validity period can last even longer in the dry adjoint integration. Adjoint sensitivity analysis indicates that the rapid development of the idealized baroclinic wave is sensitive to the initial wind and temperature perturbations around the steering level in the upstream. Moreover, the moist adjoint sensitivity can capture a secondary high sensitivity center in the upper troposphere, which cannot be depicted in the dry adjoint run.

  19. Numerical estimates for the bulk viscosity of ideal gases

    NASA Astrophysics Data System (ADS)

    Cramer, M. S.

    2012-06-01

    We estimate the bulk viscosity of a selection of well known ideal gases. A relatively simple formula is combined with published values of rotational and vibrational relaxation times. It is shown that the bulk viscosity can take on a wide variety of numerical values and variations with temperature. Several fluids, including common diatomic gases, are seen to have bulk viscosities which are hundreds or thousands of times larger than their shear viscosities. We have also provided new estimates for the bulk viscosity of water vapor in the range 380-1000 K. We conjecture that the variation of bulk viscosity with temperature will have a local maximum for most fluids. The Lambert-Salter correlation is used to argue that the vibrational contribution to the bulk viscosities of a sequence of fluids having a similar number of hydrogen atoms at a fixed temperature will increase with the characteristic temperature of the lowest vibrational mode.

  20. Ideally Hexagonally Ordered TiO2 Nanotube Arrays

    PubMed Central

    Sopha, Hanna; Samoril, Tomas; Palesch, Erik; Hromadko, Ludek; Zazpe, Raul; Skoda, David; Urbanek, Michal; Ng, Siowwoon; Prikryl, Jan

    2017-01-01

    Abstract Ideally hexagonally ordered TiO2 nanotube layers were produced through the optimized anodization of Ti substrates. The Ti substrates were firstly covered with a TiN protecting layer prepared through atomic layer deposition (ALD). Pre‐texturing of the TiN‐protected Ti substrate on an area of 20×20 μm2 was carried out by focused ion beam (FIB) milling, yielding uniform nanoholes with a hexagonal arrangement throughout the TiN layer with three different interpore distances. The subsequent anodic nanotube growth using ethylene‐glycol‐based electrolyte followed the pre‐textured nanoholes, resulting in perfectly ordered nanotube layers (resembling honeycomb porous anodic alumina) without any point defects and with a thickness of approximately 2 μm over the whole area of the pattern. PMID:28794939

  1. Temperature effect on ideal shear strength of Al and Cu

    NASA Astrophysics Data System (ADS)

    Iskandarov, Albert M.; Dmitriev, Sergey V.; Umeno, Yoshitaka

    2011-12-01

    According to Frenkel’s estimation, at critical shear stress τc=G/2π, where G is the shear modulus, plastic deformation or fracture is initiated even in defect-free materials. In the past few decades it was realized that, if material strength is probed at the nanometer scale, it can be close to the theoretical limit, τc. The weakening effect of the free surface and other factors has been discussed in the literature, but the effect of temperature on the ideal strength of metals has not been addressed thus far. In the present study, we perform molecular dynamics simulations to estimate the temperature effect on the ideal shear strength of two fcc metals, Al and Cu. Shear parallel to the close-packed (111) plane along the [112¯] direction is studied at temperatures up to 800 K using embedded atom method potentials. At room temperature, the ideal shear strength of Al (Cu) is reduced by 25% (22%) compared to its value at 0 K. For both metals, the shear modulus, G, and the critical shear stress at which the stacking fault is formed, τc, decrease almost linearly with increasing temperature. The ratio G/τc linearly increases with increasing temperature, meaning that τc decreases with temperature faster than G. Critical shear strain, γc, also decreases with temperature, but in a nonlinear fashion. The combination of parameters, Gγc/τc, introduced by Ogata as a generalization of Frenkel’s formula, was found to be almost independent of temperature. We also discuss the simulation cell size effect and compare our results with the results of abinitio calculations and experimental data.

  2. Reality television and the muscular male ideal.

    PubMed

    Dallesasse, Starla L; Kluck, Annette S

    2013-06-01

    Although researchers have examined the negative effects of viewing reality television (RTV) on women's body image, this research has not been extended to men. Exploring the extent to which RTV depicts men who embody the muscular ideal may enhance our understanding of the potential influence of this media genre. We explored the extent to which RTV depicted men who embodied the muscular ideal using a quantitative content analysis. Based on binomial tests, the primary male cast members of programs airing on networks popular among young adult men during the Fall 2009 broadcast season were more muscular, with lower levels of body fat, than average U.S. men. The chest-to-waist and shoulder-to-waist ratios of these cast members did not differ as a function of program type (i.e., reality drama, endurance, and romance). Young men who view RTV programs included in the present study would be exposed to an unrepresentative muscular ideal. Published by Elsevier Ltd.

  3. Ideals versus reality: Are weight ideals associated with weight change in the population?

    PubMed

    Kärkkäinen, Ulla; Mustelin, Linda; Raevuori, Anu; Kaprio, Jaakko; Keski-Rahkonen, Anna

    2016-04-01

    To quantify weight ideals of young adults and to examine whether the discrepancy between actual and ideal weight is associated with 10-year body mass index (BMI) change in the population. This study comprised 4,964 adults from the prospective population-based FinnTwin16 study. They reported their actual and ideal body weight at age 24 (range 22-27) and 10 years later (attrition 24.6%). The correlates of discrepancy between actual and ideal body weight and the impact on subsequent BMI change were examined. The discrepancy between actual and ideal weight at 24 years was on average 3.9 kg (1.4 kg/m(2) ) among women and 1.2 kg (0.4 kg/m(2) ) among men. On average, participants gained weight during follow-up irrespective of baseline ideal weight: women ¯x = +4.8 kg (1.7 kg/m(2) , 95% CI 1.6-1.9 kg/m(2) ), men ¯x = +6.3 kg (2.0 kg/m(2) , 95% CI 1.8-2.1 kg/m(2) ). Weight ideals at 24 years were not correlated with 10-year weight change. At 34 years, just 13.2% of women and 18.9% of men were at or below the weight they had specified as their ideal weight at 24 years. Women and men adjusted their ideal weight upward over time. Irrespective of ideal weight at baseline, weight gain was nearly universal. Weight ideals were shifted upward over time. © 2016 The Obesity Society.

  4. Laser Cooling and Trapping of Neutral Atoms

    DTIC Science & Technology

    1992-07-01

    that the fraction of atoms in the excited state was not muci different for the two conditions. Our experimental procedure turned out to be ideal for...the storage of more matrix elements than is possible with the available computer memory . The high degree of localization already measured in the

  5. Primitive ideals of C q [ SL(3)

    NASA Astrophysics Data System (ADS)

    Hodges, Timothy J.; Levasseur, Thierry

    1993-10-01

    The primitive ideals of the Hopf algebra C q [ SL(3)] are classified. In particular it is shown that the orbits in Prim C q [ SL(3)] under the action of the representation group H ≅ C *× C * are parameterized naturally by W×W, where W is the associated Weyl group. It is shown that there is a natural one-to-one correspondence between primitive ideals of C q [ SL(3)] and symplectic leaves of the associated Poisson algebraic group SL(3, C).

  6. Analysis of an idealized Stirling thermocompressor

    SciTech Connect

    Kornhauser, A.A.

    1996-12-31

    A thermocompressor uses thermal energy to increase the pressure of a fluid without the intermediate production of mechanical work. The thermocompressor described here is essentially a cold-connected Gamma Stirling engine with the power cylinder replaced by inlet and discharge check valves. It is analyzed based on assumptions similar to those made in the analysis of an ideal Stirling engine. The analysis gives closed form predictions for thermocompressor thermal efficiency, volumetric efficiency, and non-dimensional heat input as functions of pressure and temperature ratio. It is also used to compare thermocompressor performance to that of an ideal Otto engine-driven mechanical compressor.

  7. Questioning Centre-Periphery Platforms

    ERIC Educational Resources Information Center

    Postiglione, Gerard A.

    2005-01-01

    How much is hegemony and how much is self-determination in the higher education systems in Southeast Asia? This paper argues that while the question of centre and periphery is still relevant to the analysis of international university systems, the analytical frameworks from which it has arisen may lose viability in the long term. Southeast Asian…

  8. The Tehran Book Processing Centre.

    ERIC Educational Resources Information Center

    Harvey, John F.

    Establishment of the Tehran Book Processing Centre (Tebroc) was proposed in the Spring of 1968. This document is a descriptive and historical account of the center, and a description of its contributions to Iranian processing development. The center was modeled, to a certain extent, after Bro-Dart's Alanar in Williamsport, Pennsylvania. Tebroc was…

  9. Reliability-centred approach evaluated.

    PubMed

    Steele, William R

    2005-02-01

    Reliability-centred maintenance is the process used to determine the most effective maintenance approach. RCM takes a system approach when evaluating the consequences of failure. Run-to-fail is sometimes an acceptable maintenance approach. Condition monitoring is often the most effective maintenance approach.

  10. Bright optical centre in diamond with narrow, highly polarised and nearly phonon-free fluorescence at room temperature

    NASA Astrophysics Data System (ADS)

    John, Roger; Lehnert, Jan; Mensing, Michael; Spemann, Daniel; Pezzagna, Sébastien; Meijer, Jan

    2017-05-01

    Using shallow implantation of ions and molecules with masses centred at 27 atomic mass units (amu) in diamond, a new artificial optical centre with unique properties has been created. The centre shows a linearly polarised fluorescence with a main narrow emission line mostly found at 582 nm, together with a weak vibronic sideband at room temperature. The fluorescence lifetime is ∼2 ns and the brightest centres are more than three times brighter than the nitrogen-vacancy centres. A majority of the centres shows stable fluorescence whereas some others present a blinking behaviour, at faster or slower rates. Furthermore, a second kind of optical centre has been simultaneously created in the same diamond sample, within the same ion implantation run. This centre has a narrow zero-phonon line (ZPL) at ∼546 nm and a broad phonon sideband at room temperature. Interestingly, optically detected magnetic resonance (ODMR) has been measured on several single 546 nm centres and two resonance peaks are found at 0.99 and 1.27 GHz. In view of their very similar ODMR and optical spectra, the 546 nm centre is likely to coincide with the ST1 centre, reported once (with a ZPL at 550 nm), but of still unknown nature. These new kinds of centres are promising for quantum information processing, sub-diffraction optical imaging or use as single-photon sources.

  11. Simulation of turbulent flow over idealized water waves

    NASA Astrophysics Data System (ADS)

    Sullivan, Peter P.; McWilliams, James C.; Moeng, Chin-Hoh

    2000-02-01

    Turbulent flow over idealized water waves with varying wave slope ak and wave age c/u[low asterisk] is investigated using direct numerical simulations at a bulk Reynolds number Re = 8000. In the present idealization, the shape of the water wave and the associated orbital velocities are prescribed and do not evolve dynamically under the action of the wind. The results show that the imposed waves significantly influence the mean flow, vertical momentum fluxes, velocity variances, pressure, and form stress (drag). Compared to a stationary wave, slow (fast) moving waves increase (decrease) the form stress. At small c/u[low asterisk], waves act similarly to increasing surface roughness zo resulting in mean vertical velocity profiles with shorter buffer and longer logarithmic regions. With increasing wave age, zo decreases so that the wavy lower surface is nearly as smooth as a flat lower boundary. Vertical profiles of turbulence statistics show that the wave effects depend on wave age and wave slope but are confined to a region kz < 1 (where k is the wavenumber of the surface undulation and z is the vertical coordinate). The turbulent momentum flux can be altered by as much as 40% by the waves. A region of closed streamlines (or cat's-eye pattern) centred about the critical layer height was found to be dynamically important at low to moderate values of c/u[low asterisk]. The wave-correlated velocity and flux fields are strongly dependent on the variation of the critical layer height and to a lesser extent the surface orbital velocities. Above the critical layer zcr the positions of the maximum and minimum wave-correlated vertical velocity ww occur upwind and downwind of the peak in zcr, like a stationary surface. The wave-correlated flux uwww is positive (negative) above (below) the critical layer height.

  12. Simple correlation for predicting detonation velocity of ideal and non-ideal explosives.

    PubMed

    Keshavarz, Mohammad Hossein

    2009-07-30

    This paper describes a simple method for prediction of detonation velocity of ideal and non-ideal explosives. A non-ideal aluminized and nitrated explosive can have Chapman-Jouguet detonation velocity significantly different from that expected from existing thermodynamic computer codes for equilibrium and steady-state calculations. Detonation velocity of explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from values of a, b, c, d, e and a specific structural parameter without using any assumed detonation products, heat of formation and experimental data. Predicted detonation velocities by this procedure for ideal and non-ideal explosives show good agreement with respect to experimental values as compared to computed results of BKWR and BKWS equations of state.

  13. Reading and writing single-atom magnets.

    PubMed

    Natterer, Fabian D; Yang, Kai; Paul, William; Willke, Philip; Choi, Taeyoung; Greber, Thomas; Heinrich, Andreas J; Lutz, Christopher P

    2017-03-08

    The single-atom bit represents the ultimate limit of the classical approach to high-density magnetic storage media. So far, the smallest individually addressable bistable magnetic bits have consisted of 3-12 atoms. Long magnetic relaxation times have been demonstrated for single lanthanide atoms in molecular magnets, for lanthanides diluted in bulk crystals, and recently for ensembles of holmium (Ho) atoms supported on magnesium oxide (MgO). These experiments suggest a path towards data storage at the atomic limit, but the way in which individual magnetic centres are accessed remains unclear. Here we demonstrate the reading and writing of the magnetism of individual Ho atoms on MgO, and show that they independently retain their magnetic information over many hours. We read the Ho states using tunnel magnetoresistance and write the states with current pulses using a scanning tunnelling microscope. The magnetic origin of the long-lived states is confirmed by single-atom electron spin resonance on a nearby iron sensor atom, which also shows that Ho has a large out-of-plane moment of 10.1 ± 0.1 Bohr magnetons on this surface. To demonstrate independent reading and writing, we built an atomic-scale structure with two Ho bits, to which we write the four possible states and which we read out both magnetoresistively and remotely by electron spin resonance. The high magnetic stability combined with electrical reading and writing shows that single-atom magnetic memory is indeed possible.

  14. Reading and writing single-atom magnets

    NASA Astrophysics Data System (ADS)

    Natterer, Fabian D.; Yang, Kai; Paul, William; Willke, Philip; Choi, Taeyoung; Greber, Thomas; Heinrich, Andreas J.; Lutz, Christopher P.

    2017-03-01

    The single-atom bit represents the ultimate limit of the classical approach to high-density magnetic storage media. So far, the smallest individually addressable bistable magnetic bits have consisted of 3–12 atoms. Long magnetic relaxation times have been demonstrated for single lanthanide atoms in molecular magnets, for lanthanides diluted in bulk crystals, and recently for ensembles of holmium (Ho) atoms supported on magnesium oxide (MgO). These experiments suggest a path towards data storage at the atomic limit, but the way in which individual magnetic centres are accessed remains unclear. Here we demonstrate the reading and writing of the magnetism of individual Ho atoms on MgO, and show that they independently retain their magnetic information over many hours. We read the Ho states using tunnel magnetoresistance and write the states with current pulses using a scanning tunnelling microscope. The magnetic origin of the long-lived states is confirmed by single-atom electron spin resonance on a nearby iron sensor atom, which also shows that Ho has a large out-of-plane moment of 10.1 ± 0.1 Bohr magnetons on this surface. To demonstrate independent reading and writing, we built an atomic-scale structure with two Ho bits, to which we write the four possible states and which we read out both magnetoresistively and remotely by electron spin resonance. The high magnetic stability combined with electrical reading and writing shows that single-atom magnetic memory is indeed possible.

  15. Ideal Sowing Depth for Sweetgum Seed

    Treesearch

    F. T. Bonner

    1967-01-01

    This paper reports the sowing depths from which sweetgum (Liquidambar styraciflua L.) seedlings can emerge under near ideal conditions. Little is known about the seedbed conditions required for successful direct seeding of sweetgum, and the information presented here will be useful in planning field trials.

  16. Ideal light concentrators with reflector gaps

    DOEpatents

    Winston, Roland

    1980-01-01

    A cylindrical or trough-like radiant energy concentration and collection device is provided. The device includes an energy absorber, a glazing enveloping the absorber and a reflective wall. The ideal contour of the reflective wall is determined with reference to a virtual absorber and not the actual absorber cross section.

  17. Memory and Ideals in French Classrooms.

    ERIC Educational Resources Information Center

    Anderson-Levitt, Kathryn M.

    French elementary school teachers as well as the parents of their pupils remember being quiet students in teacher-dominated classrooms. Yet today both teachers and parents idealize lively classroom participation by their pupils or children. In this study, teachers and parents in an urban school district in Villefleurie, France, watched videotaped…

  18. Real vs. Ideal Self Discrepancy in Bulimics.

    ERIC Educational Resources Information Center

    Kosak, Karen

    Bulimia is an eating disorder prevalent among young women, characterized by binge eating episodes followed by purging with subsequent depressive moods and self-deprecating thoughts. To determine whether bulimic women exhibit a greater discrepancy between their perceived and ideal selves than do nonbulimics, three samples of women were assessed.…

  19. Water: The Ideal Early Learning Environment

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2008-01-01

    Bathtubs and swimming pools provide the ideal learning environment for people with special needs. For young preschool children, the activities that take place through water can help them develop physical fitness, facilitate motor development, reinforce perceptual-motor ability, encourage social development, and enhance self-esteem and confidence.…

  20. The Heat Capacity of Ideal Gases

    ERIC Educational Resources Information Center

    Scott, Robert L.

    2006-01-01

    The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves…

  1. Ideal orifice pulse tube refrigerator performance

    NASA Technical Reports Server (NTRS)

    Kittel, P.

    1992-01-01

    The recent development of orifice pulse tube refrigerators has raised questions as to what limits their ultimate performance. Using an analogy to the Stirling cycle refrigerator, the efficiency (cooling power per unit input power) of an ideal orifice pulse tube refrigerator is shown to be T1/T0, the ratio of the cold temperature to the hot temperature.

  2. Black teachers' perceptions of the ideal pupil.

    PubMed

    Kaltsounis, B; Higdon, G

    1977-12-01

    Torrance's Ideal Child Checklist was administered to 76 black teachers. A comparison of their 10 most and least valued traits with those of the expert panel on the creative personality showed that the two groups agreed only once on the 10 most valued traits and three times on the 10 least valued traits.

  3. The Heat Capacity of Ideal Gases

    ERIC Educational Resources Information Center

    Scott, Robert L.

    2006-01-01

    The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves…

  4. The World Grant Ideal and Engagement Scholarship

    ERIC Educational Resources Information Center

    Fitzgerald, Hiram E.; Simon, Lou Anna K.

    2012-01-01

    Michigan State University President Lou Anna Simon's concept of the world grant ideal is grounded in three core values: quality, inclusiveness, and connectivity. These core values fuel the 21st-century imperative to build sustainable global prosperity. They represent an affirmation of the Morrill Act of 1862 in the context of a global society and…

  5. How Is the Ideal Gas Law Explanatory?

    ERIC Educational Resources Information Center

    Woody, Andrea I.

    2013-01-01

    Using the ideal gas law as a comparative example, this essay reviews contemporary research in philosophy of science concerning scientific explanation. It outlines the inferential, causal, unification, and erotetic conceptions of explanation and discusses an alternative project, the functional perspective. In each case, the aim is to highlight…

  6. Water: The Ideal Early Learning Environment

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2008-01-01

    Bathtubs and swimming pools provide the ideal learning environment for people with special needs. For young preschool children, the activities that take place through water can help them develop physical fitness, facilitate motor development, reinforce perceptual-motor ability, encourage social development, and enhance self-esteem and confidence.…

  7. Derivation of the Ideal Gas Law

    ERIC Educational Resources Information Center

    Laugier, Alexander; Garai, Jozsef

    2007-01-01

    Undergraduate and graduate physics and chemistry books usually state that combining the gas laws results in the ideal gas law. Leaving the derivation to the students implies that this should be a simple task, most likely a substitution. Boyle's law, Charles's law, and the Avogadro's principle are given under certain conditions; therefore, direct…

  8. How Is the Ideal Gas Law Explanatory?

    ERIC Educational Resources Information Center

    Woody, Andrea I.

    2013-01-01

    Using the ideal gas law as a comparative example, this essay reviews contemporary research in philosophy of science concerning scientific explanation. It outlines the inferential, causal, unification, and erotetic conceptions of explanation and discusses an alternative project, the functional perspective. In each case, the aim is to highlight…

  9. Generalized summability methods of functions using ideals

    NASA Astrophysics Data System (ADS)

    Savaş, Ekrem

    2015-09-01

    In this paper, we shall make a new approach to two well known summability methods by using ideals and introduce new notions, namely, ℐ-statistical convergence and ℐ-lacunary statistical convergence by taking a nonnegative real-valued Lebesque measurable function in the interval (1, ∞) and mainly investigate their relationship and also make some observations about these classes.

  10. Derivation of the Ideal Gas Law

    ERIC Educational Resources Information Center

    Laugier, Alexander; Garai, Jozsef

    2007-01-01

    Undergraduate and graduate physics and chemistry books usually state that combining the gas laws results in the ideal gas law. Leaving the derivation to the students implies that this should be a simple task, most likely a substitution. Boyle's law, Charles's law, and the Avogadro's principle are given under certain conditions; therefore, direct…

  11. Output performance of idealized microwave power amplifiers

    NASA Astrophysics Data System (ADS)

    Kushner, Lawrence J.

    1989-10-01

    Output power, efficiency, power dissipation and optimum load resistance expressions for idealized microwave class A and class B power amplifiers are derived based on a waveform analysis. The effects of device transconductance variation with bias and circuit harmonic termination are examined.

  12. Developing Ideal Student and Residency Programs.

    ERIC Educational Resources Information Center

    Selvin, Gerald J.

    1993-01-01

    The Veterans Administration (VA) is a primary educator of optometry students, with each college of optometry being affiliated with at least one VA hospital. Ideally, fourth-year optometry students rotate through a specific VA facility for about 12 weeks. Guidelines are designed to provide optimum care in a rich learning environment. (MSE)

  13. 24 electron cluster formulas as the 'molecular' units of ideal metallic glasses

    NASA Astrophysics Data System (ADS)

    Luo, L. J.; Chen, H.; Wang, Y. M.; Qiang, J. B.; Wang, Q.; Dong, C.; Häussler, P.

    2014-08-01

    It is known that ideal metallic glasses fully complying with the Hume-Rothery stabilization mechanism can be expressed by a universal cluster formula of the form [cluster](glue atom)1 or 3. In the present work, it is shown, after a re-examination of the cluster-resonance model, that the number of electrons per unit cluster formula, e/u, is universally 24. The cluster formulas are then the atomic as well as the electronic structural units, mimicking the 'molecular' formulas for chemical substances. The origin of different electron number per atom ratios e/a is related to the total number of atoms Z in unit cluster formula, e/a = 24/Z. The 24 electron formulas are well confirmed in typical binary and ternary bulk metallic glasses.

  14. The ideal subject distance for passport pictures.

    PubMed

    Verhoff, Marcel A; Witzel, Carsten; Kreutz, Kerstin; Ramsthaler, Frank

    2008-07-04

    In an age of global combat against terrorism, the recognition and identification of people on document images is of increasing significance. Experiments and calculations have shown that the camera-to-subject distance - not the focal length of the lens - can have a significant effect on facial proportions. Modern passport pictures should be able to function as a reference image for automatic and manual picture comparisons. This requires a defined subject distance. It is completely unclear which subject distance, in the taking of passport photographs, is ideal for the recognition of the actual person. We show here that the camera-to-subject distance that is perceived as ideal is dependent on the face being photographed, even if the distance of 2m was most frequently preferred. So far the problem of the ideal camera-to-subject distance for faces has only been approached through technical calculations. We have, for the first time, answered this question experimentally with a double-blind experiment. Even if there is apparently no ideal camera-to-subject distance valid for every face, 2m can be proposed as ideal for the taking of passport pictures. The first step would actually be the determination of a camera-to-subject distance for the taking of passport pictures within the standards. From an anthropological point of view it would be interesting to find out which facial features allow the preference of a shorter camera-to-subject distance and which allow the preference of a longer camera-to-subject distance.

  15. Eigenanalysis of Ideal Hall MHD Turbulence

    NASA Astrophysics Data System (ADS)

    Fu, T.; Shebalin, J. V.

    2011-12-01

    Ideal, incompressible, homogeneous, Hall magnetohydrodynamic (HMHD) turbulence may be investigated through a Fourier spectral method. In three-dimensional periodic geometry, the independent Fourier coefficients represent a canonical ensemble described by a Gaussian probability density. The canonical ensemble is based on the conservation of three invariants: total energy, generalized helicity, and magnetic helicity. Generalized helicity in HMHD takes the place of cross helicity in MHD. The invariants determine the modal probability density giving the spectral structure and equilibrium statistics of ideal HMHD, which are compared to known MHD results. New results in absolute equilibrium ensemble theory are derived using a novel approach that involves finding the eigenvalues of a Hermitian covariance matrix for each modal probability density. The associated eigenvectors transform the original phase space variables into eigenvariables through a special unitary transformation. These are the normal modes which facilitate the analysis of ideal HMHD non-linear dynamics. The eigenanalysis predicts that the low wavenumber modes with very small eigenvalues may have mean values that are large compared to their standard deviations, contrary to the ideal ensemble prediction of zero mean values. (Expectation values may also be relatively large at the highest wave numbers, but the addition of even small levels of dissipation removes any relevance this may have for real-world turbulence.) This behavior is non-ergodic over very long times for a numerical simulation and is termed 'broken ergodicity'. For fixed values of the ideal invariants, the effect is seen to be enhanced with increased numerical grid size. Broken ergodicity at low wave number modes gives rise to large-scale, quasi-stationary, coherent structure. Physically, this corresponds to plasma relaxation to force-free states. For real HMHD turbulence with dissipation, broken ergodicity and coherent structure are still

  16. Atomic arias

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2009-01-01

    The American composer John Adams uses opera to dramatize controversial current events. His 1987 work Nixon in China was about the landmark meeting in 1972 between US President Richard Nixon and Chairman Mao Zedong of China; The Death of Klinghoffer (1991) was a musical re-enactment of an incident in 1985 when Palestinian terrorists kidnapped and murdered a wheelchair-bound Jewish tourist on a cruise ship. Adams's latest opera, Doctor Atomic, is also tied to a controversial event: the first atomic-bomb test in Alamogordo, New Mexico, on 16 June 1945. The opera premièred in San Francisco in 2005, had a highly publicized debut at the Metropolitan Opera in New York in 2008, and will have another debut on 25 February - with essentially the same cast - at the English National Opera in London.

  17. Atomic rivals

    SciTech Connect

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  18. Atomic physics

    SciTech Connect

    Livingston, A.E.; Kukla, K.; Cheng, S.

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  19. Atomic Databases

    NASA Astrophysics Data System (ADS)

    Mendoza, Claudio

    2000-10-01

    Atomic and molecular data are required in a variety of fields ranging from the traditional astronomy, atmospherics and fusion research to fast growing technologies such as lasers, lighting, low-temperature plasmas, plasma assisted etching and radiotherapy. In this context, there are some research groups, both theoretical and experimental, scattered round the world that attend to most of this data demand, but the implementation of atomic databases has grown independently out of sheer necessity. In some cases the latter has been associated with the data production process or with data centers involved in data collection and evaluation; but sometimes it has been the result of individual initiatives that have been quite successful. In any case, the development and maintenance of atomic databases call for a number of skills and an entrepreneurial spirit that are not usually associated with most physics researchers. In the present report we present some of the highlights in this area in the past five years and discuss what we think are some of the main issues that have to be addressed.

  20. Interacting Ions in Biophysics: Real is not Ideal

    PubMed Central

    Eisenberg, Bob

    2013-01-01

    Ions in water are important throughout biology, from molecules to organs. Classically, ions in water were treated as ideal noninteracting particles in a perfect gas. Excess free energy of each ion was zero. Mathematics was not available to deal consistently with flows, or interactions with other ions or boundaries. Nonclassical approaches are needed because ions in biological conditions flow and interact. The concentration gradient of one ion can drive the flow of another, even in a bulk solution. A variational multiscale approach is needed to deal with interactions and flow. The recently developed energetic variational approach to dissipative systems allows mathematically consistent treatment of the bio-ions Na+, K+, Ca2+, and Cl− as they interact and flow. Interactions produce large excess free energy that dominate the properties of the high concentration of ions in and near protein active sites, ion channels, and nucleic acids: the number density of ions is often >10 M. Ions in such crowded quarters interact strongly with each other as well as with the surrounding protein. Nonideal behavior found in many experiments has classically been ascribed to allosteric interactions mediated by the protein and its conformation changes. The ion-ion interactions present in crowded solutions—independent of conformation changes of the protein—are likely to change the interpretation of many allosteric phenomena. Computation of all atoms is a popular alternative to the multiscale approach. Such computations involve formidable challenges. Biological systems exist on very different scales from atomic motion. Biological systems exist in ionic mixtures (like extracellular and intracellular solutions), and usually involve flow and trace concentrations of messenger ions (e.g., 10−7 M Ca2+). Energetic variational methods can deal with these characteristic properties of biological systems as we await the maturation and calibration of all-atom simulations of ionic mixtures and

  1. Interacting ions in biophysics: real is not ideal.

    PubMed

    Eisenberg, Bob

    2013-05-07

    Ions in water are important throughout biology, from molecules to organs. Classically, ions in water were treated as ideal noninteracting particles in a perfect gas. Excess free energy of each ion was zero. Mathematics was not available to deal consistently with flows, or interactions with other ions or boundaries. Nonclassical approaches are needed because ions in biological conditions flow and interact. The concentration gradient of one ion can drive the flow of another, even in a bulk solution. A variational multiscale approach is needed to deal with interactions and flow. The recently developed energetic variational approach to dissipative systems allows mathematically consistent treatment of the bio-ions Na(+), K(+), Ca(2+), and Cl(-) as they interact and flow. Interactions produce large excess free energy that dominate the properties of the high concentration of ions in and near protein active sites, ion channels, and nucleic acids: the number density of ions is often >10 M. Ions in such crowded quarters interact strongly with each other as well as with the surrounding protein. Nonideal behavior found in many experiments has classically been ascribed to allosteric interactions mediated by the protein and its conformation changes. The ion-ion interactions present in crowded solutions-independent of conformation changes of the protein-are likely to change the interpretation of many allosteric phenomena. Computation of all atoms is a popular alternative to the multiscale approach. Such computations involve formidable challenges. Biological systems exist on very different scales from atomic motion. Biological systems exist in ionic mixtures (like extracellular and intracellular solutions), and usually involve flow and trace concentrations of messenger ions (e.g., 10(-7) M Ca(2+)). Energetic variational methods can deal with these characteristic properties of biological systems as we await the maturation and calibration of all-atom simulations of ionic mixtures

  2. Absorption imaging of a single atom

    NASA Astrophysics Data System (ADS)

    Streed, Erik W.; Jechow, Andreas; Norton, Benjamin G.; Kielpinski, David

    2012-07-01

    Absorption imaging has played a key role in the advancement of science from van Leeuwenhoek's discovery of red blood cells to modern observations of dust clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first absorption imaging of a single atom isolated in a vacuum. The optical properties of atoms are thoroughly understood, so a single atom is an ideal system for testing the limits of absorption imaging. A single atomic ion was confined in an RF Paul trap and the absorption imaged at near wavelength resolution with a phase Fresnel lens. The observed image contrast of 3.1 (3)% is the maximum theoretically allowed for the imaging resolution of our set-up. The absorption of photons by single atoms is of immediate interest for quantum information processing. Our results also point out new opportunities in imaging of light-sensitive samples both in the optical and X-ray regimes.

  3. Absorption imaging of a single atom.

    PubMed

    Streed, Erik W; Jechow, Andreas; Norton, Benjamin G; Kielpinski, David

    2012-07-03

    Absorption imaging has played a key role in the advancement of science from van Leeuwenhoek's discovery of red blood cells to modern observations of dust clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first absorption imaging of a single atom isolated in a vacuum. The optical properties of atoms are thoroughly understood, so a single atom is an ideal system for testing the limits of absorption imaging. A single atomic ion was confined in an RF Paul trap and the absorption imaged at near wavelength resolution with a phase Fresnel lens. The observed image contrast of 3.1 (3)% is the maximum theoretically allowed for the imaging resolution of our set-up. The absorption of photons by single atoms is of immediate interest for quantum information processing. Our results also point out new opportunities in imaging of light-sensitive samples both in the optical and X-ray regimes.

  4. Polymeric Materials Resistant to Erosion by Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.; Thibeault, Sheila A.

    2004-01-01

    Polymer-matrix composites are ideally suited for space vehicles because of high strength to weight ratios. The principal component of the low earth orbit (LEO) is atomic oxygen. Atomic oxygen causes surface erosion to polymeric materials. Polymer films with an organometallic additive showed greater resistance to atomic oxygen than the pure polymer in laboratory experiments and in the OPM/MIR experiment. In MISSE, the film with the organometallic additive was still intact after the pure film had completely eroded.

  5. National Centre for Radio Astrophysics

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    India's National Centre for Radio Astrophysics (NCRA), located on the Pune University Campus, is part of the TATA INSTITUTE OF FUNDAMENTAL RESEARCH. At Khodad, 80 km from Pune, NCRA has set up the Giant Metrewave Radio Telescope (GMRT), the world's largest telescope operating at meter wavelengths. GMRT consists of 30 fully steerable dishes of 45 m diameter, spread over a 25 km area. Another meter...

  6. Quantized vortices in the ideal bose gas: a physical realization of random polynomials.

    PubMed

    Castin, Yvan; Hadzibabic, Zoran; Stock, Sabine; Dalibard, Jean; Stringari, Sandro

    2006-02-03

    We propose a physical system allowing one to experimentally observe the distribution of the complex zeros of a random polynomial. We consider a degenerate, rotating, quasi-ideal atomic Bose gas prepared in the lowest Landau level. Thermal fluctuations provide the randomness of the bosonic field and of the locations of the vortex cores. These vortices can be mapped to zeros of random polynomials, and observed in the density profile of the gas.

  7. Arsenic-terminated Ge(111): An ideal 1 x 1 surface

    SciTech Connect

    Bringans, R.D.; Uhrberg, R.I.G.; Bachrach, R.Z.; Northrup, J.E.

    1985-07-29

    Arsenic interaction with the Ge(111) surface results in the replacement of the outer Ge layer with an As layer. This system has a 1 x 1 symmetry and the calculated positions of the As atoms are very close to the positions expected from bulk bond lengths. Ge(111):As is thus a model ideal surface and a comparison is made of an experimental and a theoretical determination of its fully occupied surface band.

  8. The Ideal Man and Woman According to University Students

    ERIC Educational Resources Information Center

    Weinstein, Lawrence; Laverghetta, Antonio V.; Peterson, Scott A.

    2009-01-01

    The present study determined if the ideal man has changed over the years and who and what the ideal woman is. We asked students at Cameron University to rate the importance of character traits that define the ideal man and woman. Subjects also provided examples of famous people exemplifying the ideal, good, average, and inferior man and woman. We…

  9. The Ideal Man and Woman According to University Students

    ERIC Educational Resources Information Center

    Weinstein, Lawrence; Laverghetta, Antonio V.; Peterson, Scott A.

    2009-01-01

    The present study determined if the ideal man has changed over the years and who and what the ideal woman is. We asked students at Cameron University to rate the importance of character traits that define the ideal man and woman. Subjects also provided examples of famous people exemplifying the ideal, good, average, and inferior man and woman. We…

  10. Nurse middle managers contributions to patient-centred care: A 'managerial work' analysis.

    PubMed

    Lalleman, Pcb; Smid, Gac; Dikken, J; Lagerwey, M D; Schuurmans, M J

    2017-03-21

    Nurse middle managers are in an ideal position to facilitate patient-centred care. However, their contribution is underexposed in literature due to difficulties to articulate this in practice. This paper explores how nurse middle managers contribute to patient-centred care in hospitals. A combination of time-use analysis and ethnographic work was used to disclose their contribution to patient-centred care at a micro level. Sixteen nurse managers were shadowed for over 560 hours in four hospitals. Some nurse middle managers seldom contribute to patient-centred care. Others are involved in direct patient care, but this does not result in patient-centred practices. At one hospital, the nurse middle managers did contribute to patient-centred care. Here balancing between "organizing work" and "caring work" is seen as a precondition for their patient-centeredness. Other important themes are feedback mechanisms; place matters; with whom to talk and how to frame the issues at stake; and behavioral style. Both "hands-on" and "heads-on" caring work of nurse middle managers enhances their patient-centeredness. This study is the first of its kind to obtain insight in the often difficult to articulate "doings" of nurse middle managers with regard to patient-centred care through combining time-use analysis with ethnographic work.

  11. European Centre for Disease Prevention and Control.

    PubMed

    Evans, Roger

    2014-11-04

    The European Centre for Disease Prevention and Control was set up in 2005 to strengthen Europe's defences against infectious diseases. The centre is an independent agency of the European Union and is based in Stockholm, Sweden.

  12. Group analysis of an ideal plasticity model

    NASA Astrophysics Data System (ADS)

    Lamothe, Vincent

    2012-07-01

    A group analysis of a system describing an ideal plastic flow is made in order to obtain analytical solutions. The complete Lie algebra of point symmetries of this system are given. Two of the infinitesimal generators that span the Lie algebra are original to this paper. A classification into conjugacy classes of all one- and two-dimensional subalgebras is performed. Invariant and partially invariant solutions corresponding to certain conjugacy classes are obtained using the symmetry reduction method. Solutions of algebraic, trigonometric, inverse trigonometric and elliptic type are provided as illustrations and other solutions expressed in terms of one or two arbitrary functions have also been found. For some of these solutions, a physical interpretation allows one to determine the shape of feasible extrusion dies corresponding to these solutions. The corresponding tools could be used to curve rods or slabs, or to shape a ring in an ideal plastic material by an extrusion process.

  13. Structural arrest in an ideal gas.

    PubMed

    van Ketel, Willem; Das, Chinmay; Frenkel, Daan

    2005-04-08

    We report a molecular dynamics study of a simple model system that has the static properties of an ideal gas, yet exhibits nontrivial "glassy" dynamics behavior at high densities. The constituent molecules of this system are constructs of three infinitely thin hard rods of length L, rigidly joined at their midpoints. The crosses have random but fixed orientation. The static properties of this system are those of an ideal gas, and its collision frequency can be computed analytically. For number densities NL(3)/V>1, the single-particle diffusivity goes to zero. As the system is completely structureless, standard mode-coupling theory cannot describe the observed structural arrest. Nevertheless, the system exhibits many dynamical features that appear to be mode-coupling-like. All high-density incoherent intermediate scattering functions collapse onto master curves that depend only on the wave vector.

  14. Modeling of non-ideal aluminized explosives

    NASA Astrophysics Data System (ADS)

    Howard, W. M.; Fried, L. E.; Souers, P. C.

    2000-04-01

    We have implemented a Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions, while other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. Within the context of WK theory, we study the chemical interaction between Al and HMX detonation products in non-ideal explosives. We develop a kinetic rate law for the combustion of Al in a condensed detonation that depends on the pressure and the detonation product gases. We use a Murnaghan form for the equation of state of the solid and liquid Al and Al2O3. We find that we can replicate experimental detonation velocities for HMX/Al composites to within a few percent for a wide range of aluminum content. We discuss the uncertainties in our model and the implications of our results on the modeling of other non-ideal explosives ???

  15. Non-ideal Solution Thermodynamics of Cytoplasm

    PubMed Central

    Ross-Rodriguez, Lisa U.; McGann, Locksley E.

    2012-01-01

    Quantitative description of the non-ideal solution thermodynamics of the cytoplasm of a living mammalian cell is critically necessary in mathematical modeling of cryobiology and desiccation and other fields where the passive osmotic response of a cell plays a role. In the solution thermodynamics osmotic virial equation, the quadratic correction to the linear ideal, dilute solution theory is described by the second osmotic virial coefficient. Herein we report, for the first time, intracellular solution second osmotic virial coefficients for four cell types [TF-1 hematopoietic stem cells, human umbilical vein endothelial cells (HUVEC), porcine hepatocytes, and porcine chondrocytes] and further report second osmotic virial coefficients indistinguishable from zero (for the concentration range studied) for human hepatocytes and mouse oocytes. PMID:23840923

  16. Variational Integrators for Ideal and Reduced Magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Kraus, Michael; Maj, Omar; Tassi, Emanuele; Grasso, Daniela

    2016-10-01

    Ideal and reduced magnetohydrodynamics are simplified sets of magnetohydrodynamics equations with applications to both fusion and astrophysical plasmas, possessing a noncanonical Hamiltonian structure and a number of conserved functionals. We propose a new discretisation strategy for these equations based on a discrete variational principle applied to a formal Lagrangian. Discrete exterior calculus is used for the discretisation of the field variables in order to preserve their geometrical character. The resulting integrators preserve important quantities like the total energy, magnetic helicity and cross helicity exactly (up to machine precision). As these integrators are free of numerical resistivity, the magnetic field line topology is preserved and spurious reconnection is absent in the ideal case. Only when effects of finite electron mass are added, magnetic reconnection takes place. The excellent conservation properties of the methods are exemplified with numerical examples in 2D. We conclude with an outlook towards the treatment of general geometries in 3D and full magnetohydrodynamics.

  17. Kinetic modeling of non-ideal explosives

    SciTech Connect

    Fried, L E; Howard, W M; Souers, P C

    1999-03-01

    We have implemented a Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions, while other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. We model a wide range of ideal and non-ideal composite energetic materials. In addition, we develop an exp-6 equation of state for the product fluids that reproduces a wide range experimental shock Hugoniot and static compression data. For unreacted solids, including solid and liquid Al and Al{sub 2}O{sub 3}, we use a Murnaghan form for the equation of state. We find that we can replicate experimental detonation velocities to within a few per cent for a wide range of explosives, while obtaining good agreement with estimated reaction zone lengths. The detonation velocity as a function of charge radius is also correctly reproduced.

  18. Ideal photon number amplifier and duplicator

    NASA Technical Reports Server (NTRS)

    Dariano, G. M.

    1992-01-01

    The photon number-amplification and number-duplication mechanism are analyzed in the ideal case. The search for unitary evolutions leads to consider also a number-deamplification mechanism, the symmetry between amplification and deamplification being broken by the integer-value nature of the number operator. Both transformations, amplification and duplication, need an auxiliary field which, in the case of amplification, turns out to be amplified in the inverse way. Input-output energy conservation is accounted for using a classical pump or through frequency-conversion of the fields. Ignoring one of the fields is equivalent to considering the amplifier as an open system involving entropy production. The Hamiltonians of the ideal devices are given and compared with those of realistic systems.

  19. Localization in an Idealized Heterogeneous Elastic Sheet

    NASA Astrophysics Data System (ADS)

    Gurmessa, Bekele; Croll, Andrew B.

    2015-03-01

    Localized deformation is ubiquitous in many natural and engineering materials. Often times such deformations are associated to non-homogeneous strain fields in the materials. In this work we demonstrate the response of idealized non-homogenous elastic sheets to uniaxial compression. The idealized/patterned surface layers are created by selective ultraviolet/ozone (UVO) treatment of the top surface of polydimethylsiloxane (PDMS) using TEM grid mask. By controlling the exposure time of the UVO, samples ranging from continuous thin films to sets of isolated small plates were created. We show how local strains vary with location in a patterned sample, leading to a complex localization process Even at low strains. We also see that continuous regions form isotropic undulations upon compression which persist to high strains, well beyond where localization is observed in the patterned regions. Despite the complexity, the localized deformation profile can be adequately described with a simple elastic model when appropriate local boundary conditions are considered.

  20. Preserving idealism in global health promotion.

    PubMed

    Franco-Paredes, Carlos; Zeuli, Julia; Hernández-Ramos, Isabel; Santos-Preciado, Jose I

    2010-12-01

    If the field of global health is to evolve in the second decade of the new millennium, we need to revive the idealistic spirit and by using the lens of health equity work toward improved health status around the world. Morality and empathy are considered by-products of our evolutionary history as a human species. Idealism may be a trait that we may choose to preserve in our modern evolutionary history.

  1. Concepts of Ideal and Nonideal Explosives.

    DTIC Science & Technology

    1981-12-01

    linear equation, and deviations will become important at different radii for each explosive. For example, with XTX - 8003 , extremely small radii are...quantity, most tests of ideality-nonideality refer to it only. However, it is the least sensitive of the detonation parameters. DIAMETER EFFECT The concept...applied to a wide variety of explosives with reasonable success. It appears that the theory is not too sensitive to the assumptions. 2 Equations of State

  2. Note on the ideal frame formulation

    NASA Astrophysics Data System (ADS)

    Lara, Martin

    2017-09-01

    An implementation of the ideal frame formulation of perturbed Keplerian motion is presented which only requires the integration of a differential system of dimension 7, contrary to the 8 variables traditionally integrated with this approach. The new formulation is based on the integration of a scaled version of the Eulerian set of redundant parameters and slightly improves runtime performance with respect to the 8-dimensional case while retaining comparable accuracy.

  3. VH-1: Multidimensional ideal compressible hydrodynamics code

    NASA Astrophysics Data System (ADS)

    Hawley, John; Blondin, John; Lindahl, Greg; Lufkin, Eric

    2012-04-01

    VH-1 is a multidimensional ideal compressible hydrodynamics code written in FORTRAN for use on any computing platform, from desktop workstations to supercomputers. It uses a Lagrangian remap version of the Piecewise Parabolic Method developed by Paul Woodward and Phil Colella in their 1984 paper. VH-1 comes in a variety of versions, from a simple one-dimensional serial variant to a multi-dimensional version scalable to thousands of processors.

  4. The DIY Digital Medical Centre.

    PubMed

    Timmis, James Kenneth; Timmis, Kenneth

    2017-09-01

    Healthcare systems worldwide are confronted with major economic, organizational and logistical challenges. Historic evolution of health care has led to significant healthcare sector fragmentation, resulting in systemic inefficiencies and suboptimal resource exploitation. To attain a sustainable healthcare model, fundamental, system-wide improvements that effectively network, and ensure fulfilment of potential synergies between sectors, and include and facilitate coherent strategic planning and organisation of healthcare infrastructure are needed. Critically, they must be specifically designed to sustainably achieve peak performance within the current policy environment for cost-control, and efficiency and quality improvement for service delivery. We propose creation of a new healthcare cluster, to be embedded in existing healthcare systems. It consists of (i) local 24/7 walk-in virtually autonomous do-it-yourself Digital Medical Centres performing routine diagnosis, monitoring, prevention, treatment and standardized documentation and health outcome assessment/reporting, which are online interfaced with (ii) regional 24/7 eClinician Centres providing on-demand clinical supervision/assistance to Digital Medical Centre patients. Both of these are, in turn, online interfaced with (iii) the National Clinical Informatics Centre, which houses the national patient data centre (cloud) and data analysis units that conduct patient- and population-level, personalized and predictive(-medicine) intervention optimization analyses. The National Clinical Informatics Centre also interfaces with biomedical research and prioritizes and accelerates the translation of new discoveries into clinical practice. The associated Health Policy Innovation and Evaluation Centre rapidly integrates new findings with health policy/regulatory discussions. This new cluster would synergistically link all health system components in a circular format, enable not only access by all arms of the health

  5. Communicating astronomy by the Unizul Science Centre

    NASA Astrophysics Data System (ADS)

    Beesham, A.; Beesham, N.

    2015-03-01

    The University of Zululand, situated along the east coast of KwaZulu-Natal, has a thriving Science Centre (USC) situated in the developing port city of Richards Bay. Over 30 000 learners visit the centre annually, and it consists of an exhibition area, an auditorium, lecture areas and offices. The shows consist of interactive games, science shows, competitions, quizzes and matriculation workshops. Outreach activities take place through a mobile science centre for schools and communities that cannot visit the centre.

  6. Word recognition using ideal word patterns

    NASA Astrophysics Data System (ADS)

    Zhao, Sheila X.; Srihari, Sargur N.

    1994-03-01

    The word shape analysis approach to text recognition is motivated by discoveries in psychological studies of the human reading process. It attempts to describe and compare the shape of the word as a whole object without trying to segment and recognize the individual characters, so it bypasses the errors committed in character segmentation and classification. However, the large number of classes and large variation and distortion expected in all patterns belonging to the same class make it difficult for conventional, accurate, pattern recognition approaches. A word shape analysis approach using ideal word patterns to overcome the difficulty and improve recognition performance is described in this paper. A special word pattern which characterizes a word class is extracted from different sample patterns of the word class and stored in memory. Recognition of a new word pattern is achieved by comparing it with the special pattern of each word class called ideal word pattern. The process of generating the ideal word pattern of each word class is proposed. The algorithm was tested on a set of machine printed gray scale word images which included a wide range of print types and qualities.

  7. Non-Ideal Behavior in Solvent Extraction

    SciTech Connect

    Peter Zalupski

    2011-09-01

    This report presents a summary of the work performed to meet FCR&D level 3 milestone M31SW050801, 'Complete the year-end report summarizing FY11 experimental and modeling activities.' This work was carried out under the auspices of the Non-Ideality in Solvent Extraction Systems FCR&D work package. The report summarizes our initial considerations of potential influences that non-ideal chemistry may impose on computational prediction of outcomes in solvent extraction systems. The report is packaged into three separate test cases where a robustness of the prediction by SXFIT program is under scrutiny. The computational exercises presented here emphasize the importance of accurate representation of both an aqueous and organic mixtures when modeling liquid-liquid distribution systems. Case No.1 demonstrates that non-ideal behavior of HDEHP in aliphatic diluents, such as n-dodecane, interferes with the computation. Cases No.2 and No.3 focus on the chemical complexity of aqueous electrolyte mixtures. Both exercises stress the need for an improved thermodynamic model of an aqueous environment present in the europium distribution experiments. Our efforts for year 2 of this project will focus on the improvements of aqueous and non-aqueous solution models using fundamental physical properties of mixtures acquired experimentally in our laboratories.

  8. A model of the ideal molecular surface

    NASA Astrophysics Data System (ADS)

    Henson, Bryan; Smilowitz, Laura

    2014-03-01

    We utilize two manifestations of the phenomena of the quasiliquid phase on the surface of molecular crystals to formulate a universal thermodynamic theory describing the thickness of the layer as a function of the liquid phase activity. We use direct measurements of the liquid thickness as a function of temperature and measurements of the acceleration of thermal decomposition as a function of temperature approaching the melting point to illustrate the mechanism. We show that given the existence of a liquid phase below the melting point the ideal liquid activity is necessarily a fixed function of the free energies of sublimation and vaporization. We use this activity to create a reduced formula for the liquid thickness generally applicable to the molecular surface. We provide a prediction of the mechanism and kinetics of quasiliquid formation and show that the phase exists as a metastable kinetic steady state. We show that to first order the principle controlling feature of the system is the configurational entropy of the liquid/solid interface, rather than the specifics of the surface potential energy. This is analogous to other bulk colligative phenomena such as ideal gas and solution theories, and is thus an ideal, universal formulation of inherent, thermodynamically driven, surface disorder.

  9. [The ideal of facial beauty: a review].

    PubMed

    Hönn, Mirjam; Göz, Gernot

    2007-01-01

    In this review article we examine the question as to which parameters of facial attraction are amenable to measurement and which tools are available to perform these measurements. The evaluation of facial images, artistic standards, cephalometry, and anthropometry are discussed. Furthermore, we consider how the attractiveness of a face is influenced by symmetry, averageness and distinguishing features such as dental esthetics or gender specific characteristics. There is a shared concept of what constitutes an "ideal" face. Anthropometric methods are preferable to cephalometric methods in determining the "ideal" face's dimensions, since anthropometric methods are valid, three-dimensional, non-invasive, suitable for a great variety of purposes, and easy to implement. Symmetry and averageness play important roles in determining the attractiveness of a face; although distinguishing features make it extraordinarily beautiful. Such features make a female face appear both child like and mature as well as expressive. Women's preferences as to what constitutes a particularly attractive male face are controversial, since female observers are greatly influenced by their menstrual cycles or their environment when responding to male faces. Finally, allowance has to be made for the fact that the ideal of beauty is subject to certain fluctuations in fashion.

  10. Teaching and Learning Centres: Towards Maturation

    ERIC Educational Resources Information Center

    Challis, Di; Holt, Dale; Palmer, Stuart

    2009-01-01

    Approximately 70% of Australian Teaching and Learning Centres have been restructured and/or have undergone leadership changes in the last three years. The volatility of this environment reflects the number of significant challenges faced by Teaching and Learning Centres. In determining what makes Centres successful, the issues that are likely to…

  11. Small Steps towards Student-Centred Learning

    ERIC Educational Resources Information Center

    Jacobs, George M.; Toh-Heng, Hwee Leng

    2013-01-01

    Student centred learning classroom practices are contrasted with those in teacher centred learning classrooms. The discussion focuses on the theoretical underpinnings of the former, and provides nine steps and tips on how to implement student centred learning strategies, with the aim of developing the 21st century skills of self-directed and…

  12. Medical ethics and more: ideal theories, non-ideal theories and conscientious objection.

    PubMed

    Luna, Florencia

    2015-01-01

    Doing 'good medical ethics' requires acknowledgment that it is often practised in non-ideal circumstances! In this article I present the distinction between ideal theory (IT) and non-ideal theory (NIT). I show how IT may not be the best solution to tackle problems in non-ideal contexts. I sketch a NIT framework as a useful tool for bioethics and medical ethics and explain how NITs can contribute to policy design in non-ideal circumstances. Different NITs can coexist and be evaluated vis-à-vis the IT. Additionally, I address what an individual doctor ought to do in this non-ideal context with the view that knowledge of NITs can facilitate the decision-making process. NITs help conceptualise problems faced in the context of non-compliance and scarcity in a better and more realistic way. Deciding which policy is optimal in such contexts may influence physicians' decisions regarding their patients. Thus, this analysis-usually identified only with policy making-may also be relevant to medical ethics. Finally, I recognise that this is merely a first step in an unexplored but fundamental theoretical area and that more work needs to be done. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. Atom Skimmers and Atom Lasers Utilizing Them

    NASA Technical Reports Server (NTRS)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  14. The Modified Embedded Atom Method

    SciTech Connect

    Baskes, M.I.

    1994-08-01

    Recent modifications have been made to generalize the Embedded Atom Method (EAM) to describe bonding in diverse materials. By including angular dependence of the electron density in an empirical way, the Modified Embedded Atom Method (MEAM) has been able to reproduce the basic energetic and structural properties of 45 elements. This method is ideally suited for examining the interfacial behavior of dissimilar materials. This paper explains in detail the derivation of the method, shows how the parameters of the MEAM are determined directly from experiment or first principles calculations, and examines the quality of the reproduction of the database. Materials with fcc, bcc, hcp, and diamond cubic crystal structure are discussed. A few simple examples of the application of the MEAM to surfaces and interfaces are presented. Calculations of pullout of a SiC fiber in a diamond matrix as a function of applied stress show non-uniform deformation of the fiber.

  15. Increased body satisfaction after exposure to thin ideal children's television in young girls showing thin ideal internalisation.

    PubMed

    Anschutz, Doeschka J; Engels, Rutger C M E; Van Strien, Tatjana

    2012-01-01

    This study tested the direct effect of watching thin ideal children's television on body satisfaction in preadolescent girls (6-8 years old). A within-subject design was used in which girls (N = 51) were tested three times. They watched television clips in random order containing either (1) thin ideal animated characters or (2) animated characters with no thin ideal features or (3) 'real' human actors with no thin ideal features. After watching, their state body satisfaction was measured. Girls with higher levels of thin ideal internalisation showed higher body satisfaction after exposure to the thin ideal characters than after exposure to animated or real characters featuring no thin ideal features. No differences on body satisfaction between the exposure conditions were found in girls with lower levels of thin ideal internalisation. The results might suggest that young girls who internalised the thin ideal are inspired by thin ideal characters in children's media.

  16. Atomically resolved graphitic surfaces in air by atomic force microscopy.

    PubMed

    Wastl, Daniel S; Weymouth, Alfred J; Giessibl, Franz J

    2014-05-27

    Imaging at the atomic scale using atomic force microscopy in biocompatible environments is an ongoing challenge. We demonstrate atomic resolution of graphite and hydrogen-intercalated graphene on SiC in air. The main challenges arise from the overall surface cleanliness and the water layers which form on almost all surfaces. To further investigate the influence of the water layers, we compare data taken with a hydrophilic bulk-silicon tip to a hydrophobic bulk-sapphire tip. While atomic resolution can be achieved with both tip materials at moderate interaction forces, there are strong differences in force versus distance spectra which relate to the water layers on the tips and samples. Imaging at very low tip-sample interaction forces results in the observation of large terraces of a naturally occurring stripe structure on the hydrogen-intercalated graphene. This structure has been previously reported on graphitic surfaces that are not covered with disordered adsorbates in ambient conditions (i.e., on graphite and bilayer graphene on SiC, but not on monolayer graphene on SiC). Both these observations indicate that hydrogen-intercalated graphene is close to an ideal graphene sample in ambient environments.

  17. Student-Centred and Teacher-Centred Learning Environments: What Students Think

    ERIC Educational Resources Information Center

    Elen, Jan; Clarebout, Geraldine; Leonard, Rebecca; Lowyck, Joost

    2007-01-01

    This contribution explores the relationship between teacher-centred and student-centred learning environments from a student's perspective. Three different views with respect to this relationship can be retrieved. The "balance" view suggests that the more teacher-centred a learning environment is, the less student-centred it is and vice versa. The…

  18. The DEMETER Science Mission Centre

    NASA Astrophysics Data System (ADS)

    Lagoutte, D.; Brochot, J. Y.; de Carvalho, D.; Elie, F.; Harivelo, F.; Hobara, Y.; Madrias, L.; Parrot, M.; Pinçon, J. L.; Berthelier, J. J.; Peschard, D.; Seran, E.; Gangloff, M.; Sauvaud, J. A.; Lebreton, J. P.; Stverak, S.; Travnicek, P.; Grygorczuk, J.; Slominski, J.; Wronowski, R.; Barbier, S.; Bernard, P.; Gaboriaud, A.; Wallut, J. M.

    2006-04-01

    The DEMETER Scientific Mission Centre (SMC) has been developed and is operated by the Laboratoire de Physique et Chimie de l'Environnement (LPCE). The SMC commands the instruments of the scientific payload, collects and distributes DEMETER data and associated products to the DEMETER international community. The SMC has been designed to maximize scientific return and to reduce development and exploitation costs for the DEMETER project. This paper describes the SMC's data processing system, data server and methods of payload operation, and presents associated hardware and software architectures.

  19. Learning in interactive science centres

    NASA Astrophysics Data System (ADS)

    Beiers, Robin; McRobbie, Cam

    1992-12-01

    The potential of informal sources of science learning to supplement and interact with formal classroom science is receiving increasing recognition and attention in the research literature. In this study, a phenomenographic approach was used to determine changes in levels of understanding of 27 grade 7 primary school children as a result of a visit to an interactive science centre. The results showed that most students did change their levels of understanding of aspects of the concept “sound”. The study also provides information which will be of assistance to teachers on the levels of understanding displayed by students on this concept.

  20. Demonstration of asymmetric electron conduction in pseudosymmetrical photosynthetic reaction centre proteins in an electrical circuit.

    PubMed

    Kamran, Muhammad; Friebe, Vincent M; Delgado, Juan D; Aartsma, Thijs J; Frese, Raoul N; Jones, Michael R

    2015-03-09

    Photosynthetic reaction centres show promise for biomolecular electronics as nanoscale solar-powered batteries and molecular diodes that are amenable to atomic-level re-engineering. In this work the mechanism of electron conduction across the highly tractable Rhodobacter sphaeroides reaction centre is characterized by conductive atomic force microscopy. We find, using engineered proteins of known structure, that only one of the two cofactor wires connecting the positive and negative termini of this reaction centre is capable of conducting unidirectional current under a suitably oriented bias, irrespective of the magnitude of the bias or the applied force at the tunnelling junction. This behaviour, strong functional asymmetry in a largely symmetrical protein-cofactor matrix, recapitulates the strong functional asymmetry characteristic of natural photochemical charge separation, but it is surprising given that the stimulus for electron flow is simply an externally applied bias. Reasons for the electrical resistance displayed by the so-called B-wire of cofactors are explored.

  1. Atomic memory

    NASA Astrophysics Data System (ADS)

    Brewer, R. G.; Hahn, E. L.

    1984-12-01

    The fundamental principles of atomic-memory effects related to the Loschmidt paradox in the second law of thermodynamics are introduced and illustrated with simple analogies, photographs, and diagrams; and the results of RF and laser experiments are summarized. Nuclear-spin echoes in response to RF pulses and the NMR free-induction decay phenomenon are described, and the extension of these concepts to the visible spectrum in laser-frequency-switching and multipulsed-laser experiments is examined with an emphasis on studies of free-induction decay in LaF3 crystals containing Pr impurities (DeVoe and Brewster). The laser-induced phenomena can be applied to studies of intramolecular and intermolecular interactions, and an improved understanding of the RF effects is needed to enhance the performance of medical NMR imaging systems.

  2. Atomic magnetometer

    DOEpatents

    Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  3. The ideal science student and problem solving

    NASA Astrophysics Data System (ADS)

    Sullivan, Florence R.

    2005-09-01

    The purpose of this dissertation was to examine the relationship between students' social mental models of the ideal science student, science epistemological beliefs, problem solving strategies used, and problem solving ability in a robotics environment. Participants were twenty-six academically advanced eleven and twelve year old students attending the Center for Talented Youth summer camp. Survey data was collected from the students including demographic background, views of the ideal science student, and science epistemological beliefs. Students also solved a robotics challenge. This problem solving session was videotaped and students were asked to think aloud as they solved the problem. Two social mental models were identified, a traits-based social mental model and a robust social mental model. A significant association was found between social mental model group and strategy usage. The robust social mental model group is more likely to use domain specific strategies than the traits-based group. Additionally, the robust social mental model group achieved significantly higher scores on their final solution than the traits-based social mental model group. Science epistemological beliefs do not appear to be associated with students' social mental model of the ideal science student. While students with a puzzle-solver view of science were more likely to use domain specific strategies in the planning phase of the problem solving session, there was no significant difference in problem solving ability between this group and students who have a dynamic view of the nature of science knowledge. This difference in strategy usage and problem solving performance may be due to a difference in the students' views of learning and cognition. The robust social mental model group evidenced a situative view of learning and cognition. These students made excellent use of the tools available in the task environment. The traits-based social mental model group displayed an

  4. Statistical Theory of the Ideal MHD Geodynamo

    NASA Technical Reports Server (NTRS)

    Shebalin, J. V.

    2012-01-01

    A statistical theory of geodynamo action is developed, using a mathematical model of the geodynamo as a rotating outer core containing an ideal (i.e., no dissipation), incompressible, turbulent, convecting magnetofluid. On the concentric inner and outer spherical bounding surfaces the normal components of the velocity, magnetic field, vorticity and electric current are zero, as is the temperature fluctuation. This allows the use of a set of Galerkin expansion functions that are common to both velocity and magnetic field, as well as vorticity, current and the temperature fluctuation. The resulting dynamical system, based on the Boussinesq form of the magnetohydrodynamic (MHD) equations, represents MHD turbulence in a spherical domain. These basic equations (minus the temperature equation) and boundary conditions have been used previously in numerical simulations of forced, decaying MHD turbulence inside a sphere [1,2]. Here, the ideal case is studied through statistical analysis and leads to a prediction that an ideal coherent structure will be found in the form of a large-scale quasistationary magnetic field that results from broken ergodicity, an effect that has been previously studied both analytically and numerically for homogeneous MHD turbulence [3,4]. The axial dipole component becomes prominent when there is a relatively large magnetic helicity (proportional to the global correlation of magnetic vector potential and magnetic field) and a stationary, nonzero cross helicity (proportional to the global correlation of velocity and magnetic field). The expected angle of the dipole moment vector with respect to the rotation axis is found to decrease to a minimum as the average cross helicity increases for a fixed value of magnetic helicity and then to increase again when average cross helicity approaches its maximum possible value. Only a relatively small value of cross helicity is needed to produce a dipole moment vector that is aligned at approx.10deg with the

  5. Perceptual centres in speech - an acoustic analysis

    NASA Astrophysics Data System (ADS)

    Scott, Sophie Kerttu

    Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been modelled both in speech and non speech (music) domains. The three aims of this thesis were toatest out current P-centre models to determine which best accounted for the experimental data bto identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centre the final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in which a) speech from different speakers was investigated to determine whether different models could account for variation between speakers b) whether rendering the amplitude time plot of a speech signal affects the P-centre of the signal c) whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by a) manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift b) manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulation c) and whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Filterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of

  6. Hamiltonian description of the ideal fluid

    SciTech Connect

    Morrison, P.J.

    1994-01-01

    Fluid mechanics is examined from a Hamiltonian perspective. The Hamiltonian point of view provides a unifying framework; by understanding the Hamiltonian perspective, one knows in advance (within bounds) what answers to expect and what kinds of procedures can be performed. The material is organized into five lectures, on the following topics: rudiments of few-degree-of-freedom Hamiltonian systems illustrated by passive advection in two-dimensional fluids; functional differentiation, two action principles of mechanics, and the action principle and canonical Hamiltonian description of the ideal fluid; noncanonical Hamiltonian dynamics with examples; tutorial on Lie groups and algebras, reduction-realization, and Clebsch variables; and stability and Hamiltonian systems.

  7. Nonrelativisitic Ideal Gases and Lorentz Violations

    NASA Astrophysics Data System (ADS)

    Colladay, D.; McDonald, P.

    2005-04-01

    We develop statistical mechanics for a nonrelativisitic ideal gas in the presence of Lorentz violating background fields. The analysis is performed using the Standard-Model Extension (SME). We derive the corresponding laws of thermodynamics and find that, to lowest order in Lorentz violation, the scalar thermodynamic variables are corrected by a rotationally invariant combination of the Lorentz terms which can be interpreted in terms of a (frame dependent) effective mass. We find that spin couplings can induce a temperature independent polarization in the gas that is not present in the conventional case.

  8. Broken symmetry in ideal magnetohydrodynamic turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1993-01-01

    A numerical study of the long-time evolution of a number of cases of inviscid, isotropic, incompressible, three-dimensional fluid, and magneto-fluid turbulence has been completed. The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation. The broken symmetry manifests itself as a coherent structure, i.e., a non-zero time-averaged part of the turbulent magnetic field. The coherent structure is observed, in one case, to contain about eighteen percent of the total energy.

  9. Ideal functional outcomes for amputation levels.

    PubMed

    Meier, Robert H; Melton, Danielle

    2014-02-01

    This article provides a generalized overview of amputation classifications and the idealized outcomes for upper and lower amputations at their respective levels. The following levels are discussed: above knee/transfemoral, below knee/transtibial, above elbow/transhumeral, below elbow/transradial, and bilateral for upper and lower extremities. This classification defines a framework for clinicians to share with patients so that they understand the potential for their expected functional outcomes regarding mobility and activities of daily living, both with and without a prosthesis. Moreover, it addresses some of the vocational and avocational needs of the individual regarding amputation. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Ideal pre-conceptual design development

    SciTech Connect

    Gentzlinger, R.; Mendelsohn, S.; Abel, B.

    1993-12-31

    A preconceptual design has been produced for a plasma device to further divertor concepts and validate technology in support of the International Thermonuclear Experimental Reactor program. The ITER Diverter Experiment and Laboratory (IDEAL) design effort is to develop a reliable, maintainable and robust facility for steady-state divertor simulation experiments. The configuration includes a 30 meter vacuum vessel, enclosed within a set of 30 high field superconducting solenoid modules, a resistive quadrupole coil set, a radio-frequency heating system and a complement of diagnostics. It is planned to utilize existing facilities, and off-the-shelf hardware, wherever possible to maximize technological return on investment.

  11. New approach to nonrelativistic ideal magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Kumar, Kuldeep

    2016-07-01

    We provide a novel action principle for nonrelativistic ideal magnetohydrodynamics in the Eulerian scheme exploiting a Clebsch-type parametrisation. Both Lagrangian and Hamiltonian formulations have been considered. Within the Hamiltonian framework, two complementary approaches have been discussed using Dirac's constraint analysis. In one case the Hamiltonian is canonical involving only physical variables but the brackets have a noncanonical structure, while the other retains the canonical structure of brackets by enlarging the phase space. The special case of incompressible magnetohydrodynamics is also considered where, again, both the approaches are discussed in the Hamiltonian framework. The conservation of the stress tensor reveals interesting aspects of the theory.

  12. Coherence Properties of Strongly Interacting Atomic Vapors in Waveguides

    DTIC Science & Technology

    2011-12-31

    predict the outcome. We envision that this technique can be successfully applied for design of quantum mesoscopic devices. Exotic symmetries in cold...Thermalizability (full lecture course), Sum- mer School on "Quantum Many-Body Physics of ultra-Cold Atoms and Molecules" Abdus Salam International Centre for...Physics from Classical to Quantum Low Dimensional Systems", Abdus Salam International Centre for Theoretical Physics, Trieste, Italy, July 6-24, 2009

  13. Atoms and Molecules in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Schmelcher, P.; Cederbaum, L. S.

    Selected topics on atoms and molecules in strong magnetic fields are reviewed. The enormous progress made for the hydrogen atom in a magnetic field and its impact on different areas like, for example, modern semi-classics and dynamics of non-integrable systems as well as laser spectroscopy are outlined. Due to the non-separability of the centre of mass and electronic motion of atoms/molecules in magnetic fields a variety of two-body phenomena can be observed in highly excited systems. Examples are the classical diffusion of the centre of mass and the giant dipole states for crossed fields. For ions energy transfer processes lead to the so-called self-ionisation process. Magnetically induced crossovers for the ground states of atoms are investigated. The increasing complexity of the ground state behaviour of magnetically dressed multi-electron atoms due to changes of the spin polarisation as well as spatial orbitals is demonstrated. For molecules, both fundamental aspects as well as the electronic structure of few-electron diatomics are reviewed.

  14. Atomic environments in iron meteorites using EXAFS

    NASA Technical Reports Server (NTRS)

    Cressey, G.; Dent, A. J.; Dobson, B.; Evans, A.; Greaves, G. N.; Henderson, C. M. B.; Hutchison, R.; Jenkins, R. N.; Thompson, S. P.; Zhu, R.

    1989-01-01

    Extended x ray absorption fine structure (EXAFS) is observed as a modulation on the high energy side of an x ray absorption edge. It occurs when the photo-ejected electron wave is scattered by neighboring atoms in a solid, and interference occurs between the outgoing and scattered waves. The result is that the absorption spectrum carries a signature that is characteristic of the identity and disposition of scattering atoms around the absorbing atom. Therefore, it may be shown that the Fourier transform of the normalized EXAFS can provide detailed information about the immediate environment of specific atoms in a solid and is ideally suited to the study of cosmic dusts. A study of cosmic dust was initiated using EXAFS and other techniques. The simplest type of cosmic material, namely iron meteorites, was investigated.

  15. Ideal relaxation of the Hopf fibration

    NASA Astrophysics Data System (ADS)

    Smiet, Christopher Berg; Candelaresi, Simon; Bouwmeester, Dirk

    2017-07-01

    Ideal magnetohydrodynamics relaxation is the topology-conserving reconfiguration of a magnetic field into a lower energy state where the net force is zero. This is achieved by modeling the plasma as perfectly conducting viscous fluid. It is an important tool for investigating plasma equilibria and is often used to study the magnetic configurations in fusion devices and astrophysical plasmas. We study the equilibrium reached by a localized magnetic field through the topology conserving relaxation of a magnetic field based on the Hopf fibration in which magnetic field lines are closed circles that are all linked with one another. Magnetic fields with this topology have recently been shown to occur in non-ideal numerical simulations. Our results show that any localized field can only attain equilibrium if there is a finite external pressure, and that for such a field a Taylor state is unattainable. We find an equilibrium plasma configuration that is characterized by a lowered pressure in a toroidal region, with field lines lying on surfaces of constant pressure. Therefore, the field is in a Grad-Shafranov equilibrium. Localized helical magnetic fields are found when plasma is ejected from astrophysical bodies and subsequently relaxes against the background plasma, as well as on earth in plasmoids generated by, e.g., a Marshall gun. This work shows under which conditions an equilibrium can be reached and identifies a toroidal depression as the characteristic feature of such a configuration.

  16. Nonlinear electrophoresis of ideally polarizable particles

    NASA Astrophysics Data System (ADS)

    Figliuzzi, Bruno; Chan, Wai Hong Ronald; Buie, Cullen R.

    2013-11-01

    We focus in this presentation on the nonlinear electrophoresis of ideally polarizable particles. At high applied voltages, significant ionic exchanges occur between the EDL which surrounders the particle and the bulk solution. In this situation, the velocity field, the electric potential and the ionic concentration at the immediate vicinity of the particle are described by a complicated set of coupled nonlinear partial differential equations. These equations are classically considered in the limit of a weak applied field, which enables further analytical progress (Khair and Squires, Phys. Fluids, 2010). However, in the general case, the equation governing the electrophoretic motion of the particle must be solved numerically. In this study, we rely on a numerical approach to determine the electric potential, ionic concentration and velocity field in the bulk solution surrounding the particle. The numerical simulations use a pseudo-spectral which was used successfully by Chu and Bazant to determine the electric potential and the ionic concentration around an ideally polarizable metallic sphere (Physical Review E, 2006). Our numerical model also incorporates the steric model developed by Kilic et al. in 2007 to account for crowding effects in the electric double layer.

  17. What constitutes an ideal dental restorative material?

    PubMed

    Rekow, E D; Bayne, S C; Carvalho, R M; Steele, J G

    2013-11-01

    Intense environmental concerns recently have prompted dentistry to evaluate the performance and environmental impact of existing restoration materials. Doing so entices us to explore the 'what if?' innovation in materials science to create more ideal restorative materials. Articulating a specification for our design and evaluation methods is proving to be more complicated than originally anticipated. Challenges exist not only in specifying how the material should be manipulated and perform clinically but also in understanding and incorporating implications of the skill of the operator placing the restoration, economic considerations, expectations patients have for their investment, cost-effectiveness, influences of the health care system on how and for whom restorations are to be placed, and global challenges that limit the types of materials available in different areas of the world. The quandary is to find ways to actively engage multiple stakeholders to agree on priorities and future actions to focus future directions on the creation of more ideal restorative materials that can be available throughout the world.

  18. Modeling of Non-Ideal Aluminized Detonations

    NASA Astrophysics Data System (ADS)

    Howard, W. Michael; Fried, Laurence E.; Souers, P. Clark

    1999-06-01

    We have implemented a Wood-Kirkwood (WK) kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions, while other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. Within the context of WK theory, we study the chemical interaction between Al and HMX detonation products in non-ideal explosives. We develop a kinetic rate law for the burning of Al in condensed detonation that depends on the surface properties of the Al grains and the detonation product gases. Moreover, we use an exp-6 equation of state for the product fluids that reproduces a wide range experimental shock hugoniot and static compression data. We use a Murnaghan form for the equation of state of the solid and liquid Al and Al_2O_3. We find that we can replicate experimental detonation velocities to within a few per cent for a wide range of aluminum content. We discuss the uncertainties in our model and the implications of our results on the modeling of other non-ideal explosives. This work was performed under the auspices of the U. S. Department of Energy under Contract No. W-7405-ENG-48.

  19. The Statistical Mechanics of Ideal Homogeneous Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2002-01-01

    Plasmas, such as those found in the space environment or in plasma confinement devices, are often modeled as electrically conducting fluids. When fluids and plasmas are energetically stirred, regions of highly nonlinear, chaotic behavior known as turbulence arise. Understanding the fundamental nature of turbulence is a long-standing theoretical challenge. The present work describes a statistical theory concerning a certain class of nonlinear, finite dimensional, dynamical models of turbulence. These models arise when the partial differential equations describing incompressible, ideal (i.e., nondissipative) homogeneous fluid and magnetofluid (i.e., plasma) turbulence are Fourier transformed into a very large set of ordinary differential equations. These equations define a divergenceless flow in a high-dimensional phase space, which allows for the existence of a Liouville theorem, guaranteeing a distribution function based on constants of the motion (integral invariants). The novelty of these particular dynamical systems is that there are integral invariants other than the energy, and that some of these invariants behave like pseudoscalars under two of the discrete symmetry transformations of physics, parity, and charge conjugation. In this work the 'rugged invariants' of ideal homogeneous turbulence are shown to be the only significant scalar and pseudoscalar invariants. The discovery that pseudoscalar invariants cause symmetries of the original equations to be dynamically broken and induce a nonergodic structure on the associated phase space is the primary result presented here. Applicability of this result to dissipative turbulence is also discussed.

  20. Global invariants in ideal magnetohydrodynamic turbulence

    SciTech Connect

    Shebalin, John V.

    2013-10-15

    Magnetohydrodynamic (MHD) turbulence is an important though incompletely understood factor affecting the dynamics of many astrophysical, geophysical, and technological plasmas. As an approximation, viscosity and resistivity may be ignored, and ideal MHD turbulence may be investigated by statistical methods. Incompressibility is also assumed and finite Fourier series are used to represent the turbulent velocity and magnetic field. The resulting model dynamical system consists of a set of independent Fourier coefficients that form a canonical ensemble described by a Gaussian probability density function (PDF). This PDF is similar in form to that of Boltzmann, except that its argument may contain not just the energy multiplied by an inverse temperature, but also two other invariant integrals, the cross helicity and magnetic helicity, each multiplied by its own inverse temperature. However, the cross and magnetic helicities, as usually defined, are not invariant in the presence of overall rotation or a mean magnetic field, respectively. Although the generalized form of the magnetic helicity is known, a generalized cross helicity may also be found, by adding terms that are linear in the mean magnetic field and angular rotation vectors, respectively. These general forms are invariant even in the presence of overall rotation and a mean magnetic field. We derive these general forms, explore their properties, examine how they extend the statistical theory of ideal MHD turbulence, and discuss how our results may be affected by dissipation and forcing.

  1. Simple Waves in Ideal Radiation Hydrodynamics

    SciTech Connect

    Johnson, B M

    2008-09-03

    In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure and index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The general approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.

  2. Global invariants in ideal magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Shebalin, John V.

    2013-10-01

    Magnetohydrodynamic (MHD) turbulence is an important though incompletely understood factor affecting the dynamics of many astrophysical, geophysical, and technological plasmas. As an approximation, viscosity and resistivity may be ignored, and ideal MHD turbulence may be investigated by statistical methods. Incompressibility is also assumed and finite Fourier series are used to represent the turbulent velocity and magnetic field. The resulting model dynamical system consists of a set of independent Fourier coefficients that form a canonical ensemble described by a Gaussian probability density function (PDF). This PDF is similar in form to that of Boltzmann, except that its argument may contain not just the energy multiplied by an inverse temperature, but also two other invariant integrals, the cross helicity and magnetic helicity, each multiplied by its own inverse temperature. However, the cross and magnetic helicities, as usually defined, are not invariant in the presence of overall rotation or a mean magnetic field, respectively. Although the generalized form of the magnetic helicity is known, a generalized cross helicity may also be found, by adding terms that are linear in the mean magnetic field and angular rotation vectors, respectively. These general forms are invariant even in the presence of overall rotation and a mean magnetic field. We derive these general forms, explore their properties, examine how they extend the statistical theory of ideal MHD turbulence, and discuss how our results may be affected by dissipation and forcing.

  3. Modeling of non-ideal aluminized explosives

    SciTech Connect

    Fried, L E; Howard, W M; Souers, P C

    1999-06-01

    We have implemented a Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions, while other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. Within the context of WK theory, we study the chemical interaction between Al and HMX detonation products in non-ideal explosives. We develop a kinetic rate law for the combustion of Al in a condensed detonation that depends on the pressure and the detonation product gases. We use a Murnaghan form for the equation of state of the solid and liquid Al and Al{sub 2}O{sub 3}. We find that we can replicate experimental detonation velocities for HMX/Al composites to within a few percent for a wide range of aluminum content. We discuss the uncertainties in our model and the implications of our results on the modeling of other non-ideal explosives.

  4. Developing antitussives: the ideal clinical trial.

    PubMed

    Birring, Surinder S

    2009-04-01

    Antitussive drugs are amongst the most widely used medications worldwide; however no new class of drugs have been introduced into the market for many years. Trials showing patient benefit are scarce and have been hampered by the lack of objective and validated outcome measures. Recent improvements in the assessment of cough will facilitate better trials and aid the development of antitussive drugs. When conducting a trial, patient selection is of paramount importance. Patients with unexplained chronic cough and sub-acute cough following upper respiratory tract infection are ideal because they represent an unmet clinical need and an untapped market for pharmaceutical companies. Patients with asthma and chronic obstructive pulmonary disease are less suitable since cough suppression is not always desirable and the findings of trials may not be generalisable to all patients with cough. Randomized, placebo-controlled, double-blind clinical trials are obviously the gold standard. The choice of placebo, whether inert or active, depends on the incidence and severity of drug side-effects. The primary outcome measure should be objective and cough monitors are the ideal tool. Subjective outcome measures should be used to assess symptoms and health related quality of life. Properly conducted clinical trials are an opportunity to evaluate the benefits of currently available therapies and aid advances in the antitussive drug market.

  5. Secondary Eyewalls in Idealized HWRF Simulations

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Abarca, S.; Mehra, A.; Tallapragada, V.

    2016-12-01

    The operational Hurricane Weather Research and Forecasting Model (HWRF) is one of the world's best performing hurricane forecast guidance models. The most recent version H216 (with the 2016 year upgrade) is now able to consistently generate secondary eyewalls in its operational setting. Previous versions of HWRF, just like every other state of the art mesoscale model, rarely generated such phenomenon. With multiple recent enhancements in model physics, it is important to understand the effect, if any, of these advancements which can be attributed to allow generation (or lack thereof) of these secondary eyewalls. To shed some light on the role of the physics in secondary eyewall formation in HWRF, we investigate secondary eyewall structures in idealized HWRF simulations. The idealized model configuration includes constant sea surface temperature and absence of any large-scale environmental flow. We identify a significant sensitivity to the boundary layer parameterization and explain how such parameterization is impacting the quality of convective cores outside the primary eyewall that constitute the secondary eyewalls. We also present results from the operational version of the model as supporting evidence of our findings.

  6. Optimal forager against ideal free distributed prey.

    PubMed

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior.

  7. An ideal sealed source life-cycle

    SciTech Connect

    Tompkins, Joseph Andrew

    2009-01-01

    we have today. This regulation created a new regulatory framework seen as promising at the time. However, now they recognize that, despite the good intentions, the NIJWP/85 has not solved any source disposition problems. The answer to these sealed source disposition problems is to adopt a philosophy to correct these regulatory issues, determine an interim solution, execute that solution until there is a minimal backlog of sources to deal with, and then let the mechanisms they have created solve this problem into the foreseeable future. The primary philosophical tenet of the ideal sealed source life cycle follows. You do not allow the creation (or importation) of any source whose use cannot be justified, which cannot be affordably shipped, or that does not have a well-delinated and affordable disposition pathway. The path forward dictates that we fix the problem by embracing the Ideal Source Life cycle. In figure 1, we can see some of the elements of the ideal source life cycle. The life cycle is broken down into four portions, manufacture, use, consolidation, and disposition. These four arbitrary elements allow them to focus on the ideal life cycle phases that every source should go through between manufacture and final disposition. As we examine the various phases of the sealed source life cycle, they pick specific examples and explore the adoption of the ideal life cycle model.

  8. Multiplicity of atomic reconfigurations in an electrochemical Pb single-atom transistor

    NASA Astrophysics Data System (ADS)

    Xie, F.-Q.; Lin, X.-H.; Gross, A.; Evers, F.; Pauly, F.; Schimmel, Th.

    2017-05-01

    One focus of nanoelectronics research is to exploit the physical limits in size and energy efficiency. Here, we demonstrate a device in the form of a fully metallic atomic-scale transistor based on a lead (Pb) single-atom quantum point contact. The atomic configuration of the point contact determines the conductance of the Pb atomic-scale transistor. The conductance multiplicity of the Pb single-atom transistor has been confirmed by performing switching between an electrically nonconducting "off-state" and conducting "on-states" at 1 G0( G0=2 e2/h , where e is the electron charge, and h Planck's constant), 2.0 G0, 3.0 G0, 1.5 G0, 2.4 G0, 2.7 G0, 2.8 G0, and 5.4 G0, respectively. Our density-functional calculations for various ideal Pb single-atom contacts explain the atomic-configuration-related conductance multiplicity of the Pb single-atom transistor. The performance of the Pb single-atom transistors indicates that both the signatures of atomic valence and conductance quantization play roles in electron transport and bistable reconfiguration. The bistable reconfiguration of the electrode tips is an underlying mechanism in the switching of the Pb atomic-scale transistors. The absolute value of the electrochemical potential applied to the gate electrode is less than 30 mV. This merit suggests Pb [besides silver (Ag)] atomic-scale transistors as potential candidates for the development of electronic circuits with low power consumption. The dimension of the switching unit in the Pb single-atom transistor is in the range of 1 nm, which is much smaller than the projected scaling limit of the gate lengths in silicon transistors (5 nm). Therefore, the metallic single-atom transistors may provide perspectives for electronic applications beyond silicon.

  9. Ideal Spintronics in Molecule-Based Novel Organometallic Nanowires.

    PubMed

    Sun, Qilong; Dai, Ying; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao

    2015-08-04

    With the purpose of searching for new intriguing nanomaterial for spintronics, a series of novel metalloporphyrin nanowires (M-PPNW, M = Cr, Mn, Fe, Co, Ni, Cu and Zn) and hybrid nanowires fabricated by metalloporphyrin and metal-phthalocyanine (M-PCNW) are systematically investigated by means of first-principles calculations. Our results indicate that the transition metal atoms (TMs) embedded in the frameworks distribute regularly and separately, without any trend to form clusters, thus leading to the ideally ordered spin distribution. Except for the cases embedded with Ni and Zn, the others are spin-polarized. Remarkably, the Mn-PPNW, Mn-PCNW, MnCu-PPNW, MnCr-PCNW, and MnCu-PCNW frameworks all favor the long-ranged ferromagnetic spin ordering and display half-metallic nature, which are of greatest interest and importance for electronics and spintronics. The predicted Curie temperature for the Mn-PCNW is about 150 K. In addition, it is found that the discrepancy in magnetic coupling for these materials is related to the competition mechanisms of through-bond and through-space exchange interactions. In the present work, we propose not only two novel sets of 1D frameworks with appealing magnetic properties, but also a new strategy in obtaining the half-metallic materials by the combination of different neighboring TMs.

  10. Ideal Spintronics in Molecule-Based Novel Organometallic Nanowires

    PubMed Central

    Sun, Qilong; Dai, Ying; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao

    2015-01-01

    With the purpose of searching for new intriguing nanomaterial for spintronics, a series of novel metalloporphyrin nanowires (M-PPNW, M = Cr, Mn, Fe, Co, Ni, Cu and Zn) and hybrid nanowires fabricated by metalloporphyrin and metal-phthalocyanine (M-PCNW) are systematically investigated by means of first-principles calculations. Our results indicate that the transition metal atoms (TMs) embedded in the frameworks distribute regularly and separately, without any trend to form clusters, thus leading to the ideally ordered spin distribution. Except for the cases embedded with Ni and Zn, the others are spin-polarized. Remarkably, the Mn-PPNW, Mn-PCNW, MnCu-PPNW, MnCr-PCNW, and MnCu-PCNW frameworks all favor the long-ranged ferromagnetic spin ordering and display half-metallic nature, which are of greatest interest and importance for electronics and spintronics. The predicted Curie temperature for the Mn-PCNW is about 150 K. In addition, it is found that the discrepancy in magnetic coupling for these materials is related to the competition mechanisms of through-bond and through-space exchange interactions. In the present work, we propose not only two novel sets of 1D frameworks with appealing magnetic properties, but also a new strategy in obtaining the half-metallic materials by the combination of different neighboring TMs. PMID:26239021

  11. Ideal n-body correlations with massive particles

    NASA Astrophysics Data System (ADS)

    Dall, R. G.; Manning, A. G.; Hodgman, S. S.; Rugway, Wu; Kheruntsyan, K. V.; Truscott, A. G.

    2013-06-01

    In 1963 Glauber introduced the modern theory of quantum coherence, which extended the concept of first-order (one-body) correlations, describing phase coherence of classical waves, to include higher-order (n-body) quantum correlations characterizing the interference of multiple particles. Whereas the quantum coherence of photons is a mature cornerstone of quantum optics, the quantum coherence properties of massive particles remain largely unexplored. To investigate these properties, here we use a uniquely correlated source of atoms that allows us to observe n-body correlations up to the sixth-order at the ideal theoretical limit (n!). Our measurements constitute a direct demonstration of the validity of one of the most widely used theorems in quantum many-body theory--Wick's theorem--for a thermal ensemble of massive particles. Measurements involving n-body correlations may play an important role in the understanding of thermalization of isolated quantum systems and the thermodynamics of exotic many-body systems, such as Efimov trimers.

  12. Ideal Spintronics in Molecule-Based Novel Organometallic Nanowires

    NASA Astrophysics Data System (ADS)

    Sun, Qilong; Dai, Ying; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao

    2015-08-01

    With the purpose of searching for new intriguing nanomaterial for spintronics, a series of novel metalloporphyrin nanowires (M-PPNW, M = Cr, Mn, Fe, Co, Ni, Cu and Zn) and hybrid nanowires fabricated by metalloporphyrin and metal-phthalocyanine (M-PCNW) are systematically investigated by means of first-principles calculations. Our results indicate that the transition metal atoms (TMs) embedded in the frameworks distribute regularly and separately, without any trend to form clusters, thus leading to the ideally ordered spin distribution. Except for the cases embedded with Ni and Zn, the others are spin-polarized. Remarkably, the Mn-PPNW, Mn-PCNW, MnCu-PPNW, MnCr-PCNW, and MnCu-PCNW frameworks all favor the long-ranged ferromagnetic spin ordering and display half-metallic nature, which are of greatest interest and importance for electronics and spintronics. The predicted Curie temperature for the Mn-PCNW is about 150 K. In addition, it is found that the discrepancy in magnetic coupling for these materials is related to the competition mechanisms of through-bond and through-space exchange interactions. In the present work, we propose not only two novel sets of 1D frameworks with appealing magnetic properties, but also a new strategy in obtaining the half-metallic materials by the combination of different neighboring TMs.

  13. Nuclear Science Centre, New Delhi

    SciTech Connect

    Mehta, G.; Potukuchi, P.; Roy, A.

    1995-08-01

    Argonne is collaborating with the Nuclear Science Centre (NSC), New Delhi, to develop a new type of superconducting accelerating structure for low-velocity heavy ions. A copper model has been evaluated and tests on the niobium prototype are currently in progress. Some technical details of this project are described in the Superconducting Linac Development section of this report. All funding for the prototype has come from the NSC, and they have also stationed two staff members at ATLAS for the past two years to gain experience and work on this project. Additional NSC personnel visited ATLAS for extended periods during 1994 for electronics and cryogenics experience and training. Two NSC staff members are scheduled to spend several months at ANL during 1995 to continue tests and developments of the prototype resonators and to initiate fabrication of the production models for their linac project.

  14. A serial qualitative interview study of infant feeding experiences: idealism meets realism.

    PubMed

    Hoddinott, Pat; Craig, Leone C A; Britten, Jane; McInnes, Rhona M

    2012-01-01

    To investigate the infant feeding experiences of women and their significant others from pregnancy until 6 months after birth to establish what would make a difference. Qualitative serial interview study. Two health boards in Scotland. 72 of 541 invited pregnant women volunteered. 220 interviews approximately every 4 weeks with 36 women, 26 partners, eight maternal mothers, one sister and two health professionals took place. The overarching theme was a clash between overt or covert infant feeding idealism and the reality experienced. This is manifest as pivotal points where families perceive that the only solution that will restore family well-being is to stop breast feeding or introduce solids. Immediate family well-being is the overriding goal rather than theoretical longer term health benefits. Feeding education is perceived as unrealistic, overly technical and rules based which can undermine women's confidence. Unanimously families would prefer the balance to shift away from antenatal theory towards more help immediately after birth and at 3-4 months when solids are being considered. Family-orientated interactive discussions are valued above breastfeeding-centred checklist style encounters. Adopting idealistic global policy goals like exclusive breast feeding until 6 months as individual goals for women is unhelpful. More achievable incremental goals are recommended. Using a proactive family-centred narrative approach to feeding care might enable pivotal points to be anticipated and resolved. More attention to the diverse values, meanings and emotions around infant feeding within families could help to reconcile health ideals with reality.

  15. "Bohr's Atomic Model."

    ERIC Educational Resources Information Center

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  16. "Bohr's Atomic Model."

    ERIC Educational Resources Information Center

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  17. The atomic orbitals of the topological atom.

    PubMed

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-07

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  18. Bangalore looks to new interdisciplinary science centre

    NASA Astrophysics Data System (ADS)

    Ramachandran, Ramaseshan

    2008-09-01

    A new centre to boost interdisciplinary research in India is being established in Bangalore - India's IT and software capital. The International Centre for Theoretical Sciences (ICTS) will be led by Spenta Wadia, a theoretical physicist from the Tata Institute of Fundamental Research (TIFR) in Mumbai, which is setting up the new centre. He expects construction of the ICTS, the first of its kind in India, to start by November 2009.

  19. The Ideal of Conversation in the Study of Mass Media.

    ERIC Educational Resources Information Center

    Schudson, Michael

    1978-01-01

    Examines the "ideal of conversation," and demonstrates that most actual conversation rarely achieves the "ideal." Argues that the rise of mass media is responsible for making ideal conversation more realizable, however, by making talk between men and women, and adults and children, more egalitarian and spontaneous. (PD)

  20. Moral Identity as Moral Ideal Self: Links to Adolescent Outcomes

    ERIC Educational Resources Information Center

    Hardy, Sam A.; Walker, Lawrence J.; Olsen, Joseph A.; Woodbury, Ryan D.; Hickman, Jacob R.

    2014-01-01

    The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes.…

  1. Why Education in Public Schools Should Include Religious Ideals

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.; Merry, Michael S.

    2009-01-01

    This article aims to open a new line of debate about religion in public schools by focusing on religious ideals. The article begins with an elucidation of the concept "religious ideals" and an explanation of the notion of reasonable pluralism, in order to be able to explore the dangers and positive contributions of religious ideals and their…

  2. Promoting Spiritual Ideals through Design Thinking in Public Schools

    ERIC Educational Resources Information Center

    Tan, Charlene; Wong, Yew-Leong

    2012-01-01

    Against a backdrop of the debates on religious education in public or state schools, we argue for the introduction of "spiritual ideals" into the public school curriculum. We distinguish our notion of spiritual ideals from "religious ideals" as conceptualised by De Ruyter and Merry. While we agree with De Ruyter and Merry that…

  3. Ideals of ITE Students at the University of Glasgow

    ERIC Educational Resources Information Center

    de Ruyter, Doret J.; Conroy, James C.; Lappin, Mary; McKinney, Stephen

    2003-01-01

    Analysis of a questionnaire completed by initial teacher education (ITE) students at the University of Glasgow shows a clear divergence between their personal and professional ideals. The students define their own ideals predominantly in terms of situations, like being married, having children or being happy. Their professional ideals, which…

  4. Moral Identity as Moral Ideal Self: Links to Adolescent Outcomes

    ERIC Educational Resources Information Center

    Hardy, Sam A.; Walker, Lawrence J.; Olsen, Joseph A.; Woodbury, Ryan D.; Hickman, Jacob R.

    2014-01-01

    The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes.…

  5. Promoting Spiritual Ideals through Design Thinking in Public Schools

    ERIC Educational Resources Information Center

    Tan, Charlene; Wong, Yew-Leong

    2012-01-01

    Against a backdrop of the debates on religious education in public or state schools, we argue for the introduction of "spiritual ideals" into the public school curriculum. We distinguish our notion of spiritual ideals from "religious ideals" as conceptualised by De Ruyter and Merry. While we agree with De Ruyter and Merry that…

  6. Engaging distortions: are we idealizing marriage?

    PubMed

    Bonds-Raacke, J M; Bearden, E S; Carriere, N J; Anderson, E M; Nicks, S D

    2001-03-01

    The present study was an investigation of the premarital status of engagement in terms of relationship satisfaction and marital expectations using the Evaluation and Nurturing Relationship Issues, Communication and Happiness (ENRICH) Marital Satisfaction Scale (EMS) and its two subscales of Idealistic Distortion (ID) and Marital Satisfaction (MS) (D. G. Fournier, D. H. Olson, & J. M. Druckman, 1983). There were 104 students (23 men and 81 women), of which 15 were married, 19 were engaged, and 70 had extended dating relationships. On average, participants had been in the relationship for 3.8 years, and the mean age was 22 years. Results demonstrated that individuals engaged to be married had significantly higher idealistic distortion scores (M = 86.89) than did either married individuals (M = 56.67) or those in extended dating relationships (M = 61.19). Finally, a negative relation was found between length of relationships and marital satisfaction subscores. Results are discussed in light of factors contributing to such idealized thinking.

  7. Neem (Azadirachta indica): towards the ideal insecticide?

    PubMed

    Benelli, Giovanni; Canale, Angelo; Toniolo, Chiara; Higuchi, Akon; Murugan, Kadarkarai; Pavela, Roman; Nicoletti, Marcello

    2017-02-01

    Pesticide resistance is going to change rapidly our antibiotics and insecticides arsenal. In this scenario, plant-derived natural products are considered valuable candidates to reverse this negative trend. Growing research attention is focused on neem (Azadirachta indica, Meliaceae), exploring the utility of its products as insecticides and antibiotics. In this review, we summarised the knowledge on neem oil and neem cake by-products in arthropod pest control, with special reference to mosquito vectors of public health importance. To the best of our knowledge, neem-borne products currently showed effective and eco-friendly features, including little non-target effects, multiple mechanisms of action, low cost, easy production in countries with limited industrial facilities. In particular, the potentiality of neem cake as ideal and affordable source of mosquitocidal compounds in anopheline and aedine control programmes is outlined. Overall, we propose the employ of neem-based products as an advantageous alternative to build newer and safer arthropod control tools.

  8. Review of Idealized Aircraft Wake Vortex Models

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.; Duparcmeur, Fanny M. Limon; Jacob, Don

    2014-01-01

    Properties of three aircraft wake vortex models, Lamb-Oseen, Burnham-Hallock, and Proctor are reviewed. These idealized models are often used to initialize the aircraft wake vortex pair in large eddy simulations and in wake encounter hazard models, as well as to define matched filters for processing lidar observations of aircraft wake vortices. Basic parameters for each vortex model, such as peak tangential velocity and circulation strength as a function of vortex core radius size, are examined. The models are also compared using different vortex characterizations, such as the vorticity magnitude. Results of Euler and large eddy simulations are presented. The application of vortex models in the postprocessing of lidar observations is discussed.

  9. Ideal magnetohydrodynamic interchanges in low density plasmas

    SciTech Connect

    Huang Yimin; Goel, Deepak; Hassam, A.B.

    2005-03-01

    The ideal magnetohydrodynamic equations are usually derived under the assumption V{sub A}<

  10. Positron kinetics in an idealized PET environment

    NASA Astrophysics Data System (ADS)

    Robson, R. E.; Brunger, M. J.; Buckman, S. J.; Garcia, G.; Petrović, Z. Lj.; White, R. D.

    2015-08-01

    The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.

  11. Broken Ergodicity in Ideal, Homogeneous, Incompressible Turbulence

    NASA Technical Reports Server (NTRS)

    Morin, Lee; Shebalin, John; Fu, Terry; Nguyen, Phu; Shum, Victor

    2010-01-01

    We discuss the statistical mechanics of numerical models of ideal homogeneous, incompressible turbulence and their relevance for dissipative fluids and magnetofluids. These numerical models are based on Fourier series and the relevant statistical theory predicts that Fourier coefficients of fluid velocity and magnetic fields (if present) are zero-mean random variables. However, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation. We explain this phenomena in terms of broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We review the theoretical basis of broken ergodicity, apply it to 2-D and 3-D fluid and magnetohydrodynamic simulations of homogeneous turbulence, and show new results from simulations using GPU (graphical processing unit) computers.

  12. IDEAL Symposium on the East African Lakes

    NASA Astrophysics Data System (ADS)

    Johnson, T. C.; Kelts, K.; Lehman, J. T.; Wuest, A.

    A vast array of interdisciplinary problems presented by the African Great Lakes were highlighted at the International Symposium on the Limnology, Climatology and Paleoclimatology of the East African Lakes, organized by the International Decade for the East African Lakes (IDEAL) February 17-21 in Jinja, Uganda. Approximately 125 scientists attended from North America, Europe, Africa, and New Zealand. Jinja is located on the northern shore of Lake Victoria at the head-waters of the Nile and is the site of the host institution for the symposium, the Uganda Freshwater Fisheries Research Organization (UFFRO). The conveners of the symposium were Tom Johnson of Duke University, George Kitaka of UNESCO-ROSTA, and Eric Odada of the University of Nairobi.

  13. IDEAL: A methology for developing information systems

    NASA Technical Reports Server (NTRS)

    Evers, Ken H.; Bachert, Robert F.

    1988-01-01

    As a result of improved capabilities obtained through current computer technologies, application programs and expert systems, Enterprises are being designed or upgraded to be highly integrated and automated information systems. To design or modify Enterprises, it is necessary to first define what functions are to be performed within the Enterprise, identify which functions are potential candidates for automation, and what automated or expert systems are available, or must be developed, to accomplish the selected function. Second, it is necessary to define and analyze the informational requirements for each function along with the informational relationships among the functions so that a database structure can be established to support the Enterprise. To perform this type of system design, an integrated set of analysis tools is required to support the information analysis process. The IDEAL (Integrated Design and Engineering Analysis Languages) methodology provides this integrated set of tools and is discussed.

  14. The Geometry of Non-Ideal Fluids

    NASA Astrophysics Data System (ADS)

    Rajeev, S. G.

    2013-12-01

    Arnold showed that the Euler equations of an ideal fluid describe geodesies on the Lie algebra of incompressible vector fields. We generalize this to fluids with dissipation and Gaussian random forcing. The dynamics is determined by the structure constants of a Lie algebra, along with inner products defining kinetic energy, Ohmic dissipation and the covariance of the forces. This allows us to construct tractable toy models for fluid mechanics with a finite number of degrees of freedom. We solve one of them to show how symmetries can be broken spontaneously.In another direction, we derive a deterministic equation that describes the most likely path connecting two points in the phase space of a randomly forced system: this is a WKB approximation to the Fokker-Plank-Kramer equation, analogous to the instantons of quantum theory. Applied to hydrodynamics, we derive a PDE system for Navier-Stokes instantons.

  15. Ideal scaling up of BETHSY experimental results

    SciTech Connect

    Petelin, S.; Mavko, B.; Ravnikar, I.

    1996-06-01

    The transient scenario of ISP-27 (International System Problem) was applied in the analysis for real NPP (Nuclear Power Plant). The scenario involves a diameter 5.1 cm (2 inches) cold leg break without available HPSI (High Pressure Safety Injection) and hypothetical operator procedure for secondary system depressurization. The objective was to evaluate the ideal scaling up of BETHSY (Boucle d`Etudes Thermohydraulique Systeme) facility proposed accident management procedure for real NPP and to compare the physical phenomena known from experimental background with the phenomena predicted by RELAP5 simulations of real plant transient. Also, special attention was concentrated on those parts of RELAP5 model where possible multidimensional phenomena may occur.

  16. Ideal ballooning modes in axisymmetric mirror machines

    SciTech Connect

    Baldwin, D.E.; McNamara, B.; Willmann, P.

    1980-12-15

    A simple code is described that finds marginally stable (..omega../sup 2/ = 0) ballooning-type MHD modes, localized about a field line in an axisymmetric, open-ended, plasma confinement device. The equations are based on a lower bound for the perturbed energy delta W, derived by W. Newcomb from the ideal MHD energy principle, and are cast in the form of a Ricatti equation for the first derivative of the eigenfunction, with the open boundary conditions that this derivative vanish at the plasma boundary down each field line. The input to the code is the two-dimensional shape of a field line, the field strength B(s), and parameters to define pressure profiles throughout the system. The objective is to find the highest plasma pressures for which the given line is MHD-stable.

  17. The Platonic Ideal of Stalactite Growth

    NASA Astrophysics Data System (ADS)

    Short, Martin; Toomey, Rickard

    2005-03-01

    The chemical mechanisms underlying the growth of cave formations such as stalactites are well-known, yet no theory has yet been proposed which successfully accounts for the dynamic evolution of their shapes. Here we consider the interplay of thin-film fluid dynamics, calcium carbonate chemistry, and CO2 transport in the cave to show that stalactites evolve according to a novel local geometric growth law which exhibits extreme amplification at the tip as a consequence of the locally-varying fluid layer thickness. Studies of this model show that a broad class of initial conditions is attracted to an ideal shape which is strikingly close to a statistical average of natural stalactites. A linear stability analysis shows is used to explain the instability of this state to the formation of centimeter-scale ripples, as commonly seen on a wide range of speleothem surfaces.

  18. The Platonic Ideal of Stalactite Growth

    NASA Astrophysics Data System (ADS)

    Short, Martin; Baygents, James; Beck, Warren; Stone, David; Goldstein, Raymond; Toomey, Rickard

    2004-11-01

    The chemical mechanisms underlying the growth of cave formations such as stalactites are well-known, yet no theory has yet been proposed which successfully accounts for the dynamic evolution of their shapes. Here we consider the interplay of thin-film fluid dynamics, calcium carbonate chemistry, and CO2 transport in the cave to show that stalactites evolve according to a novel local geometric growth law which exhibits extreme amplification at the tip as a consequence of the locally-varying fluid layer thickness. Studies of this model show that a broad class of initial conditions is attracted to an ideal shape which is strikingly close to a statistical average of natural stalactites.

  19. Stability of ideal fcc twin boundaries

    NASA Astrophysics Data System (ADS)

    Wright, T. W.; Daphalapurkar, N. P.; Ramesh, K. T.

    2014-12-01

    Ideas from continuum mechanics are used to derive an elastic stability inequality for a boundary between two different materials under quasi-static, homogeneous conditions. The terms in this inequality are interpreted for the case of an ideal twinning plane between two variants of a face-centered cubic material. High quality potentials for Ni and Cu are used in molecular dynamics calculations to calibrate relevant energies and displacements near the twinning plane. It is found that in comparison with direct molecular dynamics calculations the inequality predicts the critical stress that initiates movement of the twinning plane in Ni within 1.9% and within 1.3% for Cu. Although the predicted and calculated critical stresses are only upper bounds for the more realistic case of an imperfect boundary, the calculations give considerable insight into the interplay of energies that lead to boundary motion.

  20. Nonlinear current sheet formation in ideal plasmas

    NASA Technical Reports Server (NTRS)

    Voge, A.; Schindler, K.; Otto, A.

    1994-01-01

    We present a numerical study of the formation of current sheets in ideal plasmas. First we confirm the development of singular current sheets in a one-dimensional model. In a second step we extend the analysis to two-dimensional equilibria. Here it is found that the resulting structures are quiet insensitive to the boundary conditions. For the special case of a magnetotail like equilibrium it will be shown that the resulting current distribution provides a possibility to understand the onset of a localized anomalous resistivity from a macroscopic point of view. Furthermore, the resulting structures provide an explanation for the dramatic decrease of the thickness of the current sheet in the magnetotail prior to the onset of geomagnetic substorms.

  1. Earthshine simulator: Idealized images of the Moon

    NASA Astrophysics Data System (ADS)

    Thejll, Peter; Gleisner, Hans

    2016-12-01

    Terrestrial albedo can be determined from observations of the relative intensity of earthshine. Images of the Moon at different lunar phases can be analyzed to derive the semi-hemispheric mean albedo of the Earth, and an important tool for doing this is simulations of the appearance of the Moon for any time. This software produces idealized images of the Moon for arbitrary times. It takes into account the libration of the Moon and the distances between Sun, Moon and the Earth, as well as the relevant geometry. The images of the Moon are produced as FITS files. User input includes setting the Julian Day of the simulation. Defaults for image size and field of view are set to produce approximately 1x1 degree images with the Moon in the middle from an observatory on Earth, currently set to Mauna Loa.

  2. Ideal magnetohydrodynamic stability of the spheromak configuration

    SciTech Connect

    Jardin, S.C.

    1982-01-19

    Results are presented of a parametric study of the ideal magnetohydrodynamic stability properties of the spheromak, or compact torus, configuration. In the absence of a nearby conducting wall, the spheromak is always unstable to at least one current driven mode. With a conducting wall at the surface, the spheromak can be unstable to current driven modes if the current is too peaked, i.e., q/sub o/(R/a) less than or equal to 2/3, or if the shear is too low at the origin. The Mercier criterion sets an upper limit on the pressure gradient everywhere, but configurations that are everywhere Mercier stable can be unstable to pressure driven low-n modes. Stable toroidal configurations exist with a spherical wall separated by half a minor radius, and with ..beta../sub theta/ = 30%.

  3. First principle thousand atom quantum dot calculations

    SciTech Connect

    Wang, Lin-Wang; Li, Jingbo

    2004-03-30

    A charge patching method and an idealized surface passivation are used to calculate the single electronic states of IV-IV, III-V, II-VI semiconductor quantum dots up to a thousand atoms. This approach scales linearly and has a 1000 fold speed-up compared to direct first principle methods with a cost of eigen energy error of about 20 meV. The calculated quantum dot band gaps are parametrized for future references.

  4. On controlling nonlinear dissipation in high order filter methods for ideal and non-ideal MHD

    NASA Technical Reports Server (NTRS)

    Yee, H. C.; Sjogreen, B.

    2004-01-01

    The newly developed adaptive numerical dissipation control in spatially high order filter schemes for the compressible Euler and Navier-Stokes equations has been recently extended to the ideal and non-ideal magnetohydrodynamics (MHD) equations. These filter schemes are applicable to complex unsteady MHD high-speed shock/shear/turbulence problems. They also provide a natural and efficient way for the minimization of Div(B) numerical error. The adaptive numerical dissipation mechanism consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is very general. The objective of this paper is to investigate the performance of three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD.

  5. Cooperatively enhanced dipole forces from artificial atoms in trapped nanodiamonds

    NASA Astrophysics Data System (ADS)

    Juan, Mathieu L.; Bradac, Carlo; Besga, Benjamin; Johnsson, Mattias; Brennen, Gavin; Molina-Terriza, Gabriel; Volz, Thomas

    2017-03-01

    Optical trapping is a powerful tool to manipulate small particles, from micrometre-size beads in liquid environments to single atoms in vacuum. The trapping mechanism relies on the interaction between a dipole and the electric field of laser light. In atom trapping, the dominant contribution to the associated force typically comes from the allowed optical transition closest to the laser wavelength, whereas for mesoscopic particles it is given by the polarizability of the bulk material. Here, we show that for nanoscale diamond crystals containing a large number of artificial atoms, nitrogen-vacancy colour centres, the contributions from both the nanodiamond and the colour centres to the optical trapping strength can be simultaneously observed in a noisy liquid environment. For wavelengths around the zero-phonon line transition of the colour centres, we observe a 10% increase of overall trapping strength. The magnitude of this effect suggests that due to the large density of centres, cooperative effects between the artificial atoms contribute to the observed modification of the trapping strength. Our approach may enable the study of cooperativity in nanoscale solid-state systems and the use of atomic physics techniques in the field of nano-manipulation.

  6. Nonlinear electrophoresis of ideally polarizable particles

    NASA Astrophysics Data System (ADS)

    Figliuzzi, B.; Chan, W. H. R.; Moran, J. L.; Buie, C. R.

    2014-10-01

    We focus in this paper on the nonlinear electrophoresis of ideally polarizable particles. At high applied voltages, significant ionic exchange occurs between the electric double layer, which surrounds the particle, and the bulk solution. In addition, steric effects due to the finite size of ions drastically modify the electric potential distribution in the electric double layer. In this situation, the velocity field, the electric potential, and the ionic concentration in the immediate vicinity of the particle are described by a complicated set of coupled nonlinear partial differential equations. In the general case, these equations must be solved numerically. In this study, we rely on a numerical approach to determine the electric potential, the ionic concentration, and the velocity field in the bulk solution surrounding the particle. The numerical simulations rely on a pseudo-spectral method which was used successfully by Chu and Bazant [J. Colloid Interface Sci. 315(1), 319-329 (2007)] to determine the electric potential and the ionic concentration around an ideally polarizable metallic sphere. Our numerical simulations also incorporate the steric model developed by Kilic et al. [Phys. Rev. E 75, 021502 (2007)] to account for crowding effects in the electric double layer, advective transport, and for the presence of a body force in the bulk electrolyte. The simulations demonstrate that surface conduction significantly decreases the electrophoretic mobility of polarizable particles at high zeta potential and at high applied electric field. Advective transport in the electric double layer and in the bulk solution is also shown to significantly impact surface conduction.

  7. Idealized simulations of sting jet cyclones

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Gray, S. L.; Clark, P. A.

    2012-04-01

    An idealized modeling study of sting-jet cyclones is presented. Sting jets are descending mesoscale jets that occur in some extratropical cyclones and produce localized regions of strong low-level winds in the frontal fracture region. Moist baroclinic lifecycle (LC1) simulations are performed with modifications to produce cyclones resembling observed sting-jet cyclones. Two jets exist in the control idealized cyclone that descend into the frontal fracture region and result in strong winds near to the top of the boundary layer; one of these satisfies the criteria for a sting jet, the other is associated with the warm front. Sensitivity experiments show that both these jets are robust features. The sting jet strength (measured by maximum low-level wind speed or descent rate) increases with the cyclone growth rate; growth rate increases with increasing basic-state zonal jet maximum or decreasing basic-state tropospheric static stability. The two cyclones with the weakest basic-state static stability have by far the strongest sting jets, with descent rates comparable to those observed. Evaporative cooling contributes up to 20% of the descent rate in these sting jets compared with up to 4% in the other sting jets. Conditional symmetric instability (CSI) release in the cloud head also contributes to the sting jet, although there is less extensive CSI than in observed cases. The robustness of the sting jets suggests that they could occur frequently in cyclones with frontal fracture; however, they are unlikely to be identified unless momentum transport through the boundary layer leads to strong surface wind gusts.

  8. The International Centre for Theoretical Physics

    NASA Astrophysics Data System (ADS)

    Hussain, Faheem

    2008-07-01

    This talk traces in brief the genesis of the Abdus Salam International Centre for Theoretical Physics, Trieste, as one of Prof. Abdus Salam's major achievements. It outlines why Salam felt the necessity for establishing such a centre to help physicists in the developing world. It situates the founding of the Centre within Salam's broader vision of the causes of underdevelopment and of science as an engine for scientific, technological, economic and social development. The talk reviews the successes and failures of the ICTP and gives a brief overall view of the current status of the Centre.

  9. From the ideal market to the ideal clinic: constructing a normative standard of fairness for human subjects research.

    PubMed

    Phillips, Trisha

    2011-02-01

    Preventing exploitation in human subjects research requires a benchmark of fairness against which to judge the distribution of the benefits and burdens of a trial. This paper proposes the ideal market and its fair market price as a criterion of fairness. The ideal market approach is not new to discussions about exploitation, so this paper reviews Wertheimer's inchoate presentation of the ideal market as a principle of fairness, attempt of Emanuel and colleagues to apply the ideal market to human subjects research, and Ballantyne's criticisms of both the ideal market and the resulting benchmark of fairness. It argues that the criticism of this particular benchmark is on point, but the rejection of the ideal market is mistaken. After presenting a complete account of the ideal market, this paper proposes a new method for applying the ideal market to human subjects research and illustrates the proposal by considering a sample case.

  10. Super-Coulombic atom-atom interactions in hyperbolic media

    NASA Astrophysics Data System (ADS)

    Cortes, Cristian L.; Jacob, Zubin

    2017-01-01

    Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.

  11. Super-Coulombic atom-atom interactions in hyperbolic media.

    PubMed

    Cortes, Cristian L; Jacob, Zubin

    2017-01-25

    Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.

  12. Person-centred care dialectics-Inquired in the context of palliative care.

    PubMed

    Öhlén, Joakim; Reimer-Kirkham, Sheryl; Astle, Barbara; Håkanson, Cecilia; Lee, Joyce; Eriksson, Marjukka; Sawatzky, Richard

    2017-10-01

    Although a widely used concept in health care, person-centred care remains somewhat ambiguous. In the field of palliative care, person-centred care is considered a historically distinct ideal and yet there continues to be a dearth of conceptual clarity. Person-centred care is also challenged by the pull of standardization that characterizes much of health service delivery. The conceptual ambiguity becomes especially problematic in contemporary pluralistic societies, particularly in the light of continued inequities in healthcare access and disparities in health outcomes. Our aim was to explicate premises and underlying assumptions regarding person-centred care in the context of palliative care with an attempt to bridge the apparently competing agendas of individualization versus standardization, and individuals versus populations. By positioning person-centredness in relation to the hermeneutics of the self according to Paul Ricœur, dialectics between individualization and standardization, and between individuals and populations were constructed. The competing agendas were related in a dialectic manner in the way that population health is of importance for the individual, and standardization is of importance for the population. The analysis suggests that person-centred care is an ethical stance, which gives prominence to both suffering and capability of the individual as a person. The dialectic analysis points towards the importance of extending person-centred care to encompass population and societal perspectives and thereby avoiding a problematic tendency of affiliating person-centred care with exclusively individualistic perspectives. Considerations for person-centred palliative care on micro-, meso- and macrolevels conclude the paper. © 2017 John Wiley & Sons Ltd.

  13. Atomic Energy Basics, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  14. European guidelines for the accreditation of Sleep Medicine Centres.

    PubMed

    Pevernagie, Dirk

    2006-06-01

    This document describes guidelines for accreditation of Sleep Medicine Centres in Europe. These guidelines are the result of a consensus procedure, in which representatives of the European Sleep Research Society (ESRS) and representatives of different European National Sleep Societies (ENSS) were involved. The information obtained during different rounds of consultation was gathered and processed by the members of the Steering Committee of the ESRS. The scope of the guidelines is to define the characteristics of multidisciplinary Sleep Medicine Centres (SMCs), in terms of requirements regarding staff, operational procedures and logistic facilities. Accreditation of SMCs is proposed to be the responsibility of the individual ENSS. The Accreditation Guidelines may thus be considered an instrument for the national societies to develop new or standardize existing accreditation questionnaires, as well as procedures for visiting the site, drafting the accreditation report, and finally, granting the accreditation. The Accreditation Guidelines are meant to be a line of action, that ideally should be followed as close as possible, but that may be subject to certain exceptions, depending on local customs or regulations.

  15. Star Formation and Dynamics in the Galactic Centre

    NASA Astrophysics Data System (ADS)

    Mapelli, Michela; Gualandris, Alessia

    The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ˜ 0.04 pc, while the S-stars, i.e. the ˜ 30 stars closest to the SMBH ( lesssim 0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.

  16. The art and science of debriefing in simulation: Ideal and practice.

    PubMed

    Dieckmann, Peter; Molin Friis, Susanne; Lippert, Anne; Ostergaard, Doris

    2009-07-01

    Describing what simulation centre leaders see as the ideal debriefing for different simulator courses (medical vs. crisis resource management (CRM)-oriented). Describing the practice of debriefing based on interactions between instructors and training participants. Study 1 - Electronic questionnaire on the relevance of different roles of the medical teacher for debriefing (facilitator, role model, information provider, assessor, planner, resource developer) sent to simulation centre leaders. Study 2 - Observation study using a paper-and-pencil tool to code interactions during debriefings in simulation courses for CRM for content (medical vs. CRM-oriented) and type (question vs. utterance). Study 1 - The different roles were seen as equally important for both course types with the exception of 'information provider' which was seen as more relevant for medical courses. Study 2 - There were different interaction patterns during debriefings: line - involving mostly the instructor and one course participant, triangle - instructor and two participants, fan - instructor and all participants in a dyadic form and net - all participants and the instructor with cross references. What simulation centre heads think is important for the role mix of simulation instructors is (at least partly) not reflected in debriefing practice.

  17. Ideal cylindrical cloak: perfect but sensitive to tiny perturbations.

    PubMed

    Ruan, Zhichao; Yan, Min; Neff, Curtis W; Qiu, Min

    2007-09-14

    A cylindrical wave expansion method is developed to obtain the scattering field for an ideal two-dimensional cylindrical invisibility cloak. A near-ideal model of the invisibility cloak is set up to solve the boundary problem at the inner boundary of the cloak shell. We confirm that a cloak with the ideal material parameters is a perfect invisibility cloak by systematically studying the change of the scattering coefficients from the near-ideal case to the ideal one. However, because of the slow convergence of the zeroth-order scattering coefficients, a tiny perturbation on the cloak would induce a noticeable field scattering and penetration.

  18. Concepts of Self, Ideal Self, and Ideal Woman Held by College Men and Women: A Comparison Study.

    ERIC Educational Resources Information Center

    Voss, Jacqueline

    1980-01-01

    Married and single male and female college students of 1966, 1973, and 1976 are compared in their perceptions of female sex role--self, ideal woman, and man's ideal woman. Differences between perceptions of the ideal woman espoused by males and females were the most significant findings. (Author)

  19. An Efficient Trap of ^221Fr Atoms

    NASA Astrophysics Data System (ADS)

    Lu, Z. T.; Corwin, K. L.; Vogel, K. R.; Wieman, C. E.; Dinneen, T. P.; Maddi, J. A.; Gould, H.

    1997-04-01

    Francium, the heaviest alkali, is the ideal candidate for the next generation of experiments that study atomic parity non-conservation (PNC) effects or search for a CP-violating permanent atomic electric dipole moment (EDM). Since all francium isotopes are radioactive and have half-lives of 22 minutes or less, a highly efficient atom trap is needed to provide a sufficient sample for PNC or EDM experiments. Using an improved vapor cell magneto-optical trap, we have demonstrated an efficient trap of ^221Fr(t_1/2=5min) atoms. Over 20% of the ^221Fr atoms entering the cell are loaded into the trap. The 4cm cube cell has a geometry optimized for a high trap loading rate and its walls are coated with dryfilm to slow the loss of francium atoms to the walls (M.Stephens and C.Wieman, Phys. Rev. Lett. 72, 3787 (1994).). Produced from the decay of ^225Ac(t_1/2=10d), the francium atoms are efficiently transferred into the cell using a novel orthotropic oven (T.Dinneen, A.Ghiorso, and H.Gould, Rev. Sci. Inst. 67, 752 (1996).). Work supported by NSF, ONR,and U.S.DOE under contract number DE-AC-76SF00098.

  20. Nonlinear atom interferometer surpasses classical precision limit.

    PubMed

    Gross, C; Zibold, T; Nicklas, E; Estève, J; Oberthaler, M K

    2010-04-22

    Interference is fundamental to wave dynamics and quantum mechanics. The quantum wave properties of particles are exploited in metrology using atom interferometers, allowing for high-precision inertia measurements. Furthermore, the state-of-the-art time standard is based on an interferometric technique known as Ramsey spectroscopy. However, the precision of an interferometer is limited by classical statistics owing to the finite number of atoms used to deduce the quantity of interest. Here we show experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose-Einstein condensate. Controlled interactions between the atoms lead to non-classical entangled states within the interferometer; this represents an alternative approach to the use of non-classical input states. Extending quantum interferometry to the regime of large atom number, we find that phase sensitivity is enhanced by 15 per cent relative to that in an ideal classical measurement. Our nonlinear atomic beam splitter follows the 'one-axis-twisting' scheme and implements interaction control using a narrow Feshbach resonance. We perform noise tomography of the quantum state within the interferometer and detect coherent spin squeezing with a squeezing factor of -8.2 dB (refs 11-15). The results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.

  1. Deviations from Ideal Sublimation Vapor Pressure Behavior in Mixtures of Polycyclic Aromatic Compounds with Interacting Heteroatoms.

    PubMed

    Goldfarb, Jillian L; Suuberg, Eric M

    2010-08-01

    Despite the relatively small atomic fraction of a given heteroatom in a binary mixture of polycyclic aromatic compounds (PAC), the inclusion of heteroatomic substituted compounds can significantly impact mixture vapor pressure behavior over a wide range of temperatures. The vapor pressures of several binary PAC mixtures containing various heteroatoms show varying behavior, from practically ideal behavior following Raoult's law to significant deviations from ideality depending on the heteroatom(s) present in the mixture. Mixtures were synthesized using the quench-cool technique with equimolar amounts of two PAC, both containing heteroatoms such as aldehyde, carboxyl, nitrogen, and sulfur substituent groups. For some mixtures, deviation from ideality is inversely related to temperature, though in other cases we see deviations from ideality increasing with temperature, whereas some appear independent of temperature. Most commonly we see lower vapor pressures than predicted by Raoult's law, which indicates that the interacting heteroatoms prefer the solid mixture phase as opposed to the vapor phase. Although negative deviations predominate from Raoult's Law, the varying mixtures investigated show both higher and lower enthalpies and entropies of sublimation than predicted. In each mixture, a higher enthalpy of sublimation leads to higher entropy of sublimation than predicted, and vice versa.

  2. Cross-sectional analysis of deprivation and ideal cardiovascular health in the Paris Prospective Study 3.

    PubMed

    Empana, J P; Perier, M C; Singh-Manoux, A; Gaye, B; Thomas, F; Prugger, C; Plichart, M; Wiernik, E; Guibout, C; Lemogne, C; Pannier, B; Boutouyrie, P; Jouven, X

    2016-12-01

    We hypothesised that deprivation might represent a barrier to attain an ideal cardiovascular health (CVH) as defined by the American Heart Association (AHA). The baseline data of 8916 participants of the Paris Prospective Study 3, an observational cohort on novel markers for future cardiovascular disease, were used. The AHA 7-item tool includes four health behaviours (smoking, body weight, physical activity and optimal diet) and three biological measures (blood cholesterol, blood glucose and blood pressure). A validated 11-item score of individual material and psychosocial deprivation, the Evaluation de la Précarité et des Inégalités dans les Centres d'Examens de Santé-Evaluation of Deprivation and Inequalities in Health Examination centres (EPICES) score was used. The mean age was 59.5 years (standard deviation 6.2), 61.2% were men and 9.98% had an ideal CVH. In sex-specific multivariable polytomous logistic regression, the odds ratio (OR) for ideal behavioural CVH progressively decreased with quartile of increasing deprivation, from 0.54 (95% CI 0.41 to 0.72) to 0.49 (0.37 to 0.65) in women and from 0.61 (0.50 to 0.76) to 0.57 (0.46 to 0.71) in men. Associations with ideal biological CVH were confined to the most deprived women (OR=0.60; 95% CI 0.37 to 0.99), whereas in men, greater deprivation was related to higher OR of intermediate biological CVH (OR=1.28; 95% CI 1.05 to 1.57 for the third quartile vs the first quartile). Higher material and psychosocial deprivation may represent a barrier to reach an ideal CVH. NCT00741728. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  3. Propping up pharma's (natural) neoliberal phallic man: pharmaceutical representations of the ideal sexuopharmaceutical user.

    PubMed

    Gurevich, Maria; Leedham, Usra; Brown-Bowers, Amy; Cormier, Nicole; Mercer, Zara

    2017-04-01

    Contemporary social theorists emphasise the cultural quest for authenticity under conditions of increasing artificiality. Within this context, the body is commonly treated as an 'unfinished' surface requiring ongoing transformation to fulfil identity obligations. In this paper, we examine one such identity authentication project in the form of marketing of men's sexuopharmaceuticals. We use online pharmaceutical advertising for four approved sexuopharmaceuticals (Viagra, Cialis, STAXYN and Stendra) to describe the ideal neoliberal consumer. These campaigns underscore the robust role of pharmaceuticals in sexual authentication projects undergirded by neoliberal consumerist and aspirationalist ideals. Penile dependability as a luxury consumerist project reinvigorates traditional sexual (masculine) authentication as yoked to phallic control, by repackaging sexual enhancement medication use as a neoliberal beacon of aspirational achievements. The ideal targeted user is increasingly younger, and consumption of sexuopharmaceuticals is represented as achieving elite status and exclusive pleasures; masculine authenticity and choice; progressive relationships and a contemporary urban, fast-paced life; and a prepared yet spontaneous romantic sexuality. Women are also increasingly used in promotional materials directed at men; their responsibility centres on coaching and coaxing potential users.

  4. Atom Probe Tomography of Geomaterials

    NASA Astrophysics Data System (ADS)

    Parman, S. W.; Diercks, D.; Gorman, B.; Cooper, R. F.

    2013-12-01

    From the electron microprobe to the secondary ion microprobe to laser-ablation ICP-MS, steady improvements in the spatial resolution and detection limits of geochemical micro-analysis have been central to generating new discoveries. Atom probe tomography (APT) is a relatively new technology that promises nm-scale spatial resolution (in three dimensions) with ppm level detection limits. The method is substantially different from traditional beam-based (electron, ion, laser) methods. In APT, the sample is shaped (usually with a dual-beam FIB) into a needle with typical dimensions of 1-2 μm height and 100-200 nm diameter. Within the atom probe, the needle is evaporated one atom (ideally) at a time by a high electric field (ten's of V per square nm at the needle tip). A femtosecond laser (12 ps pulse width) is used to assist in evaporating non-conducting samples. The two-dimensional detector locates where the atom was released from the needle's surface and so can reconstruct the positions of all detected atoms in three dimensions. It also records the time of flight of the ion, which is used to calculate the mass/charge ratio of the ion. We will discuss our results analyzing a range of geologic materials. In one case, naturally occurring platinum group alloys (PGA) from the Josephine Ophiolite have been imaged. Such alloys are of interest as recorders of the Os heterogeneity of the mantle [1,2]. Optimal ablation was achieved with a laser power of 120-240 pJ and laser pulse rates 500 kHz. Runs were stopped after 10 million atoms were imaged. An example analysis is: Pt 61(1), Fe 26.1(9), Rh 1.20(4), Ir 7.0(7), Ni 2.65(8), Ru 0.20(9), Cu 1.22(8), Co 0.00029(5). Values are in atomic %; values in parentheses are one-sigma standard deviations on five separate needles from the same FIB lift-out, which was 30 μm long. Assuming the sample is homogenous over the 30 μm from which the needle was extracted, the analyses suggest relative errors for major elements below 5% and for

  5. The European NEO Coordination Centre

    NASA Astrophysics Data System (ADS)

    Perozzi, E.; Borgia, B.; Micheli, M.

    An operational approach to NEO (Near-Earth Object) hazard monitoring has been developed at European level within the framework of the Space Situational Awareness Program (SSA) of the European Space Agency (ESA). Through federating European assets and profiting of the expertise developed in European Universities and Research Centers, it has been possible to start the deployment of the so-called SSA NEO Segment. This initiative aims to provide a significant contribution to the worldwide effort to the discovery, follow-up and characterization of the near-Earth object population. A major achievement has been the inauguration in May 2013 of the ESA NEO Coordination Centre located at ESRIN (Frascati, Italy). The goal of the NEOCC Precursor Service operations is twofold: to make available updated information on the NEO population and the associated hazard and to contribute to optimize the NEO observational efforts. This is done by maintaining and improving a Web Portal publicly available at http://neo.ssa.esa.int and by performing follow-up observations through a network of collaborating telescopes and facilities. An overview of the SSA-NEO System and a summary of the first two years of NEOCC operations is presented.

  6. Capturing Reality at Centre Block

    NASA Astrophysics Data System (ADS)

    Boulanger, C.; Ouimet, C.; Yeomans, N.

    2017-08-01

    The Centre Block of Canada's Parliament buildings, National Historic Site of Canada is set to undergo a major rehabilitation project that will take approximately 10 years to complete. In preparation for this work, Heritage Conservation Services (HCS) of Public Services and Procurement Canada has been completing heritage documentation of the entire site which includes laser scanning of all interior rooms and accessible confined spaces such as attics and other similar areas. Other documentation completed includes detailed photogrammetric documentation of rooms and areas of high heritage value. Some of these high heritage value spaces present certain challenges such as accessibility due to the height and the size of the spaces. Another challenge is the poor lighting conditions, requiring the use of flash or strobe lighting to either compliment or completely eliminate the available ambient lighting. All the spaces captured at this higher level of detail were also captured with laser scanning. This allowed the team to validate the information and conduct a quality review of the photogrammetric data. As a result of this exercise, the team realized that in most, if not all cases, the photogrammetric data was more detailed and at a higher quality then the terrestrial laser scanning data. The purpose and motivation of this paper is to present these findings, as well provide the advantages and disadvantages of the two methods and data sets.

  7. The Irish Centre for Talented Youth

    ERIC Educational Resources Information Center

    Gilheany, Sheila

    2005-01-01

    Conducting potency tests on penicillin, discussing rocket technology with a NASA astronaut, analysing animal bone fragments from medieval times, these are just some of the activities which occupy the time of students at The Irish Centre for Talented Youth. The Centre identifies young students with exceptional academic ability and then provides…

  8. Student-Centred Learning (SCL): Roles Changed?

    ERIC Educational Resources Information Center

    Onurkan Aliusta, Gülen; Özer, Bekir

    2017-01-01

    This paper addresses the espoused and enacted practices of high school teachers with regard to student-centred learning (SCL). Explanatory mixed-method design, where quantitative strand is followed by qualitative one, is employed. While the quantitative strand aims to explore teachers' perceptions regarding the extent student-centred teacher and…

  9. Promotion in Call Centres: Opportunities and Determinants

    ERIC Educational Resources Information Center

    Gorjup, Maria Tatiana; Valverde, Mireia; Ryan, Gerard

    2008-01-01

    Purpose: The purpose of this paper is to examine the quality of jobs in call centres by focusing on the opportunities for promotion in this sector. More specifically, the research questions focus on discovering whether promotion is common practise in the call centre sector and on identifying the factors that affect this.…

  10. [The Adamant, an unusual care centre].

    PubMed

    Khidichian, Frédéric

    2011-01-01

    The day care centre of the central Paris area has established itself in an unusual location--a 650 m2 floating building moored on the right bank of the Seine. Patients and caregivers were involved in the design of this original and ecological care centre, which places the emphasis on comfort and safety.

  11. Student Centred Approaches: Teachers' Learning and Practice

    ERIC Educational Resources Information Center

    Vale, Colleen; Davies, Anne; Weaven, Mary; Hooley, Neil

    2010-01-01

    Student centred approaches to teaching and learning in mathematics is one of the reforms currently being advocated and implemented to improve mathematics outcomes for students from low socio-economic status (SES) backgrounds. The models, meanings and practices of student centred approaches explored in this paper reveal that a constructivist model…

  12. Promotion in Call Centres: Opportunities and Determinants

    ERIC Educational Resources Information Center

    Gorjup, Maria Tatiana; Valverde, Mireia; Ryan, Gerard

    2008-01-01

    Purpose: The purpose of this paper is to examine the quality of jobs in call centres by focusing on the opportunities for promotion in this sector. More specifically, the research questions focus on discovering whether promotion is common practise in the call centre sector and on identifying the factors that affect this.…

  13. The European standards of Haemophilia Centres

    PubMed Central

    Giangrande, Paul; Calizzani, Gabriele; Menichini, Ivana; Candura, Fabio; Mannucci, Pier Mannuccio; Makris, Michael

    2014-01-01

    Introduction The European haemophilia community of professionals and patients has agreed on the principles of haemophilia care to address comprehensive optimal delivery of care which is nowadays scattered throughout Europe. Many of the health facilities call themselves Haemophilia Centres despite their variation in size, expertise and services provided. Only a small number of countries have Haemophilia Centre accreditation systems in place. Methods In the framework of the European Haemophilia Network project, following an inclusive process of stakeholder involvement, the European Guidelines for the certification of haemophilia centres have been developed in order to set quality standards for European Haemophilia Centres and criteria for their certification. Results The Guidelines define the standards and criteria for the designation of two levels of care delivery: European Haemophilia Treatment Centres, providing local routine care, and European Haemophilia Comprehensive Care Centres, providing specialised and multi-disciplinary care and functioning as tertiary referral centres. Additionally, they define standards about general requirements, patient care, provision of an advisory service and establishment of network of clinical and specialised services. Conclusions The implementation of the European Guidelines for the certification of Haemophilia Centres will contribute to the reduction of health inequalities through the standardisation of quality of care in European Union Member States and could represent a model to be taken into consideration for other rare disease groups. PMID:24922293

  14. The Irish Centre for Talented Youth

    ERIC Educational Resources Information Center

    Gilheany, Sheila

    2005-01-01

    Conducting potency tests on penicillin, discussing rocket technology with a NASA astronaut, analysing animal bone fragments from medieval times, these are just some of the activities which occupy the time of students at The Irish Centre for Talented Youth. The Centre identifies young students with exceptional academic ability and then provides…

  15. The Press Research Centre, 1956-1976.

    ERIC Educational Resources Information Center

    Press Research Centre, Krakow (Poland).

    In 1956, the Press Research Centre was established in Cracow, Poland by a group of journalists and publishers, for the purpose of instituting press research that would have practical applications. The aims of the Centre were to conduct studies on the history of the Polish press, the contemporary press, press readership, and editorial techniques.…

  16. Analysis of three idealized reactor configurations: plate, pin, and homogeneous. [LMFBR

    SciTech Connect

    McKnight, R.D.

    1983-01-01

    Detailed Monte Carlo calculations have been performed for three distinct configurations of an idealized fast critical assembly. This idealized assembly was based on the LMFBR benchmark critical assembly ZPR-6/7. In the first configuration, the entire core was loaded with the plate unit cell of ZPR-6/7. In the second configuration, the entire core was loaded with the ZPR sodium-filled pin calandria. The actual ZPR pin calandria are loaded with mixed (U,Pu) oxide pins which closely match the composition of the ZPR-6/7 plate unit cell. For the present study, slight adjustments were made in the atom concentrations and the length of the pin calandria in order to make the core boundaries and average composition for the pin-cell configuration identical to those of the plate-cell configuration. In the third configuration, the core was homogeneous, again with identical core boundaries and average composition as the plate and pin configurations.

  17. Analytical pair correlations in ideal quantum gases: temperature-dependent bunching and antibunching.

    PubMed

    Bosse, J; Pathak, K N; Singh, G S

    2011-10-01

    The fluctuation-dissipation theorem together with the exact density response spectrum for ideal quantum gases has been utilized to yield a new expression for the static structure factor, which we use to derive exact analytical expressions for the temperature-dependent pair distribution function g(r) of the ideal gases. The plots of bosonic and fermionic g(r) display "Bose pile" and "Fermi hole" typically akin to bunching and antibunching as observed experimentally for ultracold atomic gases. The behavior of spin-scaled pair correlation for fermions is almost featureless, but bosons show a rich structure including long-range correlations near T(c). The coherent state at T=0 shows no correlation at all, just like single-mode lasers. The depicted decreasing trend in correlation with decrease in temperature for T

  18. The Galactic Centre - A spectroscopic and imaging study with the LWS

    NASA Astrophysics Data System (ADS)

    White, G. J.; Smith, H. A.; Stacey, G. J.; Fischer, J.; Spinoglio, L.; Baluteau, J. P.; Cernicharo, J.; Bradford, C. M.

    1999-03-01

    We report observations of a fully sampled (spatially and spectrally) mapping of the central few arcminutes around the Galactic Centre, using the ISO LWS. The maps show the relative spatial distributions in about 20 different emission and absorption lines. The circumnuclear disc is clearly traced by some molecular lines, whilst the central region dominates in other atomic and ionised lines. Spectra are also be shown of several other interesting sources within the Galactic Centre cloud ensemble, including Sgr A West and the `Sickle' cluster.

  19. The great galactic centre mystery

    NASA Technical Reports Server (NTRS)

    Riegler, G. R.

    1982-01-01

    Gamma-ray observations of the center of the Galaxy show a varying positron-electron annihilation radiation emission, while at radio wavelengths a non-thermal compact source surrounded by ionized gas moving at high velocities can be seen. Line emission maps for atomic and ionized hydrogen and molecular gas suggest gas expulsion and a massive collapsed object. IR observations show that ionized gas in the central few parsecs of the Galactic center is concentrated in at least 14 small clouds. Charge-coupled device images show a pair of faint, very red sources within a few arc seconds of IRS 16 and the compact non-thermal radio source. The positron-electron annihilation line emission implies an annihilation rate of 10 to the 43rd per sec, compared with an observed luminosity at IR wavelengths of 10 to the 40 erg per sec. Some models are briefly discussed.

  20. A full ranking for decision making units using ideal and anti-ideal points in DEA.

    PubMed

    Barzegarinegad, A; Jahanshahloo, G; Rostamy-Malkhalifeh, M

    2014-01-01

    We propose a procedure for ranking decision making units in data envelopment analysis, based on ideal and anti-ideal points in the production possibility set. Moreover, a model has been introduced to compute the performance of a decision making unit for these two points through using common set of weights. One of the best privileges of this method is that we can make ranking for all decision making units by solving only three programs, and also solving these programs is not related to numbers of decision making units. One of the other advantages of this procedure is to rank all the extreme and nonextreme efficient decision making units. In other words, the suggested ranking method tends to seek a set of common weights for all units to make them fully ranked. Finally, it was applied for different sets holding real data, and then it can be compared with other procedures.

  1. Ideal thermodynamic processes of oscillatory-flow regenerative engines will go to ideal stirling cycle?

    NASA Astrophysics Data System (ADS)

    Luo, Ercang

    2012-06-01

    This paper analyzes the thermodynamic cycle of oscillating-flow regenerative machines. Unlike the classical analysis of thermodynamic textbooks, the assumptions for pistons' movement limitations are not needed and only ideal flowing and heat transfer should be maintained in our present analysis. Under such simple assumptions, the meso-scale thermodynamic cycles of each gas parcel in typical locations of a regenerator are analyzed. It is observed that the gas parcels in the regenerator undergo Lorentz cycle in different temperature levels, whereas the locus of all gas parcels inside the regenerator is the Ericson-like thermodynamic cycle. Based on this new finding, the author argued that ideal oscillating-flow machines without heat transfer and flowing losses is not the Stirling cycle. However, this new thermodynamic cycle can still achieve the same efficiency of the Carnot heat engine and can be considered a new reversible thermodynamic cycle under two constant-temperature heat sinks.

  2. The loss of idealism throughout internship.

    PubMed

    Griffith, Charles H; Wilson, John F

    2003-12-01

    The purpose of this project was to understand how resident attitudes to specific types of patients change throughout their internship. Over a 3-year period all 1st-year internal medicine residents were asked to complete a 15-item survey regarding their attitudes toward certain patient types and the profession. The survey was administered the 1st day of the internship, again in mid-November, and in June in the last month of internship. Sixty-one of 80 interns (76% response) completed all three administrations of the survey. In general, there were statistically significant differences in attitudes from the first administration to the second in all categories (all changes reflecting less idealism), with attitudes remaining the same for the second to third administration. For example, interns believed significantly more patients requesting narcotics were drug seekers (19% vs. 33%/37%, p < .0001) and a lesser percentage of the elderly could care for themselves independently (62% vs. 50%/48%, p < .0001). We conclude interns become less idealistic toward patients and the profession throughout internship, with the greatest change within the first 5 months.

  3. Ideal bulk pressure of active Brownian particles.

    PubMed

    Speck, Thomas; Jack, Robert L

    2016-06-01

    The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here, we study the simplest model, an ideal gas of noninteracting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

  4. Theory of ideal orifice pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    David, M.; Maréchal, J.-C.; Simon, Y.; Guilpin, C.

    The main purpose of this paper is to explain the operation of the orifice pulse tube refrigerator (OPTR). An analytical model of the ideal OPT has been developed. The mechanism of heat flow at the tube ends is clearly explained as the result of the hysteretic process of the elements of gas entering and leaving the tube. The motion of the buffer gas is deduced by numerical integration and the expected balance equation for the heat flows at the hot and cold exchangers is established. A numerical calculation of the velocity profile along the pulse tube is in good agreement with hot-wire anemometry data. In working conditions, we found, for the gross refrigeration power, < q˙>, theory/experiment ratios as low as 1.2, whereas those previously reported by Storch and Radebaugh were about 3 - 5. The differences between the theory of Radebaugh et al. and our model are following: (1) Radebaugh and co-workers assume small sinusoidal oscillations of the gas pressure in the tube ( ΔP/ P¯ « 1 ) whereas we describe the gas flow in the tube for any time-dependence of the pressure oscillation P( t); (2) In our model, < q˙>, is expressed with a minimum number of independent and controlled parameters relative to the OPT. In a double inlet pulse tube configuration, our test apparatus was able to achieve a 32 K temperature limit.

  5. [Tuberculosis and the modern ideal of living].

    PubMed

    Medici, T C

    2003-08-20

    Sunlight and fresh air belong to the everyday life's myths. It has influenced our times and personal lives as much as industrialization. Today we are hardly aware of the multiple and omnipresent consequences of this myth. The modern movement with all its facets including modern architecture is barely conceivable without it. What is the link between this triad with all its effects and tuberculosis, the oldest and most important infectious disease which still claims more than 3 million deaths per year worldwide? Tuberculosis was treated by sunlight and fresh air at all times. This treatment was at its zenith during the second half of the 19th century after Hermann Brehmer had initiated this treatment within sanatoria in 1862. The sanatorium vogue lasted until the middle of the last century when streptomycin was isolated by Selman Waksman 1943. A new type of hospital was necessary for treating the patients with sunlight and fresh air: the sanatorium with its wide windows, sheltered open balconies, terraces and "Liegehallen". In return, this airy type of building was the forrunner of a new architectural style, called "Neues Bauen". The latter has profoundly influenced our modern ideal of living since Le Corbusiier built the Villa Savoye, one of the architectural highlights of the 20th century.

  6. Activation of MHD reconnection on ideal timescales

    NASA Astrophysics Data System (ADS)

    Landi, S.; Papini, E.; Del Zanna, L.; Tenerani, A.; Pucci, F.

    2017-01-01

    Magnetic reconnection in laboratory, space and astrophysical plasmas is often invoked to explain explosive energy release and particle acceleration. However, the timescales involved in classical models within the macroscopic MHD regime are far too slow to match the observations. Here we revisit the tearing instability by performing visco-resistive two-dimensional numerical simulations of the evolution of thin current sheets, for a variety of initial configurations and of values of the Lunquist number S, up to 107. Results confirm that when the critical aspect ratio of S 1/3 is reached in the reconnecting current sheets, the instability proceeds on ideal (Alfvénic) macroscopic timescales, as required to explain observations. Moreover, the same scaling is seen to apply also to the local, secondary reconnection events triggered during the nonlinear phase of the tearing instability, thus accelerating the cascading process to increasingly smaller spatial and temporal scales. The process appears to be robust, as the predicted scaling is measured both in inviscid simulations and when using a Prandtl number P  =  1 in the viscous regime.

  7. Ideal Tearing in the Hall Regime

    NASA Astrophysics Data System (ADS)

    Pucci, F.; Velli, M.; Tenerani, A.

    2015-12-01

    Magnetic reconnection is generally believed to be the mechanism thatexplains explosive events in astrophysical plasmas, such as flares inthe solar corona, substorms. One of the main questions which remainsconcerns how magnetic reconnection may account for the fast magneticenergy conversion to kinetic and thermal energies. Recently it hasbeen shown by Pucci and Velli (2014) that, assuming that currentsheets scales as different powers of the magnetic Reynolds number S,the growth rate of the tearing mode instability in current sheetsincreases as the sheets thin and, once the thickness reaches a scalinga/L ˜ S-1/3, the time scale for the instability to develop becomesof the order of the Alfvén time. In Hall reconnection, dispersivewaves introduced by the Hall effect make the energy release ratesfaster. This effect becomes important to the collisional tearing modeinstability when the thickness of magnetic reversal layer iscomparable to the ion inertia length, where Hall currents produce athree-dimensional quadrupole structure of magnetic field. Here wepresent a linear study aiming to show how an "ideal tearing mode" isachieved when Hall effects are included, including scaling laws forsheet aspect ratios and growth rates.

  8. Ideal near-field thermophotovoltaic cells

    NASA Astrophysics Data System (ADS)

    Molesky, Sean; Jacob, Zubin

    2015-05-01

    We ask the question, what are the ideal characteristics of a near-field thermophotovoltaic cell? Our search leads us to a reformulation of near-field radiative heat transfer in terms of the joint density of electronic states of the emitter-absorber pair in the thermophotovoltaic system. This form reveals that semiconducting materials with narrowband absorption spectra are critical to the energy-conversion efficiency. This essential feature is unavailable in conventional bulk semiconductor cells but can be obtained using low-dimensional materials. Our results show that the presence of matched van Hove singularities resulting from quantum confinement in the emitter and absorber of a thermophotovoltaic cell boosts both the magnitude and spectral selectivity of radiative heat transfer, dramatically improving energy-conversion efficiency. We provide a model near-field thermophotovoltaic system design making use of this idea by employing the van Hove singularities present in carbon nanotubes. Shockley-Queisser analysis shows that the predicted heat transfer characteristics of this model device are fundamentally better than existing thermophotovoltaic designs. Our work paves the way for the use of quantum dots, quantum wells, two-dimensional semiconductors, semiconductor nanowires, and carbon nanotubes as future materials for thermophotovoltaic cells.

  9. Dust Resuspension due to Idealized Foot Motion

    NASA Astrophysics Data System (ADS)

    Sheth, Ritesh

    2005-11-01

    The air quality is affected by amount and types of particulate contaminants that are suspended in the air. The resuspension phenomena occur through two mechanisms: mechanical, where kinetic energy is transferred through direct contact from an impacting body or a vibrating surface, and aerodynamic, where dust particles are resuspended by the flow disturbance generated by the body. In this presentation we focus on aerodynamic resuspension of particles caused by walking. The foot movement is idealized and is either towards or away from a floor without touching it. As a first approach, a 15 cm diameter disk having the equivalent area to that of a human foot is used. The ``foot'' movement is driven vertically by a linear servo motor that controls the velocity, acceleration, stroke and deceleration (a typical vertical velocity is 0.5-1.0 m/s). A thin layer of dust is spread on a table relative to which the disk is allowed to move up and down. Flow visualizations show that both the upward and downward movements of the disk play an important role in the dust resuspension. A clear effect of radial jet and vortex dynamics on the particle resuspension is observed during the downward motion. In the wake of the rising disk, the particles were entrained upwards as a starting ring vortex formed. Quantitative PIV measurements will be performed to help further analyze the flow structure of this flow configuration.

  10. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  11. Ideal glass transitions by random pinning

    PubMed Central

    Cammarota, Chiara; Biroli, Giulio

    2012-01-01

    We study the effect of freezing the positions of a fraction c of particles from an equilibrium configuration of a supercooled liquid at a temperature T. We show that within the random first-order transition theory pinning particles leads to an ideal glass transition for a critical fraction c = cK(T) even for moderate supercooling; e.g., close to the Mode-Coupling transition temperature. First we derive the phase diagram in the T - c plane by mean field approximations. Then, by applying a real-space renormalization group method, we obtain the critical properties for |c - cK(T)| → 0, in particular the divergence of length and time scales, which are dominated by two zero-temperature fixed points. We also show that for c = cK(T) the typical distance between frozen particles is related to the static point-to-set length scale of the unconstrained liquid. We discuss what are the main differences when particles are frozen in other geometries and not from an equilibrium configuration. Finally, we explain why the glass transition induced by freezing particles provides a new and very promising avenue of research to probe the glassy state and ascertain, or disprove, the validity of the theories of the glass transition. PMID:22623524

  12. Photon statistics of atomic fluorescence after {pi}-pulse excitation

    SciTech Connect

    Yoshimi, Kazuyoshi; Koshino, Kazuki

    2010-09-15

    The photon statistics of atomic fluorescence after {pi}-pulse excitation is investigated in a system in which the input and output ports are connected to an atom. Since spontaneous decay during input pulse excitation occurs, the output pulse generally contains a multiphoton component with a certain probability. We quantitatively evaluate the probability of the output pulse containing multiple photons and determine the conditions for ideal single-photon generation.

  13. Atomic Interferometry with Detuned Counter-Propagating Electromagnetic Pulses

    SciTech Connect

    Tsang, Ming -Yee

    2014-09-05

    Atomic fountain interferometry uses atoms cooled with optical molasses to 1 μK, which are then launched in a fountain mode. The interferometer relies on the nonlinear Raman interaction of counter-propagating visible light pulses. We present models of these key transitions through a series of Hamiltonians. Our models, which have been verified against special cases with known solutions, allow us to incorporate the effects of non-ideal pulse shapes and realistic laser frequency or wavevector jitter.

  14. Field topologies in ideal and near-ideal magnetohydrodynamics and vortex dynamics

    NASA Astrophysics Data System (ADS)

    Low, B. C.

    2015-01-01

    Magnetic field topology frozen in ideal magnetohydrodynamics (MHD) and its breakage in near-ideal MHD are reviewed in two parts, clarifying and expanding basic concepts. The first part gives a physically complete description of the frozen field topology derived from magnetic flux conservation as the fundamental property, treating four conceptually related topics: Eulerian and Lagrangian descriptions of three dimensional (3D) MHD, Chandrasekhar-Kendall and Euler-potential field representations, magnetic helicity, and inviscid vortex dynamics as a fluid system in physical contrast to ideal MHD. A corollary of these developments clarifies the challenge of achieving a high degree of the frozen-in condition in numerical MHD. The second part treats field-topology breakage centered around the Parker Magnetostatic Theorem on a general incompatibility of a continuous magnetic field with the dual demand of force-free equilibrium and an arbitrarily prescribed, 3D field topology. Preserving field topology as a global constraint readily results in formation of tangential magnetic discontinuities, or, equivalently, electric current-sheets of zero thickness. A similar incompatibility is present in the steady force-thermal balance of a heated radiating fluid subject to an anisotropic thermal flux conducted strictly along its frozen-in magnetic field in the low- β limit. In a weakly resistive fluid the thinning of current sheets by these general incompatibilities inevitably results in sheet dissipation, resistive heating and topological changes in the field notwithstanding the small resistivity. Strong Faraday induction drives but also macroscopically limits this mode of energy dissipation, trapping or storing free energy in self-organized ideal-MHD structures. This property of MHD turbulence captured by the Taylor hypothesis is reviewed in relation to the Sun's corona, calling for a basic quantitative description of the breakdown of flux conservation in the low-resistivity limit

  15. Nonlinear filtering and limiting in high order methods for ideal and non-ideal MHD

    NASA Technical Reports Server (NTRS)

    Yee,H. C.; Sjogreen, B.

    2004-01-01

    The various filtering mechanisms and base scheme options of the newly developed adaptive numerical dissipation control in spatially high order filter schemes for the ideal and non-ideal magnetohydrodynamics (MHD) equations are investigated. These filter schemes are applicable to complex unsteady MHD high-speed shock/shear/turbulence problems. They also provide a natural and efficient way for the minimization of Div(B) numerical error. The type of spatial base scheme to be used in conjunction with our filter idea is very general. For example, spectral, compact and non-compact spatially central finite difference schemes are possible candidates. The adaptive numerical dissipation mechanism consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and to leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is also very general. The objective of this paper is to investigate the performance of using compact and non-compact central base schemes in conjunction with three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD. This extended abstract shows the performance of three nonlinear filters in conjunction with a sixth-order non-compact spatial central base scheme. In the final paper, the high order compact spatial central base scheme will be illustrated and compared with the non-compact base scheme. The reason for the investigation of the high order compact spatial central base scheme over the non-compact base scheme is to evaluate if additional accuracy can be gained in regions of

  16. Nonlinear filtering and limiting in high order methods for ideal and non-ideal MHD

    NASA Technical Reports Server (NTRS)

    Yee,H. C.; Sjogreen, B.

    2004-01-01

    The various filtering mechanisms and base scheme options of the newly developed adaptive numerical dissipation control in spatially high order filter schemes for the ideal and non-ideal magnetohydrodynamics (MHD) equations are investigated. These filter schemes are applicable to complex unsteady MHD high-speed shock/shear/turbulence problems. They also provide a natural and efficient way for the minimization of Div(B) numerical error. The type of spatial base scheme to be used in conjunction with our filter idea is very general. For example, spectral, compact and non-compact spatially central finite difference schemes are possible candidates. The adaptive numerical dissipation mechanism consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and to leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is also very general. The objective of this paper is to investigate the performance of using compact and non-compact central base schemes in conjunction with three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD. This extended abstract shows the performance of three nonlinear filters in conjunction with a sixth-order non-compact spatial central base scheme. In the final paper, the high order compact spatial central base scheme will be illustrated and compared with the non-compact base scheme. The reason for the investigation of the high order compact spatial central base scheme over the non-compact base scheme is to evaluate if additional accuracy can be gained in regions of

  17. Athletic-ideal and thin-ideal internalization as prospective predictors of body dissatisfaction, dieting, and compulsive exercise.

    PubMed

    Homan, Kristin

    2010-06-01

    Although internalization of the thin ideal has been extensively researched and is now regarded as a risk factor for eating disturbance, endorsement of the firm, athletic body ideal has received only minimal attention. This short-term longitudinal study explored whether internalization of two aspects of the current cultural ideal (thinness and athleticism) prospectively predicted three potentially deleterious outcomes: body dissatisfaction, dieting, and compulsive exercise. Undergraduate women (N=231) completed self-report measures at the beginning of the academic year and again 7 months later (N=156 at Time 2). Athletic-ideal internalization predicted change in compulsive exercise over the 7-month study period but not body dissatisfaction or dieting; thin-ideal internalization predicted change in all three outcomes. When both internalization measures were tested simultaneously, neither contributed unique variance. Results suggest that athletic-ideal internalization is not as detrimental as thin-ideal internalization.

  18. Family Life and Developmental Idealism in Yazd, Iran

    PubMed Central

    Abbasi-Shavazi, Mohammad Jalal; Askari-Nodoushan, Abbas

    2012-01-01

    BACKGROUND This paper is motivated by the theory that developmental idealism has been disseminated globally and has become an international force for family and demographic change. Developmental idealism is a set of cultural beliefs and values about development and how development relates to family and demographic behavior. It holds that modern societies are causal forces producing modern families, that modern families help to produce modern societies, and that modern family change is to be expected. OBJECTIVE We examine the extent to which developmental idealism has been disseminated in Iran. We also investigate predictors of the dissemination of developmental idealism. METHODS We use survey data collected in 2007 from a sample of women in Yazd, a city in Iran. We examine the distribution of developmental idealism in the sample and the multivariate predictors of developmental idealism. RESULTS We find considerable support for the expectation that many elements of developmental idealism have been widely disseminated. Statistically significant majorities associate development with particular family attributes, believe that development causes change in families, believe that fertility reductions and age-at-marriage increases help foster development, and perceive family trends in Iran headed toward modernity. As predicted, parental education, respondent education, and income affect adherence to developmental idealism. CONCLUSIONS Developmental idealism has been widely disseminated in Yazd, Iran and is related to social and demographic factors in predicted ways. COMMENTS Although our data come from only one city, we expect that developmental idealism has been widely distributed in Iran, with important implications for family and demographic behavior. PMID:22942772

  19. Family Life and Developmental Idealism in Yazd, Iran.

    PubMed

    Abbasi-Shavazi, Mohammad Jalal; Askari-Nodoushan, Abbas

    2012-01-01

    BACKGROUND: This paper is motivated by the theory that developmental idealism has been disseminated globally and has become an international force for family and demographic change. Developmental idealism is a set of cultural beliefs and values about development and how development relates to family and demographic behavior. It holds that modern societies are causal forces producing modern families, that modern families help to produce modern societies, and that modern family change is to be expected. OBJECTIVE: We examine the extent to which developmental idealism has been disseminated in Iran. We also investigate predictors of the dissemination of developmental idealism. METHODS: We use survey data collected in 2007 from a sample of women in Yazd, a city in Iran. We examine the distribution of developmental idealism in the sample and the multivariate predictors of developmental idealism. RESULTS: We find considerable support for the expectation that many elements of developmental idealism have been widely disseminated. Statistically significant majorities associate development with particular family attributes, believe that development causes change in families, believe that fertility reductions and age-at-marriage increases help foster development, and perceive family trends in Iran headed toward modernity. As predicted, parental education, respondent education, and income affect adherence to developmental idealism. CONCLUSIONS: Developmental idealism has been widely disseminated in Yazd, Iran and is related to social and demographic factors in predicted ways. COMMENTS: Although our data come from only one city, we expect that developmental idealism has been widely distributed in Iran, with important implications for family and demographic behavior.

  20. Big Surveys, Big Data Centres

    NASA Astrophysics Data System (ADS)

    Schade, D.

    2016-06-01

    Well-designed astronomical surveys are powerful and have consistently been keystones of scientific progress. The Byurakan Surveys using a Schmidt telescope with an objective prism produced a list of about 3000 UV-excess Markarian galaxies but these objects have stimulated an enormous amount of further study and appear in over 16,000 publications. The CFHT Legacy Surveys used a wide-field imager to cover thousands of square degrees and those surveys are mentioned in over 1100 publications since 2002. Both ground and space-based astronomy have been increasing their investments in survey work. Survey instrumentation strives toward fair samples and large sky coverage and therefore strives to produce massive datasets. Thus we are faced with the "big data" problem in astronomy. Survey datasets require specialized approaches to data management. Big data places additional challenging requirements for data management. If the term "big data" is defined as data collections that are too large to move then there are profound implications for the infrastructure that supports big data science. The current model of data centres is obsolete. In the era of big data the central problem is how to create architectures that effectively manage the relationship between data collections, networks, processing capabilities, and software, given the science requirements of the projects that need to be executed. A stand alone data silo cannot support big data science. I'll describe the current efforts of the Canadian community to deal with this situation and our successes and failures. I'll talk about how we are planning in the next decade to try to create a workable and adaptable solution to support big data science.

  1. The Canadian Astronomy Data Centre

    NASA Astrophysics Data System (ADS)

    Ball, Nicholas M.; Schade, D.; Astronomy Data Centre, Canadian

    2011-01-01

    The Canadian Astronomy Data Centre (CADC) is the world's largest astronomical data center, holding over 0.5 Petabytes of information, and serving nearly 3000 astronomers worldwide. Its current data collections include BLAST, CFHT, CGPS, FUSE, Gemini, HST, JCMT, MACHO, MOST, and numerous other archives and services. It provides extensive data archiving, curation, and processing expertise, via projects such as MegaPipe, and enables substantial day-to-day collaboration between resident astronomers and computer specialists. It is a stable, powerful, persistent, and properly supported environment for the storage and processing of large volumes of data, a condition that is now absolutely vital for their science potential to be exploited by the community. Through initiatives such as the Common Archive Observation Model (CAOM), the Canadian Virtual Observatory (CVO), and the Canadian Advanced Network for Astronomical Research (CANFAR), the CADC is at the global forefront of advancing astronomical research through improved data services. The CAOM aims to provide homogeneous data access, and hence viable interoperability between a potentially unlimited number of different data collections, at many wavelengths. It is active in the definition of numerous emerging standards within the International Virtual Observatory, and several datasets are already available. The CANFAR project is an initiative to make cloud computing for storage and data-intensive processing available to the community. It does this via a Virtual Machine environment that is equivalent to managing a local desktop. Several groups are already processing science data. CADC is also at the forefront of advanced astronomical data analysis, driven by the science requirements of astronomers both locally and further afield. The emergence of 'Astroinformatics' promises to provide not only utility items like object classifications, but to directly enable new science by accessing previously undiscovered or intractable

  2. Studying of barrier height and ideality factor relation in the nano sized Au-n type Si Schottky diodes

    NASA Astrophysics Data System (ADS)

    Yeganeh, M. A.; Mamedov, R. K.; Rahmatallahpur, Sh.

    2011-07-01

    The results of formation of the operating potential barrier height ( Φв) of inhomogeneous Schottky diodes (SD) in view of an additional electric field in the near contact region of the semiconductor and features of its dependence on the external applied voltage are presented. A correlation, between SD heterogeneity and dependence between potential barrier height ( Φв) and ideality factor ( n), is presented. Using conducting probe atomic force microscope (CP-AFM) techniques, it is shown that Au/n-Si diodes consist of sets of parallel-connected and cooperating nano diodes with the contact surfaces sizes in the order of 100-200 nm. The effective Φв and ideality factors of the SD have been obtained from the current-voltage ( I- V) characteristics, which were measured using a CP-AFM along a contact surface. It was experimentally shown that the forward and reverse part of I- V characteristics and their effective Φв and ideality factors of the identically fabricated nano-SD differ from diode to diode. The Φв for the nano-SD has ranged from 0.565 to 0.723 eV and ideality factor from 1.11 to 1.98. No correlation can be found between the Φв and ideality factor. The Φв distribution obtained from the I- V characteristics has been fitted by a Gaussian function but the ideality factor distribution could not be fitted by a Gaussian function.

  3. Extending cluster description to bimetallic nanowires: The ideal solid solution alloy case

    NASA Astrophysics Data System (ADS)

    Maras, E.; Braems, I.; Berthier, F.

    2011-12-01

    We present a comprehensive study of the equilibrium properties of two codeposited species for an alloy that forms an ideal solution, on a one-dimensional chain. By use of a cluster description we provide exact formulae of the coverages, the total density of clusters, the cluster size distribution, and the chemical composition of each cluster. These analytical results, that are proved to be in agreement with Monte Carlo simulations, strongly differ from the ones derived in the mean-field framework. Indeed, we show by depicting the codeposit at the macroscopic, mesoscopic, and atomic scales, that its features are to be related to the chemical heterogeneities at the edges of the clusters.

  4. Ideal superspin glass behaviour in a random-close-packed ensemble of maghemite nanoparticles

    NASA Astrophysics Data System (ADS)

    De Toro, J. A.; Lee, S. S.; Mathieu, R.; Normile, P. S.; Salazar, D.; Cheong, J. L.; Muñiz, P.; Riveiro, J. M.; Hillenkamp, M.; Tamion, A.; Tournus, F.; Nordblad, P.

    2014-06-01

    Highly uniform (8 nm) bare maghemite nanoparticles were pressed into a disc with a volume fraction close to the characteristic filling factor of random-close-packed ensembles of spherical particles. We review the ideal superspin glass behaviour exhibited by this material, including an onset of the absorption component of the ac susceptibility at the freezing transition as sharp (in a normalized temperature scale) as those observed in atomic spin glasses, narrow memory dips in the zero-field cooled magnetization, and a spin-glass characteristic field-dependence of the susceptibility. Critical exponents were extracted from static and dynamic scaling analysis.

  5. Ultracold atoms and precise time standards.

    PubMed

    Campbell, Gretchen K; Phillips, William D

    2011-10-28

    Experimental techniques of laser cooling and trapping, along with other cooling techniques, have produced gaseous samples of atoms so cold that they are, for many practical purposes, in the quantum ground state of their centre-of-mass motion. Such low velocities have virtually eliminated effects such as Doppler shifts, relativistic time dilation and observation-time broadening that previously limited the performance of atomic frequency standards. Today, the best laser-cooled, caesium atomic fountain, microwave frequency standards realize the International System of Units (SI) definition of the second to a relative accuracy of ≈3×10(-16). Optical frequency standards, which do not realize the SI second, have even better performance: cold neutral atoms trapped in optical lattices now yield relative systematic uncertainties of ≈1×10(-16), whereas cold-trapped ions have systematic uncertainties of 9×10(-18). We will discuss the current limitations in the performance of neutral atom atomic frequency standards and prospects for the future.

  6. GCSS Idealized Cirrus Model Comparison Project

    NASA Technical Reports Server (NTRS)

    Starr, David OC.; Benedetti, Angela; Boehm, Matt; Brown, Philip R. A.; Gierens, Klaus; Girard, Eric; Giraud, Vincent; Jakob, Christian; Jensen, Eric; Khvorostyanov, Vitaly; hide

    2000-01-01

    The GCSS Working Group on Cirrus Cloud Systems (WG2) is conducting a systematic comparison and evaluation of cirrus cloud models. This fundamental activity seeks to support the improvement of models used for climate simulation and numerical weather prediction through assessment and improvement of the "process" models underlying parametric treatments of cirrus cloud processes in large-scale models. The WG2 Idealized Cirrus Model Comparison Project is an initial comparison of cirrus cloud simulations by a variety of cloud models for a series of idealized situations with relatively simple initial conditions and forcing. The models (16) represent the state-of-the-art and include 3-dimensional large eddy simulation (LES) models, two-dimensional cloud resolving models (CRMs), and single column model (SCM) versions of GCMs. The model microphysical components are similarly varied, ranging from single-moment bulk (relative humidity) schemes to fully size-resolved (bin) treatments where ice crystal growth is explicitly calculated. Radiative processes are included in the physics package of each model. The baseline simulations include "warm" and "cold" cirrus cases where cloud top initially occurs at about -47C and -66C, respectively. All simulations are for nighttime conditions (no solar radiation) where the cloud is generated in an ice supersaturated layer, about 1 km in depth, with an ice pseudoadiabatic thermal stratification (neutral). Continuing cloud formation is forced via an imposed diabatic cooling representing a 3 cm/s uplift over a 4-hour time span followed by a 2-hour dissipation stage with no cooling. Variations of these baseline cases include no-radiation and stable-thermal-stratification cases. Preliminary results indicated the great importance of ice crystal fallout in determining even the gross cloud characteristics, such as average vertically-integrated ice water path (IWP). Significant inter-model differences were found. Ice water fall speed is directly

  7. GCSS Idealized Cirrus Model Comparison Project

    NASA Technical Reports Server (NTRS)

    Starr, David OC.; Benedetti, Angela; Boehm, Matt; Brown, Philip R. A.; Gierens, Klaus; Girard, Eric; Giraud, Vincent; Jakob, Christian; Jensen, Eric; Khvorostyanov, Vitaly; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The GCSS Working Group on Cirrus Cloud Systems (WG2) is conducting a systematic comparison and evaluation of cirrus cloud models. This fundamental activity seeks to support the improvement of models used for climate simulation and numerical weather prediction through assessment and improvement of the "process" models underlying parametric treatments of cirrus cloud processes in large-scale models. The WG2 Idealized Cirrus Model Comparison Project is an initial comparison of cirrus cloud simulations by a variety of cloud models for a series of idealized situations with relatively simple initial conditions and forcing. The models (16) represent the state-of-the-art and include 3-dimensional large eddy simulation (LES) models, two-dimensional cloud resolving models (CRMs), and single column model (SCM) versions of GCMs. The model microphysical components are similarly varied, ranging from single-moment bulk (relative humidity) schemes to fully size-resolved (bin) treatments where ice crystal growth is explicitly calculated. Radiative processes are included in the physics package of each model. The baseline simulations include "warm" and "cold" cirrus cases where cloud top initially occurs at about -47C and -66C, respectively. All simulations are for nighttime conditions (no solar radiation) where the cloud is generated in an ice supersaturated layer, about 1 km in depth, with an ice pseudoadiabatic thermal stratification (neutral). Continuing cloud formation is forced via an imposed diabatic cooling representing a 3 cm/s uplift over a 4-hour time span followed by a 2-hour dissipation stage with no cooling. Variations of these baseline cases include no-radiation and stable-thermal-stratification cases. Preliminary results indicated the great importance of ice crystal fallout in determining even the gross cloud characteristics, such as average vertically-integrated ice water path (IWP). Significant inter-model differences were found. Ice water fall speed is directly

  8. Exotic Atoms and Muonium

    NASA Astrophysics Data System (ADS)

    Horváth, D.

    In exotic atoms, one of the atomic electrons is replaced by a negatively charged particle, whereas muonium consists of a positive muon and an electron. After a general review of the theoretical and experimental aspects, the present knowledge of this field is summarized. These include muonium and the application of the muon spin resonance method in solid-state physics and chemistry, muonic hydrogen atoms, muonic molecules and muon-catalyzed fusion, pionic hydrogen atoms and their use in chemistry, testing quantum electrodynamics on heavy muonic atoms, measuring particle and nuclear properties using hadronic atoms, and testing basic symmetry principles with antiprotonic helium atoms and antihydrogen.

  9. Idealized Computational Models for Auditory Receptive Fields

    PubMed Central

    Lindeberg, Tony; Friberg, Anders

    2015-01-01

    We present a theory by which idealized models of auditory receptive fields can be derived in a principled axiomatic manner, from a set of structural properties to (i) enable invariance of receptive field responses under natural sound transformations and (ii) ensure internal consistency between spectro-temporal receptive fields at different temporal and spectral scales. For defining a time-frequency transformation of a purely temporal sound signal, it is shown that the framework allows for a new way of deriving the Gabor and Gammatone filters as well as a novel family of generalized Gammatone filters, with additional degrees of freedom to obtain different trade-offs between the spectral selectivity and the temporal delay of time-causal temporal window functions. When applied to the definition of a second-layer of receptive fields from a spectrogram, it is shown that the framework leads to two canonical families of spectro-temporal receptive fields, in terms of spectro-temporal derivatives of either spectro-temporal Gaussian kernels for non-causal time or a cascade of time-causal first-order integrators over the temporal domain and a Gaussian filter over the logspectral domain. For each filter family, the spectro-temporal receptive fields can be either separable over the time-frequency domain or be adapted to local glissando transformations that represent variations in logarithmic frequencies over time. Within each domain of either non-causal or time-causal time, these receptive field families are derived by uniqueness from the assumptions. It is demonstrated how the presented framework allows for computation of basic auditory features for audio processing and that it leads to predictions about auditory receptive fields with good qualitative similarity to biological receptive fields measured in the inferior colliculus (ICC) and primary auditory cortex (A1) of mammals. PMID:25822973

  10. Idealized computational models for auditory receptive fields.

    PubMed

    Lindeberg, Tony; Friberg, Anders

    2015-01-01

    We present a theory by which idealized models of auditory receptive fields can be derived in a principled axiomatic manner, from a set of structural properties to (i) enable invariance of receptive field responses under natural sound transformations and (ii) ensure internal consistency between spectro-temporal receptive fields at different temporal and spectral scales. For defining a time-frequency transformation of a purely temporal sound signal, it is shown that the framework allows for a new way of deriving the Gabor and Gammatone filters as well as a novel family of generalized Gammatone filters, with additional degrees of freedom to obtain different trade-offs between the spectral selectivity and the temporal delay of time-causal temporal window functions. When applied to the definition of a second-layer of receptive fields from a spectrogram, it is shown that the framework leads to two canonical families of spectro-temporal receptive fields, in terms of spectro-temporal derivatives of either spectro-temporal Gaussian kernels for non-causal time or a cascade of time-causal first-order integrators over the temporal domain and a Gaussian filter over the logspectral domain. For each filter family, the spectro-temporal receptive fields can be either separable over the time-frequency domain or be adapted to local glissando transformations that represent variations in logarithmic frequencies over time. Within each domain of either non-causal or time-causal time, these receptive field families are derived by uniqueness from the assumptions. It is demonstrated how the presented framework allows for computation of basic auditory features for audio processing and that it leads to predictions about auditory receptive fields with good qualitative similarity to biological receptive fields measured in the inferior colliculus (ICC) and primary auditory cortex (A1) of mammals.

  11. Variational Perturbation Treatment of the Confined Hydrogen Atom

    ERIC Educational Resources Information Center

    Montgomery, H. E., Jr.

    2011-01-01

    The Schrodinger equation for the ground state of a hydrogen atom confined at the centre of an impenetrable cavity is treated using variational perturbation theory. Energies calculated from variational perturbation theory are comparable in accuracy to the results from a direct numerical solution. The goal of this exercise is to introduce the…

  12. Variational Perturbation Treatment of the Confined Hydrogen Atom

    ERIC Educational Resources Information Center

    Montgomery, H. E., Jr.

    2011-01-01

    The Schrodinger equation for the ground state of a hydrogen atom confined at the centre of an impenetrable cavity is treated using variational perturbation theory. Energies calculated from variational perturbation theory are comparable in accuracy to the results from a direct numerical solution. The goal of this exercise is to introduce the…

  13. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  14. High Atom Number in Microsized Atom Traps

    DTIC Science & Technology

    2015-12-14

    2012 conference of the Division of Atomic , Molecular, and Optical Physics (DAMOP) of the American Physical Society (APS). We have reconfigured the...Final Performance Report on ONR Grant N00014-12-1-0608 High atom number in microsized atom traps for the period 15 May 2012 through 14 September...2015 J. M. Grossman Department of Physics St. Mary’s College of Maryland 18952 E. Fisher Road St. Mary’s City, MD 20686 jmgrossman @smcm. edu

  15. Effective distribution coefficients of a binary ideal solid solution controlled by kink kinetics

    NASA Astrophysics Data System (ADS)

    Matsumoto, Naoko; Kitamura, Masao

    2001-01-01

    Effective distribution coefficients of a binary ideal solid solution growing from dilute surroundings are derived for the steady state using a model in which atoms attach and detach only at kink sites on a (0 0 1) surface of a simple cubic crystal. A system of equations is presented to give the step-edge, terrace, and bulk compositions in terms of attachment and detachment frequencies. The total net flux of atoms from the mother phase to kink sites is also formulated as a function of these compositions and the frequencies. Numerical solutions to the system of equations show that the step-edge, terrace, and bulk compositions are different from one another and that the step-edge, terrace, and bulk distribution coefficients will all approach unity from their respective equilibrium values as the total net flux increases.

  16. Review of CERN Data Centre Infrastructure

    NASA Astrophysics Data System (ADS)

    Andrade, P.; Bell, T.; van Eldik, J.; McCance, G.; Panzer-Steindel, B.; Coelho dos Santos, M.; Traylen and, S.; Schwickerath, U.

    2012-12-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project's motivations, current status and areas for future investigation.

  17. Towards Human-Centred Design

    NASA Astrophysics Data System (ADS)

    Bannon, Liam J.

    The field of HCI has evolved and expanded dramatically since its origin in the early 1980’s. The HCI community embraces a large community of researchers and practitioners around the world, from a variety of disciplinary backgrounds in the human and social sciences, engineering and informatics, and more recently, the arts and design disciplines. This kaleidoscope of cultures and disciplines as seen at INTERACT Conferences provides a rich pool of resources for examining our field. Applications are increasingly exploring our full range of sensory modalities, and merging the digital and physical worlds. WiFi has opened up a huge design space for mobile applications. A focus on usability of products and services has been complemented by an emphasis on engagement, enjoyment and experience. With the advent of ubiquitous computing, and the emergence of “The Internet of Things”, new kinds of more open infrastructures make possible radically new kinds of applications. The sources of innovation have also broadened, to include human and social actors outside of the computing and design organizations. The question is to what extent is our mainstream thinking in the HCI field ready for the challenges of this Brave New World? Do the technological and social innovations that we see emerging require us to re-shape, or even, re-create, our field, or is it a case of a more gradual evolution and development of that which we already know? In this closing Keynote, I will provide a perspective on the evolution and development of the HCI field, looking backwards as well as forwards, in order to determine what are some of the changes of significance in the field. This “broad-brush” approach to what I term “ human-centred design” will be complemented by the examination of specific projects and applications, to help anchor some of the discussion. Areas such as user-centred design, participatory design, computer-supported cooperative work and learning, and interaction design, in

  18. Translating ubuntu to Spanish: Convivencia as a framework for re-centring education as a moral enterprise

    NASA Astrophysics Data System (ADS)

    Luschei, Thomas F.

    2016-02-01

    In this essay, the author introduces the concept of " convivencia" (peaceful coexistence) as a framework for re-centring education as a moral enterprise. He discusses convivencia within the context of education and society in Colombia, paying special attention to the Colombian rural school model Escuela Nueva (New School). This discussion draws on both previous evidence and the author's own research on the implementation of the Escuela Nueva model in urban areas of Colombia. He discusses several facets of convivencia and parallels with the ideas and ideals of ubuntu. Using convivencia as an organising principle, he presents insights for educational practitioners and researchers related to re-centring education as a moral enterprise.

  19. Engineering the Ideal Gigapixel Image Viewer

    NASA Astrophysics Data System (ADS)

    Perpeet, D. Wassenberg, J.

    2011-09-01

    Despite improvements in automatic processing, analysts are still faced with the task of evaluating gigapixel-scale mosaics or images acquired by telescopes such as Pan-STARRS. Displaying such images in ‘ideal’ form is a major challenge even today, and the amount of data will only increase as sensor resolutions improve. In our opinion, the ideal viewer has several key characteristics. Lossless display - down to individual pixels - ensures all information can be extracted from the image. Support for all relevant pixel formats (integer or floating point) allows displaying data from different sensors. Smooth zooming and panning in the high-resolution data enables rapid screening and navigation in the image. High responsiveness to input commands avoids frustrating delays. Instantaneous image enhancement, e.g. contrast adjustment and image channel selection, helps with analysis tasks. Modest system requirements allow viewing on regular workstation computers or even laptops. To the best of our knowledge, no such software product is currently available. Meeting these goals requires addressing certain realities of current computer architectures. GPU hardware accelerates rendering and allows smooth zooming without high CPU load. Programmable GPU shaders enable instant channel selection and contrast adjustment without any perceptible slowdown or changes to the input data. Relatively low disk transfer speeds suggest the use of compression to decrease the amount of data to transfer. Asynchronous I/O allows decompressing while waiting for previous I/O operations to complete. The slow seek times of magnetic disks motivate optimizing the order of the data on disk. Vectorization and parallelization allow significant increases in computational capacity. Limited memory requires streaming and caching of image regions. We develop a viewer that takes the above issues into account. Its awareness of the computer architecture enables previously unattainable features such as smooth

  20. Converging cylindrical shocks in ideal magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=sqrt{μ _0/p_0} I/(2 π ) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field

  1. Converging cylindrical shocks in ideal magnetohydrodynamics

    SciTech Connect

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-09-15

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ{sub 0}/p{sub 0}) I/(2 π) where I is the current, μ{sub 0} is the permeability, and p{sub 0} is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The

  2. Ideal cardiovascular health and incident hypertension

    PubMed Central

    Zhao, Hai Yan; Liu, Xiao Xue; Wang, An Xin; Wu, Yun Tao; Zheng, Xiao Ming; Zhao, Xiao Hong; Cui, Kai; Ruan, Chun Yu; Lu, Cheng Zhi; Jonas, Jost B.; Wu, Shou Ling

    2016-01-01

    Abstract Ideal cardiovascular health (CVH) has been defined by the American Heart Association as the absence of disease and presence of 7 key health factors. Since it is unknown whether cumulative exposure to CVH reduces the risk of developing arterial hypertension, we prospectively examined the potential association between cumulative CVH (cumCVH) score (except for blood pressure metrics) and incident hypertension. Of the 101,510 participants with an age range of 18 to 98 years in this longitudinal community-based Kailuan study, our cohort included those 15,014 participants without hypertension at baseline and who had follow-up examinations 2, 4, and 6 years later. CumCVH was calculated as the summed CVH score for each examination multiplied by the time between the 2 examinations (points × year). Based on the cumCVH score, the study population was stratified into groups of <44 points, 44 to 48 points, 49 to 54 points, 55 to 59 points, and ≥60 points. Incidence of hypertension ranged from 16.76% in the lowest cumCVH category to 11.52% in the highest cumCVH category. After adjusting for age, sex, education level, income level, high-sensitivity C-reactive protein concentration, uric acid concentration, resting heart rate, parental history of hypertension at baseline, and medication usage before the third follow-up examination, participants in the highest cumCVH category had a significantly reduced risk of incident hypertension compared with those in the lowest cumCVH category (adjusted odds ratio 0.60, 95% confidence interval 0.50–0.71). For every increase in category based on the cumCVH score, the risk of hypertension decreased by approximately 2% (odds ratio 0.98, 95% confidence interval 0.97–0.98). The effect was consistent across sex and age groups. A higher cumCVH score is associated with a lower risk of incident hypertension. PMID:27977580

  3. Atomic-scale sensing of the magnetic dipolar field from single atoms.

    PubMed

    Choi, Taeyoung; Paul, William; Rolf-Pissarczyk, Steffen; Macdonald, Andrew J; Natterer, Fabian D; Yang, Kai; Willke, Philip; Lutz, Christopher P; Heinrich, Andreas J

    2017-05-01

    Spin resonance provides the high-energy resolution needed to determine biological and material structures by sensing weak magnetic interactions. In recent years, there have been notable achievements in detecting and coherently controlling individual atomic-scale spin centres for sensitive local magnetometry. However, positioning the spin sensor and characterizing spin-spin interactions with sub-nanometre precision have remained outstanding challenges. Here, we use individual Fe atoms as an electron spin resonance (ESR) sensor in a scanning tunnelling microscope to measure the magnetic field emanating from nearby spins with atomic-scale precision. On artificially built assemblies of magnetic atoms (Fe and Co) on a magnesium oxide surface, we measure that the interaction energy between the ESR sensor and an adatom shows an inverse-cube distance dependence (r(-3.01±0.04)). This demonstrates that the atoms are predominantly coupled by the magnetic dipole-dipole interaction, which, according to our observations, dominates for atom separations greater than 1 nm. This dipolar sensor can determine the magnetic moments of individual adatoms with high accuracy. The achieved atomic-scale spatial resolution in remote sensing of spins may ultimately allow the structural imaging of individual magnetic molecules, nanostructures and spin-labelled biomolecules.

  4. Atomic-scale sensing of the magnetic dipolar field from single atoms

    NASA Astrophysics Data System (ADS)

    Choi, Taeyoung; Paul, William; Rolf-Pissarczyk, Steffen; MacDonald, Andrew J.; Natterer, Fabian D.; Yang, Kai; Willke, Philip; Lutz, Christopher P.; Heinrich, Andreas J.

    2017-05-01

    Spin resonance provides the high-energy resolution needed to determine biological and material structures by sensing weak magnetic interactions. In recent years, there have been notable achievements in detecting and coherently controlling individual atomic-scale spin centres for sensitive local magnetometry. However, positioning the spin sensor and characterizing spin-spin interactions with sub-nanometre precision have remained outstanding challenges. Here, we use individual Fe atoms as an electron spin resonance (ESR) sensor in a scanning tunnelling microscope to measure the magnetic field emanating from nearby spins with atomic-scale precision. On artificially built assemblies of magnetic atoms (Fe and Co) on a magnesium oxide surface, we measure that the interaction energy between the ESR sensor and an adatom shows an inverse-cube distance dependence (r-3.01±0.04). This demonstrates that the atoms are predominantly coupled by the magnetic dipole-dipole interaction, which, according to our observations, dominates for atom separations greater than 1 nm. This dipolar sensor can determine the magnetic moments of individual adatoms with high accuracy. The achieved atomic-scale spatial resolution in remote sensing of spins may ultimately allow the structural imaging of individual magnetic molecules, nanostructures and spin-labelled biomolecules.

  5. Identity Theft: A Study in Contact Centres

    NASA Astrophysics Data System (ADS)

    Moir, Iain; Weir, George R. S.

    This paper explores the recent phenomenon of identity theft. In particular, it examines the contact centre environment as a mechanism for this to occur. Through a survey that was conducted amongst forty-five contact centre workers in the Glasgow area we determined that contact centres can and do provide a mechanism for identity theft. Specifically, we found a particularly high incidence of agents who had previously dealt with phone calls that they considered suspicious. Furthermore, there are agents within such environments who have previously been offered money in exchange for customers' details, or who know of fellow workers who received such offers. Lastly, we identify specific practices within contact centres that may contribute to the likelihood of identity theft.

  6. Enhanced Schwinger pair production in many-centre systems

    NASA Astrophysics Data System (ADS)

    Fillion-Gourdeau, François; Lorin, Emmanuel; Bandrauk, André D.

    2013-09-01

    Electron-positron pair production is considered for many-centre systems with multiple bare nuclei immersed in a constant electric field. It is shown that there are two distinct regimes where the pair production rate is enhanced. At small interatomic distance, the effective charge of the nuclei approaches the critical charge where the ground state dives into the negative continuum. This facilitates the transition from the negative to the positive energy states, which in turn increases the pair production rate. At larger atomic distance, the enhancement is due to the crossing of resonances and the pair production proceeds by the resonantly enhanced pair production mechanism. These processes are studied within a simple one-dimensional model. A numerical method is developed to evaluate the transmission coefficient in relativistic quantum mechanics, which is required in the calculation of the pair production rate. The latter is evaluated for systems with many (up to five) nuclei. It is shown that the production rate for many-centre systems can reach a few orders of magnitude above Schwinger’s tunnelling result in a static field.

  7. Colour centres and nanostructures on the surface of laser crystals

    NASA Astrophysics Data System (ADS)

    Kulagin, N. A.

    2012-11-01

    This paper presents a study of structural and radiationinduced colour centres in the bulk and ordered nanostructures on the surface of doped laser crystals: sapphire, yttrium aluminium garnet and strontium titanate. The influence of thermal annealing, ionising radiation and plasma exposure on the spectroscopic properties of high-purity materials and crystals containing Ti, V and Cr impurities is examined. Colour centres resulting from changes in the electronic state of impurities and plasma-induced surface modification of the crystals are studied by optical, EPR and X-ray spectroscopies, scanning electron microscopy and atomic force microscopy. X-ray line valence shift measurements are used to assess changes in the electronic state of some impurity and host ions in the bulk and on the surface of oxide crystals. Conditions are examined for the formation of one- and two-level arrays of ordered crystallites 10-10 to 10-7 m in size on the surface of crystals doped with irongroup and lanthanoid ions. The spectroscopic properties of the crystals are analysed using ab initio self-consistent field calculations for Men+ : [O2-]k clusters.

  8. Colour centres and nanostructures on the surface of laser crystals

    SciTech Connect

    Kulagin, N A

    2012-11-30

    This paper presents a study of structural and radiationinduced colour centres in the bulk and ordered nanostructures on the surface of doped laser crystals: sapphire, yttrium aluminium garnet and strontium titanate. The influence of thermal annealing, ionising radiation and plasma exposure on the spectroscopic properties of high-purity materials and crystals containing Ti, V and Cr impurities is examined. Colour centres resulting from changes in the electronic state of impurities and plasma-induced surface modification of the crystals are studied by optical, EPR and X-ray spectroscopies, scanning electron microscopy and atomic force microscopy. X-ray line valence shift measurements are used to assess changes in the electronic state of some impurity and host ions in the bulk and on the surface of oxide crystals. Conditions are examined for the formation of one- and two-level arrays of ordered crystallites 10{sup -10} to 10{sup -7} m in size on the surface of crystals doped with irongroup and lanthanoid ions. The spectroscopic properties of the crystals are analysed using ab initio self-consistent field calculations for Me{sup n+} : [O{sup 2-}]{sub k} clusters. (interaction of laser radiation with matter. laser plasma)

  9. Optically Controlled Distributed Quantum Computing Using Atomic Ensembles As Qubits

    DTIC Science & Technology

    2016-02-23

    alkali - metal atom such as 85Rb. After the π/2-dark- π/2 sequence, the system is in state |ψ〉 = WδT2π/2WδT20 WδT2π/2|1〉. Unlike in Sec. II, we here do...from a ytterbium fibre amplifier. 3. Rubidium quantum memory A neutral alkali atom held in a far-off-resonant trap (FORT) represents a potentially ideal...GEIT system using sublevels in alkali atoms such as Rb. However, current LIGO operates at the wavelength of FIG. 14 (color online). Schematic

  10. Atomic fluorescence study of high temperature aerodynamic levitation

    NASA Technical Reports Server (NTRS)

    Nordine, P. C.; Schiffman, R. A.; Sethi, D. S.

    1982-01-01

    Ultraviolet laser induced atomic fluorescence has been used to characterize supersonic jet aerodynamic levitation experiments. The levitated specimen was a 0.4 cm sapphire sphere that was separately heated at temperatures up to 2327 K by an infrared laser. The supersonic jet expansion and thermal gradients in the specimen wake were studied by measuring spatial variations in the concentration of atomic Hg added to the levitating argon gas stream. Further applications of atomic fluorescence in containerless experiments, such as ideal gas fluorescence thermometry and containerless process control are discussed.

  11. Atomic fluorescence study of high temperature aerodynamic levitation

    NASA Technical Reports Server (NTRS)

    Nordine, P. C.; Schiffman, R. A.; Sethi, D. S.

    1982-01-01

    Ultraviolet laser induced atomic fluorescence has been used to characterize supersonic jet aerodynamic levitation experiments. The levitated specimen was a 0.4 cm sapphire sphere that was separately heated at temperatures up to 2327 K by an infrared laser. The supersonic jet expansion and thermal gradients in the specimen wake were studied by measuring spatial variations in the concentration of atomic Hg added to the levitating argon gas stream. Further applications of atomic fluorescence in containerless experiments, such as ideal gas fluorescence thermometry and containerless process control are discussed.

  12. Slidable atomic layers in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yu; Taniguchi, Takashi; Watanabe, Kenji; Maniwa, Yutaka; Miyata, Yasumitsu

    2017-04-01

    We report the preparation and manipulation of slidable atomic layers in clean, incommensurate van der Waals (vdW) heterostructures. Monolayer and multilayer WS2 grains are grown on graphite and hexagonal boron nitride (hBN) via chemical vapor deposition, and these grains can slide smoothly on graphite and hBN surfaces by manipulation with a tip. Furthermore, this sliding process allows the suspension, tearing, stacking, and connection of the atomic layers. These results demonstrate a novel approach for developing a wide variety of atomic-layer heterostructures with tunable interlayer coupling and an ideal system for studying the superlubricity of incommensurate, highly clean vdW contacts.

  13. Quantum atom optics with fermions from molecular dissociation.

    PubMed

    Kheruntsyan, K V

    2006-03-24

    We study a fermionic atom optics counterpart of parametric down-conversion with photons. This can be realized through dissociation of a Bose-Einstein condensate of molecular dimers consisting of fermionic atoms. We present a theoretical model describing the quantum dynamics of dissociation and find analytic solutions for mode occupancies and atomic pair correlations, valid in the short time limit. The solutions are used to identify upper bounds for the correlation functions, which are applicable to any fermionic system and correspond to ideal particle number-difference squeezing.

  14. Atomic Fuel, Understanding the Atom Series. Revised.

    ERIC Educational Resources Information Center

    Hogerton, John F.

    This publication is part of the "Understanding the Atom" series. Complete sets of the series are available free to teachers, schools, and public librarians who can make them available for reference or use by groups. Among the topics discussed are: What Atomic Fuel Is; The Odyssey of Uranium; Production of Uranium; Fabrication of Reactor…

  15. Atomic Particle Detection, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Hellman, Hal

    This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. The instruments used to detect both particles and electromagnetic radiation that emerge from the nucleus are described. The counters reviewed include ionization chambers,…

  16. Perspectives on recycling centres and future developments.

    PubMed

    Engkvist, I-L; Eklund, J; Krook, J; Björkman, M; Sundin, E

    2016-11-01

    The overall aim of this paper is to draw combined, all-embracing conclusions based on a long-term multidisciplinary research programme on recycling centres in Sweden, focussing on working conditions, environment and system performance. A second aim is to give recommendations for their development of new and existing recycling centres and to discuss implications for the future design and organisation. Several opportunities for improvement of recycling centres were identified, such as design, layout, ease with which users could sort their waste, the work environment, conflicting needs and goals within the industry, and industrialisation. Combining all results from the research, which consisted of different disciplinary aspects, made it possible to analyse and elucidate their interrelations. Waste sorting quality was recognized as the most prominent improvement field in the recycling centre system. The research identified the importance of involving stakeholders with different perspectives when planning a recycling centre in order to get functionality and high performance. Practical proposals of how to plan and build recycling centres are given in a detailed checklist. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The Imperial College Thermophysical Properties Data Centre

    NASA Astrophysics Data System (ADS)

    Angus, S.; Cole, W. A.; Craven, R.; de Reuck, K. M.; Trengove, R. D.; Wakeham, W. A.

    1986-07-01

    The IUPAC Thermodynamic Tables Project Centre in London has at its disposal considerable expertise on the production and utilization of high-accuracy equations of state which represent the thermodynamic properties of substances. For some years they have been content to propagate this information by the traditional method of book production, but the increasing use of the computer in industry for process design has shown that an additional method was needed. The setting up of the IUPAC Transport Properties Project Centre, also at Imperial College, whose products would also be in demand by industry, afforded the occasion for a new look at the problem. The solution has been to set up the Imperial College Thermophysical Properties Data Centre, which embraces the two IUPAC Project Centres, and for it to establish a link with the existing Physical Properties Data Service of the Institution of Chemical Engineers, thus providing for the dissemination of the available information without involving the Centres in problems such as those of marketing and advertising. This paper outlines the activities of the Centres and discusses the problems in bringing their products to the attention of industry in suitable form.

  18. Quasideterministic generation of maximally entangled states of two mesoscopic atomic ensembles by adiabatic quantum feedback

    SciTech Connect

    Di Lisi, Antonio; De Siena, Silvio; Illuminati, Fabrizio; Vitali, David

    2005-09-15

    We introduce an efficient, quasideterministic scheme to generate maximally entangled states of two atomic ensembles. The scheme is based on quantum nondemolition measurements of total atomic populations and on adiabatic quantum feedback conditioned by the measurements outputs. The high efficiency of the scheme is tested and confirmed numerically for ideal photodetection as well as in the presence of losses.

  19. PHYSICS: Toward Atom Chips.

    PubMed

    Fortágh, József; Zimmermann, Claus

    2005-02-11

    As a novel approach for turning the peculiar features of quantum mechanics into practical devices, researchers are investigating the use of ultracold atomic clouds above microchips. Such "atom chips" may find use as sensitive probes for gravity, acceleration, rotation, and tiny magnetic forces. In their Perspective, Fortagh and Zimmermann discuss recent advances toward creating atom chips, in which current-carrying conductors in the chips create magnetic microtraps that confine the atomic clouds. Despite some intrinsic limits to the performance of atom chips, existing technologies are capable of producing atom chips, and many possibilities for their construction remain to be explored.

  20. Luminescence lifetimes of neutral nitrogen-vacancy centres in synthetic diamond containing nitrogen.

    PubMed

    Liaugaudas, G; Davies, G; Suhling, K; Khan, R U A; Evans, D J F

    2012-10-31

    The decay time of luminescence from neutral nitrogen-vacancy (NV(0)) centres in synthetic diamond is reported. The intrinsic luminescence lifetime of NV (0) is measured as τ(r) = 19 ± 2 ns. Neutral substitutional nitrogen atoms (N(S)(0)) are shown to quench luminescence from NV(0) by dipole-dipole resonant energy transfer at a rate such that the transfer time would equal τ(r) if one (N(S)(0)) atom was ~3 nm from the NV(0). In chemical-vapour-deposited diamonds grown with a small nitrogen content, that are brown as a result of vacancy-cluster defects, the decay time of NV(0) equals τ(r) in the as-grown material. However, after annealing at ≥1700 °C to remove the brown colour, luminescence from the NV(0) centres is severely quenched. This effect is suggested to be a result of the destruction of NV(0) centres and the creation of new NV(0) centres localized in vacancy-rich regions of the crystals.

  1. Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

    NASA Astrophysics Data System (ADS)

    González-Avilés, J. J.; Cruz-Osorio, A.; Lora-Clavijo, F. D.; Guzmán, F. S.

    2015-12-01

    We present a new code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centres on the analysis of solar phenomena within the photosphere-corona region. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As solar tests we present the transverse oscillations of Alfvénic pulses in coronal loops using a 2.5D model, and as 3D tests we present the propagation of impulsively generated MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the Harten-Lax-van Leer-Einfeldt (HLLE) flux formula combined with Minmod, MC, and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

  2. Heat dissipation in atomic-scale junctions.

    PubMed

    Lee, Woochul; Kim, Kyeongtae; Jeong, Wonho; Zotti, Linda Angela; Pauly, Fabian; Cuevas, Juan Carlos; Reddy, Pramod

    2013-06-13

    Atomic and single-molecule junctions represent the ultimate limit to the miniaturization of electrical circuits. They are also ideal platforms for testing quantum transport theories that are required to describe charge and energy transfer in novel functional nanometre-scale devices. Recent work has successfully probed electric and thermoelectric phenomena in atomic-scale junctions. However, heat dissipation and transport in atomic-scale devices remain poorly characterized owing to experimental challenges. Here we use custom-fabricated scanning probes with integrated nanoscale thermocouples to investigate heat dissipation in the electrodes of single-molecule ('molecular') junctions. We find that if the junctions have transmission characteristics that are strongly energy dependent, this heat dissipation is asymmetric--that is, unequal between the electrodes--and also dependent on both the bias polarity and the identity of the majority charge carriers (electrons versus holes). In contrast, junctions consisting of only a few gold atoms ('atomic junctions') whose transmission characteristics show weak energy dependence do not exhibit appreciable asymmetry. Our results unambiguously relate the electronic transmission characteristics of atomic-scale junctions to their heat dissipation properties, establishing a framework for understanding heat dissipation in a range of mesoscopic systems where transport is elastic--that is, without exchange of energy in the contact region. We anticipate that the techniques established here will enable the study of Peltier effects at the atomic scale, a field that has been barely explored experimentally despite interesting theoretical predictions. Furthermore, the experimental advances described here are also expected to enable the study of heat transport in atomic and molecular junctions--an important and challenging scientific and technological goal that has remained elusive.

  3. Evolutionary idealism: a philosophical foundation for holistic nursing theory.

    PubMed

    Sarter, B

    1987-01-01

    The philosophical tradition of evolutionary idealism is explored as an appropriate metaphysical foundation for holistic nursing science. Some implications of this tradition for theory development, testing, and practice are identified. It is suggested that evolutionary idealism can form an appropriate philosophical foundation for nursing theory development.

  4. Academic Deans' Perceptions of Current and Ideal Curriculum Emphases.

    ERIC Educational Resources Information Center

    Graber, David R.; O'Neil, Edward H.; Bellack, Janis P.; Musham, Catherine; Javed, Tariq

    1998-01-01

    A survey of 57 dental school deans concerning current and ideal curricular emphases in 33 topic areas identified three that were rated highly as ideals: health promotion/disease prevention; primary care; and effective patient-provider relationships/communication. The most significant barrier to reform was an already crowded curriculum. Deans…

  5. The Ideal Self and Cognitive Development in Adolescence

    ERIC Educational Resources Information Center

    Manaster, Guy J.; And Others

    1977-01-01

    Investigates the relationship between cognitive developmental level and the ideal self in adolescence, sampling 223 male and female 12- and 13-, and 15- and 16-year-old working and middle class English comprehensive school students, hypothesizing that maturity of the ideal self would be related to cognitive development. (Author/RK)

  6. Your Ideal Silhouette. Courseware Evaluation for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Tierney, Margaret S.; And Others

    This courseware evaluation rates the "Your Ideal Silhouette" program developed by Your Image, Inc. This program (not contained in this document) uses the computer to identify figure faults and illustrate personalized corrective style lines to achieve the ideal silhouette. Part A describes the program in terms of subject area (textiles…

  7. The "Ideal Teacher." Implications for Student Evaluation of Teacher Effectiveness.

    ERIC Educational Resources Information Center

    Pozo-Munoz, Carmen; Rebolloso-Pacheco, Enrique; Fernandez-Ramirez, Baltasar

    2000-01-01

    Examined characteristics defining the ideal teacher using the semantic differential (SD) scale, which can detect attributes of ideal teachers and find evaluative, emotional, or affective components linked to this concept. Spanish college students completed the SD Scale. Results found teacher profiles similar to those found using other assessments,…

  8. The "Ideal Professor" and Gender Effects in Christian Higher Education

    ERIC Educational Resources Information Center

    Woods, Robert H., Jr.; Badzinski, Diane M.; Fritz, Janie M. Harden; Yeates, Sarah E.

    2012-01-01

    A survey was administered to 451 undergraduate students at a private liberal arts Christian university to identify students' perceptions of the ideal professor. The survey revealed that the ideal professor places great emphasis on the integration of faith and learning, is flexible (and even easy), maintains high academic standards, encourages…

  9. The "Body Beautiful": English Adolescents' Images of Ideal Bodies.

    ERIC Educational Resources Information Center

    Dittmar, Helga; Lloyd, Barbara; Dugan, Shaun; Halliwell, Emma; Jacobs, Neil; Cramer, Helen

    2000-01-01

    Two studies examine qualities capturing adolescents' images of ideal bodies for both genders. Data from questionnaires and discussions of photographs indicate that body-image ideals are multidimensional, show systematic gender differences, and become more conventional with age. Adolescents' own body mass links systematically to body-image…

  10. What Do Doctoral Students Value in Their Ideal Mentor?

    ERIC Educational Resources Information Center

    Bell-Ellison, Bethany A.; Dedrick, Robert F.

    2008-01-01

    The purpose of this study was to contribute to the construct validity of the scores from Rose's (2003) 34-item "Ideal Mentor Scale" (IMS) and to examine whether male and female doctoral students value different attributes in their ideal mentor. Two hundred and twenty-four doctoral students from colleges (Education, Public Health, Nursing, Arts and…

  11. A Generalized Deduction of the Ideal-Solution Model

    ERIC Educational Resources Information Center

    Leo, Teresa J.; Perez-del-Notario, Pedro; Raso, Miguel A.

    2006-01-01

    A new general procedure for deriving the Gibbs energy of mixing is developed through general thermodynamic considerations, and the ideal-solution model is obtained as a special particular case of the general one. The deduction of the Gibbs energy of mixing for the ideal-solution model is a rational one and viewed suitable for advanced students who…

  12. A serial qualitative interview study of infant feeding experiences: idealism meets realism

    PubMed Central

    Craig, Leone C A; Britten, Jane; McInnes, Rhona M

    2012-01-01

    Objective To investigate the infant feeding experiences of women and their significant others from pregnancy until 6 months after birth to establish what would make a difference. Design Qualitative serial interview study. Setting Two health boards in Scotland. Participants 72 of 541 invited pregnant women volunteered. 220 interviews approximately every 4 weeks with 36 women, 26 partners, eight maternal mothers, one sister and two health professionals took place. Results The overarching theme was a clash between overt or covert infant feeding idealism and the reality experienced. This is manifest as pivotal points where families perceive that the only solution that will restore family well-being is to stop breast feeding or introduce solids. Immediate family well-being is the overriding goal rather than theoretical longer term health benefits. Feeding education is perceived as unrealistic, overly technical and rules based which can undermine women's confidence. Unanimously families would prefer the balance to shift away from antenatal theory towards more help immediately after birth and at 3–4 months when solids are being considered. Family-orientated interactive discussions are valued above breastfeeding-centred checklist style encounters. Conclusions Adopting idealistic global policy goals like exclusive breast feeding until 6 months as individual goals for women is unhelpful. More achievable incremental goals are recommended. Using a proactive family-centred narrative approach to feeding care might enable pivotal points to be anticipated and resolved. More attention to the diverse values, meanings and emotions around infant feeding within families could help to reconcile health ideals with reality. PMID:22422915

  13. Exploring the Mechanical Anisotropy and Ideal Strengths of Tetragonal B4CO4

    PubMed Central

    Zheng, Baobing; Zhang, Meiguang; Wang, Canjun

    2017-01-01

    First-principles calculations were employed to study the mechanical properties for the recently proposed tetragonal B4CO4 (t-B4CO4). The calculated structural parameters and elastic constants of t-B4CO4 are in excellent agreement with the previous results, indicating the reliability of the present calculations. The directional dependences of the Young’s modulus and shear modulus for t-B4CO4 are deduced in detail, and the corresponding results suggest that the t-B4CO4 possesses a high degree of anisotropy. Based on the strain-stress method, the ideal tensile and shear strengths along the principal crystal directions are calculated, and the obtained results indicate that the shear mode along (001)[100] slip system dominates the plastic deformation of t-B4CO4, which can be ascribed to the breaking of the ionic B-O bonds. The weakest ideal shear strength of 27.5 GPa demonstrates that the t-B4CO4 compound is not a superhard material, but is indeed a hard material. Based on the atomic explanation that the ternary B-C-O compounds cannot acquire high ideal strength, we propose two possible routes to design superhard B-C-O compounds. PMID:28772491

  14. Ideal strength and phonon instability in single-layer MoS2

    NASA Astrophysics Data System (ADS)

    Li, Tianshu

    2012-06-01

    Ideal tensile stress strain relations for single-layer MoS2 are investigated based on first-principle calculation, for biaxial tension and uniaxial tension along zigzag and armchair directions. The predicted ideal tensile strengths and elastic moduli are in excellent agreement with the very recent experimental measurements of Bertolazzi [ACS Nano1936-085110.1021/nn203879f 5, 9703 (2011)] and Castellanos-Gomez [Adv. Mater.ADVMEW0935-964810.1002/adma.201103965 24, 772 (2012)]. It is identified that the tensile strength of single-layer MoS2 are dictated by out-of-plane soft-mode phonon instability under biaxial tension and uniaxial tension along the armchair direction. This failure mechanism, different from that of the truly two-dimensional material graphene, is attributed to the out-of-plane atomic relaxation upon tensile strain. Investigation of the electronic structures of single-layer MoS2 under tensile strain shows the material becomes an indirect semiconductor at small tensile strain (<2%) and turns into metallic before reaching the ideal tensile strength.

  15. Ideal ages for family formation among immigrants in Europe.

    PubMed

    Holland, Jennifer A; de Valk, Helga A G

    2013-12-01

    This paper investigates ideal ages for marriage and parenthood among immigrants from over 160 countries origins living in 25 European countries. Ideals regarding the timing of family formation are indicative of how individuals perceive the family life course and provide insight into family-life aspirations and the meaning attached to these transitions. Using data from the European Social Survey (Round 3, 2006; N=6330) and a cross-classified multilevel modeling approach, we investigate associations between the influences of the dominant family formation timing patterns in countries of origin and settlement, individual-level characteristics, and ideal ages. We make innovative use of a standard demographic measure, the singulate mean age of marriage, to measure family formation patterns. Results suggest that residential context influences are associated with the timing ideals of all migrants, but origin influences seem to be associated with the ideals of only the most recent migrants.

  16. Building a Single Atom Microscope for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Frisbie, Dustin; Johnson, Maegan; Parzuchowski, Kristen; Wenzl, Jennifer; Singh, Jaideep

    2017-01-01

    The primary research goal of this project is to develop a new technique of optical single atom detection to measure rare nuclear reactions at low energies. The 22Ne(α, n)25Mg reaction is of particular interest, as it is thought to be a primary source of neutrons in the s-process of massive stars. Nuclear reaction products are captured in a cryogenically frozen film of noble gas, which can contain a variety of guest atoms. These solids are ideal to use because they are optically transparent and simple to grow and purify. The sample is illuminated by laser light and imaged to identify fluorescing atoms. The atomic transitions of captured atoms indicate which atoms are present; only atoms which are excited at the laser wavelength will fluoresce. This offers high selectivity during experiments. We began development with Yb, a very bright guest atom, being embedded in a host of solid neon in order to study the optical properties necessary for single atom detection. In addition, we study background effects from the laser exciting contaminants in our substrates. We present data that indicates the efficiency with which we can excite and collect fluorescence light with our apparatus, and use it to propose a strategy for the development of Mg single atom detection. This work is generously supported by Michigan State University.

  17. Moral identity as moral ideal self: links to adolescent outcomes.

    PubMed

    Hardy, Sam A; Walker, Lawrence J; Olsen, Joseph A; Woodbury, Ryan D; Hickman, Jacob R

    2014-01-01

    The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes. Data came from a local school sample (Data Set 1: N = 510 adolescents; 10-18 years of age) and a national online sample (Data Set 2: N = 383 adolescents; 15-18 years of age) of adolescents and their parents. All outcome measures were parent-report (Data Set 1: altruism, moral personality, aggression, and cheating; Data Set 2: environmentalism, school engagement, internalizing, and externalizing), whereas other variables were adolescent-report. The 20-item Moral Ideal Self Scale showed good reliability, factor structure, and validity. Structural equation models demonstrated that, even after accounting for moral identity internalization, in Data Set 1 moral ideal self positively predicted altruism and moral personality and negatively predicted aggression, whereas in Data Set 2 moral ideal self positively predicted environmentalism and negatively predicted internalizing and externalizing symptoms. Further, purpose and social responsibility mediated most relations between moral ideal self and the outcomes in Data Set 2. Moral ideal self was unrelated to age but differentially predicted some outcomes across age. Girls had higher levels of moral ideal self than boys, although moral identity did not differentially predict outcomes between genders. Thus, moral ideal self is a salient element of moral identity and may play a role in morally relevant adolescent outcomes. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  18. Presenting the Bohr Atom.

    ERIC Educational Resources Information Center

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  19. Presenting the Bohr Atom.

    ERIC Educational Resources Information Center

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  20. Atomizing nozzle and process

    DOEpatents

    Anderson, I.E.; Figliola, R.S.; Molnar, H.M.

    1993-07-20

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  1. Atoms in Action

    SciTech Connect

    2009-01-01

    This movie produced with Berkeley Lab's TEAM 0.5 microscope shows the growth of a hole and the atomic edge reconstruction in a graphene sheet. An electron beam focused to a spot on the sheet blows out the exposed carbon atoms to make the hole. The carbon atoms then reposition themselves to find a stable configuration. http://newscenter.lbl.gov/press-releases/2009/03/26/atoms-in-action/

  2. HYDROGEN ATOM THERMAL PARAMETERS.

    PubMed

    JENSEN, L H; SUNDARALINGAM, M

    1964-09-11

    Isotropic hydrogen atom thermal parameters for N,N'- hexamethylenebispropionamide have been determined. They show a definite trend and vary from approximately the same as the mean thermal parameters for atoms other than hydrogen near the center of the molecule to appreciably greater for atoms near the end. The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.

  3. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1993-07-20

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  4. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  5. [The 'ideal therapy process': testing a new approach for assessing process quality in inpatient parent-child facilities].

    PubMed

    Musekamp, G; Lukasczik, M; Gerlich, C; Saupe-Heide, M; Löbmann, R; Vogel, H; Neuderth, S

    2014-12-01

    Instruments for external quality assurance in inpatient parent-child rehabilitation and prevention facilities were developed in 2 projects. For the assessment of process quality, we sought an alternative test to the peer review procedure which also places a stronger emphasis on patient perspectives. The aim was to define an "ideal process" as a standard, to develop quantifiable criteria, and to test a multimethod approach which involves different data levels. On the basis of different sources, the "ideal process" for parent-child rehabilitation and prevention and associated criteria were defined by involving an accompanying expert group during a consensus process. Criteria were assessed on different levels: on the rehabilitation/prevention centre level, a questionnaire of process-relevant structural features was used; on the patient level, a case-related routine documentation filled in by clinic staff and an incident-related patient questionnaire were applied. Data were collected in 37 centres (prevention: 19; rehabilitation: 11; 7 offering both types of programmes). Analysis of patient-related data is based on a sample of 1 513 prevention patients and 286 rehabilitation patients. The resulting "ideal process" consists of the stages "preparation", "arrival", "treatment planning", "treatment", "completion of treatment", and "organisation", each containing specific criteria. Exemplarily, the outcomes for the stages "treatment planning" and "treatment" are presented. There is variability both between features and between clinics. The majority of the patients report that the criteria are fulfilled while there are medium to high levels of fulfillment regarding the routine documentation. The criteria of the questionnaire of process-relevant structural features are mostly fulfilled according to the clinics. Agreement between the 3 data levels can be observed. On the basis of the defined "ideal process", the methods that were tested seem to be appropriate to illustrate

  6. Atomic Spectra Database (ASD)

    National Institute of Standards and Technology Data Gateway

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  7. Images of Atoms.

    ERIC Educational Resources Information Center

    Wright, Tony

    2003-01-01

    Recommends using a simple image, such as the fuzzy atom ball to help students develop a useful understanding of the molecular world. Explains that the image helps students easily grasp ideas about atoms and molecules and leads naturally to more advanced ideas of atomic structure, chemical bonding, and quantum physics. (Author/NB)

  8. Materials at Atomic Pressure

    SciTech Connect

    Hicks, Damien

    2010-06-10

    Atomic units give the scale at which quantum processes operate. As combinations of fundamental constants they concisely encapsulate qualities of the atom, e.g. atomic length and energy scales are given by the Bohr radius and the Hartree (or Rydberg) respectively. Although many of these quantities were probed in the early part of the 20th Century the atomic unit of time, at tens of attoseconds, was first probed in 2001. Today, the only atomic unit that remains to be studied experimentally is the atomic unit of pressure, at 294 Mbar (or 147 Mbar in Rydberg atomic units). This is nature’s definition of the ‘high’ in high-pressure science, and it sets the scale for new physics and chemistry. Among experimental facilities, only the NIF can attain and accurately probe atomic pressures. We propose to directly study material properties at these conditions by examining the short-range ordering of atoms using x-ray absorption fine structure spectroscopy (XAFS) of layers in spherical, ignition-type imploding shells. What happens at atomic pressures? The atomic unit of pressure represents the quantum mechanical pressure exerted by an orbiting electron to prevent collapse into the nucleus. Applying external pressure of this magnitude seriously disrupts orbitals and alters the character of the atom itself. Core electron orbitals overlap and chemical bonds are no longer constrained to occur between valence electron orbitals alone. The most direct probe of bonding requires a short-range order diagnostic such as XAFS.

  9. The Nature of Atoms.

    ERIC Educational Resources Information Center

    Holden, Alan

    This monograph was written for the purpose of presenting physics to college students who are not preparing for careers in physics. It deals with the nature of atoms, and treats the following topics: (1) the atomic hypothesis, (2) the chemical elements, (3) models of an atom, (4) a particle in a one-dimensional well, (5) a particle in a central…

  10. Images of Atoms.

    ERIC Educational Resources Information Center

    Wright, Tony

    2003-01-01

    Recommends using a simple image, such as the fuzzy atom ball to help students develop a useful understanding of the molecular world. Explains that the image helps students easily grasp ideas about atoms and molecules and leads naturally to more advanced ideas of atomic structure, chemical bonding, and quantum physics. (Author/NB)

  11. Hyperpolarized Xenon Nuclear Spins Detected by Optical Atomic Magnetometry

    NASA Astrophysics Data System (ADS)

    Yashchuk, V. V.; Granwehr, J.; Kimball, D. F.; Rochester, S. M.; Trabesinger, A. H.; Urban, J. T.; Budker, D.; Pines, A.

    2004-10-01

    We report the use of an atomic magnetometer based on nonlinear magneto-optical rotation with frequency-modulated light to detect nuclear magnetization of xenon gas. The magnetization of a spin-exchange-polarized xenon sample (1.7 c m3 at a pressure of 5bars, natural isotopic abundance, polarization 1% ), prepared remotely to the detection apparatus, is measured with an atomic sensor. An average magnetic field of ˜10 nG induced by the xenon sample on the 10cm diameter atomic sensor is detected with signal-to-noise ratio ˜10 , limited by residual noise in the magnetic environment. The possibility of using modern atomic magnetometers as detectors of nuclear magnetic resonance and in magnetic resonance imaging is discussed. Atomic magnetometers appear to be ideally suited for emerging low-field and remote-detection magnetic resonance applications.

  12. A combined experimental and theoretical approach to atomic scale characterization

    SciTech Connect

    Pennycook, S.J.; Chisholm, M.F.; Yan, Y.; Duscher, G.; Pantelides, S.T.

    1998-02-01

    Recently, the scanning transmission electron microscope has become capable of forming electron probes of atomic dimensions. Through the technique of Z-contrast imaging, it is now possible to form atomic resolution images with high compositional sensitivity from which atomic column positions can be directly determined. An incoherent image of this nature also allows atomic resolution chemical analysis to be performed, by locating the probe over particular columns or planes seen in the image while electron energy loss spectra are collected. Such data represents either an ideal starting point for first principles theoretical calculations or a test of theoretical predictions. The authors present several examples where theory and experiment together give a very complete and often surprising atomic scale view of complex materials.

  13. Electrical Transport in Ultra-Short Atomically Thin Devices

    NASA Astrophysics Data System (ADS)

    Boland, Mathias; Farrokhi, M. Javad; Nasseri, Mohsen; Strachan, Douglas

    Ultra-short nanoscale devices that incorporate atomically-thin materials have the potential to be the smallest electronics. These materials represent the ultimate size-scaling in the vertical dimension and could be ideal as channel, electrode, and dielectric materials for a variety of applications - especially for ultrafast electronics. Such extremely-scaled devices can show unique transport characteristics that depended sensitively on their atomic-scale configurations. Here we report several atomically-thin ultra-short device schemes we have been developing which includes those consisting of single and bilayer graphene channels. Electrical transport measurements show very unique characteristics between these ultra-short devices that are highly sensitive to the atomic layer number. This sensitivity suggests that these ultra-short devices are strongly dependent on the unique chiral nature of the charge carriers in these atomically-thin channel materials.

  14. Squeezed light from multi-level closed-cycling atomic systems

    NASA Technical Reports Server (NTRS)

    Xiao, Min; Zhu, Yi-Fu

    1994-01-01

    Amplitude squeezing is calculated for multi-level closed-cycling atomic systems. These systems can last without atomic population inversion in any atomic bases. Maximum squeezing is obtained for the parameters in the region of lasing without inversion. A practical four-level system and an ideal three-level system are presented. The latter system is analyzed in some detail and the mechanism of generating amplitude squeezing is discussed.

  15. CMS centres worldwide: A new collaborative infrastructure

    SciTech Connect

    Taylor, Lucas; Gottschalk, Erik; /Fermilab

    2010-01-01

    The CMS Experiment at the LHC is establishing a global network of inter-connected 'CMS Centres' for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running 'telepresence' video links. Generic Web-based tools have been developed and deployed for monitoring, control, display management and outreach.

  16. The role of the sexual assault centre.

    PubMed

    Eogan, Maeve; McHugh, Anne; Holohan, Mary

    2013-02-01

    Sexual Assault Centres provide multidisciplinary care for men and women who have experienced sexual crime. These centres enable provision of medical, forensic, psychological support and follow-up care, even if patients chose not to report the incident to the police service. Sexual Support Centres need to provide a ring-fenced, forensically clean environment. They need to be appropriately staffed and available 24 hours a day, 7 days a week to allow prompt provision of medical and supportive care and collection of forensic evidence. Sexual Assault Centres work best within the context of a core agreed model of care, which includes defined multi-agency guidelines and care pathways, close links with forensic science and police services, and designated and sustainable funding arrangements. Additionally, Sexual Assault Centres also participate in patient, staff and community education and risk reduction. Furthermore, they contribute to the development, evaluation and implementation of national strategies on domestic, sexual and gender-based violence. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. IDEAL framework in surgical innovation applied on laparoscopic niche repair.

    PubMed

    Nikkels, C; Vervoort, Anke J M W; Mol, Ben Willem; Hehenkamp, Wouter J K; Huirne, Judith A F; Brölmann, Hans A M

    2017-08-01

    The research objective of the current systematic literature review is to classify the laparoscopic niche repair according to the IDEAL framework of 'innovation stages' and to recommend the required research setting to facilitate safe and properly timed implementation of the technique. In doing so, we are also able to evaluate the practical applicability of the IDEAL framework. A systematic search of the available literature on laparoscopic niche repair was performed in PubMed, Embase, and the Wiley/Cochrane library. Articles were classified according to the IDEAL framework and recommendations were given on additional required research before the technique can be safely implemented. Practical applicability of the IDEAL framework was also evaluated. Introduction of laparoscopic niche repair matches Idea (1) and Development (2a), according to the stages of IDEAL framework, although most studies are retrospective and complications have not been registered structurally in a considerable number of the articles. As feasibility and safety have been more or less established and surgery has been further developed we enter stage 2b (Exploration) and need prospective trials preferably comparing the effectiveness of laparoscopic niche repair to expectant management, the current standard care. Available studies were classified with the use of the IDEAL framework, achieving an overall IDEAL stage to be 2a Development. As clinical outcomes, though poorly registered, have been substantially improved, laparoscopic niche repair needs to be carried forward by more advanced study designs. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Ideal strength of random alloys from first principles

    NASA Astrophysics Data System (ADS)

    Li, Xiaoqing; Schönecker, Stephan; Zhao, Jijun; Johansson, Börje; Vitos, Levente

    2013-06-01

    The all-electron exact muffin-tin orbitals method in combination with the coherent-potential approximation was employed to investigate the ideal tensile strengths of elemental V and Mo solids, and V- and Mo-based random solid solutions. Under uniaxial [001] tensile loading, the ideal tensile strength of V is 11.6 GPa and the lattice fails by shear. Assuming isotropic Poisson contraction, the ideal tensile strengths are 26.7 and 37.6 GPa for V in the [111] and [110] directions, respectively. The ideal strength of Mo is 26.7 GPa in the [001] direction and decreases when a few percent of Tc is introduced in Mo. For the V-based alloys, Cr increases and Ti decreases the ideal tensile strength in all principal directions. Adding the same concentration of Cr and Ti to V leads to ternary alloys with similar ideal strength values as that of pure V. The alloying effects on the ideal strength are explained using the electronic band structure.

  19. Multilevel Atomic Coherent States and Atomic Holomorphic Representation

    NASA Technical Reports Server (NTRS)

    Cao, Chang-Qi; Haake, Fritz

    1996-01-01

    The notion of atomic coherent states is extended to the case of multilevel atom collective. Based on atomic coherent states, a holomorphic representation for atom collective states and operators is defined. An example is given to illustrate its application.

  20. Ideality contours and thermodynamic regularities in supercritical molecular fluids

    NASA Astrophysics Data System (ADS)

    Desgranges, Caroline; Margo, Abigail; Delhommelle, Jerome

    2016-08-01

    Using Expanded Wang-Landau simulations, we calculate the ideality contours for 3 molecular fluids (SF6, CO2 and H2O). We analyze how the increase in polarity, and thus, in the strength of the intermolecular interactions, impacts the contours and thermodynamic regularities. This effect results in the increase in the Boyle and H parameters, that underlie the Zeno line and the curve of ideal enthalpy. Furthermore, a detailed analysis reveals that dipole-dipole interactions lead to much larger enthalpic contributions to the Gibbs free energy. This accounts for the much higher temperatures and pressures that are necessary for supercritical H2O to achieve ideal-like thermodynamic properties.

  1. The place of the ideal observer in medical ethics.

    PubMed

    Churchill, L R

    1983-01-01

    The idea of an ideal observer is frequently employed in ethical reasoning and has recently been introduced into medical ethics. The contemporary use of this idea, however, is deeply flawed. It ignores important social and personal dimensions of ethics. By espousing a perspective of observation removed from history and community, the ideal observer notion encourages a pretense of objectivity and overlooks the distortions of distance. If taken seriously as a model for choice, the ideal observer is incoherent, as it dispenses with the concrete moral agent and the locus of choice. Adam Smith's 'impartial spectator' is examined as a more adequate statement of the need for appreciating diverse perspectives in ethical choices.

  2. Approximating Ideal Filters by Systems of Fractional Order

    PubMed Central

    Li, Ming

    2012-01-01

    The contributions in this paper are in two folds. On the one hand, we propose a general approach for approximating ideal filters based on fractional calculus from the point of view of systems of fractional order. On the other hand, we suggest that the Paley and Wiener criterion might not be a necessary condition for designing physically realizable ideal filters. As an application of the present approach, we show a case in designing ideal filters for suppressing 50-Hz interference in electrocardiogram (ECG) signals. PMID:22291851

  3. The magnetic properties of the hollow cylindrical ideal remanence magnet

    NASA Astrophysics Data System (ADS)

    Bjørk, R.

    2016-10-01

    We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived and the generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown to generate a field exactly twice as large as the equivalent ideal remanence magnet.

  4. Atoms in non-dissipative optical lattices

    NASA Astrophysics Data System (ADS)

    Bergamini, Silvia

    Optical lattices induced by light detuned far from the frequency of any atomic resonance transition are ideal systems in which to develop techniques for the coherent control of atomic motional and internal states. Decoherence arising from spontaneous emission can be eliminated to an arbitrary degree by varying the detuning of the optical field. The atoms trapped in these lattices are to a large extent isolated from environmental disturbances and from each other. The first step towards the coherent control of atoms in a far-detuned lattice is their preparation in a single motional state. In this thesis the preparation of atoms in the ground vibrational state of a two-dimensional far-detuned optical lattice via resolved-sideband Raman cooling is presented. This sideband-cooling scheme involves stimulated Raman transitions between bound vibrational states of a pair of magnetic ground state sublevels, followed by an irreversible step due to optical pumping, resulting in a net loss of one quantum of vibrational energy per cooling cycle. This process provides efficient cooling in two-dimensions and leads to the accumulation of a large fraction of atoms in the 2-D ground vibrational state of a potential well associated with a single Zeeman substate. Experiments aimed at improving and monitoring the characteristics of the lar-detuned lattice and the sideband-Raman cooling efficiency are also described. Parametric excitation experiments and modelling are employed to investigate the degree of anharmonicity of the optical potential and the importance of heating induced by laser intensity noise, whilst Zeeman-state analysis of the sample is performed for monitoring the distribution of atoms over different magnetic sub- states. Finally, spin-polarization experiments are carried out in order to study the paramagnetic properties of the lattice and lead to an evaluation of a spin-temperature for the sample.

  5. Mysterious slapped face rash at holiday centre.

    PubMed Central

    Gunnell, D. J.

    1992-01-01

    OBJECTIVE--To discover the cause of an outbreak of facial rash in a holiday centre. DESIGN--Questionnaire survey of those with rash; analysis of samples of linen. SETTING--Holiday centre in south west England. PATIENTS--98 holiday-makers presenting to the first aid post with a facial rash. INTERVENTION--Replacement of bed linen with new linen in selected parts of the site. RESULTS--The attack rate was 7.0-14.2/1000 for most accommodation areas in the centre, but in one accommodation area the rate was zero. The pH of rinse water from sheets varied from 7.4 to 9.0. Those parts of the accommodation provided with new linen had zero attack rates. CONCLUSION--The facial rash resulted from irritation from washing powder retained owing to insufficient rinsing during laundering. Modifications to the rinsing process led to a gradual disappearance of the rash. PMID:1547418

  6. Emotional intelligence and patient-centred care

    PubMed Central

    Birks, Yvonne F; Watt, Ian S

    2007-01-01

    The principles of patient-centred care are increasingly stressed as part of health care policy and practice. Explanations for why some practitioners seem more successful in achieving patient-centred care vary, but a possible role for individual differences in personality has been postulated. One of these, emotional intelligence (EI), is increasingly referred to in health care literature. This paper reviews the literature on EI in health care and poses a series of questions about the links between EI and patient-centred outcomes. Papers concerning empirical examinations of EI in a variety of settings were identified to determine the evidence base for its increasing popularity. The review suggests that a substantial amount of further research is required before the value of EI as a useful concept can be substantiated. PMID:17682030

  7. Medication errors: pharmacovigilance centres in detection and prevention

    PubMed Central

    Bencheikh, Rachida Soulaymani; Benabdallah, Ghita

    2009-01-01

    Detecting medication errors needs collaboration between various organizations, such as patient safety institutions, pharmacovigilance centres, and poison control centres. In order to evaluate the input of pharmacovigilance centres and poison control centres in detecting and evaluating medication errors a pilot project was initiated by the World Alliance for Patient Safety in collaboration with the Uppsala Monitoring Centre; the Moroccan pharmacovigilance centre acted as project coordinator. As part of this project, a questionnaire on detecting medication errors was circulated to pharmacovigilance centres and poison control centres around the world, in order to assess their ability to detect and analyse medication errors. The results showed that through their databases pharmacovigilance centres can detect, identify, analyse, and classify medication errors and carry out root cause analysis, which is an important tool in preventing medication errors. The duties of pharmacovigilance centres in preventing medication errors include informing health-care professionals about the importance of reporting such errors and creating a culture of patient safety. Pharmacovigilance centres aim to prevent medication errors in collaboration with poison control centres. Such collaboration allows improved detection and improved preventive strategies. In addition, collaboration with regulatory authorities is important in finalizing decisions. Collaboration between pharmacovigilance centres and poison control centres should be strengthened and bridges need to be built linking pharmacovigilance centres, poison control centres, and organizations dedicated to patient safety, in order to avoid duplication of workload. PMID:19594539

  8. Medication errors: pharmacovigilance centres in detection and prevention.

    PubMed

    Bencheikh, Rachida Soulaymani; Benabdallah, Ghita

    2009-06-01

    1. Detecting medication errors needs collaboration between various organizations, such as patient safety institutions, pharmacovigilance centres, and poison control centres. In order to evaluate the input of pharmacovigilance centres and poison control centres in detecting and evaluating medication errors a pilot project was initiated by the World Alliance for Patient Safety in collaboration with the Uppsala Monitoring Centre; the Moroccan pharmacovigilance centre acted as project coordinator. As part of this project, a questionnaire on detecting medication errors was circulated to pharmacovigilance centres and poison control centres around the world, in order to assess their ability to detect and analyse medication errors. 2. The results showed that through their databases pharmacovigilance centres can detect, identify, analyse, and classify medication errors and carry out root cause analysis, which is an important tool in preventing medication errors. 3. The duties of pharmacovigilance centres in preventing medication errors include informing health-care professionals about the importance of reporting such errors and creating a culture of patient safety. Pharmacovigilance centres aim to prevent medication errors in collaboration with poison control centres. Such collaboration allows improved detection and improved preventive strategies. In addition, collaboration with regulatory authorities is important in finalizing decisions. 4. Collaboration between pharmacovigilance centres and poison control centres should be strengthened and bridges need to be built linking pharmacovigilance centres, poison control centres, and organizations dedicated to patient safety, in order to avoid duplication of workload.

  9. Optimizing Data Centre Energy and Environmental Costs

    NASA Astrophysics Data System (ADS)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  10. Role and functions of Poisons Information Centre.

    PubMed

    Lall, S B; Peshin, S S

    1997-01-01

    The Poisons Information Centre (PIC) is a specialized unit providing information on prevention, early diagnosis and treatment of poisoning and hazard management. Most of the developed and many developing countries have well established poison control centres with poisons information service, patient management facility and analytical laboratory. In India, the National Poisons Information Centre (NPIC) was established in February, 1995 in the Department of Pharmacology at the All India Institute of Medical Sciences, New Delhi. The centre provides toxicological information and advice on the management of poisoned patients adopted to the level of the enquirer. The basis of this service are the databases on poisoning, drug reactions and also the continuous and systematic collection of data from the library. This information service is available round the clock. The PIC has the training responsibility extending to medical and other health professionals and community. The NPIC organized two successive training courses for medical professionals and para professionals at all health levels. Further, NPIC is a participant of INTOX project of IPCS/WHO, receiving regular yearly training on the use of INTOX database. Laboratory service is an essential component of a poisons control programme, providing analytical services on emergency basis to help in diagnosis and management. The NPIC is developing facilities for quick diagnosis of poisoning cases. Toxicovigilance and prevention of poisoning is another major function of PIC. The Centre has prepared manuals and leaflets on prevention and management cards on treatment of various poisonings. Thus the Centre provides a service with considerable health benefits, reducing morbidity and mortality from poisoning and gives significant financial savings to the community.

  11. Assessing the quality of care for haemophilia at the Yaoundé reference treatment Centre of Cameroon.

    PubMed

    Yimlefack, Nzometia C; Tagny, Claude T; Ndoumba, Annick M; Pauline, Ngo B; Ngum, Mbanya D

    2017-03-01

    With a recently established Haemophilia Treatment Centre (HTC) in Yaoundé, Cameroon, over a hundred people living with haemophilia have been recruited and followed up at this centre. This study aimed at assessing the quality of haemophilia care provided at the HTC, in order to monitor and improve patient care. In February 2014, the HTC was assessed using recommended markers. Although few, the logistics and reagents for the diagnosis and treatment of haemophilia were available. There were seven trained workers involved with haemophilia care, but the multidisciplinary care team was incomplete. A total of 113 people living with haemophilia (all males) had been registered and regularly followed up at the HTC. This study showed that the HTC of the Yaoundé University Teaching Hospital, although not yet ideal, allows for some degree of haemophilia patient care. Hence, it may be recommended to improve the centre and make it fully established in Cameroon.

  12. Sulfide bonded atomic radii

    NASA Astrophysics Data System (ADS)

    Gibbs, G. V.; Ross, N. L.; Cox, D. F.

    2017-03-01

    The bonded radius, r b(S), of the S atom, calculated for first- and second-row non-transition metal sulfide crystals and third-row transition metal sulfide molecules and crystals indicates that the radius of the sulfur atom is not fixed as traditionally assumed, but that it decreases systematically along the bond paths of the bonded atoms with decreasing bond length as observed in an earlier study of the bonded radius of the oxygen atom. When bonded to non-transition metal atoms, r b(S) decreases systematically with decreasing bond length from 1.68 Å when the S atom is bonded to the electropositive VINa atom to 1.25 Å when bonded to the more electronegative IVP atom. In the case of transition metal atoms, rb(S) likewise decreases with decreasing bond length from 1.82 Å when bonded to Cu and to 1.12 Å when bonded to Fe. As r b(S) is not fixed at a given value but varies substantially depending on the bond length and the field strength of the bonded atoms, it is apparent that sets of crystal and atomic sulfide atomic radii based on an assumed fixed radius for the sulfur atom are satisfactory in that they reproduce bond lengths, on the one hand, whereas on the other, they are unsatisfactory in that they fail to define the actual sizes of the bonded atoms determined in terms of the minima in the electron density between the atoms. As such, we urge that the crystal chemistry and the properties of sulfides be studied in terms of the bond lengths determined by adding the radii of either the atomic and crystal radii of the atoms but not in terms of existing sets of crystal and atomic radii. After all, the bond lengths were used to determine the radii that were experimentally determined, whereas the individual radii were determined on the basis of an assumed radius for the sulfur atom.

  13. Sulfide bonded atomic radii

    NASA Astrophysics Data System (ADS)

    Gibbs, G. V.; Ross, N. L.; Cox, D. F.

    2017-09-01

    The bonded radius, r b(S), of the S atom, calculated for first- and second-row non-transition metal sulfide crystals and third-row transition metal sulfide molecules and crystals indicates that the radius of the sulfur atom is not fixed as traditionally assumed, but that it decreases systematically along the bond paths of the bonded atoms with decreasing bond length as observed in an earlier study of the bonded radius of the oxygen atom. When bonded to non-transition metal atoms, r b(S) decreases systematically with decreasing bond length from 1.68 Å when the S atom is bonded to the electropositive VINa atom to 1.25 Å when bonded to the more electronegative IVP atom. In the case of transition metal atoms, rb(S) likewise decreases with decreasing bond length from 1.82 Å when bonded to Cu and to 1.12 Å when bonded to Fe. As r b(S) is not fixed at a given value but varies substantially depending on the bond length and the field strength of the bonded atoms, it is apparent that sets of crystal and atomic sulfide atomic radii based on an assumed fixed radius for the sulfur atom are satisfactory in that they reproduce bond lengths, on the one hand, whereas on the other, they are unsatisfactory in that they fail to define the actual sizes of the bonded atoms determined in terms of the minima in the electron density between the atoms. As such, we urge that the crystal chemistry and the properties of sulfides be studied in terms of the bond lengths determined by adding the radii of either the atomic and crystal radii of the atoms but not in terms of existing sets of crystal and atomic radii. After all, the bond lengths were used to determine the radii that were experimentally determined, whereas the individual radii were determined on the basis of an assumed radius for the sulfur atom.

  14. Byurakan Astrophysical Observatory as Cultural Centre

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Farmanyan, S. V.

    2016-12-01

    NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts.

  15. [Certification of healthcare centres: Taking stock].

    PubMed

    Ziegler, Kai; Risthaus, Franziska; Strupeit, Steve

    2014-01-01

    Healthcare facilities can use certificates to position themselves as experts to their clients and to distinguish themselves from their competitors. Different AWMF societies have addressed this topic und offer healthcare facilities the chance to get certified as a centre. In the course of this the societies develop curricula. Certification according to these curricula is then performed by the healthcare facilities or by an accredited agency. The different certificates show large differences in their certification requirements, which makes comparing them difficult. The present publication provides an overview of societies addressing certification and centres that are currently being certified. Copyright © 2014. Published by Elsevier GmbH.

  16. Byurakan Astrophysical Observatory as Cultural Centre

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Farmanyan, S. V.

    2017-07-01

    NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts. Keywords: Byurakan Astrophysical Observatory, architecture, botanic garden, tourism, Cultural Astronomy.

  17. Bureaucracy, professionalization and school centred innovation strategies

    NASA Astrophysics Data System (ADS)

    Morris, Paul

    1990-03-01

    This paper examines an attempt to promote a school centred innovation strategy within a highly centralized educational system. The School Based Curriculum Project Scheme, which was introduced into Hong Kong in 1988, is analysed in terms of a professional-bureaucratic dichotomy. It is argued that the operational details of the scheme are designed to satisfy a range of bureaucratic concerns and these are not conducive to promoting the professional work ethic which is required for school centred innovation. Finally the paper identifies the implications which arise for policies designed to promote curriculum innovation.

  18. Re-cataloging Joint Astronomy Centre (JAC) Library Book Collection

    NASA Astrophysics Data System (ADS)

    Lucas, A.; Zhang, X.

    2007-10-01

    The Joint Astronomy Centre operates two telescopes: the James Clerk Maxwell Telescope and the United Kingdom Infrared Telescope. In the JAC's 25-year history, their library was maintained by a number of staff ranging from scientists to student assistants. This resulted in an inconsistent and incomplete catalog as well as a mixture of typed, hand written, and inaccurate call number labels. Further complicating the situation was a backlog of un-cataloged books. In the process of improving the library system, it became obvious that the entire book collection needed to be re-cataloged and re-labeled. Readerware proved to be an inexpensive and efficient tool for this project. The software allows for the scanning of barcodes or the manual input of ISBNs, LCCNs and UPCs. It then retrieves the cataloging records from a number of pre-selected websites. The merged information is then stored in a database that can be manipulated to perform tasks such as printing call number labels. Readerware is also ideal for copy cataloging and has become an indispensable tool in maintaining the JAC's collection of books.

  19. Do the Particles of an Ideal Gas Collide?

    ERIC Educational Resources Information Center

    Lesk, Arthur M.

    1974-01-01

    Describes the collisional properties as a logically essential component of the ideal gas model since an actual intraparticle process cannot support observable anisotropic velocity distributions without collisions taken into account. (CC)

  20. Computer program for calculation of ideal gas thermodynamic data

    NASA Technical Reports Server (NTRS)

    Gordon, S.; Mc Bride, B. J.

    1968-01-01

    Computer program calculates ideal gas thermodynamic properties for any species for which molecular constant data is available. Partial functions and derivatives from formulas based on statistical mechanics are provided by the program which is written in FORTRAN 4 and MAP.

  1. Ideal Based Cyber Security Technical Metrics for Control Systems

    SciTech Connect

    W. F. Boyer; M. A. McQueen

    2007-10-01

    Much of the world's critical infrastructure is at risk from attack through electronic networks connected to control systems. Security metrics are important because they provide the basis for management decisions that affect the protection of the infrastructure. A cyber security technical metric is the security relevant output from an explicit mathematical model that makes use of objective measurements of a technical object. A specific set of technical security metrics are proposed for use by the operators of control systems. Our proposed metrics are based on seven security ideals associated with seven corresponding abstract dimensions of security. We have defined at least one metric for each of the seven ideals. Each metric is a measure of how nearly the associated ideal has been achieved. These seven ideals provide a useful structure for further metrics development. A case study shows how the proposed metrics can be applied to an operational control system.

  2. Susceptibility for thin ideal media and eating styles.

    PubMed

    Anschutz, Doeschka J; Engels, Rutger C M E; Van Strien, Tatjana

    2008-03-01

    This study examined the relations between susceptibility for thin ideal media and restrained, emotional and external eating, directly and indirectly through body dissatisfaction. Thin ideal media susceptibility, body dissatisfaction and eating styles were measured in a sample of 163 female students. Structural equation modelling was used for analyses, controlling for BMI. Higher susceptibility for thin ideal media was directly related to higher scores on all eating styles, and indirectly related to higher restrained and emotional eating through elevated levels of body dissatisfaction. So, thin ideal media susceptibility was not only related to restraint through body dissatisfaction, but also directly. Emotional eaters might be more vulnerable for negative affect, whereas external eaters might be more sensitive to external cues in general.

  3. Contributions of Ideal Observer Theory to Vision Research

    PubMed Central

    Geisler, Wilson S.

    2010-01-01

    An ideal observer is a hypothetical device that performs optimally in a perceptual task given the available information. The theory of ideal observers has proven to be a powerful and useful tool in vision research, which has been applied to a wide range of problems. Here I first summarize the basic concepts and logic of ideal observer analysis and then briefly describe applications in a number of different areas, including pattern detection, discrimination and estimation, perceptual grouping, shape, depth and motion perception and visual attention, with an emphasis on recent applications. Given recent advances in mathematical statistics, in computational power, and in techniques for measuring behavioral performance, neural activity and natural scene statistics, it seems certain that ideal observer theory will play an ever increasing role in basic and applied areas of vision science. PMID:20920517

  4. Work-Life Balance and Ideal Worker Expectations for Administrators

    ERIC Educational Resources Information Center

    Wilk, Kelly E.

    2016-01-01

    This chapter explores the work-life experiences of administrators as well as whether and how the ideal worker model affects those experiences. Departmental and supervisory differences and technology complicate administrators' work-life experiences.

  5. 2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' Hot Springs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. SECTIONAL BOILER '#4 IDEAL RED FLASH.' - Hot Springs National Park, Bathhouse Row, Ozark Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  6. Work-Life Balance and Ideal Worker Expectations for Administrators

    ERIC Educational Resources Information Center

    Wilk, Kelly E.

    2016-01-01

    This chapter explores the work-life experiences of administrators as well as whether and how the ideal worker model affects those experiences. Departmental and supervisory differences and technology complicate administrators' work-life experiences.

  7. Nonlinear gel electrophoresis: an analogy with ideal fluid flow.

    PubMed

    Dennison, C; Phillips, A M; Nevin, J M

    1983-12-01

    The behavior of electrolytes undergoing electrophoresis in various shaped gels was investigated using bromphenol blue as a model electrolyte. The results suggest that during gel electrophoresis, small electrolytes behave in a manner analogous to the flow of ideal, irrotational fluids.

  8. Atomic Force Microscopy of Biological Membranes

    PubMed Central

    Frederix, Patrick L.T.M.; Bosshart, Patrick D.; Engel, Andreas

    2009-01-01

    Abstract Atomic force microscopy (AFM) is an ideal method to study the surface topography of biological membranes. It allows membranes that are adsorbed to flat solid supports to be raster-scanned in physiological solutions with an atomically sharp tip. Therefore, AFM is capable of observing biological molecular machines at work. In addition, the tip can be tethered to the end of a single membrane protein, and forces acting on the tip upon its retraction indicate barriers that occur during the process of protein unfolding. Here we discuss the fundamental limitations of AFM determined by the properties of cantilevers, present aspects of sample preparation, and review results achieved on reconstituted and native biological membranes. PMID:19167286

  9. Measurable Control System Security through Ideal Driven Technical Metrics

    SciTech Connect

    Miles McQueen; Wayne Boyer; Sean McBride; Marie Farrar; Zachary Tudor

    2008-01-01

    The Department of Homeland Security National Cyber Security Division supported development of a small set of security ideals as a framework to establish measurable control systems security. Based on these ideals, a draft set of proposed technical metrics was developed to allow control systems owner-operators to track improvements or degradations in their individual control systems security posture. The technical metrics development effort included review and evaluation of over thirty metrics-related documents. On the bases of complexity, ambiguity, or misleading and distorting effects the metrics identified during the reviews were determined to be weaker than necessary to aid defense against the myriad threats posed by cyber-terrorism to human safety, as well as to economic prosperity. Using the results of our metrics review and the set of security ideals as a starting point for metrics development, we identified thirteen potential technical metrics - with at least one metric supporting each ideal. Two case study applications of the ideals and thirteen metrics to control systems were then performed to establish potential difficulties in applying both the ideals and the metrics. The case studies resulted in no changes to the ideals, and only a few deletions and refinements to the thirteen potential metrics. This led to a final proposed set of ten core technical metrics. To further validate the security ideals, the modifications made to the original thirteen potential metrics, and the final proposed set of ten core metrics, seven separate control systems security assessments performed over the past three years were reviewed for findings and recommended mitigations. These findings and mitigations were then mapped to the security ideals and metrics to assess gaps in their coverage. The mappings indicated that there are no gaps in the security ideals and that the ten core technical metrics provide significant coverage of standard security issues with 87% coverage. Based

  10. Ideal gas behavior of a strongly coupled complex (dusty) plasma.

    PubMed

    Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

    2013-07-05

    In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

  11. Ideal spiral bevel gears: A new approach to surface geometry

    NASA Technical Reports Server (NTRS)

    Huston, R. L.; Coy, J. J.

    1980-01-01

    The fundamental geometrical characteristics of spiral bevel gear tooth surfaces are discussed. The parametric representation of an ideal spiral bevel tooth is developed based on the elements of involute geometry, differential geometry, and fundamental gearing kinematics. A foundation is provided for the study of nonideal gears and the effects of deviations from ideal geometry on the contact stresses, lubrication, wear, fatigue life, and gearing kinematics.

  12. Ideal spiral bevel gears - A new approach to surface geometry

    NASA Technical Reports Server (NTRS)

    Huston, R. L.; Coy, J. J.

    1980-01-01

    This paper discusses the fundamental geometrical characteristics of spiral bevel gear tooth surfaces. The parametric representation of an ideal spiral bevel tooth is developed. The development is based on the elements of involute geometry, differential geometry, and fundamental gearing kinematics. A foundation is provided for the study of nonideal gears and the effects of deviations from ideal geometry on the contact stresses, lubrication, wear, fatigue life, and gearing kinematics.

  13. Fixing women: devaluation, idealization, and the female fetish.

    PubMed

    Waites, E A

    1982-01-01

    A particular ideal of femininity which has long been popular in our culture is the image of the esthetically perfect but behaviorally compliant woman. By comparing two clinical cases, I have attempted to show that this stylized image is sometimes part of a specific defensive structure, enacted in extreme forms as part of a perverse ritual. The idealized image is a secondary formation with roots in early transitional representations. As an adult defense, it isolates devalued attributes, particularly anal attributes, from an esthetic ideal and enables the narcissistically disturbed individual to effect an illusion of separation while maintaining compulsive control over a needed object. The enactment of this defensive pattern frequently requires the cooperation of a partner. Women comply not only for masochistic reasons or because of intimidation, but because the fetishistic ritual itself is often an important part of their defensive armory. Women who rely on the idealization provided by a partner as the major source of their self-esteem are sometimes willing to accept pathological features of a partnership rather than give up this narcissistic support. At the more creative end of the continuum between pathological and adaptive transitional representations, the idealized image of woman may lend a playful romantic tone to relationships between men and women. In its most compulsive manifestations, however, it tends to perpetuate superficiality and impedes understanding between the sexes. Patients in whom the ideal is elaborated in its most distorted forms offer a useful opportunity to explore the roots of these phenomena.

  14. Estimation ROC curves and their corresponding ideal observers

    NASA Astrophysics Data System (ADS)

    Clarkson, Eric

    2007-03-01

    The LROC curve may be generalized in two ways. We can replace the location of the signal with an arbitrary set of parameters that we wish to estimate. We can also replace the binary function that determines whether an estimate is correct by a utility function that measures the usefulness of a particular estimate given the true parameter set. The expected utility for the true-positive detections may then be plotted versus the false-positive fraction as the detection threshold is varied to generate an estimation ROC curve (EROC). Suppose we run a 2AFC study where the observer must decide which image has the signal and then estimate the parameter set. Then the average value of the utility on those image pairs where the observer chooses the correct image is an estimate of the area under the EROC curve (AEROC). The ideal LROC observer may also be generalized to the ideal EROC observer, whose EROC curve lies above those of all other observers. When the utility function is non-negative the ideal EROC observer shares many properties with the ideal ROC observer, which can simplify the calculation of the ideal AEROC. When the utility function is concave the ideal EROC observer makes use of the posterior mean estimator. Other estimators that arise as special cases include maximum a posteriori estimators and maximum likelihood estimators. Multiple signals may be accomodated in this framework by making the number of signals one of the parameters in the set to be estimated.

  15. Writing Centre Tutoring Sessions: Addressing Students' Concerns

    ERIC Educational Resources Information Center

    Winder, Roger; Kathpalia, Sujata S.; Koo, Swit Ling

    2016-01-01

    The guiding principle behind university writing centres is to focus on the process of writing rather than the finished product, prioritising higher order concerns related to organisation and argumentation of texts rather than lower order concerns of grammar and punctuation. Using survey-based data, this paper examines students' concerns regarding…

  16. Writing Centre Tutoring Sessions: Addressing Students' Concerns

    ERIC Educational Resources Information Center

    Winder, Roger; Kathpalia, Sujata S.; Koo, Swit Ling

    2016-01-01

    The guiding principle behind university writing centres is to focus on the process of writing rather than the finished product, prioritising higher order concerns related to organisation and argumentation of texts rather than lower order concerns of grammar and punctuation. Using survey-based data, this paper examines students' concerns regarding…

  17. In the Field: The Canadian Ecology Centre.

    ERIC Educational Resources Information Center

    Magee, Clare

    2000-01-01

    The Canadian Ecology Centre (Ontario) offers year-round residential and day programs in outdoor and environmental education for secondary students, field placement and internship opportunities for college students, and ecotourism programs, while providing employment and tax revenues to the local community. Dubbed consensus environmentalism, the…

  18. Centring the Subject in Order to Educate

    ERIC Educational Resources Information Center

    Webster, R. Scott

    2007-01-01

    It is important for educators to recognise that the various calls to decentre the subject--or self--should not be interpreted as necessarily requiring the removal of the subject altogether. Through the individualism of the Enlightenment the self was centred. This highly individualistic notion of the sovereign self has now been decentred especially…

  19. Self Assessment and Student-Centred Learning

    ERIC Educational Resources Information Center

    McDonald, Betty

    2012-01-01

    This paper seeks to show how self assessment facilitates student-centred learning (SCL) and fills a gap in the literature. Two groups of students were selected from a single class in a tertiary educational institution. The control group of 25 was selected randomly by the tossing of an unbiased coin (heads = control group). They were trained in the…

  20. Oo-Za-We-Kwun Centre Incorporated

    ERIC Educational Resources Information Center

    Findlay, P. R.; And Others

    1976-01-01

    The Centre is described as being designed to help native people participate more effectively in a modern Canadian environment. The residential family program includes a five-week Life Skills course followed by a two-year transfer of learning period during which counseling, paid employment, and community activities are available. (Author/MS)